JP2014172779A - Hydrogen generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen generator capable of generating a specified volume of hydrogen even if the caloric value within a raw ingredient gas has varied due to the migration of an oxidant into the raw ingredient gas.SOLUTION: The provided hydrogen generator includes: a hydrogenating desulfurizer for removing a sulfur component within a raw ingredient gas; a hydrogenating temperature detector for detecting the temperature of the hydrogenating desulfurizer; a raw ingredient feeder for feeding the raw ingredient gas into the hydrogenating desulfurizer; a hydrogen-containing gas feeder for feeding a hydrogen-containing gas into the hydrogenating desulfurizer; and a controller for controlling at least the raw ingredient feeder, whereas, in a case where the temperature detected by the hydrogenating temperature detector has exceeded a first temperature threshold set in advance, the flow rate of the raw ingredient gas fed into the hydrogenating desulfurizer is controlled to become greater than that of a case where the temperature detected by the hydrogenating temperature detector is equal to or lower than the first temperature threshold.

Description

  The present invention relates to a hydrogen generator equipped with a hydrodesulfurizer.

  Development of a fuel cell capable of high-efficiency power generation even with a small device is being developed as a power generator for a distributed energy supply source. Hydrogen gas used as fuel for fuel cell power generation has not been developed as a general infrastructure. Therefore, when used as a distributed device, for example, a configuration may be adopted in which a hydrogen generation device for generating a hydrogen-containing gas by reacting a raw material obtained from an existing fossil raw material infrastructure such as city gas and LPG with a steam reforming reaction is used. Many. The existing fossil raw material infrastructure such as city gas and LPG contains sulfur as an odorant or as a component derived from the raw material, but the sulfur needs to be desulfurized in order to reduce the reforming performance and the like.

  An example of the desulfurization method is a hydrodesulfurization method in which hydrogen is added. Since the hydrodesulfurization method uses a chemical reaction, the adsorption capacity of sulfur is large, and it is possible to desulfurize without replacing the catalyst for a long time or with a small apparatus (for example, Patent Document 1).

  On the other hand, raw materials such as city gas and LPG may be temporarily mixed with oxygen due to the infrastructure configuration. Therefore, a preliminary reforming method of a process gas containing oxygen, such as natural gas, peak shaving gas, LPG, etc. has been proposed (for example, Patent Document 2).

JP-A-7-57756 Japanese Patent Laid-Open No. 2001-80907

  As described above, when oxygen is mixed in the raw material, even if the same flow rate is supplied as the raw material, the amount of heat or hydrocarbon decreases, so the amount of hydrogen produced by the reforming reaction in the reformer is reduced. The problem which will fall arises.

  The present invention provides a hydrogen generator capable of generating a predetermined amount of hydrogen even if the amount of heat in the source gas changes due to the oxidant entering the source gas.

  In order to solve the above problems, a hydrogen generator of the present invention includes a hydrodesulfurizer that removes sulfur components in a raw material gas, a hydrogenation temperature detector that detects the temperature of the hydrodesulfurizer, and hydrodesulfurization. A raw material supply device that supplies the raw material gas to the reactor, a hydrogen-containing gas supply device that supplies the hydrogen-containing gas to the hydrodesulfurization device, and a controller that controls at least the raw material supply device. When the temperature detected by the detector exceeds a preset first temperature threshold, the flow rate of the raw material gas supplied to the hydrodesulfurizer is below the first temperature threshold. It is set as the structure controlled so that it may become larger than the flow volume of the source gas supplied.

In the hydrogen generator of the present invention, it is detected that the oxidant such as oxygen is mixed in the raw material when the temperature detected by the hydrogenation temperature detector exceeds a preset first temperature threshold, and the flow rate of the raw material gas Is controlled to be larger, so that a hydrogen generator capable of maintaining the hydrogen generation amount can be provided.

