Hydrogen production equipment

Abstract

To provide a hydrogen production apparatus capable of appropriately recovering carbon dioxide while achieving simplification of an entire configuration.SOLUTION: A hydrogen production apparatus includes: an absorption liquid supply section 31 for supplying downward an absorption liquid absorbing carbon dioxide inside a liquid separator 18; a partition section A for receiving and recovering the absorption liquid in a state of forming an absorption liquid storage section 25 in a place above a liquid content storage part 18a in which liquid content in a bottom of the liquid separator 18 is stored; a modified gas discharge section B for making modified gas supplied to a lower side of the partition section A flow to a place above the absorption liquid storage section 25 to discharge; a separation recovery section Q for separating carbon dioxide from the absorption liquid absorbing carbon dioxide to recover; an absorption liquid supply path La for supplying the absorption liquid absorbing carbon dioxide and stored in the absorption liquid storage section 25 to the separation recovery section Q; and an absorption liquid return path Lb for returning the absorption liquid from which carbon dioxide is separated from the separation recovery section Q to the absorption liquid supply section 31.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a hydrogen production apparatus provided with: a reforming processing section including a raw material gas supply unit that supplies a raw material gas containing a hydrogen component and carbon dioxide, and a reformer that generates reformed gas with high hydrogen content by subjecting the raw material gas to steam reforming while the raw material gas is heated to a reforming temperature by a heating burner; a cooling section that cools the reformed gas from the reforming processing section; a liquid separator that separates liquid components from the reformed gas cooled in the cooling section; and a pressure swing adsorption section provided with a plurality of adsorption towers that perform a pressure swing adsorption operation, where the operation generates product gas by adsorbing components to be adsorbed other than the hydrogen component onto an adsorbent from the reformed gas from which liquid components have been separated by the liquid separator, and discharges the components to be adsorbed as off-gas.

Background Art

[0002] Such a hydrogen production apparatus produces product gas with high hydrogen concentration as follows: a reforming processing section reforms a raw material gas containing a hydrogen component and carbon dioxide into reformed gas with high hydrogen content through steam reforming; a cooling section cools the reformed gas from the reforming processing section; a liquid separator separates liquid components from the cooled reformed gas to obtain reformed gas with low liquid content; and a pressure swing adsorption section adsorbs components to be adsorbed other than the hydrogen component onto an adsorbent from the reformed gas (see, for example, Patent Document 1).

[0003] Another conventional example of such a hydrogen production apparatus involves a reforming section that reforms a raw material gas containing hydrogen and carbon dioxide into a reformed gas with a high hydrogen content by steam reforming, and an absorption section that absorbs carbon dioxide contained in the reformed gas from the reforming section into an absorbent liquid, thereby producing a product gas with a high hydrogen concentration by adsorbing components other than hydrogen onto an adsorbent from the reformed gas after the carbon dioxide has been absorbed into the absorbent liquid by the pressure fluctuation adsorption section. Furthermore, a separation and recovery section is provided to separate and recover carbon dioxide from the absorbent liquid that has absorbed the carbon dioxide, and the absorbent liquid is circulated between the absorption section and the separation and recovery section to recover carbon dioxide in the separation and recovery section (see, for example, Patent Document 2).

[0004] In other words, Patent Document 2 describes a method for recovering carbon dioxide from the reformed gas before it is supplied to the pressure fluctuation adsorption unit. Incidentally, the recovered carbon dioxide can be supplied as a raw material to another processing facility (for example, a liquefied carbon dioxide production facility), thereby making effective use of the carbon dioxide contained in the off-gas. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-155242 [Patent Document 2] Japanese Patent Publication No. 2012-176879 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] In the hydrogen production apparatus described in Patent Document 2, the absorption unit absorbs carbon dioxide contained in the reformed gas from the reforming unit into the absorbent liquid without separating the liquid component contained in the reformed gas from the reforming unit. As a result, the liquid component contained in the reformed gas dilutes the absorbent liquid, reducing the amount of carbon dioxide absorbed by the absorbent liquid, which has the disadvantage of making it impossible to properly recover carbon dioxide.

[0007] To resolve this inconvenience, it is conceivable to provide an absorption section between the liquid separator and the pressure fluctuation adsorption section in the hydrogen production apparatus described in Patent Document 1. However, in this case, since an absorption section is provided in addition to the liquid separator, the overall configuration becomes complicated, which is an inconvenience.

