Fuel or combustible composition comprising ammonia and at least one unsaturated alcohol

Abstract

The present invention relates to a fuel or combustible composition comprising ammonia and from 0.05% to 20% by mass, relative to the total mass of the composition, of one or more unsaturated alcohol(s) comprising from 3 to 12 carbon atoms. This composition is useful for powering any device used to produce energy by combustion. The invention also relates to a method for producing energy comprising powering a device for producing energy by combustion (such as in particular an internal combustion engine or an industrial boiler) using such a composition.

Description

Title of the invention: Fuel or combustible composition comprising ammonia and at least one unsaturated alcohol

[0001] The present invention relates to an ammonia (NH3)-based fuel or combustible composition comprising one or more unsaturated alcohol(s). The invention also relates to the use of such a composition as a fuel or combustible for powering a combustion energy production system such as a heat engine or a boiler. STATE OF THE PRIOR ART

[0002] In order to reduce greenhouse gas emissions generated by the combustion of hydrocarbon-based fuels, the international community is studying the use of alternative fuels with low carbon dioxide emissions. In this perspective, ammonia is considered an interesting solution, particularly for the transport sectors (especially maritime transport) and electricity production in gas turbines.

[0003] Ammonia has multiple advantages, including but not limited to: - It is a completely decarbonized fuel which can be produced via different technologies, including from hydrogen of renewable origin; - Its combustion does not generate emissions of carbon dioxide CO2, sulfur gases (SOx), unburned hydrocarbons, or particles; - It can be used in existing engines and heating devices, with minor adaptations.

[0004] However, a significant difficulty encountered so far lies in the poor combustion performance of ammonia when used in combustion systems. Indeed, tests carried out so far using mixtures of air and ammonia have shown low flame speeds and a high minimum ignition energy. This fuel is difficult to self-ignite, the ammonia flame is relatively slow and is easily extinguished near the walls of the combustion chambers.

[0005] These phenomena have a negative impact on combustion systems using ammonia as fuel. They limit the efficiency of combustion and reduce the operability ranges of the systems they supply (for example in the case of an engine: limitation of engine speed, limitation of the power developed). They cause an increase in the energy consumption necessary to initiate combustion, and generate undesirable emissions of ammonia and nitrogen oxide in the exhaust.

[0006] One solution proposed in the prior art consists of adding gaseous hydrogen to the ammonia, either by direct addition (as described for example in the publication by Frigo S et al entitled “Further Insight into the Possibility to Fuel a SI Engine with Ammonia plus Hydrogen”, SAE Technical Paper Series. SAE International 400 Commonwealth Drive, Warrendale, PA, United States, 2014 or the publication by Mprch CS et al entitled “Ammonia / hydrogen mixtures in an Sl-engine: Engine performance and analysis of a proposed fuel System”, Fuel 2011, 90(2):854-64), or by cracking a portion of the ammonia into hydrogen as described for example in patent application US2017 / 348659.

[0007] The disadvantage of this solution is that it requires either the use of a large reserve of hydrogen in or near the ammonia-fed system, or the costly installation of an in-line ammonia cracking system.

[0008] Other work has proposed the addition of methane or dimethyl ether (DME) to ammonia, or the addition of conventional fossil carbon fuel fractions such as diesel or gasoline. However, these additions generate CO2 emissions from the degradation of hydrocarbon fractions during combustion. In addition, it is desirable to be able to formulate fuel and combustible compositions free of fossil bases.

[0009] Application WO 2021 / 030876 describes a fuel composition comprising a mixture of ammonia and an aqueous solution of sugar (in particular fructose, glucose or sucrose), which has better combustion properties.

[0010] However, it is necessary to use sugars at high levels, greater than 10% of the fuel composition, to obtain satisfactory results. The use of such compositions therefore represents a relatively high cost and increases CO2 emissions resulting from the degradation of sugars during combustion.

[0011] The present invention aims to remedy the problems described above, and in particular the problem of poor combustion performance of ammonia-based fuels.

