System for preparing green methanol by coupling biomass gasification with green electricity electrolyzed water

Abstract

The utility model relates to a system for preparing green methanol by coupling biomass gasification with green electricity electrolyzed water, which comprises a biomass gasification reactor, a dust removal and recovery system, a cooling system, a washing tower, a gas filling device, a pressure control system, a methanol synthesis reactor, a condensation system, a rectification device and a methanol buffer tank which are connected in sequence, the biomass gasification reactor is respectively provided with a biomass feed port, an ash discharge port, a steam inlet and an oxygen inlet, and the bottom of the dust removal and recovery system is connected with the lower part of the biomass gasification reactor through a return pipeline; the electrolytic cell is connected with an oxygen inlet of the biomass gasification reactor through an oxygen conveying pipeline and connected with a gas filling device through a hydrogen conveying pipeline, and water vapor generated by the methanol synthesis reactor is connected to a vapor inlet of the biomass gasification reactor through a pipeline. According to the utility model, the pyrolysis gas does not need to be purified or shunted, the process flow is simplified, and the conversion per pass is improved.

Description

Technical Field

[0001] The utility model relates to a methanol preparation system, in particular to a system for preparing green methanol by coupling biomass gasification with green electricity electrolysis of water. Background Art

[0002] Combining renewable energy with electrochemistry, converting green electricity into chemical products, and converting electricity storage and transmission into chemical storage and transportation can greatly reduce the cost of electricity storage and transmission while expanding the space for green electricity consumption, creating favorable conditions for the development of high-quality renewable energy in remote areas. Compared with traditional energy storage methods such as pumped storage and electrochemical energy storage, hydrogen energy is a high-quality, clean, large-scale energy storage carrier, and methanol is considered an ideal hydrogen carrier. Using renewable green electricity to produce green methanol can save complex process links such as coal gasification and purification and reduce fixed asset investment. Water is directly electrolyzed into high-purity hydrogen and oxygen through green electricity. Hydrogen reacts with carbon monoxide and carbon dioxide formed from biomass combustion to produce green methanol in one step. The high-purity oxygen generated by electrolysis can be used for biomass gasification furnaces, greatly reducing the energy consumption of traditional air separation oxygen production; the generated green methanol product can be made into zero-carbon ocean shipping, or made into zero-carbon olefins, zero-carbon aromatics and other downstream chemicals; renewable green electricity to produce green hydrogen will greatly promote the zero-carbon transformation and upgrading of the chemical industry.

[0003] In the prior art, the system that uses the synthesis gas from biomass gasification to prepare green methanol needs to purify or divert the synthesis gas, and divert the carbon monoxide gas and carbon dioxide gas in the synthesis gas to prepare methanol, which increases the complexity of the process and increases the equipment investment cost. Utility Model Content

[0004] The utility model discloses a system for preparing green methanol by coupling biomass gasification with green electricity electrolysis of water. The system does not need to purify or divert the synthesis gas after biomass gasification, and can directly send it into a methanol synthesis reactor for preparing methanol, thereby reducing the complexity of the reaction process and lowering the equipment investment cost.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A system for preparing green methanol by coupling biomass gasification with green electricity electrolysis of water, comprising a biomass gasification device, an electrolysis of water device and a green methanol synthesis device; the biomass gasification device includes a biomass gasification reactor, a dust removal and recovery system, a cooling system and a scrubbing tower. The biomass gasification reactor is respectively provided with a biomass feeding port, a slag discharge port, a steam inlet, an oxygen inlet and a pyrolysis gas discharge port. The pyrolysis gas discharge port is connected to the dust removal and recovery system through a pipeline, the dust removal and recovery system is connected to the cooling system through a pipeline, the cooling system is connected to the scrubbing tower through a pipeline, and the bottom of the dust removal and recovery system is connected to the lower part of the biomass gasification reactor through a return pipeline;

