Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/34—Chemical or biological purification of waste gases
  • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
  • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
  • B01D53/9404—Removing only nitrogen compounds
  • B01D53/9409—Nitrogen oxides
• • 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
  • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
  • B01D53/86—Catalytic processes
  • B01D53/90—Injecting reactants
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
  • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion
  • F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
  • F01N3/2066—Selective catalytic reduction [SCR]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2251/00—Reactants
  • B01D2251/20—Reductants
  • B01D2251/206—Ammonium compounds
  • B01D2251/2062—Ammonia
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2251/00—Reactants
  • B01D2251/20—Reductants
  • B01D2251/206—Ammonium compounds
  • B01D2251/2067—Urea
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N2610/00—Adding substances to exhaust gases
  • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea

Definitions

• Application WO2008/125745 describes an aqueous solution comprising a compound capable of releasing gaseous ammonia above 200°C and at least one polyfunctional additive whose HEB varies from 7 to 17 to limit the formation of deposits based on cyanuric acid in an exhaust gas post-treatment device, in particular of the SCR type.
• These polyfunctional additives used are in particular polyalkoxylated fatty alcohol ethers and polyalkoxylated fatty alcohol esters.
• aqueous ammonia precursor solutions containing surfactants tend to foam.
• This foaming occurs in particular during transport and handling of the solution, for example during its unloading into the storage tanks, then when the composition is introduced from a storage tank into the tank of a vehicle, which complicates the tank filling operation and may cause it to overflow.
• the common use of guns when distributing the composition also promotes foaming.
• the foaming of the composition when it occurs at the time of its injection into the vehicle's exhaust gas treatment system can result in the introduction of a more or less significant quantity of air into said system. This phenomenon disrupts the control of the quantity of solution injected and affects the efficiency of the treatment system.
• the present invention also relates to the use of such a composition for the treatment of exhaust gases from on-board or stationary internal combustion engines, more particularly for the treatment of exhaust gases in a selective catalytic reduction device. nitrogen oxides.
• the engine can be chosen in particular from Diesel engines, spark ignition engines (including gasoline engines and CNG or natural gas engines for vehicles), and mixed carburetion engines, in particular diesel-gas.
• the engine is a Diesel engine.
• the present invention applies to any type of engine likely to emit nitrogen oxides, including on-board engines and stationary engines.
• the invention applies, among others, to marine engines, heavy goods vehicle engines, transport vehicles, construction machinery or agricultural machinery such as for example tractors, as well as engines for light and utility vehicles, as well as engines used in stationary industrial applications.
• SCR device for “Selective Catalytic Reduction” in English.
• SCR catalyst a Selective Catalytic Reduction catalyst
• the invention also relates to a process for treating exhaust gases from an internal combustion engine, preferably a diesel engine, equipped with a device for the selective catalytic reduction of nitrogen oxides, this process being characterized in that that it comprises at least one step of introducing a composition as defined above into the pipe which routes the exhaust gases from the engine outlet to said selective catalytic reduction device.
• SCR exhaust line or SCR line, in a manner known per se, the pipe which routes the exhaust gases from the outlet of an engine to a selective catalytic reduction device (SCR device ) .
• SCR device selective catalytic reduction device
• the composition according to the invention has numerous advantages: it can be used in the same way and in the same equipment as the solutions of the prior art. It is at least as effective, or even more effective, than the solutions of the prior art, in particular solutions based on urea in reducing or preventing the formation of deposits in SCR systems, in particular in so-called configurations. “close-coupled” . It causes no or very little foaming during its handling, use, transfer and/or transport, for example during transfer operations or filling of containers such as cans, vehicle tanks, tanks. storage or transport tanks. In particular, it helps prevent overflows when filling a vehicle's storage tank. It also makes it possible to fill storage tanks and vehicle tanks more quickly, and in the latter case by limiting the jerks of the filling guns. This composition also allows precise control of the quantity of composition injected, and in particular makes it possible to avoid errors linked to the faulting of the sensors by the foam.
• composition according to the invention is stable on storage. It also has anti-foam performance maintained over time, particularly over periods of up to one year, over a wide range of storage temperatures, ranging from 5°C to 40°C.
