Hydrogen production device and hydrogen production method

Abstract

Provided is a hydrogen production device and method that can operate the hydrogen production device at a lower load and achieve operation without sending product hydrogen outside the system. [Solution] Purified hydrogen gas G from the hydrogen purification device 40 4 A part of the raw material is introduced into the raw material introduction line L 1 Recycle hydrogen line L 11 During normal operation of hydrogen production, the recycle hydrogen line L 11 The purified hydrogen gas recycled in the desulfurizer 14 is supplied as the amount of hydrogen required for the hydrogenation reaction in the desulfurizer 14, and during low-load idling operation, the recycled hydrogen line L 11 Recycled hydrogen gas (recycled hydrogen gas for idle operation) 4b ) is converted into hydrogen for the hydrogenation reaction in the desulfurizer 14 (hydrogenation recycle hydrogen G 4a ) amount is supplied in an amount 4 to 10 times the amount.

Description

[Technical field]

[0001] The present invention relates to a hydrogen production device and a hydrogen production method. [Background technology]

[0002] Conventionally, hydrogen production apparatuses are known as those that supply a hydrocarbon gas, such as natural gas or LPG, as a raw material gas together with steam to a reformer and react with a reforming catalyst to generate a hydrogen-containing gas (see, for example, Patent Documents 1 to 3). Hydrogen production apparatuses for industrial use are often operated continuously day and night because the product hydrogen that is continuously produced is generally consumed. Furthermore, continuous operation day and night increases efficiency, which ultimately reduces the unit price of hydrogen. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-030655 A [Patent Document 2] JP 2016-000675 A [Patent Document 3] JP 2023-19891 A Summary of the Invention [Problem to be solved by the invention]

[0004] Some users of hydrogen production equipment may be required to reduce the amount of hydrogen sent to zero without shutting down the equipment at night or on holidays, since hydrogen production is not required at night or on holidays. If the hydrogen production equipment is shut down when hydrogen is not needed, it takes several hours to half a day to restart, which means that the equipment cannot be used immediately the next day, causing a problem in that it interferes with the user's production operations.

[0005] Furthermore, in conventional operating methods, even when operating at the minimum load in order to suppress the amount of hydrogen generated as much as possible, the produced hydrogen is still generated and must be vented or incinerated, resulting in a loss of product hydrogen. Therefore, there is a strong demand for a hydrogen production device that can be operated at a lower load and that does not send product hydrogen outside the system.

[0006] The present invention has been made in consideration of the above problems, and aims to provide a hydrogen production apparatus and a hydrogen production method that can operate the hydrogen production apparatus at a lower load and without sending product hydrogen outside the system. [Means for solving the problem]

[0007] A hydrogen production device according to a first aspect of the present invention comprises: a raw material introduction line for introducing a raw material gas; a desulfurizer provided in the raw material introduction line for desulfurizing the sulfur content in the raw material gas; a reformer for reforming the desulfurized raw material gas; a transformer that transforms the reformed gas after reforming in the reformer; a hydrogen purification device that purifies the converted gas after the conversion by the converter; A hydrogen production apparatus comprising: a recycle hydrogen line for recycling a portion of the purified hydrogen gas from the hydrogen purification device to the raw material introduction line on the inlet side of the compressor, During normal operation of hydrogen production, the amount of purified hydrogen gas recycled through the recycle hydrogen line is hydrogen required for the hydrogenation reaction in the desulfurizer, and During low-load idling operation, the amount of purified hydrogen gas recycled through the recycle hydrogen line is 4 to 10 times the amount of hydrogen used in the hydrogenation reaction in the desulfurizer.

