Method for capturing carbon dioxide to participate in biomass gasification to prepare green methanol

Abstract

The invention discloses a method for capturing carbon dioxide to participate in biomass gasification to prepare green methanol, and particularly relates to the field of biomass energy utilization, a gasification furnace body, a dust removal heat exchanger and a purification water washing box are included, and the exhaust end of the purification water washing box is connected with a high-voltage electrostatic decoking device through a pipeline; the exhaust end of the high-voltage electrostatic decoking device is connected with a synthetic gas cabinet, the synthetic gas cabinet is connected with a gas desulfurization and dechlorination purifier through a pipeline, and the exhaust end of the gas desulfurization and dechlorination purifier is connected with an effective gas reforming transformation box through a pipeline; and the effective gas reforming transformation box is connected with a gasifying agent inlet at the bottom end of the gasifier body through a pipeline. Carbon dioxide discharged in the secondary reforming transformation process of gasified synthesis gas is captured and fed into the gasifying agent at the front end, the carbon dioxide is doped into the gasifying agent, so that the oxygen proportion is reduced, a small amount of oxygen can promote pyrolysis and gasification reaction of biomass, the yield of hydrogen is increased, and waste gas utilization of the carbon dioxide is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass energy utilization, and more specifically, to a method for capturing carbon dioxide and participating in biomass gasification to produce green methanol. 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 the existing biomass gasifier is used, whether it is air as a gasifier, pure oxygen as a gasifier, or other mixed gases with oxygen as a gasifier, the biomass gasification synthesis gas produced is more carbon and less hydrogen. Since the carbon-hydrogen ratio required for the production of green methanol is 1:2, it is necessary to reform the biomass synthesis gas to increase the proportion of hydrogen, and carbon dioxide will be discharged during the reforming transformation process. The direct discharge of the discharged carbon dioxide is likely to cause a greenhouse effect and waste resources. The presence of more oxygen in the gasifier will not only lead to increased corrosion of the equipment and shorten the service life of the equipment, but also form an explosive mixture under certain conditions, increasing the risk of deflagration. Oxygen can partially oxidize with the carbon in the biomass to produce carbon monoxide and hydrogen. However, too much oxygen will cause the pyrolysis gasification process to be biased towards combustion reaction, resulting in an intensified combustion reaction, resulting in a decrease in the proportion of combustible components (such as hydrogen, carbon monoxide, etc.) in the synthesis gas, and reducing the calorific value and quality of the synthesis gas. 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 capturing carbon dioxide and participating in biomass gasification to produce green methanol.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a method for capturing carbon dioxide and participating in biomass gasification to produce green methanol, comprising a gasifier body, the exhaust end of the gasifier body is connected to the air inlet end of a dust removal heat exchanger through a pipeline, the exhaust end of the dust removal heat exchanger is connected to a purification water washing box through a pipeline, the exhaust end of the purification water washing box is connected to a high-voltage electrostatic decoker through a pipeline, the exhaust end of the high-voltage electrostatic decoker is connected to a synthesis gas cabinet, the exhaust end of the synthesis gas cabinet is connected to a gas desulfurization and dechlorination purifier through a pipeline, the exhaust end of the gas desulfurization and dechlorination purifier is connected to an effective gas reforming conversion box through a pipeline, the output end of the effective gas reforming conversion box is respectively connected to a carbon monoxide gas storage box and a hydrogen gas storage box through pipelines, the exhaust ends of the carbon monoxide gas storage box and the hydrogen gas storage box are both connected to a synthesis reactor, and the bottom end of the effective gas reforming conversion box is connected to the gasifying agent inlet at the bottom end of the gasifier body through a pipeline.

[0007] In a preferred embodiment, the heat exchanged by the dust removal heat exchanger is discharged into the insulation jacket on the outside of the effective gas reforming conversion box through a pipe. The dust removal heat exchanger is used to remove dust from the flue gas discharged from the gasification furnace body, and the heat after heat exchange is transferred to the gas distribution box to preheat the gas, which can save resources.

