DE102021129810A1 - Process and device for generating hydrogen - Google Patents

Abstract

Process for converting carbon-containing raw materials and in particular biomass into hydrogen, comprising the steps:gasification of the carbon-containing raw materials (2) in a gasifier (1), with heated steam being introduced into the gasifier (1) and used for gasification;purification of the hydrogen-containing synthesis gas produced during the gasification, with the gasification preferably being an allothermic gasification and the heated steam being preferably used both as a gasifying agent and as a heat transfer medium for the gasification, characterized in that at least two different measuring devices are used to measure a variable that is characteristic of the conversion process and the method is controlled by a control device taking this characteristic variable into account.

Description

The present invention relates to an apparatus and a method for producing hydrogen.

It has long been known that hydrogen is a very important future energy carrier that can and will make a decisive contribution to the energy transition. It is therefore very important that the hydrogen produced is CO ₂ -neutral, which is now referred to as "green" or "blue" or "turquoise". The largest part (well over 90%) of the hydrogen existing on the market is "grey", obtained from fossil primary energy carriers with accompanying CO ₂ emissions, and for this reason it cannot contribute to the energy transition. The use of biomass for the present invention is another step to change this current situation.

State of the art

The oldest generation of large-scale amounts of hydrogen is based on coal gasification with water vapor (water gas reaction), through the chemical reaction: C + _H2O → CO + _H2

Today, the main process for hydrogen production is steam reforming, where the methane from natural gas reacts with the steam: CH ₄ + H ₂ O → CO + 3H ₂

The yield of hydrogen can be further increased by the water gas shift reaction at lower temperatures: CO + _H2O → _CO2 + _H2

It is still possible to use petroleum to produce hydrogen in a similar process.

Hydrogen produced in this way is referred to as “grey” because it comes from fossil fuels. If the carbon dioxide (CO ₂ ) produced is subsequently separated from process exhaust gases and stored underground (CCS - carbon capture and storage), this is referred to as "blue" hydrogen. This was also obtained from fossil fuels, but CO ₂ emissions are prevented or at least drastically reduced. However, the CCS process is controversial worldwide and classified as high-risk.

With the pyrolysis of methane, a CO ₂ -neutral hydrogen can also be produced because the product is solid carbon: CH ₄ → C + 2H ₂

Hydrogen obtained in this way is referred to as "turquoise". The disadvantage is that the yield is significantly lower than with steam reforming, but a major advantage is that no gaseous CO ₂ is produced. Solid carbon is much easier to store or landfill, and there are opportunities for other material uses as well. This process is still not used on an industrial scale.

Another possibility is to use the methane from biogas plants. In this case, the hydrogen obtained is immediately "green", even without CO ₂ separation. Since corresponding biogas plants are relatively small, these processes are not very attractive from an economic point of view.

The electrolysis of water is another method to obtain hydrogen. Today about 4% of the hydrogen produced worldwide is produced by electrolysis. However, such hydrogen is only "green" if the electricity used for this purpose is also "green". Electrolysis is expected to be the main source of green hydrogen in the future. The problem is that the "green" electricity from solar and wind systems is not always available. For this reason, the utilization of electrolysers is not high enough to enable economical operation. It will again be necessary to produce in countries with significantly more hours of sunshine per year and to export to other countries accordingly. However, the transport of hydrogen is very expensive and has not yet been implemented technically on a larger scale.

The present invention is therefore based on the object of providing a method and a device which enable hydrogen to be generated efficiently. According to the invention, this is achieved by the subject matter of the independent patent claims. Advantageous embodiments and developments are the subject of the dependent claims.

Furthermore, the applicant has determined that the efficiency of such systems can be improved by appropriate control of the same. Furthermore, in the operation of systems known from the prior art, it was found that after a certain period of operation, their efficiency or output dropped. Therefore, the invention is also based on the object of efficiency of such systems to be kept constant over longer periods of time.

These objects are also achieved by the subject matter of the following claims. It is further pointed out that the objects of the embodiments described as being advantageous can be combined with one another in any desired manner.

In a method according to the invention for converting carbon-containing raw materials and in particular biomass into hydrogen, the carbon-containing raw material is first gasified in a gasifier or reactor, with heated steam being introduced into the gasifier or reactor and being used for gasification and/or steam reforming. Furthermore, the hydrogen-containing synthesis gas produced during the gasification is then cleaned, with the gasification being an allothermal gasification and the heated steam being used both as a gasification agent and as a heat transfer medium for the gasification.

According to the invention, energy not used for the hydrogen gasification is at least partly reused for the generation and/or superheating of steam. In addition or in addition, it is possible to use the synthesis gas at least partially for the generation and/or superheating of steam.

It is therefore proposed within the scope of the invention that energy, which is lost during production, is largely or at least partially used again for the production of steam. In this way, a particularly efficient generation of hydrogen is possible.

In a further method according to the invention for converting carbon-containing raw materials and in particular biomass into hydrogen, the carbon-containing raw materials are gasified in a gasifier, with heated steam being introduced into the gasifier and being used for gasification. In a further process step, the hydrogen-containing synthesis gas produced during the gasification is cleaned, the gasification preferably being an allothermic gasification and the heated steam being used both as a gasification medium and as a heat transfer medium for the gasification.

According to the invention, a variable that is characteristic of the conversion process is measured using two different measuring devices, and the method and/or the device carrying out the method is controlled by a control device, taking this characteristic variable into account.

It is therefore a - preferably continuous - proposed measurement of a specific characteristic variable and the control of the gasification process.

The present invention is also aimed at a method for operating a device for converting carbonaceous raw materials and in particular biomass into hydrogen, the following steps being carried out in a working operation of the device. In a first process step, the carbon-containing raw materials are gasified in a gasification device, with heated steam being introduced into the gasifier and used for gasification. Furthermore, the hydrogen-containing synthesis gas produced during the gasification is cleaned, the gasification preferably being an allothermal gasification and the heated steam being used both as a gasification medium and as a heat carrier for the gasification.

The chemical energy of the synthesis gas at the gasifier outlet is preferably higher than the chemical energy of the fuel at the inlet. This increase in energy can be up to 130% and more. This can be achieved because sensible heat from the water vapor is converted into chemical energy.

According to the invention, in a cleaning operation of the device, which differs in particular from the working operation, components of the device and in particular the carburetor device are cleaned, with these components being cleaned with a free-flowing cleaning medium and in particular with heated steam as part of this cleaning.

In a preferred method, this characteristic variable mentioned above (which is measured) is a temperature, for example a temperature of the synthesis gas or of the steam.

Additionally or alternatively, different measured values and/or process parameters are recorded with a large number of measuring devices and/or sensor devices. In an advantageous method, measurement values are preferably recorded and preferably also stored over a longer period of time. These measured values are particularly preferably stored with a time allocation. In this way, the measured values and/or process parameters are recorded over a period of time that is longer than 5 minutes, preferably longer than 30 minutes, preferably longer than one hour, preferably greater than 2 hours and particularly preferably greater than 5 hours.

The measured values and/or process parameters are preferably recorded continuously and/or clocked. In this way, a course of the measured values can also be determined.

For example, an n-tuple of measured values can be recorded at a specific point in time, such as two or more temperatures within the gasification device, a temperature of the synthesis gas. During the operation of the devices, such n-tuples of measured values can be repeatedly recorded and preferably also stored, particularly preferably with a chronological assignment. It is also possible for correspondingly recorded measured values to be transmitted to a higher-level storage device at regular intervals.

In this case, it is possible for the recorded data to be transmitted to a central storage device, which can thus preferably also store and/or log the recording of the measured values over longer periods of time.

In a further preferred method, an evaluation device and/or processor device derives information from the data which is characteristic of the operation of the device or the method. In a preferred method, artificial intelligence is used to evaluate this data, in particular in order to be able to make statements about future behavior during the method or about the behavior of the device.

In a further preferred method, the characteristic variable is selected from a group of variables which include a temperature of the water vapor occurring during gasification, a temperature of the synthesis gas, a pressure of the synthesis gas, a torque of a drive device which conveys the biomass to the gasifier, a Flow rate and the like contains.

In a preferred method, the carbon-containing raw materials are fed to the gasification process by means of a conveyor, and this conveyor is preferably controlled and in particular regulated on the basis of at least one characteristic variable.

It is conceivable and preferred that the characteristic variable is a drive torque of a drive device of the conveyor device. However, it would also be possible for control and/or regulation to take place on the basis of a temperature of the water vapor or of the synthesis gas.

In a further preferred method, at least one parameter that is characteristic of a conveyor device is measured. This can preferably be, for example, a rotational speed of a conveyor rake or a conveyor screw or a torque of a drive device of this conveyor device.

The conveying device preferably has an electrically operated drive device and in particular an electric motor.

In a further preferred embodiment, the device has a turbine and in particular a gas turbine. The device preferably has a generator. In this way, a self-sufficient operation of the system is possible.

