Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/34—Chemical or biological purification of waste gases
  • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
  • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
  • B01D53/9404—Removing only nitrogen compounds
  • B01D53/9409—Nitrogen oxides
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
  • F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
  • F01N3/0814—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
  • F01N3/0828—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents characterised by the absorbed or adsorbed substances
  • F01N3/0842—Nitrogen oxides
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/103—Oxidation catalysts for HC and CO only
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
  • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
  • F01N3/2066—Selective catalytic reduction [SCR]
  • F01N3/2073—Selective catalytic reduction [SCR] with means for generating a reducing substance from the exhaust gases
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2251/00—Reactants
  • B01D2251/20—Reductants
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
  • F01N2240/30—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a fuel reformer
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
  • F01N2240/34—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being an electrolyser
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N2610/00—Adding substances to exhaust gases
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N2610/00—Adding substances to exhaust gases
  • F01N2610/03—Adding substances to exhaust gases the substance being hydrocarbons, e.g. engine fuel
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N2610/00—Adding substances to exhaust gases
  • F01N2610/04—Adding substances to exhaust gases the substance being hydrogen
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
  • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
  • F01N3/022—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous
  • F01N3/0222—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous the structure being monolithic, e.g. honeycombs
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/10—Internal combustion engine [ICE] based vehicles
  • Y02T10/12—Improving ICE efficiencies

Definitions

• the present disclosure is directed to a NOx reduction system and, more particularly, a NOx reduction system having a separator.
• the chemical compounds may be composed of gaseous compounds, which may include nitrogen oxides (NOx), and solid particulate matter, which may include soot.
• NOx nitrogen oxides
• the amount of pollutants emitted to the atmosphere from an engine are commonly regulated depending on the type of engine, size of engine, and/or class of engine.
• the amount of NOx in exhaust emitted to the atmosphere is one such regulated pollutant.
• One method for reducing the amount of NOx in the exhaust flow of an engine requires the introduction of a secondary fluid such as urea or ammonia into the exhaust.
• a secondary fluid such as urea
• use of a secondary fluid such as urea may increase the number of toxic nanoscale particulates present in an exhaust stream.
• Such particulates may include ammonium sulfate (NH4HSO4), ammonium nitrate (NH4NO3), and HCNO products such as ammeline, ammelide, polymeric melamine complex, and ammonium.
• NH4HSO4 ammonium sulfate
• NH4NO3 ammonium nitrate
• HCNO products such as ammeline, ammelide, polymeric melamine complex, and ammonium.
• Such nanoscale particulates are very difficult to trap before the exhaust is expelled into the atmosphere, and ongoing studies indicate that the release of such nanoscale particulates into the atmosphere is not desirable.
• An example of a system used for NOx reduction is disclosed in
• U.S. Patent No. 5,272,871 (“the '871 patent") to Oshima et a!., issued December 28, 1993.
• the '871 patent relates to a method and apparatus for reducing NOx from internal combustion engines.
• a hydrogen gas from a hydrogen generator is supplied for mixing into exhaust gases including NOx and oxygen gas at an upstream position of a catalyzer provided in an exhaust line.
• the hydrogen generator produces the hydrogen gas by electrolysis of water or water vapor. Such electrolysis is performed simultaneously with diffusion across a polymer electrolyte membrane.
• the catalyzer initiates a catalytic reaction between the hydrogen gas and NOx, resulting in nitrogen gas and water vapor.
• the NOx is then reduced with the hydrogen gas under a low temperature atmosphere of not higher than 350° C.
• the method of the '871 patent may provide a reduction of NOx in an exhaust stream, the rate at which NO gases are converted to NO 2 may be suboptimal. Suboptimal conversion occurs when the exhaust does not contain a sufficient amount of NOx reducing agents. It may be desirable to increase the rate of NOx reduction by producing a greater amount of H 2 in an exhaust stream. Such an increase of H 2 will advance conversion of NO gases to NO 2 through oxidation. Further, the system of the '871 patent may be limited to low temperature atmospheric conditions. Therefore, the system may quickly degrade in the extreme conditions produced by an engine. The disclosed exhaust system is directed to overcoming one or more of the problems set forth above.