Schematic of the hydrogen generator in Embodiment 1 or 2 of the present invention Schematic of the hydrogen generator in Embodiment 3 of the present invention Schematic of the hydrogen generator in Embodiment 4 of the present invention Schematic of the hydrogen generator in Embodiment 5 of the present invention

  The first invention is a hydrodesulfurizer for removing sulfur components in a raw material gas, a hydrogenated temperature detector for detecting the temperature of the hydrodesulfurizer, and supplying the raw material gas to the hydrodesulfurizer A raw material supply device, a hydrogen-containing gas supply device for supplying a hydrogen-containing gas to the hydrodesulfurization device, and a controller for controlling at least the raw material supply device, wherein the controller is the hydrogenation temperature detector. When the detected temperature exceeds a preset first temperature threshold value, the temperature detected by the hydrogenation temperature detector is supplied to the hydrodesulfurizer compared to the case where the temperature detected is not more than the first temperature threshold value. A hydrogen generator that controls the flow rate of the source gas to be increased.

  With this configuration, it is determined that oxygen has entered when the temperature of the hydrodesulfurizer exceeds the threshold, and by increasing the raw material gas flow rate, the amount of heat, that is, the amount of hydrocarbons reduced by oxygen entering the raw material is reduced. The amount can be increased and maintained up to a predetermined amount, and as a result, the amount of hydrogen can be maintained.

  In a second aspect of the invention, particularly in the first aspect of the invention, the controller is configured such that when the temperature detected by the hydrogenation temperature detector exceeds a preset first temperature threshold, the first time per unit time. When the temperature range is increased, the flow rate of the source gas is increased by a first rate, and when the second temperature range is increased per unit time, which is greater than the first temperature range, the flow rate of the source gas is increased from the first rate. A large second rate increase hydrogen generator.

  This configuration makes it possible to determine the amount of oxygen that has flowed in due to the difference in temperature rise of the hydrodesulfurizer, and to determine the flow rate of the raw material to be increased from the reduced heat amount, that is, the flow rate of hydrocarbons as the raw material gas. Therefore, it is possible to maintain the production of a predetermined amount of hydrogen regardless of the amount of oxygen that flows in.

  In a third aspect of the invention, particularly in the first or second aspect of the invention, the hydrogen-containing gas supplier reforms the raw material gas supplied from the hydrodesulfurizer by a reforming reaction to generate a hydrogen-containing gas. A hydrogen generator comprising a reformer and configured to supply a part of the hydrogen-containing gas discharged from the reformer to the hydrodesulfurizer.

  With this configuration, it is possible to efficiently perform a hydrodesulfurization reaction using hydrogen generated in the reformer and remove sulfur.

  In a fourth aspect of the invention, particularly in the third aspect of the invention, the apparatus includes a water supply device for supplying water to the reformer, and the controller detects a temperature detected by the hydrogenation temperature detector in advance. When the temperature exceeds the first temperature threshold, the flow rate of the water supplied to the reformer is controlled to be larger than when the temperature detected by the hydrogenation temperature detector is equal to or lower than the first temperature threshold. This is a hydrogen generator.

  With this configuration, the amount of water required for the reforming reaction can be increased in accordance with the increase in the raw material gas, so that the proportion of the raw material gas in the reformer can be kept constant and stable hydrogen production can be achieved.

  According to a fifth aspect of the invention, in particular, in the third or fourth aspect of the invention, a reformed air supply device for supplying air to the reformer is provided, and the controller has a temperature detected by the hydrogenation temperature detector. The flow rate of the air supplied to the reformer is higher than the case where the temperature detected by the hydrogenation temperature detector is equal to or lower than the first temperature threshold when a preset first temperature threshold is exceeded. This is a hydrogen generator that is controlled to be large.

  With this configuration, the amount of air required for the reforming reaction can be increased in accordance with the increase in the raw material gas, so that the raw material gas ratio in the reformer can be kept constant and stable hydrogen production can be achieved.

  In a sixth invention, particularly in the third to fifth inventions, a combustor that burns at least one of the source gas and the hydrogen-containing gas and combustion air and heats the reformer, and the combustion A combustion air supplier for supplying air to the vessel, wherein the controller detects the hydrogenation temperature when the temperature detected by the hydrogenation temperature detector exceeds a preset first temperature threshold. And a hydrogen generator that controls the flow rate of the combustion air supplied to the combustor to be higher than that when the temperature detected by the combustor is equal to or lower than the first temperature threshold.

  With this configuration, the amount of heat necessary for the reforming reaction can be increased in accordance with the increase in the raw material gas, and combustion can be stably maintained, so that stable hydrogen generation can be achieved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic diagram showing the configuration of the hydrogen generator in Embodiment 1 of the present invention.

