Small modular hydrogen liquefaction and intelligent filling system and method

Abstract

The invention discloses a small modular hydrogen liquefaction and intelligent filling system and method. The system is integrated in a container module and comprises a pretreatment purification module connected with a raw material hydrogen source and used for purifying raw material hydrogen, a liquefaction module connected with the pretreatment purification module and used for cooling and liquefying the purified hydrogen, and a liquid hydrogen storage and transportation and filling module connected with the liquefaction module and used for storing liquefied hydrogen, the central control module is respectively connected with the pretreatment purification module, the liquefaction module and the liquid hydrogen storage and transportation and filling module and is used for controlling all the modules. According to the system, rapid deployment is achieved through modular design, low energy consumption and low cost are achieved by optimizing operation through a prediction algorithm, the system is particularly suitable for distributed hydrogen production scenes and small and medium-sized hydrogen refueling stations, and the problems that an existing large liquefying device is not flexible and a traditional refueling station depends on external hydrogen supply are effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of small modular hydrogen liquefaction and intelligent refueling system and method, in particular to a small modular hydrogen liquefaction and intelligent refueling system and method. BACKGROUND

[0002] As a clean secondary energy, hydrogen can greatly improve the volume energy density by liquefaction (liquefaction temperature -253°C), which is an important way of efficient storage and transportation. The current large-scale hydrogen liquefaction device technology is mature, but it has the disadvantages of huge initial investment, wide land occupation, long construction period and difficulty in deployment close to distributed hydrogen sources.

[0003] Traditional hydrogen refueling stations usually rely on liquid hydrogen or high-pressure hydrogen transported from outside, with high and complex supply chain costs. For scenes with hydrogen production capacity (such as photovoltaic / wind power supporting electrolytic cells), there is a lack of an integrated solution that can directly liquefy and store fluctuating hydrogen raw materials for refueling. The existing liquefaction device is difficult to scale flexibly, and the coupling degree with the refueling system is not high, and the efficiency has optimization space.

[0004] Therefore, there is an urgent need for a small modular hydrogen liquefaction and refueling technology and equipment with low investment cost, rapid deployment, high intelligence, and flexible adaptation to different scale requirements. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a small modular hydrogen liquefaction, storage and refueling integrated system and method with compact process flow, high equipment integration, relatively low energy consumption, and convenient transportation and installation and debugging.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows: A small modular hydrogen liquefaction and intelligent refueling system is integrated in at least two containers; it includes a pretreatment purification module connected with a raw hydrogen source for purifying raw hydrogen, a liquefaction module connected with the pretreatment purification module for cooling and liquefying purified hydrogen, a liquid hydrogen storage and refueling module connected with the liquefaction module for storing liquefied hydrogen, and a central control module connected with the pretreatment purification module, the liquefaction module, and the liquid hydrogen storage and refueling module for controlling each module.

[0007] Further, the pretreatment purification module includes a buffer tank, a multi-stage filter, a purification unit and a dryer connected in sequence, the buffer tank is used to stabilize the pressure of the raw hydrogen, the multi-stage filter is used to remove particulate matter and oil mist in the raw hydrogen, the purification unit is used to purify the raw hydrogen, and the dryer is used to remove moisture in the raw hydrogen.

[0008] The purification unit is a pressure swing adsorption purification unit or a membrane separation purification unit; the dryer is a molecular sieve for removing moisture from the raw hydrogen.

[0009] Further, the liquefaction module comprises a pre-cooling stage refrigeration unit and a deep cooling stage refrigeration unit connected by pipelines, the pre-cooling stage refrigeration unit is used for pre-cooling the purified hydrogen gas from ambient temperature to a first low temperature, and the deep cooling stage refrigeration unit is used for further cooling the pre-cooled hydrogen gas and converting it into liquefied hydrogen gas; The pre-cooling stage refrigeration unit is a mixed working medium pre-cooling cycle, comprising a pre-cooling compressor, a pre-cooling after-cooler, a pre-cooling heat exchanger, a pre-cooling throttling element and a pre-cooling gas-liquid separator connected in sequence; the gas phase outlet of the pre-cooling gas-liquid separator is connected to the inlet of the pre-cooling compressor, forming a pre-cooling working medium circulation loop; the pre-cooling heat exchanger is provided with a raw hydrogen gas passage, the inlet of the raw hydrogen gas passage is used for connecting the purified hydrogen gas, and the outlet is connected to the deep cooling stage refrigeration unit; The deep cooling stage refrigeration unit is a helium reverse Brayton deep cooling cycle, comprising a main helium compressor, a regenerator, a main low-temperature heat exchanger and a turbo expander connected in sequence; the outlet of the turbo expander is connected to the inlet of the cold source side passage of the main low-temperature heat exchanger, the outlet of the cold source side passage of the main low-temperature heat exchanger is connected to the inlet of the main helium compressor through the cold source side passage of the regenerator, forming a helium working medium circulation loop; the inlet of the heat source side passage of the main low-temperature heat exchanger is connected to the outlet of the raw hydrogen gas passage of the pre-cooling heat exchanger, used for receiving the hydrogen gas that has been pre-cooled, and the outlet of the heat source side passage of the main low-temperature heat exchanger is used for outputting the liquefied hydrogen gas.