• the present disclosure is directed to a method of reducing NOx in a flow of high temperature engine exhaust including directing a portion of a flow of high temperature exhaust from an exhaust manifold of an engine to a separator. The method further includes separating steam from the flow of high temperature exhaust with the separator and using components of the separated steam to reduce NOx in the high temperature exhaust.
• the present disclosure is directed to a method of reducing NOx in a flow of engine exhaust including directing the flow of exhaust from the engine to a separator. The method further includes separating steam and CO from the flow of exhaust with the separator and forming CO 2 and H 2 using the separated CO and steam.
• the present disclosure is directed to a method of reducing NOx in a flow of high temperature engine exhaust including passing at least a portion of the flow of high temperature exhaust through a separator.
• the method further includes separating steam from the flow of high temperature exhaust with the separator and using the separated steam in a high temperature electrolysis reactor to form H 2 and O 2 .
• the method also includes reducing NOx in the high temperature exhaust with the formed H 2 .
• the present disclosure is directed to a method of reducing NOx in a flow of engine exhaust including separating steam from the flow of exhaust with a separator.
• the method further includes mixing the separated steam with a hydrocarbon fuel to form H 2 and reducing NOx in the exhaust with the formed H 2 .
• the present disclosure is directed to a system including a combustion engine, an engine exhaust manifold, and a separator positioned downstream of the engine exhaust manifold in an exhaust flow path.
• the separator is configured to extract steam from exhaust in the exhaust flow path.
• the system also includes an element configured to receive the extracted steam and produce a NOx reducing agent.
• Fig. 1 is an illustration of an exemplary disclosed NOx reduction system including a water gas shift reactor.
• Fig. 2 is an illustration of an exemplary disclosed NOx reduction system including a high temperature electrolysis reactor.
• Fig. 3 is an illustration of an exemplary disclosed NOx reduction system including a steam reforming reactor.
• Fig. 4 is a flow chart illustration of an exemplary disclosed method of operating the NOx reduction system of Fig. 1.
• Fig. 5 is a flow chart illustration of an exemplary disclosed method of operating the NOx reduction system of Fig. 2.
• Fig. 6 is a flow chart illustration of an exemplary disclosed method of operating the NOx reduction system of Fig. 3.
• Fig. 1 illustrates an exemplary power system 10.
• Power system 10 is described herein with respect to a diesel-fuel, internal combustion engine 12 for exemplary purposes only. It is contemplated that engine 12 may embody any other type of engine, such as, for example, a gasoline engine, a natural gas engine, and an external combustion engine.
• Engine 12 may include an engine block 14 at least partially defining a plurality of cylinders 16. Each cylinder 16 may be associated with, for example, a fuel injector, an engine inlet manifold 18, an engine exhaust manifold 20, and a reciprocating piston assembly moveable within each cylinder 16.
• engine 12 may include any number of cylinders 16, and that cylinders 16 may be disposed in an "in-line” configuration, a “V” configuration, or any other conventional configuration.
• a crankshaft 22 of engine 12 may be rotatably disposed within engine block 14.
• Power system 10 may be used with a machine.
• the machine may embody a mobile or stationary machine that performs some type of operation associated with an industry such as mining, construction, farming, transportation, or any other industry known in the art.
• the machine may be an earth moving machine such as an off-highway haul truck, a wheel loader, a motor grader, or any other suitable earth moving machine.
• the machine may alternatively embody an on-highway vocational truck, a passenger vehicle, or any other operation-performing machine.
• Power system 10 may include an air induction system 30.
• Air induction system 30 may be associated with power system 10 and may include components that condition and introduce compressed air into cylinder 16 by way of inlet manifold 18.
• air induction system 30 may include an air filter 32, and a compressor 34 connected to draw inlet air through air filter 32. It is contemplated that air induction system 30 may include different or additional components that are conventionally known in the art.
• Compressor 34 may be located downstream of air filter 32 and configured to compress the air flowing into power system 10. Compressor 34 may be any type of compressor known in the art. Power system 10 may optionally include an exhaust gas recirculation system (EGR) (not shown). An EGR system may be used for controlling emissions of undesirable pollutant gases and particulates during operation of an internal combustion engine as is known in the art.
