Production device and production method of electronic-grade hydrogen

Abstract

The invention discloses a production device and a production method of electronic-grade hydrogen, and the production device comprises a mixing tank, a heat exchanger, a vaporizer, a methanol catalytic cracking reactor, a cooler, a purification tower and a pressure swing adsorption tower group, the production method specifically comprises the following steps: (1) mixing a methanol solution with desalted water; (2) carrying out heat exchange, heating and vaporizing; (3) catalytic cracking conversion; (4) heat exchange and cooling; (5) washing and purifying; and (6) adsorption. Equipment is safe in operation, convenient in raw material source, convenient in transportation and storage, stable in price, simple in technological process, highly automatic in equipment, simple and easy in production operation, small in occupied area, low in equipment investment cost, low in production cost, short in recovery period, high in product quality and capable of fully utilizing residual heat energy, and the obtained electronic-grade hydrogen meets the national standard. The device is simple in structure, high in stability and capable of achieving continuous operation, meets the requirement of a high-end market and has a great market application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic industry, and more particularly to a production device and a production method of electronic-grade hydrogen. Background Art

[0002] High-purity hydrogen is mainly used in semiconductors, electronics and petrochemical industries, among which the electronics industry is the market with the highest application demand, and has a high application demand in the production of electric vacuum materials, semiconductors, electron tubes, and amorphous silicon films. In high-end manufacturing industries such as electronics, fine chemicals and pharmaceutical intermediates, product quality is highly related to the purity of upstream gases, so higher purity high-purity hydrogen is often used. In the manufacture of fine chemicals and pharmaceutical intermediates, high-purity hydrogen is one of the basic raw materials, and the purity of hydrogen has a great impact on product quality and energy consumption. In various hydrogenation industries using catalysts, the level of impurities in hydrogen determines the expensive catalyst life and product qualification rate, and thus determines the cost of the product. Therefore, the use of high-purity hydrogen can effectively improve product quality and profitability.

[0003] At present, the methods for refining high-purity hydrogen mainly include: condensation-low temperature adsorption method, low temperature absorption-adsorption method, pressure swing adsorption method, palladium membrane diffusion method, metal hydride method and the combined use of these methods. CN117160372A discloses a reaction device for producing hydrogen from methanol, which can improve the efficiency of producing hydrogen from methanol, but there is no purification operation and it is impossible to obtain products that meet industrial requirements; CN117839608A discloses a methanol hydrogen production device, which can improve the economic and environmental benefits of producing hydrogen from methanol, but the operation of the device is complicated and difficult to maintain; CN117658069A discloses a methanol hydrogen production system and a methanol hydrogen production process, which can achieve efficient utilization of thermal energy and low energy consumption, but the product obtained by this process has more impurities and cannot meet the needs of the market.

[0004] Therefore, taking into account many factors such as the economy of the device, the flexibility and reliability of the process, the difficulty of capacity expansion, the hydrogen content of the raw materials, the hydrogen purity requirements, and the impact of the impurity content on downstream devices, how to develop a device and method for producing high-purity electronic-grade hydrogen is an issue that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In view of this, an object of the present invention is to provide an electronic grade hydrogen production device and a production method thereof to solve the deficiencies in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] An electronic grade hydrogen production device comprises a mixing tank, a heat exchanger, a vaporizer, a methanol catalytic cracking reactor, a cooler, a purification tower and a pressure swing adsorption tower group;

[0008] Among them, the mixing tank, heat exchanger, cooler, purification tower and pressure swing adsorption tower group are connected in sequence;

[0009] The heat exchanger, vaporizer, methanol catalytic cracking reactor and heat exchanger are cyclically connected;

[0010] The purification tower and mixing tank are connected.

[0011] Furthermore, the pressure swing adsorption tower group consists of 6 towers connected in parallel, including pressure swing adsorption tower I, pressure swing adsorption tower II, pressure swing adsorption tower III, pressure swing adsorption tower IV, pressure swing adsorption tower V and pressure swing adsorption tower VI.

[0012] A further beneficial effect of adopting the above method is that the pressure swing adsorption tower of the present invention is composed of 6 pressure swing adsorption towers working alternately according to a program, and can continuously obtain high-purity electronic grade hydrogen, and can realize the online tower cutting function.

