Study On The Influence Of Coking Coal Moisture On The Coking Process And Coke Quality Of Dry Coal

Coal moisture control technology has been developed rapidly in China,which has the advantages of significantly reducing coking heat consumption,increasing coke oven production capacity,improving coke quality,increasing the proportion of weak caking coal,stabilizing coke oven operation and reducing sewage emissions.However,China's coal moisture control technology started late and lags behind Japan.Japan has used the DAPS process and uses dry coal for coking.Therefore,by studying the effects of moisture on the plastometer indices and coke quality and developing dry coal coking technology with independent intellectual property rights are significant to break the technological monopoly of the Japanese DAPS process.First,the experiments of measuring the plastometer indices of coking coal under different moisture contents were carried out,and the influence of moisture on the caking property,swelling property and volume change of coking coal were discussed.Then the cokes were prepared under different moisture contents by using a 5 kg experimental coke oven.The influence of moisture on coke quality and coking mechanism of dry coal were discussed by testing cold strength,thermal properties,optical texture and surface morphology of coke.Finally,the effects of heating system,i.e.coking final temperature,holding time and heating rate,on the cold strength,thermal properties and microcrystalline structure of coke from dry coal coking were discussed,and the coke quality was effectively improved by optimizing the heating system.At the same time,the optimal heating system for coking of dry coal in the laboratory was determined.And the obtained main results are as follows:?1?Moisture has a certain effect on the plastometer indices of coking coal.As the moisture content of coking coal increases,the final shrinkage is significantly increased,and the maximum thickness of the plastometer indices is basically unchanged.The effect of moisture on the cohesiveness of coking coal is small,but it has a certain effect on the coking process of coking coal.?2?As the moisture content of blending coal increases,the quality of coke deteriorates.The M₂₅ of coke was reduced from 85.4%to 82.5%,the M₁₀ of coke was increased from 10.6%to 13.4%,the CSR of coke was reduced from 50.2%to 46.3%,and the CRI of coke was increased from 35.5%to 39.2%.The moisture content of coking coal can affect the heating process of the coal,the content of the optical texture of the coke,and the microstructure of the coke.As the moisture content increases,the heating rate of the coal material becomes slower,the final temperature in the center of the coke cake decreases,the degree of anisotropy of the coke decreases,and the pores of the coke become larger and more.?3?The coke quality is effectively improved by optimizing the heating system.With the increase of coking final temperature,holding time,and heating rate,the microcrystalline layer spacing d₀₀₂ of the coke is decreased,the degree of graphitization is increased,and the coke structure strength is increased.The optimal heating system for coking of dry coal in the laboratory:the coking final temperature,holding time and heating rate of coking are 1150?,2.5 h and 2.5?/min respectively.