Study Of Effect Of Modified Coal-tar Pitch On Coking Property Of Poor Coking Coal

Although the reserve of coking coal resources of our country is complete, the amount of high-quality coking coal resources is poor. The basic structural unit of coal tar pitch is similar to coal, it can improve the coal coking properties of raw material when add the coal tar pitch to blending coal, which can increase the use of weak caking coal and reduce the ratio of high-quality coking coal. So it’s meaningful to research the influnce of different process conditions of modified pitch on inferior coking coal.This paper takes the mid-temperature pitch as the research object, modificates pitch at different temperature and different conditions. Then add the different kinds of modified pitch respectively into Jinjian gas coal, Tiankun 1/3 coking coal and Zhongwei lean coal at a ratio of 5%, and determinate the coke’s microstrength, structure strength, thermal properties and optical organization, analyze the influence of different modificated conditions on the changes of different kinds of pitch, and the properties of the coke. The results show that: softening point and coking value of modified pitch are on the rise with the increase of modification temperature and modification time, volatile showed a trend of decrease; Both of toluene insolubles and quinoline insolubles content show a trend of increase, the highest reached 43.8% and 21.4%, but the content of toluene insolubles increases smoothly, and quinoline insolubles content increases slowly before 390℃, the content of quinoline insolubles increase sharply at the point of 420℃; Firstly the content of βcomponents increases and then decreases, the inflection point is 390℃, reached 27.8%; Three single kind of coal caking index are improved obviously after adding the modified pitch into the coal, and at the same modification time, the caking indexes of the coal increase before 390℃ and then decrease, under the condition of 390℃ of modified pitch has the best modification effect to coal, caking indexes increased 9,10 and 17; After adding the modified pitch into the coal, the coke optical organization ∑ISO all decrease. Through thermal modification can improve the performance of asphalt as a blending caking agent, but the polymerization temperature cannot be exorbitant, otherwise the content of quinoline insolubles will increase rapidly, result in the decrease of effect by modified pitch to caking property, thermal modification temperature should be controlled under 400℃.