• EGR exhaust gas recirculation system
• Power system 10 may further include an exhaust system 40 including an aftertreatment system 50.
• Exhaust system 40 may include a turbine 52 positioned to receive exhaust leaving power system 10 via exhaust manifold 20.
• Turbine 52 may be connected to compressor 34 of air induction system 30 by way of a common shaft to form a turbocharger. As the hot exhaust gases exiting power system 10 move through turbine 52 and act upon turbine 52, i.e., expand against vanes (not shown), turbine 52 may rotate and drive compressor 34 to pressurize inlet air. It is contemplated that more than one turbine 52 may be included within exhaust system 40 and disposed in parallel or in series relationship.
• Aftertreatment system 50 may include components that condition and direct exhaust along exhaust system 40 as it exits turbine 52. As shown in Fig. 1, for example, aftertreatment system 50 may include a direct oxidation catalyst (DOC) 54, a diesel particulate filter (DPF) 56, and a NOx reduction trap (NRT) 58.
• DOC direct oxidation catalyst
• DPF diesel particulate filter
• NRT NOx reduction trap
• DOC 54 may be positioned to receive exhaust exiting turbine 52.
• DOC 54 may convert pollutants in the exhaust stream into more environmentally friendly components.
• DOC 54 may utilize a catalyst, such as a transition metal catalyst, to reduce particulate matter in the exhaust stream through oxidation.
• DPF 56 may be located downstream of, and in fluid communication with, DOC 54.
• DPF 56 may include any type of filter known in the art, such as, for example, a foam cordierite, sintered metal, ceramic, or silicon carbide type filter. At least a portion of DPF 56 may be arranged into a honeycomb, mesh, and/or other suitable configuration in order to filter or trap particulate matter in the exhaust stream as it passes through DPF 56.
• DPF 56 may contain catalyst materials, including, for example, aluminum, platinum, rhodium, barium, cerium, and/or alkali metals, alkaline-earth metals, rare-earth metals, or combinations thereof.
• NRT 58 may be provided downstream of DPF 56 to convert NOx pollutants in the exhaust stream into more environmentally friendly components.
• NRT 58 may be, for example, a selective catalytic reduction trap (SCR) in which a reductant is used to convert NOx into more environmentally friendly components.
• SCR selective catalytic reduction trap
• NRT 58 may be, for example, a lean NOx trap (LNT) in which a washcoat containing zeolites is used to convert NOx into more environmentally friendly components.
• LNT lean NOx trap
• Aftertreatment system 50 also may include a separator 60, configured to separate certain elements from the exhaust stream, such as, for example, CO and steam.
• Separator 60 may be, for example, a membrane, a porous element, or a tubular device arranged in a honeycomb, mesh, and/or other suitable configuration in order to extract selected components from the exhaust.
• Separator 60 may be positioned in proximity to exhaust manifold 20 and, in such instances, may be made of materials capable of withstanding the temperatures associated with such positioning.
• separator 60 may be ceramic, metallic or any other known material capable of withstanding high temperatures, for example, temperatures up to 400-800° C, specifically 500-600° C. Separator 60 will be described as a membrane in the remainder of this disclosure for exemplary purposes only. Such a description should not be considered limiting.
• membrane 60 may be positioned downstream of exhaust manifold 20 and upstream of turbine 52. Pores (not shown) of membrane 60 may be sized to extract steam and CO from the exhaust.
• pores of membrane 60 may be sized to have a diameter which allows for a diffusion volume of at least 63.41 cm 3 /g-mol. Such a pore size may be large enough to pass both steam and CO molecules while restricting passage of larger exhaust molecules. Extraction across membrane 60 may be driven by the pressure of the exhaust exiting exhaust manifold 20.
• membrane 60 may be positioned downstream of turbine 52. In such a position, it may be desirable to include a pump (not shown) to drive extraction across membrane 60.
