System and method for hydrogen production and co-production of methanol and fresh water based on wastewater and biomass

Abstract

The invention relates to a system and a method for hydrogen production and co-production of methanol and fresh water based on wastewater and biomass. The system comprises a biomass combustion unit, an electrolyzed water coupling low-temperature distillation integrated system and a methanol preparation unit, wherein the electrolyzed water coupling low-temperature distillation integrated system comprises an alkaline electrolytic bath unit, an oxygen separation cooling unit, a hydrogen separation cooling unit, a hydrogen purification cooling unit, an alkali liquor circulating filtering unit and a unit for preparing fresh water from wastewater. The wastewater is directly introduced into the electrolyzed water coupling low-temperature distillation integrated system, prepared oxygen is supplied to the biomass combustion unit, the final product is effectively utilized, and the occupied area is small; fresh water generated by the wastewater-to-fresh water unit serves as an electrolyzed water raw material to be supplemented to the alkaline electrolytic cell unit, and dependence on fresh water resources is relieved; and the wastewater and the biomass are finally and completely changed into high-concentration hydrogen, oxygen, fresh water and methanol, the generated fresh water is far superior to the traditional wastewater which reaches the standard and is discharged, and the resource utilization of the wastewater is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass and wastewater development and utilization, and in particular to a system and method for co-producing methanol and fresh water based on wastewater and biomass hydrogen production. Background Art

[0002] At present, in the global and domestic energy structure, fossil fuels such as coal and oil dominate the power industry. The consumption of coal and natural gas is very large, and thermal power generation has become the main source of harmful gas emissions, posing a threat to energy development and the ecological environment. Biomass energy can be converted into conventional solid, liquid and gaseous fuels. It is inexhaustible and is a renewable energy source. It is also the only renewable carbon source.

[0003] The existing technical routes for treating chemical wastewater are complex and diverse, and most of them require wastewater pretreatment, biochemical treatment, deep treatment and brine treatment. After the high-salt wastewater is concentrated and crystallized to recover water, its salt is treated as hazardous waste landfill. Chemical wastewater is only treated to meet provincial or national emission standards. The treated wastewater cannot be reused and is discharged into urban sewage pipe networks or other places. At present, the treatment method of industrial wastewater is more based on post-treatment discharge, and there is not much resource utilization of industrial wastewater. The above-mentioned wastewater treatment process has the disadvantages of high energy consumption, high operating costs, and certain negative impacts on the environment. In addition, various treatment devices are connected by pipelines, the overall footprint is large, and the utilization rate of the plant area is low.

[0004] Hydrogen energy is regarded as the clean energy with the greatest development potential in the 21st century. Using green electricity generated by renewable energy such as solar energy and wind energy to drive the electrolysis of water to produce hydrogen is of great significance to solving the problem of energy shortage and achieving the "dual carbon" goal. Among the current water electrolysis hydrogen production technologies, alkaline water electrolysis has a low cost and relatively mature technology. It is the most widely industrialized hydrogen production technology and occupies a dominant position. The "Global Water Use Report for Hydrogen Production" released by the International Renewable Energy Agency (IRENA) shows that the current mainstream hydrogen production methods in the world require fresh water, mainly concentrated in the two major processes of hydrogen production and cooling. About 32.2 liters of fresh water are required to produce 1 kilogram of blue hydrogen. In the production of green hydrogen, the amount of fresh water consumed by the alkaline water electrolysis hydrogen production process to produce 1 kilogram of hydrogen is estimated to be 22.3 liters. However, global fresh water resources are extremely limited, and the large-scale promotion and application of water electrolysis hydrogen production technology will undoubtedly aggravate the problem of fresh water shortage.

[0005] Methanol is also known as "liquid sunshine". In 2018, the Chinese Academy of Sciences established a "Liquid Sunshine" task force to study methanol fuel. The task force believes that methanol can be divided into five generations based on its source. The fourth generation is biomass methanol, also known as green methanol. Summary of the invention

[0006] According to the technical problems raised above, a system and method for co-producing methanol and fresh water based on wastewater and biomass hydrogen production is provided. The present invention can achieve low-cost treatment of wastewater and biomass waste, save the floor space of wastewater treatment equipment and biomass treatment equipment, and achieve efficient production of methanol.