[0010] Further, the pre-cooling throttling element is a J-T valve, the pre-cooling heat exchanger and / or the main low-temperature heat exchanger and / or the regenerator is a plate-fin heat exchanger, and the main helium compressor is an oil-free compressor; The heat source side passage of the main low-temperature heat exchanger is integrated with a primary-secondary hydrogen conversion catalytic bed, the catalytic bed is filled with iron hydroxide or a nickel-based catalyst, used for catalyzing the conversion of primary hydrogen to secondary hydrogen during the liquefaction of hydrogen gas; The deep cooling stage refrigeration unit further comprises a helium blower located between the outlet of the cold side passage of the regenerator and the inlet of the main helium compressor; The pre-cooling stage refrigeration unit pre-cools the hydrogen gas from ambient temperature to -193°C ± 5°C, and the deep cooling stage refrigeration unit further cools the pre-cooled hydrogen gas and liquefies it to below -253°C.

[0011] Further, the liquid hydrogen storage and filling module comprises at least one liquid hydrogen storage tank and a filling machine connected to the liquid hydrogen storage tank, the liquid hydrogen storage tank is used for storing liquefied hydrogen gas, and the filling machine is used for pressurizing the liquefied hydrogen gas and injecting the pressurized hydrogen gas into an object to be filled; The liquid hydrogen storage and transportation and filling module further comprises an evaporated gas recovery pipeline connected to the liquid hydrogen storage tank and connected to the pretreatment purification module and the liquefaction module, and the evaporated gas recovery pipeline is used to recover the evaporated gas generated in the liquid hydrogen storage tank due to heat invasion and recycle the evaporated gas to the pretreatment purification module and the liquefaction module for recycling; The filling machine comprises a filling pump and a filling gun connected to each other, and further comprises a mass flow meter, a low-temperature hose, a pull-off valve and a priority control system connected to the filling pump and the filling gun; The pressurization mode of the filling pump comprises liquid hydrogen pressurization and gas hydrogen pressurization, the liquid hydrogen pressurization is liquid hydrogen pressurized to the required pressure of the object to be filled, and the gas hydrogen pressurization is liquid hydrogen pressurized to normal temperature hydrogen.

[0012] Further, the pretreatment purification module is installed in the first container, and the liquefaction module is installed in the second container.

[0013] Further, the central control module comprises a data acquisition and monitoring control system or a distributed control system as an upper computer, and a programmable logic controller as a lower computer.

[0014] A small modular hydrogen liquefaction and intelligent filling method, comprising the following steps: S1, the pretreatment purification module buffers and stabilizes the raw hydrogen, multi-stage filters, purifies and deeply dries the raw hydrogen to obtain purified hydrogen; S2, the liquefaction module pre-cools the purified hydrogen to a first low temperature, and then deeply cools the hydrogen to liquefy the hydrogen after deep cooling and separate the liquefied hydrogen; S3, the liquefied hydrogen is stored in the liquid hydrogen storage tank of the liquid hydrogen storage and transportation and filling module, and the evaporated gas generated in the liquid hydrogen storage tank is introduced back to the pretreatment purification module and the liquefaction module for recycling; S4, the central control module controls and optimizes the liquid hydrogen storage and transportation and filling module to directly fill or pressurize and fill the liquefied hydrogen to the object to be filled based on a prediction algorithm.

[0015] Further, the prediction algorithm comprises: S41, collecting original data and cleaning, normalizing and feature processing the original data to obtain pretreatment data; S42, based on the pretreatment data, using a trained prediction model to predict the prediction results including hydrogen filling demand, renewable energy power generation and power grid price in a future specified period; S43, taking the minimum system comprehensive operation cost as the target, based on the current system state and the prediction results, generating control instructions for the liquefaction module through a reinforcement learning algorithm; S44, issuing the control instructions to the liquefaction module for execution, and rolling out steps S41 to S43 at a preset time period, and dynamically adjusting the control instructions according to the deviation between the prediction results and the actual data corresponding to the prediction results.

