Method for producing green methanol by coupling carbon dioxide prepared by biomass gasification with green hydrogen

Abstract

The invention discloses a method for preparing carbon dioxide by biomass gasification and producing green methanol by coupling green hydrogen, which comprises a biomass gasifier, the exhaust end of the biomass gasifier is connected with a first group of dust removal heat exchangers through a pipeline, and the output end of a high-temperature fan is connected with a synthesis gas oxidation furnace; the output end of the synthesis gas oxidation furnace is connected with a second set of dust removal heat exchangers, the output end of the second set of dust removal heat exchangers is sequentially connected with a primary purification system and a secondary purification system through pipelines, and the output end of the secondary purification system is connected with a carbon dioxide storage cabinet through a Roots blower; the output end of the carbon dioxide storage cabinet is connected with the methanol synthesis reactor, and the input end of the methanol synthesis reactor is connected with the hydrogen discharge end of the electrolytic cell. The system is under normal pressure and local micro-negative pressure, so that the operation is simple and safe, the operation cost is low, the generation of green methanol is reduced on the whole, the adaptability to raw materials is high, the raw material standard requirement is low, and the cost of the raw materials can be greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass energy utilization, and more specifically, to a method for producing green methanol by coupling green hydrogen with biomass gasification to produce carbon dioxide. Background Art

[0002] Biomass energy is the fourth largest resource on earth, second only to coal, oil and natural gas, and is also the renewable energy with the largest reserves. Biomass has the characteristics of wide distribution, abundant reserves, renewability and low pollution, and is one of the most promising alternative energy sources to fossil energy. At present, the energy utilization of biomass energy is mainly based on fermentation to produce fuel, biogas, gasification, rapid pyrolysis and carbonization.

[0003] In the process of pyrolyzing biomass raw materials, the biomass gasification furnace initially uses high-temperature fuel gas with a furnace temperature of 700-800 degrees Celsius, and the fuel gas is mixed with tar (the tar is in gaseous form at this time). In order to effectively use this green fuel gas to replace fossil fuels, the high-temperature fuel gas needs to be cooled to room temperature before it can be transported to user equipment through pipelines.

[0004] When synthesizing green methanol from biomass gasification using biomass gasifiers, the biomass synthesis gas needs to be deeply processed. Since the biomass gasification synthesis gas in the prior art contains tar, it needs to be de-coked during the purification process. In addition, the boiling points of carbon monoxide and nitrogen are close, so separation is difficult and costly. Summary of the invention

[0005] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a method for producing green methanol by coupling green hydrogen with biomass gasification to produce carbon dioxide.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: A method for producing green methanol by coupling green hydrogen with biomass gasification to produce carbon dioxide, comprising a biomass gasifier, wherein the exhaust end of the biomass gasifier is connected to the air inlet end of a first group of dust removal heat exchangers through a pipeline, the exhaust end of the first group of dust removal heat exchangers is connected to the input end of a high-temperature fan through a pipeline, the output end of the high-temperature fan is connected to a synthesis gas oxidation furnace, the output end of the synthesis gas oxidation furnace is connected to a second group of dust removal heat exchangers, the output end of the second group of dust removal heat exchangers is connected to a primary purification system and a secondary purification system in sequence through a pipeline, the output end of the secondary purification system is connected to a carbon dioxide gas storage cabinet through a Roots blower, the output end of the carbon dioxide gas storage cabinet is a methanol synthesis reactor, the input end of the methanol synthesis reactor is connected to the hydrogen discharge end of an electrolyzer, and the oxygen discharge end of the electrolyzer is connected to an oxygen and carbon dioxide mixing tank.

[0007] In a preferred embodiment, the first group of dust removal heat exchangers and the second group of dust removal heat exchangers both use secondary cyclone dust collectors.

[0008] In a preferred embodiment, the waste heat of the first group of dust removal heat exchangers, the second group of dust removal heat exchangers and the synthesis gas oxidation furnace is recovered for heat, electricity and cooling supply.

[0009] In a preferred embodiment, the primary purification system is spray water washing dust removal, electrostatic dust removal or air cooling dust removal, and the secondary purification system is filter filtration and activated carbon adsorption.

[0010] In a preferred embodiment, the oxygen and carbon dioxide mixing tank is connected to a carbon dioxide gas storage cabinet, and the output end of the oxygen and carbon dioxide mixing tank is arranged at the gasification agent inlet of the biomass gasifier and the air inlet end of the synthesis gas oxidation furnace.

