Process method for hydrogen production based on electrolysis of seawater with pulse and negative resin

Abstract

The application provides a kind of electrolytic seawater hydrogen production process method based on pulse and negative resin, belongs to hydrogen production technical field. To solve the problems of high cost, difficult to be applied in large scale, low hydrogen production efficiency, restricted by region, high reaction temperature, intense side reaction and difficult to guarantee safety in existing hydrogen production methods. The seawater is injected into ion exchange column containing anion resin to remove chlorine, and the micro-chlorine seawater is injected into electrolytic device for pulse electrolysis to obtain hydrogen and electrolyte rich in sulfate. The electrolyte is treated and then injected into ion exchange column to regenerate the saturated anion resin in situ. It can be widely used and has strong repeatability, increases the regulation space of electrocatalytic system, reduces production cost and energy consumption, effectively solves the problem of secondary pollution caused by chlorine gas generated in the electrolysis process; reduces the fouling rate of electrode surface; the electrolyte can be used for regeneration of saturated anion exchange resin, which realizes the recycling of resources.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogen production, in particular to a process for electrolyzing seawater to produce hydrogen based on pulse and negative resin. BACKGROUND

[0002] With the deepening of the energy revolution, China's energy supply and demand structure needs to be further transformed towards clean and low carbon. Hydrogen energy, as a clean secondary energy source, has the advantages of zero carbon emission and zero pollution, and is an important starting point for promoting large-scale utilization of renewable energy. At present, China's annual hydrogen production is about 3500*10 4 t, of which more than 80% is produced by fossil fuels, which dominates. Using fossil fuels to produce hydrogen not only consumes limited fossil energy, but also causes a series of problems such as carbon emissions. Therefore, clean and efficient green hydrogen production technology has become a trend.

[0003] There are five main types of existing green hydrogen production technologies: water electrolysis hydrogen production technology (CN218893742U), solar water splitting hydrogen production technology (CN109642333B), biomass hydrogen production technology (CN113942976B), nuclear energy hydrogen production technology (CN212293761U) and seawater hydrogen production technology (CN114351169B). Among them, the water electrolysis hydrogen production technology has the disadvantages of large consumption of fresh water resources, low equipment life, high energy consumption, etc., and is difficult to be applied on a large scale; the solar water splitting hydrogen production technology has the problems of low hydrogen production efficiency, time and regional influence, etc.; the biomass hydrogen production technology has the problems of high hydrogen production cost and low hydrogen content in mixed products; the nuclear energy hydrogen production technology has the disadvantages of high reaction temperature and immature technology, which is difficult to be applied in practice; the seawater hydrogen production has the problems of complex seawater composition and violent side reactions, which limit its practical application. SUMMARY

[0004] The technical problem to be solved by the present application is:

[0005] In order to solve the problems of high cost, difficult to be applied on a large scale, low hydrogen production efficiency, regional restriction, high reaction temperature, violent side reactions and difficult to guarantee safety in the existing hydrogen production methods.

[0006] The technical solution adopted by the present application to solve the above technical problems is:

[0007] The present application provides a process for electrolyzing seawater to produce hydrogen based on pulse and negative resin, which comprises the following steps:

[0008] Step one, slowly inject seawater into the ion exchange column, fill the ion exchange column with anion resin, and carry out dechlorination treatment to obtain micro-chlorine seawater;

[0009] Step two, the micro-chlorine seawater obtained in step one is injected into the electrolytic device, the liquid level of the micro-chlorine seawater exceeds the first electrode and the second electrode, the pulse voltage is provided by the power supply device, and the micro-chlorine seawater is electrolyzed under the pulse voltage to obtain hydrogen and electrolyte, the hydrogen passes through the gas permeable hole of the electrolytic device and is stored through the hydrogen storage device, and the above steps are repeated until the anion resin loses activity, that is, the anion resin is saturated;

[0010] Step three, when the anion resin in the ion exchange column is saturated, the electrolyte containing sodium sulfate is extracted to obtain a sodium sulfate solution with a molar concentration of 0.07 mol / L-2.5 mol / L, and then the sodium sulfate solution is injected into the ion exchange column to regenerate the saturated anion resin in the ion exchange column.

