EP2675775A1

EP2675775A1 - Method for producing a fuel for internal combustion engines

Info

Publication number: EP2675775A1
Application number: EP12703766.1A
Authority: EP
Inventors: Wolfgang Maus
Original assignee: Emitec Gesellschaft fuer Emissionstechnologie mbH
Current assignee: Wm Engineering & Consulting GmbH
Priority date: 2011-02-18
Filing date: 2012-02-03
Publication date: 2013-12-25
Also published as: WO2012110339A1; WO2012110339A9

Abstract

The method according to the invention for producing a fuel (14, 15, 16) for internal combustion engines comprises the following steps: a) providing carbon dioxide (C0₂) (6); b) providing hydrogen (H₂) (11) from water (H₂0) (9); and c) synthesizing methanol (CH₃OH) (12) from the provided carbon dioxide (6) and hydrogen (11). The method according to the invention is characterized in that the carbon dioxide (6) provided in step a) is provided from the flue gas (4) of the combustion of a fuel (2). A further method step d) of a process (13, 17) for converting the methanol (12) into a fuel (14, 15, 16, 18) is preferably carried out subsequent to step c); particularly preferably said process is a methanol-to-gasoline (MTG) process (13). The method according to the invention advantageously permits the reprocessing of carbon dioxide (6) from the flue gas (4) from power plants (1) and the use thereof for synthesizing fuels (14, 15, 16), in particular gasoline fuel (14), for operating internal combustion engines, such as Otto engines in automobiles. The method according to the invention can thus be particularly advantageously used for processing the flue gases (4) of power plants (1) from fossil fuels (2), which occur in great volumes. Alternatively, the methanol (12) can also be converted to dimethylether (18) as diesel fuel.

Description

Process for producing a fuel for

Internal combustion engines Subject matter of the present invention is a process for producing a fuel for internal combustion engines, in particular for gasoline engines. The present invention is concerned with the reprocessing of carbon dioxide which is produced in flue gases during the combustion of fuels in power plants.

Recently, there is increasing discussion worldwide as to whether carbon dioxide, as a greenhouse gas, has a share in the possible warming of the Earth's atmosphere. Since internal combustion engines generate a good portion of human carbon dioxide emissions, the traffic and personal mobility of individual people is often considered to be one of the causes of this potential global warming. Another major emitter of carbon dioxide is the burning of fossil fuels to produce electricity and, if necessary, heat. It is unclear at the moment how personal mobility will develop in the future. If personal mobility is to be maintained as individual mobility, for example, as today by automobiles and the like, alternative drive concepts and alternative fuels have to be considered. However, since today's internal combustion engines have a significantly higher efficiency compared to earlier models, it must also be checked whether it is possible to provide fuels for these engines by alternative means. In recent years there has been an intensive discussion about the production of fuel from biomass. In addition to the very positive approaches of providing, for example, gasoline fuel or diesel fuel from biomass due to, for example, the positive C02 balance, there are also negative aspects of this process. For example, growing areas that were previously used to produce food are used to produce biomass and to produce fuel. This has negative effects on the production of food and thus on the nutritional status of the population, especially in so-called emerging and third world countries.

On this basis, the object of the present invention is to at least partially overcome the disadvantages known from the prior art. In particular, a method is to be specified with which an alternative way of providing fuel for internal combustion engines is provided.

These tasks are solved with the features of the independent claim. The dependent claims are directed to advantageous developments. The features listed individually in the patent claims can be combined with one another in any technologically meaningful manner and can be supplemented by explanatory facts from the description, wherein further embodiments of the invention are shown.

The inventive method for producing a fuel for internal combustion engines, comprising the following steps:

a) providing carbon dioxide (CO2);

b) providing hydrogen (H2) from water (H2O);

c) synthesizing methanol (CH OH) from the carbon dioxide and hydrogen provided; wherein the carbon dioxide provided in step a) is provided from the flue gas of the combustion of a fuel.

Preference is given to the combustion of a fossil fuel such as coal, oil or natural gas in a power plant. The invention Therefore, proper method leads to a possibility for meaningful treatment of carbon dioxide from the flue gas of power plants, this is not released into the atmosphere and is not stored, for example, stored underground, but from this methanol is produced, which can be used as fuel and from the one Fuel can be produced, such as in particular gasoline fuel, also gasoline fuel, with which a gasoline engine can be operated, or diesel fuel with which a diesel engine can be operated, so that here the carbon dioxide in a meaningful way for gas personal mobility through internal combustion engines, for example, in automobiles, motorized two-wheelers, and the like.

