Fischer-Tropsch Synthesis: Influence of CO conversion on selectivities, H2/CO usage ratios, and catalyst stability for a Ru promoted Co/Al2O3 catalyst using a slurry phase reactor

Abstract

The Co particle size effect is a topic of interest in Co-based Fischer-Tropsch synthesis catalysis. The effect of CO conversion on various parameters, i.e., CH 4 and C 5+ selectivities, CO 2 selectivity, H 2 /CO usage, and olefin/paraffin, was studied. CH 4 selectivity decreased and C 5+ selectivity increased with increasing CO conversion. When CO conversion was over 70%, the decrease in CH 4 selectivity and increase in C 5+ selectivity decelerated. CO 2 selectivity started to increase rapidly at ˜ 70% CO conversion for the Ru-Co/Al 2 O 3 catalyst. Controlling CO conversion below 70% for long-term testing of Co/Al 2 O 3 catalyst possibly minimized CH 4 and CO 2 selectivities and extended catalyst life. The H 2 /CO usage ratio decreased from 2.26:1 to 1.9:1 when CO conversion increased from 12% to 94% at a H 2 /CO feed ratio of 2.1:1. The decreasing H 2 /CO usage rate with CO conversion was ascribed to an increase in the WGS rate. This is an abstract of a paper presented at the 2011 AIChE Spring Meeting & 7th Global Congress on Process Safety (Chicago, IL 3/13-17/2011).