JP2021138557A - Hydrogen generation device - Google Patents

Abstract

To provide a hydrogen generation device which suppresses energy for vaporization of water into steam for humidifying a raw material and energy for removal of water in exhaust gas, suppressing energy for collecting carbon dioxide from the exhaust gas.SOLUTION: A hydrogen generation device 41 in the present disclosure comprises: a reformer 1 which generates a hydrogen-containing gas from city gas and water; a heater 2 which combusts fuel to heat the reformer 1; an exhaust gas flow path 10 through which to feed exhaust gas discharged from the heater 2 to a first adsorber 21 or a second adsorber 22 mounted with a carbon dioxide adsorbent; a raw material flow path 8 through which to feed a raw material to the reformer 1; and a water permeation device 12 in which the exhaust gas flow path 10 and the raw material flow path 8 are divided by a water permeable membrane. Thereby, water in the exhaust gas moves into the city gas via the water permeable membrane of the water permeation device 12, enabling removal of the water in the exhaust gas and humidification of the city gas.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a hydrogen generator.

Patent Document 1 discloses a method for separating carbon dioxide from exhaust gas.

In the method of separating carbon dioxide from exhaust gas, the exhaust gas is supplied to a dehumidifying tower equipped with a water adsorbent to remove water, and then the dehumidified exhaust gas is supplied to the carbon dioxide adsorption tower to adsorb and separate carbon dioxide. Then, the residual gas from which carbon dioxide has been removed is discharged.

Further, the residual gas discharged from the carbon dioxide adsorption tower is depressurized by a vacuum pump while being supplied to the dehumidification tower, and the water is regenerated by desorbing water from the water adsorbent on which the water is adsorbed.

Japanese Unexamined Patent Publication No. 7-80246

In the present disclosure, the energy for evaporating water to make water vapor for humidifying the raw material and the energy for removing the water contained in the exhaust gas are suppressed, and the energy for recovering carbon dioxide from the exhaust gas is suppressed. A hydrogen generator is provided.

In the hydrogen generator in the present disclosure, the exhaust gas flow path for supplying the exhaust gas discharged from the reformer to the carbon dioxide adsorber and the raw material flow path for supplying the raw material to the reformer are water permeable membranes. It is equipped with a water permeator partitioned by.

In the hydrogen generator of the present disclosure, the water contained in the exhaust gas is transferred to the raw material having less water than the exhaust gas through the water permeable film of the water permeator, so that the water contained in the exhaust gas can be removed and the raw material can be removed. Can be humidified.

Therefore, it is possible to suppress the energy for evaporating water to make water vapor for humidifying the raw material and the energy for removing the water contained in the exhaust gas.

The block diagram which shows the structure of the hydrogen generation apparatus in Embodiment 1. A flowchart showing a start-up operation of the hydrogen generator according to the first embodiment. A flowchart showing a carbon dioxide adsorption operation operation of the hydrogen generator according to the first embodiment. The block diagram which shows the structure of the hydrogen generation apparatus in Embodiment 2. The block diagram which shows the structure of the hydrogen generation apparatus in Embodiment 3.

(Findings, etc. that form the basis of this disclosure)
At the time when the inventors came up with the present disclosure, water that adsorbs and removes water before the adsorbent in order to adsorb and separate carbon dioxide from the exhaust gas discharged from the hydrogen generator by the adsorbent. The configuration in which the adsorbent was installed was common.

Since water is strongly adsorbed on the water adsorbent, it is necessary to reduce the partial pressure of water by reducing the pressure with a vacuum pump when the water adsorbent is desorbed and regenerated.

As described above, in order to remove the water contained in the exhaust gas, a large amount of energy such as electric power for operating the vacuum pump was required.

Further, in order to carry out steam reforming in a hydrogen generator, it was common to evaporate water using an evaporator to humidify the raw material.

Under such circumstances, the inventors have discovered that there is a problem of suppressing the energy for evaporating water to make water vapor to humidify the raw material and the energy for removing the water contained in the exhaust gas. However, in order to solve the problem, the subject matter of the present disclosure has been constructed.

