Method for producing synthesis gas and device for carrying out said method

Abstract

The invention relates to a method for producing synthesis gas from at least partially biogenic starting materials, comprising pyrolysis of the biogenic starting material at a temperature of 250°C to 700°C, and feeding of the pyrolyzed solids via an intermediate zone to a gasification zone, wherein combustion gases containing at least water and oxygen are passed through the gasification zone at a temperature of 600°C to 1200°C so that the pyrolyzed solids are gasified and gasification gases and ash are formed; feeding the pyrolysis gases and the gasification gases to a reforming zone, where the gas mixture is brought into contact with a catalyst bed at a temperature of 700°C to 1100°C, and synthesis gas is obtained. The invention also relates to a system for carrying out said method.

Description

[0001] Fraunhofer symbol: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0002] 1

[0003] Patent application:

[0004] Method for producing synthesis gas and apparatus for carrying this out

[0005] procedure

[0006] Applicant:

[0007] Fraunhofer Society for the Advancement of Applied Research eV

[0008] The invention relates to a process for producing synthesis gas, in particular hydrogen-rich synthesis gas, especially from at least partially biogenic starting materials, which are first pyrolyzed, wherein the pyrolyzed solids are subsequently gasified. The invention further relates to a device or system for carrying out this process.

[0009] Synthesis gas is typically produced using processes for the gasification of coal or other fossil fuels, in which the starting materials are partially oxidized with oxygen and the addition of steam, producing product gases consisting mainly of carbon monoxide and hydrogen.

[0010] The gasification of organic material is also known; this process begins with pyrolysis of the starting material, producing carbon-rich charcoal and volatile components; the charcoal is then partially combusted. Synthesis gas is then formed from the reaction products via the Boudouard equilibrium.

[0011] In general, gasification serves to convert carbon-containing feedstocks into synthesis gas and a solid gasification residue using a substoichiometrically added oxidizing agent. The oxidizing agent typically used is atmospheric oxygen, pure oxygen, carbon dioxide, or water vapor. However, gasification is primarily used for fossil feedstocks such as hard coal, lignite, coke, peat, petroleum, and wood.

[0012] Gasification of (dried) biomass generally begins at temperatures of 150 °C, with water vapor and oxygen being the first substances released. At higher temperatures, see FhG symbol: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0013] 2

[0014] At these temperatures, the solid components of the biomass are gasified, particularly the lignin and cellulose. Technical biomass gasification is carried out using an oxidizing agent (or gasification agent) without ignition at temperatures of 700 °C to 900 °C. During combustion, primarily carbon monoxide, rather than carbon dioxide, is formed. Other components of the resulting gas include hydrogen, methane, water vapor, and, depending on the type of biomass used, a range of organic substances in varying concentrations. Ash and biochar residue remain as solid residues. By lowering the temperature, a wood gas condensate containing organic components is formed from the resulting process gas. The product gas can then be further oxidized; if gasification is carried out with air, the product gas, which is thereby diluted with nitrogen, is often referred to as low-calorific-value gas (LCV).

[0015] Despite extensive research projects, biomass gasification plants have so far only gained a foothold in the market in isolated cases. In Scandinavia, wood gasification plants are operated to provide heat for district heating networks; this offers advantages due to lower emissions compared to combustion. However, the real advantage of gasification would only become apparent in electricity generation, as significantly higher efficiencies can then be achieved compared to commercially available combustion. This technology, however, is not yet fully developed, particularly because adequate gas purification is not yet available.

[0016] In recent years, the production of usable product gases from biomass has increasingly been carried out by means of intermediate pyrolysis, possibly with an integrated catalytic reforming step (see, for example, WO 2016 / 134794 A1). However, this process does not produce synthesis gas, but rather low-molecular-weight hydrocarbon mixtures as gaseous components.

[0017] German patent DE 10 2008 027 858 A1 describes a process in which carbon-containing fuels are first pyrolyzed and gasified, and the resulting gases are then subjected to exothermic degradation. No synthesis gas is produced in this process either. Fraunhofer designation: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0018] 3

[0019] Fixed-bed gasifiers are predominantly used for biomass gasification, with two technically established processes: co-current gasification and counter-current gasification. In counter-current gasification, the product gas is drawn off in the opposite direction to the fuel feed; the product contains a high proportion of water vapor and organic components. In co-current gasification, the gasifying agent is fed in the same direction as the fuel, causing the resulting product gas to pass through the hot oxidation zone. The organic content in the product gas is significantly reduced compared to counter-current gasification; however, this process is considerably more complex and typically results in a high dust load.

[0020] The state-of-the-art processes therefore have the disadvantage that the gases produced during gasification contain significant impurities and thus require post-treatment before further use. Furthermore, no method for precisely adjusting the hydrogen and / or carbon monoxide content of the synthesis gas has been described. Inhomogeneous feedstocks are also only conditionally suitable as input materials.

[0021] The present invention is therefore based on the objective of improving prior art processes for the gasification of biomass and, in particular, of providing a process and a suitable apparatus for this purpose with which synthesis gas is obtained, especially synthesis gas that can be used without further purification. Further objectives include the production of synthesis gas with an adjustable hydrogen / carbon monoxide ratio and also the production of synthesis gases that can be used in combined heat and power plants or gas turbines, or that can be used as a feedstock for the production of hydrocarbon compounds.

[0022] At least one of these problems is solved by the process for producing synthesis gas and the plant for carrying out this process according to the independent claims. The dependent claims, the following description, and the examples illustrate advantageous further developments. Fraunhofer designation: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0023] 4

[0024] According to a first aspect of the present invention, the process for producing synthesis gas is explained below:

[0025] A process for producing synthesis gas from a carbon-containing feedstock, in particular a feedstock that is at least partially biogenic, first comprises providing the feedstock and a catalyst for reforming the products formed during pyrolysis and / or gasification (i.e., a reforming catalyst). The feedstock is heated in a pyrolysis zone, causing a thermochemical conversion and the formation of solid pyrolysis products and pyrolysis vapors / pyrolysis gases. The solid pyrolysis products (which, within the scope of this invention, are also referred to as pyrolyzed solids) are subsequently fed into a gasification zone, whereby the contact of the supplied combustion gases with the solid pyrolysis products results in combustion and thus (at least at the start of the gasification process) a temperature increase.On the other hand, gasification gases and ash are formed from the solids. The gasification gases and pyrolysis gases are subsequently subjected to reforming, where they come into contact with a bed of the aforementioned catalyst. This reforming process primarily targets the pyrolysis gases, yielding synthesis gas as the main gaseous product. This synthesis gas is then collected (after an optional intermediate gas purification process). Water contained in the gasification gases can, in the case of carbon-based catalysts, increase the catalyst's surface area within the reformer, thus enhancing its effectiveness.

[0026] According to one embodiment of the invention, biogenic or at least partially biogenic materials are used as starting materials, as the process according to the invention can then particularly demonstrate its advantages, especially with regard to sustainability. Often, essentially entirely biogenic materials will be used, particularly with a view to producing bio-based synthesis gas. Furthermore, biogenic starting materials are particularly suitable for the combustion process. In this context, "biogenic" means that the starting material is essentially of "biological or organic origin." [FhG designation: UMSICHT-ATZ - 2018P61706WO 22.09.2025]

[0027] 5. The term therefore does not include materials of chemical-synthetic origin. In particular, the term thus includes starting materials that are essentially formed by plants, animals, or microorganisms. However, non-biogenic material can also be used. In principle, the use of completely non-biogenic materials as starting materials is also conceivable, especially materials with a high ash content, such as plastics, used tires, and the like—particularly non-biogenic materials that are solid at room temperature.

[0028] Biogenic feedstocks can include not only materials such as cellulose-containing materials (especially wood residues, agricultural residues, and straw), industrial biomass residues (especially digestate, brewer's grains, grape pomace, olive pomace, nutshells, or coffee grounds), used cooking fats and animal fats not approved for consumption or feed production, stillage from paper recycling, as well as manure-containing materials and sewage sludge. It goes without saying that mixtures of these materials can also be used as feedstocks, or mixtures of the aforementioned materials with other biogenic or non-biogenic substances. Furthermore, inseparable mixtures of biogenic and non-biogenic materials can also be used, as is the case, for example, with used baby diapers or saliva from paper recycling.

[0029] Finally, polymers that are not considered biogenic can also be used as starting materials. These include, in particular, polyacrylates, polyurethanes, polyesters, polyolefins, and rubber (such as that which is produced in large quantities from used tires). It goes without saying that these substances can also be found mixed with each other or with other substances.

