Process for reducing the naphthenic acidity of petroleum oils

Abstract

A process for reducing the naphthenic acidity of petroleum oils, or their liquid fractions, is described, the process comprising a thermal treatment of the petroleum oils, or their liquid fractions, in the presence of an adsorbent the surface of which is covered by high molecular weight carbon compounds. Preferred adsorbents are the spent or coked FCC catalysts.

What is claimed is:  
     
         1 . A process for reducing the naphthenic acidity of a feedstock of petroleum oils, or of their liquid fractions, the oil having being desalted and dewatered, wherein the process comprises the following steps: 
 a) in a reactor, contacting the naphthenic, acidic petroleum oils, or their liquid fractions, with an adsorbent, at a ratio of adsorbent/petroleum oil (or petroleum liquid fractions) in the range of from 0.1 to 5, at temperatures between 200° C. and 500° C., under pressures from of 0.01 to 0.3 MPag and residence time between 1 second and 2 hours, so as to effect the desired reduction in naphthenic acidity and obtain a treated feedstock;    b) on the treated feedstock of a), separating the used adsorbent from the petroleum oil, or from its liquid fractions so as to produce a treated, separated feedstock of reduced naphthenic acidity;    c) directing the treated, separated feedstock from b) to further processing.    
     
     
         2 . A process according to  claim 1 , wherein the ratio of adsorbent/petroleum oil (or petroleum liquid fractions)/is in the range of from 0.1 to 5.  
     
     
         3 . A process according to  claim 1 , wherein the temperature of the conversion reaction is between 250° C. and 350° C.  
     
     
         4 . A process according to  claim 1 , wherein the feedstock to be put in contact with the adsorbent is a petroleum oil, or any petroleum liquid fraction, of naphthenic acidity up to 5.0 mg KOH/g of TAN.  
     
     
         5 . A process according to  claim 1 , wherein the feedstock to be processed is a petroleum oil the salt content of which is lower than or equal to 2 Kg of salt per 160 thousand liters of petroleum.  
     
     
         6 . A process according to  claim 1 , wherein the feedstock to be processed is a petroleum oil the water content of which is lower than or equal to 0.5% by weight.  
     
     
         7 . A process according to  claim 1 , wherein the feedstock to be processed is a petroleum oil the water content of which is 0.1% by weight.  
     
     
         8 . A process according to  claim 1 , wherein the adsorbent features a high surface area and its surface is covered by high molecular weight carbon compounds.  
     
     
         9 . A process according to  claim 8 , wherein the surface area of the adsorbent is from 60 to 250 m 2 /g.  
     
     
         10 . A process according to  claim 9 , wherein the surface area of the adsorbent is from 100 to 200 m 2 /g.  
     
     
         11 . A process according to  claim 9 , wherein the adsorbent is carbon black.  
     
     
         12 . A process according to  claim 9 , wherein the adsorbent is a spent FCC catalyst.  
     
     
         13 . A process according to  claim 9 , wherein the adsorbent is a coked FCC catalyst.  
     
     
         14 . A process according to  claim 9 , wherein the adsorbent is previously treated with an alkaline solution, where the concentration of the alkaline base is in the range of from 5 to 15% by weight, in a mass ratio of alkaline base/mass of the catalyst of from 0.05 to 0.5 and, is further dried at temperatures between 100 and 120° C., for 10 to 16 hours.  
     
     
         15 . A process according to  claim 15 , wherein the base of the alkaline solution is a metal hydroxide of group IA.  
     
     
         16 . A process according to  claim 15 , wherein the alkaline base of the alkaline solution is a metal hydroxide of group IIA.  
     
     
         17 . A process according to  claim 15 , wherein the alkaline base of the alkaline solution is ammonium hydroxide.  
     
     
         18 . A process according to  claim 15 , wherein the alkaline base of the alkaline solution is a mixture of metal hydroxide of group IA, IIA and ammonium hydroxide, in any amount.  
     
     
         19 . A process according to  claim 1 , wherein the separation of the used adsorbent and the treated petroleum oil is carried out by means of a liquid/solid separation system.  
     
     
         20 . A process according to  claim 19 , wherein the liquid/solid separation system is a cyclone, a hydrocyclone or a centrifuge.