WO2023002108A1

WO2023002108A1 - Use of a composition of additives for reducing diesel vehicle emissions

Info

Publication number: WO2023002108A1
Application number: PCT/FR2022/051401
Authority: WO
Inventors: Bernard Dequenne
Original assignee: Totalenergies Onetech
Priority date: 2021-07-19
Filing date: 2022-07-12
Publication date: 2023-01-26
Also published as: AU2022314249A1; FR3125298A1; KR20240036033A

Abstract

The present invention relates to the use of a composition of additives for reducing emissions of nitrogen oxides and of at least one type of pollutant selected from carbon monoxide and hydrocarbons which are unburnt during the combustion of a liquid fuel in a compression-ignition internal combustion engine, said composition comprising: (i) one or more additive(s) selected from compounds having at least one alkylphenol group in their structure; and (ii) one or more additives which improve the cetane number, selected from alkyl nitrates, aryl peroxides and alkyl peroxides; wherein the weight ratio of the amount of additive(s) (i) to the amount of additive(s) (ii) is within the range from 1:3 to 3:1. The present invention also relates to a method for reducing emissions of nitrogen oxides and of at least one type of pollutant selected from carbon monoxide and hydrocarbons which are unburnt during the combustion of a liquid fuel in a compression-ignition internal combustion engine which employs this composition of additives.

Description

DESCRIPTION

TITLE: Use of a composition of additives to reduce emissions from Diesel vehicles The present invention relates to the use of a composition of specific additives to reduce the emissions of pollutants from vehicles equipped with compression ignition engines or Diesel engines .

The present invention also relates to a process or a method for reducing pollutant emissions from vehicles equipped with compression ignition engines or diesel engines, implementing this composition of additives in a fuel.

STATE OF THE PRIOR ART

European and global pollution standards applicable to both light and heavy vehicles have imposed increasingly severe constraints on the emission levels of vehicles equipped with compression ignition engines (Diesel engines).

In a manner known per se, because the combustion of a fuel in a reciprocating engine is imperfect, these engines emit during the combustion cycles polluting compounds of different natures. In particular, there are four regulated pollutants: three gases (carbon monoxide, nitrogen oxides and unburned hydrocarbons) and solid particles. Carbon monoxide (CO) is a toxic gas by inhalation which can be fatal at certain concentrations, nitrogen oxides (NOx) are often associated with local urban pollution problems and unburnt hydrocarbons are the result of the incomplete combustion of certain compounds. Solid particulates also come from the incomplete combustion of fuel, starting from carbon-rich compounds (like aromatics) on which other compounds condense to form solid soot. Modern requirements for the reduction and control of these emissions have led engine and vehicle manufacturers to set up post-treatment systems for the exhaust gases leaving the engines. These post-treatment systems include different technologies among which we can distinguish in particular:

- selective catalytic reduction devices known under the name SCR (Selective Catalytic Reduction or selective catalytic reduction in French), which make it possible to reduce the nitrogen oxides NO and NO2 (commonly called NOx) on a catalytic device in which they are brought into contact with a reducing agent,

- "NOx trap" devices (LNT) which act by adsorption of NOx then reduction when the conditions are met (operation in rich mixture);

- exhaust gas recirculation devices known as EGR (Exhaust Gas Recirculation), and

- devices of the particle filter type commonly referred to as FAP. We can also mention the so-called SCRoF (SCR on Filter) or SCRF or SDPF systems which combine, within a single element, the functions of NOx reduction by SCR and particle filtration. These various exhaust gas post-treatment devices can be installed alone or in combination, insofar as they do not always act on the same pollutants present in the exhaust gases.

Thus, solutions to the problem of reducing pollutant emissions from vehicles have essentially been sought from manufacturers. It should however be stressed that the actual emission levels of even the most recent vehicles, subjected to the most stringent new tests following Dieselgate, are not harmed. Similarly, it has been shown that this type of vehicle could still emit high levels of pollutants in certain real driving conditions (very urban) or depending on the type of pollution control system (IFPEN study for the Ministry of Ecological Transition at the end of 2020 on Euro 6D-Time vehicles). The studies also showed that for older vehicles, the actual emission levels could be very widely higher than those expected outside the previous European homologation cycle (NEDC). It may therefore be particularly interesting to lower the actual levels of emissions beyond the treatments carried out in the vehicles. The use of various types of additives in the fuels supplying these engines is also known. These additives are chemical compounds which are incorporated in small quantities into fuels, in order to improve their intrinsic performance. We can cite, for example, cold-resistance additives (aimed at improving the behavior of fuels at low temperatures), deposit-reducing additives (aimed at reducing the fouling effect of fuels in engines during combustion), procetane additives (aimed at increasing the cetane number and therefore the energy performance of fuels), etc. However, additive manufacturers have made very little attempt to solve the problem of controlling polluting emissions. On the contrary, it is generally considered that additives have little or no impact on polluting emissions.

