Chlor-alkali industry multi-mode hydrogen production and hydrogen chloride synthesis system and method

Abstract

The embodiment of the invention discloses a chlorine-alkali industry multi-mode hydrogen production and hydrogen chloride synthesis system and method.The chlorine-alkali industry multi-mode hydrogen production and hydrogen chloride synthesis system comprises a grid power supply module, a distributed photovoltaic module, a PEM hydrogen production module and a hydrogen chloride synthesis module; the PEM hydrogen production module comprises a PEM electrolytic bath, a cooling device and a heating device; the grid power supply module and the distributed photovoltaic module are connected with the power supply end of the PEM electrolytic cell; the rear end of the PEM electrolytic bath is connected with the first input end of the cooling device; the first output end of the cooling device is connected with the first input end of the heating device, and the first output end of the heating device is connected with the front end of the PEM electrolytic bath; the second input end of the heating device is connected with the distributed photovoltaic module, and the second output end of the heating device outputs hot water; the technical effects of adjusting the working temperature of the PEM electrolytic bath and repeatedly utilizing the high-temperature circulating pure water are achieved, and the energy utilization efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of hydrogen chloride production, and in particular to a multi-mode hydrogen production and hydrogen chloride synthesis system and method for the chlor-alkali industry. Background Art

[0002] The hydrogen source for the hydrogen chloride synthesis process in chlor-alkali enterprises mainly comes from the by-product hydrogen produced by the electrolysis of saturated brine, which is the main hydrogen source for chlor-alkali enterprises. When saturated brine is electrolyzed in an electrolytic cell, the reaction occurs: 2NaCl + 2H2O → 2NaOH + H2↑ + Cl2↑. The generated hydrogen is subjected to refining processes such as cooling, impurity removal, and drying to remove impurities such as water vapor, alkali mist, and metal ions, and then used for hydrogen chloride synthesis. When synthesizing hydrogen chloride, the chlorine-hydrogen ratio is usually controlled at 1:1.05 - 1.10 (volume ratio). In actual production, to ensure that the product does not contain free chlorine, hydrogen is in excess of chlorine by 15% - 20%. The molar ratio of the by-product hydrogen from the electrolysis of saturated brine to chlorine-hydrogen is 1:1, and some chlor-alkali enterprises use the electrolysis of pure water process to supplement the shortage of hydrogen.

[0003] The traditional electrolysis of pure water process usually uses a traditional alkaline electrolytic cell with a certain concentration of KOH solution as the electrolyte. The proton exchange membrane (PEM) electrolytic cell, as an efficient and environmentally friendly hydrogen production device, has been widely used in many fields. However, a large amount of heat is generated during the hydrogen production process of the PEM electrolytic cell. Generally speaking, an increase in temperature will accelerate the reaction rate, reduce the activation overpotential, and improve the efficiency. However, too high a temperature may cause membrane dehydration, increase the ohmic impedance, and even damage the membrane and the catalyst layer. Therefore, it is necessary to control the operating temperature of the PEM electrolytic cell within an ideal range to improve the energy utilization efficiency of the electrolytic hydrogen production system. Summary of the Invention

[0004] By providing a multi-mode hydrogen production and hydrogen chloride synthesis system and method for the chlor-alkali industry in the embodiments of the present application, the problems in the prior art that the working efficiency of the electrolytic cell is low during the hydrogen production process, and the heat generated is not easily dissipated, resulting in membrane dehydration and then damage to the membrane and the catalyst layer are solved. The technical effects of adjusting the working temperature of the PEM electrolytic cell and recycling high-temperature circulating pure water are achieved, and the technical effect of automatically adjusting the temperature of the pure water input into the electrolytic cell is also achieved, improving the energy utilization efficiency.

[0005] In a first aspect, an embodiment of the present invention provides a multi-mode hydrogen production and hydrogen chloride synthesis system for the chlor-alkali industry, including a grid power supply module, a distributed photovoltaic module, a PEM hydrogen production module, and a hydrogen chloride synthesis module; the PEM hydrogen production module includes a PEM electrolyzer, a cooling device, and a heating device; both the grid power supply module and the distributed photovoltaic module are connected to the power supply end of the PEM electrolyzer, and the distributed photovoltaic module is configured to output photovoltaic power; pure water is input at the front end of the PEM electrolyzer, and high-temperature circulating pure water is output at the rear end of the PEM electrolyzer; hydrogen is output at the cathode of the PEM electrolyzer, and oxygen is output at the anode of the PEM electrolyzer; the rear end of the PEM electrolyzer is connected to the first input end of the cooling device; the first output end of the cooling device is connected to the first input end of the heating device, and the first output end of the heating device is connected to the front end of the PEM electrolyzer; the second input end of the heating device is connected to the distributed photovoltaic module, and the second output end of the heating device outputs hot water; the distributed photovoltaic module is configured to heat cold water, and the heating device is configured to use the heat of the distributed photovoltaic module to heat the high-temperature circulating pure water; the cathode of the PEM electrolyzer is connected to the second input end of the cooling device, and the second output end of the cooling device outputs hydrogen; the second output end of the cooling device is connected to the hydrogen chloride synthesis module, which is configured to supply hydrogen to the hydrogen chloride synthesis module.

