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    • 专利摘要:
    The present invention describes a fluid adapted to the depollution of the thermal engines making it possible both to carry out the catalytic reduction of the nitrogen oxides (DeNOx) contained in the exhaust gases and to assist the regeneration of the particulate filter (DPF). , said fluid being in the form of a stable suspension of colloidal particles, these colloidal particles being dispersed in an aqueous solution containing at least one reducing agent or at least one precursor of a NOx reducing agent. The invention also describes several methods for obtaining said fluid.
    公开号:FR3043568A1
    申请号:FR1560906
    申请日:2015-11-13
    公开日:2017-05-19
    发明作者:Eric Lecolier；Patrick Gateau；Stephane Zinola；Nathalie Palazzo
    申请人:IFP Energies Nouvelles IFPEN；
    IPC主号:
    专利说明:

    FIELD OF THE INVENTION
    The present invention describes a unique fluid for automotive pollution control, enabling two distinct operations to be carried out: the selective catalytic reduction of NOx using Selective Catalytic Reduction technology, commonly referred to by its English name Selective Catalytic Reduction, or by the acronym SCR, as well as the aid for the regeneration of the particulate filter (DPF), this regeneration aid being able to be manifested either by the promotion of the continuous regeneration of the particle filter, or by the acceleration of the combustion of the soot during active regeneration phases of the FAP, either by a combination of these two advantages. The composition according to the invention is homogeneous and exhibits stability characteristics over time, or during variations in temperature or pH. The present invention describes different modes of obtaining the fluid as well as the mode of use of this fluid.
    PRIOR ART
    Different technologies are implemented to reduce the harmful emissions of diesel engine exhaust fumes, including nitrogen oxides (NOx) and particulate matter.
    An example of an exhaust system integrating the NOx treatment system by selective catalytic reduction, (SCR abbreviation of Selective Catalytic Reduction in the English terminology), and the particulate filter (abbreviated FAP), is given in the patent FR 2947004. These two systems of pollution can also be grouped in a single module, this one being known under the term of SCR on filter or SCRF or SDPF or SCRoF.
    We have not found in the literature a fluid composition allowing to cumulate the functions of reduction of the oxides of nitrogen and help with the regeneration of the particles of trapped soot. AdBlue® (or AUS32 or DEF or ARLA32) is a solution of 32.5% by weight urea in pure water, which is used for the selective reduction of nitrogen oxides as part of the technology. SCR for road and non-road applications.
    The general concept of pooling these depollution functions was the subject, at the end of 2014, of the filing of the French patent application 14 / 62.228. This request can be considered as a refinement of the application 14 / 62.228
    SUMMARY DESCRIPTION OF THE INVENTION
    The present invention describes a fluid for the depollution of heat engines, in particular diesel engines, making it possible to carry out both the selective catalytic reduction of the nitrogen oxides contained in the exhaust gas (so-called SCR function), as well as the assistance to the regeneration of the particulate filter (FAP) by catalytic combustion of soot particles deposited in the particulate filter (so-called FAP regeneration aid function), this regeneration aid being able to be manifested either by the promotion of the regeneration continuously in the particulate filter, either by accelerating the soot combustion during active regeneration phases of the FAP, or by a combination of these two advantages. The use of the soot oxidation catalyst differs from the previously cited prior art in that it is injected directly into the exhaust thus not passing through the combustion chamber of the engine. The injection of the fluid according to the invention is triggered by the engine computer to meet a need to have the necessary amount of ammonia on the SCR catalyst to operate the effective reduction of NOx. The injections are carried out regularly, in a period typically between a few milliseconds and a few tens of seconds depending on the operating conditions of the engine, which allows to promote a homogeneous mixture of the catalyst with the soot and to ensure an intimate contact between soot and catalyst.
    In fine, the fact of injecting the fluid according to the invention makes it possible either to promote the phenomenon of continuous regeneration of the particulate filter and thus to space the active regeneration periods of the FAP, ie to accelerate the combustion of the soot during active regeneration phases of the FAP, to limit the fuel consumption relative to this phase and / or maximize the chances of burning a large soot mass when the conditions of temperature and gas composition at the exhaust are favorable to this active regeneration, a combination of both.
    The fluid according to the invention is in the form of a stable suspension of colloidal particles incorporating one or more atomic elements known to catalyze the combustion of soot, these colloidal particles being dispersed in an aqueous solution containing at least one reducing agent or at least one a precursor of a NOx reducing agent. The colloidal particles used according to the invention contain at least one of the following metals: Fe, Cu, Ni, Co, Zn, Mn, Ti, V, Sr, Pt, Ce, Ca, Li, Na, Nb.
    The colloidal particles may be either oxides or metal oxyhydroxide particles or metal carbonates or a combination of both.
    The compositions of the fluid according to the invention consist of a dispersion of colloidal particles of oxides or of metal oxyhydroxides or of metal carbonates in a solution of at least one reducing compound or precursor of a reducing agent, the one or more metals of the oxides or metal oxyhydroxides or metal carbonates being selected from the following metals list: Fe, Cu, Ni, Co, Zn, Mn, Ti, V, Sr, Pt, Ce, Ca, Li, Na, Nb.
    Preferably, the metal (s) of the one or more metal oxides or oxyhydroxides or metal carbonates are chosen from the following list: Fe, Ce, Cu, Sr.