[0011] Further, the electrolytic device comprises an electrolytic box, the electrolytic box is provided with a detachable first electrode and a second electrode, the first electrode and the second electrode are vertically arranged opposite to each other, the top of the electrolytic box is detachably connected with the hydrogen storage device, the top of the electrolytic box is detachably connected with the ion exchange column, and the bottom of the electrolytic box is provided with a discharge pipe.

[0012] Further, the hydrogen storage device, the ion exchange column and the discharge pipe are all provided with valves.

[0013] Further, the distance between the first electrode and the second electrode opposite to each other is 10 mm-40 mm.

[0014] Further, in the pulse electrolysis process, the duty cycle is set to 30%-95%, the frequency is 1 Hz-30 Hz, and the peak voltage is 1.8 volts-10 volts.

[0015] Further, the duty cycle is 50%, the frequency is 10 Hz, and the peak voltage is 5 volts.

[0016] Further, the anion resin is weakly basic anion.

[0017] Further, the volume of the anion resin is 1 / 2-3 / 4 of the volume of the ion exchange column.

[0018] Further, the first electrode is connected with the positive pole of the pulse power supply, and the second electrode is connected with the negative pole of the pulse power supply.

[0019] Further, in step three, the method for obtaining the sodium sulfate solution is that the electrolyte is sequentially added into NaOH solution and Na2CO3 solution for impurity removal, then the filtered solution is evaporated, the heating is stopped when a large amount of solid is precipitated, the remaining small amount of filtrate is removed by filtration, the sodium sulfate crystal is obtained, and water is injected into the sodium sulfate crystal to obtain a sodium sulfate solution with a molar concentration of 0.07 mol / L-2.5 mol / L.

[0020] The beneficial effects of the present application compared to the prior art are:

[0021] The electrolytic seawater hydrogen production process based on pulse and anion resin of the present application injects seawater into an ion exchange column containing anion resin to obtain micro-chlorine seawater by dechlorination, injects the micro-chlorine seawater into an electrolytic device for pulse electrolysis to obtain hydrogen and electrolyte rich in sulfate, and injects the electrolyte into the ion exchange column after treatment to regenerate the saturated anion resin in situ;

[0022] Through tests, it is proved that when the flow rate of the filtered resin is 15 ml / min, the concentration of chloride ions in the filtered seawater has been reduced by 0.0053 mol / L, the removal rate of chloride ions has been increased from 89.90% of the original commercially available anion exchange resin transformed by sulfate to 98.36%, the adsorption capacity has been increased from 0.0043 mol / g of the original transformed resin to 0.0060 mol / g, and the regeneration rate of the resin is 89.34%. The resin can be regenerated for multiple cycles by flushing with sodium sulfate solution or concentrated dechlorinated seawater, and still maintains a high adsorption capacity. After modification with sodium sulfate solution, the performance of the resin in adsorbing chloride ions is increased by about 5 times, reaching 0.22 g / g of resin, and 0.15 mol / L of sodium sulfate can regenerate the anion resin by more than 95%, and the dechlorination rate of natural seawater after regeneration is more than 95%.

[0023] The electrolytic seawater hydrogen production process based on pulse and anion resin has the advantages of flexible adjustment of pulse parameters, wide applicability, strong repeatability, increased control space of the electrocatalytic system, reduced production cost and energy consumption, synergistic effect of mass transfer process, intermediate adsorption and dynamic reconstruction of the catalyst, reduced influence of anode oxidation of chloride ions on the electrode by resin pretreatment, effective solution to the problem of secondary pollution caused by chlorine gas generated during electrolysis, reduced scaling rate on the electrode surface compared to the traditional direct current electrolysis method, and the electrolyte generated after electrolysis can be used for regeneration of the saturated anion exchange resin, embodying the recycling of resources. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The flowchart of the electrolytic seawater hydrogen production process based on pulse and anion resin in an embodiment of the present application;

[0025] Figure 2 The structure diagram of the electrolytic device in an embodiment of the present application.