Therefore, the present disclosure suppresses the energy for evaporating water to make water vapor for humidifying the raw material and the energy for removing the water contained in the exhaust gas, and the energy for recovering carbon dioxide from the exhaust gas. Provided is a hydrogen generating apparatus in which the amount of carbon dioxide is suppressed.

Hereinafter, embodiments will be described in detail with reference to the drawings. However, more detailed explanation than necessary may be omitted. For example, detailed explanations of already well-known matters or duplicate explanations for substantially the same configuration may be omitted.

It should be noted that the accompanying drawings and the following description are provided for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

(Embodiment 1)
Hereinafter, the first embodiment will be described with reference to FIGS. 1 to 3.

[1-1. composition]
As shown in FIG. 1, the hydrogen generator 41 includes a reformer 1, a heater 2, a raw material supply device 3, a water supply device 4, a fuel supply device 5, an air supply device 6, and an exhaust valve 7. , The raw material flow path 8, the hydrogen-containing gas supply flow path 9, the exhaust gas flow path 10, the fuel flow path 11, the water permeator 12, the temperature detector 13, the first adsorber 21, and the second. It includes an adsorber 22, a first adsorber upstream valve 23, a first adsorber downstream valve 24, a second adsorber upstream valve 25, a second adsorber downstream valve 26, and a controller 31.

The hydrogen-containing gas supply flow path 9 is connected to the fuel cell 51, which is a hydrogen utilization device.

The reformer 1 produces a hydrogen-containing gas by a reforming reaction using a raw material and steam. In this embodiment, city gas containing methane as a main component was used as a raw material. In the present embodiment, steam reforming in which city gas and steam are reacted is used as the reforming reaction. A reforming catalyst (not shown) is mounted inside the reformer 1.

The heater 2 is a combustor that heats the reformer 1.

The raw material supply device 3 is a gas pump that supplies city gas to the reformer 1 through the raw material flow path 8.

The water supply device 4 is a water pump that supplies water to the reformer 1.

The fuel supply device 5 is a gas pump that supplies fuel to the heater 2, and is connected to the fuel flow path 11. In this embodiment, city gas containing methane as a main component was used as the fuel.

The air supply device 6 is a fan that supplies combustion air to the heater 2.

The hydrogen-containing gas supply flow path 9 is a flow path that guides the hydrogen-containing gas discharged from the reformer 1 to the fuel cell 51.

The exhaust gas flow path 10 is a flow path for exhausting the combustion exhaust gas discharged from the heater 2, and an exhaust valve 7 is installed in the middle of the exhaust gas flow path 10.

The fuel flow path 11 is a flow path for supplying fuel to the heater 2.

The water permeator 12 has the raw material flow path 8 and the exhaust gas flow path 10 so that the city gas flowing through the raw material flow path 8 and the exhaust gas flowing through the exhaust gas flow path 10 are adjacent to each other with the water permeation film in between. It is provided in the middle of the structure so that water moves from the exhaust gas to the city gas due to the difference in water vapor partial pressure between the exhaust gas and the city gas. In the present embodiment, a water-permeable polyimide-based membrane is used as the water-permeable membrane.

The temperature detector 13 is a thermocouple that measures the temperature Tr of the reforming catalyst.

The first adsorber 21 and the second adsorber 22 are adsorbers that adsorb and remove carbon dioxide contained in the exhaust gas discharged from the heater 2 by an adsorbent (not shown) mounted inside. In this embodiment, NaX-type zeolite, which is generally used for adsorbing carbon dioxide, is used as an adsorbent.

The first adsorber upstream valve 23 and the first adsorber downstream valve 24 are solenoid valves installed upstream and downstream of the first adsorber 21 with respect to the flow direction of the exhaust gas flow path 10, respectively.