• CN compound or group denotes a compound or group containing N carbon atoms in its chemical structure.
• composition used in the invention comprises at least one nitrogen oxide reducing agent and/or at least one precursor of a nitrogen oxide reducing agent (1).
• nitrogen oxide reducing agent is meant a compound capable of reducing at least partially, if not entirely, nitrogen oxides (also called NOx to designate the compounds NO and NO2) to nitrogen, under conventional conditions.
• operating mode of an SCR line that is to say in the presence of an SCR catalyst and at a temperature ranging from 150 to 400°C.
• NOx reducing agents we can particularly mention ammonia (NH3).
• precursor of a NOx reducing agent is meant a compound capable of releasing a NOx reducing agent under the effect of temperature and/or by catalytic reaction.
• the SCR exhaust line may comprise, upstream of the SCR catalytic system, a catalyst whose function is to transform a precursor of a NOx reducing agent into a NOx reducing agent, in particular into gaseous ammonia.
• the reducing agent or the precursor of the reducing agent is chosen from the list consisting of urea, ammonia, formamide, ammonium salts, in particular ammonium formate, carbamate of ammonium, and guanidine salts, in particular guanidinium formate; and preferably in the list consisting of urea and ammonia.
• urea is used, which is a reducing agent precursor.
• urea has the advantage of being stable, non-volatile, non-explosive and non-flammable. It can be transported without risk, stored and handled by an operator without specific training.
• the composition has a urea content ranging, preferably, from 25% to 42% by mass, more preferably from 30% to 40% by mass, even more preferably from 31 to 35% by mass and better still another 32% to 33% by mass, relative to the total mass of the composition.
• the composition contains urea at a content of 32.5 ⁇ 0.7% by mass, in accordance with the specifications of standard ISO 22241 - 1.
• the aqueous solution according to the invention is prepared from the commercial product AdBlue®, which is an aqueous solution of urea at 32.5 ⁇ 0.7% by mass.
• AdBlue® is used in this description to designate indifferently the commercial products well known under the following names: AdBlue®, DEF, AUS32, ARLA32.
• AdBlue® By extension, under this name we mean the whole products from the AdBlue® range, including the product marketed under the name AUS40 which corresponds to an aqueous solution of urea at approximately 40% by mass and is mainly intended for marine engines.
• aqueous compositions containing urea with a concentration greater than 32.5% which can then be diluted just before use. This variant allows savings to be made during the transport of these urea-based compositions.
• composition according to the invention contains at least one additive (2) chosen from block copolymers formed of at least one poly(ethylene oxide) block or EO block or PEG block for polyethylene glycol and at least one block poly(propylene oxide) or PO block or PPG block for polypropylene glycol.
• additive (2) chosen from block copolymers formed of at least one poly(ethylene oxide) block or EO block or PEG block for polyethylene glycol and at least one block poly(propylene oxide) or PO block or PPG block for polypropylene glycol.
• the copolymer(s) (2) are poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) triblock polymers or poloxamers.
• These triblock polymers correspond to the following formula (I): H(OCH 2 CH2)a(OCH(CH3)CH2)b(OCH 2 CH2)cOH (I) in which a, b and c are integers strictly greater than 1.
• said triblock polymers are chosen from those of formula (I) above, in which: a is in the range from 2 to 15, b is in the range from 15 to 60 and c is in the range the range going from 2 to 15. More preferably, a is included in the range going from 4 to 10, b is included in the range going from 20 to 40 and c is included in the range going from 4 to 10.
• said copolymers (2) are chosen from poloxamers 182, that is to say copolymers comprising 20% by mass of ethylene oxide and 80% by mass of propylene oxide.
• the copolymers (2) advantageously have a molar mass in number MN in the range going from 500 to 5000. They advantageously have a molar mass by weight Mw in the range from 1000 to 5000.
• the copolymer(s) (2) are present at a total content of 100 to 1500 ppm by mass, preferably 200 to 1000 ppm by mass and better still 350 to 750 ppm by mass, relative to the total mass of the composition .
• the composition according to the invention further comprises one or more anti-foam additive(s), preferably chosen from grafted polydimethylsiloxane polymers.
