MULTI-STEP HYDRODESULPHURISATION PROCESS

摘要

Liquid sulphur-containing hydrocarbon feedstock (1) is passed through two or more hydrodesulphurisation zones (5) and (41) connected in a series each containing a packed bed (6), (42) of solid sulphurised catalyst. The liquid is passed from the first zone to the next until the final zone. Make up hydrogen (45) is supplied to a hydrodesulphurisation zone other than the first hydrodesulphurisation zone; hydrogen-containing gas is recovered from each hydrodesulphurisation zone (11), (49). The first hydrodesulphurisation zone is supplied with hydrogen-containing gas (7) recovered from a subsequent hydrodesulphurisation zone. Hydrogen-containing gas recovered from the first hydrodesulphurisation zone is purged (17). Any other hydrodesulphurisation zone other than the first hydrodesulphurisation zone and other than the hydrodesulphurisation zone of step (i) is supplied with hydrogen-containing gas recovered from another hydrodesulphurisation zone. The sulphur content of the hydrogen-containing gas (7) and of the liquid hydrocarbon feedstock (1) suppplied to the first hydrodesulphurisation zone (5) is monitored and, if necessary, sulphur-containing material selected from H2S and active sulphur-containing materials is supplied to the first hydrodesulphurisation zone so as to maintain the catalyst charge thereof in sulphided form.