    Preferably, the reducing compound (s) or the precursor (s) of a reducing agent in aqueous solution are selected from urea, ammonia, formamide, and ammonium salts, in particular ammonium formate, ammonium carbamate, guanidine salts, especially guanidinium formate.
    Preferably, the concentration of metal oxides or oxyhydroxides or of metal carbonates is such that the concentration of metal ions in the solution of the reducing compound or precursor of a reducing agent is between 10 and 10,000 ppm, preferably between 10 and 5,000. ppm, and preferably between 10 and 2000 ppm.
    According to a preferred variant of the invention, the dispersion of colloidal particles consists of oxides or oxyhydroxides or iron carbonates of mineral or synthetic origin.
    According to a variant of the invention, the iron oxides taken alone or as a mixture are chosen from the following list: wustite FeO, hematite a-FeiCL, maghemite y-FeiCF, magnetite.
    According to another variant of the invention, the iron oxyhydroxides taken alone or as a mixture are chosen from the following list: goethite a-FeO (OH), lepidocrocite y-FeO (OH), feroxyhyte δ-FeO ( OH), Akaganéite P-FeO (OH), ferrihydrite FcsOx-dfLO, bemalite Fe (OH) 3, ferric hydroxide Fe (OH).
    According to another preferred variant of the invention, the dispersion of colloidal particles consists of oxides or hydroxides or copper carbonates of mineral or synthetic origin.
    According to another preferred variant of the invention, the dispersion of colloidal particles consists of oxides or oxyhydroxides or cerium carbonates of mineral or synthetic origin.
    According to another preferred variant of the invention, the dispersion of colloidal particles consists of oxides or oxyhydroxides or strontium carbonates of mineral or synthetic origin.
    According to another variant of the invention, the reducing agent or the reducing agent precursor is urea at 32.5 ± 0.7% by mass in solution in demineralised water or in pure water corresponding to to the specifications of ISO 22241.
    According to a very preferred variant of the present invention, the solution containing the reducing compound (s) or the precursor (s) of a reducing agent of the reducing compound is prepared from a product meeting the specifications of the ISO 22241 standard, for example commercial products AdBlue®, DEF, AUS32 or ARLA32.
    According to another preferred variant of the present invention, the solution containing the reducing compound (s) or the precursor (s) of a reducing agent is prepared from a product that complies with the physical and chemical characteristics of the ISO 22241-1 standard, for example the commercial product Diaxol®.
    Thereafter, the term Adblue® will be used to refer to the following products: Adblue®, DEF, AUS32, ARLA32 or Diaxol®.
    The present invention also relates to a method for manufacturing the fluid for engine depollution.
    The manufacturing process consists in dispersing colloidal particles incorporating at least one metal in an aqueous solution containing at least one reducing agent or at least one precursor of an NOx reducing agent.
    When the material of which the colloidal particles are made has an isoelectric point greater than 12 or less than 7, the particles may be directly dispersed in an aqueous solution whose pH is between 9 and 10 and containing at least one reducing agent or at least a NOx reducing agent precursor. In this case a so-called particle operation step is not a priori necessary. In this case the colloidal particles can be directly dispersed in a solution of AdBlue®, the colloidal particle suspension thus obtained being stable with respect to aggregation and sedimentation.
    In the case where the isoelectric point of the material of which the colloidal particles are made is in the range 7 to 12, then a step of functionalizing said particles is still necessary.
    In the general case, the process for manufacturing the fluid for the engine depollution according to the present invention consists of the following sequence of steps: a) synthesis of the particles of oxides or of oxyhydroxides or of metal carbonates, b) functionalization particles of oxides or oxyhydroxides or metal carbonates by organic molecules or by coating to stabilize these particles in the aqueous solution containing a reducing agent or precursor of an NOx reducing agent, • c) purification by filtration, or filtration-washing, or rinsing, or dialysis, processes applied alone or in combination, suspensions of particles of oxides or oxyhydroxides or metal carbonates, • d) dispersion of particles of oxides or oxyhydroxides or metal carbonates functionalized in an aqueous solution containing at least one reducing agent or at least one NOx reducing agent precursor in one of the following modes: o mechanical stirring using an agitator equipped with either a propeller shaft comprising a certain number of blades, or any other equipment known to ensure effective stirring of the suspension stirring with a high shear homogenizer-disperser stirring with a colloid mill • e) dispersion using an ultrasound probe Step e) is either performed according to the result and efficiency obtained at the end of the mechanical dispersion step of step d) (in this case this step e) is optional), is performed in place of the mechanical stirring step of step d).
    According to a variant of the process for manufacturing the fluid for the engine depollution according to the invention, the step b) of functionalization of the particles of oxides or of oxyhydroxides or of metal carbonates is carried out by using organic molecules of ionic polymer type carrying at least one of the following chemical groups: amine, carboxylate, phosphate, sulfate, sulfonate, or nonionic polymer type: polyoxyethylenes, sugars, polysaccharides, dextran, starch.
