Method and system for coupling biomass gasification and fermentation to methanol production

Abstract

The present application relates to a method and system for coupling biomass gasification and fermentation to produce methanol. The method comprises the following steps: anaerobic fermentation of a first biomass to produce biogas residue and methane; carbonization of the biogas residue to produce biochar; recycling of the biochar to the anaerobic fermentation; reforming of the methane with water to produce a first crude synthesis gas; gasification of a second biomass to produce a second crude synthesis gas; mixing of the first crude synthesis gas and the second crude synthesis gas, and hydrogenation of the resulting mixed gas to produce methanol. The method can effectively improve the carbon efficiency of the biomass raw material and reduce the production cost.

Description

Technical Field

[0001] This application relates to the field of green chemical technology, and in particular to methods and systems for coupling biomass gasification and fermentation to produce methanol. Background Technology

[0002] Methanol is a crucial platform compound for modern industrial and energy transition, possessing the dual attributes of a basic chemical feedstock and a clean energy carrier. As an important basic chemical product, methanol is a key raw material in processes such as formaldehyde, acetic acid, and methanol-to-olefins (MTO). Replacing fossil-based methanol with green methanol can effectively reduce the carbon emission intensity of the chemical industry chain. In the energy sector, methanol has a high volumetric energy density and is easy to store and transport, making it suitable for use as a vehicle / marine fuel. Green methanol, in particular, has significantly lower carbon emissions over its entire life cycle compared to fossil fuels such as gasoline and diesel, making it a vital liquid clean fuel for supporting the achievement of carbon neutrality goals.

[0003] Biomass is widely available and abundant, making the production of green methanol from biomass a highly sought-after method. Currently, green methanol production from biomass includes biomass gasification and biomass fermentation. However, both traditional biomass gasification and fermentation methods suffer from a core problem of carbon-hydrogen imbalance, requiring the addition of other substances to adjust the carbon-hydrogen ratio, leading to carbon resource waste or soaring production costs.

[0004] Therefore, it is necessary to improve traditional technologies. Summary of the Invention

[0005] Based on this, this application provides a method and system for producing methanol by coupling biomass gasification and fermentation, which has high raw material carbon efficiency and low production cost.

[0006] The technical solution to the above-mentioned technical problems in this application is as follows.

[0007] The first aspect of this application provides a method for producing methanol by coupling biomass gasification and fermentation, comprising the following steps:

[0008] Anaerobic fermentation of the first biomass produces biogas residue and methane;

[0009] The biochar is prepared by carbonizing the biogas residue.

[0010] The biochar is reused in the anaerobic fermentation.

[0011] The methane was reformed with water to produce the first crude syngas;

[0012] The second biomass is subjected to a gasification reaction to produce a second crude syngas;

[0013] The first crude synthesis gas and the second crude synthesis gas are mixed, and then the resulting mixture is subjected to a hydrogenation reaction to prepare methanol.

[0014] In some embodiments, the method for coupling biomass gasification and fermentation to produce methanol satisfies at least one of the following characteristics:

[0015] (1) The conditions for the anaerobic fermentation include: a temperature of 35℃~42℃ and a pH value of 6.5~7.6;

[0016] (2) The carbonization temperature is 350℃~700℃.

[0017] In some embodiments, in the method of coupling biomass gasification and fermentation to produce methanol, the first biomass includes at least one of starch and animal manure.

[0018] In some embodiments, in the method of coupling biomass gasification and fermentation to produce methanol, the biochar is recycled into the anaerobic fermentation, including:

[0019] Microorganisms were domesticated by attaching and forming a membrane on the biochar to obtain a biochar-microbial membrane composite.

[0020] The biochar-microbial membrane complex is reused in the anaerobic fermentation.

[0021] Optionally, the microorganisms include methanogenic archaea.

[0022] In some embodiments, in the method of coupling biomass gasification and fermentation to produce methanol, the second biomass includes at least one of starch, animal manure, wheat straw, corn stalks, and wood.

[0023] In some embodiments, in the method of coupling biomass gasification and fermentation to produce methanol, both the first crude syngas and the second crude syngas include CO and H2, and the volume ratio of CO to H2 in the mixed gas is 1:2 to 2.2.

