Thermodynamic analysis of integrated sorption-enhanced staged-gasification of biomass and in-situ CO2 utilization by methane reforming process based on calcium looping

Abstract

Sorption-enhanced H2 production using CaO promotes H2 generation by capturing CO2 in the form of CaCO3. Coupling methane reforming of CaCO3 in sorption-enhanced H2 production combines CaO regeneration with in-situ CO2 utilization. This integrated concept is expected to achieve high H2 production with CO2 capture and in-situ conversion into syngas. To evaluate the overall performance of the integrated sorption-enhanced staged-gasification of biomass and in-situ CO2 utilization by methane reforming process, the thermodynamic simulation was performed using Aspen Plus. The parameter optimization of the integrated process was carried out. The performance of the integrated process was also compared with two other processes, such as the serial sorption-enhanced staged-gasification and methane reforming process and the standalone sorption-enhanced staged-gasification process. The results exhibit that integrated methane reforming enhances H2 production from sorption-enhanced staged-gasification, because it can lower the CaO regeneration temperature and enhance the CO2 capture capacity. The integrated process produces a total gas product with H2/CO around 2, which is suitable for direct Fischer-Tropsch synthesis. Compared with the serial sorption-enhanced staged-gasification and methane reforming process, the integrated process results in 73.5% less CO2 emission and 135% more CO2 utilization. Moreover, the integrated process exhibits the higher energy conversion and exergy efficiencies than two other processes, which are as high as 74.5% and 68.6%, respectively. This work shows that the integrated process has technical and environmental potential for the utilization of biomass and CH4 to produce H2 and syngas with CO2 capture and in-situ utilization.