[0008] This invention has been made in view of the above circumstances, and its purpose is to provide a hydrogen production apparatus that can appropriately recover carbon dioxide while simplifying the overall configuration. [Means for solving the problem]

[0009] The hydrogen production apparatus according to the present invention comprises a raw material gas supply unit that supplies a raw material gas containing hydrogen and carbon dioxide, and a reforming unit equipped with a reformer that generates a reformed gas with a high hydrogen content by steam reforming the raw material gas while it is heated to a reforming temperature by a heating burner. A cooling unit for cooling the reformed gas from the reforming section, A liquid separator for separating the liquid component from the reformed gas cooled in the cooling unit, The system is provided with a pressure fluctuation adsorption unit comprising multiple adsorption towers that perform pressure fluctuation adsorption operation, which involves adsorbing components other than the hydrogen component onto an adsorbent from the reformed gas separated by the liquid separator to generate a product gas and discharging the adsorbed components as an off-gas, and its characteristic configuration is as follows: An absorbent liquid supply unit that supplies the absorbent liquid that absorbs carbon dioxide downwards inside the liquid separator, A partition is provided above the liquid storage section at the bottom of the liquid separator where the liquid is stored, in which an absorbent liquid storage section is formed, to receive and collect the absorbent liquid. A modified gas discharge section that causes the modified gas supplied to the lower side of the partition to flow to the upper part of the absorbent liquid storage section and discharge it, A separation and recovery unit for separating and recovering the carbon dioxide from the absorbent liquid that has absorbed the carbon dioxide, An absorbent liquid supply path supplies the absorbent liquid, which has absorbed carbon dioxide and is stored in the absorbent liquid storage section, to the separation and recovery section. The device is equipped with an absorbent liquid return path that returns the absorbent liquid from which the carbon dioxide has been separated from the separation and recovery unit back to the absorbent liquid supply unit.

[0010] In other words, when the reformed gas from the reforming section flows into the liquid separator after being cooled in the cooling section, the liquid component contained in the reformed gas is separated into the liquid storage section at the bottom of the liquid separator, and the reformed gas, from which the liquid component has been separated, flows upward. The reformed gas flowing upward is discharged by the reformed gas discharge section to a location above the absorbent liquid storage section of the absorbent liquid that has been received and recovered in the partition section. Then, the reformed gas discharged above the absorbent liquid storage section comes into contact with the absorbent liquid supplied from the absorbent liquid supply section, and the carbon dioxide contained in the reformed gas is absorbed by the absorbent liquid supplied from the absorbent liquid supply section. The absorbent liquid that has absorbed the carbon dioxide is then received and collected at the partition section and stored in the absorbent liquid storage section.

[0011] The absorbent liquid that has absorbed carbon dioxide stored in the absorbent liquid storage section is supplied to the separation and recovery section through the absorbent liquid supply path. In the separation and recovery section, the carbon dioxide absorbed by the absorbent liquid is separated and recovered, and the absorbent liquid from which the carbon dioxide has been separated is returned from the separation and recovery section to the absorbent liquid supply section through the absorbent liquid return path.

[0012] In this way, the liquid component is separated from the reformed gas inside the liquid separator, and the carbon dioxide contained in the reformed gas from which the liquid component has been separated can be absorbed into the absorbent liquid. In the separation and recovery section, carbon dioxide can be separated and recovered from the absorbent liquid that has absorbed the carbon dioxide.

[0013] Therefore, since the inside of the liquid separator is effectively utilized as a space for separating the liquid component contained in the reformed gas and absorbing the carbon dioxide contained in the reformed gas into the absorbent liquid, there is no need to separately provide an absorption section for absorbing the carbon dioxide contained in the reformed gas into the absorbent liquid, and the overall configuration can be simplified. Furthermore, since the carbon dioxide contained in the reformed gas, after the liquid component has been separated, is absorbed into the absorbent solution, dilution of the absorbent solution by the liquid component is avoided, and the carbon dioxide contained in the reformed gas can be recovered while being properly absorbed into the absorbent solution.

[0014] In short, the characteristic configuration of the hydrogen production apparatus of the present invention allows for the proper recovery of carbon dioxide while simplifying the overall configuration.

[0015] A further characteristic feature of the hydrogen production apparatus according to the present invention is that the reformed gas discharge section is configured as a cylindrical body with a closed top, an open bottom, and gas discharge holes in its peripheral wall.

[0016] In other words, since the reformed gas discharge section is made up of a cylindrical body with a closed top, an open bottom, and gas discharge holes in its peripheral wall, the structure of the reformed gas discharge section can be simplified.

[0017] In other words, since the reformed gas discharge section can be constructed simply by installing a cylindrical body, which is a single component, the structure of the reformed gas discharge section can be simplified.

[0018] A further characteristic feature of the hydrogen production apparatus according to the present invention is that it is provided with an absorbent liquid supply amount adjustment unit that adjusts the amount of absorbent liquid supplied to the separation and recovery unit through the absorbent liquid supply passage so as to maintain the liquid level of the absorbent liquid storage unit within an appropriate range.

[0019] That is, since the absorption liquid supply amount adjustment unit maintains the liquid level height of the absorption liquid storage unit within an appropriate range by adjusting the supply amount of the absorption liquid supplied to the separation and recovery unit through the absorption liquid supply path, the reformed gas discharge unit can cause the reformed gas supplied to the lower side of the partition part to flow to a position above the absorption liquid storage unit and discharge the same, and can appropriately supply the absorption liquid to the separation and recovery unit through the absorption liquid supply path.

