Production method and production system of green methanol

Abstract

The invention discloses a production method and a production system of green methanol, and the production method comprises the following steps: mixing charcoal and pulverized coal with oxygen, and carrying out gasification reaction to obtain crude synthesis gas; cooling and purifying the crude synthesis gas, and then carrying out water-gas shift reaction to adjust the hydrogen-carbon ratio, so as to obtain converted crude synthesis gas; carrying out deacidification treatment on the converted crude synthesis gas to separate out an acidic compound so as to obtain purified synthesis gas; and carrying out synthesis treatment on the purified synthesis gas to obtain green methanol. According to the method, the green methanol can be efficiently prepared through biomass gasification and hydrogenation, meanwhile, a blending system is arranged to guarantee the reliability of green methanol production, the yield and conversion rate of the green methanol can be increased, resource utilization of biomass is achieved, meanwhile, the method has important application prospects in the aspects of reducing fossil fuel dependence and reducing carbon emission, and the method is worthy of popularization and application. The method is of great significance in improving the ecological environment, establishing a sustainable energy system and promoting economic and social development.

Description

Technical Field

[0001] The present invention relates to the technical field of green methanol synthesis, and more specifically, to a green methanol production method and a production system thereof. Background Art

[0002] With the growth of global demand for clean energy, methanol has attracted widespread attention as a high calorific value, easy to store and transport and important low-carbon clean energy. Traditional methanol production generally adopts water-coal slurry and pulverized coal gasification routes. The carbon emissions generated in the methanol production process are large, which is not conducive to the protection of the ecological environment.

[0003] Therefore, how to achieve carbon dioxide emission reduction in the coal-to-methanol process and increase green methanol production capacity without increasing coal consumption has become an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and provide a green methanol production method and a production system based on biomass resource utilization, which can utilize biomass gasification and hydrogenation to efficiently prepare green methanol. At the same time, a blending system is set up to ensure the reliability of green methanol production, which can increase the output and conversion rate of green methanol, reduce the production cost of green methanol, and realize the resource utilization of biomass. It has important application prospects in reducing dependence on fossil fuels and reducing carbon emissions, and will be of great significance to improving the ecological environment, establishing a sustainable energy system, and promoting economic and social development.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A method for producing green methanol comprises the following steps:

[0007] (1) mixing biochar and pulverized coal with oxygen and performing a gasification reaction to obtain a crude synthesis gas; wherein the mass ratio of the biochar to the pulverized coal is (0-1):(0-1);

[0008] (2) cooling and purifying the crude synthesis gas to remove ash and carbon black impurities, and then subjecting the crude synthesis gas after cooling and purification to a water-gas shift reaction under the action of a Ni-based catalyst to adjust the hydrogen-to-carbon ratio to 2.05 to 3.10, thereby obtaining a shifted crude synthesis gas;

[0009] (3) subjecting the converted crude synthesis gas to a deacidification treatment to separate acidic compounds and obtain purified synthesis gas;

[0010] (4) The purified synthesis gas is synthesized under the action of a Cu-Zn-Al based catalyst to obtain green methanol.

[0011] Optionally, in step (1), the crude synthesis gas includes one or more of CO, CO2, H2 and CH4.

[0012] Optionally, in step (1), the source of the biochar includes one or more of rice husks, wood chips, straw and other agricultural and forestry wastes.

[0013] Optionally, in step (1), the gasification pressure of the gasification reaction is 1.0 MPa to 9.0 MPa, and the gasification temperature is 800° C. to 1800° C.

[0014] Optionally, in step (1), the particle size of the biochar is less than 100 μm; and the particle size of the pulverized coal is less than 100 μm.

[0015] Optionally, in step (2), the pressure of the water-gas shift reaction is 2MPa-3MPa, and the temperature is 180°C-350°C.

[0016] Optionally, in step (3), the removal agent used in the deacidification treatment is methanol.

