Patent ID: 7361265

Claim:
A process for the selective hydrodesulfurization of olefinic streams to reduce the sulfur content of cracked olefinic streams, while minimizing the hydrogenation degree of the olefins present in said streams, comprising: a) obtaining an admixture by combining the olefins feedstock ( 1 ) to the recycle gas ( 3 ) containing i) the hydrogen and ii) the non-reactive inert compound and to the make-up hydrogen ( 2 ), in order that the total gas (hydrogen plus inert compounds)/feedstock ratio in the admixture is comprised between 50 Nm 3 /m 3 and 5000 Nm 3 /m 3 and the H 2 /(H 2 +inert compounds) ratio in the admixture is comprised between 0.2 and 0.7; b) submitting the resulting admixture of a) to a first heat transfer in a heat transfer means ( 4 ), where said admixture is heated by the reaction product ( 9 ), yielding a heated stream ( 5 ) and then to a subsequent heater ( 6 ), in order to completely vaporize said admixture so that it may attain the reaction temperature range, of from 260° C. to 350° C.; c) processing the hot mixture resulting from b) in a hydrodesulfurization reactor ( 8 ), at a LHSV range of from 0.5 h −1 to 20 h −1 , and pressures from 0.5 Mpag to 5.0 Mpag, so as to obtain a product stream ( 10 ); d) partially condensing in condenser ( 11 ) the product stream ( 10 ), resulting in a cold stream ( 12 ) from 20° C. to 80° C. to be fed to the high pressure separator ( 13 ), where said stream ( 12 ) is separated into a desired hydrodesulfurization product ( 14 ) and a gaseous effluent ( 15 ); e) directing the hydrodesulfurization product ( 14 ) of d) to the final processing, and the gaseous effluent ( 15 ), containing mainly the inert compounds and the hydrogen plus non-condensed hydrocarbons, to a H 2 S removal step ( 16 ); f) compensating the inert compound losses by an inert compound make-up ( 18 ) to the main gaseous stream ( 17 ), in order to keep a constant concentration of the said inert compounds; and g) recompressing in compressor ( 19 ) the resulting combined stream (( 17 plus ( 18 )) to the pressure condition of the recycle gas of non-reactive compounds plus hydrogen ( 3 ).