• the anti-foam additive(s) are chosen from copolymers comprising a polydimethylsiloxane skeleton with an average number of dimethylsiloxane units in the range from 150 to 300, grafted by polyoxyalkylene chains.
• copolymers are therefore grafted polymers, with a polydimethylsiloxane backbone and polyoxyalkylene side chains (or grafts) grafted onto the backbone.
• the skeleton of these polymers consists of a polydimethylsiloxane chain (also commonly called PDMS), that is to say a chain of formula -[Si(CH3)2-O] n -, with n a number included in the range going from 150 to 300.
• PDMS polydimethylsiloxane chain
• the polydimethylsiloxane skeleton comprises an average number of dimethylsiloxane units in the range of 180 to 250. This corresponds to a value of the number n in the range of 180 to 250.
• the polyoxyalkylene chains grafted onto the polydimethylsiloxane skeleton advantageously correspond to the formula -(RO) m - with R designating one or more alkylene groups in C l to C4, branched or linear, preferably in C2 or C3, and m a number included in the range from 10 to 55.
• the average number m of oxyalkylene units is in the range from 20 to 50, more preferably from 30 to 50.
• R, R' and R" are chosen from C4-C50 alkynyls.
• this embodiment concerns formula (III), in which R" is a C4-C50 alkynyl.
• this embodiment concerns formula (I), in which R represents a group chosen from aralkyls comprising from 9 to 30 carbon atoms.
• R is chosen from para-alkylphenyls comprising a C1-C24 alkyl group, more preferably a C3-C20 alkyl group, and better still a C5-C18 alkyl group.
• the compounds of formula (I) can advantageously be mixtures obtained by reaction of R-OH alcohols with n units of ethylene oxide and/or propylene oxide.
• n represents the number of moles of alkylene oxide reacted with one mole of alcohol R-OH.
• the compounds of formula (II) may advantageously be mixtures obtained by reaction of R-OH alcohol compounds with m units of ethylene oxide and/or propylene oxide followed by an etherification reaction with an alcohol compound.
• R' -OH. m represents the number of moles of alkylene oxide that were reacted with one mole of alcohol R-OH.
• the compounds of formula (III) can advantageously be obtained by reaction of a HO- R"-OH diol with (n+m) units of ethylene oxide and/or propylene oxide.
• n m.
• (m+n) represents the number of moles of alkylene oxide that were reacted with one mole of HO-R"-OH diol.
• the compounds of formula (I), (H) and (III) are generally in the form of mixtures of compounds having varying degrees of alkoxylation.
• Hydrocarbyl and polyol ethers are generally in the form of mixtures of compounds having varying degrees of alkoxylation.
• hydrocarbyl and polyol ethers are advantageously chosen from ethers derived from an alcohol comprising a C1-C50 alkyl or alkenyl group, preferably C3-C40, more advantageously C5-C32, even better C8-C30 , and a polyol.
• the polyols referred to here are different from mono and polyalkylene glycols.
• the polyol is chosen from compounds belonging to the carbohydrate family and their oligomers.
• the polyol is chosen from cyclic carbohydrate compounds, such as for example glucopyranose oligomers.
• the invention relates in particular to hydrocarbyl and cyclic polyglucoside ethers.
• alkyl polyglucosides such as the product marketed under the name Triton CG650® by the company Dow Chemical.
• the polyol is glycerol or a glycerol oligomer, for example an oligomer comprising 2 to 30 glycerol units, preferably 3 to 20 glycerol units.
• Esters of fatty acid and mono or polyalkylene glycol are molecules resulting from the condensation of at least one fatty acid with 1 to 60 alkylene glycol units, preferably 1 to 50 alkylene glycol units.
• they come from the reaction of a fatty acid with 1 to 50 ethylene glycol units.
• Fatty acids are generally molecules comprising an alkyl or alkenyl chain, carrying a carboxylic acid function at its end, and comprising 4 to 30 carbon atoms, preferably 8 to 30 carbon atoms, more preferably 8 to 24 atoms. of carbon.
• the fatty acid group can be a single molecule or a mixture corresponding to the fatty acid distribution of an animal or vegetable oil.
