EP2310476A2

EP2310476A2 - Device and method for the electrothermal-chemical gasification of biomass

Info

Publication number: EP2310476A2
Application number: EP09741777A
Authority: EP
Inventors: Michael Prestel
Original assignee: AEN Autarke Energie GmbH
Current assignee: AEN Autarke Energie GmbH
Priority date: 2008-05-07
Filing date: 2009-03-11
Publication date: 2011-04-20
Also published as: WO2009135558A2; US20110203537A1; WO2009135559A2; EP2300567A2; WO2009135559A3; WO2009135558A3; US20110185634A1

Abstract

The invention relates to a device for extracting fuels from biomass while adding electrical energy, comprising the following components: a gasifier (33) for gasifying the biomass while adding electrical energy to a gas mixture, a reformer (35) for reforming the gas mixture obtained from the gasification, a gas scrubber (38) for scrubbing the reformed gas mixture, a catalyst (39) for carrying out a catalytic reaction for obtaining a reaction mixture from the scrubbed gas mixture, and a separator (40) for separating the fuel from the reaction mixture, the device further comprising devices for supplying hydrogen for hydrogenating the biomass or the gas mixture obtained from gasification and representing a closed system having a uniform internal pressure in an operating state.

Description

Apparatus and method for electro-thermo-chemical

Gasification of biomass

The description relates to a device and a method for the electro-thermo-chemical gasification of biomass, in particular for the electro-thermo-chemical gasification of biomass for the production of fuel from biomass with the supply of electrical energy.

In order to harness energy for humans, there are a variety of known energy conversion devices and facilities such as, for example, nuclear power plants, coal plants or solar systems and wind turbines. In particular, an energy conversion with the help of wind turbines, solar plants or plants for the production of energy from hydropower have the disadvantage that they can provide electrical energy only under certain external conditions. Thus, a sufficiently strong wind, sufficient solar radiation or a suitable amount of water must be available. Generation of electrical energy can therefore not be provided continuously or as required, but rather depends on external influences.

There is therefore a need in particular to be able to store electrical energy at the time of its formation, in order to make it available when needed. Various embodiments of energy storage are known from the prior art.

It has as its object to provide a device or a method for storing energy in order to retrieve it at a later time. Furthermore, the device and the method for storing the energy should have a high overall efficiency.

There is therefore provided an apparatus for recovering fuel from biomass by supplying electrical energy with the following components:

a gasifier for gasification of the biomass while supplying the electrical energy to a gas mixture, optionally a simultaneous hydrogenation of the heated biomass or the gas mixture obtained from the gasification can be carried out with hydrogen, a reformer for reforming the gas mixture obtained from the gasification, a gas scrubber for Washing the reformed gas mixture, a catalyst to carry out a catalytic reaction to recover a reaction mixture from the scrubbed gas mixture, and a separator to separate the fuel from the reaction mixture. In addition, the device comprises devices for supplying hydrogen for hydrogenating the biomass or the gas mixture obtained from the gasification and, in an operating state, represents a closed system with a uniform internal pressure.

The gas mixture obtained in the gasification is usually also referred to as so-called syngas. In the method proposed here, the internal pressure can be established independently by the gasification. As a uniform internal pressure in the sense of the present description, a system pressure of the described device is to be understood, which has a substantially equal pressure in the pressurized areas of the device. Pressure differences, which are inevitably necessary for moving the gas mixture, should therefore be low in relation to the prevailing system pressure, so that they are negligible in view of the system pressure. The same applies in particular to the area of the carburetor and of heat exchangers in which an increased pressure value due to the thermal expansion of the respective gas mixture is to be expected. Also in the area of inlets and outlets from the device, which will be explained in more detail later, there may be pressure drops or increases due to incoming and outgoing flow rates, but also have a negligible amount. For example, the system pressure in the device described can be in the order of 10 to 200 bar. In contrast, the pressure differences described are less than 0.1 bar and are therefore negligible, so that it can be spoken of a uniform internal pressure.