[0013] A method for producing electronic-grade hydrogen, using the above-mentioned electronic-grade hydrogen production device, specifically comprises the following steps:

[0014] (1) mixing methanol solution and desalted water in a mixing tank to obtain a mixed solution;

[0015] (2) passing the mixed liquid into a heat exchanger to perform a first heat exchange with the high-temperature reformed gas obtained in the catalytic cracking conversion process, and then passing the mixed liquid into a vaporizer after the temperature is increased, and then the temperature is increased again and vaporized into gas to obtain vaporized gas;

[0016] (3) passing the vaporized gas into a methanol catalytic cracking reactor filled with a catalyst for catalytic cracking conversion to generate a high-temperature conversion gas;

[0017] (4) passing the high-temperature reformed gas into a heat exchanger to perform a second heat exchange with the mixed liquid, and then passing the high-temperature reformed gas into a cooler for cooling to obtain cooled gas;

[0018] (5) The cooling gas is introduced into the purification tower from the bottom of the tower, flowing from bottom to top, and the washing liquid is introduced into the purification tower from the top of the tower, flowing from top to bottom. The cooling gas and the washing liquid are in countercurrent contact to perform washing and purification. The washing liquid obtained at the bottom of the tower is introduced into a mixing tank for recycling, and the purified gas is obtained at the top of the tower;

[0019] (6) The purified gas is passed into a pressure swing adsorption tower group filled with adsorbent for adsorption, and finally an electronic grade hydrogen product is obtained at the top of the pressure swing adsorption tower group.

[0020] Furthermore, in the above step (1), the salt content of the desalted water is 1-5 mg / L; the mass ratio of the methanol solution to the desalted water is (1-2):1, preferably 1.8:1.

[0021] The further beneficial effect of adopting the above method is that the present invention mixes the methanol solution with the desalted water, which has the following effects: 1. increasing the reaction rate, which is conducive to the occurrence of subsequent reactions; 2. changing the solubility of the methanol solution; 3. controlling the reaction conditions; 4. reducing the corrosion of the methanol solution to the metal; 5. the catalyst of the methanol cracking reaction will react with the chloride ions in the desalted water to generate copper chloride, which makes the catalyst inactive.

[0022] Furthermore, in the above step (2), the temperature is raised to 180°C and then introduced into a vaporizer, and the temperature is raised to 200°C again and vaporized into gas.

[0023] A further beneficial effect of the above is that the heat medium source of the heat exchanger of the present invention is the high-temperature conversion gas obtained in the catalytic cracking conversion process, which makes full use of the residual heat energy, realizes full utilization of energy, and achieves the purpose of energy saving.

[0024] Furthermore, in the above step (3), the methanol catalytic cracking reactor is a tube-in-tube fixed bed reactor, and high-temperature heat transfer oil is installed in the shell side; the catalyst is at least one of a copper-zinc catalyst, an alumina catalyst, a medium-temperature synergistic reaction catalyst, a nickel-based catalyst and an activated carbon catalyst, such as SCST-402 methanol cracking hydrogen production catalyst, M650 methanol cracking hydrogen production catalyst and TCJ-1 methanol cracking hydrogen production catalyst.

[0025] Furthermore, in the above step (3), the temperature of the catalytic cracking conversion is 200-300° C. and the pressure is 0.8-2.5 MPa.

[0026] A further beneficial effect of adopting the above method is that the catalytic cracking conversion treatment of the present invention has the advantages of less side reactions, long service life, high strength, low running resistance, high active components, and high single-pass conversion rate.

[0027] Furthermore, in the above step (5), the washing liquid is circulating methanol; the washing and purification temperature is -30 to -60°C, and the pressure is 4 to 7 MPa.

[0028] The further beneficial effect of adopting the above method is that the present invention can efficiently purify and effectively remove impurities by washing and purifying, and is energy-saving and environmentally friendly. Moreover, the present invention uses production raw materials as washing liquid, and compared with other methods, no other impurities are introduced, and the energy consumption is much lower than that of distillation operation.

