Purification process for electrolytic hydrogen production adapted to wide power fluctuations

Abstract

The invention provides a purification method suitable for wide power fluctuation and used for electrolytic hydrogen production, which comprises the following steps of: (1) treating a gas-liquid mixture from an electrolytic bath, and outputting hydrogen flow containing saturated water vapor; (2) respectively and alternately feeding the hydrogen flow to three adsorption towers to obtain purified hydrogen; the function relationship between the real-time total current Ii total and the real-time hydrogen production flow Vi of the electrolytic bath is Vi = k1 * (Ii total / 2380), 0 lt; k1 < = 1; the working adsorption capacity of the adsorption tower in the adsorption working state is Vs, and Vs = Vmark * t mark; when 0 lt; vi < = Vmark, sigma Vi = Vs, or Vmark lt; vi is less than or equal to 1.5 V < standard >, and sigma Vi is equal to k2Vs, 0lt; and when k2 is less than or equal to Vstandard / Vi, judging that the adsorption capacity of the adsorption tower in the adsorption working state reaches the working adsorption capacity, switching the hydrogen flow to the adsorption tower in the desorption regeneration ending state for adsorption work, switching the adsorption tower in the adsorption recovery state to the adsorption regeneration state, and switching the adsorption tower in the adsorption working ending state to the adsorption recovery state. According to the method, a variable period technology is adopted, and 0-150% wide power fluctuation can be achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrolytic hydrogen purification, and particularly relates to a purification method for electrolytic hydrogen production adapted to wide power fluctuations. Background Art

[0002] Electrolytic hydrogen production using renewable energy such as wind and solar has become the market's first choice. An electrolytic hydrogen production system generally consists of four parts: a power supply system, an electrolytic cell system, a gas-liquid separation system, and a hydrogen purification system. A direct current is passed through an electrolytic cell filled with an electrolyte solution, and water molecules undergo an electrochemical reaction on the electrodes to decompose into hydrogen and oxygen, which, together with the circulating electrolyte solution, enter the hydrogen and oxygen separation scrubbers respectively for gas-liquid separation, washing, and cooling. Subsequently, the hydrogen is passed into the deoxidation tower and drying tower of the purification unit for deoxidation and drying. Currently, the purification of electrolytic hydrogen mainly uses a three-tower purification method, and the purge gas is 20-30% of the product hydrogen. Therefore, when the load is below 20-30%, the purification device cannot operate, resulting in the waste of low-load hydrogen. With the increase in off-grid electrolytic hydrogen production, the electrolytic hydrogen production technology adapted to wide power fluctuations under a fluctuating power supply has become an urgently needed technology in the market, and correspondingly, there is an urgent need to develop a hydrogen purification technology adapted to wide-range fluctuations.

[0003] CN 218478535 U introduces a hydrogen purification tower and a water electrolysis hydrogen production system, discloses the structure of the hydrogen purification tower, can meet the safety requirements for the large-scale hydrogen purification equipment, and saves the installation and maintenance costs. By optimizing the arrangement and structure of the heating sleeve, heat medium input pipe, and heat medium output pipe in the hydrogen purification tower, the heat exchange efficiency is improved, but it does not involve the adaptation to fluctuations.

[0004] CN 216947216 U discloses a large-scale electrolytic water hydrogen production system, which adopts a unit assembly structure and mainly includes a factory building, a transformer, an electrolytic water unit, a gas-liquid separation unit, a hydrogen purification unit, a water and alkali replenishment unit, and a complete set of low-voltage power distribution facilities; the electrolytic water unit consists of a rectifier cabinet and an electrolytic cell, and the electrolysis of water is completed in the electrolytic cell; there are multiple sets of electrolytic water units, and every two sets of electrolytic water units share one transformer, every four sets of electrolytic water units share one set of gas-liquid separation units, and every two sets of gas-liquid separation units share one set of hydrogen purification units. The water and alkali replenishment unit consists of a demineralized water buffer tank, a demineralized water injection pump, an alkali tank, and a dosing pump. This system can arrange multiple sets of electrolytic water units in one factory building, with a compact equipment layout, reasonable space utilization, reduced floor area, and some equipment between units can be shared, reducing the number of equipment and saving investment. It gives a matching method of four electrolytic cells for one set of gas-liquid separation and two sets of gas-liquid separation for one set of hydrogen purification for large-scale electrolytic hydrogen production, but it also does not involve the adaptation to fluctuations.

[0005] Therefore, there is currently no purification method for electrolytic hydrogen production that can adapt to wide power fluctuations. Summary of the Invention

[0006] The object of the present invention is to provide a purification method for electrolytic hydrogen production that can adapt to wide power fluctuations. This method is simple and easy to operate. By adopting a variable-cycle process, it can achieve a wide power fluctuation range of 0-150%, broadening the purification fluctuation adaptation range.

