Fuel composition comprising ammonia and at least one organonitric compound

Abstract

The present invention relates to a fuel composition comprising at least 75% by mass of ammonia and from 0.05% to 20% by mass of one or more organonitrate compounds having from 1 to 12 carbon atoms, these contents being expressed by mass relative to the total mass of the composition. This composition is useful for powering any device used to produce energy by combustion. The invention also relates to a method of energy production comprising supplying a combustion energy production device (such as, in particular, an internal combustion engine or an industrial boiler) with such a composition.

Description

Title of the invention: Fuel composition comprising ammonia and at least one organonitrate compound

[0001] The present invention relates to an ammonia (NH3)-based fuel composition comprising one or more organonitrate compound(s). The invention also relates to the use of such a composition as a fuel to power a combustion-based energy production system such as a heat engine or boiler. PREVIOUS STATE OF THE 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 context, ammonia is considered a promising solution, particularly for the transport sector (especially maritime transport) and for electricity generation in gas turbines.

[0003] Ammonia has multiple advantages, including but not limited to: - It is a completely decarbonized fuel that can be produced via different technologies, including from renewable hydrogen; - 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 to date using air-ammonia mixtures have revealed low flame speeds and a high minimum ignition energy. This fuel is difficult to self-ignite; the ammonia flame is relatively slow and extinguishes easily near the walls of the combustion chambers.

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

[0006] One solution proposed in the prior art consists of adding gaseous hydrogen to 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 part 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 online ammonia cracking system.

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

[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 in significant proportions, exceeding 10% of the fuel composition, to obtain satisfactory results. The use of such compositions therefore represents a relatively high cost and increases CO2 emissions 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 adding to ammonia a particular additive consisting of one or more organonitrate compound(s) as defined below makes it possible to achieve these objectives.

[0013] The present invention thus relates to a fuel or combustible composition comprising at least 75% by mass of ammonia and from 0.05% to 20% by mass of one or more organonitrate compound(s) having from 1 to 12 carbon atoms, these contents being expressed by mass, relative to the total mass of the composition.

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

[0015] In particular, the presence of the organonitrate compound(s) in the composition makes it possible to increase the flame speed, which provides a better quality, better controlled combustion, without detonations.

[0016] Combustion efficiency is also increased, which reduces fuel or ammonia-based fuel consumption and results in energy savings as well as a reduction in the environmental impact related to the production and transport of fuel / combustible.

[0017] The presence of the organonitrate compound(s) also reduces the auto-ignition delay, which is a good indicator of the chemical reactivity of the fuel / combustible-air mixture during the combustion process. The minimum ignition energy level is also substantially reduced.

[0018] The present invention does not require the use of large quantities of the organonitrate compound(s), contents on the order of percent by mass being already very effective.

[0019] The present invention also relates to the use of such a composition as a fuel or combustible in a combustion energy production device such as, in particular, an internal combustion engine or a boiler.

[0020] The present invention finally relates to a method of energy production comprising supplying a combustion energy production device (such as, in particular, an internal combustion engine or a boiler) by means of a composition according to the invention.

[0021] Other objects, features, aspects and advantages of the invention will become even clearer upon reading the following description.

[0022] In what follows, and unless otherwise indicated, the bounds of a range of values ​​are included in that range, 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 to". Finally, in a manner known in itself, a compound or group in CN is designated as a compound or group containing in its chemical structure N carbon atoms. DETAILED DESCRIPTION

[0023] The composition of fuel or combustible The composition according to the invention is based on ammonia, which is its main constituent.

[0024] Ammonia is defined in a manner known per se as the compound with the chemical formula NH3. It is therefore anhydrous ammonia and not ammonia which is also known per se as an aqueous solution of ammonia whose formula is generally written NH3.H2O, NH4OH, or aqueous NH3.

[0025] By "anhydrous ammonia," it is understood that the ammonia does not contain water in substantial amounts. However, the presence of water in small amounts (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 quantities to reduce the risk of corrosion of parts (particularly steel parts) in contact with the composition.

[0026] 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 less than or equal to 2% by mass and 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.

[0027] The composition according to the invention may comprise ammonia in the liquid state, in the gaseous state, or in both states (in particular in the form of a liquid-gas equilibrium), depending on the temperature and pressure conditions. In particular, at a pressure above 10 bar at ambient temperature or at a temperature below -33°C at ambient pressure, the ammonia is in the liquid state. This form is preferred.

