JP2006001750A - Hydrogen generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a catalyst from degrading for enhancing reliability to durability in a hydrogen generator. <P>SOLUTION: This hydrogen generator is equipped with a reforming section 1 with a heating means to heat up raw materials and water, a CO-converting section 6 and a CO-removing section 7 sequentially connected to the reforming section 1, a bypass pipe 12 connecting a gas outlet port and a gas inlet port of the reforming section 1, and a transport means 13 disposed to the bypass pipe 12. By this configuration, supplied raw materials can pass through the reforming section 1 a plurality of times, thereby the raw materials flow can be brought into contact with whole of the catalyst, so that the reaction can be accelerated by substantially reducing an SV value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hydrogen generator used as a fuel for a polymer electrolyte fuel cell, and more particularly to a hydrogen generator that reforms a predetermined raw material using water vapor to generate hydrogen gas.

  Hydrogen generators use hydrogen as a fuel for solid polymer fuel cells, which are being developed recently, and a hydrocarbon steam reforming method is often used as a method for producing this hydrogen. The steam reforming method is a method in which methane, ethane, propane, butane, city gas, LP gas, natural gas, and other hydrocarbon gases are reformed with steam to generate a hydrogen-rich reformed gas. In the steam reforming method, these hydrocarbons are converted into hydrogen-rich reformed gas by a catalytic reaction in the reforming section. The obtained hydrogen-rich reformed gas is used after reducing CO in the CO removal section.

  FIG. 5 is a block diagram showing a raw material using a steam reformer, from supply of steam to the outlet of hydrogen gas. It comprises a heating section having a combustion section and a reforming section having a reforming catalyst. In the reforming section that has reached a high temperature, the hydrocarbon reacts with the steam to produce a hydrogen-rich reformed gas. When the hydrocarbon is used as a raw material, the reforming section needs to be heated to a temperature of 500 to 700 ° C. As the reforming catalyst, for example, a Ni-based or Ru-based catalyst is used. Since the reforming catalyst is poisoned by sulfur compounds in the raw material gas and deteriorates its performance, the raw material gas is first introduced into the desulfurization section in order to remove these sulfur compounds.

  Next, steam from a steam generation section provided separately is added and mixed to be introduced into the reforming section of the steam reformer. The reforming reaction when the raw material gas is methane is represented by CH4 + 2H2O → CO2 + 4H2. The generated reformed gas contains about 8 to 15% of carbon monoxide (CO) generated in addition to unreacted methane, unreacted water vapor, and generated carbon dioxide. For this reason, the reformed gas is applied to the CO conversion section to remove the carbon monoxide by converting it to carbon dioxide and hydrogen. For example, a Fe—Cr based catalyst, a Cu—Zn based catalyst, or a Pt catalyst is used in the CO conversion portion. The reaction in the CO conversion part is CO + H 2 O → CO 2 + H 2, and the steam necessary for the steam uses the residual steam in the reforming part. The reformed gas exiting from the CO conversion section is composed of unreacted methane, excess steam, hydrogen, and carbon dioxide.

  However, this reformed gas does not completely remove CO, but contains CO although it is about 1% or less. The allowable concentration of CO in the fuel hydrogen supplied to the fuel cell is about 10 ppm, and if it exceeds this, the cell performance is significantly deteriorated. Therefore, it is necessary to remove the CO component as much as possible before introducing it into the fuel cell. For this reason, the reformed gas is applied to the CO removal section after the CO concentration is lowered to around 1% by the CO shift section. An oxidant such as air is added to the CO removing unit, and CO is removed by changing the CO gas from 2CO + O 2 → 2CO 2 and CO 2 to reduce the CO concentration of the reformed gas to 10 ppm or less.

  Conventionally, this type of hydrogen generator has attracted attention for uniformly mixing raw materials and water vapor in order to improve performance (for example, see Patent Document 1).

  FIG. 6 is a cross-sectional view of the reforming reactor of the steam reformer. The reforming reactor is provided with a raw material evaporation introducing portion 3 that leads to the reforming reaction portion 2 as a mixed raw material gas that is uniformly mixed with a gaseous raw material that is separately supplied while vaporizing a liquid raw material, in the upper part of the cylindrical container 1. The lower part in the container 1 is provided with a reforming reaction part 2 for reforming the mixed raw material gas by the reforming catalyst and a heating part 4 for supplying reaction heat to the reforming reaction part 2. The reforming reaction section 2 is formed in a cylindrical shape as a whole, and is disposed coaxially with the cylindrical container 1 with a slight space between the bottom of the container 1 and the bottom surface of the container 1. The heating unit 4 includes a combustor 5 provided on the bottom surface of the container 1, a combustion gas passage 6 through which the combustion gas of the combustor 5 passes upward along the axis of the container 1, and the combustion gas. And an exhaust pipe 7 provided on the upper surface of the container 1 in order to exhaust the air from the container 1.

