JP2019172551A - Hydrogen production equipment - Google Patents

Abstract

To provide a hydrogen production equipment capable of reducing heat quantity released with combustion exhaust gas.SOLUTION: The hydrogen production equipment comprises: a reforming part A which includes a reforming reaction part 2 reforming a raw material gas G into a hydrogen-rich reformed gas K by a steam reforming process and a combustion part 3 heating the reforming reaction part 2; a pressure swing absorption part B which absorbs, by an absorbent, components to be absorbed other than the hydrogen component included in the reformed gas K from the reforming reaction part A to generate a production gas H; an off-gas supply channel 4 which supplies an off-gas exhausted from the pressure swing absorption part B to the combustion part 3; and a control part M which performs feedforward control for supplying a target combustion air amount for combustion of combustion components in the off-gas to the combustion part 3 on the basis of an off-gas supply amount detected by an off-gas supply amount detection part 36 and on a hydrogen concentration and a methane concentration detected by a concentration detection part N.SELECTED DRAWING: Figure 1

Description

A reforming section having a reforming reaction section for reforming a raw material gas, which is a hydrocarbon-based gas, to a reformed gas having a large amount of hydrogen components by steam reforming; and a reforming section having a combustion section for heating the reforming reaction section; A pressure fluctuation adsorption part having an adsorption tower for producing a product gas by adsorbing an adsorption target component other than a hydrogen component contained in the reformed gas from a mass part to an adsorbent, and discharged from the pressure fluctuation adsorption part An off-gas supply path for supplying off-gas to the combustion section;
A control unit for controlling the operation of the combustion unit controls an off gas supply amount for supplying the off gas to the combustion unit and heats combustion air to the combustion unit so as to heat the reforming reaction unit to a reforming reaction temperature. The present invention relates to a hydrogen production apparatus configured to control the amount of combustion air supplied to the fuel.

  Such a hydrogen production apparatus reforms a raw material gas, which is a hydrocarbon gas such as natural gas or naphtha, into a reformed gas having a large amount of hydrogen components by a steam reforming process using a reforming unit, A product gas having a high hydrogen concentration is produced by adsorbing an adsorbing target component on an adsorbent from a reformed gas containing an adsorbing target component other than the component and the hydrogen component.

  The off-gas discharged from the pressure fluctuation adsorbing part contains hydrogen, methane, and carbon monoxide as combustible components. Therefore, in order to heat the reforming reaction part to the temperature for the reforming reaction, An off-gas discharged is supplied to a combustion section that heats a reforming reaction section of the reforming section and burned (see, for example, Patent Document 1).

JP 2002-53307 A

The off-gas contains hydrogen, methane, and carbon monoxide as combustible components, but the concentration of hydrogen and the concentration of methane contained in the off-gas are variously changed depending on the operating conditions.
In general, the reformed gas is supplied to the CO converter, the carbon monoxide contained in the reformed gas is converted to carbon dioxide, and the reformed reformed gas is supplied to the pressure fluctuation adsorption unit. Therefore, the amount of carbon monoxide contained in the off-gas is very small and does not vary greatly.

  Conventionally, as a state of the combustible component contained in the off-gas, for example, a state where the most amount of combustion air is required, such as a state where the concentration of methane is high, the combustible component in the assumed state is burned. Since the large amount of combustion air required to do this is supplied to the burner that burns off gas, the large amount of combustion air is supplied even when a large amount of combustion air is not required. There was a thing.

  That is, the amount of combustion air increases as the off-gas supply amount supplied to the combustion section increases, but the amount of combustion air supplied per unit amount of off-gas is reduced by the combustible component contained in the off-gas. As a state, assuming a state where the most amount of combustion air is required, a larger amount of combustion air required to burn the combustible component in the assumed state is set.

  For this reason, even when a large amount of combustion air is not required as the amount of combustion air for burning the combustible components contained in the off-gas, more combustion air may be supplied than necessary. In such a case, there is a possibility that a large amount of heat is discharged in vain with a large amount of combustion exhaust gas.

  This invention is made | formed in view of the said actual condition, The objective is to provide the hydrogen production apparatus which can reduce the calorie | heat amount discharge | released with combustion exhaust gas.