[0028] Preferably, the ammonia is at least partly in liquid form, and preferably totally in liquid form.

[0029] The ammonia content of the composition is greater than or equal to 75% by mass, preferably greater than or equal to 80% by mass, more preferably greater than or equal to 85% 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.

[0030] Organonitrate compounds The composition includes at least one organonitrate compound in Ci to Ci2.

[0031] In a manner known per se, an organonitrated compound is an organic compound comprising at least one nitro function, i.e., -NO2. The compounds used in the present invention are preferably mononitrated, i.e., they comprise a nitro function -NO2.

[0032] The organonitrate compounds usable in the composition according to the invention are advantageously chosen from compounds of formula (I): R-NO2 in which R denotes a linear or branched, saturated or unsaturated, cyclic or acyclic hydrocarbon group, containing from 1 to 12 carbon atoms and preferably from 1 to 8 carbon atoms.

[0033] By hydrocarbon group we mean in a way known per se a group formed solely of carbon and hydrogen atoms.

[0034] The R group can advantageously be chosen from among alkyl groups, alkenyl groups and aromatic groups.

[0035] By alkenyl group is designated in a manner known per se the groups comprising at least one double bond between two carbon atoms, and preferably one or two double bonds.

[0036] Aromatic group refers to groups comprising a benzene ring substituted or not substituted by one or more alkyl groups.

[0037] According to a preferred embodiment, R is chosen from among the alkyl groups and aromatic groups, and more preferably from among the alkyl groups.

[0038] Examples of organonitrate compounds of formula (I) in which R designates an aromatic group are nitrobenzene, methyl-nitrobenzene and ethyl-nitrobenzene.

[0039] Examples of organonitrate compounds of formula (I) in which R denotes an alkyl group are nitromethane, nitroethane, 1-nitropropane, 2-nitropropane, 1-nitrobutane, tert-nitrobutane, nitropentanes.

[0040] According to a preferred embodiment, the organonitrate compound(s) are chosen from compounds of formula (I) in which R designates a linear or branched alkyl group containing from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, more preferably from 1 to 6 carbon atoms, and even more preferably from 1 to 5 carbon atoms. These compounds are designated nitroalkanes in the range Ci to Ci2.

[0041] More preferably, the organonitrate compound(s) are chosen from nitromethane, nitroethane, 1-nitropropane, 2-nitropropane, 1-nitrobutane, tert-nitrobutane, nitropentanes and mixtures of these compounds, and even more preferably from nitromethane, nitroethane, 1-nitropropane and mixtures thereof.

[0042] The total content of the organonitrate compound(s) as described above is in the range of 0.05% to 20% by mass, relative to the total mass of the composition. Preferably, this content is in the range of 0.1% to 10% by mass, more preferably 0.2% to 8% by mass, better 0.4% to 5% by mass, and even better 0.5% to 3% by mass, relative to the total mass of the composition.

[0043] According to one embodiment, the composition comprises one or more compounds of formula (I) as described above, including preferred embodiments, in a total content within the range of 0.05% to 20% by mass, preferably 0.1 to 10% by mass, more preferably 0.2 to 8% by mass, better 0.4 to 5% by mass and better still 0.5 to 3% by mass, relative to the total mass of the composition.

[0044] According to a more preferred embodiment, the composition comprises one or more compounds selected from the nitro-alkanes in the range of Ci to Ci2 in a total content in the range of 0.05% to 20% by mass, preferably 0.1 to 10% by mass, more preferably 0.2 to 8% by mass, better 0.4 to 5% by mass and better still 0.5 to 3% by mass, relative to the total mass of the composition.

[0045] According to a further preferred embodiment, the composition comprises one or more compounds selected from nitromethane, nitroethane, 1-nitropropane, 2-nitropropane, 1-nitrobutane, tert-nitrobutane and nitropentanes and preferably from nitromethane, nitroethane and 1-nitropropane, in a total content in the range of 0.05% to 20% by mass, preferably from 0.1% to 10% by mass, more preferably from 0.2% to 8% by mass, better from 0.4% to 5% by mass and better still from 0.5% to 3% by mass, relative to the total mass of the composition.