  For this reason, the reforming raw material of the reforming reactor, that is, the mixed raw material gas is steam (water) obtained by vaporizing methane as a gas raw material and water as a liquid raw material. Water is dropletized and mixed into the supplied methane, and the dropped water becomes fine water droplets and rides on the flow of methane. 3 is supplied. In the course of flowing down the raw material evaporation introducing unit 3, the gas / liquid mixed phase is vaporized (evaporated) in the gas / liquid mixed phase, and the gas / liquid mixed phase becomes mixed raw material gas, which is supplied to the reaction unit 2. Is done.

  That is, the evaporation in the raw material evaporation introducing unit 3 is an evaporation mode in which moisture is humidified to the saturated vapor pressure in the methane gas phase while the boiling point is sequentially changed in the flow direction of the raw material due to the presence of methane as the second component. Thus, stable evaporation can always be realized at a constant evaporation rate.

Therefore, it is always possible to supply a uniform mixed raw material gas without pulsation that is uniformly mixed. In addition, since a stable mixed source gas without pulsation is supplied, battery voltage fluctuations and stable combustion of the heating unit 4 of the reforming reaction unit 2, that is, generation of CO, NO, and the like are suppressed, and the system is operated. It can be performed stably. Moreover, since the reforming reaction gas as the mixed raw material gas is supplied to the reforming reaction section 2 with a uniform composition, carbon deposition on the reforming catalyst and a decrease in the reforming rate are suppressed as in the conventional case.
JP 2003-119001 A

  However, in the conventional configuration, a stable mixed raw material gas without pulsation in which methane as a gas raw material and steam (water) in which water as a liquid raw material is vaporized is uniformly mixed can be supplied to the reforming unit. . Therefore, the battery voltage fluctuation, the stable combustion of the heating unit 4 of the reforming reaction unit 2, the operation of the system can be performed stably, and the carbon deposition on the reforming catalyst and the reduction of the reforming rate can be suppressed.

  On the other hand, since the reforming section is configured to promote the reaction between the raw material and water vapor by the catalyst, it is important for the catalyst filled in the reforming section to ensure a passage where the raw material and water vapor are in contact and to have a heating structure corresponding to the endothermic reaction. It is. For this reason, the reforming section has a catalyst supported on a number of granular carriers, and the raw material and water vapor enter from the catalyst inlet of the reforming section and reach the outlet through the catalyst particles.

  However, the raw material flowing in the reforming section and water vapor drifted, and sufficient performance could not be ensured. That is, a large amount of raw material and steam flow from the inlet to the outlet in the vicinity of the shortest distance. In addition, due to the repetition of heat due to initial filling and operation, the arrangement of the catalyst particles is biased, and the size between the catalyst particles is biased. For this reason, the raw material and water vapor flow in many places with large gaps.

  For this reason, the raw material and water vapor do not flow in some of the catalyst in the reforming section, and the raw material and water vapor flow excessively in the other part of the catalyst, and the SV value (reaction gas flow rate is the volume of the catalyst). If this value is small, the reaction gas will flow slowly through the catalyst and can react sufficiently, but the amount of catalyst will increase), and it will leave the reforming section before it becomes sufficiently catalytic. Will go. Therefore, the reforming efficiency is lowered, and deterioration due to an excessive load on the reforming catalyst occurs, so that long-term reliability cannot be ensured and the system efficiency is lowered.

  The present invention solves the above-mentioned conventional problems, and at least a part of the raw material is repeatedly passed through the reforming section a plurality of times and repeatedly undergoes a reforming reaction, thereby improving the reforming efficiency and deteriorating the catalyst. An object of the present invention is to provide a hydrogen generator that is excellent in durability and reliability.

  In order to solve the above-described conventional problems, the hydrogen generator of the present invention sequentially connects a reforming unit that supplies raw materials and water and has a heating means, a CO conversion unit, and a CO removal unit, The gas outlet part and the gas inlet part are connected to a bypass pipe via a conveying means. Thus, the reforming reaction can be repeated by allowing the raw material to pass through the reforming section a plurality of times. For this reason, the flow rate of the raw material flowing through the reforming section is increased so that the flow is uniform throughout the catalyst, so that the entire catalyst is utilized and overload is prevented. Since the reaction can be promoted, an efficient system by improving the reforming efficiency and deterioration of the catalyst can be prevented, and a highly reliable hydrogen generator can be obtained.

  The hydrogen generator according to the present invention is provided with a reforming unit having a heating means for raising the temperature of the raw material and water, a CO conversion unit and a CO removal unit sequentially connected to the reforming unit, and the reforming unit. Provided with a bypass pipe connecting the outlet part and the inlet part, and a conveying means provided in the bypass pipe, the raw material can be passed through the reforming part multiple times. Since the raw material flowing through the part is in contact with the entire catalyst, the entire catalyst is effectively utilized to prevent overload, and the reaction can be promoted by substantially reducing the SV value. That is, by improving the reforming efficiency, it is possible to realize a highly durable and reliable hydrogen generator that prevents deterioration of the catalyst.