Thus, the publication entitled "The characteristics of performance and exhaust emissions of a diesel engine using a biodiesel with antioxidants", Bioresource Technology 101 (2010), S78-82, reports the results of a study on the effect on the stability to oxidation, engine performance and polluting emissions, of known anti-oxidant additives (in particular compounds with an alkyl-phenol group) in biodiesel-based fuels. The authors conclude that these additives have very little effect on emissions.

Furthermore, pollutants are often treated individually, i.e. a given technology can only reduce one type of pollutant, for example NOx, and not the others (for example carbon monoxide). carbon, particles, unburnt hydrocarbons, etc.). Different technologies must therefore be juxtaposed in order to meet regulatory requirements.

Publication SAE 2000-01-1853, for example, provides information on the CO and HC benefit linked to the use of procetane but reveals a slight increase in NOx. SAE publication 2009-01-2697 studies the impact of the cetane number on a 6.7L Cummins engine and confirms an increase in NOx linked to high cetane numbers (adjusted by the use of procetane). There therefore remains the need to develop complete solutions, which make it possible to treat polluting emissions more globally. These solutions must be compatible with existing solutions. They must be efficient, whatever the engine technology, the actual efficiency of the post-treatment system and/or the nature of the fuel, in particular its origin (petroleum and/or biosourced). These solutions must also not be provided to the detriment of the other expected properties associated with the use of performance additives in high quality fuels (engine cleanliness, anticorrosion, antifoam, etc.), which must be maintained.

OBJECT OF THE INVENTION

The Applicant has now discovered that the use of a particular composition of additives, based on the association of an additive with an alkyl-phenol group with a procetane additive in well-defined proportions, exhibited a significant and unexpected effectiveness on the reduction of polluting emissions from fuels used in diesel engines, and provided an effect of simultaneous reduction of at least two types of pollutants including the four main types of pollutants which are nitrogen oxides (NOx), carbon monoxide ( CO), unburned hydrocarbons and solid particles.

The present invention thus relates to the use, to reduce the emissions of nitrogen oxides and of at least one type of polluting agent chosen from carbon monoxide and unburnt hydrocarbons during the combustion of a fuel liquid in a compression ignition internal combustion engine, of an additive composition comprising:

(i) one or more additives chosen from compounds having in their structure at least one alkyl-phenol group; and (ii) one or more cetane number-improving additives selected from alkyl nitrates, aryl peroxides and alkyl peroxides; wherein the mass ratio of the amount of additive(s) (i) to the amount of additive(s) (ii) is within the range from 1:3 to 3:1.

The incorporation into a diesel engine fuel of this composition of additives makes it possible to obtain a significant reduction in the levels of polluting emissions compared to the same fuel not containing these additives. Particularly unexpectedly, the reduction is obtained simultaneously for several types of pollutants including at least nitrogen oxides, carbon monoxide and/or unburnt hydrocarbons.

According to a preferred embodiment, the invention makes it possible to simultaneously reduce the emissions of nitrogen oxides, carbon monoxide and unburnt hydrocarbons.

According to a particularly preferred embodiment, the invention also makes it possible to reduce the emissions of solid particles.

The composition of additives according to the invention is effective in the various types of fuel intended for diesel engines, also called gas oils, whether they are of petroleum origin or not, including fuels derived wholly or partly from biomass.

It also makes it possible to provide the properties required for a diesel fuel, and to maintain excellent levels of performance in terms of engine and injector cleanliness, cetane number, anti-foam and anti-corrosion performance in particular.

The invention also relates to a process or method for reducing emissions of nitrogen oxides and of at least one type of polluting agent chosen from carbon monoxide and unburnt hydrocarbons during the combustion of a fuel. liquid in a compression ignition internal combustion engine, comprising the addition to said fuel of a composition of additives as defined above.

Other objects, characteristics, aspects and advantages of the invention will appear even more clearly on reading the description and the examples which follow.

In what follows, and unless otherwise indicated, the limits of a range of values are included in this range, in particular in the expressions “included between” and “ranging from ... to ...”.

Furthermore, the expressions “at least one” and “at least” used in the present description are respectively equivalent to the expressions “one or more” and “greater than or equal”. Finally, in a manner known per se, the term CN compound or group designates a compound or a group containing N carbon atoms in its chemical structure.

DETAILED DESCRIPTION

Alkyl phenol compounds:

The invention uses as additive (i) one or more compound(s) having in their structure at least one alkyl-phenol group. This means that this or these compounds have in their formula at least one phenolic ring (i.e. a benzene ring substituted by one or more hydroxy -OH groups) substituted by one or more alkyl groups.

According to a first embodiment, the additive(s) (i) are chosen from the compounds (i)a) comprising one or two phenolic ring(s) substituted by one or more alkyl groups chosen from the groups methyl and t-butyl (or tert-butyl).