    According to another variant of the process for manufacturing the fluid for the engine depollution according to the invention, the step b) of functionalization of the particles of oxides or of oxyhydroxides or of metal carbonates is carried out using organic molecules chosen from the list citric acid, trisodium citrate, gluconic acid, dimercaptosuccinic acid, phosphocholine, sodium salt of 4,5-dihydroxy-1,3-benzenesulphonic acid (Tiron), polysulfobetaine, poly (sulfobetaine methacrylate), poly (Sulfobetaine methacrylamide), dextran, carboxymethylated dextran, alginate, chitosan, polyvinyl alcohol (PVA), polyvinylpyrrolidone, polyethylene glycol, polyacrylic acid, sodium polyacrylate, poly (methacrylic acid), sodium polymethacrylate, polymethacrylamide, polyacrylamide, ethylcellulose, polyethylene oxide, polyethyleneimine, polycoprolactone.
    According to another variant of the process for manufacturing the fluid for the engine depollution according to the invention, the step b) of functionalization of the particles of oxides or of oxyhydroxides or of metal carbonates is carried out using molecules of the surfactant type selected from the following list: quaternary ammonium, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, cetyltrimethylammonium bromide, oleic acid, sodium oleate, glycolipids, sophorolipids, sodium bis (2-ethylhexyl) sulfosuccinate.
    According to another variant of the process for manufacturing the fluid for the engine depollution according to the invention, the steps a) of synthesis of the particles of oxides or of oxyhydroxides or of metal carbonates, and b) of functionalization of the oxide particles or oxyhydroxides or metal carbonates are carried out simultaneously in step a '). In this case, the following steps of the manufacturing process becomes the following: • a) synthesis of particles of oxides or oxyhydroxides or of metal carbonates and simultaneous functionalization of these particles, • c) purification of suspensions of particles of d the oxides or oxyhydroxides or metal carbonates synthesized, this purification is carried out by at least one of the following processes, applied alone or in combination: filtration, filtration-washing, rinsing, dialysis, d) dispersion of the particles of oxides or of oxyhydroxides or of functionalized metal carbonates in an aqueous solution containing at least one reducing agent or at least one NOx reducing agent precursor according to one of the following modes: mechanical stirring with the aid of an agitator equipped with either a propeller shaft comprising a number of blades, or any other equipment known to provide effective agitation ace of the suspension, stirring with a high shear homogenizer-disperser (such as, for example, an Ultra-Turrax ™) o stirring with a colloid mill • e) dispersion using an ultrasonic probe L step e) is carried out either as a function of the result and the efficiency obtained at the end of the mechanical dispersion step of step d) (in this case this step e) is optional), or instead of the mechanical stirring step of step d).
    According to another variant of the process for manufacturing the fluid for the engine depollution, the step b) of functionalization of the particles of oxides or of oxyhydroxides or of metal carbonates is carried out by coating, that is to say by deposition of a thin layer of a material whose isoelectric point (PIE) is either greater than 10.5 or less than 8, and preferably greater than 12, or less than 7. This coating makes it possible to stabilize the particles of oxides or oxyhydroxides or metal carbonates in the aqueous solution containing at least one reducing agent or at least one precursor of a NOx reducing agent.
    According to a particular variant of the process for manufacturing the fluid for the engine depollution, when the metal particles are particles of oxides or of oxyhydroxides or of iron carbonates, in the functionalization step, the particles of oxides of iron by a thin layer of silica, or a thin layer of gadolinium, or a thin layer of gold, or any other metal oxide whose PIE is either greater than 10.5 or less than 8, and preferably greater than 12 less than 7. Step a) of synthesis of the iron oxide particles can be carried out by "physical" methods which consist of vacuum synthesis (steam condensation method, thermal evaporation method, ...) or chemicals that concern syntheses in liquid media. Preferably, the iron oxide particles are synthesized chemically: coprecipitation of iron salts, sol-gel route, sonochemical route, microemulsion synthesis, or hydrothermal synthesis.
    Preferably, the iron oxide particles are obtained by coprecipitation of ferrous and ferric ions with a strong base.
    In the variant, in which the synthesis step a) and the functionalization step b) particles of oxides or oxyhydroxides are produced simultaneously, said single step a ') is carried out by alkaline coprecipitation of ferric ions. and ferrous in the presence of dextran.
    Finally, the present invention also relates to the use of the engine depollution fluid in a diesel-type internal combustion engine, the injection of said fluid being carried out upstream of the exhaust gas treatment systems SCR and FAP, (or unique processing system when the latter two are grouped into a single module), and being operated regularly according to the operating conditions of the engine.
    DETAILED DESCRIPTION OF THE INVENTION The invention consists of a multifunctional fluid for the depollution of exhaust gases from an internal combustion engine. The multifunctional fluid according to the invention promotes either the continuous regeneration of the particulate filter or the combustion of soot during the active regeneration phases of the FAP, or allows a combination of these two advantages.
    This fluid incorporates a catalytic additive for regeneration of the particulate filter to an aqueous solution containing at least one reducing agent or at least one NOx reducing agent precursor.
    The fluid according to the invention is in the form of a stable dispersion of metal colloidal particles in an aqueous solution containing at least one reducing agent or at least one NOx reducing agent precursor.
    By the stable term, it is meant that there is no phase separation over time.
    More precisely, the colloidal particles do not aggregate in such a way as to induce sedimentation of the aggregates produced over time. The colloidal dispersion according to the present invention is therefore stable over time.