[0029] Furthermore, in the above step (6), the pressure swing adsorption tower group is a fixed adsorption bed; and the adsorbent is at least one of activated carbon and 5A molecular sieve.

[0030] Furthermore, in the above step (6), the adsorption temperature is 20-40° C. and the pressure is 0.1-2 MPa.

[0031] A further beneficial effect of adopting the above method is that the adsorption treatment performed by the present invention has a wider application range compared to other operations, and has the characteristics of high efficiency and large adsorption capacity. In addition, the equipment structure of the adsorption tower is compact, the footprint is small, the maintenance cost is low, the operation is safe, and the energy consumption is low.

[0032] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] The equipment of the present invention is safe to operate, has a convenient source of raw materials, is easy to transport and store, has a stable price, a simple process flow, a highly automated equipment, is simple and easy to operate in production, occupies a small area, has low equipment investment costs, has low production costs and a short payback period, fully utilizes surplus heat energy, and has high product quality. The obtained electronic-grade hydrogen meets national standards, has strong stability, can achieve continuous operation, and is adapted to the needs of the high-end market, and has great market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] 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 only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0035] Figure 1 It is a structural schematic diagram of an electronic grade hydrogen production device and a process flow chart of its production method.

[0036] Among them, 1-mixing tank, 2-heat exchanger, 3-vaporizer, 4-methanol catalytic cracking reactor, 5-cooler, 6-purification tower, 7-pressure swing adsorption tower I, 8-pressure swing adsorption tower II, 9-pressure swing adsorption tower III, 10-pressure swing adsorption tower IV, 11-pressure swing adsorption tower V, 12-pressure swing adsorption tower VI. DETAILED DESCRIPTION

[0037] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0038] In the description of the present invention, it is necessary to understand that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0040] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0042] Example 1

[0043] Electronic grade hydrogen production equipment, such as Figure 1 As shown, it includes a mixing tank 1, a heat exchanger 2, a vaporizer 3, a methanol catalytic cracking reactor 4, a cooler 5, a purification tower 6 and a pressure swing adsorption tower group;

[0044] Among them, the mixing tank 1, the heat exchanger 2, the cooler 5, the purification tower 6 and the pressure swing adsorption tower group are connected in sequence;

[0045] The heat exchanger 2, the vaporizer 3, the methanol catalytic cracking reactor 4 and the heat exchanger 2 are cyclically connected;

[0046] The purification tower 6 is connected to the mixing tank 1;

[0047] The pressure swing adsorption tower group consists of 6 towers connected in parallel, including pressure swing adsorption tower I7, pressure swing adsorption tower II8, pressure swing adsorption tower III9, pressure swing adsorption tower IV10, pressure swing adsorption tower V11 and pressure swing adsorption tower VI12.

[0048] Example 2

[0049] The method for producing electronic grade hydrogen adopts the production device of electronic grade hydrogen in Example 1, such as Figure 1 As shown, the specific steps include:

[0050] (1) mixing the methanol solution and desalted water having a salt content of 2 mg / L in a mixing tank 1 at a mass ratio of 1:1 to obtain a mixed solution;

[0051] (2) the mixed liquid is passed into the heat exchanger 2 to perform the first heat exchange with the high-temperature reformed gas obtained in the catalytic cracking reforming process, and then the mixed liquid is heated to 180° C. and passed into the vaporizer 3 to be heated again to 200° C. and vaporized into gas to obtain vaporized gas;

[0052] (3) The vaporized gas is passed into a methanol catalytic cracking reactor 4 filled with a SCST-402 methanol cracking hydrogen production catalyst for catalytic cracking conversion. The methanol catalytic cracking reactor 4 is a tube-in-tube fixed bed reactor, and a high-temperature heat transfer oil is filled in the shell side. The temperature of the catalytic cracking conversion is 200° C. and the pressure is 0.8 MPa, generating a high-temperature conversion gas;

[0053] (4) The high-temperature reformed gas is passed into the heat exchanger 2 to undergo a second heat exchange with the mixed liquid, and then passed into the cooler 5 for cooling to obtain cooled gas;