[0012] The Applicant has now discovered that the addition to ammonia of a particular additive consisting of one or more unsaturated alcohols makes it possible to achieve these objectives.

[0013] The present invention thus relates to a fuel or combustible composition comprising ammonia and from 0.05% to 20% by mass, relative to the total mass of the composition, of one or more unsaturated alcohol(s) comprising from 3 to 12 carbon atoms.

[0014] This composition exhibits improved combustion performance, compared to ammonia-based fuel or combustible compositions.

[0015] In particular, the presence of the unsaturated alcohol(s) in the composition makes it possible to significantly reduce the auto-ignition time, which is a good indicator of the chemical reactivity of the fuel / combustible and air mixture during the combustion process. The minimum ignition energy level is also reduced substantially. The flame speed is increased, which allows for good quality, controlled combustion without detonations. The combustion efficiency is also increased, which makes it possible to reduce the consumption of fuel or ammonia-based fuel, which leads to energy savings and a reduction in the environmental impact linked to the production and transport of the fuel / combustible.

[0016] The present invention does not require the use of significant quantities of unsaturated alcohol, contents of the order of one percent by mass being already very effective.

[0017] The present invention also relates to the use of such a composition as fuel or as combustible in a device for producing energy by combustion such as in particular an internal combustion engine or a boiler.

[0018] The present invention finally relates to a method for producing energy comprising supplying a device for producing energy by combustion (such as in particular an internal combustion engine or a boiler) by means of a composition according to the invention.

[0019] Other objects, characteristics, aspects and advantages of the invention will appear even more clearly on reading the description which follows.

[0020] In what follows, and unless otherwise indicated, the limits of a domain of values ​​are included in this domain, in particular in the expressions “between” and “ranging from ... to ...”. Furthermore, the expressions "at least one" and "at least" used in this 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 refers to a compound or group containing N carbon atoms in its chemical structure. DETAILED DESCRIPTION

[0021] The composition of fuel or combustible The composition according to the invention is based on ammonia, which is its main constituent.

[0022] Ammonia is used, in a manner known per se, to denote the compound with the chemical formula NH3. It is therefore anhydrous ammonia and not aqueous ammonia, which, in a manner also known per se, denotes an aqueous solution of ammonia whose formula is generally noted NH3.H2O, NH4OH, or aqueous NH3.

[0023] By "anhydrous ammonia" is meant that the ammonia does not comprise water in substantial content. However, the presence of water in low content (in particular less than or equal to 5% by mass) in the ammonia is not excluded from the scope of the invention. Water may for example be present in small quantity to reduce the risks of corrosion of the parts (in particular steel) in contact with the composition.

[0024] Preferably, the water content of the composition according to the invention is less than or equal to 5% by mass, more preferably less than or equal to 3% by mass, better still less than or equal to 2% by mass and even better still less than or equal to 1% by mass, or even less than or equal to 0.5% by mass relative to the total mass of the composition.

[0025] The composition according to the invention may comprise ammonia in the liquid state, in the gaseous state, or in both of these states (in particular in the form of a liquid and gas equilibrium), depending on the temperature and pressure conditions at which it is found. In particular, at a pressure greater than 10 bar at room temperature or at a temperature lower than -33°C at room pressure, the ammonia is in the liquid state. This form is preferred.

[0026] Preferably, the ammonia is at least partly in the liquid state, and preferably completely in the liquid state.

[0027] The ammonia content of the composition is advantageously greater than or equal to 60% by mass, preferably greater than or equal to 70% by mass, more preferably greater than or equal to 80% by mass, even more preferably greater than or equal to 90% by mass and better still greater than or equal to 95% by mass, relative to the total mass of the composition.

[0028] Unsaturated alcohols The composition comprises at least one C3 to C12 unsaturated alcohol.

[0029] In a manner known per se, an alcohol is an organic compound comprising at least one free hydroxyl function -OH. The alcohols used in the present invention are preferably mono-alcohols, i.e. compounds carrying a free hydroxyl function.