In a further preferred method, a temperature that is characteristic of the gasification process is measured and, in particular, this temperature is measured at at least two different positions of a gasification device.

A conveyor device is particularly preferably controlled and/or regulated as a function of this temperature. In a further preferred embodiment, the temperature is measured at at least three, preferably at least four, preferably at least five different positions and/or points of the carburetor or the carburetor device. In a preferred embodiment, at least three, preferably at least four and preferably at least five temperature measuring devices are arranged on or in the gasification device, which determine a corresponding temperature in different altitude zones. These temperatures are also used to control and/or regulate the supply of the biomass or the material to be gasified.

Furthermore, a comparison device is preferably provided, which compares the measured actual values of the temperatures with setpoint values. The conveyor device is preferably controlled on the basis of this comparison. It is thus possible for the actual temperatures occurring at the different positions of the gasification device to be measured and compared with the target temperatures to be expected there. If a discrepancy between the actual values and the target values is found, which is outside a specified tolerance range, the conveyor device can be controlled accordingly.

In this case, a warning can also be issued to the user. Also in response to these values, the supply or the temperature of the water vapor into the gasifier can be changed.

In a further preferred method, a temperature and/or a pressure of the synthesis gas produced during gasification is measured. This pressure or the temperature can, for example, also be characteristic of the gasification process or also of downstream processes. This is explained in more detail below. In this case, this temperature is preferably measured directly at an exit point of the synthesis gas.

In a preferred method, the fuel is checked by means of at least one sensor device. It is possible to determine a temperature of the synthesis gas in order to be able to draw conclusions about the fuel used or the material used for gasification.

In addition, it is possible that an electrical or mechanical parameter of the above-mentioned conveying device for the material to be gasified is determined, such as an electric current or a torque of a rake that is used for conveying. In this way, conclusions can be drawn about the material to be gasified.

In addition, it is also possible to determine a pH value of the biomass or the synthesis gas. In this way, too, conclusions can be drawn about the biomass used for gasification.

In a further preferred method it would also be possible to monitor the conveying of the material to be gasified by means of an inspection device such as a video camera.

The cleaning of the device described above is preferably carried out with a heated, free-flowing cleaning medium. In a particularly preferred method, it is proposed that the same medium that is also used for gasification is also used for cleaning the device. In this way, the device can be freed from deposits in particular, but not exclusively from tars.

In a preferred method, data of the cleaning process are monitored, such as in particular but not exclusively a duration of the cleaning, a temperature of the cleaning media used, pressures, flow rates and possibly also pressure profiles. A cleaning operation and a working operation are particularly preferably different. Thus, it is preferably not possible to carry out a cleaning operation during the working operation and, conversely, the working operation can also preferably not take place during the cleaning operation.

In a preferred method, steam is heated to a predetermined temperature for the purpose of cleaning, and the gasifier and/or connecting lines which discharge the synthesis gas from the gasifiers are cleaned in this way. For cleaning purposes, the steam is particularly preferably heated to a higher temperature than in an operating state or during working operation. The temperature of the steam used for cleaning is preferably between 150°C and 800°C, preferably between 150°C and 600°C and particularly preferably between 200°C and 500°C.

In a further preferred embodiment, the lines for the synthesis gas and/or the lines for supplying the steam are made of stainless steel.

In a preferred method, a process variable that is characteristic of the work operation is measured at least at times and preferably during the work operation, and a cleaning operation is initiated on the basis of this process variable. This means that a specific process variable is measured and if this preferably exceeds or falls below a specific threshold value, cleaning of the gasification device is triggered.

The process variable is preferably a pressure and in particular a pressure of the synthesis gas. This pressure is preferably measured continuously and particularly preferably also measured over a longer period of time. In a preferred method, the pressure of the synthesis gas is measured at several positions in the device. In a further preferred method, the pressure of the synthesis gas is measured using redundant measuring devices.

In a further preferred method, further components of the device are cleaned, with these components preferably being selected from a group of components which includes valves, piping devices, heat exchangers, coolers, filter devices and the like.

In another preferred method, components of the device before or after removed from the device during the cleaning process.

In a further preferred method, the device is at least temporarily cleaned and/or rinsed with a further cleaning medium which differs from the above-mentioned first cleaning medium.

In a further preferred method, valves of the device are switched at least temporarily during the cleaning operation in order to carry out cleaning of different components of the device. It is thus possible, for example, for different heat exchangers or different cooling units to be cleaned by means of a corresponding circuit.

In a further preferred method, components of the device are cleaned manually. For example, it is possible for certain components of the device to be removed from the device and cleaned manually. It is also possible, for example, for covers to be removed and then, in particular, manual cleaning to be carried out. In addition, it would also be possible for these components to be cleaned using a second cleaning medium.

In another preferred method, components of the devices are bypassed or bypassed while the cleaning is performed. It is therefore possible that some units, for example the cooling units, are not cleaned using steam.

In a further preferred method, consumption of cleaning agents, for example consumption of steam, is determined. Such consumption is particularly preferably determined for each cleaning process. In this way, conclusions can be drawn about the efficiency of the cleaning process.

In a further preferred method, components of the devices, for example the gasifier, are inspected during or after a cleaning process. It is possible for the device to have an inspection device such as a camera, which carries out this inspection.

In a further preferred method, components of the device are freed from ice and/or defrosted. It is conceivable that a defrosting agent is applied to these components or that they are heated, for example electrically or in some other way. In addition, the removal of ice can also be done mechanically. In a further preferred embodiment, the device has electrically operated heating devices which are used in particular for de-icing (in particular during a cleaning process).

In a further preferred method, after a cleaning operation, a resuming operation is carried out in order to convert the device into working operation and, within the scope of this resuming operation, the device is preferably operated with different process parameters than during working operation.

It is thus possible that during this start-up operation, steam is first generated and fed to the gasification device and then the carbon-containing products are fed to the gasification device.

Before the plant is started up, the lines and components mentioned are preferably preheated to a temperature between 50.degree. C. and 80.degree. During start-up the synthesis gas temperature increases and therefore the heat tracing power must also increase so that the wall temperature always follows the synthesis gas temperature.

Preferably, the lower part of the reactor 1 is filled with lime, dolomite, old ash (if any) or similar material. In this case, the regenerators 20 and 21 supply only slightly superheated steam, approx. 200°C to 300°C, in order to preheat the empty (without biomass!) reactor 1, cyclone 2, particle filter 5 and cracker 6.

The supply of steam is then preferably stopped and the filling of the reactor 1 is started. When the reactor 1 is sufficiently filled with the fuel, the supply of steam is preferably started again, so that the first amounts of synthesis gas are produced.

In a preferred process, the steam used for gasification has a temperature above 1000° C. in order to achieve allothermal gasification or steam reforming. The temperature is preferably above 1200°C and particularly preferably above 1400°C. Allothermic gasification means in particular that the heat input comes from outside.

In this way it is possible that the chemical energy of the synthesis gas at the gasifier outlet is higher than the chemical energy of the fuel at the inlet. This increase in energy can be up to 130% and more.

The method described here is preferably divided into at least two process steps, with first an allothermic gasification of the raw material (such as biomass and, for example, wood or straw) with steam, which serves as a gasification agent and energy carrier, being carried out. In the subsequent cleaning process, the gas is cleaned, in particular to remove dust and tar, and preferably these substances are then returned to the gasification process.

By using the highly superheated steam as a gasification agent and energy carrier, a high excess of water vapor is achieved in the gasifier. This excess is preferably always more than two, particularly preferably more than three.

Excess water vapor can be defined as the amount of steam from biomass input. In this case, the water vapor excess is preferably >1, particularly preferably >2 (e.g. mass of water vapor divided by mass of biomass). This excess steam means that, on the one hand, the formation of tar is reduced and, on the other hand, the tars produced are significantly shorter-chained and therefore less viscous than in the case of gasification without excess steam. The chemical energy of the synthesis gas at the gasifier outlet is preferably higher than the chemical energy of the fuel at the inlet. This increase in energy can be up to 130% and more.

In a further preferred method, a further gaseous medium is fed to the gasifier together with the steam. This is preferably oxygen or air, which is heated together with the water vapor to the temperature of the water vapor and fed to the gasifier. In another preferred method, the highest temperature within the gasifier is always above the ash melting point. In this way it can be achieved that ash is discharged in the liquid state. However, ash is preferably discharged in solid form.

The gasifier is preferably a fixed-bed countercurrent gasifier. In principle, different types of gasifiers according to the state of the art can be used. However, the particular advantage of a countercurrent fixed-bed gasifier is that individual zones are formed within this reactor, in which different temperatures and thus different processes occur. The different temperatures are based on the fact that the respective processes are strongly endothermic and the heat only comes from below.

