Abstract: The separation of styrene from pyrolysis C8 fraction by extractive distillation, using N,N-dimethylacetamide as solvent, was studied by process simulation and pilot test. The effects of solvent ratio, reflux ratio, plate position of solvent feed and temperature on the purity and yield of styrene were investigated. The results showed that the styrene product purity can reach more than 99.8%，styrene recovery rate of 98.5% or more at the conditions of the feed plate position in the range of the 11th to 13th, the solvent ratio of 3.8-4.2, the reflux ratio 3.1-3.3, the solvent temperature 45-50 ℃. The pilot test results are consistent with the process simulation, proving that the process simulation system is reliable. Compared with the extraction distillation process by using sulfolane solvent, the operating temperature of the tower using N,N – dimethylacetamide solvent is only 113 ℃, beneficial to the long operation of the device.

Key words: pyrolysis gasoline, extraction distillation, styrene, N,N - dimethylacetamide