These compounds (i) a) can more particularly be chosen from methyl-t-butyl phenols, dimethyl-t-butyl phenols, ethyl-t-butyl phenols, t-butyl phenols, di-t-butyl phenols , tri-t-butyl phenols, di-t-butyl-di-methyl phenols, and mixtures thereof.

Preferred compounds are chosen from 2,6-di-t-butyl-4-methyl phenol (BHT), 4,6-di-tert-butyl-2-methylphenol, t-butyl hydroquinone (TBHQ), 2 ,6 and 2,4 di-t-butyl phenol, 2,4- dimethyl-6-t-butyl phenol, 2,4,6-tri-t-butyl phenol, 2,3,6-trimethyl phenol, 2,4,6- trimethyl phenol, 4,4'-methylene bis (2,6-di-t-butyl phenol) (CAS No. 1 18-82-1), alone or as a mixture.

The particularly preferred compounds are chosen from (di)tert-butyl phenols, methyl-tert-butylphenols and di-methyl-tert-butylphenols, their mixtures, and their pairwise condensation products, such as in particular 2,6-di-t-butyl-4-methyl phenol (BHT), 2,4-dimethyl-6-t-butyl phenol, 2,5-dimethyl-4-t-butyl phenol, 2,6 and 2,4 di-t-butyl phenol, 2,4,6-tri-t-butyl phenol, mixtures thereof, and their two-by-two condensation products.

According to a second embodiment, the additive(s) (i) are chosen from modified alkylphenol-aldehyde resins (i)b) capable of being obtained by Mannich reaction of an alkylphenol-aldehyde condensation resin: with at at least one aldehyde and/or ketone having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms; and at least one hydrocarbon compound having at least one alkylpolyamine group, having between 1 and 30 carbon atoms, preferably between 4 and 30 carbon atoms, said alkylphenol-aldehyde condensation resin itself being capable of being obtained by condensation : at least one alkylphenol substituted by at least one alkyl group, linear or branched, having from 1 to 30 carbon atoms, preferably a mono alkylphenol, with at least one aldehyde and/or one ketone having from 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms.

The alkylphenol-aldehyde condensation resin can be chosen from any resin of this type already known and in particular those described in the documents EP857776, EP1584673. The alkylphenol-aldehyde resins modified according to the invention are advantageously obtained from at least one alkylphenol substituted in the para position. Preferably, nonylphenol is used.

The average number of phenolic nuclei per molecule of nonylphenol-aldehyde resin is advantageously within the range ranging from 6 to 25, preferably from 8 to 17, and more preferably comprised from 9 to 16.

The number of phenolic nuclei can be determined by nuclear magnetic resonance (NMR) or gel permeation chromatography (GPC).

Advantageously, the modified alkylphenol-aldehyde resins are obtained by using the same aldehyde or the same ketone in the two stages of its preparation.

The modified alkylphenol-aldehyde resins can be obtained from at least one aldehyde and/or one ketone chosen from formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, 2-ethyl-hexanal, benzaldehyde and/or 'acetone. Preferably, the modified alkylphenol-aldehyde resin is obtained from at least one aldehyde, preferably from at least formaldehyde (or methanal). Preferably, the modified alkylphenol-aldehyde resins can be obtained from p-nonylphenol, formaldehyde and at least one hydrocarbon compound comprising at least one alkylpolyamine group.

Said hydrocarbon compound can be an alkylpolyamine having at least two primary and/or secondary amine groups. In particular, the alkyl polyamine is advantageously chosen from primary or secondary polyamines substituted by, respectively, one or two alkyl groups comprising, preferably, from 12 to 24 carbon atoms, more preferentially from 12 to 22 carbon atoms.

Preferably, the modified alkylphenol-aldehyde resin is obtained from at least one alkylpolyamine having at least two primary amine groups, preferably three primary amine groups. In particular, the modified alkylphenol-aldehyde resin can advantageously be obtained from at least one alkylpolyamine in which all the amine groups are primary amines.

Preferably, the modified alkylphenol-aldehyde resin is obtained from at least one alkylpolyamine comprising at least a fatty chain having from 12 to 24 carbon atoms, preferably from 12 to 22 carbon atoms.

A particularly preferred alkylpolyamine is tallow dipropylenetriamine. Commercial alkylpolyamines are generally not pure compounds but mixtures. Among the marketed alkylpolyamines which are suitable, mention may in particular be made of the alkylpolyamines with a fatty chain marketed under the names Trinoram®, Duomeen®, Dinoram®, Triameen®, Armeen®, Polyram®, Lilamin® and Cemulcat®.

Mention may be made, by way of preferred example, of Trinoram®S which is a tallow dipropylenetriamine, also known under the name N-(Tallowalkyl)dipropylenetriamine (CAS 61791-57-9).

It is of course possible to combine the two embodiments and to use a combination of compounds (i)a) and (i)b) as described above.