Methanol itself can be used as fuel for internal combustion engines, which requires specially designed internal combustion engines. Methanol can be highly compressed and has already been used experimentally in appropriately designed engines.

According to a further advantageous embodiment of the method, the methanol is advantageously used for intermediate storage of energy. This can be done in times when the energy demand is low and / or the energy supply is high, in general, therefore more energy than energy demand is available. Preferably, it is also possible to provide the carbon dioxide in liquid form from fossil-fueled power plants. The concentration and liquefaction of carbon dioxide from the flue gas of fossil power plants is a sensible alternative to the storage of the corresponding carbon dioxide in underground caverns.

According to an advantageous embodiment of the method according to the invention, the following step follows at step c):

d) performing a process for converting the methanol into at least one fuel, Energetic considerations and calculations of the applicant have shown that in this case a positive energy yield can be obtained, which is bound as chemical energy in the generated fuel, despite the energy-intensive implementation of, for example, the methanol-to-gasoline process (MTG) in step d) and the energy required for steps b) and c).

According to a further advantageous embodiment of the method, the fuel produced in step d) is advantageously used for intermediate storage of energy. This can be done in times when the energy demand is low and / or the energy supply is high, in general, therefore more energy than energy demand is available. According to a further advantageous embodiment of the method according to the invention, step d) comprises one of the following processes:

i) a methanol-to-gasoline (MTG) process for converting the methanol (12) into a fuel; and

ii) a methanol-to-dimethyl ether (MTL) process to convert the methanol to dimethyl ether as a fuel.

In the methanol-to-dimethyl ether process, methanol is catalytically converted into dimethyl ether, in particular this process is carried out on a zeolite. Dimethyl ether can be burned in the diesel engine because of its cetane number, which is usually in the range of 55 to 60, and thus can be used as a diesel fuel, without any structural changes to the engine itself are necessary.

According to a further advantageous embodiment of the method according to the invention, the at least one fuel which is provided in step d) comprises at least one of the following substances:

A) LPG (Liquefied Petrol Gas, LPG) comprising at least propane and butane; B) Natural Gas Substitute (SNG) comprising at least methane;

C) gasoline fuel; and

D) diesel fuel.

Benzene fuel is understood to mean in particular an Otto fuel. In general, gasoline fuel in this context refers to a fuel with which an internal combustion engine can be operated, for example an Otto fuel with a corresponding knock resistance. LPG and petrol are already being sold practically everywhere in Germany as fuels for the operation of gasoline engines. Natural gas substitute can be used as fuel as a substitute for so-called CNG also compressed natural gas (compressed natural gas). Thus, by the treatment of carbon dioxide in particular from the flue gas of power plants fuels can be produced in an advantageous manner, which can be used for the operation of internal combustion engines, inter alia, in automobiles. Diesel fuel is understood as meaning a fuel with which a diesel engine can be operated; in particular, a diesel fuel comprises at least partially methyl ether.

According to an advantageous embodiment of the method according to the invention, the flue gas of a power plant is used in step a). In particular, the flue gas of a coal power plant, preferably a lignite and / or hard coal power plant, an oil power plant and / or a gas power plant can be used.

According to an advantageous embodiment, the flue gas is subjected before step c) a carbon dioxide scrubbing.

This is understood to mean a process in which carbon dioxide having an impurity content of less than 5% by volume, preferably less than 3 Volume%, particularly preferably less than 2% by volume is obtained.

In particular, this is understood to mean a MDEA process or absorption with a polyethylene glycol dimethyl ether, in particular with a product commercially available under the name Genosorb 1753.

The MDEA process is understood to mean a carbon dioxide scrubbing with methyldiethanolamine, which is preferably carried out in a temperature range from 75.degree. C. to 85.degree. The methyldiethanolamine solution shows even at low carbon dioxide partial pressures a high loading of carbon dioxide, which can be degassed by relaxing to atmospheric pressure, a large part of the carbon dioxide.

The so-called Genosorb process is understood to mean carbon dioxide scrubbing with a polyethyleneglycol dimethyl ether, in particular with a substance sold under the name Genosorb 1753. The good gas solubility of acid gases such as carbon dioxide and hydrogen sulfide is advantageous in the leaching of carbon dioxide from flue gases.

Preference is given to carrying out a single-stage carbon dioxide scrubbing with which 85% by volume to 90% by volume of the carbon dioxide can be washed out in the flue gas. By the carbon dioxide laundry, an impurity content of 2% by volume and less in carbon dioxide is achieved.

