JP2006219328A - Hydrogen generation apparatus and fuel cell system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen generation apparatus which enables quick start-up, high efficiency and stable operation, and to provide a fuel cell-power generation system using the apparatus. <P>SOLUTION: The hydrogen generation apparatus is provided with: a reforming section for generating a reformed gas containing at least hydrogen and carbon monoxide by reacting a raw material containing organic compounds with water; a conversion section having a conversion catalyst for lowering carbon monoxide content in the reformed gas by a shift reaction; a catalyst-temperature detection section comprising at least one temperature detection means arranged in the conversion section; and a control section for sequentially comparing the detected temperature from the temperature detection means with at least one target temperature increasing stepwise at start-up, and for increasing the flow of the raw material to the upper limit flow value defined in each target temperature. <P>COPYRIGHT: (C)2006,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 are expected to be applied to household cogeneration systems because the heat generated during power generation can be used effectively for hot water supply and heating. 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 as a power generation unit is underway.

  Many fuel cells generate electricity using hydrogen as fuel. At present, the hydrogen gas infrastructure that serves as the fuel is not in place. Therefore, at the place where the power generator 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. Further, the generated reformed gas contains carbon dioxide and carbon monoxide (hereinafter referred to as CO) derived from the raw materials as by-products in addition to hydrogen. Since the polymer electrolyte fuel cell currently under development operates at a low temperature of 100 ° C. or lower, CO is easily poisoned by the battery electrode catalyst, and in order to maintain the activity of the battery electrode catalyst, It is necessary to reduce as much CO as possible (generally 10 to 50 ppm or less). Therefore, in the hydrogen generator, a CO removal unit comprising a reforming unit that generates hydrogen gas, a shift unit that shifts CO and water in the reformed gas, and a CO selective oxidation unit that performs an oxidation reaction of CO. Are used together. The reforming section, the shift section, and the CO selective oxidation 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, when starting the hydrogen generator and generating the reformed gas from which CO has been removed, the reforming section is heated by a heating burner to raise the temperature, and the reforming section and the selective oxidation section are modified by the reforming section. Heated by the heat of quality gas and an external electric heater. In particular, the metamorphic part generally has a slow catalytic reaction rate, so the amount of catalyst is larger than that of other parts, and it takes time to raise the temperature. If the raw material flow rate is increased when the temperature of the catalyst is low, the treatment capacity of the catalyst exceeds the allowable amount, the CO concentration after passing through the shift section increases, and the power generation capacity of the fuel cell decreases.
Therefore, a technique has been proposed in which the temperature of the metamorphic portion is controlled by a temperature controller, and when the temperature reaches a predetermined value, the raw material flow rate starts to rise (see, for example, Patent Document 1). As a result, the time until power generation can be shortened, and the CO can be increased to the rated power generation while the CO is reduced to an optimal CO concentration without causing a sudden decrease in the power generation capacity of the fuel cell.
JP 200431280 A

  However, as described above, the metamorphic portion has a large catalyst capacity. Normally, the single-catalyst temperature detection can estimate the processing capacity of the catalyst in the vicinity where the temperature detection means is provided, but the catalyst processing over the entire catalyst is possible. It is difficult to estimate the capacity (allowable amount of raw material flow rate), and when it is heated by an electric heater, it is difficult to accurately detect the temperature distribution of the entire catalyst by heating the heater. In particular, when the hydrogen generating device is restarted after a sufficient stop period so that the temperature inside the device is reduced to the same level as the outside temperature (hereinafter referred to as a cold start), it is not so much until the device restarts from the device stop. When the start-up is started again at a temperature higher than the outside air temperature (hereinafter referred to as hot start) without passing the period, a difference occurs in the temperature distribution of the shift catalyst temperature after the start of start-up. It becomes more difficult to estimate the treatment capacity of the catalyst by temperature detection. Therefore, if the flow rate of the raw material is increased at the same temperature during the hot start at a predetermined temperature at which the raw material is allowed to rise during the cold start in the fuel cell system disclosed in Patent Document 1, the CO concentration in the reformed gas after circulation through the shift section May not be able to be suppressed to an optimum concentration, which may cause problems such as delays in starting and hindering stable operation of the fuel cell.

  Therefore, the present invention solves the above-described problems related to the conventional hydrogen generator, and when the raw material flow rate is increased to the maximum flow rate based on the temperature of the shift catalyst body, It is an object of the present invention to provide a hydrogen generator and a fuel cell power generation system that can reduce the CO concentration to an optimum concentration in the metamorphic section.

  In order to solve the above-described problem, a first hydrogen generator according to the present invention includes 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 shift section having a shift catalyst body for reducing carbon monoxide in the reformed gas by a shift reaction, and a control section, and the control section is configured so that the temperature of the shift catalyst body during the apparatus start-up operation is The upper limit flow rate defined by the target temperature when it is determined directly or indirectly that the target temperature, which is a pair of temperature values provided for each of the upstream temperature and downstream temperature of the shift catalyst body, has been reached. It is characterized by increasing the raw material flow rate to a value.