Thus, according to a preferred embodiment, the composition of additives comprises one or more compounds (i) a) comprising one or two phenolic ring(s) substituted by one or more alkyl groups chosen from the groups methyl and t-butyl, and one or more modified alkylphenol-aldehyde resins (i)b).

Additives improving the cetane number:

The invention uses as additives (ii) one or more additives improving the cetane number, also known as procetane additives or cetane booster additives.

The additive(s) (ii) are chosen from alkyl nitrates and aryl or alkyl peroxides.

Among the aryl peroxides, mention may be made in particular of benzyl peroxide. Among the alkyl peroxides, mention may be made of tert-butyl peroxide.

The additive(s) (ii) are preferably chosen from alkyl nitrates, and more preferably those of formula R-NO3 with R a alkyl radical comprising from 2 to 12 carbon atoms, preferably from 4 to 8 carbon atoms.

A particularly preferred additive (ii) is ethyl hexyl nitrate. The composition of additives

The composition of additives used in accordance with the present invention is characterized in that the mass ratio of the quantity of additive(s) (i) to the quantity of additive(s) (ii) is included in the range from 1:3 to 3:1. Preferably, the mass ratio of the amount of additive(s) (i) to the amount of additive(s) (ii) is within the range from 1:2.5 at

2.5:1, preferably from 1:2 to 2:1 and more preferably from 1:1 to

1.5:1. Deposit reducing additives

According to a preferred embodiment, the composition of additives used in accordance with the present invention further comprises one or more detergency additive(s), also called deposit reducing additive(s), different from the compounds (i) having in their structure at least one alkyl-phenol group and additives (ii) improving the cetane number described above, and which can be chosen from the detergency additives for diesel fuels usually employed. The latter are compounds well known to those skilled in the art.

The deposit-reducing additives can be in particular (but not limited to) chosen from the group consisting of amines, succinimides, alkenylsuccinimides, polyalkylamines, polyalkyl polyamines, polyetheramines, quaternary ammonium salts, and triazole derivatives , and more preferably from quaternary ammonium salts, and polyisobutylene mono- or poly-amines (or GDP-amines), more preferably still from polyisobutylene succinimide (substituted or not by a triazole group), or salts of quaternary ammoniums and better still among polyisobutylene succinimides functionalized with a quaternary ammonium group, fatty acid amides functionalized with a quaternary ammonium group and their dimers such as the di-(alkylamido-propyl-quaternary ammonium) compounds described for example in European patent application No. 18306589.5, alkylamidoalkyl betaines with a fatty chain and triazole derivatives. Most particularly preferred are polyisobutylene succinimides functionalized with a quaternary ammonium group and polyisobutylene succinimides functionalized with a triazole group.

Examples of deposit reducing additives are given in the following documents: EP0938535, US2012/010112,

W02012/004300, US4171959 and W02006/135881.

It is also possible to use block copolymers formed from at least one polar unit and one apolar unit, such as for example those described in patent application FR 1761700 in the name of the Applicant.

According to one embodiment, the additive composition comprises at least one deposit-reducing additive consisting of a quaternary ammonium salt, obtained by reaction with a quaternizing agent of a nitrogen compound comprising a tertiary amine function, this compound nitrogen being the product of the reaction of an acylating agent substituted by a hydrocarbon group and of a compound comprising at least one tertiary amine group and at least one group chosen from primary amines, secondary amines and alcohols. Preferably, said nitrogen compound is the reaction product of a succinic acid derivative substituted by a hydrocarbon group, preferably a polyisobutenyl-succinic anhydride, and an alcohol or a primary or secondary amine also comprising a group tertiary amine. Such deposit-reducing additives, as well as preferred combinations of deposit-reducing additives comprising them, are described in particular in patent application WO 2015/124584 in the name of the applicant.

When the additive composition contains one or more deposit-reducing additive(s), preferably the ratio between the total content by weight of compounds (i) having in their structure at least one alkyl-phenol group on the one hand and the total content by weight of deposit-reducing additive(s) (iii) on the other hand ranges from 1:60 to 1:2, preferably from 1:20 to 1: 3.

Preferably, the total content of deposit reducing additive(s) (iii) in the fuel ranges from 5 to 5000 ppm by weight, preferably from 10 to 1000 ppm by weight, and even more preferably from 20 to 500 ppm by weight. ppm by weight, based on the total weight of the fuel.