    More specifically, the fluid for the depollution of heat engines, in particular diesel, according to the invention, is in the form of a stable suspension comprising colloidal particles of one or more metal oxides or oxyhydroxides or metal carbonates dispersed in a solution. aqueous composition containing at least one reducing agent or at least one NOx reducing agent precursor, the metals of the oxides or oxyhydroxides or metal carbonates being chosen from the following metals list: Fe, Cu, Ni, Co, Zn, Mn, Ti, V, Sr, Pt, Ce, Ca, Li, Na, Nb, and preferentially in the following sub-list: Fe, Cu, Ce, Sr.
    The term "iron oxide particles" is understood to mean more particularly the following oxidized forms being understood that this list is not limiting: • Iron oxide is in various forms for which the oxidation state of iron is different :
    Iron II: FeO wustite,
    Iron ΙΠ: hematite a-Fe203, maghemite y-Fc2C> 3,
    Iron II / Iron ΠΙ: magnetite Fe304 • Amorphous iron oxides can also be synthesized and are suitable for the application according to the invention. • Iron oxyhydroxides:
    Fe ΙΠ: goethite a-FeO (OH), lepidocrocite y-FeO (OH), feroxyhyte δ-FeO (OH), akaganite P-FeO (OH), ferrihydrite FesOg ^ FLO, bemalite Fe ( OH) 3,
    Iron II: Fe (OH) 2 • Iron carbonates:
    Siderite FeCCL Ankerite Ca (Fe, Mg, Mn) (CO3) 2
    Carbonated green rust Fe6 (0H) i2C03-2H20
    Chukanovite Fe2 (0H) 2CO3
    In the context of the present invention, all the forms of oxides and oxyhydroxides or iron carbonates mentioned above are suitable, whether these materials are of mineral or synthetic origin. Likewise, ferrite particles, an iron oxide with a spinel structure of the MFe204 type where M denotes a divalent metal ion such as Fe2 +, Ni2 +, Co2 +, are perfectly suitable for the intended application.
    The stability of colloidal dispersions is driven by the forces exerted between particles. These forces are: o Van der Waals forces that are always attractive, o Electrostatic forces: These forces exist when the colloidal particles are electrically charged. The electrical charges of the colloidal particles may be due to isomorphic substitutions in the crystallographic structure of the colloidal particles or due to the presence of ionizable groups on the surface of the particles (as in the case of oxides and oxyhydroxides or iron carbonates and others metals). These forces can be repulsive, attractive or miles depending on the physico-chemical conditions such as the pH of the aqueous solution, the concentration and the nature of the salts in solution.
    For example, in the case of metal oxides, depending on the pH of the aqueous medium, the ionizable groups on the surface of the particles can lead to the existence of positive or negative charges. There is a pH at which the electrical charges (positive and negative) present on the surface compensate: the electrostatic forces then become miles. In this specific case, the density of electrical charges being too low, or even zero, the stability of the dispersions of the colloidal oxide particles is no longer assured if there are only the Van der Waals forces. o steric repulsion forces which are repulsive interparticle forces. These forces exist when molecules (such as, for example, dextran molecules, polymers in general) have been grafted or adsorbed on the surface of the particles.
    Generally, when it comes to the preparation of the pollution control fluid with colloidal particles of a material having an isoelectric point greater than 12 or less than 7, the particles can be directly dispersed in an aqueous solution. whose pH is between 9 and 10 and containing at least one reducing agent or at least one NOx reducing agent precursor. In one variant of the invention, the colloidal particles can be directly dispersed in an AdBlue® solution. It is also possible to use the routes described above for oxides and oxyhydroxides or iron carbonates (organic functionalization or by coating with a layer of silica or another metal oxide).
    In the case of iron oxides such as hematite, maghemite, the isoelectric point (abbreviated as PIE), ie the pH corresponding to a zero electrical charge, is between 7 and 8. that the dispersions of iron oxide particles are stable with respect to aggregation and sedimentation, the particles must be dispersed in an aqueous solution whose pH is sufficiently far from the isoelectric point so that that the resulting electrostatic forces can ensure a good dispersion of the particles by preventing aggregation of these particles. Thus, it is commonly accepted that, in order to have stable colloidal particle dispersions, it is necessary for the pH to be lower than the PIE of the material decreased by 2 pH units, or the pH to be greater than the PIE of the material increased by 2 units pH.
    In the case of the dispersions of colloidal particles of iron oxides mentioned above, it is therefore necessary to disperse the particles in aqueous fluids with pH of less than 5 or greater than 10.
    The present invention consists in a stable dispersion of the colloidal particles of iron oxides in an aqueous solvent whose pH is between 9 and 10, and more particularly in dispersing, for example, particles of iron oxides in a solution of AdBlue®. It is therefore necessary to find means (s) to avoid aggregation of the iron oxide particles.
    Among the solutions that make it possible to avoid the aggregation of particles, the colloidal particles can be functionalized, either by grafting on their surface organic molecules ensuring repulsion of origin, whether electrostatic, steric, or electro-steric between the particles, or by coating them with a thin layer of a material whose isoelectric point (IEP) is sufficiently far from the pH range between 9 and 10.
    Functionalization of the colloidal iron particles in order to prepare stable suspensions in the target pH range can be achieved in different ways: • In a first step, it is possible to synthesize iron oxide particles. Once the synthesis is completed, the particles are functionalized or coated in a second step. • Iron oxide particles can be synthesized and functionalized during the same step. • Suspensions of iron oxide particles can be prepared from powders which are dispersed in aqueous solutions in a pH range for which the surface groups are ionized. In a second step, organic molecules are adsorbed so as to generate repulsions of electrostatic or steric or electro-steric origin between the particles or the particles of a material such as silica are coated in such a way that the particles are stable for pH values between 9 and 10.