[0026] BRIEF DESCRIPTION OF DRAWINGS

[0027] 1, seawater; 2, anion resin; 3, electrolytic device; 5, concentrated seawater; 6, saturated resin; 7, hydrogen storage device; 8, first electrode; 9, second electrode; 11, ion exchange column. DETAILED DESCRIPTION

[0028] In the description of the present application, it should be noted that the terms such as "upper", "lower", "front", "back", "left", "right" and the like in the embodiments indicate the positional relationship based on the position relationship of the drawings for the purpose of simplifying the description, and do not mean that the elements and devices referred to must be operated according to the specific position and the defined operation and method, structure, and the like.

[0029] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings.

[0030] Specific implementation scheme one: combined with Figure 1 and Figure 2 As shown in the figure, the present application provides a process method for electrolyzing seawater to produce hydrogen based on pulse and anion resin, comprising the following steps:

[0031] Step one, slowly inject seawater 1 into ion exchange column 11, which is filled with anion resin 2, for dechlorination treatment, and obtain micro-chlorine seawater or dechlorinated seawater after treatment; the ion exchange column 11 can be an acid titration tube;

[0032] Step two, inject the micro-chlorine seawater or dechlorinated seawater obtained in step one into the electrolysis device 3, the liquid level of the micro-chlorine seawater or dechlorinated seawater exceeds the first electrode 8 and the second electrode 9, and a pulse voltage is provided by the power supply device, and the micro-chlorine seawater or dechlorinated seawater is electrolyzed under the pulse voltage to obtain hydrogen gas and electrolyte, and after standing for 5-10 minutes, the hydrogen gas passes through the gas permeation hole of the electrolysis device 3 and is stored in the hydrogen storage device 7, and the above steps are repeated until the anion resin 2 loses activity, i.e. the anion resin 2 is saturated;

[0033] Step three, when the anion resin 2 in the ion exchange column 11 is saturated, the electrolyte containing sodium sulfate is extracted to obtain a sodium sulfate solution with a molar concentration of 0.07-2.5 mol / L, and then the sodium sulfate solution is injected into the ion exchange column 11 for regeneration of the saturated resin 6 in the ion exchange column 11.

[0034] The process method for electrolyzing seawater to produce hydrogen based on pulse and anion resin of the present application injects seawater 1 into the ion exchange column 11 containing anion resin 2 for dechlorination to obtain micro-chlorine seawater or dechlorinated seawater, injects the micro-chlorine seawater or dechlorinated seawater into the electrolysis device 3 for pulse electrolysis to obtain hydrogen gas and electrolyte rich in sulfate, and then injects the electrolyte into the ion exchange column 11 for in-situ regeneration of the saturated anion resin 2 after treatment;

[0035] The test proves that when the filtration resin flow rate is 15 ml / min, the concentration of chloride ions in filtered seawater is reduced by 0.0053 mol / L, the removal rate of chloride ions is increased from 89.90% of the original commercially available anion exchange resin transformed by sulfate to 98.36%, the adsorption capacity is increased from 0.0043 mol / g of the original transformed resin to 0.0060 mol / g, and the regeneration rate of the resin is 89.34%. At the same time, the resin can be regenerated for multiple cycles by flushing with sodium sulfate solution or concentrated micro-chlorine seawater or de-chlorinated seawater, and still maintains a high adsorption capacity. After modification with sodium sulfate solution, the performance of the resin in adsorbing chloride ions is increased by about 5 times, reaching 0.22 g / g (resin) 0.15 mol / L sodium sulfate. The regenerated anion resin can be regenerated by more than 95% after regeneration, and can remove more than 95% of the chlorine in natural seawater.