• fatty acids mention may be made, in a non-limiting manner, of a saturated fatty acid such as n-caproic acid, caprylic acid, n-capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, arachidic acid or an unsaturated fatty acid such as palmitoleic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid or docosahexaenoic acid.
• a saturated fatty acid such as n-caproic acid, caprylic acid, n-capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, arachidic acid or an unsaturated fatty acid such as palmitoleic acid, oleic acid, l
• esters of fatty acids and mono or polyalkylene glycol advantageously comprise from 3 to 50, even better from 5 to 40 alkylene oxide units. Even better, the esters of fatty acids and mono or polyalkylene glycol comprise from 3 to 50, advantageously from 5 to 40 ethylene oxide units.
• esters of fatty acids and polyalkylene glycols we can cite the product DUB S PEG 30S (PEG-30 stearate) marketed by the company Stéarinerie Dubois.
• Fatty acid and mono or polyglycerol esters are molecules resulting from the condensation of at least one fatty acid with 1 to 60 alkylene glycol units, preferably 1 at 50 glycerol units.
• the fatty acids are identical to those described in point c) above.
• esters of fatty acids and mono or polyglycerol advantageously comprise from 3 to 50, even better from 5 to 40 glycerol units.
• esters of fatty acids and polyglycerol we can cite the product Polyaldo 10-1-0 KEG® (polyglycerol laurate) marketed by the company LONZA.
• the surfactant(s) are chosen from nonionic surfactants. It is particularly preferred to use one or more surfactants chosen from hydrocarbyl and mono or polyalkylene glycol ethers, and more preferably from mono- or poly-alkoxylated hydrocarbyl monoethers of formula (I): R-(Y) n -OH, in which: R represents a C3-C40 alkyl, alkenyl or alkynyl group, preferably C8-C30, even more preferably C10-C24;
• Y is chosen from: -(O-CH2-CH2)-, -(O-CH(CH 3 )-CH 2 )- and -(O-CH 2 - CH2-CH2)-; and preferably Y denotes -(O-CH2-CH2)-; n is an integer ranging from 1 to 60, preferably from 1 to 30, more preferably from 1 to 20, better from 3 to 15, even better from 5 to 12.
• the composition further comprises at least one additional surfactant chosen from linear or branched polyalkoxylated fatty alcohols comprising from 4 to 30 carbon atoms, preferably 8 to 30 carbon atoms, better still 10 to 24 carbon atoms. carbon; and from 5 to 12 ethylene oxide and/or propylene oxide units, preferably ethylene oxide.
• additional surfactant chosen from linear or branched polyalkoxylated fatty alcohols comprising from 4 to 30 carbon atoms, preferably 8 to 30 carbon atoms, better still 10 to 24 carbon atoms. carbon; and from 5 to 12 ethylene oxide and/or propylene oxide units, preferably ethylene oxide.
• the total content of additional surfactants, when present, can range from 5 to 1000 ppm by mass, preferably from 10 to 500 ppm by mass, and better still from 50 to 150 ppm by mass, relative to the total mass of the composition.
• the aqueous composition may optionally contain one or more other compounds, other than the nitrogen oxide reducing agents and their precursors, PEG and PPG boc copolymers, anti-foam additives and additional surfactants described above.
• composition may thus comprise, in a non-limiting manner, one or more organic fluids miscible with water such as for example alcohols, polyols, and/or one or more metal compounds.
• the composition according to the invention does not contain paraffins.
• paraffins we designate alkanes of formula C n H2n+2, with n an integer ranging from 2 to 50, preferably from 6 to 40, more preferably from 18 to 35.
• not containing paraffins we mean means that the composition does not contain intentionally added paraffins.
• such paraffins are present in the composition, they are considered as impurities and their content is less than 80 ppm by mass, preferably less than 50 ppm by mass, better still less than 20 ppm by mass and better still less than 10 ppm by mass, relative to the total mass of the composition.
• the composition according to the invention does not comprise any metallic compound(s).
• metallic compound we designate any compound, organic or inorganic, comprising one or more metals. These compounds can be ionic or non-ionic. In particular, the composition does not include organometallic compounds or inorganic metal compounds, whether ionic or non-ionic.