[0011] Compared with the prior art, the technical effects and advantages of the present invention are as follows:

[0012] 1. The present invention uses oxygen and carbon dioxide as gasifying agents instead of air as gasifying agent, which can make the nitrogen in the synthesis gas zero, avoiding the influence of nitrogen on the synthesis of green methanol in the later stage. At the same time, carbon dioxide as a gasifying agent reacts with the hot biochar at the bottom of the gasifier to increase the production of carbon monoxide, thereby increasing the total amount of effective carbon dioxide gas;

[0013] 2. The tar in the high-temperature synthesis gas from the biomass gasifier of the present invention is in gaseous state, and can be directly fully oxidized to decompose the tar into carbon dioxide and water, thereby increasing the total yield of effective carbon dioxide gas in the synthesis gas;

[0014] 3. The tar of the present invention is converted into carbon dioxide during the full oxidation process, which reduces the purification pressure of the subsequent synthesis gas and makes it easier to purify and obtain clean carbon dioxide effective gas;

[0015] 4. The waste heat generated in the full oxidation process of the biomass synthetic gas of the present invention can be recovered, and the waste heat of the first and second cyclone heat exchangers can also be recovered to provide cooling for the synthesis workshop of the project and heating and power supply for other workshops;

[0016] 5. The small amount of biochar produced during the gasification process of the biomass gasifier of the present invention can also be used as a filter agent in the filtering workshop;

[0017] 6. The entire gasification system of the present invention finally converts biomass into carbon dioxide, which is stored in a carbon dioxide gas storage cabinet. Since carbon dioxide is non-flammable and non-explosive, it is safer to store than carbon monoxide;

[0018] 7. The present invention directly performs oxygen-enriched combustion oxidation treatment on the synthesis gas generated by the biomass gasifier, stores the carbon dioxide generated by the combustion after purification, and then synthesizes green methanol with hydrogen and carbon dioxide generated by the electrolyzer. The equipment has low cost, is simple and easy to operate, is suitable for distributed application, is suitable for the dispersion of biomass raw materials, has strong adaptability to raw materials, has low raw material standard requirements, and can greatly reduce the cost of raw materials;

[0019] 8. The present invention uses the oxygen generated by the electrolytic cell and the carbon dioxide in the gas storage cabinet to mix as the gasification agent of the biomass gasifier, which is convenient for the quantitative ratio of oxidation and carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the system structure of Example 1 of the present invention.

[0021] In the figure: 1. Biomass gasification furnace; 2. The first set of dust removal heat exchangers; 3. High-temperature fan; 4. Syngas oxidation furnace; 5. The second set of dust removal heat exchangers; 6. Primary purification system; 7. Secondary purification system; 8. Roots blower; 9. Carbon dioxide gas storage cabinet; 10. Methanol synthesis reactor; 11. Electrolyzer; 12. Oxygen and carbon dioxide mixing tank. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not 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.

[0023] like Figure 1 As shown, a method for producing green methanol by coupling biomass gasification with carbon dioxide and green hydrogen comprises a biomass gasifier 1, wherein the exhaust end of the biomass gasifier 1 is connected to the air inlet end of a first group of dust removal heat exchangers 2 through a pipeline, the exhaust end of the first group of dust removal heat exchangers 2 is connected to the input end of a high-temperature fan 3 through a pipeline, the output end of the high-temperature fan 3 is connected to a synthesis gas oxidation furnace 4, the output end of the synthesis gas oxidation furnace 4 is connected to a second group of dust removal heat exchangers 5, the output end of the second group of dust removal heat exchangers 5 is connected to a primary purification system 6 and a secondary purification system 7 in sequence through a pipeline, the output end of the secondary purification system 7 is connected to a carbon dioxide gas storage cabinet 9 through a Roots blower 8, the output end of the carbon dioxide gas storage cabinet 9 is a methanol synthesis reactor 10, the input end of the methanol synthesis reactor 10 is connected to the hydrogen discharge end of an electrolyzer 11, and the oxygen discharge end of the electrolyzer 11 is connected to an oxygen and carbon dioxide mixing tank 12.

[0024] In a preferred embodiment, the first group of dust removal heat exchangers 2 and the second group of dust removal heat exchangers 5 both adopt two-stage cyclone dust collectors.

[0025] In a preferred embodiment, the waste heat recovery of the first group of dust removal heat exchangers 2, the second group of dust removal heat exchangers 5 and the synthesis gas oxidation furnace 4 is used for heat, electricity and cooling supply. The waste heat recovery can be used for cooling, heating and power generation, and the waste heat recovery can also directly cool the methanol synthesis reactor 10.

[0026] In a preferred embodiment, the primary purification system 6 is spray water washing dust removal, electrostatic dust removal or air cooling dust removal, and the secondary purification system 7 is filter filtration and activated carbon adsorption.

[0027] In a preferred embodiment, the oxygen and carbon dioxide mixing tank 12 is connected to the carbon dioxide gas storage cabinet 9, the output end of the oxygen and carbon dioxide mixing tank 12 is arranged at the gasification agent inlet of the biomass gasification furnace 1 and the air inlet end of the synthesis gas oxidation furnace 4, the input end of the oxygen and carbon dioxide mixing tank 12 is connected to the oxygen outlet of the electrolyzer and the carbon dioxide outlet of the carbon dioxide gas storage cabinet 9, and the carbon dioxide in the carbon dioxide gas storage cabinet 9 can be transported to the oxygen and carbon dioxide mixing tank 12 to form a gasification agent with the oxygen generated by the electrolyzer 11.

