Characteristics of migration and enrichment of elements during coal water slurry gasification
The migration and enrichment characteristics of elements have a significant impact on the long-term stable operation of coal gasification plants.The samples(the raw coal and the coarse and fine slag after gasification)collected from entrained-flow coal water slurry gasification plants were studied using X-ray diffraction(XRD)and X-ray fluorescence spectrometer(XRF).It is found that elements such as Na,P,V,and Ti were more easily enriched in the fine slag,while elements such as Fe,Ca,and Cr were more easily enriched in the coarse slag.The thermodynamic calculation results indicated that the V element mainly existed in the form of gaseous V2O3 or VO2 during the gasification process;at high temperatures,the S element basically transformed into volatile forms such as gaseous COS and H2S,with little residue in both coarse and fine slag.During the heating process,Cr element mainly combined with Mg and Fe to form solid phase MgCr2O4 and FeCr2O4.After reaching about 1100℃,it was more likely to exist in the form of CrO and Cr2O3 in the liquid slag.A weak reducing atmosphere was carried out in a tube furnace to explore the influence of temperature on the enrichment of elements in coal ash.The results showed that the higher the gasification temperature,the easier Na and S elements were enriched in the gas phase,while Ca,Fe,and Cr elements were enriched in the slag.
coal water slurrycoal gasificationmigrationenrichmentthermodynamic
万方数据
维普