  The hydrogen generator includes a hydrodesulfurizer 1 that removes sulfur contained in natural gas as a raw material gas, hydrocarbon components such as LPG, alcohols such as methanol, naphtha components, and the like.

  In addition, a hydrodesulfurization temperature detector 2 for detecting the temperature of the hydrodesulfurizer, a raw material supplier 3 for supplying a raw material gas to the hydrodesulfurizer, and a hydrogen gas contained in the raw material gas in order to function hydrodesulfurization It was set as the structure provided with the hydrogen containing gas supply device 4 which adds and supplies gas, and the controller 5 which controls the raw material supply device 3 at least. The hydrodesulfurizer 1 used was a previously reduced Cu-Zn hydrodesulfurization catalyst.

  Next, the operation method of the hydrogen generator in the present invention will be described.

  In the hydrogen generator, the raw material is supplied from the raw material supplier 3 by the controller 5, while the hydrogen-containing gas is supplied from the hydrogen-containing gas supplier 4. Here, the hydrodesulfurizer 1 is designed so that the temperature detected by the hydrodesulfurization temperature detector 2 is about 250 ° C. This is based on the fact that the hydrodesulfurization catalyst used in the present embodiment is desirably used in a temperature range of 200 ° C to 300 ° C. Further, the hydrogen-containing gas supply unit 4 was controlled so that the hydrogen concentration in the raw material gas supplied to the hydrodesulfurization unit 1 was about 5%. The flow rate of the raw material gas supplied from the raw material supplier 3 is preferably determined according to the required amount of hydrogen, and a method of controlling using a flow meter was used.

  Next, characteristic operations in the first embodiment will be described.

In this embodiment, a method of supplying a raw material gas using a flow meter is employed. However, when the composition of the raw material gas changes, a flow rate actually flowing (hereinafter referred to as an indicated flow rate) ( Hereinafter, the actual flow rate) can change. For example, air may be added to the raw material gas to adjust the calorific value of the raw material gas, such as peak shaving gas. When the composition of the raw material gas changes due to air mixing, the actual flow rate with respect to the indicated flow rate decreases, and the predetermined flow The amount of hydrogen cannot be generated.

  On the other hand, the hydrodesulfurizer 1 of the hydrogen generator is operated so that the temperature detected by the hydrodesulfurization temperature detector 2 is about 250 ° C. Here, when air is mixed in the raw material gas, for example, when a reduced hydrodesulfurization catalyst is used, heat is generated by an oxidation reaction. Alternatively, it generates heat by a combustion reaction with the raw material gas or the hydrogen-containing gas.

  Therefore, in the present embodiment, when the temperature detected by the hydrodesulfurization temperature detector 2 exceeds a preset first temperature threshold (280 ° C. in the present embodiment), the controller 5 Control is performed to increase the flow rate of the raw material gas supplied to the desulfurizer 1. As a result, the amount of heat of the raw material gas produced by mixing air, that is, the amount of hydrocarbons can be increased and maintained to a predetermined amount, and the amount of hydrogen can be maintained.

  For example, if oxygen is mixed into a 100% methane raw material gas and becomes a mixed gas of 97% methane and 3% oxygen, when controlling using a mass flow controller, the flow rate of methane alone is the raw material flow rate due to its conversion factor. This is approximately 98% of the flow rate indicated as the gas flow rate. That is, only about 98% of the assumed raw material flow rate contributes to hydrogen generation. At this time, the temperature detected by the hydrodesulfurization temperature detector rises by about 30 degrees due to the mixed oxygen. A predetermined amount of hydrogen can be maintained by increasing the flow rate of the source gas (increase of about 2% in the present embodiment) with this temperature rise.

(Embodiment 2)
A hydrogen generator according to Embodiment 2 of the present invention will be described. Since the second embodiment has the configuration shown in FIG. 1 as in the first embodiment, a detailed description thereof will be omitted. Next, a characteristic operation of the second embodiment which is different from that of the first embodiment will be described.

  In the present embodiment, when the temperature detected by the hydrodesulfurization temperature detector 2 exceeds a preset first temperature range value (280 ° C. in the present embodiment), a unit time (this embodiment) In the embodiment, when the first temperature range (10 ° C. in this embodiment) increases per 10 seconds, the flow rate of the source gas is increased by the first ratio (2% in this embodiment), and per unit time When the second temperature range larger than the first temperature range (in this embodiment, 20 ° C.) increases, the controller 5 increases the flow rate of the source gas to a second rate (5 in this embodiment) larger than the first rate. %) Is increased.