[0017] Optionally, in step (4), the synthesis treatment is carried out at a pressure of 2.5 MPa to 5 MPa, a temperature of 200° C. to 300° C., a space velocity of 3000 ml / (g cat·h) to 10000 ml / (g cat·h), and a methanol selectivity of >80%.

[0018] The present invention also discloses a green methanol production system, and the production system realizes the production method as described above;

[0019] The production system includes a gasification device, a purification and cooling device, a water-gas shift device, an acid gas separation device, a methanol synthesis device and a methanol purification device;

[0020] The gasification device is used to mix biochar and / or pulverized coal with oxygen and perform a gasification reaction to generate a crude synthesis gas;

[0021] The purification and cooling device is in communication with the crude synthesis gas outlet of the gasification device and is used for cooling and purifying the crude synthesis gas;

[0022] The water-gas shift device is connected to the purification device and is used to perform a water-gas shift reaction on the raw synthesis gas after cooling and purification to adjust the hydrogen-carbon ratio;

[0023] The acid gas separation device is connected to the water-gas shift device and is used to separate the raw synthesis gas after the shift to separate the acidic compounds and obtain the purified synthesis gas;

[0024] The acid gas separation device has a synthesis gas outlet for discharging clean synthesis gas and an acid compound outlet for discharging acid compounds;

[0025] The methanol synthesis device is in communication with the synthesis gas outlet and is used for performing synthesis treatment on the clean synthesis gas to obtain crude methanol;

[0026] The methanol synthesis device has a discharge port for discharging crude methanol, and the discharge port is connected to the gas inlet of the methanol purification device and is used for purifying the crude methanol to obtain green methanol.

[0027] Optionally, the water-gas shift device is connected to the purification device, and the step of subjecting the crude synthesis gas after cooling and purification to water-gas shift reaction includes: the water-gas shift device has a hydrogen inlet for adding hydrogen to the crude synthesis gas after cooling and purification, and the crude synthesis gas after cooling and purification undergoes water-gas shift reaction under the action of a Ni-based catalyst to adjust the hydrogen-carbon ratio to 2.05-3.10.

[0028] Optionally, the system further comprises an air separation device, wherein an oxygen outlet of the air separation device is connected to the gasification device to provide oxygen to the gasification device.

[0029] Optionally, the methanol synthesis unit is connected to the synthesis gas outlet, and the step of synthesizing the clean synthesis gas to obtain crude methanol includes: passing the clean synthesis gas into the methanol synthesis unit, wherein the methanol synthesis unit has a Cu-Zn-Al-based catalyst, and the methanol synthesis unit synthesizes the clean synthesis gas under the action of the catalyst.

[0030] Optionally, the carbon emission intensity of the production system is 3g CO2eq / MJ to 300g CO2eq / MJ.

[0031] Optionally, the production system includes coupled green hydrogen and green electricity and / or uncoupled green hydrogen and green electricity.

[0032] Optionally, the biochar and pulverized coal enter the gasification device via CO2 carrier gas.

[0033] Implementing the embodiments of the present invention will have the following beneficial effects:

[0034] The present invention discloses a production method and a production system of green methanol based on biomass resource utilization, wherein biochar replaces part of pulverized coal, cools and purifies raw coal gas produced by a gasification device through a purification and cooling device, cools and purifies synthesis gas treated by a water-gas shift device through an acid gas separation device to separate carbon dioxide, synthesis gas and sulfide; and synthesizes the separated synthesis gas through a methanol synthesis device to obtain green methanol, thereby achieving carbon dioxide emission reduction while improving the utilization efficiency of carbon in coal, effectively converting biochar into low-carbon methanol fuel in an efficient, stable and economical manner, increasing methanol production capacity without increasing coal consumption, and combining the process with green energy production to bring considerable economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a flow chart of a green methanol production system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited in any way.