[0008] A hydrogen production method according to a second aspect of the present invention includes a raw material introduction line for introducing a raw material gas; a desulfurizer provided in the raw material introduction line for desulfurizing the sulfur content in the raw material gas; a reformer for reforming the desulfurized raw material gas; a transformer that transforms the reformed gas after reforming in the reformer; a hydrogen purification device that purifies the converted gas after the conversion by the converter; a recycle hydrogen line for recycling a portion of the purified hydrogen gas from the hydrogen purification device to the raw material introduction line on the inlet side of the compressor; A hydrogen production device comprising: During normal operation of hydrogen production, the amount of purified hydrogen gas recycled through the recycle hydrogen line is adjusted to supply hydrogen necessary for the hydrogenation reaction in the desulfurizer, During low-load idling operation, the amount of purified hydrogen gas recycled through the recycle hydrogen line is 4 to 10 times the amount of hydrogen used in the hydrogenation reaction in the desulfurizer. Effect of the Invention

[0009] According to the present invention, the amount of product hydrogen sent outside the hydrogen production apparatus is substantially zero, which not only significantly reduces the net raw material load but also suppresses the fuel consumption of the reformer burner.

[0010] In addition, by increasing the amount of recycled hydrogen sent to the raw gas side during idle operation by 4 to 10 times the normal amount and using the surplus hydrogen produced as fuel for the reformer burner, the amount of hydrogen produced is essentially zero. By using the surplus hydrogen produced as fuel during this idle operation, it is possible to significantly reduce the consumption of hydrocarbon fuel gas. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a hydrogen production device according to an embodiment of the present invention. [Diagram 2] 1 is a schematic diagram of a hydrogen production device according to an embodiment of the present invention. [Diagram 3] 1 is a schematic diagram of a hydrogen production device according to an embodiment of the present invention. [Figure 4] FIG. 2 is another schematic diagram of the hydrogen production device according to the present embodiment of the present invention. [Diagram 5] FIG. 4 is a schematic diagram showing the amount of recycled hydrogen when transitioning from normal operation to idle operation according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the following mode for carrying out the invention (hereinafter, referred to as the embodiment). Furthermore, the components in the following embodiment include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components disclosed in the following embodiment can be appropriately combined. In the embodiments of this specification, the same components are denoted by the same reference numerals throughout. Note that this embodiment is merely an example of the configuration of the present invention, and various design changes can be made without departing from the scope of the claims.

[0013] Fig. 1 is a schematic diagram of the normal operation of the hydrogen production apparatus of this embodiment. Fig. 2 is a schematic diagram of the transition state of the hydrogen production apparatus of this embodiment to idle operation. Fig. 3 is a schematic diagram of the idle operation state of the hydrogen production apparatus of this embodiment. Fig. 4 is another schematic diagram of the idle operation state of the hydrogen production apparatus of this embodiment. Fig. 5 is a schematic diagram showing the amount of recycled hydrogen when transitioning from normal operation to idle operation according to the present invention.

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments of this specification, the same components are denoted by the same reference numerals throughout.

[0015] First, the hydrogen production device will be described. Fig. 1 is a system diagram showing an outline of a hydrogen production device according to an embodiment of the present invention. As shown in FIG. 1, the hydrogen production device 100-1 of this embodiment includes, as its main devices, a desulfurizer 14, a reformer 20 equipped with a reformer tube 21, a converter 30, a pressure swing adsorption (hereinafter also referred to as "PSA") unit 40, and an off-gas holder 45. In Figure 1, the reference numerals 10 and 12 indicate a compressor, 11 a raw material flow rate meter, 12 a raw material flow rate control valve, 13 a raw material preheater, 15 a raw material heater, 22 a combustion burner, 23 an air blower, 24 a gas boiler, 31 a gas boiler / gas cooler, 41 a product hydrogen delivery pressure meter, 42 a product hydrogen delivery pressure control valve, 43 a product hydrogen gas delivery valve, 44 a fuel hydrogen gas shutoff valve, 46 an off-gas pressure meter, 47 an off-gas pressure control valve, 48 a recycled hydrogen flow rate meter, 49 a recycled hydrogen flow rate control valve, 50 a product hydrogen diffusion shutoff valve, G1 a raw material gas, G2 a reformed gas, G3 a converted gas, G4 a refined gas, and G5 a off-gas.

