Final Report Summary - CONDIMON (Development of an in-line multi-parameter oil condition monitoring system including a novel oil corrosion sensor for bio-gas operated power generator engines)
Executive Summary:
Biomass coming from biological material such as manure, organic waste, trees and plants is one of the largest and most important renewable energy options at present. Biogas production has significantly risen across the EU in the past years. According to the statistics of the European Biogas Association today there are more than 13 800 biogas plants in Europe with an installed gross capacity of 7400 Megawatt. By 2020 methane production will expectedly double compared to a decade ago and reach 24.2 billion cubic meter.
However, process optimisation through innovative technologies still has much potential to increase the productivity and profitability of existing and newly established biogas plants. For example biogas operations often suffer from high costs associated with quality degradation of oil that can attack essential engine parts. As oil analysis can give a reliable overview of the current condition of the engine it can be considered as an essential aspect of optimally operating industrial engines.
The main objective of the CONDIMON project was to create a validated prototype of a multisensory system suitable for the online monitoring of the lubricant oil of biogas generators running at the facilities of project partners. The prototype incorporates a novel sensor that can directly measure the corrosion (acidification) of the lubricant, a critical parameter in combustion engines especially in case of biofuel based operations. Our main objective was to create an efficient condition monitoring system that returns the investment within two years for existing installations and can be seamlessly integrated into new biogas based electric generators.
The CONDIMON multi-parameter oil lubricant monitoring system was installed, validated and long-term tested at the biogas plants of two consortium members, RYTEC (Germany) and BKG (Austria). During the development process we always took in mind to achieve a prototype that is as close to market entry as possible. Thus, we concluded with fully integrated sensor bodies and DAQ system that require minimal modifications before turning into a marketable product.
We also developed an extensive knowledge base of oil lubricant data that is unique among competitors. This work is based on one and a half year of measurements in laboratory, using artificial alteration, and real environment data gathered from consortium members BKG and RYTEC. This enables us to give both the raw physical parameters of the oil lubricant, like competitors do, and – as unique selling point – to interpret the data suited to the end-user expectations and to give decision support.
Based on the results of the project, we claim that CONDIMON system lowers operation costs, thus contributes to the competitiveness of biogas sector SMEs. The number of biogas farms in Europe is estimated to more than 15 000 of which approx. 6 500 are farm scale plants, with more than 1 000 new installations each year, based on the last 3 years growth statistics.
Project Context and Objectives:
Farm-scale biogas plants are making their way on meeting the requirements on the use of biomass set by 2020 however their operation still strongly depends on subsidies. There is still a huge potential to optimize operational processes thus financial profitability in the EU-27. The aim of CMMS, UNICOMP, BKG, MAZZY and RYTEC was to develop an innovative online condition monitoring system which would allow cost-effective and safe operation.
The biogas sector has seen a rapid development in recent years and continues to grow. For farm, small and middle scale power plants, biomass is usually utilized by digestion to biogas as fuel for co-generation engines (electricity + heat).
This kind of energy production is typically performed by SMEs such as like RYTEC and BKG, utilizing the biogas in combined power units consisting of a generator and an internal combustion engine, which was the target market for the CONDIMON project, providing potential benefit for a large number of SMEs.
However, bio-gas engine operators suffer from high costs associated with maintenance due to the special chemical attack on the engine and engine oil resulting from biogas operation. This adds to the fact that biogas based power generation is still not competitive with other (also renewable) energy sources and highly relies on governmental subsidies. Oil analysis gives a reliable overview of the current condition of the engine as it can be considered the “lifeblood of industrial engines” as declared by CMMS, leading global provider of oil monitoring and testing solutions.
Beside oxidative degradation, the main oil change criteria in farm scale biogas engines are the acidity and water content (relative humidity). Compared to conventional fuels, bio-fuelled engines are more severely exposed to acidification of the lubricating oil and humidity increase. This results from the fact that bio-fuels often contain significantly higher amounts of chemically aggressive elements building aggressive acidic compounds during combustion and thus contaminating the oil. On the other hand, water increases the oxidation rate of the oil that attacks the base stock and additives, and decreases its load bearing capability. This is especially the case for biogas obtained from agricultural waste or animal mature (as typical for farm-scale biogas plants) and that in spite of costly gas-cleaning efforts. High-end gas cleaning equipment is not economical for farm scale biogas plants (SMEs), only for large-scale biogas plants, but even there the acidification (which is linked to the corrosiveness) and humidity of the oil remains a major issue.
These facts highlight the need for online monitoring of oil quality both for economic and ecological considerations. Quality degradation in oil can attack essential engine parts leading to increased wear and corrosive wear and to early failing of the machine. Although there is much scientific research and patents proposing oil quality sensor approaches for certain parameters, there are currently no commercially available sensor systems measuring all key parameters of oil quality necessary to determine reliably the necessity of oil maintenance.
The concept of CONDIMON
The CONDIMON system is based on online monitoring of oil quality in biogas engines by means of a multi-parameter sensor system and evaluation software based on a knowledge base for best practice in maintenance.
CONDIMON combines 5 sensors for the measurement of conductivity, rel. permittivity, rel. humidity, corrosion and temperature. By means of these sensors the level of oil deterioration can be monitored.
The knowledge base was created applying the numerous input data generated during the field tests and laboratory analysis using artificial alteration and contains an algorithm to provide trends in oil quality to easily interpret the indication of an oil change.
The system provides industrial compatibility for additional sensor extension by industrial standard interfaces and bus systems to meet special needs.
Innovation
Beside the integration and combined evaluation of multiple state-of-the-art online oil condition sensor types, the CONDIMON system includes a novel corrosion sensor that provides indication about the oil’s degree of degradation mainly expressed as acidity, by determining the actual rate of corrosion. In bio-gas fuelled engines, increased acidity is one of the crucial oil change criteria and root causes of lubricant degradation and machine failures.
The proposed multi-parameter system is supplemented with a knowledge base and an expert system for signal evaluation in order to:
• safely extend the oil changes interval by 25% (expected in average), while
• preventing any unexpected engine damage by early detection of adverse conditions.
Among others, it was also a goal of this project to provide a significantly simplified indication of oil condition to the end user based on the development of a knowledge base for integrated signal evaluation.
The highly innovative corrosion sensing concept used for acidity measurement is based on the contactless measurement of the remaining metallic volume of a sacrificial layer exposed to corrosion. There is a strong correlation between the oil’s corrosiveness and the acid content based on the research carried out by AC²T in the recent years, during which the basis of this new measurement method was established. Now, in this project the results of laboratory experiments were utilized to develop a novel industrial grade sensor as a part of the proposed multi-parameter sensor system.
The proposers of the CONDIMON technology recognized the potential business opportunity to develop a low-cost technology for the monitoring of oil quality in biogas driven engines, which is an emerging market due to the need for CO2 neutral energy in Europe.
The CONDIMON product will be sold on newly installed biogas plants and for retrofitting existing engines by RYTEC. MAZZY will provide the data acquisition and evaluation software packages while UNICOMP will produce the multisensory sensor module and the data acquisition hardware in line with the contract volumes. RYTEC installs the system at customer’s site and as a first selling point distributes the profit to partners by their respective shares based on the production. The profit for RYTEC is established by the cost of installation. UNICOMP is considered to provide the disposable oil corrosion sensing elements (estimated 10 pieces per year per installations) that are needed for the operation of the sold systems and benefits from the corresponding profits.
Scientific and Technological Objectives:
• Scientific objectives:
• To provide optimized technical specifications for the corrosion sensor industrialization in point of robustness, compatibility and maintenance.
• To provide algorithm of the signal evaluation of the multisensory environment.
• To create a knowledge base for the evaluation of the multisensory system signals to provide an easy-to-interpret indication for the end-user, including correlations to standard parameters.
• Technological and application related objectives:
• To design a sensor body withstanding operating temperatures referring to oil temperatures up to 120°C, oil pressures of 10 bar and vibrations; but allowing an easy ex-post upgrade to existing engines as well as an easy replacement of the sensing element of the corrosion sensor.
• To deliver a disposable sensing element, replaceable at the time of oil change maintenance.
• To deliver a prototype integrating all components and the evaluation software.
• To validate the system in field tests at least 3 end users utilizing different biogas types and to investigate correlations to conventional oil analysis as base for standardization.
• To develop signal evaluation software implementing the developed knowledge base and evaluation algorithm to enable an easy-to-interpret indication.
• To prepare the prototype for commercialization during the project.
• Market related objectives:
• To achieve a market price for the multi-sensor system in the medium to upper price range of commercial sensor systems with widely comparable features, and a market price for the disposable sensing element significantly below costs for lubricant analysis.
• To effectively demonstrate the CONDIMON system in field-tests for dissemination at the demonstration plants provided by BKG and RYTEC.
• Training, dissemination and exploitation objectives:
• To manage the foreground knowledge, as well as to protect and to use the results to the best advantage of the SME proposers.
• To perform training and dissemination activities, and to ensure that SME participants will be able to assimilate the results by working out an appropriate exploitation strategy.
• To provide a methodology as a tool for the technical SMEs enabling them to “adopt and adapt” the CONDIMON system (i.e. evaluation algorithms) to engine systems with other fuel types in the post project phase ensuring better exploitation of the results
Project Results:
The objectives were achieved by carrying out the following development tasks in the frame of the CONDIMON project: existing know-how within the Consortium was compiled so that we could address the most up-to-date requirements and finalize our preliminary system specifications (WP1). During this task, we emphasized the marketing aspects, so that the prototype can be sold on market short after the execution of the project. Finally, we concluded with a system of fully integrated oil condition sensor with a flexible data acquisition hardware and software so that the system is capable of providing useful analysis data online.
Four R&D work packages were carried out in parallel in order to meet the defined system specifications. The novel corrosion sensor was further developed (WP2) so it can be integrated into the CONDIMON system. Besides, the sensor electronics of a compact multi-parameter sensor measuring rel. permittivity, conductivity, rel. humidity and temperature of the lubricant were developed.
The data acquisition (DAQ) hardware (WP3) was developed based on a custom PLC system in order to meet the requirements of harsh industrial environment. The central PLC unit is connected to the PC installed in the control rooms of biogas plants. The DAQ software (WP4) shows online data trends to the maintainers and provides data logging, warnings and system alarms adjusted to specific thresholds.
The knowledge base and the signal processing algorithm were developed in WP5. This development was based on the input data gathered from laboratory analyses based on artificial alteration and real-environment field tests carried out in Frankfurt (RYTEC) and Güssing (BKG).
Finally, in WP6 all the system parts developed in the first five work packages were integrated and installed for field tests. The field tests were running from month 12 until the end of the project at facilities of RYTEC and BKG. By the end of the project, the final CONDIMON system was validated and demonstrated in this work package.
In the following the most important results of these work packages are summarized.
WP1 – System specifications
The objectives targeted in the Condimon project were achieved by the development of a multi-parameter sensor system. The main blocks are the oil sensors, the interface electronics, the PLC based data acquisition and PC based signal processing, graphical user interface (GUI) and control unit. Following specifications are fulfilled by the current Condimon Sensor System:
General requirements
• IP protection: IP66
• Electrical power: 12-24V
• Communication interfaces of existing data loggers/controllers that the sensor system will be op-tionally connected to 4-20mA
• Environmental considerations regarding indoor/outdoor operation, temperature and humidity range, stability against vibration and impact
• Mechanical considerations regarding low weight, size, installation and others, e.g. precautions for implementation in existing gas engines
• Market price – target values
o Multi-sensor system in the medium to upper price range of commercial sensor systems with comparable features where possible
o Disposable sensing element significantly below costs for lubricant analysis
Sensors
• Type of sensors: Corrosion, rel. permittivity, conductivity, rel. humidity and temperature
• Operational pressure range: 0 to 10 bar
• Operational temperature limitations for the sensor body and the sensing element referring to oil temperature up to 120°C
Control system
• Hardware requirements
o Dual Ethernet connection
o Minimum XScale 500MHz processor
o Minimum 64M RAM
o Non-volatile memory for parameters
o Touch screen for local operations
o CF or USB slot for high capacity storage
• Interface requirements
o Profibus
o 4-20 mA
o Ethernet
Software requirements
The collected sensor data are stored and/or pre-processed locally. The software of the system should fulfil the needs listed below. The system also should provide a Human Machine Interface to enable the operator to quickly interference if necessary.
