KR20230096182A - Liquid hydrogen fueling system - Google Patents

Abstract

Disclosed is a liquid hydrogen fueling system, which can reduce energy consumed for increasing the temperature of hydrogen. The liquid hydrogen fueling system according to one embodiment of the present invention comprises: a storage tank which stores liquid hydrogen; a high-pressure pump which provides pumping power for transferring the hydrogen stored in the storage tank; a catalytic combustor which generates heat by using boil-off gas generated from the storage tank as a fuel source and then heats the hydrogen branching from an output terminal of the high-pressure pump; a heater which additionally heats the hydrogen heated by the catalytic combustor at first; a buffer tank which temporarily stores the hydrogen heated by the heater; a cooler which cools, as the hydrogen stored in the buffer tank and the hydrogen branching from the high-pressure pump are mixed in a mixture point, the hydrogen introduced from the mixture point; and a dispenser which injects the cooled hydrogen into an external hydrogen tank.

Description

Liquid hydrogen charging system {LIQUID HYDROGEN FUELING SYSTEM}

The present invention relates to a liquid hydrogen charging system, and more particularly, to a new type of liquid hydrogen charging station system capable of efficiently converting hydrogen stored in a liquid state into gaseous hydrogen under a predetermined condition.

As hydrogen fuel cell technology is commercialized in earnest as a clean energy technology, hydrogen charging stations for charging hydrogen are emerging as essential infrastructure facilities.

The hydrogen charging station system converts hydrogen from an ultra-low temperature liquid state to a gas state and injects it into an external tank through a dispenser, and converts the pressure and temperature conditions to a predetermined state while storing hydrogen in an ultra-high pressure gas state It is distinguished by a gas filling station system that injects into an external tank.

The liquefied hydrogen charging station system has the advantage of requiring only 1/20 less of the facility area than gaseous hydrogen charging stations, being able to implement more than three times the charging capacity, and promoting safety with normal pressure supply and storage pressure. In the mid- to long-term, it is expected that the proportion of liquefied hydrogen filling station systems will increase.

However, the liquefied hydrogen filling station system converts liquid hydrogen stored in a tank at a pressure of 2 to 3 bar and a temperature of -250 ° C into gaseous hydrogen at a pressure of 700 bar and a temperature of -40 ° C. It has to be supplied externally.

Accordingly, the need for a new type of liquefied hydrogen filling station system capable of efficiently converting liquid hydrogen into gaseous hydrogen under predetermined conditions has emerged.

Japanese Patent Publication No. 2016-084940

The present invention has been made to solve the above problems, and an object of the present invention is to provide a liquefied hydrogen charging system capable of efficiently converting cryogenic liquid hydrogen into gaseous hydrogen suitable for charging an external tank. are doing

The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

A liquefied hydrogen filling system according to an embodiment of the present invention for achieving the above object is a storage tank for storing liquid hydrogen, a high-pressure pump for providing pumping power for transferring the hydrogen stored in the storage tank, the A catalytic combustor that heats the hydrogen branched from the output end of the high-pressure pump by generating heat from the boil-off gas generated in the storage tank as a fuel source, a heater that additionally heats the hydrogen primarily heated in the catalytic combustor, and the heater A buffer tank for temporarily storing heated hydrogen, a cooler in which the hydrogen stored in the buffer tank and the hydrogen branched from the high-pressure pump are mixed at a mixing point, and a cooler for cooling the hydrogen introduced at the mixing point, and an external hydrogen tank for storing the cooled hydrogen. Includes a dispenser to inject into.

According to an embodiment of the present invention, a sensing unit for sensing the temperature of hydrogen mixed at the mixing point, a first valve branched from the rear end of the high pressure pump and controlling the flow rate flowing into the mixing point, and a rear end of the high pressure pump It may further include a second valve that is branched and controls flow rate flowing into the catalytic combustor, and a control unit that controls open/close states of the first valve and the second valve.

According to an embodiment of the present invention, the control unit may generate a control signal for opening the first valve and closing the second valve when the temperature of the hydrogen mixed at the mixing point is higher than the target temperature. .