[0007] The technical means adopted by the present invention are as follows:

[0008] A system for producing methanol and fresh water based on wastewater and biomass hydrogen production, comprising: a biomass combustion unit, an electrolytic water coupled low-temperature distillation integrated system and a methanol preparation unit, wherein the electrolytic water coupled low-temperature distillation integrated system comprises an alkaline electrolyzer unit, an oxygen separation cooling unit, a hydrogen separation cooling unit, a hydrogen purification cooling unit, an alkali liquid circulation filtration unit and a wastewater fresh water unit, wherein the electrolytic water coupled low-temperature distillation integrated system collects water to be treated, and the wastewater fresh water unit is used to heat the water to be treated, and steam is used to remove impurities and condense to produce fresh water; the output end of the wastewater fresh water unit is connected to the alkaline electrolyzer unit, and the fresh water in the alkaline electrolyzer unit is directly discharged into the fresh water tank; Under the action of electricity, it is decomposed into hydrogen and oxygen, hydrogen and alkali liquid enter the hydrogen separation cooling unit, and oxygen and alkali liquid enter the oxygen separation cooling unit; the hydrogen purification cooling unit is used to complete the purification of hydrogen, and the alkali liquid circulation filtration unit is used to complete the forced circulation of alkali liquid in the alkaline electrolyzer unit and the hydrogen separation cooling unit and the oxygen separation cooling unit. The biomass combustion unit is connected to the oxygen outlet of the electrolysis water coupled low-temperature distillation integrated system. After the biomass combustion unit obtains the biomass, it reacts with oxygen to generate carbon dioxide. The output end of the biomass combustion unit is connected to the methanol preparation unit, and the hydrogen from the electrolysis water coupled low-temperature distillation integrated system is also transported to the methanol preparation unit.

[0009] Furthermore, an output end of the biomass combustion unit is connected to a water treatment unit, a portion of the produced water of the water treatment unit is collected, and another portion of the produced water is used as a supplementary water source for the electrolytic water coupled low-temperature distillation integrated system.

[0010] Furthermore, the wastewater includes inorganic wastewater and / or organic wastewater.

[0011] Furthermore, when the wastewater is organic wastewater, the organic wastewater enters the wastewater desalination unit after passing through the oxidation treatment unit.

[0012] Furthermore, the wastewater to be treated enters into the wastewater to fresh water unit or enters into the hydrogen separation cooling unit or the oxygen separation cooling unit.

[0013] Furthermore, the hydrogen outlet of the alkaline electrolyzer module is connected to the hydrogen separation cooling unit, the oxygen outlet of the alkaline electrolyzer module is connected to the oxygen separation cooling unit, the alkali liquid inlet of the alkaline electrolyzer module is connected to the wastewater-to-fresh water unit, the oxygen separation cooling unit separates oxygen and alkali liquid by a gas-liquid separation method, the hydrogen separation cooling unit separates hydrogen and alkali liquid by a gas-liquid separation method, the hydrogen outlet of the hydrogen separation cooling unit is connected to the hydrogen purification cooling unit, the alkali liquid outlet of the oxygen separation cooling unit and the alkali liquid outlet of the hydrogen separation cooling unit are both connected to the alkali liquid circulation filtration unit to provide high-temperature alkali liquid to be cooled, and the fresh water outlet of the wastewater-to-fresh water unit is connected to the hydrogen separation cooling unit.

[0014] Furthermore, the wastewater-to-fresh water unit includes a device cylinder, a vacuum system, a condenser, a water receiving plate, and a wire mesh separator. The device cylinder is provided with a vacuum system connection port, a wastewater inlet port, a concentrated brine outlet port, a fresh water outlet port, and an alkali solution circulation pipe. The device cylinder is connected to the vacuum system through the vacuum system connection port, and is connected to the wastewater derivation unit or the oxygen separation cooling unit / hydrogen separation cooling unit through the wastewater inlet port. The concentrated brine outlet port is used to collect concentrated brine. The alkali solution circulation pipe is used to exchange heat between high-temperature alkali solution and wastewater, reduce the alkali solution temperature and make the wastewater reach the evaporation temperature and evaporate into water vapor. The water vapor is condensed by the condenser. The water receiving plate is used to receive condensed water droplets, and its output end is connected to the fresh water outlet. A wire mesh separator is arranged in the device cylinder, which is used to separate larger droplets and impurities in the water vapor.