  Here, in the first hydrogen generator, when the raw material flow rate is the upper limit flow value, the target temperature is the temperature within the hydrogen generator when the hydrogen generator is stopped or started. Regardless of whether the carbon monoxide concentration in the reformed gas after passing through the shift section is equal to or lower than a predetermined allowable carbon monoxide concentration, a pair of temperature values of the upstream temperature and the downstream temperature of the shift catalyst body are used. it can.

  The control unit further includes upstream temperature detection means for detecting the temperature of the reformed gas upstream of the shift catalyst body, and downstream temperature detection means for detecting the temperature of the reformed gas on the downstream side. When both the upstream temperature detected by the temperature detecting means and the downstream temperature detected by the downstream temperature detecting means are equal to or higher than the pair of temperature values, it is directly determined that the temperature of the shift catalyst body has reached the target temperature or higher. It can also be determined.

  In addition, a downstream temperature detection means for detecting the downstream temperature of the shift catalyst body is provided, and the control unit is based on the elapsed time from the stop of the hydrogen generator to the start of the startup operation, and the startup operation measured in advance at the elapsed time With reference to the temperature profile of the upstream temperature and downstream temperature of the shift catalyst body after the start, the downstream temperature detected by the downstream temperature detecting means is estimated from the temperature profile that both the upstream temperature and the downstream temperature are equal to or higher than a pair of temperature values. When the temperature becomes equal to or higher than the downstream temperature, it can be indirectly determined that the temperature of the shift catalyst body has reached the target temperature or higher.

  In addition, a downstream temperature detection unit that detects a downstream temperature of the shift catalyst body is provided, and the control unit preliminarily determines the downstream temperature based on the downstream temperature detected by the downstream temperature detection unit at the start of the start-up operation of the hydrogen generator. Referring to the measured temperature profile of the upstream and downstream temperatures of the shift catalyst body after starting the start-up operation, the downstream temperature detected by the downstream temperature detecting means is a pair of temperature values from the temperature profile. When the temperature becomes equal to or higher than the downstream temperature estimated to be above, it can be indirectly determined that the temperature of the shift catalyst body has reached the target temperature or higher.

  A second hydrogen generator according to the present invention includes 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, and one of the reformed gases. A shift unit having a shift catalyst body for reducing carbon oxide by a shift reaction, and a control unit, the control unit, depending on the target temperature after the temperature of the shift catalyst body becomes equal to or higher than a predetermined target temperature in the apparatus start-up operation When the raw material flow rate is increased to a predetermined upper limit flow rate value, the target temperature is changed according to the apparatus stop time or the apparatus internal temperature at the start of the apparatus start.

  Here, in the second hydrogen generator, the control unit is defined according to the apparatus stop time or the apparatus internal temperature after the apparatus start-up, and when the raw material flow rate is the upper limit flow rate value, The target temperature can be changed to the temperature of the shift catalyst body in which the carbon monoxide concentration in the reformed gas is equal to or lower than a predetermined allowable carbon monoxide concentration.

In addition, it comprises a downstream temperature detection means for detecting the temperature of the reformed gas downstream of the shift catalyst body,
The control unit can also change a predetermined target temperature with respect to the downstream temperature detected by the downstream temperature detecting means according to the apparatus stop time that is an elapsed time from the stop of the operation of the hydrogen generator to the start of the operation.

  The apparatus further comprises a downstream temperature detecting means for detecting the temperature of the reformed gas downstream of the shift catalyst body, and the hydrogen generator is a downstream temperature detected by the downstream temperature detecting means at the start of the starting operation. The predetermined target temperature with respect to the downstream temperature detected by the downstream temperature detecting means can be changed according to the internal temperature.

  Further, in the first and / or second hydrogen generator according to the present invention, the target temperature is constituted by a plurality of target temperatures that increase in stages, and an upper limit flow rate value is defined by the plurality of target temperatures, respectively. The control unit can lower the temperature of the reforming unit as the upper limit flow rate value increases. Moreover, the control part can also reduce the ratio of the water with respect to a raw material with the raise of an upper limit flow value. Moreover, the control part can also reduce the increase rate of a raw material flow rate with a raise of an upper limit flow rate value.

  Moreover, in the 1st and / or 2nd hydrogen generator which concerns on this invention, a control part can also raise target temperature in conjunction with at least one of the frequency | count of starting of an apparatus, and operation time.

  A fuel cell system according to the present invention includes a hydrogen generator according to any one of claims 1 to 13, an oxidant gas containing oxygen, and a fuel gas containing hydrogen supplied from the hydrogen generator. And a fuel cell that generates electricity using the battery.

  According to the present invention, when starting the hydrogen generator, the raw material flow rate is increased stepwise in accordance with the temperature state of the shift section, so that the CO concentration in the reformed gas after the shift of the shift section is suppressed. However, the optimum raw material flow rate can be increased. Accordingly, it is possible to provide a hydrogen generator and a fuel cell power generation system that can be started up quickly and realize stable operation.

