Method and apparatus for producing methanol

Abstract

The invention relates to a method for producing methanol, comprising: performing (S10) a first reaction process at a first temperature (T1), wherein the first reaction process produces a synthesis gas containing carbon dioxide (CO2) using biomass and oxygen; performing (S20) a second reaction process in the form of a reverse water gas shift reaction at a second temperature (T2) using the produced synthesis gas, wherein the second reaction process increases the carbon monoxide (CO) content in the synthesis gas, wherein the second temperature (T2) is greater than 400°C; and performing (S50) a methanol synthesis using the synthesis gas to produce methanol. Furthermore, the invention relates to an apparatus for carrying out the method.

Description

Technical Field

[0001] The present invention relates to a method for producing methanol and an apparatus for producing methanol. Background Technology

[0002] To produce fuel from renewable energy sources, it is known that methanol is first produced by reacting carbon dioxide or carbon monoxide with hydrogen according to the following two reaction equations: (1) CO2+3H2→CH3OH+H2O (2) CO+2H2→CH3OH.

[0003] The carbon dioxide or carbon monoxide required for methanol synthesis is provided, for example, by syngas, which is produced by upstream biomass combustion or gasification, also known as the combustion route or gasification route, respectively.

[0004] Biomass is usually burned in an excess of oxygen, so the carbon contained in biomass is mainly converted into carbon dioxide, as shown in the following reaction equation (3): (3) Biomass + O2 → CO2 + H2O (strong exothermic reaction).

[0005] Therefore, the combustion exhaust gas mainly consists of carbon dioxide and water. Finally, hydrogen is added to the combustion exhaust gas to provide synthesis gas for the alcohol synthesis according to the above reaction equation (1).

[0006] Due to the high carbon dioxide content produced by combustion (see reaction equation (3)), the water content generated in methanol synthesis according to the above reaction equation (1) must be significantly reduced in the downstream distillation section in order to provide methanol with a certain purity for fuel production. The setup and operation of the distillation section is technically complex and costly.

[0007] As an alternative to the combustion route, a gasification route can be chosen. In this case, the upstream of methanol synthesis is the gasification of biomass under oxygen-deficient conditions. According to the following reaction equation (4), gasification provides gasification waste gas, i.e., synthesis gas, consisting of carbon monoxide, carbon dioxide, and hydrogen: (4) Biomass + O2 + H2O → CO + CO2 + H2 (The reaction of the O2 part is exothermic).

[0008] Carbon monoxide and carbon dioxide are converted into methanol in the methanol synthesis according to the above reaction equations (1) and (2), or more precisely, crude methanol in the form of a mixture of methanol and water. Due to the carbon dioxide contained in the gasification waste gas or synthesis gas, crude methanol has a certain water content, which must be reduced by the tedious process of distillation.

[0009] For the gasification route, an advantage can be considered to be that it produces less water compared to the combustion route, which must be separated by distillation. On the other hand, combustion is a much more technologically robust process than gasification. For example, biomass with low or non-uniform quality can be readily converted through combustion, whereas the gasification route requires biomass reactants with relatively high or constant quality.

[0010] In summary, it can be considered that the established practice in the prior art is to either isolate the carbon dioxide formed in the gasification route (which leads to a decrease in the carbon yield of the biomass used) or to convert it in methanol synthesis and cumbersomely separate the water formed according to reaction equation (1) by distillation. Summary of the Invention

[0011] Based on known prior art, the object of the present invention is to provide an improved method for producing methanol, a corresponding apparatus for performing the method, and an apparatus for producing methanol.

[0012] This objective is achieved by a method for producing methanol having the features of claim 1. Advantageous improvements are given by the dependent claims, the description, and the drawings.

[0013] Accordingly, a method for producing methanol is proposed, comprising the following steps: - A first reaction process is carried out at a first temperature, wherein the first reaction process uses biomass and oxygen to produce syngas containing carbon dioxide; - Using the prepared syngas, a second reaction process in the form of a reverse water-gas shift reaction is performed at a second temperature, wherein the second reaction process increases the carbon monoxide content in the syngas, and wherein the second temperature is greater than 400°C; and - Methanol is produced by performing methanol synthesis using syngas.

[0014] In this application, when referring to the second reaction process, it refers to a "reverse water-gas shift (referred to as "RWGS" in this application)" reaction or a corresponding RWGS reactor, and vice versa.

[0015] Since the second temperature is greater than 400℃, the known RWGS reaction equation is... (5) CO2+H2↔CO+H2O The balance can be designed to be particularly favorable in order to increase the carbon monoxide content in the syngas and decrease the carbon dioxide content in the syngas. In the following text, reaction equation (5) is sometimes referred to simply as the "RWGS reaction".