In this way, the very high steam temperatures are used in a particularly advantageous manner. Since the highest vapor temperatures prevail in the inlet zone of the gasification agent, it is always possible to create the conditions for a liquid ash discharge. This is particularly advantageous in the case of biomass gasification, because there the ash melting points vary greatly depending on the type of fuel and the soil properties.

The steam temperature is preferably checked. In this way, sintering of the ash can be prevented. In a preferred method, lime is added or admixed. This is particularly possible with other fuels.

In an advantageous method, tar is separated from the synthesis gas and preferably at least a portion of this tar is returned to the gasification process. The tar is particularly preferably injected into a high-temperature zone of a regenerator. This regenerator is preferably used to generate steam. The tar is therefore preferably fed to the steam generation process.

In a further advantageous method, the synthesis gas is cooled in a first cooling step, and thermal energy produced during this cooling is preferably used for overheating or for generating steam. This cooling preferably takes place by means of a heat exchanger and the correspondingly dissipated thermal energy is particularly preferably supplied to the evaporation process.

In a further preferred method, drying and/or separation of volatile hydrocarbons takes place. This can be carried out, for example, in connection with a cooling process.

In a further preferred process step, the synthesis gas is cooled in a further cooling step, in particular a cooling step following the first cooling step, with preference being given to using a cooling device for this further cooling step in which temperatures are below 50°, preferably below 40°, preferably below 30 ° and more preferably below 20 ° prevail.

A so-called cryocooler is particularly preferably used in the second cooling step. This preferably allows complete drying of the synthesis gas. The synthesis gas is particularly preferably cooled to a temperature below 50°, preferably below 40°, preferably below 30°, before preferably below 20°, preferably below 10° and preferably below 5° and particularly preferably below 0°.

For the cryo-cooler or cryo-cooler, it is advantageous to use the devices and methods that are partially in the DE 10 2014 112 401 A1 have been described. The revelation of the DE 10 2014 112 401 A1 is hereby fully incorporated by reference into the disclosure herein. The use of such devices and methods leads to a more efficient solution compared to the prior art.

In a particularly preferred embodiment, a cryocooler is used for cooling and this cryocooler particularly preferably has at least two interacting regeneration devices. These regeneration devices are particularly preferably designed in such a way that the synthesis gas runs through them one after the other.

Particularly preferably, a first regeneration device and then a second regeneration device (of the synthesis gas) are passed through at least temporarily, and first the second regeneration device and then the first regeneration device (of the synthesis gas) are passed through at least temporarily.

A refrigeration system is particularly preferably connected upstream of this second cooling device and/or the second cooling process. In this way, the low temperatures of the synthesis gas that are advantageous here can be achieved.

In a preferred method, the cooled synthesis gas is filtered, a filter device preferably being used for this purpose and in particular a carbon filter device and/or a zinc oxide filter device and/or a doped carbon filter. Several of these filter devices are preferably used. This filtering is particularly preferably carried out after the synthesis gas has been cooled and in particular after the two-stage cooling process described above.

In a further preferred method, the cleaned and cooled hydrogen is compressed and in particular compressed with a pressure of at least 100 bar, preferably at least 200 bar and preferably at least 300 bar and preferably at least 350 bar. The hydrogen is preferably removed in this compressed state. A compressor is particularly preferably used for this purpose. The hydrogen gas thus compressed can then be used.

In another preferred method, the synthesis gas is compressed before the PSA plant. In a further preferred method, the separated hydrogen is then further compressed.

In a further preferred method, hydrogen and other gases are separated off, in particular by means of a separating device, a PSA system preferably being used for this purpose.

A waste gas from the separation device is particularly preferably used in order to generate and/or heat steam. This gas used can in turn be hydrogen. However, the use of other gases, such as methane, would also be conceivable.

It is thus possible that the waste gas (tail gas or offgas) from the PSA plant is used, which contains gases such as CO, CO ₂ , CH ₄ and a small amount of unused hydrogen. These gases still have sufficient chemical content (or calorific value) or sufficient chemical energy content. This energy is preferably used to generate steam again.

In a preferred method, the carbonaceous feedstocks are dried prior to being gasified. A combustion gas, or the combustion gases from at least one regenerator, is preferably used for this drying. This combustion gas preferably has a temperature which is above the saturated steam temperature and is preferably between 20K and 50K above this saturated steam temperature. In a preferred method, this combustion gas has a temperature which is more than 120°C, preferably more than 150°C and particularly preferably more than 170°C. This combustion gas preferably has a temperature which is less than 400°C, preferably less than 350°C and preferably less than 300°C.

The raw materials are preferably conveyed to the gasifier by means of a conveying device. This conveying device is particularly preferably selected from a group of conveying devices which contains screw conveyors, vibrating channels, biomass locks and the like

In a further preferred method, the synthesis gas is cleaned by means of a thermal cracker. At least two interacting regeneration devices are preferably used for this purpose. Oxygen is particularly preferred in the cracker in this process supplied for additional combustion. In particular, hydrogen is oxidized here, but other components of the synthesis gas can also be oxidized, such as CH ₄ or CO, which also depends in particular on the temperature, the residence time and the chemical equilibrium.

A corresponding device for cracking gases preferably has a feed line for a carbon-containing gas, by means of which the gas can be fed to a first heat exchanger with a bed of a thermal storage mass.

The storage mass is preferably alumina or aluminum oxide (Al ₂ O ₃ ). Aluminum oxide balls are preferably used, which preferably have a diameter of between 2 mm and 20 mm.

In addition, fills made of natural materials such as lime, dolomite or olivine can also be used (particularly at lower temperatures).

A thermal cracker is particularly preferably used, which breaks up the residual tars into short-chain molecular structures by means of very high temperatures, particularly advantageously between 800° C. and 1400° C. and preferably also by supplying a small amount of oxygen or air. In this so-called thermal cracking, the synthesis gas is brought to a very high temperature, which breaks down the long-chain molecular structures. At the same time, this process removes the remaining amount of dust. (Additional energy is preferably provided to cover heat of reaction in the cracking process)

The synthesis gas is preferably first heated in the cracker and then cooled again. The temperature differences during the heating and during the subsequent cooling preferably deviate from one another by no more than 40°, preferably by no more than 30°, preferably by no more than 20° and particularly preferably by no more than 10°.

In another process, the synthesis gas is only freed from dust by means of a cyclone (centrifugal separator), so that the tars remain in the synthesis gas. (Dust and tars are preferably partially separated in the cyclone). This is preferably ensured by electrical trace heating, with which the pipelines and the cyclone are kept at temperatures above the condensation temperature of the tars. The remaining tars are removed from the syngas together with the water in a condenser. This "tar water" forms a pumpable suspension, which evaporates, overheats and is returned to the gasification process.

The processing of the synthesis gas is described in more detail below.

A first combustion chamber arranged downstream in the flow direction of the gas is preferably provided, which in particular has a controllable supply device for another, oxygen-containing gas, by means of which partial oxidation of the carbon-containing gas takes place (in particular through substoichiometric oxygen supply).

Furthermore, a reactor arranged downstream of the first combustion chamber in the direction of flow of the gas is preferably provided, which has a bed of a possibly catalytically active material for the catalytic cracking of impurities in the carbon-containing gas.

A second combustion chamber is particularly preferably provided downstream of this reactor in the direction of flow of the carbon-containing gas, with an in particular controllable supply device for an oxygen-containing gas, by means of which partial oxidation of the catalytically processed carbon-containing gas takes place through (in particular substoichiometric) oxygen supply, and this combustion chamber is preferably in the flow direction of the gas, a second heat exchanger with a bed of a thermal storage mass is subsequently arranged, with the flow direction of the carbon-containing gas being particularly preferably reversible at least in a region which includes the first and second heat exchanger, the first and second combustion chamber and the reactor.

For the thermal cracker, it is advantageous to use the devices and methods that are partially in the DE 10 2012 111 900 A1 , DE 10 2012 111 894 A1 , or the EP 2 928 991 A1 have been described. The disclosure content of the publications mentioned is hereby fully incorporated by reference into the present disclosure. The use of such devices and methods leads to a more efficient solution compared to the prior art.

The present invention is also directed to a device for the conversion or steam reforming of raw materials containing carbon and in particular of biomass into hydrogen. This has a gasification device for gasifying the carbonaceous products. In addition, the device has a feed device which introduces heated steam into the gasification device in order to use it for gasification. Furthermore, the device has a cleaning device for cleaning the hydrogen-containing synthesis gas produced during the gasification, the gasification being an allothermic gasification and the heated steam being used both as a gasifying agent and as a heat transfer medium for the gasification. According to the invention, the device has a recovery device in order to reuse energy that is no longer usable for the production of hydrogen for the production and overheating of steam. The chemical energy of the synthesis gas at the gasifier outlet is preferably higher than the chemical energy of the fuel at the inlet. This increase in energy can be up to 130% and more. This energy increase is preferably at least 10%, preferably at least 20% and preferably at least 40% and particularly preferably at least 50% and particularly preferably at least 60%.