[0016] Further, the original data includes environmental data, energy data, operation data and equipment state data; The prediction model includes a short-term load prediction model, a renewable energy power generation prediction model and a power price prediction model; the short-term load prediction model is a long short-term memory network or a Transformer time series model, which predicts the hydrogen refueling demand every hour within 24-72 hours in the future through historical refueling data, date type, weather condition and nearby area activity information; the renewable energy power generation prediction model is a time series prediction model, which predicts the renewable energy power generation power curve within 24 hours in the future through meteorological forecast data; and the power price prediction model predicts the time-of-use power price curve within 24 hours in the future through public data of the power market; The reinforcement learning algorithm is a proximal policy optimization algorithm or a deep deterministic policy gradient algorithm; The control instruction is used to realize one or more of the following strategies: When the power price is at a low valley and / or the renewable energy power generation power is abundant, the instruction core liquefaction module is instructed to increase the operation power for energy storage; Before the predicted hydrogen refueling demand peak arrives, the instruction core liquefaction module is instructed to increase the operation power in advance, so that the liquid level of the liquid hydrogen storage tank reaches a safety upper limit; When there is no hydrogen refueling demand and the power price is at a peak, the instruction core liquefaction module is instructed to enter a low-power standby mode.

[0017] Compared with the prior art, the present application has the following beneficial effects: The present application provides a small, modular and highly integrated system and process flow integrating hydrogen liquefaction, storage, gasification and refueling functions, which is particularly suitable for distributed hydrogen sources (such as renewable energy electrolysis water hydrogen production sites) or small and medium-sized hydrogen refueling stations.

[0018] The modules of the present application are integrated in a container, realizing in-plant manufacturing, testing and debugging, greatly reducing on-site construction work and time, reducing cost, and being flexible to transport to any location in the world for rapid deployment. The modular design enables dangerous processes to be completed in a controlled factory environment, and the site is only the docking between modules.

[0019] The present application seamlessly integrates liquefaction, storage and refueling functions, is suitable for matching renewable energy electrolysis water hydrogen production, solves the volatility problem, realizes "production-liquefaction-storage-refueling" integration, and is an ideal solution for building distributed hydrogen infrastructure. The present application also realizes energy efficiency optimization and unattended operation through the central control module, reducing operating costs and dependence on professional operators.

[0020] The cascade mode of the mixed working medium pre-cooling + helium reverse Brayton cryogenic cycle adopted by the application follows the thermodynamic cascade utilization principle, lets the refrigeration cycles in different temperature zones focus on their most efficient working intervals (the mixed working medium is responsible for medium and high temperature, and the reverse Brayton is responsible for deep low temperature), and maximizes the recovery of cold energy through regenerative means, so that the unit liquefaction energy consumption of the whole system can be reduced to a lower level. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The figure is a structural block diagram of the system of the application.

[0022] Figure 2 The figure is a structural block diagram of the pre-treatment purification module.

[0023] Figure 3 The figure is a structural block diagram of the liquefaction module.

[0024] Figure 4 The figure is a structural block diagram of the pre-cooling section refrigeration unit.

[0025] Figure 5 The figure is a structural block diagram of the deep cooling section refrigeration unit. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the application clearer and more apparent, the application will be further described in detail below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0027] In the description of the application, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and therefore they cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore they cannot be understood as limiting the application. In addition, the terms "first", "second" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0028] In the description of the present application, it should be noted that unless otherwise expressly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; of course, it can also be mechanically connected, or electrically connected; in addition, it can also be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0029] As Figure 1 shown, a small modular hydrogen liquefaction and intelligent filling system of the present application is integrated in at least two containers; including a pretreatment purification module connected with a raw hydrogen source for purifying raw hydrogen, a liquefaction module connected with the pretreatment purification module for cooling and liquefying purified hydrogen, a liquid hydrogen storage and filling module connected with the liquefaction module for storing liquefied hydrogen, and a central control module connected with the pretreatment purification module, the liquefaction module and the liquid hydrogen storage and filling module respectively for controlling each module. The raw hydrogen is purified by the pretreatment purification module to obtain purified hydrogen, and then the liquefaction module is used to prepare liquefied hydrogen and store it in the liquid hydrogen storage and filling module, and finally the liquefied hydrogen is filled into the object to be filled according to the actual filling demand.

[0030] The filling system of the present application is a small, modular, highly integrated system that integrates hydrogen liquefaction, storage, gasification and filling functions, and is particularly suitable for distributed hydrogen sources (such as renewable energy electrolytic water hydrogen production sites) or small and medium-sized hydrogen filling stations. The modules are integrated in the container, which realizes the manufacturing, testing and debugging in the factory, greatly reduces the site construction work and time, reduces the cost, and can be flexibly transported to any location in the world for rapid deployment.

