Chemistry and Mechanism of Molten Salt Catalysts in Coal Gasification Processes. Final Report January 1984 - January 1985

摘要

Alkali metal salts have been recognized as effective catalysts in coal gasification. However, the presence of reducing gases, in particular carbon monoxide, has recently been shown to have serious inhibitory effects on the catalyst performance. This program has addressed the question of the chemical interactions between carbon monoxide gas containing mixtures and the salt catalysts in liquid form by probing the solution chemistry by dynamic electrochemical techniques. The results of this study show that oxalate ions are formed by the reaction between carbonate ions and carbon monoxide gas. At temperatures above 700 degrees C, sulfate ions are directly attacked by carbon monoxide. The oxalate ions are electroactive and their electrochemistry has been studied and found to involve adsorption of oxalate and formation of reactive intermediates. The pathway likely involves an ECE sequence. The formation of active adsorbed species such as oxalate or sulfides at high temperature may be the means by which catalytic function of the salts is inhibited.