An apparatus for recovering fuel from a synthesis gas by means of a catalytic reaction in a catalyst and a separator in a separator is described, for example, in the German patent application entitled "Apparatus and process for fuel synthesis filed by the same applicant. It should be noted that the operation of the device described and the underlying method is explained below purely by way of example of alcohol, which is obtained as fuel from the biomass. Instead of the alcohol but other fuels such as diesel or gasoline can be produced. Possibly. In this case, the material of the catalyst used should be adjusted accordingly.

The optional simultaneous hydrogenation can, as described above, be carried out before the gasification of the biomass for the hydrogenation or H ₂ enrichment of the biomass or subsequently during the reforming. Both pure hydrogen and hydrogen-containing compounds can be used. For example, for the hydrogenation, methanol as the hydrogen-containing compound and water for steam reforming for the gasification of the biomass can be supplied. Accordingly, the device may comprise a device for supplying hydrogen-containing compounds to the biomass for their hydrogenation and / or also optionally a device for supplying water. A corresponding supply of hydrogen will be discussed in more detail below. The supply of water may in particular be provided if the biomass is too dry, so that it must be mixed with water.

For a better understanding of the processes occurring during the gasification, the reaction equations for a steam reforming of methane and water a taking place in this case will be described below by way of example. ) and synthesis gas production b.) by gasification of glucose (C ₆ Hi ₂ O ₆ ) from biomass and an overall reaction c.) of both reactions a.) and b.). This shows the synthesis gas production in b.) a hydrogen deficiency (b: 6 H ₂ ), which can be covered, for example, by the hydrogen produced in the steam reforming a.) of methane.

a.) 6 CH ₄ + 6 H ₂ O -> 6 CO + 18 H ₂ -> 6 CH ₃ OH + 6 H ₂ b.) C ₆ H ₁₂ O ₆ -> 6 CO + 6 H ₂ + (6 H ₂ H '

-> 6 CH ₃ OH C.) 6 CH ₄ + 6 H ₂ O + C ₆ H ₁₂ O ₆ - »12 CH ₃ OH

An alternative provision of hydrogen, for example by means of electrolysis, will be discussed in more detail below. Furthermore, it is also possible to provide a device for generating so-called solar hydrogen for generating and providing hydrogen.

According to one embodiment of the device, the device comprises means for hydrogen electrolysis to provide hydrogen for hydrogenation of the biomass or of the gas mixture obtained from the gasification. Thus, the apparatus may be configured to provide hydrogen for the hydrogenation described above. Of course, the hydrogen can alternatively be provided from other sources, such as the said device for generating solar hydrogen. If means are provided for hydrogen electrolysis, it is possible to obtain the electric current used for carrying out the electrolysis not only from conventional power sources but also from renewable energy conversion systems, such as wind turbines and photovoltaic systems.

Furthermore, the device can comprise at least one component from a group of components consisting of catalyst ren, filters, coolers, condensate separators, heat exchangers and molecular sieves.

Furthermore, the described device may comprise at least one tepid bath, which is provided for a gas purification, for example for the removal of halogen compounds. With the help of this Laugebads particular fluorine and chlorine (HCL and HF) can be withdrawn from a respective gas mixture. For example, caustic soda NaOH can be used as the caustic so that salt and water are formed in a reaction with HCl according to the following reaction equation:

NaOH + HCl - * NaCl + H ₂ O

Furthermore, a process for obtaining fuel, such as alcohol, from biomass by supplying electric energy is provided by the following steps:

Gasifying the biomass to a gas mixture in a gasifier,

Hydrogenating with hydrogen and reforming with water vapor of the gas mixture obtained from the gasification, washing the reformed gas mixture,

Recovering a reaction mixture from the scrubbed gas mixture by catalytic reaction in a catalyst and separating the fuel from the reaction mixture in a separator.

