Improving coal gasification with in situ CO₂ capture by pressurization in interconnected fluidized beds

The technical route of coal gasification with in situ CO₂ capture using CaO sorbents was proposed via interconnected fluidized beds (ICFB) system, however, the defect of mismatch between the optimal coal gasification temperature and the optimal sorbents carbonation temperature limited the application. This paper modified the mentioned defect by pressurization. The coal gasification process with CO₂ capture was simulated using Aspen Plus. It was analyzed that the effects of gasification temperature, pressure, sorbents/coal ratio on gasification products composition, CO₂ capture efficiency. The effect of different bed materials was also discussed. The results indicates the pressure range of 0.7-0.9 MPa with the gasification temperature range of 740-760°C is favorable considering the match of coal gasification and sorbents carbonation temperature. Moreover, the optimal sorbent/coal ratio is about 0.38 under the condition above. The use of CaO sorbents reduces the CO₂ concentration in the exit of the gasifier about 53.53%, as well as partly promotes coal gasification degree and H2 yield, compared to quartz sands.