[0016] As shown in FIG. 1, the hydrogen production apparatus 100-1 according to the present embodiment includes a raw material introduction line L1 for introducing a raw material gas G1, a desulfurizer 14 provided in the raw material introduction line L1 for desulfurizing the sulfur (S) content in the raw material gas G1, a reformer 20 for reforming the raw material gas after desulfurization, a shift converter 30 for transforming the reformed gas G2, and a hydrogen purification device (e.g., a PSA unit) 40 for purifying the transformed gas G3. The hydrogen production apparatus includes a recycle hydrogen line L1 for recycling a part of the purified gas G4 from the hydrogen purification device 40 to the raw material introduction line L1 on the inlet side of the compressor 10. 11 It is equipped with the following:

[0017] During normal operation of hydrogen production, the recycle hydrogen line L 11 The purified hydrogen gas recycled in the above step is supplied as the amount of hydrogen required for the hydrogenation reaction in the desulfurizer 14. In addition, during low-load standby operation (idling), the recycle hydrogen line L 11 Recycled hydrogen gas (recycled hydrogen gas for idle use) 4b ) is converted into hydrogen for the hydrogenation reaction in the desulfurizer 14 (hydrogenation recycle hydrogen G 4a The amount of hydrogen to be supplied is 4 to 10 times the amount of hydrogen for idle use. 4b The amount of recycled hydrogen for hydrogenation is G 4a If "0.05 times the amount of raw gas" is taken as 1 (normal), then the amount is 4 to 10 times that amount.

[0018] The desulfurizer 14 removes sulfur components contained as odorants in hydrocarbon fuels such as city gas and LPG. Since the sulfur components become a catalyst poison for the reforming catalyst and conversion catalyst of the reformer 20 used in the subsequent process, the sulfur components contained in the raw material gas G1 are removed in advance by the desulfurizer 14.

[0019] Specifically, the desulfurizer 14 is configured with a flow path filled with a hydrodesulfurization catalyst composed of a hydrogenation catalyst such as a Co-Mo or Ni-Mo type, and a ZnO-based desulfurization catalyst that adsorbs hydrogen sulfide. The desulfurizer 14 supplies the raw material gas G1 and hydrogen to cause a hydrogenation (hereinafter referred to as "hydrogenation") reaction, converting the sulfur components into hydrogen sulfide, and incorporating the hydrogen sulfide into zinc oxide to form zinc sulfide, thereby removing the sulfur components.

[0020] The reaction formula for this hydrodesulfurization is as shown in the following reaction formulas (1) and (2). CmHnS+H2 → CmHn+H2S (1) H2S+ZnO → H2O+ZnS (2)

[0021] The desulfurizer 14 may be one that performs desulfurization using an adsorbent for sulfur compounds that reacts at room temperature or high temperature, instead of the hydrogenation reaction as in the present embodiment. In addition, in the case of the raw material gas G1 that does not contain sulfur components, it is not necessary to provide the desulfurizer 14.

[0022] The reformer 20 adds steam (or pure water) to the raw material gas G1 and brings it into contact with a reforming catalyst (hereinafter referred to as the "catalyst") described below at high temperatures (for example, 650°C to 900°C) to reform the raw material gas G1 and generate a reformed gas G2 such as hydrogen and carbon monoxide. The reaction formulas of this steam reforming are as shown in the following reaction formulas (3) and (4). CmHn+mH2O→mCO+(m+n / 2)H2...(3) CO+3H2←→CH4+H2O (4)

[0023] These steam reforming reactions are endothermic reactions, and the steam / carbon ratio in the mixture is preferably about 3:1 to prevent carbon deposition on the catalyst surface.

[0024] The reformer 20 is provided with reforming tubes 21 filled with a catalyst for steam reforming. A plurality of the reforming tubes 21 are arranged and housed inside the reactor.

[0025] The reformer 20 converts a part G of the raw material gas G1 into 1a Fuel gas F (offgas G5) from a PSA unit 40 (described later) is supplied to the burner 22 together with air from an air blower 23, and the reforming tubes 21 in the reaction furnace are heated to a predetermined temperature (for example, about 950° C.).