[0008] In a preferred embodiment, the mass ratio of carbon to hydrogen in the effective gas reforming conversion box is maintained at 1:2.

[0009] In a preferred embodiment, air and water vapor are also added at the gasifying agent inlet, and the volume ratio of the air to the water vapor is 3:1.

[0010] Compared with the prior art, the technical effects and advantages of the present invention are as follows:

[0011] 1. The present invention captures the carbon dioxide discharged during the secondary reforming conversion of gasified synthesis gas and feeds it into the gasifying agent at the front end. The addition of carbon dioxide into the gasifying agent reduces the proportion of oxygen. A small amount of oxygen can promote the pyrolysis and gasification reactions of biomass and increase the production of hydrogen. In addition, during the pyrolysis and gasification of biomass, an appropriate amount of carbon dioxide added to the gasifying agent can react with the carbon in the biomass to generate carbon monoxide. Carbon monoxide can further react with water vapor to produce hydrogen through a water-gas shift reaction (CO+H2O→CO2+H2). Therefore, under certain conditions, carbon dioxide can promote the production of hydrogen; it can realize the waste gas utilization of carbon dioxide, turning waste into treasure, and reducing the pollution of carbon dioxide emissions to the atmosphere;

[0012] 2. The present invention uses air and water vapor as gasifying agents and adds carbon dioxide, which can reduce the oxygen content. Too much oxygen will enhance the oxidizing atmosphere in the pyrolysis gasification system, which will easily lead to increased corrosion of equipment at high temperatures, shorten the service life of the equipment, and increase the equipment maintenance cost. Too much oxygen may cause the combustible gas in the pyrolysis gasification system to form an explosive mixture under certain conditions, increasing the risk of deflagration and posing a threat to the safety of operators and equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the system structure of Example 1 of the present invention.

[0014] In the figure: 1. Gasification furnace body; 2. Dust removal heat exchanger; 3. Purification water washing box; 4. High-voltage electrostatic decoking device; 5. Synthesis gas cabinet; 6. Gas desulfurization and dechlorination purifier; 7. Effective gas reforming conversion box; 8. Carbon monoxide storage box; 9. Hydrogen storage box; 10. Synthesis reactor. DETAILED DESCRIPTION

[0015] 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.

[0016] like Figure 1 As shown, a method for capturing carbon dioxide and participating in biomass gasification to produce green methanol comprises a gasifier body 1, the exhaust end of the gasifier body 1 is connected to the air inlet end of a dust removal heat exchanger 2 through a pipeline, the exhaust end of the dust removal heat exchanger 2 is connected to a purification water washing box 3 through a pipeline, the exhaust end of the purification water washing box 3 is connected to a high-voltage electrostatic coke remover 4 through a pipeline, the exhaust end of the high-voltage electrostatic coke remover 4 is connected to a synthesis gas cabinet 5, the exhaust end of the synthesis gas cabinet 5 is connected to a gas desulfurization and dechlorination purifier 6 through a pipeline, the exhaust end of the gas desulfurization and dechlorination purifier 6 is connected to an effective gas reforming conversion box 7 through a pipeline, the output end of the effective gas reforming conversion box 7 is respectively connected to a carbon monoxide gas storage box 8 and a hydrogen gas storage box 9 through pipelines, the exhaust ends of the carbon monoxide gas storage box 8 and the hydrogen gas storage box 9 are both connected to a synthesis reactor 10, and the bottom end of the effective gas reforming conversion box 7 is connected to the gasifying agent inlet at the bottom end of the gasifier body 1 through a pipeline.

[0017] In a preferred embodiment, the heat exchanged by the dust removal heat exchanger 2 is discharged into the insulation jacket outside the effective gas reforming conversion box 7 through a pipeline.

[0018] In a preferred embodiment, the mass ratio of carbon to hydrogen in the effective gas reforming conversion box 7 is maintained at 1:2.

[0019] In a preferred embodiment, air and water vapor are also added at the gasifying agent inlet, and the volume ratio of the air to the water vapor is 3:1.