[0016] In the context of this invention, it has been recognized that, due to the significant reduction in the carbon dioxide content in the syngas entering methanol synthesis as a reactant, a distillation section for water separation in the methanol synthesis process can be omitted. In this case, by omitting the distillation section, greater savings in process technology and equipment costs can be achieved compared to setting up an RWGS reactor or RWGS catalyst for performing the RWGS reaction.

[0017] Furthermore, it has been recognized that by performing the RWGS reaction, the unwanted carbon dioxide separation from the syngas can be eliminated. Instead, the carbon dioxide can be converted into carbon monoxide, which is desired for methanol synthesis, by the RWGS reaction, thereby increasing the carbon yield of the biomass used in the first reaction process.

[0018] The main concept behind this invention is to reduce the content of unwanted components in syngas through an endothermic reaction, and at the same time, to perform the endothermic reaction in a convenient manner by utilizing the process heat from adjacent reaction processes.

[0019] Since the second temperature (also referred to as the RWGS temperature in this application) only needs to be greater than 400°C, the process heat of the first reaction or the process heat of methanol synthesis can be conveniently used for the endothermic RWGS reaction, for example. In this way, the advantages mentioned above can be achieved, such as increased carbon yield or elimination of the distillation section, without requiring significant additional energy consumption to carry out the RWGS reaction. In other words, from an overall balance perspective, the benefits of eliminating the distillation section or increasing carbon yield significantly outweigh the costs required to carry out the RWGS reaction.

[0020] Furthermore, in the context of this invention, it has been recognized that, since there is less or even no water present in methanol synthesis compared to the prior art, the distillation stage can be completely omitted, especially when producing gasoline via the so-called "methanol-to-gasoline" route or kerosene via the so-called "methanol-to-kerosene" route, since in these two routes a water content of up to 10% in crude methanol is permissible.

[0021] Furthermore, the aforementioned achievable reduction in carbon dioxide in the syngas allows for the generation of more heat in methanol synthesis, since the enthalpy of reaction (2) CO + 2H₂ → CH₃OH is higher than that of reaction (1) CO₂ + 3H₂ → CH₃OH + H₂O. Therefore, more process heat can be utilized without additional overhead, which can further improve the overall equilibrium.

[0022] Furthermore, in the context of this invention, it has been recognized that the service life, or more precisely the service life of the methanol synthesis catalyst, can be extended because there is less or even no water present in methanol synthesis compared to the prior art.

[0023] According to one embodiment, the first reaction process may include the gasification of biomass with oxygen and water vapor, wherein the synthesized gas contains carbon monoxide and hydrogen. Specifically, the first reaction process may be the gasification of biomass. In other words, the first reaction process may be the thermochemical conversion of biomass into synthesized gas containing carbon dioxide. In particular, the gasification parameter known to those skilled in the art as the excess air number may be greater than zero and less than one. In other words, in this case, the first reaction process is carried out under oxygen-deficient or oxygen-deficient conditions. According to this embodiment, the first reaction process is a gasification without subsequent combustion.

[0024] Since the first reaction process can be the gasification of biomass, the resulting syngas may contain carbon monoxide and hydrogen in addition to carbon dioxide. In other words, the carbon dioxide content of the gasification route is lower than that of the combustion route. This way, less carbon dioxide needs to be converted in the second reaction process, and less hydrogen needs to be supplied.

[0025] According to another embodiment, the first reaction process may include the combustion of biomass with oxygen, wherein the synthesized gas contains water. Specifically, the first reaction process may be the combustion of biomass, i.e., the so-called oxy-combustion or oxy-verbrennung of biomass. In other words, the first reaction process may be a combustion process directly produced by igniting gases released from biomass. Specifically, the excess air number in the first reaction process (i.e., oxy-combustion) may be greater than one. In other words, the first reaction process is carried out under conditions of excess oxygen. According to this embodiment, the first reaction process is combustion, which naturally presupposes the release of combustible gases from biomass.

[0026] Since the first reaction process can be the combustion of biomass, it can convert biomass reactants of varying qualities or inconsistent homogeneity into syngas. This allows for simple and robust process management of the first reaction process.

