Hydrogen production apparatus and operation method therefor

Abstract

To provide a hydrogen production apparatus capable of shortening a heat up time in a start up operation.SOLUTION: A hydrogen production apparatus is configured so that: an operation control part M supplies a raw material gas G and water vapor to a reformer 2 for generating a modified gas K, and supplies the modified gas K from a modification processing part AK to an adsorption tower 1 for producing a product gas H, namely executing product gas production operation. A desulfurizer 6 has: desulfurization catalyst 6B for removing a sulfur constituent in the raw material gas G; and an oxidation catalyst 6A for promoting a reaction between a hydrogen constituent and an oxygen constituent included in at least one of the modified gas K and product gas H. The apparatus further has an air supply unit AS for supplying air into the desulfurizer 6.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] The hydrogen production device uses a reforming section to reform a raw material gas, which is a hydrocarbon gas such as natural gas or naphtha, into a reformed gas with a high hydrogen content through a steam reforming process, and then uses a pressure fluctuation adsorption section to adsorb the components to be adsorbed from the reformed gas, which contains hydrogen components and components to be adsorbed other than hydrogen components, onto an adsorbent, thereby producing a product gas with a high hydrogen concentration.

[0003] A known conventional hydrogen production apparatus is described, for example, in Patent Document 1. This hydrogen production apparatus comprises a reforming processing unit including a compressor for supplying a raw material gas containing a hydrogen component, a desulfurizer for desulfurizing the raw material gas supplied by the compressor, and a reformer for steam reforming the raw material gas from the desulfurizer while the raw material gas is heated to a reforming temperature by a heating burner to produce a reformed gas with a high hydrogen component, a pressure swing adsorption unit including multiple adsorption towers that perform a pressure swing adsorption operation in which components to be adsorbed other than the hydrogen component from the reformed gas are adsorbed onto an adsorbent to produce a product gas and the components to be adsorbed are discharged as off-gas, a product gas tank for recovering the product gas, an off-gas supply path for supplying the off-gas to the heating burner as combustion fuel, and an operation control unit.

[0004] In conventional hydrogen production devices, the heat source for the temperature rise within the device during the temperature rise process at startup is mainly the combustion heat of the heating burner of the reformer, and it takes a certain amount of time for the temperature rise to be completed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2020-158357 Summary of the Invention [Problem to be solved by the invention]

[0006] To improve processing efficiency, it is desirable to shorten the time required for heating and to minimize the time required for hydrogen production to begin. In particular, it is difficult to raise the temperature of the desulfurizer, which is a bottleneck in the heating process.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydrogen production device that can shorten the temperature rise time during startup operation. [Means for solving the problem]

[0008] The hydrogen production apparatus according to the present invention is configured to include a reforming processing section including a desulfurizer that desulfurizes a raw material gas containing hydrogen components, and a reformer that steam reforms the raw material gas from the desulfurizer while the raw material gas is heated to a reforming temperature by a heating burner to produce a reformed gas having a high hydrogen component; a pressure swing adsorption unit including a plurality of adsorption towers that perform a pressure swing adsorption operation in which components to be adsorbed other than the hydrogen component from the reformed gas are adsorbed onto an adsorbent to generate a product gas and the components to be adsorbed are discharged as an off-gas; an off-gas supply passage that supplies the off-gas to the heating burner as combustion fuel; An operation control unit is provided, a hydrogen production apparatus configured such that the operation control unit executes a product gas production operation in which the raw material gas and steam are supplied to the reformer to generate the reformed gas, and the reformed gas from the reforming treatment unit is supplied to the adsorption tower to produce the product gas, the desulfurizer includes a desulfurization catalyst that removes sulfur components from the raw material gas, and an oxidation catalyst that promotes a reaction between hydrogen components contained in at least one of the reformed gas and the product gas and oxygen molecules; An air supply device is provided to supply air to the desulfurizer.

[0009] According to this configuration, the oxygen molecules in the air supplied from the air supply device react with the hydrogen components contained in at least one of the reformed gas and the product gas via the oxidation catalyst in the desulfurizer, making it easier to raise the internal temperature of the desulfurizer. This, combined with the combustion heat from the heating burner, efficiently raises the temperature of the entire reforming treatment section, shortening the temperature rise time during startup and therefore the time until hydrogen production begins.

[0010] In the hydrogen production apparatus according to the present invention, it is preferable that the desulfurizer is equipped with a thermometer, and that the operation control unit controls the air supply device to adjust the amount of air supplied so that the temperature of the desulfurizer is maintained within a predetermined temperature range.

[0011] According to this configuration, the temperature of the desulfurizer can be controlled by the operation control unit, and in addition to shortening the temperature rise time, it is possible to carry out a more efficient desulfurization process.

