DFG Collaborative Research Center/Transregio 129: Oxyflame

Copyright: © WSA Development of Models and Methods to describe Solid Fuel Combustion in an Oxy Fuel Atmosphere

The continuously increasing global energy demand and the ongoing global rise in the coverage of this demand from fossil fuels is in stark contrast to the need to reduce CO₂ emissions. At the same time, the provision of energy from biomass firing - both by blending in and by the complete replacement of conventional coal firing - is becoming more and more important. The scenarios of the IPCC report (IPCC = Intergovernmental Panel on Climate Change) clearly show the need for CCUS technologies (CCUS = Carbon Capture Usage and Storage). Thus, according to the current status, especially BECCUS solutions (BECCUS = Bio-Energy Carbon Capture Usage and Storage) will be required shortly, to achieve both: i) the necessary reduction of CO₂ emissions and ii) the ability to retroactively remove the expected overshoot in CO₂ emissions from the atmosphere.

The oxyfuel combustion process investigated in this project represents one of the most promising technologies for CO₂ capture. In the oxyfuel process, the fuel is burned in a mixture of oxygen and recirculated flue gas, instead of air. This produces a flue gas with a very high CO₂ content, which can be processed for further use in just a few subsequent steps. While the main focus of the research project in the last years was to investigate the effects of the changed reaction atmosphere (CO₂/O₂ vs. air) on the combustion of coal, this funding period will focus on the combustion of different biomasses. The test rigs, measurement techniques, and knowledge gained in previous funding periods concerning physicochemical modeling will be used and further enhanced for biomass combustion in an oxyfuel atmosphere.

These strongly interdisciplinary scientific questions are being worked on within the Collaborative Research Center (CRC) Oxyflame, together with scientists from RWTH Aachen University, Ruhr University Bochum, and TU Darmstadt. The overall goal is to develop a numerical tool that can be used to mathematically describe oxyfuel combustion in large-scale plants for a wide range of fuels. Detailed experiments of varying complexity enable the development of a fundamental understanding of the processes involved and their dependence on the respective governing parameters - from the micro-scale to the cross-scale interaction. Elaborated combustion investigations on different scales provide e.g. important data for the validation of numerical simulations so that finally reliable calculation methods can be made available, which greatly simplify the development and design of burners and combustion chambers for oxyfuel power plants with solid fuel combustion. The reduction in the experimental effort required for a new design thus results in a significant reduction in the time required for power plant engineering.