Description
One of the methods of eliminating CO2 impact on climate is combustion in oxygen instead of air. However this technology has serious disadvantages. The main objective of the project is to evaluate new combustion technology, combining combustion in oxygen and MILD combustion. New technology should result in increase of efficiency, reduction of harmful species formation and reduction in boiler size and in fuel-flexibility. In the first phase coal combustion model will be developed and validated. In the second the model will be applied for real-scale boilers modelling. New technology should result in mitigation of climate changes, thus whole man-kind will benefit from the project. SINTEF will play main role in developing models while SUT will concentrate on modelling of real scale boilers.The main role of the donor partner is to develop model of a single coal particle combustion and next to develop models of a pulverized coal flames under oxy-MILD mode. On each stage of the project intensive contact are necessary. Partnership will allow to combine knowledge on combustion mechanism which is in SINTEF with experience in modelling boilers which is at SUT.
Summary of project results
The aim of the project was to develop a coal combustion technique suitable for CO2 separation. The project was aimed at demonstrating advantages of a new combustion technology, which combines benefits of already known MILD and OXY combustion techniques. It was shown that thanks to this combination, energy consumption for external recirculation, typical for oxy combustion technique, can be reduced and that produced flue gases will be of significantly better purity. Moreover it was proven that better fuel flexibility of the boiler can be achieved when compared to standard combustion techniques. The primary idea verified in the project was that high pressure oxygen, injected to a specifically designed combustion chamber, can entrain large amounts of flue gases. As a result considerable dilution of oxygen can be achieved before its contact with the fuel and a MILD combustion regime can develop. These concepts were successfully verified using mathematical modelling. Furthermore, currently existing mathematical models of a single particle combustion were developed for standard combustion conditions and could not be applied to evaluate the MILD-OXY combustion technique. Therefore a new combustion model of a single particle combustion, dedicated for MILD oxy combustion, was developed and applied in the design and development of the MILD-OXY combustion boiler. The model was developed using results of simulations of burning particles in turbulent flow in prototype geometries by means of the so called Direct Numerical Simulation. Such an approach allowed for taking into account the particle turbulence interactions affecting the combustion process. Another important achievement of the project was a new test facility designed and built during the project implementation. The facility allows for measuring rates of reactions of char particles in oxidizing atmospheres and finally will lead to better understanding of the processes as well as improvement of modelling of large combustion systems. The technology proposed within this project was also assessed thermodynamically and ecologically. Operation of the MILD-OXY combustion boiler within an entire power plant has been critically assessed. It has been shown that overall efficiency of the whole plant can be significantly increased which finally proved that the new combustion method can have significant input on mitigation of CO2 emission to the atmosphere.
Summary of bilateral results
Successful implementation of the project was possible by intensive cooperation of the consortium partners and research groups realizing tasks within work packages. Results obtained in many of the realized work packages were used in other WPs, thus requiring extensive data sharing and transferring of knowledge between consortium partners and research groups. The cooperation and sharing of knowledge lead also to better understanding of analysed processes and new ideas in solving problems during project implementation. This in turn lead to new investigation paths. In particular two MSc thesis topics were defined and temperature measurement technique tested within the project were stimulated during discussions during consortium partner meeting. Other important aspects of the cooperation were two project proposals prepared by SINTEF and SUT, one of which received funding. As a result of exchange of knowledge a PhD thesis topic was defined and is realized in cooperation between project partners.