[0007] To achieve the first object of the present invention, the following technical solutions are adopted:

[0008] A purification method for electrolytic hydrogen production that can adapt to wide power fluctuations, the purification method comprising:

[0009] (1) The gas-liquid mixture coming out of the electrolytic cell of the electrolytic hydrogen production device is cooled, gas-liquid separated, then enters the deoxygenation tower for deoxygenation and is output, and then undergoes condensation and gas-liquid separation to output a hydrogen stream containing saturated water vapor;

[0010] (2) The hydrogen stream output in step (1) is alternately sent to three adsorption towers respectively according to the following method to adsorb and remove the saturated water vapor therein to obtain purified hydrogen as the product gas; wherein,

[0011] The three adsorption towers are alternately in an adsorption working state, a desorption regeneration state, and an adsorption recovery state; the adsorption working state is to use the adsorption tower to adsorb and dehydrate the hydrogen stream output in step (1) to obtain purified hydrogen as the product gas; the desorption regeneration state is to use part of the purified hydrogen output in the adsorption working state as the regeneration gas to desorb and regenerate the adsorption tower that has ended the adsorption working state, desorb the moisture, and output a regeneration gas stream containing saturated water; the adsorption recovery state is to use the adsorption tower to adsorb and dehydrate the regeneration gas stream containing saturated water output in the desorption regeneration state to obtain purified hydrogen and enter the product gas pipeline;

[0012] After the adsorption tower in the adsorption working state ends the adsorption working state, the hydrogen stream output in step (1) is switched to the adsorption tower that has ended the desorption regeneration state and is waiting to be used for adsorption work to switch it to the adsorption working state. At the same time, the adsorption tower in the adsorption recovery state is switched to the adsorption regeneration state, and the adsorption tower that has ended the adsorption working state is switched to the adsorption recovery state;

[0013] And the real-time total current I of the electrolytic cell i总 and the real-time hydrogen production flow rate V i The functional relationship is V i = k1 * (I i总 / 2380), 0 < k1 ≤ 1; k1 is a coefficient specific to the stack; the working adsorption capacity of the adsorption tower in the adsorption working state is Vs, Vs = V 标 * t 标 , V标 is the rated hydrogen production flow rate of the adsorption tower in the adsorption working state, t 标 is for the adsorption tower in the adsorption working state at V 标 under the rated adsorption time;

[0014] During adsorption,

[0015] When 0 < V i ≤ V 标 , it is determined that when ΣV i = Vs, the adsorption tower in the adsorption working state reaches the working adsorption capacity, then ends its adsorption working state, switches the hydrogen gas flow output in step (1) to the adsorption tower that has ended the desorption regeneration state and is waiting for use for adsorption work, at the same time switches the adsorption tower in the adsorption recovery state to the adsorption regeneration state, and switches the adsorption tower that has ended the adsorption working state to the adsorption recovery state;

[0016] When V 标 < V i ≤ 1.5V 标 , it is determined that when ΣV i = k2Vs, k2 is the breakthrough coefficient, 0 < k2 ≤ V 标 / V i , the adsorption tower in the adsorption working state reaches the working adsorption capacity, then ends its adsorption working state, switches the hydrogen gas flow output in step (1) to the adsorption tower that has ended the desorption regeneration state and is waiting for use for adsorption work, at the same time switches the adsorption tower in the adsorption recovery state to the adsorption regeneration state, and switches the adsorption tower that has ended the adsorption working state to the adsorption recovery state.

[0017] The purification method for electrolytic hydrogen production of the present invention adapted to wide power fluctuations. Preferably, during regeneration, when V i ≥ a%V 标 , and 10 ≤ a ≤ 60, the adsorption tower in the desorption regeneration state performs desorption regeneration according to the normal process, and distributes a%V 标 of the purified hydrogen gas output from the adsorption tower in the adsorption working state as the regeneration gas for desorption regeneration, and the remaining part enters the product gas pipeline as the product gas.

[0018] The purification method for electrolytic hydrogen production of the present invention adapted to wide power fluctuations. Preferably, during regeneration, when V i < a%V 标 , and 10 ≤ a ≤ 60, after making up the regeneration gas volume to reach a%V 标 through external circulation, then perform desorption regeneration; wherein, the buffer tank is connected to the product gas pipeline.

[0019] Purification method for electrolytic hydrogen production adapted to wide power fluctuations. Preferably, the external circulation includes a buffer tank and a circulation pump. Among them, the buffer tank is connected to three adsorption towers respectively, and circulation pumps are arranged on the connecting pipelines respectively, for caching hydrogen gas, so that when regenerating, in case of V i <a%V 标 occurs, the buffer tank and the circulation pump are started, and the hydrogen gas in the buffer tank is sent into the adsorption tower to be in the desorption regeneration state as the regeneration gas.

[0020] The purification method for electrolytic hydrogen production adapted to wide power fluctuations of the present invention. Preferably, the hydrogen gas in the buffer tank includes the hydrogen gas product output from the adsorption tower in the adsorption working state.

[0021] The purification method for electrolytic hydrogen production adapted to wide power fluctuations of the present invention. Preferably, the hydrogen gas in the buffer tank includes commercially available hydrogen gas products.

[0022] The purification method for electrolytic hydrogen production adapted to wide power fluctuations of the present invention. Preferably, 20 ≤ a ≤ 30.

[0023] The purification method for electrolytic hydrogen production adapted to wide power fluctuations of the present invention. Preferably, 0.6 ≤ k1 ≤ 1.

[0024] The purification method for electrolytic hydrogen production adapted to wide power fluctuations of the present invention. Preferably, 0.5 ≤ k2 ≤ 1.

[0025] The beneficial effects of the present invention are as follows:

[0026] The purification method for electrolytic hydrogen production adapted to wide power fluctuations of the present invention is simple and easy to operate. This solution realizes a wide power fluctuation of 0 - 150% through the variable cycle process, broadens the purification fluctuation adaptation range, and at the same time reduces the regeneration energy consumption, and can better adapt to the renewable energy hydrogen production system;

[0027] The purification method for electrolytic hydrogen production adapted to wide power fluctuations of the present invention calculates the hydrogen production amount according to the front-end current, and regenerates after the cumulative hydrogen production amount reaches the working adsorption capacity (i.e., the saturated adsorption amount) of the adsorption tower, avoiding frequent regeneration under low load; the regeneration gas volume realizes the complete regeneration of the adsorption tower through the cooperation of the internal circulation and external circulation regeneration methods according to the hydrogen production flow rate. Detailed Embodiments

[0028] The technical solutions and their effects of the present invention are further described below in conjunction with specific embodiments / examples. The following embodiments / examples are only used to illustrate the content of the present invention, and the invention is not limited to the following embodiments or examples. Simple changes made to the present invention using the concept of the present invention are within the scope of protection of the present invention.