[0015] Furthermore, the alkaline electrolytic cell used specifically includes a cathode end plate and an anode end plate, and at least one electrolytic cell unit composed of a bipolar plate is arranged between the cathode end plate and the anode end plate; the cathode end plate, the bipolar plate and the anode end plate all include a plate body, and positioning holes, fastening holes, an alkali solution inlet, a gas outlet (i.e., an alkali solution and hydrogen outlet or an alkali solution and oxygen outlet) and a guide component are arranged at corresponding positions of each plate; the guide components of the cathode end plate and the anode end plate are opened on the inner side close to the bipolar plate, and a flow channel for connecting the alkali solution inlet and the gas outlet is opened in the middle position of the end surface of the plate body, and the guide component divides the flow channel in a preset form, and the guide component specifically includes a blocking mechanism and a guide mechanism, and the guide mechanism is arranged on the alkali solution inlet side and the gas outlet side, and the blocking mechanism is a plurality of array-distributed nipples, including a central nipple and an annularly distributed nipple with the central nipple as the center and arranged in its circumference at a preset interval.

[0016] Furthermore, the cathode end plate, the bipolar plate and the anode end plate are divided into a plate body and a plate frame by sealing grooves. The plate body is arranged inside the plate frame. There are multiple groups of sealing grooves in a circumferential direction. The sealing grooves protrude from the plate body and the plate frame by a preset distance. A number of positioning holes are opened on the plate body, and a number of mounting holes are opened on the plate frame along its circumference.

[0017] Furthermore, the flow guiding mechanism is a plurality of partition plates arranged at intervals perpendicular to the alkali solution inlet and the gas outlet. By arranging the partition plates, the fluid is evenly dispersed to enter / flow out of the flow channel between the mastoids.

[0018] Furthermore, grooves for installing upper gaskets and lower gaskets are provided on the end surfaces of the alkali solution inlet and the gas outlet, and the shapes of the grooves match the gaskets.

[0019] Furthermore, a support column is provided at the bottom of the board frame of the preset board.

[0020] A method for co-producing methanol and fresh water based on wastewater and biomass hydrogen production, comprising the following steps:

[0021] The electrolysis water coupling low temperature distillation integrated system is connected to the wastewater source and biomass combustion unit to start the wastewater and biomass hydrogen production co-production of methanol and fresh water, among which,

[0022] The wastewater is directly transported to the wastewater desalination unit for desalination or enters the wastewater desalination unit after passing through the oxygen separation cooling unit and the hydrogen separation cooling unit. The wastewater can play an auxiliary cooling role in the oxygen separation cooling unit and the hydrogen separation cooling unit.

[0023] Fresh water in the alkaline electrolyser unit is decomposed into hydrogen and oxygen by direct current;

[0024] The oxygen outlet of the alkaline electrolyzer unit transports oxygen and alkaline solution to the oxygen separation cooling unit for gas-liquid separation;

[0025] The hydrogen outlet of the alkaline electrolyzer unit transports hydrogen and alkali liquid to the hydrogen separation cooling unit for gas-liquid separation. The hydrogen and a small amount of water after preliminary purification enter the hydrogen purification cooling unit for further purification to a hydrogen content of ≥99.99%;

[0026] The alkali liquid circulation filtration unit extracts the alkali liquid from the oxygen separation cooling unit and the hydrogen separation cooling unit, cools it in the wastewater to fresh water unit, and finally transports it to the alkaline electrolyzer unit to complete the cooling and forced circulation of the alkali liquid;

[0027] The heat emitted by the alkali solution during cooling in the wastewater-to-freshwater unit is used to heat the wastewater under negative pressure to produce fresh water. The produced fresh water is transported to the hydrogen separation module to supplement the raw fresh water used for electrolysis, and also assists in hydrogen scrubbing and cooling.