[0012] The method for operating a hydrogen production apparatus according to the present invention includes a reforming unit including a desulfurizer that desulfurizes a raw material gas containing hydrogen components, and a reformer that generates a reformed gas having a high hydrogen component by steam reforming the raw material gas from the desulfurizer while the raw material gas is heated to a reforming temperature by a heating burner; a pressure swing adsorption unit including a plurality of adsorption towers that perform a pressure swing adsorption operation in which components to be adsorbed other than the hydrogen component from the reformed gas are adsorbed onto an adsorbent to generate a product gas and the components to be adsorbed are discharged as an off-gas; an off-gas supply passage that supplies the off-gas to the heating burner as combustion fuel; the desulfurizer includes a desulfurization catalyst that removes sulfur components from the raw material gas, and an oxidation catalyst that promotes a reaction between hydrogen components contained in at least one of the reformed gas and the product gas and oxygen molecules; an air supply device that supplies air to the desulfurizer; a method for operating a hydrogen production apparatus configured to perform a product gas production operation in which the raw material gas and steam are supplied to the reformer to generate the reformed gas, and the reformed gas from the reforming treatment unit is supplied to the adsorption tower to produce the product gas, During startup operation, in which at least one of the reformed gas and the product gas is circulated through the desulfurizer and the reformer with the gas supply from the reforming treatment unit to the pressure fluctuation adsorption unit cut off, air is supplied to the desulfurizer to react oxygen molecules in the air with hydrogen components contained in at least one of the reformed gas and the product gas, thereby raising the temperature inside the desulfurizer.

[0013] According to this configuration, the oxygen molecules in the air supplied from the air supply device react with the hydrogen components contained in at least one of the reformed gas and the product gas via the oxidation catalyst in the desulfurizer, making it easier to raise the internal temperature of the desulfurizer. This, combined with the combustion heat from the heating burner, efficiently raises the temperature of the entire reforming treatment section, shortening the temperature rise time during startup and therefore the time until hydrogen production begins.

[0014] In the method for operating a hydrogen production apparatus according to the present invention, it is preferable that the amount of air supplied is adjusted so that the temperature inside the desulfurizer is maintained within a predetermined temperature range.

[0015] According to this configuration, it is possible to control the temperature of the desulfurizer, which not only shortens the temperature rise time but also enables more efficient desulfurization treatment. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is an overall view showing a hydrogen production device. [Figure 2] FIG. 2 is a schematic diagram showing a pressure fluctuation adsorption unit. [Figure 3] FIG. 4 is a diagram showing an operation cycle of the pressure fluctuation adsorption unit. [Figure 4] FIG. 10 is a diagram illustrating a water vapor purge process. [Figure 5] FIG. 1 illustrates a product gas purge process. [Figure 6] FIG. [Figure 7] FIG. 10 is a diagram illustrating a pressure increase process in the initial operation process. [Figure 8] FIG. 10 is a diagram showing the purity extraction process of the initial operation process. DETAILED DESCRIPTION OF THE INVENTION

[0017] [Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. (Overall configuration of hydrogen production equipment) As shown in Figure 1, the hydrogen production apparatus is provided with a reforming processing unit AK that reforms raw material gas G, which is a hydrocarbon gas such as natural gas or naphtha, into reformed gas K with a high hydrogen content, a pressure swing adsorption unit BS equipped with an adsorption tower 1 that adsorbs components to be adsorbed other than the hydrogen component from the reformed gas K from the reforming processing unit AK onto an adsorbent to produce product gas H, a product gas tank U that recovers the product gas H produced in the pressure swing adsorption unit BS, an off-gas tank T that recovers the off-gas discharged from the pressure swing adsorption unit BS, and an operation control unit M that controls the operation of the reforming processing unit AK and the pressure swing adsorption unit BS.

[0018] The raw material gas G contains methane, carbon dioxide, carbon monoxide, and nitrogen in addition to the hydrogen component, and methane, carbon dioxide, carbon monoxide, and nitrogen are adsorbed onto the adsorbent in the adsorption tower 1 as the components to be adsorbed other than hydrogen.

[0019] (Details of the modification processing section) The reforming processing section AK is equipped with a steam mixing section J that mixes steam with the raw material gas G, a reforming reaction tube 2 that serves as a reformer that reforms the raw material gas G into a reformed gas K having a high hydrogen content through a steam reforming process, and a heating burner N that heats the reforming reaction tube 2 to a reforming reaction temperature (e.g., 700°C).

[0020] An off-gas supply path 4 is provided to supply the off-gas stored in the off-gas tank T to the heating burner N, and an air supply path 5a is also provided to supply combustion air from an air supply unit 5 such as a blower to the heating burner N. An auxiliary fuel gas path 3 is also provided to supply the raw material gas G as fuel gas to the heating burner N. The off-gas supply path 4 is provided with an off-gas on-off valve 4A that opens and closes the off-gas supply path 4, and the auxiliary fuel gas path 3 is provided with a fuel gas valve 3A that opens and closes the auxiliary fuel gas path 3.

[0021] A compressor 7 is provided that sends the raw material gas G introduced through a gas inlet line 7A to the desulfurizer 6 through a delivery line 7D, and a mixing section transfer line 9 is provided that transfers the raw material gas G desulfurized in the desulfurizer 6 to a water mixing section 8. An air supply device AS that supplies air to the desulfurizer 6 is provided on the gas inlet line 7A upstream of the compressor 7 and downstream of the connection point with the recycle gas line 19. Although not shown, the air supply device AS is equipped with an air flow rate adjustment valve.