The method may further comprise a step of electrolysis of hydrogen for hydrogenation of biomass or the gas mixture recovered from the gasification. This hydrogen electrolysis can take place at the same system pressure or internal pressure of the system, otherwise it is a compression of the hydrogen produced possible or required. Moreover, it is possible that the method further comprises at least one step of a group of steps consisting of

a filtering step, a cooling step, a condensate separation step, and at least one pass through a heat exchanger.

In addition, the method may additionally comprise at least one of the following steps:

a) heating the gas mixture obtained from the gasification by means of electrical energy and / or by local oxygen combustion. For this purpose, for example, an electrically operated heating device can be provided, which additionally heats the gas mixture obtained by the gasification. Alternatively, the heater may also be gas operated to additionally heat the gas mixture, or to inject oxygen into the gas mixture and burn it locally. b) hydrogenating a gas mixture with hydrogen and then reforming the gas mixture with water vapor. With this step, any gas mixture can be added at any point of the device with hydrogen. This can be done, for example, in the gasifier by hydrogenating, for example, the gas mixture obtained by gasification and splitting up long-chain carbon monoxide. Hydrogen compounds (CH compounds, such as, for example, coke) effect. c) introducing the reformed gas mixture into a catalyst. For example, during and / or after the step of reforming, the gas mixture can be introduced into a catalyst to produce catalytic reactions. A catalyst may, for example, consist of suitable catalyst material, such as cobalt or platinum, which is arranged as a filling in a heat exchanger or subsequently to this. d) drying of the biomass prior to the gasification step using the gasification or reforming gas mixture by means of a countercurrent heat exchanger. Here, the biomass is dried before being fed into the gasifier or before the gasification by the high temperature of the gas mixture heated by the gasification or reforming. e) using water vapor recovered from the drying step for the step of reforming. With this step, water vapor produced in the above-described step of drying the biomass is utilized for reforming by a water gas reaction at higher temperatures. f) recycling at least a portion of the gaseous mixture remaining after the step of depositing into the gasifier. Hereby, the remaining gas mixture for renewed hydrogenation and reforming, for example, again supplied to the carburetor and thus undergo the described method or device again. g) separating components of the gas mixture remaining after the deposition step by suitable molecular sieves. By means of these molecular sieves, individual components of the remaining gas mixture, such as, for example, nitrogen, can be removed therefrom, before the remaining gas mixture, as shown, is supplied to the gasifier again. For this purpose, the molecular sieves in the device can be arranged in a main flow, so that the portion of the remaining gas mixture recycled in the direction of the carburetor is passed completely through the molecular sieves. Alternatively, the molecular sieves can be arranged in a side stream, so that only a partial separation takes place in the secondary stream and another part of the recycled gas mixture is passed via a main stream directly to the gasifier. Accordingly, the described device can provide recirculation devices so that a gas mixture from the separator can be returned to the gasifier or fed to the gasifier, the recirculation devices having main flow and / or bypass lines. h) burning off a portion of the gaseous mixture remaining after the step of depositing. Alternatively or in addition to the described separation, at least a portion of the remaining gas mixture can be burned off and removed in this way, and enrichment with inert gas components, such as, for example, N 2, can be prevented.

According to another embodiment, the method further comprises at least one of the steps a group of steps consisting of real gasification, gas vapor reforming, coke charring, coke hydrogenation, tar condensation, electrolysis and fuel synthesis, such as alcohol synthesis.

The device described above and the method described thus make it possible to produce fuel from biomass with the addition of electrical energy. In addition to the fuel, heat is released. As already explained at the outset, the following statements are merely illustrative of alcohol as a fuel. This makes it possible to convert electrical energy from electricity into chemical energy, which is stored in the form of the alcohol and is relatively easy to store. It can thus be stored in the form of alcohol electrical energy, which is obtained under favorable conditions, for example. Suitable wind conditions, with sufficient sunlight or other forms.