According to an advantageous embodiment of the method according to the invention hydrogen is provided in step b) from the electrolysis of water.

In the case of electrolysis, preference is given to using electrical energy which is obtained by at least one of the following processes:

A) nuclear fission; B) nuclear fusion;

C) conversion of mechanical energy into electrical energy, in particular driven by at least one of the following forces: 1) wind and 2) flowing water; and

D) conversion of solar energy into electrical energy.

In this case, electrical energy is preferably used in the electrolysis as electrical energy, which is obtained from a process in which substantially no carbon dioxide is produced. This further improves the overall CO2 balance of the process. This is how sustainable carbon dioxide can be converted into fuel. The selection of the various alternatives A) to D) can be carried out depending on the circumstances. In the conversion of solar energy into electrical energy according to alternative D) can be used in particular photovoltaic electricity generated. Alternatively, electric power can be used, which is generated by the sun-driven evaporation of water with subsequent operation of a steam turbine. In the alternative C), in particular electric current can be used, which was obtained by wind energy through wind turbines. In the conversion of mechanical energy into electrical energy based on flowing water according to C2) can be used in particular on hydroelectric power plants or tidal power plants.

This embodiment of the method according to the invention leads to a positive carbon dioxide balance. So effectively sustainable carbon dioxide can be converted into fuels. This can be used to operate internal combustion engines and in particular to secure individual personal mobility. Preferably, the method according to the invention for temporary storage of energy can thus be used in which methanol or a fuel obtained in step d) is used as the chemical storage of the energy. This is particularly advantageous if a variable available electricity supply, for example in tidal or wind power plants. Here, the fuel prepared by the process according to the invention and / or the methanol can be used as a chemical storage for an oversupply of, for example, wind or Ge time energy.

In principle, it is possible to use the resulting methanol or the resulting fuel, in particular gasoline or diesel fuel, to generate electricity when there is a supply of electricity. This can be done by a corresponding internal combustion engine, in particular with catalytic exhaust gas purification, which drives a corresponding generator. This allows the use of the method according to the invention for intermediate storage of energy, which will become increasingly important in the increased use of renewable energies. This represents a sensible way of storing carbon dioxide from the flue gas of fossil-fueled power plants.

In the following, the invention with reference to the single figure is explained in more detail by way of example, without being limited to the embodiment shown there. They show schematically:

1 shows a first embodiment of the method according to the invention in the flow diagram;

Fig. 2 shows a second embodiment of the method according to the invention in the flow chart and;

3 shows a third embodiment of the method according to the invention in the flow chart.

According to the variant of the method according to the invention according to FIG. 1, in a power plant 1 a fossil fuel 2, preferably coal, with an oxygen-containing gas 3, preferably air, is enriched with oxygen. burned in the air or pure oxygen. The resulting flue gas 4 is fed to a carbon dioxide scrubber 5. In the carbon dioxide scrubber 5, an amine or carbonate wash is preferably carried out. This results in a substantially pure carbon dioxide 6 and a corresponding scrubber exhaust gas 7. The carbon dioxide 6 is fed to a methanol synthesis 8.

In parallel, water 9 is supplied to an electrolysis 10. This is obtained with electrical energy from in particular so-called regenerative energy, such as solar, wind, and / or water energy operated. As product of the electrolysis 10, hydrogen 11 is obtained, which is likewise fed to the methanol synthesis 8.

Here, in the context of the methanol synthesis 8, preference is given to using a low-pressure methanol synthesis process which is carried out at a pressure of about 50 bar to about 100 bar at temperatures between about 200 and about 300 ° C. The methanol synthesis process 8 is assisted by a corresponding catalyst. For example. are used as catalysts copper-zinc oxide Alummina catalysts. Basically, carbon dioxide is converted with hydrogen to methanol and water. The resulting water can in this case be supplied to the electrolysis 10 as water 9 again.

Alternatively, a high-pressure methanol synthesis process can be used, which is carried out at pressures of about 250 to 350 bar and temperatures of 360 to 380 ° C. As a further alternative, a medium pressure method can be used, which operates at an operating pressure of about 100 to about 250 bar in a temperature range of about 220 to about 300 ° C.

