US20150315944A1 - Aftertreatment System for Simultaneous Emissions Control in Stationary Rich Burn Engines - Google Patents
Aftertreatment System for Simultaneous Emissions Control in Stationary Rich Burn Engines Download PDFInfo
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- US20150315944A1 US20150315944A1 US14/798,723 US201514798723A US2015315944A1 US 20150315944 A1 US20150315944 A1 US 20150315944A1 US 201514798723 A US201514798723 A US 201514798723A US 2015315944 A1 US2015315944 A1 US 2015315944A1
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- 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
- B01D53/9495—Controlling the catalytic process
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- 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
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- 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
- F01N3/101—Three-way catalysts
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- 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
- F01N3/105—General auxiliary catalysts, e.g. upstream or downstream of the main catalyst
- F01N3/106—Auxiliary oxidation catalysts
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- 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
- F01N3/22—Control of additional air supply only, e.g. using by-passes or variable air pump drives
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- 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
- F01N3/24—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 constructional aspects of converting apparatus
- F01N3/30—Arrangements for supply of additional air
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- 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
- F01N9/00—Electrical control of exhaust gas treating apparatus
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- 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
- F01N2370/00—Selection of materials for exhaust purification
- F01N2370/02—Selection of materials for exhaust purification used in catalytic reactors
- F01N2370/04—Zeolitic material
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- 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
- F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
- F01N2570/14—Nitrogen oxides
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- 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
- F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
- F01N2570/18—Ammonia
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- 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
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/06—Parameters used for exhaust control or diagnosing
- F01N2900/16—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust apparatus, e.g. particulate filter or catalyst
- F01N2900/1616—NH3-slip from catalyst
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- 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
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- 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
- Y02T10/40—Engine management systems
Definitions
- the present disclosure relates to emissions controls for internal combustion engines generally and in particular to methods and systems for simultaneous emissions control in stationary rich burn engines.
- a rich-burn engine may operate with a stoichiometric amount of fuel or a slight excess of fuel, while a lean-burn engine operates with an excess of oxygen (O 2 ) compared to the amount required for stoichiometric combustion.
- the operation of an internal combustion engine in lean mode may reduce throttling losses and may take advantage of higher compression ratios thereby providing improvements in performance and efficiency.
- Rich burn engines have the benefits of being relatively simple, reliable, stable, and adapt well to changing loads. Rich burn engines may also have lower nitrogen oxide emissions, but at the expense of increased emissions of other compounds.
- Catalysts may reduce emissions of the nitrogen oxides NO and NO 2 (collectively NOx), carbon monoxide (CO), ammonia (NH 3 ), methane (CH 4 ), other volatile organic compounds (VOC), and other compounds and emissions components by converting such emissions components to less toxic substances. This conversion is performed in a catalyst component using catalyzed chemical reactions. Catalysts can have high reduction efficiencies and can provide an economical means of meeting emissions standards (often expressed in terms of grams of emissions per brake horsepower hour (g/bhp-hr)).
- Separate catalyst components or devices may be included in the exhaust pathway of a rich burn engine to convert different emissions components. For example, one catalyst component may convert carbon monoxide and NOx while another may convert ammonia and methane.
- a catalyst component may convert carbon monoxide and NOx generated by an engine into ammonia, which may then be converted by another catalyst component.
- controlling carbon monoxide and NOx emissions poses many challenges, one of which is operating the engine within an operating window of air/fuel proportions that allows the catalyst components to perform optimally, reducing emissions to the maximum extent possible.
- the air/fuel proportion window is relatively narrow, thus hindering the ability to operate the engine at a richer burn that would reduce NOx emissions.
- a catalyst system may include a three-way catalyst that may receive exhaust gases from an engine and convert the exhaust gases to first converted exhaust gases.
- An ammonia slip catalyst may receive the first converted exhaust gases and convert the first converted exhaust gases to second converted exhaust gases.
- a hydrocarbon oxidation catalyst may receive the second converted exhaust gases and convert the second converted exhaust gases to third converted exhaust gases.
- a method for receiving exhaust gases from an engine at a three-way catalyst and converting the exhaust gases to first converted exhaust gases.
- An ammonia slip catalyst may receive the first converted exhaust gases and converting the first converted exhaust gases to second converted exhaust gases.
- a hydrocarbon oxidation catalyst may receive the second converted exhaust gases and convert the second converted exhaust gases to third converted exhaust gases.
- an engine may include an internal combustion component that generates exhaust gases.
- a three-way catalyst may receive the exhaust gases and convert the exhaust gases to first converted exhaust gases.
- An ammonia slip catalyst may receive the first converted exhaust gases and convert the first converted exhaust gases to second converted exhaust gases.
- a hydrocarbon oxidation catalyst may receive the second converted exhaust gases and convert the second converted exhaust gases to third converted exhaust gases.
- FIG. 1 is a block diagram of a non-limiting exemplary rich-burn engine and catalyst system.
- FIG. 2 is a block diagram of another non-limiting exemplary rich-burn engine and catalyst system.
- FIG. 3 is a block diagram of another non-limiting exemplary rich-burn engine and catalyst system.
- FIG. 4 is a flowchart illustrating a method of implementing a non-limiting exemplary rich-burn engine and catalyst system.
- FIG. 1 illustrates exemplary system 100 , including engine 110 and catalyst system 111 , that may be implemented according to an embodiment. Note that the entire system 100 may also be referred to as an “engine”.
- System 100 is a simplified block diagram that will be used to explain the concepts disclosed herein, and therefore is not to be construed as setting forth any physical requirements or particular configuration required for any embodiment disclosed herein. All components, devices, systems and methods described herein may be implemented with or take any shape, form, type, or number of components, and any combination of any such components that are capable of implementing the disclosed embodiments. All such embodiments are contemplated as within the scope of the present disclosure.
- Engine 110 may be any type of internal combustion engine or any device, component, system that includes an internal combustion component that generates exhaust gases.
- engine 110 may be a natural gas fueled internal combustion engine configured to operate with a stoichiometric amount of fuel or a slight excess of fuel in proportion to oxygen (i.e., rich).
- Catalyst system 111 may include catalyst components 120 , 130 , and 140 , with catalyst system midpoints 171 , 172 , and 173 , and exhaust point 174 .
- Catalyst system midpoints 171 , 172 , and 173 may be any pipe, connection, or any other component, or any section or subsection thereof, of system 100 that separates or is otherwise configured between two catalyst components (e.g., catalyst components 120 , 130 , and 140 ).
- Engine 110 may exhaust gases through catalyst system 111 in the direction indicated by exhaust flow 101 , i.e., from engine 110 through catalyst system midpoint 171 and into catalyst component 120 , from catalyst component 120 through catalyst system midpoint 172 and into catalyst component 130 , etc., until gases are ultimately exhausted at exhaust point 174 .
- Each of catalyst components 120 , 130 , and 140 may convert received exhaust gases to converted exhaust gases as described herein.
