Coal quality adaptability of Shanxi coal used in dry powder entrained-bed gasification

The coal quality conditions matched with the gasifier can make the the gasifier running smoothly and improve the gasification efficiency of gasifier.To improve gasification efficiency of dry powder gasifier,based on the technical requirements of dry powder entrainedbed gasification and relevant standards for coal quality classification,the coal quality characteristics of weakly caking coal in Shanxi Datong coalfield and lean coal and anthracite in Shanxi Qinshui coalfield were scientifically analyzed and evaluated. Coal quality adaptability of Shanxi coal used in dry powder entrained-bed gasification was studied. The results show that the coal in Shanxi is rich,and the coal in Shanxi for gasification is mainly distributed in Datong coalfield and Qinshui coalfield.The ash content of Hulonggou coal and Xiaoyu coal in Datong coalfield,Rundong coal in Qinshui coalfield are higher,and the dry-base ash content are 31.81%,35.59% and 42.17%,respectively.In coal gasification,the sulfur in coal is mainly in the form of hydrogen sulfide in gas,and a small part of sulfur remained in the ash.The sulfur-containing compounds would corrode gas transportation pipelines.The sulfur of Jinzhuang coal in Datong coalfield is relatively high,and the total sulfur content of dry base is up to 2.10%.From the classification of harmful elements in coal,the content of fluorine,chlorine,arsenic,mercury and phosphorus in coal for gasification in Shanxi is generally low,however the dry fluorine content of Rundong coal is relatively high,and the fluorine content of dry-base reaches up to 235 μg/g.At high temperatures tche fluorine in coal is decomposed into HF and a small amount of Si F4,CF4,etc.into the gas in coal gasification process.Therefore,it is necessary to reduce ash,sulfur and fluorine by washing processing before gasification.The most of Shanxi coal for gasification in the study were the medium and high ash fusion temperature coal,the softening temperature( ST) of Rundong coal was 1 340 ℃,and the ST and flow temperature( FT) of the remaining coal were all higher than 1 500 ℃.From the test results of the viscosity and temperature characteristics of coal ash,when the ash viscosity is 25 Pa·s,the corresponding temperature of Hulonggou coal ash is 1 445 ℃,and the corresponding temperatures of Xiaoyu coal ash,Tongxin coal ash and Tashan coal ash are 1 630 ℃,1 645 ℃ and 1 605 ℃,respectively.From the form of ash slag,the slag type of Hulonggou coal is glass slag,while the slag type of Xiaoyu coal,Tongxin coal and Tashan coal are crystal slag.The range of temperature operation may be narrow when the coal is used in entrained-bed gasification.Therefore,it is suggested that the slag viscosity can be changed by adding cosolvent,blending coal or washing processing.