The hydrogen production apparatus of the present invention includes a reforming reaction section that reforms a raw material gas that is a hydrocarbon-based gas into a reformed gas having a large amount of hydrogen components by steam reforming, and a combustion section that heats the reforming reaction section. A reforming unit, and a pressure fluctuation adsorption unit including an adsorption tower that adsorbs an adsorption target component other than a hydrogen component contained in the reformed gas from the reforming unit to an adsorbent, An off-gas supply path for supplying off-gas discharged from the pressure fluctuation adsorption unit to the combustion unit is provided,
A control unit for controlling the operation of the combustion unit controls an off gas supply amount for supplying the off gas to the combustion unit and heats combustion air to the combustion unit so as to heat the reforming reaction unit to a reforming reaction temperature. Is configured to control the amount of combustion air supplied to the engine.
An off-gas supply amount detection unit that detects the off-gas supply amount; and a concentration detection unit that detects a concentration of hydrogen and a concentration of methane contained in the off-gas supplied to the combustion unit;
The control unit is included in the off gas based on the off gas supply amount detected by the off gas supply amount detection unit, and the hydrogen concentration and the methane concentration detected by the concentration detection unit. The feed-forward control for obtaining the target combustion air amount for burning the combustion component and supplying the obtained target combustion air amount to the combustion section is performed.

  That is, the off-gas supply amount supplied to the combustion section, the concentration of hydrogen contained in the off-gas, and the concentration of methane are detected, and the target combustion air for burning the combustion components contained in the off-gas based on the detection results The feedforward control for obtaining the amount and supplying the obtained target combustion air amount to the combustion section is executed.

In other words, off-gas contains hydrogen, methane, and carbon monoxide as combustible components, but the amount of carbon monoxide contained in the off-gas is small and does not fluctuate greatly, so it is included in the off-gas. The amount of combustion air for burning carbon monoxide can be set to a constant value.
That is, generally, the reformed gas is supplied to the CO converter, the carbon monoxide contained in the reformed gas is converted to carbon dioxide, and the reformed reformed gas is supplied to the pressure fluctuation adsorption unit. Therefore, the amount of carbon monoxide contained in the off-gas is very small and does not vary greatly.

Therefore, the amount of combustion air supplied per unit amount of off-gas is determined based on the amount of combustion air determined according to the concentration of hydrogen, the amount of combustion air determined according to the concentration of methane, and the amount for burning carbon monoxide. It can be obtained as the sum of the amount of combustion air set to a constant value.
Then, the theoretical combustion air amount for burning the combustion components contained in the off gas can be obtained from the product of the combustion air amount supplied per unit amount of the obtained off gas and the off gas supply amount. The target combustion air amount can be obtained as a value obtained by multiplying the excess air amount (> 1) for completing the combustion with the use air amount.

  Accordingly, since an appropriate target combustion air amount is supplied to the combustion unit in order to burn the combustion component contained in the off gas, a large amount of heat is generated together with the combustion exhaust gas while appropriately burning the off gas in the combustion unit. Can be prevented from being wasted.

  In short, according to the characteristic configuration of the hydrogen production apparatus of the present invention, the amount of heat released together with the combustion exhaust gas can be reduced.

  The hydrogen production apparatus according to the present invention is further characterized in that the concentration detector includes a specific gravity detector that measures the specific gravity of the off gas, a hydrogen concentration detector that detects the hydrogen concentration, and the specific gravity of the off gas and the A methane concentration calculation unit for obtaining the methane concentration based on the hydrogen concentration is provided.

That is, based on the measured specific gravity of the off gas and the measured hydrogen concentration, the methane concentration calculation unit obtains the methane concentration.
In other words, the off-gas contains hydrogen, methane, and carbon monoxide as combustible components, and also contains nitrogen and carbon dioxide. The concentration of carbon monoxide and nitrogen contained in the off-gas is very small and Since it does not fluctuate greatly, it can be assumed to be constant.

  And the specific gravity of off gas is the product of the ratio of hydrogen in off gas and the specific gravity of hydrogen, the product of the ratio of methane in off gas and the specific gravity of methane, the product of the ratio of carbon dioxide in the off gas and the specific gravity of carbon dioxide. The product of the ratio of carbon monoxide in the off-gas and the specific gravity of carbon monoxide and the product of the ratio of nitrogen in the off-gas and the specific gravity of nitrogen. (Hereinafter, a formula that defines the relationship between the specific gravity of off-gas and the specific gravity of each component is referred to as a specific gravity relational expression.)

  The value obtained by adding the ratio of hydrogen in the off gas, the ratio of methane in the off gas, the ratio of carbon dioxide in the off gas, the ratio of carbon monoxide in the off gas, and the ratio of nitrogen in the off gas is 1. (Hereinafter, a formula that defines the relationship between the proportions of the components is referred to as a proportion relationship equation.)

Since the concentration of carbon monoxide and nitrogen is assumed to be constant, the product of the ratio of carbon monoxide in the off-gas and the specific gravity of carbon monoxide, and the ratio of nitrogen in the off-gas and nitrogen The product of the specific gravity is a constant, and similarly, the ratio of carbon monoxide in the off-gas and the ratio of nitrogen in the off-gas are constants.
Therefore, the methane concentration calculation unit uses the above-described specific gravity relational expression and the above-described ratio relational expression to determine the proportion of methane in the offgas based on the measured offgas specific gravity and the measured hydrogen concentration ( Equivalent to the concentration of methane).