[0031] In some embodiments of the present application, as Figure 2 shown, the pretreatment purification module includes a buffer tank, a multi-stage filter, a purification unit and a dryer connected in sequence, the buffer tank is used to stabilize the pressure of the raw hydrogen, the multi-stage filter is used to remove particulate matter and oil mist in the raw hydrogen, the purification unit is used to purify the raw hydrogen, and the dryer is used to remove moisture in the raw hydrogen. Specifically, the raw hydrogen with a pressure of 1.0-3.0 MPa and a purity of about 99.5% is buffered and stabilized by the buffer tank, and then purified to more than 99.999% by multi-stage filtration of the multi-stage filter and pressure swing adsorption of the purification unit, while the water content is reduced to less than 1 ppm by deep drying of the dryer. The purification unit is a pressure swing adsorption purification unit or a membrane separation purification unit; the dryer uses molecular sieve to remove moisture from the raw hydrogen.

[0032] In some embodiments of the present application, as Figure 3As shown, the liquefaction module includes a pre-cooling stage refrigeration unit and a deep cooling stage refrigeration unit connected by pipelines, the pre-cooling stage refrigeration unit is used for pre-cooling the purified hydrogen gas from ambient temperature to a first low temperature, and the deep cooling stage refrigeration unit is used for further cooling the pre-cooled hydrogen gas and converting it into liquefied hydrogen gas. The present application adopts a cascade refrigeration process of pre-cooling + deep cooling, aiming at efficiently and stably cooling hydrogen gas from normal temperature to a liquefaction temperature of -253°C.

[0033] As shown in the figure, Figure 4 The pre-cooling stage refrigeration unit is a mixed working medium pre-cooling cycle, including a pre-cooling compressor, a pre-cooling after-cooler, a pre-cooling heat exchanger, a pre-cooling throttling element and a pre-cooling gas-liquid separator connected in sequence; the gas phase outlet of the pre-cooling gas-liquid separator is connected to the inlet of the pre-cooling compressor, forming a pre-cooling working medium circulation loop; the pre-cooling heat exchanger is provided with a raw hydrogen gas passage, the inlet of the raw hydrogen gas passage is used for connecting the purified hydrogen gas, and the outlet is connected to the deep cooling stage refrigeration unit. The specific process of pre-cooling is as follows: the pre-cooling compressor provides power for the entire pre-cooling cycle, which sucks in and compresses the low-temperature and low-pressure mixed working medium to make it into a high-temperature and high-pressure gas. The pre-cooling after-cooler cools the high-temperature and high-pressure working medium gas from the pre-cooling compressor into low-temperature liquid-phase mixed working medium close to ambient temperature, which is further pre-cooled by an internal cold source through a passage of the pre-cooling heat exchanger, and then is converted into a low-temperature and low-pressure gas-liquid two-phase mixture after throttling expansion through the pre-cooling throttling element. The gas-liquid two-phase mixture enters the pre-cooling gas-liquid separator for separation, and the separated liquid-phase working medium (cold source) enters the pre-cooling heat exchanger to be converted into low-pressure gas. The separated gas-phase working medium and the evaporated low-pressure gas return to the pre-cooling compressor inlet together to complete the cycle. At the same time, the purified high-pressure hydrogen gas flows into the raw hydrogen gas passage of the pre-cooling heat exchanger, is cooled to the target temperature (about -193°C) by the separated liquid-phase working medium (cold source), and obtains pre-cooled hydrogen gas, which is then delivered to the deep cooling stage refrigeration unit through the raw hydrogen gas passage outlet.

[0034] The pre-cooling stage refrigeration unit is responsible for pre-cooling the purified high-pressure hydrogen gas (~25°C) from ambient temperature to about -193°C (-193°C ± 5°C). In this temperature range, most of the sensible heat of hydrogen gas is removed. The mixed working medium used is a non-azeotropic mixed working medium (such as a mixture of nitrogen, methane, propane, etc.), which is the key to the high efficiency of the pre-cooling stage refrigeration unit. It has a temperature glide when evaporating, which can achieve better temperature matching with the cooling curve of hydrogen gas, reduce the irreversible loss of heat exchange, and thus significantly improve the efficiency.