  According to the first aspect of the present invention, a reforming unit that supplies a raw material and water and has a heating means, a CO conversion unit, and a CO removal unit are sequentially connected, and an outlet and an inlet of the reforming unit are connected. The bypass pipe is configured via a conveying means. Thus, the reforming reaction can be repeated by allowing the raw material to pass through the reforming section a plurality of times. For this reason, the flow rate of the raw material flowing through the reforming section is increased so that the flow is uniform throughout the catalyst, so that the entire catalyst is utilized and overload is prevented. Since the reaction can be promoted, an efficient system by improving the reforming efficiency and deterioration of the catalyst can be prevented, and a highly reliable hydrogen generator can be obtained.

  The invention according to claim 2 is particularly configured such that the hydrogen generator according to claim 1 is connected to a bypass pipe via a solenoid valve or a check valve, and the solenoid valve or the check valve is operated during the operation of the conveying means. By opening and closing when the conveying means is stopped, the bypass pipe can be surely opened during operation and closed when operation is stopped to prevent inflow of raw material gas and water vapor into this system. . Therefore, when the operation of the bypass pipe is stopped, high efficiency can be maintained without condensing and collecting water vapor in this pipe. Further, the bypass pipe can be closed, the shortcut of the raw material gas is eliminated, the catalyst deterioration of the reforming section, the CO conversion section, and the CO removal section due to gas movement can be prevented, and the durability reliability is improved.

  The invention described in claim 3 operates the conveying means at least when the hydrogen generator according to claim 1 increases or decreases the amount of hydrogen generated. Thereby, even if the amount of hydrogen generation increases or decreases, the conversion can be increased and the reaction can be stabilized. That is, if the hydrogen generator increases or decreases the amount of hydrogen generated to increase or decrease the amount of generated hydrogen, the temperature of the reforming section changes due to the increase or decrease in heating and endothermic amount, and the evaporation of water vapor. Delay, non-uniform mixing with the raw material gas, and a partial decrease in S / C occurred. Therefore, when increasing or decreasing the amount of hydrogen generated, the conveying means is operated and gas is circulated through the bypass pipe to increase the gas flow rate through the reforming section so that the flow of the entire catalyst is uniform. Utilization and the flow of raw materials to the reforming section multiple times can reduce the actual SV value and promote the reaction, making it possible to keep the conversion rate stable and high, and prevent stable system and catalyst deterioration. This makes it a highly durable and reliable device with excellent operability and reliability.

  In the invention according to claim 4, the hydrogen generator according to claims 1 to 3, particularly, the flow rate of flowing through the reforming section is constantly increased by increasing or decreasing the flow rate of the bypass pipe according to the increase or decrease of the hydrogen generation amount. As a result, the system can be more stable against changes in the raw material gas flow rate, and the system has a better operational response to the load, and is a device with better operability and reliability. That is, even if the amount of generated hydrogen is changed according to the load, the sum of the raw material gas flowing through the reforming section and the gas from the bypass is constant, and the flow rate can always be the same. For this reason, there is no delay in evaporation of water vapor caused by changes in flow rate, non-uniform mixing with the raw material gas, or a partial decrease in S / C, and the system has good operational response to the load, operability and reliability. Can improve the performance.

  In the invention according to claim 5, the hydrogen generator according to claim 1 is constituted by insulating the bypass pipe. The gas coming out of the reforming part contains a lot of water vapor, and if it dissipates heat in the bypass pipe, it liquefies and closes the bypass pipe, or the S / C of the gas returning to the reforming part decreases and inhibits the hydrogen reforming reaction To do. In addition, when the heat is radiated through the bypass pipe, the temperature of the gas returning to the reforming section decreases, the energy for raising the reforming section to maintain the reforming reaction increases, and the reforming efficiency decreases. By insulating the bypass pipe, it is possible to prevent the cooling of the gas coming out of the reforming section, returning to the reforming section through the bypass pipe, keeping the hydrogen reforming efficiency high and stable, and preventing heat dissipation. It becomes a highly efficient system.

  The invention described in claim 6 is the hydrogen generator according to claim 1, in particular, because the bypass pipe is configured with a heating means, so that the gas emitted from the reforming section can be heated and radiated and liquefied by the bypass pipe. It is possible to prevent the hydrogen reforming reaction from being inhibited by closing the bypass pipe or reducing the S / C of the gas returning to the reforming section. For this reason, it is possible to prevent moisture condensation of the gas that comes out of the reforming section and returns to the reforming section through the bypass pipe, and the hydrogen reforming efficiency is kept high and stable, resulting in a highly efficient system.