  By the way, the methane concentration can be detected by using a methane concentration detection sensor that detects the methane concentration, but since off gas contains hydrogen as a combustion component, the methane concentration in the off gas is the methane concentration. Although it may be difficult to detect properly with the detection sensor, the concentration of methane can be determined appropriately by measuring the specific gravity of off gas and the concentration of hydrogen to determine the concentration of methane.

  In short, according to the further characteristic configuration of the hydrogen production apparatus of the present invention, the amount of heat released together with the combustion exhaust gas can be reduced by appropriately determining the concentration of methane.

A further characteristic configuration of the hydrogen production apparatus of the present invention is provided with a residual oxygen concentration detection unit that detects a residual oxygen concentration of the combustion exhaust gas discharged from the combustion unit,
The control unit is configured to execute feedback control for correcting the target combustion air amount so that the residual oxygen concentration detected by the residual oxygen concentration detection unit becomes a set target value. is there.

  In other words, feedback control is executed to detect the residual oxygen concentration of the flue gas discharged from the combustion section and correct the target combustion air amount so that the residual oxygen concentration becomes the set target value. The amount of combustion air to be performed is appropriately adjusted to an amount suitable for burning off-gas supplied to the combustion section while avoiding an excess or deficiency.

  In other words, the target combustion air amount for burning the combustion components contained in the offgas is determined based on the offgas supply amount supplied to the combustion section, the concentration of hydrogen in the offgas, and the concentration of methane in the offgas. The amount of combustion air supplied to the combustion unit is suitable for burning off-gas supplied to the combustion unit even when feedforward control for supplying the obtained target combustion air amount to the combustion unit is executed. Even in such a case, the amount of combustion air supplied to the combustion section should be appropriately adjusted to an amount suitable for burning off-gas supplied to the combustion section. Can do.

  In short, according to the further characteristic configuration of the hydrogen production apparatus of the present invention, the amount of combustion air supplied to the combustion section is appropriately adjusted to an amount suitable for burning off-gas supplied to the combustion section. be able to.

A further characteristic configuration of the hydrogen production apparatus according to the present invention is that, when the control unit detects that the off-gas shortage is detected by the off-gas shortage detection unit that detects the shortage of off-gas, the reformed gas is supplied. Configured to supply to the off-gas supply path,
The concentration detector is configured to detect the concentration of hydrogen and the concentration of methane contained in the offgas flowing downstream from the reformed gas supply location in the offgas supply path. is there.

  That is, immediately after increasing the supply amount of the raw material gas supplied to the reforming unit in order to increase the production amount of the product gas, the pressure fluctuation adsorption unit supplies the supply amount of the raw material gas supplied to the reforming unit. Therefore, the amount of off-gas discharged from the pressure fluctuation adsorption part heats the reforming reaction part of the reforming part to the reforming reaction temperature. It may be less than what you need to do.

  In such a case, since the shortage of offgas is detected by the offgas shortage detection unit and the reformed gas is supplied to the offgas supply path, the reforming reaction unit of the reforming unit is used for the reforming reaction. The raw material gas can be steam-reformed as appropriate while appropriately heating to the temperature.

  In addition, since the concentration detection unit is configured to detect the concentration of hydrogen and the concentration of methane contained in the off-gas flowing downstream from the reformed gas supply location in the off-gas supply path, Even in the state where the reformed gas is supplied to the off-gas supply path, the combustion component contained in the off-gas can be appropriately burned.

  In short, according to the further characteristic configuration of the hydrogen production apparatus of the present invention, the combustion component contained in the offgas can be appropriately combusted even when the reformed gas is supplied to the offgas supply path.

Overall view showing the hydrogen production system Schematic showing pressure fluctuation adsorption part The figure which shows the operation cycle of the pressure fluctuation adsorption part Explanatory drawing showing the operating state of the pressure fluctuation adsorption unit Explanatory drawing showing the operating state of the pressure fluctuation adsorption unit Explanatory drawing showing the operating state of the pressure fluctuation adsorption unit

Embodiment
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Overall configuration of hydrogen production equipment)
As shown in FIG. 1, the hydrogen production apparatus includes a reforming section A that reforms a raw material gas G that is a hydrocarbon gas such as natural gas or naphtha into a reformed gas having a large amount of hydrogen components, and the reforming section. A pressure fluctuation adsorbing portion B having an adsorption tower 1 that generates a product gas H by adsorbing an adsorbent component other than a hydrogen component from the reformed gas from A and discharged from the pressure fluctuation adsorbing portion B. An off-gas tank T that collects off-gas and a control unit M that controls the operation of the reforming unit A and the pressure fluctuation adsorption unit B are provided.