[0030] If only partially biogenic materials are used as starting materials, the weight fraction of the non-biogenic components in the starting material can exceed 5 wt.%, for example, more than 10 wt.% or even more than 25 wt.%. The disadvantage of this is that purely biogenic synthesis gas is no longer produced; however, with the process according to the invention, it is possible to convert any starting materials, and for example, starting materials with FhG mark: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0031] 6

[0032] to use impurities of halogen-containing non-biogenic materials or with a proportion of non-biogenic components that are solid at room temperature, as specified above (for example, partially halogenated polymers).

[0033] According to one embodiment, the starting materials have a dry matter content of at least 50 wt% (or a water content of no more than 50 wt%). However, the water content is often no more than 30 wt%, and particularly no more than 20 wt%. In principle, there is no significant limit regarding the water content; however, from an energy perspective, a lower water content is advantageous, as otherwise too much additional energy is required for water evaporation during the pyrolysis step. The use of not completely dry starting material can also be advantageous, however, since the presence of water vapor in the reforming zone is beneficial for hydrogen formation.

[0034] The biogenic and / or non-biogenic starting materials are subjected to pyrolysis (in particular, the pyrolysis zone of a reactor). Here, under the exclusion of oxygen, or at least substantially so, and at elevated temperatures, the pyrolysis products—namely, pyrolyzed solids, pyrolysis gases, and vaporous pyrolysis products—are formed (as is required by definition for pyrolysis). Hereinafter, pyrolysis gases and vaporous pyrolysis products are usually referred to simply as pyrolysis gases, since similar processes occur with regard to chemical reactivity (for example, in the case of hydrocarbons). The pyrolysis temperatures are, in particular, 250 °C to 700 °C, preferably 300 °C to 600 °C, for example, 400 °C to 550 °C. The beginning of the pyrolysis zone is thus defined by reaching the minimum pyrolysis temperature of 250 °C in the pyrolysis material / starting material.The upper limit of the temperature ranges specified above is essentially determined by the energy efficiency required for pyrolysis and the formation of the desired product spectrum. The end of the pyrolysis zone is defined by the transition of the pyrolysis products into a reactor area where no heating elements are present to provide the pyrolysis temperature. Therefore, heating elements can be provided that supply a higher temperature than the pyrolysis temperature, in particular a temperature at least 50 °C higher, such that a FhG mark: UMSICHT-ATZ - 2018P61706WO 22.09.2025.

[0035] 7. The first reforming of the pyrolysis products takes place, or—due to the absence of heating media—the pyrolysis products are initially cooled before being transferred to a reforming zone or the gasification zone. Finally, the pyrolysis products can also "fall" into the next reactor zone due to gravity. The residence time in the pyrolysis zone ranges from 1 second to 1 hour, particularly from 5 seconds to 30 minutes, for example, from 3 minutes to 10 minutes (the pyrolysis can therefore be rapid or, in particular, intermediate). For the determination of the residence time, reference is made in full to WO 2016 / 134794 A1.

[0036] According to one embodiment, the pyrolysis zone for the process according to the invention can be designed in the manner of a multi-stage screw or rotary kiln reactor. More generally, the pyrolysis zone typically includes conveying means for transporting the feedstock or the pyrolysis product, in particular screw conveyors, spiral conveyors and / or belt conveyors.

[0037] In the process according to the invention, it is essential that the pyrolyzed solids are subsequently fed into a gasification zone. In the gasification zone, the pyrolyzed solids are brought into contact with combustion gases comprising at least oxygen and water. The reaction of the oxygen with the pyrolyzed solids initially produces carbon dioxide, but in particular carbon monoxide; due to the exothermic reaction, the solid material in the gasification zone is successively heated. Due to the prevailing high temperatures during operation (and the typically non-increased or only slightly elevated pressures in the reactor), carbon monoxide is then predominantly formed; the carbon monoxide content of the product mixture does not shift, or does not shift significantly, towards carbon dioxide (Boudouard equilibrium).With the added water, carbon dioxide and hydrogen are formed from the carbon monoxide via the water-gas shift reaction. However, the carbon dioxide formed can react back to carbon monoxide via the Boudouard equilibrium. According to the invention, the reaction temperature in the gasification zone can therefore be regulated by adding oxygen; the reaction temperature can also be regulated (i.e., lowered) by adding water. Fraunhofer designation: UMSICHT-ATZ - 2018P61706WO 22.09.2025.

[0038] 8) and the formation of hydrogen can be specifically controlled. Considering the process starting from the provided biogenic feedstocks, it can be seen that synthesis gas can be produced from carbon-containing biogenic materials via the combined pyrolysis / gasification process, in which the hydrogen content can be specifically adjusted for the respective end application. The combination of pyrolysis and gasification is also advantageous because a standardized feedstock can be supplied to the gasification zone, which would not be the case if the biogenic feedstock were used as the feedstock for the gasification reaction.Furthermore, the properties of the pyrolyzed solids can be adjusted with regard to the gasification reaction (and any pre-reforming that may be carried out) through upstream pyrolysis, so that less tar is formed and a more consistent gas quality can be achieved.

[0039] According to the application, combustion gases are defined as the gases supplied to the gasification zone (i.e., only gases not originating from the pyrolysis zone). These include – as already explained – oxygen and water. Water can be supplied in the form of steam; however, if it is used for cooling purposes, liquid water can also be used, for example. The water does not have to be supplied simultaneously with the oxygen, but can also be dosed separately. This can be advantageously used to adjust the water addition (especially during reaction start-up) to the specific conditions in the gasification zone.The aim is to vary the temperature so that the hydrogen content produced, and thus the hydrogen / carbon monoxide ratio of the gasification gases in the gasification zone or of the synthesis gas formed in the subsequent reforming zone, remains constant at least over a longer period. The required oxygen can be supplied to the gasification zone in the form of pure oxygen, but air or another oxygen-containing gas mixture can also be used. Slightly more moderate temperatures can be expected when using air; when using pure oxygen, a slightly higher proportion of water must generally be supplied as gasification gas, as it is required for cooling the reaction. The water does not necessarily have to be pure water; see also FhG mark: UMSICHT-ATZ - 2018P61706WO 22.09.2025.

[0040] 9

[0041] Process water from the registered process or another process can be used, for example.

[0042] According to one embodiment, the reaction of pyrolyzed solids and combustion gases in the gasification zone preferably takes place at temperatures of 600 to 1200 °C, particularly 650 to 1100 °C, for example 700 to 900 °C. The lower limit has proven to be the value at which the Boudouard equilibrium and the other equilibrium reactions are shifted sufficiently far in the direction of carbon monoxide, with its formation being more strongly supported at 650 °C and particularly at 700 °C.The upper limit is essentially determined by the fact that above certain temperatures the ash formed begins to melt, which is undesirable (however, a temperature just below the ash melting point can be advantageous, especially from an energy point of view, since maximum energy efficiency can then be achieved and the product yield can be increased; according to one embodiment, the temperature in the gasification zone can therefore be chosen to be about 10 to 50 °C below the respective ash melting point for known ashes) or changes in the state of matter can also occur in the solid pyrolysis products that are fed to the gasification zone, since heating these above the coal softening point can lead to undesirable thinning.

[0043] The process according to the invention is usually carried out at atmospheric pressure, typically between 950 and 1080 hPa. The process can also be carried out without problems at lower pressures, since the formation of carbon monoxide should preferentially occur due to the Boudouard equilibrium. The process is also fundamentally viable at higher pressures, particularly if a certain amount of carbon dioxide in the product gas is acceptable.

[0044] A further essential process step is the feeding of the gasification gases and the pyrolysis gases into a reforming zone. At the latest in the reforming zone, the gasification gases and pyrolysis gases are mixed. As mentioned at the beginning, reforming takes place in the reforming zone, particularly of the gases formed during pyrolysis, through contact with a bed of the provided (often carbon-based) catalyst. Long-chain hydrocarbons are formed on the surface of the catalyst. [FhG symbol: UMSICHT-ATZ - 2018P61706WO 22.09.2025]

[0045] Ten percent of the gas mixture is cracked into permanent gases, and unwanted substances such as tars are also destroyed. Finally, dust filtration (especially of the dusts formed in the gasification zone) takes place, so that tar- and dust-free synthesis gas is obtained at the end of the reforming zone.

[0046] According to current understanding, in the reforming zone, the hydrocarbon compounds contained in the pyrolysis gases (which are often also oxygen-containing) are adsorbed onto the surface of the catalyst and converted there into low-molecular-weight molecules, especially diatomic to pentatomic molecules, particularly hydrogen, but also methane, and, through coking reactions, into carbon. Catalysts with particularly large surface areas are therefore advantageous. In these processes, in addition to the organic compounds from the pyrolysis gases, the water-gas shift reaction plays a crucial role, enabling accelerated hydrogen production through the catalyst (the water can originate from the moist feedstocks of the pyrolysis, but is primarily supplied via the combustion zone).

