System and method for treatment of gases with reducing agents generated using steam reforming of diesel fuel

Abstract

Systems and methods for treatment of a heated exhaust gas including hydrocarbons are provided. A method includes providing a first gas including a gaseous mixture of vaporized diesel fuel and steam and treating the first gas using at least one corona discharge including a combination of streamers to transform the first gas into a second gas including volatile partially oxidized hydrocarbons (PO—HC) and hydrogen gas (H 2 ), the combination of streamers including primarily surface streamers. The method also includes extracting at least a portion of vaporized diesel fuel and steam from the second gas to form a third gas and directing a combination of the third gas and the exhaust gas into a nitrogen oxides (NOx) reduction reactor.

What is claimed is: 
     
         1 . A method for treatment of a heated exhaust gas comprising hydrocarbons, the method comprising:
 providing a first gas comprising a gaseous mixture of vaporized diesel fuel and steam;   treating the first gas using at least one corona discharge comprising a combination of streamers to transform the first gas into a second gas comprising volatile partially oxidized hydrocarbons (PO—HC) and hydrogen gas (H 2 ), the combination of streamers comprising primarily surface streamers;   extracting at least a portion of vaporized diesel fuel and steam from the second gas to form a third gas;   directing a combination of the third gas and the exhaust gas into a nitrogen oxides (NOx) reduction reactor.   
     
     
         2 . The method of  claim 1 , wherein the step of providing further comprises:
 directing a liquid mixture of liquid diesel fuel and water into a heat exchanger; and   applying the heated exhaust gas to the heat exchanger to vaporize the liquid mixture and produce the first gas.   
     
     
         3 . The method of  claim 1 , wherein the step of treating further comprises:
 providing one or more discharge chambers defined by a plurality of dielectric sections, each of the discharge chambers comprising at one or more sets of first and second electrodes for producing electric fields in the discharge chambers, the plurality of dielectric sections and the sets of first and second electrodes arranged to define a volume in each of the discharge chambers that inhibits the formation of volume-streamers, and the discharge chambers being configured to prevent pulsed electric fields generated in adjacent ones of the discharge chambers from substantially interacting;   directing the first gas into the discharge chambers;   generating the corona discharge in the discharge chambers using a pulsed electric field generated by each of the sets of the first and second electrodes in the discharge chambers; and   releasing the second gas from the discharge chambers.   
     
     
         4 . The method of  claim 3 , further comprising heating the discharge chambers using the heated exhaust gas. 
     
     
         5 . The method of  claim 1 , wherein the step of extracting further comprises:
 directing the second gas into a heat exchanger;   cooling the second gas in the heat exchanger to condense water and liquid diesel fuel from the second gas.   
     
     
         6 . The method of  claim 5 , wherein the step of providing further comprises:
 forming at least a portion of the first gas using the condensed water and the condensed liquid diesel fuel.   
     
     
         7 . An exhaust system, comprising:
 a nitrogen oxides (NOx) removal reactor;   an inlet portion configured for receiving a heated exhaust gas comprising hydrocarbons and directing the heated exhaust gas into the catalytic reactor; and   a reformer system heated by the heater exhaust gas, the reformer system comprising:
 a gas treatment device for treating a first gas comprising a mixture of vaporized diesel fuel and steam using at least one corona discharge comprising a combination of streamers to transform the first gas into a second gas comprising volatile partially oxidized hydrocarbons (PO—HC) and hydrogen (H 2 ), the combination of streamers comprising primarily surface streamers, and 
 a recycling system for extracting at least a portion of vaporized diesel fuel and steam from the second gas to form a third gas and directing the third gas into the inlet portion. 
   
     
     
         8 . The system of  claim 7 , wherein the reformer system further comprises a first heat exchanger for receiving a liquid mixture of liquid diesel fuel and water and generating the first gas, wherein the first heat exchanger is configured for generating the first gas by vaporizing the liquid mixture using the heated exhaust gas. 
     
     
         9 . The system of  claim 8 , wherein the heat exchanger is disposed in the inlet portion. 
     
     
         10 . The system of  claim 8 , wherein the recycling system comprises:
 a second heat exchanger coupled to an outlet of the plasma reactor and configured for producing the third gas by condensing water and liquid diesel fuel from the second gas;   a recycle supply line for directing the condensed water and the condensed liquid diesel fuel from the second heat exchanger to the first heat exchanger; and   a reactant supply line for directing the third gas from the second heat exchanger to the inlet portion.   
     
     
         11 . The system of  claim 8 , further comprising:
 a water source for providing the water to the first heat exchanger; and   a fuel source for providing the liquid diesel fuel to the first heat exchanger.   
     