The reforming section A includes a steam mixing section J for mixing steam such that the ratio of the number of moles of steam mixed with the source gas G to the number of moles of carbon in the source gas is a target ratio (S / C), A reforming reaction tube 2 as a reforming reaction unit that reforms the gas G into a reformed gas having a large amount of hydrogen components by steam reforming, and a combustion unit that heats the reforming reaction tube 2 to a reforming reaction temperature. The burner 3 is provided.
An offgas supply path 4 for supplying offgas discharged from the pressure fluctuation adsorption section B to the burner 3 is provided, and the offgas tank T described above is disposed in the offgas supply path 4.
That is, the off gas stored in the off gas tank T is supplied to the burner 3, and the air supply path 5 for supplying combustion air to the burner 3 is provided.

A raw material gas supply line 7 for conveying the raw material gas G to the desulfurizer 6 is provided, and a mixing unit conveying line 9 for conveying the raw material gas G desulfurized by the desulfurizer 6 to the water mixing unit 8 is provided.
The water mixing unit 8 is configured to supply water conveyed through the water supply line 10 and mix it with the raw material gas G after the desulfurization treatment.

An evaporation transport line 12 for transporting the raw material gas G mixed with water in the water mixing unit 8 toward the evaporating heat exchange unit 11 is provided, and the water mixed with the raw material gas G is used for the evaporating heat exchange unit 11. It is comprised so that it may be heated and steamed.
Incidentally, in the present embodiment, the water vapor mixing section J includes the water mixing section 8 and the evaporation heat exchange section 11 as main parts.

Then, the raw material gas G heated so as to be in a state containing water vapor (a state where water vapor is mixed) in the evaporating heat exchange unit 11 is conveyed to the reforming reaction tube 2 through the reaction tube conveyance line 13. The reforming gas K having a large amount of hydrogen component is reformed by the steam reforming process.
In other words, the reforming reaction tube 2 is filled with the reforming catalyst and heated to the reforming reaction temperature (for example, 750 ° C.) by the burner 3 as described above, so that the hydrogen is formed by the steam reforming process. It is comprised so that it may modify | reform to the reformed gas K with many components.

  By the way, in the present embodiment, the combustion gas of the burner 3 flows toward the heat exchanger 11 for evaporation after heating the reforming reaction tube 2 and heats the heat exchanger 11 for evaporation. It is configured to be discharged through the passage 14.

A transformer transport line 16 for transporting the reformed gas K from the reforming reaction tube 2 to the CO converter 15 is provided, and carbon monoxide contained in the reformed gas K is converted into carbon dioxide by the CO converter 15. It is configured to be transformed.
Then, the reformed gas K that has been subjected to the transformation process in the CO transformer 15 is supplied to the pressure fluctuation adsorption section B through the reformed gas supply line 17.
The reformed gas supply line 17 includes a water separator 18 including a water cooler 18a and a steam / water separator 18b, and is configured to remove excess moisture from the reformed gas K.

(Details of pressure fluctuation adsorption section)
The pressure fluctuation adsorption unit B of the present embodiment includes a first adsorption tower 1A, a second adsorption tower 1B, and a third adsorption tower 1C as the adsorption tower 1.
As shown in FIG. 2, the lower part of each of the three adsorption towers 1 has a first supply branch passage 21 a and a second supply valve 20 b provided with a first supply valve 20 a with respect to the reformed gas supply line 17. The second supply branch passage 21b and the third supply branch passage 21c provided with the third supply valve 20c are connected.

Each adsorption tower 1 is filled with an adsorbent that adsorbs a component to be adsorbed other than the hydrogen component from the reformed gas K.
The adsorption target components other than the hydrogen component are carbon dioxide, carbon monoxide, methane, nitrogen and the like, and carbon monoxide and methane are combustible components.

  Further, the upper part of each of the three adsorption towers 1 is connected to the product gas discharge line 22 with a first discharge branch path 22a having a first discharge valve 23a and a second discharge valve having a second discharge valve 23b. The branch path 22b is connected via a third discharge branch path 22c having a third discharge valve 23c.

Further, the upper part of each of the three adsorption towers 1 is connected to the pressure equalizing line 24 by a first pressure equalizing branch path 24a provided with a first pressure equalizing valve 25a and a second pressure equalizing branch provided with a second pressure equalizing valve 25b. The passage 24b is connected via a third pressure equalizing branch 24c provided with a third pressure equalizing valve 25c.
A cleaning line 26 is provided for flowing the product gas H flowing through the product gas discharge line 22 to the pressure equalizing line 24, and a cleaning valve 27 is provided in the cleaning line 26.

  Furthermore, the lower part of each of the three adsorption towers 1 has a first off-gas branch path 28a having a first off-gas valve 29a and a second off-gas branch having a second off-gas valve 29b with respect to the off-gas discharge line 28. The off gas discharge line 28 is connected to the off gas tank T through the passage 28 b and the third off gas branch passage 28 c provided with the third off gas valve 29 c.