Embodiments according to the present invention will be described below with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a block diagram illustrating an example of a configuration of a fuel cell power generation system including a hydrogen generator according to the present embodiment. 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. The reforming unit 1 is provided with a raw material supply unit 3 for supplying a raw material containing an organic compound composed of at least carbon and hydrogen, and a reforming water supply unit 4 for supplying water to the reforming unit 1. A selective oxidation air supply unit 6 for supplying an oxygen-containing gas containing oxygen (air in the present embodiment) and a CO to the downstream side of the reforming unit 1 are a CO conversion unit 5 and a downstream side of the CO conversion unit 5. A fuel cell power generation unit 8 is installed on the downstream side of the selective oxidation unit 7 and further on the CO selective oxidation unit 7. The off-gas 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 when the apparatus is started up or when the heating amount for heating the reforming unit 1 is insufficient.

  In addition, a reforming unit thermocouple (not shown) for detecting the temperature of the reforming catalyst body is installed in the reforming unit 1 by filling a reforming catalyst body carrying Ru on alumina.

  Further, as shown in FIG. 2, the inside of the CO conversion unit 5 is filled with a copper zinc catalyst as the CO conversion catalyst body 22, and the conversion unit detects the temperatures on the upstream side and the downstream side of the CO conversion catalyst body 22, respectively. An upstream thermocouple 23 and a transformer downstream thermocouple 24 are installed. Further, a shift section heat exchange section 26 for controlling the temperature of the CO shift catalyst body 22 is installed at the shift section reformed gas inlet 21.

  In addition, a CO selective oxidation catalyst body in which Ru is supported on alumina is filled in the CO selective oxidation section 7 and a selective oxidation section thermocouple (not shown) for detecting the temperature of the CO selective oxidation catalyst body is installed. It is.

  The catalyst bodies used in the reforming unit 1 and the CO selective oxidation unit 7 have a spherical shape of 2 to 3 mm, and the catalyst body used in the CO conversion unit 5 has a cylindrical shape. These catalysts are catalysts generally used in hydrogen generators, and the effects in the present invention are not changed even when other catalysts having the same function are used. For example, a Ni catalyst can be used as the reforming catalyst, a Pt catalyst or an iron-chromium catalyst can be used as the CO conversion catalyst, and a Pt catalyst or a Pt—Ru alloy catalyst can be used as the CO selective oxidation catalyst. Further, in addition to a spherical shape or a cylindrical shape, a honeycomb shape or the like can also be used.

  In addition, an electrical heater for heating is installed in the CO conversion unit 5 and the CO selective oxidation unit 7 (not shown) for speeding up the temperature rise.

  In addition, the control device 10 uses the detection data of thermocouples installed in the reforming unit 1, the CO conversion unit 5, and the CO selective oxidation unit 7, and the raw materials supplied from the raw material supply unit 3 and the reforming water supply unit 4 The amount of water supplied and the amount of heating in the heating unit 2 are controlled.

  Further, the flow path switching valve 11 supplies the reformed gas to the fuel cell power generation unit 8 while the CO concentration in the reformed gas after passing through the CO selective oxidation unit 7 is not sufficiently reduced when the hydrogen generator is started. Instead, it is a switching valve for supplying the reformed gas directly to the heating unit 2 and burning it.

Next, the operation of the hydrogen generator in this embodiment will be described.
Examples of the raw material supplied to the reforming unit 1 include organic compounds containing at least carbon and hydrogen exemplified by alcohols such as methane, propane, city gas, natural gas, LPG and methanol, gasoline, kerosene, naphtha and the like. The 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 reforming 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 ratio represented by the number of moles of steam supplied to the reforming unit 1 / the number of moles of carbon atoms in the raw material supplied to the reforming unit 1 (steam carbon ratio, hereinafter referred to as S / C) It is preferable to adjust the feed amounts of the raw material and the reforming water so that (shown) is 2.5 to 3.5. When S / C is lower than 2.5, carbon is deposited on the reforming catalyst, or the conversion rate from the raw material to hydrogen decreases. Conversely, when S / C is higher than 3.5, 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 containing hydrogen as a main component. 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. As an average value excluding steam, hydrogen is about 80% by volume, carbon dioxide, carbon monoxide. About 10% by volume. This reformed gas reacts with CO and water vapor by a shift reaction at a temperature of about 250 ° C. to 300 ° C. in the CO conversion section 5 installed on the downstream side of the reforming section 1 so that the CO concentration is 0.5 vol%. Reduce to ~ 1% by volume. Next, CO in the air supplied from the selective oxidizing air supply unit 6 and CO are reacted at a temperature of 100 ° C. to 200 ° C. in the CO purification unit 7 to remove 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.

  When the hydrogen generator is started, fuel is supplied to the heating unit 2 from the combustion gas supply unit and ignited. The raw material and water are supplied from the raw material supply unit 3 and the reforming water supply unit 4. Perform the reforming reaction. At the same time, the electric heaters installed in the CO conversion unit 5 and the CO selective oxidation unit 7 are energized to start heating. When the temperature of the reforming unit 1 increases, the temperature of the reformed gas supplied to the CO conversion unit 5 increases. In the CO shift section 5, a shift section upstream thermocouple 23 and a shift section downstream thermocouple 24 are installed on the upstream and downstream sides of the shift section, respectively. The upstream thermocouple 23 is a reformed gas before passing through the shift catalyst body. The downstream thermocouple 24 detects the temperature of the reformed gas after passing through the shift catalyst body, thereby detecting the temperature state of the shift section 5.