The other additives The composition of additives may also comprise other additives, in addition to the compound(s) (i) having in their structure at least one alkyl-phenol group, additives (ii) improving the cetane number described above -before the deposit-reducing additive(s) (iii) described above. This or these other additives can be chosen, for example, in a non-limiting manner, from anti-corrosion additives, dispersing additives, demulsifying additives, anti-foaming agents, biocides, reodorants, friction modifiers, additives lubricity or lubricity additives, combustion aid agents (catalytic combustion and soot promoters), cold behavior additives and in particular agents improving the cloud point, the pour point, the TLF (“Filterability limit temperature”), anti-sedimentation agents, anti-wear agents, tracers, solvents/carrier oils and conductivity modifying agents. Among these additives, mention may be made, for example: a) antifoam additives, in particular (but not limited to) chosen from polysiloxanes, oxyalkylated polysiloxanes, and fatty acid amides derived from vegetable or animal oils. Examples of such additives are given in EP861882, EP663000, EP736590; b) Cold flow improver additives (CFI in English “Cold Flow Improver”) chosen from copolymers of ethylene and unsaturated ester, such as ethylene/vinyl acetate (EVA), ethylene/vinyl propionate (EVP) copolymers , ethylene/vinyl ethanoate (EVE), ethylene/methyl methacrylate (EMMA), and ethylene/alkyl fumarate described, for example, in documents US3048479, US3627838, US3790359, US3961961 and EP261957; c) lubricity additives or anti-wear agents, in particular (but not limited to) chosen from the group consisting of fatty acids and their ester or amide derivatives, in particular glycerol monooleate, and derivatives of mono- and polycyclic. Examples of such additives are given in the following documents: EP680506, EP860494, WO98/04656, EP915944, FR2772783, FR2772784; d) cloud point additives, including (but not limited to) selected from the group consisting of long chain olefin/(meth)acrylic ester/maleimide terpolymers, and polymers of fumaric/maleic acid esters. Examples of such additives are given in FR2528051, FR2528051, FR2528423,

PPE 12195, EP172758, EP271385, EP291367; e) polyfunctional cold-operability additives chosen from the group consisting of polymers based on olefin and alkenyl nitrate as described in EP573490; f) anti-corrosion additives such as, for example, dimers of fatty acid esters and aminotriazoles.

These additional additives may be present in an amount ranging that their amount will each be from 5 to 1000 ppm (each), preferably from 50 to 500 ppm by weight, based on the total weight of the fuel.

The composition of additives can advantageously comprise an organic solvent, which can for example be chosen from aromatic hydrocarbon solvents such as the solvent marketed under the name "SOLVESSO", alcohols, ethers and other oxygenated compounds, and paraffinic solvents such as as hexane, pentane or isoparaffins, including hydrotreated vegetable oils known as HVO, alone or as a mixture.

According to a preferred embodiment, the composition of additives comprises at least one solvent chosen from alcohols. So particularly advantageous, the additive composition contains at least one C1 to C8 monoalcohol, and preferably chosen from ethanol and ethyl-2-hexanol. liquid fuel

The use of the composition of additives according to the invention applies to a fuel in liquid form at ambient temperature (20° C.) and atmospheric pressure (1.013.10 ⁵ Pa). This fuel is intended to power a diesel engine. Such a fuel typically comprises at least one liquid hydrocarbon cut from one or more sources chosen from the group consisting of mineral sources, animal, vegetable and synthetic sources.

The fuel is advantageously chosen from hydrocarbon fuels and non-essentially hydrocarbon fuels, and mixtures thereof.

Hydrocarbon fuel means a fuel consisting of one or more compounds consisting solely of carbon and hydrogen. “Non-essentially hydrocarbon fuel” means a fuel consisting of one or more compounds consisting not essentially of carbon and of hydrogen, that is to say which also contain other atoms, in particular oxygen atoms.

Hydrocarbon fuels include in particular middle distillates with a boiling point ranging from 100 to 500°C. These distillates can for example be chosen from distillates obtained by direct distillation of crude hydrocarbons, vacuum distillates, hydrotreated distillates, distillates resulting from catalytic cracking and/or hydrocracking of vacuum distillates, distillates resulting from conversion processes such as ARDS (atmospheric residue desulphurization) and/or visbreaking, distillates resulting from the recovery of Fischer Tropsch cuts, biodiesels such as distillates resulting from BTL (biomass to liquid) conversion ) plant and/or animal biomass and vegetable oils known to those skilled in the art under the name HVO (standing for “hydrotreated vegetable oil”) or HDRD (standing for “hydrogenation-derived renewable diesel”). Hydrocarbon fuels are typically gas oils (also called diesel fuels).

Gas oils include, in particular, all commercially available diesel engine fuel compositions. Mention may be made, by way of representative example, of diesel fuels complying with standard NF EN 590. Fuels which are not essentially hydrocarbon-based include in particular oils and/or esters of vegetable and/or animal oils.

The mixtures of hydrocarbon-based fuel and of non-essentially hydrocarbon-based fuel are typically gas oils of type B _x .

