On-board desulfurization system

Abstract

A fuel desulfurization system that can be located on-board a transportation vehicle. The desulfurization system contains a unique sorption vessel having a vacuum shell design to ensure a prescribed axial and radial temperature profile under operating conditions.

1 . An on-board desulfurization system for removing sulfur moieties from transportation fuels, which system comprises:
 a) a heat exchanger having a first passageway and a second passageway contiguous to each other but not in fluid communication with each other, wherein each of said passageways having an inlet and an outlet and wherein each passageway is constructed to allow a fluid to pass from its inlet to its outlet and to allow heat to be transferred from a fluid of one passageway to a fluid in the other passageway;   b) a first fuel pump having an inlet and an outlet wherein the outlet of said first fuel pump is in fluid communication with the inlet of said first passageway of said heat exchanger;   c) a sulfur trap vessel having and inlet and an outlet and containing a bed of sorbent material having the capacity to sorb sulfur compounds from a transportation fuel stream and wherein said inlet of said sulfur trap vessel is in fluid communication with the outlet of said first passageway of said heat exchanger and said outlet of said sulfur trap vessel is in fluid communication with the inlet of said second passageway of said heat exchanger;   d) an enclosed tank having an inlet and an outlet wherein said inlet is in fluid communication with the outlet of said second passageway of said heat exchanger; and   e) a second fuel pump having an inlet and an outlet wherein said inlet is in fluid communication with the outlet of said enclosed tank.   
     
     
         2 . The on-board desulfurization system of  claim 1  wherein said sorbent material is a composite comprised of: i) a high surface area support comprising silica, alumina, carbon or a combination thereof, and ii) nickel phosphide particles disposed on the support, said particles comprising one or more selected from the group consisting of Ni 2 P, Ni 12 P 5 , and Ni 3 P. 
     
     
         3 . The on-board desulfurization system of  claim 2  wherein said particles range in size from about 2 nm to about 30 nm. 
     
     
         4 . The on-board desulfurization system of  claim 3  wherein said particles comprise from about 15 wt. % to about 80 wt. % of the sorbent material. 
     
     
         5 . The on-board desulfurization system of  claim 4  wherein said support comprises silica, mesoporous silica, silica-alumina, carbon and mixtures thereof. 
     
     
         6 . The on-board desulfurization system of  claim 5  wherein said support is further characterized as having a surface area ranging from about 200 m 2 /g to about 800 m 2 /g. 
     
     
         7 . The on-board desulfurization system of  claim 1  wherein the heat exchanger is selected from a tube and shell type, a plate type, and a plate and fin type. 
     
     
         8 . The on-board desulfurization system of  claim 7  wherein the heat exchanger is a tube and shell type heat exchanger. 
     
     
         9 . The on-board desulfurization system of  claim 1  wherein the inlet of said first fuel pump is in fluid communication with a source of fuel, which fuel is a transportation fuel. 
     
     
         10 . The on-board desulfurization system of  claim 1  wherein the sulfur trap vessel is insulated. 
     
     
         11 . The on-board desulfurization system of  claim 10  wherein the sulfur trap vessel is insulated by use of a surrounding containment vessel that is sealed to the outside environment and is positioned with respect to the sulfur trap vessel so as to provide a gap between the two vessels. 
     
     
         12 . The on-board desulfurization system of  claim 11  wherein there is a vacuum in the gap between the two vessels. 
     
     
         13 . The on-board desulfurization system of  claim 12  wherein the outlet of said second fuel pump is in fluid communication with a reforming unit capable of producing hydrogen from the transportation fuel. 
     
     
         14 . The on-board desulfurization system of  claim 1  wherein the sulfur trap vessel is cylindrical in shape. 
     
     
         15 . The on-board desulfurization system of  claim 14  wherein there is provided a baffle system within the sulfur trap vessel. 
     
     
         16 . The on-board desulfurization system of  claim 15  wherein the baffle system runs substantially the entire internal length of the sulfur trap vessel. 
     
     
         17 . The on-board desulfurization system of  claim 1  wherein the sulfur trap vessel is composed of a materials selected from the group consisting of a stainless steel, composites comprised of a polymer composited with a material selected from the group consisting of carbon particles, carbon fibers, carbon nanofibers, ceramic particles, and ceramic fibers. 
     
     
         18 . The on-board desulfurization system of  claim 1  wherein there is provided a heating means within the sulfur trap vessel capable of heating the sorbent bed to a predetermined temperature. 
     
     
         19 . The on-board desulfurization system of  claim 18  wherein the heating means is an electrically powered heating element. 
     
     
         20 . An on-board desulfurization system for removing sulfur moieties from transportation fuels, which system comprises:
 a) a tube and shell heat exchanger comprised of a plurality of tubes, each having an inlet and an outlet and a shell surrounding said tubes and having an inlet and an outlet;   b) a first fuel pump having an inlet and an outlet wherein the outlet of said first fuel pump is in fluid communication with the inlet of at least one tube of said heat exchanger;   c) a sulfur trap vessel having and inlet and an outlet and containing a bed of sorbent material having the capacity to sorb sulfur compounds from a transportation fuel stream and wherein said inlet of said sulfur trap vessel is in fluid communication with the outlet of said at least one tube of said heat exchanger and said outlet of said sulfur trap vessel is in fluid communication with the inlet of said shell of said heat exchanger, wherein the sorbent material is a composite comprised of: i) a high surface area support comprising silica, alumina, carbon or a combination thereof, and ii) nickel phosphide particles disposed on the support, said particles comprising one or more selected from the group consisting of Ni 2 P, Ni 12 P 5 , and Ni 3 P;   d) an enclosed tank having an inlet and an outlet wherein said inlet is in fluid communication with the outlet of said shell of said heat exchanger; and   e) a second fuel pump having an inlet and an outlet wherein said inlet is in fluid communication with the outlet of said enclosed tank.   
     
     
         21 . The on-board desulfurization system of  claim 20  wherein said particles range in size from about 2 nm to about 30 nm and comprise from about 15 wt. % to about 80 wt. % of the sorbent material. 
     
     
         22 . The on-board desulfurization system of  claim 21  wherein said support comprises silica, mesoporous silica, silica-alumina, carbon and mixtures thereof and wherein said support is further characterized as having a surface area ranging from about 200 m 2 /g to about 800 m 2 /g. 
     
     
         23 . The on-board desulfurization system of  claim 20  wherein the sulfur trap vessel is insulated by use of a surrounding containment vessel that is sealed to the outside environment and is positioned with respect to the sulfur trap vessel so as to provide a gap between the two vessels. 
     
     
         24 . The on-board desulfurization system of  claim 23  wherein there is a vacuum in the gap between the two vessels. 
     
     
         25 . The on-board desulfurization system of  claim 24  wherein there is provided an electrically powered heating element within said bed of sorbent material.