Method for treating a petrol containing sulphur compounds

A process for treating a gasoline containing sulfur compounds, olefins and diolefins, the process comprising:

• a) bringing the gasoline, hydrogen and a hydrodesulfurization catalyst comprising an oxide support and an active phase comprising a group VIB metal and a group VIII metal into contact in at least one reactor at a temperature of between 21° and 320° C., at a pressure of between 1.5 and 3 MPa, with a space velocity of between 1 and 10 h−1 and a ratio of the hydrogen flow rate, expressed in normal m3 per hour, to the flow rate of feedstock to be treated, expressed in m3 per hour at standard conditions, of between 100 and 600 Nm3/m3, so as to convert at least a portion of the sulfur compounds into H2S;
• b) bringing the effluent resulting from a) without removal of the H2S formed, hydrogen and a hydrodesulfurization catalyst comprising an oxide support and an active phase consisting of at least one group VIII metal are brought into contact in at least one reactor at a temperature of between 280 and 400° C., at a pressure of between 1.0 and 3 MPa, with a space velocity of between 1 and 10 h−1 and a ratio of the hydrogen flow rate, expressed in normal m3 per hour, to the flow rate of feedstock to be treated, expressed in m3 per hour at standard conditions, of between 100 and 600 Nm3/m3;
• c) the effluent resulting from b) is sent to at least one separation drum operating at a pressure of between 1.0 and 2.0 MPa to obtain a gaseous fraction containing H2S and hydrogen and a liquid fraction containing desulfurized gasoline and a fraction of residual H2S;
• d) said liquid fraction obtained in c) is sent to a stabilization column to obtain at the top a stream comprising residual H2S and C4- hydrocarbon compounds and at the bottom a stabilized gasoline;
• e) the gaseous fraction obtained on completion of c) is recycled at least in part to at least one of a) and/or b).