Key software features:
• Read and store the sensor data
• Pre-process option for the sensor data (average, integrate, maximum, minimum, etc.)
• Human Machine Interface for parameter optimization
• Relation to existing control systems, in particular Ethernet and 4-20mA
WP2 – Sensor development
Based on specific background of AC²T on the corrosion sensor and on the system specifications, the concept of the industrial design of the corrosion sensor was developed. Key element of the corrosion sensor is the sensing element with the sacrificial layer which is corroded by oil that contains corrosive compounds. As sacrificial material, lead was used as it corrodes by organic acids that are built up during the engine operation. The sensing element can be easily replaced on the sensor body. During engine operation, corrosion process on sensing element, i.e. value for the remaining area of the sacrificial layer, is monitored by contact-less readout electrodes. Measurement is done via frequency of a RC oscillator connected to a microcontroller. Further parts of the microcontroller are reading the temperature of the temperature sensor for compensation and giving the calculated value to the standardized output. According to the system specifications, the output is a current loop (4 - 20 mA).
Important part of the industrial corrosion sensor is a changeover device to enable the exchange of the sensing element at any time, in particular during operation.
According to the DoW, the concept of the corrosion sensor was combined with the other commercially available sensor types to provide the Condimon multi-parameter sensor. In the following, the details of the corrosion sensor and the multi-parameters sensor can be found.
Corrosion sensor
The key component of the corrosion sensor is the sacrificial layer in the sensing element. In the previous work of AC²T, lead as sacrificial layer showed good results as it is corroded by a defined amount of organic acids built up during the use of the oil. Therefore, lead as sacrificial layer was also used for the CONDIMON project.
Further task of the sensing element is to take up the structured readout electrodes and a sacrificial layer thus building a capacitor element. This sensing element is considered as a varying capacitance (vs acid content) and is measured by a custom capacitance measurement readout electronics. The main task of the readout electronics is the determination of the remaining area of the sacrificial layer. The remaining area can be well represented by the measurement of the capacitance between the readout electrodes.
In order to have a reliable measurement, the temperature is necessary for the compensation of temperature dependencies of the system. As the area for a temperature sensor is limited, a digital temperature sensor is used.
According to the specifications, 4 - 20 mA current outputs of the corrosion sensor are preferred. Therefore, the digital signals of the microcontroller have to be converted to analog ones. For this operation, a digital-analog converter (DAC) is needed which converts the signal to a defined current level.
It was also an important task to develop a reliable mechanism for fixing the sensing element in the protecting house. The design of the fixing system provides hold of the sensing element in the protecting house during storage and exchange of the sensing element. During operation, the sensing element is clamped between the sensor body and the protecting house to avoid that the sensing element falls out of the protection house.
Corrosion sensor performance
The developed corrosion sensor was first evaluated by means of artificial alteration, which is commonly used at AC²T for evaluation of sensor systems. The lubricants for this evaluation were gas engine oils that were degraded in the “hot” alteration zone of the alteration device by blowing air through the oil. The altered oil was transferred continuously to the “cold” sensor zone and backwards. Periodically taken oil samples were analysed in the laboratory to follow the oil condition of the degraded oil.
The entire CONDIMON sensor system was accordingly evaluated.
Among others, laboratory analyses included the measurement of the total base number (TBN) and neutralization number (NN). TBN indicates the amount of bases (base reserve) in an oil possible to neutralize acidic components taken up or formed upon lubricant alteration whereas NN refers to the amount of acidic components in an oil. A steady decrease of the TBN and steady increase of the NN can be observed. Common oil change criteria were applied. Typically, at a NN increase of about 1 mg KOH/g and a TBN decrease of about 2 mg KOH/g, respectively, the initial point for corrosion was reached.
Based on the findings achieved, some modifications of the sacrificial layer were performed to adapt the initial point for corrosion according to the oil, fuel and engine type.
CONDIMON multi-parameter sensor
In order to achieve the CONDIMON multi-parameter sensor, significant efforts from RTD partners (AC²T and ATEKNEA) were undertaken. Basically, the remaining sensors for conductivity, relative permittivity and relative humidity were integrated into the existing prototype of the corrosion sensor already equipped with a temperature sensor. The final setup is as follows:
For the measurement of the relative humidity of the lubricant, a capacitive humidity sensor element was used. This sensor is specially designed for measuring the oil humidity. Its small dimensions permitted an easy integration into the existing corrosion sensor setup.
For the measurement of the electrical conductivity and relative permittivity, a sensor element with similar dimension as for the relative humidity was used. This sensor element is a two electrode system with a comb structure. Furthermore, the sensor element has also integrated a PT1000 sensor for measurement of the oil temperature. Evaluation of the sensor element carried out by AC²T confirmed the possibility to measure the conductivity in the range needed for gas engine oils.
The integration of the sensing elements and the sensor electronics were carried out by AC²T and ATEKNEA. The sensors for relative humidity as well as conductivity and permittivity are installed into the sensor body of the corrosion sensor. For the standardized sensor output, also analog outputs 4-20mA were integrated.
A sine generator is used to apply an alternating voltage to the sensor elements (conductivity sensor element and humidity sensor element). The generated alternating voltage with defined frequency is applied to the sensor elements and the electrical current through the element is measured using an operational amplifier as trans-impedance amplifier. The output of the operational amplifier is proportional to the current and hence also to the conductance and capacitance, respectively.
Analog to digital and digital to analog conversions are carried out in a similar way as discussed for the corrosion sensor. All the parameters are available at the 4-20 mA output in pulsed mode with a sequence according to the protocol.
WP3 – DAQ hardware development
In this work package, the PLC based data acquisition hardware was developed by ATEKNEA. This sub-system has a two level hierarchy including data collector modules at the engines (sub-station) and a coordinator module (main station) in the control room of the plant. All the control electronics modules are based on industrial modules. In the following the main parts of the design is presented.
System topology
During the design of the system topology, the following characteristics of the targeted application fields were taken into account:
• The distance between the biogas engines of the same plant can be several meters. The harsh environment and the presence of potentially disturbing electromagnetic signals re-quire that the transmission line of unconditioned, raw sensor signals should be as short as possible.
• Therefore, every biogas engine has a local data acquisition module (from now on, called sta-tion), which performs the conditioning and digitalizing of the raw analogue signals acquired from the sensors.
The digitalized signals of every sub-station, then are forwarded to the main station that performs the following main tasks:
• Pre-processing of the data including
o Scaling
o Averaging, filtering
o Basic comparisons, and limit-monitoring
The interconnection between the stations are highly reliable industrial digital communication protocol – EtherCAT. EtherCAT (Ethernet for Control Automation Technology) is an open, real-time Ethernet-based real-time system. Its attractive characteristics make it suitable for automation applications.
• Data transfer: Ethernet/EtherCAT cable (min. CAT 5), shielded
• Distance between stations: 100 m (100BASE-TX)
• Data transfer rates: 100 Mbaud
• Delay: approx. 1 µs
In order to avoid on-site data representation and any other graphical user interface, an architecture version was implemented finally the concept of which is a headless architecture, with no dedicated local display. The main station therefore on one hand acts as a sub-station as it is able to acquire signals from the analogue sensors, on the other hand it serves as an endpoint of the EtherCAT network and a gateway to the remote server via Ethernet.
Control system components
The used PLC components are designed for industrial environments and conform the following regula-tions:
• Vibration/shock resistance: EN 60068-2-6/EN 60068-2-27
• EMC immunity/emission: conforms to EN 61000-6-2/EN 61000-6-4
• Protection class: IP 20
• Operating/storage temperature: -25...+60 °C/-40...+85 °C
• Relative humidity: 95 %, no condensation
Embedded PC
The local controller is an embedded PC. Thanks to their low power consumption (max. 3W) these devic-es are fanless. They are mounted to a DIN-rail, and have a compact size of 65 mm x 100 mm x 80 mm.
The core of the PC is a 32-bit ARM based CPU running with a 400 MHz clock. The operational memory is 64 MB RAM, and for local data storage a 256MB micro SD card is included by default. This can be ex-tended up to 4 GB.
The operating system is Microsoft Windows CE 6, and the control system is programmed to create a virtual Programmable Logic Controller.
In the absence of a monitor port, the operating system and its “virtual” display can only be accessed via the network, but covers most of the use cases.
In the event of a failure of the supply voltage, an integrated capacitive 1-second UPS provides sufficient energy for saving persistent data. It supports protocols such as real-time Ethernet, ADS UDP/TCP, Mod-bus TCP client/server or open TCP/IP-UDP/IP communication. The interfaces are: 1 x Ethernet 10/100 Mbit/s, 1 x USB device (behind the front flap), bus interface: 2 x RJ 45 (switched).
The analog input terminal processes single-ended signals in the range between 4 and 20 mA. The cur-rent is digitised to a resolution of 12 bits and is transmitted (electrically isolated) to the higher-level automation device. The EtherCAT Terminal combines eight channels in one housing. The measuring error is less than ±3% (relative to full scale value).
The input filter limit frequency is 1 kHz, and the default analogue-digital conversion time is 1.25 ms, which is more than needed in an application with so long time constants such as oil-condition monitor-ing.
The signal state of the EtherCAT Terminal is indicated by light emitting diodes. The error LEDs indicate an overload condition and a broken wire. The module also features built-in limit value monitoring.
The EtherCAT extension is connected to the end of the EtherCAT Terminal block. The terminal offers the option of connecting an Ethernet cable with RJ 45 connector, thereby extending the EtherCAT strand electrically isolated by up to 100 m. In the EtherCAT extension terminal, the E-bus signals are converted on the fly to Ethernet signal representation. Power supply to the EtherCAT extension electronics is via the E-bus.
The EtherCAT coupler acts as gateway between the EtherCAT fieldbus system and the connected Ether-CAT analog input terminal. The coupler converts the passing telegrams from EtherCAT to E-bus signal representation. The coupler is connected to the network via the upper Ethernet interface. The lower RJ 45 socket is used to connect further EtherCAT devices in the same strand.
The EtherCAT coupler needs external power supply since this module provides power to the other ones via the E-bus.
The Main station holds a PLC setup with the next modules:
• Embedded PC
• 8-channel analog (4-20 mA) terminal
• EtherCAT extension
Every station is equipped with its own power supply converting the mains 230 Vac to 24 V (1.5 A). The power supply circuit is protected with circuit breakers and fuses.
For easy installation, the input wires are bundled on a terminal block.
The housing is an IP 67 protected metal enclosure, the incoming and outgoing wires are placed in glands.
The sub-station includes a PLC setup with the next modules:
• EtherCAT coupler
• 8-channel analog (4-20 mA) terminal
• End terminal
Every station is equipped with its own power supply converting the mains 230 Vac to 24 V (1.5 A). The power supply circuit is protected with circuit breakers and fuses.
For easy installation, the input wires are bundled on a terminal block.
The housing is an IP 67 protected plastic enclosure with transparent cover, the incoming and outgoing wires are placed in glands.
The firmware of the DAQ hardware developed by ATEKNEA is responsible for receiving the data gener-ated by the applied sensors. The final version of the sub-stations are capable of detecting eight 4-20 mA channels in parallel with continuous or pulsed mode operation. The protocol of the pulsed mode signal was developed in cooperation with AC²T.
In December 2014, the preliminary field tests were started at the premises of BKG and RYTEC. During the first tests, the first version of the data acquisition software showed limitations. Therefore, Data Acquisition program running on the PLC was developed continuously based on the experiences gained through the pilots in Güssing and Frankfurt from the end of year 2014.