[0020] That is, when the liquid level height of the absorption liquid storage unit becomes higher than the appropriate range, the reformed gas discharge unit will be buried in the absorption liquid stored in the absorption liquid storage unit, which causes the inconvenience that it becomes difficult to cause the reformed gas supplied to the lower side of the partition part to flow to a position above the absorption liquid storage unit and discharge the same by the reformed gas discharge unit. However, without causing such inconvenience, the reformed gas supplied to the lower side of the partition part can be caused to flow to a position above the absorption liquid storage unit and discharged.

[0021] Further, when the liquid level height of the absorption liquid storage unit becomes lower than the appropriate range, for example, when an absorption liquid supply pump is provided in the absorption liquid supply path to supply the absorption liquid to the separation and recovery unit through the absorption liquid supply path, hydraulic head pressure cannot be applied to the absorption liquid supply pump, which may cause inconvenience such that the absorption liquid cannot be appropriately supplied to the separation and recovery unit through the absorption liquid supply path. However, without causing such inconvenience, the absorption liquid can be appropriately supplied to the separation and recovery unit through the absorption liquid supply path.

[0022] A further characteristic configuration of the hydrogen production apparatus according to the present invention lies in that an absorption liquid return amount adjustment unit that adjusts the return amount of the absorption liquid returned to the absorption liquid supply unit through the absorption liquid return path to a target return amount is provided.

[0023] In other words, the absorbent liquid return volume adjustment unit can adjust the amount of absorbent liquid returned to the absorbent liquid supply unit through the absorbent liquid return path to a target return volume. By setting the target return volume according to the concentration of carbon dioxide contained in the reformed gas, carbon dioxide can be appropriately absorbed by the absorbent liquid, and the carbon dioxide concentration in the absorbent liquid after absorbing carbon dioxide can be adjusted to an appropriate level, allowing for proper separation of carbon dioxide in the separation and recovery unit. [Brief explanation of the drawing]

[0024] [Figure 1] This is an overall diagram showing a hydrogen production system. [Figure 2] This diagram shows the configuration of the carbon dioxide capture unit. [Figure 3] This figure shows the relationship between the amount of absorbent solution supplied and the liquid level. [Modes for carrying out the invention]

[0025] [Embodiment] Embodiments of the present invention will be described below with reference to the drawings. (Overall configuration of the hydrogen production system) As shown in Figure 1, the hydrogen production apparatus includes a reforming section AK that reforms a raw material gas G, which is a hydrocarbon gas such as natural gas or naphtha, into a reformed gas K with a high hydrogen content; a pressure fluctuation adsorption section BS equipped with an adsorption tower 1 that adsorbs components other than hydrogen from the reformed gas K from the reforming section AK onto an adsorbent to produce product gas H; a product tank U for recovering the product gas H produced in the pressure fluctuation adsorption section BS; an off-gas tank T for recovering off-gas discharged from the pressure fluctuation adsorption section BS; and an operation control section M for controlling the operation of the reforming section AK and the pressure fluctuation adsorption section BS.

[0026] The raw material gas G contains methane, carbon dioxide, carbon monoxide, and nitrogen in addition to hydrogen. As components other than hydrogen, methane, carbon dioxide, carbon monoxide, and nitrogen will be adsorbed by the adsorbent in adsorption tower 1.

[0027] (Details of the modification process) The reforming section AK is equipped with a compressor 7 (an example of a raw material gas supply section) that sends the raw material gas G introduced through the gas introduction line 7A to the desulfurizer 6 through the gas delivery line 7D, and a mixing section transport line 9 that transports the raw material gas G, which has been desulfurized in the desulfurizer 6, to the water mixing section 8. The water mixing unit 8 is configured to mix water W (pure water) supplied from a water supply unit (not shown) with the raw material gas G after desulfurization treatment. Furthermore, a raw material gas supply valve Ga is provided to intermittently supply raw material gas G to the gas introduction line 7A.

[0028] The reforming furnace R is equipped with a reforming reaction tube 2, which serves as a reformer for reforming raw material gas G into reformed gas K with a high hydrogen content by steam reforming treatment; a heating burner N for heating the reforming reaction tube 2 to a reforming reaction temperature (for example, 700°C); and an evaporation heat exchange section 11 that is heated by the combustion gas of the heating burner N.

[0029] An off-gas supply passage 4 is provided to supply off-gas stored in the off-gas tank T to the heating burner N. Although not shown in the diagram, the system is also configured to supply combustion air from an air supply unit such as a blower to the heating burner N. Furthermore, an auxiliary fuel gas passage 3 is provided to supply the raw material gas G as fuel gas to the heating burner N. Furthermore, the off-gas supply passage 4 is equipped with an off-gas shut-off valve 4A for opening and closing the off-gas supply passage 4, and the auxiliary fuel gas passage 3 is equipped with a fuel gas valve 3A for opening and closing the auxiliary fuel gas passage 3.

[0030] An evaporation transport line 12 is provided to transport the raw material gas G, which has been mixed with water in the water mixing section 8, toward the evaporation heat exchange section 11. The water mixed with the raw material gas G is heated in the evaporation heat exchange section 11 and turned into steam.