The second adsorber upstream valve 25 and the second adsorber downstream valve 26 are solenoid valves installed upstream and downstream of the second adsorber 22 with respect to the flow direction of the exhaust gas flow path 10, respectively.

The controller 31 controls the operation of the hydrogen generating device 41. The controller 31 includes a signal input / output unit (not shown), an arithmetic processing unit (not shown), and a storage unit (not shown) for storing a control program.

The fuel cell 51 is a device that generates electricity from hydrogen in a hydrogen-containing gas and air.

[1-2. motion]
The operation of the hydrogen generating apparatus 41 configured as described above will be described below.

The following operations are performed by the controller 31 controlling the hydrogen generating device 41.

FIG. 2 is a flowchart showing the activation operation of the hydrogen generator according to the first embodiment.

Before the hydrogen generator 41 is started, the hydrogen generator 41 is stopped, and the exhaust valve 7, the first adsorber upstream valve 23, the first adsorber downstream valve 24, the second adsorber upstream valve 25, and the second Adsorber downstream valve 2
6 is a closed state, respectively.

First, the exhaust valve 7 is opened in order to start the hydrogen generator 41 (S101).

Next, the fuel supply device 5 and the air supply device 6 are made to supply the heater 2 and the heater 2 is made to ignite, and the mixture of the fuel and the air for combustion is burned by the heater 2. The heating of the reformer 1 is started (S102).

At this time, the supply amount (flow rate) of city gas from the fuel supply device 5 to the heater 2 is 1 L / min. The amount of air supplied (flow rate) from the air supply device 6 to the heater 2 is 20 L / min.

Next, by operating the raw material supply device 3, the supply of city gas to the reformer 1 is started (S103). At this time, the supply amount (flow rate) of city gas from the raw material supply device 3 to the reformer 1 is 4 L / min.

Next, it is confirmed whether the reforming temperature Tr of the reformer 1 detected by the temperature detector 13 has risen to 100 ° C. or higher (S104). As a result of confirmation, if the reforming temperature Tr has not risen to 100 ° C. or higher, S104 is repeated until the reforming temperature Tr rises to 100 ° C. or higher. Here, the reforming temperature of 100 ° C. is a temperature at which water does not condense in the reformer 1 even if water is supplied to the reformer 1.

In S104, when the reforming temperature Tr of the reformer 1 rises to 100 ° C. or higher, the water supply device 4 is operated to start supplying water to the reformer 1 (S105). At this time, the amount of water supplied (flow rate) from the water supply device 4 to the reformer 1 is 11 cc / min.
The water supply amount of 11 cc / min is the molar ratio of the reforming steam (S) and the carbon (C) contained in the city gas when the city gas is supplied to the reformer 1 at a supply amount of 4 L / min. This is a value at which the S / C ratio is 3.

Next, it is confirmed whether the reforming temperature Tr of the reformer 1 detected by the temperature detector 13 has risen to 600 ° C. or higher (S106). As a result of confirmation, if the reforming temperature Tr has not risen to 600 ° C. or higher, S106 is repeated until the reforming temperature Tr rises to 600 ° C. or higher.

Here, the reforming temperature of 600 ° C. is a temperature obtained experimentally in advance, and the reformer 1 can generate hydrogen-containing gas from city gas at a predetermined conversion rate, which is suitable for supplying to the fuel cell 51. This is the temperature at which the amount of hydrogen can be obtained.

In S106, when the reforming temperature Tr of the reformer 1 rises to 600 ° C. or higher, the exhaust valve 7 is closed and the first adsorber upstream valve 23 and the first adsorber downstream valve 24 are opened to release the exhaust gas. It is supplied to the first adsorber 21 (S107).

Next, the fuel cell 51 starts power generation (S108), ends the start of the hydrogen generator 41, and shifts to the carbon dioxide adsorption operation operation. The power generation output of the fuel cell 51 at this time is 1 kW. Here, the power generation output of 1 kW is a power generation output suitable for generating the fuel cell 51 from the amount of hydrogen generated when the city gas is supplied to the fuel cell 51 with a supply amount (flow rate) of 4 L / min.