[0020] Working principle of the present invention:

[0021] During use, the gasifier body 1 is used for reaction, and the gas discharged from the gasifier body 1 is introduced into the dust removal heat exchanger 2 for cooling. While cooling, the synthesis gas is filtered and dusted. The gas treated by the dust removal heat exchanger 2 is introduced into the purification water washing box 3. The purification water washing box 3 purifies and adsorbs the synthesis gas, so that the dust and tar content in the synthesis gas is low, and the tar in the synthesis gas is processed to less than 100 mg. The purified gas enters the high-voltage electrostatic decoking device 4 for decoking. The synthesis gas treated by the high-voltage electrostatic decoking device 4 can completely remove the tar. The decoked gas enters the synthesis gas cabinet 5. The main components in the synthesis gas cabinet 5 are carbon monoxide, hydrogen, methane, carbon dioxide and a very small amount of oxygen, and then passes through the gas desulfurization and dechlorination purifier. After purification, clean biosynthesis gas is obtained. The clean biosynthesis gas is reformed and transformed in the effective gas reforming conversion box 7 so that the mass ratio of carbon to hydrogen is 1:2. After the adjustment, the carbon monoxide and hydrogen are respectively introduced into the carbon monoxide gas storage box 8 and the hydrogen gas storage box 9. The carbon monoxide and hydrogen in the carbon monoxide gas storage box 8 and the hydrogen gas storage box 9 are used to synthesize green methanol in the synthesis reactor 10 under the action of a catalyst for energy substitution in industries such as shipping, thereby achieving the purpose of low-carbon emission reduction. The excess carbon dioxide in the effective gas reforming conversion box 7 is transported to the gasification agent addition port of the gasifier body 1 through a pipeline, and is added into the gasifier together with air and water vapor, so that the gasifier body 1 reacts, thereby achieving the reuse of carbon dioxide and reducing carbon dioxide emissions.

[0022] 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;

[0023] 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;

[0024] 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 capturing carbon dioxide and participating in biomass gasification to produce green methanol, comprising a gasifier body (1), characterized in that: The exhaust end of the gasifier body (1) is connected to the air inlet end of the dust removal heat exchanger (2) through a pipeline, the exhaust end of the dust removal heat exchanger (2) is connected to the purification water washing box (3) through a pipeline, the exhaust end of the purification water washing box (3) is connected to the high-voltage electrostatic decoker (4) through a pipeline, the exhaust end of the high-voltage electrostatic decoker (4) is connected to a synthesis gas cabinet (5), the exhaust end of the synthesis gas cabinet (5) is connected to a gas desulfurization and dechlorination purifier (6) through a pipeline, the exhaust end of the gas desulfurization and dechlorination purifier (6) is connected to an effective gas reforming conversion box (7) through a pipeline, the output end of the effective gas reforming conversion box (7) is respectively connected to a carbon monoxide gas storage box (8) and a hydrogen gas storage box (9) through pipelines, the exhaust ends of the carbon monoxide gas storage box (8) and the hydrogen gas storage box (9) are both connected to a synthesis reactor (10), and the bottom end of the effective gas reforming conversion box (7) is connected to the gasifying agent inlet at the bottom end of the gasifier body (1) through a pipeline.

2. The method for capturing carbon dioxide and participating in biomass gasification to produce green methanol according to claim 1, characterized in that: The heat exchanged by the dust removal heat exchanger (2) is discharged into the heat-insulating jacket outside the effective gas reforming conversion box (7) through a pipeline.

3. The method for capturing carbon dioxide and participating in biomass gasification to produce green methanol according to claim 1, characterized in that: The mass ratio of carbon to hydrogen in the effective gas reforming conversion box (7) is maintained at 1:

2.

4. The method for capturing carbon dioxide and participating in biomass gasification to produce green methanol according to claim 1, characterized in that: Air and water vapor are also added at the gasifying agent inlet, and the volume ratio of the air to the water vapor is 3:1.

Images