[0024] In some embodiments, in the method of coupling biomass gasification and fermentation to produce methanol, the reforming reaction is carried out at a temperature of 700°C to 900°C and a pressure of 1 MPa to 3 MPa.

[0025] In some embodiments, in the method of coupling biomass gasification and fermentation to produce methanol, the temperature of the gasification reaction is 900°C to 1200°C and the pressure is 0.1 MPa to 3 MPa.

[0026] In some embodiments, the method of coupling biomass gasification and fermentation to produce methanol further includes, before the hydrogenation reaction: removing H2S and CO2 from the mixed gas, and then subjecting the purified syngas to the hydrogenation reaction.

[0027] A second aspect of this application provides a coupled biomass gasification and fermentation methanol production system, comprising a biomass anaerobic fermentation unit, a methane steam reforming reactor, a first syngas storage tank, a biogas residue carbonization unit, a biochar-microorganism composite unit, a biomass gasification unit, a second syngas storage tank, a gas detection and flow control device, a gas purification device, a syngas-to-methanol reaction unit, and a methanol distillation unit. The output end of the biomass anaerobic fermentation unit is sequentially connected to the methane steam reforming reactor, the first syngas storage tank, and the gas detection and flow control device. The biogas residue output end of the device is sequentially connected to the biogas residue carbonization device and the biochar-microorganism composite device. The biochar-microorganism membrane composite output end of the biochar-microorganism composite device returns to the biomass anaerobic fermentation device. The output end of the biomass gasification device is sequentially connected to the second syngas storage tank and the gas detection and flow control device. The output end of the gas detection and flow control device is connected to the gas purification device. The output end of the gas purification device is connected to the syngas-to-methanol reaction device. The output end of the syngas-to-methanol reaction device is connected to the methanol distillation device.

[0028] The method for producing methanol by coupling biomass gasification and fermentation involves carbonizing the biochar obtained from the anaerobic fermentation of the first biomass. The resulting biochar has high porosity and numerous reaction sites. Reusing this biochar in anaerobic fermentation effectively promotes electron transfer in the microbial reaction, improving the production efficiency and yield of methane. Methane and water are reformed to produce a first crude syngas, and the second biomass is gasified to produce a second crude syngas. Both crude and second syngas contain H2 and CO. Compared to the ideal C:H ratio of 1:4 required for methanol synthesis, the first crude syngas contains excess H2, and the second crude syngas contains excess CO. The first and second crude syngas are mixed and hydrogenated to produce methanol. This process results in low CO2 emissions, effectively improving the carbon efficiency of the biomass feedstock. The biochar is derived from biomass, which is widely available and has low production costs. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application and to more completely understand this application and its beneficial effects, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of a process for coupling biomass gasification and fermentation to produce methanol, provided as one embodiment.

[0031] Figure label:

[0032] 1: Biomass anaerobic fermentation unit; 2: Methane steam reforming unit; 3: First syngas storage tank; 4: Sludge carbonization unit; 5: Biochar-microorganism composite unit; 6: Biomass gasification unit; 7: Second syngas storage tank; 8: Gas detection and flow control unit; 9: Gas purification unit; 10: Syngas to methanol reaction unit; 11: Methanol distillation unit. Detailed Implementation

[0033] The present application will be further described in detail below with reference to the embodiments and examples. It should be understood that these embodiments and examples are only used to illustrate the present application and are not intended to limit the scope of the present application. The purpose of providing these embodiments and examples is to make the disclosure of the present application more thorough and comprehensive.

[0034] It should also be understood that this application can be implemented in many different forms and is not limited to the embodiments and examples described herein. Those skilled in the art can make various alterations or modifications without departing from the spirit of this application, and the resulting equivalent forms also fall within the protection scope of this application. For example, features described or illustrated as part of one embodiment can be combined in a suitable manner in another embodiment to produce new embodiments. Furthermore, numerous specific details are set forth in the following description to provide a fuller understanding of this application; it should be understood that this application can be implemented without one or more of these details.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for descriptive purposes only and is not intended to be limiting of the application.

