Enhanced high-purity syngas production and sustainable chemicals synthesis via chemical looping dry reforming of methane

Abstract

Dry reforming of methane (DRM) utilizes two major greenhouse gases, CO₂ and CH₄, to produce syngas (CO and H₂), which is an important chemical intermediate resource for high-value chemicals synthesis. However, conventional DRM faces challenges such as catalyst deactivation, low product selectivity, and an unsuitable syngas ratio for downstream chemicals synthesis. To address these limitations, we propose a chemical looping dry reforming of methane (CLDRM) method, which achieves high methane conversion, superior syngas selectivity, and high-purity syngas for chemicals synthesis. In this study, 100 cycles of experiments were carried out using the LaFe_0.8Al_0.2O₃ oxygen carrier. The results showed 88.3 % CH₄ conversion, over 99 % CO selectivity, and a syngas yield of 8.1 mmol/g with an H₂/CO ratio of 2 during the methane partial oxidation (POx) step. In the CO₂ splitting step, the system achieved 81.3 % CO₂ conversion with a CO yield of 2.6 mmol/g. The energy upgrade factor during the cycle reached 1.98. Furthermore, the performance of the proposed CLDRM-based chemicals production system was analyzed, taking acetic acid synthesis as a typical case. The new system achieved energy and exergy efficiencies of 62.9 % and 65.4 %, respectively, representing improvements of 11.5 % and 12.2 % compared to the conventional DRM system. Additionally, the new system reduced methane consumption by 8.84 % while increasing the CO₂ fixation rate by 50.54 %. In summary, the proposed CLDRM process offers a promising pathway for CO₂ reduction and cleaner utilization of CH₄ for high-value chemicals production, supporting the transition to a more sustainable and low-carbon future.