[0029] The present invention provides a purification method for electrolytic hydrogen production that is adaptable to wide power fluctuations, the purification method comprising:

[0030] (1) The gas-liquid mixture coming out of the electrolytic cell of the electrolytic hydrogen production device is cooled and separated into gas and liquid, and then enters the deoxidation tower for deoxidation and output, and then condenses and separates the gas and liquid to output a hydrogen flow containing saturated water vapor;

[0031] (2) The hydrogen gas stream output from step (1) is alternately sent to three adsorption towers to adsorb and remove saturated water vapor therein, thereby obtaining purified hydrogen as product gas; wherein:

[0032] The three adsorption towers are alternately in an adsorption working state, a desorption regeneration state and an adsorption recovery state; the adsorption working state is to use the adsorption tower to adsorb and dehydrate the hydrogen gas flow output from step (1) to obtain purified hydrogen as the product gas; the desorption regeneration state is to use part of the purified hydrogen output from the adsorption working state as the regeneration gas to desorb and regenerate the adsorption tower that has ended the adsorption working state, desorb the water, and output a regeneration gas flow containing saturated water; the adsorption recovery state is to use the adsorption tower to adsorb and dehydrate the regeneration gas flow containing saturated water output from the desorption regeneration state to obtain purified hydrogen to enter the product gas pipeline;

[0033] After the adsorption tower in the adsorption working state ends the adsorption working state, the hydrogen flow output from step (1) is switched to the adsorption tower in the end of the desorption regeneration state and the standby adsorption tower is subjected to adsorption work to switch it to the adsorption working state, and at the same time, the adsorption tower in the adsorption recovery state is switched to the adsorption regeneration state, and the adsorption tower that ends the adsorption working state is switched to the adsorption recovery state;

[0034] The real-time total current of the electrolytic cell I i总 and real-time hydrogen production flow V i The functional relationship is V i =k1*(I i总 / 2380), 0 <k1≤1,比如0.1、0.2、0.3、0.4、0.5、0.6、0.7、0.8和0.9;k1为电堆特有系数;处于吸附工作状态的吸附塔的工作吸附容量为Vs,Vs=V 标 *t 标 =V i *t 实 , V 标 is the rated hydrogen production flow rate, t 标 V 标 Rated adsorption time under 实 The adsorption tower is in the adsorption working state at V i The actual adsorption time under

[0035] When adsorbed,

[0036] When 0 <V i ≤V 标 When ΣV i = Vs, the adsorption tower in the adsorption working state reaches the working adsorption capacity, and then ends its adsorption working state, switches the hydrogen flow output from step (1) to the adsorption tower on standby after the desorption regeneration state is finished, and at the same time switches the adsorption tower in the adsorption recovery state to the adsorption regeneration state, and switches the adsorption tower that has finished the adsorption working state to the adsorption recovery state;

[0037] When V 标 <V i ≤1.5V 标 When ΣV i =k2Vs, k2 is the penetration coefficient, and 0 <k2≤V 标 / V i When the adsorption tower in the adsorption working state reaches the working adsorption capacity, the adsorption working state is terminated, and the hydrogen flow output from step (1) is switched to the adsorption tower on standby after the desorption regeneration state is terminated to perform adsorption work. At the same time, the adsorption tower in the adsorption recovery state is switched to the adsorption regeneration state, and the adsorption tower that has terminated the adsorption working state is switched to the adsorption recovery state.

[0038] Those skilled in the art understand that V 标 is the rated hydrogen production flow rate of the adsorption tower device when it is designed, t 标 When designing an adsorption tower device, V 标 Rated adsorption time under .

[0039] Those skilled in the art understand that the gas-liquid mixture coming out of the electrolyzer of the electrolytic hydrogen production device includes hydrogen produced by electrolysis, water or alkaline solution.

[0040] Those skilled in the art will understand that k1 is a coefficient specific to the battery stack, and different battery stacks correspond to different k1 values; k2 is a penetration coefficient, which is determined by the structure of the adsorption tower and the adsorbent. The adsorbent is generally a molecular sieve, such as 3X, 3A, 5A, etc.

[0041] Those skilled in the art understand that, assuming that the three adsorption towers are adsorption tower A, adsorption tower B, and adsorption tower C, adsorption tower A, adsorption tower B, and adsorption tower C are alternately in adsorption working state, desorption regeneration state, and adsorption recovery state; and in one switching cycle, adsorption tower A, adsorption tower B, and adsorption tower C experience three groups of states, namely

[0042] State 1 (abbreviated as Z1): adsorption tower A is in the adsorption working state, adsorption tower B is in the desorption regeneration state, and adsorption tower C is in the adsorption recovery state;

[0043] State 2 (abbreviated as Z2): adsorption tower B is in the adsorption working state, adsorption tower C is in the desorption regeneration state, and adsorption tower A is in the adsorption recovery state;

[0044] State 3 (abbreviated as Z3): adsorption tower C is in adsorption working state, adsorption tower A is in desorption regeneration state, and adsorption tower B is in adsorption recovery state;

