WO1995004211A1 - PROCEDE DE REDUCTION DES EMISSIONS DE NOx DE MOTEURS DIESEL - Google Patents

PROCEDE DE REDUCTION DES EMISSIONS DE NOx DE MOTEURS DIESEL Download PDF

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Publication number
WO1995004211A1
WO1995004211A1 PCT/US1994/008582 US9408582W WO9504211A1 WO 1995004211 A1 WO1995004211 A1 WO 1995004211A1 US 9408582 W US9408582 W US 9408582W WO 9504211 A1 WO9504211 A1 WO 9504211A1
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WO
WIPO (PCT)
Prior art keywords
urea
ammonium
ammonia
combustion gases
reducing composition
Prior art date
Application number
PCT/US1994/008582
Other languages
English (en)
Inventor
Jeremy D. Peter-Hoblyn
Original Assignee
Platinum Plus, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Platinum Plus, Inc. filed Critical Platinum Plus, Inc.
Priority to AU74082/94A priority Critical patent/AU7408294A/en
Publication of WO1995004211A1 publication Critical patent/WO1995004211A1/fr

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation 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
    • B01D53/34Chemical or biological purification of waste gases
    • B01D53/92Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9404Removing only nitrogen compounds
    • B01D53/9409Nitrogen oxides
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust 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
    • F01N3/18Exhaust 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
    • F01N3/20Exhaust 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
    • F01N3/206Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00Adding substances to exhaust gases
    • F01N2610/02Adding substances to exhaust gases the substance being ammonia or urea
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02BINTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00Engines characterised by air compression and subsequent fuel addition
    • F02B3/06Engines characterised by air compression and subsequent fuel addition with compression ignition
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/10Internal combustion engine [ICE] based vehicles
    • Y02T10/12Improving ICE efficiencies