The biomass used here serves as a carbon supplier and can also be used to increase efficiency. The process described allows a conversion of the carbon (C) into an alcohol, for example methanol (CH ₃ OH), so that in this way a customary in previous methods conversion into CO ₂ can be prevented.

The conversion and storage of the electrical energy in the form of alcohol allows a simple and effective storage, since the alcohol can usually be obtained in a liquid state and can be stored in tanks. The energy stored in the alcohol can in different ways and Be used again or retrieved. For example. Alcohol is suitable for use as fuel or can be converted into heat or electricity.

In addition to simple storage, storage of the alcohol in tanks allows the alcohol to be supplied as needed, and thus the energy stored therein. The alcohol is available independently of external influences and can furthermore be transported in a simple manner.

Waste heat, which is produced in the described electro-thermo-chemical gasification of the biomass for storing energy in alcohol, can be made available, for example, for heating or hot water production. In this way, by means of the use of the waste heat or a so-called calorific value utilization, a comparatively high overall efficiency of the described method or device, for example of 90-100%, can be achieved.

The device described for carrying out the method described can be designed as a small decentralized device to be used, for example, in households or single-family homes. Basically, the device is arbitrarily scalable, so that even large devices or systems can be realized, which are centrally used.

The described method allows an addition of the energy amounts of electricity and biomass and allows by means of waste heat utilization a high overall efficiency.

The use of biomass allows a diverse biomass utilization and thus a large raw material base. In the The whole carbon of the biomass can be transformed considerably into alcohol. This results in essentially no carbon dioxide CO ₂ . Carbon dioxide CO ₂ is only released during a subsequent use of the alcohol, for example during the combustion of the alcohol. However, in this case only as much CO _{2 is} released as, for example, plants have taken up in the production of biomass. Only the use of biomass makes it possible to store the electrical energy of the stream in liquid form as alcohol. The power used for this purpose can be spatially separated from the alcohol production. For example. Wind turbines or solar plants can be set up in favorable locations, and the electricity produced can be directed to locations producing enough of the biomass to produce the alcohol. Of course, the devices for the production of alcohol can also be installed directly next to the power generating facilities such as. The wind turbines or solar panels.

With the help of the storage of energy, it is thus possible to provide a need-based provision of energy even in times of wind rains or at night. Basically, almost all of the carbon contained in the biomass can be converted to alcohol, leaving essentially no CO ₂ . The device uses electrical energy from electricity to generate or recover alcohol. This allows in particular a use of so-called excess electricity that occur in the described energy conversion or power generation plants usually in times of low utilization or low demand. As already described above, the device may comprise a gasifier for gasification of the biomass to a gas mixture or a synthesis gas. Furthermore, the apparatus may comprise a scrubber for scrubbing the gas mixture or for gas purification and / or an electrolysis device, it being possible to deposit inter alia carbon compounds from the gas mixture in the gas scrubber. The electrolyzer uses electricity to produce hydrogen by electrolysis. Furthermore, alcohol, for example methanol (CH ₃ OH), can be produced from the gas mixture or the synthesis gas and hydrogen (H ₂ ) in a separator of the device with the aid of an alcohol synthesis. The alcohol is discharged accordingly and can be stored in tanks. The waste heat of the device described can be used, for example, for heating or domestic water production or also as process heat in suitable media.

As noted above, the described apparatus for recovering the alcohol may utilize one or more (part) methods from a group of methods. This group includes ideal gasification, real gasification, gas-steam reforming, coke-making, coke-hydrogenation, tar-condensation, electrolysis and methanol synthesis.

The above-described process for obtaining the alcohol may further comprise the steps of: heating the biomass with power or gasifying the biomass into a gas mixture and cracking carbon-hydrogen compounds (CH compounds) contained in the gas mixture, with the help of the so-called steam reforming or the gas-steam reforming. The gassing and simultaneously heated gas mixture can be passed to a recovery of heat through countercurrent heat exchanger and are used in this way both for heating the gas mixture produced, as well as the biomass. In this way, only energy losses with electrical energy of the current used must be compensated, otherwise a power supply can be achieved by means of the recovery of heat.