  When the temperature of the CO conversion unit 5 rises to a predetermined temperature, the CO concentration after passing through the CO conversion unit 5 decreases to a predetermined value. When the CO concentration after passing through the CO conversion unit 5 decreases to a predetermined concentration (in this embodiment, the CO concentration is about 0.5%), the concentration at which the CO selective oxidation unit 7 can supply CO to the fuel cell power generation unit 8 Can be removed. That is, since the CO concentration after passing through the CO selective oxidation unit 7 becomes 10 ppm or less, supply of the reformed gas to the fuel cell power generation unit 8 is started by the flow path switching valve 11. At the same time, the electric heaters of the CO conversion unit 5 and the CO selective oxidation unit 7 are stopped to suppress wasteful power consumption. Note that the allowable CO concentration in the CO selective oxidation unit 7 in this embodiment is 0.5%, and if it is less than this, the CO concentration after passing through the CO selective oxidation unit 7 can be removed to 10 ppm or less. .

  In general, the power generation output of the fuel cell power generation unit 8 can be changed according to the required power at home. In this embodiment, the power can be changed from 1000 W to 300 W. For this reason, in the hydrogen generator, the amount of hydrogen (reformed gas amount) to be generated is changed by controlling the flow rate of the raw material supply unit 3 according to the output from the fuel cell power generation unit 8.

  When the hydrogen generator is started, it takes time to sufficiently warm the temperature of the CO conversion unit 5 having a large catalyst capacity. When the raw material flow rate corresponding to the maximum output of the fuel cell power generation unit 8 is suddenly supplied, the CO conversion unit 5 is turned on. The CO concentration after passing becomes high and cannot be removed even by the CO selective oxidation unit 7, and it takes a considerable time to supply the reformed gas to the fuel cell power generation unit 8 and start power generation, resulting in poor energy efficiency. . Therefore, in the present invention, a method of starting power generation from the lowest output (300 W in the present embodiment) until the CO transformer 5 is warmed to a predetermined temperature at the time of start-up can be used to start power generation earlier. At this time, the upper limit flow rate value of the raw material flow rate corresponding to the power generation amount of 300 W is 1.5 NL per minute (flow rate converted to 0 ° C.), and the CO concentration can be sufficiently reduced by the CO shift unit 5 at this flow rate (for example, CO 2 When the temperature reaches a temperature that can be reduced to a concentration of 0.5% or less, the reformed gas is supplied to the fuel cell power generation unit 8 to start power generation. Further, when the temperature of the CO conversion section 5 rises, the upper limit value of the output is increased in order of 500 W, 750 W, and 1000 W, and the upper limit value of the raw material flow rate is increased to 2 NL, 3 NL, and 4 NL per minute correspondingly. I let you. If the raw material flow rate is less than or equal to the upper limit flow rate value, the processing capacity of the CO conversion unit 5 can be accommodated, so that the CO concentration does not increase even if the raw material flow rate is freely changed.

  Here, the operation method at the time of starting the hydrogen generator will be described with reference to the flowchart of FIG. After starting, the raw material flow rate is set to a low initial flow rate value. In step S1, the control unit 10 sets the upstream temperature and the downstream temperature of the transformation unit measured at two points of the transformation unit upstream thermocouple 23 and the transformation unit downstream thermocouple 24 in advance for the upstream temperature and the downstream temperature, respectively. When it is determined that the actual upstream temperature and downstream temperature are higher than the target temperature in comparison with the target temperature that is a pair of temperature values, the process proceeds to step S2 and supply of the reformed gas to the fuel cell power generation unit 8 is started. To do. Next, the process proceeds to step S3, and the target temperature is changed to a higher new target temperature. Then, the process proceeds to step S4, and when it is determined that the actual upstream temperature and the downstream temperature are higher than the target temperature, the process proceeds to step S5, and the upper limit defined by the target temperature and larger than the initial flow rate value. Increase the raw material flow rate to the flow rate value. Next, in step S6, it is determined whether or not the upper limit flow rate value is smaller than a preset maximum flow rate value. If it is determined that the upper limit flow rate value is smaller, the process proceeds to step S3, and step S3 and subsequent steps are repeated. If it is determined in step S6 that the upper limit flow rate value is the maximum flow rate value, the maximum flow rate value is maintained, and the startup is completed. On the other hand, when it is determined in step S1 that the actual upstream temperature and downstream temperature are smaller than the target temperature, the initial flow rate value is maintained, and step S1 is repeated until the temperature of the metamorphic portion rises and reaches the target temperature. .