[0030] Said alcohols may be monounsaturated (i.e. they comprise a double bond in the hydrocarbon chain) or polyunsaturated (i.e. they comprise several double bonds and / or at least one triple bond in the hydrocarbon chain). Preferably, said alcohols are chosen from monounsaturated monoalcohols and polyunsaturated monoalcohols.

[0031] The unsaturated alcohols which can be used in the composition according to the invention are advantageously chosen from the compounds of the following formula (I): R2 (I) -------L...... QH R3 in which: - RI denotes a linear or branched hydrocarbon group containing from 2 to 11 carbon atoms and comprising one or two double bonds; - R2 denotes a hydrogen atom or a linear or branched alkyl group containing 1 to 8 carbon atoms; and - R3 denotes a hydrogen atom or a linear or branched alkyl group containing 1 to 8 carbon atoms.

[0032] Preferably, RI denotes a linear or branched hydrocarbon group containing from 2 to 9 carbon atoms, more preferably from 2 to 7 carbon atoms, and comprising one or two double bonds.

[0033] By hydrocarbon group is meant here a group formed solely of carbon and hydrogen atoms. In other words RI denotes a group of formula Cn H2n 4 or a group of formula CnH2n 3 with n an integer ranging from 2 to 11, preferably from 2 to 9 and more preferably from 2 to 7.

[0034] Preferably, R2 denotes a hydrogen atom or a linear or branched alkyl group containing 1 to 4 carbon atoms; preferably a hydrogen atom, a methyl group or an ethyl group; and more preferably a hydrogen atom or a methyl group.

[0035] Preferably, R3 denotes a hydrogen atom or a linear or branched alkyl group containing 1 to 4 carbon atoms; preferably a hydrogen atom, a methyl group or an ethyl group; and more preferably a hydrogen atom or a methyl group.

[0036] According to a preferred embodiment, the unsaturated alcohols are chosen from the compounds of formula (I) above, in which: - RI denotes a linear or branched hydrocarbon group containing from 2 to 7 carbon atoms and comprising a double bond; - R2 denotes a hydrogen atom or a methyl group; and - R3 denotes a hydrogen atom or a methyl group.

[0037] According to a preferred embodiment, the unsaturated alcohols are chosen from the following compounds: 3-methyl-2-buten-1-ol (or prenol), 3-methyl-3-buten-1-ol, 3-methyl-2-buten-1-ol, 2-methyl-3-buten-2-ol, 2-propen-1-ol, 3-buten-1-ol, 4-penten-1-ol, 3-buten-2-ol, 7-octen-1-ol, oct-1-en-3-ol (or octenol), and mixtures thereof.

[0038] 3-Methyl-2-buten-1-ol (or prenol) is particularly preferred.

[0039] The total content of the unsaturated alcohol(s) is in the range from 0.05% to 20% by mass, relative to the total mass of the composition. Preferably, this content is in the range from 0.1 to 10% by mass, more preferably from 0.2 to 6% by mass, and better still from 0.5 to 5% by mass, relative to the total mass of the composition.

[0040] According to one embodiment, the composition comprises one or more compounds of formula (I) as described above, including the preferred embodiments, in a total content in the range from 0.05% to 20% by mass, preferably from 0.1 to 10% by mass, more preferably from 0.2 to 6% by mass, better still from 0.5 to 5% by mass, and better still from 1 to 5% by mass, relative to the total mass of the composition.

[0041] According to a more preferred embodiment, the composition comprises one or more compounds chosen from 3-methyl-2-buten-1-ol (or prenol), 3-methyl-3-buten-1-ol, 3-methyl-2-buten-1-ol, 2-methyl-3-buten-2-ol, 2-propen-1-ol, 3-buten-1-ol, 4-penten-1-ol, 3-buten-2-ol, 7-octen-1-ol, oct-1-en-3-ol (or octenol), and mixtures thereof, in a total content in the range from 0.05% to 20% by mass, preferably from 0.1 to 10% by mass, more preferably from 0.2 to 6% by mass, better still from 0.5 to 5% by mass, and better still from 1 to 5% by mass, relative to the total mass of the composition.