  In the invention according to claim 7, in particular, since the hydrogen generator according to claim 1 is provided with a heating means and a temperature detection means in the bypass pipe, the temperature of the bypass pipe is measured by the temperature detection means and the heating means is set. It can be operated. For this reason, the bypass pipe is overheated by the heating means and becomes high temperature, the gas in the bypass pipe is overheated and carbon is precipitated, or the bypass pipe is not heated enough to become low temperature and the water vapor in the gas in the bypass pipe is liquefied. It is possible to prevent the S / C of the gas returning to the reforming section from being blocked by blocking the bypass pipe and preventing the hydrogen reforming reaction, and the hydrogen reforming efficiency is kept high and stable, resulting in a highly efficient system.

  In the invention described in claim 8, in particular, in the hydrogen generator according to claim 1, at least one of the CO conversion section and the CO removal section is provided with an outlet section and an inlet section through which the reformed raw material passes, and these The present invention is characterized in that a conveying means is provided in a bypass pipe that connects the outlet portion and the inlet portion. This allows the source gas to be repeatedly passed through at least one of the CO conversion section and the CO removal section, thereby repeatedly performing the conversion reaction or selective oxidation reaction. For this reason, the flow rate of the raw material gas flowing through at least one of the CO conversion section and the CO removal section is increased so that the flow is uniform over the entire catalyst, preventing the entire catalyst from being used and overloading. Since the actual SV value can be reduced and the reaction can be promoted by flowing multiple times in at least one of the parts, the transformation reaction or the selective oxidation reaction is promoted to prevent the efficient system and catalyst from being deteriorated by improving the reforming efficiency. It becomes a hydrogen generator with high durability and reliability.

  The invention according to claim 9 is configured such that the hydrogen generator according to claim 8 is connected to the bypass pipe via an electromagnetic valve or a check valve, and the electromagnetic valve or check valve is not operated during the operation of the conveying means. By opening and closing when the conveying means is stopped, the bypass pipe can be surely opened during operation and closed when operation is stopped to prevent inflow of raw material gas and water vapor into this system. . Therefore, when the operation of the bypass pipe is stopped, high efficiency can be maintained without condensing and collecting water vapor in this pipe. Further, the bypass pipe can be closed, the shortcut of the raw material gas is eliminated, the catalyst deterioration of the reforming section, the CO conversion section, and the CO removal section due to gas movement can be prevented, and the durability reliability is improved.

  The invention according to claim 10 is a flow rate at which the hydrogen generator according to claims 8 and 9 increases or decreases the flow rate of flowing through the bypass pipe in accordance with the increase or decrease in the amount of hydrogen generated, and flows through the CO conversion section or CO removal section. By always maintaining a constant amount, the system can be more stable with respect to changes in the raw material gas flow rate, and the system has a better operational response to the load, and becomes a device with better operability and reliability. That is, even if the amount of generated hydrogen is changed according to the load, the sum of the raw material gas flowing through the CO conversion section or the CO removal section and the gas from the bypass is constant, and the flow rate can always be the same. For this reason, there is no delay in evaporation of water vapor caused by changes in flow rate, non-uniform mixing with the raw material gas, or a partial decrease in S / C, and the system has good operational response to the load, operability and reliability. Can improve the performance.

  In the eleventh aspect of the present invention, in particular, the bypass pipe of the hydrogen generator according to the eighth to tenth aspects is insulated. The gas exiting from the CO conversion section or the CO removal section contains a large amount of water vapor, and when the heat is radiated in the bypass pipe, it liquefies and closes the bypass pipe, or the S / C of the gas returning to the CO conversion section or the CO removal section is It decreases and inhibits hydrogen reforming reaction. In addition, when the heat is radiated by the bypass pipe, the temperature of the gas returning to the CO conversion section or the CO removal section is reduced, and the energy for increasing the temperature of the CO conversion section or the CO removal section to maintain the reforming reaction is increased. Selective oxidation efficiency decreases. By bypassing the bypass pipe, it is possible to prevent cooling of the gas that exits the CO conversion section or CO removal section and returns to the re-CO conversion section or CO removal section through the bypass pipe, and keeps the hydrogen generation efficiency high and stable. , Prevents heat dissipation and becomes a highly efficient system.

  In the invention described in claim 12, in particular, the hydrogen generator according to claims 8-11 is provided with a heating means in the bypass pipe so that the gas emitted from the CO conversion section or the CO removal section can be heated. It is possible to prevent the hydrogen reforming reaction from being inhibited by reducing the S / C of the gas returning to the CO conversion section or the CO removal section by blocking the bypass pipe by radiating and liquefying. For this reason, it is possible to prevent moisture dew condensation of the gas that comes out of the CO conversion section or the CO removal section and returns to the CO conversion section or the CO removal section again through the bypass pipe, and it becomes a highly efficient system that keeps the hydrogen generation efficiency high and stable. .

  In the invention described in claim 13, the hydrogen generator according to claim 12 is provided with a heating means and a temperature detection means in the bypass pipe, and the temperature of the bypass pipe is measured by the temperature detection means. It can be operated. For this reason, the bypass pipe is overheated by the heating means and becomes high temperature, the gas in the bypass pipe is overheated and carbon is precipitated, or the bypass pipe is not heated enough to become low temperature and the water vapor in the gas in the bypass pipe is liquefied. A high-efficiency system that can block the bypass pipe or prevent the S / C of the gas returning to the CO conversion section or CO removal section from lowering and inhibiting the hydrogen reforming reaction, and maintaining a high and stable hydrogen production rate. Become.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiment.

