Patent ID: 6504071
Filing Date: 2003-01-07
Classification: C07C,Y02P,Y10S

Abstract:
A process for the preparation of ethylbenzene by alkylation of benzene with dilute ethylene contained in a refinery dry gas by catalytic distillation, which is carried out within a catalytic distillation tower comprising a reboiler, a stripping section, a reaction section, an optional rectifying section, and a top condenser, which process comprises1) pre-treating a raw refinery dry gas by, if necessary, pressure adjusting, desulfurization and dehydration, resulting in a pre-treated dry gas; 2) feeding the pre-treated dry gas into a catalytic distillation tower at a position below the reaction section, and feeding benzene into the tower at its top, or splitting benzene feed into several streams and feeding them into the tower at its top and at different positions of the reaction section, the total molar ratio of total benzene to total ethylene being in the range of 5-20, and the molar ratio of benzene/ethylene in the fresh benzene and dry gas feeds being 1-3; keeping the benzene and dry gas feeds countercurrently flowing in the tower and reacting with each other inside the reaction section which is packed with a bed of catalyst particles and distillation packing, and simultaneously separating in the reaction section the resulting mixture of reactants and products by distillation; drawing out of the tower the top overhead and the bottoms comprising product ethylbenzene; condensing vaporized benzene in the top overhead in the top condenser; and recycling the condensed benzene to the tower; 3) wherein the reaction section packed with catalyst particles and distillation packing meets the following conditions: (a) the catalyst used satisfies: evaluated ethylene conversion &gE;95%, and evaluated ethylbenzene selectivity &gE;95%; (b) the separating efficiency of the reaction section satisfies: &gE;0.5 theoretical stage per meter of measuring tower (catalyst particles+distillation packing); and (c) the bed voidage of the reaction section is &gE;70%.