[0042] According to an equally preferred embodiment, the composition comprises 3-methyl-2-buten-1-ol (prenol) in a content ranging from 0.05% to 20% by mass, preferably from 0.1 to 10% by mass, more preferably from 0.2 to 6% by mass, better still from 0.5 to 5% by mass, and better still from 1 to 5% by mass, relative to the total mass of the composition.

[0043] Other compounds The composition according to the invention may comprise one or more additional compounds, other than ammonia and the C3 to C12 unsaturated alcohols described above. It may thus comprise other bases, hydrocarbon or not, other than ammonia and unsaturated alcohols, as well as additives.

[0044] It may, for example, contain one or more additives consisting of organonitrate(s), and in particular one or more alkyl nitrates.

[0045] The alkyl nitrates which can be used in the composition according to the invention are advantageously chosen from the compounds of the following formula (I): Ri-NO3 (I) with Ri denoting an alkyl or cycloalkyl radical comprising from 1 to 12 carbon atoms.

[0046] Examples of alkyl nitrates that may be mentioned include methyl nitrate, ethyl nitrate, propyl nitrate, isopropyl nitrate, butyl nitrates (including n-butyl nitrate, 1-methylpropyl nitrate, 2-methylpropyl nitrate, tert-butyl nitrate, cyclobutyl nitrate), pentyl nitrates (e.g. amyl nitrate, isoamyl nitrate, 2-amyl nitrate, 3-amyl nitrate), hexyl nitrate, heptyl nitrate, 2-heptyl nitrate, octyl nitrate, isooctyl nitrate, 2-ethylhexyl nitrate, nonyl nitrate, decyl nitrate, undecyl nitrate, dodecyl nitrate, cyclopentyl nitrate, cyclohexyl, methyl cyclohexyl nitrate, and mixtures of these compounds.

[0047] Isopropyl nitrate and 2-ethylhexyl nitrate are preferred, and 2-ethylhexyl nitrate is particularly preferred.

[0048] The alkyl nitrate(s) may be present in the composition according to the invention in a total content advantageously within the range from 0.005% (50 ppm) to 5% by mass, preferably from 0.01% (100 ppm) to 2% by mass, more preferably from 0.02% (200 ppm) to 1% by mass, relative to the total mass of the composition.

[0049] The composition according to the invention can be prepared by simply mixing these ingredients. It is stable during storage.

[0050] It can be prepared and stored in a tank for later use, or prepared extemporaneously (i.e. immediately before use), by mixing the ammonia and the unsaturated alcohol(s) in the fuel or combustible intake circuit in the combustion chamber, for example by injecting the unsaturated alcohol(s) into the ammonia intake pipe in the combustion chamber.

[0051] The use The composition according to the invention is useful as a fuel or as a combustible for powering any device used to produce energy by combustion.

[0052] According to a first embodiment, the composition according to the invention is used as fuel to power an internal combustion engine.

[0053] In this embodiment, according to a first advantageous variant, the composition according to the invention is used as fuel to power a gas turbine.

[0054] In a manner known per se, a gas turbine, also called a combustion turbine, is a thermodynamic rotating machine from the family of internal combustion engines and which can be used for propulsion purposes, electricity production, or as a stationary engine (for example to drive pumps, compressors, etc.).

[0055] According to a second equally advantageous variant, the composition according to the invention is used as fuel to power a piston engine.

[0056] In this variant, the composition is useful for powering any known piston engine, including on-board engines and stationary engines. The invention applies in particular to marine engines, heavy goods vehicles, construction machinery or agricultural machinery such as, for example, tractors, public transport vehicles (buses, trains, etc.) as well as to engines of light vehicles such as cars, engines used in air or space propulsion (airplanes, rockets), as well as to engines used in stationary industrial applications.

[0057] The piston engine may in particular be chosen from compression ignition engines or diesel engines, spark ignition engines (including gasoline engines, CNG or natural gas engines for vehicles and hydrogen engines), mixed fuel engines (in English “dual fuel”).