Type B _x diesel oil for Diesel engines means diesel fuel which contains x% (v/v) of vegetable or animal oil esters (including used cooking oils) transformed by a chemical process called transesterification, obtained by reacting this oil with an alcohol to obtain fatty acid esters (FAE). With methanol and ethanol, we obtain, respectively, fatty acid methyl esters (FAME) and fatty acid ethyl esters (FEAG). The letter "B" is followed by a number x greater than zero and less than or equal to 100, which indicates the percentage of EAG contained in the diesel fuel. Thus, a B99 contains 99% of EAG and 1% of middle distillates of fossil origin (mineral source), the B20, 20% of EAG and 80% of middle distillates of fossil origin etc.... We therefore distinguish the type Bo gas oils which do not contain oxygenated compounds, type Bx gas oils which contain x% (v/v) of esters of vegetable oils or fatty acids, most often methyl esters (VOME or FAME), x designating a number ranging from 0 to 100. When the EAG is used alone in engines, the fuel is designated by the term Bioo.

According to a preferred embodiment, the fuel is chosen from gas oils, biodiesels, type B gas oils _x containing x% (v/v) of vegetable or animal oil esters with x a number greater than zero and less or equal to 100, hydrotreated vegetable oils (HVO), and mixtures thereof.

According to a particularly preferred embodiment, the fuel is chosen from type B gas oils _x containing x% (v/v) of vegetable or animal oil esters with x a number greater than zero and less than or equal to 100. The vegetable oil esters are most particularly chosen from fatty acid methyl esters (FAME) and fatty acid ethyl esters (EEAG).

The sulfur content of the fuel is preferably less than or equal to 1000 ppm, preferably less than or equal to 500 ppm, and more preferably less than or equal to 50 ppm, or even less than 10 ppm and advantageously sulfur-free.

Use

The composition of additives according to the invention is used to reduce the emissions of nitrogen oxides as well as carbon monoxide and/or unburned hydrocarbons during the combustion of a liquid fuel in an internal combustion engine at compression ignition. Preferably, the use is aimed at also reducing particulate emissions. By this is meant that the incorporation of the composition of additives according to the invention in the liquid fuel produces an effect of reducing the emissions of nitrogen oxides as well as carbon monoxide and/or unburned hydrocarbons at the outlet. compression ignition engines powered by said fuel, compared to the same fuel not comprising the composition according to the invention. Preferably, the reduction effect is produced for the three types of emissions, namely nitrogen oxides, carbon monoxide and unburnt hydrocarbons. Preferably, the reduction effect is also produced for particulate emissions. According to a first preferred embodiment, the compression ignition engine or diesel engine is a hybrid diesel engine or a direct injection diesel engine, preferably a direct injection diesel engine and in particular a diesel engine with a common injection system. Rail (CRDI in English “Common Rail Direct Injection”).

According to a second preferred embodiment, the compression ignition engine or diesel engine is a marine engine.

Emission levels of nitrogen oxides, carbon monoxide, unburned hydrocarbons and particles are measured in accordance with the methods defined in European regulation ECE-R83.05.

This regulation defines a harmonized test procedure for the approval of vehicles in Europe and the measurement of the different types of emissions. These regulations are defined with reference to a standardized test called WLTP (World harmonized Light duty Test Procedure), which is a globally harmonized test procedure. This test involves measuring the emissions of a standardized vehicle (Euro 6) during a defined test cycle called WLTC (from the English “World harmonized Light duty Test Cycle”), using high-precision emissions analyzers .

The composition of additives is advantageously used in an amount such as:

- the total mass quantity of additives (i) ranges from 10 to 2000 ppm by weight, preferably from 20 to 1000 ppm by weight, more preferably from 50 to

500 ppm by weight and better still from 200 to 400 ppm by weight, relative to the total weight of the fuel;

- the total mass quantity of additives (ii) ranges from 10 to 1500 ppm by weight, preferably from 20 to 1000 ppm by weight, more preferably from 50 to 500 ppm by weight and better still from 150 to 400 ppm by weight, relative to the total weight of the fuel.

The use according to the invention is compatible with existing exhaust gas post-treatment devices, and makes it possible to further reduce the levels of pollutants emitted by vehicles equipped with such devices and/or to extend the service life of this equipment and/or to space out maintenance operations on this equipment.

Thus, according to a particularly advantageous embodiment, the compression ignition engine is equipped with one or more exhaust gas post-treatment devices, preferably chosen from selective catalytic reduction devices known under the name SCR, exhaust gas recirculation devices known under the name EGR, devices of the particulate filter type commonly referred to as FAP, and so-called SCRoF (SCR on Filter ) or SCRF or SDPF which combine, within a single device, the functions of selective catalytic reduction and particle filtration.

Fe process or method

Fe process or method for reducing emissions of nitrogen oxides and of at least one type of polluting agent chosen from carbon monoxide and unburned hydrocarbons during the combustion of a liquid fuel in an internal combustion engine ignition by compression, consists in adding to said fuel composition a composition of additives as described above.

Preferably, the method is a method for reducing emissions of nitrogen oxides, carbon monoxide and unburned hydrocarbons. According to a particularly preferred embodiment, it also reduces the emissions of solid particles.