  Thereby, according to the ratio of the mixed air, the flow volume of source gas can be increased and the production amount of hydrogen can be maintained as a result.

(Embodiment 3)
A hydrogen generator according to Embodiment 3 of the present invention will be described. FIG. 2 is a schematic diagram showing the configuration of the hydrogen generator in Embodiment 3 of the present invention. In addition to the configuration of the first embodiment, the raw material gas supplied from the hydrodesulfurizer 1 is reformed by a reforming reaction to generate a hydrogen-containing gas, which is discharged from the reformer 6. A part of the hydrogen-containing gas was supplied to the hydrodesulfurizer 1. The reformer 6 was a Ru catalyst that causes a steam reforming reaction to proceed as a reforming catalyst, and was used at about 600 ° C. Further, a water supply device 7 for supplying water to the reformer 6 was provided.

Next, a characteristic operation in the third embodiment will be described. When the temperature detected by the hydrodesulfurization temperature detector 2 exceeds a preset first temperature threshold (280 ° C. in the present embodiment), the controller 5 is supplied to the hydrodesulfurizer 1. Control to increase water flow. Similarly to the second embodiment, the rate of increase in water may be determined from the temperature rise width per unit time.
As a result, the amount of heat of the raw material gas produced by mixing air, that is, the amount of hydrocarbons can be increased and maintained to a predetermined amount, and the amount of hydrogen can be maintained. As a control method for increasing the flow rate of water, the flow rate of water itself may be increased, or the S / C that represents the ratio of the water flow rate to the hydrocarbon flow rate that is the raw material gas is kept constant. The flow rate of water may be increased in proportion to the increase.

  With this configuration, the amount of water required for the reforming reaction can be increased in accordance with the increase in the raw material gas, so that the proportion of the raw material gas in the reformer can be kept constant and stable hydrogen production can be achieved.

(Embodiment 4)
A hydrogen generator according to Embodiment 4 of the present invention will be described. FIG. 3 is a schematic diagram showing the configuration of the hydrogen generator in Embodiment 4 of the present invention. In addition to the configuration of the first embodiment, a reformer 6 for reforming the raw material gas supplied from the hydrodesulfurizer 1 by a reforming reaction to generate a hydrogen-containing gas is provided. The reformer 6 was a Pt catalyst that allowed a partial oxidation reforming reaction to proceed as a reforming catalyst, and was used at about 650 ° C. Further, a reformed air supply unit 8 for supplying air to the reformer 6 is provided. Note that, similarly to the third embodiment, the water supply device 7 may be provided simultaneously with the reformed air supply device 8, and in this case, the reforming reaction proceeds as an autothermal reaction. In this embodiment, a method that does not use the water supplier 7 is adopted.

  Next, a characteristic operation in the fourth embodiment will be described. When the temperature detected by the hydrodesulfurization temperature detector 2 exceeds a preset first temperature threshold (280 ° C. in the present embodiment), the controller 5 is supplied to the hydrodesulfurizer 1. Control to increase water flow. Similarly to the second embodiment, the rate of increase in water may be determined from the temperature rise width per unit time. As a result, the amount of heat of the raw material gas produced by mixing air, that is, the amount of hydrocarbons can be increased and maintained to a predetermined amount, and the amount of hydrogen can be maintained. As a control method for increasing the flow rate of air, the flow rate of air itself may be increased, or by keeping O2 / C representing the ratio of the air flow rate to the hydrocarbon flow rate that is the source gas constant. The air flow rate may be increased in proportion to the increase.

  With this configuration, the amount of air required for the reforming reaction can be increased in accordance with the increase in the raw material gas, so that the raw material gas ratio in the reformer can be kept constant and stable hydrogen production can be achieved.

(Embodiment 5)
A hydrogen generator according to Embodiment 5 of the present invention will be described. FIG. 4 is a schematic diagram showing the configuration of the hydrogen generator in Embodiment 5 of the present invention. In addition to the configurations of the first to fourth embodiments, at least one of the raw material gas and the hydrogen-containing gas and combustion air are combusted, and at least the reformer 6 is heated, and the combustor 9 is supplied with air. It was set as the structure provided with the combustion air supply device 10 to supply. In addition, it is good also as a structure provided with the reformed air supply device 8 which supplies air to the reformer 6 similarly to Embodiment 4. FIG.