- engine 110 is a rich burn engine exhausting gases via catalyst system midpoint 171 into catalyst component 120 .
- catalyst component 120 may be a non-selective catalytic reduction (NSCR) subsystem, commonly referred to as a three-way catalyst. Where catalyst component 120 is a three-way catalyst, catalyst component 120 may reduce CO and hydrocarbon emissions using an oxidation process, while also reducing NOx emissions using a reduction process.
- NCR non-selective catalytic reduction
- Gases exhausted into catalyst component 120 by engine 110 may include NOx, carbon monoxide, and ammonia.
- Catalyst component 120 may convert some or all of the NOx that enters catalyst component 120 into one or more other compounds, such as methane and ammonia. These generated compounds may be converted to other compounds using additional catalyst system components, as described herein. While some exhaust components entering catalyst component 120 , such as carbon monoxide and ammonia, may be converted into other compounds by catalyst component 120 , at least some of these compounds may be not be converted to another compound by catalyst component 120 and may be exhausted from catalyst component 120 through catalyst system midpoint 172 and into catalyst component 130 .
- Catalyst component 130 may be an ammonia slip catalyst that may address ammonia that is emitted from catalyst component 120 unreacted.
- catalyst component 130 may be a dual layer catalyst with low precious metal loading and/or a zeolite coating.
- a dual layer catalyst may be configured with two catalysts, each performing different functions, coated or otherwise configured on the same substrate.
- catalyst component 130 may be an ammonia slip catalyst that has a precious metal loading and a zeolite coating on a same substrate.
- the precious metal loading used in catalyst component 130 may be a lower loading than a typical diesel oxidation catalyst and/or a typical three-way catalyst.
- Catalyst component 130 may oxidize the ammonia and carbon monoxide received from catalyst component 120 to dinitrogen (N 2 , commonly referred to as simply “nitrogen”) and carbon dioxide (CO 2 ), respectively.
- air may be added into the exhaust flow at catalyst system midpoint 172 before the exhaust enters catalyst component 130 by injecting air into the flow with mid-bed air injection component 150 . This added air may improve and/or assist in the oxidation processes performed at catalyst component 130 and/or catalyst component 140 .
- Mid-bed air injection component 150 may be any means, component, device, or combination thereof capable of introducing additional air into the exhaust stream, and all such embodiments are contemplated as within the scope of the present disclosure.
- catalyst component 130 may successfully convert the received ammonia and carbon monoxide to less toxic compounds, other compounds, some of which may be unburnt hydrocarbons exhausted from engine 110 , may be not be converted to another compound by catalyst component 130 and may be exhausted from catalyst component 130 through catalyst system midpoint 173 and into catalyst component 140 .
- methane may be included in the exhaust flow from catalyst component 130 to catalyst component 140 as a remnant of hydrocarbons not burnt by engine 110 .
- Catalyst component 140 may be a hydrocarbon oxidation catalyst that may address unburnt hydrocarbons and/or any other unreacted emissions that are emitted from catalyst component 130 .
- Catalyst component 140 may contain precious metals such as platinum (Pt) and palladium (Pd). In some embodiments, the ratio of Pd to Pt may be greater than one.
- catalyst component 140 may convert methane into carbon dioxide, as well as converting other hydrocarbons into less toxic compounds. The converted exhaust, at this point much less toxic, is exhausted from system 100 at exhaust point 174 .
- FIG. 2 illustrates exemplary system 200 , including engine 210 and catalyst system 211 , that may be implemented according to an embodiment. Note that the entire system 200 may also be referred to as an “engine”.
- System 200 is a simplified block diagram that will be used to explain the concepts disclosed herein, and therefore is not to be construed as setting forth any physical requirements or particular configuration required for any embodiment disclosed herein. All components, devices, systems and methods described herein may be implemented with or take any shape, form, type, or number of components, and any combination of any such components that are capable of implementing the disclosed embodiments. All such embodiments are contemplated as within the scope of the present disclosure.
- Engine 210 may be any type of internal combustion engine or any device, component, system that includes an internal combustion component that generates exhaust gases.
- engine 210 may be a natural gas fueled internal combustion engine configured to operate with a stoichiometric amount of fuel or a slight excess of fuel in proportion to oxygen (i.e., rich).
- Catalyst system 211 may include catalyst components 220 , 230 , and 240 , with catalyst system midpoints 271 , 272 , and 273 , and exhaust point 274 .
- Catalyst system midpoints 271 , 272 , and 273 may be any pipe, connection, or any other component, or any section or subsection thereof, of system 200 that separates or is otherwise configured between two catalyst components (e.g., catalyst components 220 , 230 , and 240 ).
- Engine 210 may exhaust gases through catalyst system 211 in the direction indicated by exhaust flow 201 , i.e., from engine 210 through catalyst system midpoint 271 and into catalyst component 220 , from catalyst component 220 through catalyst system midpoint 272 and into catalyst component 230 , etc., until gases are ultimately exhausted at exhaust point 274 .
- Each of catalyst components 220 , 230 , and 240 may convert received exhaust gases to converted exhaust gases as described herein.
- engine 210 is a rich burn engine exhausting gases via catalyst system midpoint 271 into catalyst component 220 .
- catalyst component 220 may be a three-way catalyst as described herein. Where catalyst component 220 is a three-way catalyst, catalyst component 220 may reduce CO and hydrocarbon emissions using an oxidation process, while also reducing NOx emissions using a reduction process.
- Gases exhausted into catalyst component 220 by engine 210 may include NOx, carbon monoxide, and ammonia.
- Catalyst component 220 may convert some or all of the NOx that enters catalyst component 220 into one or more other compounds, such as methane and ammonia. These generated compounds may be converted to other compounds using additional catalyst system components, as described herein. While some exhaust components entering catalyst component 220 , such as carbon monoxide and ammonia, may be converted into other compounds by catalyst component 220 , at least some of these compounds may be not be converted to another compound by catalyst component 220 and may be exhausted from catalyst component 220 through catalyst system midpoint 272 and into catalyst component 230 .
- Catalyst component 230 may be an ammonia slip catalyst that may address ammonia that is emitted from catalyst component 120 unreacted.
- catalyst component 230 may be a dual layer catalyst with low precious metal loading and a zeolite coating.
- a dual layer catalyst may be configured with two catalysts, each performing different functions, coated or otherwise configured on the same substrate.
- catalyst component 230 may be an ammonia slip catalyst that has a precious metal loading and a zeolite coating on a same substrate.
- the precious metal loading used in catalyst component 230 may be a lower loading than a typical diesel oxidation catalyst and/or a typical three-way catalyst.
- Catalyst component 230 may oxidize the ammonia and carbon monoxide received from catalyst component 220 to dinitrogen (N 2 , commonly referred to as simply “nitrogen”) and carbon dioxide (CO 2 ), respectively.
