Coke-promoted Ni/CaO catal-sorbents in the production of cyclic CO and syngas

• Published in: Sustainable energy & fuels 2021-12, Vol.6 (1), p.81-88
• Main Authors: Jo, Seongbin, Lee, Jong Heon, Woo, Jin Hyeok, Kim, Tae-Young, Ryu, Ho-Jung, Hwang, Byungwook, Kim, Jae Chang, Lee, Soo Chool, Gilliard-AbdulAziz, Kandis Leslie
• Format: Article
• Language: English
• Subjects: Calcium carbonate; Calcium oxide; Carbon dioxide; Carbon sequestration; Carbon sources; Coke; Conversion; Decomposition reactions; Methane; Reforming; Sorbents; Synthesis gas; Thermal energy
• ISSN: 2398-4902; 2398-4902
• DOI: 10.1039/d1se01136g

Compared with conventional CO 2 capture and utilization (CCU), the integrated CCU (ICCU) process has attracted attention in reducing total thermal energy and ensuring a simplified process. CO 2 capture and the subsequent dry reforming of methane (DRM) during the ICCU employing Ni/CaO catal-sorbents has been proposed for the conversion of waste CO 2 with CH 4 into syngas. Here, coke-promoted Ni/CaO catal-sorbents were fabricated via CH 4 pretreatment, and a highly efficient ICCU process for producing CO and syngas was proposed. High CO 2 conversion and high CO production were achieved in the CO 2 conversion step employing the reverse Boudouard reaction in tandem with CO 2 capture. In the following CH 4 conversion step, the spent catal-sorbents were regenerated into syngas via a reaction with CH 4 , and the carbon sources for the reverse Boudouard reaction were supplied by CH 4 decomposition. The C-Ni/CaO catal-sorbent exhibited excellent performances of CO 2 capture capacity, and CO and H 2 productivities in consecutive CO 2 and CH 4 conversions. However, the coke-promoted Ni/CaO catal-sorbents were not completely regenerated in the CH 4 conversion step after the 5 th cycle, which might be due to the sintering of Ni 0 /NiO and CaO/CaCO 3 materials and the excess amount of coke deposited on the surface of C-Ni/CaO catal-sorbents. Highly efficient CO and syngas production in a cyclic system was proposed using coke-promoted Ni/CaO (C-Ni/CaO) catal-sorbent. The C-Ni/CaO exhibited high CO production in CO 2 conversion and syngas production in CH 4 conversion step, respectively.