[0022] The desulfurizer 6 includes a desulfurization catalyst 6B that removes sulfur components from the raw material gas G, and an oxidation catalyst 6A that promotes a reaction between hydrogen components contained in at least one of the reformed gas K and the product gas H and oxygen molecules. The desulfurizer 6 also preferably includes a thermometer TM that can measure its internal temperature, and more preferably the thermometers TM are provided in multiple locations (e.g., three or four locations).

[0023] The desulfurization catalyst 6B removes sulfur content from the raw material gas G by hydrodesulfurization, and converts sulfur compounds contained in the raw material gas G into hydrocarbon compounds and hydrogen sulfide by reacting them with hydrogen.

[0024] The oxidation catalyst 6A, which promotes the reaction between the hydrogen component contained in at least one of the reformed gas K and the product gas H and oxygen molecules, converts oxygen and hydrogen into water through an exothermic reaction. For example, a known platinum-based catalyst or palladium-carbon-based catalyst can be used as such an oxidation catalyst 6A.

[0025] The amount of the oxidation catalyst 6A to be used is calculated, for example, based on the following formula. Oxidation catalyst weight (g) = feed gas (approximately 0.4 times the amount of hydrogen produced) x oxygen content (concentration) ÷ SV (space velocity) x density Assuming that the source gas G contains 1% oxygen, 300 Nm 3 When producing hydrogen at 1000kJ / h, the flow rate of the raw gas G is approximately 130 Nm 3 / h, so the oxygen is 1.3Nm 3 The space velocity (SV) of the oxidation catalyst is approximately 10,000 / h, so the oxidation catalyst has a flow rate of 1.3 / 10,000m 3 =130cm 3 If a palladium-carbon catalyst is to be added, the density is 0.4 g / cm 3 Therefore, approximately 50 g of oxidation catalyst is required.

[0026] The water mixer 8 is configured to mix the desulfurized raw material gas G with water (pure water) supplied from the water supply unit 10. A raw material gas supply valve Ga is provided to turn on and off the supply of the raw material gas G to the gas introduction line 7A.

[0027] An evaporation transport line 12 is provided to transport the raw material gas G mixed with water in the water mixing section 8 toward the evaporation heat exchange section 11, and the water mixed with the raw material gas G is heated in the evaporation heat exchange section 11 to become water vapor. Incidentally, in this embodiment, the water vapor mixing section J is configured with the water mixing section 8 and the evaporation heat exchange section 11 as main components.

[0028] The raw material gas G heated in the evaporation heat exchange section 11 to a state containing water vapor (a state mixed with water vapor) is transported to the reforming reaction tube 2 by the reaction tube transport line 13 and reformed into a reformed gas K having a large hydrogen component by a steam reforming process. That is, the reforming reaction tube 2 is filled with a reforming catalyst, and is heated to a reforming reaction temperature (e.g., 700°C) by the heating burner N as described above, whereby the raw material gas G is reformed into a reformed gas K having a large hydrogen component by a steam reforming process.

[0029] Incidentally, in this embodiment, the combustion gas of the heating burner N is configured to heat the reforming reaction tube 2, then flow toward the evaporation heat exchange section 11, and after heating the evaporation heat exchange section 11, be discharged through the exhaust gas path 14.

[0030] A transformer transfer line 16 is provided to transfer the reformed gas K from the reforming reaction tubes 2 to a CO transformer 15, and carbon monoxide contained in the reformed gas K is transformed into carbon dioxide in the CO transformer 15. The reformed gas K transformed in the CO transformer 15 is then supplied to the pressure swing adsorption unit BS through a reformed gas supply line 17. A water separator 18 is provided in the reformed gas supply line 17 to remove excess moisture from the reformed gas K, and a supply on / off valve 17A is provided in the reformed gas supply line 17 downstream of the water separator 18.

[0031] Furthermore, in order to supply the reformed gas K from which water has been removed in the water separator 18 as hydrogen gas for desulfurization treatment in the desulfurizer 6, a recycle gas line 19 is provided that guides the reformed gas K flowing through the reformed gas supply line 17 to a location upstream of the compressor 7, i.e., the gas introduction line 7A. A line opening / closing valve 19A is provided in the recycle gas line 19. A communication line L that connects the product gas tank U to a location along the recycle gas line 19 is also provided, and a communication opening / closing valve La that opens and closes the communication line L and a communication resistance adjustment valve Lb that adjusts the flow path resistance (opening degree) of the communication line L are provided. The communication resistance adjustment valve Lb is configured using, for example, a needle valve.

[0032] (Details of pressure fluctuation adsorption section) The pressure swing adsorption unit BS of this embodiment includes a first adsorption tower A, a second adsorption tower B, and a third adsorption tower C as adsorption towers 1. As shown in Fig. 2, the lower portion of each of the three adsorption towers 1 is connected to the reformed gas supply line 17 via a first supply branch line 21a equipped with a first supply valve 20a, a second supply branch line 21b equipped with a second supply valve 20b, and a third supply branch line 21c equipped with a third supply valve 20c.