[0028] The biomass combustion unit uses oxygen generated by water electrolysis to burn biomass to produce a certain amount of CO2;

[0029] The hydrogen discharged from the hydrogen purification cooling unit and the CO2 discharged from the biomass combustion unit enter the methanol preparation unit together for the preparation of methanol;

[0030] The water produced by the biomass combustion unit is used as a supplementary water source for the production of fresh water from wastewater.

[0031] Furthermore, when the wastewater is organic wastewater, the organic wastewater is also subjected to oxidation treatment before entering the integrated system for electrolysis of water coupled with cryogenic distillation, and the oxygen source can be selected from oxidant addition or oxygen generated by the integrated system for electrolysis of water coupled with cryogenic distillation.

[0032] Compared with the prior art, the present invention has the following advantages: the traditional biomass methanol production process requires a large amount of oxygen to be stored and occupies a large area; the traditional wastewater treatment process occupies a large area and has a complex process flow. The present invention directly introduces wastewater into the electrolytic water coupled low-temperature distillation integrated system, and supplies the prepared oxygen to the biomass combustion unit, so that the final product is effectively utilized and occupies a small area; the electrolytic water coupled low-temperature distillation integrated system uses the alkali solution that needs to be cooled to heat the wastewater in a negative pressure environment. While the alkali solution is cooled, the heat emitted when the alkali solution is cooled is also utilized. The fresh water generated by the wastewater fresh water unit is used as an electrolytic water raw material to supplement the alkaline electrolytic cell unit, thereby alleviating dependence on fresh water resources; the wastewater and biomass are finally completely converted into high-concentration hydrogen, oxygen, fresh water, and methanol. The generated fresh water is far superior to the traditional standard-discharged wastewater, and the resource utilization of wastewater is realized. In addition, the generated oxygen can also be used as a source of oxidation treatment to complete the internal circulation of the system, and the final product is effectively utilized. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 This is a schematic diagram of the system for co-producing methanol and fresh water based on wastewater and biomass hydrogen production according to the present invention.

[0035] Figure 2 It is a schematic diagram of the overall structure of the alkaline electrolytic cell of the present invention.

[0036] Figure 3 It is a side view of the overall structure of the alkaline electrolytic cell of the present invention.

[0037] Figure 4 Schematic diagram of the bipolar plate structure of the present invention.

[0038] Figure 5 This is a front view of the bipolar plate of the present invention.

[0039] Figure 6 For the present invention Figure 5AA cross-section of the bipolar plate.

[0040] Figure 7 It is a side view of the bipolar plate of the present invention.

[0041] Figure 8 It is a schematic diagram of the end plate structure of the present invention.

[0042] Fig. 9 It is the front view of the end plate of the present invention.

[0043] Fig.10 For the present invention Fig. 9 AA section of the end plate.

[0044] Fig.11 It is a side view of the end plate of the present invention.

[0045] Fig.12 Schematic diagram of the bipolar plate gasket of the present invention.

[0046] Fig.13 It is a schematic diagram of the end plate gasket of the present invention.

[0047] In the figure: 1. alkali solution inlet; 2. gas outlet; 3. sealing groove; 4. mastoid; 5. positioning hole; 6. fastening hole; 7. support column; 8. upper gasket; 9. lower gasket. DETAILED DESCRIPTION

[0048] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0049] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. 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.