[0035] As shown in the figure, Figure 5As shown, the cryogenic refrigeration unit is a helium reverse Brayton cryogenic cycle, including a main helium compressor, a regenerator, a main cryogenic heat exchanger and a turbo-expander connected in sequence; the outlet of the turbo-expander is connected with the inlet of the cold source side channel of the main cryogenic heat exchanger, and the outlet of the cold source side channel of the main cryogenic heat exchanger is connected to the inlet of the main helium compressor through the cold source side channel of the regenerator, forming a helium working medium circulation loop; the inlet of the heat source side channel of the main cryogenic heat exchanger is connected with the outlet of the raw hydrogen gas channel of the pre-cooling heat exchanger for receiving hydrogen gas that has been pre-cooled, and the outlet of the heat source side channel of the main cryogenic heat exchanger is used for outputting liquefied hydrogen gas. The specific process of the cryogenic is as follows: low-pressure helium gas enters the main helium compressor and is compressed into high-temperature and high-pressure helium gas. The high-temperature and high-pressure helium gas flows into the heat source side of the regenerator and is pre-cooled into high-pressure helium gas by the backflow of cold helium gas. The high-pressure helium gas enters the main cryogenic heat exchanger and is further cooled into low-temperature helium gas, which then enters the turbo-expander for isentropic expansion, and at the same time, the output power is converted into super-low-temperature and low-pressure helium gas. The super-low-temperature and low-pressure helium gas flows back into the cold source side of the main cryogenic heat exchanger and cools the pre-cooled hydrogen gas output from the pre-cooling refrigeration unit as a cold source, and the pre-cooled hydrogen gas is converted into liquefied hydrogen gas. The super-low-temperature and low-pressure helium gas absorbs heat and its temperature rises to cold helium gas. The cold helium gas enters the cold source side of the regenerator, pre-cools the high-temperature and high-pressure helium gas flowing in the positive direction, and its temperature further rises to low-pressure helium gas and finally returns to the inlet of the main helium compressor, then is compressed, and completes a closed cycle.

[0036] The cryogenic refrigeration unit is responsible for further cooling the hydrogen gas pre-cooled to -193°C to its boiling point (-252.8°C) and liquefying it. The cryogenic refrigeration unit has high isentropic expansion efficiency in the deep low temperature range, which is the preferred method for producing cryogenic cold energy.

[0037] Preferably, the pre-cooling throttling element is a J-T valve, the pre-cooling heat exchanger and / or the main cryogenic heat exchanger and / or the regenerator is a plate-fin heat exchanger, and the main helium compressor is an oil-free compressor. The plate-fin heat exchanger has a huge heat transfer area in a unit volume and extremely high heat transfer efficiency, so it can integrate a large heat exchange network into a limited container space, realizing the miniaturization and modularization of the device. The oil-free compressor can adapt to the characteristics of different working media and avoid the blockage of lubricating oil into the low-temperature system.

[0038] Preferably, a primary-secondary hydrogen conversion catalyst bed is integrated in the heat source side channel of the main cryogenic heat exchanger, and the catalyst bed is filled with iron hydroxide or nickel-based catalyst, which is used to catalyze the conversion of normal hydrogen to para-hydrogen during the liquefaction of hydrogen gas and take away the released conversion heat. The primary-secondary hydrogen conversion catalyst bed realizes efficient step utilization of cold energy and ensures that the output is stable para-hydrogen liquid, avoiding the increase of evaporation loss during storage due to the exothermic reaction of primary-secondary conversion.

[0039] Preferably, the cryogenic section refrigeration unit further comprises a helium blower between the outlet of the cold side channel of the recuperator and the inlet of the main helium compressor. The helium blower is used to overcome the fluid resistance in the circulation loop and deliver the low-pressure helium gas back to the inlet of the main helium compressor.

[0040] In some embodiments of the present application, the liquid hydrogen storage and dispensing module comprises at least one liquid hydrogen tank and a dispenser connected to the liquid hydrogen tank. The liquid hydrogen tank (vacuum multi-layer insulated, with an effective volume usually between 5m³ and 50m³) is used to store liquefied hydrogen gas, and the dispenser is used to pressurize the liquefied hydrogen gas and inject the pressurized hydrogen gas into an object to be filled (e.g. a vehicle-mounted liquid hydrogen storage cylinder of an automobile). The liquid hydrogen storage and dispensing module further comprises an evaporation gas recovery pipeline connected from the liquid hydrogen tank to the pretreatment purification module and the liquefaction module, which is used to recover the evaporation gas generated by heat intrusion in the liquid hydrogen tank and recycle the evaporation gas to the pretreatment purification module and the liquefaction module for recycling. The dispenser comprises a connected dispensing pump and a dispensing gun, and further comprises a mass flow meter, a cryogenic hose, a pull-off valve and a priority control system connected to the dispensing pump and the dispensing gun. The pressurization mode of the dispensing pump includes liquid hydrogen pressurization and gas hydrogen pressurization. The liquid hydrogen pressurization is to pressurize the liquid hydrogen to the required pressure (e.g. 35MPa or 70MPa required by a vehicle-mounted liquid hydrogen storage cylinder of an automobile) of the object to be filled, and the gas hydrogen pressurization is to pressurize the liquid hydrogen to normal temperature hydrogen gas. The gas hydrogen pressurization is realized by a vaporizer installed on the dispensing pump, which is preferably an air-cooled or water-bath type vaporizer. The liquid hydrogen storage and dispensing module performs a communication protocol in accordance with SAE J2601 standard for dispensing.