- N 2 dinitrogen
- CO 2 carbon dioxide
- catalyst component 230 may successfully convert the received ammonia and carbon monoxide to less toxic compounds, other compounds, some of which may be unburnt hydrocarbons exhausted from engine 210 , may be not be converted to another compound by catalyst component 230 and may be exhausted from catalyst component 230 through catalyst system midpoint 273 and into catalyst component 240 .
- methane may be included in the exhaust flow from catalyst component 230 to catalyst component 240 as a remnant of hydrocarbons not burnt by engine 210 .
- air may be added into the exhaust flow at catalyst system midpoint 273 before the exhaust enters catalyst component 240 by injecting air into the flow with mid-bed air injection component 260 . This added air may improve and/or assist in the oxidation processes performed at catalyst component 240 .
- Mid-bed air injection component 260 may be any means, component, device, or combination thereof capable of introducing additional air into the exhaust stream, and all such embodiments are contemplated as within the scope of the present disclosure.
- Catalyst component 240 may be a hydrocarbon oxidation catalyst that may address unburnt hydrocarbons and/or any other unreacted emissions that are emitted from catalyst component 230 .
- Catalyst component 240 may contain precious metals such as platinum (Pt) and palladium (Pd). In some embodiments, the ratio of Pd to Pt may be greater than one. In an embodiment may convert methane into carbon dioxide, as well as converting other hydrocarbons into less toxic compounds. The converted exhaust, at this point much less toxic, is exhausted from system 200 at exhaust point 274 .
- FIG. 3 illustrates exemplary system 300 , including engine 310 and catalyst system 311 , that may be implemented according to an embodiment. Note that the entirely of system 300 may also be referred to as an “engine”.
- System 300 is a simplified block diagram that will be used to explain the concepts disclosed herein, and therefore is not to be construed as setting forth any physical requirements or particular configuration required for any embodiment disclosed herein. All components, devices, systems and methods described herein may be implemented with or take any shape, form, type, or number of components, and any combination of any such components that are capable of implementing the disclosed embodiments. All such embodiments are contemplated as within the scope of the present disclosure.
- Engine 310 may be any type of internal combustion engine or any device, component, system that includes an internal combustion component that generates exhaust gases.
- engine 310 may be a natural gas fueled internal combustion engine configured to operate with a stoichiometric amount of fuel or a slight excess of fuel in proportion to oxygen (i.e., rich).
- Catalyst system 311 may include catalyst components 320 , 330 , and 340 , with catalyst system midpoints 371 , 372 , and 373 , and exhaust point 374 .
- Catalyst system midpoints 371 , 372 , and 373 may be any pipe, connection, or any other component, or any section or subsection thereof, of system 300 that separates or is otherwise configured between two catalyst components (e.g., catalyst components 320 , 330 , and 340 ).
- Engine 210 may exhaust gases through catalyst system 211 in the direction indicated by exhaust flow 301 , i.e., from engine 310 through catalyst system midpoint 371 and into catalyst component 320 , from catalyst component 320 through catalyst system midpoint 372 and into catalyst component 330 , etc., until gases are ultimately exhausted at exhaust point 374 .
- Each of catalyst components 320 , 330 , and 340 may convert received exhaust gases to converted exhaust gases as described herein.
- engine 310 is a rich burn engine exhausting gases via catalyst system midpoint 371 into catalyst component 320 .
- catalyst component 320 may be a three-way catalyst as described herein. Where catalyst component 320 is a three-way catalyst, catalyst component 220 may reduce CO and hydrocarbon emissions using an oxidation process, while also reducing NOx emissions using a reduction process.
- Gases exhausted into catalyst component 320 by engine 310 may include NOx, carbon monoxide, and ammonia.
- Catalyst component 320 may convert some or all of the NOx that enters catalyst component 320 into one or more other compounds, such as methane and ammonia. These generated compounds may be converted to other compounds using additional catalyst system components, as described herein. While some exhaust components entering catalyst component 320 , such as carbon monoxide and ammonia, may be converted into other compounds by catalyst component 320 , at least some of these compounds may be not be converted to another compound by catalyst component 320 and may be exhausted from catalyst component 320 through catalyst system midpoint 372 and into catalyst component 330 .
- Catalyst component 330 may be an ammonia slip catalyst that may address ammonia that is emitted from catalyst component 120 unreacted.
- catalyst component 330 may be a dual layer catalyst with low precious metal loading and a zeolite coating.
- a dual layer catalyst may be configured with two catalysts, each performing different functions, coated or otherwise configured on the same substrate.
- catalyst component 330 may be an ammonia slip catalyst that has a precious metal loading and a zeolite coating on a same substrate.
- the precious metal loading used in catalyst component 330 may be a lower loading than a typical diesel oxidation catalyst and/or a typical three-way catalyst.
- Catalyst component 330 may oxidize the ammonia and carbon monoxide received from catalyst component 320 to dinitrogen (N 2 , commonly referred to as simply “nitrogen”) and carbon dioxide (CO 2 ), respectively.
- air may be added into the exhaust flow at catalyst system midpoint 372 before the exhaust enters catalyst component 330 by injecting air into the flow with mid-bed air injection component 350 . This added air may improve and/or assist in the oxidation processes performed at catalyst component 330 and/or catalyst component 340 .
- Mid-bed air injection component 350 may be any means, component, device, or combination thereof capable of introducing additional air into the exhaust stream, and all such embodiments are contemplated as within the scope of the present disclosure.
- catalyst component 330 may successfully convert the received ammonia and carbon monoxide to less toxic compounds, other compounds, some of which may be unburnt hydrocarbons exhausted from engine 310 , may be not be converted to another compound by catalyst component 330 and may be exhausted from catalyst component 330 through catalyst system midpoint 373 and into catalyst component 340 .
- methane may be included in the exhaust flow from catalyst component 330 to catalyst component 340 as a remnant of hydrocarbons not burnt by engine 310 .
- more air may be added into the exhaust flow at catalyst system midpoint 373 before the exhaust enters catalyst component 340 by injecting air into the flow at a second point, in an embodiment with mid-bed air injection component 360 .
- Mid-bed air injection component 360 may be any means, component, device, or combination thereof capable of introducing additional air into the exhaust stream, and all such embodiments are contemplated as within the scope of the present disclosure.
- Catalyst component 340 may be a hydrocarbon oxidation catalyst that may address unburnt hydrocarbons and/or any other unreacted emissions that are emitted from catalyst component 330 .
- Catalyst component 340 may contain precious metals such as platinum (Pt) and palladium (Pd). In some embodiments, the ratio of Pd to Pt may be greater than one.
- catalyst component 140 may convert methane into carbon dioxide, as well as converting other hydrocarbons into less toxic compounds. The converted exhaust, at this point much less toxic, is exhausted from system 300 at exhaust point 374 .
- FIG. 4 illustrates exemplary, non-limiting method 400 of implementing an embodiment as disclosed herein.
- Method 400 and the individual actions and functions described in method 400 , may be performed by any one or more devices or components, including those described herein, such as the systems illustrated in FIGS. 1-3 .
