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Industrial Thermal Energy Recovery Conversion and Management

Periodic Reporting for period 3 - I-ThERM (Industrial Thermal Energy Recovery Conversion and Management)

Berichtszeitraum: 2017-10-01 bis 2019-03-31

In the European Union, industrial processes are currently responsible for one third of primary energy consumption. Most of these processes, however, involve a rejection of large quantities of heat to the environment whose recovery as heat or conversion to another form of energy, such as electricity, can reduce energy demand, lead to fuel cost savings and contribute to meeting emission reduction and decarbonisation targets.

In recent years, the potential for heat recovery has been increasingly recognised and the heat recovery business is expected to expand significantly. However, for this to materialise and for the European manufacturing and user industries to benefit from these developments, technological improvements and innovations should take place aimed at improving the energy efficiency of heat recovery equipment and reducing installed costs.

In this context, the aims of the I-ThERM project are to investigate, design, build and demonstrate innovative plug and play waste heat recovery solutions and the optimum utilisation of energy within and outside the plant perimeter for selected applications with high replicability and energy recovery potential in a wide temperature range (70°C to 1000°C).
In the first three years of I-ThERM, the coordination and management of the project ensured that all activities fulfilled the requirements of scope, timeliness and quality. Synergy between the partners was achieved by regular communication and information exchange while dissemination activities were carried out through international conferences and workshops, attending international events including the SPIRE ones in Brussels, scientific publications and general paper based material, as well as regular posts on social media and on the project website.

The heat recovery potential in the European Union was assessed through a literature review which identified and quantified primary energy consumption in the major industrial sectors, considered waste heat streams and their temperature levels, and potential energy recovery technologies. Moreover, barriers for the mass deployment of energy recovery technologies have been identified through a questionnaire that was distributed to around 50 experts from 11 European countries.

The EINSTEIN energy auditing tool-kit has been enhanced and now includes the I-ThERM technologies. Routines to automatically analyse historical monitoring data, calibrate the models, forecast energy consumption and optimise systems performance have been implemented. These capabilities have been coupled with the innovative I-ThERM supervisory monitoring and control platform and they will be tested and evaluated with data from the demonstration sites.

The I-ThERM project considers the design, manufacture and demonstration of direct exhaust heat recovery systems using innovative heat exchangers.

The Heat Pipe Condensing Economiser (HPCE) allows to cool the exhaust gases below their dew point to enhance the heat recovery. For this reason, innovative coatings for corrosion protection against environments characterised by the presence of sulphuric acid have been developed. A 200 kW HPCE system was conceived in terms of thermal and mechanical designs, heat pipe coating application during mass-scale manufacturing, instrumentation and controls.

The Flat Heat Pipe System (FHPS) aims at recovering heat from high temperature radiating surfaces. A prototype module of the FHPS has been designed, manufactured and tested first in the R&D laboratories and then in the wire rod mill facility of Arcelor Mittal Gijón (Spain). The experimental dataset allowed the calibration of the design tools and proposed an improved design of the modular FHPS with greater number of modules and a high emissivity coating.

The I-ThERM project also considers the conversion of waste heat to electricity using two new bottoming thermodynamic cycles: the Trilateral Flash Cycle (TFC) for low grade applications (70 to 200°C) and the a Brayton cycle operating with Carbon Dioxide in the supercritical state (sCO2) for medium to high temperatures ones.

A full-scale 100 kW TFC unit has been designed with the support of complex modelling activities which aimed at assessing the energy conversion performance also at off-design and transient operating conditions. The developed TFC system now has a high technology readiness level. It is characterised by a packaged design and power electronics provision for connection to the European electricity grid. The TFC system has been further tested at the Technology Centre of Spirax Sarco (UK) and soon will be demonstrated at the TATA Steel site at Port Talbot (UK).

The demonstration site for the sCO2 system is an industrial scale test rig at Brunel University London that has been purposely designed for the I-ThERM project. The experimental facility comprises a 800 kW gas fired heater, generating 750°C exhaust gas temperature, and a packaged system incorporating the Compressor-Generator-Turbine (CGT) unit and ancillary equipment for lubrication, drainage electric power conversion. The sCO2 system also uses an innovative exhaust heat recovery heat exchanger which has been installed in the exhaust duct of the heater and transfers heat directly to the CO2 working fluid of the sCO2 power system.
The ambition of the I-ThERM project is to develop and demonstrate heat recovery technologies that will overcome many of the disadvantages of conventional technologies and create a pathway for much wider adoption of heat recovery by industry. In the first three years of the project significant progress has been made beyond the state of the art, namely:
- The EINSTEIN tool-kit has been enhanced to include the I-ThERM technologies as well as on-line monitoring and optimization capabilities.
- A packaged, plug and play low grade heat to power conversion system based on the Trilateral Flash Cycle has been designed and built for pilot testing and design optimisation.
- A single ~50 kW shaft Compressor, Generator and Turbine (CGT) unit for high temperature heat to power conversion working with supercritical carbon dioxide has been designed and manufactured.
- An innovative microtube heat exchanger for direct heat recovery from high temperature exhaust gases to supercritical CO2 of the sCO2 power cycle has been designed and manufactured.
- A 50 kW sCO2 power cycle and associated equipment have been designed and manufactured ready for testing and evaluation.
- A heat pipe condensing economizer has been designed to harvest sensible and latent heat from corrosive exhausts.
- The design of the flat heat pipe system was optimized thanks to test campaigns on a prototype in laboratory and the actual demonstration site.
- Coatings for corrosion protection against environments characterised by presence of sulphuric acid have been developed and are currently being evaluated.
- Substantial know-how is being developed on heat recovery and waste heat to power conversion systems. The creation of this knowledge and dissemination to the scientific and industrial communities as well as policymakers, will lead to greater awareness of the potential of these technologies and facilitate their adoption by industry. Apart from employment opportunities, this will lead to a reduction in energy consumption and greenhouse gas emissions and will contribute to meeting the EU’s emission reduction targets.