Patent ID: 6953872
Filing Date: 2005-10-11
Classification: C07C,C10G

Abstract:
1. A process of producing C 2 - to C 4 -olefins from steam and a feed mixture containing C 4 - to C 8 -olefins, wherein the feed mixture containing steam is introduced into a reactor with an inlet temperature of 300 to 700° C., said reactor comprising a bed of granular, form selective zeolite catalyst, wherein a product mixture containing steam and C 2 - to C 4 -olefins is withdrawn from the bed and in passed through at least one cooling means, characterized in that the vaporous product mixture coming from the cooling means ( 6 ) is pressurized and the pressure of the product mixture is increased by 0.3 to 7 bar, that the pressurized product mixture is passed through an indirect heat exchanger ( 15 ) and the product mixture is cooled therein to such an extent that a water-rich condensate is produced by releasing heat of condensation, that the product mixture containing condensate is introduced into a separator from which a water-rich condensate and, separate therefrom, a vaporous product mixture containing C 2 - to C 4 -olefins is withdrawn that water-rich condensate coming from the separator is expanded and evaporated in the indirect heat exchanger by utilizing the heat of condensation previously released during condensation, that at last part of the steam is introduced from the indirect heat exchanger into a mixing chamber to which the feed mixture containing C 4 - to C 8 -olefins is supplied, and that a mixture containing steam is withdrawn from the mixture chamber, which mixture is heated and introduced into the reactor.