System and method for preparing green methanol from biomass coupled green hydrogen

Abstract

The invention relates to the technical field of energy utilization, in particular to a system and method for preparing green methanol from biomass coupled green hydrogen, and the system comprises a water electrolysis hydrogen production device, a biomass gasification device, a biomass direct combustion device, a biomass power generation device and a methanol synthesis device, oxygen generated by the water electrolysis hydrogen production device is communicated with the biomass gasification device, hydrogen generated by the water electrolysis hydrogen production device, and the biomass gasification device and the biomass direct combustion device are communicated with the methanol synthesis device; and the biomass direct combustion device is connected with the biomass power generation device. According to the system for preparing the green methanol by coupling the biomass and the green hydrogen, the biomass is converted into the green methanol, high-value utilization of biomass resources can be achieved, and convenient conditions can be provided for long-distance conveying of products and absorption of wind, light and green electricity.

Description

Technical Field

[0001] The present invention relates to the technical field of energy utilization, and in particular to a system and method for producing green methanol by coupling biomass with green hydrogen. Background Art

[0002] It is urgent to promote the transformation and development of low-carbon energy. The efficient development and utilization of biomass energy is generally considered to be an important means to promote emission reduction in the energy industry, ensure energy security and seek sustainable development. Biomass can be used to produce high-value products such as activated carbon, bio-jet fuel, and methanol. Among them, methanol is the most widely used. It can be used as a liquid fuel and can also be widely used as a chemical raw material in the chemical, building materials, textile and other industries. However, in the traditional process of producing methanol, the operating energy consumption accounts for a large proportion of the entire process.

[0003] Biomass is considered to be the fourth largest energy source after coal, oil and natural gas, and has shown new advantages in recent years. Due to the advantages of biomass resources, biomass to methanol (BTM) technology has become a major research hotspot in recent years. The synthesis gas produced by pyrolysis of biomass in a dedicated biomass gasifier is used as an intermediate product, and then methanol is synthesized through catalytic conversion, but the conversion system requires additional steam consumption and discharges some CO2, resulting in a reduced utilization rate of renewable carbon sources.

[0004] my country is rich in solar and wind energy resources, with annual solar radiation values ​​of about 1050-2450kW·h, and areas with radiation values ​​greater than 1050kW·h account for more than 96% of the country's land area. Wind and solar energy resources are volatile and unstable in time and season, which puts pressure on grid dispatch and becomes a huge problem that hinders the connection of clean energy to the grid. Using renewable energy such as wind or solar energy to generate electricity can effectively accelerate the transition away from the fossil fuel economy and promote sustainable development. However, a single solar or wind energy system depends on the weather, and the unpredictability of weather changes will reduce the reliability of the system, resulting in a more serious problem of "abandoning wind and light".

[0005] Currently, only 4% of hydrogen is obtained through water electrolysis. Compared with traditional fossil energy hydrogen production, it has the advantages of simple process, no pollution, and high hydrogen purity. However, the high cost of water electrolysis hydrogen production technology has greatly limited its use. Using renewable energy power generation (such as wind power and photovoltaic power) to produce water electrolysis hydrogen, and synthesizing methanol from CO2 captured by water electrolysis hydrogen and CO2 capture technology is one of the effective ways to solve the problem of power abandonment in new energy power generation, but the cost of this technical route is too high and the technical and economic performance is poor.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The purpose of the present invention is to provide a biomass-coupled green hydrogen system and method for producing green methanol. The biomass-coupled green hydrogen system for producing green methanol utilizes the conversion of biomass into green methanol, which can realize the high-value utilization of biomass resources and provide convenient conditions for long-distance transportation of products and consumption of wind and solar green electricity.

[0008] In a first aspect, the present invention provides a biomass-coupled green hydrogen-to-green methanol system, comprising a water electrolysis hydrogen production device, a biomass gasification device, a biomass direct combustion device, a biomass power generation device, and a methanol synthesis device.

[0009] Among them, the oxygen produced by the water electrolysis hydrogen production device is connected to the biomass gasification device, the hydrogen produced by the water electrolysis hydrogen production device, the biomass gasification device and the biomass direct combustion device are all connected to the methanol synthesis device; the biomass direct combustion device is connected to the biomass power generation device.

