Aqueous composition having improved properties for the treatment of exhaust gases
AssigneeTotalenergies Onetech
InventorVeronica Castillo
Life of this patent
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Abstract
The present invention relates to a paraffin-free aqueous composition comprising: at least one nitrogen oxide NOx reducing agent and/or at least one precursor of such an agent, and at least one additive selected from polyoxyethylenated monoesters of fatty acids including 12 to 22 carbon atoms and sorbitan, at a total content of 10 to 1,500 ppm by weight relative to the total weight of the composition. Another object of the present invention is the use of such a composition for the treatment of exhaust gases at the outlet of internal combustion engines, as well as a method for treating exhaust gases of an internal combustion engine implementing this composition.
Claims16
An aqueous composition comprising:
- (1) at least one nitrogen oxide reducing agent and/or at least one precursor of such an agent, and
- (2) at least one additive selected from polyoxyethylenated monoesters of fatty acids comprising from 12 to 22 carbon atoms and of sorbitan, at a total content from 10 to 1,500 ppm by weight relative to the total weight of the composition,
- this composition containing no paraffins.
The composition according to the preceding claim, characterised in that the reducing agent or the precursor of the reducing agent (1) is selected from the list consisting of urea, ammonia, formamide, ammonium salts, and guanidine salts;
- and preferably from the list consisting of urea and ammonia;
- and more preferably the precursor of the reducing agent is urea.
The composition according to any one of the preceding claims, characterised in that the composition contains urea, at a content ranging from 25% to 42% by weight, preferably from 30% to 40% by weight, more preferably from 31 to 35% by weight and better still from 32% to 33% by weight, relative to the total weight of the composition;
- and still more preferably 32.5±0.7% by weight, relative to the total weight of the composition.
The composition according to any one of the preceding claims, characterised in that the fatty acid(s) of said monoesters (2) comprise from 12 to 20 carbon atoms, preferably from 12 to 18 carbon atoms.
The composition according to any one of the preceding claims, characterised in that said monoesters (2) comprise an average number of oxyethylene units (OE units) comprised in the range from 10 to 30, preferably from 15 to 25, and more preferably of 20.
The composition according to the preceding claim, characterised in that the monoester(s) (2) are selected from polyoxyethylene sorbitan monolaurate with 20 OE, polyoxyethylene sorbitan monooleate with 20 OE and mixtures thereof, and preferably the ester (2) is polyoxyethylene sorbitan monolaurate with 20 OE.
The composition according to any one of the preceding claims, characterised in that the monoester(s) (2) is/are present at a total content from 50 to 1,000 ppm by weight, preferably from 200 to 800 ppm by weight, relative to the total weight of the composition.
The composition according to any one of the preceding claims, characterised in that it further comprises one or more anti-foam additive(s), preferably selected from grafted polydimethylsiloxane polymers, and more preferably from copolymers comprising a polydimethylsiloxane backbone with an average number of dimethylsiloxane units comprised in the range from 150 to 300, grafted by polyoxyalkylene chains.
The composition according to the preceding claim, characterised in that the polydimethylsiloxane backbone of said copolymers comprises an average number of dimethylsiloxane units in the range from 180 to 250.
Use of a composition as defined in any one of the preceding claims for the treatment of exhaust gases from on-board or stationary internal combustion engines.
Dependencies are inferred from the claim text.