[0027] According to another embodiment, the first reaction process can be carried out in a gasification reactor as gasification, and additionally in a combustion reactor as combustion, wherein the syngas prepared in gasification and the syngas prepared in combustion are combined before methanol synthesis. In other words, gasification, combustion, and methanol synthesis can be carried out in a Y-shaped configuration. In particular, the second reaction process can be carried out after the aforementioned combination, i.e., downstream of the node of the Y-shaped configuration. In this way, the first reaction process can be operated simultaneously in two different embodiments, requiring only one RWGS reactor. Thus, a wider variety of biomass reactants can be processed without the need for an additional RWGS reactor.

[0028] According to one improved scheme, the second temperature is at most 300 Kelvin lower than the first temperature. For example, the first temperature in the form of a combustion temperature for biomass combustion could be 1000°C, while the second temperature in the form of an RWGS temperature is at least 700°C. Furthermore, for example, the first temperature in the form of a gasification temperature could be 500°C, while the second temperature in the form of an RWGS temperature is maintained at 400°C. Through the temperature difference limitation mentioned above, the process heat of the exothermic first reaction process can be used particularly effectively to carry out the RWGS reaction.

[0029] According to one improved scheme, the first temperature can be between 700-1100°C, and the second temperature can be between 380-1100°C. By using the relatively high first temperature in the 700-1100°C range, the high quality of the syngas to be prepared, i.e., a high proportion of the desired short-chain gaseous carbon compounds (particularly, carbon dioxide in the case of combustion, or carbon monoxide and carbon dioxide in the case of gasification), can be achieved. Furthermore, the relatively high first temperature of the exothermic first reaction provides a high potential for available process heat.

[0030] In this application, it has been recognized that if the exhaust gas, more precisely the syngas, produced by the first reaction process has high quality, i.e., low content of undesirable byproducts (such as tar or wood condensate), a purification stage for its purification can be omitted. Therefore, when the process management of the first reaction process results in high exhaust gas quality, it is particularly convenient to integrate the RWGS catalyst into the exhaust gas pipeline of the first reaction process.

[0031] Furthermore, as mentioned above, the RWGS reaction can be carried out over a relatively wide temperature range, spanning 720 Kelvin within the range of 380-1100 °C. In this way, the RWGS reaction can be carried out, for example, at a moderate temperature of about 450 °C (i.e., significantly lower than the first temperature), and thus spatially decoupled from the first reaction. Due to the high temperature difference, even though spatially decoupled, the exothermic first reaction process can still provide process heat to carry out the RWGS reaction.

[0032] In the context of this application, temperatures below 350°C are referred to as low, temperatures above 750°C are referred to as high, and temperatures in between are referred to as medium.

[0033] In the context of this invention, it has been recognized that, since the RWGS reaction is spatially decoupled from the first reaction process, a syngas purification system can be connected between the first and second reaction processes. In this way, undesirable byproducts (such as tar or wood condensate) can still be separated from the syngas before the second reaction process, thus the RWGS catalyst used in the second reaction process is contaminated, clogged, or worn out more slowly.

[0034] It has been recognized that catalysts, especially those designed for relatively low RWGS temperatures (i.e., approximately 400-500°C), should be protected against the effects of undesirable byproducts or residues in the syngas. Therefore, the proposed improvement enables the inclusion of a purification section to achieve a long service life for the RWGS catalyst, while simultaneously providing process heat for the first reaction stage of the RWGS reaction.

[0035] According to one improvement, the second temperature can be at least 80% of the first temperature. For example, the second temperature can be 80%, 90%, 110%, or 120% of the first temperature, or any value in between. In other words, the first and second temperatures can differ from each other by up to 20%. When the second temperature is 80-100% of the first temperature, the RWGS reaction can be conveniently spatially coupled to the first reaction process, for example, by integrating the RWGS catalyst into an exhaust gas line for discharging the synthesized syngas from the first reaction process. In this way, both the first and second reaction processes can be performed at very high temperatures (e.g., about 1000°C). This allows for high-quality syngas, potentially eliminating the need for upstream purification of the syngas from the RWGS catalyst. Furthermore, those skilled in the art can design particularly simple and durable RWGS catalysts, designed for efficient operation at high temperatures, due to the relatively high RWGS temperatures.

[0036] According to another embodiment, the execution of the first reaction process may include discharging the prepared syngas through an exhaust gas pipeline, wherein the execution of the second reaction process is integrated into the discharge of the prepared syngas. Specifically, in this case, an RWGS catalyst may be arranged in the exhaust gas pipeline of the first reaction process. In this way, the temperature difference between the first and second reaction processes can be kept very small.