[0010] As a preferred embodiment of the present technical solution, it further comprises a biomass gasification product purification device and a biomass gasification product separation device, wherein the biomass gasification device, the biomass gasification product purification device, the biomass gasification product separation device and the methanol synthesis device are sequentially connected.

[0011] As a preferred embodiment of the present technical solution, it further comprises a carbon dioxide gas capture device and a methane gas capture device, and the biomass direct combustion device, the carbon dioxide gas capture device and the methanol synthesis device are connected in sequence.

[0012] As a preferred embodiment of the present technical solution, a methane reforming reactor is further included, and the biomass gasification product separation device and the methane gas capture device are both connected to the methane reforming reactor.

[0013] As a preferred embodiment of the present technical solution, the methanol synthesis device includes a first booster pump, a first synthesis tower, a first gas-liquid separator, a second booster pump, a second synthesis tower and a second gas-liquid separator.

[0014] The biomass gasification product separation device, the first booster pump, the first synthesis tower and the first gas-liquid separator are connected in sequence;

[0015] The carbon dioxide gas capture device, the second booster pump, the second synthesis tower and the second gas-liquid separator are connected in sequence;

[0016] The hydrogen generated by the water electrolysis hydrogen production device is connected to the first booster pump and the second booster pump;

[0017] The first gas-liquid separator and the second gas-liquid separator are respectively connected to the first synthesis tower and the second synthesis tower in reverse direction;

[0018] The methane reforming reactor is in communication with the first synthesis tower.

[0019] As a preferred embodiment of the present technical solution, it further comprises a methanol distillation device, and the first gas-liquid separator and the second gas-liquid separator are both connected to the methanol distillation device.

[0020] As a preferred embodiment of the present technical solution, it also includes a wind-solar complementary power generation device, and the wind-solar complementary power generation device supplies power to the water electrolysis hydrogen production device.

[0021] In a second aspect, the present invention further discloses a method for producing green methanol using the above-mentioned biomass coupled green hydrogen to green methanol system, comprising the following steps:

[0022] Hydrogen and oxygen are produced by electrolyzing water to produce hydrogen;

[0023] The oxygen produced by the water electrolysis hydrogen production device is transported to the biomass gasification device as the raw gas for biomass gasification. The gasification gas produced by the biomass gasification is purified and separated to obtain carbon monoxide and hydrogen produced by the water electrolysis hydrogen production device, which are transported to the first synthesis tower to obtain crude methanol.

[0024] The carbon dioxide produced by direct combustion of biomass and the hydrogen produced by the water electrolysis hydrogen production device are transported to the second synthesis tower to obtain crude methanol;

[0025] The methane gas obtained after purification and separation of the gasification gas produced by biomass gasification, the methane gas produced by direct combustion of biomass and water are transported to the methane reforming reactor, and the generated carbon monoxide and hydrogen are transported to the first synthesis tower;

[0026] The crude methanol produced by the first synthesis tower and the second synthesis tower is transported to the methanol distillation unit, and dark green bio-methanol is obtained through distillation.

[0027] As a preferred embodiment of the present technical solution, in the methane reforming reactor, the reaction temperature is 600-800°C, the reaction pressure is 2-5MPa, and the catalyst is any one of nickel, rhodium, platinum and palladium or its oxide.

[0028] As a preferred embodiment of the present technical solution, in the first synthesis tower, the reaction temperature is 200-300°C, the reaction pressure is 1-10MPa, and the catalyst is an oxide of any one of copper, zinc and chromium;

[0029] In the second synthesis tower, the reaction temperature is 200-300°C, the reaction pressure is 20-100MPa, and the catalyst is an oxide of any one of copper, zinc and chromium.

