Project for laboratory study for removal of organic sulfur from coal. Quarterly technical progress report

The Gravimelt Process was extended to the desulfurization of ordinary mine-cleaned Kentucky No. 11 coal obtained from the Tennessee Valley Authority. Eight process runs were made resulting in reduction of the sulfur content from a starting 2.7 lbs S/10/sup 6/ Btu to a mean of 0.475 lbs S/10/sup 6/ Btu, (0.95 lbs SO/sub 2//10/sup 6/ Btu) for an average 82% sulfur reduction. The effect of utilization of molten sodium hydroxide alone vs molten mixed potassium and sodium hydroxide was investigated for this coal; sulfur reduction averaged 84% for the mixed melt and 78% for the use of sodium hydroxide alone. A double extraction with sodium hydroxide resulted in a reduction in total sulfur to 0.3 lbs S/10/sup 6/ Btu which is an 89% reduction. In a series of experiments, the melt was reused three times on fresh samples of coal, always giving the same amount of sulfur reduction. Extraction of the desulfurized Kentucky No. 11 coals with an additional dilute sulfuric acid wash reduced the ash content of the coal from 7.9% to a level of 0.3%, thus providing a solid hydrocarbon fuel similar in both ash and sulfur content to a medium grade fuel oil. Multiple experimentation on high ash Kentucky No. 9 sink coal demonstrated that water washing alone reduces the sum of sodium and potassium retained on the coal the the level of the starting input coal or to a level of approximately 1% total alkali metals. Thus, retention of alkali metals by Gravimelt treated coal will not be a problem