TITLE: Kinetic study of methanol synthesis in a slurry reactor using a CuO/ZnO/Al(sub 2)O(sub 3) catalyst.

AUTHOR: H. A. Al-Adwani.

INST.  AUTHOR: Texas A and M Univ., College Station.

SPONSOR: Department of Energy, Washington, DC.


PUB.  TYPE: Thesis

PUB.  COUNTRY: United States

SOURCE: Department of Energy [DE],  May 92,  107p.



A kinetic model that describes the methanol production rate over a CuO/ZnO/AI(sub 2)0(sub 3) catalyst (United Catalyst L-951) at typical industrial operating conditions is developed using a slurry reactor.  Different experiments are conducted in which the H(sub 2)/(CO+CO(sub 2)) ratio is equal to 2, 1, and 0.5, respectively, while the CO/CO(sub 2) ratio is held constant at 9. At each H(sub 2)/(CO+CO(sub 2)) ratio the space velocity is set at four different values in the range of 3000-13,000 1/hr kg(sub cat). The effect of H(sub 2)/(CO+CO(sub 2)) ratio and space velocity on methanol production rate, conversions, and product composition is further investigated. The results indicate that the highest methanol production rate can be achieved at H(sub 2)/(CO+CO(sub 2)) ratio of 1 followed by H(sub 2)/(CO+CO(sub 2)) ratio of 0.5 and 2 respectively. The hydrogen and carbon monoxide conversions decrease with increasing space velocity for all H(sub 2)/(CO+CO(sub 2)) ratios tested. Carbon monoxide hydrogenation appears to be the main route to methanol at H(sub 2)/(CO+CO(sub 2)) ratio of 0.5 and 2. On the other hand, carbon dioxide hydrogenation appears to be the main route to methanol at H(sub 2)/(CO+CO(sub 2)) ratio of 1. At all H(sub 2)/(CO+CO(sub 2)) ratios, the extent of the reverse water gas shift reaction decreases with increasing space velocity. The effect of temperature on the kinetics is examined by using the same experimental approach at 508 K. It is found that a different reaction sequence takes place at each temperature. Also, a time on stream study is conducted simultaneously in order to investigate the characteristic of catalyst deactivation with time on stream. During the first 150 hours of time on stream, the catalyst loses approximately 2/3 of its initial activity before reaching a steady state activity.