Definitions

  • the problems of controlling these pollutants are compounded because there is a trade-off between particulates and nitro ⁇ gen oxides — when the combustion conditions are modified to favor low nitrogen oxides emissions, particulates are in ⁇ creased.
  • Particulate traps offer advantages because NO x - reduction techniques, such as timing changes and exhaust gas recirculation, impose a trade-off with particulates. How ⁇ ever, particulate traps can decrease fuel economy and tend to increase the production of carbon monoxide. And, un ⁇ burned hydrocarbons remain a problem.
  • Diesel particulates and NO x are at the center of much concern and controversy. Both are associated with environmental problems, but to date no effective technique is commercially available to control both. Their chemistry and environmental impact present com ⁇ plex issues.
  • Diesel particulate matter is principally solid parti ⁇ cles of carbon with adsorbed hydrocarbons, sulfates and aqueous species.
  • adsorbed species include aldehydes and polycyclic aromatic hydrocarbons (also called PAH's). Some of these organics have been reported to be potential carcinogens or mutagens.
  • Unburned hydrocarbons include aldehydes, such as formaldehyde and acrolein, and are relat ⁇ ed to the characteristic diesel odor.
  • the aldehydes like carbon monoxide, are products of incomplete combustion.
  • N0 X principally NO and N0 2 , contributes to smog, ground level ozone formation and acid rain. NO is produced in large quantities at the high combustion temperatures associated with diesel engines.
  • the N0 2 is formed princi- pally by the post oxidation of NO in the diesel exhaust stream.
  • the present invention relates to a method for improving the operation of a diesel engine with reduced emissions of particulates and NO x .
  • the method comprises: (a) combusting a diesel fuel in a diesel engine under conditions favoring the production of low levels of particulates and resulting in the production of diesel combustion gases containing NO x ; (b) contacting the combustion gases in the cylinders with a NO x -reducing composition at a temperature effective to reduce the level of NO x in the combustion gases and produce ammonia or other active unoxidized byproduct (e.g., a free radical selected from the group consisting of NH ⁇ , NH 2 ⁇ , HNCO-, and combinations) by the decomposition of the NO x - reducing composition; and (c) passing the combustion gases through a catalyst to reduce NO x and ammonia or other active byproduct produced by decomposition of the NO x -reducing composition.
  • a NO x -reducing composition e.g., a free radical selected from the group
  • the NO x -reducing composition is any NH-generating composition, preferably urea, it precursors and breakdown products effective under the conditions of contact with the exhaust to reduce the level of NO x .
  • the NO x -reducing compo ⁇ sition is preferably added to the diesel combustion gases, preferably to the cylinders of the diesel engine during the power or exhaust stroke at a temperature and pressure effec- tive in the time available to achieve NO x reduction.
  • the NO x -reducing composition is added at a time different from the injection of fuel but is preferably injected in much the same manner, either from the same injector (through a dif ⁇ ferent port) or through a separate, dedicated injector.
  • Figure 1 is a schematic representation of one embodi ⁇ ment of the invention wherein fuel and NO x -reducing composi- tion are introduced into the diesel engine through separate sets of injectors;
  • Figure 2 is a schematic, similar to that of Figure 1, but showing an embodiment wherein the fuel and NO x -reducing agent are introduced into the cylinders of a diesel engine through the same injectors.
  • diesel engine is meant to include those reciprocating engines capable of being run on “diesel fuel”, as defined by the American Society of Testing and Management (ASTM) Standard Specification for Fuel Oils (designation D 396-86) .
  • ASTM American Society of Testing and Management
  • diesel fuel can be fuel oil No. 2 or No. 4 petroleum distillates as well as alternative diesel fuels containing emulsified water or alcohols such as ethanol or methanol, as long as they exhibit volatility and cetane number characteristics effec ⁇ tive for the purpose.
  • the engines can have any practical number of cylinders and can be of four stroke or two stroke operation.
  • FIGS 1 and 2 each show a diesel engine 10, with an exhaust manifold 20, which leads to an exhaust system which preferably has a catalytic activity, e. g. a catalyst chamber 30, capable of reducing N0 X .
  • each engine is supplied with diesel fuel from a tank 40 and lines 42, 44, 44', 44" and 44"'.
  • the exhaust manifold 20 carries the hot combus ⁇ tion gases (exhaust) from the engine 10.
  • Figure 1 shows the combustion gases being treated by the introduction of a NO x -reducing composition, such as urea or an effective urea hydrolysis product, supplied from a container 50 through line 52 and a separate set of injectors 54, 54', 54" and 54"' .
  • the catalyst 30 is of a type effec ⁇ tive to facilitate reactions of ammonia, or other breakdown product of the NO x -reducing agent, with the NO x to achieve further NO x reduction.
  • Figure 2 shows the NO x -reducing composition introduced from tank 150 through line 152 to the same set of injectors used to inject the fuel.
  • the injectors will have separate ports for each of the fuel and the urea.
  • a suitable NO x -reducing agent is injected into each of the cylinders of the diesel engine at the proper time after injection of the fuel to avoid combustion of the NO x -reduc- ing agent but to react with the NO x for a suitable time and at a suitable temperature under the pressure prevailing in the gases.