The methanol 12 produced in the methanol synthesis 8 is then fed to a "methanol-to-gasoline" (MTG) process 13. Here, an aromatic-rich hydrocarbon mixture is formed on zeolites from methanol The MTG process 13 usually provides three products are gasoline fuel 14, LPG 15 and Erdgassubstitut 16. The relative proportions of the products 14, 15, 16 result from the process parameters under which the MTG process 13 is performed. For example, can be obtained from 100 tons of methanol 39 tons of gasoline fuel 14, 3 tons of LPG 15 and 2 tons Erdgassubstitut 16, which still generates 56 tons of water.

By gasoline fuel 14 is meant a mixture of hydrocarbons, which is usually sold as gasoline fuel with different anti-knock properties. Under Erdgassubstitut a kind of artificial natural gas is also known by the term Subsitute Natural Gas, SNG, comprising at least methane and hydrogen regularly understood. Autogas 15, also sold as LPG, liquefied petroleum gas, is understood to mean a readily liquefiable gas mixture which comprises at least propane and butane. All of these products are fuels that can be used for operating an internal combustion engine and in particular for operating an automobile.

2 schematically shows a second embodiment variant of the method according to the invention. Identical elements are here provided with the same reference numerals as in FIG. For the sake of clarity, only the differences from the embodiment variant in FIG. 1 will be explained; for the remainder, reference is made to the description of FIG. 1. The methanol 12 formed in the methanol synthesis 8 is fed in this embodiment to a "methanol-to-dimethyl ether" (MTL) process 17, in which the methanol 12 is catalytically converted to wholly methylene 18. The resulting methyl ether 18 can be used as Substitut be used for conventional diesel fuels.

Fig. 3 shows schematically a third embodiment of the method according to the invention. Identical elements are here provided with the same reference numerals as in FIG. It is for the sake of clarity only the differences from the embodiment in Fig. 1 will be explained, for the rest, reference is made to the description of FIG. 1.

In the third embodiment, the resulting in the methanol synthesis 8 methanol 12 is used directly as the final product. It can be used for example as carburetor fuel in corresponding internal combustion engines.

The inventive method advantageously allows the reprocessing of carbon dioxide 6 from the flue gas 4 of power plants 1 and their use for the synthesis of fuels 14, 15, 16, in particular gasoline fuel 14, for the operation of internal combustion engines such as gasoline engines in automobiles. The inventive method can thus be used in a particularly advantageous manner for the treatment of the resulting in large quantities of flue gases 4 of power plants 1 from fossil fuels 2. Alternatively, the methanol 12 can be reacted in Dirne methyl ether 18 as a diesel fuel.

LIST OF REFERENCE NUMBERS

1 power plant

2 fossil fuel

3 oxygen-containing gas

4 flue gas

5 carbon dioxide scrubbers

6 carbon dioxide

7 scrubber exhaust

8 methanol synthesis

9 water

10 electrolysis

11 hydrogen

12 methanol

13 MTG process

14 gasoline fuel

15 LPG

16 natural gas substitute

17 methanol-to-dimethyl ether process

18 dimethyl ether

Claims

claims

Method for producing a fuel (14, 15, 16) for internal combustion engines, comprising the following steps:

a) providing carbon dioxide (CO2) (6);

b) providing hydrogen (H2) (11) from water (H2O) (9); c) synthesizing methanol (CHOH) (12) from the carbon dioxide (6) and hydrogen (11) provided;

characterized in that

the carbon dioxide (6) provided in step a) from the flue gas (4) is provided for combustion of a fuel (2).

Method according to Claim 1, in which the following step follows at step c):

d) carrying out a process (13, 17) for converting the methanol (12) into at least one fuel (14, 15, 16),

The method of claim 2, wherein step d) comprises one of the following processes:

ii) a methanol-to-dimethyl ether process (17) to convert the methanol to methyl ether (18) as a fuel.

Method according to one of the preceding claims, in which the at least one fuel (14, 15, 16) comprises at least one of the following substances:

A) LPG (Liquefied Petrol Gas, LPG) (15), comprising propane and butane;

B) Natural Gas Substitute (SNG) (16) comprising methane; C) gasoline fuel (14);

D) diesel fuel.

5. The method according to any one of the preceding claims, wherein the flue gas (4) of a power plant (1) in step a) is used.

6. The method according to any one of the preceding claims, wherein the flue gas (4) before step c) is subjected to a carbon dioxide scrubbing.

7. The method according to any one of the preceding claims, wherein in step b) hydrogen (11) from the electrolysis (10) of water (9) is provided.

Method according to claim 7, wherein the electrolysis (10) uses electrical energy obtained by at least one of the following processes:

A) nuclear fission;

B) nuclear fusion;

D) conversion of solar energy into electrical energy.