JP2005206413A - Hydrogen generating apparatus and fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen generating apparatus which realizes a high efficiency and a stable operation; and a fuel cell power generation system using the same. <P>SOLUTION: The hydrogen generating apparatus is equipped with an ambient temperature detection means for detecting the ambient temperature of the apparatus. In the apparatus, any of the temperature of a reforming catalyst body packed in a reforming part, the temperature of the downstream of the reforming catalyst body, the temperature of a carbon monoxide removal catalyst body packed in a carbon monoxide removal part, and the temperature of a reformed gas at the upstream and downstream sides of the carbon monoxide removal catalyst body is regarded as a catalyst temperature. Based on the ambient temperature acquired by the ambient temperature detection means, at least either of the catalyst temperature and the ratio of water to an organic-compound-containing raw material is changed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hydrogen generator that reforms a hydrocarbon-based fuel to generate hydrogen gas, and a fuel cell system using the hydrogen generator.

  In addition to high power generation efficiency, fuel cell power generators can effectively use the heat generated during power generation, and are expected to be applied to household cogeneration.

  In home use, it is desirable to operate the fuel cell power generator at a relatively low temperature from the viewpoint of responding to frequent start / stop of the apparatus, durability of the apparatus, and cost reduction. Therefore, development of a polymer electrolyte fuel cell using a polymer electrolyte membrane as a power generation unit has been advanced.

  Many fuel cells generate electricity using hydrogen as fuel. At present, the hydrogen gas infrastructure that serves as the fuel is not in place, so at the place where the power generation equipment is installed, organic gas composed of at least carbon and hydrogen such as natural gas, hydrocarbon components such as LPG, alcohol such as methanol, or naphtha components A hydrogen generator for generating a reformed gas containing hydrogen by reacting a raw material containing a compound with water is used in combination. In addition to hydrogen, carbon dioxide and carbon monoxide (hereinafter referred to as CO) derived from the raw materials are included as subcomponents in the generated reformed gas. Since the polymer electrolyte fuel cell currently under development operates at a low temperature of 100 ° C. or lower, CO contained in the reformed gas is reduced as much as possible (generally 10% to maintain the activity of the battery electrode catalyst). ~ 50 ppm or less). Therefore, in the hydrogen generator, a reforming unit that generates hydrogen gas, a shift unit that shifts CO and water in the hydrogen gas, and a CO removal unit that includes a purification unit that oxidizes CO are used in combination. The

  The reforming section, the shift section, and the CO removal section are filled with a catalyst body suitable for each reaction, and are controlled to a predetermined temperature at which the apparatus efficiency is highest and operates stably.

  By the way, in the operation of the hydrogen generator, when the ambient temperature rises or falls, the temperature of the raw material and water to be supplied, the amount of heat released from the machine, and the like change, so that the optimum control conditions change.

As a technique for coping with a change in the ambient temperature of the hydrogen generator, a technique for preventing freezing when the ambient temperature becomes 0 ° C. or lower has been proposed (see, for example, Patent Document 1).
JP 2000-313602 A

  However, when the installation area is a cold region or a warm region, or the region where the temperature changes drastically depending on the season, the ambient temperature of the device changes greatly, and the heat radiation conditions vary significantly. In this case, even if the temperatures of the reforming unit and the CO removing unit are controlled to be the same, the substantial catalyst temperature changes. For this reason, when the ambient temperature is high, the heating amount increases more than necessary and the apparatus efficiency decreases, and when the ambient temperature is low, the actual catalyst temperature decreases too much and the hydrogen generation amount decreases. , CO may not be sufficiently removed. The substantial catalyst temperature is the average temperature of the entire catalyst with respect to the catalyst temperature measured by the catalyst temperature detecting means.

  The present invention solves the above-described problems related to the conventional hydrogen generator, and an object thereof is to provide a hydrogen generator and a fuel cell power generation system that realize high efficiency and stable operation.