[0054] (5) The cooling gas is introduced into the purification tower 6 from the bottom of the tower, flowing from bottom to top, and the circulating methanol is introduced into the purification tower 6 from the top of the tower, flowing from top to bottom. The cooling gas and the circulating methanol are in countercurrent contact for washing and purification. The temperature is -33.74°C and the pressure is 5.27 MPa. The washing liquid obtained at the bottom of the tower is introduced into the mixing tank 1 for recycling, and the purified gas is obtained at the top of the tower;

[0055] (6) The purified gas is passed into a pressure swing adsorption tower group filled with activated carbon for adsorption. The pressure swing adsorption tower group is a fixed adsorption bed. The adsorption temperature is 21.56° C. and the pressure is 0.178 MPa. Finally, an electronic grade hydrogen product is obtained at the top of the pressure swing adsorption tower group.

[0056] Example 3

[0057] The method for producing electronic grade hydrogen adopts the production device of electronic grade hydrogen in Example 1, such as Figure 1 As shown, the specific steps include:

[0058] (1) mixing the methanol solution and desalted water having a salt content of 2 mg / L in a mixing tank 1 at a mass ratio of 1.8:1 to obtain a mixed solution;

[0059] (2) the mixed liquid is passed into the heat exchanger 2 to perform the first heat exchange with the high-temperature reformed gas obtained in the catalytic cracking reforming process, and then the mixed liquid is heated to 180° C. and passed into the vaporizer 3 to be heated again to 200° C. and vaporized into gas to obtain vaporized gas;

[0060] (3) The vaporized gas is passed into a methanol catalytic cracking reactor 4 filled with a SCST-402 methanol cracking hydrogen production catalyst for catalytic cracking conversion. The methanol catalytic cracking reactor 4 is a tube-in-tube fixed bed reactor, and a high-temperature heat transfer oil is filled in the shell side. The temperature of the catalytic cracking conversion is 230° C. and the pressure is 2.0 MPa, generating a high-temperature conversion gas;

[0061] (4) The high-temperature reformed gas is passed into the heat exchanger 2 to undergo a second heat exchange with the mixed liquid, and then passed into the cooler 5 for cooling to obtain cooled gas;

[0062] (5) The cooling gas is introduced into the purification tower 6 from the bottom of the tower, flowing from bottom to top, and the circulating methanol is introduced into the purification tower 6 from the top of the tower, flowing from top to bottom. The cooling gas and the circulating methanol are in countercurrent contact for washing and purification. The temperature is -45.27°C and the pressure is 6.73 MPa. The washing liquid obtained at the bottom of the tower is introduced into the mixing tank 1 for recycling, and the purified gas is obtained at the top of the tower;

[0063] (6) The purified gas is passed into a pressure swing adsorption tower group filled with activated carbon for adsorption. The pressure swing adsorption tower group is a fixed adsorption bed. The adsorption temperature is 33.64° C. and the pressure is 0.57 MPa. Finally, an electronic grade hydrogen product is obtained at the top of the pressure swing adsorption tower group.

[0064] Example 4

[0065] The method for producing electronic grade hydrogen adopts the production device of electronic grade hydrogen in Example 1, such as Figure 1 As shown, the specific steps include:

[0066] (1) mixing the methanol solution and the desalted water having a salt content of 2 mg / L in a mixing tank 1 at a mass ratio of 2:1 to obtain a mixed solution;

[0067] (2) the mixed liquid is passed into the heat exchanger 2 to perform the first heat exchange with the high-temperature reformed gas obtained in the catalytic cracking reforming process, and then the mixed liquid is heated to 180° C. and passed into the vaporizer 3 to be heated again to 200° C. and vaporized into gas to obtain vaporized gas;

[0068] (3) The vaporized gas is passed into a methanol catalytic cracking reactor 4 filled with SCST-402 methanol cracking hydrogen production catalyst for catalytic cracking conversion. The methanol catalytic cracking reactor 4 is a tube-in-tube fixed bed reactor with high-temperature heat transfer oil in the shell side. The temperature of the catalytic cracking conversion is 240° C. and the pressure is 2.5 MPa, generating a high-temperature conversion gas;