[0050] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0051] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, the numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0052] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0053] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0054] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0055] like Figure 1As shown, an embodiment of the present invention discloses a system for co-producing methanol and fresh water based on wastewater and biomass hydrogen production, including: a biomass combustion unit, an electrolytic water coupled low-temperature distillation integrated system and a methanol preparation unit, the electrolytic water coupled low-temperature distillation integrated system includes an alkaline electrolyzer unit, an oxygen separation cooling unit, a hydrogen separation cooling unit, a hydrogen purification cooling unit, an alkali liquid circulation filtration unit and a wastewater fresh water unit, the electrolytic water coupled low-temperature distillation integrated system collects water to be treated, the wastewater fresh water unit is used to heat the water to be treated, steam removes impurities and condenses to produce fresh water; the output end of the wastewater fresh water unit is connected to the alkaline electrolyzer unit, and the alkaline electrolyzer unit The fresh water is decomposed into hydrogen and oxygen under the action of direct current, and the hydrogen and alkali liquid enter the hydrogen separation cooling unit, and the oxygen and alkali liquid enter the oxygen separation cooling unit; the hydrogen purification cooling unit is used to complete the purification of hydrogen, and the alkali liquid circulation filtration unit is used to complete the forced circulation of alkali liquid in the alkaline electrolyzer unit and the hydrogen separation cooling unit and the oxygen separation cooling unit. The biomass combustion unit is connected to the oxygen outlet of the electrolysis water coupled low-temperature distillation integrated system. After obtaining the biomass, the biomass combustion unit reacts with oxygen to generate carbon dioxide. The output end of the biomass combustion unit is connected to the methanol preparation unit, and the hydrogen from the electrolysis water coupled low-temperature distillation integrated system is also transported to the methanol preparation unit.

[0056] Furthermore, an output end of the biomass combustion unit is connected to a water treatment unit, a portion of the produced water of the water treatment unit is collected, and another portion of the produced water is used as a supplementary water source for the electrolytic water coupled low-temperature distillation integrated system.

[0057] Furthermore, the wastewater includes inorganic wastewater and / or organic wastewater.

[0058] Furthermore, when the wastewater is organic wastewater, the organic wastewater enters the wastewater desalination unit after passing through the oxidation treatment unit.

[0059] Furthermore, the wastewater to be treated enters a wastewater-to-freshwater unit or a hydrogen separation cooling unit or an oxygen separation cooling unit.

[0060] Furthermore, the hydrogen outlet of the alkaline electrolyzer module is connected to the hydrogen separation cooling unit, the oxygen outlet of the alkaline electrolyzer module is connected to the oxygen separation cooling unit, the alkali liquid inlet of the alkaline electrolyzer module is connected to the wastewater-to-fresh water unit, the oxygen separation cooling unit separates oxygen and alkali liquid by a gas-liquid separation method, the hydrogen separation cooling unit separates hydrogen and alkali liquid by a gas-liquid separation method, the hydrogen outlet of the hydrogen separation cooling unit is connected to the hydrogen purification cooling unit, the alkali liquid outlet of the oxygen separation cooling unit and the alkali liquid outlet of the hydrogen separation cooling unit are both connected to the alkali liquid circulation filtration unit to provide high-temperature alkali liquid to be cooled, and the fresh water outlet of the wastewater-to-fresh water unit is connected to the hydrogen separation cooling unit.

[0061] Furthermore, the wastewater-to-fresh water unit includes a device cylinder, a vacuum system, a condenser, a water receiving plate, and a wire mesh separator. The device cylinder is provided with a vacuum system connection port, a wastewater inlet port, a concentrated brine outlet port, a fresh water outlet port, and an alkali solution circulation pipe. The device cylinder is connected to the vacuum system through the vacuum system connection port, and is connected to the wastewater derivation unit or the oxygen separation cooling unit / hydrogen separation cooling unit through the wastewater inlet port. The concentrated brine outlet port is used to collect concentrated brine. The alkali solution circulation pipe is used to exchange heat between high-temperature alkali solution and wastewater, reduce the alkali solution temperature and make the wastewater reach the evaporation temperature and evaporate into water vapor. The water vapor is condensed by the condenser. The water receiving plate is used to receive condensed water droplets, and its output end is connected to the fresh water outlet. A wire mesh separator is arranged in the device cylinder, which is used to separate larger droplets and impurities in the water vapor.