The initial version was ready to process 8 analog channels simultaneously, out of which one (dedicated channel-8) can operate in the pulse mode. At first run (after reset or power-up), the program waited for 30 seconds. If within this time frame the value of channel-8 rose to 20 mA, the program switched to pulse mode, expecting sequential output on channel-8. The PC based visualization program was told to be reported in this deliverable, however since then, other further development guidelines have been considered, namely it was foreseen that the sensors will be operated in pulse mode (including the cor-rosion and multi-sensors as well) in the future in order to minimize the required analog ports. There-fore, the following features have been implemented to enhance modularity and scalability:
• All 8 analog channels will be ready for pulse mode acquisition
• Local HMI visualization for setting up the PLC module
• Prepare the trending code for the visualization of 8x6 parameters
Major improvement was the implementation of a scalable and flexible code enabling easy scale-up of the data acquisition system by adding or replacing sub-stations or sensors.
Data structure
The total number of the measured data per plant is determined by 3 parameters: the number of stations (Güssing: 1, Frankfurt: up to 5), the number of analog channels available (8 per stations considering the currently used PLC modules), and the pulse count in pulsed mode (assumed to be less than 10). The in-put channels and the measured data are therefore stored in dynamically sized multi-dimensional arrays determined by these constants, which can be easily re-configured before installation.
Program
The main program consists of 3 parts:
• Data acquisition (or data generation for simulation in debug mode):
Calls ReadChannel function block for each input channels, converts the ADC values to 4-20 mA current value.
In debug mode, random values are generated.
• Main state machine
Handles sampling timer and prepares messages to be sent or entires to be logged based on the polled measured data of one station
• Communication
Sends the latest measured values or saves them to disk.
WP4 – DAQ software and GUI
Methodology
The purpose of this component is to manage the measured data received from the PLC and to provide configuration and visualization possibilities for end users. The component can be broken down into three main components:
• Condimon database in which measurement and configuration data is stored
• CondimonDaemon that collects and saves measurement data into the database
• CondimonGUI that provides visualization, parameter configuration user interface and handles measurements
In the current configuration all of these components run on the same host.
The relations between the three main software components are depicted below. All of the components run in a separate process. Both CondimonGUI and CondimonDaemon have access to the database: CondimonDaemon continuously saves the measured values, sent by the PLC, into the database; Con-dimonGUI can display the measured data in different views.
Applied technologies and hosting environment
The application uses the MySQL database engine as it is free, available on multiple platforms and suitable for the data quantity the Condimon system produces.
CondimonDaemon and CondimonGUI are implemented in Java (Java 1.6) because the Java platform supports both server and client applications well, furthermore it is platform independent so the Condimon system can be easily migrated to other platforms, for instance Microsoft Windows, on demand. For database connectivity the Java Database Connectivity (JDBC) library, provided by MySQL, is used.
The application was developed in the Eclipse Integrated Development Environment and consists of the following four Eclipse projects:
• CondimonCommon: Common functionalities for CondimonDaemon and CondimonGUI
• CondimonDaemon: The implementation of the CondimonDaemon backround process
• CondimonGUI: The implementation of the CondimonGUI application
• DatabaseTools: Classes for database connectivity and database operations
The platform of this component is hosted on a low energy consumption Shuttle PC running Lubuntu 14.10 operating system, which is designed for these kind of hardware types. The necessary environment has been set up via custom bash scripts for different purposes, such as installation, process monitoring and automatic start-up.
Condimon application components can be installed by executing the installation script created for Condimon. This script creates the necessary folders, copies the necessary files, sets the correct file permissions and registers CondimonDaemon as a standard Linux service thus ensuring that the CondimonDaemon data logger module is automatically started when the operating system starts.
The database structure and classes are detailed in D4.2 here we present the main features of the user interface.
1) Monitor view
This view is the default when the application starts.
In this view the desired parameters can be monitored for a given station and channel for the active measurement. The desired station and channel can be selected via the comboboxes in the upper right corner of the CondimonGUI window. The user can select which parameters to monitor by enabling/disabling the checkboxes next to the configured parameter names. The monitored parameters are displayed in different colors on the chart.
It is possible to select the timeframe of the measurement. By pressing the OK button, the new timeframe is applied.
When the monitored parameter value is above or below the configured threshold, the background of the corresponding parameter name turns red.
This view is the default when the application starts.
In this view the desired parameters can be monitored for a given station and channel for the active measurement. The desired station and channel can be selected via the comboboxes in the upper right corner of the CondimonGUI window. The user can select which parameters to monitor by enabling/disabling the checkboxes next to the configured parameter names. The monitored parameters are displayed in different colors on the chart.
It is possible to select the timeframe of the measurement. By pressing the OK button, the new timeframe is applied.
When the monitored parameter value is above or below the configured threshold, the background of the corresponding parameter name turns red.
2) History view
In this view the user can examine every measurement in the database. Selecting station-channel pair and parameters works the same way as in the Monitor view.
Under the parameter names the desired measurement can be selected by its start date. By default, the currently active measurement is loaded. When a measurement is selected, the whole timeframe of the measurement is displayed for the selected parameters. It is possible to select a smaller timeframe by setting the Start date and the End date fields.
By double clicking on a value on the chart, the value is displayed in the bottom left corner of the window.
3) Export database
In this view the measured data along with all the configurations can be exported in a mysql specific format. It is possible to select a date range in which the measured data will be exported.
If the user presses Cancel, the view is changed back to the Monitor view.
If the user presses Export, a dialog appears where the filename for the database file can be set. It is recommended to use the .sql extension for the database file. This file can only be imported by system administrators using MySQL-specific tools.
4) Import from CSV
It is possible to import CSV files to the database, but only files generated by the Condimon system are supported. If the user selects Import from CSV menu item from the Tools menu, a dialog pops up in which it is possible to select a CSV file. After selecting a file and pressing Open, the import process is started. Upon it is finished, the user is notified about the result.
Remote accessibility
On the test sites a Shuttle computer was installed and configured with LUbuntu 14.10 operating system with all the necessary software modules as well.
Both the data logging back-end application and the Condimon GUI were set up on the Shuttle. Condimon GUI is responsible for data visualization where the logged measurement data can be shown on different charts.
An isolated local computer network was created on the test field for Condimon devices (PLC and Shuttle) since their communication interface is based on TCP/IP protocol. This local network is controlled by a router device. On the test field an IP router was used with DD-WRT firmware and connected to the internet via wired connection.
The Condimon GUI application can be launched directly on the Shuttle’s local display however it is also possible to use a remote desktop connection (VNC) from another computer which is attached to the local network. When a VNC server is operating it is possible to use this computer’s local desktop environment from a remote device via a VNC client.
WP5 – Knowledge base and evaluation algorithm
The main objective of WP5 was to collect and analyse oil samples in laboratory to compare the results with the sensor system measurements. This way, valuable input was provided for the software development and to set up the knowledge base for correct signal interpretation.
Oil data evaluation and gas engine product range
Oil analyses from in-service gas engine oils were evaluated to get knowledge about the oil degradation process. A market research of available gas engine oils provided the range of products. Selected gas engines oils were evaluated in different artificial alteration methods including online sensor systems. Thereby, generated sensor results were compared to the laboratory analytical data to setup the knowledge base for proper signal interpretation. Results from field test were included.
The oil data interpreted showed that mostly TBN and or TAN limits were reached. In nearly two out of three samples at least the limit for TBN or TAN was reached.
Accordingly, TBN or TAN were selected as the critical parameters, and a comparison between these parameters was done. Principally, several operating paths could be possible to reach one of the limits. By decrease of TBN due to consumption of base reserve and without significant increase of the TAN, the limit of the TBN is reached first. Other way round, by generating acids during operating which could not be sufficiently neutralized by base reserve (TBN), TAN will be significantly increased with only minor consumption of TBN. In this case, the limit for the TAN will reached first.
Generally, a wide range of different operation paths at the TBN consumption is noticeable. Exemplarily for one selected gas engine oil, the limit was already reached after around 350 operating hours. For another oil change interval, the TBN limit was not reached even after 700 h. This behaviour can be due to different operating conditions during the operation of the engine. Thereby, changes of the gas compositions are supposed as the most relevant reason for these differences.
Summarizing, it can be said that due to different operating conditions – most probably due to changes in the gas composition – provoke different alteration behaviour of the lubricant. Therefore, a good oil condition monitoring is necessary for optimizing the use of oil. Application of the CONDIMON multi-sensor system is hence fully justified as the means for online lubricant monitoring.
Sensor evaluation by artificial oil alteration
Artificial alteration means applying elevated stress conditions to the oil sample to accelerate oil degradation in a short-term scale. Nevertheless, an artificial alteration procedure should remain as close to reality as possible. This way, the quality of lubricants under special operating conditions and the usefulness of sensor systems for special applications can be investigated without the need to perform time-consuming and expensive field tests.
Currently used standardized methods for the artificial alteration of engine oils evaluate different parameters of the oil performance. Most standards examine the thermal-oxidative stability of oils by exposing the lubricant to elevated temperatures and oxygen from air e.g. ASTM D4871 (Standard Guide for Universal Oxidation/Thermal Stability Test Apparatus) or DIN 51352 (determination of ageing characteristics of lubricating oils).
Based on the existing methods, an adapted alteration method was used to specially simulate oil life cycles in gas engines. Therefore, the lubricant was deteriorated at elevated temperature in a defined vessel able to blow gas into the oil. Additionally, a fixation was used to implement the proposed Condimon sensor system in the artificial alteration device.
In order to simulate the impact of different fuel qualities on lubricant degradation, two different alteration methods were chosen. In the first method, only air was blown through the lubricant. This method denoted with “air” should simulate mild conditions in an engine, e.g. the operation with natural gas almost free from contaminants that could form aggressive compounds. The conditions for the second method called “biogas” were based on the “air” method and adjusted to simulate the impact of biogas on accelerated oil degradation.
Also different sensor system were integrated to the sensor bypass: corrosion sensor, Condimon Multi Sensor (CMS) and a commercial oil condition sensor possible to measure conductivity, rel. permittivity, rel. humidity and temperature. As sacrificial layer for the corrosion sensor, lead was chosen for all these experiments.
In order to follow the oil degradation during the artificial alteration, oil samples were taken on a regular base. The oil condition was analysed in the laboratory expressed by the total base number TBN according to DIN ISO 3771, neutralization number NN according to DIN 51558 as well as oxidation according to DIN 51453.
The behaviour of the oils during artificial alteration are discussed by means of laboratory analyses. It was clearly demonstrated that TBN degrades much faster with the method “biogas” than with the method “air” for every oil. Similar tendencies can be seen by looking at the trends of the neutralization umber NN. Thereby, also a higher increase at the method “biogas” in comparison to the method “air” can be seen.
The trends of the conductivity were recorded during the artificial alterations. Thereby, mainly the typical bathtub curve could be observed: the conductivity of a liquid such as oil is given by the concentration of movable charge carriers. The conductivity of the fresh fluid is mainly given by the formulation of the additives and decreases in the beginning. After this, a period with more or less stable conductivity can be seen. If the built up of alteration products becomes dominant, the conductivity began to raise. This point is an indicator that the oil reaches the end of the lifetime.
When investigating permittivity values it can be seen that the starting point for the permittivity is not so much varying in comparison to the conductivity. The starting point for the evaluated fresh oils is between 2.1 and 2.3 which is a typical range for mineral oils. A closer look at the permittivity curves revealed that the permittivity trends showed a linear increase when recorded with the Condimon Multi Sensor and curves showing a bathtub trend were observed with the commercial oil condition sensor. The findings suggest that the measurements of the permittivity with the commercial oil condition sensor were influenced by the changes in the conductivity.
As the developed Condimon Multi Sensor shows the typical linear increase over the alteration time it can be concluded that this sensor has no significant influence of the conductivity for the desired gas engine oil which makes the sensor very suitable to monitor these fluids.
As to the corrosion sensor, the corrosion process starts at a certain alteration time (equivalent with a certain oil condition) showing a sharp response characteristic. At some artificial alterations, no corrosive attack of the sacrificial layer could be observed. This could be attributed to the fact that the oil was not corrosive against lead till the end of the experiment.