(Embodiment 1)
FIG. 1 is a block diagram of a hydrogen generator according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a reforming unit, which is connected to a hydrocarbon-based raw material (hereinafter referred to as raw material) supply unit 3, a water supply unit 4, and a heating unit 5 via a desulfurization unit 2. Reference numeral 6 denotes a CO conversion unit, and 7 denotes a CO removal unit. The CO conversion unit 6 and the CO removal unit 7 are sequentially connected to the fuel cell 8 from the reforming unit 1. The heating means 5 includes a combustion section 9 that generates heat and a heat exchange section 10 that transfers the generated heat to the reforming section 1. The combustion unit 9 is connected to an off-gas fuel pipe 11 that supplies fuel gas and combustion air and guides off-gas from the anode outlet of the fuel cell 8 to the combustion unit 9 as fuel. Further, a bypass pipe 12 is provided from the reformed gas outlet 1A of the reforming unit 1 to the raw material gas inlet 1B of the reforming unit 1, and a pump 13 and an opening / closing valve 14 are provided on the way.

  The operation and action of the hydrogen generator configured as described above will be described below. The reforming section 1 is filled with a large number of catalyst particles carrying a catalyst for reforming the raw material. For supporting the catalyst, for example, a support such as an iron plate or ceramics can be used. When the vaporized raw material, water vapor, and air are supplied, hydrogen and carbon monoxide are generated. This reaction is usually performed at a high temperature of about 600 ° C. Therefore, the heating means 5 includes the combustion unit 9 that generates heat and the heat exchange unit 10 that transfers the generated heat to the reforming unit 1, and heats the reforming unit 1. In the reforming section 1 that has reached a high temperature, the hydrocarbon reacts with the steam to produce a hydrogen-rich reformed gas. The reforming section 1 needs to be heated to a temperature of 500 to 700 ° C. when a hydrocarbon is used as a raw material. As the reforming catalyst, for example, a Ni-based or Ru-based catalyst is used. In the case of using kerosene or other hydrocarbon-based raw materials, it is known that carbon is likely to precipitate depending on the conditions during reforming, particularly for higher hydrocarbon compounds. The reforming conditions in the reforming unit 1 suppress the carbon deposition while promoting the reaction.

  The desulfurization unit 2 desulfurizes the raw material sent from the raw material supply means 3. The gas containing sulfur deteriorates not only the catalyst deterioration in the reforming section but also the power generation performance of the fuel cell 8. Therefore, the sulfur content of the raw material is removed beforehand by adsorption or the like in the desulfurization section 2.

  The CO transformation unit 6 will be described. The generated reformed gas contains about 8 to 15% of carbon monoxide (CO) generated in addition to unreacted methane, unreacted water vapor, and generated carbon dioxide. For this reason, the reformed gas is provided with a CO conversion section for removing the carbon monoxide by converting it to carbon dioxide and hydrogen. For example, a Fe—Cr-based catalyst, a Cu—Zn-based catalyst, or a Pt catalyst is used in the CO conversion unit 6 and the reaction is performed at about 300 ° C.

  The reaction in the CO conversion unit 6 is CO + H 2 O → CO 2 + H 2, and the steam required for the reforming unit 1 is used as the steam necessary for the reaction. The reformed gas exiting from the CO conversion unit 6 is composed of unreacted methane, excess steam, hydrogen, and carbon dioxide. However, this reformed gas does not completely remove CO, but contains CO although it is less than about 1%. The allowable concentration of CO in the fuel hydrogen supplied to the fuel cell 8 is about 10 ppm, and if it exceeds this, the cell performance is remarkably deteriorated. Therefore, it is necessary to remove the CO component as much as possible before introducing it into the fuel cell 8. . For this reason, the CO removal unit 7 is provided after the reformed gas has its CO concentration lowered to about 1% by the CO conversion unit 6. The CO removal unit 7 supports a catalyst that selectively oxidizes carbon monoxide, and an oxidant such as air is added to remove CO by changing from 2CO + O 2 → 2CO 2 and CO 2. Reduce the concentration to 10 ppm or less. With such a configuration and operation, in a steady state, the raw material gas is reformed to hydrogen, the fuel cell 8 is operated, and power generation is continued.

  In the fuel cell 8, the reformed gas containing a large amount of hydrogen supplied from the CO removing unit 7 flows from the anode inlet, and air is supplied from the cathode inlet. After the power generation reaction, exhaust gas rich in nitrogen is discharged from the cathode outlet, and off-gas with hydrogen remaining is discharged from the anode outlet. During steady operation, this off-gas is guided to the combustion section 9 by the off-gas fuel pipe 11 and burned in the combustion section 9 to contribute to the heating of the reforming section 1 and improve the efficiency of the system. During operation, the on-off valve 14 is opened, the pump 13 is driven, and the raw material gas is caused to flow through the bypass pipe 12, thereby guiding the reformed gas to the reforming unit 1 a plurality of times.