[0047] The hydrogen content of the synthesis gas produced can be controlled by adjusting the residence time and quantity of the added catalyst on the one hand, and the amount of water supplied to the reforming zone on the other. According to the invention, it has been found that if the catalyst quantity is too low or the catalyst residence time in the reforming zone is too long, the hydrogen content and quantity in the synthesis gas produced decreases (currently, based on a very rough estimate, it can be assumed that a complete exchange of the catalyst should occur after approximately 24 to 120 hours). With fresh catalyst and a sufficiently large quantity, an adequate amount of catalyst surface is therefore available to promote the formation of hydrogen from the reactants. The decreasing activity of the catalyst during longer residence times can, however, be compensated for by increasing the amount of water supplied.

[0048] According to the invention, a carbon-based catalyst or a mineral catalyst, in particular a metal oxide, a zeolite or an aluminosilicate, carbonates such as dolomite and, more generally, one of the catalysts known to those skilled in the art, which are suitable for cracking hydrocarbons, can be used as a catalyst. Fraunhofer mark: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0049] 1.1 In particular, the FCC process can be used. The carbon-based catalyst can be selected from the group consisting of activated carbon, activated coal, and mixtures of the aforementioned substances. Freshly formed pyrolyzed solids are also suitable as catalysts or in mixtures with one or more of the aforementioned catalysts; however, as a rule, the carbon-based catalyst, the mineral catalyst, or the cracking catalyst will be added separately. Suitable metal oxides include, in particular, transition metal oxides such as iron oxide (e.g., Fe₂O₃ or FeO) or FeSiO₃, iron oxide-containing mixtures, or iron oxide-containing waste products, and, in addition to iron oxides, oxides of earlier transition metals (up to group 6) such as vanadium or chromium oxides.It goes without saying that mixtures of metal oxides and the aforementioned carbon-based and / or mineral catalysts can also be used. The catalyst can either be added directly to the reforming zone or added together with the starting material in bulk (which is particularly straightforward with mineral catalysts such as zeolites, iron oxides, or dolomite), possibly also as a precursor of the reforming catalyst.

[0050] The temperature in the reforming zone is typically between 700 °C and 1100 °C, particularly between 800 and 950 °C, for example, 850 and 900 °C. The lower limit is essential to ensure the most complete possible cracking of long-chain and / or oxygen-containing hydrocarbon compounds and to prevent the degradation of synthesis gas via chemical equilibria. The upper limit is primarily determined by the energy efficiency of the process. Furthermore, it is essential that, according to current scientific understanding, all relevant reactions occurring in the reforming zone are endothermic. These include, in particular, the formation of CO via the Boudouard equilibrium, the formation of CO and hydrogen via the heterogeneous water-gas reaction, and the formation of CO and hydrogen via the steam reforming of methane or higher hydrocarbons.In addition, tar cracking is also generally an endothermic reaction. To achieve the aforementioned temperatures in the reforming zone, separate heating of the reforming zone is required, for example by a second heating medium, unless gasification is exceptionally used (see FhG reference: UMSICHT-ATZ - 2018P61706WO 22.09.2025).

[0051] 12. It can be controlled so that energy can be supplied directly via the gasification zone. If the temperatures in the reforming zone are too low, the exothermic homogeneous water-gas reaction and the exothermic reaction of hydrogen with carbon to form methane result in an undesirable consumption of hydrogen and carbon monoxide with regard to the production of synthesis gas.

[0052] From a process flow perspective, an important aspect is the transition between the different zones. More precisely, there is an intermediate zone between the pyrolysis zone and the gasification zone. This intermediate zone can either be the reforming zone; however, it is also possible that a pre-reforming zone (hereinafter also referred to as the first reforming zone) exists between the pyrolysis zone and the gasification zone, and that the essentially pre-reformed pyrolysis gases and the gases from the gasification zone are fed to the reforming zone via or from the pre-reforming zone (in principle, gasification gases and gases leaving the pre-reforming zone can also be fed separately to the reforming zone; however, for efficiency reasons, the gases from the pre-reforming zone and the gasification zone are fed to the reforming zone together).Finally, it is also conceivable that between the pyrolysis zone and the gasification zone there is essentially only an intermediate zone through which the gasification gases and the pyrolysis gases are fed to the reforming zone (without any significant pre-reforming taking place).

[0053] The variant with a pre-reforming zone is particularly relevant because the gasification zone begins at the point of oxygen supply and ends where no more oxygen is available for reaction. Accordingly, above the end of the gasification zone, there is typically a zone containing pyrolyzed solids that are successively fed into the gasification zone. However, in this zone, pyrolysis of starting materials (as in the pyrolysis zone) and gasification of pyrolyzed solids do not occur, or only to a very limited extent. Instead, as the name of the zone clearly indicates, pre-reforming takes place.In fact, the temperature is higher than the temperature of the pyrolysis zone, at least in the area of ​​the pre-reforming zone following the gasification zone, especially since heat convection from the gasification zone into the intermediate zone will be observed (frequently FhG symbol: UMSICHT-ATZ - 2018P61706WO 22.09.2025.

[0054] 13. The temperature of the gasification zone should actually be chosen to be at least 100 °C higher than that of the pyrolysis zone, as this allows for effective heat convection; typically, regardless of this, the temperature of the pyrolysis zone is often a maximum of 600 °C and that of the gasification zone at least 700 °C to achieve good heat convection. Additionally, heating devices can be arranged in the pre-reforming zone (especially in the half of the pre-reforming zone facing the pyrolysis zone) to provide the pre-reforming temperature. Due to this higher temperature, reforming reactions can then also take place in the intermediate zone designed as the pre-reforming zone, and in particular, longer-chain hydrocarbons can be broken down and tars destroyed.

[0055] Pre-reforming in the pre-reforming zone typically takes place at a temperature of 500 to 900 °C, particularly 550 to 800 °C, for example, 600 to 650 °C. The lower limit is primarily determined by the fact that significant hydrocarbon cleavage and tar cracking only begin above this temperature. The upper limit is primarily due to economic reasons. The pre-reforming temperature is higher than that of the pyrolysis zone, usually at least 50 °C higher. Typically, the pre-reforming zone temperature is not uniform across the entire zone, as it is usually higher in the area adjacent to the gasification boundary than in the area adjacent to the pyrolysis zone due to heat convection (even if a heating device is installed in the pre-reforming zone), but lower than the temperature of the gasification zone.

[0056] The process according to the invention can therefore be summarized as follows: First, a biogenic starting material is pyrolyzed in a pyrolysis zone, essentially in the absence of oxygen, at 250 °C to 700 °C with a residence time of 1 second to 1 hour (step A). ​​The pyrolyzed solids formed are fed via an intermediate zone (in which, as explained above, reforming reactions may but do not necessarily have to take place) to a gasification zone (step B). In the gasification zone, the pyrolyzed solids are gasified at a temperature of 600 to 1200 °C, with combustion gases containing at least water and oxygen being introduced into the gasification zone. Fraunhofer designation: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0057] 14 are supplied and these combustion gases are passed through the gasification zone in the opposite direction to the supply direction of the pyrolyzed solids (i.e., countercurrently) (step C). The gasification gases formed in step C and the pyrolysis gases formed in step A (which, according to the application, also include any pre-reformed pyrolysis gases in the intermediate zone) are supplied to a reforming zone, whereby the mixing of the pyrolysis gases and the gasification gases can only take place in the reforming zone (especially if the intermediate zone is simultaneously the reforming zone) but can also take place in an intermediate zone designed as a pre-reforming zone or an intermediate zone without pre-reforming (step D).The gas mixture fed to the reforming zone according to step D is contacted with a catalyst bed in the reforming zone at 700 to 1100 °C, yielding the synthesis gas mixture (step E), which can then be collected in a suitable manner for further use (step F). The methods for such collection are known to those skilled in the art. The specific temperatures to be selected depend on the feedstocks and – as has been indicated, for example, with regard to the ash formed – also on the products formed from them. In this respect, the temperature ranges for all three temperatures mentioned above are relatively large; however, it can be stated that the temperature of the gasification zone – particularly if gasification can be carried out at relatively high temperatures due to high ash melting points – can be higher than that of the reforming zone; but it can also be the same or slightly lower.The temperature of the reforming zone and the pre-reforming zone is typically higher than that of the pyrolysis zone. Comparing the temperature in the reforming zone with that of any pre-reforming zone, the temperature of the reforming zone is typically higher or essentially the same.