[0036] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0037] In this application, the terms "multiple", "various", "multiple times", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0038] The terms “combinations of,” “any combination of,” and “any combination of” used in this article include all suitable combinations of any two or more of the listed items.

[0039] In this document, the term "suitable" as used in "suitable combination", "suitable method", "any suitable method", etc., refers to the ability to implement the technical solution of this application, solve the technical problem of this application, and achieve the expected technical effect of this application.

[0040] In this document, terms such as "preferred," "better," "more suitable," and "ideal" are merely descriptions of more effective implementation methods or embodiments, and should be understood not to limit the scope of protection of this application. If multiple "preferred" terms appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "preferred" term shall be independent.

[0041] In this application, terms such as "further," "even further," and "particularly" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0042] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0043] In this application, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0044] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0045] In this application, when numerical intervals (i.e., numerical ranges) are mentioned, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include numerical interval types such as percentage intervals, ratio intervals, and proportion intervals.

[0046] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0047] In this application, the terms "room temperature" or "normal temperature" generally refer to 4℃ to 35℃, for example, 20℃ ± 5℃. In some embodiments of this application, "room temperature" or "normal temperature" refers to 10℃ to 30℃. In some embodiments of this application, "room temperature" or "normal temperature" refers to 20℃ to 30℃.

[0048] In this application, if the unit of a data range is only followed by the right endpoint, it indicates that the units of the left and right endpoints are the same. For example, 3~5 h means that the units of the left endpoint "3" and the right endpoint "5" are both h (hours).

[0049] All references to documents mentioned in this application are incorporated herein by reference as if each document were individually incorporated by reference. Unless they conflict with the inventive purpose and / or technical solution of this application, all cited documents are incorporated herein by reference in their entirety and for all purposes. When citing documents in this application, the definitions of relevant technical features, terms, nouns, phrases, etc., are also incorporated herein by reference. When citing documents in this application, examples and preferred embodiments of the cited technical features may also be incorporated herein by reference, but only to the extent that they enable the implementation of this application. It should be understood that when the cited content conflicts with the description in this application, this application shall prevail or modifications shall be made adaptably to the description in this application.

[0050] The mass or weight of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship of mass or weight between the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass or weight mentioned in the embodiments of this application can be units known in the chemical industry, such as μg, mg, g, and kg.

[0051] The biomass gasification to methanol process includes biomass feedstock pretreatment, gasification, gas conditioning, gas purification, and methanol synthesis and purification. The crude synthesis gas after biomass gasification has a carbon-to-hydrogen ratio of approximately 1:2, which is too high compared to the theoretical carbon-to-hydrogen ratio of 1:4 required for methanol synthesis. The carbon-to-hydrogen ratio needs to be adjusted through water-gas shift reaction or by supplementing with green hydrogen to bring the H2 / CO ratio closer to 2:1. After adjustment, a large amount of renewable CO2 needs to be vented, resulting in a waste of carbon resources. Alternatively, green hydrogen may need to be supplemented through methods such as water electrolysis, which increases costs.

[0052] The biomass fermentation process for methanol production includes several steps, such as biomass feedstock pretreatment, biomass anaerobic fermentation to produce methane, methane steam reforming, gas conditioning, and methanol synthesis and purification. In the methane steam reforming step, methane reacts with steam to produce H2 and CO, with the chemical equation CH4 + H2O = CO + 3H2. The hydrogen in the syngas obtained in this step is excessive for the syngas-to-methanol reaction, requiring the addition of an additional carbon source to increase the carbon-hydrogen ratio, which increases the operational difficulty and cost.

[0053] One embodiment of this application provides a method for producing methanol by coupling biomass gasification and fermentation, comprising the following steps:

[0054] Anaerobic fermentation of the first biomass produces biogas residue and methane;

[0055] Biochar is produced by carbonizing biogas residue.

[0056] Biochar can be reused in anaerobic fermentation;

[0057] Methane and water were reformed to produce the first crude syngas;

[0058] The second biomass is subjected to a gasification reaction to produce a second crude syngas;

[0059] The first crude synthesis gas and the second crude synthesis gas are mixed, and then the resulting mixture is subjected to a hydrogenation reaction to prepare methanol.