[0026] The shift converter 30 reacts the carbon monoxide in the reformed gas G2 sent from the reformer 20 with water vapor to generate more hydrogen H2. The reaction formula for this CO shift conversion is shown in the following reaction formula (5). CO+H2O←→CO2+H2 (5)

[0027] In the converter 30, a catalyst such as an Fe-Cr type, a Cu-Zn type, or a Pt type is used depending on the reaction temperature, for example, from 200°C to 500°C.

[0028] The PSA unit 40, which is a hydrogen purification device, uses an adsorbent to adsorb impurity gases other than hydrogen H2, such as carbon monoxide, carbon dioxide, methane, and water vapor, and can separate purified gas G4 containing only hydrogen H2 from the converted gas G3, ultimately achieving a hydrogen concentration of, for example, approximately 99.999%. Off-gas G5 generated by this hydrogen purification device 40 may be used as fuel for the burner 22 for heating the reformer 20. Note that the PSA unit 40 returns the gas to a state where it can be adsorbed again by the process of desorbing the impurities described above. The produced hydrogen is pressurized, for example, to about 20 MPa by a hydrogen compressor (not shown), and then sent to a shipping facility. In addition, when there is little demand for hydrogen, the system allows for idle operation according to the present invention in order to maintain the temperature of the catalyst, and by using the generated hydrogen as a heat source during idle operation, it is possible to reduce the amount of raw material gas used.

[0029] Furthermore, the hydrogen production device 100-1 is provided with the following components: (1) Raw material gas G1 from a raw material supply source is compressed by a compressor 10, and a raw material flow rate control valve 12 is provided in a raw material introduction line L1. (2) The reformed gas G2 reformed by the reforming tubes 21 of the reformer 20 is supplied to the transformer 30 via a reformed gas line L2. (3) The shifted gas G3 from the shift converter 30 is sent via a shifted gas line L3 to a PSA unit 40, which is a hydrogen purification device. The sent shifted gas G3 is purified in the PSA unit 40. (4) A hydrogen extraction line L4 for extracting the refined gas (hydrogen H2) G4 is provided on the outlet side of the hydrogen purification device 40. This hydrogen extraction line L4 is equipped with a product hydrogen delivery pressure gauge 41, a product hydrogen delivery pressure regulating valve 42, and a product hydrogen gas delivery valve 43. (5) From the raw material supply source, fuel gas G is supplied to the burner 22 of the reformer 20. 1a Fuel line L supplies 1-1 is provided. (6) An off-gas line L for supplying off-gas G5 is connected from the hydrogen purification device 40 to the burner 22. 12 The off-gas line L 12 is provided with an off-gas holder 45 and an off-gas pressure regulating valve 47. (7) On the downstream side of the desulfurizer 14, a pure water supply line L 20 is connected to this pure water supply line L 20 The pure water supply line L is provided with a pure water control valve (not shown). 20 The deionized water is converted into steam by a heat exchanger (not shown) provided in the deionized water supply unit. Note that steam may be directly supplied from another source.

[0030] With this configuration, the hydrogen production device 100-1 converts raw material gas (hereinafter referred to as “reforming raw material”) G 1b is sent to the desulfurizer 14 to remove the sulfur components, and then the desulfurized reforming raw material G 1b The hydrogen H2 is supplied to the reformer 20 together with pure water (steam). The reformer 20 generates a reformed gas G2 containing hydrogen H2, sends the reformed gas G2 to the transformer 30, and further transforms the reformed gas G2 to produce a transformed gas G3. Thereafter, liquid is separated from the transformed gas G3 by a gas-liquid separator (not shown), and the PSA unit 40 adsorbs everything other than the hydrogen H2 as off-gas G5, thereby producing a large amount of product hydrogen H2, which is the refined gas G4.

