Process Simulation of Co-Gasification of Raw Municipal Solid Waste and Bituminous Coal in CO2/O2 Atmosphere

Abstract

An integrated CO2/O2 co-gasification system of municipal solid waste (MSW) and bituminous coal (BC) with CO2 capture was developed and simulated by the Aspen plus, which mainly consisted of three processes: air separation unit, co-gasification system, and CO2 absorption unit. In addition, raw syngas composition, cold gas efficiency (CGE), and overall energy efficiency (OEE) of the entail system were evaluated in detail with respect to the main operating parameters (gasification temperature, T; oxygen equivalence ratio, Ro; mole of CO2 to carbon ratio, Rc; and the MSW blending ratio, RM). The results indicated that the addition of BC improved the gasification of MSW. Higher gasification temperature increased CGE and OEE. Increasing the Rc ratio led to the decrease of H2 mole fraction due to the enhanced reverse water-gas shift reaction. In addition, the CGE and OEE of the system decreased with increasing RM. From the analyses of the parameters, the most optimal operating conditions were set as T = 900 °C, Ro = 0.2, Rc = 0.5, and RM = 0.6, and the corresponding OEE of the system reached 0.57. The system can achieve a large processing capacity of MSW at the cost of the efficiency loss of this condition.