Cu/Zn/Zr/Ga Catalyst for Utilisation of Carbon Dioxide to Methanol-Kinetic Equations

This paper presents the kinetics of methanol synthesis from carbon dioxide and hydrogen over a Cu/Zn/Zr/Ga catalyst. Kinetic studies were carried out in a continuous-flow fixed-bed reactor in a temperature range from 433 to 513 K, pressures from 3 to 8 MPa, and GHSV from 1660 to 10,000 1/h for initial molar fractions of hydrogen from about 0.48 to 0.70, carbon dioxide from 0.05 to about 0.22, and carbon monoxide from 0 to about 0.07. Significant effects of temperature and the composition of the reaction mixture on the conversion degrees alpha(1) and alpha(2) were found. The Cu/Zn/Zr/Ga catalyst showed good stability over 960 h. XRD and CO2TPD characterisation were performed. Thefinally obtained results of kinetic tests were developed in the form of Langmuir-Hinshelwood kinetic equations. The numerical Levenberg-Marquardt method was used to estimate the kinetic equations. The average relative error of fitting the kinetic equations to the experimental data was 18%.