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

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 LaFe0.8Al0.2O3 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.