[0028] Working principle of the present invention:

[0029] When in use, the biomass is sent into the biomass gasification furnace 1 for pyrolysis and gasification, and the high-temperature synthesis gas generated by the pyrolysis and gasification is sent to the first group of dust removal and heat exchanger 2 for dust removal and cooling. The synthesizer after dust removal and cooling is sent to the synthesis gas oxidation furnace 4 by the high-temperature fan 3 for oxygen-enriched combustion treatment. The gas generated by the combustion of the synthesis gas oxidation furnace 4 is subjected to dust removal and cooling treatment by the second group of dust removal and heat exchanger 5 and then enters the primary purification system 6. The primary purification system performs preliminary treatments such as spray water washing, electrostatic dust removal, and air cooling dust removal on the gas. After the preliminary treatment is completed, it enters the secondary purification system 7 for filtration and activated carbon adsorption treatment. Then, the carbon dioxide obtained under the action of the Roots blower 8 is sent to the carbon dioxide gas storage cabinet 9, and the electrolyzer 11 is powered by green electricity. The hydrogen generated by electrolysis of the electrolyzer 11 The gas is input into the methanol synthesis reactor 10 to react with the carbon dioxide input into the carbon dioxide storage tank 9 for green methanol synthesis reaction, and the oxygen generated by electrolysis in the electrolyzer 11 is stored in the oxygen and carbon dioxide mixing tank 12, and the carbon dioxide in the carbon dioxide storage tank 9 supplies gas to the oxygen and carbon dioxide mixing tank 12, so that the ratio of carbon dioxide and oxygen in the oxygen and carbon dioxide mixing tank 12 is maintained within a certain range, and the mixed gas in the oxygen and carbon dioxide mixing tank 12 is used as a gasifying agent for the biomass gasification furnace 1, and the waste heat generated during the operation of the first group of dust removal heat exchangers 2, the synthesis gas oxidation furnace 4 and the second group of dust removal heat exchangers 5 is recovered and utilized, and the waste heat recovery can be used for cooling, heating and power generation, and the waste heat recovery can also directly cool the methanol synthesis reactor 10.

[0030] Finally, a few points should be explained: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, which may refer to mechanical connection or electrical connection, or internal communication between two components, or direct connection. "upper", "lower", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may change;

[0031] Secondly: In the drawings of the embodiments disclosed in the present invention, only the structures related to the embodiments disclosed in the present invention are involved, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0032] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for producing green methanol by coupling biomass gasification with carbon dioxide and green hydrogen, comprising a biomass gasifier (1), characterized in that: The exhaust end of the biomass gasifier (1) is connected to the air inlet end of the first group of dust removal heat exchangers (2) through a pipeline, the exhaust end of the first group of dust removal heat exchangers (2) is connected to the input end of a high-temperature fan (3) through a pipeline, the output end of the high-temperature fan (3) is connected to a synthesis gas oxidation furnace (4), the output end of the synthesis gas oxidation furnace (4) is connected to a second group of dust removal heat exchangers (5), the output end of the second group of dust removal heat exchangers (5) is connected to a primary purification system (6) and a secondary purification system (7) in sequence through a pipeline, the output end of the secondary purification system (7) is connected to a carbon dioxide gas storage cabinet (9) through a Roots blower (8), the output end of the carbon dioxide gas storage cabinet (9) is a methanol synthesis reactor (10), the input end of the methanol synthesis reactor (10) is connected to a hydrogen discharge end of an electrolyzer (11), and the oxygen discharge end of the electrolyzer (11) is connected to an oxygen and carbon dioxide mixing tank (12).

2. The method for producing green methanol by coupling green hydrogen with biomass gasification to produce carbon dioxide according to claim 1, characterized in that: The first group of dust removal heat exchangers (2) and the second group of dust removal heat exchangers (5) both use two-stage cyclone dust collectors.

3. The method for producing green methanol by coupling green hydrogen with biomass gasification to produce carbon dioxide according to claim 2, characterized in that: The waste heat from the first group of dust removal heat exchangers (2), the second group of dust removal heat exchangers (5) and the synthesis gas oxidation furnace (4) is recovered for heat, electricity and cooling supply.

4. The method for producing green methanol by coupling green hydrogen with biomass gasification to produce carbon dioxide according to claim 1, characterized in that: The primary purification system (6) is a spray water-washing dust removal, an electrostatic dust removal or an air-cooling dust removal, and the secondary purification system (7) is a filter filtration and activated carbon adsorption.

5. The method for producing green methanol by coupling green hydrogen with biomass gasification to produce carbon dioxide according to claim 1, characterized in that: The oxygen and carbon dioxide mixing tank (12) is connected to the carbon dioxide gas storage cabinet (9), and the output end of the oxygen and carbon dioxide mixing tank (12) is arranged at the gasification agent inlet of the biomass gasification furnace (1) and the air inlet end of the synthesis gas oxidation furnace (4).

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