[0030] The biomass-coupled green hydrogen-to-green methanol system of the present invention has at least the following beneficial effects:

[0031] The biomass-coupled green hydrogen-to-green methanol system of the present invention includes a water electrolysis hydrogen production device, a biomass gasification device, a biomass direct combustion device, a biomass power generation device, and a methanol synthesis device. The present invention uses a water electrolysis hydrogen production device to prepare high-purity hydrogen and oxygen, and then transports the prepared oxygen to the biomass gasification device as a raw gas for biomass gasification. The biomass undergoes pyrolysis, oxidation, and reduction reforming reactions under high-temperature oxygen-deficient conditions to generate combustible gases such as carbon monoxide, hydrogen, and methane. Therefore, the methanol synthesis device can directly synthesize methanol using the hydrogen produced in the water electrolysis hydrogen production device and the carbon monoxide produced in the biomass gasification device. At the same time, the carbon dioxide produced by the complete combustion of biomass in the biomass direct combustion device and the hydrogen produced in the water electrolysis hydrogen production device can also be further directly synthesized into methanol by the methanol synthesis device. Finally, the biomass power generation device uses the biomass direct combustion device to generate electricity to achieve off-grid green electricity supply. Therefore, the biomass-coupled green hydrogen-to-green methanol system of the present invention utilizes the conversion of biomass into green methanol, which can achieve high-value utilization of biomass resources and provide convenient conditions for long-distance transportation of products and consumption of wind and solar green electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 It is a schematic diagram of the biomass-coupled green hydrogen production system for green methanol of the present invention;

[0034] Figure 2 This is the technical roadmap for producing green methanol by coupling biomass with green hydrogen in the present invention.

[0035] Reference numerals:

[0036] 1: Water electrolysis hydrogen production device; 2: Biomass gasification device; 3: Biomass direct combustion device; 4: Biomass power generation device; 5: Biomass gasification product purification device; 6: Carbon dioxide gas capture device; 7: First booster pump; 8: First synthesis tower; 9: First gas-liquid separator; 10: Second booster pump; 11: Second synthesis tower; 12: Second gas-liquid separator; 13: Crude methanol storage device; 14: Distillation tower; 15: Dark green biomethanol storage device. DETAILED DESCRIPTION

[0037] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0038] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0039] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Example 1

[0041] like Figure 1-2 As shown, this embodiment provides a biomass-coupled green hydrogen to green methanol system, comprising a water electrolysis hydrogen production device 1, a biomass gasification device 2, a biomass direct combustion device 3, a biomass power generation device 4 and a methanol synthesis device, wherein the oxygen generated by the water electrolysis hydrogen production device 1 is connected to the biomass gasification device 2, and the hydrogen generated by the water electrolysis hydrogen production device 1, the biomass gasification device 2 and the biomass direct combustion device 3 are all connected to the methanol synthesis device; the biomass direct combustion device 3 is connected to the biomass power generation device 4.

[0042] The biomass coupled green hydrogen to green methanol system of the present invention comprises a water electrolysis hydrogen production device 1, a biomass gasification device 2, a biomass direct combustion device 3, a biomass power generation device 4 and a methanol synthesis device. The present invention uses the water electrolysis hydrogen production device 1 to prepare high-purity hydrogen and oxygen, and then transports the prepared oxygen to the biomass gasification device 2 as a raw gas for biomass gasification. The biomass undergoes pyrolysis, oxidation, and reduction reforming reactions under high-temperature anoxic conditions to generate combustible gases such as carbon monoxide, hydrogen, and methane. Therefore, the methanol synthesis device uses the hydrogen generated in the water electrolysis hydrogen production device 1 and the carbon monoxide generated in the biomass gasification device 2 to directly synthesize methanol. At the same time, the carbon dioxide generated by the complete combustion of biomass in the biomass direct combustion device 3 and the methanol synthesis device using the hydrogen generated in the water electrolysis hydrogen production device 1 can also be further directly synthesized into methanol. Finally, the biomass power generation device 4 uses the biomass direct combustion device 3 to generate electricity to realize off-grid green electricity supply.

[0043] Therefore, the biomass-coupled green hydrogen-to-green methanol system of the present invention utilizes the conversion of biomass into green methanol, which can achieve high-value utilization of biomass resources and provide convenient conditions for long-distance transportation of products and consumption of wind and solar green electricity.