• Aftertreatment system 50 also may include a water gas shift reactor (WGSR) 70 positioned to receive the steam and CO extracted from the exhaust by membrane 60. Extracted steam and CO may be, for example, directed to WGSR 70 by the pressure of the exhaust exiting exhaust manifold 20.
• WGSR 70 may comprise, for example, a solid copper enclosure.
• WGSR 70 may comprise, for example, an enclosure including a copper based coating. The copper or copper based coating may act as a catalyst, initiating or facilitating chemical reactions within the enclosure.
• WGSR 70 utilizes the extracted steam and CO to produce a chemical reaction forming CO 2 and H 2 . These components may then be directed to NRT 58 for use as NOx reducing agents within the exhaust system 40.
• exhaust system 40 may include turbine 152 and aftertreatment system 150.
• aftertreatment system 150 may include a direct oxidation catalyst (DOC) 154, a diesel particulate filter (DPF) 156, a NOx reduction trap (NRT) 158, and membrane 160.
• DOC direct oxidation catalyst
• DPF diesel particulate filter
• NRT NOx reduction trap
• membrane 160 may be positioned downstream of exhaust manifold 20 and upstream of turbine 152.
• Membrane 160 may include pores (not shown), sized to extract steam from the exhaust. Therefore, pores of membrane 160 may be sized to have a diameter which allows for a diffusion volume of at least 23.25 cm 3 /g-mol. Such a pore size is large enough to allow steam molecules to pass while restricting passage of larger exhaust molecules. Extraction across membrane 160 may be driven by the pressure of the exhaust exiting exhaust manifold 20.
• membrane 160 may be positioned downstream of turbine 152. In such a position, it may be desirable to include a pump (not shown) to drive extraction across membrane 160.
• aftertreatment system 150 may additionally include a high temperature electrolysis reactor (HTER) 180 positioned to receive the extracted steam and electrolyze it into H 2 and O 2 .
• Extracted steam may be, for example, directed to HTER 180 by the pressure of the exhaust exiting exhaust manifold 20.
• HTER 180 may be comprised of an enclosure including a precious metal based catalyst to aid in the electrolysis of the extracted steam.
• aftertreatment system 150 also may include a generator 182 and a battery 184.
• Generator 182 may be positioned to convert mechanical energy from crankshaft 22 of engine 12 into electrical energy. The generated electrical energy may be supplied to battery 184 and similarly, to HTER 180 via appropriate electrical connections.
• Battery 184 may be any appropriate battery, including, but not limited to, any onboard battery of the machine.
• Aftertreatment system 150 may also include a second separating element, separator 186, positioned to receive the electro lyzed H 2 and O 2 .
• Separator 186 may be, for example, a membrane or a tubular device arranged in a honeycomb, mesh, and/or other suitable configuration in order to allow separator 186 to divide the H 2 and O 2 received from HTER 180.
• These components may then be directed to various elements of exhaust system 40 to be used as NOx reducing agents.
• the H 2 may be directed to NRT 158 via a first pathway and the O 2 may be directed to DOC 154 via a second pathway.
• exhaust system 40 may include turbine 252 and aftertreatment system 250.
• aftertreatment system 250 may include a direct oxidation catalyst (DOC) 254, a diesel particulate filter (DPF) 256, a NOx reduction trap (NRT) 258, and a membrane 260.
• DOC direct oxidation catalyst
• DPF diesel particulate filter
• NRT NOx reduction trap
• membrane 260 may be positioned downstream of exhaust manifold 20 and upstream of turbine 252.
• Membrane 260 may include pores (not shown), sized to extract steam from the exhaust. Therefore, pores of membrane 160 may have a diameter which allows for a diffusion volume of at least 23.25 cm 3 /g-mol. Such a pore size is large enough to allow steam molecules to pass while restricting passage of larger exhaust molecules. Extraction across membrane 260 may be driven by the pressure of the exhaust exiting exhaust manifold 20.
• membrane 260 may be positioned downstream of turbine 252. In such a position, it may be desirable to include a pump (not shown) to drive extraction across membrane 260. As shown in Fig.
• aftertreatment system 250 additionally may include a steam reforming reactor (SRR) 290 positioned to receive the extracted steam from membrane 260.