[0060] The above-described method for producing methanol by coupling biomass gasification and fermentation involves carbonizing the biochar obtained from the anaerobic fermentation of the first biomass. The resulting biochar has high porosity and numerous reaction sites. Reusing this biochar in anaerobic fermentation effectively promotes electron transfer in the microbial reaction, improving methane production efficiency and yield. Methane and water are reformed to produce a first crude syngas, and the second biomass is gasified to produce a second crude syngas. Both crude and second syngas contain H2 and CO. Compared to the ideal C:H ratio of 1:4 required for methanol synthesis, the first crude syngas contains excess H2, and the second crude syngas contains excess CO. Mixing the first and second crude syngas for hydrogenation produces methanol with low CO2 emissions, effectively improving the carbon efficiency of the biomass feedstock. The biochar is derived from biomass, which is widely available and has low production costs.

[0061] Carbon efficiency: The ratio (usually expressed as a percentage) of the amount of carbon in the target product methanol to the amount of carbon in the biomass feedstock, reflecting the resource utilization efficiency of the directional conversion of carbon in biomass into methanol.

[0062] It is understandable that in some of these examples, in the method of coupling biomass gasification and fermentation to produce methanol, during the first biomass anaerobic fermentation, some biogas residue is separated in real time to produce biochar, and then the biochar is added to the anaerobic fermentation system to continue anaerobic fermentation; it is understandable that only a portion of the biogas residue is made into biochar, and the remaining biogas residue can be used as biomass fertilizer.

[0063] In some of these examples, the anaerobic fermentation conditions in the coupled biomass gasification and fermentation to methanol production methods include a temperature of 35°C to 42°C and a pH of 6.5 to 7.6.

[0064] It is understood that in anaerobic fermentation, the temperature includes, but is not limited to, 35℃, 36℃, 37℃, 38℃, 39℃, 40℃, 41℃, and 42℃; the pH value includes, but is not limited to, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, and 7.6; in some examples, it can be any two of these point values ​​as the end values ​​within a range.

[0065] In some examples, in the method of coupling biomass gasification and fermentation to produce methanol, the carbonization temperature is 350℃~700℃. Optionally, the carbonization time is 1h~3h. It is understood that the carbonization temperature includes, but is not limited to, 350℃, 370℃, 400℃, 420℃, 450℃, 480℃, 500℃, 520℃, 550℃, 580℃, 600℃, 620℃, 650℃, 680℃, and 700℃; and the time includes, but is not limited to, 1h, 1.2h, 1.5h, 1.8h, 2h, 2.2h, 2.5h, 2.8h, and 3h. In some examples, it can be any two of these point values ​​as the endpoints within a range.

[0066] In some examples, in methods coupling biomass gasification and fermentation to methanol, the mass ratio of biochar to the total mass of the first biomass is 1:50 to 100. It is understood that this mass ratio includes, but is not limited to, 1:50, 1:55, 1:60, 1:65, 1:70, 1:75, 1:80, 1:85, 1:90, 1:95, and 1:100. In some examples, it can be a range consisting of any two of these values ​​as endpoints. In some examples, in methods coupling biomass gasification and fermentation to methanol, the first biomass includes at least one of starch and animal manure.

[0067] By controlling the type of primary biomass, the production efficiency and yield of methane can be further improved, as well as the carbon efficiency of the feedstock.

[0068] In some examples, in methods that couple biomass gasification and fermentation to methanol, biochar is recycled into anaerobic fermentation, including:

[0069] Microorganisms were domesticated by attaching and attaching biochar to biochar to obtain a biochar-microbial membrane composite.

[0070] The biochar-microbial membrane complex can be reused in anaerobic fermentation.

[0071] Biofilm acclimatization refers to the process of inoculating microorganisms onto a biochar carrier, allowing the microorganisms to attach, grow, and form a stable biofilm on the surface and within the pores of the biochar, while gradually adapting to the environment and enhancing their functional activity.

[0072] By combining microorganisms with biochar to form a biochar-microbial membrane complex, the porous structure of biochar can provide sheltered sites for microbial colonization, promoting the retention and enrichment of functional microorganisms. At the same time, biochar, as a conductive carbon material, mediates efficient direct interspecies electron transfer, thereby improving the production efficiency and yield of methane.