• Examples of ionic compounds excluded according to this embodiment are in particular compounds comprising one or more metals chosen from the following metals: Fe, Cu, Ni, Co, Zn, Mn, Mg, Ti, V, Sr, Pt, Ce, Ca, Li, Na, and Nb.
• not containing metal compounds it is meant that the composition does not contain such voluntarily added compounds. Thus, if such compounds are present in the composition, they are considered as impurities and the content of each metallic element provided by said metal compound(s) is less than 1 ppm by mass, in particular less than 0.5 ppm by mass , relative to the total mass of the composition.
• the composition used in the present invention is a composition which comprises a single liquid phase, of aqueous nature.
• this composition comprises a single liquid phase whose main component is water.
• the water content of the composition is preferably in the range going from 50 to 90% by mass, preferably from 60 to 80% by mass, and better still from 65 to 70% by mass, relative to the total mass. of the composition.
• composition according to the invention does not comprise a liquid phase, other than the aqueous phase above.
• the composition does not comprise a hydrocarbon liquid phase, including in dispersed form (oil-in-water emulsion).
• liquid phase we designate a phase which is in the liquid state at 25°C and at atmospheric pressure (1.013.10 5 Pa).
• phase whose solubility in water at 25 ° C and at atmospheric pressure (1.013.10 5 Pa) is less than 2% by weight, and preferably less than 1%. by weight, even more preferably less than 0.5% by weight.
• composition according to the invention is not in the form of an emulsion.
• emulsion we designate in a manner known per se a composition comprising at least two liquid phases, one of the phases being dispersed in the form of droplets in the other phase.
• the composition can be prepared in the usual manner by mixing its constituents, preferably at room temperature, typically in a temperature range generally ranging from 10 to 60°C.
• the aqueous composition is prepared from a preformulated aqueous solution of urea, such as for example a commercial composition known under the name AdBlue® comprising 32.5% by weight of urea.
• AdBlue® a commercial composition known under the name AdBlue® comprising 32.5% by weight of urea.
• a first embodiment consists of adding the block copolymer(s) (2) and the optional anti-foam additive(s) to this preformulated aqueous urea solution, in the quantity required to achieve the contents defined below. -Before.
• a second embodiment consists of adding to this preformulated aqueous urea solution a concentrated aqueous composition of additive urea.
• the concentrated aqueous composition of additive urea comprises the block copolymer(s) (2) (2) and the optional anti-foam additive(s) at contents much higher than that of the final aqueous composition introduced into the SCR line, in an aqueous urea solution, preferably at a content of 32.5% by weight of urea.
• the mixing of the two compositions in an appropriate ratio to obtain the desired final contents is carried out just before injection into the SCR line.
• the same embodiments can be implemented from a preformulated aqueous solution of a precursor other than urea.
• the aqueous composition according to the invention is used to treat the exhaust gases leaving an internal combustion engine in a device for the selective catalytic reduction of nitrogen oxides or SCR device.
• the composition is introduced into the SCR exhaust line, downstream of the engine and upstream of the SCR device.
• This introduction is typically carried out by pumping the composition from one or more tanks and injecting it by means of one or more injectors, which allow the composition to be sprayed into the exhaust gas flow.
• injectors which allow the composition to be sprayed into the exhaust gas flow.
• the use according to the invention also makes it possible to prevent or reduce deposits in the pipe which routes the exhaust gases from the outlet of an internal combustion engine to said selective catalytic reduction device.
• These deposits are typically deposits of nitrogen compounds, containing the reducing agent(s) of nitrogen oxides and/or their precursor(s), and/or decomposition products of said precursors.
• the invention makes it possible in particular to prevent and/or reduce urea and/or cyanuric acid deposits, and more particularly cyanuric acid deposits in the SCR exhaust pipe.
• the invention makes it possible to reduce or avoid these deposits whatever the conformation of the SCR line.
• the invention is particularly, but not limited to, suitable for so-called “close-coupled” and “underfloor” SCR exhaust lines as described above.
• the invention makes it possible to reduce such deposits, while avoiding the phenomena of foaming of the composition.
• the composition injected into the SCR line is pumped from one or more conventional storage tanks, known per se.