Special events like the simulation of a downtime period by stopping the alteration of the addition of a fresh oil were performed. It was found out that during the period where the alteration was stopped (= downtime period) no significant change of the sensor signals could be observed. As the alteration starts again, the signals (conductivity and permittivity) proceed the trend as before the simulated downtime period. As the oil was not corrosive against lead before the alteration was stopped also no significant change occurred during the downtime period – as expected. But shortly after the alteration was started again, the oil became corrosive to the lead lowering the signal for the remaining area.
Another special event referred to the addition of fresh oil. After a noticeable signal change of the corrosion sensor was observed, a certain amount of fresh oil (~ 25 %) was added to the artificial alteration. This addition of fresh oil stopped the corrosion process of the sacrificial layer immediately. By further alteration and hence oil degradation, the corrosion process started again as the critical point of acidification was reached again. This experiment confirms the behaviour of the corrosions sensor to be sensitive to a critical amount of acidification in the lubricant.
Sensor signal interpretation – algorithm
The comparison between the sensor signals and the laboratory analyses revealed that no general correlations were given. In-depth analysis revealed that the relationships were strongly depending on the oil formulation and the alteration behaviour in the desired application.
The evaluation of the trends of the conductivity showed that the oil limits were reached for oils providing the typical bathtub curve shortly after the increasing phase was started. Therefore, it is very important to analyse the complete trend of the conductivity to find the individual stages and consequently the condition of the oil.
The rel. permittivity showed a good correlation to the neutralization number of the oil. Thereby, correlations for the method “air” and “biogas” could be found widely independent from the oil type. As typical threshold, an increase of about 2 to 3 % increases of the rel. permittivity could be identified.
The signal of the corrosion sensor showed that at a certain amount of acidification the corrosion process started. This initial point for corrosion was also dependent on the oil formulation. Mostly, the initial point for onset of corrosion was at an increase of the NN in the range from 1 to 2 mg KOG/g giving a clear warning signal for the operator.
WP6 – Field tests
The field tests were performed at two locations: at project partner BKG in Güssing (Austria) and at pro-ject partner RYTEC in Frankfurt am Main (Germany). The evaluation of the CONDIMON sensor system was carried out in three stages: 1) laboratory work at AC²T and at ATEKNEA was carried out continuous-ly along with the development process. 2) at AC²T, an artificial alteration equipment was set up and used for the CONDIMON sensor system benchmarked against commercial sensors. 3) at ATEKNEA, the data acquisition modules and interfaces were tested by means of a signal emulator customized for the CONDIMON DAQ system.
After all the components were successfully evaluated and validated, preliminary field tests using the first prototypes of the CONDIMON sensor system were started in December 2014. The tests revealed input to further optimisation based on collection of useful real environment data from both plants. Based on this experience, AC²T and ATEKNEA further developed the system (see details in previous work packages) and the installed modules were substituted by the updated versions progressively. In July 2015, the final prototype of the CONDIMON multi-parameter sensor (CMS) was integrated and installed in both the biogas plants and AC²T laboratory for evaluation.
Currently, two Condimon sensor systems are operated at Rytec and one at BKG.
Preliminary field tests
The first sensors were installed by AC²T in December 2014. Thereby, a prototype of the developed cor-rosion sensor with lead as sacrificial layer was mounted into the engine. This sensor delivers signals of the remaining area of the sensing element as well as the temperature. Furthermore, a commercial oil condition sensor was also implemented into the engine.
The sensor signals (4-20 mA) were connected to the Programmable Logic Controller (PLC) as described in WP3. The PLC was connected to a shuttle PC as described in WP4.
Based on the first experiences, the following modifications were made:
• Software bugs have been corrected.
• System is able to receive signals from
o 8 analogue 4-20mA channels OR
o 7 analogue 4-20mA channels + one pulse mode channel (dedicated to channel-8).
The new firmware upgrade was installed at BKG by ATEKNEA in March 2015.
The capacitance values of the corrosion sensor showed the degradation of the sacrificial layer. During a downtime period of 7 days in April 2015, the signals of the corrosion sensors remain almost stable. This demonstrates that the corrosion process was interrupted or took place only on a very low level, respectively. After starting the engine again and reaching the temperature at the common operating conditions, the corrosion process proceeded as expected.
The same system was installed at RYTEC in April 2015. Under the operating conditions, the commercial oil condition sensor failed while the CONDIMON sensor system turned out to provide stable and reliable sensor data.
CONDIMON network settings
A small server computer was used for data logging and visualization at both sites. On the test sites, a Shuttle computer was installed and configured with all the necessary software modules as well (including MySQL database, Java JRE, etc.).
Both the data logging back-end application and the Condimon GUI were set up on the Shuttle. Condimon GUI is responsible for data visualization where the logged measurement data can be shown on different charts.
An isolated local computer network was created on the test field for Condimon devices (PLC and Shuttle) since their communication interface is based on TCP/IP protocol. This local network is controlled by a router device. On the test field, a router was used to connect to the internet via wired connection.
The Shuttle computer and the PLC were attached to the local network and a static IP address was assigned to them.
After the network connection between the PLC and the Shuttle had been established, the data logging service was started. Considering the fact that the PLC sends raw current (mA) values, these values should be recalculated based on the type of the given input. From the Condimon GUI application calculation coefficients can be configured for each stations and channels.
The final version of the sensors presented in the description of WP2 and the upgraded DAQ (WP3 and WP4) system were installed in July 2015. The measurements have been running since then and the measurement data is downloaded by the method descried later in this document.
The measurement signals show good accordance with the laboratory analysis. Here, a short summary of the signal analysis is presented.
CONDIMON Multi Sensor evaluation by field tests
Hereby, only the most important findings are highlighted:
Conductivity: The trend of the temperature compensated conductivity showed a steady increase in all observed periods. By looking at the oil analyses from the laboratory, an oil degradation can be noticed (decrease of TBN and increase of NN and oxidation).
Permittivity: by proper calibration of the permittivity sensor against temperature, the signal shows a steady increase of the rel. permittivity thus proving the effectiveness of the compensation of the electronic temperature effects.
Corrosion: the laboratory analyses confirm the immediate attack of the sacrificial layer as the limit for the NN was already reached.
The results from the field test and in-service gas engine oils largely confirmed the relationship between the sensor signals and the laboratory analyses. So, the most important objective of the CONDIMON project was achieved. Besides, the final CONDIMON multi-parameter sensor (CMS) became an attractive pre-marker prototype.
We can claim that both the final CMS sensor and the flexible data acquisition system is ahead of the current state-of-the-art, so the exploitation of the CONDIMON system has high market potential.
Potential Impact:
Potential impacts and socio-economic effects of the project:
Biogas production has significantly risen across the EU in the past years. According to the statistics of the European Biogas Association today there are more than 13 800 biogas plants in Europe with an installed gross capacity of 7400 Megawatt. By 2020 methane production will expectedly double compared to a decade ago and reach 24.2 billion m3. Growth tendencies are supported by the strong commitment of the EU policy makers to ease energy dependency and increase the share of renewable energy sources in the gross final energy consumption to 20% by 2020 in which biogas has a key importance.
However process optimisation through innovative technologies still has much potential to increase the productivity and profitability of existing and newly established biogas plants. Currently biogas engine operators often suffer from high costs associated with maintenance due to the special chemical attack on the engine and engine oil resulting from biogas process. Quality degradation in oil can attack essential engine parts leading to increased wear and corrosive wear which cause early failure of the machine. Despite much scientific research and patents proposing oil quality sensor approaches for certain parameters, currently there are no commercially available sensor systems measuring all key parameters of oil quality needed to reliably determine the necessity of oil maintenance.
The CONDIMON integrated sensor system for in-line oil condition monitoring covers the measurement of the most important oil condition parameters. The sensor system incorporates OEM sensors of permittivity, conductivity, viscosity, temperature and moisture content as well as a novel corrosion sensor. This unique sensor can directly measure the corrosion (acidification) of the lubricant, which is a critical parameter in combustion engines, especially in case of biofuel based operations. The Condimon sensor system is able to ensure the protection of the machine by online monitoring of the lubricant, while allowing the optimization of the oil change interval. The use of this technology leads to reduced maintenance costs and offers good potentials to increase profitability and competitiveness of the 13.800 currently operating biogas plants in Europe.
On the other hand, the socio-economic impacts of the project has to be mentioned: Environmental sustainability plays a critical role if we focus on socio-economic impact. The members of the consortium have investigated the possible impacts which could be experienced after the product takes its way on the market. The first possible and directly measurable impact could be achieved by the local retailer community. Obviously, training is crucial before the retailers could sell the product successfully. During the training activity, the knowledge of the retailers is growing about a technology, which lowers both the operation costs and the amount of the emission by the end users’ facilities. In parallel, the global aim of the EU is to constantly lower the emission , and the opportunity to fulfil these recommendations with a side effect of lowering costs will have an effect on sales motivation by the retailers. Therefore, the increase of income from sales is expected by the retailers, while lower operation costs and a possible decrease on the amount of emission by the end users could be achieved. These factors together will build up the CONDIMON system’s socio-economic impact results chain:
By the retailer: Retailer training spend -->Retailer trained-->Sales improvement-->Income increase
By the end user: New technology spend-->technology applied-->Decrease on operation costs and on environmental pollution-->Competitiveness increases
The main dissemination activities:
The consortium has prepared a detailed plan for dissemination which supported the effective promotion of the CONDIMON system. In execution of dissemination activities the Management Board oversaw and enforce that the rules set by Annex II. II.30. of the Grant Agreement and the Consortium Agreement are respected. In order to ensure confidentiality in exploiting and protecting the results new information on the Foreground were not published without the previous approval of the consortium members. The coordinator in cooperation with the Exploitation Manager ensured that the Management Board has all information necessary on time for decision making as indicated by the terms and condition. Based on the key aspects of dissemination established, the consortium has completed a number of promotion activities. For dissemination possibilities, a wide range of project relevant websites, presentations, seminars, information leaflets, newsletter have been examined through means of Internet, phone, personal contact press release etc. The consortium members, especially SME partners have decided to play an active role in project dissemination activities ensuring that no non-confidential information is published which would negatively affect the exploitation of the research results generated in the frame of the project. The results are described in light of the targeted audience. Images, screenshots and further materials emerged during project dissemination activities.
Exploitation of results:
While constructing viable financial models for the exploitation of Condimon, partners agreed that the largest volume of sales can be expected in Europe. This standpoint was partly based on the fact that the continent is the largest market inevitably leads biogas development, production and consumption and also on the in-depth knowledge, experience and current clientele that partners already have in this territory. This is also backed by discussions at the STLE 2015, although vital interest in commercialisation of the Condimon system outside Europe was expressed and important gas engine producers are located in the USA, e.g. Cummins, Waukesha. Thus, the regional biogas market was investigated in detail to explore the recent trends and explore the potentials for Condimon on the market.
In Europe, the largest boom in biogas installations were experienced between 2011 and 2012 with circa 1400 new operation sites. Over 70% of the new projects were based in Germany which is the strongest market in Europe with over 8700 biogas producing plants (in 2014). However, due to the revised feed-in tariffs in the past two years, the market in Germany has experienced a slowdown compared to the years of boost with around 340 installations in 2012 and expected 200 annual new projects so forth. The potential impact of the limits introduced on state support for feeding biogas produced electricity into the grid will expectedly push demands for further cost optimisation on both installed and newly established plants including economic maintenance solutions and technologies such as Condimon that help reducing operating expenses.
In terms of market position, the second strongest in Europe is Italy with 1,264 and Switzerland with 606 anaerobic digesters. According to the European Biogas Association, significant growth is expected in France, Denmark and in the UK partly due to the favourable policy decisions for biogas support in the next years. In France for example, the number of new installations is expected to reach 500 under the new energy bill introduced this year. While in Denmark the increase of feed-in tariffs and the endorsement of the 50% manure treatment target are inducing market growth. In the UK, biogas potential is greatly supported by the new Renewable Heat Incentive (RHI) that took off in May 2014 enabling higher feed-in tariffs for biogas from anaerobic digesters of all scale. On the general level, the European biogas production can expect a boost from the new end-of-waste criteria (EoW) recommendations that will expectedly lead to the legislative support for the utilisation of digestate the by-product of biogas production. The following tables depict in details the structure and production capacity of the European biogas industry.
