Effect of properties of coal tar on quality of medium-temperature pitch

From the results of the analysis, the authors obtained the relationship between softening point, yield of volatile substances of the pitch and quality of the process tar. It is apparent that at low tar density under the existing plant conditions it is difficult to produce a stable medium-temperature pitch corresponding to GOST 10200-83. Only by increasing the density of the tar >1190 kg/m3 is it possible to produce a quality pitch, which is not always consistent with the interests of coke production. For this reason, additional heat treatment of the tar at 420-430°C and a pressure of 5 MPa is being planned at the Karaganda Steel Works to achieve stable production of high quality pitch according to TU 6-4-83. The technical conditions provide for the following indicators: softening point 87 ± 2°C, weight fraction of toluene-insoluble substances 33-37%, weight fraction of quinoline-insoluble substances 8-12%, yield of volatiles 51-55%.