The device particularly preferably has a heating device for heating steam. In particular, the device has at least two and particularly preferably at least three interacting regenerators.

The present invention is further directed to a device for converting carbonaceous raw materials and in particular biomass into hydrogen. This device has a gasification device for the gasification of the carbonaceous raw materials, as well as a feed device which introduces heated steam into the gasifier in order to use it for gasification. Furthermore, a cleaning device for cleaning the hydrogen-containing synthesis gas produced during the gasification is provided, the gasification preferably being an allothermal gasification and the heated steam preferably being used both as a gasification medium and as a heat transfer medium for the gasification.

According to the invention, the device has a control device for controlling the conversion process and the device also has at least one first sensor device for detecting a first measured value characteristic of the conversion process and at least one second sensor device for detecting a second measured value characteristic of the conversion process, and the control device controls the Conversion process based on both the first and the second measurement value.

The present invention is further directed to a device for converting carbonaceous raw materials and in particular biomass into hydrogen. This has a gasification device for gasifying the carbonaceous raw materials, as well as a feed device which introduces heated steam into the gasification device in order to use it for gasification. Furthermore, the device has a cleaning device for cleaning the hydrogen-containing synthesis gas produced during the gasification, the gasification preferably being an allothermal gasification and the heated steam preferably being used both as a gasification medium and as a heat transfer medium for the gasification.

According to the invention, the device has or enables a cleaning operation for cleaning components of the device and in particular the carburetor, wherein these components can be cleaned with a free-flowing cleaning medium and in particular with steam during this cleaning operation.

In a further (alternative or additional) embodiment according to the invention, the device has at least two different measuring devices, which measure a variable characteristic of the conversion process, and a control device is provided, which controls the device taking this characteristic variable into account.

It is therefore also proposed within the scope of the device according to the invention that at least two measuring devices record measured values that are characteristic of the conversion process and that the device is controlled taking these measured values into account. The measuring devices are preferably suitable and intended for recording the measured values continuously over a specific period of time.

The device preferably has at least four temperature measuring devices for determining temperatures of the gasification device and at least one temperature measuring device for determining a temperature of the synthesis gas.

In a further preferred embodiment, the device has an analysis device for analyzing the synthesis gas with regard to its components.

In a further preferred embodiment, the device has a detection device for detecting an oxygen content of the synthesis gas.

The device preferably has a conveying device for conveying the carbonaceous products, and the control device preferably controls this conveying device taking into account the measured values mentioned.

The device preferably has a heating device for superheating steam, and this heating device is preferably also controlled and regulated as a function of measured values

In a further advantageous embodiment, the device has at least one and preferably at least two cooling devices for cooling synthesis gases containing hydrogen. At least two cooling devices are particularly preferably provided for cooling the hydrogen-containing synthesis gas, which are preferably arranged one behind the other in the direction of flow of the synthesis gas. This can be a cryocooler, for example.

The device preferably has at least one generating device and preferably at least two generating devices for generating steam. The generating device for generating and in particular for superheating steam is preferably a recuperator and particularly preferably a bulk material regenerator.

This bulk material regenerator particularly preferably has a heat storage mass made of bulk material, which is arranged within a container and which is particularly preferably arranged within two cylindrical grates that are coaxial with one another.

The interior of these two grates preferably surrounds a hot collection space for the hot gases. A circumferential wall is preferably arranged around the outer cylindrical grate and a collecting space for cold gases is particularly preferably provided between the outer cylindrical grate and this wall.

An increase in the pressure loss during a heating phase of the bulk material regenerator is preferably at least times as large as the value from rho g H, where rho or delta rho: the gas density at a temperature of 20 ° C, g the acceleration due to gravity and H is the height of the regenerator, and the throughput capacity for the gas is preferably at least 300 Nm3/h - m2 of the area of the hot grate at normal pressure. 2

In a further preferred method, the grain size of the bulk material is less than 15 mm. The particle size of the bulk material is preferably greater than 2 mm.

The outer diameter of the ring-shaped heat storage mass is preferably at most twice the inner diameter. In a further preferred embodiment, the bulk material regenerator is heated with a premix burner.

A regenerator of the type described here is particularly suitable for the generation of hydrogen described here.

In a preferred embodiment, at least one bulk material regenerator has a circulating device and/or a circulating conveyor device for circulating and/or re-conveying bulk material. A circulation of the bulk material can be made possible, preferably also during operation. It would thus be possible for bulk material to be conveyed away from a first area of the bulk material regenerator and fed to another area of the bulk material regenerator.

Such a tumbling and/or re-conveying of the bulk material preferably takes place in predetermined periods of time, for example 1-2 times per day

The device preferably has a measuring device which is suitable and intended for determining a discharge quantity of bulk material from the bulk material regenerator. This can be a weight measuring device, for example. While the bulk material is being circulated and/or circulated, a predetermined proportion of the bulk material is preferably located outside an active zone, i.e. outside a zone in which the bulk material is used for heating. This proportion is preferably between 1% and 2% of the total amount of bulk material.

In a further preferred embodiment, the sensor device described above is selected from a group of sensor devices which includes temperature measuring devices, pressure measuring devices, humidity measuring devices, torque measuring devices, flow measuring devices and the like. The sensor device is preferably suitable and intended for detecting a temperature of the water vapor. The measuring devices are particularly preferably designed at least partially as measuring probes.

In a further preferred embodiment, the device has a sensor device which determines the components of the synthesis gas, in particular the proportions of different gases. In addition, a measuring device is preferably also provided, which determines an oxygen content of the synthesis gas.

In a preferred embodiment, measuring devices are arranged at least partially redundantly. Thus, a temperature measuring device for measuring a temperature of the water steam or a temperature of the synthesis gas can be arranged redundantly, so that operation can continue if a measuring device fails.

In a preferred embodiment, the device has a timer which is suitable and intended for controlling individual parts of the plant. In a further preferred embodiment, the device has a display device which displays measured values that are displayed. It is also possible for this display device to communicate wirelessly with the individual measuring devices.

In a preferred embodiment, the display device is suitable and intended for displaying values displayed by the measuring devices. In this case, a measured value is preferably also assigned to a specific measuring device. It is thus possible for the display device to show a representation of the complete display and in each case to show which measured values were recorded at which point. In a preferred embodiment, the display device is portable, such as in the form of a portable touch screen. In this way, the operator can monitor and/or control the device from different locations.

In a further preferred embodiment, at least one measuring device has a transmission device which is suitable and intended for wirelessly outputting a measured signal. This measuring device and/or the transmitting device is/are preferably suitable and intended to output an identification in addition to the measured value, which in particular uniquely identifies the measuring device.

At least one of these sensor devices is preferably exchangeable. In a further preferred embodiment, the device has an operating device, by means of which a user can control or regulate certain parts of the system or influence the control or regulation thereof. It is thus possible for a user to automatically adjust valves or regulate the supply of biomass to the evaporator device. In a further preferred embodiment, a sensor device is provided which measures the moisture content of the biomass to be supplied. In addition, sensor devices can also be provided which determine a temperature of the above-mentioned pebble heaters. In addition, a sensor device can also be provided which enables the temperature of the already cooled medium, for example the cooled hydrogen, to be measured.

In a further preferred embodiment, the device has at least one sensor device which determines at least one environmental parameter. For example, a temperature measuring device can be provided which measures an ambient temperature or a measuring device for determining air humidity or air pressure.

In a preferred embodiment, the device has a conveying device driven by a drive device, which conveys the carbonaceous products to the gasification device, and this conveying device and/or the drive device is preferably controlled as a function of at least one measured value.

In a preferred embodiment, the carburetor device has at least two, preferably at least three and preferably at least four temperature measuring devices, which measure temperatures in different areas and/or zones of the carburetor device. The device preferably has at least five, preferably at least six, such temperature measuring devices. The conveyor device and/or the conveyor drive is particularly preferably controlled taking these temperature values into account.

In a preferred embodiment, the device has at least one and preferably at least two pressure measuring devices, which are preferably arranged at different positions of the device. The pressure measuring device is particularly preferably suitable and intended for determining a pressure drop or a pressure difference. It is thus possible for one of the pressure measuring devices to be arranged downstream of the second pressure measuring device. In this way it can be determined, for example, whether a cleaning process should be carried out on the device.

At least one temperature measuring device and preferably at least two temperature measuring devices are also preferably assigned to the generation and/or overheating device for heating water vapor. These can be located, for example, on the input side and output side of the overheating device. The temperature values measured by this temperature measuring device can be used to control the device and in particular to control the superheating of the steam.

In a further advantageous embodiment, the device has a (in particular electronic) memory device for storing a large number of data from different measuring devices ments measured values. In this case, it is possible for the memory device to record such measured values over a longer period of time. The memory device is particularly preferably suitable and intended for recording and/or determining the measured values with a time assignment. These measured values are particularly preferably recorded with a time value that is characteristic of a point in time. In a particularly preferred embodiment, the device has a timer device.