[0044] On the basis of the above technical scheme, further, it also includes a biomass gasification product purification device 5 and a biomass gasification product separation device, and the biomass gasification device 2, the biomass gasification product purification device 5, the biomass gasification product separation device and the methanol synthesis device are connected in sequence. The biomass gasification device 2 uses biomass raw materials (such as wood chips, sawdust, wheat straw, rice straw, etc.) for gasification reaction. Specifically, in the biomass gasification device 2, the biomass raw materials undergo pyrolysis, oxidation, reduction and reforming reactions under high temperature and oxygen deficiency conditions to generate combustible gases (such as carbon monoxide, hydrogen, methane, etc.) and ash. In addition, the biomass gasification product may also contain impurities such as tar and dust, and the biomass gasification product purification device 5 is mainly used to remove solid particles and tar components in the biomass gasification product. The purified biomass gasification product needs to be separated to obtain gases of different components, and the biomass gasification product separation device of the present invention mainly separates gases such as carbon monoxide, hydrogen, and methane by compression, condensation, adsorption, etc. Finally, the methanol synthesis device uses the separated carbon monoxide and the hydrogen produced by the water electrolysis hydrogen production device 1 as raw materials, and performs a synthesis reaction through the action of a catalyst to produce methanol. The entire process achieves efficient conversion and utilization of biomass while reducing environmental pollution.

[0045] Specifically, the biomass gasification device 2 in this embodiment includes a gasifier and a feeding and conveying device, among which the gasifier is the main equipment for biomass gasification, which is divided into two categories: a fixed bed gasifier and a fluidized bed gasifier; the feeding and conveying device is used to feed the biomass raw materials into the gasifier.

[0046] The biomass gasification product purification device 5 in this embodiment includes a dust collector and a tar removal device, wherein the dust collector may be a bag dust collector, a cyclone dust collector, etc., and the tar removal device may be a condenser, a scrubber, etc.

[0047] The biomass gasification product separation device in this embodiment includes a gas compressor, a condenser and an adsorption tower, among which the gas compressor is used to increase the pressure of the gas for subsequent processing; the condenser is used to condense the gas into liquid for separation; and the adsorption tower mainly uses an adsorbent to separate the gas.

[0048] On the basis of the above technical solution, it is further preferred that a carbon dioxide gas capture device 6 and a methane gas capture device are further included, and the biomass direct combustion device 3, the carbon dioxide gas capture device 6 and the methanol synthesis device are connected in sequence.

[0049] In the present embodiment, the biomass direct combustion device 3 converts the chemical energy stored in the biomass into the internal energy of high-temperature and high-pressure steam through boiler combustion, and then drives the subsequent biomass power generation device 4 to generate electricity to realize off-grid green electricity supply. During the biomass combustion process, the carbon element in the biomass combines with oxygen to generate carbon dioxide, and releases water vapor and other gases. The carbon dioxide capture device mainly uses specific adsorbents (such as activated carbon, molecular sieves, nanoporous hybrid materials and metal organic framework materials, etc.) to adsorb and separate carbon dioxide. After being processed by the carbon dioxide capture device, the high-concentration carbon dioxide gas obtained can be transported to the methanol synthesis device by pipeline for use. This process realizes the efficient conversion and utilization of biomass, while reducing the emission of carbon dioxide, and producing valuable chemical raw material methanol.

[0050] On the basis of the above technical solution, more preferably, it further comprises a methane reforming reactor, and the biomass gasification product separation device and the methane gas capture device are both connected to the methane reforming reactor.

[0051] Biomass gasification is the process of reacting biomass raw materials with oxygen at high temperatures to convert them into carbon monoxide (CO), hydrogen (H2), methane (CH4), carbon dioxide (CO2) and a small amount of other hydrocarbon gases and impurities. The biomass gasification product separation device separates these gas mixtures. Among the separated gases, methane is collected separately as a valuable fuel gas and sent to a methane gas capture device for further capture and purification. Specifically, the methane gas capture device can capture and purify methane through adsorbents or membrane materials. After being processed by the capture device, a high concentration of methane gas is obtained, and this part of the methane gas is sent to a methane reforming reactor for further conversion.