[0041] In some embodiments of the present application, the pretreatment purification module is installed in a first container, and the liquefaction module is installed in a second container. The liquid hydrogen storage and dispensing module is arranged outdoors for hydrogen filling, and the central control module is arranged at the hydrogen filling site and integrated with the pretreatment purification module or the liquefaction module in one container, or separately integrated in one container, or reasonably arranged according to actual needs.

[0042] In some embodiments of the present application, the central control module comprises a data acquisition and monitoring control system or a distributed control system as an upper computer, and a programmable logic controller as a lower computer. The lower computer is directly connected to the sensors and actuators arranged on each module, and is responsible for performing fast and reliable specific control tasks and safety interlocking. The upper computer provides a graphical human-machine interface for the operator to remotely monitor the running state of the entire system, modify parameters, view historical data and alarm information.

[0043] A small modular hydrogen liquefaction and intelligent dispensing method of the present application comprises the following steps: S1, the pretreatment purification module buffers and stabilizes the pressure of the raw hydrogen gas, multi-stage filters, purifies and deeply dries the raw hydrogen gas to obtain purified hydrogen gas; S2, the liquefaction module pre-cools the purified hydrogen to a first low temperature, and after deep cooling, liquefies the deep-cooled hydrogen and separates the liquefied hydrogen obtained after separation; S3, the liquefied hydrogen is stored in the liquid hydrogen storage tank of the liquid hydrogen storage and filling module, and the evaporated gas generated in the liquid hydrogen storage tank is introduced back to the pretreatment and purification module and the liquefaction module for recycling; S4, the central control module controls and optimizes the liquid hydrogen storage and filling module to directly fill or pressurize and fill the liquefied hydrogen after gasification to the object to be filled based on a prediction algorithm.

[0044] In some embodiments of the present application, the prediction algorithm comprises: S41, collecting raw data and performing cleaning, normalization and feature processing on the raw data to obtain preprocessed data; S42, based on the preprocessed data, using a trained prediction model to predict the prediction results including hydrogen filling demand, renewable energy power generation and electricity price in a future specified period; S43, taking the minimum system comprehensive operation cost as the target, based on the current system state and the prediction results, generating control instructions for the liquefaction module through reinforcement learning algorithm; S44, issuing the control instructions to the liquefaction module for execution, and rolling out steps S41 to S43 at a predetermined time period, and dynamically adjusting the control instructions according to the deviation between the prediction results and the actual data corresponding to the prediction results.

[0045] The raw data includes environmental data, energy data, operation data and equipment state data. The environmental data includes environmental temperature, environmental humidity and atmospheric pressure. The energy data includes real-time electricity price (if connected to the grid), current power generation of renewable energy (such as photovoltaic and wind power) and short-term predicted power. The operation data includes historical filling records (time, filling amount, vehicle type), current filling station vehicle queuing situation, liquid level and pressure of the liquid hydrogen storage tank. The equipment state data includes power, speed, inlet and outlet pressure and temperature of each compressor in the liquefaction module, speed and efficiency of the turbo expander, and temperature and pressure sensor readings of each key node.

[0046] The prediction model includes a short-term load prediction model, a renewable energy power generation prediction model and an electricity price prediction model. The short-term load prediction model is a long short-term memory network or a Transformer time series model, which predicts the hydrogen filling demand every hour in the future 24-72 hours through historical filling data, date type, weather condition and nearby area activity information. The renewable energy power generation prediction model is a time series prediction model, which predicts the renewable energy power generation power curve in the future 24 hours through weather forecast data. The electricity price prediction model predicts the time-of-use electricity price curve in the future 24 hours through public data of the electricity market.

[0047] With the lowest system comprehensive operation cost as the target, while taking into account the equipment life (such as reducing the number of compressor start-stop), and based on the current system state (current time, liquid level of liquid hydrogen storage tank, ambient temperature, real-time electricity price, renewable energy power generation), and the prediction results, the control instruction for the liquefaction module is generated through the reinforcement learning algorithm. The reinforcement learning algorithm is a proximal policy optimization algorithm or a deep deterministic policy gradient algorithm.

[0048] The control instruction is used to implement one or more of the following strategies: When the electricity price is at a low valley and / or the renewable energy power generation is abundant, instruct the core liquefaction module to increase the operation power for energy storage; Before the predicted peak of hydrogen refueling demand arrives, instruct the core liquefaction module to increase the operation power in advance, so that the liquid level of the liquid hydrogen storage tank reaches the safety upper limit; When there is no hydrogen refueling demand and the electricity price is at a peak, instruct the core liquefaction module to enter a low-power standby mode.

