Process for removing metal ions from crude oil

Abstract

A process for removing metal ions from crude oil comprising contacting a non-ionic amphiphilic solvent with the crude oil, optionally, in the presence of water, so as to produce a metal ion-containing phase, and separating the metal ion-containing phase from the crude oil.

1 . A process for removing metal ions from crude oil comprising 
 a) contacting a non-ionic amphiphilic solvent with the crude oil, optionally, in the presence of water, so as to produce a metal ion-containing phase, and    b) separating the metal ion-containing phase from the crude oil.    
     
     
         2 . A process as claimed in  claim 1 , wherein step a) is carried out in the presence of water.  
     
     
         3 . A process as claimed in  claim 1  or  2 , wherein the non-ionic amphiphilic solvent comprises an alcohol or an alcohol derivative.  
     
     
         4 . A process as claimed in  claim 3 , wherein said solvent comprises a polyol.  
     
     
         5 . A process as claimed in  claim 3 , wherein said solvent comprises an alkyltriglycol ether.  
     
     
         6 . A process as claimed in  claim 3 , wherein said solvent comprises at least one compound selected from the group consisting of n-butyltriglycol ether, ethylene glycol mono ethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-iso-butyl ether, ethylene glycol mono-2-butyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol mono-iso-propyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-iso-butyl ether, diethylene glycol mono-2-butyl ether, diethylene glycol mono-tert-butyl ether, diethylene glycol mono-n-pentyl ether, diethylene glycol mono-2-methylbutyl ether, diethylene glycol mono-3-methyl butyl ether, diethylene glycol mono-2- pentyl ether, diethylene glycol mono-3-pentyl ether, diethylene glycol mono-tert-pentyl ether, tetraethylene glycol mono butyl ether, and pentaethylene glycol mono butyl ether.  
     
     
         7 . A process as claimed in  claim 6 , wherein said solvent is a mixture of n-butyltriglycol ether, n-butyldiglycol ether, n-butyl tetraglycol ether and n-butyl pentaglycol ether.  
     
     
         8 . A process as claimed in  claim 7 , wherein said mixture comprises 75 w/w % n-butyltriglycol ether, 2.5 w/w % n-butyldiglycol ether, 19.0 w/w % n-butyl tetraglycol ether and 2.0 w/w % n-butylpentaglycol ether.  
     
     
         9 . A process as claimed,,n any preceding claim, wherein the metal ion-containing phase is separated from the crude oil using a density separator.  
     
     
         10 . A process as claimed in any preceding claim, wherein prior to separating the metal ion-containing phase from the crude oil, the reaction mixture of step a) is heated to at least 70° C.  
     
     
         11 . A process as claimed in any preceding claim, which further comprises the step of recovering at least some of the non-ionic amphiphilic solvent from the metal-containing phase separated in step b) for re-use.  
     
     
         12 . A process as claimed in  claim 11 , wherein the non-ionic amphiphilic solvent is recovered from the metal-containing phase by distillation, a membrane, an ion-exchange column and/or an additional solvent extraction step.  
     
     
         13 . A process as claimed in any preceding claim, wherein step a) is carried out at between ambient temperature and 160° C.  
     
     
         14 . A process as claimed in any one of  claims 2  to  13 , wherein the non-ionic amphiphilic solvent is contacted with the crude oil as an 8 to 70 w/w % aqueous solution of the solvent.  
     
     
         15 . A process as claimed in any preceding claim, wherein the amount of non-ionic amphiphilic solvent employed forms 5 to 40 wt % of the total amount of oil, amphiphilic solvent and optional water in the reaction mixture of step a).  
     
     
         16 . A process for reducing the acidity of crude oil, comprising contacting crude oil with 
 i) a metal-containing neutralising agent in the presence of water, and    ii) a non-ionic amphiphilic solvent, so as to produce a metal-containing phase, and optionally, separating the metal-containing phase from the crude oil.    
     
     
         17 . A process as claimed in  claim 16 , wherein the metal containing neutralising agent is a hydroxide, oxide and/or carbonate of a Group IA and/or Group IIA metal.  
     
     
         18 . A process as claimed in  claim 17 , wherein the metal containing neutralising agent is calcium hydroxide.  
     
     
         19 . A process as claimed in any one of  claims 16  to  18 , wherein the non-ionic amphiphilic solvent employed is contacted with the crude oil before, after or at the same time as the metal-containing neutralising agent.  
     
     
         20 . A process as claimed in  claim 19 , wherein the non-ionic amphiphilic solvent is contacted with the oil after the metal-containing neutralising agent is contacted with the crude oil.  
     
     
         21 . A process as claimed in any one of  claims 16  to  20 , wherein a demulsifier is added to the reaction mixture of step i), prior to the addition of the non-amphiphilic solvent of step ii).