    In the options in which the preparation of the stable suspensions involves a step of synthesis of the iron oxide particles, there are different ways of synthesizing iron oxide particles described in the literature: For example, the synthesis of particles may be mentioned. iron oxide according to the Massart process: This synthesis consists in coprecipitating iron II and iron ΙΠ under stoichiometric conditions, this coprecipitation taking place in an acid medium. Typically, in 170 ml of a solution of 1.5 M hydrochloric acid in which 31.41 g of FeCl 2 · 4H 2 O has been dissolved, 85.4 g of (2 FeCl 3 · 6H 2 O) are added. The particles obtained are aggregates of magnetite particles (FesO 2 O. These magnetite particles can be transformed into maghemite particles (y-Fc 2 O 0 by oxidation, for which decantation is carried out on a magnetic plate in a solution of nitric acid. 2M The cationic flocculate of surface-oxidized magnetite is decanted on a magnetic plate and then redispersed with stirring for 30 minutes in a 0.33 M solution of hydrated iron nitrate heated to 100 ° C. In this way, particles are obtained. maghemite which can be either redispersed in an acid medium (for example, a nitric acid solution) or in a basic medium (for example, a potassium hydroxide solution).
    The suspensions of the particles obtained by this synthesis are stable for pH lower than 4 or for pH greater than 10. To obtain suspensions of such perfectly stable particles for pH of between 7 and 11, it is necessary to adsorb to the particle surface either molecules that induce repulsive steric forces, or molecules that carry ionized groups at pH between 7 and 11 generating either electrostatic or electrostatic repulsive forces. For example, trisodium citrate molecules with pKa of 2.8, 4.3 and 5.7 can be adsorbed on the surface of maghemite particles. Thus, for pH greater than 7, the carboxylic functions of trisodium citrate carry three negative charges thus ensuring an electrostatic repulsion between the maghemite particles, which prevents their aggregation. • It is also possible to synthesize iron oxide particles directly functionalized by a macromolecule. An example of such a synthesis is that described by Molday and Mackenzie in an article published in 1982 (whose complete reference is: Molday RS, MacKenzie D., Immunospecifies ferromagnetic iron-dextran reagents for labeling and magnetic separation of cells, J. Immunol Methods, 1982). This synthesis consists in coprecipitating ferric iron chloride and ferrous iron chloride (in a weight ratio of 2.4) in a 50% solution of dextran. During stirring, a base such as ammonia solution (concentration 7.5% v / v) is added, the whole being heated in a temperature range of 60 to 65 ° C. This type of synthesis makes it possible to obtain colloidal magnetite particles stabilized by dextran-induced steric repulsions adsorbed on the surface of the particles.
    Among the processes for obtaining stable dispersions of oxides or oxyhydroxides or iron carbonates (or, generally, oxides or oxidydroxides or metal carbonates) at pH values between 9 and 10, also include those which consists of coating particles with a thin layer of a material whose isoelectric point is sufficiently far from the pH range between 9 and 10. The coating may be made of silica, gold or a latex.
    According to the invention, any type of synthesis of particles of iron oxides or oxyhydroxides or iron carbonates described in the literature is suitable. The synthesis may include a step of functionalizing the iron oxide particles or oxyhydroxides or iron carbonates so that these particles do not aggregate, and therefore do not sediment over time, in an aqueous solution whose pH is between 7 and 11, preferably between 8.5 and 10.5.
    The functionalization of the particles of oxides or of oxyhydroxides or of metal carbonates can be carried out after the synthesis or the redispersion of the powder of the particles by adsorbing different molecules. Functionalization of the particles of oxides or of oxyhydroxides or of metal carbonates is carried out by using ionic polymer-type organic molecules bearing at least one of the following chemical groups: amine, carboxylate, phosphate, sulphate, sulphonate, or of the type nonionic polymers: polyoxyethylenes, sugars, polysaccharides, dextran, starch.
    According to another variant of the process for manufacturing the fluid for the engine depollution according to the invention, the functionalization of the particles of oxides or of oxyhydroxides or of metal carbonates is carried out by using organic molecules chosen from the following list: citric acid, trisodium citrate, gluconic acid, dimercaptosuccinic acid, phosphocholine, sodium salt of 4,5-dihydroxy-1,3-benzenesulphonic acid (Tiron), polysulfobetaine, poly (sulfobetaine methacrylate), poly (sulfobetaine methacrylamide) , dextran, carboxymethylated dextran, alginate, chitosan, polyvinyl alcohol (PVA), polyvinylpyrrolidone, polyethylene glycol, polyacrylic acid, sodium polyacrylate, poly (methacrylic acid), sodium polymethacrylate, polymethacrylamide, polyacrylamide, ethylcellulose, poly (oxide) ethylene), polyethyleneimine, polycoprolactone.
    According to another variant of the process for manufacturing the fluid for the engine depollution according to the invention, the functionalization of the particles of oxides or of oxyhydroxides or of metal carbonates is carried out by using molecules of the surfactant type chosen from the following list : quaternary ammonium, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, cetyltrimethylammonium bromide, oleic acid, sodium oleate, glycolipids, sophorolipids, sodium bis (2-ethylhexyl) sulfosuccinate.