[0058] According to one embodiment, the intermediate zone between the pyrolysis zone and the gasification zone can therefore be a pre-reforming zone. The pre-reforming zone is then typically completely filled with the pyrolyzed solid in a horizontal cross-sectional area, wherein – due to the increased temperature compared to the pyrolysis zone (500 to 900 °C, preferably 550 to 800 °C, for example 600 to 650 °C) – the gases and vapors formed during pyrolysis react with the FhG symbols: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0059] In the 15 pyrolyzed solids, reforming takes place, allowing long-chain hydrocarbons and the like to be "crashed" at this early stage of the process sequence (and aromatic compounds to be broken down at higher temperatures). This advantageously reduces the amount of catalyst required in the subsequent reforming step (step E), thus making the process more efficient. Furthermore, depending on the starting material used, gases such as H₂S or ammonia can be formed in the pyrolysis step. These gases are catalyst poisons for the catalysts used in the subsequent reforming step that accelerate hydrogen production (e.g., metal oxides such as iron oxides, which catalyze the hydrogen shift reaction).The formation of these substances can be at least reduced by appropriate design of the pyrolysis and pre-reforming zones (especially by selecting temperatures in the "preferred ranges"), so that the sulfur and nitrogen compounds can be removed via the gasification ash.

[0060] As an alternative to complete filling with the pyrolyzed solid, a complete filling with pyrolyzed solid on the one hand and reforming catalyst on the other is also possible; however, this process is more complex, particularly because the catalyst must be added together with the starting materials or via a separate inlet to the pre-reforming zone, and the catalyst costs are higher than those for the pyrolyzed solid. The mean residence time of the vapors originating from the pyrolysis zone in an intermediate zone designed as a pre-reforming zone is preferably 10, so that pre-reforming can occur to a reasonable extent. !The time between s and 3 minutes, in particular between 0.1 and 20 seconds, for example between 0.5 and 8 seconds, is independent of this. The fully filled volume of the pre-reforming zone is, in particular, between 25 and 65%, preferably 40 to 60%, of the fully filled volume of the reforming zone and / or between 25 and 65%, preferably 40 to 60%, of the fully filled volume of the gasification zone. Typically, with these volume ratios, on the one hand, a sensible reduction of the pressure on the reforming zone can be achieved, and on the other hand, the heat supplied from the gasification zone to the pre-reforming zone via heat convection can typically be utilized very effectively at such a fill level. Typically, this is associated with the following Fraunhofer symbol: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0061] 16

[0062] The volume ratios mean that the residence times of the pyrolysis vapors in the pre-reforming zone specified above can also be achieved.

[0063] According to a variant of the embodiment described above, the intermediate zone between the pyrolysis zone and the gasification zone is the reforming zone (it is therefore not "only" a pre-reforming zone as described above). In this case, it is not strictly necessary to supply a catalyst for reforming to the reforming zone via a corresponding inlet; the pyrolyzed solid can also serve exclusively as the catalyst (as described in principle in WO 2016 / 134794 A1, to which full reference is made in this regard), which is then supplied directly from the pyrolysis zone (the latter variant is – as already explained above – particularly economical). However, a separate catalyst can – as explained above – very advantageously influence the formation reactions for hydrogen and carbon monoxide.A separate catalyst or a precursor for a catalyst can already be supplied via the feed of the starting material to the pyrolysis zone (i.e., a catalyst that is not first formed from biogenic starting material in the pyrolysis zone).

[0064] This variant of the process has the advantage of being particularly uncomplicated and easy to implement. In the simplest case, a tubular reactor can be used, into which the biogenic feedstock is fed from one side and the combustion gases are fed in the opposite direction from the other side. The synthesis gas produced can then be discharged in the intermediate zone.

[0065] According to a further embodiment, the pyrolyzed solids are fed to the gasification zone (i.e., step D) such that the feed direction includes a component pointing in the direction of gravity. In particular, the feed direction is essentially in the direction of gravity, which can be achieved, for example, by ensuring that the reactor area in which gasification takes place is essentially vertically oriented (i.e., has a maximum deviation of 20° from the vertical). As explained, the combustion gases are fed in the opposite direction to the feed direction of the pyrolyzed solids. Fraunhofer registration number: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0066] 17

[0067] Combustion gases can therefore be supplied, in particular, via the lower end of the gasification zone (which is opposite the upper end through which the pyrolyzed solids are fed). This can be done, for example, via one or more nozzles (where the water and oxygen components can also be supplied separately), with the nozzles (or more generally, the gas inlet(s)) opening directly into the gasification zone; however, they can also be arranged downstream of the gasification zone and, for example, open into the discharge device, which is intended for the ash formed in the gasification zone and / or – in the case of short residence times of the pyrolyzed solids in the gasification zone – for pyrolyzed solids that have not been completely gasified. This is therefore a counterflow gasifier. Of course, the combustion gases can also be supplied to the gasification zone or the aforementioned discharge device in other ways.

[0068] Typically, the gasification zone is completely filled, at least in part, with the pyrolyzed solid or the resulting ash in a direction perpendicular to the feed direction of the pyrolyzed solids (i.e., essentially horizontally). This ensures that the oxygen required for the gasification reaction reacts completely with the pyrolyzed solid, because it must not only pass over it but completely penetrate it, so that (in an essentially vertically oriented gasification zone) a boundary for the gasification reaction (or gasification boundary) is formed that is essentially horizontal.

[0069] It goes without saying that for straightforward process control, a region typically exists above this somewhat sharp boundary where (not yet gasified) pyrolyzed solid is present. Otherwise, it could not be ruled out that oxygen would penetrate into the pyrolysis zone and / or a downstream reforming zone in certain quantities. This would have the disadvantage that, due to complete oxidation (because the combustion gas is then no longer substoichiometric), the carbon dioxide content would rise prematurely, resulting in less product gas being formed; furthermore, the penetration of the combustion gas into the pyrolysis zone is unfavorable because oxidation processes would then begin there, and the temperature in the pyrolysis zone would only be [FhG mark: UMSICHT-ATZ - 2018P61706WO 22.09.2025]

[0070] 18 is difficult to control or could rise uncontrollably.

[0071] Unlike oxygen, the water contained in the combustion gas does not necessarily have to be completely consumed in the gasification zone. On the contrary, the role of water is not limited to providing any necessary cooling of the gasification zone; often, more water is supplied than is required as a reactant in the gasification zone to ensure a higher water content in the reforming zone, which in turn has a beneficial effect on the hydrogen content of the synthesis gas produced. Furthermore, the water vapor can also activate the catalyst present as a packed bed in the reforming zone. In principle, particularly during batch operation in the reforming zone, a decreasing catalyst activity in the reforming zone (which, according to the patent application, is a consumption catalyst) can also be compensated for by successively increasing the proportion of water supplied to the gasification zone.

[0072] According to a further embodiment of the process according to the invention, the intermediate zone located between the pyrolysis zone and the gasification zone can also be at least partially completely filled with the pyrolyzed solids, perpendicular to the feed direction of the pyrolyzed solids. This results in particularly close contact between the gaseous or vaporous reactants and the solids, since the gaseous or vaporous reactants cannot simply pass over the solids but must penetrate them. Therefore, the discharge of the pyrolysis gases, or the reformed or pre-reformed pyrolysis gases, is often provided in the intermediate zone of the reactor.This has the advantage that, on the one hand, the penetration of the pyrolyzed solids with the aforementioned gases / vapors can be particularly successful; on the other hand, dusts originating from the gasification zone are filtered in the area of ​​the pre-reforming zone located between the gas discharge and the gasification limit, so that a significant reduction in dust load can be advantageously achieved by discharge slightly above the gasification limit.

[0073] According to a further embodiment of the method according to the invention, the reforming zone (this applies to all embodiments described above) is also located FhG mark: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0074] 19. Perpendicular to the feed direction of the gas mixture (from pyrolysis gases and gasification gases), the catalyst is at least partially completely filled. Here again, the advantage lies in the realization of an intimate reaction of the reactants, as already explained in more detail above.

[0075] The process according to the invention, described in more detail above, thus combines a whole series of advantages. Firstly, a wide variety of feedstocks, particularly biogenic ones, especially those with up to 50 wt% water content, particularly up to 30 wt% water content, and most preferably up to 20 wt% water content, can be used to produce synthesis gas with a tailored hydrogen / carbon monoxide ratio. There is not just one, but several adjustable parameters by which the hydrogen content can be increased: firstly, by the amount of water supplied (or the moisture content of the feedstock), and secondly, by the amount and residence time of the catalyst used in the reforming zone. The relative ratio between carbon monoxide and hydrogen can also be influenced by the temperature control during the reforming step.The carbon monoxide content can also be easily varied using the method according to the invention, as explained above.