[0036] The advantages of the hydrogen production process based on pulse and anion resin electrolysis of seawater over the prior art are that the pulse parameters can be flexibly adjusted, which is widely applicable and has strong repeatability, increases the regulation space of the electrocatalytic system, reduces production cost and energy consumption, can realize the synergistic effect of mass transfer process, intermediate adsorption and catalyst dynamic reconstruction, and the resin pretreatment reduces the influence of anode oxidation of chloride ions on the electrode. It can effectively solve the problem of secondary pollution caused by chlorine gas generated during electrolysis. Compared with the traditional direct current electrolysis method, the scaling rate on the electrode surface is reduced. The electrolyte produced after electrolysis can also be used for regeneration of the saturated anion exchange resin, which embodies the recycling of resources.

[0037] Preferably, the electrolysis device 3 comprises an electrolysis box, a detachable first electrode 8 and a second electrode 9 are arranged in the electrolysis box, the first electrode 8 and the second electrode 9 are arranged vertically opposite to each other, the top of the electrolysis box is detachably connected with a hydrogen storage device 7, the top of the electrolysis box is detachably connected with an ion exchange column 11, and the bottom of the electrolysis box is provided with a discharge pipe. The hydrogen storage device 7, the ion exchange column 11 and the discharge pipe are all provided with valves for controlling the closing state of the discharge pipe and the hydrogen storage device 7 when micro-chlorine seawater or de-chlorinated seawater is injected; the closing state of the ion exchange column 11 and the discharge pipe when electrolysis is performed; and the closing state of the hydrogen storage device 7 and the ion exchange column 11 when the electrolyte is discharged.

[0038] Preferably, the distance between the first electrode 8 and the second electrode 9 opposite to each other is 10 mm-40 mm.

[0039] Preferably, in the pulse electrolysis process, the conditions are set as a duty cycle of 30%-95%, a frequency of 1 Hz-30 Hz, and a peak voltage of 1.8 volts-10 volts, which can be adjusted according to the actual mass transfer resistance and the potential of the electric pair.

[0040] Preferably, the duty cycle is 50%, the frequency is 10 Hz, the electrolysis duration is determined by the adsorption capacity of the resin used and the temperature condition at the time, and the peak voltage is 5 volts.

[0041] Preferably, the anion resin 2 is weakly basic anion.

[0042] Preferably, the volume of the anion resin 2 is 1 / 2-3 / 4 of the volume of the ion exchange column 11.

[0043] Preferably, the first electrode 8 is connected to the positive pole of the pulse power supply, and the second electrode 9 is connected to the negative pole of the pulse power supply.

[0044] Preferably, the second electrode 9 can be a platinum electrode.

[0045] Preferably, the model of the pulse power supply device can be Chroma programmable DC Power Supply 62010L-36-7.

[0046] Preferably, in step three, the method for obtaining the sodium sulfate solution is as follows: the electrolyte is sequentially added into NaOH solution and Na2CO3 solution for impurity removal, and after the impurity removal, filtration is performed, the filtrate is evaporated, the heating is stopped when a large amount of solid is precipitated, the remaining small amount of filtrate is removed by filtration, the sodium sulfate crystals are obtained, and water is injected into the sodium sulfate crystals to obtain a sodium sulfate solution with a molar concentration of 0.07 mol / L-2.5 mol / L.

[0047] Embodiment:

[0048] Under the pulse voltage, the peak voltage is selected as 5 volts, the duty cycle is 50%, the frequency is 20 Hz, and the electrolysis is performed for 10 minutes, the electrolysis tank is powered, and the electrolysis process is performed.

[0049] Comparative example:

[0050] Under the direct current voltage, the voltage value is set as 5 volts, the electric quantity is 30 mA / 2.25, the electrolysis is performed for 10 minutes, the electrolysis tank is powered, and the electrolysis process is performed.

[0051] Comparing the embodiment and the comparative example, the electrode surface fouling condition of the embodiment is obviously better than that of the comparative example, which indicates that the pulse electrolysis method can be used to electrolyze seawater to produce hydrogen at a low fouling rate under the same electrolysis time condition.

