Emission treatment system and method of operation

Abstract

An emission treatment system is provided. The emission treatment system comprises a separation system and a selective catalytic reduction (SCR) catalyst. The separation system comprises a separator, a fuel inlet disposed to supply fuel to the separator, a first fuel outlet and a second fuel outlet respectively disposed to carry away fuel from the separator. The SCR catalyst comprises a catalyst composition comprising silver and templated metal oxide substrate. The emission treatment system is designed such that the separation system is configured to be in fluid communication with the SCR catalyst through the first fuel outlet during operation. A system including the emission treatment system and a combustion engine is also provided. Method of increasing NOx reduction efficiency of the SCR catalyst using fuel fraction is discussed.

1 . An emission treatment system comprising:
 a separation system comprising a separator, a fuel inlet disposed to supply fuel to the separator, a first fuel outlet and a second fuel outlet respectively disposed to carry away fuel from the separator; and   a selective catalytic reduction (SCR) catalyst comprising a catalyst composition comprising silver and templated metal oxide substrate,   wherein the separation system is configured to be in fluid communication with the SCR catalyst through the first fuel outlet during operation.   
     
     
         2 . The emission treatment system of  claim 1 , wherein the separator comprises a flash heater. 
     
     
         3 . The emission treatment system of  claim 1 , wherein the separator comprises a distillation unit. 
     
     
         4 . The emission treatment system of  claim 1 , wherein the separator comprises a membrane. 
     
     
         5 . The emission treatment system of  claim 1 , wherein the separator comprises a heat exchanger. 
     
     
         6 . The emission treatment system of  claim 1 , wherein the separator comprises a bubbling column. 
     
     
         7 . The emission treatment system of  claim 1 , wherein the templated metal oxide comprises alumina or silica-alumina. 
     
     
         8 . The emission treatment system of  claim 1 , wherein the catalyst composition has a surface area in the range of about 250 to about 600 m 2 /gm. 
     
     
         9 . The emission treatment system of  claim 1 , wherein the templated metal oxide has periodically arranged templated pores, wherein the average diameter of the pores is in a range of from about 2 nanometers to about 100 nanometers and the pores have a periodicity in a range of from about 50 Angstrom to about 130 Angstrom. 
     
     
         10 . The emission treatment system of  claim 1 , wherein the substrate further comprises an additional dopant material selected from the group consisting of zirconium, yttrium, iron, gallium, indium, tungsten, zinc, platinum, and rhodium. 
     
     
         11 . The emission treatment system of  claim 1 , wherein the separator is configured to receive fuel through the fuel inlet, separate the fuel into a first fraction having a maximum boiling point at a temperature that is in the range from about 70 degrees Celsius to about 360 degrees Celsius and a second fraction of fuel having a boiling point above said temperature, and dispose the first fraction into the first fuel outlet. 
     
     
         12 . The emission treatment system of  claim 11 , wherein the maximum boiling point is at a temperature that is in the range from about 100 degrees Celsius to about 225 degrees Celsius. 
     
     
         13 . The emission treatment system of  claim 12 , wherein the temperature is about 225 degrees Celsius. 
     
     
         14 . The emission treatment system of  claim 1 , wherein the separator is configured to receive fuel through the fuel inlet, separate the fuel into a first fraction having a minimum boiling point at a temperature that is in the range from about 70 degrees Celsius to about 360 degrees Celsius and a second fraction of fuel having a boiling point below said temperature, and dispose the first fraction into the first fuel outlet. 
     
     
         15 . The emission treatment system of  claim 14 , wherein the minimum boiling point is at a temperature that is in the range from about 300 degrees Celsius to about 360 degrees Celsius. 
     
     
         16 . The emission treatment system of  claim 1 , wherein the separation system comprises a first separator and a second separator, and wherein the first fuel outlet of the first separator is the fuel inlet of the second separator. 
     
     
         17 . A system comprising:
 a fuel tank adapted to supply a fuel;   a combustion engine configured to receive the fuel and create an exhaust stream; and   an emission treatment system configured to receive at least a portion of the exhaust stream wherein the emission treatment system comprises:
 a separation system comprising a fuel inlet disposed to receive fuel from the fuel tank, a separator configured to receive fuel through the fuel inlet, a first fuel outlet and a second fuel outlet respectively disposed to carry away fuel from the separator; and 
 an SCR catalyst comprising a catalyst composition comprising silver and a templated metal oxide substrate, 
   wherein the separation system is in fluid communication with the SCR catalyst through the first fuel outlet.   
     
     
         18 . The system of  claim 17 , wherein the separation system is in fluid communication with the combustion engine through the second fuel outlet. 
     
     
         19 . The system of  claim 17 , wherein the separator comprises a flash heater. 
     
     
         20 . The system of  claim 17 , wherein the separator comprises a distillation unit. 
     
     
         21 . The system of  claim 17 , wherein the templated metal oxide comprises alumina or silica-alumina. 
     
     
         22 . The system of  claim 17 , wherein the catalyst composition has a surface area in the range of about 250 to about 600 m 2 /gm. 
     
     
         23 . The system of  claim 17 , wherein the templated metal oxide has periodically arranged templated pores, wherein the average diameter of the pores is in a range of from about 2 nanometers to about 100 nanometers and the pores have a periodicity in a range of from about 50 Angstrom to about 130 Angstrom. 
     
     
         24 . The system of  claim 17 , wherein the substrate further comprises an additional dopant material selected from the group consisting of zirconium, yttrium, iron, gallium, indium, tungsten, zinc, platinum, and rhodium. 
     