  Next, characteristic operations in the fifth embodiment will be described. When the temperature detected by the hydrodesulfurization temperature detector 2 exceeds a preset first temperature threshold value (280 ° C. in the present embodiment), the controller 5 is used for combustion supplied to the combustor 9. Control to increase air flow. Similarly to the second embodiment, the rate of increase in the combustion air may be determined from the temperature rise per unit time.

  As a result, the flow rate of the combustion air can be increased in accordance with the increase of the raw material gas, and an appropriate air ratio can be maintained, so that it is possible to suppress misfire and generation of unburned gas and to stabilize combustion. Since it can be maintained, stable hydrogen production becomes possible.

  The present invention measures the temperature of the hydrodesulfurizer to determine a decrease in the calorific value of the raw material gas, that is, the hydrocarbon flow rate due to air mixing in the raw material gas, and increases the flow rate of the raw material gas by increasing the flow rate of the raw material gas. Is a dispersion type that generates hydrogen by reforming a raw material gas that contains sulfur and needs to be desulfurized and can be mixed with air. It is particularly useful for a fuel cell power generation system such as a solid polymer type or a solid oxide type.

DESCRIPTION OF SYMBOLS 1 Hydrodesulfurizer 2 Hydrodesulfurization temperature detector 3 Raw material supply device 4 Hydrogen-containing gas supply device 5 Controller 6 Reformer 7 Water supply device 8 Reformed air supply device 9 Combustor 10 Combustion air supply device

Claims (6)

A hydrodesulfurizer for removing sulfur components in the raw material gas;
A hydrogenation temperature detector for detecting the temperature of the hydrodesulfurizer;
A raw material supplier for supplying the raw material gas to the hydrodesulfurizer;
A hydrogen-containing gas supplier for supplying a hydrogen-containing gas to the hydrodesulfurizer;
A controller for controlling at least the raw material supplier;
With
The controller is configured such that when the temperature detected by the hydrogenation temperature detector exceeds a preset first temperature threshold, the temperature detected by the hydrogenation temperature detector is less than or equal to the first temperature threshold. The hydrogen generator which controls so that the flow volume of the said raw material gas supplied to the said hydrodesulfurizer may become larger than the case of.   The controller controls the flow rate of the source gas when the temperature detected by the hydrogenation temperature detector exceeds a preset first temperature threshold and the first temperature range increases per unit time. The flow rate of the source gas is increased by a second rate greater than the first rate when the second rate of increase is greater than the first temperature range per unit time. The hydrogen generator described. The hydrogen-containing gas supplier includes a reformer that reforms the raw material gas supplied from the hydrodesulfurizer by a reforming reaction to generate a hydrogen-containing gas.
The hydrogen generator according to claim 1 or 2, wherein a part of the hydrogen-containing gas discharged from the reformer is configured to be supplied to the hydrodesulfurizer. A water supply for supplying water to the reformer,
The controller is configured such that when the temperature detected by the hydrogenation temperature detector exceeds a preset first temperature threshold, the temperature detected by the hydrogenation temperature detector is less than or equal to the first temperature threshold. The hydrogen generation apparatus according to claim 3, wherein the flow rate of the water supplied to the reformer is controlled to be larger than in the case of. A reforming air supplier for supplying air to the reformer;
The controller is configured such that when the temperature detected by the hydrogenation temperature detector exceeds a preset first temperature threshold, the temperature detected by the hydrogenation temperature detector is less than or equal to the first temperature threshold. The hydrogen generator according to claim 3 or 4 which controls so that the flow volume of said air supplied to said reformer may become larger than the case of. A combustor that burns at least one of the source gas and the hydrogen-containing gas and combustion air and heats the reformer;
A combustion air supply for supplying air to the combustor,
The controller is configured such that when the temperature detected by the hydrogenation temperature detector exceeds a preset first temperature threshold, the temperature detected by the hydrogenation temperature detector is less than or equal to the first temperature threshold. The hydrogen generation device according to any one of claims 3 to 5, wherein the control is performed so that the flow rate of the combustion air supplied to the combustor is larger than in the case of the above.