  FIG. 6 shows an example of the relationship between the upper limit flow rate value of the raw material that can reduce the CO concentration after passing through the transformation section to 0.5% or less, and the upstream temperature and downstream temperature of the transformation section. The upper limit flow rate value of the raw material is set in four stages of 1.5, 2, 3, 4 NL / min, and 4 NL / min is the maximum flow rate value. The upper limit of the upstream temperature of the metamorphic part is 200 ° C. As shown in the figure, when the temperatures upstream of the metamorphic part and downstream of the metamorphic part reach (130 ° C, 105 ° C), it is determined that the CO concentration can be reduced to 0.5% or less, and the fuel cell power generation When the supply of the reformed gas to the part 8 is started and further exceeds (140 ° C., 135 ° C.), (160 ° C., 150 ° C.), (190 ° C., 160 ° C.), 2 NL / min, 3 NL / min and 4 NL, respectively. It is set to increase the upper limit flow rate value of the raw material flow rate to / min. After the start-up of the device, if the upstream temperature and downstream temperature rise and reach the temperature in the region of the upper limit flow rate value 2NL / min in the figure, the CO concentration after passing through the metamorphic part can be increased even if the raw material flow rate is increased to 2NL / min. It can be suppressed to 0.5% or less of the allowable concentration. The same is true even if the transformation temperature reaches a region of 3NL / min and 4NL / min (maximum flow rate).

  Usually, since the reaction rate of the catalytic reaction increases as the temperature increases, the upper limit flow rate value of the raw material gas can be increased. On the other hand, the shift reaction proceeding in the CO shift zone has a relatively slow reaction rate in the temperature range usually used, and it is necessary to increase the capacity of the catalyst, and the catalyst tends to have a temperature distribution. In particular, since the reformed gas is circulated from the upstream side or heated by an electric heater or the like at the time of start-up, the temperature distribution of the catalyst can be considered in various states, and it is difficult to grasp the temperature distribution. The shift section uses the temperature measured at the downstream portion of the shift catalyst body as the representative temperature of the shift catalyst body.

However, if only the downstream temperature of the shift catalyst body is used as a representative temperature, the target temperature is set only for this downstream temperature, and control is performed to increase the raw material flow rate based on the shift catalyst body temperature as described above, the startup There is a possibility that the CO concentration in the reformed gas after passing through the shift section cannot be reduced to the allowable CO concentration due to the temperature in the apparatus (particularly the shift section) at the start.
Specifically, when using it for home use, various driving states are conceivable, and it may stop at night and start early in the morning. In this case, start-up (hot start) is performed while the reactor is not sufficiently cooled down. In the hot start, the time for the downstream temperature of the shift catalyst body to rise to a predetermined temperature after the start is short is short. Therefore, even if the temperature on the downstream side of the CO conversion unit 5 reaches a predetermined temperature, the temperature on the upstream side becomes lower. More specifically, although the upstream temperature and the downstream temperature differ depending on the time after the stop, the temperature state becomes (135 ° C, 135 ° C), (150 ° C, 150 ° C), (170 ° C, 160 ° C). It was. In this case, since the upstream temperature of the shift catalyst body is lower than when the hydrogen generator is restarted after a sufficient stop period that the internal temperature is reduced to the same level as the outside temperature (cold start), the upstream portion of the catalyst The reaction rate is low, the target temperature is set only at the downstream temperature, and when the control is performed to increase the raw material flow rate based on the above-described shift catalyst body temperature, the CO concentration after passing through the CO shift section 5 increases, The allowable CO concentration of the CO selective oxidation unit 7 exceeded 0.5%. On the other hand, if the target temperature that can be reduced to the allowable CO concentration is set as a combination of the upstream temperature and the downstream temperature of the CO conversion unit 5 as in this embodiment, the temperature state of the CO conversion unit is accurately set. In both the hot start and the cold start, the detected temperature of the shift catalyst and the target temperature are maintained while maintaining the CO concentration in the reformed gas after the CO shift section 5 below the allowable CO concentration. Based on the comparison, the raw material flow rate upper limit value can be increased stepwise up to the raw material flow rate corresponding to the maximum output of the fuel cell.

  In this embodiment, the shift section upstream thermocouple 23 and the shift section downstream thermocouple 24 are configured to detect the temperature of the reformed gas before and after passing through the CO shift catalyst body, respectively. Even if the thermocouple is in contact with the upstream portion and the downstream portion of the shift catalyst body, the thermocouple measures the reformed gas temperature flowing through the upstream portion and the downstream portion of the CO shift catalyst body. The temperature detected by the thermocouple may be used as the representative temperature of the upstream temperature and the downstream temperature of the transformation unit. Further, although a thermocouple is used as the temperature detection means, a thermistor or the like that measures temperature by a change in resistance may be used.

  Further, in order to quickly raise the temperature of the CO conversion unit 5 and raise the raw material to the maximum flow rate value, the CO conversion unit 5 is in the process of raising the raw material flow rate to the maximum flow rate value based on the above-described control. The supplied reformed gas temperature, that is, the temperature of the reforming section, is preferably made higher than the temperature of the reforming section during steady operation after raising the raw material flow rate to the maximum flow rate value. For this reason, while the upper limit flow rate value of a raw material is low, it is good to make the temperature of the modification part 1 high. For example, in the present embodiment, the temperature of the reforming unit 1 is controlled to 640 ° C. during steady operation, but when the upper limit flow rate value of the raw material is 1.5 NL, 2NL, 3NL per minute, When the control temperatures were 670 ° C., 660 ° C., and 650 ° C., respectively, the time required to raise the upper limit flow rate value of the raw material to the maximum of 4 NL / min could be shortened by 5 minutes.

