Effect of ZnAl2O4 Phase on Modified Cu-X-Zn/ZnAl2O4 (X=La, Sm, Ce) Catalysts for the Production of Methanol

Abstract

Effect of ZnAl2O4 Phase on Modified Cu-X-Zn/ZnAl2O4 (X=La, Sm, Ce) Catalysts for the Production of Methanol As interest in carbon neutrality grows worldwide, methanol synthesis reactions are attracting attention as a Carbon Capture Utilization and Storage(CCUS) technology [1]. Methanol is the most widely used chemicals for the production of petrochemical products such as formaldehyde, olefins and acetic acid. Moreover, it is used as an environmentally friendly fuel of automobiles such as dimethyl ether (DME) [2]. The Cr2O3/ZnO (BASF) and the Cu/ZnO/Al2O3 (ICI) catalysts used as a commercial catalyst [3]. In our previous work, a mixture of ZnO and Zn-Al-Oxides spinel with a Zn/Al ratio of 3 was developed for methanol sysnthesis. It was found that the La promoter can enhance the sintering resistivity of the copper catalysts as well as the promotion effect of Lanthanide metal was confirmed [4]. In this study, a mixture of ZnO and Zn-Al-Oxides spinel with various Zn/Al ratio (1, 2, 3) was developed. The CuXZn/ZnAl2O4 (X = La, Ce, Sm) catalyst was prepared by deposit co-precipitation method. A Cu/Zn/Al2O3 catalyst was prepared by co-precipitation method as well for comparing the experimental results. The produced catalysts were characterized by various methods including N2 physical adsorption, H2-TPR, N2O chemisorption, XRD, CO2-TPD, XRF and TEM. The methanol synthesis was performed with a mixed gas of H2/CO/CO2/N2 in a fixed bed reactor under the conditions of 250 oC, GHSV 4,000 h-1 and 30 and 40 bar. This result can be interpreted that the CuZn/ZnAl2O4 catalyst showed higher thermal stability and lower sintered than the Cu/Zn/Al2O3 catalyst. Adding La, Ce, or Sm to the Cu-X/ZA500 catalysts enhanced the CO2 conversion in comparison to Cu/ZnO/Al2O3 as a reference catalyst.