Optimization of Carbon Dioxide Hydrogenation to Methanol over Copper-Based Catalyst

Abstract

This study examines the utilization of process optimization as a viable strategy for addressing the issue of global warming through the conversion of carbon dioxide into methanol. In the realm of computational chemistry, the response surface methodology approach has evolved as an alternative for optimizing the reaction parameters through the utilization of statistical models. In the present study, promoted copper/zinc oxide/alumina catalyst was used for carbon dioxide conversion to methanol. The primary objective of the study was to enhance the overall methanol yield by optimizing the various factors in the methanol synthesis. This was accomplished by employing a combination of response surface methodology and one factor at a time techniques. The creation of statistical models was used to optimize the essential factors, and subsequently, one factor at a time. This helps in determining the optimum pressure, temperature, and hydrogen/carbon dioxide molar ratio. Impregnation technique was employed for the synthesis of promoted copper/zinc oxide/alumina catalyst. The analysis of variance results suggested the reduced quadratic model for carbon dioxide conversion, methanol selectivity and methanol yield as responses. The optimum process operating conditions were found to be the hydrogen/carbon dioxide ratio of 10, temperature of 300°C, pressure of 31 bar and gas hourly space velocity of 2160 mL/g.h, in which 28.6% carbon dioxide conversion, 59.2% methanol selectivity and 16.4% methanol yield were achieved. The catalytic performance was then investigated for high pressure range of 40 – 80 bar with other conditions were fixed at optimal value. The carbon dioxide conversion and methanol selectivity were found to increase with increasing pressure. The highest catalytic performance was achieved at 80 bar with carbon dioxide conversion of 68.35%, methanol selectivity of 93%, and methanol yield of 63.57%.

Keywords

• response surface methodology
• carbon dioxide hydrogenation
• methanol synthesis
• process optimization
• copper-based catalyst
• impregnation