1998 Volume 77 Issue 2 Pages 119-130
Secondary pyrolysis of coal tar produced from commercial coke oven was performed with a flow reactor at 700-900°C for 5-22 s and the effects of reaction conditions on the products yields and the composition of the light fraction has been investigated. The products were separated by solvent extractions into HS (hexane soluble), HI-CFS (hexane insoluble-chloroform soluble), CFI-THFS (chloroform insoluble-tetrahydrofuran soluble) and THFI (tetrahydrofuran insoluble=coke). The yield of HS decreased and that of THFI increased remarkably at 800 and 900°C. The HS fractions were analyzed by glass-capillary column gas chromatography equipped with a flame ionization detector. The HS fraction was made up of unsubstituted, alkyl-substituted and hydrogenated derivatives of polycyclic aromatic hydrocarbons (PAHs), heterocyclic and aliphatic compounds. It was found that the conversions of substituted PAHs and heterocyclic compounds containing oxygen and nitrogen, such as dibenzofuran and quinoline, increased remarkably at 900°C, and most part of these compounds disappeared in 13 s. Further, naphthalene which was considered as a most stable compound in unsubstituted PAHs in HS fraction also converted remarkably into the condensed compound at 900°C.