[0031] The raw material gas G, which has been heated in the evaporation heat exchange section 11 to a state containing water vapor (a state in which water vapor is mixed), is then transported to the reforming reaction tube 2 via the reaction tube transport line 13, where it is reformed into a reformed gas K with a high hydrogen content by water vapor reforming treatment. In other words, the reforming reaction tube 2 is filled with a reforming catalyst and heated to a reforming reaction temperature (for example, 700°C) by a heating burner N, so that it is reformed into a reformed gas K with a high hydrogen content by steam reforming treatment.

[0032] Incidentally, in this embodiment, the combustion gas from the heating burner N is configured to heat the reforming reaction tube 2, then flow toward the evaporation heat exchange section 11, heat the evaporation heat exchange section 11, and then be discharged through the exhaust gas passage 14.

[0033] A transformer transport line 16 is provided to transport the reformed gas K from the reforming reaction tube 2 to the CO transformer 15, and the carbon monoxide contained in the reformed gas K is converted into carbon dioxide in the CO transformer 15. The modified gas K, which has been modified in the CO transformer 15, is then supplied to the pressure fluctuation adsorption unit BS through the modified gas supply line 17.

[0034] The reformed gas supply line 17 is equipped with a cooler 18A that cools the reformed gas K with cooling water, and a liquid separator 18 that separates the liquid (condensed water) generated when the reformed gas K is cooled from the reformed gas K, so that the water in the reformed gas K is removed.

[0035] Furthermore, the hydrogen production apparatus is equipped with a carbon dioxide recovery unit that recovers carbon dioxide from the reformed gas K, which is cooled in the cooler 18A and supplied to the liquid separator 18. Details of this unit will be described later.

[0036] Furthermore, a portion (a small amount) of the reformed gas K from which water has been removed in the liquid separator 18 is supplied as hydrogen gas for desulfurization treatment in the desulfurizer 6. A recycle gas line 19 is provided to guide the reformed gas K flowing through the reformed gas supply line 17 to the upstream side of the compressor 7, i.e., to the gas introduction line 7A. A line on / off valve 19A is provided in the recycle gas line 19.

[0037] As described above, the reforming section AK is configured to produce reformed gas K by steam reforming the raw material gas G, and to supply the reformed gas K, which has undergone modification and moisture removal treatment, to the pressure fluctuation adsorption section BS. In other words, after the raw material gas G passes through the raw material gas supply valve Ga, it is pumped by the compressor 7, flows through the gas delivery line 7D, and is led to the desulfurizer 6 where it is desulfurized. After that, the raw material gas G mixed with steam is led to the reforming reaction tube 2 where it undergoes steam reforming to produce reformed gas K. The reformed gas K is reformed in the CO transformer 15, the reformed reformed gas K is cooled in the cooler 18A, and after water is removed in the liquid separator 18, it is introduced to the pressure fluctuation adsorption unit BS through the reformed gas supply line 17, where the product gas H (hydrogen gas) is purified.

[0038] (Details of the pressure fluctuation adsorption section) The pressure fluctuation adsorption unit BS is equipped with multiple (three in this embodiment) adsorption towers 1. In other words, although this embodiment exemplifies a pressure fluctuation adsorption unit BS equipped with three adsorption towers 1, the present invention can be similarly applied to configurations equipped with two or four or more adsorption towers 1. Each adsorption tower 1 is filled with a combination of adsorbents, including zeolite-based adsorbents, activated carbon, and silica gel. Each adsorption tower 1 is configured to purify a product gas with a high hydrogen gas concentration by executing the adsorption process, depressurization process, washing process, and pressurization process (PSA process) in multiple adsorption towers 1 at different phases.

[0039] Although a detailed explanation is omitted, the above process (PSA process) is executed sequentially by the operation control unit M opening and closing multiple valves (not shown) provided in each flow passage connected to the multiple adsorption towers 1. Figure 1 shows a state in which the adsorption process is being carried out in which reformed gas K flows through one adsorption tower 1 to obtain the product gas.

[0040] The product gas H, purified in the pressure fluctuation adsorption section BS, is supplied to the product tank U through the product gas transport line 22, and the product gas stored in the product tank U is stably supplied to the hydrogen usage locations. The product gas transport line 22 is equipped with a product gas valve 22A that opens and closes the product gas transport line 22. After hydrogen is separated in the pressure fluctuation adsorption section BS, the off-gas (miscellaneous gas) is supplied to the off-gas tank T via the off-gas transport line 28.

[0041] The off-gas stored in the off-gas tank T contains flammable gases such as methane and hydrogen, and is therefore supplied to the heating burner N through the off-gas supply path 4 as described above. Although Figure 1 only shows the flow of the product gas, there are timings in which the delivery of the product gas and the delivery of the off-gas occur simultaneously for different adsorption towers 1.