[0037] The present invention discloses a method for producing green methanol, comprising the following steps:

[0038] (1) Biochar and pulverized coal are mixed with oxygen and then subjected to gasification reaction to obtain a crude synthesis gas; wherein the mass ratio of the biochar to the pulverized coal is (0-1):(0-1).

[0039] In a specific embodiment, the mass ratio of biochar to pulverized coal is preferably 1:1.

[0040] In a specific embodiment, the raw synthesis gas includes one or more of CO, CO2, H2 and CH4.

[0041] In a specific embodiment, the source of biochar includes one or more of rice husks, wood chips, straw and other agricultural and forestry wastes.

[0042] In a specific embodiment, the gasification pressure of the gasification reaction is 1.0 MPa to 9.0 MPa, and the gasification temperature is 800° C. to 1800° C.

[0043] In a specific embodiment, the preparation method of biochar includes: crushing agricultural and forestry waste into particles of 3mm to 5mm, heating and drying to make the moisture content reach 10-20%, thermally cracking at a heating rate of 25°C / min and isolated from air at 400°C to obtain biochar and cracking liquid, and the cracking gas obtained by thermal cracking replenishes the electricity consumption of biomass thermal cracking; grinding the obtained biochar in a ball mill, the speed of the ball mill is 300r / min, the grinding time is 30min, and screening to obtain biochar with a particle size of less than 100μm.

[0044] In a specific embodiment, the preparation method of pulverized coal includes: grinding the coal in a ball mill at a rotation speed of 300 r / min for 30 min, and sieving to obtain coal powder with a particle size of less than 100 μm.

[0045] (2) The crude synthesis gas is cooled and purified to remove ash and carbon black impurities, and then the crude synthesis gas after cooling and purification is subjected to a water-gas shift reaction under the action of a Ni-based catalyst to adjust the hydrogen-carbon ratio to 2.05-3.10 to obtain a converted crude synthesis gas.

[0046] In a specific embodiment, the pressure of the water-gas shift reaction is 2MPa-3MPa, and the temperature is 180°C-350°C.

[0047] (3) The converted raw synthesis gas is subjected to deacidification treatment to separate acidic compounds and obtain purified synthesis gas.

[0048] In a specific embodiment, the removal agent used in the deacidification treatment is methanol.

[0049] (4) The purified synthesis gas is synthesized under the action of a Cu-Zn-Al based catalyst to obtain green methanol.

[0050] In a specific embodiment, the synthesis treatment pressure is 2.5MPa-5MPa, the temperature is 200°C-300°C, the space velocity is maintained at 3000ml / (g cat·h)-10000ml / (g cat·h), and the methanol selectivity is >80%.

[0051] The present invention also discloses a green methanol production system, such as Figure 1 As shown, Figure 1 This is a flow chart of a green methanol production system according to an embodiment of the present invention. The production system implements a production method according to any embodiment of the present invention. The production system includes a gasification device, a purification and cooling device, a water-gas shift device, an acid gas separation device, a methanol synthesis device, and a methanol purification device.

[0052] In a specific embodiment, the system further comprises an air separation device, and an oxygen outlet of the air separation device is connected to the gasification device to provide oxygen to the gasification device.

[0053] Furthermore, the gasification device is used to mix the biochar and / or pulverized coal with oxygen and perform a gasification reaction to generate a raw synthesis gas.

[0054] Furthermore, the purification and cooling device is connected to the crude synthesis gas outlet of the gasification device, and is used for cooling and purifying the crude synthesis gas.

[0055] Furthermore, the water-gas shift device is connected to the purification device and is used to subject the raw synthesis gas after cooling and purification to a water-gas shift reaction to adjust the hydrogen-carbon ratio.

