Efficient Way of Carbon Dioxide Utilization in a Gas-to-Methanol Process: From Fundamental Research to Industrial Demonstration

Efficient utilization of CO2 to produce clean liquid fuels and various petrochemicals has attracted significant attention during the past decades. This review mainly focuses on our efforts and main achievements during the development of a CO2-utilizing Gas-to-Methanol (CGTM) process, which is composed of CO2/steam-mixed reforming and methanol synthesis via CO2 and CO hydrogenation. Experimental apparatus at different scales, ranging from lab to demonstration, have been established to pursue an efficient CGTM process with enhanced energy efficiency and reduced CO2 emissions. The proposed CGTM process employs a proprietary coke-resistant Ni-based catalyst in the reforming section, which is very stable under a 1000-h accelerated stability test. Based on the results of the process simulation and optimization obtained by using Aspen Plus, a CGTM demonstration plant with a methanol-production capacity of 10 t/day is designed and constructed, which comprises a reforming section (co-feeding CO2 into the reformer), a methanol synthesis section, and a recycling section. During the continuous operation for 1000 h, the CGTM demonstration plant exhibited a satisfactory performance, which is in good agreement with the design values. The overall thermal efficiency is shown to be superior to that of the conventional Gas-to-Methanol (GTM) processes, and the CGTM process is economically feasible given that the NG price, methanol price, and the plant scale are located in the following range of 1–5 $/MMBTU, 350–500 $/Mt, and 2500–5000 TPD, respectively. Furthermore, the proposed CGTM process would be even more competitive in the case of a higher carbon tax.