  As shown in FIG. 3, the pressure fluctuation adsorption unit B is controlled by the operation of the control unit M so that the adsorption process, the pressure equalization (discharge) process, the pressure reduction process, the washing process, the pressure equalization ( It is configured to generate a product gas H containing high-purity hydrogen gas from the reformed gas K by repeatedly performing an operation cycle including an acceptance process and a pressure-increasing process in a state where the operation phases are different. .

  That is, the first unit period in which the first adsorption tower 1A performs the adsorption process, the second unit period in which the second adsorption tower 1B performs the adsorption process, and the third unit period in which the third adsorption tower 1C performs the adsorption process are repeatedly executed. It is configured as follows.

  In addition, in the first unit cycle in which the first adsorption tower 1A performs the adsorption process, the first supply valve 20a and the first discharge valve 23a are opened, and the adsorption target component contained in the reformed gas K is removed. An adsorption process for adsorption is performed (see FIGS. 4 to 6), and the product gas H is discharged from the first adsorption tower 1 </ b> A to the product gas discharge line 22.

At the beginning of the first unit period, the second pressure equalizing valve 25b of the second adsorption tower 1B and the third pressure equalizing valve 25c of the third adsorption tower 1C are opened, and the internal gas of the third adsorption tower 1C is second adsorbed. A pressure equalizing step for supplying to the tower 1B is performed (see FIG. 4).
This pressure equalization step corresponds to a pressure equalization (discharge) step in the third adsorption tower 1C, and corresponds to a pressure equalization (acceptance) step in the second adsorption tower 1B.

  In the second adsorption tower 1B, when the pressure equalizing step is completed, the second pressure equalizing valve 25b is closed, and the second exhaust valve 23b is opened, so that the product gas H discharged from the first adsorption tower 1A is discharged. The boosting step to be introduced is executed until the first unit period ends (see FIGS. 5 and 6).

  In the third adsorption tower 1C, when the pressure equalizing step is completed, the third pressure equalizing valve 25c is closed and the third off-gas valve 29c is opened, so that the internal gas of the third adsorption tower 1C is removed from the off-gas discharge line 28. (See FIG. 5), the third pressure equalizing valve 25c and the cleaning valve 27 are then opened while the third off-gas valve 29c is open, and the product gas H is supplied from the cleaning line 26. A cleaning process is performed (see FIG. 6).

Further, the offgas discharged to the offgas discharge line 28 in the decompression process and the cleaning process is collected in the offgas tank T and then supplied to the burner 3 of the reforming section A through the offgas supply path 4.
The off gas contains carbon monoxide, methane, and hydrogen as combustible components.

The off-gas storage amount stored in the off-gas tank T is repeatedly increased and decreased with the operation of the pressure fluctuation adsorption unit B.
That is, in each of the first unit period, the second unit period, and the third unit period, the off-gas storage amount rapidly increases when the decompression process is started, and the off-gas storage amount also increases when the cleaning process is performed thereafter. When the pressure equalization step is performed, the off-gas storage amount repeatedly increases and decreases while the off-gas storage amount gradually decreases.

Incidentally, a pressure sensor PS that detects the internal pressure of the offgas tank T is provided as an offgas amount detection unit that detects the amount of offgas stored in the offgas tank T.
Further, as shown in FIG. 1, a replenishment line 19 is provided for supplying the reformed gas K from the reformed gas supply line 17 to the offgas tank T when the amount of offgas stored in the offgas tank T is insufficient. A supply valve 19A for opening and closing the supply line 19 is provided.
When the pressure sensor PS detects that the amount of off-gas stored in the off-gas tank T is insufficient, the supply valve 19A is opened, and the amount of off-gas stored in the off-gas tank T becomes the set reference amount. Until the pressure sensor PS detects that the reformed gas K is supplied to the off-gas tank T.
In the present embodiment, the pressure sensor PS functions as an off-gas shortage detection unit that detects a shortage of off-gas.

In the first unit cycle in which the first adsorption tower 1A performs the adsorption process, as described above, the pressure equalization (acceptance) process and the pressure increase process are sequentially executed for the second adsorption tower 1B, and the third adsorption tower 1C As for, a pressure equalization (discharge) step, a pressure reduction step, and a cleaning step are sequentially executed.
The second unit period in which the second adsorption tower 1B performs the adsorption process and the third unit period in which the third adsorption tower 1C performs the adsorption process are the same as the first unit period in which the first adsorption tower 1A performs the adsorption process. In the present embodiment, detailed description of the second unit period and the third unit period is omitted.

