Processo para gerar olefinas a partir do etanol

摘要

The present invention relates to a process for the conversion of ethanol to make essentially ethylene and propylene, comprising: a) introducing in a reactor (A) (also called the first low temperature reaction zone) a stream comprising ethanol under a partial pressure at least about 0.2 MPa, optionally water, optionally an inert component, b) contacting said stream with a catalyst (A1) in said reactor (A) at conditions effective to convert at least a portion of the ethanol to essentially ethylene, propylene and olefins having 4 carbon atoms or more (C4+ olefins), c) recovering from said reactor an effluent comprising : ethylene and C4+ fraction containing mainly olefins having 4 carbon atoms or more (C4+ olefins), propylene and various hydrocarbons, water, optionally unconverted ethanol and the optional inert component of step a), d) fractionating said effluent of step c) to remove water, unconverted ethanol, optionally the inert component, optionally the propylene and optionally the whole or a part of the various hydrocarbons to get a stream (D) comprising essentially ethylene, olefins having 4 carbon atoms or more (C4+ olefins) and optionally the inert component, e) introducing at least a part of said stream (D) optionally mixed with a stream (D1) comprising olefins having 4 carbon atoms or more (C4+ olefins) in a OCP reactor (also called the second high temperature reaction zone) under the condition that said mixture (D)+(D1) comprises at least 10 wt % of C4+ olefins, f) contacting said stream comprising at least a part of (D) and the optional (D1) in said OCP reactor with a catalyst which is selective towards light olefins in the effluent, to produce an effluent with an olefin content of lower molecular weight than that of the feedstock, g) fractionating said effluent of step f) to produce at least an ethylene stream, a propylene stream and a fraction consisting essentially of hydrocarbons having 4 carbon atoms or more, optionally recycling ethylene in whole or in part at the inlet of the OCP reactor of step f), or at the inlet of the reactor (A) or in part at the inlet of the OCP reactor of step f) and in part at the inlet of the reactor (A), optionally recycling the fraction consisting essentially of hydrocarbons having 4 carbon atoms or more at the inlet of the OCP reactor.