Fluid for purifying heat engines using stable suspensions of metal colloidal particles, and methods for preparing said fluid

Patent metadata

Field	Value
Publication number	US-10850233-B2
Application number	US-201615770801-A
Country	US
Kind code	B2
Filing date	Oct 20, 2016
Priority date	Nov 13, 2015
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

The present invention describes a fluid which is suitable for the decontamination of heat engines which can carry out both the catalytic reduction of oxides of nitrogen (NOx) contained in exhaust gases and assist in the regeneration of the particulate filter (PF), 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 reducing agent for NOx. The invention also describes several embodiments for the preparation of said fluid.

First claim

The invention claimed is:

1. A fluid for the decontamination of heat engines, in order to be able to carry out the selective catalytic reduction of oxides of nitrogen contained in exhaust gases as well as assisting in the regeneration of the particulate filter by catalytic combustion of particles of soot deposited in the particulate filter (the function termed assistance in the regeneration of PF), said fluid being in the form of a stable suspension comprising colloidal particles of one or more particles of metal oxides or oxyhydroxides or metal carbonates dispersed in an aqueous solution containing at least one reducing agent or at least one precursor of a reducing agent for the NOx, the metals of the metal oxides or oxyhydroxides or carbonates being selected from the following list of metals: Fe, Cu, Ni, Co, Zn, Mn, Ti, V, Sr, Pt, Ce, Ca, Li, Na, Nb, and in which the iron oxyhydroxides, used alone or as a mixture, are selected from the following list: goethite α-FeO(OH), lepidocrocite γ-FeO(OH), feroxyhyte δ-FeO(OH), akaganeite β-FeO(OH), ferrihydrite Fe 5 O 8 -4H 2 O, bernalite Fe(OH) 3 , and ferrous hydroxide Fe(OH) 2 .

2. A fluid for the decontamination of heat engines, in order to be able to carry out the selective catalytic reduction of oxides of nitrogen contained in exhaust gases as well as assisting in the regeneration of the particulate filter by catalytic combustion of particles of soot deposited in the particulate filter (the function termed assistance in the regeneration of PF), said fluid being in the form of a stable suspension comprising colloidal particles of one or more particles of metal oxides or oxyhydroxides or metal carbonates dispersed in an aqueous solution containing at least one reducing agent or at least one precursor of a reducing agent for the NOx, the metals of the metal oxides or oxyhydroxides or carbonates being selected from the following list of metals: Fe, Cu, Ni, Co, Zn, Mn, Ti, V, Sr, Pt, Ce, Ca, Li, Na, Nb, and in which the aqueous solution containing a reducing compound or reducing agent precursor is urea, 32.5±0.7% by weight in solution in purified water and complies with the specifications of the standard ISO 22241-1.

3. The fluid for the decontamination of heat engines, in particular diesel engines, as claimed in claim 2 , in which the aqueous solution containing a NOx reducing compound is a 32.5% by weight solution of urea in purified water.

4. A fluid for the decontamination of heat engines, in order to be able to carry out the selective catalytic reduction of oxides of nitrogen contained in exhaust gases as well as assisting in the regeneration of the particulate filter by catalytic combustion of particles of soot deposited in the particulate filter (the function termed assistance in the regeneration of PF), said fluid being in the form of a stable suspension comprising colloidal particles of one or more particles of metal oxides or oxyhydroxides or metal carbonates dispersed in an aqueous solution containing at least one reducing agent or at least one precursor of a reducing agent for the NOx, the metals of the metal oxides or oxyhydroxides or carbonates being selected from the following list of metals: Fe, Cu, Ni, Co, Zn, Mn, Ti, V, Sr, Pt, Ce, Ca, Li, Na, Nb, and in which the concentration of metal oxides or oxyhydroxides or metal carbonates is such that the concentration of metal ions in the solution of the reducing compound or precursor of a reducing agent is in the range 10 to 10000 ppm.