[0062] like Figures 2 to 13 As shown, the alkaline electrolytic cell used in the embodiment of the present invention specifically includes a cathode end plate and an anode end plate, and at least one electrolytic cell unit composed of a bipolar plate is arranged between the cathode end plate and the anode end plate; the cathode end plate, the bipolar plate and the anode end plate all include a plate body, and positioning holes 5, fastening holes 6, an alkali solution inlet 1, a gas outlet 2 (i.e., an alkali solution and hydrogen outlet or an alkali solution and oxygen outlet) and a guide component are arranged at corresponding positions of each plate; the guide components of the cathode end plate and the anode end plate are opened on the inner side close to the bipolar plate, and a flow channel for connecting the alkali solution inlet and the gas outlet is opened in the middle position of the end surface of the plate body, and the guide component divides the flow channel in a preset form, and the guide component specifically includes a blocking mechanism and a guide mechanism, and the guide mechanism is arranged on the alkali solution inlet side and the gas outlet side, and the blocking mechanism is a plurality of array-distributed nipples 4, including a central nipple and an annularly distributed nipple with the central nipple as the center and arranged in its circumference at a preset interval.

[0063] Furthermore, the cathode end plate, the bipolar plate and the anode end plate are divided into a plate body and a plate frame by a sealing groove 3. The plate body is arranged inside the plate frame. There are multiple groups of sealing grooves arranged in a circumferential direction. The sealing grooves protrude from the plate body and the plate frame by a preset distance. A plurality of positioning holes are opened on the plate body, and a plurality of mounting holes are opened on the plate frame along its circumference.

[0064] Furthermore, the flow guiding mechanism is a plurality of partition plates arranged at intervals perpendicular to the alkali solution inlet and the gas outlet. By arranging the partition plates, the fluid is evenly dispersed to enter / flow out of the flow channel between the mastoids.

[0065] Furthermore, grooves for installing the upper gasket 8 and the lower gasket 9 are provided on the end surfaces of the alkali solution inlet and the gas outlet, and the shapes of the grooves match the gaskets.

[0066] Furthermore, a support column 7 is provided at the bottom of the frame of the preset plate.

[0067] A method for co-producing methanol and fresh water based on wastewater and biomass hydrogen production, comprising the following steps:

[0068] The electrolysis water coupling low temperature distillation integrated system is connected to the wastewater source and biomass combustion unit to start the wastewater and biomass hydrogen production co-production of methanol and fresh water, among which,

[0069] The wastewater is directly transported to the wastewater desalination unit for desalination or enters the wastewater desalination unit after passing through the oxygen separation cooling unit and the hydrogen separation cooling unit. The wastewater can play an auxiliary cooling role in the oxygen separation cooling unit and the hydrogen separation cooling unit.

[0070] Fresh water in the alkaline electrolyser unit is decomposed into hydrogen and oxygen by direct current;

[0071] The oxygen outlet of the alkaline electrolyzer unit transports oxygen and alkaline solution to the oxygen separation cooling unit for gas-liquid separation;

[0072] The hydrogen outlet of the alkaline electrolyzer unit transports hydrogen and alkali liquid to the hydrogen separation cooling unit for gas-liquid separation. The hydrogen and a small amount of water after preliminary purification enter the hydrogen purification cooling unit for further purification to a hydrogen content of ≥99.99%;

[0073] The alkali liquid circulation filtration unit extracts the alkali liquid from the oxygen separation cooling unit and the hydrogen separation cooling unit, cools it in the wastewater to fresh water unit, and finally transports it to the alkaline electrolyzer unit to complete the cooling and forced circulation of the alkali liquid;

[0074] The heat emitted by the alkali solution during cooling in the wastewater-to-freshwater unit is used to heat the wastewater under negative pressure to produce fresh water. The produced fresh water is transported to the hydrogen separation module to supplement the raw fresh water used for electrolysis, and also assists in hydrogen scrubbing and cooling.

[0075] The biomass combustion unit uses oxygen generated by water electrolysis to burn biomass to produce a certain amount of CO2;

[0076] The hydrogen discharged from the hydrogen purification cooling unit and the CO2 discharged from the biomass combustion unit enter the methanol preparation unit together for the preparation of methanol;

[0077] The water produced by the biomass combustion unit is used as a supplementary water source for the production of fresh water from wastewater.

[0078] Furthermore, when the wastewater is organic wastewater, the organic wastewater is also subjected to oxidation treatment before entering the integrated system for electrolysis of water coupled with cryogenic distillation, and the oxygen source can be selected from oxidant addition or oxygen generated by the integrated system for electrolysis of water coupled with cryogenic distillation.