In a preferred embodiment, the device has a warning device which indicates a cleaning process to be carried out and/or malfunctions during the working operation of the device. In addition, the device preferably has a memory device which records characteristic data of the cleaning.

This can be, for example, a consumption of a cleaning medium, a temperature at which the cleaning was carried out, a duration of the cleaning and the like. In a further preferred embodiment, the device has a processor device, and in particular a remotely arranged processor device, by means of which remote maintenance and/or remote cleaning is made possible.

In a further advantageous embodiment, the device has a supply device in order to supply a second cleaning agent, such as an additive, to the first cleaning agent, for example steam. In this way, in addition to the steam, cleaning agents can also be used, which, for example, improve the cleaning of tars.

In a further preferred embodiment, the device has at least one measuring device, which detects a parameter that is characteristic of the working operation of the device. As mentioned above, this can be, for example, a temperature measuring device, a pressure measuring device and the like.

In a further advantageous embodiment, the device has a further combustion chamber, which is used in particular to carry out the cleaning process. This is preferably an afterburning chamber, which is used in particular to superheat water vapor even further.

In a further preferred embodiment, the device has a supply device for supplying (additional) oxygen. In this case, in particular for cleaning purposes and/or for carrying out the cleaning process, an additional quantity of oxygen can be supplied in order to further superheat the steam for cleaning purposes.

In a preferred embodiment, (additional) oxygen is supplied in response to and/or taking into account at least one measured value, for example in response to and/or taking into account a measured temperature, for example a measured temperature of the water vapor.

For further details regarding the bulk material regenerators, refer to the EP 0 620 909 B1 or the DE 42 36 619 C2 pointed out. The revelation of the EP 0 620 909 B1 as well as the DE 42 36 619 C2 is hereby fully incorporated by reference into the disclosure herein. The use of bulk material regenerators of this type results in a device that is more efficient than in the prior art. With regard to the DE 42 36 619 C2 reference is made in particular to column 2, line 55 to column 4, line 37.

The invention proposed here relates to a method and device for converting chemical energy from carbonaceous raw materials that are CO ₂ neutral into hydrogen. Raw materials can be various biomass (e.g. wood, wood residues, waste wood, agricultural waste, straw, fast-growing plants, waste from the food industry, fermentation residues, brewer's grains), organic waste (e.g. household waste, household waste, RDF - "refuse derived fuel", industrial waste) and the like.

With the method according to the invention of allothermic steam reforming of raw materials containing carbon, the chemical energy of the raw material is used in order to use the carbon content as much as possible for the production of hydrogen. The process achieves an extremely high yield of hydrogen by using superheated steam, which acts both as an energy source and as a reactant. The energy that can no longer be used for H ₂ production is reused for the production and overheating of steam, which leads to a very effective allothermic reaction. All of this results in a very economical process for CO ₂ -neutral hydrogen production. The chemical energy of the synthesis gas at the gasifier outlet is preferably higher than the chemical energy of the fuel at the inlet. This energy increase can be up to 130% or more. This energy increase is preferably at least 10%, preferably at least 20% and preferably at least 40% and particularly preferably at least 50% and particularly preferably at least 60%.

• Darin zeigen:
  • 1 eine schematische Darstellung einer erfindungsgemäßen Vorrichtung;
  • 2 eine Darstellung eines vorteilhaften thermischen Crackers;
  • 3 eine Darstellung einer Kühleinrichtung zum Kühlen des Synthesegases;
  • 4 eine Darstellung zur Verwendung von Teeren;
  • 5 eine weitere vorteilhafte Ausgestaltung der vorliegenden Erfindung;
  • 6 eine Darstellung zur Veranschaulichung der Steuerung der Vergasereinrichtung; und
  • 7 eine Darstellung zur Veranschaulichung des Prozessablaufs.

Further advantages and embodiments result from the attached drawings:

• Show in it:
  • 1 a schematic representation of a device according to the invention;
  • 2 an illustration of an advantageous thermal cracker;
  • 3 a representation of a cooling device for cooling the synthesis gas;
  • 4 an illustration of the use of tars;
  • 5 another advantageous embodiment of the present invention;
  • 6 a representation to illustrate the control of the carburetor device; and
  • 7 a representation to illustrate the process flow.

1 shows a schematic representation of a device 200 according to the invention for generating hydrogen from carbonaceous raw materials. The reference number 1 refers to a high-temperature reactor or gasifier, in which the raw material enters along the arrow P2. Reference number 31 designates an optional drying device for drying the raw material. From the line 19 comes a gas, or a gas mixture, which serves as an energy source for the reaction and as a reactant.

Furthermore, the device preferably has a transport device which conveys the raw material from the drying device to the high-temperature reactor. This transport device preferably has at least one and preferably several conveyor belts, at least one transport screw and/or at least one or more scraper chain conveyors. The raw material can be conveyed continuously or in cycles.

This gas coming from line 19 preferably consists of very highly superheated steam or has such. Allothermic generation of synthesis gas is thus preferably possible. If the raw material used contains mineral components, these leave the reactor as ash along the arrow P3. Depending on the prevailing temperature in this area of the reactor and the composition of the ash, the ash can be removed in a solid or liquid state.

Starting from the reactor 1, the synthesis gas produced, which contains a great deal of hydrogen, passes through a line 100 into a cyclone, or preferably into a multi-cyclone. In this cyclone 2, a large part of the tar and the dust that occurs is separated and temporarily stored in a reservoir 3. This cyclone thus represents a cleaning device for cleaning the synthesis gas

The tar is preferably transported through a line 109 by means of a pump 4, injected into the line 19 and thus fed back into the process. The injection point can be just before reactor 1, or already inside the reactor.

The thus pre-cleaned synthesis gas, in which residual tar is present together with remaining amounts of dust, passes through a further line 101 into a particle filter 5. There, the amount of dust is almost completely removed, so that only gaseous, volatile tars are still present in the synthesis gas. These are preferably destroyed in a thermal cracker 6, where the gases reach via line 102.

The device therefore preferably has two successive cleaning devices for cleaning the synthesis gas. The synthesis gas is preferably conveyed through the plant by the pressure originating from the steam.

Temperatures well above 800° C. prevail in the cracker, so that not only the tars but also the methane contained in the synthesis gas is cracked or pyrolysed. In this way, the H ₂ content in the synthesis gas increases further. In order to maintain the high temperature or to reach the reaction energy, a predetermined amount of oxygen or air is preferably supplied to the cracker along the arrow P4. As a result, part of the synthesis gas (H ₂ , CO, or CH ₄ ) oxidizes and the necessary energy is released.

After the thermal cracker, the synthesis gas reaches a gas cooler 7 via a line 103. In this gas cooler, the synthesis gas is cooled to such an extent that excess water vapor is condensed out in the condenser 8 connected downstream through a line 104. The waste heat (P7) can preferably be used to dry the biomass. Alternatively, the waste heat can also be fed into a local heating network.

Depending on the capacity of the plant, the diameter of this pipe ranges from a minimum of 100 mm and usually 800 mm. In extremely large systems, the pipes can also have a diameter of more than 1,000 mm. The pipelines are particularly preferably made of stainless steel in order to withstand the high temperatures on the one hand and the aggressive components of the synthe on the other to be able to withstand segases (such as formic acid or sulfuric acid).

The exiting synthesis gas still contains a lot of residual moisture, depending on the prevailing pressure and temperature. For this reason, the gas mixture is preferably passed through a line 105 into a cooling device, preferably a cryo-cooler 9, in which temperatures are preferably below 20°, preferably below 10° and particularly preferably 0° C. and particularly preferably below -5° C prevail below -10°C. This completely dries the synthesis gas and frees it from highly volatile gaseous hydrocarbons such as benzene, toluene, naphthalene, etc., depending on the temperature.

In a preferred method, the synthesis gas is cooled in at least three stages.

In order to remove any other pollutants that may be present (furans, sulfur...), a carbon filter 10 (alternatively: gas scrubbing) is connected via a line 106, and preferably a zinc oxide filter (or a doped carbon filter) via a line 107 -Filter for sulfur adsorption) 11, downstream. Synthesis gas that has been completely cleaned in this way is compressed in the compressor 12 via a line 108 to a pressure which is suitable for the hydrogen separation. This pressure is preferably in a range between 10 bar and 25 bar, preferably between 12 bar and 20 bar. Additionally or alternatively, it would also be possible to carry out gas scrubbing

In order to remove hydrogen from other gases from synthesis gas, a PSA (Pressure Swing Adsorption) plant 13 is preferably used. The separated hydrogen passes through a line 40 into an H ₂ compressor 14, where it is compressed to 350 bar or even higher pressures. Compressed hydrogen is ready for further use and leaves the plant along arrow P6.