[0033] Each adsorption tower 1 is filled with an adsorbent that adsorbs components to be adsorbed other than the hydrogen component from the reformed gas K. The components to be adsorbed other than the hydrogen component include carbon dioxide, carbon monoxide, methane, nitrogen, etc., and carbon monoxide and methane are combustible components.

[0034] In addition, the upper portions of the three adsorption towers 1 are connected to a product gas discharge line 22 connected to a product gas tank U via a first discharge branch line 22a equipped with a first discharge valve 23a, a second discharge branch line 22b equipped with a second discharge valve 23b, and a third discharge branch line 22c equipped with a third discharge valve 23c.

[0035] 1, a product gas discharge line Q branches off from the product gas discharge line 22, and a product gas discharge valve Qa is provided for opening and closing the product gas discharge line Q. Furthermore, a product gas valve 22A for opening and closing the product gas discharge line 22 is provided downstream of the branch point of the product gas discharge line Q in the product gas discharge line 22. Note that the product gas discharge line Q, product gas release valve Qa, and product gas valve 22A are not shown in FIG.

[0036] 2, the upper portion of each of the three adsorption towers 1 is connected to the pressure equalization line 24 via a first pressure equalization branch line 24a equipped with a first pressure equalization valve 25a, a second pressure equalization branch line 24b equipped with a second pressure equalization valve 25b, and a third pressure equalization branch line 24c equipped with a third pressure equalization valve 25c. A cleaning line 26 is provided to allow the product gas H flowing through the product gas discharge line 22 to flow into the pressure equalization line 24, and a cleaning valve 27 is disposed in the cleaning line 26.

[0037] Furthermore, as shown in FIG. 2, the lower portion of each of the three adsorption towers 1 is connected to an off-gas discharge line 28 via a first off-gas branch path 28a equipped with a first off-gas valve 29a, a second off-gas branch path 28b equipped with a second off-gas valve 29b, and a third off-gas branch path 28c equipped with a third off-gas valve 29c, and the off-gas discharge line 28 is connected to an off-gas tank T.

[0038] The pressure swing adsorption unit BS is configured to generate product gas H containing highly pure hydrogen gas components from the reformed gas K by repeatedly performing an operation cycle consisting of an adsorption process, a pressure equalization discharge process, a depressurization process, a cleaning process as a regeneration process, a pressure equalization receiving process, and a pressure increase process in each of the three adsorption towers 1, with different operation phases, as shown in Figure 3, under operation control by the operation control unit M.

[0039] In other words, the operating cycle is configured to repeatedly execute a first unit cycle in which the first adsorption tower A performs the adsorption process, a second unit cycle in which the second adsorption tower B performs the adsorption process, and a third unit cycle in which the third adsorption tower C performs the adsorption process.

[0040] The adsorption step is a step in which the reformed gas K is supplied to the adsorption tower 1 to produce the product gas H.

[0041] The pressure equalization discharge step is a step of discharging the internal gas of the adsorption tower 1 after the adsorption step as a pressure equalization gas.

[0042] The depressurization step is a step of discharging the internal gas of the adsorption tower 1 after the pressure equalization discharge step into the off-gas discharge line 28.

[0043] The cleaning process is a process in which product gas H is flowed through the adsorption tower 1 after the depressurization process, thereby regenerating the adsorbent to a state in which the components to be adsorbed have been desorbed, and the product gas H that has flowed through the adsorption tower 1 is discharged to the off-gas discharge line 28 as cleaning gas.

[0044] The pressure equalization receiving step is a step of receiving the pressure equalization gas discharged in the pressure equalization discharging step into the adsorption tower 1 that has completed the cleaning step.

[0045] The pressurization step is a step of supplying the product gas H to the adsorption tower 1 after the pressure equalization receiving step to increase the pressure inside the adsorption tower 1.

[0046] Incidentally, the off-gas discharged to the off-gas discharge line 28 in the decompression step and the cleaning step is recovered in the off-gas tank T, and then supplied to the heating burner N of the reforming treatment unit AK through the off-gas supply path 4. The off-gas contains carbon monoxide, methane, and hydrogen as combustible components.

[0047] As described above, the pressure swing adsorption unit BS performs a pressure swing adsorption operation using multiple (three) adsorption towers 1 to adsorb components to be adsorbed other than hydrogen components from the reformed gas K onto the adsorbent to generate product gas H and discharge the components to be adsorbed as off-gas. The pressure swing adsorption operation is configured to repeatedly perform an operation cycle in each of the multiple adsorption towers 1 with the operating phases of the multiple adsorption towers 1 being different from each other, the operation cycle including an adsorption step of supplying the reformed gas K to the adsorption towers 1 to generate product gas H, a depressurization step of discharging the internal gas of the adsorption towers 1, a cleaning step as a regeneration step of regenerating the adsorbent in the adsorption towers 1, and a pressurization step of supplying product gas H into the adsorption towers 1.