  By allowing the raw material to pass through the reforming unit 1 a plurality of times, the reforming reaction can be repeated. Therefore, the flow rate of the raw material flowing through the reforming unit 1 is increased so that the flow is uniform throughout the catalyst, and the entire catalyst is utilized and overload is prevented. Since the reaction can be made smaller and the reaction can be promoted, an efficient system by improving reforming efficiency and deterioration of the catalyst can be prevented, and a highly reliable hydrogen generator can be obtained.

  Further, since the bypass pipe 12 is connected via an on-off valve 14 which is an electromagnetic valve, the on-off valve 14 is opened during the operation of the conveying means 13 and closed when the conveying means 13 is stopped. Thus, the bypass pipe 12 can be reliably opened during operation and closed when the operation is stopped to prevent the inflow of raw material gas and water vapor into the system. Therefore, when the operation of the bypass pipe 12 is stopped, the high efficiency can be maintained without condensing and collecting water vapor in this pipe. Furthermore, the bypass pipe 12 can be closed, the shortcut of the raw material gas is eliminated, catalyst deterioration of the reforming unit 1, the CO conversion unit 6 and the CO removal unit 7 due to gas movement can be prevented, and durability reliability is improved.

  Further, when increasing or decreasing the amount of hydrogen generated, at least by operating the transport means 13, even if the amount of hydrogen generated increases or decreases, the conversion can be increased and the reaction can be stabilized. That is, when the raw material gas flow rate or the water vapor amount is increased or decreased in accordance with the load to increase or decrease the hydrogen generation amount of the hydrogen generator, the temperature of the reforming unit 1 changes due to the increase or decrease in heating and endothermic amount. , Water vapor evaporation delay, non-uniform mixing with the raw material gas, and partial S / C reduction occurred. Therefore, when increasing or decreasing the amount of generated hydrogen, the gas flow through the reforming unit 1 is increased by operating the conveying means 13 and flowing the gas through the bypass pipe 12 to circulate it so that the flow is uniform throughout the catalyst. By utilizing the entire catalyst and flowing the raw material through the reforming section 1 multiple times, the actual SV value can be reduced and the reaction can be promoted, so that the conversion rate can be stably increased. Deterioration is prevented, and the device has excellent durability and operability and reliability.

  Further, the flow rate of the bypass pipe 12 is increased / decreased according to the increase / decrease of the hydrogen generation amount, and the flow rate of the reforming unit 1 is always kept constant, thereby further stabilizing the change in the raw material gas flow rate. Therefore, the system has a good operation response to the load, and becomes a device with higher operability and reliability. That is, even if the amount of generated hydrogen is changed according to the load, the sum of the raw material gas flowing through the reforming unit 1 and the gas from the bypass pipe 12 is constant, and the flow rate can be always the same. For this reason, there is no delay in evaporation of water vapor caused by changes in flow rate, non-uniform mixing with the raw material gas, or a partial decrease in S / C, and the system has good operational response to the load, operability and reliability. Can improve the performance.

(Embodiment 2)
FIG. 2 is a block diagram of a hydrogen generator according to Embodiment 2 of the present invention. The difference from the first embodiment is that the bypass pipe is thermally insulated by a heat insulating material 15 to constitute a heating means 16 and a temperature detection means 17.

  As a result, the gas exiting from the reforming section 1 contains a large amount of water vapor, and when the heat is radiated by the bypass pipe 12, it liquefies and closes the bypass pipe 12, or the S / C of the gas returning to the reforming section 1 It decreases and inhibits hydrogen reforming reaction. Further, when the heat is radiated by the bypass pipe 12, the temperature of the gas returning to the reforming unit 1 decreases, the energy for raising the reforming unit 1 to increase the temperature in order to maintain the reforming reaction, and the reforming efficiency decreases. By bypassing the bypass pipe with the heat insulating material 15, it is possible to prevent the cooling of the gas coming out of the reforming section 1 and returning to the reforming section 1 through the bypass pipe 12 and keeping the hydrogen reforming efficiency high and stable. In addition, heat dissipation is prevented and the system becomes highly efficient.

  Further, since the bypass pipe 12 is provided with the heating means 16, the gas emitted from the reforming section 1 can be heated, and the bypass pipe 12 radiates and liquefies to close the bypass pipe 12, or the reforming section 1. It is possible to prevent the S / C of the gas returning to from decreasing and inhibiting the hydrogen reforming reaction. For this reason, it is possible to prevent moisture dew condensation of the gas that comes out of the reforming unit 1 and returns to the reforming unit 1 through the bypass pipe 12, and the hydrogen reforming efficiency is kept high and stable, resulting in a highly efficient system.