[0031] The hydrogen production device 100-1 has the above-mentioned equipment configuration. Hydrocarbons such as methane and LPG are used as the raw material gas G1, and a part of the raw material gas G is used as the fuel gas G 1a Recycled hydrogen (H2) for hydrogenation G 4a The gas mixed with this is called reforming raw material G 1b The raw material gas G1 is then compressed to a predetermined pressure (for example, about 0.9 MPa) by a compressor 10, and the flow rate is adjusted by a raw material flow rate meter 11 and a raw material flow rate control valve 12. The raw material gas G1 is then heated to a predetermined temperature by a raw material preheater 13, and the raw material gas G2 is then heated to a predetermined temperature by a raw material preheater 13. 1a Reformed raw material G 1b is heated.

[0032] Then, it passes through the desulfurizer 14, is mixed with pure water or steam, is heated in the raw material heater 15, and is converted into the reforming raw material G in the reforming tube 21. 1b is converted into hydrogen-rich reformed gas G2 through a reforming reaction.

[0033] Next, the reformed gas G2 undergoes heat exchange in the gas boiler 24, and then passes through the shift converter 30 to further increase the hydrogen content of the reformed gas G2, which is a hydrogen-rich gas, and then through the PSA unit 40 to produce a refined gas G4 of high-purity hydrogen.

[0034] Part of this refined gas G4 is recycled hydrogen G 4a (The flow rate is fixed at 0.05 times the raw material flow rate at rated load.) This recycled hydrogen G 4a The feed rate of the hydrogen production system is preferably set to 0.05 times the feed rate at rated load. Usually, this is fixed for each hydrogen production system.

[0035] This recycled hydrogen G 4a The flow rate of the off-gas G5, which is an impurity gas captured in the PSA unit 40, is adjusted by a recycled hydrogen flow meter 48 and a recycled hydrogen flow control valve 49, and the off-gas G5 is used as fuel for the burner 22 of the reformer 20 via an off-gas holder 45.

[0036] In the idle operation of this embodiment, the amount of recycled hydrogen is set to 4 to 10 times the raw material flow rate at the rated load, so that most of the generated hydrogen is recycled hydrogen G 4a It will be used as reforming raw material G 1b The raw material composition becomes hydrogen-rich, making it possible to significantly reduce the consumption of raw material gas.

[0037] The feed flow rate meter 11 of this apparatus measures the flow rate of the supplied hydrocarbon feed gas G1 minus the amount of fuel used plus the amount of recycled hydrogen, and the flow rate is adjusted by the feed flow rate control valve 12 in accordance with the load on the apparatus. For example, when idle operation is performed at a load of 25% of the rated load, the adjusted flow rate is equivalent to a load of 25%, but the proportion of the recycled hydrogen in the flow rate is high, so the amount of hydrocarbon feedstock is reduced.

[0038] The operating state during normal operation of hydrogen production will be described with reference to FIG. In the present invention, normal operation refers to operation at a load of 30 to 100%, and low load operation refers to operation at a load of less than 30%.

[0039] First, as shown in FIG. 1, during normal operation of hydrogen production, the recycle hydrogen line L 11 The purified hydrogen gas recycled in the desulfurizer 14 is converted into hydrogen (recycled hydrogen for hydrogenation G 4aThis flow rate is fixed at 0.05 times the raw material flow rate at rated load.

[0040] Figure 2 shows low-load standby operation (idling: load less than 30%). 11 Recycled hydrogen gas (recycled hydrogen gas for idle operation) 4b ) is converted into hydrogen for the hydrogenation reaction in the desulfurizer 14 (hydrogenation recycle hydrogen G 4a The amount of the feed is increased gradually as described below.

[0041] In Figure 3, during low-load standby operation (idling: load less than 30%), the increase in recycled hydrogen is completed and surplus hydrogen is sent out. Of the produced hydrogen G4, only 10% is recycled hydrogen G for hydrogenation. 4a Hydrogen that is not used as fuel, i.e., surplus hydrogen (off-gas introduced hydrogen G 4c ) is the surplus hydrogen introduction line L 13 The off-gas G5 is transported to the off-gas holder 43 by the suction port 44 and mixed with the off-gas G5 to be used as the fuel F for the burner 22, thereby making it possible to reduce the consumption of the hydrocarbon fuel gas.