[0056] In a specific embodiment, the water-gas shift device is connected to the purification device, and the steps for subjecting the crude synthesis gas after cooling and purification to water-gas shift reaction include: the water-gas shift device has a hydrogen inlet for adding hydrogen to the crude synthesis gas after cooling and purification, and the crude synthesis gas after cooling and purification undergoes water-gas shift reaction under the action of a Ni-based catalyst to adjust the hydrogen-carbon ratio to 2.05-3.10.

[0057] Specifically, the reaction formula for preparing the transformed crude synthesis gas by water gas reaction using the crude synthesis gas after cooling and purification as a raw material is shown in (I):

[0058] CO+H2O→CO2+H2 (Ⅰ)

[0059] Furthermore, the acid gas separation device is connected to the water-gas shift device and is used to separate the raw synthesis gas after the shift to separate the acidic compounds and obtain the purified synthesis gas;

[0060] The acid gas separation device has a synthesis gas outlet for discharging the net synthesis gas and an acid compound outlet for discharging the acid compound;

[0061] Furthermore, the methanol synthesis device is connected to the synthesis gas outlet and is used to perform synthesis treatment on the clean synthesis gas to obtain crude methanol.

[0062] In a specific embodiment, the methanol synthesis unit is connected to the synthesis gas outlet, and the step of synthesizing the clean synthesis gas to obtain crude methanol includes: introducing the clean synthesis gas into the methanol synthesis unit, wherein the methanol synthesis unit has a Cu-Zn-Al-based catalyst, and the methanol synthesis unit synthesizes the clean synthesis gas under the action of the catalyst.

[0063] In a specific embodiment, the reaction formula for preparing methanol using CO and H2 as raw materials is shown in (II):

[0064] CO+2H2→CH3OH (Ⅱ)

[0065] Furthermore, the methanol synthesis device has a discharge port for discharging crude methanol, and the discharge port is connected to the gas inlet of the methanol purification device for purifying the crude methanol to obtain green methanol.

[0066] In a specific embodiment, the carbon emission intensity of the production system is 3g CO2eq / MJ to 300g CO2eq / MJ.

[0067] In a specific embodiment, the production system includes coupling of green hydrogen and green electricity and / or non-coupling of green hydrogen and green electricity.

[0068] In a specific embodiment, biochar and pulverized coal enter the gasification device through CO2 carrier gas.

[0069] The following are specific embodiments

[0070] Example 1

[0071] Use Figure 1 The green methanol production system shown in the figure, the green methanol production method of this embodiment, comprises the following steps:

[0072] (1) The corn stalks are crushed into particles of 3 mm to 5 mm, and heated and dried to make the moisture content reach 10 to 20%, and thermally cracked at a heating rate of 25° C. / min and 400° C. in an airtight state to obtain biochar and cracking liquid, and the cracking gas obtained by thermal cracking is used to supplement the power consumption of biomass thermal cracking; the biochar produced by thermal cracking in this embodiment has a Hardgrove grindability index of 124, a dry ash-free volatile matter of 36.45%, and a charcoal yield of 41.65%.

[0073] (2) The obtained biochar was ground in a ball mill at a speed of 300 r / min for 30 min, and the biochar with a particle size of less than 100 μm was sieved.

[0074] (3) The biochar is introduced into a gasification device through a CO2 carrier gas and mixed with the oxygen generated by the air separation device, and a gasification reaction is carried out at 1400°C and 4.2MPa to obtain a crude synthesis gas; the crude synthesis gas includes two or more of CO, CO2, H2 and CH4.

[0075] (4) The crude synthesis gas is passed into a purification cooling device for cooling to remove ash and carbon black impurities, thereby obtaining a crude synthesis gas that has been cooled and purified.

[0076] (5) The crude synthesis gas after cooling and purification is introduced into a water-gas shift device, hydrogen is added to the crude synthesis gas after cooling and purification through a hydrogen inlet, and a water-gas shift reaction is carried out under the action of a Ni-based catalyst. The pressure of the water-gas shift reaction is 2 MPa and the temperature is 250°C to adjust the hydrogen-carbon ratio to 2.05-3.10:1, thereby obtaining the converted crude synthesis gas.