[0049] Preferably, the preset time period is 15-30 minutes. The prediction algorithm of the present application upgrades the traditional rule-based control to data-driven intelligent prediction and optimization control, and can actively respond to the volatility of renewable energy and refueling demand, rather than passive response, thereby significantly reducing the operation cost of the system and improving the economy under the premise of ensuring reliability.

[0050] Finally, it should be noted that: the above embodiments are only the preferred embodiments of the present application for describing the technical solutions of the present application, but not limiting them, and of course, not limiting the patent scope of the present application; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part 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 embodiments of the present application; that is, any modification or embellishment made in the spirit of the main design idea and spirit of the present application, which still solves the technical problems consistent with the present application, should be included in the protection scope of the present application; in addition, the technical solutions of the present application are directly or indirectly applied to other related technical fields, which are also included in the patent protection scope of the present application.

Claims

1. A small modular hydrogen liquefaction and smart filling system, characterized in that, The integrated at least two containers; including a pretreatment purification module connected with the raw hydrogen source for purifying raw hydrogen, a liquefaction module connected with the pretreatment purification module for cooling and liquefying purified hydrogen, a liquid hydrogen storage and filling module connected with the liquefaction module for storing liquefied hydrogen, and a central control module connected with the pretreatment purification module, the liquefaction module and the liquid hydrogen storage and filling module respectively for controlling each module.

2. The small modular hydrogen liquefaction and smart filling system of claim 1, wherein, The pretreatment purification module comprises a buffer tank, a multi-stage filter, a purification unit and a dryer connected in sequence, the buffer tank is used for stabilizing the pressure of raw hydrogen, the multi-stage filter is used for removing particulate matter and oil mist in raw hydrogen, the purification unit is used for purifying raw hydrogen, and the dryer is used for removing moisture in raw hydrogen. The purification unit is a pressure swing adsorption purification unit or a membrane separation purification unit; the dryer uses a molecular sieve to remove moisture from raw hydrogen.

3. The small modular hydrogen liquefaction and smart filling system of claim 2, wherein, The liquefaction module comprises a pre-cooling section refrigeration unit and a deep cooling section refrigeration unit connected by pipelines, the pre-cooling section refrigeration unit is used for pre-cooling purified hydrogen from ambient temperature to a first low temperature, and the deep cooling section refrigeration unit is used for further cooling the pre-cooled hydrogen and converting it into liquefied hydrogen; The pre-cooling section refrigeration unit is a mixed working medium pre-cooling cycle, comprising a pre-cooling compressor, a pre-cooling after-cooler, a pre-cooling heat exchanger, a pre-cooling throttling element and a pre-cooling gas-liquid separator connected in sequence; the gas phase outlet of the pre-cooling gas-liquid separator is connected to the inlet of the pre-cooling compressor to form a pre-cooling working medium circulation loop; the pre-cooling heat exchanger is provided with a raw hydrogen passage, the inlet of the raw hydrogen passage is used for connecting the purified hydrogen, and the outlet is connected to the deep cooling section refrigeration unit; The deep cooling section refrigeration unit is a helium reverse Brayton deep cooling cycle, comprising a main helium compressor, a regenerator, a main low-temperature heat exchanger and a turbo expander connected in sequence; the outlet of the turbo expander is connected to the cold source side passage inlet of the main low-temperature heat exchanger, the cold source side passage outlet of the main low-temperature heat exchanger is connected to the inlet of the main helium compressor through the cold source side passage of the regenerator to form a helium working medium circulation loop; the hot source side passage inlet of the main low-temperature heat exchanger is connected to the raw hydrogen passage outlet of the pre-cooling heat exchanger for receiving hydrogen that has been pre-cooled, and the hot source side passage outlet of the main low-temperature heat exchanger is used for outputting liquefied hydrogen.

4. The small modular hydrogen liquefaction and smart filling system of claim 3, wherein, The pre-cooling throttling element is a J-T valve, the pre-cooling heat exchanger and / or the main low-temperature heat exchanger and / or the regenerator is a plate-fin heat exchanger, and the main helium compressor is an oil-free compressor; The hot source side passage of the main low-temperature heat exchanger is integrated with a primary-secondary hydrogen conversion catalytic bed, the catalytic bed is filled with iron hydroxide or a nickel-based catalyst, and is used for catalyzing the conversion of primary hydrogen to secondary hydrogen during the liquefaction of hydrogen; The deep cooling section refrigeration unit further comprises a helium blower located between the cold side passage outlet of the regenerator and the inlet of the main helium compressor; The pre-cooling section refrigeration unit pre-cools hydrogen from ambient temperature to -193°C ± 5°C, and the deep cooling section refrigeration unit further cools the pre-cooled hydrogen and liquefies it to below -253°C.

