Fuel reactor modelling in chemical looping with oxygen uncoupling process

Solid fuel combustion via chemical looping with oxygen uncoupling (CLOU) represents a novel route for CO2 capture with minimal energy penalty. An essential part of the viability of a CLOU system is based on the behaviour of the fuel reactor. This paper presents a one-dimensional fluidized bed model capable of describing the operation of the fuel reactor involved in CLOU. The model considers physical phenomena relevant to CLOU, such as oxygen carrier decomposition, combustion of coal with molecular oxygen, fluidized bed hydrodynamics, and transfer of heat within the reactor. The performance of a CLOU fuel reactor fed with bituminous coal and a TiO2-supported CuO oxygen carrier was evaluated by means of modelling. A reference case was first defined and simulated, after which the effect of various process parameters on the results was assessed by parameter variation. For the reference case conditions with a temperature of 960 degrees C and solids inventory of 400 kg/MWf in the reactor and without utilization of a carbon separation system, a CO2 capture efficiency of approximately 90% was predicted. A CO2 capture efficiency of 95% could be reached by optimizing the operating conditions. It was found that when using low-reactive coals, a carbon stripper is required to obtain a feasible CO2 capture rate. Overall, the model predictions appeared to be in agreement with results presented in the literature. (C) 2015 Elsevier Ltd. All rights reserved.