The first aspect of the present invention comprises a reforming unit that reacts a raw material containing an organic compound with water to generate a reformed gas containing at least hydrogen and carbon monoxide;
A carbon monoxide removal unit having at least a transformation unit that reduces the carbon monoxide in the reformed gas generated by the reforming unit by a shift reaction;
The temperature of the reforming catalyst body charged in the reforming section, the temperature downstream of the reforming catalyst body, the temperature of the carbon monoxide removal catalyst body charged in the carbon monoxide removal section, or the carbon monoxide removal. A catalyst temperature detecting means for detecting either the upstream side or downstream side reformed gas temperature of the catalyst body;
Catalyst temperature control means for controlling the detected temperature to be a predetermined catalyst temperature;
An ambient temperature detecting means for detecting the ambient temperature of the hydrogen generator, or an ambient temperature predicting means for predicting the ambient temperature,
The hydrogen generator is characterized in that the catalyst temperature or the ratio of water to the raw material is changed based on the ambient temperature obtained from the ambient temperature detecting means or the ambient temperature predicting means.

  The second aspect of the present invention is the hydrogen generator characterized in that when the ambient temperature is lowered, the catalyst temperature of at least one of the reforming unit and the carbon monoxide removing unit is increased.

  The third aspect of the present invention is the hydrogen generator characterized by increasing the ratio of water to the raw material supplied to the reforming section when the ambient temperature is lowered.

  The fourth aspect of the present invention is a carbon monoxide removing unit that selectively oxidizes carbon monoxide in the reformed gas and an oxidant gas supply unit, an oxidant gas supplied from the oxidant gas supply unit, And a purifying unit for reducing carbon monoxide, wherein the amount of oxidant gas supplied from the oxidant gas supply unit is increased when the ambient temperature is lowered.

  The fifth aspect of the present invention includes a storage device that records the relationship between the location of the hydrogen generator or the local date and temperature, and the temperature data, and the ambient temperature predicting means includes the temperature stored in the storage device. This is a hydrogen generator characterized by prediction based on data.

  According to a sixth aspect of the present invention, there is provided a fuel cell comprising the above hydrogen generator, and a fuel cell that generates electricity using an oxygen-containing oxidant gas and a hydrogen-containing fuel gas supplied from the hydrogen generator. System.

  The seventh aspect of the present invention is a fuel cell comprising a cooling means for controlling the temperature of the fuel cell according to the flow rate of the cooling medium while circulating the cooling medium, and when the ratio of water to the reforming section is increased, In the fuel cell system, when the temperature of the fuel cell is raised by the cooling means and the ratio of water to the reforming portion is reduced, the temperature of the fuel cell is lowered by the cooling means.

  According to the present invention, each catalyst body is controlled to an optimum temperature according to a change in the ambient temperature around the hydrogen generator, and can be operated stably while maintaining high power generation efficiency under conditions where the temperature fluctuation due to the season is large. Can do.

  That is, according to the present invention, it is possible to provide a fuel cell power generator that maintains high power generation efficiency in accordance with changes in temperature.

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

(Embodiment 1)
First, the configuration of the hydrogen generator in the present embodiment will be described with reference to FIG. FIG. 1 is a schematic diagram showing a configuration of a fuel cell power generation system including a hydrogen generator in the present embodiment.

  In FIG. 1, the reforming unit 1 is a reactor filled with a reforming catalyst, and the heating unit 2 is a combustion burner that heats the reforming unit 1. Further, a raw material supply unit 3 that supplies the raw material to the reforming unit 1 and a water supply unit 4 that supplies water to the reforming unit 1 are installed. On the downstream side of the reforming unit 1 is a shift unit 5 which is one of the carbon monoxide removal units of the present invention, and on the downstream side of the shift unit 5, an oxidant gas containing oxygen (air in the present embodiment). An air supply unit 6 that is an oxidant gas supply unit of the present invention, a purification unit 7 that is one of the carbon monoxide removal units of the present invention, and a fuel cell power generation unit 8 on the downstream side of the purification unit 7 Is installed. The temperature of the fuel cell power generation unit 8 is controlled by the cooling means 102 that adjusts the flow rate of the cooling medium flowing in the fuel cell. Further, the offgas containing methane and hydrogen after passing through the fuel cell power generation unit 8 is supplied to the heating unit 2 and used for heating the reforming unit 1. The combustion gas supply unit 9 supplies combustion gas to the heating unit 2 when the hydrogen generator is started up or when the heating amount for heating the reforming unit 1 is insufficient.

  In addition, an ambient temperature detector 10 for measuring the ambient temperature of the hydrogen generator is provided as the ambient temperature measuring means of the present invention. In addition, although the installation location of the ambient temperature detector 10 is not particularly limited, an ambient temperature or a location where a change in temperature linked to the ambient temperature can be detected around the hydrogen generator is preferable. An example of such a place is an outside air intake.