[0042] As described above, the pressure fluctuation adsorption unit BS uses multiple adsorption towers 1 to adsorb adsorbent components other than hydrogen from the reformed gas K onto an adsorbent to generate product gas H, and discharges the adsorbent components as off-gas in a pressure fluctuation adsorption operation. Furthermore, the system is configured to perform a pressure fluctuation adsorption operation in which an operating cycle is repeated in each of the multiple adsorption towers 1, with the operating phases of each of the multiple adsorption towers 1 being different from each other. This cycle includes an adsorption step in which reformed gas K is supplied to the adsorption tower 1 to generate product gas H, a depressurization step in which the internal gas of the adsorption tower 1 is discharged, a cleaning step in which the adsorbent of the adsorption tower 1 is cleaned with product gas H, and a pressurization step in which product gas H is supplied to the inside of the adsorption tower 1.

[0043] (Regarding the carbon dioxide capture unit) The following describes the carbon dioxide recovery unit that recovers carbon dioxide from the reformed gas K flowing into the liquid separator 18. As shown in Figure 2, the liquid separator 18 is equipped with an absorbent liquid supply nozzle 31 (an example of an absorbent liquid supply unit) that supplies an absorbent liquid that absorbs carbon dioxide downwards within the liquid separator 18, a partition unit A that receives and collects the absorbent liquid in a manner that forms an absorbent liquid storage unit 25, located above the liquid storage unit 18a at the bottom of the liquid separator 18 where the liquid is stored, and a reformed gas discharge unit B that causes the reformed gas K supplied to the lower side of the partition unit to flow to a location above the absorbent liquid storage unit 25 and discharge it.

[0044] Incidentally, the upstream portion 17a of the liquid separator 18 in the reformed gas supply line 17 is connected to a location corresponding to the space between the liquid storage section 18a and the partition section A. The downstream portion 17b of the liquid separator 18 in the reformed gas supply line 17 is connected to a location above the absorbent liquid storage section 25.

[0045] Inside the liquid separator 18, when the absorbent liquid is distributed from the absorbent liquid supply nozzle 31, the reformed gas K flowing upward comes into contact with the absorbent liquid, and carbon dioxide is absorbed by the absorbent liquid. The absorbent liquid that has absorbed carbon dioxide is then stored in the absorbent liquid storage section 25. Furthermore, an absorbent packing material 27 is provided inside the liquid separator 18 to bring the absorbent liquid and the reformed gas K into contact on its surface.

[0046] Partition section A is formed by installing a plate-like partition in a horizontal position inside the liquid separator 18. The plate-like partition has an opening for installing the reformed gas discharge section B. The reformed gas discharge section B is composed of a cylindrical body 26 with a closed top and an open bottom, and a gas discharge hole 26a in its peripheral wall. The cylindrical body 26 is installed on top of partition section A with its bottom opening aligned with the opening in partition section A.

[0047] Furthermore, a regeneration tower Q (an example of a separation and recovery section) is provided to separate and recover carbon dioxide from the absorbent liquid that has absorbed it. Furthermore, the system includes an absorbent liquid supply path La that supplies the absorbent liquid, which has absorbed carbon dioxide stored in the absorbent liquid storage section 25, to the regeneration tower Q, and an absorbent liquid return path Lb that returns the absorbent liquid from which carbon dioxide has been separated from the regeneration tower Q to the absorbent liquid supply nozzle 31.

[0048] In other words, the carbon dioxide recovery unit recovers carbon dioxide from the reformed gas K containing carbon dioxide by absorbing and separating it into an absorbent liquid using the CO2 chemical absorption separation method inside the liquid separator 18. The absorbent liquid that has absorbed carbon dioxide is then supplied to the regeneration tower Q through the absorbent liquid supply path La, where the carbon dioxide absorbed by the absorbent liquid is separated from the absorbent liquid and recovered. The absorbent liquid from which carbon dioxide has been separated in the regeneration tower Q is then returned to the absorbent liquid supply nozzle 31 through the absorbent liquid return path Lb.

[0049] As the absorbent solution used in the above CO2 chemical absorption separation method, for example, an amine absorbent solution can be used, which employs monoethanolamine (MEA) or diethanolamine (DEA) as the solute and water as the solvent. In this embodiment, the absorbent liquid that has absorbed carbon dioxide may be referred to as the rich absorbent liquid, and the absorbent liquid from which carbon dioxide has been separated in the regeneration tower Q and which is capable of absorbing carbon dioxide may be referred to as the lean absorbent liquid. The rich absorbent liquid and the lean absorbent liquid differ in their carbon dioxide absorption capacity. Furthermore, the term "absorbent solution" refers to either a lean absorbent solution, a rich absorbent solution, or a mixture of a lean absorbent solution and a rich absorbent solution.

[0050] The absorbent liquid supply path La is equipped with an absorbent liquid supply pump 33 for supplying the rich absorbent liquid from the absorbent liquid storage section 25 to the regeneration tower Q. Furthermore, the absorbent liquid supply volume control unit Da, which controls the operation of the absorbent liquid supply pump 33, is configured to control the rotation speed of the absorbent liquid supply pump 33 by an inverter based on detection information from a liquid level sensor 35 that detects the liquid level in the absorbent liquid storage unit 25, and detection information from a first flow sensor 36 that detects the flow rate of the rich absorbent liquid in the absorbent liquid supply path La. Details of this will be described later.

