Journal of Industrial and Engineering Chemistry | 2021
Effect of surface acidity-basicity balance in modified ZnxZryOz catalyst on its performance in the conversion of hydrous ethanol to hydrocarbons
Abstract
Abstract ZnxZryOz and modified MuZnxZryOz (M\xa0=\xa0Si, W, Sc, Mg)/ Zn/(W-Zr) catalysts were studied in conversion of hydrous (4\xa0wt% H2O) ethanol at P =15\xa0bar, T\xa0=\xa0450\xa0°C and WHSV\xa0=\xa00.8-7.9 h-1. The basicity of the catalysts changed from 0.015 to 0.66\xa0mmol/g and the acidity from 0.07 to 0.24\xa0mmol/g resulting in a wide range of basicity/acidity ratio (R) of 1.3 to 7.3. Measurements of the catalysts activity, selectivity and stability indicate a strong dependency on the R-value. The yield of organic liquid C5-C11 increased from 17\xa0wt% to 59\xa0wt% while the yield of light olefins C2-C4 decreased from 60\xa0wt% to 14\xa0wt%, as R increased from 1.3 to 7.3. The content of C5-C11 iso-olefins and aromatics in organic liquid on ZnxZryOz (R\xa0=\xa03.9), WuZnxZryOz (R\xa0=\xa02.0) and MguZnxZryOz (R\xa0=\xa07.3) increased significantly with the residence time. ZnxZryOz was stable up to 360\xa0h on stream, while the activity and selectivity of MguZnxZryOz and WuZnxZryOz altered after 90\xa0h on stream due to coke deposition blocking the acid and basic sites. It was proposed a comprehensive scheme of ethanol transformations routes consistent with the measured effects of the residence time, catalysts R-value and time on stream on the products distribution.