[0052] The methane reforming reactor is a key device in the methane conversion process. In the methane reforming reactor, methane and water vapor or carbon dioxide undergo a reforming reaction under the action of high temperature and catalyst to generate carbon monoxide and hydrogen. The reforming reaction specifically includes methane steam reforming or methane carbon dioxide reforming:

[0053] Methane steam reforming reaction: CH4+H2O→CO+3H2

[0054] Methane carbon dioxide reforming reaction: CH4+CO2→2CO+2H2

[0055] Finally, the mixture of carbon monoxide and hydrogen produced in the methane reforming reactor can be sent again to the methane synthesis unit to synthesize methanol.

[0056] In this embodiment, the methanol synthesis device specifically includes a first booster pump 7, a first synthesis tower 8, a first gas-liquid separator 9, a second booster pump 10, a second synthesis tower 11 and a second gas-liquid separator 12.

[0057] Among them, the biomass gasification product separation device, the first booster pump 7, the first synthesis tower 8 and the first gas-liquid separator 9 are connected in sequence, and the hydrogen produced by the water electrolysis hydrogen production device 1 is reversely connected to the first booster pump 7, and the first gas-liquid separator 9 is reversely connected to the first synthesis tower 8; that is, the combustible gas produced by the biomass gasification device 2 is treated by the biomass gasification product separation device to produce carbon monoxide and the hydrogen produced by the water electrolysis hydrogen production device 1 are pressurized by the first booster pump 7 and then enter the first synthesis tower 8. The resulting synthesis product is separated into gas and liquid by the first gas-liquid separator 9, and the resulting liquid product is methanol, and the gas is further transported to the first synthesis tower 8 to continue the reaction.

[0058] The carbon dioxide gas capture device 6, the second booster pump 10, the second synthesis tower 11 and the second gas-liquid separator 12 are connected in sequence, the hydrogen produced by the water electrolysis hydrogen production device 1 is connected to the second booster pump 10, and the second gas-liquid separator 12 is reversely connected to the second synthesis tower 11; that is, the high-concentration carbon dioxide captured by the carbon dioxide gas capture device 6 and the hydrogen produced by the water electrolysis hydrogen production device 1 are pressurized by the second booster pump 10 and then enter the second synthesis tower 11, the obtained synthesis product is separated into gas and liquid by the second gas-liquid separator 12, the obtained liquid product is methanol, and the gas is further transported to the second synthesis tower 11 to continue the reaction.

[0059] The methane reforming reactor is connected to the first synthesis tower 8, and the carbon monoxide and hydrogen mixture obtained by the methane reforming reactor can also be further transported to the first synthesis tower 8 to produce methanol.

[0060] In addition, in order to further improve the purity of methanol produced by the methanol synthesis device, the biomass-coupled green hydrogen-to-green methanol system of this embodiment also includes a methanol distillation device. At this time, the first gas-liquid separator 9 and the second gas-liquid separator 12 are both connected to the methanol distillation device.

[0061] Specifically, the methanol distillation device in this embodiment includes a crude methanol storage device 13 , a distillation tower 14 and a dark green biomethanol storage device 15 .

[0062] On the basis of the above technical solution, more preferably, a wind-solar complementary power generation device is also included, and the wind-solar complementary power generation device here can supply power to the water electrolysis hydrogen production device 1, thereby providing convenient conditions for the consumption of wind-solar green electricity and reducing the cost of water electrolysis hydrogen production. In addition, the combination of wind and solar energy greatly improves the operability and predictability of power supply, and the solar and wind complementary power generation system is more superior in economic and technical performance than a single solar or wind power generation system.

[0063] Example 2

[0064] This embodiment discloses a method for producing green methanol using the above-mentioned biomass coupled green hydrogen to green methanol system, which specifically includes the following steps:

[0065] Producing hydrogen and oxygen by means of a water electrolysis hydrogen production device 1;