According to an embodiment of the present invention, the control unit may generate a control signal for closing the first valve and opening the second valve when the temperature of the hydrogen mixed at the mixing point is lower than a target temperature. .

According to one embodiment of the present invention, a generator may be disposed between the high-pressure pump and the catalytic combustor to generate electric energy required to drive the heater using cold heat energy.

According to one embodiment of the present invention, the generator, a pump for pressurizing the working fluid, an evaporator for increasing the temperature and vaporizing by applying heat to the working fluid, rotating the rotor when the working fluid passes through to convert kinetic energy into electricity It may include a turbine for converting energy and a condenser for cooling the working fluid and converting the working fluid into a liquid through heat exchange between the working fluid and hydrogen branched from the pump and flowing to the catalytic combustor.

According to one embodiment of the present invention, an additional heat exchanger disposed to allow heat exchange between the working fluid passing through the pump and the working fluid passing through the turbine may be further included.

A liquid hydrogen filling system according to another embodiment of the present invention includes a storage tank for storing hydrogen in a liquid state, a high-pressure pump for providing pumping power to transfer hydrogen stored in the storage tank, and a space between the high-pressure pump and the heater. A generator for generating electric energy required to drive the heater by using cold heat energy, a heater for additionally heating the hydrogen primarily heated through heat exchange in the generator, and a buffer for temporarily storing the hydrogen heated in the heater. A tank, hydrogen stored in the buffer tank and hydrogen branched from the high-pressure pump are mixed at a mixing point, a cooler for cooling the hydrogen introduced at the mixing point, and a dispenser for injecting the cooled hydrogen into an external hydrogen tank.

According to one embodiment of the present invention, the generator, a pump for pressurizing the working fluid, an evaporator for increasing the temperature and vaporizing by applying heat to the working fluid, rotating the rotor when the working fluid passes through to convert kinetic energy into electricity and a turbine that converts energy into energy and a condenser that cools the working fluid and converts the working fluid into a liquid through heat exchange between the working fluid and hydrogen branched from the pump and supplied to the heater.

According to one embodiment of the present invention, an additional heat exchanger disposed to allow heat exchange between the working fluid passing through the pump and the working fluid passing through the turbine may be further included.

According to the liquefied hydrogen filling station system described above, since hydrogen is introduced into the heater in a primarily heated state, it is possible to achieve an effect of reducing energy required to raise the temperature of hydrogen.

In addition, since hydrogen at room temperature can be pre-cooled close to the target charging temperature before introduction of the cooler, energy required to drive the cooler can be reduced.

In addition, it is possible to achieve the effect of increasing the energy efficiency of the system because heat energy required for heating hydrogen is generated by itself using the boil-off gas.

In addition, it is possible to achieve an effect that the energy efficiency of the system can be increased by self-producing electric energy necessary for driving the heater or the like.

1 is a system diagram for explaining a liquefied hydrogen filling station system according to an embodiment of the present invention.
2 is a flowchart for explaining a method of controlling flow rates branching to flow 3 and flow 10 according to an embodiment of the present invention.
3 is a system diagram for explaining a liquefied hydrogen filling station system according to another embodiment of the present invention.
4 is a diagram embodying the generator structure of the liquefied hydrogen filling station system according to an embodiment of the present invention.
5 is a diagram embodying a generator structure of a liquefied hydrogen filling station system according to another embodiment of the present invention.
6 is a system diagram for explaining a liquefied hydrogen charging system according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Advantages and features of the present disclosure, and methods of achieving them, will become clear with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the technical idea of the present disclosure is not limited to the following embodiments and can be implemented in various different forms, and only the following embodiments complete the technical idea of the present disclosure, and in the technical field to which the present disclosure belongs. It is provided to completely inform those skilled in the art of the scope of the present disclosure, and the technical spirit of the present disclosure is only defined by the scope of the claims.