[0058] Preferably, the composition according to the invention is used to power a compression ignition engine or diesel engine. Particularly preferably, the compression ignition engine is a marine engine (i.e. an engine used for the propulsion of a ship).

[0059] The composition according to the invention can be advantageously used to fuel a compression ignition engine with mixed carburetion (also commonly called a “dual fuel” engine). In this use, the fuel composition according to the invention fuels the engine in combination with another fuel different from the latter, such as for example hydrogen and / or a hydrocarbon fuel, preferably a hydrocarbon fuel. By “hydrocarbon fuel”, is meant in the present application a fuel comprising at least 50% by mass of hydrocarbons. The hydrocarbon fuel can be chosen from fuels of petroleum origin and in particular diesel and fuel oils of varying weight, renewable fuels (for example but not limited to those derived from biomass), and mixtures of these two types of fuels.According to a preferred embodiment, the hydrocarbon fuel is chosen from fuels based on diesel and / or heavy fuel oils of petroleum origin (such as marine fuels), bio-sourced fuels and their mixtures.

[0060] The two fuels are injected in different proportions depending on the power required from the engine. The hydrocarbon fuel is advantageously injected into the engine in small quantities, to initiate combustion by self-ignition in a mixture with air. This injection is called pilot injection. The fuel according to the invention is injected in a mixture with air to fuel the combustion.

[0061] Mixed fuel engines are typically powered in the prior art by combinations of fuels such as diesel / gasoline, diesel / LPG, diesel / CNG, or diesel / ethanol. In the case of a marine engine, the mixed fuel engine is powered in particular by means of combinations such as marine diesel or MGO (from the English "Marine GasOil") / natural gas, MGO / methanol, MGO / ammonia.

[0062] The use of a combination of hydrocarbon fuel and a fuel according to the invention having improved combustion performance makes it possible to significantly reduce the quantities of hydrocarbon fuel used for pilot injection, which makes it possible to reduce CO2 emissions, compared to the fuel combinations of the prior art.

[0063] In the case, for example, of a mixed-fuel marine engine fueled by an MGO / ammonia type combination, the improvement in the reactivity of the ammonia-based fuel makes it possible to reduce the quantity of pilot injection of MGO into the combustion chamber to initiate combustion and thus reduce the CO2 emissions linked to this pilot injection.

[0064] Preferably, the composition according to the invention is used to power a mixed-fuel compression-ignition engine fitted to a ship (i.e. a mixed-fuel marine diesel engine).

[0065] According to a second embodiment, the composition according to the invention is used as fuel to supply an industrial boiler, such as for example those used to generate electrical or thermal energy.

[0066] The first embodiment is preferred. In a particularly preferred manner, the composition according to the invention is used as fuel for powering a mixed-carburetion compression-ignition marine engine or a gas turbine (also called a combustion turbine).

[0067] The method The method of producing energy according to the present invention comprises supplying a combustion energy production device with a fuel or combustible composition as described above.

[0068] The energy production device can be chosen from any existing device, including, but not limited to, internal combustion engines and industrial boilers as described above.

[0069] Preferably, the energy production device is chosen from compression ignition engines and gas turbines (or combustion turbines).

[0070] According to a first variant, the method according to the invention comprises supplying said energy production device with the composition according to the invention from a reservoir containing it.

[0071] According to a second embodiment, the method according to the invention comprises: (1) a step of mixing ammonia and one or more unsaturated C3 to C12 alcohol(s) as described above in a content of 0.05% to 20% by mass relative to the total mass of the mixture; then (2) injecting the mixture from step (1) into the combustion chamber of said energy production device.

[0072] The mixing step (1) can be carried out for example in the fuel intake circuit towards the combustion chamber, for example by injecting the unsaturated alcohol(s) into the ammonia flow supplying the engine, upstream of the combustion chamber.

[0073] According to a preferred embodiment, the energy production device is a compression ignition engine with mixed carburetion (or “dual fuel” engine). In this embodiment, the method according to the invention comprises supplying the compression ignition engine with the fuel composition according to the invention and with another fuel different from the latter, preferably a hydrocarbon fuel as described above.

