Experimental Study On Lignite Thermal Upgrading And Releasing Characteristics Of Sulfur-Containing Gases

Coal is the most important energy resource in China, and lignite is an important part ofcoal. As high rank coal is less and less, it had been a hot research topic to find ways toutilize lignite in an efficient way with less pollution.As a kind of high fluid and volatilitycoal, lignite char can achieve the rank of bitumite through mild thermal upgrading. Besides,sulfur in coal can be removed with little heat value loss in the process of pyrolysis underproper control of atmosphere,time and tempreture.Two lignite samples from Shengli in Inner Mongolia and Zhaotong in Yunnan werechosen to put research on.It had been studied that the way how conditions during upgradinginfluce the effcet of upgrading which contains char productivity, calorific value and theremain ratio of volatiles.At the same time,it als had been studied that the desulfurizationdegree and the regular patten of release of sulfurous gas.Researches in this study were put on in both tube furnace and fluid-bed, in this way,results of the way how conditions during upgrading influce the effcet of upgrading can bedisscussed separately. Studies confirm that as the tempreture grows,the productivitydecreases,the heat value increasesand the remain ratio of volatiles falls off sharply whentempreture is above400℃.Low-oxidizing and low-organic atmosphere can promote therelease of sulfurous gas.Proper reaction time can get a better outcome of upgrading.Toolong reaction time may not improve the effect of desulfurization, on the contrary, it maydecrease the char productivity and the calorific value. For each lignite sample from Shengliand Zhaotong,the proper tempreture is400℃and350℃,and the proper reaction time isboth20mins.In fluid-bed condition,5mins is long enough for upgrading. Contrast toexperiment put on the tube furnace, reaction in fluid-bed conditions need less time to finishthe process of mild thermal upgrading.