Study On Physicochemical Characteristics Of Slag From Entrained-flow Coal Gasification

Studying on the physicochemical properties of gasification slag has great significance in improving the efficiency and stability of the gasifier.This paper comprehensively studied the physical and chemical characteristics of different slags collected from powder coal gasification furnace,coal water slurry gasifier,water coke-coal slurry gasification unit,such as coarse slag,fine slag,fly ash and unnormal slag from SE gasifier.Slags generated from different gasifier,under different conditions from SE gasification unit has been researched.And with the physical and chemical properties of coarse slag and fine slag in different particle size was tested,different forms of gasification ash particles are classified which constitute most forms of slag.These ash particles of different forms were corresponded with particular experiences in the gasifier during gasification process,which subsequently lead to difference in residual carbon content,mineral composition.Properties of raw coal,the gasification process,the operating conditions and other factors determine the content and distribution of different forms ash particles in coarse slag and fine slag,thus determine the carbon residue content,particle size distribution,macro morphology characteristics of gasification slags.The comparison study of physicochemical properties of slag,it is concluded that petroleum coke-coal gasification slag has a higher residue carbon content and larger particle size than slag of coal gasification.This is mainly related to the basic property of petroleum coke as its coal-coke slurry.The physicochemical properties of ash and slag in the SE gasifier were analyzed.The fine ash in the gasifier is entrained by the syngas into the washing system and is deposited in the equipment to form dense deposition mass of slag.The residual carbon content and ash chemical composition of ash from different equipment were similar to that of fine slag.The enrichment of different slag in different devices can be explained by the difference of its residual carbon and composition.The formation of the slag is mainly due to the poor slagging of the gasifier and the difference of ash composition and its fusion characteristics between the single coals in the mixed feeding coal.And these fiber slag is prone to hold some coarse slag and fine ash particles together because of its adhesive properties.