Production of paraffin fuels using renewable materials by a continuous hydrotreatment comprising a pre-treatment step under hydrogen

摘要

A process for hydrotreatment of a feed from renewable sources such as vegetable oils for the production of paraffinic hydrocarbons comprising a pre-treatment step by crystallization and/or precipitation and pre-hydrogenation of the feed under hydrogen allowing the elimination of insoluble inorganic impurities under hydrotreatment conditions and improved exothermal management of the reaction. The effluent is separated to a gas fraction and a liquid fraction containing paraffinic hydrocarbons, a portion of said liquid fraction is recycled.

主权项

1. A process for the hydrotreatment of a feed originating from renewable sources in order to produce paraffinic hydrocarbons, comprising at least:
a) mixing a total feed flow F0 with a recycle flow RPP comprising at least a portion of a liquid fraction R containing paraffinic hydrocarbons from separation d) and with a flow of a hydrogen-rich gas H2P, to produce a mixture M, bringing mixture M to a temperature of between 140 and 250° C.; b) preheating said mixture M in a pre-treatment zone in which flow of said mixture M takes place via a porous medium consisting of a particle bed referred to as a fixed bed, said particle bed comprising solid catalytic materials that are optionally mixed with solid non-catalytic materials and said fixed bed having a void fraction of between 0.25 and 0.8; c) hydrotreating at least one effluent resulting from pre-treatment in b) (F+εRPP+δH2PP), ε and δ being between 0 and 1, in the presence of hydrogen in excess of theoretical hydrogen consumption and under hydrotreatment conditions in a fixed bed reactor having a plurality of catalytic zones disposed in series and comprising a hydrotreatment catalyst, dividing said effluent into at least a certain number of different part flows (F1+ε1RPP+δ1H2PP) to (Fn+εnRPP+δnH2PP) equal to the number of catalytic zones n in the reactor, injecting a first part flow (F1+ε1RPP+δ1H2PP) into a first catalytic zone, a second part flow (F2+ε2RPP+δ2H2PP) is injected into a second catalytic zone and so on, if n greater than 2; injecting various part flows into successive catalytic zones in increasing proportions such that F1/F is less than or equal to F2/F, which itself is less than or equal to F3/F and so on until F(n−1)/F is less than or equal to Fn/F, in order to produce an effluent containing paraffinic hydrocarbons; d) separating said effluent containing paraffinic hydrocarbons in at least one separation allowing separation of at least one gaseous fraction and at least one liquid fraction containing the paraffinic hydrocarbons; e) dividing at least a portion R of said liquid fraction containing the paraffinic hydrocarbons from b) into at least a flow RLC and into said recycle flow RPP upstream of a) and mixed with the total feed flow F0 and said flow RLC is divided into at least a certain number of different part flows R1-Rn less than or equal to the number of catalytic zones n in the reactor, said flows R1-Rn being recycled upstream of the catalytic zones 1-n, so that the weight ratio between the flow of paraffinic hydrocarbons (R1+δ1RPP) sent to the first catalytic zone and the part flow F1 of the feed introduced into the first catalytic zone is greater than or equal to 10.