The tail gas (off-gas) from the PSA plant 13 contains the gases such as CO, CO ₂ , CH ₄ and a small amount of unused H ₂ with a sufficient content of chemical energy. This energy is used to generate water vapor (via a line 15) or to superheat the water vapor (via a line 17).

Line 15 directs part of the tail gas into a steam generator 16 where saturated steam is produced. The condensed water from the condenser 8 is preferably used as the feed water, to which fresh water from a line 83 is mixed via a line 81 and a metering valve 82 . A lot of fresh water (about 1/3 of the feed water) is needed because it is consumed by the reaction with the carbon in reactor 1 for hydrogen production.

With a feed water pump 71, the correct pressure for the steam boiler 16 and the saturated steam produced, or for the entire system 200, is generated. Before entering the boiler 16, the feed water is preheated in the heat exchanger 7 by using the heat from synthesis gas. Both fresh water from line 83 and condensed water from line 81 are processed to the quality required for boiler 16 in appropriate systems, which are not shown here.

The device according to the invention preferably has a water treatment device.

The saturated steam then reaches two heating devices, preferably two regenerators 20 and 21, via a connecting line 18, which is split into two sub-lines 18a and 18b. In these regenerators, the steam is superheated to the required temperature. At the in 1 The device shown has two regenerators 20 and 21 which preferably enable continuous operation of the system.

While the water vapor is being overheated in the regenerator 20, the regenerator 21 is in a heating-up phase, ie it is charged with thermal energy here in particular by the combustion of the second part of the tail gas 17 from the PSA system 13. A large number of valves 22 to 29 are used to control the two regenerators.

The valves 22, 24, 26 and 28 are assigned to the regenerator 20 and the valves 23, 25, 27 and 29 to the regenerator 21. By switching, for example a periodic switching of the valves 22 to 29 shown, the two regenerators 20 and 21 be operated alternately. By utilizing the energy of the tail gas 15 and 17, this energy is fed back into the process in the form of the very highly superheated water vapor through line 19.

In this case, it is possible for the switchover to be controlled by means of a timer, that is to say that a switchover preferably takes place during working operation at predetermined points in time or in predetermined periods of time. Furthermore, it is also possible for a switchover to take place on the basis of other parameters, such as a temperature measurement. In addition, combinations of both controls are also possible.

For example, a time-dependent control can be provided primarily, but it is also checked whether a changeover is also indicated by corresponding temperatures. In addition, it is also possible for a machine operator to be asked to carry out a switchover.

The resulting combustion gases leave the regenerators through a line 30 and reach a drying system 31. There, their sensible heat is used to significantly reduce the water content of the moist raw material that enters the system 200 along the arrow P1. In this way, the water content of the dried raw material that enters the reactor 1 along the arrow P2 is reduced to well below 10%, which means an increase in the efficiency of the entire system 200 . (10% at 50% input)

The utilization of the chemical energy of the tail gas 15 and 17 from the PSA plant 13 and the utilization of the waste heat from the gas cooler 7 for preheating the feed water, together with the drying plant 31 described above, result in a high efficiency of the entire plant 200 and economical hydrogen production. In a preferred method, synthesis gas is admixed, in particular if the amount of tail gas is not sufficient)

Instead of the in 1 shown two regenerators 20 and 21, three or more regenerators can be used to achieve a particularly smooth operation.

Another gas, or a gas mixture, can be supplied to the water vapor in the line 18 along the arrow P5. This can be an excess tail gas from the plant 13, or an amount of exhaust gas which is branched off from the line 30 from the regenerators 20,21. This can also be an external gas that comes from outside the system 200 . In this way, the excess steam in the reactor 1 can be reduced and the efficiency further improved.

It is also possible to optimize the whole process to increase the yield of another by-product such as benzene to further improve economics. If a particularly dry raw material is present, there is no need for the dryer 31. In this case, the waste heat from the exhaust gases in line 30 can be used for other purposes, e.g. for a local heating network.

The waste heat from the condenser 8, along the arrow P7, can also be used, e.g be.

If the raw material shows a very good and clean quality along the arrow P1, it is possible to dispense with one or more downstream cleaning components, such as particle filter 5, cryo-cooler 9, carbon filter 10 and/or ZnO filter 11 Depending on the impurities in the synthesis gas, the order of the components 9, 10, 11 can be changed in order to achieve an optimal result.

For this purpose, a bypass line can be provided, which bypasses one or more parts of the plant. The synthesis gas can be routed via this bypass line by means of valves.

2 shows a detailed representation of a particularly advantageous embodiment of the 1 thermal cracker 6 shown. In order to achieve low energy consumption of the plant, despite very high temperatures in the cracking zone, two interacting regenerator devices and in particular regenerator layers 65 and 66 are preferably used again used by valves 61 to 64.

The reference symbols 65a and 66a each identify the upper or warmer areas/sides of these layers and the reference symbols 65b and 66b each indicate the lower or cooler areas/sides of these layers. These layers can be arranged radially or also axially next to one another.

The raw syngas flows from line 102, through valve 61 and regenerator layer 65 where it is preheated to a very high temperature, preferably well above 800°C. This temperature causes spontaneous thermal cracking of tars and methane. Since the synthesis gas contains a large excess of water vapor, additional amounts of hydrogen are produced. The synthesis gas preferably passes through the above-mentioned layers in succession.

In order to cover the energy requirement for the cracking and the energy losses of the plant 6, a small amount of the synthesis gas is preferably post-combusted, which is why oxygen is preferably supplied along the arrow P4. Instead of oxygen you can also supply air and in particular Inject: An advantage of this approach is lower costs, but a major disadvantage is that the synthesis gas will also contain nitrogen.

Hot cracked synthesis gas preferentially flows through the second regenerator layer 66 so that it is recooled and in particular brought to near entry temperature. The outlet temperature is normally only 5K to 50K above the inlet temperature.

The gas leaves the system through the valve 64 and flows further through the line 103. After a certain time, the action of the two regenerators alternates due to the actuation of the valves 61 to 64.

Instead of the in 2 In addition to the two regenerators 65, 66 shown, three or more regenerators, which are preferably always connected on the hot side, can also be used. This will make it possible to achieve particularly smooth operation, including a rinsing phase.

The control of the crackers 6, or the switching between the regenerator layers 65 and 66 2 runs as a function of time and/or as a function of temperature. Each phase lasts a certain time, Δtc, typically between 2 and 5 minutes.

When this time has expired, the direction of flow is preferably changed by actuating the valves 61 to 64 and a new operating phase starts. During this time Δtc, the temperature at the outlet increases, measured at measuring points 321 or 322. If this temperature exceeds a certain limit value TC1, the valves 61 to 64 are switched over in order to protect the components from overheating. This means that the temperature is preferably the second switching criterion there as well.

In the high-temperature zone above layers 65 and 66, there is a high reaction temperature TC2, which is preferably specified in order to achieve the desired cracking of higher hydrocarbon molecules. The measuring points or temperature measuring devices 323 and 324 measure the temperature in this zone. Since the cracking reactions are endothermic, the temperature decreases in the flow direction and a quantity of oxidizing agent (oxygen, air,...) along the arrow P4 has to be added.

As a result, part of the synthesis gas oxidizes and the necessary high-temperature heat is generated. Depending on the temperature measurements 323 and 324, the valve 325 regulates the amount of oxidant to keep the desired temperature TC2 as stable as possible.

If the system 6 is designed with layers 65 and 66 through which the flow occurs radially, circulation conveyance is preferably provided again, as in the case of the regenerators 20 and 21, in order to control or reduce the thermal stresses in the radial direction. But even with the axial layout of the layers 65 and 66, a small amount of the bed material can preferably be regularly removed from below and reinserted above. Deposits of soot particles are formed in the middle layers of the bed, which can increase the pressure loss and prevent free flow. By circulating the bed material, the soot-containing particles reach the high-temperature zone, where soot disappears again.

3 shows a detailed representation of a particularly advantageous embodiment of the 1 shown cryo-cooler 9. In order to achieve low energy consumption of the system, despite very low temperatures in the cold zone, two interacting regenerator layers 95 and 96 are preferably used again. These layers can consist of gravel, for example.

A large number of valves 91 to 94 are used to control the two regenerators. The large excess of water vapor in the synthesis gas is preferably removed beforehand in the condenser 8, but preferably depending on the temperature and pressure prevailing there. A small amount of residual moisture can still remain, which can cause problems for trouble-free operation in downstream components.

Therefore, the syngas preferably flows from line 105, through valve 91 and regenerator layer 95, where it is cooled to a very low temperature, at least below 0°C or well below 0°C as required. This temperature causes the residual moisture to condense out and the synthesis gas becomes completely dry. Extremely volatile gaseous hydrocarbons such as benzene, toluene, naphthalene, etc. will also condense. It is possible to extract some of these chemicals and reuse them for other processes, which increases the economics of this plant 200.