[0048] (Overview of operation control) The operation control unit M executes a product gas production operation in which the raw material gas G and steam are supplied to the reforming reaction tube 2 to generate the reformed gas K, and the reformed gas K from the reforming treatment unit AK is supplied to the adsorption tower 1 to produce the product gas. In this product gas production operation, the reforming reaction tube 2 is heated by the heating burner N, and the pressure swing adsorption unit BS performs a pressure swing adsorption operation.

[0049] When the operation control unit M stops the product gas production operation, it performs a purge operation in which a water vapor purge process and a product gas purge process are performed in sequence. When the operation control unit M starts the product gas production operation, it performs a startup operation process and an initial operation process, and then starts the product gas production operation.

[0050] Next, the steam purging process, product gas purging process, startup operation, and initial operation process will be described with reference to Figures 4 to 8. In Figures 4 to 8, flow paths through which gas flows are indicated by thick lines, and flow paths through which gas does not flow are indicated by thin lines. Therefore, since it is clear that the valves related to the flow paths through which gas flows are open and the valves related to the flow paths through which gas does not flow are closed, only the necessary parts of the valve opening and closing control will be described.

[0051] (Details of steam barge processing) 4, the steam purging process is a process in which, while the heating burner N continues to heat the reforming reaction tubes 2 and steam continues to be supplied to the reforming reaction tubes 2, a product gas H from a product gas tank U is supplied to the reforming reaction tubes 2 by a compressor 7 in place of the raw material gas G, and reformed gas K from a reforming treatment unit AK is supplied to a plurality of adsorption towers 1 performing pressure swing adsorption operation. This steam purging process continues for as long as the pressure swing adsorption unit BS performs at least one operation cycle including a first unit cycle, a second unit cycle, and a third unit cycle.

[0052] To explain further, when the product gas production operation is stopped and steam purging processing is performed, combustion in the heating burner N continues, the supply of water (pure water) from the water supply unit 10 continues, the supply of steam from the steam mixing unit J continues, and the pressure swing adsorption operation of the pressure swing adsorption unit BS continues. Incidentally, off-gas is supplied to the heating burner N as fuel gas, but if the amount of off-gas is insufficient, the fuel gas valve 3A is opened to supply raw material gas G as fuel gas.

[0053] Then, with the raw material gas supply valve Ga closed to stop the supply of raw material gas G, the communication on-off valve La is opened to allow the product gas from the product gas tank U to flow into the gas introduction line 7A through the communication line L and part of the recycle gas line 19. Incidentally, the pressure of the product gas H flowing through the communication line L is reduced due to the resistance of the communication resistance adjustment valve Lb, so that the pressure on the inlet side of the compressor 7 becomes, for example, about 0.25 MPaG, and the pressure on the outlet side of the compressor 7 becomes, for example, about 0.75 MPaG.

[0054] Therefore, in the steam purging process, the raw material gas G remaining in the desulfurizer 6, the reforming reaction tubes 2, etc. is subjected to steam reforming to generate the reformed gas K, and the product gas H containing the generated reformed gas K is supplied to the pressure swing adsorption section BS, as in the product gas production operation, and the product gas H is generated while performing pressure swing adsorption operation in the multiple adsorption towers 1. Note that Fig. 4 shows a state in which the first adsorption tower A performs the adsorption step and the third adsorption tower C performs the depressurization step.

[0055] (Product gas purge process details) 5, the product gas purging process is a process in which, while the supply of steam is stopped and heating of the reforming reaction tubes 2 by the heating burner N is continued, the product gas H from the product gas tank U is supplied to the reforming reaction tubes 2 by the compressor 7, and the product gas H from the reforming treatment unit AK is supplied to the adsorption tower 1. This product gas purging process continues for the time period during which the pressure swing adsorption unit BS performs an operation cycle including a first unit cycle, a second unit cycle, and a third unit cycle at least once.

[0056] To explain further, when the steam purging process is stopped and the product gas purging process is performed, the combustion of the heating burner N continues, the supply of water (pure water) from the water supply unit 10 is stopped, the supply of steam from the steam mixing unit J is stopped, and the pressure swing adsorption operation of the pressure swing adsorption unit BS continues. Incidentally, the fuel gas valve 3A is opened and the raw material gas supply valve Ga is opened to supply raw material gas G as fuel gas to the heating burner N.

[0057] Then, following the water vapor purging process, the raw material gas supply valve Ga is closed to stop the supply of raw material gas G, and the communication on-off valve La is opened to allow the product gas from the product gas tank U to flow into the gas introduction line 7A through the communication line L and part of the recycle gas line 19. Incidentally, the pressure of the product gas H flowing through the communication line L is reduced due to the resistance of the communication resistance adjustment valve Lb, so that the pressure on the inlet side of the compressor 7 becomes, for example, about 0.25 MPaG, and the pressure on the outlet side of the compressor 7 becomes, for example, about 0.75 MPaG.

