Experimental study on the water medium gravity separation of gasification slag and the preparation of desulfurization and denitrification activated coke using separated carbon

In this study,the basic physical properties of the gasification fine slag produced by the GSP dry powder gasifier at Ningxia Coal Industry Co.,Ltd.,the National Energy Group were analyzed for particle size composition and density composition.The water medium gravity separation was carried out by using a complicated cone water-medium cyclone with a compound cone structure.The product ash,yield and carbon distribution rate were used as evaluation indicators.According to the structural parameters and operating parameters obtained from the preliminary condition test,through the gravity separation of water medium,three types of products can be obtained including carbon-rich product,ash-high product and ash-rich product.The yield of carbon-rich products is 8.37% and the ash content is 12.69%,the carbon content is 51.62% higher than the original slag;the yield of high-ash products is 24.36% and the ash content is 95.68%;the total carbon recovery rate of carbon-rich products and high-ash products reaches 97.09%,achieving an efficient separation and enrichment of residual carbon and ash.The difference in the apparent density and selectivity of the products verifies the feasibility of gravity separation of water media.The SEM-EDS energy spectrum analysis,BET pore structure analysis,XRD test,etc.were performed on the original sample and the three types of products.Most of the carbon-rich products are irregular porous flocs with high specific surface area and pore volume.The total specific surface area is 287.82 m2/g,and the microporous specific surface area is 155.89 m2/g,which has the potential to be a raw material for activated coke.Using carbon-rich products as raw materials,adding a certain ratio of coking coal,long flame coal,tar,pitch and other raw materials,based on the ratio of different coal types in the early stage and the interaction mechanism in the pyrolysis process,the activated coke was obtained by the coal blending method,its wear resistance reached 97.00% when the carbon-rich products was 50%.The compressive strength was 498.5 N.The desulfurization and denitrification performance of the prepared gasification slag-based activated coke was evaluated with reference to the requirements of the national standard.The desulfurization value was calculated to be 32.63 mg/g,which is much higher than the standard requirement,and the denitration rate is 27.50%.