The additives constituting the additive composition can be incorporated into the liquid fuel within a refinery and/or be incorporated downstream of the refinery, either separately or in a mixture, and in this case optionally in dispersion in an organic solvent, in particular in the form of a package of additives.

The combustion of the fuel thus additived in the internal combustion engine produces an effect on the reduction of emissions of nitrogen oxides, carbon monoxide and particles measured according to the methods described above in the context of use. A simultaneous reduction of the different types of pollutants is thus obtained.

Fa description above of the composition of additives, fuels and their use in fuels supplying a compression ignition engine fully applies to the process or method according to the invention.

The examples below are given by way of illustration of the invention, and cannot be interpreted in such a way as to limit its scope.

EXAMPLES

The tests below were carried out using an Austrian type B7 diesel fuel, meeting the specifications of the EN590 standard.

This virgin fuel is called G0.

A first fuel composition G1 was prepared by adding to fuel G0 a package of additives Al containing the following compounds:

- Procetane additive: ethyl-hexyl nitrate at a content of 300 ppm by mass in the fuel Gl,

Polyisobutylene succinimide deposit-reducing additive functionalized with a quaternary ammonium group at a content of 42 ppm by mass in the fuel Gl,

Polyisobutylene succinimide deposit-reducing additive functionalized with a triazole group at a content of 30 ppm by mass in the fuel Gl.

A second fuel composition G2 was prepared by adding to fuel composition G1 a mixture of compounds of the alkyl phenol type (consisting of 15% by mass of 2,6-di-t-butyl-4-methyl phenol, and 85% by mass of the condensation product of 2,4-dimethyl-6-t-butyl phenol and 2,5-dimethyl-4-t-butyl phenol) at a content of 350 ppm by mass in fuel G2.

Three identical tests were carried out in accordance with the WLTP standardized test protocol, using an Opel Crossland X vehicle equipped with a Diesel engine with a displacement of 1560 cm3, 88 kW. This vehicle complies with the Euro 6b standard. The driving cycle linked to the WLTP protocol consists of carrying out, on the vehicle installed on a chassis dynamometer, a route with a defined profile of 23 kilometers over a period of 1800 seconds (30 minutes) with an initial cold start. The rolling profile alternates variable rolling speeds during four major phases, separated by stops (zero speed).

The three tests differ only in the nature of the fuel supplying the engine (G0, G1 and G2 respectively).

For each test, five cycles were carried out (each fuel was thus evaluated 5 times, in order to ensure the robustness and statistical validity of the results).

The levels of polluting agents emitted during each test were measured, in accordance with the methods defined in European regulation ECE-R83.05. The results obtained (average over the five cycles) are shown in Table I below:

[Table I]

The above results demonstrate that the addition to virgin diesel GO of the Al additive package leads to a consequent increase in nitrogen oxide (NOx) and particulate emissions. The composition of diesel fuel G2, further comprising akyl-phenol additives in accordance with the invention, makes it possible to very significantly reduce NOx emissions, by 28% compared to comparative diesel fuel G1 and by 17% compared to virgin diesel fuel from GO reference. With regard to the particles, the G2 composition makes it possible to reduce emissions by 95% compared to the comparative diesel fuel G1 and by 88% compared to the virgin reference diesel fuel GO. Furthermore, the total level of gaseous emissions is greatly reduced with the G2 fuel, compared to the comparative fuels G1 and G0.

Claims

1. Use for reducing emissions of nitrogen oxides and of at least one type of polluting agent selected from carbon monoxide and unburnt hydrocarbons during the combustion of a liquid fuel in an internal combustion engine ignition by compression, of a composition of additives comprising:

(i) one or more additives chosen from compounds having in their structure at least one alkyl-phenol group; and

(ii) one or more cetane number-improving additives selected from alkyl nitrates, aryl peroxides and alkyl peroxides; wherein the mass ratio of the amount of additive(s) (i) to the amount of additive(s) (ii) is within the range from 1:3 to 3:1.

2. . Use according to the preceding claim, characterized in that the additive(s) (i) are chosen from the compounds (i)a) comprising one or two phenolic ring(s) substituted by one or more alkyl groups chosen from methyl and t-butyl groups, and preferably from methyl-t-butyl phenols, dimethyl-t-butyl phenols, ethyl-t-butyl phenols, t-butyl phenols, di-t-butyl phenols , tri-t-butyl phenols, di-t-butyl-di-methyl phenols, and mixtures thereof.

3. Use according to the preceding claim, characterized in that the compound(s) (i)a) are chosen from (di)tert-butyl phenols, methyl-tert-butylphenols and di-methyl-tert- butylphenols, their mixtures, and their two-by-two condensation products, such as in particular 2,6-di-t-butyl-4-methyl phenol (BHT), 2,4-dimethyl-6-t-butyl phenol, 2,5-dimethyl-4-t-butyl phenol, 2,6 and 2,4 di-t-butyl phenol, 2,4,6-tri-t-butyl phenol, mixtures thereof, and their condensation products two by two.