[0042] As described above, with the operating method of the present invention, the amount of product hydrogen (G4) sent outside the device is essentially zero, which not only significantly reduces the net raw material load, but also makes it possible to suppress fuel consumption.

[0043] In addition, the idle recycle hydrogen G 4b By increasing the amount of hydrogen sent to the raw gas side by 4 to 10 times the usual amount and using the surplus hydrogen produced as fuel, the amount of hydrogen produced will essentially be zero. In this way, during idling, the excess hydrogen (G 4c ) as the fuel gas F, it is possible to significantly reduce the consumption of hydrocarbon fuel gas.

[0044] Unlike the conventional system, the system is not completely shut down during idle operation, and because the system is in idle operation, it is possible to quickly return to normal operation.

[0045] Raw material gas G1 is recycled hydrogen G for idle use 4b As a result of the introduction of reformed raw material G 1b The hydrogen content of the total reforming feedstock G 1b As a result, even during low load idling, it becomes possible to measure the flow rate with the raw material flow rate meter 11 and control the flow rate with the adjustment valve.

[0046] In addition, the raw gas G1 is recycled hydrogen G 4b As a result of the introduction of the feed preheater 13, the feed heater 15, and the reformer 20, the flow rate on the process side becomes faster, making it possible to avoid overheating.

[0047] The raw material load is reduced so that only a small amount of hydrogen is produced, and the surplus hydrogen gas is used as fuel for the reformer.

[0048] Idle operation can be achieved without making major changes to the equipment or changing any special load equipment.

[0049] In order to reduce hydrogen emission to zero during the increase in recycled hydrogen, the fuel hydrogen gas shutoff valve 44 is immediately opened to close the off-gas line L 12 If it is introduced into the engine, there is a risk that the fuel will become excessive and the thermal balance will not be maintained.

[0050] Therefore, in this embodiment, as shown in FIG. 4b Started increasing the amount of recycled hydrogen for idle 4b After the increase in the amount of hydrogen reaches a specified amount, as shown in FIG. 3, the fuel hydrogen gas cutoff valve 44 is controlled to be opened and the product hydrogen diffusion cutoff valve 50 is controlled to be closed.

[0051] Here, when the fuel hydrogen gas cutoff valve 44 is controlled to be open and the product hydrogen diffusion cutoff valve 50 is controlled to be closed, as shown in FIG. 4 as a modification of FIG. 3, during idling operation, the excess hydrogen (G 4c When using the fuel F, it may be directly supplied to the burner 22 as fuel without being introduced into the off-gas holder 45. In addition, supplying the fuel F to the off-gas holder 45 as in the system configuration of FIG. 3 is preferable because it averages the calories of the fuel F and results in more stable operation.

[0052] Figure 5 shows the trends in recycled hydrogen during normal operation (30-100% load), idle operation (load less than 30% while recycled hydrogen is being increased), and idle operation (load less than 30% after recycled hydrogen increase is completed / excess hydrogen is being sent out). FIG. 5 is a graph showing an increase in the amount of hydrogen from the normal case (0.05 times the amount of the raw material gas) to 4 times the amount of the raw material gas.

[0053] As shown in Figure 5, during normal operation (Figure 1), recycled hydrogen is used as hydrogenation recycled hydrogen G 4a This is the amount of hydrogen required for the hydrogenation reaction (0.05 times the amount of raw gas G1). At this time, in the operation of the PC screen 200 in Fig. 1, the "Delivery" button is operated on the panel for product hydrogen delivery 200A. In this case, the button is "OFF" on the panel for standby operation 200B.

[0054] 1 to 3, the shutoff valves 43, 44, 50 are indicated as open and as closed by the filled-in marks. During normal operation, when "delivery" is selected for product hydrogen delivery on PC screen 200 as shown in FIG. 1, product hydrogen gas delivery valve 43 is in the "open" state.

[0055] To switch from normal operation to idle operation, it is necessary to turn standby operation "ON" on the PC screen 200. This operation "stops" the delivery of product hydrogen, and in this state the product hydrogen gas delivery valve 43 is "closed" and the product hydrogen diffusion cutoff valve 50 is "open". Then, the opening of the recycled hydrogen flow rate adjustment valve 49 is gradually increased.