The city gas supplied to the reformer 1 by the raw material supply device 3 passes through the water permeator 12 arranged in the middle of the raw material flow path 8. Further, the exhaust gas discharged from the heater 2 passes through the water permeator 12 arranged in the middle of the exhaust gas flow path 10.

The water permeator 12 has a water permeation film that separates the exhaust gas flow path 10 and the raw material flow path 8, and the exhaust gas contains water, but the city gas contains almost no water, so that it is included in the exhaust gas. Moisture is transferred to the city gas through the water permeable membrane.

FIG. 3 is a flowchart showing a carbon dioxide adsorption operation operation of the hydrogen generating apparatus 41 according to the first embodiment.

First, it is confirmed whether the elapsed time T1 after opening the first adsorber upstream valve 23 is 4 hours or more (S201). As a result of the confirmation, if the elapsed time T1 after opening the first suction device upstream valve 23 is not 4 hours or more, S201 is repeated until the elapsed time T1 becomes 4 hours or more.

Here, the predetermined time of 4 hours is the time during which carbon dioxide in the exhaust gas can be removed by the first adsorber 21 of the present embodiment, and when that time is exceeded, the first adsorber 21 emits carbon dioxide. It is a time when carbon dioxide cannot be completely adsorbed and carbon dioxide starts to be discharged to the downstream side of the first adsorber 21.

In S201, when the elapsed time T1 from opening the first adsorber upstream valve 23 becomes 4 hours or more, the first adsorber upstream valve 23 and the first adsorber downstream valve 24 are closed, respectively, and the second adsorber upstream. By opening the valve 25 and the second adsorber downstream valve 26, respectively, the supply destination of the exhaust gas is switched from the first adsorber 21 to the second adsorber 22 (S202).

Next, the first adsorber 21 is replaced with a recycled product (S203). Here, the recycled product is a product in which carbon dioxide is desorbed from the adsorbent mounted on the adsorber by removing the adsorber that has adsorbed carbon dioxide and connecting a pump to reduce the pressure inside the adsorber. , The same as the one regenerated by adsorbing carbon dioxide on the first adsorber 21 and the second adsorber 22.

The desorbed carbon dioxide can be recovered and stored, or used as carbon dioxide gas in industry, agriculture, food, and the like.

Next, it is confirmed whether the elapsed time T1 after opening the second adsorber upstream valve 25 is 4 hours or more (S204). As a result of confirmation, if the elapsed time T1 after opening the second adsorber upstream valve 25 is not 4 hours or more, S204 is repeated until the elapsed time T1 becomes 4 hours or more.

In S204, when the elapsed time T1 from opening the second adsorber upstream valve 25 becomes 4 hours or more, the second adsorber upstream valve 25 and the second adsorber downstream valve 26 are closed, respectively, and the first adsorber upstream. By opening the valve 23 and the first adsorber downstream valve 24, respectively, the supply destination of the exhaust gas is switched from the second adsorber 22 to the first adsorber 21 (S205).

Next, the second adsorber 22 is replaced with a recycled product (S206), the process returns to S201, and the same operation is repeated.

[1-3. Effect, etc.]
As described above, the hydrogen generator 41 of the present embodiment is composed of the reformer 1 that generates hydrogen-containing gas from city gas and water, the heater 2 that heats the reformer 1, and the heater 2. The exhaust gas flow path 10 that supplies the discharged exhaust gas to the first adsorber 21 or the second adsorber 22, the raw material flow path 8 that supplies the raw material to the reformer 1, and the exhaust gas flow path 10 and the raw material flow path 8. A water permeator 12 and a water permeator 12 are provided.

As a result, the water contained in the exhaust gas moves to the city gas via the water permeable film of the water permeator 12, so that the water contained in the exhaust gas can be removed and the city gas can be humidified.

Therefore, it is possible to suppress the energy for evaporating water to make water vapor for humidifying the raw material and the energy for removing the water contained in the exhaust gas.