5. A process for the production of a fluid for engine decontamination in order to be able to carry out the selective catalytic reduction of oxides of nitrogen contained in exhaust gases as well as assisting in the regeneration of the particulate filter by catalytic combustion of particles of soot deposited in the particulate filter (the function termed assistance in the regeneration of PF), the fluid being in the form of a stable suspension comprising colloidal particles of one or more particles of metal oxides or oxyhydroxides or metal carbonates dispersed in an aqueous solution containing at least one reducing agent or at least one precursor of a reducing agent for NOx, the metals of the metal oxides or oxyhydroxides or carbonates being selected from the following list of metals: Fe, Cu, Ni, Co, Zn, Mn, Ti, V, Sr, Pt, Ce, Ca, Li, Na, Nb, comprising the following sequence of steps:
a) synthesis of particles of metal oxides or oxyhydroxides or carbonates,
b) functionalization of the particles of metal oxides or oxyhydroxides or carbonates by organic molecules or by coating in order to stabilize the particles in the aqueous solution containing at least one reducing agent or at least one precursor of a reducing agent for NOx,
c) purification by filtration, or filtration-washing, or rinsing, or dialysis, the processes being applied alone or in combination, of the suspensions of particles of metal oxides or oxyhydroxides or carbonates,
d) dispersion of the functionalized metal oxides or oxyhydroxides or carbonates in 32.5% by weight solution of urea in purified water in accordance with one of the modes below:
mechanical agitation with the aid of an agitator equipped with either a helical screw comprising a certain number of blades, or any other equipment which is known to provide effective stirring of the suspension,
agitation with a high shear homogenizer-disperser,
agitation with a colloidal mill,

e) dispersion with the aid of an ultrasound probe, step e) either being carried out 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 carried out in place of the mechanical agitation step of step d).

6. The process for the production of fluid for engine decontamination as claimed in claim 5 , in which the oxides of iron are selected from the following list, used alone or as a mixture:
wustite FeO, haematite α-Fe 2 O 3 , maghemite γ-Fe 2 O 3 and magnetite.

7. The process for the production of fluid for engine decontamination as claimed in claim 5 , in which 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, in particular ammonium formate, ammonium carbamate, and guanidine salts, in particular guanidinium formate.

8. The process for the production of fluid for engine decontamination as claimed in claim 5 , in which step b) for the functionalization of the particles of metal oxides or oxyhydroxides or carbonates is carried out by using organic ionic polymer type molecules carrying at least one of the following chemical groups:
amine, carboxylate, phosphate, sulfate, sulfonate, or using non-ionic polymer types:
polyoxyethylenes, sugars, polysaccharides, dextran, starch.

9. The process for the production of fluid for engine decontamination as claimed in claim 5 , in which step b) for functionalization of the particles of metal oxides or oxyhydroxides or carbonates is carried out by using organic molecules selected from the following list: citric acid, trisodium citrate, gluconic acid, dimercaptosuccinic acid, phosphocholine, the sodium salt of 4,5-dihydroxy-1,3-benzenedisulfonic acid (Tiron), polysulfobetain, poly(sulfobetain methacrylate), poly(sulfobetain methacrylamide), dextran, carboxymethyl dextran, alginate, chitosan, polyvinyl alcohol (PVA), polyvinylpyrrolidone, polyethylene glycol, poly(acrylic acid), sodium polyacrylate, poly(methacrylic acid), sodium polymethacrylate, polymethacrylamide, polyacrylamide, ethylcellulose, poly(ethylene oxide), polyethyleneimine, polycaprolactone.

10. The process for the production of fluid for engine decontamination as claimed in claim

Assignees

• Ifp Energies Now

Inventors

• Lecolier Eric
• Gateau Patrick
• Zinola Stephane
• Palazzo Nathalie

Classifications

• B01D2251/206

  Ammonium compounds · CPC title

• B01D53/944

  Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts (three-way-catalysts [TWC] B01D53/9445) · CPC title

• B01D53/9409 Primary

  Nitrogen oxides · CPC title

• F01N2610/01

  the substance being catalytic material in liquid form · CPC title

• F01N3/2066

  Selective catalytic reduction [SCR] · CPC title