Conversion of Sulfur in a Reducing Environment

Sulfide formation in a reducing atmosphere was studied on a fluidized bed test rig.Test results show that,under reducing conditions,most of the sulfur in the fuel is converted first into H_2S,while only a small proportion is being converted into SO_2,which,the author believes,originates from the decomposition of sulfate.The amount of H_2S formed is greatly influenced by the reducing atmosphere,the proportion of organic sulfur,as well as the amount of oxygen present,which means that the stronger the reducing atmosphere,the higher the proportion of organic sulfur content and the lower the oxygen content,the more H_2S will be produced;H_2S formation rate depends both on the volatile matter and the organic sulfur content in the coal,i.e.the higher the volatile content and the lower the organic sulfur content,the earlier H_2S will appear.Simple sulfur is easily formed in strong reducing atmospheres originating from coals containing little volatile matter and low in organic sulfur content.Therefore during desulfurizing processes,in circulating fluidized beds effective measures should be taken to remove H_2S generated during the combustionof coal,especially in case its sulfur content being high.Figs 6,tables 2 and refs 12.