[0006] In combination with the first aspect, in a possible implementation, the heating device includes a housing and a partition; the partition is disposed in the housing and is slidably connected to the housing; the housing is divided into a hot water area and a high-temperature circulating pure water area by the partition, and by adjusting the position of the partition in the housing, the volumes of the hot water area and the high-temperature circulating pure water area can be adjusted, so that the temperature of the high-temperature circulating pure water can be adjusted.

[0007] In combination with the first aspect, in a possible implementation, it further includes a hydrogen buffer tank and a hydrogen pressure reducing module; the input end of the hydrogen buffer tank is connected to the second output end of the cooling device, the output end of the hydrogen buffer tank is connected to the input end of the hydrogen pressure reducing module; the output end of the hydrogen pressure reducing module is connected to the hydrogen chloride synthesis module.

[0008] In combination with the first aspect, in a possible implementation, the PEM hydrogen production module includes a first water vapor isolation device and a second water vapor isolation device; the first water vapor isolation device is connected between the cathode of the PEM electrolyzer and the cooling device; the anode of the PEM electrolyzer is connected to the third input end of the cooling device, and the third output end of the cooling device outputs oxygen; the second water vapor isolation device is connected between the anode of the PEM electrolyzer and the cooling device.

[0009] In combination with the first aspect, in a possible implementation manner, the PEM hydrogen production module includes a temperature detector and a filter element; a temperature detector is arranged on the side of the high-temperature circulating pure water area close to the PEM electrolyzer; a filter element is arranged between the cooling device and the heating device.

[0010] In combination with the first aspect, in a possible implementation manner, it further includes a transformer and a hydrogen production power supply; the transformer is connected to the grid power supply module; the first input end of the hydrogen production power supply is connected to the transformer, the second input end of the hydrogen production power supply is connected to the distributed photovoltaic module; the hydrogen production power supply is connected to the power supply end of the PEM electrolyzer.

[0011] In combination with the first aspect, in a possible implementation manner, it further includes a pure water preparation module; the front end of the PEM electrolyzer is connected to the pure water preparation module.

[0012] In the second aspect, the embodiment of the present invention provides a method for producing hydrogen and synthesizing hydrogen chloride in a multi-mode chlor-alkali industry, using the chlor-alkali industry multi-mode hydrogen production and hydrogen chloride synthesis system of the first aspect or any possible implementation manner in combination with the first aspect, which is characterized by including the following steps:

[0013] S1: The grid power supply module and the distributed photovoltaic module respectively supply power to the PEM electrolyzer and input pure water to the front end of the PEM electrolyzer.

[0014] S2: Hydrogen is generated at the cathode of the PEM electrolyzer, and after passing through the water vapor isolation device and the cooling device, it is collected through the hydrogen buffer tank. The collected hydrogen is input into the hydrogen chloride synthesis device to synthesize hydrogen chloride after passing through the pressure reducing device.

[0015] S3: When it is detected that the temperature in the PEM electrolyzer is too high, high-temperature circulating pure water is output from the rear end of the PEM electrolyzer. After the high-temperature circulating pure water is cooled, it is heated by the heating device and then input from the front end of the PEM electrolyzer. Among them, the heating device can automatically adjust the temperature of the output high-temperature circulating pure water.

[0016] In combination with the second aspect, in a possible implementation manner, the step S1 includes: a pure off-grid hydrogen production mode, adjusting the hydrogen production power of the electrolyzer according to the power of the distributed photovoltaic module, and only using the distributed photovoltaic module to supply power to the PEM electrolyzer; a grid-connected hydrogen production mode, collecting the power generation power of the distributed photovoltaic module in real time, and the insufficient part is supplemented by the grid power supply module and then the two supply power to the PEM electrolyzer at the same time; a grid power constant power hydrogen production mode, cutting off the power supply of the distributed photovoltaic module, and only supplying power to the PEM electrolyzer through the grid power supply module.

[0017] Combined with the first aspect, in a possible implementation, in step S3, the deviation between the temperature of the high-temperature circulating pure water output by the heating device and the target temperature can be adjusted by adjusting the partition board, and the specific method is as follows:

[0018] The deviation between the output temperature of the high-temperature circulating pure water and the target temperature is:

[0019] ΔT = T out - T0;

[0020] where, T out is the temperature of the high-temperature circulating pure water at the outlet of the heating device, and T0 is the target temperature of the high-temperature circulating pure water.

[0021] At steady state, the heat absorption and heat dissipation in the high-temperature circulating pure water area are balanced, that is:

[0022]

[0023] where, A is the effective area of the partition board, k is the comprehensive heat transfer coefficient, x is the current position of the partition board, l is the effective length of the heating device, and Q in is the thermal power of the hot water input by the photovoltaic.

[0024] From the steady-state balance equation, it can be obtained that:

[0025]

[0026] When the detected deviation temperature ΔT > 0 (i.e., T out > T0), it is necessary to adjust the position x of the partition board to lower the temperature. Differentiate ΔT with respect to x to obtain the sensitivity relationship:

[0027]

[0028] Therefore, the proportional relationship between the partition board movement amount Δx and the temperature deviation ΔT can be approximated as:

[0029] Δx = -K p ·ΔT;

[0030] where, K P is the proportionality coefficient.