  Further, the reforming section 1 is filled with a reforming catalyst body supporting Ru on alumina, and the reforming section thermocouple 101 is installed as the catalyst temperature detecting means of the present invention for detecting the temperature of the reforming catalyst body. It is. In addition, it is preferable to install the said reforming part thermocouple in the location which can measure the temperature downstream of the reforming catalyst body itself or the said reforming catalyst body as mentioned above.

  Further, as shown in FIG. 2, the inside of the shift unit 5 is filled with a copper zinc-based catalyst as the shift catalyst body 12 which is one of the carbon monoxide removal catalyst bodies of the present invention, and the upstream side and the downstream side of the shift catalyst body 12. On the side, a modified upstream thermocouple 13 and a modified downstream thermocouple 14 for detecting the temperature are installed. Further, a heat exchanging section 16 for controlling the reformed gas temperature introduced into the shift catalyst body 12 is installed at the shift section inlet 11.

  Further, as shown in FIG. 3, the inside of the purification unit 7 is filled with a catalyst in which Pt is supported on alumina as the purification catalyst body 22, and is upstream of the purification catalyst body 22 which is one of the carbon monoxide removal catalyst bodies of the present invention. A purification upstream thermocouple 23 and a purification downstream thermocouple 24 for detecting temperatures are provided on the side and the downstream side, respectively. Further, a heat exchanging portion 26 for controlling the reformed gas temperature introduced into the purifying catalyst body 22 is installed at the purifying portion inlet 21.

  In addition, the shape of the catalyst body used for each of the reforming unit 1, the transformation unit 5 and the purification unit 7 was a spherical shape of 2 to 3 mm.

These catalysts are catalysts generally used in hydrogen generators, and the effect of the present invention does not change even when other catalysts having similar functions are used. For example, a Ni catalyst is used as a reforming catalyst, a Pt catalyst or an iron-chromium catalyst is used as a shift catalyst, and a Ru catalyst or a Pt—Ru alloy catalyst is used as a purification catalyst. Further, the shape is not spherical but a columnar shape, a honeycomb shape, or the like is also used.

  Next, the operation of the hydrogen generator in this embodiment will be described.

  The raw material to be supplied to the reforming unit 1 includes organic compounds composed of at least carbon and hydrogen such as methane, propane, city gas, natural gas, hydrocarbons such as LPG, alcohols such as methanol, gasoline, kerosene, and naphtha. There are materials, and reforming methods include steam reforming in which steam is added and partial reforming in which air is added. Here, a case where a reformed gas is obtained by steam reforming natural gas will be described.

  Natural gas as a raw material is supplied from the raw material supply unit 3 to the reforming unit 1. Water is supplied from the water supply unit 4, evaporated in the reforming unit 1, mixed with the raw material, and brought into contact with the reforming catalyst body filled in the reforming unit 1.

  In the reforming unit 1, the supply amounts of the raw material and water are adjusted so that the water vapor / carbon ratio (steam carbon ratio, hereinafter referred to as S / C) is about 2.5 to 3.5. When S / C is lower than 2, carbon is deposited on the reforming catalyst, or the conversion rate from the raw material to hydrogen decreases. Conversely, when the S / C is high, it is necessary to increase the amount of heating in the heating unit 2 in order to evaporate water, and the efficiency of the hydrogen generator may be reduced. In this embodiment, S / C is set to 3.

  The reforming catalyst body is heated to 600 ° C. to 700 ° C., and the raw material and water vapor are reacted to convert to a reformed gas mainly composed of hydrogen. The composition of the generated reformed gas varies somewhat depending on the temperature of the reforming catalyst body and the ratio of steam and raw material, but as an average value excluding steam, hydrogen is about 80% by volume, carbon dioxide, carbon monoxide. About 10% by volume. This reformed gas is produced by reacting CO with water vapor by a shift reaction at a temperature of about 250 ° C. to 300 ° C. in the shift unit 5 installed downstream of the reforming unit 1, and reducing the CO concentration to 0.5 vol% Reduce to 1% by volume. Next, oxygen and CO in the air supplied from the air supply unit 6 in the purification unit 7 are selectively oxidized at a temperature of about 100 ° C. to 200 ° C. on the purification catalyst body to reduce the CO concentration to 10 ppm or less. The reformed gas from which the CO has been removed is supplied to the fuel cell power generation unit 8. The off gas after passing through the fuel cell power generation unit 8 contains hydrogen that has not been used for power generation and methane that has not been converted to hydrogen in the reforming unit, and therefore, together with the combustion gas supplied from the combustion gas supply unit 9 Combustion in the heating unit 2.