[0045] And in the case of state 1:

[0046] The adsorption working state is to use the adsorption tower A to adsorb and dehydrate the hydrogen gas flow output from step (1) to obtain purified hydrogen as the product gas; the desorption regeneration state is to use part of the purified hydrogen output from the adsorption working state as the regeneration gas to desorb and regenerate the adsorption tower B that has ended the adsorption recovery state, desorb the water, and output a regeneration gas flow containing saturated water; the adsorption recovery state is to use the adsorption tower C to adsorb and dehydrate the regeneration gas flow containing saturated water output from the desorption regeneration state to obtain purified hydrogen to enter the product gas pipeline;

[0047] After the adsorption tower A in the adsorption working state ends the adsorption working state, the hydrogen flow output from step (1) is switched to the adsorption tower B in the end of the desorption regeneration state and the standby adsorption tower B is switched to the adsorption working state, and the adsorption tower C in the adsorption recovery state is switched to the adsorption regeneration state, and the adsorption tower A in the end of the adsorption working state is switched to the adsorption recovery state;

[0048] The real-time total current of the electrolytic cell I i总 and real-time hydrogen production flow V i The functional relationship is V i =k1*(I i总 / 2380), 0 <k1≤1,比如0.1、0.2、0.3、0.4、0.5、0.6、0.7、0.8和0.9;k1为电堆特有系数;处于吸附工作状态的吸附塔A的工作吸附容量为Vs,Vs=V 标 *t 标 =V i *t 实 , V 标 is the rated hydrogen production flow rate of adsorption tower A in adsorption working state, t 标 The adsorption tower A is in the adsorption working state at V 标 Rated adsorption time under 实 The adsorption tower A is in the adsorption working state at V i The actual adsorption time under

[0049] When adsorbed,

[0050] When 0 <V i ≤V 标When ΣV i = Vs, the adsorption tower A in the adsorption working state adsorbs to the working adsorption capacity, and then terminates its adsorption working state, switches the hydrogen flow output from step (1) to the adsorption tower B that has terminated the desorption regeneration state and is on standby to perform adsorption work, and at the same time switches the adsorption tower C in the adsorption recovery state to the adsorption regeneration state, and switches the adsorption tower A that has terminated the adsorption working state to the adsorption recovery state, i.e., switches to state 2;

[0051] When V 标 <V i ≤1.5V 标 When ΣV i =k2Vs, k2 is the penetration coefficient, 0 <k2≤V 标 / V i When the adsorption tower A in the adsorption working state reaches the working adsorption capacity, the adsorption working state is terminated, and the hydrogen flow output from step (1) is switched to the adsorption tower B in the desorption regeneration state and standby for adsorption, and at the same time, the adsorption tower C in the adsorption recovery state is switched to the adsorption regeneration state, and the adsorption tower A in the adsorption working state is switched to the adsorption recovery state, that is, switched to state 2;

[0052] In the case of state 2, switch to state 3 according to the same method as in state 1; in the case of state 3, switch to state 1 according to the same method as in state 1; thereby realizing the alternating switching of the three towers, namely adsorption tower A, adsorption tower B and adsorption tower C, among states 1, 2 and 3.

[0053] Those skilled in the art understand that the current three-column non-destructive hydrogen purification process is as follows: (1) The gas-liquid mixture coming out of the electrolyzer of the electrolytic hydrogen production device is cooled, separated by gas-liquid separation, then enters the deoxidation column for deoxidation and is output. After condensation and gas-liquid separation, a hydrogen stream containing saturated water vapor is output. Specifically: The raw hydrogen coming out of the electrolyzer is cooled and the free water is filtered out by a gas-water separator, and then enters a deoxidizer for efficient catalytic deoxidation at room temperature. Under the action of a catalyst, oxygen reacts with hydrogen to form water, and the generated water is carried out of the deoxidizer with hydrogen, enters a cooler for condensation and then enters a gas-liquid separator for dehydration again. The free water is removed in the gas-liquid separator and discharged from the system through a drain valve, and a hydrogen stream containing saturated water vapor is output from the cooler; (2) The hydrogen stream containing saturated water vapor enters an adsorption column (also called a drying column) filled with molecular sieve for dehydration and drying. The water vapor is adsorbed by the molecular sieve in the adsorption column, and the purified hydrogen flows out of the adsorption column. There are 3 adsorption columns, and the 3 adsorption columns perform adsorption and desorption in a fixed cycle, and alternately operate in an adsorption working state, a desorption regeneration state, and an adsorption recovery state to achieve adsorption work, desorption regeneration, and adsorption recovery. Those skilled in the art understand that as the gas velocity of the feed gas in step (2) (i.e., the hydrogen stream output in step (1)) continuously increases, the breakthrough time of the bed layer rapidly decreases. When using this traditional adsorption and desorption process with a fixed cycle for adsorption and desorption, it will cause the bed layer of the adsorption column in the adsorption working state at a low gas velocity to enter the desorption regeneration state for regeneration before reaching the working adsorption capacity (not saturated with adsorption), wasting a large amount of energy, and can only meet the load in the range of 30-100%, unable to adapt to the electrolytic hydrogen production purification with wide power fluctuations, so that a large-scale renewable energy electrolytic hydrogen production system needs to be equipped with multiple purification systems to meet the needs of different loads.