Furthermore, it is possible to use a so-called intermittent procedure for burning off coke with oxygen O ₂ and water H ₂ O. The gas mixture or synthesis gas formed in the process described comprises carbon monoxide (CO), carbon dioxide (CO ₂ ) and hydrogen (H ₂ ). By means of a subsequent methanol synthesis, alcohol can be obtained from the gas mixture or synthesis gas.

Under the described gas mixture (unless specified) is the resulting gasification gasified gas mixture to understand its components or its composition may change by appropriate reactions in the individual steps or when using the individual (partial) method.

The described method may comprise a multi-stage gas processing, which consists of several steps. During the gasification of the biomass, heating takes place by means of the electrical energy of the stream and additional heating of the gas mixture by means of countercurrent heat exchangers. Furthermore, the gas treatment, as already mentioned, a gas-steam reforming, a coke-smoldering with oxygen (O ₂ ) and a tar Condensate-steam reforming include. A separation of possibly accumulating ash, which arises in particular during the gasification of the biomass, can be carried out by means of a preliminary separation in a ash box with rust. Furthermore, the device may comprise electrostatic filters, which are designed for the combustion of ash. It is also possible to use fabric fine filters. To prevent fouling or clogging of filters, so-called regeneration cycles can be provided in a controller of the device. In addition, a so-called purge cycle can be used for the alcohol synthesis, such as, for example, the methanol synthesis.

With the aid of the method described, a possible separation of long-chain carbon compounds, in particular hydrocarbon compounds from the biomass, such as, for example, tar deposits, can be avoided since this is present in gaseous form at high temperatures. Only on cooling do they condense and can lead to blockages. By means of suitable recirculation devices, however, the carbon compounds or tar-containing substances of the gas mixture can repeatedly pass through the device or parts of the device until the tar or residues of the tar have completely decomposed. This can be achieved by so-called cracking or splitting of the long-chain carbon compounds.

The regeneration cycle described above may include, for example, burning the device by briefly heating the entire system or the entire device or parts of the device. The described separation of the ash can be done, for example, by means of electrostatic filters, which are cleaned by means of regeneration can. Furthermore, it is possible to burn off filter surfaces of the filters in ash boxes. Electrostatic filters require in contrast to fine filters, such as. Fine tissue filters, apart from the emptying of the ash boxes no maintenance. Of course, a use of the fine filter or fine tissue filter is possible, which must be cleaned or replaced if necessary.

The catalyst used in the device allows a long service life when using low-sulfur biomass. However, if sulfur-containing biomass is used, a cyclic replacement of the catalyst may be necessary. In addition, a sulfur filter in the form of a desulfurization stage is also usable. This may be provided in the form of a zinc oxide layer (ZnO) on a suitable support. In this example, H ₂ S (hydrogen sulfide) with ZnO to ZnS (zinc sulfide) and H ₂ O (water) are converted, the reaction described, for example. In a temperature range between 200 and 400 ⁰ C can take place. A condensate removal, which may be necessary in the device, can take place, for example, by means of a separation with water and condensate.

In principle, all organic materials can be used as biomass. These include in particular wood, wood chips, pellets, as well as household waste, paper, cardboard, straw, grass and green waste. Algae, plankton and agricultural waste can also be used. PVC-free plastics or shredder waste can also be used as biomass. The biomass can be provided here in solid form or in liquid form. Liquid biomass is known, for example, under the name "Bio-Slurry" and offers the advantage of a significantly reduced volume. compared to biomass in solid form. However, the above list is purely exemplary and in no way exhaustive.

The efficiency of the method described or the device described depends greatly on the biomass used. For example. Therefore, in smaller and decentralized devices, higher quality biomass could be used to provide sufficient efficiency, whereas in large devices, almost any biomass, possibly with lower efficiency, could be used.