[0076] The hydrogen content achievable according to the invention is significantly higher than that of technically established fixed-bed gasification processes (where the hydrogen content is 10 to 20 vol.% and the carbon monoxide content is 18 to 30 vol.%). By combining pyrolysis, combustion, and reforming, it is also possible to produce synthesis gas from biomaterials that is both tar-free and free of polycyclic aromatic hydrocarbons (PAHs). In many cases, it is even possible to produce a gas that contains no hydrocarbons that are liquid at room temperature (i.e., that the content of hydrocarbons that are liquid at room temperature is less than 0.2 vol.%, and in particular even less than 0.02 vol.% as measured by gas chromatography). The synthesis gas produced according to the invention can therefore be used extremely flexibly, for example, in combined heat and power plants and for gas turbines, but also as a feedstock for the production of a wide variety of hydrocarbons.Examples include classic subsequent syntheses such as oxo synthesis (hydrogen / carbon monoxide approx. 1 : 1), Fischer-Tropsch synthesis and dimethyl ether synthesis (hydrogen / carbon). [FhG symbol: UMSICHT-ATZ - 2018P61706WO 22.09.2025.]

[0077] 20 monoxide (approx. 2:1) or methanol synthesis (hydrogen / carbon monoxide approx. 2:1 to 3:1), for which tailored synthesis gases can be produced by controlling the ratio according to the invention. Maximizing the hydrogen content can also serve as an alternative, sustainable source of hydrogen and its economical use.

[0078] The process according to the invention thus overcomes the disadvantages of prior art gasification processes, which are limited to a narrow range of fuels and typically contain high proportions of tars and polycyclic aromatic hydrocarbons. The process according to the invention can be scaled up particularly well and used for a wide variety of different biogenic feedstocks, making it possible to implement small, decentralized plants as well as very large-scale plants.

[0079] According to a second aspect, the present invention relates to a plant suitable for carrying out the above-described process for the production of synthesis gas.

[0080] An apparatus according to the invention comprises a pyrolysis zone for the thermal treatment of a feedstock, wherein means are provided to enable the pyrolysis to take place in the absence of oxygen. In particular, this can be achieved by providing a pressure-tight inlet for supplying the feedstock. To provide the temperatures required for the pyrolysis (in particular 250 °C to 700 °C), the pyrolysis zone comprises at least one first heating device with which the feedstock or the pyrolysis zone can be heated. The heating device can in particular be arranged in the area of ​​the casing of the reactor section of the pyrolysis zone; however, it is also conceivable to additionally or alternatively provide heating media inside the pyrolysis zone, for example heating lances or heat transfer fluids, which are supplied to the pyrolysis zone together with the feedstock.Typically, the pyrolysis zone of the system according to the invention also includes means for mixing the starting material to be pyrolyzed. For example, the pyrolysis zone of the system or reactor can be designed like an extruder. In this case, the extruder not only mixes the starting materials; it also causes the starting material to be pyrolyzed. [FhG mark: UMSICHT-ATZ - 2018P61706WO 22.09.2025.]

[0081] 21, or the already fully or partially pyrolyzed feedstocks are moved towards the gasification zone. However, the pyrolysis zone can also be oriented more vertically, so that the movement of the material within the pyrolysis zone is primarily driven by gravity. Mixing of the material can then be achieved by mixing elements located on the inner surface of the pyrolysis reactor or the pyrolysis zone.

[0082] The system further comprises a gasification zone with at least one first metering device for supplying water (for example, water vapor or liquid) and oxygen (in particular, pure oxygen or atmospheric oxygen), and with a discharge device for solid gasification products (in particular, ash). According to one embodiment, two or more metering devices (for example, nozzles) may also be provided, for example, a first metering device for supplying oxygen and a second metering device for supplying water. The at least one first metering device will typically be located in the region of the lower end or at the lower end of the gasification zone of the reactor (i.e., in the region of the gasification zone where the ash is also discharged).Alternatively, the dosing device can also be arranged downstream of the lower end, for example in the discharge device. The system according to the invention typically does not have a heating device in the gasification zone, since sufficient heat is generated by the gasification reaction. On the contrary, a cooling device is generally required, whereby cooling preferably takes place via water supplied to the gasification zone, especially since this is also advantageous for the formation of hydrogen.

[0083] An intermediate zone exists between the pyrolysis zone and the gasification zone in the reactor or plant. This intermediate zone can be configured, in particular, to include or consist of an area into which the solid pyrolysis products from the pyrolysis zone can fall into the gasification zone (especially in the case of a substantially horizontally oriented pyrolysis section of the reactor). Alternatively, the solid pyrolysis products can also be conveyed from the pyrolysis zone to the intermediate zone in another way (for example, in a horizontal or substantially horizontal direction). The means of conveyance for this purpose are known to those skilled in the art. Typically, the intermediate zone includes (or consists of) an area in which... [FhG mark: UMSICHT-ATZ - 2018P61706WO 22.09.2025]

[0084] 22 Neither the lower temperatures of the pyrolysis zone nor the relatively high temperatures of the gasification zone predominate. This area can be filled with solid pyrolysis products or be partially filled (in the case of a substantially vertical orientation of the intermediate zone, the lower part of the intermediate zone, in particular, can be filled); in extreme cases, however, it can also be empty – especially if, as explained in the description of the process according to the invention, the area located above the gasification limit with (not yet gasified) pyrolyzed solid is reduced to a minimum. Accordingly, the intermediate zone can be a pre-reforming zone or the reforming zone; however, it can also simply be an area in which essentially the pyrolysis gases formed and the gasification gases formed are fed to a further reactor stage of the plant.If the intermediate zone is a pre-reforming zone or the reforming zone, it typically also contains secondary heating elements, unless heat convection from the gasification zone is sufficient for the reforming reactions. From the above explanation, it follows that the reactor's reforming zone can be part of the intermediate zone; however, it can also constitute the entire intermediate zone. Furthermore, the plant can have a "first" and a "second" reforming zone: the "first" zone being a pre-reforming zone located within the intermediate zone, where pre-reforming takes place, and the "second" zone being the actual reforming zone, to which the gases to be reformed are supplied from the pre-reforming zone via a gas supply line and which contains a reforming catalyst.Finally, the reforming zone can be spatially "extracted" from a continuous area between the reactor's pyrolysis zone and gasification zone; in this case, the intermediate zone is typically not filled, or only minimally filled, with (ungasified) pyrolyzed solid and contains a gas supply line to this reforming zone, as described above. If the intermediate zone includes a pre-reforming zone, the gas discharge to the reforming zone is typically located in the area filled with the pyrolyzed solid. The same applies if the intermediate zone is the only zone where reforming takes place; then, the discharge device for the resulting product gas is also located in the area of ​​the intermediate zone filled with the pyrolyzed solid. Typically, this discharge device is...The gas discharge to the reforming zone is not located at the lowest end of the filled area of ​​the intermediate zone. Fraunhofer symbol: UMSICHT-ATZ - 2018P61706WO 22.09.2025.

[0085] 23, but rather slightly above it (since then – as explained above in the process – a reduction of the dust load from the gasification zone can occur through the “filtering effect” of the ungasified pyrolyzed solid). Slightly above it therefore means, for example, in the lower third of the filled area of ​​the intermediate zone, but not in the lowest tenth of the filled area of ​​the intermediate zone. The intermediate zone may (especially if it is the only zone of the reactor in which reforming takes place) have a device for supplying solids (for example, for supplying consumable catalyst for the reforming reaction). However, as explained in the process according to the invention, such a supply is typically not necessary, so the intermediate zone then only has (i) an area or inlet in which solids and gases from the pyrolysis zone are supplied, (ii) an area or inlet in which solids and gases from the pyrolysis zone are supplied.Outlet in which pyrolysis gases and gasification gases are discharged to a reforming zone or an area or outlet for the discharge of the synthesis gas obtained after reforming and (iii) finally adjoins an area in which gasification gases are typically introduced into the intermediate zone against the direction of gravity.

[0086] According to one embodiment, the intermediate zone and / or the gasification zone and / or the reforming zone is oriented substantially vertically. "Substantially vertically" here means that the respective zones can be tilted by up to 20° relative to the vertical (i.e., the direction of gravity). The gasification zone is preferably oriented substantially vertically because the pyrolyzed solid to be gasified can then migrate from top to bottom through the zone and completely fill it, allowing the countercurrently flowing combustion gases to pass completely through it and resulting in substantially complete gasification of the pyrolyzed solids (though this is not mandatory). Similarly, in the reforming zone of the reactor, the gases to be reformed are guided from top to bottom (or, alternatively, from bottom to top) through the catalyst bed.Here too, it is essential that the gases to be reformed flow through the entire surface of the catalyst bed and not just over it. Since the catalyst is a consumable catalyst, it is usually replenished successively and the spent catalyst is carried downwards, so that, overall, a mere passing over it by a vertical flow is not sufficient. (FhG symbol: UMSICHT-ATZ - 2018P61706WO 22.09.2025.)