  Further, in order to quickly raise the temperature of the CO conversion unit 5 and raise the raw material to the maximum flow rate value, the ratio of water to the raw material is increased while the raw material flow rate is raised to the maximum flow rate value based on the above control. It is preferable to increase. This is because the amount of heat of the reformed gas can be increased and the temperature rise of the CO shift section 5 can be accelerated. For example, when the upper limit flow rate value of the raw material is 1.5 NL, 2NL, and 3NL per minute and the steam carbon ratio (S / C) is 3.6, 3.4, and 3.2, respectively, The time until the upper limit flow rate value was increased to the maximum of 4 NL could be shortened by 3 minutes.

  Normally, the raw material flow rate is increased at a constant rate, and when the raw material flow rate is rapidly increased, the CO concentration after passing through the CO conversion unit 5 increases. For example, if the upper limit flow rate of the raw material is increased at a constant rate of 0.1 NL per minute at an increase rate of 1.5 NL, 2NL, 3NL, 4NL per minute, it takes 25 minutes to increase to the maximum output. It cost. At this time, the CO concentration after passing through the metamorphic part is 0.3% or less. On the other hand, when it was increased at a constant rate of 0.2 NL per minute, it could be shortened to about half an hour to increase to the maximum output, but the CO concentration increased when it was increased from 3 NL to 4 NL. The CO concentration after passing through the CO transformation section 5 exceeded 0.5%.

  However, the output of the fuel cell power generation unit 8 can be increased without increasing the CO concentration beyond the allowable CO concentration by slowing the increase rate of the raw material flow rate in the vicinity of the maximum output of the fuel cell power generation unit 8. The increase from 1.5 NL to 2 NL is 0.2 NL per minute, from 2 NL to 3 NL is 0.15 NL per minute, and the increase from 3 NL to 4 NL is 19 minutes at a rate of 0.1 NL. It was. In this way, as the upper limit flow rate value of the raw material flow rate increases, the increase time to the maximum output of the fuel cell power generation unit 8 is shortened without increasing the CO concentration by slowing the increase rate of the raw material flow rate. be able to.

  Moreover, it is preferable to raise the target temperature in conjunction with at least one of the number of start-up times, the number of stoppages, and the cumulative operation time. For example, memorize the number of activations within a predetermined time in the past, and if the number of activations is greater than the predetermined number of times, it is determined that the temperature of the device at the time of activation is equal to or higher than the predetermined temperature, and is less than the predetermined temperature It is possible to use a method of setting a target temperature lower than that in the case of. Further, the operation time immediately before the stop is stored, and when the operation time immediately before the stop is longer than the predetermined operation time, it is determined that the temperature of the apparatus at the start-up is equal to or higher than the predetermined temperature, and the predetermined temperature It is possible to use a method of setting a lower target temperature than when the temperature is less than In addition, it stores both the number of activations in the past predetermined time and the operation time immediately before the stop, and if the number of activations and the operation time is greater than the predetermined number and operation time, a lower target temperature is set than when it is low You can also

Embodiment 2. FIG.
The hydrogen generator according to the present embodiment includes a timer that measures an elapsed time from when the hydrogen generator is stopped to the start of the start-up operation in the control unit, and from the elapsed time measured by the timer, A calculation unit that calculates one or more target temperatures that increase stepwise with respect to the downstream temperature is provided, and the control unit 10 changes the target temperature calculated by the calculation unit according to the elapsed time. Regarding other points, the configuration is the same as that of the first embodiment except that the upstream temperature of the CO conversion section 5 is not detected or the upstream temperature detecting means is not provided.

  The upstream temperature and downstream temperature of the CO shift section 5 decrease as a function of time after the apparatus is stopped. The higher the temperature of the CO conversion unit 5 at the start of the hydrogen generator, the shorter the time to rise to the predetermined temperature. However, as described in the first embodiment, the downstream temperature of the CO conversion unit 5 is the same. However, when the upstream temperature is low, the CO concentration increases when the raw material flow rate is increased, which may exceed the allowable amount. In the present embodiment, the calculation unit calculates one or more target temperatures that increase stepwise with respect to the downstream temperature according to the elapsed time measured by the timer, and the control unit 10 calculates the calculated target temperature. Is changed as a new target temperature, and when it is determined that the downstream temperature has reached or exceeded each target temperature, control is performed to increase the raw material flow rate to the upper limit flow rate value defined by each target temperature. The target temperature is determined according to the elapsed time from the stop of the apparatus to the start of the apparatus by the arithmetic unit when the concentration of carbon monoxide in the reformed gas after passing through the shift section is predetermined when the raw material flow rate is the upper limit flow rate value. It is a value calculated as the temperature of the shift catalyst body that falls below the allowable carbon monoxide concentration. As a specific calculation method, for example, the temperature profile of the upstream temperature and downstream temperature of the transformer after the start of the apparatus is measured every time elapsed from the stop of the apparatus to the start of the apparatus, and this temperature profile and each of the temperature profiles shown in FIG. At the intersection with the boundary indicating the upstream temperature and downstream temperature of the metamorphic section that is below the allowable carbon monoxide concentration at the upper limit flow rate value, either the upstream temperature of the metamorphic section or the downstream temperature of the metamorphic section at a predetermined elapsed time The shift portion downstream temperature that is equal to or higher than the shift portion upstream temperature and equal to or higher than the shift portion downstream temperature that achieves the allowable carbon monoxide concentration or less shown in FIG. 6 is calculated as the target temperature. Thus, as in the first embodiment, the reforming after the CO conversion section 5 is performed regardless of the elapsed time from the stop of the apparatus to the start of the apparatus (that is, both in the case of hot start and in the case of cold start). While maintaining the CO concentration in the gas below the allowable CO concentration, the upper limit value of the raw material flow rate is gradually increased to the raw material flow rate corresponding to the maximum output of the fuel cell based on the comparison between the detected temperature of the shift catalyst and the target temperature. It can be raised.