[0031] One or more technical solutions provided by this application have at least the following technical effects:

[0032] An embodiment of the present invention adopts a multi-mode hydrogen production and hydrogen chloride synthesis system and method for the chlor-alkali industry, including a grid power supply module, a distributed photovoltaic module, a PEM hydrogen production module, and a hydrogen chloride synthesis module; the PEM hydrogen production module includes a PEM electrolyzer, a cooling device, and a heating device; both the grid power supply module and the distributed photovoltaic module are connected to the power supply end of the PEM electrolyzer, and the distributed photovoltaic module is configured to output photovoltaic power; both the grid power supply module and the distributed photovoltaic module can provide electrical energy for the operation of the PEM electrolyzer; pure water is input at the front end of the PEM electrolyzer, and high-temperature circulating pure water is output at the rear end of the PEM electrolyzer; the front end of the PEM electrolyzer is the feed end, and after pure water is input, an electrolysis reaction can occur to generate hydrogen and oxygen; that is, hydrogen is output at the cathode of the PEM electrolyzer, and oxygen is output at the anode of the PEM electrolyzer; the rear end of the PEM electrolyzer is connected to the first input end of the cooling device; the first output end of the cooling device is connected to the first input end of the heating device, and the first output end of the heating device is connected to the front end of the PEM electrolyzer; a large amount of heat is generated during the hydrogen production process of the PEM electrolyzer, so cooling treatment is required. The PEM electrolyzer mainly relies on its own cooling device and pure water for cooling treatment, and there are also certain requirements for the temperature of the pure water input into the PEM electrolyzer. Therefore, when the PEM electrolyzer detects that the internal working temperature is too high, it can output the unreacted high-temperature circulating pure water in the PEM electrolyzer for cooling, and then add pure water at an appropriate temperature to the electrolyzer to maintain its operation. The high-temperature circulating pure water output from the PEM electrolyzer is cooled by the cooling device. After cooling, there is also a certain energy loss in the high-temperature circulating pure water after passing through a section of pipeline. After the temperature of the high-temperature circulating pure water is heated to the target temperature by the heating device, it is then input into the PEM electrolyzer for reaction, so as to achieve the technical effect of recycling the high-temperature circulating pure water and keep the temperature of the pure water input into the PEM electrolyzer within a stable range. The second input end of the heating device is connected to the distributed photovoltaic module, and the second output end of the heating device outputs hot water; the distributed photovoltaic module is configured to heat cold water, and the heating device is configured to use the heat of the distributed photovoltaic module to heat the high-temperature circulating pure water; the distributed photovoltaic module can not only provide photovoltaic power for the operation of the PEM electrolyzer, but also use the heat of the distributed photovoltaic module to heat the high-temperature circulating pure water; the cathode of the PEM electrolyzer is connected to the second input end of the cooling device, and the second output end of the cooling device outputs hydrogen; the second output end of the cooling device is connected to the hydrogen chloride synthesis module, and it is configured to provide hydrogen for the hydrogen chloride synthesis module. The hydrogen is cooled and then input into the hydrogen chloride synthesis module for synthesizing hydrogen chloride.This application solves the problems in the prior art that during the process of hydrogen production in an electrolytic cell, the working efficiency is low, and the heat generated is not easily dissipated, resulting in membrane dehydration and then damage to the membrane and the catalyst layer. It achieves the technical effects of regulating the working temperature of the PEM electrolytic cell and reusing the high-temperature circulating pure water, and also realizes the technical effect of automatically regulating the temperature of the pure water input into the electrolytic cell, improving the energy utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of this application. Obviously, the drawings in the following description are some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0034] Figure 1 It is a schematic diagram of a multi-mode hydrogen production and hydrogen chloride synthesis system for the chlor-alkali industry provided by an embodiment of this application;

[0035] Figure 2 It is a schematic diagram of a PEM hydrogen production module provided by an embodiment of this application;

[0036] Figure 3 It is a schematic diagram of a heating device provided by an embodiment of this application;

[0037] Figure 4 It is a flowchart of a multi-mode hydrogen production and hydrogen chloride synthesis method for the chlor-alkali industry provided by an embodiment of this application.

[0038] Reference numerals: 1 - grid power supply module; 2 - distributed photovoltaic module; 3 - PEM hydrogen production module; 31 - PEM electrolytic cell; 32 - cooling device; 33 - heating device; 331 - housing; 332 - partition; 34 - first water vapor isolation device; 35 - second water vapor isolation device; 36 - temperature detection element; 37 - filter element; 38 - first flowmeter; 39 - second flowmeter; 4 - hydrogen chloride synthesis module; 5 - hydrogen buffer tank; 6 - hydrogen pressure reduction module; 7 - transformer; 8 - hydrogen production power supply; 9 - pure water preparation module; 91 - pure water tank; 10 - gas storage tank. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] The following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