(Embodiment 2)
Hereinafter, the second embodiment will be described with reference to FIG.

[2-1. composition]
As shown in FIG. 4, the hydrogen generating device 42 according to the second embodiment sets the position of the raw material supply device 3 as the raw material on the upstream side of the water permeator 12 in the configuration of the hydrogen generating device 41 of the first embodiment. The flow path 8 is changed to the raw material flow path 8 on the downstream side of the water permeator 12, and the connection destination of the hydrogen-containing gas supply flow path 9 is changed from the fuel cell 51 to the hydrogen tank 52.

[2-2. motion]
Since the basic operation of the hydrogen generation device 42 configured as described above is the same as that of the first embodiment, duplicate description will be omitted.

Since the raw material supply device 3 is composed of a gas pump that conveys the city gas to the reformer 1, the pressure of the city gas in the raw material flow path 8 on the upstream side of the raw material supply device 3 is the raw material supply device 3. It becomes lower than the pressure of the city gas in the raw material flow path 8 on the downstream side.

In the present embodiment, since the raw material supply device 3 is arranged in the raw material flow path 8 on the downstream side of the water permeator 12, the raw material supply device 3 is arranged in the raw material flow path 8 on the upstream side of the water permeator 12. The water vapor partial pressure on the city gas side of the water permeable film is lower than that of the hydrogen generating device 41 of the first embodiment.

Therefore, the hydrogen generating device 42 of the present embodiment has a larger amount of water permeating from the exhaust gas side to the city gas side through the water permeation film in the water permeator 12 than the hydrogen generating device 41 of the first embodiment. Therefore, the dehumidifying effect of the exhaust gas is higher than that of the hydrogen generating device 41 of the first embodiment, and at the same time, the humidifying effect of the city gas is higher.

[2-3. Effect, etc.]
As described above, the hydrogen generating device 42 of the present embodiment is the position of the raw material supply device 3 including the gas pump for transporting the city gas to the reformer 1 in the configuration of the hydrogen generating device 41 of the first embodiment. Was changed from the raw material flow path 8 on the upstream side of the water permeator 12 to the raw material flow path 8 on the downstream side of the water permeator 12, so that the water permeator 12 on the city gas side of the water permeation film The pressure can be made lower than the pressure on the exhaust gas side of the water permeable film.

Further, by arranging the raw material supply device 3 including the gas pump for transporting the city gas to the reformer 1 in the raw material flow path 8 on the downstream side of the water permeator 12, the hydrogen generation device according to the first embodiment. The partial pressure of water vapor on the city gas side of the water permeable film is lower than that of 41, and the permeation of water from the exhaust gas side to the city gas side is promoted.

As a result, the city gas supplied to the reformer 1 is humidified, and the amount of water in the exhaust gas supplied to the first adsorber 21 or the second adsorber 22 equipped with the adsorbent that adsorbs carbon dioxide is reduced. It is possible to suppress the deterioration of performance due to the moisture content of the adsorbent.

Therefore, the hydrogen generator 42 suppresses the energy for evaporating water to become water vapor for humidifying the city gas and the energy for removing water in the exhaust gas, and further deteriorates the performance due to the water content of the adsorbent. Can be suppressed.

(Embodiment 3)
Hereinafter, the third embodiment will be described with reference to FIG.

[3-1. composition]
As shown in FIG. 5, the hydrogen generation device 43 according to the third embodiment is used as a city gas in the raw material flow path 8 on the upstream side of the raw material supply device 3 in the configuration of the hydrogen generation device 41 of the first embodiment. It corresponds to the addition of a desulfurizer 14 for removing the contained sulfur component.

[3-2. motion]
Since the basic operation of the hydrogen generation device 43 configured as described above is the same as that of the first embodiment, duplicate description will be omitted.