As already described above, it is possible to scale the device differently, so that different power levels can be achieved. The worse the direct conversion efficiency, the more economical small distributed systems with heat utilization are. The higher the efficiency, the more useful large devices.

It is at this point again explicitly referred to the introductory note, according to which the recovery of alcohol as a fuel is described purely by way of example and other fuels can be obtained instead of the alcohol with the described method and apparatus.

Further advantages and embodiment of the invention will become apparent from the description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained not only in the combination given, but also in others Combinations or alone, without departing from the scope of the present invention.

The invention is illustrated schematically by means of embodiments in the drawing and will be described in detail below with reference to the drawing.

Figure 1 shows a schematic representation of a system for the production of alcohol from electricity and biomass.

Figure 2 shows a schematic representation of an apparatus for obtaining alcohol from biomass while supplying electrical energy from electricity.

Figure 1 shows a schematic representation of a system for the production of fuel from electricity and biomass using the example of alcohol or methanol. Accordingly, the system comprises a device 300 for methanol production, is introduced into the biomass for the production of methanol and which is described in detail in the following Figure 2. Optionally, in addition to the biomass, methane and / or H ₂ can additionally be supplied for hydrogenating the biomass. The hydrogen H ₂ can in this case either by means of hydrogen electrolysis (if appropriate devices are provided for this purpose) produced or, for example. As solar hydrogen (solar H ₂ ) from a corresponding system (not shown) are supplied. In addition to the biomass, CO _{2 can also be introduced} instead of or in addition to the biomass for operating the device 300. Also optionally, water can be used for gasification of the biomass or for steam reforming of methane and water. Electric power used to operate device 300 may be from ordinary sources or from Generative sources, such as wind turbines 11 and / or photovoltaic systems 12 are obtained. As products, the device provides 300 inorganic constituents of the supplied materials in the form of ashes as well as in the running in the device chemical reactions occurring heat and the desired fuel in the form of methanol. If the device 300 provides devices for hydrogen electrolysis, oxygen can also be produced. The resulting methanol is passed from the device 300 into a reservoir 13 for storage, from which it can be retrieved for a variety of fuel uses. In addition to a purely exemplary use in appropriately adapted gasoline or diesel engines, use in corresponding fuel cells, such as, for example, direct methanol fuel cells (DMFC), as well as in a combined heat and power plant (CHP) 14 is also possible. There, when converted to electricity, heat and CO ₂ and possibly water are also produced.

FIG. 2 shows a device for obtaining alcohol from biomass while supplying electrical energy. For this purpose, the device 30 comprises a biomass container 31 for storing biomass. From the container 31, the biomass is conveyed via a feed 32 into a gasifier 33, where the biomass is gasified while supplying the electrical energy to a gas mixture. For this purpose, the carburetor is heated by means of electrical energy and the biomass is burned or gasified by pyrolysis. Any accumulating ash can be removed via suitable devices (not shown). The gasified gas mixture obtained in the gasification rises in a housing of the gasifier 33. At an upper end of the housing of the carburetor 33, a heater 34 is arranged, in which from the gasification obtained gas mixture electrically further heated and passed from the heater 34 in a heat exchanger 35. Alternatively, the heater 34 may include an after-heating with oxygen (not shown) so that oxygen is supplied and burned to generate heat. The heat exchanger 35 comprises a reformer for reforming the gaseous mixture obtained from the gasification, and supplies the reformed gas mixture within the casing of the gasifier 33 in the opposite direction to the gasified gas mixture ascending and discharges the reformed gas mixture from the casing of the gasifier 33. The heat exchanger 35 is designed such that it directs the reformed gas mixture in the opposite direction to the ascending gasified gas mixture and in this way heats the ascending gasified gas mixture by means of the further heated in the reforming reformed gas mixture.