  Depending on the ambient temperature detected by the ambient temperature detector 10 outside the hydrogen generator, the catalyst temperatures of the reforming unit 1, the shift unit 5 and the purifying unit 7 are set to predetermined values set in advance with respect to the ambient temperature. The flow rate of the fuel supplied to the heating unit 2 is controlled.

  The temperature control of each catalyst is carried out by controlling the heating amount in the heating unit 2 in the reforming unit 1, controlling the cooling amount in the heat exchanging unit 16 in the transformation unit 5, and the amount of air supplied or the heat exchanging unit in the purification unit 7. This is done by controlling the cooling amount by 26. These heating unit 2, heat exchanging unit 16, and heat exchanging unit 26 correspond to the catalyst temperature control means of the present invention.

  In the present embodiment, the heat exchange unit 16 and the heat exchange unit 26 are cooled by an air fan (not shown), the temperature detected by the thermocouple 13 as the catalyst temperature of the shift unit 5, and the catalyst of the purification unit 7 The temperature detected by the thermocouple 23 was controlled as the temperature.

  Next, the principle in the present embodiment will be described.

Normally, the transformation unit 5 and the purification unit 7 perform temperature control by sensible heat of the reformed gas supplied from the reforming unit 1 at about 300 ° C. to 500 ° C. and cooling in the heat exchange unit between the reaction units. Do. At this time, if the ambient temperature is low, the air temperature sucked by the cooling air fan used in the heat exchange part is lowered and the cooling capacity in the heat exchange part is increased, or the heat radiation of the airframe of each part is increased, It may be difficult to maintain the catalyst temperature of the shift unit 5 or the purification unit 7 at a temperature necessary for the reaction. Therefore, in response to the low ambient temperature, the catalyst temperature of the reforming unit 1 is set high to increase the sensible heat of the reformed gas, or use an air fan with a large variable output range. The method of doing was taken.

  However, when the target values of the catalyst temperatures of the reforming unit 1, the shift unit 5, and the purification unit 7 are set in accordance with the low ambient temperature, the following problems occur when the ambient temperature is high.

  First, since the substantial catalyst temperature in the reforming unit 1 (temperature average value of the entire catalyst) is increased, heating the reformed catalyst more than necessary reduces the efficiency and accelerates the deterioration of the catalyst. Further, since the transformer 5 and the purifier 7 require a large cooling capacity, a large amount of electric power is required, and the efficiency of the entire system including various auxiliary devices that operate the fuel cell power generation system is reduced.

  The efficiency of the hydrogen generator is obtained by dividing the calorific value of hydrogen consumed by the fuel cell by the total calorific value of the raw material to be supplied and the heating fuel, and the heating amount for heating the reforming unit 1 is small. The higher the efficiency.

  The efficiency of the fuel cell power generation system is the efficiency of the entire system including auxiliary devices such as an inverter, a pump for driving the system, and an air fan. The smaller the power consumption of each auxiliary device, the higher the efficiency.

  On the other hand, when the temperature of the reforming catalyst body of the reforming unit 1 is changed in accordance with the ambient temperature as in the present embodiment, even when the ambient temperature is low without increasing the change range of the cooling capacity. It is possible to suppress a decrease in efficiency when the operation is stable and the ambient temperature is high. In addition, the method of changing the catalyst temperature of the reforming unit 1 according to the ambient temperature described above increases the catalyst temperature when the ambient temperature decreases, and decreases the catalyst temperature when the ambient temperature increases.

  Similarly, the catalyst temperature of the shift section 5 and the purifying section 7 is also lowered when the ambient temperature rises, and raised when the ambient temperature falls.

  The method for determining the catalyst temperature relative to the ambient temperature is not particularly limited, but the ambient temperature is changed from about 0 ° C. to about 40 ° C. using, for example, an environmental test chamber that can freely change the ambient temperature. This is done by determining the temperature condition of each catalyst part where the efficiency is highest at each temperature and creating a correspondence table.

  From these results, a relational expression between the ambient temperature and the catalyst temperature is obtained, and the catalyst temperature is changed and controlled according to the measured ambient temperature.