[3-3. Effect, etc.]
As described above, the hydrogen generator 43 of the present embodiment is provided with the desulfurizer 14 for removing the sulfur component contained in the city gas in the raw material flow path 8 on the upstream side of the water permeator 12. The sulfur component contained in the city gas permeates the water permeable film and is mixed into the exhaust gas, and the sulfur component is supplied to the adsorbent, so that deterioration of the adsorbent can be suppressed.

Therefore, the hydrogen generator 43 further supplies the sulfur component to the adsorbent while suppressing the energy for evaporating water to make water vapor for humidifying the city gas and the energy for removing water in the exhaust gas. As a result, deterioration of the adsorbent can be suppressed.

(Other embodiments)
As described above, Embodiments 1 to 3 have been described as examples of the techniques disclosed in the present application. However, the technique in the present disclosure is not limited to this, and can be applied to embodiments in which changes, replacements, additions, omissions, etc. have been made. It is also possible to combine the components described in the first to third embodiments to form a new embodiment.

Therefore, other embodiments will be illustrated below.

In the first to third embodiments, a polyimide-based membrane is used as the water permeable membrane of the water permeator 12, but the water permeable membrane is not limited to this, and the water permeable membrane moves the water in the exhaust gas to the city gas. Any gas other than water may be used as long as it does not easily permeate, and a fluorine-based membrane used in a fuel cell or the like, an inorganic membrane such as a zeolite membrane or a silica membrane, or the like may be used.

Further, in the first to third embodiments, the amount of water transferred from the exhaust gas to the city gas by the water permeator 12 is 3 cc / min, and a total of 11 cc / min of water is supplied to the reformer 1. However, since the area of the water permeable membrane and the difference in the partial pressure between the exhaust gas and the city gas change the amount of water that moves from the exhaust gas to the city gas, the water permeator 12 was designed. Therefore, the amount of water supplied from the water supply device 4 may be increased or decreased so as to have a total of 11 cc / min.

Since the above-described embodiment is for exemplifying the technique in the present disclosure, various changes, replacements, additions, omissions, etc. can be made within the scope of claims or the equivalent scope thereof.

The present disclosure is applicable to a hydrogen generator in which energy for recovering carbon dioxide from exhaust gas is suppressed. Specifically, the present disclosure is applicable to hydrogen production equipment using hydrocarbons as fuel, fuel cell power generation systems, generators, and the like.

1 Reformer 2 Heater 3 Raw material supply device 4 Water supply device 5 Fuel supply device 6 Air supply device 7 Exhaust valve 8 Raw material flow path 9 Hydrogen-containing gas supply flow path 10 Exhaust gas flow path 11 Fuel flow path 12 Water permeator 13 Temperature detector 14 Desulfurizer 21 1st adsorber 22 2nd adsorber 23 1st adsorber upstream valve 24 1st adsorber downstream valve 25 2nd adsorber upstream valve 26 2nd adsorber downstream valve 31 Controller 41, 42 , 43 Hydrogen generator 51 Fuel cell 52 Hydrogen tank

Claims (5)

A reformer that produces hydrogen-containing gas from raw materials and water,
An exhaust gas flow path for supplying the exhaust gas discharged from the reformer to the carbon dioxide adsorber,
A raw material flow path for supplying the raw material to the reformer, and
A water permeator in which the exhaust gas flow path and the raw material flow path are separated by a water permeation membrane,
A hydrogen generator equipped with. The hydrogen generating apparatus according to claim 1, wherein the exhaust gas is combustion exhaust gas discharged from a heater that burns fuel and heats the reformer. The hydrogen generation according to claim 1 or 2, wherein in the water permeator, the pressure on the raw material gas side of the water permeation membrane is lower than the pressure on the exhaust gas side of the water permeation membrane. Device. The hydrogen generating apparatus according to claim 3, further comprising a raw material supply device for transporting the raw material to the reformer in the raw material flow path on the downstream side of the water permeator. The hydrogen generating apparatus according to any one of claims 1 to 4, further comprising a desulfurizer for removing a sulfur component contained in the raw material in the raw material flow path on the upstream side of the water permeator.

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