[0007] The electrolysis of water device includes a solid polymer anion exchange membrane hydrogen production electrolyzer, and the electrolyzer is connected to the oxygen inlet of the biomass gasification reactor through an oxygen delivery pipeline;

[0008] The green methanol synthesis device includes a gas filling device, a pressure control system, a methanol synthesis reactor, a condensation system, a rectification device and a methanol buffer tank. The gas filling device includes a first compressor and a second compressor. The scrubbing tower transports pyrolysis gas to the first compressor through a pipeline, and the electrolyzer transports hydrogen to the second compressor through a hydrogen delivery pipeline. The compressed pyrolysis gas and hydrogen are transported to the methanol synthesis reactor through the pressure control system. The steam generated by the methanol synthesis reactor is connected to the steam inlet of the biomass gasification reactor through a pipeline. The methanol steam generated by the methanol synthesis reactor is transported to the condensation system. The condensation system is connected to the rectification device through a pipeline, and the rectification device is connected to the methanol buffer tank through a pipeline.

[0009] Furthermore, the electrolysis of water device further includes a hydrogen treatment and drying device, a water tank, a water treatment and purification system and an AC-DC converter.

[0010] Furthermore, the system for preparing green methanol by coupling biomass gasification with green electricity electrolysis of water further includes a pressure monitoring and control device, a temperature monitoring and control device, a feed rate control device and an intake air volume interlock control device.

[0011] Compared with the prior art, the utility model mainly has the following beneficial technical effects:

[0012] 1. By combining the gasification treatment of waste biomass with the methanol synthesis process, it avoids the nitrogen oxide impurities generated by the original treatment method of biomass waste or directly discharging flue gas into the atmosphere; all the carbon sources in the biomass are not discharged from the process flow of the present invention, making full use of the carbon source and having extremely high raw material utilization rate; the present invention does not require the purification or shunt treatment of CO2 and CO in the pyrolysis gas, but sends them into the methanol synthesis reactor for reaction together, which not only reduces the complexity of the reaction process flow and saves equipment costs, but more importantly, compared with the prior art of using pure rich CO2 to produce methanol after purification, it increases the proportion of CO in the raw material gas, so that the single-pass conversion rate of the process of the present invention can be increased by more than 60%.

[0013] 2. Adopting the power combination scheme of combining green electricity with electrolyzed water effectively overcomes the problem of the instability of new energy (wind energy, solar energy) power generation for producing green hydrogen due to weather, climate and other factors, improves the stability and reliability of the power consumption in the process flow, enables the process and system of the present invention to operate stably for a longer time, increases the output and thus improves the economic benefits.

[0014] 3. Inputting the by-product saturated steam in the methanol synthesis part into the biomass gasification process to promote the water-gas shift reaction and adjust the component ratio of the product gas, so that the obtained product gas not only meets the low tar content but also contains an appropriate amount of hydrogen; there is no need to separately set up another steam production system, which can reduce equipment investment and floor area and realize the cascaded utilization of energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the system structure diagram of the biomass gasification coupled with green electricity electrolyzed water to prepare green methanol in the embodiment;

[0016] Figure 2 It is the structure schematic diagram of the biomass gasification device;

[0017] Figure 3 It is the structure schematic diagram of the green methanol synthesis device.

[0018] Description of the reference numerals in the drawings:

[0019] 1. Biomass gasification reactor; 2. Dust removal and recovery system; 3. Cooling system; 4. Scrubbing tower; 5. Gas injection device; 6. Pressure control system; 7. Electrolyzed water device; 8. Methanol synthesis reactor; 9. Condensation system; 10. Rectification device; 11. Methanol buffer tank. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention.

[0021] This embodiment discloses a system for preparing green methanol by coupling biomass gasification with green electricity electrolysis of water, as Figures 1 to 3 shown, which mainly consists of the following parts: a biomass gasification device, an electrolytic water device 7 using green electricity, a green methanol synthesis device, and a collection and control system.