• Aftertreatment system 250 also may include an injector 292 configured to inject hydrocarbon fuel into SRR 290 to facilitate a reaction within SRR 290 to form H 2 and CO.
• Extracted steam may, for example, be directed to SRR 290 by the pressure of the exhaust exiting exhaust manifold 20.
• SRR 290 may comprise an enclosure including a rhodium, platinum, or nickel based catalyst to aid in the formation of H 2 and CO. These components are used as NOx reducing agents within the exhaust system 40.
• the hydrocarbon fuel may, for example, be supplied from fuel source 294.
• Fuel source 294 may be the same fuel source used by engine 12.
• the H 2 and CO formed within SRR 290 may be directed, for example, to NRT 258 for use in reducing NOx within the exhaust.
• Figs. 4-6 are flow charts illustrating various methods of operating the aftertreatment systems 50, 150, 250 of Figs. 1-3, respectively. Figs. 4-6 will be discussed in greater detail below.
• the disclosed NOx reduction system may be provided in any machine or powered system that includes a power source producing a flow of exhaust, such as an engine.
• the disclosed NOx reduction system may increase the amount of NO 2 relative to NO in the flow of exhaust, thereby reducing the amount of environmentally harmful pollutants exhausted to the atmosphere.
• the operation of the exhaust aftertreatment systems 50, 150, 250 will now be explained.
• Atmospheric air may be drawn into air induction system 30 via air filter 32, and may be directed through compressor 34 where it may be pressurized to a predetermined level before entering the combustion chamber of engine 12.
• Fuel may be mixed with the pressurized air before or after entering the combustion chamber of engine 12.
• the fuel and air mixture may be ignited by engine 12 to produce mechanical work and an exhaust flow containing gaseous compounds.
• the exhaust flow may be a fluid containing solid particulate matter and pollutants such as, for example, carbon, sulfur, and NOx.
• the exhaust flow may be directed from engine 12 along exhaust system 40 to turbine 52, 152, 252 where the expansion of hot exhaust gases may cause turbine 52, 152, 252 to rotate, thereby rotating connected compressor 34, causing compressor 34 to compress the inlet air.
• Exhaust exiting turbine 52, 152, 252 may flow along exhaust system 40 through aftertreatment system 50, 150, 250. As exhaust passes through the aftertreatment system 50, 150, 250, the exhaust may undergo a series of chemical reactions that will reduce the amount of NOx in the exhaust that is ultimately released to the atmosphere. Alternate exemplary pathways in the exemplary aftertreatment systems 50, 150, 250 disclosed in Figs. 1-3 are discussed more fully below.
• Fig. 4 is a flow diagram illustrating an exemplary disclosed method for operating the aftertreatment system 50 of Fig. 1.
• a portion of the exhaust may be directed through membrane 60.
• Membrane 60 may be configured to extract at least some steam and CO from the flow of exhaust (Step 100).
• Such a configuration can be achieved by appropriately sizing the molecular diameter of the pores of membrane 60 to allow certain exhaust molecules of a like, or smaller molecular diameter to pass, while restricting passage of larger sized exhaust molecules.
• Extracted steam and CO are then directed to WGSR 70 in which the extracted steam and CO react to form CO 2 and H 2 (Step 110), facilitated or initiated by, for example, copper or a copper based coating of WGSR 70, according to the following chemical reaction:
• WGSR 70 may be positioned in close proximity to exhaust manifold 20. Such an arrangement will allow WGSR 70 to utilize the relatively high temperature exhaust exiting exhaust manifold 20 to produce sufficient H 2 at a faster reaction rate.
• the H 2 formed in WGSR 70 may be used as a reducing agent and may be directed to NRT 58 where its presence will aid in converting NOx pollutants in the exhaust traveling along exhaust system 40 into more environmentally friendly components.
• the H 2 may react with NOx to form steam and N 2 .
• the H 2 and CO 2 formed in WGSR 70 may be directed by the pressure of the exhaust exiting exhaust manifold 20. Alternatively, a pump or other suitable means may be used to direct these elements through exhaust system 40.