  FIG. 3 is a block diagram showing the configuration of the control unit used in the present embodiment. The control unit 10 includes a timer 13 that measures an elapsed time from when the hydrogen generator is stopped to the start of startup, and an operation that calculates one or more target temperatures that increase stepwise from the elapsed time to the downstream temperature. Part 12 is provided.

  Next, the operation method at the time of starting the hydrogen generator will be described with reference to the flowchart of FIG. After starting, the raw material flow rate is set to a low initial flow rate value. In step S <b> 10, the calculation unit stores the elapsed time since the hydrogen generator is stopped and calculates a target temperature of the downstream temperature corresponding to the elapsed time. Next, in step S11, when the control unit 10 compares the downstream temperature detected by the transformation unit with the target temperature calculated by the calculation unit and determines that the actual downstream temperature is higher than the target temperature, the control unit 10 proceeds to step S12. Supply of the reformed gas to the fuel cell power generation unit 8 is started. Next, the process proceeds to step S13, and the target temperature is changed to a higher new target temperature. Then, the process proceeds to step S14, and when it is determined that the actual downstream temperature is higher than the target temperature, the process proceeds to step S15, and the raw material is supplied up to the upper limit flow rate value defined by the target temperature and larger than the initial flow rate value. Increase the flow rate. Next, in step S16, it is determined whether or not the upper limit flow rate value is smaller than a preset maximum flow rate value. If it is determined that the upper limit flow rate value is smaller, the process returns to step S13, and step S13 and subsequent steps are repeated. If it is determined in step S16 that the upper limit flow rate value is the maximum flow rate value, the maximum flow rate value is maintained, and the startup is completed. On the other hand, when it is determined in step S11 that the actual downstream temperature is lower than the target temperature, the initial flow rate value is maintained, and step S11 is repeated until the temperature of the shift section rises and reaches a new target temperature.

  FIG. 8 shows an example of the relationship between the upper limit flow rate value of the raw material, the time from the stop to the start of the hydrogen generator and the target temperature of the downstream temperature of the metamorphic part. If it is less than 1 hour after stopping the apparatus, the upper limit flow rate value of the raw material can be set to the maximum flow rate value. In addition, when one hour or more has passed since the stop, the calculation unit calculates a target temperature for the downstream temperature of the transformation unit according to the elapsed time, and compares the target temperature with the downstream temperature of the transformation unit step by step. The raw material flow rate is controlled by the flow of FIG. 7 in which the upper limit flow rate value is increased. The target temperature for each upper limit flow rate value when starting after the elapsed time of 1 hour or more has passed is higher than the target temperature when stopping and starting and stopping for a long time, but the time from stop to start As becomes longer, the target temperature of the downstream temperature gradually decreases. In addition, since temperature will fall to room temperature when 8 hours or more pass, when elapsed time is 8 hours or more, it will stop for a long term and will converge to the target temperature at the time of starting and stopping. Specifically, in the present embodiment, when the time from the stop to the start of the hydrogen generator is 8 hours or longer, the reforming is performed on the fuel cell power generation unit 8 when the downstream temperature of the shift unit exceeds the target temperature of 105 ° C. Gas supply is started, and when the target temperature exceeds 135 ° C, 150 ° C, and 160 ° C, the upper limit flow rate of the raw material flow rate is increased to 2NL, 3NL, and 4NL per minute, respectively. Similarly, in the case of 4 hours or more and less than 8 hours, supply of the reformed gas to the fuel cell power generation unit 8 is started when the downstream temperature of the shift unit exceeds the target temperature 110 ° C., and further, the downstream temperature of the shift unit is When the target temperature exceeds 140 ° C, 155 ° C, and 165 ° C, the upper limit value of the raw material flow rate is increased to 2NL, 3NL, and 4NL per minute, respectively. When the temperature exceeds ℃, the supply of reformed gas to the fuel cell power generation unit 8 is started. Further, when the target temperature exceeds 145 ° C, 160 ° C, 170 ° C, up to 2NL, 3NL, and 4NL per minute, respectively. The upper limit flow rate value was set to increase. If the downstream temperature of the shift section exceeds the target temperature of 115 ° C. for 1 hour or more and less than 2 hours, supply of the reformed gas to the fuel cell power generation section 8 is started, and the target temperatures of 150 ° C., 165 ° C., When the temperature exceeded 175 ° C., the upper limit flow rate value of the raw material flow rate was increased to 2 NL, 3 NL, and 4 NL per minute, respectively. Furthermore, if the time is less than 1 hour after the stop, the catalyst temperature is sufficiently high, so the target temperature is not particularly set, and the upper limit flow rate value is set as the maximum flow rate value 4 NL / min. Control is performed to start the supply of the reformed gas to the battery power generation unit 8. As a result, as described above, the raw material flow rate corresponding to the maximum output of the fuel cell is maintained while maintaining the CO concentration in the reformed gas after the CO shift section 5 at or below the allowable CO concentration as in the case of the first embodiment. It becomes possible to raise the raw material flow rate upper limit step by step.