List of Websites:
www.condimon.eu
Biomass coming from biological material such as manure, organic waste, trees and plants is one of the largest and most important renewable energy options at present. Biogas production has significantly risen across the EU in the past years. According to the statistics of the European Biogas Association today there are more than 13 800 biogas plants in Europe with an installed gross capacity of 7400 Megawatt. By 2020 methane production will expectedly double compared to a decade ago and reach 24.2 billion cubic meter.
However, process optimisation through innovative technologies still has much potential to increase the productivity and profitability of existing and newly established biogas plants. For example biogas operations often suffer from high costs associated with quality degradation of oil that can attack essential engine parts. As oil analysis can give a reliable overview of the current condition of the engine it can be considered as an essential aspect of optimally operating industrial engines.
The main objective of the CONDIMON project was to create a validated prototype of a multisensory system suitable for the online monitoring of the lubricant oil of biogas generators running at the facilities of project partners. The prototype incorporates a novel sensor that can directly measure the corrosion (acidification) of the lubricant, a critical parameter in combustion engines especially in case of biofuel based operations. Our main objective was to create an efficient condition monitoring system that returns the investment within two years for existing installations and can be seamlessly integrated into new biogas based electric generators.
The CONDIMON multi-parameter oil lubricant monitoring system was installed, validated and long-term tested at the biogas plants of two consortium members, RYTEC (Germany) and BKG (Austria). During the development process we always took in mind to achieve a prototype that is as close to market entry as possible. Thus, we concluded with fully integrated sensor bodies and DAQ system that require minimal modifications before turning into a marketable product.
We also developed an extensive knowledge base of oil lubricant data that is unique among competitors. This work is based on one and a half year of measurements in laboratory, using artificial alteration, and real environment data gathered from consortium members BKG and RYTEC. This enables us to give both the raw physical parameters of the oil lubricant, like competitors do, and – as unique selling point – to interpret the data suited to the end-user expectations and to give decision support.
Based on the results of the project, we claim that CONDIMON system lowers operation costs, thus contributes to the competitiveness of biogas sector SMEs. The number of biogas farms in Europe is estimated to more than 15 000 of which approx. 6 500 are farm scale plants, with more than 1 000 new installations each year, based on the last 3 years growth statistics.
Project Context and Objectives:
Farm-scale biogas plants are making their way on meeting the requirements on the use of biomass set by 2020 however their operation still strongly depends on subsidies. There is still a huge potential to optimize operational processes thus financial profitability in the EU-27. The aim of CMMS, UNICOMP, BKG, MAZZY and RYTEC was to develop an innovative online condition monitoring system which would allow cost-effective and safe operation.
The biogas sector has seen a rapid development in recent years and continues to grow. For farm, small and middle scale power plants, biomass is usually utilized by digestion to biogas as fuel for co-generation engines (electricity + heat).
This kind of energy production is typically performed by SMEs such as like RYTEC and BKG, utilizing the biogas in combined power units consisting of a generator and an internal combustion engine, which was the target market for the CONDIMON project, providing potential benefit for a large number of SMEs.
However, bio-gas engine operators suffer from high costs associated with maintenance due to the special chemical attack on the engine and engine oil resulting from biogas operation. This adds to the fact that biogas based power generation is still not competitive with other (also renewable) energy sources and highly relies on governmental subsidies. Oil analysis gives a reliable overview of the current condition of the engine as it can be considered the “lifeblood of industrial engines” as declared by CMMS, leading global provider of oil monitoring and testing solutions.
Beside oxidative degradation, the main oil change criteria in farm scale biogas engines are the acidity and water content (relative humidity). Compared to conventional fuels, bio-fuelled engines are more severely exposed to acidification of the lubricating oil and humidity increase. This results from the fact that bio-fuels often contain significantly higher amounts of chemically aggressive elements building aggressive acidic compounds during combustion and thus contaminating the oil. On the other hand, water increases the oxidation rate of the oil that attacks the base stock and additives, and decreases its load bearing capability. This is especially the case for biogas obtained from agricultural waste or animal mature (as typical for farm-scale biogas plants) and that in spite of costly gas-cleaning efforts. High-end gas cleaning equipment is not economical for farm scale biogas plants (SMEs), only for large-scale biogas plants, but even there the acidification (which is linked to the corrosiveness) and humidity of the oil remains a major issue.
These facts highlight the need for online monitoring of oil quality both for economic and ecological considerations. Quality degradation in oil can attack essential engine parts leading to increased wear and corrosive wear and to early failing of the machine. Although there is much scientific research and patents proposing oil quality sensor approaches for certain parameters, there are currently no commercially available sensor systems measuring all key parameters of oil quality necessary to determine reliably the necessity of oil maintenance.
The concept of CONDIMON
The CONDIMON system is based on online monitoring of oil quality in biogas engines by means of a multi-parameter sensor system and evaluation software based on a knowledge base for best practice in maintenance.
CONDIMON combines 5 sensors for the measurement of conductivity, rel. permittivity, rel. humidity, corrosion and temperature. By means of these sensors the level of oil deterioration can be monitored.
The knowledge base was created applying the numerous input data generated during the field tests and laboratory analysis using artificial alteration and contains an algorithm to provide trends in oil quality to easily interpret the indication of an oil change.
The system provides industrial compatibility for additional sensor extension by industrial standard interfaces and bus systems to meet special needs.
Innovation
Beside the integration and combined evaluation of multiple state-of-the-art online oil condition sensor types, the CONDIMON system includes a novel corrosion sensor that provides indication about the oil’s degree of degradation mainly expressed as acidity, by determining the actual rate of corrosion. In bio-gas fuelled engines, increased acidity is one of the crucial oil change criteria and root causes of lubricant degradation and machine failures.
The proposed multi-parameter system is supplemented with a knowledge base and an expert system for signal evaluation in order to:
• safely extend the oil changes interval by 25% (expected in average), while
• preventing any unexpected engine damage by early detection of adverse conditions.
Among others, it was also a goal of this project to provide a significantly simplified indication of oil condition to the end user based on the development of a knowledge base for integrated signal evaluation.
The highly innovative corrosion sensing concept used for acidity measurement is based on the contactless measurement of the remaining metallic volume of a sacrificial layer exposed to corrosion. There is a strong correlation between the oil’s corrosiveness and the acid content based on the research carried out by AC²T in the recent years, during which the basis of this new measurement method was established. Now, in this project the results of laboratory experiments were utilized to develop a novel industrial grade sensor as a part of the proposed multi-parameter sensor system.
The proposers of the CONDIMON technology recognized the potential business opportunity to develop a low-cost technology for the monitoring of oil quality in biogas driven engines, which is an emerging market due to the need for CO2 neutral energy in Europe.
The CONDIMON product will be sold on newly installed biogas plants and for retrofitting existing engines by RYTEC. MAZZY will provide the data acquisition and evaluation software packages while UNICOMP will produce the multisensory sensor module and the data acquisition hardware in line with the contract volumes. RYTEC installs the system at customer’s site and as a first selling point distributes the profit to partners by their respective shares based on the production. The profit for RYTEC is established by the cost of installation. UNICOMP is considered to provide the disposable oil corrosion sensing elements (estimated 10 pieces per year per installations) that are needed for the operation of the sold systems and benefits from the corresponding profits.
Scientific and Technological Objectives:
• Scientific objectives:
• To provide optimized technical specifications for the corrosion sensor industrialization in point of robustness, compatibility and maintenance.
• To provide algorithm of the signal evaluation of the multisensory environment.
• To create a knowledge base for the evaluation of the multisensory system signals to provide an easy-to-interpret indication for the end-user, including correlations to standard parameters.
• Technological and application related objectives:
• To design a sensor body withstanding operating temperatures referring to oil temperatures up to 120°C, oil pressures of 10 bar and vibrations; but allowing an easy ex-post upgrade to existing engines as well as an easy replacement of the sensing element of the corrosion sensor.
• To deliver a disposable sensing element, replaceable at the time of oil change maintenance.
• To deliver a prototype integrating all components and the evaluation software.
• To validate the system in field tests at least 3 end users utilizing different biogas types and to investigate correlations to conventional oil analysis as base for standardization.
• To develop signal evaluation software implementing the developed knowledge base and evaluation algorithm to enable an easy-to-interpret indication.
• To prepare the prototype for commercialization during the project.
• Market related objectives:
• To achieve a market price for the multi-sensor system in the medium to upper price range of commercial sensor systems with widely comparable features, and a market price for the disposable sensing element significantly below costs for lubricant analysis.
• To effectively demonstrate the CONDIMON system in field-tests for dissemination at the demonstration plants provided by BKG and RYTEC.
• Training, dissemination and exploitation objectives:
• To manage the foreground knowledge, as well as to protect and to use the results to the best advantage of the SME proposers.
• To perform training and dissemination activities, and to ensure that SME participants will be able to assimilate the results by working out an appropriate exploitation strategy.
• To provide a methodology as a tool for the technical SMEs enabling them to “adopt and adapt” the CONDIMON system (i.e. evaluation algorithms) to engine systems with other fuel types in the post project phase ensuring better exploitation of the results
Project Results:
The objectives were achieved by carrying out the following development tasks in the frame of the CONDIMON project: existing know-how within the Consortium was compiled so that we could address the most up-to-date requirements and finalize our preliminary system specifications (WP1). During this task, we emphasized the marketing aspects, so that the prototype can be sold on market short after the execution of the project. Finally, we concluded with a system of fully integrated oil condition sensor with a flexible data acquisition hardware and software so that the system is capable of providing useful analysis data online.
Four R&D work packages were carried out in parallel in order to meet the defined system specifications. The novel corrosion sensor was further developed (WP2) so it can be integrated into the CONDIMON system. Besides, the sensor electronics of a compact multi-parameter sensor measuring rel. permittivity, conductivity, rel. humidity and temperature of the lubricant were developed.
The data acquisition (DAQ) hardware (WP3) was developed based on a custom PLC system in order to meet the requirements of harsh industrial environment. The central PLC unit is connected to the PC installed in the control rooms of biogas plants. The DAQ software (WP4) shows online data trends to the maintainers and provides data logging, warnings and system alarms adjusted to specific thresholds.
The knowledge base and the signal processing algorithm were developed in WP5. This development was based on the input data gathered from laboratory analyses based on artificial alteration and real-environment field tests carried out in Frankfurt (RYTEC) and Güssing (BKG).
Finally, in WP6 all the system parts developed in the first five work packages were integrated and installed for field tests. The field tests were running from month 12 until the end of the project at facilities of RYTEC and BKG. By the end of the project, the final CONDIMON system was validated and demonstrated in this work package.
In the following the most important results of these work packages are summarized.
WP1 – System specifications
The objectives targeted in the Condimon project were achieved by the development of a multi-parameter sensor system. The main blocks are the oil sensors, the interface electronics, the PLC based data acquisition and PC based signal processing, graphical user interface (GUI) and control unit. Following specifications are fulfilled by the current Condimon Sensor System:
General requirements
• IP protection: IP66
• Electrical power: 12-24V
• Communication interfaces of existing data loggers/controllers that the sensor system will be op-tionally connected to 4-20mA
• Environmental considerations regarding indoor/outdoor operation, temperature and humidity range, stability against vibration and impact
• Mechanical considerations regarding low weight, size, installation and others, e.g. precautions for implementation in existing gas engines
• Market price – target values
o Multi-sensor system in the medium to upper price range of commercial sensor systems with comparable features where possible
o Disposable sensing element significantly below costs for lubricant analysis
Sensors
• Type of sensors: Corrosion, rel. permittivity, conductivity, rel. humidity and temperature
• Operational pressure range: 0 to 10 bar
• Operational temperature limitations for the sensor body and the sensing element referring to oil temperature up to 120°C
Control system
• Hardware requirements
o Dual Ethernet connection
o Minimum XScale 500MHz processor
o Minimum 64M RAM
o Non-volatile memory for parameters
o Touch screen for local operations
o CF or USB slot for high capacity storage
• Interface requirements
o Profibus
o 4-20 mA
o Ethernet
Software requirements
The collected sensor data are stored and/or pre-processed locally. The software of the system should fulfil the needs listed below. The system also should provide a Human Machine Interface to enable the operator to quickly interference if necessary.