  In the present embodiment, cooling by an air fan is used for the heat exchanging unit 16 and the heat exchanging unit 26. However, a cooling configuration in which a heat medium such as water or a high boiling point liquid is circulated may be used. By conveying the generated water vapor or the recovered heat to the upstream side of the reforming unit 1 or the transformation unit 5, the efficiency of the apparatus can be increased. In this case as well, by changing the catalyst temperature of the reforming part etc. with respect to the ambient temperature, the difference due to the ambient temperature of the flow rate of the heat medium used for cooling can be reduced, and the control of the cooling becomes easier, When the temperature is high, the reforming section is not excessively heated.

In addition, the ambient temperature detector 10 is installed to measure the ambient temperature, but any means that can understand the ambient temperature may be used. Temperature detectors used in other parts (for example, temperature detection such as source gas temperature) The temperature detected by the device may be used. Further, the temperature detector is not limited to a thermocouple, and a thermistor generally used may be used. Furthermore, temperature data can be omitted if the data of the temperature change in the seasons and mornings and evenings of the regions and installation locations that are installed in advance are recorded in a storage device, and the control temperature of each catalyst is changed based on the data. Further, the catalyst temperature may be switched monthly, or may be simply switched in two stages of summer and winter, or four stages of spring, summer, autumn and winter. However, the effect becomes larger when the catalyst temperature is changed finely according to the ambient temperature.

  Also, a system that combines a hydrogen generator and a fuel cell is often installed with an exterior, and it is better to use a temperature that affects the characteristics of the hydrogen generator. If the heat recovery is sufficient, the temperature inside the exterior will be close to the ambient temperature, but if the heat recovery is insufficient, the temperature inside the exterior will be higher than the ambient temperature, thus affecting the hydrogen generator more than the ambient temperature. It is preferable to use the temperature inside the exterior.

  In this embodiment, the catalyst temperature is changed in accordance with the ambient temperature. However, the amount of air supplied to the purification unit 7 may be changed. In general, even if the temperature of the purification catalyst body is controlled to the same temperature, the catalyst reacts at a low temperature when the amount of air increases. For this reason, if the air amount is increased when the ambient temperature is low, the same effect as when the catalyst temperature is changed can be obtained. Conversely, when the ambient temperature is high, the amount of air is decreased.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. In the present embodiment, the method of controlling the catalyst temperature of the reforming unit 1 in conjunction with the ambient temperature 10 shown in FIG. 1 changes the S / C supplied to the reforming unit 1. This is the same as in the first embodiment. Therefore, the present embodiment will be described focusing on the different points.

  When the ambient temperature decreases, the heat radiation from the airframe in the shift unit 5 and the purification unit 7 increases, and the catalyst temperature decreases if the cooling amount is the same. In order to control to the same temperature as when the ambient temperature is high, it is possible to cope with this by reducing the cooling amount in the transformation unit 5 and the purification unit 7. However, when there is a temperature change of about 30 ° C (for example, 5 ° C to 35 ° C) in summer and winter, large power is consumed for cooling in summer, or the temperature rises too much due to insufficient cooling. Even if the cooling is out of the control range of the cooling and the cooling is stopped, the catalyst temperature falls below the reaction temperature of the catalyst. In order to avoid this, it is necessary to give a large range to the capacity of the cooling device used for the heat exchange unit 16 and the heat exchange unit 26.

  In the case of the water cooling method, the water recovered by heat usually used for cooling is supplied to the reforming unit 1 and the transformation unit 5. In this case, when the amount of cooling is changed by changing the amount of water supplied, the amount of water vapor supplied to the reforming unit 1 or the transformation unit 5 increases or decreases, resulting in a reduction in apparatus efficiency or sufficient CO. There is a possibility that it cannot be reduced. Further, when the dew point of the reformed gas is low, the fuel cell power generation unit 8 dries and the power generation efficiency decreases, and conversely, when the dew point is high, water condensation occurs and the flow path of the fuel cell power generation unit 8 is clogged. There are also challenges.

  In addition, when the transformation section 5 and the purification section 7 are cooled by an air fan, it is difficult to effectively use the heat of the reformed gas, so it is difficult to effectively use the reformed gas. When driving, the efficiency decreases.

  In the metamorphic unit 5 and the purifying unit 7, the balance between the sensible heat of the reformed gas supplied from the reforming unit 1 and the heat dissipation of the body affects the temperature. In particular, the sensible heat of water vapor in the reformed gas is large, and the temperature of the shift section 5 can be increased by increasing the S / C and increasing the amount of reformed gas supplied from the reforming section 1. By increasing / decreasing the S / C according to the ambient temperature, it is possible to operate stably even if the cooling device capacity is small.