4. Use according to claim 1, characterized in that the additive or additives (i) are chosen from modified alkylphenol-aldehyde resins (i) b) obtainable by Mannich reaction of an alkylphenol-condensation resin aldehyde: with at least one aldehyde and/or one ketone having from 1 to 8 carbon atoms carbon, preferably 1 to 4 carbon atoms; and at least one hydrocarbon compound having at least one alkylpolyamine group, having between 1 and 30 carbon atoms, preferably between 4 and 30 carbon atoms, said alkylphenol-aldehyde condensation resin itself being capable of being obtained by condensation : at least one alkylphenol substituted by at least one alkyl group, linear or branched, having 1 to 30 carbon atoms, preferably a monoalkylphenol, with at least one aldehyde and/or one ketone having 1 to 8 atoms carbon, preferably 1 to 4 carbon atoms.

5. Use according to the preceding claim, characterized in that the modified alkylphenol-aldehyde resins can be obtained from p-nonylphenol, formaldehyde and at least one hydrocarbon compound comprising at least one alkylpolyamine group.

6. Use according to any one of claims 4 and 5, characterized in that the modified alkylphenol-aldehyde resins are capable of being obtained from at least one alkylpolyamine having at least two primary amine groups, and at least one fatty chain having 12 to 24 carbon atoms, preferably 12 to 22 carbon atoms.

7. Use according to any one of the preceding claims, characterized in that the composition of additives comprises one or more compounds (i) a) comprising one or two phenolic ring(s) substituted by one or several alkyl groups selected from methyl and t-butyl groups, and one or more modified alkylphenol-aldehyde resins (i)b).

8. Use according to any one of the preceding claims, characterized in that the additive or additives (ii) are chosen from alkyl nitrates of formula R-NO3 with R an alkyl radical comprising from 2 to 12 carbon atoms, plus preferentially from 4 to 8 carbon atoms, and better still the additive (ii) is ethyl-hexyl-nitrate.

9. Use according to any one of the preceding claims, characterized in that the mass ratio of the quantity of additive(s) (i) to the quantity of additive(s) (ii) is included in the range from 1:2.5 to 2.5:1, preferably 1:2 to 2:1 and more preferably 1:1 to 1.5:1.

10. Use according to any one of the preceding claims, characterized in that the additive composition further comprises one or more deposit-reducing additive(s) (iii), chosen from the group consisting of amines, succinimides, alkenylsuccinimides, polyalkylamines, polyalkylpolyamines, polyetheramines, quaternary ammonium salts, and triazole derivatives; more preferably from polyisobutylene succinimides functionalized with a quaternary ammonium group, fatty acid amides functionalized with a quaternary ammonium group and their dimers such as di-(alkylamido-propyl-quaternary ammonium) compounds, alkylamidoalkyl betaines with a fatty chain and triazole derivatives; and even more preferably from polyisobutylene succinimides functionalized with a quaternary ammonium group and polyisobutylene succinimides functionalized with a triazole group.

11 . Use according to the preceding claim, characterized in that the ratio between the total weight content of compounds (i) having in their structure at least one alkyl-phenol group on the one hand and the total weight content of reducing additive(s) ) of deposits (iii) on the other hand ranges from 1:60 to 1:2, preferably from 1:20 to 1:3.

12. Use according to any one of the preceding claims, characterized in that the fuel is chosen from gas oils, biodiesels, gas oils of type B _x containing x% (v/v) of vegetable or animal oil esters with x a number greater than zero and less than or equal to 100, hydrotreated vegetable oils (HVO), and mixtures thereof; and preferably from type B gas oils _x containing x% (v/v) of vegetable or animal oil esters with x a number greater than zero and less than or equal to 100, the esters of oils vegetable being preferably chosen from fatty acid methyl esters and fatty acid ethyl esters.

13. Use according to any one of the preceding claims, for simultaneously reducing the emissions of nitrogen oxides, carbon monoxide and unburnt hydrocarbons.

14. Use according to any one of the preceding claims, to further reduce emissions of solid particles.

15. Use according to any one of the preceding claims, characterized in that the compression ignition engine is a hybrid diesel engine or a direct injection diesel engine, preferably a direct injection diesel engine and more preferably a diesel engine with Common-Rail injection system.

16. Use according to any one of claims 1 to 14, characterized in that the compression ignition engine is a marine engine.

17. Method for reducing emissions of nitrogen oxides and of at least one type of polluting agent chosen from carbon monoxide and unburned hydrocarbons during the combustion of a liquid fuel in an internal combustion engine at compression ignition, comprising the addition to said fuel of an additive composition as defined in any one of claims 1 to 12.