[0066] The oxygen produced by the water electrolysis hydrogen production device 1 is transported to the biomass gasification device 2 as the raw gas for biomass gasification. The gasification gas produced by the biomass gasification is purified and separated to obtain carbon monoxide and hydrogen produced by the water electrolysis hydrogen production device 1. The first synthesis tower 8 is used to obtain crude methanol. The reaction temperature of the first synthesis tower 8 is 200-300°C, the reaction pressure is 1-10MPa, and the catalyst is an oxide of any one of copper, zinc and chromium. In addition, in order to further improve the reaction efficiency of the first synthesis tower 8, the volume fraction of carbon monoxide is controlled at 20-30%. %, and the molar ratio of carbon monoxide to hydrogen is controlled at about 1:2 to ensure efficient reaction; at the specific reaction temperature of the first synthesis tower 8 in this embodiment, the selectivity of the reaction and the purity of the product can be effectively improved, and the reaction pressure is set to 1-10MPa. A higher pressure is conducive to the balance of the methanol synthesis reaction moving toward the product direction, thereby improving the yield of the product. Finally, the catalyst uses an oxide of any one of copper, zinc and chromium. These catalysts have good catalytic activity for the methanol synthesis reaction, can reduce the activation energy of the reaction, and increase the reaction rate.

[0067] The carbon dioxide generated by direct combustion of biomass and the hydrogen produced by the electrolytic water hydrogen production device 1 are transported to the second synthesis tower 11 to obtain crude methanol, wherein the reaction temperature of the second synthesis tower 11 is 200-300°C, the reaction pressure is 20-100MPa, and the catalyst is an oxide of any one of copper, zinc and chromium; in addition, in order to further improve the reaction efficiency of the second synthesis tower 11, the volume fraction of carbon dioxide is controlled at 25-33.3%, and the molar ratio of carbon dioxide to hydrogen is controlled at about 1:3 to ensure efficient reaction; at the specific reaction temperature of the first synthesis tower 8 in this embodiment, the selectivity of the reaction and the purity of the product can be effectively improved, and the reaction pressure is set to 20-100MPa, which is much higher than the pressure range of the conventional methanol synthesis reaction. Although this high-pressure technology has high requirements on equipment, it can bring significant economic benefits.

[0068] The methane gas obtained by the gasification gas produced by biomass gasification is purified and separated, and the methane gas and water produced by the direct combustion of biomass are transported to the methane reforming reactor, and the generated carbon monoxide and hydrogen are transported to the first synthesis tower 8, wherein, in the methane reforming reactor, the reaction temperature is 600-800°C, the reaction pressure is 2-5MPa, and the catalyst is any one of nickel, rhodium, platinum and palladium or its oxide; in the methane reforming reactor, the reaction temperature is set to 600-800°C, this temperature range can ensure the efficient progress of the methane reforming reaction, and the high temperature condition is conducive to the cracking and reforming of methane, thereby generating a large amount of carbon monoxide and hydrogen; and the reaction pressure is controlled at 2-5MPa, which is conducive to the reaction in the direction of generating carbon monoxide and hydrogen, thereby improving the conversion rate of the reaction and the selectivity of the product. This embodiment not only utilizes the methane gas produced by biomass gasification, but also utilizes the methane gas produced by direct combustion of biomass, thereby maximizing the utilization of biomass resources. Through the methane reforming reaction, methane is converted into high-value-added chemical raw materials (carbon monoxide and hydrogen), thereby improving the economic value and environmental benefits of biomass resources.

[0069] Finally, the crude methanol produced by the first synthesis tower 8 and the second synthesis tower 11 is transported to a methanol distillation device, and after distillation, dark green biomethanol can be obtained.

[0070] Taking the green methanol production capacity of 200,000 tons / year as an example, the total investment of the model is 5.45 billion yuan, the project covers an area of ​​300-400 acres, the annual consumption of high calorific value biomass resources such as crop straw, forest understory, pruned branches and fallen leaves is 374,000 tons, the green electricity installed capacity is 500MW, and the annual production of green methanol is 200,000 tons. The main indicators of the model are shown in Table 1.

[0071] Table 1 Main indicators of biomass gasification + direct combustion coupled with wind and photovoltaic power to produce 200,000 tons of green methanol per year

[0072]

[0073]

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A biomass-coupled green hydrogen-to-green methanol system, characterized in that: It comprises a water electrolysis hydrogen production device (1), a biomass gasification device (2), a biomass direct combustion device (3), a biomass power generation device (4) and a methanol synthesis device. The oxygen generated by the water electrolysis hydrogen production device (1) is connected to the biomass gasification device (2), the hydrogen generated by the water electrolysis hydrogen production device (1), the biomass gasification device (2) and the biomass direct combustion device (3) are all connected to the methanol synthesis device; the biomass direct combustion device (3) is connected to the biomass power generation device (4).