In order to maintain the low temperatures and to cover the cooling losses of the system 9, a refrigeration system 97 is preferably connected downstream. Cold and/or dried synthesis gas flows through the second regenerator layer 96 so that it is cooled almost back to the inlet temperature. The gas leaves the system through the valve 94 and flows further through the line 106. In this process, cooling and then heating of the synthesis gas preferably takes place first

After a certain time, the effects of the two regenerators change due to the activation of the valves 91 to 94. Instead of the in 3 In addition to the two regenerators 95, 96 shown, three or more regenerators, which are preferably always connected on the cold side, can also be used. This makes it possible to achieve particularly smooth operation, including a rinsing phase.

The control of the cryo-cooler 9, or the switching between the regenerator layers 95 and 96 in 3 takes place preferably according to time and/or according to temperature. Each phase lasts a certain amount of time, Δtcc, typically between 2 and 5 minutes.

As soon as this time has elapsed, the direction of flow is changed by actuating valves 91 to 94 and a new phase of operation begins. During this time Δtcc, the temperature at the outlet falls, measured at the measuring devices or measuring points 331 or 332. If this temperature falls below a certain limit value TCC1, valves 91 to 94 are preferably switched over before the time has expired in order to improve efficiency to keep the system high, or to keep the energy consumption of the cooling unit 97 low. Time and temperature control is therefore preferably carried out here

In the low-temperature zone below layers 95 and 96 there is a very low temperature TCC2, which is specified in order to achieve the desired drying out of the synthesis gas, at the same time as the precipitation of the very volatile residual tar fractions (such as naphthalene). Measuring points 333 and 324 measure the temperature in this zone. In order to cover the heat of condensation, the cooling unit 97 has to extract the resulting heat. Depending on the temperature measurements 333 and 334, the power of the unit 97 is preferably regulated in order to keep the desired temperature TCC2 as stable as possible.

4 shows another preferred embodiment. The tars from line 109 are injected directly into the high temperature zone of regenerators 20,21. During a combustion phase, the injected tars oxidize and contribute to the preheating of the regenerator 20 in 4 . This is particularly advantageous if the amount of energy in the tail gas from line 17 is insufficient.

If the tars are injected during a steam superheating phase, as in the regenerator 21 in 4 , the tars react with the steam. This steam reforming immediately produces additional amounts of H ₂ , along with some CO/CO ₂ , and so reduces the temperature of this gas mixture. In this way, the thermal load on the hot blast slides 28, 29, the line 19 and the high-temperature part of the reactor 1 is significantly reduced with the same energy supply.

By operating the valves 110, 111 it is possible to select in which operating phase of the regenerators 20, 21 the tars are to be injected.

The control or switching of the regenerators 20 and 21 in 4 preferably runs as a function of time and/or temperature. Each heating or vapor phase lasts a certain time, Δth, or Δtd. If only two regenerators are provided, Δth < Δtd since it takes a short time to bring all the valves into the right position.

In this way the supply of the superheated steam is preferably (absolutely) continuous and the rest of the process in the reactor 1 and in the whole plant 200 runs without interruption. If you use three or more regenerators, the heating phase is correspondingly longer, but with a reduced flow. e.g., with three regenerators, one heating phase is slightly shorter than twice the vapor phase: Δth < 2Δtd. In this way one can keep the pressure loss of a heating phase approximately the same as in the vapor phase. Combustion normally takes place at ambient pressure and the vapor phase at elevated pressure.

The second preferred switching criterion is the temperature. During each heating phase, the temperature of the exhaust gas rises, measured at measuring point 310 or 311. If this temperature rises above a predetermined limit temperature TG1, the heating phase ends and returns to the vapor phase. The reason for this is to protect the material from overheating, but also to keep the efficiency of the system high.

For the inside 4 drawn case (regenerator 20 is in the heating phase), the heating phase ends before the time Δth has expired if the temperature at the measuring point 310 has reached the value TG1.

The temperature as a switchover criterion preferably also applies to a vapor phase. During each steam phase, the temperature of the superheated steam falls, measured at the measuring point or with the measuring device 312 or 313. If this temperature falls below a predetermined limit temperature TG2 falls, the vapor phase is preferably ended and activated in the heating phase.

The reason for this is the process in reactor 1. If the steam temperature is too low, the yield of hydrogen will be reduced. For the inside 4 shown case (regenerator 21 in the vapor phase), the vapor phase is terminated before the time .DELTA.td has expired if the temperature at the measuring point 313 has fallen below the value TG2.

Additional temperature measuring points, which are not shown here, can be arranged on the regenerators 20 and 21 in order to check the correct gas distribution or the combustion process.

In order to control or reduce the thermal stresses in the radial directions of the regenerators 20 and 21, a method and corresponding devices as described in the patent are preferred DE 97 44 387 C1 or in the patent application DE 10 2012 023 517 A1 are described, used.

5 shows an alternative to the device 200 from 1 . The energy necessary for steam generation in the boiler 16 does not come from the tail gas but from another external energy source, along the arrow P8. This can again be the same raw material as in 1 , e.g. biomass.

But it can also be another raw material, eg industrial waste, waste gas, etc... In this case, more tail gas will be available for steam superheating in the regenerators 20, 21. If not necessary, the excess tail gas is injected into the saturated steam line 18 along arrow P5. In this way, more H ₂ is produced and the H ₂ yield along the arrow P7 per raw material quantity P1 used will be specifically higher. This has a positive influence on the utilization of the plant 201 and accordingly on the economy. Another alternative is to use an external steam source.

Commissioning and cleaning:

In order to prevent or at least minimize the deposit of the tars, a trace heating device is preferably provided on at least one of the lines 100, 101, 102, 103, preferably on several of these lines and preferably on all of these lines. A trace heating device is preferably also provided on the cyclone 2 and dust filter 5 components and preferably on the valves in the vicinity of the cracker 6, 61 to 64.

Preferably, at least one of these tracer heating devices, preferably several of these tracer heating devices and particularly preferably all of these tracer heating devices is an electrically operated heating device.

As a heat tracing device, an electric wire version is the best solution, but there are other solutions, e.g. steam heating or hot water heating.

The electrical trace heating device is preferably controlled very precisely because the wall temperature of the line must not be too low (intensive condensation of the tar) but also not too high (caking of tar).

Before the plant is started up, the lines and components mentioned are preferably preheated to a temperature between 50.degree. C. and 80.degree. During start-up the synthesis gas temperature increases and therefore the heat tracing power must also increase so that the wall temperature always follows the synthesis gas temperature.

If you have a sufficiently good external insulation of the lines or the components, the power of the trace heating device(s) is preferably greatly reduced or even switched off (at least temporarily) when the nominal operating conditions are reached. The trace heating device is then preferably only used to regulate the wall temperature, ideally around a value in the range of the synthesis gas temperature and particularly preferably in a range of ±5 K of the synthesis gas temperature.

Preferably, the lower part of the reactor 1 is filled with lime, dolomite, old ash (if any) or similar material. In this case, the regenerators 20 and 21 supply only slightly superheated steam, approx. 200°C to 300°C, in order to preheat the empty (without biomass!) reactor 1, cyclone 2, particle filter 5 and cracker 6.

6 shows the most important measuring points and components for the safety and regulation of the gasification device or the reactor 1. A large number of temperature measuring points or temperature measuring devices 300 are provided on the side, which are arranged at different heights of the fuel bed. There are preferably at least four such measuring points, preferably at least eight, and particularly preferably at least ten and preferably twelve.

In a preferred embodiment, these measuring points or measuring devices In are not on top of each other, but arranged around the reactor. In normal working conditions, measured temperatures should drop from bottom to top. If this is not the case, it means that the bed is not flowing evenly, or that there are empty spots in the bed.

In such a case, the carburetor device is controlled in order to change its working mode. Thus, the gasification agents and fuels can be increased through line 19 and/or additional amounts of fuel P2 can be introduced.
In order to achieve a constant capacity of the reactor 1, a further temperature measuring device or measuring point 301 is provided (directly) at the reactor outlet. If the temperature measured there is higher than a target temperature T1, this means that there is not enough fuel in the reactor. In this case, additional quantities can be filled in through P2. In this case, the temperature drops and if a lower target temperature T2 is reached, the further supply of fuel is stopped until the upper target temperature T1 is reached again.

With a rotating rake 303, the introduced fuel is evenly distributed to avoid empty or unevenly filled spots in the bed. The rake is driven by a motor 305 by means of a shaft 304 . The torque on this motor provides information about the fuel levels in reactor 1, which can be used as an alternative method for capacity control. If the torque is less than a given value M1, it means that the rake rotates empty and the amount of fuel is too low. By adding the fuel through P2, the torque increases and as soon as a value M2 is reached, the fuel supply is stopped until the torque value M1 is reached again.

In a preferred method, the conveying capacity of the products to be gasified is therefore controlled and, in particular, regulated as a function of a number of control variables.