[0073] Alternatively, the microorganisms include methanogenic archaea.

[0074] Optionally, the microbial loading in the biochar-microbial membrane complex is between 10 mg VSS / g biochar and 150 mg VSS / g biochar. It is understood that the microbial loading includes, but is not limited to, 10 mg VSS / g biochar, 20 mg VSS / g biochar, 50 mg VSS / g biochar, 80 mg VSS / g biochar, 100 mg VSS / g biochar, and 150 mg VSS / g biochar; by controlling the microbial loading, the production efficiency and yield of methane can be further improved.

[0075] In some examples, the total anaerobic fermentation time is 15–25 days. This total time includes the time for anaerobic fermentation of the first biomass directly (without biomass) and the time for recycling biochar into the anaerobic fermentation process. Further, the total anaerobic fermentation time includes, but is not limited to, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, and 25 days. In some examples, it can be a range defined by any two of these point values ​​as endpoints.

[0076] In some of these examples, in methods that couple biomass gasification and fermentation to produce methanol, the second biomass includes at least one of starch, animal manure, wheat straw, corn stalks, and wood.

[0077] In some of these examples, in the coupled biomass gasification and fermentation method for methanol production, the type of the second biomass is the same as the type of the first biomass. In other examples, in the coupled biomass gasification and fermentation method for methanol production, the type of the second biomass is different from the type of the first biomass.

[0078] In some of these examples, in the method of coupling biomass gasification and fermentation to produce methanol, both the first crude syngas and the second crude syngas contain CO and H2, and the volume ratio of CO to H2 in the mixed gas is 1:2 to 2.2. It can be understood that the volume ratio of CO to H2 in the mixed gas is controlled by controlling the mixing ratio of the first and second crude syngas, based on the concentrations of CO and H2 in the first and second crude syngas. Further, the volume ratio of CO to H2 in the mixed gas includes, but is not limited to, 1:2, 1:2.01, 1:2.02, 1:2.03, 1:2.04, 1:2.05, 1:2.06, 1:2.07, 1:2.08, 1:2.09, 1:2.1, 1:2.11, 1:2.12, 1:2.13, 1:2.14, 1:2.15, 1:2.16, 1:2.17, 1:2.18, 1:2.19, and 1:2.2. In some examples, it can be any two of these point values ​​within a range defined by the endpoints.

[0079] In some of these examples, in the method of coupling biomass gasification and fermentation to produce methanol, the reforming reaction temperature is 700°C to 900°C and the pressure is 1 MPa to 3 MPa. It is understood that the reforming reaction temperature includes, but is not limited to, 700℃, 710℃, 720℃, 730℃, 740℃, 750℃, 760℃, 770℃, 780℃, 790℃, 800℃, 810℃, 820℃, 830℃, 840℃, 850℃, 860℃, 870℃, 880℃, 890℃, and 900℃, and the pressure includes, but is not limited to, 1 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, 1.6 MPa, 1.7 MPa, 1.8 MPa, 1.9 MPa, 2 MPa, 2.1 MPa, 2.2 MPa, 2.3 MPa, 2.4 MPa, 2.5 MPa, 2.6 MPa, 2.7 MPa, 2.8 MPa, 2.9 MPa, and 3 MPa. MPa; in some examples, this can be a range consisting of any two of these point values ​​as endpoints.

[0080] In some of these examples, in the method of coupling biomass gasification and fermentation to produce methanol, the gasification reaction temperature is 900℃~1200℃ and the pressure is 0.1 MPa~3 MPa. It is understood that the temperatures of the gasification reaction include, but are not limited to, 900℃, 910℃, 920℃, 930℃, 940℃, 950℃, 960℃, 970℃, 980℃, 990℃, 1000℃, 1010℃, 1020℃, 1030℃, 1040℃, 1050℃, 1060℃, 1070℃, 1080℃, 1090℃, 1100℃, 1110℃, 1120℃, 1130℃, 1140℃, 1150℃, 1160℃, 1170℃, 1180℃, 1190℃, and 1200℃, and the pressures include, but are not limited to, 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, and 1... MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, 1.6 MPa, 1.7 MPa, 1.8 MPa, 1.9 MPa, 2 MPa, 2.1 MPa, 2.2 MPa, 2.3 MPa, 2.4 MPa, 2.5 MPa, 2.6 MPa, 2.7 MPa, 2.8 MPa, 2.9 MPa, 3 MPa; in some examples, any two of these point values ​​can be used as endpoints within a range.