[0079] 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 system for producing methanol and fresh water based on wastewater and biomass hydrogen production, characterized in that: include: A biomass combustion unit, an electrolytic water coupled low-temperature distillation integrated system and a methanol preparation unit, wherein the electrolytic water coupled low-temperature distillation integrated system comprises an alkaline electrolytic cell unit, an oxygen separation cooling unit, a hydrogen separation cooling unit, a hydrogen purification cooling unit, an alkali solution circulation filtration unit and a wastewater desalination unit, wherein the electrolytic water coupled low-temperature distillation integrated system collects water to be treated, and the wastewater desalination unit is used to heat the water to be treated, and steam is used to remove impurities and condense to produce fresh water; the output end of the wastewater desalination unit is connected to the alkaline electrolytic cell unit, and the fresh water in the alkaline electrolytic cell unit is decomposed into hydrogen and oxygen under the action of direct current. Gas, hydrogen and alkali liquid enter the hydrogen separation cooling unit, and oxygen and alkali liquid enter the oxygen separation cooling unit; the hydrogen purification cooling unit is used to complete the purification of hydrogen, and the alkali liquid circulation filtration unit is used to complete the forced circulation of alkali liquid in the alkaline electrolyzer unit and the hydrogen separation cooling unit and the oxygen separation cooling unit. The biomass combustion unit is connected to the oxygen outlet of the electrolysis water coupled low-temperature distillation integrated system. After the biomass combustion unit obtains the biomass, it reacts with oxygen to generate carbon dioxide. The output end of the biomass combustion unit is connected to the methanol preparation unit, and the hydrogen of the electrolysis water coupled low-temperature distillation integrated system is also transported to the methanol preparation unit.

2. The system for producing methanol and fresh water based on wastewater and biomass hydrogen production according to claim 1, characterized in that: An output end of the biomass combustion unit is connected to a water treatment unit, a portion of the produced water of the water treatment unit is collected, and another portion of the produced water is used as a supplementary water source for an electrolytic water coupled low-temperature distillation integrated system.

3. The system for producing methanol and fresh water based on wastewater and biomass hydrogen production according to claim 1, characterized in that: The wastewater includes inorganic wastewater and / or organic wastewater.

4. The system for producing methanol and fresh water based on wastewater and biomass hydrogen production according to claim 1, characterized in that: When the wastewater is organic wastewater, the organic wastewater enters the wastewater desalination unit after passing through the oxidation treatment unit.

5. The system for co-producing methanol and fresh water based on wastewater and biomass hydrogen production according to claim 1, characterized in that: The wastewater to be treated enters the wastewater-to-freshwater unit or the hydrogen separation cooling unit or the oxygen separation cooling unit.

6. The system for co-producing methanol and fresh water based on wastewater and biomass hydrogen production according to claim 1, characterized in that: The hydrogen outlet of the alkaline electrolyzer module is connected to the hydrogen separation cooling unit, the oxygen outlet of the alkaline electrolyzer module is connected to the oxygen separation cooling unit, the alkali liquid inlet of the alkaline electrolyzer module is connected to the wastewater desalination unit, the oxygen separation cooling unit separates oxygen and alkali liquid by a gas-liquid separation method, the hydrogen separation cooling unit separates hydrogen and alkali liquid by a gas-liquid separation method, the hydrogen outlet of the hydrogen separation cooling unit is connected to the hydrogen purification cooling unit, the alkali liquid outlet of the oxygen separation cooling unit and the alkali liquid outlet of the hydrogen separation cooling unit are both connected to the alkali liquid circulation filtration unit to provide high-temperature alkali liquid to be cooled, and the fresh water outlet of the wastewater desalination unit is connected to the hydrogen separation cooling unit.