     
         25 . The system of  claim 17 , wherein the separator is configured to receive fuel through the fuel inlet, separate the fuel into a first fraction having a maximum boiling point at a temperature that is in the range from about 70 degrees Celsius to about 350 degrees Celsius and a second fraction having a boiling point above said temperature, and dispose the first fraction into the first fuel outlet. 
     
     
         26 . The system of  claim 25 , wherein the maximum boiling point is at a temperature that is in the range from about 100 degrees Celsius to about 225 degrees Celsius. 
     
     
         27 . The system of  claim 26 , wherein the maximum boiling point is at a temperature that is in the range from about 150 degrees Celsius to about 200 degrees Celsius. 
     
     
         28 . The system of  claim 17 , wherein the separator is configured to receive fuel through the fuel inlet, separate the fuel into a first fraction having a minimum boiling point at a temperature that is in the range from about 70 degrees Celsius to about 350 degrees Celsius and a second fraction having a boiling point below said temperature, and dispose the first fraction into the first fuel outlet. 
     
     
         29 . The system of  claim 28 , wherein the minimum boiling point is at a temperature that is in the range from about 300 degrees Celsius to about 360 degrees Celsius. 
     
     
         30 . A system comprising:
 a fuel tank adapted to supply a fuel;   a combustion engine configured to receive the fuel and create an exhaust stream; and   an emission treatment system configured to receive at least a portion of the exhaust stream wherein the emission treatment system comprises:
 a separation system comprising:
 a fuel inlet disposed to receive fuel from the fuel tank, 
 a separator configured to receive fuel through the fuel inlet, separate the fuel using a flash heater to a first fraction having a maximum boiling point at a temperature that is in the range from about 70 degrees Celsius to about 360 degrees Celsius and a second fraction having a boiling point above said temperature range, dispose the first fraction from the separator to a first fuel outlet, and dispose the second fraction from the separator to a second fuel outlet; and 
 
 an SCR catalyst comprising a catalyst composition comprising silver and a templated metal oxide substrate, 
   wherein the separation system is in fluid communication with the SCR catalyst and combustion engine through the first fuel outlet and second fuel outlet, respectively.   
     
     
         31 . A system comprising:
 a fuel tank adapted to supply a fuel;   a combustion engine configured to receive the fuel and create an exhaust stream; and   an emission treatment system configured to receive at least a portion of the exhaust stream wherein the emission treatment system comprises:
 a separation system comprising:
 a fuel inlet disposed to receive fuel from the fuel tank, 
 a separator configured to receive fuel through the fuel inlet, separate the fuel using a flash heater to a first fraction having a minimum boiling point at a temperature that is in the range from about 70 degrees Celsius to about 360 degrees Celsius and a second fraction having a boiling point below said temperature range, dispose the first fraction from the separator to a first fuel outlet, and dispose the second fraction from the separator to a second fuel outlet; and 
 
 an SCR catalyst comprising a catalyst composition comprising silver and a templated metal oxide substrate, 
   wherein the separation system is in fluid communication with the SCR catalyst and combustion engine through the first fuel outlet and second fuel outlet, respectively.   
     
     
         32 . A method of reducing nitrogen oxides in an exhaust stream, comprising:
 passing a fuel through a fuel inlet of a separation system;   fractionating the fuel into a first fraction and a second fraction using a separator in the separation system, wherein the first fraction has a different average boiling point than the second fraction;   passing the first fraction through a first fuel outlet of the separation system to an SCR catalyst comprising a catalyst composition comprising silver and a templated metal oxide substrate; and   passing a second fraction through a second fuel outlet of the separation system to a combustion engine,   wherein the combustion engine is configured to create the exhaust stream and the SCR catalyst reduces nitrogen oxides present in the exhaust stream created by the combustion engine.   
     
     
         33 . The method of  claim 32 , wherein the catalyst composition reduces the nitrogen oxides at a temperature greater than about 275 degrees Celsius. 
     
     
         34 . The method of  claim 32 , wherein the fuel comprises at least one element selected from the group consisting of diesel fuel, ULSD, biodiesel fuel, Fischer-Tropsch fuel, gasoline, kerosene, and ethanol. 
     
     
         35 . The method of  claim 32 , wherein the fuel comprises at least one of ultra low sulfur diesel fuel and biodiesel. 
     
     
         36 . The method of  claim 32 , wherein the fuel comprises ultra low sulfur diesel fuel. 
     
     
         37 . The method of  claim 32 , wherein the first fraction in first fuel outlet comprises lower boiling point fuel than the second fraction. 
     
     
         38 . The method of  claim 37 , wherein the first fraction comprises at least one compound selected from the group consisting of an alcohol, kerosene, and ester. 
     
     
         39 . The method of  claim 37 , wherein the first fraction comprises the fuel in a vapor state. 
     
     
         40 . The method of  claim 37 , wherein the first fraction has a maximum boiling point less than about 360 degrees Celsius. 
     
     
         41 . The method of  claim 40 , wherein the maximum boiling point is in the range from about 100 degrees Celsius to about 225 degrees Celsius. 
     
     
         42 . The method of  claim 32 , wherein the first fraction in first fuel outlet comprises higher boiling point fuel than the second fraction. 
     
     
         43 . The method of  claim 42 , wherein the first fraction comprises biodiesel. 
     
     
         44 . The method of  claim 42 , wherein the first fraction comprises the fuel in a liquid state. 
     
     
         45 . The method of  claim 42 , wherein the first fraction has a minimum boiling point greater than about 250 degrees Celsius. 
     
     
         46 . The method of  claim 45 , wherein the minimum boiling point is in the temperature range from about 300 degrees Celsius to about 360 degrees Celsius.