[0077] Specifically, the reaction formula for preparing the transformed crude synthesis gas by water gas reaction using the crude synthesis gas after cooling and purification as a raw material is shown in (I):

[0078] CO+H2O→CO2+H2 (Ⅰ)

[0079] (6) The converted raw synthesis gas is passed into an acid gas separation device to remove sulfide and CO2 using methanol to obtain purified synthesis gas.

[0080] (7) The purified synthesis gas is introduced into a methanol synthesis device to synthesize methanol under the action of a Cu-Zn-Al based catalyst. The synthesis process is carried out at a pressure of 3 MPa, a temperature of 250° C., and a space velocity of 8000 ml / (g cat·h). The gas is purified by a methanol purification device to obtain green methanol.

[0081] Specifically, the reaction formula for preparing methanol using CO and H2 as raw materials is shown in (II):

[0082] CO+2H2→CH3OH (Ⅱ)

[0083] The process uses green electricity and green hydrogen, with a carbon emission intensity of 5 to 10g CO2 / MJ.

[0084] Example 2

[0085] Use Figure 1 The green methanol production system shown in the figure, the green methanol production method of this embodiment, comprises the following steps:

[0086] (1) The coal was ground in a ball mill at a speed of 300 r / min for 30 min, and pulverized coal with a particle size of less than 100 μm was obtained by screening.

[0087] (2) Pulverized coal is introduced into a gasification device through a CO2 carrier gas and mixed with oxygen generated by an air separation device, and a gasification reaction is carried out at 1400°C and 4.2MPa to obtain a crude synthesis gas; the crude synthesis gas includes two or more of CO, CO2, H2 and CH4.

[0088] (3) The crude synthesis gas is passed into a purification cooling device for cooling to remove ash and carbon black impurities, thereby obtaining a crude synthesis gas that has been cooled and purified.

[0089] (4) The crude synthesis gas after cooling and purification is introduced into a water-gas shift device, hydrogen is added to the crude synthesis gas after cooling and purification through a hydrogen inlet, and a water-gas shift reaction is carried out under the action of a Ni-based catalyst. The pressure of the water-gas shift reaction is 2 MPa and the temperature is 250°C to adjust the hydrogen-carbon ratio to 2.05-3.10:1 to obtain the converted crude synthesis gas.

[0090] Specifically, the reaction formula for preparing the transformed crude synthesis gas by water gas reaction using the crude synthesis gas after cooling and purification as a raw material is shown in (I):

[0091] CO+H2O→CO2+H2 (Ⅰ)

[0092] (5) The converted raw synthesis gas is passed into an acid gas separation device to remove sulfide and CO2 using methanol to obtain purified synthesis gas.

[0093] (6) The purified synthesis gas is introduced into a methanol synthesis device to synthesize methanol under the action of a Cu-Zn-Al based catalyst. The synthesis process is carried out at a pressure of 3 MPa, a temperature of 250° C., and a space velocity of 8000 ml / (g cat·h). The gas is purified by a methanol purification device to obtain green methanol.

[0094] Specifically, the reaction formula for preparing methanol using CO and H2 as raw materials is shown in (II):

[0095] CO+2H2→CH3OH (Ⅱ)

[0096] The process uses uncoupled green hydrogen and green electricity, and its carbon emission intensity is 300g CO2 / MJ.

[0097] Example 3

[0098] Use Figure 1 The green methanol production system shown in the figure, the green methanol production method of this embodiment, comprises the following steps:

[0099] (1) The corn stalks are crushed into particles of 3 mm to 5 mm, and heated and dried to make the moisture content reach 10 to 20%, and thermally cracked at a heating rate of 25° C. / min and 400° C. in an airtight state to obtain biochar and cracking liquid, and the cracking gas obtained by thermal cracking is used to supplement the power consumption of biomass thermal cracking; the biochar produced by thermal cracking in this embodiment has a Hardgrove grindability index of 124, a dry ash-free volatile matter of 36.45%, and a charcoal yield of 41.65%.