• all the components of the composition according to the invention in particular the reducing agent(s) of nitrogen oxides and/or their precursor(s) (1), the or the block copolymers (2) and the optional anti-foam additive(s) are formulated in the same aqueous composition at the desired contents, and this composition is introduced into a single tank.
• a first intermediate aqueous composition comprising the nitrogen oxide reducing agent(s) and/or their precursor(s) (1), at the desired levels in the composition. final resulting from the mixture of the two intermediate compositions.
• This first intermediate composition is introduced into a first tank.
• a second additive concentrated intermediate aqueous composition is also formulated, comprising the nitrogen oxide reducing agent(s) and/or their precursor(s) (1) at the desired levels in the resulting final composition. of the mixture of the two intermediate compositions, as well as the block copolymer(s) (2) and the optional anti-foam additive(s) in a more concentrated content than the desired content in said final composition.
• This second composition is introduced into a second tank, separate from the first tank.
• the two tanks feed the same injection system, allowing the mixing of the two intermediate compositions.
• a vehicle comprising two tanks for implementing such a variant is described in particular in EP2541012.
• the process (or method) according to the invention makes it possible to treat the exhaust gases coming from an internal combustion engine, preferably a Diesel engine, equipped with an SCR system.
• This process comprises a step of introducing an aqueous composition as described above into the pipe conveying the exhaust gases leaving an engine to a device for the selective catalytic reduction of nitrogen oxides.
• This introduction is typically carried out by pumping the composition from of one or more tanks and injecting it into said pipe by means of one or more injectors, as described above.
• Additivated compositions C l to C3 were prepared, by adding to the composition CO the additives defined above, with the contents detailed in Table 1 below (contents indicated by mass of active ingredient, relative to the total mass composition):
• the deposit reduction capacity of the additive compositions C l to C3 in comparison with the reference composition CO was evaluated using the ECTO-LabTM system (“Exhaust Composition Transient Operation LaboratoryTM”). These tests were carried out in the laboratories of the South West Research Institute (SwRI, San Antonio, Texas, USA).
• the system also has an oxidation catalyst and particle filter device (device called “DOC/DPF” from English “Diesel Oxidation Catalyst/Diesel Particle Filter” upstream of the injector to remove soot from the gas exhaust.
• DOC/DPF oxidation catalyst and particle filter device
• a Bosch Denoxtronix 2.2 injector was used. A static mixer is incorporated 5 cm after the injector. At the end of the test the mass quantities of deposits in the mixer and in the elbow located after the mixer are quantified .
• compositions according to the invention make it possible to obtain a substantial reduction in the deposits generated by the crystallization and/or poor decomposition of urea in the SCR system.
• the foaming level of these different compositions was determined using a DFA 100 foaming bench sold by the company Krüss. In this system, foaming is generated by the supply of ascending air, introduced through a sintered glass located at the bottom of a column containing the composition to be tested. The device allows direct reading of the volume of foam formed as a function of time. The measurements were carried out at room temperature (25°C), each time after an air injection duration of 30 s, at a flow rate of 0.3 L/min. The volume of composition introduced into the column for each test is 40 ml. The foam volumes were measured 50 s after the start of the test. Each composition was tested immediately after its preparation
• compositions C2 and C3 also make it possible to substantially reduce foaming.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Environmental & Geological Engineering (AREA)
• Health & Medical Sciences (AREA)
• Analytical Chemistry (AREA)
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• General Chemical & Material Sciences (AREA)
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• General Engineering & Computer Science (AREA)
• Toxicology (AREA)
• Mechanical Engineering (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Treating Waste Gases (AREA)
• Polyethers (AREA)
• Exhaust Gas After Treatment (AREA)
• Exhaust Gas Treatment By Means Of Catalyst (AREA)

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• 2023
  • 2023-08-28 JP JP2025512571A patent/JP2025531045A/ja active Pending
  • 2023-08-28 CN CN202380062866.2A patent/CN119768221A/zh active Pending
  • 2023-08-28 AR ARP230102277A patent/AR130321A1/es unknown
  • 2023-08-28 EP EP23772299.6A patent/EP4580783A1/de active Pending
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