[0040] In the description of the embodiments of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application 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. Therefore, it should not be construed as a limitation to the present application. The terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. In addition, the terms "installation", "connection", and "connection" 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0041] During the electrolysis reaction of the PEM electrolyzer 31, controlling the operating temperature of the PEM electrolyzer 31 within the ideal range can improve the energy utilization efficiency of the electrolytic hydrogen production system. Most studies show that the PEM electrolyzer 31 has the highest comprehensive energy efficiency at 70-80 °C (hydrogen production efficiency is about 75%-85%). Specifically, the high-temperature circulating pure water in the PEM mainly relies on the proton exchange membrane, and the working temperature will affect the reaction kinetics, the conductivity of the membrane, and the durability of the materials. Generally speaking, an increase in temperature will accelerate the reaction rate, reduce the activation overpotential, and improve the efficiency. However, too high a temperature may cause membrane dehydration, increase the ohmic impedance, and even damage the membrane and the catalyst layer. Therefore, it is necessary to provide a device for maintaining the temperature of the high-temperature circulating pure water in the PEM electrolyzer 31, which can improve the working efficiency of the PEM electrolyzer 31 and extend the service life of the PEM electrolyzer 31.

[0042] The embodiments of the present invention provide a multi-mode hydrogen production and hydrogen chloride synthesis system for the chlor-alkali industry, as Figures 1-3As shown in the figure, it includes a grid power supply module 1, a distributed photovoltaic module 2, a PEM hydrogen production module 3, and a hydrogen chloride synthesis module 4; the PEM hydrogen production module 3 includes a PEM electrolyzer 31, a cooling device 32, and a heating device 33; both the grid power supply module 1 and the distributed photovoltaic module 2 are connected to the power supply end of the PEM electrolyzer 31, and the distributed photovoltaic module 2 is configured to output photovoltaic power; pure water is input at the front end of the PEM electrolyzer 31, and high-temperature circulating pure water is output at the rear end of the PEM electrolyzer 31; hydrogen is output from the cathode of the PEM electrolyzer 31, and oxygen is output from the anode of the PEM electrolyzer 31; the rear end of the PEM electrolyzer 31 is connected to the first input end of the cooling device 32; the first output end of the cooling device 32 is connected to the first input end of the heating device 33, and the first output end of the heating device 33 is connected to the front end of the PEM electrolyzer 31; the second input end of the heating device 33 is connected to the distributed photovoltaic module 2, and hot water is output from the second output end of the heating device 33; the distributed photovoltaic module 2 is configured to heat cold water, and the heating device 33 is configured to use the heat of the distributed photovoltaic module 2 to heat high-temperature circulating pure water; the cathode of the PEM electrolyzer 31 is connected to the second input end of the cooling device 32, and hydrogen is output from the second output end of the cooling device 32; the second output end of the cooling device 32 is connected to the hydrogen chloride synthesis module 4, which is configured to supply hydrogen to the hydrogen chloride synthesis module 4.

[0043] Exemplarily, a chlor-alkali enterprise is equipped with a distributed photovoltaic module 2, and the direct current generated by it can supply power to the PEM electrolyzer 31. In this application, hydrogen is produced by combining the grid power supply module 1 and the distributed photovoltaic module 2 as two power supply sources. When the photovoltaic power generation is sufficient during the day, all photovoltaic power is used for hydrogen production; in case of insufficient photovoltaic power generation such as rainy days, the photovoltaic power is preferentially used for power supply, and the insufficient power is supplemented by the grid power supply module 1 for hydrogen production; under the condition of no light at night, the grid power supply module 1 is used for power supply to produce hydrogen. This cooperation method improves the utilization efficiency of photovoltaic power and reduces the operating cost of hydrogen production.

[0044] Exemplarily, a large amount of heat is generated during the hydrogen production process of the PEM electrolyzer 31, so cooling treatment is required. The PEM electrolyzer 31 mainly relies on its own cooling device and pure water for cooling treatment, and there are also certain requirements for the temperature of the pure water input into the PEM electrolyzer 31. Therefore, when the PEM electrolyzer 31 detects that the internal working temperature is too high, it can output the unreacted high-temperature circulating pure water in the PEM electrolyzer 31 for cooling, and then add pure water at an appropriate temperature into the electrolyzer to maintain its operation. The high-temperature circulating pure water output from the PEM electrolyzer 31 is cooled by the cooling device 32. After cooling, there is also a certain amount of energy loss in the high-temperature circulating pure water after passing through a section of pipeline. After the temperature of the high-temperature circulating pure water is heated to the target temperature by the heating device 33, it is then input into the PEM electrolyzer 31 for reaction, thereby achieving the technical effect of reusing the high-temperature circulating pure water and maintaining the temperature of the pure water input into the PEM electrolyzer 31 within a stable range.

[0045] Exemplarily, the distributed photovoltaic module 2 can not only provide photovoltaic power for the operation of the PEM electrolyzer 31, but also use the heat of the distributed photovoltaic module 2 to heat the high-temperature circulating pure water, thereby improving the energy utilization efficiency.

[0046] In the embodiment of the present application, as Figures 1-3 shown, the heating device 33 includes a housing 331 and a partition 332; the partition 332 is arranged in the housing 331 and is slidably connected to the housing 331; the housing 331 is divided into a hot water area and a high-temperature circulating pure water area by the partition 332. By adjusting the position of the partition 332 in the housing 331, the volumes of the hot water area and the high-temperature circulating pure water area can be adjusted, so as to adjust the temperature of the high-temperature circulating pure water.

