Effect of heating rate and coal type on the yield of functional tar components

Pyrolysis with a rapid heating rate can be expected to achieve a higher yield of volatile matter than that with a slow heating rate. Therefore, this technique is attracting attention as a means to obtain useful liquid or gaseous materials in high yields. However, a detailed study on the tar components and increasing/decreasing yields of chemical materials involved in various-heating-rate pyrolysis has not been reported. Hence, in order to contribute to the advanced chemical applications of pyrolysis products, this study quantitatively investigated the effects of heating rate and coal type on the yield of functional coal-tar components using GC-MS. The main outcomes of the study are as follows: (1) The yields of cyclized aromatic hydrocarbons such as benzene, styrene, indene, naphthalene, and PAH (3- to 5-membered rings) increased with increasing heating rate. (2) A systematic method for obtaining the yields of functional coal-tar components was developed. The tar yield increased linearly with the H/C atomic ratio in various coal types. (3) The yield of indene, which can be used as a functional raw material, increased proportionally with increasing H/C ratio. The yield of fluorene, which can be used to enhance resin functionality, increased only for coals with a high H/C ratio.