[0037] According to another embodiment, the method may include the step of supplying hydrogen, in particular, in excess form, to the reactant side of the second reaction process. In other words, additional hydrogen is provided as a reactant in the RWGS reaction, especially more than the hydrogen that can typically be converted from the prepared syngas in the RWGS reaction. In this way, the RWGS reaction equilibrium is influenced favorably for the desired products. Specifically, carbon dioxide and hydrogen can thus be converted to carbon monoxide and water in a very high proportion or even completely in the RWGS reaction. For example, the residual carbon dioxide content in the syngas can therefore be reduced to below 1%. This makes it more likely that a distillation stage can be omitted after methanol synthesis, since at most 1% carbon dioxide results in a correspondingly low water content in the crude methanol. In this application, it has been recognized that when the water content in the crude methanol is 1-10%, a distillation stage can be omitted when the crude methanol is used to produce a specific so-called biofuel with a corresponding methanol content of at least 90%.

[0038] According to another embodiment, the method may include the following steps: - The prepared syngas is guided through a regenerative heat exchanger; - Cool the syngas to the purification temperature; - Purify the cooled synthesis gas; - The purified syngas is heated to a second temperature via a regenerative heat exchanger; and - The heated syngas is supplied to the second reaction process.

[0039] Because of the use of a regenerative heat exchanger, syngas can be purified even upstream of the RWGS catalyst, while the process heat from the first reaction can be used to execute the RWGS reaction. For example, the first reaction can be carried out at a high temperature of 800-1000°C, and purification can be carried out at a purification temperature in the range of 30-350°C. Due to the high first temperature, the purified syngas can be heated to the RWGS temperature, for example, 400°C, 600°C, or 750°C, depending on the investment cost for designing the regenerative heat exchanger.

[0040] Additionally or alternatively, the method may include the steps of: extracting process heat from a first reaction process; and supplying the extracted process heat to a second reaction process. These steps enable the utilization of the process heat of the first reaction process when the RWGS reaction is spatially decoupled from the first reaction process.

[0041] According to another embodiment, the method may include the following steps: - Cool the synthesis gas after the second reaction process; - Compressing cooled synthesis gas; - Optionally: condense water from the cooled syngas and separate the condensed water from the cooled syngas.

[0042] Methanol synthesis can be carried out, for example, in known low-pressure processes, i.e., at pressures of 50 to 100 bar and temperatures of 200 to 300°C. Both the first and second reaction processes can be conducted at relatively low pressures of 1-15 bar. Since the synthesis gas is cooled to, for example, 40°C, the cooled synthesis gas can be economically compressed as needed, for example, to a synthesis pressure of 80 bar.

[0043] In the context of this invention, it has been recognized that water that may be present in the syngas during the cooling process, especially water produced by the combustion of biomass, can be condensed and separated particularly easily. By separating water before compressing the syngas, the volumetric flow rate of the gas to be compressed is significantly reduced. Therefore, the energy consumption required for compression is reduced, and the equipment overhead for providing the compressor on demand is decreased.

[0044] Furthermore, the lifespan of the synthesis catalyst required for methanol synthesis is increased due to the reduction or elimination of water in the process. This is achieved through the water separation mentioned above and the conversion of carbon dioxide to carbon monoxide via the proposed RWGS reaction.

[0045] According to another embodiment, the methanol synthesis includes a synthesis loop for preparing crude methanol, wherein the prepared crude methanol comprises 90.0% to 99.5% methanol and at most 10.0% water. Specifically, the methanol synthesis is performed without methanol distillation for separating water from the crude methanol.

[0046] In this application, a synthesis loop refers to the process or equipment section in a methanol synthesis process or methanol synthesis equipment where reactants hydrogen and carbon monoxide and / or carbon dioxide react to form the product methanol, more specifically crude methanol. Traditionally, the water formed is separated from the crude methanol in a subsequent methanol distillation to obtain pure methanol.

[0047] The objective stated above is further achieved by means of a device having the features of claim 13. Advantageous improvements to the method are given in the description and drawings of this application. Accordingly, an apparatus for performing the method described above is proposed.

[0048] The technical effects and advantages described above regarding the proposed method also apply to the proposed device.

[0049] The objective stated above is further achieved by means of a device having the features of claim 14. Advantageous improvements to the method are given in the description and drawings of this application.

[0050] Accordingly, an apparatus for producing methanol is proposed. The apparatus includes a first reactor for preparing syngas containing carbon dioxide, and an arrangement for the gasification and / or combustion of biomass, wherein the first reactor has an exhaust gas duct for discharging the prepared syngas; and a second reactor, in the form of a reverse water-gas shift reactor, wherein the second reactor, particularly its catalyst, is arranged within the exhaust gas duct and adjacent to the first reactor.

