STEX PROCESS - EXTRACTION OF STYRENE FROM PYROLYSIS GASOLINE.

Abstract

Styrene in pyrolysis gasoline produced in ethylene plants is recovered by this process which consists of extractive distillation with a special solvent. The total yield of styrene from a recently constructed ethylene plant (300,000 to 500,000 t/yr) goes up to 15,000 to 30,000 t/yr. At the same time, xylenes from pyrolysis gasoline are graded up by the decrease of ethylbenzene content which is usually enriched by hydrogenation of styrene. Besides extractive distillation, the STEX process has many distinctive features such as chemical purification and polymerization inhibition method. The STEX process which can be easily attached to an ethylene plant without any significant flow alterations will make great contributions to rationalize the plant by avoiding the waste of energy and resources.