[0081] In some of these examples, the method of coupling biomass gasification and fermentation to produce methanol includes, before the hydrogenation reaction, removing H2S and CO2 from the mixed gas and then hydrogenating the resulting purified syngas.

[0082] In some of these examples, the method of coupling biomass gasification and fermentation to produce methanol includes a step of purifying the crude methanol by distillation after the hydrogenation reaction.

[0083] The method for producing methanol by coupling biomass gasification and fermentation provided in this application involves preparing a biochar-microbial membrane composite by attaching and acclimating microorganisms to biochar prepared from biogas residue, which is then reused in anaerobic fermentation. This improves methane yield. By controlling the flow rates of the crude syngas obtained from biomass gasification and fermentation, the two gases are mixed in a specific ratio, resulting in a carbon-to-hydrogen ratio of approximately 1:4, which is ideal for methanol synthesis. This method avoids the technical problems of venting large amounts of renewable CO2, requiring additional green hydrogen / carbon dioxide, or needing to supplement environmentally unfriendly reagents such as iron.

[0084] See Figure 1One embodiment of this application provides a system for coupling biomass gasification and fermentation to produce methanol, including a biomass anaerobic fermentation unit 1, a methane steam reforming reactor 2, a first syngas storage tank 3, a biogas residue carbonization unit 4, a biochar-microorganism composite unit 5, a biomass gasification unit 6, a second syngas storage tank 7, a gas detection and flow control unit 8, a gas purification unit 9, a syngas-to-methanol reactor 10, and a methanol distillation unit 11. The output end of the biomass anaerobic fermentation unit is sequentially connected to the methane steam reforming reactor, the first syngas storage tank, and the gas detection and flow control unit. The devices are connected in sequence. The biogas residue output end of the biomass anaerobic fermentation device is connected to the biogas residue carbonization device and the biochar-microorganism composite device in sequence. The biochar-microorganism membrane composite output end of the biochar-microorganism composite device returns to the biomass anaerobic fermentation device. The output end of the biomass gasification device is connected to the second syngas storage tank and the gas detection and flow control device in sequence. The output end of the gas detection and flow control device is connected to the gas purification device. The output end of the gas purification device is connected to the syngas to methanol reaction device. The output end of the syngas to methanol reaction device is connected to the methanol distillation device.

[0085] Understandably, in some examples, the first biomass enters a biomass anaerobic fermentation unit for anaerobic digestion, yielding methane and biogas residue; a portion of the biogas residue enters a biogas residue carbonization unit for carbonization, and the resulting biochar enters a biochar-microorganism composite unit, where it is combined to form a biochar-microorganism membrane composite, which then enters the anaerobic fermentation unit, increasing the rate and yield of biogas production; methane and water enter a methane steam reforming reactor for reforming, producing a first crude syngas which is stored in a first syngas storage tank; the second biomass and oxygen... The first and second crude syngas enter a biomass gasification unit and undergo a gasification reaction to produce a second crude syngas. The first and second crude syngas then enter a gas detection and flow control device to detect the concentrations of CO and H2 in the first and second crude syngas, and adjust the mixing ratio of the first and second crude syngas. The resulting mixed gas enters a gas purification device to remove H2S and CO2, obtaining purified syngas. The purified syngas enters a syngas-to-methanol reactor and undergoes a hydrogenation reaction to obtain crude methanol. The crude methanol enters a methanol distillation unit to obtain the methanol product.

[0086] The methanol production system coupled with biomass gasification and fermentation provided in this application is used to produce methanol. It has high biomass carbon utilization efficiency, is environmentally friendly, and has low cost.

[0087] The present application will be described in further detail below with reference to specific embodiments, but the embodiments of the present application are not limited thereto.

