Process for hydrotreating a hydrocarbon oil

Abstract

A process or hydrotreating a hydrocarbon oil that employs a first reactor and a second reactor. The hydrocarbon oil is hydrotreated in the first reactor with a first hydrotreating catalyst in the presence of a first stream of hydrogen-containing gas to obtain a first effluent. The first effluent is separated using a stripping column to provide a hydrotreated hydrocarbon oil and used hydrogen-containing gas. A second stream of hydrogen-containing gas is heated within a section of a heating device arranged upstream of the first reactor to obtain a stream of heated hydrogen-containing gas. The stream of heated hydrogen-containing gas is contacted in the second reactor in the presence of at least part of the hydrotreated hydrocarbon oil with a second hydrotreating catalyst to obtain a second effluent which comprises a further hydrotreated hydrocarbon oil.

1 . A process for hydrotreating a hydrocarbon oil employing at least a first reactor and a second reactor, which process comprises:
 (i) providing a first stream of hydrogen-containing gas;   (ii) hydrotreating the hydrocarbon oil in the first reactor with a first hydrotreating catalyst in the presence of the first stream of hydrogen-containing gas as provided in step (i) to obtain a first effluent;   (iii) separating the first effluent as obtained in step (ii) into a hydrotreated hydrocarbon oil and used hydrogen-containing gas using a stripping column employing a hydrogen-containing gas as stripping gas;   (iv) providing a second stream of hydrogen-containing gas which is heated within a section of a heating device which is arranged upstream of the first reactor to obtain a stream of heated hydrogen-containing gas; and   (v) contacting in the second reactor at least part of the stream of heated hydrogen-containing gas as obtained in step (iv), optionally in the presence of at least part of the hydrotreated hydrocarbon oil as obtained in step (iii), with a second hydrotreating catalyst to obtain a stream of used hydrogen-containing gas, and a second effluent which comprises a further hydrotreated hydrocarbon oil when hydrotreated hydrocarbon oil as obtained in step (iii) is also present.   
     
     
         2 . A process according to  claim 1 , wherein the first stream of hydrogen-containing gas and the second stream of hydrogen-containing gas are derived from the same source of clean hydrogen-containing gas. 
     
     
         3 . A process according to  claim 1 , wherein the hydrocarbon oil to be hydrotreated is a gas oil which contains at least 75% by weight of hydrocarbons boiling in the range of from 150 to 400° C. 
     
     
         4 . A process according to  claim 1 , in which the hydrotreating conditions in steps (ii) and (v) comprise a temperature ranging from 250 to 480° C., a pressure from 10 to 150 bar, and a weight hourly space velocity of from 0.1 to 10 hr −1 . 
     
     
         5 . A process according to  claim 1 , wherein the second stream of hydrogen-containing gas contains less than 0.1% by volume of hydrogen sulphide. 
     
     
         6 . A process according to  claim 1 , wherein the first effluent as obtained in step (ii) is passed to a gas-liquid separator before using the stripping column. 
     
     
         7 . A process according to  claim 1 , wherein the used hydrogen-containing gas as obtained in step (iii) is cleaned and used again in step (v), and optionally in step (ii). 
     
     
         8 . A process according to  claim 1 , wherein step (v) is carried out in the presence of at least part of the hydrotreated hydrocarbon oil as obtained in step (iii). 
     
     
         9 . A process according to  claim 1 , wherein the hydrogen-containing gas that is being used as stripping gas in step (iii) has a temperature of from 250 to 480° C. 
     
     
         10 . A process according to  claim 1 , wherein the used hydrogen-containing gas as obtained in step (v) is used as stripping gas in step (iii). 
     
     
         11 . A process according to  claim 1 , wherein the first hydrotreating catalyst in step (ii) is a hydrodesulphurization catalyst and the second hydrotreating catalyst in step (v) is a hydrodewaxing catalyst. 
     
     
         12 . A process according to  claim 11 , wherein the hydrodesulphurization catalyst as used in step (ii) comprises one or more metals from Group VB, VIB and VIII of the Periodic Table of the Elements, on a solid carrier. 
     
     
         13 . A process according to  claim 11 , wherein the hydrodewaxing catalyst as used in step (v) comprises as catalytically active metal one or more noble metals from Group VIII of the Periodic Table of the Elements on a solid carrier.