[0058] Therefore, in the product gas purging process, the product gas H is caused to flow through the desulfurizer 6, the reforming reaction tube 2, the CO converter 15, etc., and the product gas H from the reforming process unit AK is supplied to the pressure swing adsorption unit BS, as in the product gas production operation, and the product gas H is produced while performing pressure swing adsorption operation in the multiple adsorption towers 1. Note that Fig. 5 shows a state in which the first adsorption tower A performs the adsorption step, and the third adsorption tower C performs the depressurization step.

[0059] By performing the product gas purge process, the product gas H is filled into the reforming process unit AK, and the reforming process unit AK is maintained at a high temperature similar to the state in which the steam reforming process is performed.Furthermore, by performing pressure swing adsorption operation on the product gas H, the adsorbent in the multiple adsorption towers 1 of the pressure swing adsorption unit BS is regenerated to a desorption state in which the adsorbent does not adsorb the components to be adsorbed.

[0060] (Start-up operation details) When starting operation from a stopped state in which the supply of raw material gas G has been stopped and the combustion of the reforming burner B has been stopped, the operation control unit M will perform startup operation, and then perform steady-state operation in which the supply of raw material gas G to the compressor 7 is started and the reformed gas K is produced.

[0061] During startup operation, the supply of raw material gas G to the compressor 7 is stopped and the heating burner N is burning, and the product gas H is circulated through the desulfurizer 6, reforming reaction tube 2, CO converter 15, etc. to raise the temperature to a set target state. The set target state is, for example, a state in which the inlet temperature of the reforming reaction tube 2 is 200°C or higher, the temperature at the bottom of the desulfurizer 6 is 210°C or higher, and the temperature at the bottom of the CO converter 15 is 170°C or higher.

[0062] 6, the startup operation is an operation in which the reformed gas supply line 17 serving as the gas supply line from the reforming process unit AK to the pressure swing adsorption unit BS is shut off, the adsorbent in the adsorption tower 1 of the pressure swing adsorption unit BS is maintained in a state in which the components to be adsorbed have been desorbed, and the supply of steam to the reforming process unit AK is stopped while the heating of the reforming reaction tube 2 by the heating burner N is continued, and the product gas H filled in the reforming process unit AK is circulated by returning it to the compressor 7 via the recycle gas line 19 serving as a return line when it is discharged from the reforming process unit AK. Also, during the startup operation, the operation control unit M activates the air supply device AS to supply air to the desulfurizer 6.

[0063] To explain further, when the product gas purge process is stopped and startup operation is performed, combustion in the heating burner N continues, the supply of water (pure water) from the water supply unit 10 is stopped, the supply of steam from the steam mixing unit J is stopped, and the supply interrupter valve 17A of the reformed gas supply line 17 is closed to block communication between the reformed gas supply line 17 and the three adsorption towers 1. Incidentally, the fuel gas valve 3A is opened and the raw material gas supply valve Ga is opened to supply raw material gas G as fuel gas to the heating burner N.

[0064] Then, by blocking the communication between the reformed gas supply line 17 and the three adsorption towers 1, the product gas H filled in the reforming process unit AK is circulated through the recycle gas line 19 and returned to the compressor 7. In this circulation state, the product gas H filled in the reforming process unit AK is circulated with less flow path resistance than in the steam purge process or the product gas purge process, and therefore the pressure on the outlet side of the compressor 7 becomes lower than 0.75 MPaG.

[0065] Furthermore, the first supply valve 20a, the second supply valve 20b, and the third supply valve 20c in the pressure swing adsorption unit BS are closed to stop the pressure swing adsorption operation of the pressure swing adsorption unit BS. Also, the other valves in the pressure swing adsorption unit BS, namely, the first discharge valve 23a, the second discharge valve 23b, the third discharge valve 23c, the first equalizing valve 25a, the second equalizing valve 25b, the third equalizing valve 25c, the first off-gas valve 29a, the second off-gas valve 29b, and the third off-gas valve 29c, are all closed, so that the adsorbent in the adsorption tower 1 of the pressure swing adsorption unit BS is maintained in a state in which the components to be adsorbed have been desorbed.

[0066] Therefore, during startup operation, the product gas H filled in the reforming process unit AK is circulated through the desulfurizer 6, reforming reaction tube 2, CO converter 15, etc. At this time, in the desulfurizer 6, oxygen molecules in the air supplied from the air supply unit AS react with the hydrogen components contained in the product gas H via an oxidation catalyst, making it easier to raise the internal temperature of the desulfurizer 6. Then, together with the combustion heat from the heating burner N, the entire reforming process unit AK is efficiently heated, shortening the temperature rise time and therefore the time until hydrogen production starts. Note that, with respect to the pressure swing adsorption unit BS, the adsorbent in the adsorption tower 1 is maintained in a state in which the components to be adsorbed have been desorbed.

[0067] Furthermore, if the desulfurizer 6 is equipped with a thermometer TM, the operation control unit M is configured to control the air supply device AS to adjust the amount of air supplied so that the temperature inside the desulfurizer 6 is maintained within a predetermined temperature range (for example, 300°C to 350°C).

