FIELD: chemistry.
SUBSTANCE: inventions relate to methods for the production of propylene. A method for the production of propylene from ethylene and butene is described, including: isomerization of a hydrocarbon flow under liquid-phase conditions in an isomerization reactor, supply of an isomerized hydrocarbon flow into a metathesis reactor, and bringing the isomerized hydrocarbon flow into contact with a metathesis catalyst to obtain a product flow, while the isomerization reactor converts part of butene-1 into butene-2, and it is located before the metathesis reactor or in a recirculation flow(s) concentrated relatively to butene, wherein the hydrocarbon flow contains n-butenes and paraffins, in which the maximum butadiene content is approximately 0.5 wt.%, and the maximum isobutylene content is approximately 10 wt.%. A method for the production of propylene from ethylene and butene is described, including: i) combination of a hydrocarbon flow containing n-butenes and paraffins, in which the maximum butadiene content is approximately 0.5 wt.%, and the maximum isobutylene content is approximately 10 wt.%, with an ethylene flow; ii) bringing combined hydrocarbon flow and ethylene flow from the stage (i) into contact with a metathesis catalyst in the metathesis reactor to obtain a product flow containing ethylene, propylene, C4 olefins containing butene-2 and butene-1, heavier olefins, and paraffins; iii) separation of ethylene from the product flow to obtain an ethylene recirculation flow and a cubic residue flow containing propylene, paraffins, C4 olefins containing butene-2 and butene-1, and C5+ hydrocarbons; iv) fractionation of the cubic residue flow to obtain at least a propylene fraction, a fraction of the recirculation flow concentrated relatively to butene, containing paraffins, olefins, butene-2, butene-1, C5 hydrocarbons, and a C4+ hydrocarbon fraction; (v) return of the ethylene recirculation flow from the stage (iii) and the recirculation flow concentrated relatively to butene from the stage (iv) to the stage (i), and (vi) isomerization under liquid-phase conditions in the isomerization reactor in a liquid phase of at least one flow selected from a group consisting of the recirculation flow concentrated relatively to butene before the stage (i), the hydrocarbon flow before the stage (i), the combined flow containing the recirculation flow concentrated relatively to butene, and the hydrocarbon flow before the stage (i), and the product flow before the stage (iii) to obtain the specified propylene.
EFFECT: increase in the yield of propylene.
17 cl, 5 dwg, 3 tbl
