The Experimental Research Of Formed Coke Preparation Using Low Rank Pulverized Coal And Tar Slag

The resources of low rank coal account for42.5%of all the coal reserves in China,a large part of them are the pulverized coal. Along with increase of mechanizationdegree and lump coal yield, pulverized coal also increased rapidly. At present, most ofpulverized coal is used for burning. It leads to lower thermal efficiency, the waste ofresources and pollution of mining environment. The tar slag rich in coal tar is producedduring the low-temperature carbonization, which is not easy to process and results inlow tar yield. Therefore，it is urgent to resolve the tar slag and low rank pulverized coaldisposal promble.This paper reasearches the preparation of formed coke using low rank pulverizedcoal from Shanbei. It mainly discussed the effects of inorganic binder, organic binderand composite binder, tar slag and coking coal. The influence on formed coke quality ofmolding process and carbonization process are also studied. Then it analyses thebonding mechanism and pyrolysis mechanism of formed coke. The major conclusions ofthis research are as follows:The experiment shows that bentonite has the best bond behavior among inorganicbinders. The optimum ratio is5%bentonite,9%coking coal,1%tar slag. Thecompressive strength formed coke is1300N/ball. The alkalization of starch in theorganic binder has more stable bonding property. The best ratio obtaining fromorthogonal test is as follows:5%alkalization of starch,10%coking coal,5%tar slag.The formed coke with compressive strength2290N/ball and drop shatter40.2%aregained.The optimum process condition is5%alkalization of starch,3%bentonite,8%coking coal,4%tar slag for preparation of formed coke using composite binder. Thesize of low rank pulverized coal<0.63mm, the size of coking coal<0.28mm, formingpressure60kN, moisture content12%; The optimum carbonization process condition is: final temperature of carbonization700℃, heating rate5℃/min. The formed coke withcompressive strength2910N/ball and drop shatter50.1%is produced using the aboveconditions. It is closed to the qualification of blue coke.