The role of catalyst precursor anions in coal gasification. Sixth quarterly report

Abstract

This project seeks to understand the roles of various aqueous soluble catalyst precursor anions, specifically acetate (CH{sub 3}COO{sup {minus}}), chloride (Cl{sup {minus}}), nitrate (NO{sub 3}{sup {minus}}), sulfate (SO{sub 4}{sup 2}{sup {minus}}) and carbonate (CO{sub 3}{sup 2}{sup {minus}}) anions on the surface electrical properties of coal and to ascertain the effects of the surface charge on the adsorption, dispersion and activities of calcium and potassium. In the foregoing quarter, the effects of nitrate anion on the surface electrochemistry of the demineralized samples of the coal (North Dakota lignite, PSOC 1482) has been conducted using calcium or potassium nitrates. Demineralization increased the negative surface charge density on the coal compared to that on the original unleached sample. However, addition of Ca(NO{sub 3})2 or KNO{sub 3} reduced the negative charge density, the effect is more pronounced with increase in the precursor concentration due to the adsorption of the metal ion onto the coal surface. These results were confirmed by metal adsorption studies, as reported in a previous report. Surface area measurements using nitrogen adsorption and the BET equation shows a 50% reduction in the surface area compared to that of the original coal. This phenomenon is attributed, primarily, to the removal of finely divided, high surface area siliceous materials from the coal.