    The oxides or oxyhydroxides or metal carbonates used in the fluid according to the invention may be oxide particles or oxyhydroxides or cerium carbonates. In this case, the process for manufacturing the fluid for the engine depollution consists of the following sequence of steps: a) synthesis of the colloidal particles of oxide or of oxyhydroxides or cerium carbonates, b) functionalization of the particles of cerium oxide or oxyhydroxides or carbonates by organic molecules to stabilize these particles in the aqueous solution containing at least one reducing agent or at least one NOx reducing agent precursor, • c) purification of the suspensions of particles of oxide or oxyhydroxides or cerium carbonates synthesized, this purification is carried out by at least one of the following methods, applied alone or in combination: filtration, or filtration-washing, or rinsing, or dialysis suspensions of particles of oxides or oxyhydroxides or cerium carbonates, • d) dispersion of oxide particles or oxyhydroxides or cerium carbonates in one of the following modes: o mechanical agitation using an agitator equipped with either a propeller shaft with a number of blades, or any other equipment known to provide effective stirring of the slurry, stirring with a high shear homogenizer-disperser (such as, for example, an Ultra-Turrax ™), stirring with a colloid mill, and e) dispersion using an ultrahigh temperature probe. Step e) is either performed according to the result and efficiency obtained at the end of the mechanical dispersion step of step d) (in this case this step e) is optional) is carried out at the place of the mechanical stirring step of step d).
    Preferably, the functionalization step b) oxide particles or oxyhydroxides or cerium carbonates is carried out using organic molecules that induce either steric repulsions, or electrostatic repulsions, or electrostatic repulsions, these repulsions preventing particles of oxide or oxyhydroxides or cerium carbonates from aggregating.
    Also preferably, the step of functionalization b) particles of oxide or oxyhydroxides or cerium carbonates is carried out using organic molecules chosen from the following list: citric acid, trisodium citrate, sodium salt of 4,5-dihydroxy-1,3-benzenesulphonic acid (Tiron), polyethylene glycol, polyethylene glycol phosphonate, polyacrylic acid, sodium polyacrylate, poly (methacrylic acid), sodium polymethacrylate, polymethacrylamide, polyacrylamide poly (ethylene oxide). Step b) of functionalization of the particles of oxide or oxyhydroxides or cerium carbonates can also be carried out from surfactant-type molecules which are chosen from the following list: quaternary ammonium, tetramethylammonium hydroxide, hydroxide tetraethylammonium, tetrapropylammonium hydroxide, cetyltrimethylammonium bromide, sodium bis (2-ethylhexyl) sulfosuccinate.
    With regard to step a) of synthesis, the cerium oxide particles can be synthesized according to the method described in Patent Application No. 2,596,380 of Chane-Ching and Le Loarer.
    EXAMPLES ACCORDING TO THE INVENTION
    The following examples show different embodiments of the product according to the invention and the advantages of the product according to the invention. The two examples given in the case of iron oxides do not constitute a limitation of the present invention to said iron oxides.
    Example 1 Dispersion of Fe 2 LC in Adblue®
    We begin by characterizing the suspension of FesCL at 5% w / w stabilized with sodium citrate. The addition of sodium citrate makes it possible to have a stable suspension at basic pH: the pH of the FesCL suspension is equal to 8.1. For size measurement, we diluted a portion of the stock suspension in a basic solution to have an iron equivalent concentration of 500 ppm; the pH of this diluted suspension is 9.
    Particle diameter measurement was performed by dynamic light scattering (DDL). The particle size is monomodal and the average particle diameter of Fe3C> 4 is 45 nm.
    Next, we dilute the FesCL suspension in a volume of Adblue® so that the final iron concentration of the suspension is equal to 350 ppm.
    The pH of the suspension of Fe304 particles in Adblue® is 9.5.
    The stability of the suspension of Fe3C> 4 in Adblue® is verified by a measurement of turbidimetry of the suspension. The measurement consists of following the temporal evolution of the transmission of a light beam through a suspension of particles over the entire height of the sample. This measurement is sufficient to detect instability of a colloidal suspension (for example, sedimentation of particles). This measurement is done using a commercial device named Turbiscan®. When this measurement is carried out on the suspension of Fe304 particles dispersed in Adblue, it is found that the profile of the intensity transmitted through the glass tube containing the suspension is flat: the value of the transmitted light intensity is constant over the entire height of the tube indicating that there was no sedimentation during this period.
    The particle size of Fe304 dispersed in Adblue® is measured by DDL.
    The distribution of FcXL particles in Adblue® is still monomodal.
    The average diameter is 53.5 nm. It can be seen that the Fe304 particles remain nanometric in size and therefore can not sediment. This observation is in agreement with the measurement made at Turbiscan which shows a stability of the suspension. This example demonstrates that it is possible to disperse iron oxide particles (Fe3O4) in Adblue® and to obtain a stable suspension with time.
    Example 2 Dispersion of Fe3Q3 in a solution of Adblue®
    We characterize the suspension of Fe203 at 3% w / w stabilized with sodium citrate: the addition of sodium citrate makes it possible to have a stable suspension at basic pH.
    The pH of the Fe 2 O 3 suspension is 8.4.
