Title: Extension and evaluation of a macroscopic model for syngas-fueled chemical looping combustion
Abstract: Syngas-fueled Chemical Looping Combustion (syngas-CLC) which can be integrated with ex-situ gasification of coal has advantages over the direct use of coal in CLC: (i) no requirement of carbon stripper, (ii) no interaction of oxygen carrier with coal ash, (iii) no loss of oxygen carrier with the draining stream of ash. Few works on simulation of syngas-CLC were performed, although experimental investigations were extensively carried out. In this work, a macroscopic fuel reactor model is extended to a lab-scale 500 Wth reactor. The model based on fluid dynamics, mass balance and reduction kinetics is solved with MATLAB® codes and validated against experiments. Influences of various operation parameters are evaluated to study the flexibility of this model. It is shown that the model can give satisfactory predictions for fuel reactor of a syngas-CLC system, independent on the operation conditions. Variations of syngas composition, temperature, solids circulation and oxygen carrier inventory show different effects on flue gas composition and combustion efficiency. After thorough simulation, a region for a combustion efficiency of ηC = 99.9% is proposed, with which the optimized conditions for the 500 Wth reactor are established. An oxygen carrier inventory as low as 50 kg/MWth can assure the complete syngas combustion.