Process for desulphurization of petroleum oil

Abstract

A process for desulphurization of petroleum oil, comprising the step of diluting the feed oil with a suitable organic solvent prior to the desulphurization reaction, is disclosed. The organic solvent is selected from alkanes, alkenes, cyclic alkenes and alkynes, and particularly selected from n-hexane, cyclohexane, heptane, pentene, hexene, heptene, octene, toluene and xylene. The solvent concentration in the mixture of feed oil and solvent is in the range of 0.1-70%.

1 . A process for desulphurization of petroleum oils, said process comprising the following steps:
 diluting petroleum oil with a hydrocarbon organic solvent selected from the group consisting of alkanes, alkenes, cyclic alkenes and alkynes, to obtain an oil-solvent mixture, wherein the organic solvent concentration in the oil-solvent mixture is in the range of 0.1-70%;   transferring the oil-solvent mixture to a reactor vessel;   adding solid sodium metal to the oil-solvent mixture in the reactor vessel, wherein the sodium concentration is between 0.1-20% of the petroleum oil concentration;   reacting the oil-solvent mixture with sodium at a temperature in the range of 240-350° C. and a pressure in the range of 0-500 psig for 15 minutes-4 hours under mixing to obtain a resultant mixture;   cooling and settling the resultant mixture; and   decanting the cooled mixture and filtering the decanted solution of desulfurized petroleum oil.   
     
     
         2 . The process as claimed in  claim 1 , wherein the hydrocarbon organic solvent is selected from the group consisting of n-hexane, cyclohexane, heptane, pentene, hexene, heptene, octene, toluene and xylene. 
     
     
         3 . The process as claimed in  claim 1 , which includes the step of purging the reactor vessel with hydrogen gas at a pressure in the range of 0-500 psig. 
     
     
         4 . The process as claimed in  claim 1 , which includes the step of separating the organic solvent from desulfurized petroleum oil by distillation. 
     
     
         5 . The process as claimed in  claim 1 , which includes the step of mixing sodium with the oil-solvent mixture in the reactor vessel by using high shear mixing by means of a mixer selected from an inline mixer, a mechanical mixer, a pump around loop and an ultrasonic mixer. 
     
     
         6 . The process as claimed in  claim 1 , which includes the step of removing residual sodium metal by: treating the desulfurized petroleum oil with 0.1-10% carboxylic acid in an organic solvent at a temperature in the range of 50-150° C. for 30 minutes to 90 minutes under vigorous stirring; and filtering the resultant mixture to obtain desulfurized petroleum oil having sodium content between 10-50 ppm. 
     
     
         7 . The process as claimed in  claim 6 , wherein the carboxylic acid is selected from acetic acid, formic acid and propionic acid. 
     
     
         8 . The process as claimed in  claim 6 , wherein the organic solvent is selected from alkanes, alkenes, cyclic alkenes, alkynes and alcohol. 
     
     
         9 . The process as claimed in  claim 6 , wherein the organic solvent is xylene. 
     
     
         10 . The process as claimed in  claim 1 , which includes the step of removing residual sodium metal by purging the desulfurized petroleum oil with air at a temperature in the range of 30-150° C.