Bituminous Coal Pyrolysis Tar as Feedstock for Carbon Black Production -A Preliminary Study

摘要

A steadily decreasing metallurgical coke production in by-product coke ovens inthe U. S. vis- à- vis the strong demand for coal tar and coal-tar derived carbon precursorscalls for exploring acceptable alternative presses to separate coal tar production fromthe parent press of coke-making in by-product coke ovens. As a possible alternative,steam pyrolysis of bituminous coals was proposed for the production of raw coal tar,which can be further pressed to produce coal tar products with desired properties. Inthis study, steam pyrolysis of four different coal samples (Arch, Amerikohl, Splash damand Pahontas #3) was carried out in a tubular reactor. Steam pyrolysis experimentswere conducted at four different temperatures (500, 600, 700 and 800°C) on all thesamples using a steam flow rate of 3g/min at a constant heating rate of 10°C/min. Theeffects of heating rate and steam flow rate on the product yields and were also studied fordifferent coal samples. Changes in pyrolysis temperature, heating rate, and steam flowrate strongly affected the tar yields and composition. In general, an intermediatepyrolysis temperature (600°C), an intermediate steam flow rate (3 g/min), and a moderateheating rate (10°C/min) gave the highest tar yields. Among the coal samples,Pahontas #3 gave a much lower tar yield (3-5% wt on a dry-ash–free basis) than thoseof the other samples that ranged between 7 and 16 wt% on daf basis. These tar yields aremuch higher than that obtained in by-product coke ovens (2-3%).The tar samples obtained were characterized by high-temperature simulateddistillation using gas chromatography (HT Sim-Dis GC) with a capillary column. The