[0054] The purification method for electrolytic hydrogen production that adapts to wide power fluctuations of the present invention is simple and easy to operate, and realizes a wide power fluctuation of 0-150% through the adoption of a variable cycle process, broadens the purification fluctuation adaptation range, and at the same time reduces the regeneration energy consumption, and can better adapt to the renewable energy hydrogen production system; and calculates the hydrogen production amount according to the front-end current, and performs regeneration after the cumulative hydrogen production amount reaches the working adsorption capacity (i.e., the saturated adsorption amount) of the adsorption column, avoiding frequent regeneration under low load; the regeneration gas volume adopts an internal circulation and an external circulation regeneration method in cooperation according to the hydrogen production amount to achieve the complete regeneration of the adsorption column.

[0055] In one embodiment, during regeneration, when V i ≥a%V 标 , and 10 ≤ a ≤ 60, the adsorption column in the desorption regeneration state performs desorption regeneration according to the normal process, and distributes a%V 标 of the purified hydrogen output from the adsorption column in the adsorption working state as the regeneration gas for desorption regeneration, and the remaining part enters the product gas pipeline as the product gas.

[0056] That is, assuming the foregoing state 1 (adsorption tower A is in the adsorption working state, adsorption tower B is in the desorption regeneration state, and adsorption tower C is in the adsorption recovery state): during regeneration, when V i ≥a%V 标 , and when 10 < a < 60, the adsorption tower B in the desorption regeneration state performs desorption regeneration according to the normal process, and distributes a%V 标 of the purified hydrogen gas output from the adsorption tower A in the adsorption working state as the regeneration gas for regeneration, and the remaining part enters the product gas pipeline as the product gas.

[0057] In an embodiment, during regeneration, when V i <a%V 标 , and when 10 ≤ a ≤ 60, the regeneration gas volume is supplemented through external circulation to make it reach a%V 标 and then desorption regeneration is carried out.

[0058] That is, assuming the foregoing state 1 (adsorption tower A is in the adsorption working state, adsorption tower B is in the desorption regeneration state, and adsorption tower C is in the adsorption recovery state): during regeneration, when V i <a%V 标 , and when 10 ≤ a ≤ 60, the regeneration gas volume is supplemented through external circulation to make it reach a%V 标 and then the desorption regeneration of adsorption tower B is carried out.

[0059] Those skilled in the art understand that a buffer tank and a circulation pump can be added to the original three-tower non-destructive hydrogen purification process system. The buffer tank is respectively connected to the three adsorption towers, and a circulation pump is arranged on the connecting pipeline, so as to send the hydrogen product gas obtained from the adsorption tower in the adsorption working state into the buffer tank for storage, or hydrogen can also be directly stored in it. During regeneration, when the situation of V i <a%V 标 occurs, the buffer tank and the circulation pump are started, and the hydrogen in the buffer tank is sent into the adsorption tower to be in the desorption regeneration state as the regeneration gas.

[0060] In an embodiment, the external circulation includes a buffer tank and a circulation pump. Among them, the buffer tank is respectively connected to the three adsorption towers, and a circulation pump is respectively arranged on the connecting pipeline, which is used to buffer hydrogen gas, so that when the situation of V i <a%V 标 occurs during regeneration, the buffer tank and the circulation pump are started, and the hydrogen in the buffer tank is sent into the adsorption tower to be in the desorption regeneration state as the regeneration gas.

[0061] In an embodiment, the hydrogen gas in the buffer tank includes the hydrogen product gas output from the adsorption tower in the adsorption working state.

[0062] In an embodiment, the hydrogen gas in the buffer tank includes commercially available hydrogen product gas or hydrogen product gas from other sources.

[0063] The purification method for electrolytic hydrogen production adaptable to wide power fluctuations of the present invention. In one embodiment, 20 ≤ a ≤ 30, such as 22, 24, 26, and 28.

[0064] The purification method for electrolytic hydrogen production adaptable to wide power fluctuations of the present invention. In one embodiment, 0.6 ≤ k1 ≤ 1, such as 0.7, 0.8, and 0.9.

[0065] The purification method for electrolytic hydrogen production adaptable to wide power fluctuations of the present invention. In one embodiment, 0.5 ≤ k2 ≤ 1, such as 0.6, 0.7, 0.8, and 0.9.

[0066] The following further illustrates the present application through specific examples and comparative examples.

[0067] Example 1 (S1)

[0068] A purification method for electrolytic hydrogen production adaptable to wide power fluctuations, the purification method comprising:

[0069] (1) The gas-liquid mixture coming out of the electrolytic hydrogen production device is cooled, separated by gas-liquid separation, then enters the deoxygenation tower for deoxygenation and is output, and then is condensed and separated by gas-liquid separation to output a hydrogen stream containing saturated water vapor;

[0070] (2) The hydrogen stream output in step (1) is alternately sent to three adsorption towers respectively according to the following method to adsorb and remove the saturated water vapor therein to obtain purified hydrogen as the product gas; wherein,

[0071] The three adsorption towers A, B, and C are alternately in the adsorption working state, desorption regeneration state, and adsorption recovery state; and

[0072] In the case of state 1 (adsorption tower A is in the adsorption working state, adsorption tower B is in the desorption regeneration state, and adsorption tower C is in the adsorption recovery state):

[0073] The adsorption working state is to use adsorption tower A to adsorb and dehydrate the hydrogen stream output in step (1) to obtain purified hydrogen as the product gas; the desorption regeneration state is to use part of the purified hydrogen output in the adsorption working state as the regeneration gas to desorb and regenerate adsorption tower B that has ended the adsorption recovery state, desorb moisture, and output a regeneration gas stream containing saturated water; the adsorption recovery state is to use adsorption tower C to adsorb and dehydrate the regeneration gas stream containing saturated water output in the desorption regeneration state to obtain purified hydrogen and send it into the product gas pipeline.