[0056] After it is confirmed by the recycled hydrogen flow meter 48 that the specified flow rate has been reached, the product hydrogen emission shutoff valve 50 is closed and the fuel hydrogen gas shutoff valve 44 is opened. At this point, hydrogen emission becomes zero.

[0057] In other words, during idling operation (Fig. 2), the recycled hydrogen is idling recycled hydrogen G 4b The amount of hydrogen required for the hydrogenation reaction in normal operation (FIG. 1) (0.05 times the amount of raw gas G1) is gradually increased to a specified amount (for example, 4 times in this example). At this time, in the operation of the PC screen 200 in FIG. 2, the "Stop" button is operated on the panel for product hydrogen delivery 200A. In this case, the "ON" button is displayed on the panel for standby operation 200B.

[0058] Next, during idling operation (recycled hydrogen increase completed (Figure 3)), the recycled hydrogen is used as the idling recycled hydrogen G 4b The specified amount (for example, four times the amount in this example) is maintained. At this time, in the operation of the PC screen 200 in Fig. 3, the "Stop" button is operated on the panel for product hydrogen delivery 200A. In this case, the "ON" button is displayed on the panel for standby operation 200B.

[0059] In this way, during idle operation, the off-gas G5 from the hydrogen purification device 40 is supplied to the off-gas line L as the fuel F for the burner 22 of the reformer 20. 12 Using this off-gas line L 12 Part of the refined gas G4 (off-gas introduced hydrogen G 4c ) into the surplus hydrogen introduction line L 13and uses it as fuel F for the burner 22. This makes it possible to stop the discharge of product hydrogen to the outside (air supply: none).

[0060] Figure 5 shows the relationship between the increase in recycled hydrogen between "normal operation" shown in Figure 1, "idle operation (load less than 30% while increasing recycled hydrogen); recycled hydrogen being increased" shown in Figure 2, and "idle operation (load less than 30% while increasing recycled hydrogen); recycled hydrogen increase completed / excess hydrogen sent" shown in Figure 3.

[0061] In Figure 5, the amount of hydrogen for the hydrogenation reaction during normal operation is set to 0.05 times the raw material flow rate at rated load, and there is no fluctuation in the amount of hydrogen sent out. During low-load idling operation, as shown in Figure 2, the idle recycle hydrogen G 4b As shown in Fig. 3, after the increase in the amount of recycled hydrogen is completed, the increased state is maintained until the end of idle operation, and the flow rate of the idle recycled hydrogen G is gradually increased. 4b The flow rate is constant.

[0062] As described above, according to the present invention, the amount of hydrogen produced is, for example, 800 Nm 3 When a hydrogen production plant with a capacity of 1000000 / h was operated at idle, the amount of recycled hydrogen was 7.5 times that during normal operation, and the raw material flow rate was 100 Nm3 at 30% load. 3 / h, while idling is 30-40Nm 3 This means that the load can be reduced to approximately / h.

[0063] In this way, even when the hydrogen production device is operated at a lower load (less than 30%), it is possible to realize operation without sending hydrogen out of the system as in the conventional case. That is, there is an operation in which hydrogen and water vapor are circulated in the system up to the stage before the PSA unit and the temperature of the equipment is maintained, such as "hydrogen circulation operation," which is realized as a standby operation that does not emit hydrogen. However, this operating method does not include a hydrogen production process, so the amount of hydrogen generated is zero, and in addition, returning to normal operation requires start-up processes such as reintroducing raw materials and restarting the PSA unit, which takes approximately 2 to 3 hours.