Key software features:
• Read and store the sensor data
• Pre-process option for the sensor data (average, integrate, maximum, minimum, etc.)
• Human Machine Interface for parameter optimization
• Relation to existing control systems, in particular Ethernet and 4-20mA
WP2 – Sensor development
Based on specific background of AC²T on the corrosion sensor and on the system specifications, the concept of the industrial design of the corrosion sensor was developed. Key element of the corrosion sensor is the sensing element with the sacrificial layer which is corroded by oil that contains corrosive compounds. As sacrificial material, lead was used as it corrodes by organic acids that are built up during the engine operation. The sensing element can be easily replaced on the sensor body. During engine operation, corrosion process on sensing element, i.e. value for the remaining area of the sacrificial layer, is monitored by contact-less readout electrodes. Measurement is done via frequency of a RC oscillator connected to a microcontroller. Further parts of the microcontroller are reading the temperature of the temperature sensor for compensation and giving the calculated value to the standardized output. According to the system specifications, the output is a current loop (4 - 20 mA).
Important part of the industrial corrosion sensor is a changeover device to enable the exchange of the sensing element at any time, in particular during operation.
According to the DoW, the concept of the corrosion sensor was combined with the other commercially available sensor types to provide the Condimon multi-parameter sensor. In the following, the details of the corrosion sensor and the multi-parameters sensor can be found.
Corrosion sensor
The key component of the corrosion sensor is the sacrificial layer in the sensing element. In the previous work of AC²T, lead as sacrificial layer showed good results as it is corroded by a defined amount of organic acids built up during the use of the oil. Therefore, lead as sacrificial layer was also used for the CONDIMON project.
Further task of the sensing element is to take up the structured readout electrodes and a sacrificial layer thus building a capacitor element. This sensing element is considered as a varying capacitance (vs acid content) and is measured by a custom capacitance measurement readout electronics. The main task of the readout electronics is the determination of the remaining area of the sacrificial layer. The remaining area can be well represented by the measurement of the capacitance between the readout electrodes.
In order to have a reliable measurement, the temperature is necessary for the compensation of temperature dependencies of the system. As the area for a temperature sensor is limited, a digital temperature sensor is used.
According to the specifications, 4 - 20 mA current outputs of the corrosion sensor are preferred. Therefore, the digital signals of the microcontroller have to be converted to analog ones. For this operation, a digital-analog converter (DAC) is needed which converts the signal to a defined current level.
It was also an important task to develop a reliable mechanism for fixing the sensing element in the protecting house. The design of the fixing system provides hold of the sensing element in the protecting house during storage and exchange of the sensing element. During operation, the sensing element is clamped between the sensor body and the protecting house to avoid that the sensing element falls out of the protection house.
Corrosion sensor performance
The developed corrosion sensor was first evaluated by means of artificial alteration, which is commonly used at AC²T for evaluation of sensor systems. The lubricants for this evaluation were gas engine oils that were degraded in the “hot” alteration zone of the alteration device by blowing air through the oil. The altered oil was transferred continuously to the “cold” sensor zone and backwards. Periodically taken oil samples were analysed in the laboratory to follow the oil condition of the degraded oil.
The entire CONDIMON sensor system was accordingly evaluated.
Among others, laboratory analyses included the measurement of the total base number (TBN) and neutralization number (NN). TBN indicates the amount of bases (base reserve) in an oil possible to neutralize acidic components taken up or formed upon lubricant alteration whereas NN refers to the amount of acidic components in an oil. A steady decrease of the TBN and steady increase of the NN can be observed. Common oil change criteria were applied. Typically, at a NN increase of about 1 mg KOH/g and a TBN decrease of about 2 mg KOH/g, respectively, the initial point for corrosion was reached.
Based on the findings achieved, some modifications of the sacrificial layer were performed to adapt the initial point for corrosion according to the oil, fuel and engine type.
CONDIMON multi-parameter sensor
In order to achieve the CONDIMON multi-parameter sensor, significant efforts from RTD partners (AC²T and ATEKNEA) were undertaken. Basically, the remaining sensors for conductivity, relative permittivity and relative humidity were integrated into the existing prototype of the corrosion sensor already equipped with a temperature sensor. The final setup is as follows:
For the measurement of the relative humidity of the lubricant, a capacitive humidity sensor element was used. This sensor is specially designed for measuring the oil humidity. Its small dimensions permitted an easy integration into the existing corrosion sensor setup.
For the measurement of the electrical conductivity and relative permittivity, a sensor element with similar dimension as for the relative humidity was used. This sensor element is a two electrode system with a comb structure. Furthermore, the sensor element has also integrated a PT1000 sensor for measurement of the oil temperature. Evaluation of the sensor element carried out by AC²T confirmed the possibility to measure the conductivity in the range needed for gas engine oils.
The integration of the sensing elements and the sensor electronics were carried out by AC²T and ATEKNEA. The sensors for relative humidity as well as conductivity and permittivity are installed into the sensor body of the corrosion sensor. For the standardized sensor output, also analog outputs 4-20mA were integrated.
A sine generator is used to apply an alternating voltage to the sensor elements (conductivity sensor element and humidity sensor element). The generated alternating voltage with defined frequency is applied to the sensor elements and the electrical current through the element is measured using an operational amplifier as trans-impedance amplifier. The output of the operational amplifier is proportional to the current and hence also to the conductance and capacitance, respectively.
Analog to digital and digital to analog conversions are carried out in a similar way as discussed for the corrosion sensor. All the parameters are available at the 4-20 mA output in pulsed mode with a sequence according to the protocol.
WP3 – DAQ hardware development
In this work package, the PLC based data acquisition hardware was developed by ATEKNEA. This sub-system has a two level hierarchy including data collector modules at the engines (sub-station) and a coordinator module (main station) in the control room of the plant. All the control electronics modules are based on industrial modules. In the following the main parts of the design is presented.
System topology
During the design of the system topology, the following characteristics of the targeted application fields were taken into account:
• The distance between the biogas engines of the same plant can be several meters. The harsh environment and the presence of potentially disturbing electromagnetic signals re-quire that the transmission line of unconditioned, raw sensor signals should be as short as possible.
• Therefore, every biogas engine has a local data acquisition module (from now on, called sta-tion), which performs the conditioning and digitalizing of the raw analogue signals acquired from the sensors.
The digitalized signals of every sub-station, then are forwarded to the main station that performs the following main tasks:
• Pre-processing of the data including
o Scaling
o Averaging, filtering
o Basic comparisons, and limit-monitoring
The interconnection between the stations are highly reliable industrial digital communication protocol – EtherCAT. EtherCAT (Ethernet for Control Automation Technology) is an open, real-time Ethernet-based real-time system. Its attractive characteristics make it suitable for automation applications.
• Data transfer: Ethernet/EtherCAT cable (min. CAT 5), shielded
• Distance between stations: 100 m (100BASE-TX)
• Data transfer rates: 100 Mbaud
• Delay: approx. 1 µs
In order to avoid on-site data representation and any other graphical user interface, an architecture version was implemented finally the concept of which is a headless architecture, with no dedicated local display. The main station therefore on one hand acts as a sub-station as it is able to acquire signals from the analogue sensors, on the other hand it serves as an endpoint of the EtherCAT network and a gateway to the remote server via Ethernet.
Control system components
The used PLC components are designed for industrial environments and conform the following regula-tions:
• Vibration/shock resistance: EN 60068-2-6/EN 60068-2-27
• EMC immunity/emission: conforms to EN 61000-6-2/EN 61000-6-4
• Protection class: IP 20
• Operating/storage temperature: -25...+60 °C/-40...+85 °C
• Relative humidity: 95 %, no condensation
Embedded PC
The local controller is an embedded PC. Thanks to their low power consumption (max. 3W) these devic-es are fanless. They are mounted to a DIN-rail, and have a compact size of 65 mm x 100 mm x 80 mm.
The core of the PC is a 32-bit ARM based CPU running with a 400 MHz clock. The operational memory is 64 MB RAM, and for local data storage a 256MB micro SD card is included by default. This can be ex-tended up to 4 GB.
The operating system is Microsoft Windows CE 6, and the control system is programmed to create a virtual Programmable Logic Controller.
In the absence of a monitor port, the operating system and its “virtual” display can only be accessed via the network, but covers most of the use cases.
In the event of a failure of the supply voltage, an integrated capacitive 1-second UPS provides sufficient energy for saving persistent data. It supports protocols such as real-time Ethernet, ADS UDP/TCP, Mod-bus TCP client/server or open TCP/IP-UDP/IP communication. The interfaces are: 1 x Ethernet 10/100 Mbit/s, 1 x USB device (behind the front flap), bus interface: 2 x RJ 45 (switched).
The analog input terminal processes single-ended signals in the range between 4 and 20 mA. The cur-rent is digitised to a resolution of 12 bits and is transmitted (electrically isolated) to the higher-level automation device. The EtherCAT Terminal combines eight channels in one housing. The measuring error is less than ±3% (relative to full scale value).
The input filter limit frequency is 1 kHz, and the default analogue-digital conversion time is 1.25 ms, which is more than needed in an application with so long time constants such as oil-condition monitor-ing.
The signal state of the EtherCAT Terminal is indicated by light emitting diodes. The error LEDs indicate an overload condition and a broken wire. The module also features built-in limit value monitoring.
The EtherCAT extension is connected to the end of the EtherCAT Terminal block. The terminal offers the option of connecting an Ethernet cable with RJ 45 connector, thereby extending the EtherCAT strand electrically isolated by up to 100 m. In the EtherCAT extension terminal, the E-bus signals are converted on the fly to Ethernet signal representation. Power supply to the EtherCAT extension electronics is via the E-bus.
The EtherCAT coupler acts as gateway between the EtherCAT fieldbus system and the connected Ether-CAT analog input terminal. The coupler converts the passing telegrams from EtherCAT to E-bus signal representation. The coupler is connected to the network via the upper Ethernet interface. The lower RJ 45 socket is used to connect further EtherCAT devices in the same strand.
The EtherCAT coupler needs external power supply since this module provides power to the other ones via the E-bus.
The Main station holds a PLC setup with the next modules:
• Embedded PC
• 8-channel analog (4-20 mA) terminal
• EtherCAT extension
Every station is equipped with its own power supply converting the mains 230 Vac to 24 V (1.5 A). The power supply circuit is protected with circuit breakers and fuses.
For easy installation, the input wires are bundled on a terminal block.
The housing is an IP 67 protected metal enclosure, the incoming and outgoing wires are placed in glands.
The sub-station includes a PLC setup with the next modules:
• EtherCAT coupler
• 8-channel analog (4-20 mA) terminal
• End terminal
Every station is equipped with its own power supply converting the mains 230 Vac to 24 V (1.5 A). The power supply circuit is protected with circuit breakers and fuses.
For easy installation, the input wires are bundled on a terminal block.
The housing is an IP 67 protected plastic enclosure with transparent cover, the incoming and outgoing wires are placed in glands.
The firmware of the DAQ hardware developed by ATEKNEA is responsible for receiving the data gener-ated by the applied sensors. The final version of the sub-stations are capable of detecting eight 4-20 mA channels in parallel with continuous or pulsed mode operation. The protocol of the pulsed mode signal was developed in cooperation with AC²T.
In December 2014, the preliminary field tests were started at the premises of BKG and RYTEC. During the first tests, the first version of the data acquisition software showed limitations. Therefore, Data Acquisition program running on the PLC was developed continuously based on the experiences gained through the pilots in Güssing and Frankfurt from the end of year 2014.