[0074] After the adsorption tower A in the adsorption working state finishes the adsorption operation, switch the hydrogen flow output in step (1) to the adsorption tower B that has finished the desorption regeneration state and is waiting to be used for adsorption work to make it switch to the adsorption working state. At the same time, switch the adsorption tower C in the adsorption recovery state to the adsorption regeneration state, and switch the adsorption tower A that has finished the adsorption working state to the adsorption recovery state;

[0075] while the real-time total current I of the electrolyzer i总 and the real-time hydrogen production flow rate V i has a functional relationship of V i = k1*(I i总 / 2380), where k1 = 0.9; k1 is a coefficient unique to the stack; the working adsorption capacity of the adsorption tower A in the adsorption working state is Vs, and Vs = V 标 *t 标 = V i *t 实 , V 标 is the rated hydrogen production flow rate of the adsorption tower A in the adsorption working state, and t 标 is the rated adsorption time of the adsorption tower A in the adsorption working state at V 标 , and t 实 is the actual adsorption time of the adsorption tower A in the adsorption working state at V i ;

[0076] Taking the electrolytic hydrogen production device with V 标 = 1000 Nm 3 / h as the rated hydrogen production flow rate and t 标 = 8 h as the rated adsorption time of the adsorption tower A in the adsorption working state at V 标 as an example;

[0077] During adsorption, when the real-time total current I i总 = 2650 kA, the corresponding real-time hydrogen production flow rate V i = k1*(I i总 / 2380) = 1000 Nm 3 / h, satisfying 0 < V i ≤ V 标 , then when ΣV i = Vs, the adsorption amount of the adsorption tower A reaches the working adsorption capacity, and the actual adsorption time t 实 of the adsorption tower A = Vs / V i = V 标 *t 标 / V i = (1000 Nm 3 / h)*(8 h) / (1000 Nm 3 / h) = 8 h = t 标 ; that is, when the actual adsorption time of the adsorption tower A reaches 8 h, ΣVi =Vs, the adsorption reaches the working adsorption capacity, and then the adsorption working state is terminated, the hydrogen flow output from step (1) is switched to the adsorption tower B which is on standby after the desorption regeneration state is terminated to perform adsorption work, and at the same time, the adsorption tower C which is in the adsorption recovery state is switched to the adsorption regeneration state, and the adsorption tower A which has terminated the adsorption working state is switched to the adsorption recovery state, that is, switched to state 2;

[0078] During regeneration, due to V i =V 标 , satisfying V i ≥a%V 标 , and a = 30, then the adsorption tower B in the desorption regeneration state is desorbed and regenerated according to the normal process for up to 8 hours, and the purified hydrogen output by the adsorption tower in the adsorption working state A is distributed to 30% V 标 It is used as regeneration gas for regeneration, and the remaining part enters the product gas pipeline as product gas;

[0079] In the case of state 2, switch to state 3 according to the same method as in state 1; in the case of state 3, switch to state 1 according to the same method as in state 1; thereby realizing the alternating switching of the three towers, namely adsorption tower A, adsorption tower B and adsorption tower C, among states 1, 2 and 3.

[0080] Embodiment 2 (S2)

[0081] The purification of hydrogen produced by electrolysis is carried out according to the purification method of Example 1 (S1), and compared with Example 1, there are only the following differences:

[0082] During adsorption, when the real-time hydrogen production flow rate V i =200Nm 3 / h, according to V i =k1*(I i总 / 2380), the corresponding real-time total current I i总 =530kA, meeting 0 <V i ≤V 标 , then ΣV i = Vs, the adsorption capacity of adsorption tower A reaches the working adsorption capacity, and the actual adsorption time of adsorption tower A is t 实 =Vs / V i =V 标 *t 标 / V i =(1000Nm 3 / h)*(8h) / (200Nm 3 / h)=40h, that is, when the actual adsorption time of adsorption tower A reaches 40h, ΣV i =Vs, the adsorption reaches the working adsorption capacity, and the actual adsorption time can be extended to 40h before the adsorption working state ends;

[0083] During regeneration, since V i = 0.2V 标 satisfies V i <a%V 标 and a = 30, the adsorption tower B in the desorption regeneration state makes up the regeneration gas volume through external circulation to reach 30%V 标 and then conducts desorption regeneration for at most 8 hours.

[0084] Example 3 (S3)

[0085] Purification of electrolytic hydrogen production is carried out according to the purification method of Example 1 (S1), and compared with Example 1, there are only the following differences:

[0086] During adsorption, when the real-time total current I i总 = 3180 kA, according to V i = k1*(I i总 / 2380), the corresponding real-time hydrogen production flow rate V i = 1200 Nm 3 / h satisfies V 标 <V i ≤ 1.5V 标 . At this flow rate, the bed penetration coefficient k2 = 0.83, then ΣV i = k2Vs = 0.83*(1000 Nm 3 / h)*(8 h) = 6640 Nm 3 . When the adsorption capacity of adsorption tower A reaches the working adsorption capacity, and the actual adsorption time t 实 = ΣV i / V i = 0.83*(1000 Nm 3 / h)*(8 h) / (1200 Nm 3 / h) = 5.5 h. That is, when the actual adsorption time of adsorption tower A is shortened to 5.5 h, ΣV i = k2Vs, the adsorption reaches the working adsorption capacity, and the actual adsorption time is shortened to 5.5 h to end its adsorption working state;

[0087] During regeneration, since V i = 1.2V 标 satisfies V i ≥ a%V 标 and a = 30, the adsorption tower B in the desorption regeneration state conducts desorption regeneration for 5.5 h according to the normal process, and distributes 30%V 标 of the purified hydrogen output from the adsorption tower in the adsorption working state as the regeneration gas for desorption regeneration, and the remaining part enters the product gas pipeline as the product gas.