[0051] Because the RWGS reactor (especially the RWGS catalyst) is located within the exhaust gas pipeline and adjacent to the first reactor, the temperature gradient between the gasification or combustion (i.e., the first and second reaction processes described above) and the RWGS reactor can be significantly reduced. Therefore, the process heat from the exothermic first reaction process can be conveniently utilized to perform an endothermic RWGS reaction.

[0052] The objective stated above is further achieved by means of a device having the features of claim 15. Advantageous improvements to the method are given in the description and drawings of this application.

[0053] Accordingly, an apparatus for producing methanol is proposed. The apparatus includes a first reactor for producing syngas containing carbon dioxide, and an installation for the gasification and / or combustion of biomass, wherein the first reactor has a waste gas pipeline for discharging the produced carbon dioxide; a second reactor, which is in the form of a reverse water-gas shift reactor; a regenerative heat exchanger; and a purification tower. The purification tower is arranged between the first and second reactors and is fluidly connected to both reactors. The regenerative heat exchanger is configured to heat transfer between the outlet pipeline of the first reactor and the inlet pipeline of the second reactor.

[0054] The purification tower arranged between the first and second reactors can separate unwanted byproducts (such as tar or wood condensate) from the syngas produced in the first reactor, thereby significantly improving the service life of the second reactor (especially its RWGS catalyst). Due to the proposed arrangement of a regenerative heat exchanger, the process heat from the exothermic first reaction can be used to heat the purified syngas, thus allowing the endothermic second reaction to proceed without additional energy consumption, even if the first and second reactors are spatially decoupled due to the intermediate purification tower. Attached Figure Description

[0055] Other preferred embodiments of the present invention will be explained in detail with reference to the following drawings. Indicatively: Figure 1a A flowchart of a method for producing methanol according to a first embodiment is shown; Figure 1b ,1c Each is shown as an embodiment of a device for performing the method; Figure 2a A flowchart of a method for producing methanol according to yet another embodiment is shown; Figure 2b An embodiment of an apparatus for producing methanol is shown; Figure 3a A flowchart of a method for producing methanol according to yet another embodiment is shown; Figure 3b Another embodiment of an apparatus for producing methanol is shown; and Figure 4 Another embodiment of a device for performing the method is shown. Detailed Implementation

[0056] Preferred embodiments are described below with reference to the accompanying drawings. Here, in different drawings, the same, similar, or equivalent elements are labeled with the same reference numerals, and repeated descriptions of these elements are omitted to avoid redundancy.

[0057] Figure 1a A flowchart illustrating a method for producing methanol according to a first embodiment is shown schematically. Figure 1b and Figure 1c A corresponding embodiment of a device for performing this method is shown. For example... Figure 1a As shown, the first reaction process S10 is first carried out at a first temperature T1. The first reaction process uses biomass and oxygen to produce a carbon dioxide-containing waste gas, also referred to herein as the produced syngas. The first reaction process can be, for example, industrial biomass gasification or biomass combustion in the form of so-called aerobic combustion. Alternatively, the first reaction process can be any other form of exothermic biomass utilization to produce carbon dioxide-containing syngas.

[0058] Subsequently, using the prepared syngas, a second reaction process in the form of an S20 reverse water-gas shift reaction is carried out at a second temperature T2. Those skilled in the art can select a suitable RWGS catalyst such that the RWGS reaction increases the carbon monoxide content in the syngas according to the following reaction equation (5): (5) CO2 + H2 ↔ CO + H2O (strong endothermic).

[0059] The known RWGS catalysts achieve this effect at a second temperature T2 (i.e., the RWGS temperature) exceeding 400°C.

[0060] In step S21, excess hydrogen is supplied to the RWGS reaction, wherein the amount of excess is measured depending on the carbon dioxide content of the syngas prepared in the first reaction, taking into account the above-described RWGS reaction equation.

[0061] After step S20, in step S30, the RWGS-modified syngas (i.e., syngas with higher carbon monoxide content and lower carbon dioxide content compared to syngas directly from the first reaction process) is cooled.

[0062] Cooling step S30 includes targeted condensation of water S32, in which the water is separated from the cooled syngas in a further step S35. After cooling S30, the cooled syngas is compressed S40, and then methanol synthesis S50 is performed using the syngas to produce methanol.

[0063] Steps S10, S20, and S30 can be carried out at a pressure between 1 and 15 bar, wherein the pressure can be any value between these values, independent of the corresponding reaction temperature. By cooling S30, the synthesis gas is cooled to a temperature between 20°C and 100°C, for example, 30°C, 40°C, or 50°C.