- method 400 may be performed by any other devices, components, or combinations thereof, in some embodiments in conjunction with other systems, devices and/or components.
- any of the functions and/or actions described in regard to any of the blocks of method 400 may be performed in any order, in isolation, with a subset of other functions and/or actions described in regard to any of the other blocks of method 400 or any other method described herein, and in combination with other functions and/or actions, including those described herein and those not set forth herein. All such embodiments are contemplated as within the scope of the present disclosure.
- exhaust gases may be received at a catalyst system.
- components of the received exhaust gases may be converted to less toxic components using a three-way catalyst.
- NOx may be converted into one or more other compounds, such as methane and ammonia. While some exhaust components may be converted into other compounds at block 420 , at least some of received gases may be not be converted to another compound and may be exhausted to be converted by another catalyst component.
- air may be injected into the exhaust stream exhausted by the three-way catalyst performing conversion at block 420 , in an embodiment by a mid-bed air injection component.
- This added air may improve and/or assist in the oxidation processes performed at block 440 .
- the mid-bed air injection component may be any means, component, device, or combination thereof capable of introducing additional air into the exhaust stream, and all such embodiments are contemplated as within the scope of the present disclosure. Note that in some embodiments, no air may be injected at this point and the function of block 430 may be omitted.
- exhaust gasses may be received and converted at an ammonia slip catalyst.
- the ammonia slip catalyst may be a dual layer catalyst with low precious metal loading and/or a zeolite coating.
- the ammonia slip catalyst may oxidize ammonia and carbon monoxide received from the three-way catalyst into dinitrogen (N 2 , commonly referred to as simply “nitrogen”) and carbon dioxide (CO 2 ), respectively.
- air may be injected into the exhaust stream exhausted by the ammonia slip catalyst performing conversion at block 440 , in an embodiment by a mid-bed air injection component.
- This added air may improve and/or assist in the oxidation processes performed at block 460 .
- the mid-bed air injection component may be any means, component, device, or combination thereof capable of introducing additional air into the exhaust stream, and all such embodiments are contemplated as within the scope of the present disclosure. Note that in some embodiments, no air may be injected at this point and the function of block 450 may be omitted.
- Embodiments that include any number of mid-bed air injection components or functions, locating anywhere within a catalyst system, as well as embodiments that do not use any mid-bed air injection, are contemplated as within the scope of the present disclosure.
- exhaust gasses may be received and converted at hydrocarbon oxidation catalyst.
- the hydrocarbon oxidation catalyst may convert methane into carbon dioxide, and may convert other hydrocarbons into less toxic compounds.
- the converted exhaust gases, at this point much less toxic, are exhausted at block 470 .
- the technical effect of the systems and methods set forth herein is the ability to meet all emissions regulations using a single catalyst system with a rich-burn engine.
- the use of the disclosed processes and systems may reduce the emissions of such engines while enabling them to run richly in a wider operating window, and thereby exploit the advantages of rich-burn engines that were previously out of reach due to emissions standards.
- the disclosed catalyst systems and methods may be combined with other systems and technologies in order to achieve even greater emissions control and engine performance. All such embodiments are contemplated as within the scope of the present disclosure.
Abstract
A catalyst system may include a three-way catalyst that may receive exhaust gases from an engine and convert the exhaust gases to first converted exhaust gases. An ammonia slip catalyst may receive the first converted exhaust gases and convert the first converted exhaust gases to second converted exhaust gases. A hydrocarbon oxidation catalyst may receive the second converted exhaust gases and convert the second converted exhaust gases to third converted exhaust gases.
Description
- This application is a continuation of patent application Ser. No. 13/833,528, entitled “Aftertreatment System for Simultaneous Emissions Control in Stationary Rich Burn Engines,” filed Mar. 15, 2013, which is herein incorporated by reference in its entirety for all purposes.
- The present disclosure relates to emissions controls for internal combustion engines generally and in particular to methods and systems for simultaneous emissions control in stationary rich burn engines.
- Internal combustion engines are ideally operated in a way that the combustion mixture contains air and fuel in the exact relative proportions required for a stoichiometric combustion reaction (i.e., where the fuel is burned completely.) A rich-burn engine may operate with a stoichiometric amount of fuel or a slight excess of fuel, while a lean-burn engine operates with an excess of oxygen (O2) compared to the amount required for stoichiometric combustion. The operation of an internal combustion engine in lean mode may reduce throttling losses and may take advantage of higher compression ratios thereby providing improvements in performance and efficiency. Rich burn engines have the benefits of being relatively simple, reliable, stable, and adapt well to changing loads. Rich burn engines may also have lower nitrogen oxide emissions, but at the expense of increased emissions of other compounds.
- In order to comply with emissions standards, many rich burn internal combustion engines utilize catalysts, such as non-selective catalytic reduction (NSCR) subsystems (commonly known as three-way catalysts). Catalysts may reduce emissions of the nitrogen oxides NO and NO2 (collectively NOx), carbon monoxide (CO), ammonia (NH3), methane (CH4), other volatile organic compounds (VOC), and other compounds and emissions components by converting such emissions components to less toxic substances. This conversion is performed in a catalyst component using catalyzed chemical reactions. Catalysts can have high reduction efficiencies and can provide an economical means of meeting emissions standards (often expressed in terms of grams of emissions per brake horsepower hour (g/bhp-hr)). Separate catalyst components or devices may be included in the exhaust pathway of a rich burn engine to convert different emissions components. For example, one catalyst component may convert carbon monoxide and NOx while another may convert ammonia and methane.
- In the oxidation process, the resulting substances generated by a catalyst component may require further conversion by a subsequent catalyst. For example, a catalyst component may convert carbon monoxide and NOx generated by an engine into ammonia, which may then be converted by another catalyst component. In a rich burn engine, controlling carbon monoxide and NOx emissions poses many challenges, one of which is operating the engine within an operating window of air/fuel proportions that allows the catalyst components to perform optimally, reducing emissions to the maximum extent possible. The air/fuel proportion window is relatively narrow, thus hindering the ability to operate the engine at a richer burn that would reduce NOx emissions.
- In an exemplary non-limiting embodiment, a catalyst system may include a three-way catalyst that may receive exhaust gases from an engine and convert the exhaust gases to first converted exhaust gases. An ammonia slip catalyst may receive the first converted exhaust gases and convert the first converted exhaust gases to second converted exhaust gases. A hydrocarbon oxidation catalyst may receive the second converted exhaust gases and convert the second converted exhaust gases to third converted exhaust gases.
- In another exemplary non-limiting embodiment, a method is disclosed for receiving exhaust gases from an engine at a three-way catalyst and converting the exhaust gases to first converted exhaust gases. An ammonia slip catalyst may receive the first converted exhaust gases and converting the first converted exhaust gases to second converted exhaust gases. A hydrocarbon oxidation catalyst may receive the second converted exhaust gases and convert the second converted exhaust gases to third converted exhaust gases.