(Operation control of reforming section)
The source gas supply line 7 is provided with a source gas supply unit 30 that supplies the source gas G and allows the supply amount to be adjusted, and a source gas sensor 31 that detects the supply amount of the source gas G.
Then, based on the instruction information indicating the target production amount of the product gas H, the control unit M is to supply the raw material gas G of the target raw material gas supply amount necessary for producing the target production gas amount of the product gas H. The operation of the source gas supply unit 30 is controlled.
That is, the operation of the raw material gas supply unit 30 is controlled such that the supply amount of the raw material gas G detected by the raw material gas sensor 31 becomes the target raw material gas supply amount.

  Incidentally, in the present embodiment, the raw material gas supply unit 30 supplies the raw material gas G with the compressor 30a and the flow rate at which a part of the raw material gas G supplied by the compressor 30a is returned to the upstream side of the compressor 30a. It is comprised in the form provided with the control valve 30b.

The water supply line 10 supplies water treated by the water treatment unit 32 to pure water to the water mixing unit 8. The water supply line 10 includes a water supply pump 33 for supplying water, and a water supply. A water flow rate sensor 34 that detects the flow rate of water supplied through the line 10 and a water flow rate adjustment valve 35 that adjusts the water supply amount are provided.
The water supply pump 33 is equipped with a pressure control valve 33a for controlling the water supply pressure to a set pressure.

Then, the control unit M sets the target ratio (S / C), which is the ratio of the number of moles of water vapor supplied to the source gas G to the number of moles of carbon in the source gas G, as a reference operation ratio (for example, 3.0 ), The operation of the water flow control valve 35 is controlled.
That is, in a state in which the raw material gas G is supplied at the target raw material supply amount, a target water supply amount that makes the target ratio (S / C) the reference operation ratio (for example, 3.0) is obtained, and the water flow sensor The operation of the water flow rate adjustment valve 35 is controlled so that the flow rate detected at 34 becomes the target water supply amount.

(Burner combustion control)
A temperature sensor TS for detecting the internal temperature of the reforming reaction tube 2 is provided.
The off gas supply path 4 includes an off gas flow sensor 36 (an example of an off gas supply detection unit) that detects an off gas flow corresponding to the off gas supply supplied to the burner 3, and an off gas flow control valve 37 that adjusts the off gas flow. Is provided.
The air supply path 5 is provided with a blower 38 that can supply air and adjust the supply amount, and an air flow rate sensor 39 that detects the amount of air flowing through the air supply path 5.

The control unit M controls the off gas supply amount for supplying off gas to the burner 3 and heats the combustion air to the burner 3 in order to heat the reforming reaction tube 2 to the reforming reaction temperature (for example, 750 ° C.). The combustion air supply amount to be supplied is controlled.
That is, the control unit M obtains the target offgas supply amount to be supplied to the burner 3 based on the detected temperature detected by the temperature sensor TS and the reforming reaction temperature, and is detected by the offgas flow rate sensor 36. The operation of the off gas flow rate adjustment valve 37 is controlled so that the off gas flow rate becomes the target off gas supply amount.

  Further, the control unit M obtains a target combustion air amount necessary for burning off gas of the target off gas supply amount so that the air amount detected by the air flow sensor 39 becomes the target combustion air amount. Further, the operation of the blower 38 is controlled.

(Details of target combustion air volume)
Next, a process for obtaining the target combustion air amount by the control unit M will be described.
A concentration detector N for detecting the concentration of hydrogen and the concentration of methane contained in the off-gas supplied to the burner 3 is provided.
Then, the control unit M is included in the off gas based on the off gas flow rate (off gas supply amount) detected by the off gas flow rate sensor 36 and the hydrogen concentration and the methane concentration detected by the concentration detection unit N. The feed-forward control for obtaining the target combustion air amount for burning the combustion components and supplying the obtained target combustion air amount to the burner 3 is executed.

  That is, in this embodiment, assuming that the concentration of carbon monoxide is constant, the amount of combustion air for hydrogen obtained according to the concentration of hydrogen is determined as the amount of combustion air supplied per unit amount of offgas. And the amount of combustion air for methane determined according to the concentration of methane and the amount of combustion air for carbon monoxide set to a constant value for burning carbon monoxide. .

By the way, the amount of oxygen required to burn a unit amount of hydrogen is half the amount of hydrogen of a unit amount of hydrogen, and the amount of air that is five times the amount of oxygen burns a unit amount of hydrogen. The amount of combustion air required for the combustion can be made.
Similarly, the amount of oxygen required to burn a unit amount of methane is twice the amount of oxygen as the unit amount of methane, and the amount of air that is five times the oxygen amount burns the unit amount of methane. The amount of combustion air required for the combustion can be made.
Furthermore, the amount of oxygen necessary for burning the unit amount of carbon monoxide is ½ the amount of oxygen of the unit amount of carbon monoxide, and the amount of air five times the amount of oxygen is reduced to one unit amount. The amount of combustion air required for burning carbon oxide can be obtained.