As described above, the preferred embodiments according to the present invention have been reviewed, and the fact that the present invention can be embodied in other specific forms without departing from the spirit or scope in addition to the above-described embodiments is a matter of ordinary knowledge in the art. It is self-evident to them. Therefore, the embodiments described above are to be regarded as illustrative rather than restrictive, and thus the present invention is not limited to the above description, but may vary within the scope of the appended claims and their equivalents.

In adding reference numerals to components of each drawing, it should be noted that the same components have the same numerals as much as possible even if they are displayed on different drawings. In addition, in describing the present disclosure, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present disclosure, the detailed description will be omitted.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used with meanings commonly understood by those of ordinary skill in the art to which this disclosure belongs. In addition, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless explicitly specifically defined. Terminology used herein is for describing the embodiments and is not intended to limit the present disclosure. In this specification, singular forms also include plural forms unless specifically stated otherwise in a phrase.

In addition, in describing the components of the present disclosure, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, or order of the corresponding component is not limited by the term. When an element is described as being “connected,” “coupled to,” or “connected” to another element, that element is directly connected or connectable to the other element, but there is another element between the elements. It should be understood that elements may be “connected”, “coupled” or “connected”.

As used in this disclosure, "comprises" and/or "comprising" means that a stated component, step, operation, and/or element is one or more other components, steps, operations, and/or elements. Existence or additions are not excluded.

Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

1 is a system diagram for explaining a liquefied hydrogen filling station system according to an embodiment of the present invention.

1 shows only the components related to the embodiment of the present invention, other general-purpose components other than the components shown in FIG. 1 may be further included by those skilled in the art to which the present invention belongs can know

The liquefied hydrogen filling station system 100 according to an embodiment of the present invention includes a storage tank 110, a high pressure pump 120, a catalytic burner 130, a heater 140, a buffer tank 150, a cooler 160, It includes a dispenser 170, a first valve 180 and a second valve 190.

The storage tank 110 stores cryogenic liquefied hydrogen. The storage tank 110 according to an embodiment of the present invention stores hydrogen in a liquid state under a pressure condition of 2 to 3 bar and a temperature condition of -203 ° C to -253 ° C.

The high-pressure pump 120 provides pumping power to transport hydrogen stored in the storage tank 110 . Hydrogen in the flow 2 passing through the high-arm pump 120 is converted into a supercritical fluid state pressurized at about 900 bar and branched into the flow 3 and flow 10.

Hydrogen branched to flow 3 passes through the catalytic combustor 130 and is primarily heated.

The catalytic burner 130 is a device that generates heat by reacting hydrogen and oxygen in the presence of a catalyst such as platinum. The catalytic combustor 130 according to an embodiment of the present invention may use boil-off generated in the storage tank 110 as fuel as gas.

To this end, the liquefied hydrogen filling system 100 according to an embodiment of the present invention is connected to the storage tank 110 and includes a flow 12, which is a flow line for discharging boil-off gas, and a catalytic combustor 130 in the flow line. A flow 13, which is a flow line branching to , may be further included.

In addition, among the boil-off gas generated in the storage tank 110, the boiler-off gas not used in the catalytic combustor 130 is discharged to the outside air or fuel is generated to generate power required to drive the liquid hydrogen charging system 100. It may include a flow line 14 that supplies the cell.

Hydrogen primarily heated in the catalytic combustor 130 flows into the heater 140, is additionally heated, and then stored in the buffer tank 150. Hydrogen according to an embodiment of the present invention is stored in the buffer tank 150 at a temperature of around 25°C.

When the charging operation starts with hydrogen stored in the buffer tank 150 at room temperature, the hydrogen stored in the buffer tank 150 and the hydrogen in the low-temperature/supercritical state branched from the high-pressure pump 120 are mixed at the mixing point. It flows into the cooler 160.

Preferably, the hydrogen temperature after mixing at the mixing point may be -35 °C.

When hydrogen is filled in the external tank through the dispenser 170, the temperature inside the external tank where hydrogen is filled increases due to adiabatic compression. supply Therefore, before supplying hydrogen to the outside through the dispenser 170, the hydrogen must be converted to a pressure condition of 700 bar and a temperature condition of -40 ° C. To cool the hydrogen at room temperature stored in the buffer tank 150 to -40 ° C. It takes a certain amount of time and energy.

