Experimental investigation of oxy-coal combustion at a 250 kW Combustion Test Facility

ABSTRACT Carbon Capture and Storage (CCS) technology has considerable potential to reduce CO2 emissions of the energy sector to near zero. Therefore it promises to make a major contribution in mitigating climate change, whilst enabling the continued use of fossil fuels over the coming decades. In addition, it will enhance the energy security of nations with significant fossil fuel reserves, and enable those relying on energy imports to maintain a more diverse range of supply (DECC, 2012). Oxy-fuel combustion is one of the most developed CCS technologies and is suitable for near-term deployment (Wall, 2011). However, in order to ensure the success of the first large scale plants, and thereby demonstrate the technical and economic feasibility of the technology, the fundamentals of the oxy-fuel combustion process have to be fully understood.

In oxy firing atmospheric N2 is substituted with CO2 from the recycled flue gas, in order to increase the exit CO2 concentration and to moderate the flame temperatures within the process. This changes the fundamentals of the combustion process and, as a result, oxy-coal combustion differs from conventional air fired combustion in a number of ways, including coal reactivity, flame characteristics, heat transfer and emissions performance. This paper, which explores the combustion of coal under oxy-fuel conditions in a state of the art 250 kW Combustion Test Facility (CTF), focuses on flame characterisation and heat transfer performance.