The Establishment Of A Method For Determination Of Plastometric Indice Under The High Bulk Density And Its Application In Coke Quality Prediction

The process of stamp-charged coking as a kind of coking technology,which has the advantages of the high proportion of weak caking coal,the low cost of coal blending and the high cold strength of coke,has been rapidly developed in China.By around2025,the capacity of stamp-charged coking is accounted for fifty percent of the total capacity of coke.At present,the study on stamp-charged coking mainly concentrated in the influences of the amount of weak coking coal and the density of coking coal on coke quality.But the study on the effects of bulk density on caking property and swelling property of coking coal in the coking process is not deep enough.Therefore,the further research on the effects of bulk density on the caking property,swelling property and volume change of coking coal is significant to expand the resources of coking coal,to optimize coal disposition,to prolong the service life of coke oven,to ensure stable production of stamp-charged coking and so on.First,the 5 kg coking experiments of the single coal were carried out in the laboratory,and the effects of bulk density of single coal on the ash,sulfur,porosity,cold strength and thermal performance of the coke were analyzed comprehensively.Then the determination method of plastometric indices for the bituminous coal was improved to measure the plastometric indices of the coals under the different bulk densities.And the effects of bulk density on caking property,swelling property and volume change of single coal were discussed.Then a series of coal blending schemes were developed by combining the data obtained above and the coal petrography blending theory.The stamp-charged coking experiments were carried out in the 5 kg coking oven and the cold strength and thermal property of the coke samples were measured.Finally,based on multivariate linear regression analysis,the V_daf-G-Y_d coke quality prediction model under tamping density condition was established with the dry ash-free volatile matter content?Vdaf?,caking index?G?and tamping maximum thickness of plastic layer?Y_d?of different blending coals as independent variables as well as the cold strength indexes?M10,M25?and thermal properties indexes?CRI,CSR?of different cokes as dependent variables.At the same time,the F tests and error analysis were performed on this prediction model.And the obtained main results are as follows:?1?By improving the determination method of plastometric indices for the bituminous coal,the plastometric indices of the different coking coals,which is measured under the high bulk density,can more accurately reflect the caking property,the swelling property and the volume change of coking coal under the corresponding bulk density.?2?High density can improve the caking property of gas coal,1/3 coking coal,fat coal and coking coal to a certain extent.And the improvements of gas coal,1/3 coking coal and coking coal are better than fat coal's improvements.The improvement of lean coal is not obvious,it almost can be ignored.?3?Compared with the traditional V_daf-G-Y_d prediction model,the V_daf-G-Y_d prediction model has a better prediction accuracy,the relative errors of the predicted CRI,CSR and M25 decrease by 15.3%,20.7%and11.9%,respectively.