[0087] 24

[0088] An arrangement that is either horizontal or substantially vertical can be prevented. Particularly in batch operation, the fact that the catalyst is a consumable catalyst leads to fluctuating fill levels in the reforming reactor or reforming zone. This aspect plays a less significant role in continuous operation; in principle, an orientation with more horizontal components would also be conceivable here; however, even in this case, a substantially vertical orientation is preferred.

[0089] Finally, the same principles regarding vertical or substantially vertical orientation apply to the intermediate zone, at least when it is a pre-reforming zone, as to the reforming zone, with the difference that the solid contained therein essentially comprises or consists of the pyrolyzed solid, which in turn is supplied from the pyrolysis zone and—in order to enable substantially full-surface flow of the pyrolysis gases through the solids—is therefore advantageously also oriented substantially vertically. If no reforming takes place in the intermediate zone, however, its orientation can be arbitrary.

[0090] According to an advantageous embodiment, at least the reforming zone and the gasification zone are essentially vertically oriented; according to a further advantageous embodiment, all three of the aforementioned zones are essentially vertically oriented.

[0091] The present invention will be explained in more detail below with reference to drawings, exemplary embodiments and reactor variants or plant variants, without thereby limiting the generality of what has been explained above.

[0092] According to a first variant, which is shown schematically in Figure 1, the plant according to the application has a substantially horizontally arranged pyrolysis zone, a substantially vertically oriented gasification zone, a substantially vertically oriented reforming zone, and a substantially vertically oriented intermediate zone. The pyrolysis zone 1 has a screw conveyor 11, a heating device 12, and a device for feeding the feed material 14. As can be seen from Figure 1, not only the gasification zone 3 but also the intermediate zone 2 is completely filled with material; it transitions into the gasification zone 3. Fraunhofer designation: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0093] 25

[0094] Intermediate zone 2 is configured here as pre-reforming zone 2a. According to this variant, the portion of the screw conveyor 11 located in the area of ​​the second heating unit 18 is already situated within pre-reforming zone 2 / 2a. The heating unit 18 allows for a temperature higher than the pyrolysis temperature, thus enabling reforming reactions. In the portion of intermediate zone 2 located below the screw conveyor 11, which is filled from above with pyrolyzed and partially reformed solid material via an outlet 15, heat is supplied by convection from gasification zone 3.The gasification zone 3 contains, in its lower region slightly above the lower end 30 of the gasification zone, two feed devices 31, 32 for the combustion gases (oxygen and water; the latter preferably in liquid form); the upper end of the gasification zone is formed here by the dashed line of the pre-reforming zone 2a. At the lower end 30, the discharge device 33 for ash and, optionally, ungasified or only partially gasified material is located. The intermediate zone 2 contains an outlet 25 in its lower region, through which the gasification gases and the pre-reformed pyrolysis gases are fed to the reforming zone 4 or the reforming reactor 4 via a feed line 26. The feed of these gases takes place in the region that is not filled with the reforming catalyst. The lower part of the reforming reactor 4 is completely filled with a catalyst bed 40.Heating devices 41 and 42 are arranged laterally in the reforming zone to provide the elevated temperature required for reforming. Synthesis gas is drawn off via an outlet 45 located in the lower part of the reforming zone or reforming reactor 4. This outlet receives the gases formed either unchanged from the preceding zones or generated by the reaction with the reforming catalyst, which occurs when the gases supplied to the reforming zone are passed from top to bottom through the packed bed. Not shown here is an inlet for the reforming catalyst located above the reforming reactor 4 and an outlet for spent reforming catalyst located at the lower end of the reforming reactor 4.

[0095] An exemplary procedure that can be carried out with the device according to the first variant can be described as follows: Fraunhofer designation: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0096] 26

[0097] First, the feedstock is thermochemically converted in a pyrolysis step in a substantially horizontal tube (for example, by means of screws arranged on an axially guided shaft) under exclusion of air and at a temperature of approximately 500 °C applied externally via a heating device. The solids remain in the tube for a residence time of, for example, 10 to 15 minutes (this is therefore an intermediate pyrolysis). New feedstock can be continuously or periodically added, and pyrolyzed material can be fed to the subsequent zones. The resulting pyrolyzed solids can be transferred to a further reactor vessel and there treated with combustion gases (e.g., a water vapor-air mixture or a water vapor-oxygen mixture, or via separate feeding devices, such as nozzles, with water on one side and air or oxygen on the other).This results in at least a partial conversion of the pyrolyzed solid to gaseous products and ash, producing a hydrogen-rich synthesis gas. The targeted injection of oxygen leads to the formation of carbon monoxide through oxidation. The desired stoichiometric ratio of hydrogen to carbon monoxide can be adjusted by varying the ratio of oxygen to water supplied. The hydrogen content can be varied in the different stages of the reactor by controlling the temperature and the water-gas shift reaction. The process can be carried out continuously or periodically (batch process) (this applies generally to all variants of the process according to the invention). The same applies to the removal of the gasification residue (which consists essentially of ash with residual carbon). The gas streams and vapors generated in the pyrolysis and gasification steps are discharged in a bundled manner (e.g.,(deducted) and fed to the downstream catalytic reformer, which can be operated at temperatures of 700 to 1100 °C. There, the increased surface area of ​​the catalyst (e.g., activated carbon) and the elevated temperatures crack long-chain hydrocarbons into permanent gases, and the dust content in the gas is filtered out. The gas residence time in this process step is typically 0.1 to 20 seconds. In the transition zone between the pyrolysis step and the gasification step, which has not yet been described, pre-reforming takes place—at least when the reactor tube is filled with pyrolyzed solids. This reduces the load on the reformer and, in particular, the service life of the catalyst in the reformer. Fraunhofer reference: UMSICHT-ATZ - 2018P61706WO 22.09.2025.

[0098] TI

[0099] According to a second variant, shown schematically in Figure 2, the plant according to the application has exclusively essentially vertically arranged reaction zones 1, 2, 3, 4. The starting material is fed into the plant from above via a feed device 14. The movement of the starting material to be pyrolyzed in the pyrolysis zone 1 is here essentially by gravity. Two heating devices 12, 13 are shown laterally to the pyrolysis zone 1 (as in all embodiments, they represent "one or more" first—or also second—heating devices). Here, too, the intermediate zone 2 is designed entirely as a pre-reforming zone 2a and filled with pyrolyzed solid. It is evident that no heating device is arranged in the upper region of the pre-reforming zone 2a.This means that in this case, the pre-reforming takes place primarily in the lower part of the pre-reforming zone 2a, since the temperature is higher there due to heat convection from the gasification zone 3. Of course, a heating device can also be arranged in the area of ​​the pre-reforming zone 2a according to this variant. Alternatively, in this embodiment, it would be conceivable that the area of ​​the intermediate zone 2 is unfilled and the pyrolyzed solid from the pyrolysis zone 1 falls directly into the gasification zone 3, the upper boundary of which also coincides with the gasification limit 35; in the area above the gasification limit 35, at most a minimal amount of ungasified pyrolyzed solid is then present. Here too, the gasification zone 3 contains feed devices 31, 32 for the combustion gases, a lower end 30, and a discharge device 33. The filled...

[0100] The gases generated in intermediate zone 2 / pre-reforming zone 2a, the gasification gases, and any remaining pyrolysis gases are fed to reforming zone 4 via an outlet 25. If intermediate zone 2 is empty, the pyrolysis gases and gasification gases are fed to reforming zone 4 via this outlet 25. The required temperature in reforming zone 4, or reforming reactor 4, is provided by the heating device 41 (here, as in all embodiments, the heating device refers to one or more heating devices). Gases generated in reforming zone 4 are drawn off in the lower section of reforming reactor 4 via an outlet 45. The catalyst feed and discharge points in reforming reactor 4 are not shown. Fraunhofer designation: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0101] 28

[0102] An exemplary procedure that can be carried out with the device according to the second variant can be described as follows:

[0103] First, the feedstock is thermochemically converted in a pyrolysis step in a vertical tube (without internals, or alternatively, if necessary, with an agitator or augers) under anaerobic conditions and at a temperature of approximately 500 °C applied externally via a heating device. The solids remain in the tube for a residence time of, for example, 10 to 15 minutes. In the subsequent step—which can take place in the same vertical reactor tube as the pyrolysis step—a combustion gas is added to the resulting pyrolyzed solid. This causes at least a partial conversion of the pyrolyzed solid to gaseous products and ash, resulting in a hydrogen-rich synthesis gas. The desired stoichiometric ratio of hydrogen to carbon monoxide can be adjusted by varying the amount of water added relative to the oxygen.The hydrogen content can also be varied in the different stages of the reactor by controlling the temperature and the water-gas shift reaction. The gas streams and vapors generated in the pyrolysis and gasification steps are collected and discharged (e.g., by extraction) and fed to the downstream catalytic reformer, which can be operated at temperatures from 700 to 1100 °C. The catalyst used there (e.g., activated carbon) typically has a very high BET surface area. Long-chain hydrocarbons are then cracked into permanent gases on this large surface. The gas residence time in this process step is typically 0.1 to 20 seconds. Pre-reforming takes place in the transition zone between the pyrolysis and gasification steps, which has not yet been described. This reduces the load on the reformer and, in particular, the service life of the catalyst within the reformer.