[0068] (Details of initial operation process) The initial operation process is a process performed when the startup operation is stopped and the product gas production operation is started, and immediately after the start, raw material gas G and steam are supplied to the reforming reaction tube 2 to generate reformed gas K, and the reformed gas K from the reforming treatment unit AK is supplied to the adsorption tower 1 to produce product gas H. If the concentration of hydrogen components in the produced product gas H is below a set value, the product gas H is discarded. Then, by performing the initial operation process, if the concentration of hydrogen components in the produced product gas H becomes equal to or greater than the set value, the system will transition to product gas production operation in which product gas H is recovered in the product gas tank U.

[0069] In this embodiment, as an initial operation process, a pressure increase process is first performed to increase the internal pressure of the reforming processing unit AK and the adsorption tower 1 that initially supplies the reformed gas K in the pressure swing adsorption unit BS, and then the product gas H is produced while performing pressure swing operation in the pressure swing adsorption unit BS, and when the concentration of the hydrogen component in the produced product gas H is less than a set value, a purity reduction process is performed to discard the product gas H.

[0070] To explain further, when the startup operation is stopped and the pressure increase process is performed, as shown in Fig. 7, the combustion of the heating burner N continues, the supply of water (pure water) from the water supply unit 10 starts, and the supply of steam from the steam mixing unit J starts. Also, the supply intermittent valve 17A of the reformed gas supply line 17 is opened. Incidentally, the fuel gas valve 3A is opened to supply the heating burner N with the raw material gas G as the fuel gas.

[0071] Then, although the pressure swing adsorption operation of the pressure swing adsorption unit BS is stopped, the first supply valve 20a in the adsorption tower 1 that initially supplies the reformed gas K to the pressure swing adsorption unit BS, for example, the first adsorption tower A, is opened and the first discharge valve 23a is closed. Also, the recycle gas line 19 is closed by the line on-off valve 19A. Incidentally, instead of closing the recycle gas line 19, the flow resistance of the recycle gas line 19 may be increased, for example, by half-opening the line on-off valve 19A.

[0072] Therefore, reformed gas K is produced in the reforming processing unit AK, and the reformed gas K is supplied to the adsorption tower 1 that first supplies the reformed gas K in the pressure fluctuation adsorption unit BS, for example, the first adsorption tower A. Furthermore, since the first discharge valve 23a of the first adsorption tower A is closed, the internal pressure of the reforming processing unit AK and the internal pressure of the first adsorption tower A that is first supplied with the reformed gas K are increased to a set pressure (for example, 0.75 MPaG).

[0073] When the internal pressure of the reforming unit AK and the internal pressure of the first adsorption tower A to which the reformed gas K is initially supplied are increased to the set pressure, the purification process is carried out as shown in FIG. To explain further, when the purification process is performed, the pressure swing adsorption operation of the pressure swing adsorption unit BS is started with the product gas valve 22A closed and the product gas release valve Qa open. Also, the line on-off valve 19A is opened to open the recycle gas line 19.

[0074] Therefore, when reformed gas K is supplied from the reforming processing unit AK to the pressure swing adsorption unit BS, product gas H is produced by pressure swing adsorption operation, and when the concentration of the hydrogen component in the produced product gas H is less than a set value, the product gas H is discarded through the product gas release line Q.

[0075] When the concentration of the hydrogen component in the produced product gas H reaches or exceeds a set value, the product gas release valve Qa is closed and the product gas valve 22A is opened, thereby transitioning to product gas production operation in which the product gas is recovered into the product gas tank U.

[0076] In this embodiment, during the initial operation process, the supply amount of raw material gas G supplied by compressor 7 is set to 40% of the maximum supply amount during product gas production operation, and the time required for performing an operation cycle for the supply amount of raw material gas G supplied by compressor 7 is set to be, for example, approximately 20% shorter than the time required for product gas production operation.

[0077] Although not shown, a pressure sensor is provided to detect the internal pressure of the adsorption tower 1, and is configured to detect whether the internal pressure of the adsorption tower 1 has been increased to a set pressure (e.g., 0.75 MPaG) during the pressure increase process. Also, a concentration sensor is provided in the product gas discharge line 22 upstream of the branch point of the product gas release line Q to detect the concentration of the hydrogen component in the product gas H, and is configured to detect whether the concentration of the hydrogen component in the product gas H is equal to or higher than a set value during the purification process.

[0078] Furthermore, a temperature sensor for detecting the temperature of the reforming catalyst is provided inside the reforming reaction tube 2, and the combustion amount of the heating burner N is controlled so that the detected temperature becomes the reforming reaction temperature (for example, 700°C). In other words, the combustion amount of the heating burner N is controlled by controlling the supply amount of off gas as fuel gas supplied through the off gas supply path 4 and the supply amount of raw material gas G as fuel gas supplied through the auxiliary fuel gas path 3, and the amount of air supplied through the air supply path 5a is adjusted in accordance with the supply amount of fuel gas.