[0088] Example 1

[0089] (1) The first biomass (animal manure) enters the biomass anaerobic fermentation device and undergoes anaerobic digestion (temperature is 38℃, pH value is 7.0), producing methane and biogas residue;

[0090] (2) Part of the biogas residue is fed into the biogas residue carbonization device for carbonization treatment (temperature is 400℃, time is 2h), and the biochar obtained is fed into the biochar-microorganism composite device. Methanogenic archaea are attached to the biochar and domesticated to obtain a biochar-microorganism film composite, which is then fed into the anaerobic fermentation device in step (1). In the biochar-microorganism film composite, the microbial loading is 80 mg VSS / g biochar, and the ratio of the mass of biochar to the total mass of the first biomass is 1:50.

[0091] (3) The total fermentation time is 15 days. The generated methane and water are put into the methane steam reforming reactor for reforming reaction (temperature is 900℃, pressure is 1 MPa) to produce the first crude syngas and store it in the first syngas storage tank.

[0092] (4) The second biomass (animal manure) and oxygen enter the biomass gasification device to undergo a gasification reaction (temperature is 900℃, pressure is 1 MPa) to produce the second crude syngas;

[0093] (5) The first crude syngas and the second crude syngas enter the gas detection and flow control device to detect the concentrations of CO and H2 in the first crude syngas and the second crude syngas, and adjust the mixing ratio of the first crude syngas and the second crude syngas so that the volume ratio of CO to H2 in the mixed gas is about 1:2; the resulting mixed gas enters the gas purification device to remove H2S and CO2, and obtain purified syngas; the purified syngas enters the syngas to methanol reaction device to undergo hydrogenation reaction, and obtain crude methanol; the crude methanol enters the methanol distillation device to obtain methanol product.

[0094] Example 2

[0095] The difference from Example 1 is that the first biomass (animal feces) in step (1) of Example 1 is replaced with starch.

[0096] Example 3

[0097] The difference from Example 1 is that the second biomass (animal manure) in step (4) of Example 1 is replaced with corn stalks.

[0098] Example 4

[0099] The difference from Example 1 is that the methanogenic archaea in step (2) of Example 1 are omitted, and biochar is directly added to the biomass anaerobic fermentation device in step (1).

[0100] Example 5

[0101] The difference from Example 1 is that in Example 5, the methanogenic archaea in step (2) of Example 1 are omitted, and the same mass of methanogenic archaea as in step (2) of Example 1 is added to the biomass anaerobic fermentation device in step (1), and biochar is directly added to the biomass anaerobic fermentation device in step (1) in step (2).

[0102] Comparative Example 1

[0103] The difference from Example 1 is that step (2) in Example 1 is omitted.

[0104] The results showed that, in Comparative Example 1, the anaerobic fermentation did not use a biochar-microbial membrane complex, while in Examples 1-3, the biomass sludge obtained from anaerobic fermentation was carbonized, and the resulting biochar was then combined with methanogenic archaea. The resulting biochar-microbial membrane complex was used for anaerobic fermentation, which significantly improved the methane yield. Compared to Comparative Example 1, Examples 1-3 improved the methane yield by approximately 26%, 20%, and 17%, respectively. In Example 4, the methanogenic archaea were omitted, and only biochar was added. In Example 5, the methanogenic archaea were not combined with biochar before being directly added to the biomass anaerobic fermentation device in step (1). Compared to Comparative Example 1, Examples 4 and 5 improved the methane yield by approximately 8% and 14%, respectively.

[0105] Furthermore, this application couples biomass gasification and fermentation to produce methanol. Compared to biomass gasification, this process eliminates the need to vent renewable CO2 or add hydrogen, and compared to biomass fermentation, it eliminates the need to add CO2, thus improving environmental benefits and overall process economics. Moreover, CO2 emissions during production are minimal, resulting in high carbon efficiency of the biomass feedstock. The biochar-microbial membrane complex, obtained by combining biochar produced from biomass fermentation residue with microorganisms, keeps functional microbial agents within the reaction system, increasing intercellular contact, reducing matrix transfer limitations, and enhancing inoculation efficiency. Additionally, the adjacent biochar acts as an exogenous electron acceptor, promoting interspecies electron transfer between methanogens and symbiotic bacteria, thereby improving methanogenesis efficiency and yield. Since the biochar originates from biomass feedstock, it is more environmentally friendly than adding metal salt solutions as methane promoters. In summary, this application addresses the problems of low biomass feedstock carbon efficiency, narrow applicability of biomass feedstocks, high production costs, and environmental unfriendliness in traditional biomass-to-methanol processes, thereby improving environmental benefits and overall process economics.