• a portion of the exhaust exiting exhaust manifold 20 may be directed through membrane 60. Exhaust not directed through membrane 60 may travel through turbine 52 and drive compressor 34 (Step 115). Exhaust exiting turbine 52 may travel to aftertreatment system 50 including DOC 54, where at least a portion of the pollutants in the exhaust stream, including but not limited to particulate matter, may be oxidized into more environmentally friendly components (Step 120). After exiting DOC 54, exhaust may pass through DPF 56, where at least a portion of remaining particulate matter in the exhaust may be trapped within DPF 56 (Step 130). Exhaust exiting DPF 56 then may flow to NRT 58 where a reduction in NOx may be achieved by converting NOx pollutants in the exhaust stream into more environmentally friendly components (Step 140).
• Elements such as NOx within the exhaust may react with the CO 2 and H 2 directed to NRT 58 from WGSR 70.
• reductant such as anhydrous ammonia, aqueous ammonia or urea
• NOx in NRT 58 may react with the CO 2 and H 2 directed to NRT 58 from WGSR 70.
• reductant such as anhydrous ammonia, aqueous ammonia or urea
• a washcoat containing zeolites may react with NOx in NRT 58 to form more environmentally friendly components.
• Exhaust elements may react with the reductant and/or washcoat with or without the presence of the formed CO 2 and H 2 .
• the treated exhaust After passing through aftertreatment system 50, the treated exhaust may be released to the surrounding atmosphere (step 145).
• Fig. 5 is a flow diagram illustrating an alternative, exemplary disclosed method for operating the aftertreatment system 150 of Fig. 2.
• a portion of the exhaust may be directed through membrane 160.
• Membrane 160 may be configured to extract at least some steam from the flow of exhaust (Step 200).
• Such a configuration can be achieved by appropriately sizing the molecular diameter of the pores of membrane 160 to allow certain exhaust molecules of a like, or smaller molecular diameter to pass, while restricting passage of larger exhaust molecules.
• Extracted steam is then directed to HTER 180 in which the extracted steam is electrolyzed to form H 2 and O 2 (Step 210) according to the following chemical equation:
• HTER 180 may be positioned in close proximity to exhaust manifold 20. Such an arrangement will allow HTER 180 to utilize waste energy in the exhaust stream, making aftertreatment system 150 increasingly efficient. Electrolysis requires the introduction of an electric current. Such an electrical current may be supplied by generator 182 and battery 184. As mentioned above, generator 182 may be positioned to convert mechanical energy from crankshaft 22 of engine 12 into electrical energy. The generated electrical energy may be supplied to battery 184 and, similarly, to HTER 180 via appropriate electrical connections. Battery 184 may be any appropriate battery, including, but not limited to, any onboard battery of the machine. The electro lyzed H 2 and O 2 may be directed to and divided by separator 186.
• the H 2 formed in HTER 180 may be directed to NRT 158 where its presence will aid in converting NOx pollutants in the exhaust traveling along exhaust system 40 into more environmentally friendly components. For example, the H 2 may react with NOx to form steam and N 2 . Similarly, the O 2 formed in HTER 180 may be directed to DOC 154 to aid in oxidation of particulate matter in the exhaust traveling along exhaust system 40. The H 2 and O 2 formed in HTER 180 may be directed to NRT 158 and DOC 154, respectively, by the pressure of the exhaust exiting exhaust manifold 20. Alternatively, a pump or other suitable means may be used to direct these elements through exhaust system 40.
• a portion of the exhaust exiting exhaust manifold 20 may be directed through membrane 160. Exhaust not directed through membrane 160 may travel through turbine 152 and drive compressor 34 (Step 215). Exhaust exiting turbine 152 may travel to aftertreatment system 150 including DOC 54, where at least a portion of the pollutants in the exhaust stream, including but not limited to particulate matter, may be oxidized into more environmentally friendly components (Step 220). After exiting DOC 154, exhaust may pass through DPF 156, where at least a portion of remaining particulate matter in the exhaust may be trapped within DPF 156 (Step 230).
• Exhaust exiting DPF 156 then may flow to NRT 158 where a reduction in NOx may be achieved by converting NOx pollutants in the exhaust stream into more environmentally friendly components (Step 240).