  In addition, it is preferable to reduce the S / C when the ambient temperature is high and to increase the S / C when the ambient temperature is low as a method of changing the S / C corresponding to the ambient temperature.

  Further, since the dew point of the reformed gas increases when S / C is increased, it is preferable that the flow rate of the cooling medium is decreased by the cooling means 102 and the temperature of the fuel cell power generation unit 8 is also increased. Since water condensation in the fuel cell power generation unit 8 can be prevented, the width for changing the S / C can be increased, and when the temperature of the fuel cell power generation unit 8 is increased, the hot water supply efficiency is also increased. Moreover, since the S / C is increased in the winter when the ambient temperature is low and the demand for hot water supply is high, it is possible to avoid a shortage of hot water.

  Conversely, in summer when the ambient temperature is high, it is preferable to lower the temperature of the fuel cell power generation unit 8 by lowering the S / C and increasing the flow rate of the cooling medium by the cooling means 102. This makes it possible to suppress excess hot water.

(Example 1)
In the hydrogen generator shown in FIG. 1, the reforming unit 1 is filled with a Ru catalyst, the shift unit 5 is filled with a copper zinc catalyst, and the purification unit 7 is filled with a Pt catalyst. This hydrogen generator was installed in an environmental test room, and an experiment was conducted with the ambient temperature set to 5 ° C. From the raw material supply unit 3, 4 L of methane per minute was added in the water supply unit 4 so that the S / C was 3, and supplied to the reforming unit 1. The amount of combustion in the heating unit 2 was adjusted so that the Ru catalyst in the reforming unit 1 was 700 ° C., and reformed gas was generated. The transformation unit 5 was controlled by an air fan attached to the heat exchange unit 16 so that the detected temperature of the thermocouple 13 installed upstream of the transformation unit shown in FIG. The purification unit 7 was controlled by an air fan attached to the heat exchange unit 26 so that the detected temperature of the thermocouple 23 installed upstream of the purification unit shown in FIG. In this embodiment, the detected temperature of the shift upstream thermocouple is used as the temperature of the shift catalyst body, but the detected temperature of the shift downstream thermocouple may be used. Similarly, the detected temperature of the purified downstream thermocouple may be used as the catalyst temperature of the purified catalyst body.

  When the temperature of each part was sufficiently stabilized, the efficiency obtained by dividing the calorific value of the hydrogen consumed in the fuel cell by the total of the calorific value of the raw material for supplying the heating fuel was 80%.

  Next, the atmospheric temperature was changed to 35 ° C., the temperature of the reforming section 1 was controlled to 680 ° C., the catalyst temperature of the shift section 5 was controlled to 260 ° C., and the catalyst temperature of the purification section 7 was controlled to 130 ° C. 83%.

  Further, when the CO concentration of the reformed gas discharged from the purification unit 7 was measured, both conditions were 5 ppm.

(Example 2)
In Example 1, the S / C was 2.8, the reforming part catalyst temperature was 700 ° C., the reforming part catalyst temperature was 280 ° C., and the purifying part catalyst temperature was 150 ° C. with the ambient temperature set at 35 ° C. The efficiency was found to be 82%.

  Furthermore, at the above atmospheric temperature of 35 ° C., S / C is controlled to 2.8, the catalyst temperature of the reforming section is 680 ° C., the catalyst temperature of the shift section is 260 ° C., and the catalyst temperature of the purification section is controlled to 130 ° C. Was found to be 83.5%.

  Moreover, when the CO concentration of the reformed gas discharged from the purification unit 7 was measured, it was 6 ppm and 5 ppm, respectively.

(Comparative Example 1)
In Example 1, the atmospheric temperature was changed to 35 ° C., and the efficiency was determined without changing the catalyst temperature as it was, and it was 81%.

(Comparative Example 2)
In Example 2, the ambient temperature was 5 ° C., the S / C was 2.8, the reforming portion catalyst temperature was 680 ° C., the transformation portion catalyst temperature was 260 ° C., and the purification portion catalyst temperature was 130 ° C. However, after a while, the temperature of the metamorphic part dropped to 250 ° C., and the CO concentration of the reformed gas discharged from the purification part 7 became 500 ppm. The efficiency was 81.5%.

  The above results are summarized in Table 1.