Furthermore, a filling with catalytic function can be provided in the heat exchanger 35 or in associated lines of the heat exchanger 35, so that a catalyst can additionally be provided. This filling may comprise, for example, cobalt, platinum or other suitable catalytically active materials. After discharge of the reformed gas mixture this is passed from the heat exchanger 35 in a further, second heat exchanger 36, which is arranged along the feed 32 and provides for a heat exchange between the reformed gas mixture and conveyed in the feed biomass.

Subsequently, the reformed gas mixture is passed into a gas scrubber 37 to wash the reformed gas mixture. Here, the reformed gas mixture carbon-containing compounds, in particular hydrocarbons containing compounds (CH), such as tar, deprived. These withdrawn carbonaceous compounds can be fed back to the biomass by suitable means and in a new pass the gasifier 33, the heater 34 and the heat exchanger 35 with reformer pass and are removed in this way. Here, the usually long-chain carbon-containing compounds are split by the so-called cracking. However, the device for recycling carbonaceous compounds is not shown in FIG. The scrubbing gas mixture produced in the gas scrubber 37 can optionally be filtered, as shown, in a filter 38 which, for example, is designed as a fine-tissue filter or electrostatic filter. The resulting filtered or washed gas mixture is then passed through a catalytic reaction in a catalyst 39 for the production of alcohol from the washed or filtered gas mixture. Subsequently, a separation of the alcohol in a separator 40 and a discharge of the alcohol in a tank 41. Since only a part of the gas mixture reacts in a catalytic converter during the catalytic reaction, the device can be designed such that the gas mixture remaining after the separator 40 the catalyst 39 passes several times to bring remaining residues or components of the gas mixture also to the reaction. For this purpose, the remaining gas mixture is fed back to the catalyst 39 after passing through the separator 40. The remaining gas mixture is added to the filtered or scrubbed gas mixture fed from the scrubber 37 or the filter 38 and introduced together into the catalyst 39.

Furthermore, the device 30 has a device for hydrogen electrolysis 42 in order to prepare hydrogen. to deliver. The hydrogen is introduced, for example, into the feed 32 and / or the gasifier 33 and / or in the region of the separator 40. In addition, the device 30 is designed so that the entire device 30 is a closed system that can be acted upon with a uniform internal pressure. The internal pressure can be generated, for example, by the gasification of the biomass and thus provide the system pressure necessary in particular for the catalyst.

As a uniform internal pressure in the sense of the present description, a system pressure of the described device is to be understood, although the time is variable in the pressurized areas of the device, but at any time has a substantially equal pressure. Local pressure differences, which are inevitably necessary for the movement of the gas mixture, should therefore be small in relation to the prevailing system pressure, so that they are negligible in view of the system pressure. The same applies in particular to the area of the carburetor and of heat exchangers in which an increased pressure value due to the thermal expansion of the respective gas mixture is to be expected. Also in the area of inlets and outlets from the device, pressure drops or increases may occur due to incoming and outgoing volume flows, which, however, also have a negligible amount. For example, the system pressure in the device described can be in the order of 10 to 200 bar. In contrast, the pressure differences described are less than 0.1 bar and are therefore negligible. By contrast, the internal pressure can fluctuate over time within the limits described from 10 bar to 200 bar. Yet The same local internal pressure prevails at any time in the entire device, neglecting the described local pressure differences, so that it is possible to speak of a uniform internal pressure.

An embodiment of the entire device as a closed system with a uniform internal pressure allows in particular a direct supply of biomass from the biomass tank 31, since this is also integrated into the entire system and also is under the internal pressure. A connection of the biomass container 31 via a pressure lock is therefore not necessary.

The biomass container 31 can be designed so that it receives or stores a certain amount of biomass, for example, for several hours of operation of the plant or its daily requirement. Only when the container is empty, the internal pressure of the system is lowered to atmospheric pressure and the filling of the biomass container 31 can be done again. Subsequently, the gasification begins again, whereby the erfordereliche system pressure or internal pressure of the system is built independently.