[0051] The absorbent liquid return path Lb is equipped with an absorbent liquid return pump 37 for returning the lean absorbent liquid, from which carbon dioxide has been separated in the regeneration tower Q, to the absorbent liquid supply nozzle 31. Furthermore, the absorbent liquid return volume control unit Db, which controls the operation of the absorbent liquid return pump 37, is configured to control the rotation speed of the absorbent liquid return pump 37 by an inverter based on detection information from a second flow sensor 38 that detects the flow rate of lean absorbent liquid in the absorbent liquid return path Lb. Details of this will be described later.

[0052] A heat exchanger 39 is provided between the absorbent liquid supply path La and the absorbent liquid return path Lb, which cools the lean absorbent liquid and heats the rich absorbent liquid. Furthermore, the absorbent return path Lb is equipped with an absorbent cooler 40 that further cools the lean absorbent cooled in the heat exchanger 39.

[0053] (Regarding the regeneration tower) The regeneration tower Q separates carbon dioxide from the rich absorbent, regenerating it into a lean absorbent, and also releases the separated carbon dioxide. This released carbon dioxide is recovered in the gas supply channel P and supplied to an external treatment device (not shown). Then, the lean absorbent liquid stored in the liquid reservoir Qa at the bottom of the regeneration tower Q is returned to the absorbent liquid supply nozzle 31 through the absorbent liquid return path Lb.

[0054] The absorbent liquid supply path La is connected to a rich absorbent liquid nozzle 45 located in the middle of the regeneration tower Q. The rich absorbent liquid nozzle 45 supplies the rich absorbent liquid downwards. Below the rich absorbent liquid nozzle 45, the lower regeneration tower packing material 46 is provided. The absorbent liquid (rich absorbent liquid) flowing down the surface of the lower regeneration column packing material 46 comes into gas-liquid contact with the vapor of the solute and solvent (e.g., water) of the absorbent liquid, and a mixed gas of this vapor and carbon dioxide, which are rising inside the regeneration column Q. After that, it is stored in the liquid reservoir Qa at the bottom of the regeneration column Q. The mixed gas is discharged from the top of regeneration tower Q.

[0055] Furthermore, the regeneration tower Q is equipped with a regeneration heating section V that heats the absorbent liquid extracted from the liquid reservoir Qa at the bottom with heated steam and returns it to the regeneration tower Q. In other words, a heating channel 42 is provided that allows the absorbent liquid taken from the liquid reservoir Qa to flow into the regeneration tower Q via the heater body 41. A steam supply passage 44 is connected to the heater body 41 to supply heated steam (for example, saturated steam).

[0056] Furthermore, a mixed gas cooling system E is provided at the top of the regeneration tower Q. This system cools the mixed gas described above by drawing it out from the top of the tower, cooling it, and reintroducing the condensed liquid, which contains the vaporized solute and solvent components, into the regeneration tower Q, while also releasing uncondensed carbon dioxide.

[0057] The mixed gas cooling system E includes a gas-liquid separator 47 for separating condensate and carbon dioxide, and a mixed gas flow path 48 connecting the top of the regeneration tower Q to the gas phase of the gas-liquid separator 47. The aforementioned gas supply path P extends from the top of the gas-liquid separator 47. The mixed gas flow path 48 is equipped with a mixed gas cooler 49 that cools the mixed gas with cooling water.

[0058] An upper regeneration column packing material 50 is positioned above the rich absorbent nozzle 45, and a condensate nozzle 51 is positioned above the upper regeneration column packing material 50. A condensate flow path 52, which connects the liquid phase of the gas-liquid separator 47 to the condensate nozzle 51, is provided with a condensate water supply pump 5332. The condensate water flowing down the surface of the upper regeneration column packing material 50 comes into gas-liquid contact with the vapor components of the solute and solvent (e.g., water) of the absorbent liquid rising inside the regeneration column Q, as well as a mixed gas of these vapor components and carbon dioxide.

[0059] In other words, inside the regeneration tower Q, the rich absorbent liquid supplied from the rich absorbent liquid nozzle 45 descends through the interior. Also, the absorbent liquid heated by the regeneration heating unit V is reintroduced from the bottom of the regeneration tower Q. At this time, some of the solute and solvent in the heated absorbent liquid turn into vapor, and the regenerated carbon dioxide turns into gas and rises inside the regeneration tower Q. During this rising process, the rich absorbent liquid comes into contact with the vapors of the solute and solvent, and an endothermic reaction of desorption regeneration occurs using the heat of condensation of the vapors of the solute and solvent as a heat source, separating carbon dioxide from the rich absorbent liquid.