[0064] It has been recognized that the pressure in the second reaction process can be variably adjusted within the range of 1-15 bar without negatively impacting the second reaction process, i.e., without negatively impacting the expected reduction in carbon dioxide content in the syngas. Therefore, the pressure in the second reaction process can depend accordingly on the pressure of the first reaction process, and in particular, can have substantially the same value. In this way, the RWGS catalyst can be conveniently integrated into the exhaust gas line of the first reaction process.

[0065] By compression S40, the cooled synthesis gas is placed at the pressure required for methanol synthesis, for example, between 50 and 100 bar, so that a known low-pressure process for methanol synthesis can be performed in step S50.

[0066] Figure 1b A device 1 is shown for performing the method according to the gasification route. Figure 1c A corresponding device 1 for the combustion path is shown. For example... Figure 1b As shown, the device 1 includes a first reactor 10 in the form of a gasification reactor 10, which has an exhaust gas pipeline 11 in which an RWGS catalyst 20 is arranged or integrated. Therefore, the RWGS catalyst 20 integrated into the exhaust gas pipeline performs the function of the second reactor 20 (i.e., the RWGS reactor 20).

[0067] Downstream, connected in sequence to the exhaust gas pipeline 11 are: a cooling section 30 for cooling S30, a compressor 40 for compressing S40, and a synthesis loop 50 for performing methanol synthesis of S50.

[0068] The device 1 also includes a supply line 21 for supplying hydrogen to S21, wherein, according to Figure 1bIn the illustrated embodiment, the supply line 21 can be arranged upstream or downstream of the RWGS catalyst 20 in the flow direction. In the current figures, the flow direction of device 1 is substantially from left to right and is indicated by the arrow direction of the syngas, which is simply referred to as SynGas in the figures.

[0069] exist Figure 1c The device 1 shown is basically the same as in Figure 1b Corresponding to the device 1 shown, the difference is that the first reactor 10 is in the form of a combustion reactor, used to perform S10 aerobic combustion of biomass under conditions of excess oxygen.

[0070] Syngas produced by combustion is discharged from the first reactor 10 via exhaust pipe 11, in which an RWGS catalyst is arranged. In this embodiment, S21 hydrogen is supplied upstream of the RWGS catalyst 20, i.e., between the first reactor 10 and the RWGS catalyst 20. Furthermore, S21 hydrogen can be supplied again downstream of the RWGS catalyst 20 (not in...). Figure 1c (As shown in the image).

[0071] Figure 2a A flowchart of a method for producing methanol according to yet another embodiment is schematically shown. In this embodiment, syngas prepared by a first reaction process S10 and modified by a second reaction process S20 is purified before cooling S30. For this purpose, the syngas, which has a second temperature T2 (e.g., about 700°C) greater than 400°C in the second reaction process, is first cooled to a purification temperature T3 in the range of 250-350°C in a cooling step S13. The purification temperature T3 is then selected such that the components to be separated in the purification step, such as tar or wood condensate, are mostly separated or condensed from the syngas.

[0072] The syngas, cooled to purification temperature T3, is then purified in S14, for example by separating components that have been separated or condensed from the syngas. This is followed by cooling in S30, compression in S40, and methanol synthesis in S50, as described in the previous examples.

[0073] Figure 2b The illustration shows the setup for execution. Figure 2a The apparatus 1 of the method shown. The first reactor 10 may be a gasification reactor and / or a combustion reactor. When the first reactor 10 is a simple combustion reactor, hydrogen is supplied to the exhaust gas line 11 upstream of the RWGS catalyst 20 via the supply line 21.

[0074] according to Figure 1b , Figure 1c and Figure 2bIn this embodiment, the RWGS catalyst 20 is correspondingly integrated into the exhaust gas duct 11 of the first reactor 10. Therefore, similar pressure and temperature conditions exist in the RWGS catalyst 20 as in the first reactor 10. For example, the first reactor can operate at any pressure between 1 and 15 bar and can have a first temperature T1 greater than 400°C. In the example shown, the first temperature T1 is greater than 750°C. By arranging the RWGS catalyst 20 adjacent to the first reactor 10 within the exhaust gas duct 11, a second temperature T2 can be achieved that is only slightly lower than the first temperature T1, for example, by at most 50 Kelvin. Figure 1b , Figure 1c and Figure 2b As shown in the diagram. In this way, no additional heat energy is required to perform the second reaction process S20.

[0075] In all embodiments, a particulate filter (not shown) may optionally be provided in the first reactor 10 and / or in the exhaust gas duct 11 upstream of the second reactor 20 to reduce the particulate load on the RWGS catalyst 20 and extend its service life.

