Abstract:

The changes of Y value,volume curve of gelatinous layer and X value of five individual coals under different bulk density are studied.The result shows that when the bulk density is increased from 0.75t/m3 to 1.2t/m3,Y value of gas coal,1/3 coking coal,fat coal and coking coal increases by 2.5mm,5.0mm,6.3mm and 5.8mm respectively,while there is no significant increase for lean coal; the volume curve of plastic layer for 1/3 coking coal changes from zigzag mountain type,which indicates that with the increase of bulk density,the plastic layer property of 1/3 coking coal is similar with that of fat coal,while the plastic layer property of gas coal,fat coal,coking coal and lean coal doesn’t change too much;X value of all the five individual coals decreases obviously with the increase of bulk density,and gas coal,1/3 coking coal fat coal and coking coal show obvious positive expansion during coking process.