- In another exemplary non-limiting embodiment, an engine may include an internal combustion component that generates exhaust gases. A three-way catalyst may receive the exhaust gases and convert the exhaust gases to first converted exhaust gases. An ammonia slip catalyst may receive the first converted exhaust gases and convert the first converted exhaust gases to second converted exhaust gases. A hydrocarbon oxidation catalyst may receive the second converted exhaust gases and convert the second converted exhaust gases to third converted exhaust gases.
- The foregoing summary, as well as the following detailed description, is better understood when read in conjunction with the drawings. For the purpose of illustrating the claimed subject matter, there is shown in the drawings examples that illustrate various embodiments; however, the invention is not limited to the specific systems and methods disclosed.
- These and other features, aspects, and advantages of the present subject matter will become better understood when the following detailed description is read with reference to the accompanying drawings, wherein:
-
FIG. 1 is a block diagram of a non-limiting exemplary rich-burn engine and catalyst system. -
FIG. 2 is a block diagram of another non-limiting exemplary rich-burn engine and catalyst system. -
FIG. 3 is a block diagram of another non-limiting exemplary rich-burn engine and catalyst system. -
FIG. 4 is a flowchart illustrating a method of implementing a non-limiting exemplary rich-burn engine and catalyst system. -
FIG. 1 illustratesexemplary system 100, includingengine 110 andcatalyst system 111, that may be implemented according to an embodiment. Note that theentire system 100 may also be referred to as an “engine”.System 100 is a simplified block diagram that will be used to explain the concepts disclosed herein, and therefore is not to be construed as setting forth any physical requirements or particular configuration required for any embodiment disclosed herein. All components, devices, systems and methods described herein may be implemented with or take any shape, form, type, or number of components, and any combination of any such components that are capable of implementing the disclosed embodiments. All such embodiments are contemplated as within the scope of the present disclosure. -
Engine 110 may be any type of internal combustion engine or any device, component, system that includes an internal combustion component that generates exhaust gases. In an embodiment,engine 110 may be a natural gas fueled internal combustion engine configured to operate with a stoichiometric amount of fuel or a slight excess of fuel in proportion to oxygen (i.e., rich).Catalyst system 111 may includecatalyst components catalyst system midpoints exhaust point 174.Catalyst system midpoints system 100 that separates or is otherwise configured between two catalyst components (e.g.,catalyst components Engine 110 may exhaust gases throughcatalyst system 111 in the direction indicated by exhaust flow 101, i.e., fromengine 110 through catalyst system midpoint 171 and intocatalyst component 120, fromcatalyst component 120 throughcatalyst system midpoint 172 and intocatalyst component 130, etc., until gases are ultimately exhausted atexhaust point 174. Each ofcatalyst components - In an embodiment,
engine 110 is a rich burn engine exhausting gases via catalyst system midpoint 171 intocatalyst component 120. In this embodiment,catalyst component 120 may be a non-selective catalytic reduction (NSCR) subsystem, commonly referred to as a three-way catalyst. Wherecatalyst component 120 is a three-way catalyst,catalyst component 120 may reduce CO and hydrocarbon emissions using an oxidation process, while also reducing NOx emissions using a reduction process. - Gases exhausted into
catalyst component 120 byengine 110 may include NOx, carbon monoxide, and ammonia.Catalyst component 120 may convert some or all of the NOx that enterscatalyst component 120 into one or more other compounds, such as methane and ammonia. These generated compounds may be converted to other compounds using additional catalyst system components, as described herein. While some exhaust components enteringcatalyst component 120, such as carbon monoxide and ammonia, may be converted into other compounds bycatalyst component 120, at least some of these compounds may be not be converted to another compound bycatalyst component 120 and may be exhausted fromcatalyst component 120 throughcatalyst system midpoint 172 and intocatalyst component 130. -
Catalyst component 130 may be an ammonia slip catalyst that may address ammonia that is emitted fromcatalyst component 120 unreacted. In an embodiment,catalyst component 130 may be a dual layer catalyst with low precious metal loading and/or a zeolite coating. In such embodiments, a dual layer catalyst may be configured with two catalysts, each performing different functions, coated or otherwise configured on the same substrate. For example, in anembodiment catalyst component 130 may be an ammonia slip catalyst that has a precious metal loading and a zeolite coating on a same substrate. The precious metal loading used incatalyst component 130 may be a lower loading than a typical diesel oxidation catalyst and/or a typical three-way catalyst.Catalyst component 130 may oxidize the ammonia and carbon monoxide received fromcatalyst component 120 to dinitrogen (N2, commonly referred to as simply “nitrogen”) and carbon dioxide (CO2), respectively. In an embodiment, air may be added into the exhaust flow atcatalyst system midpoint 172 before the exhaust enterscatalyst component 130 by injecting air into the flow with mid-bedair injection component 150. This added air may improve and/or assist in the oxidation processes performed atcatalyst component 130 and/orcatalyst component 140. Mid-bedair injection component 150 may be any means, component, device, or combination thereof capable of introducing additional air into the exhaust stream, and all such embodiments are contemplated as within the scope of the present disclosure. - While
catalyst component 130 may successfully convert the received ammonia and carbon monoxide to less toxic compounds, other compounds, some of which may be unburnt hydrocarbons exhausted fromengine 110, may be not be converted to another compound bycatalyst component 130 and may be exhausted fromcatalyst component 130 throughcatalyst system midpoint 173 and intocatalyst component 140. In some embodiments, methane may be included in the exhaust flow fromcatalyst component 130 tocatalyst component 140 as a remnant of hydrocarbons not burnt byengine 110. -
Catalyst component 140 may be a hydrocarbon oxidation catalyst that may address unburnt hydrocarbons and/or any other unreacted emissions that are emitted fromcatalyst component 130.Catalyst component 140 may contain precious metals such as platinum (Pt) and palladium (Pd). In some embodiments, the ratio of Pd to Pt may be greater than one. In an embodiment,catalyst component 140 may convert methane into carbon dioxide, as well as converting other hydrocarbons into less toxic compounds. The converted exhaust, at this point much less toxic, is exhausted fromsystem 100 atexhaust point 174. -
FIG. 2 illustratesexemplary system 200, includingengine 210 andcatalyst system 211, that may be implemented according to an embodiment. Note that theentire system 200 may also be referred to as an “engine”.System 200 is a simplified block diagram that will be used to explain the concepts disclosed herein, and therefore is not to be construed as setting forth any physical requirements or particular configuration required for any embodiment disclosed herein. All components, devices, systems and methods described herein may be implemented with or take any shape, form, type, or number of components, and any combination of any such components that are capable of implementing the disclosed embodiments. All such embodiments are contemplated as within the scope of the present disclosure. -