[0076] Figure 3a A flowchart of a method for producing methanol according to yet another embodiment is shown schematically. Figure 3b The illustration shows the setup for execution. Figure 3a Device 1 of the method shown. (e.g.) Figure 3a , Figure 3b As shown, the syngas prepared in step S10 of the first reaction process is first discharged from the first reactor 10 through the waste gas pipeline 11, S11. Subsequently, the still-hot syngas is guided through the regenerative heat exchanger 16, S12. Then, the syngas is supplied to purification towers 12 and 13, where the syngas is first cooled to the purification temperature T3, S13, and purified, S14. Through the purification section 14, undesirable byproducts, such as tar and wood condensate, are separated from the syngas.

[0077] Subsequently, the purified syngas is supplied to the second reactor 20 through inlet pipe 17 to perform the second reaction process S20, S17, wherein inlet pipe 17 passes through a regenerative heat exchanger 16, thereby heat-transferringly coupling the outlet pipe 11 of the first reactor 10 to the inlet pipe 17 of the second reactor 20. Through this coupling of the regenerative heat exchanger 16, the purified syngas is heated from a low purification temperature T3 to a medium or high second temperature T2 in S16.

[0078] Furthermore, the method may additionally include the steps of: extracting process heat from the first reaction process S22 and supplying the extracted process heat to the second reaction process S24. Accordingly, the apparatus 1 may include a heat transfer device 22 configured to perform steps S22 and S24.

[0079] The arrangement of the heat transfer device 22 allows the size design of the regenerative heat exchanger 16 to make it particularly inexpensive or to operate at high flow rates, such that the purified syngas may not have reached the desired second temperature T2 when it is supplied to the second reactor 20 via S17.

[0080] exist Figure 3b The temperature of the syngas is illustrated as follows: gasification S10 or combustion S10 is carried out, for example, at about 920°C. The syngas thus prepared may therefore have a temperature of 900°C in step S12, wherein the syngas may be cooled by several times fifty Kelvin, for example, to 700°C, in heat exchanger 16 by releasing heat to the purified syngas that cross-flows in heat exchanger 16.

[0081] In the subsequent step S13, the syngas is then cooled to a purification temperature T3, for example, 300°C. Through the heat release described above, the purified syngas can then be heated several times the amount of fifty Kelvin in heat exchanger 16, for example, to 600°C. If an RWGS catalyst 20 is provided in the second reactor 20 (for which the RWGS reaction is particularly advantageously carried out at high temperatures, for example above 700°C or 750°C), the missing heat can be conveniently provided from the exothermic and sufficiently hot first reaction process via heat transfer device 22.

[0082] Through Figure 3a , 3b The embodiment shown in the diagram allows for the purification of the syngas via a purification tower 13+14 upstream of the RWGS catalyst 20, thereby further extending the service life of the RWGS catalyst 20. Simultaneously, the heat loss required for purification can be compensated for by the heat exchanger 16. In this way, purification can be performed without requiring additional external energy input to reheat the purified syngas.

[0083] Figure 4 Another embodiment of the apparatus for performing the method is schematically shown, wherein apparatus 1 includes two first reactors 10, the synthesis gas streams produced therefrom being combined in a Y-shaped pattern before methanol synthesis 50, particularly before cooling section 30. Figure 4In the example shown, an RWGS catalyst is integrated into each exhaust gas line 11 of the two first reactors 10. In this way, the gasification reactor 10 and its associated RWGS catalyst 20 can operate independently of the combustion reactor 10 and its associated RWGS catalyst 20 in terms of reaction conditions, including pressure and temperature. This allows for a high degree of freedom in process management, while downstream sections, namely the purification towers 13+14 and cooling section 30, compressor 40, and synthesis loop 50, can be shared between the two first reactors 10.

[0084] Alternatively, even in essentially as Figure 4 In the case shown with two first reactors 10 arranged in a Y-shape, each purification tower 13+14 and each heat exchanger 16 can also be connected upstream of the single RWGS reactor 20, as illustrated in principle in Figure 3. In this way, the advantage of extended service life of the RWGS catalyst 20 can be combined with the advantage of arranging two first reactors in a Y-shape, meaning that without the need for a second RWGS reactor, a wider variety of biomass reactants can be processed as needed via gasification or combustion.

[0085] Where applicable, all the various features shown in the embodiments may be combined and / or interchanged with each other without departing from the scope of the invention. For example, in Figure 1b , Figure 1c The device shown can operate at the temperatures mentioned in other embodiments, for example, according to Figure 3b The temperature is the same, and vice versa. Furthermore, a regenerative heat exchanger 16 can be considered in all embodiments, especially when the RWGS catalyst 20 is not arranged adjacent to the first reactor 10.