With the aid of a so-called "purge gas" recirculation 43, after the illustrated alcohol separation in the separator 40, at least a portion of the remaining gas mixture can be recycled back into the gasifier 33 for gasification. In this way, gases or components of the remaining gas mixture such as methane can be converted again in the reformer to CO and H ₂ . An enrichment of nitrogen and other inert gases or gas components can be achieved by cyclical or continuous partial withdrawal from the recirculated remaining gas mixture (so-called or purge gas) can be prevented. From this so-called "purge gas" can either be separated by molecular sieves 44, the unwanted part or the corresponding molecules or it is burned directly. The resulting heat can be used for the method described or the device described.

Claims

claims

1. An apparatus for obtaining fuel from biomass while supplying electrical energy with the following components:

a gasifier (33) for gasifying the biomass while supplying the electric energy to a gas mixture, a reformer (35) for reforming the gas mixture obtained from the gasification, a scrubber (38) for washing the reformed gas mixture, a catalyst (39) for carrying out a catalytic reaction for obtaining a reaction mixture from the scrubbed gas mixture and a separator (40) for separating the fuel from the reaction mixture, said apparatus comprising means for supplying hydrogen for hydrogenating the biomass or the gas mixture obtained from the gasification and in an operating state represents a closed system with a uniform internal pressure.

2. Device according to claim 1, wherein the device comprises a device for supplying hydrogen-containing compounds to the biomass for their hydrogenation.

3. Device according to claim 1 or 2, wherein the device means for hydrogen electrolysis to provide of hydrogen for hydrogenation of the biomass or of the gas mixture obtained from the gasification.

4. Device according to one of claims 1 to 3, further comprising at least one component from a group of components consisting of catalysts (39), filters (38), coolers, condensate separators, heat exchangers and molecular sieves (44).

5. Device according to one of claims 1 to 4, further comprising recirculation devices (43), so that a gas mixture from the separator (40) in the carburetor (33) returned or the carburetor (33) can be supplied, wherein the Return devices (43) Hauptström- and / or secondary flow lines.

6. Device according to one of claims 1 to 5, wherein the device further comprises a device for supplying CO ₂ .

7. Device according to one of claims 1 to 6, wherein alcohol is obtained from the biomass as fuel.

8. A method of recovering fuel from biomass by supplying electrical energy, comprising the steps of:

Gasifying the biomass to a gas mixture in a gasifier,

Hydrogenating and reforming the gas mixture obtained from the gasification, washing the reformed gas mixture, recovering a reaction mixture from the washed gas mixture by catalytic reaction and

Separating the fuel from the reaction mixture in a separator.

9. The method of claim 8, further comprising a step of electrolysis of hydrogen for hydrogenation of biomass or the gas mixture obtained from the gasification.

10. The method of claim 8 or 9, wherein the method further comprises at least one step from the group of steps consisting of

a filtering step, a cooling step, a condensate separation step and at least one pass step through a heat exchanger.

11. The method of claim 10, wherein the group of steps further comprises at least one of the following steps:

Heating the gas mixture obtained from the gasification by means of electrical energy and / or by local oxygen combustion,

Hydrogenating a gas mixture with hydrogen and then reforming the gas mixture with water vapor,

Introducing the reformed gas mixture into a catalyst,

Drying the biomass prior to the gasification step by means of the gasification or reforming gas mixture by means of a countercurrent heat exchanger,

Using water vapor recovered from the step of drying for the step of reforming, Returning at least a portion of the gaseous mixture remaining after the separation step to the gasifier,

Separating components of the gas mixture remaining after the separation step by suitable molecular sieves,

Burning off at least a portion of the gaseous mixture remaining after the step of depositing.

12. The method according to any one of claims 8 to 11, wherein the method further comprises at least one of a group of steps consisting of a real gasification, a gas-steam reforming, a coke charring, a coke hydrogenation, a tar Condensation, electrolysis and fuel synthesis.

13. The method according to any one of claims 11 to 16, wherein alcohol is obtained from the biomass as fuel.