[0069] (4) The high-temperature reformed gas is passed into the heat exchanger 2 to undergo a second heat exchange with the mixed liquid, and then passed into the cooler 5 for cooling to obtain cooled gas;

[0070] (5) The cooling gas is introduced into the purification tower 6 from the bottom of the tower, flowing from bottom to top, and the circulating methanol is introduced into the purification tower 6 from the top of the tower, flowing from top to bottom. The cooling gas and the circulating methanol are in countercurrent contact for washing and purification. The temperature is -52.78°C and the pressure is 6.99 MPa. The washing liquid obtained at the bottom of the tower is introduced into the mixing tank 1 for recycling, and the purified gas is obtained at the top of the tower;

[0071] (6) The purified gas is passed into a pressure swing adsorption tower group filled with activated carbon for adsorption. The pressure swing adsorption tower group is a fixed adsorption bed. The adsorption temperature is 37.59° C. and the pressure is 1.44 MPa. Finally, an electronic grade hydrogen product is obtained at the top of the pressure swing adsorption tower group.

[0072] Comparative Example

[0073] Example 1 of the Chinese invention patent with application number 202110189451.4 discloses a process for efficiently producing carbon monoxide and hydrogen by cracking methanol, which includes the following five steps:

[0074] (1) Methanol preparation: transporting raw methanol from methanol storage tank 1 to methanol intermediate tank 2;

[0075] (2) Methanol vaporization superheating: The methanol in the methanol intermediate tank 2 is metered and pressurized by the methanol metering pump 3 and then sent to the vaporization superheater 4 through heat exchange. The methanol is heated and converted into a high-temperature gas state and then enters the cracking reactor 5;

[0076] (3) Catalytic reaction: The methanol gas entering the cracking reactor 5 passes through the copper catalyst bed from top to bottom. Under the reaction conditions of temperature 220°C and pressure 0.5 MPa, the methanol is cracked. The main reaction generates high-temperature cracking gas carbon monoxide and hydrogen. At the same time, a side reaction occurs to generate a small amount of wax.

[0077] (4) Cooling and purification: The high-temperature cracked gas, carbon monoxide and hydrogen, discharged from the lower part of the cracking reactor 5 is heat exchanged with the methanol raw material to be introduced into the vaporizing superheater 4 through the heat exchanger 7; the temperature of the cracked gas after the heat exchange is reduced to 119° C., and then enters the water cooler 10 to be further reduced to 43° C.; during the cooling process, the wax generated by the side reaction is condensed into liquid and enters the liquid wax collection tank; the cracked gas is introduced into the gas-liquid separator 13, where the methanol that has not participated in the reaction is removed, and the removed methanol is returned to the vaporizing superheater 4 as a raw material; the cracked gas after the methanol is removed enters the cold dryer 14 for drying, and then enters the cracked gas buffer tank 15;

[0078] (5) Three-stage pressure swing adsorption: The cracked gas from the cracked gas buffer tank 15 is subjected to three-stage pressure swing adsorption to separate high-purity carbon monoxide and hydrogen;

[0079] (6) Utilization of purge gas: The purge gas separated from the three-stage pressure swing adsorption is fully mixed and supplied to the thermal oil furnace 20 as fuel, so that the purge gas resources can be reasonably utilized.

[0080] Performance Testing

[0081] The electronic-grade hydrogen products prepared in Examples 2-4 were taken respectively, and the contents (mass fraction) of hydrogen (H2), nitrogen (N2), oxygen (O2), carbon monoxide (CO), carbon dioxide (CO2), total hydrocarbons (measured as methane), water (H2O) and total impurities were detected, and compared with the comparative examples.

[0082] The results are shown in Table 1.

[0083] Table 1 Content of each component of electronic grade hydrogen products in Examples 2-4

[0084]

[0085] It can be seen from Table 1 that the purity of the electronic-grade hydrogen products of Examples 2-4 of the present invention is all above 99.9996%, which is better than the prior art.

[0086] The above experiments show that the equipment of the present invention is safe to operate, has a convenient source of raw materials, is easy to transport and store, has a stable price, a simple process flow, a highly automated equipment, simple and easy production operation, a small footprint, low equipment investment cost, low production cost and a short payback period, makes full use of waste heat energy, and has high product quality. The obtained electronic-grade hydrogen meets national standards, has strong stability, can achieve continuous operation, and can meet the needs of the high-end market, and has great market application prospects.