  • suitable temperatures within the range of from about 1600" to 2000*F can be reached at the pressures prevailing, of from greater than 1 to about 12 atmospheres to give reaction times (between NO x and the NO x - reducing agent) within the range of from about 10 to about 50 milliseconds.
  • the exhaust is then passed through the ex- haust system which includes a catalyst of the type effective for N0 X reduction in the presence of urea or like NO x -reduc ⁇ ing agents or their breakdown products, such as in chamber 30, to reduce N0 X and ammonia produced by decomposition of the urea.
  • a catalyst of the type effective for N0 X reduction in the presence of urea or like NO x -reduc ⁇ ing agents or their breakdown products such as in chamber 30, to reduce N0 X and ammonia produced by decomposition of the urea.
  • the NO x -reducing agent can be present as urea, its precursors or any effective hydrolysis product.
  • Any compo ⁇ sition which generates an effective gas-phase agent such as an amidozine radical (NH-) or other active unoxidized by ⁇ product (e.g., NH 2 - or HNC0-), that is effective under the conditions of contact with the exhaust to reduce the level of NO x , can be employed.
  • Urea is an effective chemical for N0 X reduction at high temperature and/or high pressure, but can be replaced with one or more of its hydrolysis products.
  • NH-containing compositions in their pure and typi ⁇ cal commercial forms, will generate effective gas-phase agents (e.g., the amidozine radical) when introduced in aqueous solution and subjected to elevated temperatures.
  • gas-phase agents e.g., the amidozine radical
  • the gas-phase agents can be produced by the heat in the cylinders of the engine or by hydrolysis with heat and/or a catalyst prior to introduction into the cylinders.
  • NH-containing compositions those selected from the group consisting of ammonia, urea, urea precursors, urea hydrolysis products, products of reaction of urea with itself or other compositions, related compositions, and mixtures of these.
  • ammonium carbonate ammonium formate, ammonium citrate, ammonium acetate, ammonium oxalate, other ammonium salts (inorganic and organic) particularly of organic acids, ammonium hydroxide, various stable amines, guanidine, guani- dine carbonate, biguanide, guanylurea sulfate, melamine, dicyanimide, calcium cyana ide, cyanuric acid, biuret, 1,1- azobisformamide, methylol urea, methylol urea-urea, dimethyl urea, hexamethylenetetramine (HMTA) , and mixtures of these.
  • HMTA hexamethylenetetramine
  • ammonia carbamates such as ammonium carbamate, ammonium carbonate, ammonium bicarbonate and other ammonia salts, various urea complexes and half ammonia salts.
  • carbamates such as ammonium carbamate, ammonium carbonate, ammonium bicarbonate and other ammonia salts, various urea complexes and half ammonia salts.
  • the exact form of some of these compounds is not known because the techniques employed to analyze them can affect their makeup.
  • U.S. Patent No. 4,997,631 to Hofmann et al and PCT application WO 92/02291 to von Harpe et al are incorporated herein by reference.
  • the urea (representative of NO x -reducing compositions) is preferably added to the combustion gases as an aqueous solution or as a gas including hydrolyzed urea or the like.
  • the solution can be prepared ahead of time and added pre ⁇ mixed to the tank 50, 150 or the like, or the solution can be prepared as needed by mixing water with a water-soluble solid NO x -reducing agent.
  • the tank 50 or 150 holds only water which is metered through a cartridge holding solid NO x -reducing agent.
  • adding directly to the cylinders of the diesel is highly desirable — if done following the piston reaching top dead center and in a manner to take advantage of the natural mixing within the proper time for reaction at the effective temperature.
  • the solution is preferably injected at a point after top dead center, e.g. toward the end of the power stroke where the combustion gases are at a temperature of from about 1600" to about 2000"F.
  • Injection into the cylin- ders is preferably done in aqueous solution or in gaseous form.
  • the urea solutions typically can be from about 5 to about 50% urea, preferably from about 10 to about 25%, by weight.
  • Four-stroke diesel engines produce an exhaust at dis- charge from the cylinders into exhaust manifold 20, at an average temperature which is typically between about 500 ⁇ C and 600"C.
  • Two-stroke diesel engines produce an exhaust at manifold 20 which is typically at a lower temperature.
  • Fuel additives of the type disclosed in the above-noted U.S. Patent Application Serial No. 08/089,838 can be em ⁇ ployed if desired. The entire disclosure of that applica ⁇ tion is incorporated herein by reference.
  • a platinum group metal compound is added to the fuel to supply an amount of the platinum group metal within a range of about 0.01 to about 1.0 parts of the platinum group metal per one million parts of fuel (ppm w/v) in order to "build up" sufficient platinum group metal over time, for instance, between about 50 and 1000 hours of operation.
  • Suitable diesel particulate traps as known to the skilled artisan can be employed as necessary.
  • the additive can be provided at a ratio effective to provide a sufficient level of platinum group metal catalyst in a relatively short period of time, i.e., under about 10 hours, more preferably under about 5 hours. Effective concentrations for this purpose can range up to about 30 ppm, more advantageously, about 15 to about 25 ppm. These levels should be provided for about 0.5 to about 10 hours. Maintenance amounts of from about 0.1 to about 1.0 ppm can then be provided, to maintain superior activity.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Biomedical Technology (AREA)
  • Environmental & Geological Engineering (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Toxicology (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