[0022] Among them, the biomass gasification device includes a biomass gasification reactor 1, a dust removal and recovery system 2, a cooling system 3, and a scrubber 4. A biomass feeding port is provided on the lower side of the biomass gasification reactor 1, a slag discharge port is provided at the bottom of the biomass gasification reactor 1, a biomass return port, a steam inlet, and an oxygen inlet are respectively provided on the lower side of the biomass gasification reactor 1 from top to bottom, and a pyrolysis gas discharge port is provided at the top of the biomass gasification reactor 1. Biomass (such as biomass straw) is fed into the biomass gasification reactor 1 through the biomass feeding port and converted into pyrolysis gas through a thermochemical reaction. The pyrolysis gas contains CO, CO2, and a small amount of H2. The pyrolysis gas is sent into the dust removal and recovery system 2 along the conveying pipeline through the pyrolysis gas discharge port. The dust removal and recovery system 2 performs dust removal treatment on the pyrolysis gas, and the unpyrolyzed biomass (including slag and insufficiently pyrolyzed substances) is re-sent into the biomass gasification reactor 1 through the pipeline connecting the biomass return port for re-pyrolysis. The dust-removed pyrolysis gas is transported to the cooling system 3 through the pipeline for cooling treatment of the pyrolysis gas, and the cooled pyrolysis gas is transported to the scrubber 4 through the pipeline for purification treatment, and impurities are removed after purification to form clean pyrolysis gas.

[0023] The electrolytic water device 7 in this embodiment includes an anion exchange membrane electrolyzer for hydrogen production (AEM), a hydrogen treatment and drying device, a water tank, a water treatment and purification system, and auxiliary equipment such as an AC-DC converter. Compared with the alkaline water electrolysis (AWE / Alk) device, the advantage of the AEM electrolyzer is that it combines the low cost of the alkaline electrolyzer with the simplicity and high efficiency of the PEM. It can use non-noble metal catalysts, has low requirements for various components such as electrode plates, and can use nickel-plated stainless steel plates. The PEM can also operate under pressure difference to achieve high-pressure hydrogen production. When the equipment is running, raw water enters from the cathode side of the AEM equipment. Water molecules participate in the reduction reaction at the cathode and gain electrons to generate hydroxide ions and hydrogen. After the hydroxide ions reach the anode through the polymer anion exchange membrane, they participate in the oxidation reaction and lose electrons to generate water and oxygen. Depending on the design of the equipment, sometimes a certain amount of KOH solution or NaHCO3 solution is added to the raw water as an auxiliary electrolyte, which helps to improve the working efficiency of the AEM electrolysis equipment.

[0024] The reaction formula for the electrolysis of water is as follows:

[0025] Cathode plate battery: 4H2O + 4e - = 2H2↑ + 4OH -

[0026] Anode plate battery: 4OH - → 2H2O + O2↑ + 4e -

[0027] The green methanol synthesis device in this embodiment is as shown in Figure 1 and Figure 3 shown, and mainly includes a gas filling device 5, a pressure control system 6, a methanol synthesis reactor 8, a condensation system 9, a rectification device 10, and a methanol buffer tank 11 that are connected in sequence. Among them, the gas filling device 5 includes a first compressor and a second compressor. The clean pyrolysis gas purified by the scrubber 4 is transported through a pipeline to the first compressor for compression treatment of the pyrolysis gas. The hydrogen generated by the electrolytic water device 7 is transported through a hydrogen transport pipeline to the second compressor for compression treatment. The compressed pyrolysis gas and hydrogen are together transported through the pressure control system 6 to the methanol synthesis reactor 8. The synthesis of methanol is carried out under high temperature, high pressure, and the presence of a catalyst, and its reaction equation is as follows:

[0028] CO + 2H2 → CH3OH

[0029] CO2 + 3H2 → CH3OH + H2O

[0030] It can be seen from the above reaction formulas that under the action of the catalyst, the methanol synthesis reactor 8 reacts the pyrolysis gas and hydrogen to generate methanol vapor and by-product water vapor. The methanol vapor generated by the methanol synthesis reactor 8 is transported to the condensation system 9, and the water vapor generated by the methanol synthesis reactor 8 is connected to the steam inlet of the biomass gasification reactor 1 through a pipeline. The oxygen generated by the electrolytic water device 7 is connected to the oxygen inlet of the biomass gasification reactor 1 through an oxygen transport pipeline. In the biomass gasification reactor 1, using the oxygen produced by electrolytic water as the gasifying agent and simultaneously introducing the water vapor generated by the methanol synthesis reactor 8 can promote the water gas reaction (C + H2O → CO + H2), thereby increasing the content of H2 in the pyrolysis gas, changing the CO / H2 ratio, and while improving the raw material conversion rate, reducing energy consumption and equipment investment.

[0031] This utility model synthesizes methanol directly in the methanol synthesis reactor 8 by using the hydrogen produced by electrolytic water and the CO and CO2 generated by biomass gasification without separation and purification treatment, and fixes the hydrogen energy in the form of methanol to ensure the output stability and reliability of the overall process and system.

[0032] In addition to the devices given above, the whole set of methanol preparation system of this utility model is also provided with a collection and control system, mainly including pressure monitoring and control, temperature monitoring and control, feed rate control, and intake volume interlock control, etc. For example, segmented temperature collection and control are carried out on the methanol synthesis reactor 8, the feed rate is controlled, and pressure monitoring and control are carried out on the methanol buffer tank 11.

[0033] Although embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A system for preparing green methanol by coupling biomass gasification with green electricity electrolysis of water, comprising a biomass gasification device, an electrolysis of water device and a green methanol synthesis device, characterized in that: The biomass gasification device includes a biomass gasification reactor, a dust removal and recovery system, a cooling system and a scrubber. The biomass gasification reactor is respectively provided with a biomass feeding port, a slag discharge port, a steam inlet, an oxygen inlet and a pyrolysis gas discharge port. The pyrolysis gas discharge port is connected to the dust removal and recovery system through a pipeline. The dust removal and recovery system is connected to the cooling system through a pipeline. The cooling system is connected to the scrubber through a pipeline. The bottom of the dust removal and recovery system is connected to the lower part of the biomass gasification reactor through a return pipeline; The electrolytic water device includes a fixed polymer anion exchange membrane hydrogen production electrolytic cell, and the electrolytic cell is connected to the oxygen inlet of the biomass gasification reactor through an oxygen transmission pipeline; The green methanol synthesis device includes a gas filling device, a pressure control system, a methanol synthesis reactor, a condensation system, a rectification device and a methanol buffer tank. The gas filling device includes a first compressor and a second compressor. The scrubber transports pyrolysis gas to the first compressor through a pipeline. The electrolytic cell transports hydrogen to the second compressor through a hydrogen transmission pipeline. The compressed pyrolysis gas and hydrogen are transported to the methanol synthesis reactor through the pressure control system. The steam generated by the methanol synthesis reactor is connected to the steam inlet of the biomass gasification reactor through a pipeline. The methanol steam generated by the methanol synthesis reactor is transported to the condensation system. The condensation system is connected to the rectification device through a pipeline. The rectification device is connected to the methanol buffer tank through a pipeline.

2. The system for preparing green methanol by coupling biomass gasification with green power electrolysis of water according to claim 1, wherein: The electrolytic water device further includes a hydrogen treatment and drying device, a water tank, a water treatment and purification system and an AC-DC converter.

3. The system for preparing green methanol by coupling biomass gasification with green electricity electrolysis of water according to claim 1, wherein: The system for preparing green methanol by coupling biomass gasification with green power electrolytic water further includes a pressure monitoring and control device, a temperature monitoring and control device, a feed rate control device and an intake air volume interlock control device.

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