[0087] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0088] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A device for producing electronic grade hydrogen, characterized in that: It includes a mixing tank, a heat exchanger, a vaporizer, a methanol catalytic cracking reactor, a cooler, a purification tower and a pressure swing adsorption tower group; The mixing tank, the heat exchanger, the cooler, the purification tower and the pressure swing adsorption tower group are connected in sequence; The heat exchanger, the vaporizer, the methanol catalytic cracking reactor and the heat exchanger are cyclically connected; The purification tower is connected to the mixing tank.

2. The electronic grade hydrogen production device according to claim 1, characterized in that: The pressure swing adsorption tower group consists of 6 towers connected in parallel, including pressure swing adsorption tower I, pressure swing adsorption tower II, pressure swing adsorption tower III, pressure swing adsorption tower IV, pressure swing adsorption tower V and pressure swing adsorption tower VI.

3. A method for producing electronic grade hydrogen, characterized in that: The production device of electronic grade hydrogen as claimed in claim 1 specifically comprises the following steps: (1) mixing methanol solution and desalted water in a mixing tank to obtain a mixed solution; (2) passing the mixed liquid into a heat exchanger to perform a first heat exchange with the high-temperature reformed gas obtained in the catalytic cracking conversion process, and then passing the mixed liquid into a vaporizer after the temperature is increased, and then the temperature is increased again and vaporized into gas to obtain vaporized gas; (3) passing the vaporized gas into a methanol catalytic cracking reactor filled with a catalyst for catalytic cracking conversion to generate a high-temperature conversion gas; (4) passing the high-temperature reformed gas into a heat exchanger to perform a second heat exchange with the mixed liquid, and then passing the high-temperature reformed gas into a cooler for cooling to obtain cooled gas; (5) The cooling gas is introduced into the purification tower from the bottom of the tower, flowing from bottom to top, and the washing liquid is introduced into the purification tower from the top of the tower, flowing from top to bottom. The cooling gas and the washing liquid are in countercurrent contact to perform washing and purification. The washing liquid obtained at the bottom of the tower is introduced into a mixing tank for recycling, and the purified gas is obtained at the top of the tower; (6) The purified gas is passed into a pressure swing adsorption tower group filled with adsorbent for adsorption, and finally an electronic grade hydrogen product is obtained at the top of the pressure swing adsorption tower group.

4. The method for producing electronic grade hydrogen according to claim 3, characterized in that: In step (1), the salt content of the desalted water is 1-5 mg / L; the mass ratio of the methanol solution to the desalted water is (1-2):

1.

5. The method for producing electronic grade hydrogen according to claim 3, characterized in that: In step (2), the temperature is raised to 180° C. and then introduced into a vaporizer, where the temperature is raised again to 200° C. and vaporized into gas.

6. The method for producing electronic grade hydrogen according to claim 3, characterized in that: In step (3), the methanol catalytic cracking reactor is a tubular fixed bed reactor, and high-temperature heat transfer oil is installed in the shell side; the catalyst is at least one of a copper-zinc catalyst, an alumina catalyst, a medium-temperature synergistic reaction catalyst, a nickel-based catalyst and an activated carbon catalyst.

7. The method for producing electronic grade hydrogen according to claim 3, characterized in that: In step (3), the temperature of the catalytic cracking conversion is 200-300° C. and the pressure is 0.8-2.5 MPa.

8. The method for producing electronic grade hydrogen according to claim 3, characterized in that: In step (5), the washing liquid is circulating methanol; the temperature of the washing purification is -30 to -60°C, and the pressure is 4 to 7 MPa.

9. The method for producing electronic grade hydrogen according to claim 3, characterized in that: In step (6), the pressure swing adsorption tower group is a fixed adsorption bed; and the adsorbent is at least one of activated carbon and 5A molecular sieve.

10. The method for producing electronic grade hydrogen according to claim 3, characterized in that: In step (6), the adsorption temperature is 20-40° C. and the pressure is 0.1-2 MPa.

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