[0079] [Another embodiment] Next, other embodiments will be listed. (1) In the above embodiment, the product gas H is circulated during startup operation, but the reformed gas K may be circulated instead.

[0080] (2) In the above embodiment, the pressure swing adsorption unit BS is exemplified as having three adsorption towers 1, but the present invention is also applicable to configurations in which the pressure swing adsorption unit BS is configured to have two or four or more adsorption towers 1.

[0081] (3) In the above embodiment, the water vapor mixing section J is configured to mix water with the raw material gas G and then evaporate the mixed water in the evaporation heat exchange section 11. However, the water vapor mixing section J may also be configured to mix pre-generated water vapor with the raw material gas G.

[0082] (4) In the above embodiment, the initial operation process is performed by increasing the pressure only using the reformed gas K from the reforming processing unit AK. However, the specific configuration of the initial operation process can be modified in various ways, for example, by increasing the pressure while supplying the product gas H to the adsorption tower 1 to which the reformed gas K is initially supplied.

[0083] (5) In the above embodiment, the supply on / off valve 17A is provided in the reformed gas supply line 17. However, the supply on / off valve 17A may be omitted by interrupting the communication between the reformed gas supply line 17 and the adsorption tower 1 by closing the first supply valve 20a, the second supply valve 20b, and the third supply valve 20c in the pressure fluctuation adsorption section BS.

[0084] The configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, as long as no contradiction arises. Furthermore, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited to these, and can be modified as appropriate within the scope that does not deviate from the purpose of the present invention. [Explanation of symbols]

[0085] 1:Adsorption tower 4: Off-gas supply line 6: Desulfurizer 7: Compressor AK: Modification processing section AS: Air supply device BS: Pressure fluctuation adsorption section G: Raw material gas H: Product gas K: Reformed gas M: Operation control unit N: Heating burner TM: Thermometer U: Product gas tank

Claims

1. a reforming processing section including a desulfurizer that desulfurizes a raw material gas containing a hydrogen component, and a reformer that steam reforms the raw material gas from the desulfurizer while being heated to a reforming temperature by a heating burner to produce a reformed gas having a large hydrogen component; a pressure swing adsorption unit including a plurality of adsorption towers that perform a pressure swing adsorption operation in which components to be adsorbed other than the hydrogen component from the reformed gas are adsorbed onto an adsorbent to generate a product gas and the components to be adsorbed are discharged as an off-gas; an off-gas supply passage that supplies the off-gas to the heating burner as combustion fuel; An operation control unit is provided, a hydrogen production apparatus configured such that the operation control unit executes a product gas production operation in which the raw material gas and steam are supplied to the reformer to generate the reformed gas, and the reformed gas from the reforming treatment unit is supplied to the adsorption tower to produce the product gas, the desulfurizer includes a desulfurization catalyst that removes sulfur components from the raw material gas, and an oxidation catalyst that promotes a reaction between hydrogen components contained in at least one of the reformed gas and the product gas and oxygen molecules; The hydrogen production apparatus is provided with an air supply device that supplies air to the desulfurizer.

2. 2. The hydrogen production apparatus according to claim 1, wherein the desulfurizer is equipped with a thermometer, and the operation control unit controls the air supply device to adjust the amount of air supplied so that the temperature of the desulfurizer is maintained within a predetermined temperature range.

3. a reforming processing section including a desulfurizer that desulfurizes a raw material gas containing a hydrogen component, and a reformer that steam reforms the raw material gas from the desulfurizer while being heated to a reforming temperature by a heating burner to produce a reformed gas having a large hydrogen component; a pressure swing adsorption unit including a plurality of adsorption towers that perform a pressure swing adsorption operation in which components to be adsorbed other than the hydrogen component from the reformed gas are adsorbed onto an adsorbent to generate a product gas and the components to be adsorbed are discharged as an off-gas; an off-gas supply passage that supplies the off-gas to the heating burner as combustion fuel; the desulfurizer includes a desulfurization catalyst that removes sulfur components from the raw material gas, and an oxidation catalyst that promotes a reaction between hydrogen components contained in at least one of the reformed gas and the product gas and oxygen molecules; an air supply device that supplies air to the desulfurizer; a method for operating a hydrogen production apparatus configured to perform a product gas production operation in which the raw material gas and steam are supplied to the reformer to generate the reformed gas, and the reformed gas from the reforming treatment unit is supplied to the adsorption tower to produce the product gas, A method for operating a hydrogen production apparatus, in which at least one of the reformed gas and the product gas is circulated through the desulfurizer and the reformer while the gas supply from the reforming treatment unit to the pressure fluctuation adsorption unit is shut off, and during startup operation, air is supplied to the desulfurizer to raise the temperature inside the desulfurizer by reacting oxygen molecules in the air with hydrogen components contained in at least one of the reformed gas and the product gas.

4. 4. The method for operating a hydrogen production apparatus according to claim 3, wherein the amount of air supplied is adjusted so that the temperature inside the desulfurizer is maintained within a predetermined temperature range.

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