[0047] Exemplarily, the partition is driven to slide in the housing by a linear motor.

[0048] Exemplarily, after the PEM electrolyzer 31 has been operating for a period of time, the temperature of the high-temperature circulating pure water therein rises and does not meet the target temperature T0 of the PEM electrolyzer 31, and cooling treatment is required. Specifically, the temperature of the high-temperature circulating pure water output by the PEM electrolyzer 31 is T1. After being cooled by the cooling device to a certain temperature, it is then heated to the target temperature T0 by the heating device 33. The heating device 33 is divided into two regions. One region is the hot water area, and the other region is the high-temperature circulating pure water area. The hot water area and the high-temperature circulating pure water area are separated by a partition 332. The partition 332 can slide on the outer shell 331 of the heating device 33, so as to be able to adjust the areas of the two regions. A temperature detection component 36 is provided at the output end of the high-temperature circulating pure water area. The temperature detection component 36 includes a thermometer. When the thermometer detects that the temperature at the output end of the high-temperature circulating pure water is relatively high, the position of the partition 332 needs to be adjusted, so that the volume of the hot water area is smaller and the area of the high-temperature circulating pure water area is larger, so as to achieve the technical effect of reducing the temperature of the high-temperature circulating pure water and maintaining it within the range of T0 and recycling it.

[0049] Exemplarily, the heating device 33 has a cubic structure. The effective length of the heating device 33 is l. The hot water area contains hot water, and the heat of the hot water comes from the photovoltaic panel.

[0050] Specifically, the deviation between the output temperature of the high-temperature circulating pure water and the target temperature is:

[0051] ΔT = T out - T0;

[0052] where, T out is the temperature of the high-temperature circulating pure water at the outlet of the heating device 33, and T0 is the target temperature of the high-temperature circulating pure water.

[0053] The temperature change of the high-temperature circulating pure water area is mainly determined by the following factors:

[0054] Heat transfer in the hot water area: Through the heat conduction of the partition 332, the heat transfer rate is positively correlated with the volume of the hot water area (area A × x); Heat dissipation in the high-temperature circulating pure water area: The heat dissipation rate is positively correlated with the volume of the high-temperature circulating pure water area (area A × (l - x)).

[0055] At steady state, the heat absorption and heat dissipation in the high-temperature circulating pure water area are balanced, that is:

[0056]

[0057] where, A is the effective area of the partition 332 (m 2 ), k is the comprehensive heat transfer coefficient (W / (m 2 ·℃)); x is the current position of the partition 332 (defining the left side of the partition 332 as the hot water area and the right side as the high-temperature circulating pure water area, 0 ≤ x ≤ l), Q inis the thermal power of the photovoltaic input hot water;

[0058] Derivation of the relationship between the deviation temperature and the displacement of the partition plate 332:

[0059] From the steady-state balance equation, it can be obtained that:

[0060]

[0061] When the detected deviation temperature ΔT>0 (i.e., T out >T0), it is necessary to reduce the temperature by adjusting the position x of the partition plate 332. Differentiating ΔT with respect to x gives the sensitivity relationship:

[0062]

[0063] Therefore, the proportional relationship between the displacement Δx of the partition plate 332 and the temperature deviation ΔT can be approximated as:

[0064] Δx = -K p ·ΔT;

[0065] where K P is the proportionality coefficient (m / ℃), and the negative sign indicates that when the temperature is too high, the volume of the hot water area needs to be reduced (the partition plate moves to the left).

[0066] In the embodiment of the present application, as Figures 1-3 shown, it further includes a hydrogen buffer tank 5 and a hydrogen pressure reduction module 6; the input end of the hydrogen buffer tank 5 is connected to the second output end of the cooling device 32, the output end of the hydrogen buffer tank 5 is connected to the input end of the hydrogen pressure reduction module 6; the output end of the hydrogen pressure reduction module 6 is connected to the hydrogen chloride synthesis module 4.

[0067] Exemplarily, hydrogen enters the first water-vapor isolation device 34 for water-vapor separation, and the separated hydrogen enters the cooling device 32 for cooling. The purity of the cooled hydrogen is greater than 99.9%, and the cooled hydrogen is transported to the hydrogen buffer tank 5. The pressure range of the buffer tank is 0.3 - 2.8 MPa, and the volume is 49.3 m3. After buffering, the hydrogen pressure is reduced to a slightly positive pressure state (≤3.8 kPa). Finally, this high-purity hydrogen is safely and stably transported into the existing hydrogen gas cabinet for subsequent hydrogen chloride synthesis.

[0068] In the embodiment of the present application, as Figures 1-3 shown, the PEM hydrogen production module 3 includes a first water-vapor isolation device 34 and a second water-vapor isolation device 35; a first water-vapor isolation device 34 is connected between the cathode of the PEM electrolyzer 31 and the cooling device 32; the anode of the PEM electrolyzer 31 is connected to the third input end of the cooling device 32, and oxygen is output from the third output end of the cooling device 32; a second water-vapor isolation device 35 is connected between the anode of the PEM electrolyzer 31 and the cooling device 32.