[0060] This separates the rich absorbent into a lean absorbent and carbon dioxide. Of these, the carbon dioxide mixes with the vapors of the solute and solvent to form a mixed gas, which rises inside the regeneration tower Q. This mixed gas is introduced into the mixed gas flow path 48 of the mixed gas cooling system E, and is cooled in the mixed gas cooler 49 as it flows through the mixed gas flow path 48. This cooling process causes the vapors of the solute and solvent in the mixed gas to condense into a condensate, which is then separated from the carbon dioxide-dominant gas by the gas-liquid separator 47. The condensate is then reintroduced into the regeneration tower Q through the condensate nozzle 51, while the carbon dioxide (carbon dioxide-dominant gas) is released to the outside through the gas supply path P.

[0061] Meanwhile, the absorbent liquid descending inside the regeneration tower Q is stored in the liquid reservoir Qa at the bottom of the regeneration tower Q, and then discharged from the regeneration tower Q as separated and regenerated lean absorbent liquid, which is supplied to the absorbent liquid supply nozzle 31 inside the off-gas tank T via the absorbent liquid return path Lb.

[0062] (Control configuration of the carbon dioxide capture unit) The absorbent liquid return volume control unit Db, which controls the operation of the absorbent liquid return pump 37, is configured to control the operation of the absorbent liquid return pump 37 based on detection information from a second flow sensor 38 that detects the flow rate of the lean absorbent liquid, in order to adjust the amount of absorbent liquid (lean absorbent liquid) returned from the regeneration tower Q through the absorbent liquid return path Lb to the absorbent liquid supply nozzle 31 to a target return volume. In other words, the rotation speed of the absorbent liquid return pump 37 is controlled by an inverter. In this embodiment, the main component is the absorbent liquid return volume control unit Db, and the absorbent liquid return volume adjustment unit Fb is configured to adjust the amount of absorbent liquid (lean absorbent liquid) returned from the regeneration tower Q through the absorbent liquid return path Lb to the absorbent liquid supply nozzle 31 to a target return volume.

[0063] In other words, the target return amount is set according to the concentration of carbon dioxide contained in the reformed gas K. The amount of absorbent liquid (lean absorbent liquid) returned from the regeneration tower Q through the absorbent liquid return path Lb to the absorbent liquid supply nozzle 31 is adjusted to the target return amount, thereby appropriately absorbing the carbon dioxide contained in the reformed gas K and maintaining the concentration of carbon dioxide in the absorbent liquid at a concentration suitable for separating carbon dioxide in the regeneration tower Q.

[0064] Incidentally, when the operation control unit M controls the operation of the compressor 7 to adjust the supply amount of raw material gas G per unit time, it is preferable that the information for adjusting the supply amount of raw material gas G is transmitted to the absorbent liquid return amount control unit Db, and the absorbent liquid return amount control unit Db increases or decreases the target return amount.

[0065] The absorbent liquid supply volume control unit Da, which controls the operation of the absorbent liquid supply pump 33, is configured to control the operation of the absorbent liquid supply pump 33 based on the detection information from the liquid level sensor 35 and the detection information from the first flow rate sensor 36, in order to maintain the liquid level in the absorbent liquid storage unit 25 within an appropriate range. In other words, the rotation speed of the absorbent liquid supply pump 33 is controlled by an inverter. In this embodiment, the main component is the absorbent liquid supply control unit Da, and the absorbent liquid supply adjustment unit Fa is configured to adjust the amount of absorbent liquid supplied to the regeneration tower Q through the absorbent liquid supply path La so as to maintain the liquid level in the liquid storage unit Ta within an appropriate range.

[0066] In other words, as shown in Figure 3, the appropriate range for the liquid level height of the absorbent liquid reservoir 25 is set to be greater than the minimum height Lmin and less than the maximum height Lmax. When the liquid level detected by the liquid level sensor 35 is within the appropriate range, the absorbent liquid supply control unit Da controls the rotation speed of the absorbent liquid supply pump 33 using an inverter to set the amount of absorbent liquid supplied to Fave, which is the average flow rate of the maximum supply amount Fmax and the minimum supply amount Fmin. Furthermore, the system is configured to control the rotation speed of the absorbent liquid supply pump 33 by an inverter so that when the liquid level detected by the liquid level sensor 35 exceeds the maximum height Lmax, the amount of absorbent liquid supplied is set to the maximum supply amount Fmax, and when the liquid level detected by the liquid level sensor 35 falls below the minimum height Lmin, the amount of absorbent liquid supplied is set to the minimum supply amount Fmin.

[0067] [Another embodiment] Next, we will list other embodiments. (1) In the above embodiment, a pressure fluctuation adsorption section BS is exemplified as having three adsorption towers 1, but the present invention can also be applied when the pressure fluctuation adsorption section BS is configured to have two or four or more adsorption towers 1.

[0068] (2) In the above embodiment, an example was given in which water is mixed with the raw material gas G and then the mixed water is evaporated in the evaporation heat exchange unit 11. However, it may also be implemented in which pre-generated water vapor is mixed with the raw material gas G.