[0088] Example 4 (S4)

[0089] Purification for hydrogen production by electrolysis is carried out according to the purification method of Example 1 (S1), and compared with Example 1, there are only the following differences:

[0090] During adsorption, when the real-time hydrogen production flow rate V i = 100 Nm 3 / h, according to V i = k1*(I i总 / 2380), the corresponding real-time total current I i总 = 265 kA, satisfying 0 < V i ≤ V 标 , then ΣV i = Vs, the adsorption capacity of adsorption tower A reaches the working adsorption capacity, and the actual adsorption time t 实 = Vs / V i = V 标 *t 标 / V i = (1000 Nm 3 / h)*(8 h) / (100 Nm 3 / h) = 80 h, that is, when the actual adsorption time of adsorption tower A reaches 80 h, ΣV i = Vs, the adsorption reaches the working adsorption capacity, and the actual adsorption time can be extended to 80 h before ending its adsorption working state;

[0091] During regeneration, since V i = 0.1V 标 , satisfying V i < a%V 标 , and a = 30, the adsorption tower B in the desorption regeneration state makes up the regeneration gas volume through the external cycle to reach 30%V 标 and then carries out desorption regeneration for at most 8 h;

[0092] The regeneration frequency of the bed layer is reduced several times, reducing the energy consumption.

[0093] Example 5 (S5)

[0094] Purification for hydrogen production by electrolysis is carried out according to the purification method of Example 1 (S1), and compared with Example 1, there are only the following differences:

[0095] During adsorption, when the real-time hydrogen production flow rate V i = 700 Nm 3 / h, it is calculated that t 实 = 11.4 h, that is, when the actual adsorption time of adsorption tower A reaches 11.4 h, ΣV i = Vs, the adsorption reaches the working adsorption capacity, and the actual adsorption time can be extended to 80 h before ending its adsorption working state;

[0096] During regeneration, since V i = 0.7V 标 satisfies V i ≥ a%V 标 and a = 30, the adsorption tower B in the desorption regeneration state performs desorption regeneration according to the normal process for at most 8 h, and distributes a%V of the purified hydrogen output from the adsorption tower in the adsorption working state 标 as the regeneration gas for desorption regeneration, and the remaining part enters the product gas pipeline as the product gas;

[0097] The actual adsorption time of the bed layer is increased by 3.4 h, the utilization rate is increased by 40%, and the energy consumption can be reduced.

[0098] Example 6 (S6)

[0099] The purification of electrolytic hydrogen production is carried out according to the purification method of Example 1 (S1), and compared with Example 1, there are only the following differences:

[0100] During adsorption, when the real-time hydrogen production flow rate V i = 150%V 标 i.e., 1500 Nm 3 / h, it satisfies V 标 < V i ≤ 1.5V 标 , and the breakthrough coefficient k2 of the bed layer at this flow rate is 0.6, then ΣV i = k2Vs = 0.6*(1000 Nm 3 / h)*(8 h) = 4800 Nm 3 When the adsorption capacity of adsorption tower A reaches the working adsorption capacity, and the actual adsorption time t of adsorption tower A 实 = ΣV i / V i = 0.6*(1000 Nm 3 / h)*(8 h) / (1500 Nm 3 / h) = 3.2 h, that is, when the actual adsorption time of adsorption tower A is shortened to 3.2 h, ΣV i = k2Vs, the adsorption reaches the working adsorption capacity, and the actual adsorption time is shortened to 3.2 h and then its adsorption working state ends;

[0101] During regeneration, since V i = 1.5V 标 satisfies V i ≥ a%V 标 and a = 30, the adsorption tower B in the desorption regeneration state performs desorption regeneration according to the normal process for 3.2 h, and distributes a%V of the purified hydrogen output from the adsorption tower in the adsorption working state 标It is used as the regeneration gas for desorption and regeneration, and the remaining part enters the product gas pipeline as the product gas;

[0102] The regeneration power and gas velocity are correspondingly increased to shorten the regeneration time to within 3.2 h, meeting the three-tower switching, and ensuring that the purified product is still qualified under the overload condition of the purification device.

[0103] Results:

[0104] According to Examples 1-6, it can be seen that the present invention can adjust the adsorption and desorption cycle according to the actual hydrogen production flow rate, realizing the purification of electrolytic hydrogen production under a wide power fluctuation range of 0-150%.

[0105] Comparative Example 1 (D1)

[0106] The purification of electrolytic hydrogen production is carried out by using the existing three-tower non-destructive hydrogen purification. The difference from Example 4 (S1) is as follows:

[0107] In step (2), the real-time flow rate V i = 10%V 标 , that is, when it is 100 Nm 3 / h, the hydrogen flow output in step (1) is sent to the three adsorption towers respectively by the traditional adsorption and desorption process with a fixed cycle of 8 h to adsorb and remove the saturated water vapor therein, and the purified hydrogen is obtained as the product gas. The adsorption of adsorption tower A runs automatically according to the time length, stops adsorption after 8 h of adsorption, and at the same time starts regeneration; at this time, adsorption tower A does not reach the working adsorption capacity, resulting in the underutilization of adsorption tower A and frequent regeneration, with high energy consumption.