Claims

1. A method for producing methanol, comprising the following steps: - A first reaction process (S10) is carried out at a first temperature (T1), wherein the first reaction process uses biomass and oxygen (O2) to produce syngas containing carbon dioxide (CO2); - Using the prepared syngas, a second reaction process in the form of a reverse water-gas shift reaction (S20) is performed at a second temperature (T2), wherein the second reaction process increases the carbon monoxide content in the syngas, and wherein the second temperature (T2) is greater than 400°C; and - Using the syngas, perform (S50) methanol synthesis to prepare methanol.

2. The method according to claim 1, wherein, The first reaction process includes the gasification of the biomass with oxygen (O2) and water vapor (H2O), wherein the synthesized gas contains carbon monoxide (CO) and hydrogen (H2).

3. The method according to claim 1 or 2, wherein, The first reaction process includes the combustion of the biomass with the oxygen (O2), and wherein the synthesized gas contains water (H2O).

4. The method according to any one of the preceding claims, wherein, The second temperature (T2) is up to 300K lower than the first temperature (T1).

5. The method according to any one of the preceding claims, wherein, The first temperature (T1) is between 700-1100°C, and the second temperature (T2) is between 380-1100°C.

6. The method according to any one of the preceding claims, wherein, The second temperature (T2) is at least 80% of the first temperature (T1).

7. The method according to any one of the preceding claims, wherein, The execution of the first reaction process (S10) includes the sub-step of discharging (S11) the prepared syngas through the waste gas pipeline (11). The execution of the second reaction process (S20) is integrated into the discharge of the prepared syngas (S11), and in particular, a reverse water-gas shift catalyst (20) is arranged in the exhaust gas pipeline (11) of the first reaction process.

8. The method according to any one of the preceding claims, comprising: - In particular, hydrogen (H2) is supplied in excess on the reactant side of the second reaction process (S21).

9. The method according to any one of the preceding claims, comprising: - The synthesis gas prepared by (S12) is guided through a regenerative heat exchanger (16). - Cool the syngas (S13) to the purification temperature (T3); - Purify (S14) the cooled synthesis gas; - The purified synthesis gas is heated (S16) to the second temperature (T2) via the regenerative heat exchanger (16); and - Heated synthesis gas is supplied (S17) to the second reaction process.

10. The method according to any one of the preceding claims, comprising: - Extract process heat from the first reaction process (S22); as well as - The heat supply for the extraction process (S24) is supplied to the second reaction process.

11. The method according to any one of the preceding claims, comprising the following steps: - The synthesis gas is cooled (S30) after the second reaction process; - Compressed (S40) cooled synthesis gas; - Optionally: condense water (H2O) from the cooled syngas (S32) and separate the condensed water from the cooled syngas (S35).

12. The method according to any one of the preceding claims, wherein, The execution of the methanol synthesis (S50) includes a synthesis loop for preparing crude methanol, wherein the prepared crude methanol contains 90.0% to 99.5% methanol and at most 10.0% water, and in particular, the methanol synthesis (S50) is performed without methanol distillation for separating water (H2O) from the crude methanol.

13. An apparatus (1) configured to perform the method according to any one of the preceding claims.

14. An apparatus (1) for producing methanol, comprising: - A first reactor (10) for preparing syngas containing carbon dioxide (CO2), and for the gasification and / or combustion of biomass, wherein the first reactor has an exhaust gas pipeline (11) for discharging the prepared syngas; and - Second reactor (20), the second reactor is in the form of a reverse water-gas shift reactor (20). The second reactor (20), particularly the catalyst (20) of the second reactor, is arranged in the exhaust gas pipeline (11) and adjacent to the first reactor (10).

15. An apparatus (1) for producing methanol, comprising: - A first reactor (10) is used to prepare syngas containing carbon dioxide (CO2) and to provide for the gasification and / or combustion of biomass, wherein the first reactor (10) has an exhaust gas pipeline (11) for discharging the prepared carbon dioxide (CO2). - Second reactor (20), the second reactor is in the form of a reverse water-gas shift reactor (20); - Regenerative heat exchanger (16); and - Purification towers (13, 14), wherein the purification towers (13, 14) are arranged between the first reactor (10) and the second reactor (20) and are fluidly connected to the first reactor and the second reactor, and - Wherein, the regenerative heat exchanger (16) is provided for heat transfer coupling of the outlet pipe (11) of the first reactor and the inlet pipe (17) of the second reactor (20).

Images