Pyrolysis of lignites and brown coal catalytically depolymerized with phenol to produce anisotropic coke or light oil

Pyrolysis of lignites and brown coal catalytically depolymerized with phenol was studied in order to design easy liquefaction or up-grading procedures effective under non-extreme conditions, where the recovery of phenol may be critical. The lignites were solubilized in pyridine very easily at low phenol/lignite ratios, but high ratios were required to induce their solubility in benzene-ethanol or THF. Although THF- and pyridine-soluble (abbreviated as THFS and PS, respectively) fractions exhibited fusibility in their single carbonization to produce grain cokes of optical isotropy, optical anisotropy can be developed by co-carbonization with petroleum pitches, suggesting that these fractions may be suitable as needle or blast furnace coke sources. The heat-treatment of PS with a hydrogen donor made it completely soluble in benzene. The recovery rates of bound phenol in the depolymerized lignite were at highest 57 and 36%, respectively, for the coking and heat-treatment processes, although the formation of alkyl phenols may occur in the heat-treatment.