Process for the selective hydrodesulfurization of oleofinic naphtha streams

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, wherein said process comprises the following steps:

• 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 is comprised between 50 Nm3/m3 and 5000 Nm3/m3 and the H2/(H2+inert compounds) ratio 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 H2S 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;
• 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).