[0069] In the embodiments of the present application, as Figures 1-3 shown, the PEM hydrogen production module 3 includes a temperature detection component 36 and a filtering component 37; a temperature detection component 36 is provided on one side of the high-temperature circulating pure water area close to the PEM electrolyzer 31; a filtering component 37 is provided between the cooling device 32 and the heating device 33.

[0070] Exemplarily, the filtering component 37 can filter impurities in the high-temperature circulating pure water.

[0071] Exemplarily, the PEM hydrogen production module 3 further includes a first flowmeter 38 and a second flowmeter 39. The output end of the first water-vapor isolation device 34 is connected to the first flowmeter 38, which can detect the flow rate of hydrogen output by the PEM electrolyzer 31; the output end of the second water-vapor isolation device 35 is connected to the second flowmeter 39, which can detect the flow rate of oxygen output by the PEM electrolyzer 31.

[0072] In the embodiments of the present application, as Figures 1-3 shown, it further includes a transformer 7 and a hydrogen production power supply 8; the transformer 7 is connected to the grid power supply module 1; the first input end of the hydrogen production power supply 8 is connected to the transformer 7, and the second input end of the hydrogen production power supply 8 is connected to the distributed photovoltaic module 2; the hydrogen production power supply 8 is connected to the power supply end of the PEM electrolyzer 31.

[0073] Exemplarily, an AC / DC power module and a DC / DC power module are provided in the hydrogen production power supply 8. The distributed photovoltaic module 2 is connected to the DC / DC power module, and the grid power supply module 1 is connected to the AC / DC power module.

[0074] In the embodiments of the present application, as Figures 1-3 shown, it further includes a pure water preparation module 9; the front end of the PEM electrolyzer 31 is connected to the pure water preparation module 9.

[0075] Exemplarily, pure water can adopt pure water preparation processes such as "ultrafiltration + reverse osmosis dual membrane method", and it is required to meet the pure water conductivity ≤ 0.1 us / cm.

[0076] Exemplarily, the pure water preparation module 9 includes a pure water tank 91 and an oxygen separation tank. Pure water is contained in the pure water tank 91. The output end of the pure water tank 91 is connected to the input end of the oxygen separation tank, and the output end of the oxygen separation tank is connected to the PEM electrolyzer 31. The pure water in the pure water tank 91 is pumped into the oxygen separation tank. In the oxygen separation tank, the pure water is pumped into the electrolyzer for electrolysis reaction through a pump. The water in the electrolyzer is decomposed into hydrogen and oxygen. The generated oxygen and a small amount of water are separated in the second water-vapor isolation device 35. The separated pure water returns to the oxygen separation tank, and the oxygen is cooled by the cooling device 32 and then transported to the gas storage tank 10 for collection or directly discharged.

[0077] An embodiment of the present invention provides a method for synthesizing hydrogen chloride by multi-mode hydrogen production in the chlor-alkali industry, as follows Figure 4 As shown, a multi-mode hydrogen production and hydrogen chloride synthesis system for the chlor-alkali industry is used, and its steps include: S1: The grid power supply module 1 and the distributed photovoltaic module 2 respectively supply power to the PEM electrolyzer 31 and input pure water to the front end of the PEM electrolyzer 31.

[0078] S2: Hydrogen is generated at the cathode of the PEM electrolyzer 31, and after passing through the water vapor isolation device and the cooling device 32, it is collected through the hydrogen buffer tank 5. The collected hydrogen is input into the hydrogen chloride synthesis device to synthesize hydrogen chloride after passing through the pressure reducing device.

[0079] S3: When it is detected that the temperature in the PEM electrolyzer 31 is too high, high-temperature circulating pure water is output from the rear end of the PEM electrolyzer 31. The high-temperature circulating pure water is cooled and then heated by the heating device 33 and input from the front end of the PEM electrolyzer 31. Among them, the heating device 33 can automatically adjust the temperature of the output high-temperature circulating pure water.

[0080] In the embodiment of the present application, as follows Figure 4 As shown, step S1 includes: a pure off-grid hydrogen production mode, adjusting the hydrogen production power of the electrolyzer according to the power of the distributed photovoltaic module 2, and only using the distributed photovoltaic module 2 to supply power to the PEM electrolyzer 31; a grid-connected hydrogen production mode, real-time collecting the power generation power of the distributed photovoltaic module 2, and the insufficient part is supplemented by the grid power supply module 1 and then supply power to the PEM electrolyzer 31 at the same time; a grid power constant power hydrogen production mode, cutting off the power supply of the distributed photovoltaic module 2, and only supplying power to the PEM electrolyzer 31 through the grid power supply module 1.

[0081] Exemplarily, the AC / DC power module operates in the off-grid mode. By controlling the DC / DC power module, the hydrogen production power of the PEM electrolyzer 31 is adjusted in real time according to the power of the distributed photovoltaic module 2. After the system automatically judges that the start-up power is reached, power is supplied to the PEM cell through the DC / DC power supply, thereby realizing the pure off-grid hydrogen production mode.

[0082] Exemplarily, the AC / DC power module operates in the grid-connected hydrogen production mode, real-time collecting the power generation power of the distributed photovoltaic module 2, controlled by the system, issuing an instruction to the AC / DC power module, and outputting electric energy through the grid power supply module 1 to supply power to the PEM cell, realizing the function of simultaneously supplying power to the PEM electrolyzer 31 by the distributed photovoltaic module 2 and the grid power supply module 1. The system power tracking accuracy is not greater than 500 milliseconds.

