Process for desulfurization of diesel with reduced hydrogen consumption

Abstract

The present invention relates to a novel process for desulfurization of diesel with reduced hydrogen consumption. More particularly the subject invention pertains to an integrated process comprising diesel hydro de-sulfurisation (DHDS) or diesel hydrotreatment (DHDT) with reduced severity to desulfurize high sulfur (1.0-2.0 wt %) diesel stream to a much lower level of sulfur content of 350-500 ppm in the depleted diesel stream, followed by a novel adsorption procedure for effecting deep desulfurization to reduce overall sulfur content to less than 10 ppm with reduced hydrogen consumption, as compared to high severity DHDS or DHDT procedures of the prior art.

1 . A process for desulfurization of diesel with reduced hydrogen consumption comprising the steps of:
 hydrotreating high sulfur-containing diesel stream (1.0-2.0% by wt. of 5) over a NiMo catalyst to reduce sulfur-content to a level of 350-500 ppm and   subjecting the treated diesel stream to an adsorption procedure to bring down sulfur content to less than 10 ppm.   
     
     
         2 . The process as claimed in  claim 1 , wherein treated diesel containing about 350 ppm of refractory sulfur is split into two cuts, such as
 (i) with IBP-140-150° C.-280/300° C. containing less than 10 ppm sulfur, and   (ii) with FBP-280/300° C. containing about 500-600 ppm of refractory sulfur,   wherein the cut containing less than 10 ppm sulfur may be blended into diesel stream without any further treatment.   
     
     
         3 . The process as claimed in  claim 2 , wherein the cut with FBP 280/300° C. containing about 500-600 ppm of refractory sulfur is desulfurized by the adsorption procedure. 
     
     
         4 . The process as claimed in  claim 1 , wherein the process reduces hydrogen consumption by 20% to 40%. 
     
     
         5 . A process for desulfurization of diesel with reduced hydrogen consumption comprising the steps of:
 hydrodesulphurizing high sulfur-containing diesel stream (1.0-2.0% by wt. of 5) over a CoMo catalyst to reduce sulfur-content to a level of 350-500 ppm and   subjecting the desulphurized diesel stream to an adsorption procedure to bring down sulfur content to less than 10 ppm.   
     
     
         6 . The process as claimed in  claim 5 , wherein desulphurized diesel containing about 350 ppm of refractory sulfur is split into two cuts, such as
 (i) with IBP-140-150° C.-280/300° C. containing less than 10 ppm sulfur, and   (ii) with FBP-280/300° C. containing about 500-600 ppm of refractory sulfur,   wherein the cut containing less than 10 ppm sulfur may be blended into diesel stream without any further treatment.   
     
     
         7 . The process as claimed in  claim 6 , wherein the cut with FBP 280/300° C. containing about 500-600 ppm of refractory sulfur is desulfurized by the adsorption procedure. 
     
     
         8 . The process as claimed in  claim 5 , wherein the process reduces hydrogen consumption by 20% to 40%. 
     
     
         9 . The adsorption process as claimed in  claim 1 , further comprising the following steps:
 operating two fixed bed reactors in swing mode of adsorption and regeneration, and   contacting the cut having FBP 280/300° C. with the adsorbent along with hydrogen in down or up-flow mode at a temperature of 350-400° C., pressure of 15-30 bar, hydrogen to hydrocarbon ratio of 100-400 Nm 3 /m 3 , and liquid hourly space velocity of 0.5-2.0 h −1 , depending on the sulfur content of the cut.   
     
     
         10 . The process as claimed in  claim 9 , wherein the sulfur compounds are chemically adsorbed on the adsorbent followed by cleavage of sulfur from the sulfur compound and hydrocarbon molecules of the sulfur compound are released back into the hydrocarbon stream. 
     
     
         11 . The process as claimed in  claim 9 , wherein the adsorbent is regenerated by controlled oxidation of the adsorbed carbon and sulfur with lean air at a temperature ranging between 350° and 500° C. and activation with hydrogen, wherein the process is carried out in situ. 
     
     
         12 . (canceled) 
     
     
         13 . The process as claimed in  claim 2 , wherein the process reduces hydrogen consumption by 20% to 40%. 
     
     
         14 . The process as claimed in  claim 3 , wherein the process reduces hydrogen consumption by 20% to 40%. 
     
     
         15 . (canceled) 
     
     
         16 . (canceled) 
     
     
         17 . The process as claimed in  claim 6 , wherein the process reduces hydrogen consumption by 20% to 40%. 
     
     
         18 . The process as claimed in  claim 7 , wherein the process reduces hydrogen consumption by 20% to 40%. 
     
     
         19 . (canceled) 
     
     
         20 . The adsorption process as claimed in  claim 5 , further comprising the following steps:
 operating two fixed bed reactors in swing mode of adsorption and regeneration, and   contacting the cut having FBP 280/300° C. with the adsorbent along with hydrogen in down or up-flow mode at a temperature of 350-400° C., pressure of 15-30 bar, hydrogen to hydrocarbon ratio of 100-400 Nm 3 /m 3 , and liquid hourly space velocity of 0.5-2.0 h −1 , depending on the sulfur content of the cut.   
     
     
         21 . The process as claimed in  claim 20 , wherein the sulfur compounds are chemically adsorbed on the adsorbent followed by cleavage of sulfur from the sulfur compound and hydrocarbon molecules of the sulfur compound are released back into the hydrocarbon stream. 
     
     
         22 . The process as claimed in  claim 20 , wherein the adsorbent is regenerated by controlled oxidation of the adsorbed carbon and sulfur with lean air at a temperature ranging between 350° and 500° C. and activation with hydrogen, wherein the process is carried out in situ. 
     
     
         23 . The process as claimed in  claim 10 , wherein the adsorbent is regenerated by controlled oxidation of the adsorbed carbon and sulfur with lean air at a temperature ranging between 350° and 500° C. and activation with hydrogen, wherein the process is carried out in situ. 
     
     
         24 . The process as claimed in  claim 21 , wherein the adsorbent is regenerated by controlled oxidation of the adsorbed carbon and sulfur with lean air at a temperature ranging between 350° and 500° C. and activation with hydrogen, wherein the process is carried out in situ.