The Study Of Plastic Properties Of Coking Coal With Low-rank Coal Macerals

Owning to the shortage of high quality coking coal resources and the advantages of low rank coal of low ash, low sulfur and cheap, coking with low rank coal will become an unstoppable trend. Coal pyrolysis to produce colloid substance is the important stage in the process of coking, the bond property and coking property of coal depend on the quantity and characteristic of the colloid substance which produces by the coal pyrolysis.This article adopted the method of density gradient centrifugation to separate the coal and its macerals, and at the same time to consider the productivity of vitrinite separation and enrichment. The result of bond index experiment found that bond index of the vitrinite of weakly caking was 43.3, the inertinite of weakly caking coal and the macerals of long flame coal have no bond property. Followed further study on pyrolysis laws of experimental coal sample and its microscopic components by infrared analysis experiment.Respectively blended the coking coal with 2%, 4%, 8%,12% of low rank-coal macerals, studied on the influence law of the low-rank coal macerals to the quality of coking coal colloid. Indirect determination method including bonding index G value and the improved test methods of the bituminous coal caking index for GI value. G value determined with reference to national standard, GI method puts forward coke powder instand of anthracite. The mothed mainly study the ability to accommodate inert material influnce law of different proportion of low rank coal or its maceral on bituminous coal. Direct determination method includes direct determination of colloid dilatation, colloid viscosity and fluidity of the body, the experiment respectively and the experiment expansion and gieseler fluidity.Studing the law of colloid body influence of low rank-coal macerals on main coking coal showed: with the gradual increase of the proportion of the low rank coal,the expansion degree of the combined coal decreased, and thegas permeability of the colloid substance enhanced, the expansion influence of the vitrinite of weakly caking coal on the coking coal is positive.The mixing coal whole flow degree reduced, the decrease in the number of colloid substance, the temperature range of mixing coal narrow, the thermal stability of mixing coal going down, colloid substance quality becomes poor. The low rank coal has a whole decrease in the fluidity of coking coal,the least effect on the fat coal, a larger effect on gas coal and coking coal, Butunder the condition of same percentage the weakly caking coal vitrinite has minimum impact on the main coking coal. And the coal soft solid temperature range is narrow,and the thermal stability of the blended coals' colloid substance is also changed,That the quality of colloid substance of the blended coals have decreased in varying degrees.In addition,studying the bonding index G value and GI value of the coal sample we know: compression molding is advantageous to the coherence between coal particles,the bond property of gas coal or coking coal with low-rank macerals is a linear law; However, because of fat coal caking property is strong, When equipped with the proportion of low rank coal macerals is greater than 8% the G value and GI value of fat coal are significantly reduced.