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ADVANCED MAINTENANCE ADVISORY SURVEILLANCE SYSTEM FOR EQUIPMENT OPERATING IN HOSTILE ENVIRONMENTS

Objective


Amass Software System

The software system developed in the Amass project is a site orientated data collection facility. It relates the data to the site location ( diagrams and location keys) and date of measurement. The system includes also tools for processing data, developed in the project. Others tools can be added to the system by the user.
The AMASS system is a computer based system, PC compatible running Microsoft Windows 3.11/3.0 with DOS 6.2 containing a multilingual interface to allow the user to choose the working language.
Images, data and tools can be registered and stored. The data can be stored in chronological order(time stamped) with reference to the location(Image and location code) of the component. A diagrammatic boiler display can be used to identify the boiler sub-components and associate data. Data can be accessed using various keys such as: site, time, component location, sensor type, etc.
The data analysing tools developed from the AMASS sensors, Thin layer activation, Steam side oxide measurements and Feroplug were registered in the system. The output from these is metal loss data and temperature data. This output may be used in the tube life algorithm tool, also included in the system, which provides tube life information based on wall thinning rates and temperature of operation. The data input for this tool may alternatively come from conventional sources, such as thermocouples and ultrasonic wall thickness measurements.

Off-Line Techniques

The results obtained with the development and application of the off-line techniques were successful.
- The CAV Technique allowed the location of sites of high gas flow and erosion damage. Modifications were made in the boiler and important economic and environmental benefits were achieved.
- The LS Technique was applied in laboratory with good results. However, for boiler applications, improvement of the capability and sensitivity of the technique is required.
- The applicability and accuracy of the UT measurement method of boiler tube internal oxide was proved in laboratory and field trials. Additionally, a very important tool, an algorithm to calculate the temperature to which the tubes are submitted, was developed.

On-Line Techniques

The results obtained with the development and application of the on-line techniques were not so good as anticipated in the beginning of the project.
- The waterwall corrosion probe developed and tested in laboratory was tested in a boiler during the field trials. However, the results of the testing were not satisfactory. Further developments and testing are required to improve the probe robustness to endure boiler furnace environments.
A superheater corrosion probe was additionally included in the project and tested with satisfactory results.
- The erosion monitor based on the TLA technique can be used to establish erosion trends but has some limitations(short distance between source and detector, high cost of the equipment, well trained operator).
- The temperature monitor is not so accurate as original expected.. One steel type is not enough to cover the 600-700 ºC range. Two steel types are necessary. The accuracy of this monitors is +/- 15 ºC, lower than the target accuracy of +/- 5 ºC.
The failure of boiler, heat-exchanger and process heater tubing in erosion-corrosion environments is one of the major causes of availability and production losses in power, process and manufacturing industries. In conventional power plant boilers, erosion, corrosion and creep processes account for nearly 50% of all tube-failures. Such failures cause unplanned, costly forced outages resulting in availability and environmental penalties.

An on-line method of tracking the erosion-corrosion and relating this to life consumption, would be a major step forward in preventing unexpected tube failures and reducing maintenance costs over a range of industries, with an expected benefit to European industry of 500 MECU's per annum.

The project specifically addresses high temperature tubing in coal and oil-fired boilers. The major innovation is the development of an integrated computer based system for life prediction and monitoring based on off-line and on-line measurement and monitoring techniques. the on-line methods will include : the use of monitors based on thin layer activation to measure tube erosion, an electrical resistance probe to monitor metal loss due to corrosion and an implant technique based on changes in magnetic permeability of duplex stainless steel implant as a robust means of measuring tube temperatures. The location of tubing susceptible to creep and metal wastage by corrosion and erosion will be determined by UT internal oxide thickness measurements, as a means of identifying tubes suffering overheating; Laser Shearography to detect metal wastage and Cold Air Velocity measurements to detect areas of higthest erosion. These locations will be selected as the sites for installing the one-site monitors.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

ELECTRICIDADE DE PORTUGAL
Address
Av. Estados Unidos Da America 55
1700 Lisboa
Portugal

Participants (6)

Cormon Ltd
United Kingdom
Address
70 South Street
BN15 8AJ Worthing
EMPRESA NACIONAL DE ELECTRICIDAD SA
Spain
Address
Principe De Vergara 187
28002 Madrid
ERA Technology Ltd.
United Kingdom
Address
Cleeve Road
KT22 7SA Leatherhead - Surrey
INST DE SOLDADURA E QUALIDADE
Portugal
Address
Rua Tomas De Figueiredo 16A
1500 Lisboa
MAGUE IND METALOMECANICAS SA
Portugal
Address
Estrada Nacional 10
2616 Alverca
UNIV ZARAGOZA
Spain
Address
Maria De Luna 3
50015 Zaragoza