  Then, the theoretical amount of combustion air for burning the combustion components contained in the offgas is determined by the product of the amount of combustion air supplied per unit amount of offgas and the offgas flow rate (offgas supply amount). A value obtained by multiplying the combustion air amount by an excess coefficient (> 1) for completing combustion is set as the target combustion air amount.

In addition, a residual oxygen concentration detection sensor 43 as a residual oxygen concentration detection unit that detects the residual oxygen concentration of the combustion exhaust gas discharged from the burner 3 is provided in the exhaust gas passage 14.
The control unit M is configured to execute feedback control for correcting the target combustion air amount so that the residual oxygen concentration detected by the residual oxygen concentration detection sensor 43 becomes the set target value.
In the present embodiment, a target range as a set target value is set, and as a feedback control, when the residual oxygen concentration detected by the residual oxygen concentration detection sensor 43 deviates from the upper limit value or the lower limit value of the target range, the target range is set. A control for decreasing the combustion air amount by a set amount and a control for increasing the set amount are executed.

(Details of concentration detector)
In the present embodiment, the concentration detection unit N includes a hydrogen concentration detection sensor 40 as a hydrogen concentration detection unit that detects the concentration of hydrogen, a specific gravity detection sensor 41 as a specific gravity detection unit that measures the specific gravity of off gas, and an off gas It is set to the form provided with the methane density | concentration calculating part 42 which calculates | requires the density | concentration of methane based on the density of specific gravity and hydrogen.

  In other words, the off-gas contains hydrogen, methane, and carbon monoxide as combustible components, and also contains nitrogen and carbon dioxide. The concentration of carbon monoxide and nitrogen contained in the off-gas is very small and Since it does not vary greatly, it is assumed to be constant.

  The specific gravity of off-gas is the product of the ratio of hydrogen in off-gas and the specific gravity of hydrogen, the product of the ratio of methane in off-gas and the specific gravity of methane, the product of the ratio of carbon dioxide in the off-gas and the specific gravity of carbon dioxide. The product of the ratio of carbon monoxide in the off-gas and the specific gravity of carbon monoxide and the product of the ratio of nitrogen in the off-gas and the specific gravity of nitrogen. (Hereinafter, a formula that defines the relationship between the specific gravity of off-gas and the specific gravity of each component is referred to as a specific gravity relational expression.)

  The value obtained by adding the ratio of hydrogen in the off gas, the ratio of methane in the off gas, the ratio of carbon dioxide in the off gas, the ratio of carbon monoxide in the off gas, and the ratio of nitrogen in the off gas is 1. (Hereinafter, a formula that defines the relationship of the ratio of each component is referred to as a ratio relational expression.)

  Since the concentration of carbon monoxide and nitrogen is assumed to be constant, the product of the ratio of carbon monoxide in the off gas and the specific gravity of carbon monoxide, and the ratio of nitrogen in the off gas and nitrogen The product of the specific gravity is a constant, and similarly, the ratio of carbon monoxide in the off-gas and the ratio of nitrogen in the off-gas are constants.

Therefore, the methane concentration calculation unit 42 uses the above-described specific gravity relational expression and the above-described ratio relational expression to determine the proportion of methane in the offgas based on the offgas specific gravity and the hydrogen concentration (corresponding to the methane concentration). Is configured to ask for.
In addition, the methane concentration calculation part 42 is comprised using the control part M in this embodiment.

In the present embodiment, the hydrogen concentration detection sensor 40 and the specific gravity detection sensor 41 are configured to detect the off gas supplied from the off gas tank T.
Therefore, when the off gas is insufficient, the hydrogen concentration detection sensor 40 and the specific gravity detection sensor 41 detect the off gas flowing downstream from the supply location of the reformed gas K in the off gas supply path 4. Therefore, an appropriate target combustion air amount can be obtained also when the offgas is insufficient and the reformed gas K is supplied to the offgas supply path 4.

[Another embodiment]
Next, another embodiment is listed.
(1) In the above embodiment, the pressure fluctuation adsorption part B is exemplified as having three adsorption towers 1, but the present invention has two or four or more adsorption towers 1 as the pressure fluctuation adsorption part B. The present invention can also be applied to the case where the configuration is provided with.

(2) In the above embodiment, the pressure fluctuation adsorbing part B is exemplified as one configured to perform the cleaning process. However, in the present invention, the pressure fluctuation adsorbing part B is replaced with a cleaning process by a vacuum pump. The present invention can also be applied to a case where a suction process for sucking the inside of the adsorption tower 1 is performed.