[0100] (2) Grinding the coal and the biochar obtained in step (1) in a ball mill respectively at a rotation speed of 300 r / min for 30 min, screening to obtain biochar and coal with a particle size of less than 100 μm, and then mixing the ground biochar and pulverized coal in a ratio of 1:1 to obtain mixed particles.

[0101] (3) The mixed particles are introduced into a gasification device through a CO2 carrier gas and mixed with oxygen generated by an air separation device, and a gasification reaction is carried out at 1400°C and 4.2MPa to obtain a crude synthesis gas; the crude synthesis gas includes two or more of CO, CO2, H2 and CH4.

[0102] (4) The crude synthesis gas is passed into a purification cooling device for cooling to remove ash and carbon black impurities, thereby obtaining a crude synthesis gas that has been cooled and purified.

[0103] (5) The crude synthesis gas after cooling and purification is introduced into a water-gas shift device, hydrogen is added to the crude synthesis gas after cooling and purification through a hydrogen inlet, and a water-gas shift reaction is carried out under the action of a Ni-based catalyst. The pressure of the water-gas shift reaction is 2 MPa and the temperature is 250°C to adjust the hydrogen-carbon ratio to 2.05-3.10:1, thereby obtaining the converted crude synthesis gas.

[0104] Specifically, the reaction formula for preparing the transformed crude synthesis gas by water gas reaction using the crude synthesis gas after cooling and purification as a raw material is shown in (I):

[0105] CO+H2O→CO2+H2 (Ⅰ)

[0106] (6) The converted raw synthesis gas is passed into an acid gas separation device to remove sulfide and CO2 using methanol to obtain purified synthesis gas.

[0107] (7) The purified synthesis gas is introduced into a methanol synthesis device to synthesize methanol under the action of a Cu-Zn-Al based catalyst. The synthesis process is carried out at a pressure of 3 MPa, a temperature of 250° C., and a space velocity of 8000 ml / (g cat·h). The gas is purified by a methanol purification device to obtain green methanol.

[0108] Specifically, the reaction formula for preparing methanol using CO and H2 as raw materials is shown in (II):

[0109] CO+2H2→CH3OH (Ⅱ)

[0110] The process uses green electricity and green hydrogen, with a carbon emission intensity of 102.5g CO2 / MJ.

[0111] In summary, the present invention discloses a green methanol production method based on biomass resource utilization and a production system thereof, which replaces part of pulverized coal with biochar, and reasonably selects the mixing ratio of biochar and pulverized coal through multiple experiments, and can utilize biomass gasification and hydrogenation to efficiently prepare green methanol. At the same time, a blending system is set up to ensure the reliability of green methanol production, which can increase the output and conversion rate of green methanol and reduce the production cost of green methanol. While realizing the resource utilization of biomass, it has important application prospects in reducing dependence on fossil fuels and reducing carbon emissions.

[0112] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for producing green methanol, characterized in that: The following steps are involved: (1) mixing biochar and pulverized coal with oxygen and performing a gasification reaction to obtain a crude synthesis gas; wherein the mass ratio of the biochar to the pulverized coal is (0-1):(0-1); (2) cooling and purifying the crude synthesis gas to remove ash and carbon black impurities, and then subjecting the crude synthesis gas after cooling and purification to a water-gas shift reaction under the action of a Ni-based catalyst to adjust the hydrogen-to-carbon ratio to 2.05 to 3.10, thereby obtaining a shifted crude synthesis gas; (3) subjecting the converted crude synthesis gas to a deacidification treatment to separate acidic compounds and obtain purified synthesis gas; (4) The purified synthesis gas is synthesized under the action of a Cu-Zn-Al based catalyst to obtain green methanol.