     
         12 . The system of  claim 1 , wherein the gas treatment device comprises one or more discharge chambers defined by a plurality of dielectric sections, each of the discharge chambers comprising at one or more sets of first and second electrodes for producing electric fields in the discharge chambers, wherein the plurality of dielectric sections and the sets of first and second electrodes are arranged to define a volume in each of the discharge chambers that inhibits the formation of volume-streamers, and wherein the discharge chambers being configured to prevent pulsed electric fields generated in adjacent ones of the discharge chambers from substantially interacting. 
     
     
         13 . The system of  claim 12 , further comprising heating the discharge chambers using the heated exhaust gas. 
     
     
         14 . The system of  claim 12 , wherein the discharge chambers are disposed in the inlet portion. 
     
     
         15 . The system of  claim 12 , wherein the NOx removal reactor comprises at least one of a hydrocarbon selective catalytic reduction (H-SCR) reactor and a NOx adsorbent. 
     
     
         16 . A diesel fuel powered system, comprising:
 a diesel fuel engine comprising an exhaust outlet for releasing exhaust gas;   a hydrocarbon selective catalytic reduction (H-SCR) reactor;   an inlet portion configured for directing the exhaust gas from the exhaust outlet to the H-SCR reactor;   a gas treatment device at least partially disposed in the inlet portion, the gas treatment device configured for treating a first gas comprising a mixture of vaporized diesel fuel and steam using at least one corona discharge comprising a combination of streamers to transform the first gas into a second gas comprising volatile partially oxidized hydrocarbons (PO—HC) and hydrogen (H 2 ), the combination of streamers comprising primarily surface streamers,   a first heat exchanger at least partially disposed in the inlet portion and configured for generating the first gas from water and liquid diesel fuel using a heat of the exhaust outlet;   a recycling system coupled to the plasma reactor to receive the second gas, the recycling system configured for extracting liquid diesel fuel and water from the second gas to form a third gas, directing the third gas into the inlet portion, and directing the extracted liquid diesel fuel and the extracted water into the first heat exchanger.   
     
     
         17 . The system of  claim 16 , wherein the recycling system comprises:
 a second heat exchanger coupled to an outlet of the plasma reactor and configured for producing the third gas by condensing water and liquid diesel fuel from the second gas;   a recycle supply line for directing the condensed water and the condensed liquid diesel fuel from the second heat exchanger to the first heat exchanger; and   a reactant supply line for directing the third gas from the second heat exchanger to the inlet portion.   
     
     
         18 . The system of  claim 16 , further comprising:
 a water source for providing the water to the first heat exchanger; and   a fuel source for providing the liquid diesel fuel to the first heat exchanger and the diesel fuel engine.   
     
     
         19 . The system of  claim 16 , wherein the gas treatment device comprises one or more discharge chambers defined by a plurality of dielectric sections, each of the discharge chambers comprising at one or more sets of first and second electrodes for producing electric fields in the discharge chambers, wherein the plurality of dielectric sections and the sets of first and second electrodes are arranged to define a volume in each of the discharge chambers that inhibits the formation of volume-streamers, and wherein the discharge chambers being configured to prevent pulsed electric fields generated in adjacent ones of the discharge chambers from substantially interacting. 
     
     
         20 . The system of  claim 19 , wherein the discharge chambers are disposed in the inlet portion. 
     
     
         21 . The system of  claim 16 , wherein the first heat exchanger is disposed in the inlet portion. 
     
     
         22 . An exhaust system, comprising:
 a nitrogen oxides (NOx) removal reactor;   an inlet portion configured for receiving a heated exhaust gas comprising hydrocarbons and directing the heated exhaust gas into the catalytic reactor; and   a reformer system heated by the heater exhaust gas in the inlet portion, the reformer system comprising a plasma reactor for treating a first gas comprising a mixture of vaporized diesel fuel and steam using at least one corona discharge comprising volume streamer and surface streamers to transform the first gas into a second gas comprising volatile partially oxidized hydrocarbons (PO—HC) and hydrogen (H 2 ), and a recycling system for extracting at least a portion of vaporized diesel fuel and steam from the second gas to form a third gas and for directing the third gas into the inlet portion,   wherein the plasma reactor comprises a plurality of dielectric sections defining two or more discharge chambers for treating the first gas, first and second electrodes disposed in each of the discharge chambers, and electrically conductive shield portions positioned between adjacent ones of the discharge chambers, and   wherein the plurality of dielectric sections and the first and second electrodes are arranged so that a greater portion of overall energy density within the discharge chambers is due to the surface-streamers.