Therefore, in order to primarily cool the hydrogen stored in the buffer tank 150, it is mixed with hydrogen in a low-temperature/supercritical state branched from the high-pressure pump 120.

Hydrogen primarily cooled through the above-described process is introduced into the cooler 160, finally converted to a pressure condition of 700 bar and a temperature condition of -40 ° C, and then supplied to the outside through the dispenser 170.

According to the above-described liquefied hydrogen filling station system 100, since hydrogen flows into the heater 140 in a primarily heated state, it is possible to achieve the effect of reducing the energy required to raise the temperature of hydrogen to room temperature. there is.

In addition, it is possible to pre-cool hydrogen at room temperature before introduction into the cooler 160 to a target charging temperature, thereby achieving an effect of reducing energy required to drive the cooler 160 .

2 is a flowchart for explaining a method of controlling flow rates branching to flow 3 and flow 10 according to an embodiment of the present invention.

The liquefied hydrogen filling system 100 according to an embodiment of the present invention is a sensing unit (not shown) for sensing the temperature of hydrogen passing through the mixing point, branched from the rear end of the high-pressure pump 120 and the flow rate flowing into the mixing point A control unit (not shown) may further be included to control the first valve 180 for controlling and the second valve 190 for controlling the flow rate branched from the rear end of the high pressure pump 120 and flowing into the catalytic combustor 130. .

The temperature of the hydrogen stored in the buffer tank 150 and the hydrogen passing through the flow line may change according to the temperature of the outside air. Accordingly, the controller according to an embodiment of the present invention controls the open/closed state of the first valve 180 and the second valve 190 so that the temperature of the hydrogen passing through the flow 7 before being introduced into the cooler 160 is cooled to the target temperature. can control.

When the charging operation starts, the control unit receives the temperature information in the flow 7 after the mixing point (S210). The hydrogen temperature in flow 7 is compared with the target temperature (S220), and if the hydrogen temperature in flow 7 matches the target temperature, charging proceeds as it is (S260). Preferably, the target temperature according to an embodiment of the present invention may be -35 °C.

If the hydrogen temperature of flow 7 does not match the target temperature, it is determined whether the hydrogen temperature of flow 7 is higher than the target temperature (S230). When the hydrogen temperature of flow 7 is higher than the target temperature, it takes a predetermined amount of time to lower it to the charging temperature of −40° C., and additional energy is consumed to drive the cooler 160 .

Accordingly, the control unit according to an embodiment of the present invention opens the first valve 180 to increase the hydrogen flow rate branched from the high pressure pump 120 to the mixing point, and branches from the high pressure pump 120 to the catalytic combustor 130. A control signal for closing the second valve 190 is generated so that the hydrogen flow rate decreases. According to the control operation, when the temperature of the hydrogen passing through the mixing point is lowered to reach the target temperature (S220), the charging operation proceeds.

On the other hand, if the hydrogen temperature of flow 7 is lower than the target temperature, the charging temperature may be lower than -40 ° C. In this case, the control unit closes the first valve 180 and opens the second valve 190. generate a signal

On the other hand, the liquefied hydrogen charging system 100 according to an embodiment of the present invention may include other configurations for raising cryogenic liquefied hydrogen to a target temperature in a short time and maximizing energy efficiency.

3 is a system diagram for explaining a liquefied hydrogen filling station system according to another embodiment of the present invention.

The liquefied hydrogen charging system 100 according to an embodiment of the present invention further includes a generator 200 disposed between the high-pressure pump 120 and the heater 140.

The generator 200 according to an embodiment of the present invention recovers and utilizes cold heat energy to generate electric energy and supplies it to the heater 140 to heat hydrogen to room temperature before storing it in the buffer tank 150. there is.

In addition, in the generator 200, heat exchange is performed between the low-temperature hydrogen and the working fluid circulating inside the generator 200, so that the temperature of hydrogen can be increased after passing through the generator 200.