[0083] Exemplarily, if there are special situations such as photovoltaic panel failures or inspections and repairs, the power supply of the distributed photovoltaic module 2 is cut off, and only the grid power supply module 1 supplies power to the PEM electrolyzer 31. The grid power constant power hydrogen production mode is realized.

[0084] In the embodiment of the present application, as Figure 3 and Figure 4 shown, in step S3, the deviation between the temperature of the high-temperature circulating pure water output by the heating device 33 and the target temperature can be adjusted by adjusting the partition plate 332, which is specifically as follows:

[0085] The deviation between the output temperature of the high-temperature circulating pure water and the target temperature is:

[0086] ΔT = T out - T0;

[0087] wherein, T out is the temperature of the high-temperature circulating pure water at the outlet of the heating device 33, and T0 is the target temperature of the high-temperature circulating pure water.

[0088] At steady state, the heat absorption and heat dissipation in the high-temperature circulating pure water area are balanced, that is:

[0089]

[0090] wherein, A is the effective area of the partition plate 332, k is the comprehensive heat transfer coefficient, x is the current position of the partition plate 332, l is the effective length of the heating device 33, Q in is the thermal power of the hot water input by the photovoltaic;

[0091] From the steady-state balance equation, it can be obtained that:

[0092]

[0093] When the detected deviation temperature ΔT > 0 (i.e., T out > T0), it is necessary to reduce the temperature by adjusting the position x of the partition plate 332. Differentiating ΔT with respect to x, the sensitivity relationship is obtained:

[0094]

[0095] Therefore, the proportional relationship between the movement amount Δx of the partition plate 332 and the temperature deviation ΔT can be approximated as:

[0096] Δx = -K p ·ΔT;

[0097] wherein, K P is the proportionality coefficient.

[0098] Exemplarily, Q in is the thermal power of the hot water input by the photovoltaic, and its definition is:

[0099] Q in = η·P pv = η·(V pv ·I pv );

[0100] Among them, η is the efficiency of converting photovoltaic electric energy into heat energy, and P pv is the electric power output by the photovoltaic panel (W), which is determined by the photovoltaic voltage V pv and the current I pv ;

[0101] It should be noted that Q in is the thermal power converted from photovoltaic electric energy in the hot water area, which is used to heat the high-temperature circulating pure water area and compensate for the heat dissipation loss, so as to maintain the target temperature T0.

[0102] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, reference can be made to each other. The key points of each embodiment are the differences from other embodiments.

[0103] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting the present application; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the present application.

Claims

1. A multi-mode hydrogen production and hydrogen chloride synthesis system for the chlor-alkali industry, characterized in that, It includes a grid power supply module (1), a distributed photovoltaic module (2), a PEM hydrogen production module (3), and a hydrogen chloride synthesis module (4); The PEM hydrogen production module (3) includes a PEM electrolyzer (31), a cooling device (32), and a heating device (33); Both the grid power supply module (1) and the distributed photovoltaic module (2) are connected to the power supply end of the PEM electrolyzer (31), and the distributed photovoltaic module (2) is configured to output photovoltaic power; Pure water is input at the front end of the PEM electrolyzer (31), and high-temperature circulating pure water is output at the rear end of the PEM electrolyzer (31); Hydrogen is output from the cathode of the PEM electrolyzer (31), and oxygen is output from the anode of the PEM electrolyzer (31); The rear end of the PEM electrolyzer (31) is connected to the first input end of the cooling device (32); the first output end of the cooling device (32) is connected to the first input end of the heating device (33), and the first output end of the heating device (33) is connected to the front end of the PEM electrolyzer (31); The second input end of the heating device (33) is connected to the distributed photovoltaic module (2), and the second output end of the heating device (33) outputs hot water; The distributed photovoltaic module (2) is configured to heat cold water, and the heating device (33) is configured to use the heat of the distributed photovoltaic module (2) to heat the high-temperature circulating pure water; The cathode of the PEM electrolyzer (31) is connected to the second input end of the cooling device (32), and hydrogen is output from the second output end of the cooling device (32); The second output end of the cooling device (32) is connected to the hydrogen chloride synthesis module (4), and it is configured to supply hydrogen to the hydrogen chloride synthesis module (4).

2. The hydrogen production and hydrogen chloride synthesis system for chlor-alkali industry with multiple modes according to claim 1, wherein, The heating device (33) includes a housing (331) and a partition (332); The partition (332) is arranged inside the housing (331) and is slidably connected to the housing (331); The housing (331) is divided into a hot water area and a high-temperature circulating pure water area by the partition (332). By adjusting the position of the partition (332) inside the housing (331), the volumes of the hot water area and the high-temperature circulating pure water area can be adjusted, so that the temperature of the high-temperature circulating pure water can be adjusted.

3. The hydrogen production and hydrogen chloride synthesis system for chlor-alkali industry according to claim 1, characterized in that It further includes a hydrogen buffer tank (5) and a hydrogen pressure reduction module (6); The input end of the hydrogen buffer tank (5) is connected to the second output end of the cooling device (32), and the output end of the hydrogen buffer tank (5) is connected to the input end of the hydrogen pressure reduction module (6); The output end of the hydrogen pressure reduction module (6) is connected to the hydrogen chloride synthesis module (4).

