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 %.