Hereinafter, the internal structure and power generation cycle of the generator 200 according to an embodiment of the present invention will be described in more detail.

4 is a diagram embodying the generator structure of the liquefied hydrogen filling station system according to an embodiment of the present invention.

Generator 200 according to an embodiment of the present invention includes a pump 201, an evaporator 202, a turbine 203 and a condenser 204. The generator 200 according to an embodiment of the present invention may circulate a working fluid to rotate the turbine 203 and convert axial power of the turbine 203 into electrical energy.

Preferably, an organic compound such as a Freon-based refrigerant or a propane-based hydrocarbon may be used as the working fluid of the generator 200 according to an embodiment of the present invention.

The pump 201 pressurizes the low-temperature and low-pressure working fluid and converts it into a low-temperature and high-pressure state. The working fluid pressurized by the pump 201 flows into the evaporator 202 . The evaporator 202 serves to receive thermal energy from the outside and supply it to the working fluid, and may have a typical plate-type heat exchanger form.

In the evaporator 202, the working fluid changes from a low-temperature/high-pressure state to a high-temperature/high-pressure gaseous state through heat exchange. The working fluid, which has been changed to a high-temperature and high-pressure gaseous state, flows into the turbine 203 and rapidly rotates the rotor of the turbine 203 to pass through. At this time, the kinetic energy of the turbine 203 is converted into electrical energy.

The turbine 203 according to one embodiment of the present invention may be implemented in various forms such as a screw type, a scroll type, a vane type, a piston type, etc., but is not limited thereto.

The working fluid passing through the turbine 203 is converted into a high-temperature and low-pressure state and introduced into the condenser 204 .

In the condenser 204, the working fluid converted to a high-temperature and low-pressure state is changed to a low-temperature and low-pressure liquid through heat exchange with low-temperature hydrogen flowing through flow 4. In addition, the hydrogen of flow 4 absorbs the heat of the working fluid and the temperature rises.

The working fluid changed to a low-temperature and low-pressure liquid is introduced into the pump 201 again, and the above-described cycle is repeated.

According to the generator 200 described above, it is possible to achieve an effect of increasing energy efficiency by generating electric energy even from a low-temperature heat source and supplying it to the heater 140 .

In addition, since the temperature of hydrogen in flow 4 rises through heat exchange with the generator 200, the effect of converting low-temperature hydrogen to room temperature and reducing the time and energy required for temperature rise before storing in the buffer tank 150 can be achieved

5 is a diagram embodying a generator structure of a liquefied hydrogen filling station system according to another embodiment of the present invention.

The generator 200 according to another embodiment of the present invention may further include an additional heat exchanger 205.

In one embodiment of the present invention, the additional heat exchanger 205 is arranged to exchange heat between the low-temperature and high-pressure working fluid that has passed through the pump 201 and the high-temperature and low-pressure working fluid that has passed through the turbine 203.

Since the temperature of the working fluid before flowing into the evaporator 202 is higher and the temperature of the working fluid before flowing into the condenser 224 is lowered by the additional heat exchanger described above, the effect of increasing the thermal efficiency can be achieved. can

6 is a system diagram for explaining a liquefied hydrogen charging system according to another embodiment of the present invention.

The liquefied hydrogen charging system 100 according to an embodiment of the present invention may include a generator 200 and a catalytic burner 130 disposed in a supply line branching from the high pressure pump 120 to the heater 140. .

As described above, the generator 200 generates electric energy by the working fluid circulating therein, and raises the temperature of the hydrogen through heat exchange between the hydrogen and the working fluid. At this time, the electric energy generated by the generator 200 is used to drive the heater 140 to raise the temperature of hydrogen to room temperature.

The catalytic combustor 130 generates thermal energy using the boil-off gas generated in the storage tank 110 and uses it to raise the temperature of hydrogen.

Therefore, it is possible to reduce the energy required to raise the temperature of the hydrogen to room temperature before storing the hydrogen in the buffer tank 150, thereby increasing the energy efficiency of the liquid hydrogen charging system 100.