Claims

Claims

1. A fuel or combustible composition comprising ammonia and from 0.05% to 20% by mass, relative to the total mass of the composition, of one or more unsaturated alcohol(s) comprising from 3 to 12 carbon atoms.

2. Composition according to the preceding claim, characterized in that its ammonia content is greater than or equal to 60% by mass, preferably greater than or equal to 70% by mass, more preferably greater than or equal to 80% by mass, even more preferably greater than or equal to 90% by mass and better still greater than or equal to 95% by mass, relative to the total mass of the composition.

3. Composition according to any one of the preceding claims, characterized in that the unsaturated alcohol(s) are chosen from the compounds of the following formula (I): R2 (I) RI----1---OH R-3 in which: - RI denotes a linear or branched hydrocarbon group containing from 2 to 11 carbon atoms and comprising one or two double bonds; - R2 denotes a hydrogen atom or a linear or branched alkyl group containing 1 to 8 carbon atoms; and - R3 denotes a hydrogen atom or a linear or branched alkyl group containing 1 to 8 carbon atoms.

4. Composition according to the preceding claim, characterized in that the unsaturated alcohol(s) are chosen from the compounds of formula (I) in which: - RI denotes a linear or branched hydrocarbon group containing from 2 to 7 carbon atoms and comprising a double bond; - R2 denotes a hydrogen atom or a methyl group; and - R3 denotes a hydrogen atom or a methyl group.

5. Composition according to any one of the preceding claims, characterized in that the unsaturated alcohol(s) are chosen from the following compounds: 3-methyl-2-buten-l-ol (or prenol), 3-methyl-3-buten-l-ol, 3-methyl-2-buten-l-ol, 2-methyl-3-buten-2-ol, 2-propen-l-ol, 3-buten-l-ol, 4-penten-l-ol, 3-buten-2-ol, 7-octen-l-ol, oct-l-en-3-ol (or octenol), and mixtures thereof, and preferably the composition contains 3-methyl-2-buten-l-ol.

6. Composition according to any one of the preceding claims, characterized in that the total content of the unsaturated alcohol(s) is within the range from 0.1 to 10% by mass, preferably from 0.2 to 6% by mass, and more preferably from 0.5 to 5% by mass, relative to the total mass of the composition.

7. Use of a composition as defined in any one of the preceding claims as fuel or as combustible in a device for producing energy by combustion, preferably chosen from an internal combustion engine and a boiler such as an industrial boiler.

8. Use according to the preceding claim, as fuel for powering a gas turbine.

9. Use according to claim 7, as fuel for powering a piston engine, preferably chosen from compression ignition engines, spark ignition engines and mixed carburetion engines.

10. Use according to the preceding claim, characterized in that the piston engine is a compression ignition engine, preferably a mixed carburetion compression ignition engine and more preferably a marine engine.

11. Use according to one of claims 9 and 10, characterized in that said fuel composition supplies the engine in combination with a hydrocarbon fuel preferably chosen from fuels of petroleum origin, renewable fuels and mixtures of these two types of fuels; and more preferably chosen from fuels based on diesel of petroleum origin, biosourced fuels and their mixtures.

12. Use according to one of claims 7 to 11, characterized in that said fuel composition is prepared extemporaneously by mixing ammonia and the unsaturated alcohol(s) in the fuel or combustible intake circuit in the combustion chamber, for example by injecting the alcohol(s) unsaturated(s) in the ammonia inlet line into the combustion chamber.

13. A method of producing energy comprising powering a combustion energy producing device with a composition as defined in any one of claims 1 to 6.

14. Method according to the preceding claim, characterized in that the energy production device is chosen from compression ignition engines and gas turbines.

15. Method according to the preceding claim, characterized in that the energy production device is a compression ignition engine with mixed carburetion and in that it comprises supplying the engine with said fuel composition and with another fuel different from the latter, preferably a hydrocarbon fuel.