[0046] Other compounds The composition according to the invention may comprise one or more additional compounds, other than ammonia and the organonitrate compounds in the C1 to C12 ranges described above. It may thus comprise other bases, hydrocarbon or otherwise, other than ammonia, as well as additives.

[0047] It may for example contain one or more additives consisting of organonitrate(s), and in particular one or more alkyl nitrates.

[0048] The alkyl nitrates usable in the composition according to the invention are advantageously chosen from the compounds of the following formula (II): RrNO3 (II) with Ri denoting an alkyl or cyclo-alkyl radical comprising 1 to 12 carbon atoms.

[0049] Examples of alkyl nitrates 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 (for example, amyl nitrate, isoamyl nitrate, 2-amyl nitrate, 3-amyl nitrate), hexyl nitrate, heptyl nitrate, 2-heptyl nitrate, octyl nitrate, iso-octyl nitrate, 2-ethylhexyl nitrate, nonyl nitrate, decyl nitrate, undecyl nitrate, dodecyl nitrate, cyclopentyl nitrate, cyclohexyl nitrate, methylcyclohexyl nitrate, and mixtures of these compounds.

[0050] Isopropyl nitrate and 2-ethylhexyl nitrate are preferred, and 2-ethylhexyl nitrate is particularly preferred.

[0051] The alkyl nitrate(s) may be present in the composition according to the invention in a total content advantageously within the range of 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.

[0052] According to one embodiment, the composition does not include any C4-C1 alcohol or if such a C4-C1 alcohol is present in the composition, its content is less than or equal to 10% by mass, preferably less than or equal to 5% by mass, and more preferably less than or equal to 1% by mass, relative to the total mass of the composition.

[0053] According to a more preferred embodiment, the composition does not include methanol or if methanol is present in the composition, its content is less than or equal to 10% by mass, preferably less than or equal to 5% by mass, and more preferably less than or equal to 1% by mass, relative to the total mass of the composition.

[0054] The composition according to the invention can be prepared by simply mixing its ingredients. It is stable during storage.

[0055] It can be prepared and stored in a tank for later use, or prepared extemporaneously (i.e. immediately before use), by mixing ammonia and the organonitrate compound(s) in the fuel or combustible intake circuit in the combustion chamber, for example by injecting the organonitrate compound(s) into the ammonia intake line in the combustion chamber.

[0056] The use The composition according to the invention is useful as a fuel or combustible to power any device used to produce energy by combustion.

[0057] According to a first embodiment, the composition according to the invention is used as fuel to power an internal combustion engine.

[0058] In this embodiment, according to a first advantageous variant, the composition according to the invention is used as fuel to power a gas turbine.

[0059] As is known per se, a gas turbine, also called a combustion turbine, is a rotating thermodynamic machine of the family of internal combustion engines and can be used for propulsion, production of electricity, or as a stationary motor (for example to drive pumps, compressors,...).

[0060] According to a second, equally advantageous variant, the composition according to the invention is used as fuel to power a piston engine.

[0061] In this embodiment, the composition is useful for powering any known piston engine, including onboard and stationary engines. The invention is particularly applicable to marine engines, heavy-duty engines, construction equipment engines, and agricultural engines such as tractors, public transport vehicles (buses, trains, etc.), as well as to engines for light vehicles such as cars, engines used in aeronautical or space propulsion (airplanes, rockets), and engines used in stationary industrial applications.

[0062] The piston engine can in particular be chosen from among compression-ignition engines or Diesel engines, spark-ignition engines (including petrol engines, CNG or natural gas engines for vehicles and hydrogen engines), dual-fuel engines.

[0063] Preferably, the composition according to the invention is used to power a compression-ignition engine or a diesel engine. Particularly preferred, the compression-ignition engine is a marine engine (i.e., an engine used for propelling a ship).

[0064] The composition according to the invention can advantageously be used to power a dual-fuel, compression-ignition engine (also commonly referred to as a "dual-fuel" engine). In this application, the fuel composition according to the invention powers the engine in combination with another fuel different from itself, such as, for example, hydrogen and / or a hydrocarbon fuel, preferably a hydrocarbon fuel. In this application, "hydrocarbon fuel" means a fuel comprising at least 50% hydrocarbons by mass. The hydrocarbon fuel can be selected from petroleum-based fuels, including diesel and fuel oils of varying weights, 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-based fuels and their mixtures.

[0065] 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 auto-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 combustion.