7. The system for co-producing methanol and fresh water based on wastewater and biomass hydrogen production according to claim 1, characterized in that: The wastewater-to-freshwater unit comprises a device cylinder, a vacuum system, a condenser, a water receiving plate, and a wire mesh separator. The device cylinder is provided with a vacuum system connection port, a wastewater inlet port, a concentrated brine outlet port, a fresh water outlet port, and an alkali solution circulation pipe. The device cylinder is connected to the vacuum system via the vacuum system connection port, and is connected to the wastewater derivation unit or the oxygen separation cooling unit / hydrogen separation cooling unit via the wastewater inlet port. The concentrated brine outlet port is used to collect concentrated brine. The alkali solution circulation pipe is used to exchange heat between high-temperature alkali solution and wastewater, reduce the temperature of the alkali solution, and make the wastewater reach the evaporation temperature and evaporate into water vapor. The water vapor is condensed by the condenser. The water receiving plate is used to receive condensed water droplets, and its output end is connected to the fresh water outlet. A wire mesh separator is provided in the device cylinder, which is used to separate larger droplets and impurities in the water vapor.

8. The system for co-producing methanol and fresh water based on wastewater and biomass hydrogen production according to claim 7, characterized in that: An alkaline electrolytic cell, specifically comprising a cathode end plate and an anode end plate, wherein at least one electrolytic cell unit consisting of a bipolar plate is arranged between the cathode end plate and the anode end plate; the flow guide components of the cathode end plate and the anode end plate are opened on the inner side close to the bipolar plate, and a flow channel for connecting an alkali solution inlet and a gas outlet is opened in the middle of the end surface of the plate body, and the flow channel is divided into a preset form by the flow guide component, and the flow guide component specifically comprises a blocking mechanism and a flow guide mechanism, wherein the flow guide mechanism is arranged on the alkali solution inlet side and the gas outlet side, and the blocking mechanism is a plurality of array-shaped nipples, including a central nipple and annularly distributed nipples arranged in a preset interval around the central nipple as the center of the circle; The flow guiding mechanism is a plurality of partition plates arranged perpendicularly to the alkali solution inlet and the gas outlet. By arranging the partition plates, the fluid is evenly dispersed to enter / flow out of the flow channel between the mastoids.

9. A method for producing methanol and fresh water by using wastewater and biomass to produce hydrogen, characterized in that: The steps include: The electrolysis water coupling low temperature distillation integrated system is connected to the wastewater source and biomass combustion unit to start the wastewater and biomass hydrogen production co-production of methanol and fresh water, among which, The wastewater is directly transported to the wastewater desalination unit for desalination or enters the wastewater desalination unit after passing through the oxygen separation cooling unit and the hydrogen separation cooling unit. The wastewater can play an auxiliary cooling role in the oxygen separation cooling unit and the hydrogen separation cooling unit. Fresh water in the alkaline electrolyser unit is decomposed into hydrogen and oxygen by direct current; The oxygen outlet of the alkaline electrolyzer unit transports oxygen and alkaline solution to the oxygen separation cooling unit for gas-liquid separation; The hydrogen outlet of the alkaline electrolyzer unit transports hydrogen and alkali liquid to the hydrogen separation cooling unit for gas-liquid separation. The hydrogen and a small amount of water after preliminary purification enter the hydrogen purification cooling unit for further purification to a hydrogen content of ≥99.99%; The alkali liquid circulation filtration unit extracts the alkali liquid from the oxygen separation cooling unit and the hydrogen separation cooling unit, cools it in the wastewater to fresh water unit, and finally transports it to the alkaline electrolyzer unit to complete the cooling and forced circulation of the alkali liquid; The heat emitted by the alkali solution during cooling in the wastewater-to-freshwater unit is used to heat the wastewater under negative pressure to produce fresh water. The produced fresh water is transported to the hydrogen separation module to supplement the raw fresh water used for electrolysis, and also assists in hydrogen scrubbing and cooling. The biomass combustion unit uses oxygen generated by water electrolysis to burn biomass to produce a certain amount of CO2; The hydrogen discharged from the hydrogen purification cooling unit and the CO2 discharged from the biomass combustion unit enter the methanol preparation unit together for the preparation of methanol; The water produced by the biomass combustion unit is used as a supplementary water source for the production of fresh water from wastewater.

10. The method according to claim 9, characterized in that When the wastewater is organic wastewater, the organic wastewater is also subjected to oxidation treatment before entering the integrated system for electrolysis of water coupled with low-temperature distillation, and the oxygen source can be selected from oxidant addition or oxygen generated by the integrated system for electrolysis of water coupled with low-temperature distillation.

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