2. The biomass-coupled green hydrogen-to-green methanol system according to claim 1 is characterized in that: It also includes a biomass gasification product purification device (5) and a biomass gasification product separation device. The biomass gasification device (2), the biomass gasification product purification device (5), the biomass gasification product separation device and the methanol synthesis device are connected in sequence.

3. The biomass-coupled green hydrogen-to-green methanol system according to claim 2 is characterized in that: It also includes a carbon dioxide gas capture device (6) and a methane gas capture device. The biomass direct combustion device (3), the carbon dioxide gas capture device (6) and the methanol synthesis device are connected in sequence.

4. The biomass-coupled green hydrogen-to-green methanol system according to claim 3 is characterized in that: It also includes a methane reforming reactor, and the biomass gasification product separation device and the methane gas capture device are both connected to the methane reforming reactor.

5. The biomass-coupled green hydrogen-to-green methanol system according to claim 4 is characterized in that: The methanol synthesis device comprises a first booster pump (7), a first synthesis tower (8), a first gas-liquid separator (9), a second booster pump (10), a second synthesis tower (11) and a second gas-liquid separator (12). The biomass gasification product separation device, the first booster pump (7), the first synthesis tower (8) and the first gas-liquid separator (9) are connected in sequence; The carbon dioxide gas capture device (6), the second booster pump (10), the second synthesis tower (11) and the second gas-liquid separator (12) are connected in sequence; The hydrogen generated by the water electrolysis hydrogen production device (1) is in communication with the first booster pump (7) and the second booster pump (10); The first gas-liquid separator (9) and the second gas-liquid separator (12) are respectively connected to the first synthesis tower (8) and the second synthesis tower (11) in reverse direction; The methane reforming reactor is in communication with the first synthesis tower (8).

6. The biomass-coupled green hydrogen-to-green methanol system according to claim 5 is characterized in that: It also includes a methanol distillation device, and the first gas-liquid separator (9) and the second gas-liquid separator (12) are both connected to the methanol distillation device.

7. The biomass-coupled green hydrogen-to-green methanol system according to claim 1, characterized in that: It also comprises a wind-solar complementary power generation device, which supplies power to the water electrolysis hydrogen production device (1).

8. A method for producing green methanol using the biomass-coupled green hydrogen-to-green methanol system according to claims 1-7, characterized in that: The following steps are involved: Producing hydrogen and oxygen by means of a water electrolysis hydrogen production device (1); The oxygen produced by the water electrolysis hydrogen production device (1) is transported to the biomass gasification device (2) as the raw gas for biomass gasification. The gasification gas produced by the biomass gasification is purified and separated to obtain carbon monoxide and hydrogen produced by the water electrolysis hydrogen production device (1) and transported to the first synthesis tower (8) to obtain crude methanol. The carbon dioxide produced by direct combustion of biomass and the hydrogen produced by the water electrolysis hydrogen production device (1) are transported to the second synthesis tower (11) to obtain crude methanol; The methane gas obtained by purifying and separating the gasification gas produced by biomass gasification, the methane gas produced by direct combustion of biomass and water are transported to a methane reforming reactor, and the generated carbon monoxide and hydrogen are transported to a first synthesis tower (8); The crude methanol produced by the first synthesis tower (8) and the second synthesis tower (11) is transported to a methanol distillation device, and is distilled to obtain dark green biomethanol.

9. The method for producing green methanol according to claim 8, characterized in that: In the methane reforming reactor, the reaction temperature is 600-800° C., the reaction pressure is 2-5 MPa, and the catalyst is any one of nickel, rhodium, platinum and palladium or its oxide.

10. The method for producing green methanol according to claim 9, characterized in that: In the first synthesis tower (8), the reaction temperature is 200-300°C, the reaction pressure is 1-10MPa, and the catalyst is an oxide of any one of copper, zinc and chromium; In the second synthesis tower (11), the reaction temperature is 200-300°C, the reaction pressure is 20-100 MPa, and the catalyst is an oxide of any one of copper, zinc and chromium.

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