Catalytical hydrodesulfurization of kerosene in two steps on cobalt-molybdenum catalyst and intermediate stripping

Abstract

A process for selective removal of mercaptan from aviation turbine fuel feed includes mixing aviation turbine fuel feed with hydrogen, at a pressure in a range from 3 bar to 20 bar to obtain a reaction mixture. The reaction mixture is heated at a temperature range of 150° C. to 350° C. to obtain a heated mixture. The heated mixture is reacted with a hydrotreating catalyst in a rector to obtain a reactor effluent, and H 2 S gas is stripped from the reactor effluent to obtain a stripper bottom product. Moisture is removed from the stripper bottom product to obtain aviation turbine fuel product having less than 10 ppm mercaptan. The aviation fuel product has improved properties such as color and acidity. Embodiments also relate to an aviation turbine fuel product having less than 10 ppm mercaptan prepared by the described process of the present invention.

1 . A process for selective removal of mercaptan from aviation turbine fuel (ATF) feed comprising:
 mixing aviation turbine fuel feed with hydrogen, at a pressure in range of 3 bar to 20 bar to obtain a reaction mixture,   heating the reaction mixture at a temperature range of 150° C. to 350° C. to obtain a heated mixture,   reacting the heated mixture with a hydrotreating catalyst in a rector to obtain a reactor effluent,   stripping H 2 S gas from the reactor effluent to obtain a stripper bottom product, and   removing moisture from the stripper bottom product to obtain aviation turbine fuel product having less than 10 ppm mercaptan.   
     
     
         2 . The process as claimed in  claim 1 , wherein the hydrogen is in gaseous state and a ratio between the hydrogen gas and aviation turbine fuel feed is in the range of 20:1 to 50:1. 
     
     
         3 . (canceled) 
     
     
         4 . The process as claimed in  claim 1 ,
 wherein the aviation turbine fuel feed has boiling range of about 120° C. to about 300° C., preferably between about 140° C. to about 280° C.   
     
     
         5 . The process as claimed in  claim 2 , wherein the hydrogen gas is reformer off-gas or recycle gas from diesel hydrotreating (DHDT) unit or diesel hydrodesulfurisation (DHDS) unit. 
     
     
         6 . The process as claimed in  claim 1 , wherein said process is performed at a Liquid Hourly Space Velocity in the range of 4.0 hr ″1  to 6.0 hr ″1 . 
     
     
         7 . The process as claimed in  claim 1 , wherein the hydrotreating catalyst is cobalt molybdenum catalyst or nickel molybdenum catalyst. 
     
     
         8 . The process as claimed in  claim 7 , wherein the catalyst is supported on alumina. 
     
     
         9 . The process as claimed in  claim 7 , wherein the catalyst is sulfided prior to use. 
     
     
         10 . The process as claimed in  claim 1 , wherein the pressure is in the range of about 5 bar to 15 bar, preferably 8 bar to 12 bar. 
     
     
         11 . The process as claimed in  claim 1 , wherein the temperature is in the range of 225° C.-350° C. 
     
     
         12 . An aviation turbine fuel product having less than 10 ppm mercaptan prepared by a process as claimed in  claim 1 . 
     
     
         13 . The process for selective removal of mercaptan from aviation turbine fuel (ATF) feed, comprising:
 (a) mixing aviation turbine fuel feed with a source of hydrogen, at the hydrogen to aviation turbine fuel feed ratio in the range of 0.0003:1 to 0.0007:1, and at a pressure in range of 3 bar to 20 bar to obtain a first reaction mixture,   (b) heating the first reaction mixture at a temperature range of 150° C. to 350° C. to obtain a heated mixture,   (c) reacting the heated mixture with a hydrotreating catalyst in a rector to obtain a reactor effluent,   (d) stripping H 2 S gas from the reactor effluent in an stripper to obtain a stripper bottom product,   (e) mixing the stripper bottom product with the heated mixture obtained in step (b), at the stripper bottom product to heated mixture ratio in the range of 1:1 to 10:1 to obtain a second reaction mixture,   (f) reacting the second reaction mixture with a hydrotreating catalyst in a rector to obtain a reactor effluent,   (g) stripping H 2 S gas from the reactor effluent in an stripper to obtain a stripper bottom product,   (h) repeating steps (e) to (g), and   (i) removing moisture from the stripper bottom product to obtain aviation turbine fuel product having less than 10 ppm mercaptan.   
     
     
         14 . The process as claimed in  claim 13 , wherein the aviation turbine fuel feed has boiling range of about 120° C. to about 300° C., preferably between about 140° C. to about 280° C. 
     
     
         15 . The process as claimed in  claim 13 , wherein the source of hydrogen is reformer off-gas or recycle gas from diesel hydrotreating (DHDT) unit or diesel hydrodesulfurisation (DHDS) unit. 
     
     
         16 . The process as claimed in  claim 13 , wherein said process is performed at a Liquid Hourly Space Velocity in the range of 4.0 hr ″1  to 6.0 hr ″1 . 
     
     
         17 . The process as claimed in  claim 13 , wherein the hydrotreating catalyst is cobalt molybdenum catalyst or nickel molybdenum catalyst. 
     
     
         18 . The process as claimed in  claim 17 , wherein the catalyst is supported on alumina. 
     
     
         19 . The process as claimed in  claim 17 , wherein the catalyst is sulfided prior to use. 
     
     
         20 . The process as claimed in  claim 13 , wherein the pressure is in the range of about 5 bar to 15 bar, preferably 8 bar to 12 bar. 
     
     
         21 . The process as claimed in  claim 13 , wherein the temperature is in the range of 225° C.-350° C. 
     
     
         22 . An aviation turbine fuel product having less than 10 ppm mercaptan prepared by a process as claimed in  claim 13 .