Process for capturing mercury and arsenic comprising evaporation then condensation of a hydrocarbon-containing cut

Abstract

A process for capturing mercury and possibly arsenic comprising at least: a) vaporising (or flashing, step a1) then condensing a hydrocarbon-containing feed (step a2) without separating said feed; b) treating the effluent from step a2 comprising at least one step for bringing said effluent into contact with hydrogen and a catalyst, and optionally capturing arsenic; c) a step consisting in passing the effluent from step b) over a mercury capture mass.

1 . A process for capturing mercury and possibly arsenic comprising at least: 
 a) vaporising (or flashing, step a1) then condensing a hydrocarbon-containing feed (step a2) without separating said feed;    b) treating the effluent from step a 2), comprising at least one step for bringing said effluent into contact with hydrogen and a catalyst;    c) a step consisting of passing the effluent from step b) over a mercury capture mass.    
     
     
         2 . A process according to    claim 1   , in which step a1) is operated at a temperature in the range from the temperature of the end point of the feed reduced by 20° C. to the temperature of the end point of the feed increased by 20° C., and at a pressure in the range 0.1 to 5 MPa.  
     
     
         3 . A process according to    claim 1    or    claim 2   , in which step a2) is operated at a temperature that is lower than that of step a1) and in the range -10° C. to 500° C., and at a pressure in the range 0.1 to 5 MPa.  
     
     
         4 . A process according to any one of claims  1  to 3, in which step b) is operated at a temperature in the range 130° C. to 250° C., a pressure in the range 0.1 to 5 MPa and at a hydrogen flow rate in the range 1 to 500 h −1 .  
     
     
         5 . A process according to any one of    claims 1    to    4   , in which step c) is operated at a temperature in the range 0° C. to 175° C., a pressure in the range 0.1 to 5 MPa, and at a space velocity in the range 1 to 50 h −1 .  
     
     
         6 . A process according to    claims 1    to    5   , in which the catalyst is based on sulphided nickel and is also capable of capturing arsenic.  
     
     
         7 . A process according to any one of    claims 1    to    6   , in which the catalyst comprises at least one metal selected from the group formed by nickel, cobalt, iron and palladium, and in which at least 50% of said metal is in the reduced state.  
     
     
         8 . A process according to any one of    claims 1    to    7   , in which the catalyst also comprises a support selected from the group formed by: alumina, silica, silica-aluminas, zeolites, activated charcoal, clays and aluminous cements.  
     
     
         9 . A process according to any one of    claims 1    to    8   , in which the capture mass contains sulphur and a metal at least partially in the form of a sulphide.  
     
     
         10 . A process according to    claim 9   , in which the metal is selected from the group formed by copper, iron and silver.  
     
     
         11 . A process according to    claim 9    or    claim 10   , in which the quantity of metal combined or otherwise in the form of the sulphide is in the range 0.1% by weight to 20% by weight with respect to the total weight of the capture mass, and the quantity of elemental sulphur, combined or otherwise, of said mass is in the range 1% by weight to 40% by weight.  
     
     
         12 . A process according to any one of    claims 9    to    11   , in which the capture mass also comprises a support selected from the group formed by: silica, alumina, silica-aluminas, zeolites, clays, activated charcoal and aluminous cements.