Engine 210 may be any type of internal combustion engine or any device, component, system that includes an internal combustion component that generates exhaust gases. In an embodiment,engine 210 may be a natural gas fueled internal combustion engine configured to operate with a stoichiometric amount of fuel or a slight excess of fuel in proportion to oxygen (i.e., rich).Catalyst system 211 may includecatalyst components exhaust point 274. Catalyst system midpoints 271, 272, and 273 may be any pipe, connection, or any other component, or any section or subsection thereof, ofsystem 200 that separates or is otherwise configured between two catalyst components (e.g.,catalyst components Engine 210 may exhaust gases throughcatalyst system 211 in the direction indicated by exhaust flow 201, i.e., fromengine 210 throughcatalyst system midpoint 271 and intocatalyst component 220, fromcatalyst component 220 throughcatalyst system midpoint 272 and intocatalyst component 230, etc., until gases are ultimately exhausted atexhaust point 274. Each ofcatalyst components - In an embodiment,
engine 210 is a rich burn engine exhausting gases viacatalyst system midpoint 271 intocatalyst component 220. In this embodiment,catalyst component 220 may be a three-way catalyst as described herein. Wherecatalyst component 220 is a three-way catalyst,catalyst component 220 may reduce CO and hydrocarbon emissions using an oxidation process, while also reducing NOx emissions using a reduction process. - Gases exhausted into
catalyst component 220 byengine 210 may include NOx, carbon monoxide, and ammonia.Catalyst component 220 may convert some or all of the NOx that enterscatalyst component 220 into one or more other compounds, such as methane and ammonia. These generated compounds may be converted to other compounds using additional catalyst system components, as described herein. While some exhaust components enteringcatalyst component 220, such as carbon monoxide and ammonia, may be converted into other compounds bycatalyst component 220, at least some of these compounds may be not be converted to another compound bycatalyst component 220 and may be exhausted fromcatalyst component 220 throughcatalyst system midpoint 272 and intocatalyst component 230. -
Catalyst component 230 may be an ammonia slip catalyst that may address ammonia that is emitted fromcatalyst component 120 unreacted. In an embodiment,catalyst component 230 may be a dual layer catalyst with low precious metal loading and a zeolite coating. In such embodiments, a dual layer catalyst may be configured with two catalysts, each performing different functions, coated or otherwise configured on the same substrate. For example, in anembodiment catalyst component 230 may be an ammonia slip catalyst that has a precious metal loading and a zeolite coating on a same substrate. The precious metal loading used incatalyst component 230 may be a lower loading than a typical diesel oxidation catalyst and/or a typical three-way catalyst.Catalyst component 230 may oxidize the ammonia and carbon monoxide received fromcatalyst component 220 to dinitrogen (N2, commonly referred to as simply “nitrogen”) and carbon dioxide (CO2), respectively. - While
catalyst component 230 may successfully convert the received ammonia and carbon monoxide to less toxic compounds, other compounds, some of which may be unburnt hydrocarbons exhausted fromengine 210, may be not be converted to another compound bycatalyst component 230 and may be exhausted fromcatalyst component 230 throughcatalyst system midpoint 273 and intocatalyst component 240. In some embodiments, methane may be included in the exhaust flow fromcatalyst component 230 tocatalyst component 240 as a remnant of hydrocarbons not burnt byengine 210. In an embodiment, air may be added into the exhaust flow atcatalyst system midpoint 273 before the exhaust enterscatalyst component 240 by injecting air into the flow with mid-bedair injection component 260. This added air may improve and/or assist in the oxidation processes performed atcatalyst component 240. Mid-bedair injection component 260 may be any means, component, device, or combination thereof capable of introducing additional air into the exhaust stream, and all such embodiments are contemplated as within the scope of the present disclosure. -
Catalyst component 240 may be a hydrocarbon oxidation catalyst that may address unburnt hydrocarbons and/or any other unreacted emissions that are emitted fromcatalyst component 230.Catalyst component 240 may contain precious metals such as platinum (Pt) and palladium (Pd). In some embodiments, the ratio of Pd to Pt may be greater than one. In an embodiment may convert methane into carbon dioxide, as well as converting other hydrocarbons into less toxic compounds. The converted exhaust, at this point much less toxic, is exhausted fromsystem 200 atexhaust point 274. -
FIG. 3 illustratesexemplary system 300, includingengine 310 andcatalyst system 311, that may be implemented according to an embodiment. Note that the entirely ofsystem 300 may also be referred to as an “engine”.System 300 is a simplified block diagram that will be used to explain the concepts disclosed herein, and therefore is not to be construed as setting forth any physical requirements or particular configuration required for any embodiment disclosed herein. All components, devices, systems and methods described herein may be implemented with or take any shape, form, type, or number of components, and any combination of any such components that are capable of implementing the disclosed embodiments. All such embodiments are contemplated as within the scope of the present disclosure. -
Engine 310 may be any type of internal combustion engine or any device, component, system that includes an internal combustion component that generates exhaust gases. In an embodiment,engine 310 may be a natural gas fueled internal combustion engine configured to operate with a stoichiometric amount of fuel or a slight excess of fuel in proportion to oxygen (i.e., rich).Catalyst system 311 may includecatalyst components exhaust point 374. Catalyst system midpoints 371, 372, and 373 may be any pipe, connection, or any other component, or any section or subsection thereof, ofsystem 300 that separates or is otherwise configured between two catalyst components (e.g.,catalyst components Engine 210 may exhaust gases throughcatalyst system 211 in the direction indicated by exhaust flow 301, i.e., fromengine 310 throughcatalyst system midpoint 371 and intocatalyst component 320, fromcatalyst component 320 throughcatalyst system midpoint 372 and intocatalyst component 330, etc., until gases are ultimately exhausted atexhaust point 374. Each ofcatalyst components - In an embodiment,
engine 310 is a rich burn engine exhausting gases viacatalyst system midpoint 371 intocatalyst component 320. In this embodiment,catalyst component 320 may be a three-way catalyst as described herein. Wherecatalyst component 320 is a three-way catalyst,catalyst component 220 may reduce CO and hydrocarbon emissions using an oxidation process, while also reducing NOx emissions using a reduction process. - Gases exhausted into
catalyst component 320 byengine 310 may include NOx, carbon monoxide, and ammonia.Catalyst component 320 may convert some or all of the NOx that enterscatalyst component 320 into one or more other compounds, such as methane and ammonia. These generated compounds may be converted to other compounds using additional catalyst system components, as described herein. While some exhaust components enteringcatalyst component 320, such as carbon monoxide and ammonia, may be converted into other compounds bycatalyst component 320, at least some of these compounds may be not be converted to another compound bycatalyst component 320 and may be exhausted fromcatalyst component 320 throughcatalyst system midpoint 372 and intocatalyst component 330. -
Catalyst component 330 may be an ammonia slip catalyst that may address ammonia that is emitted fromcatalyst component 120 unreacted. In an embodiment,catalyst component 330 may be a dual layer catalyst with low precious metal loading and a zeolite coating. In such embodiments, a dual layer catalyst may be configured with two catalysts, each performing different functions, coated or otherwise configured on the same substrate. For example, in anembodiment catalyst component 330 may be an ammonia slip catalyst that has a precious metal loading and a zeolite coating on a same substrate. The precious metal loading used incatalyst component 330 may be a lower loading than a typical diesel oxidation catalyst and/or a typical three-way catalyst.Catalyst component 330 may oxidize the ammonia and carbon monoxide received fromcatalyst component 320 to dinitrogen (N2, commonly referred to as simply “nitrogen”) and carbon dioxide (CO2), respectively. In this embodiment, air may be added into the exhaust flow atcatalyst system midpoint 372 before the exhaust enterscatalyst component 330 by injecting air into the flow with mid-bedair injection component 350. This added air may improve and/or assist in the oxidation processes performed atcatalyst component 330 and/orcatalyst component 340. Mid-bedair injection component 350 may be any means, component, device, or combination thereof capable of introducing additional air into the exhaust stream, and all such embodiments are contemplated as within the scope of the present disclosure. - While