    For size measurement, we dilute a portion of the stock suspension in a basic solution to have an iron equivalent concentration of 500 ppm; the pH of this diluted suspension is 8.7. Particle diameter is measured by dynamic light scattering (DDL). The particle size is monomodal and the average particle diameter of Fe203 is 53 nanometers.
    Next, we dilute the Fe 2 O 3 suspension in one volume of Adblue® so that the final iron concentration of the suspension is 350 ppm. The pH of the suspension in Adblue® is 9.
    The size of Fe203 particles dispersed in Adblue® was measured by DDL.
    The distribution of Fe203 particles in Adblue® remains monomodal. The average diameter is 78 nm. It is found that the particles of Fe203 dispersed in Adblue® remain of nanometric size and therefore can not sediment. This example demonstrates that it is possible to disperse Iron Oxide Particles (Fc203) in Adblue® and to obtain a stable suspension.
    权利要求:
    Claims (16)
    [1" id="c-fr-0001]
    1) Fluid for the depollution of thermal engines, including diesel, to perform both the selective catalytic reduction of nitrogen oxides contained in the exhaust gas, and the aid for the regeneration of the particulate filter by catalytic combustion of soot particles deposited in the particulate filter (so-called FAP regeneration aid function), said fluid being in the form of a stable suspension comprising colloidal particles of one or more oxides or oxyhydroxides metal or metal carbonates dispersed in an aqueous solution containing at least one reducing agent or at least one NOx reducing agent precursor, the metals of the oxides or oxyhydroxides or metal carbonates being chosen from the following list of metals: Fe, Cu , Ni, Co, Zn, Mn, Ti, V, Sr, Pt, Ce, Ca, Li, Na, Nb and preferentially in the following sub-list: Fe, Cu, C e, Sr.
    [0002]
    2) Fluid for the depollution of heat engines, especially diesel, according to claim 1, in which the iron oxides are chosen from the following list, taken alone or as a mixture: wustite FeO, hematite a-Fe203, maghemite y-FeiCF, magnetite.
    [0003]
    3) A fluid for the depollution of thermal engines, in particular diesel, according to claim 1, in which the iron oxyhydroxides, taken alone or as a mixture, are chosen from the following list: goethite a-FeO (OH), lepidocrocite y- FeO (OH), δ-FeO (OH) feroxyhyte, P-FeO (OH) akaganite, FcsOxAfFO ferrihydrite, Fe (OH) 3 bemalite, Fe (OH) 2 ferrous hydroxide
    [0004]
    4) Fluid for the depollution of heat engines, especially diesel, according to claims 1 to 3, wherein at least one of the reducing compounds or at least one of the precursors of a reducing agent in aqueous solution is selected from urea, ammonia, formamide, and ammonium salts, especially ammonium formate, ammonium carbamate, guanidine salts, especially guanidinium formate.
    [0005]
    5) Fluid for the depollution of heat engines, particularly diesel, according to claims 1 to 4, wherein the aqueous solution containing a reducing compound, or precursor of a reducing agent, is urea at 32.5 ± 0, 7% by mass in solution in pure water, and which meets the specifications of ISO 22241-1.
    [0006]
    6) A fluid for the depollution of thermal engines, especially diesel, according to claim 5, wherein the aqueous solution containing a NOx reducing compound is a solution of Adblue®.
    [0007]
    7) Fluid for the depollution of heat engines, particularly diesel, according to claims 1 to 6, wherein the concentration of oxides or metal oxyhydroxides or metal carbonates is such that the concentration of metal ions in the solution of the reducing compound or precursor d a reducing agent is from 10 to 10,000 ppm, preferably from 10 to 5,000 ppm, and preferably from 10 to 2,000 ppm
    [0008]
    8) Fluid for the depollution of heat engines, especially diesel, according to claims 1 to 7, wherein the particles of oxides or oxyhydroxides or metal carbonates are functionalized by at least one organic molecule or by deposit (also called coating) a thin layer of a material whose isoelectric point is either greater than 10.5 or less than 8, and preferably greater than 12, or less than 7.
    [0009]
    9) A method of manufacturing the fluid for the engine depollution according to claims 1 to 8, consisting of the following sequence of steps: a) synthesis of particles of oxides or oxyhydroxides or metal carbonates, b) functionalization of the particles of oxides or oxyhydroxides or metal carbonates by organic molecules or by coating to stabilize these particles in the aqueous solution containing at least one reducing agent or at least one precursor of a NOx reducing agent, • c) purification by filtration, or filtration-washing, or rinsing, or dialysis, processes applied alone or in combination, suspensions of particles of oxides or oxyhydroxides or metal carbonates, • d) dispersion of particles of oxides or oxyhydroxides or metal carbonates functionalized in AdBlue® according to one of the following modes: o mechanical stirring using a stirrer equipped with a propeller shaft comprising a number of blades, or any other equipment known to provide effective stirring of the suspension, stirring with a high shear homogenizer-disperser or stirring with a colloid mill. using an ultrasonic probe, step e) being performed according to the result and the efficiency obtained at the end of the mechanical dispersion step of step d) (in this case case this step e) is optional), is performed in place of the mechanical stirring step of step d).
    [0010]
    10) A process for manufacturing the fluid for the engine depollution according to claim 9, wherein the step b) of functionalization of the particles of oxides or oxyhydroxides or metal carbonates is carried out using organic molecules of ionic polymer type carrying at least one of the following chemical groups: amine, carboxylate, phosphate, sulfate, sulfonate, or nonionic polymer type: polyoxyethylenes, sugars, polysaccharides, dextran, starch.