The initial version was ready to process 8 analog channels simultaneously, out of which one (dedicated channel-8) can operate in the pulse mode. At first run (after reset or power-up), the program waited for 30 seconds. If within this time frame the value of channel-8 rose to 20 mA, the program switched to pulse mode, expecting sequential output on channel-8. The PC based visualization program was told to be reported in this deliverable, however since then, other further development guidelines have been considered, namely it was foreseen that the sensors will be operated in pulse mode (including the cor-rosion and multi-sensors as well) in the future in order to minimize the required analog ports. There-fore, the following features have been implemented to enhance modularity and scalability:
• All 8 analog channels will be ready for pulse mode acquisition
• Local HMI visualization for setting up the PLC module
• Prepare the trending code for the visualization of 8x6 parameters
Major improvement was the implementation of a scalable and flexible code enabling easy scale-up of the data acquisition system by adding or replacing sub-stations or sensors.
Data structure
The total number of the measured data per plant is determined by 3 parameters: the number of stations (Güssing: 1, Frankfurt: up to 5), the number of analog channels available (8 per stations considering the currently used PLC modules), and the pulse count in pulsed mode (assumed to be less than 10). The in-put channels and the measured data are therefore stored in dynamically sized multi-dimensional arrays determined by these constants, which can be easily re-configured before installation.
Program
The main program consists of 3 parts:
• Data acquisition (or data generation for simulation in debug mode):
Calls ReadChannel function block for each input channels, converts the ADC values to 4-20 mA current value.
In debug mode, random values are generated.
• Main state machine
Handles sampling timer and prepares messages to be sent or entires to be logged based on the polled measured data of one station
• Communication
Sends the latest measured values or saves them to disk.
WP4 – DAQ software and GUI
Methodology
The purpose of this component is to manage the measured data received from the PLC and to provide configuration and visualization possibilities for end users. The component can be broken down into three main components:
• Condimon database in which measurement and configuration data is stored
• CondimonDaemon that collects and saves measurement data into the database
• CondimonGUI that provides visualization, parameter configuration user interface and handles measurements
In the current configuration all of these components run on the same host.
The relations between the three main software components are depicted below. All of the components run in a separate process. Both CondimonGUI and CondimonDaemon have access to the database: CondimonDaemon continuously saves the measured values, sent by the PLC, into the database; Con-dimonGUI can display the measured data in different views.
Applied technologies and hosting environment
The application uses the MySQL database engine as it is free, available on multiple platforms and suitable for the data quantity the Condimon system produces.
CondimonDaemon and CondimonGUI are implemented in Java (Java 1.6) because the Java platform supports both server and client applications well, furthermore it is platform independent so the Condimon system can be easily migrated to other platforms, for instance Microsoft Windows, on demand. For database connectivity the Java Database Connectivity (JDBC) library, provided by MySQL, is used.
The application was developed in the Eclipse Integrated Development Environment and consists of the following four Eclipse projects:
• CondimonCommon: Common functionalities for CondimonDaemon and CondimonGUI
• CondimonDaemon: The implementation of the CondimonDaemon backround process
• CondimonGUI: The implementation of the CondimonGUI application
• DatabaseTools: Classes for database connectivity and database operations
The platform of this component is hosted on a low energy consumption Shuttle PC running Lubuntu 14.10 operating system, which is designed for these kind of hardware types. The necessary environment has been set up via custom bash scripts for different purposes, such as installation, process monitoring and automatic start-up.
Condimon application components can be installed by executing the installation script created for Condimon. This script creates the necessary folders, copies the necessary files, sets the correct file permissions and registers CondimonDaemon as a standard Linux service thus ensuring that the CondimonDaemon data logger module is automatically started when the operating system starts.
The database structure and classes are detailed in D4.2 here we present the main features of the user interface.
1) Monitor view
This view is the default when the application starts.
In this view the desired parameters can be monitored for a given station and channel for the active measurement. The desired station and channel can be selected via the comboboxes in the upper right corner of the CondimonGUI window. The user can select which parameters to monitor by enabling/disabling the checkboxes next to the configured parameter names. The monitored parameters are displayed in different colors on the chart.
It is possible to select the timeframe of the measurement. By pressing the OK button, the new timeframe is applied.
When the monitored parameter value is above or below the configured threshold, the background of the corresponding parameter name turns red.
This view is the default when the application starts.
In this view the desired parameters can be monitored for a given station and channel for the active measurement. The desired station and channel can be selected via the comboboxes in the upper right corner of the CondimonGUI window. The user can select which parameters to monitor by enabling/disabling the checkboxes next to the configured parameter names. The monitored parameters are displayed in different colors on the chart.
It is possible to select the timeframe of the measurement. By pressing the OK button, the new timeframe is applied.
When the monitored parameter value is above or below the configured threshold, the background of the corresponding parameter name turns red.
2) History view
In this view the user can examine every measurement in the database. Selecting station-channel pair and parameters works the same way as in the Monitor view.
Under the parameter names the desired measurement can be selected by its start date. By default, the currently active measurement is loaded. When a measurement is selected, the whole timeframe of the measurement is displayed for the selected parameters. It is possible to select a smaller timeframe by setting the Start date and the End date fields.
By double clicking on a value on the chart, the value is displayed in the bottom left corner of the window.
3) Export database
In this view the measured data along with all the configurations can be exported in a mysql specific format. It is possible to select a date range in which the measured data will be exported.
If the user presses Cancel, the view is changed back to the Monitor view.
If the user presses Export, a dialog appears where the filename for the database file can be set. It is recommended to use the .sql extension for the database file. This file can only be imported by system administrators using MySQL-specific tools.
4) Import from CSV
It is possible to import CSV files to the database, but only files generated by the Condimon system are supported. If the user selects Import from CSV menu item from the Tools menu, a dialog pops up in which it is possible to select a CSV file. After selecting a file and pressing Open, the import process is started. Upon it is finished, the user is notified about the result.
Remote accessibility
On the test sites a Shuttle computer was installed and configured with LUbuntu 14.10 operating system with all the necessary software modules as well.
Both the data logging back-end application and the Condimon GUI were set up on the Shuttle. Condimon GUI is responsible for data visualization where the logged measurement data can be shown on different charts.
An isolated local computer network was created on the test field for Condimon devices (PLC and Shuttle) since their communication interface is based on TCP/IP protocol. This local network is controlled by a router device. On the test field an IP router was used with DD-WRT firmware and connected to the internet via wired connection.
The Condimon GUI application can be launched directly on the Shuttle’s local display however it is also possible to use a remote desktop connection (VNC) from another computer which is attached to the local network. When a VNC server is operating it is possible to use this computer’s local desktop environment from a remote device via a VNC client.
WP5 – Knowledge base and evaluation algorithm
The main objective of WP5 was to collect and analyse oil samples in laboratory to compare the results with the sensor system measurements. This way, valuable input was provided for the software development and to set up the knowledge base for correct signal interpretation.
Oil data evaluation and gas engine product range
Oil analyses from in-service gas engine oils were evaluated to get knowledge about the oil degradation process. A market research of available gas engine oils provided the range of products. Selected gas engines oils were evaluated in different artificial alteration methods including online sensor systems. Thereby, generated sensor results were compared to the laboratory analytical data to setup the knowledge base for proper signal interpretation. Results from field test were included.
The oil data interpreted showed that mostly TBN and or TAN limits were reached. In nearly two out of three samples at least the limit for TBN or TAN was reached.
Accordingly, TBN or TAN were selected as the critical parameters, and a comparison between these parameters was done. Principally, several operating paths could be possible to reach one of the limits. By decrease of TBN due to consumption of base reserve and without significant increase of the TAN, the limit of the TBN is reached first. Other way round, by generating acids during operating which could not be sufficiently neutralized by base reserve (TBN), TAN will be significantly increased with only minor consumption of TBN. In this case, the limit for the TAN will reached first.
Generally, a wide range of different operation paths at the TBN consumption is noticeable. Exemplarily for one selected gas engine oil, the limit was already reached after around 350 operating hours. For another oil change interval, the TBN limit was not reached even after 700 h. This behaviour can be due to different operating conditions during the operation of the engine. Thereby, changes of the gas compositions are supposed as the most relevant reason for these differences.
Summarizing, it can be said that due to different operating conditions – most probably due to changes in the gas composition – provoke different alteration behaviour of the lubricant. Therefore, a good oil condition monitoring is necessary for optimizing the use of oil. Application of the CONDIMON multi-sensor system is hence fully justified as the means for online lubricant monitoring.
Sensor evaluation by artificial oil alteration
Artificial alteration means applying elevated stress conditions to the oil sample to accelerate oil degradation in a short-term scale. Nevertheless, an artificial alteration procedure should remain as close to reality as possible. This way, the quality of lubricants under special operating conditions and the usefulness of sensor systems for special applications can be investigated without the need to perform time-consuming and expensive field tests.
Currently used standardized methods for the artificial alteration of engine oils evaluate different parameters of the oil performance. Most standards examine the thermal-oxidative stability of oils by exposing the lubricant to elevated temperatures and oxygen from air e.g. ASTM D4871 (Standard Guide for Universal Oxidation/Thermal Stability Test Apparatus) or DIN 51352 (determination of ageing characteristics of lubricating oils).
Based on the existing methods, an adapted alteration method was used to specially simulate oil life cycles in gas engines. Therefore, the lubricant was deteriorated at elevated temperature in a defined vessel able to blow gas into the oil. Additionally, a fixation was used to implement the proposed Condimon sensor system in the artificial alteration device.
In order to simulate the impact of different fuel qualities on lubricant degradation, two different alteration methods were chosen. In the first method, only air was blown through the lubricant. This method denoted with “air” should simulate mild conditions in an engine, e.g. the operation with natural gas almost free from contaminants that could form aggressive compounds. The conditions for the second method called “biogas” were based on the “air” method and adjusted to simulate the impact of biogas on accelerated oil degradation.
Also different sensor system were integrated to the sensor bypass: corrosion sensor, Condimon Multi Sensor (CMS) and a commercial oil condition sensor possible to measure conductivity, rel. permittivity, rel. humidity and temperature. As sacrificial layer for the corrosion sensor, lead was chosen for all these experiments.
In order to follow the oil degradation during the artificial alteration, oil samples were taken on a regular base. The oil condition was analysed in the laboratory expressed by the total base number TBN according to DIN ISO 3771, neutralization number NN according to DIN 51558 as well as oxidation according to DIN 51453.
The behaviour of the oils during artificial alteration are discussed by means of laboratory analyses. It was clearly demonstrated that TBN degrades much faster with the method “biogas” than with the method “air” for every oil. Similar tendencies can be seen by looking at the trends of the neutralization umber NN. Thereby, also a higher increase at the method “biogas” in comparison to the method “air” can be seen.
The trends of the conductivity were recorded during the artificial alterations. Thereby, mainly the typical bathtub curve could be observed: the conductivity of a liquid such as oil is given by the concentration of movable charge carriers. The conductivity of the fresh fluid is mainly given by the formulation of the additives and decreases in the beginning. After this, a period with more or less stable conductivity can be seen. If the built up of alteration products becomes dominant, the conductivity began to raise. This point is an indicator that the oil reaches the end of the lifetime.
When investigating permittivity values it can be seen that the starting point for the permittivity is not so much varying in comparison to the conductivity. The starting point for the evaluated fresh oils is between 2.1 and 2.3 which is a typical range for mineral oils. A closer look at the permittivity curves revealed that the permittivity trends showed a linear increase when recorded with the Condimon Multi Sensor and curves showing a bathtub trend were observed with the commercial oil condition sensor. The findings suggest that the measurements of the permittivity with the commercial oil condition sensor were influenced by the changes in the conductivity.
As the developed Condimon Multi Sensor shows the typical linear increase over the alteration time it can be concluded that this sensor has no significant influence of the conductivity for the desired gas engine oil which makes the sensor very suitable to monitor these fluids.
As to the corrosion sensor, the corrosion process starts at a certain alteration time (equivalent with a certain oil condition) showing a sharp response characteristic. At some artificial alterations, no corrosive attack of the sacrificial layer could be observed. This could be attributed to the fact that the oil was not corrosive against lead till the end of the experiment.
Special events like the simulation of a downtime period by stopping the alteration of the addition of a fresh oil were performed. It was found out that during the period where the alteration was stopped (= downtime period) no significant change of the sensor signals could be observed. As the alteration starts again, the signals (conductivity and permittivity) proceed the trend as before the simulated downtime period. As the oil was not corrosive against lead before the alteration was stopped also no significant change occurred during the downtime period – as expected. But shortly after the alteration was started again, the oil became corrosive to the lead lowering the signal for the remaining area.