catalyst component 330 may successfully convert the received ammonia and carbon monoxide to less toxic compounds, other compounds, some of which may be unburnt hydrocarbons exhausted fromengine 310, may be not be converted to another compound bycatalyst component 330 and may be exhausted fromcatalyst component 330 throughcatalyst system midpoint 373 and intocatalyst component 340. In some embodiments, methane may be included in the exhaust flow fromcatalyst component 330 tocatalyst component 340 as a remnant of hydrocarbons not burnt byengine 310. In this embodiment, more air may be added into the exhaust flow atcatalyst system midpoint 373 before the exhaust enterscatalyst component 340 by injecting air into the flow at a second point, in an embodiment with mid-bedair injection component 360. This added air may improve and/or assist in the oxidation processes performed atcatalyst component 340. Mid-bedair injection component 360 may be any means, component, device, or combination thereof capable of introducing additional air into the exhaust stream, and all such embodiments are contemplated as within the scope of the present disclosure. -
Catalyst component 340 may be a hydrocarbon oxidation catalyst that may address unburnt hydrocarbons and/or any other unreacted emissions that are emitted fromcatalyst component 330.Catalyst component 340 may contain precious metals such as platinum (Pt) and palladium (Pd). In some embodiments, the ratio of Pd to Pt may be greater than one. In an embodiment,catalyst component 140 may convert methane into carbon dioxide, as well as converting other hydrocarbons into less toxic compounds. The converted exhaust, at this point much less toxic, is exhausted fromsystem 300 atexhaust point 374. -
FIG. 4 illustrates exemplary,non-limiting method 400 of implementing an embodiment as disclosed herein.Method 400, and the individual actions and functions described inmethod 400, may be performed by any one or more devices or components, including those described herein, such as the systems illustrated inFIGS. 1-3 . In an embodiment,method 400 may be performed by any other devices, components, or combinations thereof, in some embodiments in conjunction with other systems, devices and/or components. Note that any of the functions and/or actions described in regard to any of the blocks ofmethod 400 may be performed in any order, in isolation, with a subset of other functions and/or actions described in regard to any of the other blocks ofmethod 400 or any other method described herein, and in combination with other functions and/or actions, including those described herein and those not set forth herein. All such embodiments are contemplated as within the scope of the present disclosure. - At
block 410, exhaust gases may be received at a catalyst system. Atblock 420, components of the received exhaust gases may be converted to less toxic components using a three-way catalyst. For example, NOx may be converted into one or more other compounds, such as methane and ammonia. While some exhaust components may be converted into other compounds atblock 420, at least some of received gases may be not be converted to another compound and may be exhausted to be converted by another catalyst component. - At
block 430, air may be injected into the exhaust stream exhausted by the three-way catalyst performing conversion atblock 420, in an embodiment by a mid-bed air injection component. This added air may improve and/or assist in the oxidation processes performed atblock 440. The mid-bed air injection component may be any means, component, device, or combination thereof capable of introducing additional air into the exhaust stream, and all such embodiments are contemplated as within the scope of the present disclosure. Note that in some embodiments, no air may be injected at this point and the function ofblock 430 may be omitted. - At
block 440 exhaust gasses may be received and converted at an ammonia slip catalyst. The ammonia slip catalyst may be a dual layer catalyst with low precious metal loading and/or a zeolite coating. The ammonia slip catalyst may oxidize ammonia and carbon monoxide received from the three-way catalyst into dinitrogen (N2, commonly referred to as simply “nitrogen”) and carbon dioxide (CO2), respectively. - At
block 450, air may be injected into the exhaust stream exhausted by the ammonia slip catalyst performing conversion atblock 440, in an embodiment by a mid-bed air injection component. This added air may improve and/or assist in the oxidation processes performed atblock 460. The mid-bed air injection component may be any means, component, device, or combination thereof capable of introducing additional air into the exhaust stream, and all such embodiments are contemplated as within the scope of the present disclosure. Note that in some embodiments, no air may be injected at this point and the function ofblock 450 may be omitted. Embodiments that include any number of mid-bed air injection components or functions, locating anywhere within a catalyst system, as well as embodiments that do not use any mid-bed air injection, are contemplated as within the scope of the present disclosure. - At
block 460 exhaust gasses may be received and converted at hydrocarbon oxidation catalyst. The hydrocarbon oxidation catalyst may convert methane into carbon dioxide, and may convert other hydrocarbons into less toxic compounds. The converted exhaust gases, at this point much less toxic, are exhausted atblock 470. - The technical effect of the systems and methods set forth herein is the ability to meet all emissions regulations using a single catalyst system with a rich-burn engine. As will be appreciated by those skilled in the art, the use of the disclosed processes and systems may reduce the emissions of such engines while enabling them to run richly in a wider operating window, and thereby exploit the advantages of rich-burn engines that were previously out of reach due to emissions standards. Those skilled in the art will recognize that the disclosed catalyst systems and methods may be combined with other systems and technologies in order to achieve even greater emissions control and engine performance. All such embodiments are contemplated as within the scope of the present disclosure.
- This written description uses examples to disclose the subject matter contained herein, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of this disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
Claims (20)
1. A system comprising:
an exhaust aftertreament system, comprising:
a three-way catalyst that receives exhaust gases from an engine and converts the exhaust gases to first converted exhaust gases;
an ammonia slip catalyst that receives the first converted exhaust gases and converts the first converted exhaust gases to second converted exhaust gases;
a hydrocarbon oxidation catalyst that receives the second converted exhaust gases and converts the second converted exhaust gases to third converted exhaust gases; and
a mid-bed air injection system that injects air into the first converted exhaust gases upstream of the ammonia slip catalyst and injects air into the second converted exhaust gases upstream of the hydrocarbon oxidation catalyst.
2. The system of claim 1 , wherein the ammonia slip catalyst comprises a precious metal loading and a zeolite coating.
3. The system of claim 2 , wherein the precious metal loading comprises at least one of platinum or palladium.
4. The system of claim 1 , wherein the ammonia slip catalyst converts carbon monoxide in the first converted exhaust gases to carbon dioxide.
