| 摘要 |
Combined process for ethylen prodn. in which (a) a normally-liquid hydrocarbon fraction is passed with excess H2 through a catalyst-free thermal hydrocracking zone under conditions which give a product free from non-aromatic hydrocarbons with more than 3C atoms; (b) a hydrocarbon stream contg. 2 or 3C atoms is separate by low temp. processes, (c) the stream is passed to a cracking zone and converted mainly to ethylene, adn (d) the unreacted hydrogen from (b) is recycled to (a). The hydrocarbon stream from (b) pref. consits mainly of ethane and/or propane. Conditions in (a) are such as to produce virtually no saturation of the aromatic component, which is separated from the product and fractionated to produce pure benzene. Liquid hydrocarbon fraction are converted to almost pure ethane and/or propane streams suitable for use in existing on-line cracking plants, with benzene and natural gas substitute as by-products. |