  Since the bypass pipe 12 includes the heating means 16 and the temperature detection means 17, the temperature of the bypass pipe 12 can be measured by the temperature detection means 17 and the heating means 16 can be operated. For this reason, the bypass pipe 12 is heated too much by the heating means 16 and becomes high temperature, the gas in the bypass pipe 12 is overheated and carbon is precipitated, or the gas in the bypass pipe 12 becomes low temperature due to insufficient heating of the bypass pipe 12. It is possible to prevent the steam in the tank from liquefying and blocking the bypass pipe 12, or the S / C of the gas returning to the reforming unit 1 from being lowered and inhibiting the hydrogen reforming reaction. Therefore, the system becomes a highly efficient system, and the system has a good operation response to the load, and becomes a device with higher efficiency, operability and reliability.

(Embodiment 3)
FIG. 3 is a block diagram of a hydrogen generator according to Embodiment 3 of the present invention. The difference from the first embodiment is that a bypass pipe 18 connecting the gas outlet 6A and the gas inlet 6B of the CO shifter 6 is configured via a conveying means 19 and an on-off valve 20, and a gas outlet of the CO removing unit 7 is used. The bypass pipe 21 connecting the gas inlet 7B and the gas inlet 7B is configured via a conveying means 22 and an on-off valve 23.

  This allows the source gas to pass through each of the CO conversion unit 6 and the CO removal unit 7 a plurality of times to repeatedly perform the conversion reaction and the selective oxidation reaction. For this reason, the flow rate of the raw material gas flowing through the CO conversion unit 6 and the CO removal unit 7 is increased so that the flow is uniform throughout the catalyst to prevent the entire catalyst from being used and overloaded, and the raw material gas is removed from the CO conversion unit 6 and CO. Since it flows to the part 7 multiple times, the actual SV value can be reduced and the reaction can be promoted, thereby promoting the transformation reaction and the selective oxidation reaction to prevent the deterioration of the efficient system and the catalyst due to the improvement of the reforming efficiency. It becomes a highly efficient hydrogen generator.

  The bypass pipes 18 and 21 are connected to the bypass pipes 18 and 21 through on-off valves 20 and 23, which are electromagnetic valves, so that the on-off valves 20 and 23 are opened during the operation of the transfer means 19 and 22, and the transfer means 19 and 20 are used. Since the bypass pipes 18 and 21 are closed during operation, the bypass pipes 18 and 21 can be reliably opened during operation, and can be closed during operation stop to prevent inflow of raw material gas and water vapor into the system. For this reason, when the operation of the bypass pipes 18 and 21 is stopped, the high-efficiency can be maintained without condensing and accumulating water vapor in the pipes. Further, the bypass pipes 18 and 21 can be closed, the raw material gas shortcut is eliminated, catalyst deterioration of the reforming unit 1, the CO conversion unit 6 and the CO removal unit 7 due to gas movement can be prevented, and durability reliability is improved. .

  Then, according to the increase or decrease of the amount of hydrogen generated, the flow rate of flowing through the bypass pipes 18 and 21 is increased or decreased so that the flow rate of flowing through the CO conversion unit 6 and the CO removal unit 7 is always a constant amount. The system can be stabilized against changes, and the system has a better response to the load, and is more operable and reliable. That is, even if the amount of generated hydrogen is changed according to the load, the sum of the raw material gas flowing through the CO conversion unit 6 and the CO removal unit 7 and the gas from the bypass is constant, and the flow rate can always be the same. For this reason, there is no delay in evaporation of water vapor caused by changes in flow rate, non-uniform mixing with the raw material gas, or a partial decrease in S / C, and the system has good operational response to the load, operability and reliability. Can improve the performance.

(Embodiment 4)
FIG. 4 is a block diagram of a hydrogen generator according to Embodiment 4 of the present invention. The difference from the first embodiment is that each of the bypass pipes 18 and 21 is thermally insulated by heat insulating materials 24 and 25, and heating means 26 and 27 and temperature detecting means 28 and 29 are provided. The gas exiting from the CO conversion unit 6 and the CO removal unit 7 contains a large amount of water vapor, and when the heat is radiated by the bypass pipes 18 and 21, the gas is liquefied and closes the bypass pipes 18 and 21, or the CO conversion unit 6 or The S / C of the gas that returns to the CO removal unit 21 is reduced, thereby inhibiting the hydrogen reforming reaction. Further, when the heat is radiated through the bypass pipes 18 and 21, the temperature of the gas returning to the CO conversion unit 6 or the CO removal unit 21 is lowered, and the energy that makes the CO conversion unit 6 or the CO removal unit 21 high temperature in order to maintain the reforming reaction. As a result, metamorphic efficiency and selective oxidation efficiency decrease. By bypassing the bypass pipes 18, 21, it is possible to prevent cooling of the gas that exits the CO conversion unit 6 or the CO removal unit 21, passes through the bypass pipes 18, 21, and returns to the re-CO conversion unit 6 or the CO removal unit 21. The hydrogen generation efficiency is high and stable, and heat dissipation is prevented, resulting in a highly efficient system.