[0104] According to a third variant, shown schematically in Figure 3, the plant according to the application has only three, and not four, reaction zones, all of which are arranged essentially vertically. This results in an embodiment in which the reactor is completely filled (in the horizontal direction) from top to bottom with the starting materials / pyrolyzed solids / gasified solids. Intermediate zone 2 is identical to reforming zone 4. [FhG mark: UMSICHT-ATZ - 2018P61706WO 22.09.2025]

[0105] 29

[0106] Intermediate zone 2 represents (again) the transition to the higher temperature range, as the heating devices 18 located in the intermediate zone provide a higher temperature than the heating devices 12 located in the pyrolysis zone 1. The lower end of intermediate zone 2 always coincides with the gasification boundary 35 of gasification zone 3. In this variant, the starting materials are fed in via a feed device 14. If necessary, reforming catalysts intended for the reforming zone 4, or their precursors, can also be fed in via this device. Pyrolysis zone 1 has a heating device 12; the movement of the starting material towards intermediate zone 2 is again primarily by gravity. Reforming of the pyrolysis gases then takes place in intermediate zone 2, and these gases are discharged in the lower part of intermediate zone 2 via an outlet 40 (for example, by means of an annular gap exhaust).Along with the pyrolysis gases, the gasification gases are also discharged, having likewise passed a short distance through the lower end of the intermediate zone 2. As in the other variants, the gasification zone has a lower boundary 30, below which the discharge device 33 is located; the gasification gases are supplied via the feed devices 31 and 32, one of which (31) is located in the lower region of the gasification zone 3 and a second (32) is already located in the region of the discharge device 33.

[0107] An exemplary procedure that can be carried out with the device according to the third variant can be described as follows:

[0108] First, the feedstock is thermochemically converted in a pyrolysis step in a vertical tube (without internals, or optionally with an agitator or screws) under anaerobic conditions and at an external temperature of approximately 500 °C applied via a heating device. The solids residence time is, for example, 10 to 15 minutes. In the subsequent step—which can take place in the same vertical reactor tube as the pyrolysis step—integrated catalytic reforming occurs. Following the reforming step, the gasification zone is located—also in the same vertical reaction tube. As with all variants, the gasification zone involves the conversion of the added solids. [FhG mark: UMSICHT-ATZ - 2018P61706WO 22.09.2025]

[0109] 30 °C below the ash melting point. The gas streams generated in the upper part of the reactor (i.e., the pyrolysis zone) and the lower part (gasification zone) are fed to the intermediate reforming zone, which operates at 700 to 1100 °C. The catalyst in the reforming zone is the pyrolyzed solid produced in situ from the pyrolysis (optionally, an additional catalyst, defined as described above for the reforming zone of the other variants, may be added). Here, too, long-chain hydrocarbons are cracked into permanent gases during the reforming step, and the dust content in the gas is filtered out. The gas residence time in this process step is typically 0.1 to 20 seconds. The adjustment of the hydrogen / carbon monoxide ratio of the synthesis gas generated is governed by the procedures described for the variants mentioned above. of sewage sludge as feedstock according to variant 1

[0110] 45 kg of pelletized sewage sludge are fed as feedstock at a feed rate of 1.25 kg / h via a double airlock followed by a rotary valve to the pyrolysis zone of the reactor. The observed test period is therefore 4 hours. The temperature in the pyrolysis zone is 450 °C; the solids residence time is 5 minutes. The pyrolyzed solids formed by the pyrolysis of this ash-rich feedstock fall into the fixed-bed gasifier and are gasified there in a countercurrent process with air (64.3 L / min injected) and steam (80.3 L / min injected) as an oxidizing agent mixture. A temperature of 800 °C is reached. The resulting ash is discharged from the process into an ash container via a screw conveyor. The pyrolysis gas produced during pyrolysis and the gasification gas produced during gasification mix in the transition zone between the pyrolysis zone and the gasification zone (the intermediate zone).The gases flow from the pre-reforming zone into the reforming zone, which is heated externally by heating jackets. In this zone, the gases are passed over a 55-liter fixed bed of activated carbon; the temperature in the reformer is 820 °C, and the gas residence time is approximately 0.5 s. The resulting gases are then fed to the gas purification system, which consists of a cooler and an injection pump. The entire system is shrouded in nitrogen throughout the experiment (addition: 5 L / 7 min). Fraunhofer designation: UMSICHT-ATZ - 2018P61706WO 22.09.2025.

[0111] 31

[0112] Table 1 shows the gas composition of a gas sample analyzed in a gas chromatograph after one hour of operation; Table 2 shows the mass balance calculated after four hours:

[0113] Table 1

[0114] Table 2

[0115] Example 2: Conversion of sewage sludge according to variant 1 with variation of the reforming temperature or gas residence time. As in Example 1, 12 kg / h of pelletized sewage sludge is pyrolyzed over a period of 8 hours, and the resulting substances are then fed to the gasification zone and the reforming zone. The reactor volume of the activated carbon-filled reformer is 0.055 Nm³. 3 ; accordingly, the gas residence time is approximately 1 s.

[0116] By lowering the internal temperature in the reforming zone from an initial 715°C to 575°C, the gas composition is changed, specifically the H2 / CO ratio.

[0117] Ratio. The H2 / CO ratio can therefore be adjusted via the temperature control.

[0118] Figure 4 shows the temporal evolution of reformer temperature and gas composition. In the diagram, the temperature in the reforming zone is plotted against time. Fraunhofer reference: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0119] The graph shows 32 measured temperatures (circles) plotted against the concentrations of CH4 (black triangles), CO (squares), H2 (diamonds), and CO2 (gray triangles) measured using a GENTWO V2.2 multigas analyzer from M&C-Techgroup (CH4, CO, and CO2 measured using an NDIR / NDUV photometer; H2 measured using a thermal conductivity detector). The abscissa represents the time course in hours, the ordinate on the left the gas composition in vol.%, and the ordinate on the right the temperature in °C. It is evident that the concentration of H2 decreases significantly with decreasing temperature, and consequently, the H2 / CO ratio changes. The carbon monoxide content remains essentially unchanged (as does the carbon dioxide content). The measured methane value is influenced by cross-sensitivities with hydrocarbons and is therefore quantitatively inaccurate. Qualitatively, however, it shows that the hydrocarbon content in the product gas increases with decreasing temperature.To determine quantitatively precise values, gas samples were analyzed in a gas chromatograph after one hour (i.e., at 715 °C) and after three hours (i.e., at 575 °C). Table 3 shows the results.

[0120] Table 3

[0121] Figure 5 shows the formation of CO and H2 at different temperatures in the

[0122] Reformer for an embodiment in which the temperature during reforming is controlled by Fraunhofer designation: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0123] 33 is kept at a constant value throughout (otherwise the reaction conditions specified above apply). The proportions of the gases methane (diamonds), CO (squares), CO2 (triangles), and H2 (crosses) in volume percent are plotted vertically against the reformer temperature in °C in the horizontal direction. It is evident that (due to the endothermic reactions for the formation of CO and H2) the higher the temperature in the reformer, the more synthesis gas is produced. The CO and especially the H2 proportion increases continuously at temperatures between 500°C and 850°C, while the CO2 proportion steadily decreases, and the methane proportion also tends to decrease at lower levels.

[0124] Figure 6 shows the influence of even longer gas residence times in the reforming zone on the hydrogen / carbon monoxide ratio at a temperature of 850°C in the reformer for the same system (only the gas fractions of hydrogen, carbon monoxide, and carbon dioxide in the gas mixture obtained after step E) are shown). It can be seen that with longer residence times, the carbon monoxide fraction increases while the hydrogen content remains constant. In the diagram, the volume fraction of the three components mentioned is plotted against the volume flow rate in m³ / h. 3 The graph shows the gas residence time in liters per hour (higher values ​​for the volumetric flow rate correspond to shorter residence times). The gas residence time is calculated using the reaction volume in the reformer, the mass of the activated carbon, the porosity factor e = 0.4 for activated carbon, and the product gas volumetric flow rate including the calculated volume change at 850°C, as well as the sum of the water vapor present in the reformer. From left to right, it is 3.92 s, corresponding to 4.3 m. 3 / h, 3.17 s, 2.63 s, 2.35 s, 2.13 s corresponding to 7.05 m 3 / h). If the gas residence time is extended, the carbon monoxide concentration increases continuously and the carbon dioxide concentration decreases continuously.