• Elements such as NOx within the exhaust may react with the H 2 directed to NRT 158 from HTER 180.
• reductant such as anhydrous ammonia, aqueous ammonia or urea
• reductant such as anhydrous ammonia, aqueous ammonia or urea
• a washcoat containing zeolites may react with NOx in NRT 158 to form more environmentally friendly components.
• Exhaust elements may react with the reductant and/or washcoat with or without the presence of the formed H 2 .
• the treated exhaust After passing through aftertreatment system 150, the treated exhaust may be released to the surrounding atmosphere (step 245).
• Fig. 6 is a flow diagram illustrating an alternative, exemplary disclosed method for operating the aftertreatment system 250 of Fig. 3.
• a portion of the exhaust may be directed through membrane 260.
• Membrane 260 may be configured to extract at least some steam from the flow of exhaust (Step 300).
• Such a configuration can be achieved by appropriately sizing the molecular diameter of the pores of membrane 260 to allow certain exhaust molecules of a like, or smaller molecular diameter to pass while restricting passage of larger exhaust molecules.
• Extracted steam is then directed to SRR 290 in which the extracted steam is combined with an injected hydrocarbon fuel (Step 310) according to the following endothermic chemical equation: 1.5n H 2 O + CnH 2n ⁇ 0.5nCO 2 + 0.5nCO + 1.5nH 2 (3)
• the hydrocarbon based fuel required by this reaction may be injected via injector 292. Also, the hydrocarbon based fuel required may be supplied from the same fuel source used by engine 12, thereby eliminating the need for additional infrastructure. Alternatively, a separate fuel source may be provided. Endothermic chemical reactions require heat to be performed. As such, it is envisioned that SRR 290 may be positioned in close proximity to exhaust manifold 20. Such an arrangement will allow SRR 290 to utilize waste energy in the exhaust stream, making aftertreatment system 250 increasingly efficient. Furthermore, since endothermic reactions absorb heat, placing the SRR 290 in close proximity to exhaust manifold 20 may reduce the temperature of exhaust leaving exhaust manifold 20. Such a reduction in temperature may increase the durability of exhaust manifold 20, as well as other downstream components.
• the CO and H 2 formed in SRR 290 may be directed to NRT 258 where their presence will aid in converting NOx pollutants in the exhaust traveling along exhaust system 40 into more environmentally friendly components.
• the H 2 may react with NOx to form steam and N 2 .
• the CO and H 2 formed in SRR 290 may be directed by the pressure of the exhaust exiting exhaust manifold 20. Alternatively, a pump or other suitable means may be used to direct these elements through exhaust system 40.
• a portion of the exhaust exiting exhaust manifold 20 may be directed through membrane 260. Exhaust not directed through membrane 260 may travel through turbine 252 and drive compressor 34 (Step 315). Exhaust exiting turbine 252 may travel to aftertreatment system 250 including DOC 254, where at least a portion of the pollutants in the exhaust stream, including but not limited to particulate matter, may be oxidized into more environmentally friendly components (Step 320). After exiting DOC 254, exhaust may pass through DPF 256, where at least a portion of remaining particulate matter in the exhaust may be trapped within DPF 256 (Step 330).
• Exhaust exiting DPF 256 then may flow to NRT 258 where a reduction in NOx may be achieved by converting NOx pollutants in the exhaust stream into more environmentally friendly components (Step 340).
• Elements such as NOx within the exhaust may react with the H 2 and CO directed to NRT 258 from SRR 290.
• reductant such as anhydrous ammonia, aqueous ammonia or urea
• reductant such as anhydrous ammonia, aqueous ammonia or urea
• a washcoat containing zeolites may react with NOx in NRT 258 to form more environmentally friendly components.
• Exhaust elements may react with the reductant and/or washcoat with or without the presence of the formed H 2 and CO.
• the treated exhaust After passing through aftertreatment system 250, the treated exhaust may be released to the surrounding atmosphere (step 350).

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• 2009
  • 2009-12-18 WO PCT/US2009/068690 patent/WO2010075205A2/en active Application Filing
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