Another special event referred to the addition of fresh oil. After a noticeable signal change of the corrosion sensor was observed, a certain amount of fresh oil (~ 25 %) was added to the artificial alteration. This addition of fresh oil stopped the corrosion process of the sacrificial layer immediately. By further alteration and hence oil degradation, the corrosion process started again as the critical point of acidification was reached again. This experiment confirms the behaviour of the corrosions sensor to be sensitive to a critical amount of acidification in the lubricant.
Sensor signal interpretation – algorithm
The comparison between the sensor signals and the laboratory analyses revealed that no general correlations were given. In-depth analysis revealed that the relationships were strongly depending on the oil formulation and the alteration behaviour in the desired application.
The evaluation of the trends of the conductivity showed that the oil limits were reached for oils providing the typical bathtub curve shortly after the increasing phase was started. Therefore, it is very important to analyse the complete trend of the conductivity to find the individual stages and consequently the condition of the oil.
The rel. permittivity showed a good correlation to the neutralization number of the oil. Thereby, correlations for the method “air” and “biogas” could be found widely independent from the oil type. As typical threshold, an increase of about 2 to 3 % increases of the rel. permittivity could be identified.
The signal of the corrosion sensor showed that at a certain amount of acidification the corrosion process started. This initial point for corrosion was also dependent on the oil formulation. Mostly, the initial point for onset of corrosion was at an increase of the NN in the range from 1 to 2 mg KOG/g giving a clear warning signal for the operator.
WP6 – Field tests
The field tests were performed at two locations: at project partner BKG in Güssing (Austria) and at pro-ject partner RYTEC in Frankfurt am Main (Germany). The evaluation of the CONDIMON sensor system was carried out in three stages: 1) laboratory work at AC²T and at ATEKNEA was carried out continuous-ly along with the development process. 2) at AC²T, an artificial alteration equipment was set up and used for the CONDIMON sensor system benchmarked against commercial sensors. 3) at ATEKNEA, the data acquisition modules and interfaces were tested by means of a signal emulator customized for the CONDIMON DAQ system.
After all the components were successfully evaluated and validated, preliminary field tests using the first prototypes of the CONDIMON sensor system were started in December 2014. The tests revealed input to further optimisation based on collection of useful real environment data from both plants. Based on this experience, AC²T and ATEKNEA further developed the system (see details in previous work packages) and the installed modules were substituted by the updated versions progressively. In July 2015, the final prototype of the CONDIMON multi-parameter sensor (CMS) was integrated and installed in both the biogas plants and AC²T laboratory for evaluation.
Currently, two Condimon sensor systems are operated at Rytec and one at BKG.
Preliminary field tests
The first sensors were installed by AC²T in December 2014. Thereby, a prototype of the developed cor-rosion sensor with lead as sacrificial layer was mounted into the engine. This sensor delivers signals of the remaining area of the sensing element as well as the temperature. Furthermore, a commercial oil condition sensor was also implemented into the engine.
The sensor signals (4-20 mA) were connected to the Programmable Logic Controller (PLC) as described in WP3. The PLC was connected to a shuttle PC as described in WP4.
Based on the first experiences, the following modifications were made:
• Software bugs have been corrected.
• System is able to receive signals from
o 8 analogue 4-20mA channels OR
o 7 analogue 4-20mA channels + one pulse mode channel (dedicated to channel-8).
The new firmware upgrade was installed at BKG by ATEKNEA in March 2015.
The capacitance values of the corrosion sensor showed the degradation of the sacrificial layer. During a downtime period of 7 days in April 2015, the signals of the corrosion sensors remain almost stable. This demonstrates that the corrosion process was interrupted or took place only on a very low level, respectively. After starting the engine again and reaching the temperature at the common operating conditions, the corrosion process proceeded as expected.
The same system was installed at RYTEC in April 2015. Under the operating conditions, the commercial oil condition sensor failed while the CONDIMON sensor system turned out to provide stable and reliable sensor data.
CONDIMON network settings
A small server computer was used for data logging and visualization at both sites. On the test sites, a Shuttle computer was installed and configured with all the necessary software modules as well (including MySQL database, Java JRE, etc.).
Both the data logging back-end application and the Condimon GUI were set up on the Shuttle. Condimon GUI is responsible for data visualization where the logged measurement data can be shown on different charts.
An isolated local computer network was created on the test field for Condimon devices (PLC and Shuttle) since their communication interface is based on TCP/IP protocol. This local network is controlled by a router device. On the test field, a router was used to connect to the internet via wired connection.
The Shuttle computer and the PLC were attached to the local network and a static IP address was assigned to them.
After the network connection between the PLC and the Shuttle had been established, the data logging service was started. Considering the fact that the PLC sends raw current (mA) values, these values should be recalculated based on the type of the given input. From the Condimon GUI application calculation coefficients can be configured for each stations and channels.
The final version of the sensors presented in the description of WP2 and the upgraded DAQ (WP3 and WP4) system were installed in July 2015. The measurements have been running since then and the measurement data is downloaded by the method descried later in this document.
The measurement signals show good accordance with the laboratory analysis. Here, a short summary of the signal analysis is presented.
CONDIMON Multi Sensor evaluation by field tests
Hereby, only the most important findings are highlighted:
Conductivity: The trend of the temperature compensated conductivity showed a steady increase in all observed periods. By looking at the oil analyses from the laboratory, an oil degradation can be noticed (decrease of TBN and increase of NN and oxidation).
Permittivity: by proper calibration of the permittivity sensor against temperature, the signal shows a steady increase of the rel. permittivity thus proving the effectiveness of the compensation of the electronic temperature effects.
Corrosion: the laboratory analyses confirm the immediate attack of the sacrificial layer as the limit for the NN was already reached.
The results from the field test and in-service gas engine oils largely confirmed the relationship between the sensor signals and the laboratory analyses. So, the most important objective of the CONDIMON project was achieved. Besides, the final CONDIMON multi-parameter sensor (CMS) became an attractive pre-marker prototype.
We can claim that both the final CMS sensor and the flexible data acquisition system is ahead of the current state-of-the-art, so the exploitation of the CONDIMON system has high market potential.
Potential Impact:
Potential impacts and socio-economic effects of the project:
Biogas production has significantly risen across the EU in the past years. According to the statistics of the European Biogas Association today there are more than 13 800 biogas plants in Europe with an installed gross capacity of 7400 Megawatt. By 2020 methane production will expectedly double compared to a decade ago and reach 24.2 billion m3. Growth tendencies are supported by the strong commitment of the EU policy makers to ease energy dependency and increase the share of renewable energy sources in the gross final energy consumption to 20% by 2020 in which biogas has a key importance.
However process optimisation through innovative technologies still has much potential to increase the productivity and profitability of existing and newly established biogas plants. Currently biogas engine operators often suffer from high costs associated with maintenance due to the special chemical attack on the engine and engine oil resulting from biogas process. Quality degradation in oil can attack essential engine parts leading to increased wear and corrosive wear which cause early failure of the machine. Despite much scientific research and patents proposing oil quality sensor approaches for certain parameters, currently there are no commercially available sensor systems measuring all key parameters of oil quality needed to reliably determine the necessity of oil maintenance.
The CONDIMON integrated sensor system for in-line oil condition monitoring covers the measurement of the most important oil condition parameters. The sensor system incorporates OEM sensors of permittivity, conductivity, viscosity, temperature and moisture content as well as a novel corrosion sensor. This unique sensor can directly measure the corrosion (acidification) of the lubricant, which is a critical parameter in combustion engines, especially in case of biofuel based operations. The Condimon sensor system is able to ensure the protection of the machine by online monitoring of the lubricant, while allowing the optimization of the oil change interval. The use of this technology leads to reduced maintenance costs and offers good potentials to increase profitability and competitiveness of the 13.800 currently operating biogas plants in Europe.
On the other hand, the socio-economic impacts of the project has to be mentioned: Environmental sustainability plays a critical role if we focus on socio-economic impact. The members of the consortium have investigated the possible impacts which could be experienced after the product takes its way on the market. The first possible and directly measurable impact could be achieved by the local retailer community. Obviously, training is crucial before the retailers could sell the product successfully. During the training activity, the knowledge of the retailers is growing about a technology, which lowers both the operation costs and the amount of the emission by the end users’ facilities. In parallel, the global aim of the EU is to constantly lower the emission , and the opportunity to fulfil these recommendations with a side effect of lowering costs will have an effect on sales motivation by the retailers. Therefore, the increase of income from sales is expected by the retailers, while lower operation costs and a possible decrease on the amount of emission by the end users could be achieved. These factors together will build up the CONDIMON system’s socio-economic impact results chain:
By the retailer: Retailer training spend -->Retailer trained-->Sales improvement-->Income increase
By the end user: New technology spend-->technology applied-->Decrease on operation costs and on environmental pollution-->Competitiveness increases
The main dissemination activities:
The consortium has prepared a detailed plan for dissemination which supported the effective promotion of the CONDIMON system. In execution of dissemination activities the Management Board oversaw and enforce that the rules set by Annex II. II.30. of the Grant Agreement and the Consortium Agreement are respected. In order to ensure confidentiality in exploiting and protecting the results new information on the Foreground were not published without the previous approval of the consortium members. The coordinator in cooperation with the Exploitation Manager ensured that the Management Board has all information necessary on time for decision making as indicated by the terms and condition. Based on the key aspects of dissemination established, the consortium has completed a number of promotion activities. For dissemination possibilities, a wide range of project relevant websites, presentations, seminars, information leaflets, newsletter have been examined through means of Internet, phone, personal contact press release etc. The consortium members, especially SME partners have decided to play an active role in project dissemination activities ensuring that no non-confidential information is published which would negatively affect the exploitation of the research results generated in the frame of the project. The results are described in light of the targeted audience. Images, screenshots and further materials emerged during project dissemination activities.
Exploitation of results:
While constructing viable financial models for the exploitation of Condimon, partners agreed that the largest volume of sales can be expected in Europe. This standpoint was partly based on the fact that the continent is the largest market inevitably leads biogas development, production and consumption and also on the in-depth knowledge, experience and current clientele that partners already have in this territory. This is also backed by discussions at the STLE 2015, although vital interest in commercialisation of the Condimon system outside Europe was expressed and important gas engine producers are located in the USA, e.g. Cummins, Waukesha. Thus, the regional biogas market was investigated in detail to explore the recent trends and explore the potentials for Condimon on the market.
In Europe, the largest boom in biogas installations were experienced between 2011 and 2012 with circa 1400 new operation sites. Over 70% of the new projects were based in Germany which is the strongest market in Europe with over 8700 biogas producing plants (in 2014). However, due to the revised feed-in tariffs in the past two years, the market in Germany has experienced a slowdown compared to the years of boost with around 340 installations in 2012 and expected 200 annual new projects so forth. The potential impact of the limits introduced on state support for feeding biogas produced electricity into the grid will expectedly push demands for further cost optimisation on both installed and newly established plants including economic maintenance solutions and technologies such as Condimon that help reducing operating expenses.
In terms of market position, the second strongest in Europe is Italy with 1,264 and Switzerland with 606 anaerobic digesters. According to the European Biogas Association, significant growth is expected in France, Denmark and in the UK partly due to the favourable policy decisions for biogas support in the next years. In France for example, the number of new installations is expected to reach 500 under the new energy bill introduced this year. While in Denmark the increase of feed-in tariffs and the endorsement of the 50% manure treatment target are inducing market growth. In the UK, biogas potential is greatly supported by the new Renewable Heat Incentive (RHI) that took off in May 2014 enabling higher feed-in tariffs for biogas from anaerobic digesters of all scale. On the general level, the European biogas production can expect a boost from the new end-of-waste criteria (EoW) recommendations that will expectedly lead to the legislative support for the utilisation of digestate the by-product of biogas production. The following tables depict in details the structure and production capacity of the European biogas industry.
List of Websites:
www.condimon.eu