  As is clear from Table 1, by changing the catalyst temperature and S / C of the reforming section, the shift section, and the purifying section according to the ambient temperature, the operation is performed with higher efficiency than when the temperature and S / C are not changed. can do. In Table 1, combinations that can produce the highest efficiency when the ambient temperature changes are combinations in the case of the ambient temperature of 5 ° C. in Example 1 and the efficiency of 83.5% in Example 2. .

  In the hydrogen generator of the present invention, each catalyst body is controlled to an optimum temperature according to the change in ambient ambient temperature, and can operate stably while maintaining high power generation efficiency under conditions where the temperature fluctuations due to the season are large. This is advantageous in that it is useful as a fuel cell system for home use, portable use, automobile use, etc. using this hydrogen generator.

1 is a schematic longitudinal sectional view showing a configuration of a hydrogen generator and a fuel cell power generator according to Embodiment 1 of the present invention. Schematic longitudinal cross-sectional view which shows the structure of the transformation | transformation part which concerns on Embodiment 1 of this invention Schematic longitudinal cross-sectional view which shows the structure of the purification | cleaning part which concerns on Embodiment 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reforming part 2 Heating part 3 Raw material supply part 4 Water supply part 5 Transformation part 6 Air supply part 7 Purification part 8 Fuel cell power generation part 9 Combustion gas supply part 10 Ambient temperature detector 11 Transformation part inlet 12 Transformation catalyst 13 Transformation Upstream thermocouple 14 transformation downstream thermocouple 15 transformation section outlet 16 transformation heat exchange section 21 purification section inlet 22 purification catalyst body 23 purification upstream thermocouple 24 purification downstream thermocouple 25 purification section outlet 26 heat exchange section 101 reforming section thermocouple 102 Cooling means

Claims (7)

A reforming section that reacts a raw material containing an organic compound with water to generate a reformed gas containing hydrogen;
A carbon monoxide removal unit having at least a transformation unit that reduces carbon monoxide in the reformed gas generated by the reforming unit by a shift reaction;
The temperature of the reforming catalyst body filled in the reforming section or the temperature downstream of the reforming catalyst body, the temperature of the carbon monoxide removal catalyst body filled in the carbon monoxide removal section, or the carbon monoxide removal catalyst. Catalyst temperature detection means for detecting either the upstream side or downstream side reformed gas temperature of the medium as the catalyst temperature;
Catalyst temperature control means for controlling the detected temperature to be a predetermined catalyst temperature;
An ambient temperature detecting means for detecting the outside air temperature or the ambient temperature of the hydrogen generator, or an ambient temperature predicting means for predicting the ambient temperature,
A hydrogen generating apparatus, wherein the catalyst temperature or the ratio of water to the raw material is changed based on the ambient temperature obtained from the ambient temperature detecting means or the ambient temperature predicting means. The catalyst temperature of at least one of the reforming unit and the carbon monoxide removing unit is increased when the ambient temperature is decreased, and the catalyst temperature is decreased when the ambient temperature is increased. Hydrogen generator. The hydrogen generator according to claim 1, wherein when the ambient temperature is lowered, the ratio of water to the raw material supplied to the reforming unit is increased, and when the ambient temperature is increased, the ratio is decreased. The carbon monoxide removing unit is for selectively oxidizing the oxidant gas supply unit, the oxidant gas supplied from the oxidant gas supply unit, and the carbon monoxide in the reformed gas to reduce the carbon monoxide. The hydrogen generator according to claim 1, further comprising: a purifying unit, wherein when the ambient temperature decreases, the amount of oxidant gas supplied from the oxidant gas supply unit is increased. A storage device that records the relationship between the location of the hydrogen generator or the local date and temperature and the temperature data, and the ambient temperature predicting means predicts based on the temperature data stored in the storage device. The hydrogen generator according to claim 1. A fuel cell system comprising: the hydrogen generator according to any one of claims 1 to 5; and a fuel cell that generates electric power using an oxidant gas containing oxygen and a fuel gas containing hydrogen supplied from the hydrogen generator. . The fuel cell includes a cooling unit that circulates the cooling medium and controls the temperature of the fuel cell according to the flow rate of the cooling medium. When the ratio of water to the reforming unit is increased, the fuel cell temperature is increased by the cooling unit. The fuel cell system according to claim 6, wherein when the ratio of water to the reforming unit is decreased, the fuel cell temperature is lowered by the cooling means.

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