[0125] Figure 7 shows the influence of the pre-reforming zone in this system, specifically the ratio of the gases methane, hydrogen, carbon monoxide, and carbon dioxide captured after reforming. The concentrations of hydrogen (crosses), carbon monoxide (squares), carbon dioxide (triangles), and methane (diamonds) are plotted for various pre-reforming zone temperatures in °C. It is evident that pre-reforming at higher temperatures tends to lead to higher concentrations of carbon monoxide and hydrogen. Fraunhofer reference: UMSICHT-ATZ - 2018P61706WO 22.09.2025

[0126] 34

[0127] Example 3: Conversion of wood pellets according to variant 1 with variation of the reforming temperature

[0128] As in Example 2, 12 kg / h of feedstock is pyrolyzed over a period of 8 hours, and the resulting products are then fed to the gasification zone and the reforming zone. However, in Example 3, wood pellets (i.e., a particularly low-ash feedstock with an ash content of approximately 1 wt%) are used as the feedstock. The reactor volume of the reformer, which is filled with activated carbon, is 0.055 Nm³. 3 ; accordingly, the gas residence time is approximately 1 s.

[0129] By increasing the internal temperature in the reforming zone from an initial 590°C to 725°C, the gas composition is changed, specifically the H2 / CO ratio. The H2 / CO ratio can therefore be adjusted via temperature control.

[0130] Figure 8 shows the temporal development of reformer temperature and gas composition. The diagram plots the temperature measured in the reforming zone (circles) against time, as well as the concentrations of CH4 (black triangles), CO (squares), H2 (diamonds), and CO2 (gray triangles) measured using a GENTWO V2.2 multigas analyzer from M&C-Techgroup. The x-axis represents the time course in hours, the y-axis (left) the gas composition in vol.%, and the y-axis (right) the temperature in °C. It is evident that the concentration of H2 increases significantly with rising temperature, and consequently, the H2 / CO ratio changes. The carbon monoxide content remains almost unchanged (as does the carbon dioxide content). It is also apparent that at the same temperature, the hydrogen content decreases and the methane content increases with increasing catalyst service life.It is evident that the decreasing activity of the consumption catalyst can be counteracted by increasing the temperature in the reformer. The measured methane value is quantitatively incorrect here as well. Qualitatively, however, it shows that the hydrocarbon content in the product gas decreases with increasing temperature. To determine quantitatively accurate values, a gas sample was analyzed in a gas chromatograph after one hour (i.e., at 590 °C) and after three hours (i.e., at 725 °C). Table 4 shows the result: Fraunhofer reference: UMSICHT-ATZ - 2018P61706WO 22.09.2025.

[0131] 35

[0132] Table 4

Claims

Fraunhofer symbol: UMSICHT-ATZ - 2018P61706WO 22.09.2025 36 Patent claims 1. A process for producing synthesis gas from a starting material, in particular a starting material that is at least partially biogenic, comprising the following steps A) Pyrolysis of the starting material in a pyrolysis zone (1) essentially in the absence of oxygen at a temperature of 250°C to 700°C, in particular 300°C to 600°C, for example 400°C to 550°C, wherein the residence time of the material to be pyrolyzed in the pyrolysis zone (1) is one second to one hour, yielding pyrolyzed solids as well as pyrolysis gases, B) Feeding the pyrolyzed solids to a gasification zone (3), wherein the pyrolyzed solids are first passed through an intermediate zone (2) before reaching the gasification zone (3), C) Supply of combustion gases containing or consisting of at least water and oxygen to the gasification zone (3), wherein the combustion gases are guided through the gasification zone (3) in the opposite direction to the supply direction of the pyrolyzed solids, wherein gasification of the pyrolyzed solids takes place at a temperature of 600 to 1200 °C, in particular 650 to 1100 °C, for example 700 to 900 °C, and wherein gasification gases and ash are formed. D) Removal of the pyrolysis gases from the pyrolysis zone (1) and / or the intermediate zone (2) located between the pyrolysis zone (1) and the gasification zone (3), and removal of the gasification gases from the gasification zone (3) and / or the intermediate zone (2) located between the pyrolysis zone (1) and the gasification zone (3), and feeding the removed gases to a reforming zone (4), so that a mixture of the pyrolysis gases and the gasification gases takes place at the latest in the reforming zone (4). E) Reforming the gas mixture of gasification gases and pyrolysis gases in the reforming zone (4) by contacting it with a bed of catalyst, wherein the reforming takes place at a temperature of 700 °C to 1100 °C, in particular 800 to 950 °C, for example 850 to 900 °C, and wherein Fraunhofer symbol: UMSICHT-ATZ - 2018P61706WO 22.09.2025 37 Synthesis gas is obtained F) Collecting the synthesis gas obtained.

2. A method according to the preceding claim, wherein the intermediate zone (2) is a pre-reforming zone (2a) and the pyrolysis gases in the pre-reforming zone (2a) are pre-reformed at a temperature which is at least in some areas higher than the temperature of the pyrolysis zone (1), in particular at a temperature of 500 to 900 °C, in particular 550 to 800 °C, for example 600 to 650 °C, whereby pre-reformed pyrolysis gases are formed.

3. Method according to claim 1, wherein in step D) the removal of the pyrolysis gases from the pyrolysis zone (1) and the gasification gases from the gasification zone (3) is carried out in such a way that they are supplied to the intermediate zone (2) located between the pyrolysis zone (1) and the reforming zone (3) from opposite directions, the intermediate zone (2) being formed by the reforming zone (4).

4. Method according to one of the preceding claims, wherein the feed direction of the pyrolyzed solids in step D) has a component pointing in the direction of gravity and in particular is substantially in the direction of gravity.

5. Method according to one of the preceding claims, wherein the intermediate zone (2) is at least partially completely filled with pyrolyzed solids perpendicular to the feed direction of the pyrolyzed solids.

6. Method according to one of the preceding claims, wherein the reforming zone (4) is at least partially completely filled with the catalyst perpendicular to the direction of supply of the gas mixture.

7. A method according to any one of the preceding claims, wherein the catalyst used in the reforming zone (4) is selected from the group Fraunhofer symbol: UMSICHT-ATZ - 2018P61706WO 22.09.2025 38 consisting of activated carbon, activated coal, mineral catalysts, in particular metal oxides, zeolites, aluminosilicates and dolomite, as well as freshly formed pyrolyzed solids and mixtures of the aforementioned substances.

8. Method according to any of the preceding claims, wherein the catalyst used in the reforming zone (4) is added to the starting material.

9. Method according to one of the preceding claims, wherein in step A) a starting material with a dry matter content > 70 wt. % is provided.

10. System for carrying out the method according to one of the preceding claims with - a pyrolysis zone (1) for the thermal treatment of a starting material in the absence of oxygen, with a pressure-tight inlet (14) for supplying the starting material and with a first heating device (12) for providing the temperature required for pyrolysis - a gasification zone (3) with at least one first metering device (31, 32) for the supply of water and oxygen and a discharge device (33) for solid gasification products - an intermediate zone (2) and a reforming zone (4) which may optionally be designed at least as a sub-area of ​​the intermediate zone (2), wherein at least in the reforming zone (4) reforming of at least the pyrolysis gases and the gasification gases takes place and wherein optionally second heating means (41, 42) are provided for supplying the temperature required for reforming - a device (45) for the discharge of the synthesis gas obtained after reforming. 1 1. Plant according to the preceding claim, wherein the gasification zone (3) does not have a heating device, so that the gasification temperature is generated only by the reaction of oxygen and / or water with the pyrolysis products. Fraunhofer symbol: UMSICHT-ATZ - 2018P61706WO 22.09.2025 39 12. System according to any one of the preceding claims, wherein the first metering device (31) is provided for the supply of oxygen and a second metering device (32) is provided for the supply of water.

13. System according to any one of the preceding claims, wherein the intermediate zone (2) is substantially vertically oriented.

14. Plant according to the preceding claim, wherein the reforming zone (4) is also substantially vertically oriented.

15. Plant according to one of the preceding claims, wherein the pyrolysis zone (1) is a means for mixing the material to be pyrolyzed Contains source material.

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