2. The method for producing green methanol according to claim 1, characterized in that: In step (1), the crude synthesis gas includes one or more of CO, CO2, H2 and CH4; The source of the biochar includes one or more of rice husks, wood chips, straw and other agricultural and forestry wastes; The gasification reaction has a gasification pressure of 1.0 MPa to 9.0 MPa and a gasification temperature of 800° C. to 1800° C.; The particle size of the biochar is less than 100 μm; The particle size of the pulverized coal is less than 100 μm.

3. The method for producing green methanol according to claim 1, characterized in that: In step (2), the pressure of the water-gas shift reaction is 2MPa-3MPa, and the temperature is 180°C-350°C.

4. The method for producing green methanol according to claim 1, characterized in that: In step (3), the removal agent used in the deacidification treatment is methanol.

5. The method for producing green methanol according to claim 1, characterized in that: In step (4), the synthesis treatment is carried out under a pressure of 2.5 MPa to 5 MPa, at a temperature of 200° C. to 300° C., with a space velocity of 3000 ml / (g cat·h) to 10000 ml / (g cat·h), and a methanol selectivity of >80%.

6. A green methanol production system, characterized in that: The production system implements the production method according to any one of claims 1 to 5; The production system includes a gasification device, a purification and cooling device, a water-gas shift device, an acid gas separation device, a methanol synthesis device and a methanol purification device; The gasification device is used to mix biochar and / or pulverized coal with oxygen and perform a gasification reaction to generate a crude synthesis gas; The purification and cooling device is in communication with the crude synthesis gas outlet of the gasification device and is used for cooling and purifying the crude synthesis gas; The water-gas shift device is connected to the purification device and is used to perform a water-gas shift reaction on the raw synthesis gas after cooling and purification to adjust the hydrogen-carbon ratio; The acid gas separation device is connected to the water-gas shift device and is used to separate the raw synthesis gas after the shift to separate the acidic compounds and obtain the purified synthesis gas; The acid gas separation device has a synthesis gas outlet for discharging clean synthesis gas and an acid compound outlet for discharging acid compounds; The methanol synthesis device is in communication with the synthesis gas outlet and is used for performing synthesis treatment on the clean synthesis gas to obtain crude methanol; The methanol synthesis device has a discharge port for discharging crude methanol, and the discharge port is connected to the gas inlet of the methanol purification device and is used for purifying the crude methanol to obtain green methanol.

7. The green methanol production system according to claim 6, characterized in that: The water-gas shift device is connected to the purification device, and the steps for subjecting the raw synthesis gas after cooling and purification to water-gas shift reaction include: The water-gas shift device has a hydrogen inlet for adding hydrogen to the crude synthesis gas after cooling and purification. The crude synthesis gas after cooling and purification undergoes a water-gas shift reaction under the action of a Ni-based catalyst to adjust the hydrogen-carbon ratio to 2.05-3.

10.

8. The green methanol production system according to claim 6, characterized in that: The system further comprises an air separation device, wherein an oxygen outlet of the air separation device is in communication with the gasification device to provide oxygen to the gasification device.

9. The green methanol production system according to claim 6, characterized in that: The methanol synthesis device is in communication with the synthesis gas outlet and is used to perform synthesis treatment on the clean synthesis gas to obtain crude methanol, the steps comprising: The clean synthesis gas is introduced into a methanol synthesis device, wherein the methanol synthesis device has a Cu-Zn-Al-based catalyst, and the methanol synthesis device performs synthesis treatment on the clean synthesis gas under the action of the catalyst.

10. The green methanol production system according to claim 6, characterized in that: The carbon emission intensity of the production system is 3g CO2eq / MJ to 300g CO2eq / MJ; The production system includes coupling green hydrogen and green electricity and / or non-coupling green hydrogen and green electricity; The biochar and pulverized coal enter the gasification device through CO2 carrier gas.

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