| 摘要 |
Prodn. of methyl tert.-butyl ether (MTBE) and a premium gasoline, starting essentially with 4C fractions contg. at least 30 wt.% of (isobutane + n-butane) comprises: (a) feeding such a fraction or a fresh feedstock, after removing H2O, S and N, to vapour phase dehydrogenation, with prodn. of isobutene, n-butene and 1,3-butadiene; (b) cooling the effluent gas from (a) by heat exchange with fresh feedstock; (c) fractionating the cooled effluent from (b) to give a gaseous fraction (1), rich in H2, CH4 and C2H6, which is largely recycled to (a), a C3H8-contg. fraction (2), and a fraction (3), contg. esp. n- and isobutane, n-butenes, isobutene and 1,3-butadiene; (d) leading fraction (3) to an etherification zone with 1-10 moles MeOH per mole isobutene, which is thereby largely converted to MTBE; (e) fractionating the effluent stream from (d), giving a fraction (4), contg. most of the unreacted MeOH, which is largely recycled to step (d), a fraction (5), contg. most of the MTBE formed, in nearly pure form, and a fraction (6), contg. esp. n- and isobutane, n-butenes and 1,3-butadiene, with traces of MTBE and MeOH; and (f) feeding fraction (6), possibly after redn. of its MeOH content, to alkylation, for reaction of isobutane and butenes to give an alkylate, representing a premium gasoline component. |