[0108] Results:

[0109] In Comparative Example 1 (D1) with a fixed adsorption and desorption cycle, adsorption tower A is not fully utilized, and there is frequent regeneration, with high energy consumption.

[0110] According to the comparison between Examples 1-6 and Comparative Example 1, it can be seen that the present invention realizes the dynamic adjustment of the adsorption and desorption cycle by correlating the current with the gas volume and performing operations with the adsorption process of the adsorption tower, can achieve purification under wide power fluctuations, and at the same time reduce the purification energy consumption.

Claims

1. A purification method for electrolytic hydrogen production adapted to wide power fluctuations, characterized in that, The purification method comprises: (1) The gas-liquid mixture coming out of the electrolytic cell of the electrolytic hydrogen production device is cooled and separated into gas and liquid, and then enters the deoxidation tower for deoxidation and output, and then condenses and separates the gas and liquid to output a hydrogen flow containing saturated water vapor; (2) The hydrogen gas outputted from step (1) is sent alternately to three adsorption towers to adsorb and remove saturated water vapor therein, thereby obtaining purified hydrogen as product gas; wherein: The three adsorption towers are alternately in an adsorption working state, a desorption regeneration state and an adsorption recovery state; the adsorption working state is to use the adsorption tower to adsorb and dehydrate the hydrogen gas flow output from step (1) to obtain purified hydrogen as the product gas; the desorption regeneration state is to use part of the purified hydrogen output from the adsorption working state as the regeneration gas to desorb and regenerate the adsorption tower that has ended the adsorption working state, desorb the water, and output a regeneration gas flow containing saturated water; the adsorption recovery state is to use the adsorption tower to adsorb and dehydrate the regeneration gas flow containing saturated water output from the desorption regeneration state to obtain purified hydrogen to enter the product gas pipeline; After the adsorption tower in the adsorption working state ends the adsorption working state, the hydrogen flow output from step (1) is switched to the adsorption tower in the end of the desorption regeneration state and the standby adsorption tower is subjected to adsorption work to switch it to the adsorption working state, and at the same time, the adsorption tower in the adsorption recovery state is switched to the adsorption regeneration state, and the adsorption tower that ends the adsorption working state is switched to the adsorption recovery state; The real-time total current I of the electrolyzer i总 and the real-time hydrogen production flow rate V i have a functional relationship of V i = k1 * (I i总 / 2380), where 0 < k1 ≤ 1; k1 is a coefficient specific to the stack; the working adsorption capacity of the adsorption tower in the adsorption working state is Vs, and Vs = V 标 * t 标 , V 标 is the rated hydrogen production flow rate of the adsorption tower in the adsorption working state, and t 标 is the rated adsorption time of the adsorption tower in the adsorption working state at V 标 ; When adsorbed, When 0 < V i ≤ V 标 it is determined that when ΣV i = Vs, the adsorption tower in the adsorption working state reaches the working adsorption capacity, then ends its adsorption working state, switches the hydrogen flow output in step (1) to the adsorption tower that has ended the desorption regeneration state and is waiting for use for adsorption work, at the same time switches the adsorption tower in the adsorption recovery state to the adsorption regeneration state, and switches the adsorption tower that has ended the adsorption working state to the adsorption recovery state; When V 标 < V i ≤ 1.5V 标 it is determined that ΣV i = k2Vs, where k2 is the penetration coefficient and 0 < k2 ≤ V 标 / V i When this occurs, the adsorption tower in the adsorption working state adsorbs until it reaches the working adsorption capacity, then ends its adsorption working state. The hydrogen gas stream output in step (1) is switched to the adsorption tower that has ended the desorption regeneration state and is on standby for adsorption work. At the same time, the adsorption tower in the adsorption recovery state is switched to the adsorption regeneration state, and the adsorption tower that has ended the adsorption working state is switched to the adsorption recovery state.

2. The purification method according to claim 1, characterized in that During regeneration, when V i ≥a%V 标 , and when 10 ≤ a ≤ 60, the adsorption tower in the desorption regeneration state undergoes desorption regeneration according to the normal process, and a%V of the purified hydrogen output from the adsorption tower in the adsorption working state is allocated 标 as the regeneration gas for desorption regeneration, and the remaining part enters the product gas pipeline as the product gas.

3. The purification method according to claim 1 or 2, characterized in that During regeneration, when V i <a%V 标 , and when 10 ≤ a ≤ 60, the amount of regeneration gas is supplemented through the outer loop to make it reach a%V 标 , and then desorption regeneration is carried out.

4. The purification method according to claim 3, wherein, The outer loop includes a buffer tank and a circulation pump. Among them, the buffer tank is respectively connected to three adsorption towers, and circulation pumps are respectively arranged on the connecting pipelines to store hydrogen gas, so that when in regeneration, in case of V i <a%V 标 occurs, the buffer tank and the circulation pump are started, and the hydrogen gas in the buffer tank is sent into the adsorption tower to be in the desorption regeneration state as the regeneration gas.

5. The purification method according to claim 4, characterized in that, The hydrogen in the buffer tank includes hydrogen product gas output by the adsorption tower in the adsorption working state.

6. The purification method according to claim 4, wherein The hydrogen in the buffer tank includes commercially available hydrogen products.

7. The purification method according to any one of claims 2-6, characterized in that, 20≤a≤30。 8. The purification method according to any one of claims 1-7, characterized in that, 0.6≤k1≤1。 9. The purification method according to any one of claims 1-8, characterized in that, 0.5≤k2≤1。