    [0011]
    11) A process for manufacturing the fluid for the engine depollution according to claim 9, wherein the step b) of functionalization of the particles of oxides or oxyhydroxides or metal carbonates is carried out using organic molecules chosen from the following list : citric acid, trisodium citrate, gluconic acid, dimercaptosuccinic acid, phosphocholine, sodium salt of 4,5-dihydroxy-1,3-benzenesulphonic acid (Tiron), polysulfobetaine, poly (sulfobetaine methacrylate), poly ( sulfobetaine methacrylamide), dextran, dextran carboxymethyl, alginate, chitosan, polyvinyl alcohol (PVA), polyvinylpyrrolidone, polyethylene glycol, polyacrylic acid, sodium polyacrylate, poly (methacrylic acid), sodium polymethacrylate, polymethacrylamide, polyacrylamide, ethylcellulose , polyethylene oxide, polyethyleneimine, polycoprolactone.
    [0012]
    12) A method of manufacturing the fluid for the engine depollution according to claim 9, wherein the step b) of functionalization of the oxide particles or oxyhydroxides or metal carbonates is carried out using selected surfactant-type molecules in the following list: quaternary ammonium, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, cetyltrimethylammonium bromide, oleic acid, sodium oleate, glycolipids, sophorolipids, sodium bis (2-ethylhexyl) sulfosuccinate.
    [0013]
    13) A method of manufacturing the fluid for the engine depollution according to claim 9, wherein the steps a) of synthesis of particles of oxides or oxyhydroxides or metal carbonates, and b) functionalization of the oxide particles or d Oxyhydroxides or metal carbonates are carried out simultaneously.
    [0014]
    14) A method of manufacturing the fluid for the engine depollution according to claim 9, wherein the step b) of functionalization of the particles of oxides or oxyhydroxides or metal carbonates is carried out by coating, that is to say depositing a thin layer of a material whose isoelectric point (PIE) is either greater than 10.5 or less than 8, and preferably greater than 12, or less than 7.
    [0015]
    15) A process for manufacturing the fluid for the engine depollution according to claim 14, wherein, when the colloidal particles are particles of oxides or oxyhydroxides or iron carbonates, the functionalization step b) is carried out by coating said particles of oxides or oxyhydroxides or iron carbonates by a thin layer of silica, or a thin layer of gadolinium, or a thin layer of gold, or any other metal oxide whose PIE is greater than 10 , 5 is less than 8, and preferably greater than 12 or less than 7.
    [0016]
    16) Use of the engine pollution control fluid according to one of claims 1 to 8, in a diesel-type internal combustion engine, the injection of said fluid being carried out upstream of the exhaust gas treatment systems SCR and FAP, and being operated regularly depending on the operating conditions of the engine.
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    同族专利:
    公开号 | 公开日
    US10850233B2|2020-12-01|
    CN108602015A|2018-09-28|
    FR3043568B1|2021-01-29|
    KR20180081130A|2018-07-13|
    CN108602015B|2021-10-29|
    US20180304198A1|2018-10-25|
    EP3374064A1|2018-09-19|
    EP3374064B1|2020-07-29|
    WO2017080779A1|2017-05-18|
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    法律状态:
    2016-11-21| PLFP| Fee payment|Year of fee payment: 2 |
    2017-05-19| PLSC| Publication of the preliminary search report|Effective date: 20170519 |
    2017-11-28| PLFP| Fee payment|Year of fee payment: 3 |
    2019-11-28| PLFP| Fee payment|Year of fee payment: 5 |
    2020-11-26| PLFP| Fee payment|Year of fee payment: 6 |
    2021-11-26| PLFP| Fee payment|Year of fee payment: 7 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1560906A|FR3043568B1|2015-11-13|2015-11-13|FLUID FOR DEPOLLUTION OF THERMAL ENGINES USING STABLE SUSPENSIONS OF METAL COLLOIDAL PARTICLES AND METHODS OF PREPARATION OF SUCH FLUID|FR1560906A| FR3043568B1|2015-11-13|2015-11-13|FLUID FOR DEPOLLUTION OF THERMAL ENGINES USING STABLE SUSPENSIONS OF METAL COLLOIDAL PARTICLES AND METHODS OF PREPARATION OF SUCH FLUID|
    US15/770,801| US10850233B2|2015-11-13|2016-10-20|Fluid for purifying heat engines using stable suspensions of metal colloidal particles, and methods for preparing said fluid|
    CN201680066546.4A| CN108602015B|2015-11-13|2016-10-20|Fluid for purifying a heat engine using a stable suspension of metal colloidal particles, and method for manufacturing said fluid|
    PCT/EP2016/075198| WO2017080779A1|2015-11-13|2016-10-20|Fluid for purifying heat engines using stable suspensions of metal colloidal particles and methods for preparing said fluid|
    EP16784199.8A| EP3374064B1|2015-11-13|2016-10-20|Fluid for purifying heat engines using stable suspensions of metal colloidal particles and methods for preparing said fluid|
    KR1020187016409A| KR20180081130A|2015-11-13|2016-10-20|Fluid for purifying a heat engine using a stable suspension of metal colloid particles and method for producing said fluid|
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