[0069] (3) In the above embodiment, a counterflow gas-liquid contact type regeneration tower Q was exemplified as the separation and recovery section, but various types of separation and recovery sections can be applied, such as those that separate and recover carbon dioxide using hollow fiber membranes.

[0070] (4) In the above embodiment, an example was given in which the absorbent liquid return volume control unit Db controls the amount of absorbent liquid returned by controlling the rotation speed of the absorbent liquid return pump 37 with an inverter. However, the absorbent liquid return pump 37 may also be equipped with a spillback bypass path with a flow control valve, and the amount of absorbent liquid returned may be controlled by adjusting the opening degree of the flow control valve.

[0071] (5) In the above embodiment, an example was given in which the absorbent liquid supply amount control unit Da controls the amount of absorbent liquid supplied by controlling the rotation speed of the absorbent liquid supply pump 33 with an inverter. However, the absorbent liquid supply pump 33 may also be equipped with a spillback bypass path with a flow control valve, and the amount of absorbent liquid supplied may be controlled by adjusting the opening degree of the flow control valve.

[0072] (6) In the above embodiment, an example was given in which an absorbent liquid supply pump 33 is provided. However, instead of the absorbent liquid supply pump 33, a flow control valve may be provided in the absorbent liquid supply path La, and the absorbent liquid supply amount control unit Da may adjust the opening degree of the flow control valve to control the amount of absorbent liquid supplied. In other words, since the absorbent liquid flowing from the absorbent liquid storage section 25 into the absorbent liquid supply passage La is pressed into the absorbent liquid supply passage La by the internal pressure of the liquid separator 18, the amount of absorbent liquid supplied can be controlled by adjusting the opening of the flow control valve if the absorbent liquid can be pushed into the absorbent liquid supply passage La with sufficient pressure to supply it to the regeneration tower Q.

[0073] Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise. Moreover, the embodiments disclosed herein are illustrative, and the embodiments of the present invention are not limited thereto, and can be modified as appropriate without departing from the object of the present invention. [Explanation of Symbols]

[0074] 1 Adsorption tower 2. Reformer 4. Off-gas supply line 7. Raw Material Gas Supply Department 18 Liquid separator 18A cooling section 18a Liquid storage section 25 Absorbent liquid reservoir 26. Cylindrical body 26a Gas outlet 31 Absorbent liquid supply unit A partition B. Reformed Gas Discharge Section AK Modification Processing Unit BS pressure fluctuation adsorption unit Fa Absorbent liquid supply volume adjustment unit Fb Absorbent liquid return volume adjustment unit La absorbent liquid supply channel Lb absorbent return path N heating burner Q Separation and Recovery Section

Claims

1. A reforming processing unit comprising a raw material gas supply unit that supplies raw material gas containing hydrogen and carbon dioxide, and a reformer that generates a reformed gas with a high hydrogen content by steam reforming the raw material gas while it is heated to a reforming temperature by a heating burner, A cooling unit for cooling the reformed gas from the reforming section, A liquid separator for separating the liquid component from the reformed gas cooled in the cooling unit, A hydrogen production apparatus comprising: a pressure fluctuation adsorption section equipped with multiple adsorption towers that perform pressure fluctuation adsorption operation to generate a product gas by adsorbing adsorbable components other than the hydrogen component onto an adsorbent from the reformed gas from which the liquid component has been separated by the liquid separator, and discharging the adsorbable components as off-gas, An absorbent liquid supply unit that supplies the absorbent liquid that absorbs carbon dioxide downwards inside the liquid separator, A partition is provided above the liquid storage section at the bottom of the liquid separator where the liquid is stored, in which an absorbent liquid storage section is formed, to receive and collect the absorbent liquid. A modified gas discharge section that causes the modified gas supplied to the lower side of the partition to flow to the upper part of the absorbent liquid storage section and discharge it, A separation and recovery unit for separating and recovering the carbon dioxide from the absorbent liquid that has absorbed the carbon dioxide, An absorbent liquid supply path supplies the absorbent liquid, which has absorbed carbon dioxide and is stored in the absorbent liquid storage section, to the separation and recovery section. A hydrogen production apparatus comprising: an absorbent liquid return path for returning the absorbent liquid from which the carbon dioxide has been separated from the absorbent liquid from the separation and recovery unit to the absorbent liquid supply unit.

2. The hydrogen production apparatus according to claim 1, wherein the reformed gas discharge section is configured as a cylindrical body having a closed top, an open bottom, and gas discharge holes in its peripheral wall.

3. The hydrogen production apparatus according to claim 1 or 2, further comprising an absorbent liquid supply amount adjustment unit that adjusts the amount of absorbent liquid supplied to the separation and recovery unit through the absorbent liquid supply path so as to maintain the liquid level of the absorbent liquid storage unit within an appropriate range.

4. The hydrogen production apparatus according to claim 1 or 2, further comprising an absorbent liquid return volume adjustment unit that adjusts the amount of absorbent liquid returned to the absorbent liquid supply unit through the absorbent liquid return path to a target amount.

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