Liquid Phase Methanol Laporte Process Development

As part of the DOE-sponsored liquid phase methanol process development program (Contract No. DE-ACZZ-87PC90005), the present study (Task 3.8) evaluated adsorptive schemes to remove catalyst poisons from coal gas at pilot scale. In addition to a lab test with coal gas from Coolwater. two field tests were performed at Great Plains with live coal gas. In the lab test with Coolwater gas, iron carbonyl, carbonyl sulfide, and hydrogen sulfide were effectively removed from the coal gas. The capacities of H-Y zeolite and BPL carbon for Fe(C0)5 agreed well with the previous bench scale results at similar CO2 partial pressure. Significant Fe deposition was observed during regeneration. This was minlmfzed by regenerating at lower temperatures. COS appeared to be chemisorbed on FCA carbon; its capacity was non-regenerable by hot nitrogen purge. A CulZn catalyst, used to remove H2S adsorptively, worked adequately. With the adsorption system on-line, a downstream methanol catalyst showed stable activity for 120 hours of operatlon. In the two field tests, it was demonstrated that the Great Plains (GP) syngas could be treated by adsorption for LPMEOH process. The catalyst deactivation observed in the first field test was much Improved in the second field test after regular (every three days) regeneration of the adsorbents was practiced. The adsorption system, which was designed for the removal of ironlnlckel carbonyls, hydrogenlcarbonyl sulfide and hydrochloric acid, needed to be modified to accommodate other unexpected impurities, such as acetonitrile and ethylene which were observed during both field tests. A lab test with a simulated GP gas indicated that low CO2 content (0.5%) In the GP gas does not cause catalyst deactlvatlon. Adjusting the CO2 content of the feed to 5% by CO2 addition, increased methanol productivity by 40% in both the lab and the second field test.