In a further preferred embodiment, a drive device is provided which allows the vertical position of the rake 304 to be changed. The vertical position of the rake 303 and/or the shaft 304 can be changed in particular depending on the fuel quality (composition, water content, lumpiness...). This has an influence on the target temperatures T1 and T2, or on the torques M1 and M2.

At the reactor outlet, or at line 100, in particular immediately after the reactor, the composition of the synthesis gas is preferably measured (measuring point 302 in 6 ). This is used to change the input parameters in order to achieve a higher yield of hydrogen.

The device preferably has a measuring device for determining an oxygen content of the synthesis gas.

In addition to the usual components of the synthesis gas (H ₂ , CO, CO ₂ , CH ₄ ...), the oxygen concentration (O ₂ ) is also preferably measured. Oxygen can, for example, get into the reactor through the biomass lock and thus in the synthesis gas.

This is extremely undesirable as it creates oxyhydrogen (a mixture of H ₂ +O ₂ ) which can damage equipment and injure personnel. For this reason, the system immediately goes into an EMERGENCY state if the oxygen concentration has reached a specified value. The supply of reactant through line 19 is stopped (in particular immediately), and nitrogen is preferably injected and/or the bypass lines 111 to 118, shown in FIG 7 .

Only when the oxygen concentration falls well below the limit value can the system be put back into operation. If such a situation occurs again, the system must be shut down until the cause has been found and eliminated.

The exhaust gases, which may also contain some tar from previous operation, are preferably fed into an afterburner chamber 50 (cf. 7 ).
The supply of steam is then preferably stopped and the filling of the reactor 1 is started. When the reactor 1 is sufficiently filled with the fuel, the supply of steam is preferably started again, so that the first amounts of synthesis gas are formed.

During start-up, the entire system 200 is preferably not switched on immediately, but one part after the other. For this reason, at least two, preferably four or even more bypass lines are preferably provided. In 7 Four such lines, 111, 112, 116 and 118, along with a manifold 120, are shown.

The by-pass valves 351, 352, 356 and 358 are preferably used for this purpose. These valves are preferably designed as three-way valves (alternatively, two two-way valves with a coupled drive can be used). At the beginning, by actuating the valve 351, the by-pass line 111 is opened so that the synthesis gas cannot flow any further in the direction of the particle filter 5.

If the temperature and the operation of the cyclone 2 are correct, the by-pass line 112 is opened by actuating the valve 352. Then the line 111 is closed so that the entire quantity of synthesis gas can flow through the particle filter 5 and the Line 112 flows. This mode of operation is continued until the last line 118 is opened by actuation of valve 358. As soon as the temperatures, gas quality and pressure of the synthesis gas are correct at this point, the bypass line 118 is preferably closed and the gas flows through the compressor 12 through the PSA system 13. The production of pure hydrogen thus begins .

Via line 120, the qualitatively inferior synthesis gas from by-pass lines 111 to 118 reaches an afterburner chamber 50, where this gas, together with more or less tar residues, is afterburned and the clean exhaust gases are discharged through the chimney 51 into the atmosphere become.

The afterburner chamber 50 can be integrated into the combustion chamber of the boiler 16 in order to utilize the heat developed for steam generation. During start-up, an external fuel, preferably renewable fuel such as biomass, bio-diesel or bio-methane, is preferably used for saturated steam generation in boiler 16 and for steam superheating in regenerators 20 and 21. For the first time when the production of the synthesis gas is fully running, the external fuel is preferably dispensed with.

cleaning

After a shutdown, the system is preferably cleaned and/or prepared for the next phase of operation. First, the reactor 1 is shut down, i.e. there is no more biomass supply and/or no more steam supply. Alternatively, you can fill in lime, dolomite, old ash or similar material instead of biomass. All bypass lines 111 to 118 are preferably open in this phase.

Then you run with a reduced steam supply, with ever lower steam temperature, until about 300°C are reached.

When the biomass is consumed or removed through the ash sluice, cleaning of the plant begins. Slightly superheated steam (200-300°C) flows through the reactor 1 and through the lines 100, 101, 102, 103, through the cyclone 2, particle filter 5 and the cracker 6 and removes any tar that may have deposited.

If necessary, you can add air to the saturated steam and superheat both to 200°C to 300°C. This can burn the stubborn deposits of tar in the pipes. The temperature is preferably monitored, since additional heat is generated. At the end, the steam supply is preferably stopped and the system can cool down.

Depending on the fuel quality, one or more parts of the plant can be left out, such as the cyclone 2, the particle filter 5 or the cracker 6.

If a fuel is used with absolutely no small parts, which does not form any particles when reacting with water vapor, then the particle filter 5 can be dispensed with.

If you charge a fuel that contains no volatile components, the use of crackers 6 may be superfluous.

If you have a sulfur-free fuel, then the ZnO filter 11 is no longer necessary.

All components of the system 200 are necessary to produce a very high quality of hydrogen, such as that required for the fuel cell. If one wants to feed the generated hydrogen into a natural gas pipeline, the quality requirements are not so high and one or more components 9, 10 or 11 can be left out. These components (9, 10, 11) can also be arranged in a different order than that shown.

The applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided they are new compared to the prior art, either individually or in combination. It is also pointed out that the individual figures also describe features which can be advantageous in and of themselves. The person skilled in the art recognizes immediately that a specific feature described in a figure can also be advantageous without adopting further features from this figure. Furthermore, the person skilled in the art recognizes that advantages can also result from a combination of several features shown in individual figures or in different figures.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102014112401 A1 [0079]
• DE 102012111900 A1 [0102]
• DE 102012111894 A1 [0102]
• EP 2928991 A1 [0102]
• EP 0620909 B1 [0146]
• DE 4236619 C2 [0146]
• DE 9744387 C1 [0211]
• DE 102012023517 A1 [0211]

Claims (13)

Process for converting carbon-containing raw materials and in particular biomass into hydrogen, comprising the steps: gasification of the carbon-containing raw materials (2) in a gasifier (1), with heated steam being introduced into the gasifier (1) and used for gasification; Purification of the hydrogen-containing synthesis gas produced during the gasification, with the gasification preferably being an allothermic gasification and the heated steam being preferably used both as a gasifying agent and as a heat transfer medium for the gasification, characterized in that at least two different measuring devices measure a variable that is characteristic of the conversion process is measured and the method is controlled by a control device taking this characteristic variable into account. procedure after claim 1 characterized in that at least one of these characteristic variables is a temperature and in particular a temperature and/or a pressure of the synthesis gas. Method according to at least one of the preceding claims, characterized in that different process parameters are recorded using a large number of measuring devices and/or sensor devices, the recording preferably taking place over a longer period of time. Method according to at least one of the preceding claims, characterized in that a temperature characteristic of the gasification process is measured and in particular that this temperature is measured at at least two different positions of a gasification device Method according to at least one of the preceding claims, characterized in that the measured values and/or process parameters are recorded continuously and/or clocked and in particular are recorded with a time allocation. Method according to the preceding claim, characterized in that n tuples are recorded from a plurality of measured values, in particular with a time assignment. procedure after claim 2 or 5 , characterized in that an evaluation device and/or processor device derives information characteristic of the operation of the device or the method from the measured values and/or data recorded. Method according to at least one of the preceding claims, characterized in that the characteristic variable is selected from a group of variables which include a temperature of the water vapor occurring during gasification, a temperature of the synthesis gas, a pressure of the synthesis gas, a torque of a drive device which conveying biomass to the gasifier, flow rate, pH of the carbonaceous material, and the like. Method according to at least one of the preceding claims, characterized in that the carbon-containing raw materials are fed to the gasification process by means of a conveyor and this conveyor is preferably controlled and in particular regulated on the basis of at least one characteristic variable. Method according to at least one of the preceding claims, characterized in that at least one parameter which is characteristic of a conveyor device for conveying the carbonaceous raw materials is measured. Method according to at least one of the preceding claims, characterized in that characteristic values of the synthesis gas are determined using a large number of measuring devices and the conversion process is controlled on the basis of these values, these values being preferably selected from a group of values which include temperature values, pressure values, moisture levels of the syngas and the like. Device (200) for converting raw materials containing carbon and in particular biomass into hydrogen with a gasification device (1) for gasifying the raw materials containing carbon (2), with a feed device which introduces heated steam into the gasifier (1) in order to use it for gasification and with a cleaning device (5, 6) for cleaning the hydrogen-containing synthesis gas produced during the gasification, the gasification preferably being an allothermic gasification and the heated steam being preferably used both as a gasification medium and as a heat transfer medium for the gasification, characterized in that the Device has at least two different measuring devices, which measure a characteristic of the conversion process variable and a control device before direction taking this characteristic variable into account. Device (200) according to the preceding claim, characterized in that the device (200) has a conveying device which conveys the carbonaceous raw materials into the gasification device (1).

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