A separate-type autothermal CH4 dry reforming system with exergy recuperation

Abstract

Currently, CO2 conversion and utilization have become a key to mitigate the global warming. In this study, a novel separate-type autothermal dry reforming of methane (S-ATDRM) system is proposed and simulated, in which the methane dry reforming combined with methane partial oxidation is performed in a circulating fluidized bed with exergy recuperation to eliminate the negative effect of the products of CH4 partial oxidation on the DRM reaction and further improve the CO2 conversion efficiency. The results demonstrate that this S-ATDRM system can achieve an exergy efficiency of 84.7 %, and about 1055.7 kW of exergy can be recuperated from the process for crude syngas cooling and reapplied for pre-heating of feedstocks of CO2, O2 and CH4. It is found that the largest exergy destruction in this system occurs in the partial oxidation reactor, which occupies ca. 45.6 % of the whole exergy loss. Comparing with the conventional ATDRM system, although the exergy of S-ATDRM system is decreased by approximately 0.3 %, the CO2 conversion is substantially increased by about 11.3 %.

Keywords

• Carbon dioxide
• Autothermal dry reforming
• Circulating fluidized bed
• Exergy efficiency
• Exergy recuperation