5. The small modular hydrogen liquefaction and smart filling system of claim 1, wherein, The liquid hydrogen storage and filling module comprises at least one liquid hydrogen storage tank and a filling machine connected with the liquid hydrogen storage tank, the liquid hydrogen storage tank is used for storing liquefied hydrogen, and the filling machine is used for pressurizing the liquefied hydrogen and injecting the pressurized hydrogen into an object to be filled; The liquid hydrogen storage and transportation and filling module further comprises an evaporated gas recovery pipeline connected from the liquid hydrogen storage tank to the pretreatment purification module and the liquefaction module, and the evaporated gas recovery pipeline is used to recover the evaporated gas generated in the liquid hydrogen storage tank due to heat invasion and recycle the evaporated gas to the pretreatment purification module and the liquefaction module for recycling; The filling machine comprises a filling pump and a filling gun connected with each other, and further comprises a mass flow meter, a low-temperature hose, a pull-off valve and a priority control system connected with the filling pump and the filling gun; The pressurization mode of the filling pump comprises liquid hydrogen pressurization and gas hydrogen pressurization, the liquid hydrogen pressurization is liquid hydrogen pressurized to the required pressure of the object to be filled, and the gas hydrogen pressurization is hydrogen gas pressurized to normal temperature.

6. The small modular hydrogen liquefaction and smart filling system of claim 1, wherein, The pretreatment purification module is installed in the first container, and the liquefaction module is installed in the second container.

7. The small modular hydrogen liquefaction and smart filling system of claim 1, wherein, The central control module comprises a data acquisition and monitoring control system or a distributed control system as an upper computer and a programmable logic controller as a lower computer.

8. A small modular hydrogen liquefaction and smart filling method, characterized in that, The method comprises the following steps: S1, the pretreatment purification module buffers, stabilizes pressure, filters, purifies and deeply dries the raw hydrogen gas to obtain purified hydrogen gas; S2, the liquefaction module pre-cools the purified hydrogen gas to a first low temperature, deeply cools the hydrogen gas, liquefies the deeply cooled hydrogen gas, and separates the liquefied hydrogen gas obtained after liquefaction; S3, the liquefied hydrogen gas is stored in the liquid hydrogen storage tank of the liquid hydrogen storage and transportation and filling module, and the evaporated gas generated in the liquid hydrogen storage tank is introduced back to the pretreatment purification module and the liquefaction module for recycling; S4, the central control module controls and optimizes the liquid hydrogen storage and transportation and filling module to directly fill or pressurize and fill the liquefied hydrogen gas to the object to be filled based on a prediction algorithm.

9. A small modular hydrogen liquefaction and smart filling method according to claim 8, characterized in that, The prediction algorithm comprises: S41, collecting original data and performing cleaning, normalization and feature processing on the original data to obtain pretreatment data; S42, based on the pretreatment data, using a trained prediction model to predict the prediction results including hydrogen filling demand, renewable energy power generation and electricity price in a future specified period; S43, taking the minimum system comprehensive operation cost as the target, based on the current system state and the prediction results, generating control instructions for the liquefaction module through a reinforcement learning algorithm; S44, issuing the control instructions to the liquefaction module for execution, and rolling out steps S41 to S43 at a preset time period, and dynamically adjusting the control instructions according to the deviation between the prediction results and the actual data corresponding to the prediction results.

10. The method of claim 9, wherein, The original data comprises environmental data, energy data, operation data and equipment state data; The prediction model comprises a short-term load prediction model, a renewable energy power generation prediction model and an electricity price prediction model; the short-term load prediction model is a long short-term memory network or a Transformer time series model, which predicts the hydrogen filling demand every hour in the next 24-72 hours through historical filling data, date type, weather condition and nearby area activity information; the renewable energy power generation prediction model is a time series prediction model, which predicts the renewable energy power generation power curve in the next 24 hours through weather forecast data; the electricity price prediction model predicts the time-of-use electricity price curve in the next 24 hours through public data of the electricity market; The reinforcement learning algorithm is a proximal policy optimization algorithm or a deep deterministic policy gradient algorithm. The control instruction is used to implement one or more of the following strategies: When the electricity price is low and / or the renewable energy power generation is abundant, the instruction core liquefaction module increases the operation power for energy storage; Before the predicted peak of hydrogen refueling demand, the instruction core liquefaction module increases the operation power in advance, so that the liquid level of the liquid hydrogen storage tank reaches the safety upper limit; When there is no hydrogen refueling demand and the electricity price is high, the instruction core liquefaction module enters a low-power standby mode.

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