[0106] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0107] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for producing methanol by coupling biomass gasification and fermentation, characterized in that, Includes the following steps: Anaerobic fermentation of the first biomass produces biogas residue and methane; The biochar is prepared by carbonizing the biogas residue. The biochar is reused in the anaerobic fermentation. The methane was reformed with water to produce the first crude syngas; The second biomass is subjected to a gasification reaction to produce a second crude syngas; The first crude synthesis gas and the second crude synthesis gas are mixed, and then the resulting mixture is subjected to a hydrogenation reaction to prepare methanol.

2. The method for producing methanol by coupling biomass gasification and fermentation as described in claim 1, characterized in that, The method satisfies at least one of the following characteristics: (1) The conditions for anaerobic fermentation include: temperature of 35℃~42℃ and pH value of 6.5~7.6; (2) The carbonization temperature is 350℃~700℃.

3. The method for producing methanol by coupling biomass gasification and fermentation as described in claim 1, characterized in that, The first biomass includes at least one of starch and animal feces.

4. The method for producing methanol by coupling biomass gasification and fermentation as described in claim 1, characterized in that, Reusing the biochar in the anaerobic fermentation includes: Microorganisms were domesticated by attaching and forming a membrane on the biochar to obtain a biochar-microbial membrane composite. The biochar-microbial membrane complex is reused in the anaerobic fermentation. Optionally, the microorganisms include methanogenic archaea.

5. The method for producing methanol by coupling biomass gasification and fermentation as described in claim 1, characterized in that, The second biomass includes at least one of starch, animal manure, wheat straw, corn stalks, and wood.

6. The method for producing methanol by coupling biomass gasification and fermentation as described in any one of claims 1 to 5, characterized in that, Both the first crude synthesis gas and the second crude synthesis gas contain CO and H2, and the volume ratio of CO to H2 in the mixed gas is 1:2 to 2.

2.

7. The method for producing methanol by coupling biomass gasification and fermentation as described in any one of claims 1 to 5, characterized in that, The reforming reaction is carried out at a temperature of 700℃ to 900℃ and a pressure of 1 MPa to 3 MPa.

8. The method for producing methanol by coupling biomass gasification and fermentation as described in any one of claims 1 to 5, characterized in that, The temperature of the gasification reaction is 900℃~1200℃, and the pressure is 0.1 MPa~3 MPa.

9. The method for producing methanol by coupling biomass gasification and fermentation as described in any one of claims 1 to 5, characterized in that, Before the hydrogenation reaction, the process further includes: removing H2S and CO2 from the mixed gas, and then subjecting the purified syngas to the hydrogenation reaction.

10. A system for coupling biomass gasification and fermentation to produce methanol, characterized in that, The system includes a biomass anaerobic fermentation unit, a methane steam reforming reactor, a first syngas storage tank, a biogas residue carbonization unit, a biochar-microorganism composite unit, a biomass gasification unit, a second syngas storage tank, a gas detection and flow control device, a gas purification device, a syngas-to-methanol reactor, and a methanol distillation unit. The output of the biomass anaerobic fermentation unit is sequentially connected to the methane steam reforming reactor, the first syngas storage tank, and the gas detection and flow control device. The biogas residue output of the biomass anaerobic fermentation unit is sequentially connected to the biogas residue carbonization unit and the biochar-microorganism composite unit. The biochar-microorganism membrane composite output of the biochar-microorganism composite unit returns to the biomass anaerobic fermentation unit. The output of the biomass gasification unit is sequentially connected to the second syngas storage tank and the gas detection and flow control device. The output of the gas detection and flow control device is connected to the gas purification device. The output of the gas purification device is connected to the syngas-to-methanol reactor. The output of the syngas-to-methanol reactor is connected to the methanol distillation unit.

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