  The bypass pipes 18 and 21 are provided with heating means 26 and 27, so that the gas emitted from the CO conversion section 6 or the CO removal section 7 can be heated, and the bypass pipes 18 and 21 dissipate heat and liquefy it. It is possible to prevent the S / C of the gas returning to the CO conversion unit 6 or the CO removal unit 7 from being lowered and inhibiting the hydrogen reforming reaction. For this reason, it is possible to prevent moisture condensation of the gas that comes out of the CO conversion unit 6 or the CO removal unit 7 and returns to the CO conversion unit 6 or the CO removal unit 7 again through the bypass pipes 18 and 21, and the hydrogen generation efficiency is highly stable. Maintaining a highly efficient system.

  The bypass pipes 18 and 21 are configured with heating means 26 and 27 and temperature detection means 28 and 29, whereby the temperature of the bypass pipes 18 and 21 is measured by the temperature detection means 28 and 29, and the heating means 26, 27 can be operated to change the heating amount. For this reason, the bypass pipes 18 and 21 are heated too much by the heating means 26 and 27 and become high temperature, the gas in the bypass pipes 18 and 21 is overheated and carbon is deposited, or the bypass pipes 18 and 21 are not heated enough. The water vapor in the gas in the bypass pipes 18 and 21 is liquefied to close the bypass pipe, or the S / C of the gas returning to the CO conversion section 6 or the CO removal section 7 is lowered to inhibit the hydrogen reforming reaction. This can be prevented, and the hydrogen production rate can be kept high and stable, resulting in a highly efficient system.

  In the hydrogen generator according to the present invention, since the raw material passes through the reforming section a plurality of times, the raw material is brought into contact with the entire catalyst, so that the entire catalyst is effectively utilized and the SV value is substantially reduced. The reaction can be promoted, and it can be applied as a hydrogen supplier excellent in durability and reliability for a hydrogen-based fuel cell such as a solid polymer fuel cell.

Block diagram of a hydrogen generator in Embodiment 1 of the present invention Block diagram of a hydrogen generator in Embodiment 2 of the present invention Block diagram of a hydrogen generator in Embodiment 3 of the present invention Block diagram of a hydrogen generator in Embodiment 4 of the present invention Block diagram showing a conventional hydrogen generator Sectional view showing a reforming reactor of a conventional hydrogen generator

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reforming part 6 CO conversion part 7 CO removal part 8 Fuel cell 12 Bypass pipe 13 Conveying means 14 On-off valve

Claims (13)

A reforming section having heating means to supply the raw material and water and reforming the raw material; an inlet section provided in the reforming section and an outlet section for flowing out after the raw material is reformed; A hydrogen generator comprising: a CO conversion unit and a CO removal unit that are sequentially connected to the reforming unit; a bypass pipe that connects the outlet unit and the inlet unit; and a conveying means that is provided in the bypass pipe. 2. The hydrogen generator according to claim 1, wherein an electromagnetic valve or a check valve is disposed in the bypass pipe, and the electromagnetic valve or the check valve is opened when the conveying means is in operation and closed when the conveying means is stopped. The hydrogen generator according to claim 1 or 2, wherein at least the transfer means is operated when increasing or decreasing the amount of generated hydrogen. The hydrogen generator according to claim 1, 2, or 3, wherein the flow rate flowing through the bypass pipe is increased or decreased in accordance with the increase or decrease of the hydrogen generation amount, and the flow rate flowing through the reforming unit is always constant. The hydrogen generator according to claim 1, wherein the bypass pipe is insulated. The hydrogen generator according to any one of claims 1 to 5, wherein heating means is provided in the bypass pipe. The hydrogen generator according to claim 6, wherein temperature detection means is provided in the bypass pipe. A reforming unit having heating means to supply raw material and water to reform the raw material, a CO conversion unit and a CO removal unit sequentially connected to the reforming unit, the CO conversion unit, and the CO removal unit Hydrogen generation provided with at least one inlet portion into which the reformed raw material flows and an outlet portion through which the reformed raw material flows, a bypass pipe connecting the inlet portion and the outlet portion, and a conveying means provided in the bypass pipe vessel. The hydrogen generator according to claim 8, wherein an electromagnetic valve or a check valve is disposed in the bypass pipe, and the electromagnetic valve or the check valve is opened when the conveying unit is in operation and closed when the conveying unit is stopped. The hydrogen generator according to claim 8 or 9, wherein the flow rate flowing through the bypass pipe is increased or decreased in accordance with the increase or decrease of the hydrogen generation amount, and the flow rate flowing through the CO conversion unit or the CO removal unit is always constant. The hydrogen generator according to claim 8, 9 or 10, wherein the bypass pipe is insulated. The hydrogen generator according to any one of claims 8 to 11, wherein heating means is provided in the bypass pipe. The hydrogen generator according to claim 12, wherein a temperature detection means is provided in the bypass pipe.

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