[0052] Although the present application is disclosed as above, the protection scope of the present application is not limited to this. The person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and these changes and modifications will fall within the protection scope of the present application.

Claims

1. A method for producing hydrogen from seawater by electrolysis based on pulse and anion exchange resin, characterized in that, Includes the following steps: Step 1: Slowly inject seawater (1) into the ion exchange column (11), which is filled with anion exchange resin (2) for dechlorination treatment, and obtain microchlorinated seawater after treatment. Step 2: Inject the microchlorinated seawater obtained in Step 1 into the electrolysis device (3). The liquid level of the microchlorinated seawater exceeds the first electrode (8) and the second electrode (9). A pulse voltage is provided by the power supply device. Under the pulse voltage, the microchlorinated seawater is electrolyzed to obtain hydrogen and electrolyte. The hydrogen passes through the vent of the electrolysis device (3) and is stored through the hydrogen storage device (7). Repeat the above steps until the anion exchange resin (2) loses its activity, that is, the anion exchange resin (2) is saturated. Step 3: When the anion exchange resin (2) in the ion exchange column (11) is saturated, an electrolyte containing sodium sulfate is extracted to obtain a sodium sulfate solution with a molar concentration of 0.07 mol / L-2.5 mol / L. The sodium sulfate solution is then injected into the ion exchange column (11) to regenerate the saturated anion exchange resin (2) in the ion exchange column (11).

2. The method for producing hydrogen from seawater based on pulse and anion exchange resin according to claim 1, characterized in that: The electrolysis device (3) includes an electrolysis box, which is equipped with a detachable first electrode (8) and a second electrode (9). The first electrode (8) and the second electrode (9) are arranged vertically opposite to each other. The top of the electrolysis box is detachably connected to a hydrogen storage device (7), and the top of the electrolysis box is detachably connected to an ion exchange column (11). The bottom of the electrolysis box is equipped with a discharge pipe.

3. The method for producing hydrogen from seawater based on pulse and anion exchange resin according to claim 2, characterized in that: The hydrogen storage device (7), ion exchange column (11) and discharge pipe are all equipped with valves.

4. The method for producing hydrogen from seawater based on pulse and anion exchange resin according to claim 2, characterized in that: The distance between the first electrode (8) and the second electrode (9) is 10mm-40mm.

5. The method for producing hydrogen from seawater based on pulse and anion exchange resin according to claim 4, characterized in that: In the pulse electrolysis process of step two, the conditions are set as follows: duty cycle of 30%-95%, frequency of 1Hz-30Hz, and peak voltage of 1.8V-10V.

6. The method for producing hydrogen from seawater based on pulse and anion exchange resin according to claim 5, characterized in that: The duty cycle is 50%, the frequency is 10Hz, and the peak voltage is 5 volts.

7. The method for producing hydrogen from seawater based on pulse and anion exchange resin according to claim 5, characterized in that: The anion exchange resin (2) is a weakly basic anion.

8. The method for producing hydrogen from seawater based on pulse and anion exchange resin according to claim 7, characterized in that: The volume of the anion exchange resin (2) is 1 / 2 to 3 / 4 of the volume of the ion exchange column (11).

9. The method for producing hydrogen from seawater based on pulse and anion exchange resin according to claim 8, characterized in that: The first electrode (8) is connected to the positive terminal of the pulse power supply, and the second electrode (9) is connected to the negative terminal of the pulse power supply.

10. The method for producing hydrogen from seawater based on pulse and anion exchange resin according to claim 9, characterized in that: In step three, the method for obtaining sodium sulfate solution is as follows: the electrolyte is added sequentially to NaOH solution and Na2CO3 solution to remove impurities. After impurity removal, the solution is filtered, and the filtrate is evaporated. Heating is stopped when a large amount of solid precipitates. The remaining small amount of filtrate is removed by filtration to obtain sodium sulfate crystals. Water is then injected into the sodium sulfate crystals to form a sodium sulfate solution with a molar concentration of 0.07 mol / L to 2.5 mol / L.

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