[0064] In contrast, in the present invention, while hydrogen is produced, surplus hydrogen is supplied as fuel to the burner 22 of the reformer 20. Therefore, unlike the conventional method, a part of the raw gas G1 is converted into the fuel gas G 1a In addition, because hydrogen production is not stopped as in the past but is instead kept in an idle state, start-up is also quicker. For example, when starting up a hydrogen production device from a completely stopped state, it takes about 4 to 6 hours, whereas when returning from idle operation as in the present invention, the start-up time can be shortened to about 1.5 hours. [Industrial Applicability]

[0065] INDUSTRIAL APPLICABILITY The present invention can be applied to hydrogen production apparatuses and hydrogen production methods in general, which can operate the hydrogen production apparatus at a lower load and realize operation without sending product hydrogen outside the system. [Explanation of symbols]

[0066] 10 Compressor 13 Raw material preheater 14 Desulfurizer 15 Raw material heater 22 Burner 30 Transformer 40 PSA units G1 raw gas G2 reformed gas G3 Transformed Gas G4 refined gas G5 Offgas

Claims

1. a raw material introduction line for introducing a raw material gas; a desulfurizer provided in the raw material introduction line for desulfurizing the sulfur content in the raw material gas; a reformer for reforming the desulfurized raw material gas; a transformer that transforms the reformed gas after reforming in the reformer; a hydrogen purification device that purifies the converted gas after the conversion by the converter; A hydrogen production apparatus comprising: a recycle hydrogen line for recycling a portion of the purified hydrogen gas from the hydrogen purification device to the raw material introduction line on the inlet side of the compressor, During normal operation of hydrogen production, the amount of purified hydrogen gas recycled through the recycle hydrogen line is hydrogen required for the hydrogenation reaction in the desulfurizer, and A hydrogen production apparatus characterized in that, during low-load idling operation, the amount of purified hydrogen gas recycled through the recycle hydrogen line is 4 to 10 times the amount of hydrogen used in the hydrogenation reaction in the desulfurizer.

2. The normal operation is a load operation of 30 to 100%, 2. The hydrogen production apparatus according to claim 1, wherein the idle operation is a low load operation of less than 30%.

3. 3. The hydrogen production device according to claim 1, wherein the heating temperature of the reformer is set to 600° C. or higher and 850° C. or lower during the idle operation.

4. 3. The hydrogen production apparatus according to claim 1, wherein the amount of recycled hydrogen gas for hydrogenation is gradually increased to a desired specified value during the idle operation.

5. an off-gas line is provided for supplying off-gas from the refining device as fuel for a burner of the reforming device during the idle operation; 3. The hydrogen production device according to claim 1, wherein a part of the refined gas is supplied to the off-gas line through a surplus hydrogen introduction line and used as fuel for the burner.

6. a raw material introduction line for introducing a raw material gas; a desulfurizer provided in the raw material introduction line for desulfurizing the sulfur content in the raw material gas; a reformer for reforming the desulfurized raw material gas; a transformer that transforms the reformed gas after reforming in the reformer; a hydrogen purification device that purifies the converted gas after the conversion by the converter; a recycle hydrogen line for recycling a portion of the purified hydrogen gas from the hydrogen purification device to the raw material introduction line on the inlet side of the compressor; A hydrogen production device comprising: During normal operation of hydrogen production, the amount of purified hydrogen gas recycled through the recycle hydrogen line is adjusted to supply hydrogen necessary for the hydrogenation reaction in the desulfurizer, A hydrogen production method, characterized in that, during low-load idling operation, the amount of purified hydrogen gas recycled through the recycle hydrogen line is 4 to 10 times the amount of hydrogen used in the hydrogenation reaction in the desulfurizer.

7. The normal operation is a load operation of 30 to 100%, 7. The method for producing hydrogen according to claim 6, wherein the idle operation is a low load operation of less than 30%.

8. 8. The method for producing hydrogen according to claim 6, wherein the heating temperature of the reformer is set to 600° C. or higher and 850° C. or lower during the idle operation.

9. 8. The method for producing hydrogen according to claim 6, wherein the amount of the purified hydrogen gas to be recycled is gradually increased to a desired specified value during the idle operation.

10. During the idle operation, an off-gas line is used to supply the off-gas from the refinery device as fuel for a burner of the reformer, 8. The method for producing hydrogen according to claim 6, wherein a part of the refined gas is supplied to the off-gas line through a surplus hydrogen introduction line and used as fuel for the burner.

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