Procédé d'amélioration du fonctionnement d'un moteur diesel (10) par l'intermédiaire de l'utilisation d'un additif de réduction de NOx (52) injecté dans les cylindres (au niveau de 54) du moteur. La réduction de NOx s'effectue au niveau de ce point, ainsi qu'en aval du système d'échappement (20) où on utilise un catalyseur de réduction de NOx (30).
PCT/US1994/008582 1993-07-29 1994-07-29 PROCEDE DE REDUCTION DES EMISSIONS DE NOx DE MOTEURS DIESEL WO1995004211A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU74082/94A AU7408294A (en) 1993-07-29 1994-07-29 Method for reducing nox emissions from diesel engines

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US9920893A 1993-07-29 1993-07-29
US08/099,208 1993-07-29

Publications (1)

Publication Number Publication Date
WO1995004211A1 true WO1995004211A1 (fr) 1995-02-09

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Application Number Title Priority Date Filing Date
PCT/US1994/008582 WO1995004211A1 (fr) 1993-07-29 1994-07-29 PROCEDE DE REDUCTION DES EMISSIONS DE NOx DE MOTEURS DIESEL

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AU (1) AU7408294A (fr)
WO (1) WO1995004211A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007130212A1 (fr) * 2006-04-25 2007-11-15 Caterpillar Inc. SYSTÈME permettant d'AUGMENTER L'EFFICACITÉ D'UN CATALYSEUR SCR
US8048390B2 (en) 2006-12-23 2011-11-01 Alzchem Trostberg Gmbh Method for the selective catalytic reduction of nitrogen oxides in exhaust gases of vehicles
WO2016201144A1 (fr) * 2015-06-10 2016-12-15 Sturman Digital Systems, Llc Combustion d'ammoniac dans des moteurs diesel à deux carburants

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4452040A (en) * 1980-11-17 1984-06-05 Toyota Jidosha Kabushiki Kaisha Soot catcher purgative diesel engine fuel supply method and apparatus
US4854123A (en) * 1987-01-27 1989-08-08 Nippon Shokubai Kagaku Kogyo Co., Ltd. Method for removal of nitrogen oxides from exhaust gas of diesel engine
JPH03253713A (ja) * 1990-03-01 1991-11-12 Mitsubishi Heavy Ind Ltd 内燃機関の脱硝装置
US5224346A (en) * 1991-05-16 1993-07-06 James W. Davis Engine NOx reduction system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4452040A (en) * 1980-11-17 1984-06-05 Toyota Jidosha Kabushiki Kaisha Soot catcher purgative diesel engine fuel supply method and apparatus
US4854123A (en) * 1987-01-27 1989-08-08 Nippon Shokubai Kagaku Kogyo Co., Ltd. Method for removal of nitrogen oxides from exhaust gas of diesel engine
JPH03253713A (ja) * 1990-03-01 1991-11-12 Mitsubishi Heavy Ind Ltd 内燃機関の脱硝装置
US5224346A (en) * 1991-05-16 1993-07-06 James W. Davis Engine NOx reduction system

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007130212A1 (fr) * 2006-04-25 2007-11-15 Caterpillar Inc. SYSTÈME permettant d'AUGMENTER L'EFFICACITÉ D'UN CATALYSEUR SCR
US7428810B2 (en) 2006-04-25 2008-09-30 Caterpillar Inc. System for increasing efficiency of an SCR catalyst
US8048390B2 (en) 2006-12-23 2011-11-01 Alzchem Trostberg Gmbh Method for the selective catalytic reduction of nitrogen oxides in exhaust gases of vehicles
US8652426B2 (en) 2006-12-23 2014-02-18 Alzchem Trostberg Gmbh Use of aqueous guanidinium formate solutions for the selective catalytic reduction of nitrogen oxides in exhaust gases of vehicles
KR101558878B1 (ko) * 2006-12-23 2015-10-08 알즈켐 아게 차량 배기가스 중의 질소 산화물의 선택적 촉매 환원을 위한 방법
WO2016201144A1 (fr) * 2015-06-10 2016-12-15 Sturman Digital Systems, Llc Combustion d'ammoniac dans des moteurs diesel à deux carburants

Also Published As

Publication number Publication date
AU7408294A (en) 1995-02-28

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