[0066] In the prior art, dual-fuel engines are typically fueled by combinations of fuels such as diesel / gasoline, diesel / LPG, diesel / CNG, or diesel / ethanol. In the case of a marine engine, the dual-fuel engine is notably fueled by combinations such as marine diesel or MGO (from the English "Marine GasOil") / natural gas, MGO / methanol, or MGO / ammonia.

[0067] 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 prior art fuel combinations.

[0068] In the case, for example, of a marine engine with mixed fuel supplied by an MGO / ammonia type combination, improving the reactivity of the ammonia-based fuel makes it possible to reduce the amount of pilot injection of MGO into the combustion chamber to initiate combustion and thus reduce the CO2 emissions related to this pilot injection.

[0069] 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).

[0070] According to a second embodiment, the composition according to the invention is used as fuel to power an industrial boiler, such as, for example, those used to generate electrical or thermal energy.

[0071] The first embodiment is preferred. In a particularly preferred manner, the composition according to the invention is used as fuel to power a mixed-carburetion compression-ignition marine engine or a gas turbine (also called a combustion turbine).

[0072] The method The energy production method according to the present invention comprises supplying a combustion energy production device with a fuel or combustible composition as described above.

[0073] 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.

[0074] Preferably, the power generation device is chosen from compression-ignition engines and gas turbines (or combustion turbines).

[0075] 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.

[0076] According to a second embodiment, the method according to the invention comprises: (1) a step of mixing ammonia and one or more organonitrated compound(s) in the C1 to C12 range as described above in a content of 0.05% to 20% by mass relative to the total mass of the mixture; then (2) the injection of the mixture from step (1) into the combustion chamber of said power-producing device.

[0077] The mixing step (1) can be carried out for example in the fuel intake circuit to the combustion chamber, for example by injecting the organo-nitrate compound(s) into the ammonia flow supplying the engine, upstream of the combustion chamber.

[0078] According to a preferred embodiment, the power generation device is a dual-fuel compression-ignition engine (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

Demands

1. Fuel or combustible composition comprising at least 75% by mass of ammonia and from 0.05% to 20% by mass of one or more organonitrate compound(s) having from 1 to 12 carbon atoms, these contents being expressed by mass, relative to the total mass of the composition.

2. Composition according to the preceding claim, characterized in that its ammonia content is greater than or equal to 75% by mass, preferably greater than or equal to 80% by mass, more preferably greater than or equal to 85% 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 organonitrate compound(s) are selected from compounds of formula (I): R-NO2 in which R designates a linear or branched, saturated or unsaturated, cyclic or acyclic hydrocarbon group, containing from 1 to 12 carbon atoms and preferably from 1 to 8 carbon atoms.

4. Composition according to the preceding claim, characterized in that in formula (I) R is selected from alkyl groups, alkenyl groups and aromatic groups, more preferably from alkyl groups and aromatic groups; and more preferably R designates an alkyl group, linear or branched, containing from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, more preferably from 1 to 6 carbon atoms and better still from 1 to 5 carbon atoms.

5. Composition according to any one of the preceding claims, characterized in that the organonitrate compound(s) are selected from nitromethane, nitroethane, 1-nitropropane, 2-nitropropane, 1-nitrobutane, tert-nitrobutane, nitropentanes and mixtures of these compounds, and preferably from nitromethane, nitroethane, 1-nitropropane and mixtures thereof.

6. Composition according to any one of the preceding claims, characterized in that the total content of the organonitrated compound(s) is in the range of 0.1 to 10% by mass, preferably from 0.2 to 8% by mass, more preferably from 0.4 to 5% by mass and better still from 0.5 to 3% by mass, relative to the total mass of the composition.

7. Use of a composition as defined in any of the preceding claims as fuel or combustible in a combustion power generation device, preferably selected from an internal combustion engine and a boiler such as an industrial boiler.

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

9. Use according to claim 7, as fuel to power a piston engine, preferably selected 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 any one of claims 9 and 10, characterized in that said fuel composition supplies the engine in combination with a hydrocarbon fuel preferably selected from petroleum-based fuels, renewable fuels and mixtures of these two types of fuels; and more preferably selected from fuels based on diesel and / or heavy fuel oils of petroleum origin, bio-based fuels and mixtures thereof.

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

13. Method of energy production comprising supplying a combustion energy production 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 power generation device is selected from compression-ignition engines and gas turbines.

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