Sulfur removal from Texas lignite using steam and air

Abstract

The objective of this work was to develop a method to remove sulfur from Texas lignite using steam and air. Batch experiments were performed in small 80cc reactors using lignite from the Wilcox formation. The experiments were conducted at temperatures from 300 to 450°C, at pressures from 0.67 atm to about 35 atm and for several lignite/water/air ratios. The results showed that sulfur reduction in the range of 45 to 50% can be obtained at reactor conditions of about 450°C, 1.7 atm and residence times of about 15 to 20 minutes. Analytical tests showed that the sulfur reduction was primarily of the organic form. This process could be combined with a prewash for minerial matter and partial pyrite removal to give total sulfur removals of from 60 to 70%.