4. The hydrogen production and hydrogen chloride synthesis system for chlor-alkali industry according to claim 1, characterized in that, The PEM hydrogen production module (3) includes a first water vapor isolation device (34) and a second water vapor isolation device (35); The first water vapor isolation device (34) is connected between the cathode of the PEM electrolyzer (31) and the cooling device (32); The anode of the PEM electrolyzer (31) is connected to the third input end of the cooling device (32), and oxygen is output from the third output end of the cooling device (32). A second water vapor isolation device (35) is connected between the anode of the PEM electrolyzer (31) and the cooling device (32).

5. The hydrogen production and hydrogen chloride synthesis system for chlor-alkali industry according to claim 2, characterized in that, The PEM hydrogen production module (3) includes a temperature detector (36) and a filter (37). A temperature detector (36) is arranged on one side of the high-temperature circulating pure water area close to the PEM electrolyzer (31). A filter (37) is arranged between the cooling device (32) and the heating device (33).

6. The hydrogen production and hydrogen chloride synthesis system for the chlor-alkali industry according to claim 1, wherein, It further includes a transformer (7) and a hydrogen production power supply (8). The transformer (7) is connected to the grid power supply module (1). The first input end of the hydrogen production power supply (8) is connected to the transformer (7), and the second input end of the hydrogen production power supply (8) is connected to the distributed photovoltaic module (2). The hydrogen production power supply (8) is connected to the power supply end of the PEM electrolyzer (31).

7. The hydrogen production and hydrogen chloride synthesis system for chlor-alkali industry with multiple modes according to claim 1, characterized in that It further includes a pure water preparation module (9). The front end of the PEM electrolyzer (31) is connected to the pure water preparation module (9).

8. A method for producing hydrogen and synthesizing hydrogen chloride in a multi-mode in the chlor-alkali industry, using the chlor-alkali industry multi-mode hydrogen production and hydrogen chloride synthesis system as claimed in claims 1-7, characterized in that, It includes the following steps: S1: The grid power supply module (1) and the distributed photovoltaic module (2) respectively supply power to the PEM electrolyzer (31), and pure water is input to the front end of the PEM electrolyzer (31). S2: Hydrogen is generated at the cathode of the PEM electrolyzer (31), and after passing through the water vapor isolation device and the cooling device (32), it is collected by the hydrogen buffer tank (5), and the collected hydrogen is input to the hydrogen chloride synthesis device to synthesize hydrogen chloride after passing through the pressure reducing device. S3: When it is detected that the temperature in the PEM electrolyzer (31) is too high, high-temperature circulating pure water is output from the rear end of the PEM electrolyzer (31), and after being cooled, it is heated by the heating device (33) and then input from the front end of the PEM electrolyzer (31), wherein the heating device (33) can automatically adjust the temperature of the output high-temperature circulating pure water.

9. The method for producing hydrogen chloride by multi-mode hydrogen production and synthesizing hydrogen chloride in the chlor-alkali industry according to claim 8, characterized in that, The step S1 includes: Pure off-grid hydrogen production mode, adjusting the hydrogen production power of the electrolyzer according to the power of the distributed photovoltaic module (2), and only using the distributed photovoltaic module (2) to supply power to the PEM electrolyzer (31). Grid-connected hydrogen production mode, real-time collecting the power generation power of the distributed photovoltaic module (2), and the insufficient part is supplemented by the grid power supply module (1) and then supply power to the PEM electrolyzer (31) simultaneously. Grid power constant power hydrogen production mode, cutting off the power supply of the distributed photovoltaic module (2), and only using the grid power supply module (1) to supply power to the PEM electrolyzer (31).

10. The method for producing hydrogen chloride by multi-mode hydrogen production in the chlor-alkali industry according to claim 8, characterized in that, In the step S3, the deviation between the temperature of the high-temperature circulating pure water output by the heating device (33) and the target temperature can be adjusted by adjusting the partition plate (332), and the specific method is as follows: The deviation between the output temperature of the high-temperature circulating pure water and the target temperature is: ΔT = T out - T0; Among them, T out is the temperature of the high-temperature circulating pure water at the outlet of the heating device (33), and T0 is the target temperature of the high-temperature circulating pure water. In the steady state, the heat absorption and heat dissipation of the high-temperature circulating pure water area are balanced, that is: Among them, A is the effective area of the partition (332), k is the comprehensive heat transfer coefficient, x is the current position of the partition (332), l is the effective length of the heating device (33), and Q in is the thermal power of the photovoltaic input hot water; From the steady-state balance equation, it can be obtained that: When the deviation temperature ΔT > 0 (i.e., T out > T0) is detected, the temperature needs to be reduced by adjusting the position x of the partition plate (332). Differentiating ΔT with respect to x gives the sensitivity relationship: Therefore, the proportional relationship between the moving amount Δx of the partition plate (332) and the temperature deviation ΔT can be approximated as: Δx = -K p ·ΔT; Among them, K P is the proportionality coefficient.

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