5. The system of claim 4 , wherein the ammonia slip catalyst converts ammonia in the first converted exhaust gases to nitrogen.
6. The system of claim 1 , comprising the engine coupled to the exhaust aftertreatment system.
7. The system of claim 6 , wherein the engine comprises a rich burn internal combustion engine.
8. A method comprising:
receiving exhaust gases from an engine at a three-way catalyst;
converting, at the three-way catalyst, the exhaust gases to first converted exhaust gases;
injecting air, via a mid-bed air injection system, into the first converted exhaust gases upstream of an ammonia slip catalyst;
receiving the first converted exhaust gases at the ammonia slip catalyst;
converting, at the ammonia slip catalyst, the first converted exhaust gases to second converted exhaust gases;
injecting air, via the mid-bed air injection system, into the second converted exhaust gases upstream of the hydrocarbon oxidation catalyst;
receiving the second converted exhaust gases at the hydrocarbon oxidation catalyst; and
converting, at the hydrocarbon oxidation catalyst, the second converted exhaust gases to third converted exhaust gases.
9. The method of claim 8 , wherein the ammonia slip catalyst comprises a precious metal loading and a zeolite coating.
10. The method of claim 9 , wherein the precious metal loading comprises at least one of platinum or palladium.
11. The method of claim 8 , wherein converting, at the ammonia slip catalyst, the first converted exhaust gases to the second converted exhaust gases comprises converting carbon monoxide in the first converted exhaust gases to carbon dioxide.
12. The method of claim 8 , wherein converting, at the ammonia slip catalyst, the first converted exhaust gases to the second converted exhaust gases comprises converting ammonia in the first converted exhaust gases to nitrogen.
13. The method of claim 8 , wherein the engine comprises a rich burn internal combustion engine.
14. A system comprising:
an internal combustion engine that generates exhaust gases;
a three-way catalyst that receives the exhaust gases and converts the exhaust gases to first converted exhaust gases;
an ammonia slip catalyst that receives the first converted exhaust gases and converts the first converted exhaust gases to second converted exhaust gases;
a hydrocarbon oxidation catalyst that receives the second converted exhaust gases and converts the second converted exhaust gases to third converted exhaust gases; and
a mid-bed air injection system that injects air into the first converted exhaust gases upstream of the ammonia slip catalyst and injects air into the second converted exhaust gases upstream of the hydrocarbon oxidation catalyst.
15. The system of claim 14 , wherein the ammonia slip catalyst comprises a dual layer catalyst.
16. The system of claim 15 , wherein the ammonia slip catalyst comprises a precious metal loading and a zeolite coating.
17. The system of claim 14 , wherein the ammonia slip catalyst converts ammonia in the first converted exhaust gases to nitrogen.
18. The system of claim 14 , wherein the ammonia slip catalyst converts carbon monoxide in the first converted exhaust gases to carbon dioxide.
19. The system of claim 14 , wherein the internal combustion engine comprises a rich burn internal combustion engine.
20. The system of claim 14 , wherein the three-way catalyst comprises a first precious metal loading and the ammonia slip catalyst comprises a second precious metal loading, and the second precious metal loading is less than the first precious metal loading.
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DE19816276C2 (en) | 1998-04-11 | 2000-05-18 | Audi Ag | Method and device for operating an internal combustion engine |
DE10104160B4 (en) | 2001-01-30 | 2008-07-10 | Umicore Ag & Co. Kg | Method for operating an exhaust gas purification system for an internal combustion engine |
US6823663B2 (en) | 2002-11-21 | 2004-11-30 | Ford Global Technologies, Llc | Exhaust gas aftertreatment systems |
DE10300298A1 (en) * | 2003-01-02 | 2004-07-15 | Daimlerchrysler Ag | Exhaust gas aftertreatment device and method |
US20080072578A1 (en) * | 2006-09-21 | 2008-03-27 | Kumar Sanath V | Treatment Systems and Methods for Internal Combustion Engine Exhaust Streams |
US8776498B2 (en) * | 2008-04-16 | 2014-07-15 | Ford Global Technologies, Llc | Air-injection system to improve effectiveness of selective catalytic reduction catalyst for gasoline engines |
JP2010101310A (en) * | 2008-09-26 | 2010-05-06 | Yamaha Motor Co Ltd | Saddle-riding type vehicle |
CN105749747A (en) | 2009-04-17 | 2016-07-13 | 约翰逊马西有限公司 | Small pore molecular sieve supported copper catalysts |
US8621845B2 (en) * | 2011-08-17 | 2014-01-07 | GM Global Technology Operations LLC | Passive SCR control system and method |
US8505282B2 (en) * | 2011-09-09 | 2013-08-13 | GM Global Technology Operations LLC | Selective catalytic reduction (SCR) device control system |
US8661790B2 (en) * | 2011-11-07 | 2014-03-04 | GM Global Technology Operations LLC | Electronically heated NOx adsorber catalyst |
GB201200781D0 (en) * | 2011-12-12 | 2012-02-29 | Johnson Matthey Plc | Exhaust system for a lean-burn ic engine comprising a pgm component and a scr catalyst |
US9138686B2 (en) * | 2012-03-30 | 2015-09-22 | GM Global Technology Operations LLC | Carbon monoxide-selective oxidation catalysts |
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2013
- 2013-03-15 US US13/833,528 patent/US9114363B2/en not_active Expired - Fee Related
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2014
- 2014-03-06 CA CA 2844963 patent/CA2844963A1/en not_active Abandoned
- 2014-03-07 JP JP2014044486A patent/JP2014224525A/en active Pending
- 2014-03-11 BR BR102014005531A patent/BR102014005531A2/en not_active Application Discontinuation
- 2014-03-12 EP EP14159279.0A patent/EP2778363B1/en not_active Not-in-force
- 2014-03-12 KR KR20140028664A patent/KR20140113407A/en not_active Application Discontinuation
- 2014-03-17 CN CN201410096788.0A patent/CN104047682A/en active Pending
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2015
- 2015-07-14 US US14/798,723 patent/US20150315944A1/en not_active Abandoned
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
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US20180015446A1 (en) * | 2016-07-12 | 2018-01-18 | Johnson Matthey Public Limited Company | Oxidation catalyst for a stoichiometric natural gas engine |
US10807079B2 (en) * | 2016-07-12 | 2020-10-20 | Johnson Matthey Public Limited Company | Oxidation catalyst for a stoichiometric natural gas engine |
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BR102014005531A2 (en) | 2016-03-15 |
US20140260213A1 (en) | 2014-09-18 |
EP2778363B1 (en) | 2016-08-31 |
CN104047682A (en) | 2014-09-17 |
CA2844963A1 (en) | 2014-09-15 |
EP2778363A1 (en) | 2014-09-17 |
US9114363B2 (en) | 2015-08-25 |
KR20140113407A (en) | 2014-09-24 |
JP2014224525A (en) | 2014-12-04 |
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