(3) In the said embodiment, after mixing the water vapor | steam with the raw material gas G, the case where it was comprised so that the mixed water might be evaporated in the heat exchange part 11 for evaporation was illustrated. However, the water vapor mixing section J may be configured and implemented in a form in which water vapor generated in advance is mixed with the raw material gas G.

(4) In the above-described embodiment, the case where the pressure sensor PS that detects the internal pressure of the offgas tank is provided as the offgas shortage detection unit. However, as the offgas shortage detection unit, the flow rate of the offgas recovered in the offgas tank T To calculate the integrated amount of off-gas recovered in the off-gas tank T, integrate the flow rate of off-gas discharged from the off-gas tank T, and determine the integrated amount of off-gas discharged from the off-gas tank T, You may implement in the form which detects the shortage of off gas from the collection | recovery integrated amount and the discharge | emission integrated amount.

(5) In the above embodiment, the case where the methane concentration is calculated by the methane concentration calculation unit 42 based on the concentration of hydrogen and the specific gravity of off-gas is exemplified. You may implement.

(6) In the above embodiment, the amount of combustion air supplied per unit amount of off gas is obtained, and the combustion component contained in the off gas is burned by the product of the amount of combustion air and the off gas flow rate (off gas supply amount). The amount of theoretical combustion air to be obtained is calculated, but is included in the amount of hydrogen combustion air for burning the amount of hydrogen contained in the amount of off gas supplied to the burner 3 and the amount of off gas supplied to the burner 3 Included in the off-gas by adding the combustion air amount for methane that burns the amount of methane produced and the combustion air amount for carbon monoxide that burns the amount of carbon monoxide contained in the off-gas supply amount supplied to the burner 3 You may implement in the form which calculates | requires the air quantity for theoretical combustion for burning the combustion component to be burned.

  Note that the configurations disclosed in the above-described embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with the configurations disclosed in the other embodiments as long as no contradiction arises. The embodiment disclosed in this specification is an exemplification, and the embodiment of the present invention is not limited to this. The embodiment can be appropriately modified without departing from the object of the present invention.

DESCRIPTION OF SYMBOLS 1 Adsorption tower 2 Reforming reaction part 3 Combustion part 4 Off gas supply path 36 Off gas supply amount detection part 40 Hydrogen concentration detection part 41 Specific gravity detection part 42 Methane concentration calculation part 43 Residual oxygen concentration detection part A Reformation part B Pressure fluctuation adsorption part G Raw material gas H Product gas K Reformed gas M Control unit PS Off-gas shortage detection unit

Claims (4)

A reforming section having a reforming reaction section for reforming a raw material gas, which is a hydrocarbon-based gas, to a reformed gas having a large amount of hydrogen components by steam reforming; and a reforming section having a combustion section for heating the reforming reaction section; A pressure fluctuation adsorption part having an adsorption tower for producing a product gas by adsorbing an adsorption target component other than a hydrogen component contained in the reformed gas from a mass part to an adsorbent, and discharged from the pressure fluctuation adsorption part An off-gas supply path for supplying off-gas to the combustion section;
A control unit for controlling the operation of the combustion unit controls an off gas supply amount for supplying the off gas to the combustion unit and heats combustion air to the combustion unit so as to heat the reforming reaction unit to a reforming reaction temperature. A hydrogen production apparatus configured to control a combustion air supply amount to be supplied to
An off-gas supply amount detection unit that detects the off-gas supply amount; and a concentration detection unit that detects a concentration of hydrogen and a concentration of methane contained in the off-gas supplied to the combustion unit;
The control unit is included in the off gas based on the off gas supply amount detected by the off gas supply amount detection unit, and the hydrogen concentration and the methane concentration detected by the concentration detection unit. A hydrogen production apparatus configured to perform feedforward control for obtaining a target combustion air amount for burning a combustion component and supplying the obtained target combustion air amount to the combustion unit.   The concentration detection unit obtains the methane concentration based on the specific gravity detection unit that measures the specific gravity of the off gas, the hydrogen concentration detection unit that detects the concentration of hydrogen, and the specific gravity of the off gas and the concentration of hydrogen. The hydrogen production apparatus according to claim 1, further comprising a methane concentration calculation unit. A residual oxygen concentration detection unit for detecting the residual oxygen concentration of the combustion exhaust gas discharged from the combustion unit is provided;
The control unit is configured to execute feedback control for correcting the target combustion air amount so that the residual oxygen concentration detected by the residual oxygen concentration detection unit becomes a set target value. The hydrogen production apparatus according to 1 or 2. The controller is configured to supply the reformed gas to the offgas supply path when it is detected that the offgas is insufficient by an offgas shortage detector that detects the shortage of offgas.
The concentration detector is configured to detect a concentration of the hydrogen and a concentration of the methane contained in the off-gas flowing downstream from the reformed gas supply location in the off-gas supply path. The hydrogen production apparatus according to any one of 1 to 3.

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