In the above, even though all the components constituting the embodiments of the present disclosure have been described as being combined or operated as one, the technical idea of the present disclosure is not necessarily limited to these embodiments. That is, within the scope of the purpose of the present disclosure, all of the components may be selectively combined with one or more to operate.

Although the embodiments of the present disclosure have been described with reference to the accompanying drawings, those skilled in the art may implement the present disclosure in other specific forms without changing the technical spirit or essential features. can understand that there is Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. The protection scope of the present disclosure should be construed by the following claims, and all technical ideas within the equivalent range should be construed as being included in the scope of rights of the technical ideas defined by the present disclosure.

Claims (10)

a storage tank for storing liquid hydrogen;
a high-pressure pump providing a pumping force for transporting the hydrogen stored in the storage tank;
a catalytic combustor that heats the hydrogen diverged from the output terminal of the high-pressure pump by generating heat using boil-off gas generated in the storage tank as a fuel source;
a heater for additionally heating the hydrogen primarily heated in the catalytic combustor;
a buffer tank for temporarily storing the hydrogen heated by the heater;
a cooler for mixing hydrogen stored in the buffer tank with hydrogen branched from the high-pressure pump at a mixing point and cooling the hydrogen introduced at the mixing point; and
A liquid hydrogen filling system including a dispenser for injecting cooled hydrogen into an external hydrogen tank. According to claim 1,
a sensing unit for sensing the temperature of the hydrogen mixed at the mixing point;
a first valve branched from the rear end of the high-pressure pump and controlling a flow rate flowing into the mixing point;
a second valve branched from the rear end of the high-pressure pump and controlling a flow rate flowing into the catalytic combustor; and
The liquefied hydrogen charging system further comprises a control unit for controlling the opening and closing of the first valve and the second valve. According to claim 2,
The control unit,
When the temperature of the hydrogen mixed at the mixing point is higher than the target temperature, a control signal for opening the first valve and closing the second valve is generated. According to claim 2,
The control unit,
When the temperature of the hydrogen mixed at the mixing point is lower than the target temperature, generating a control signal for closing the first valve and opening the second valve. According to claim 1,
The liquefied hydrogen charging system further comprises a generator disposed between the high-pressure pump and the catalytic combustor to generate electric energy required to drive the heater using cold heat energy. According to claim 5,
the generator,
a pump that pressurizes the working fluid;
An evaporator that heats the working fluid to raise its temperature and vaporizes it;
A turbine converting kinetic energy into electrical energy by rotating a rotor when the working fluid passes therethrough; and
and a condenser cooling the working fluid and converting the working fluid into a liquid through heat exchange between the working fluid and hydrogen branched from the pump and flowing into the catalytic combustor. According to claim 6,
The liquefied hydrogen charging system further comprises an additional heat exchanger arranged to perform heat exchange between the working fluid that has passed through the pump and the working fluid that has passed through the turbine. a storage tank for storing liquid hydrogen;
a high-pressure pump providing a pumping force for transporting the hydrogen stored in the storage tank;
a generator disposed between the high-pressure pump and the heater to generate electric energy required to drive the heater using cold heat energy;
a heater for additionally heating the hydrogen primarily heated through heat exchange in the generator;
a buffer tank for temporarily storing the hydrogen heated by the heater;
a cooler for mixing hydrogen stored in the buffer tank with hydrogen branched from the high-pressure pump at a mixing point and cooling the hydrogen introduced at the mixing point; and
A liquid hydrogen filling system including a dispenser for injecting cooled hydrogen into an external hydrogen tank. According to claim 8,
the generator,
a pump that pressurizes the working fluid;
An evaporator that heats the working fluid to raise its temperature and vaporizes it;
A turbine converting kinetic energy into electrical energy by rotating a rotor when the working fluid passes therethrough; and
and a condenser cooling the working fluid and converting the working fluid into a liquid through heat exchange between the working fluid and hydrogen branched from the pump and supplied to the heater. According to claim 9,
The liquefied hydrogen charging system further comprises an additional heat exchanger arranged to perform heat exchange between the working fluid that has passed through the pump and the working fluid that has passed through the turbine.

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