Embodiment 3 FIG.
The hydrogen generator according to the present embodiment has a downstream temperature storage unit that stores a temporal change in downstream temperature after the hydrogen generator is stopped in the control unit, and from the downstream temperature of the transformation unit at the start of startup, The same as in the first embodiment except that a calculation unit that determines one or more target temperatures that increase stepwise with respect to the downstream temperature is provided, and the upstream temperature of the transformation unit is not detected or the upstream temperature detection means is not provided. It has the composition of.

  The upstream temperature and downstream temperature of the CO shift section 5 decrease as a function of time after the apparatus is stopped. The higher the temperature of the CO conversion unit 5 at the start of the hydrogen generator, the shorter the time to rise to the predetermined temperature. However, as described in the first embodiment, the downstream temperature of the CO conversion unit 5 is the same. However, when the upstream temperature is low, the CO concentration increases when the raw material flow rate is increased, which may exceed the allowable amount. In the present embodiment, the calculation unit calculates one or more target temperatures that increase stepwise with respect to the downstream temperature of the transformation unit according to the downstream temperature of the transformation unit at the start of device startup, and the control unit 10 When the calculated target temperature is changed as a new target temperature and it is determined that the downstream temperature has reached the target temperature or higher, control is performed to increase the raw material flow rate to the upper limit flow rate value defined by each target temperature. Do. Note that the target temperature is determined by the calculation unit according to the downstream temperature of the shift unit at the start of device startup, when the raw material flow rate is the upper limit flow rate, and the carbon monoxide concentration in the reformed gas after passing through the shift unit is a predetermined value. This is a value calculated as the temperature of the shift catalyst body that is below the allowable carbon monoxide concentration. As a specific calculation method, for example, the time change data of the downstream temperature of the shift unit is stored in the downstream temperature storage unit, the time change data is referred to from the downstream temperature of the shift unit at the start of the start of the device, and the device is started after the stop The elapsed time until the start is obtained, and based on this elapsed time, the target temperature for the downstream temperature of the metamorphic portion is calculated by the same method as in the second embodiment. Thus, as in the first embodiment, the reforming after the CO conversion section 5 is performed regardless of the elapsed time from the stop of the apparatus to the start of the apparatus (that is, both in the case of hot start and in the case of cold start). While maintaining the CO concentration in the gas below the allowable CO concentration, the upper limit value of the raw material flow rate is gradually increased to the raw material flow rate corresponding to the maximum output of the fuel cell based on the comparison between the detected temperature of the shift catalyst and the target temperature. It can be raised.

  FIG. 4 is a block diagram showing the configuration of the control unit used in the present embodiment. The control unit 10 is provided with a downstream temperature storage unit 14 that stores a temporal change in downstream temperature after the hydrogen generator is stopped, and a calculation unit 12 that determines one or more target temperatures that increase stepwise with respect to the downstream temperature. ing.

  Next, the operation method at the time of starting the hydrogen generator will be described with reference to the flowchart of FIG. After starting, the raw material flow rate is set to a low initial flow rate value. In step S <b> 20, the calculation unit calculates a target temperature for the transformation unit downstream temperature according to the transformation unit downstream temperature immediately after the start of startup. Next, in step S21, when the control unit 10 compares the detected downstream temperature of the transformation unit with the target temperature calculated by the calculation unit and determines that the actual downstream temperature is higher than the target temperature, the control unit 10 proceeds to step S22. Then, supply of the reformed gas to the fuel cell power generation unit 8 is started. Next, the process proceeds to step S23, and the target temperature is changed to a higher new target temperature. Then, the process proceeds to step S24, and when it is determined that the actual downstream temperature is higher than the target temperature, the process proceeds to step S25, and the raw material is supplied up to the upper limit flow rate value defined by the target temperature and larger than the initial flow rate value. Increase the flow rate. Next, in step S26, it is determined whether or not the upper limit flow rate value is smaller than a preset maximum flow rate value. If it is determined that the upper limit flow rate value is smaller, the process returns to step S23, and step S23 and subsequent steps are repeated. If it is determined in step S26 that the upper limit flow rate value is the maximum flow rate value, the maximum flow rate value is maintained, and the startup is completed. On the other hand, when it is determined in step S21 that the actual downstream temperature is lower than the target temperature, the initial flow rate value is maintained, and step S21 is repeated until the temperature of the shift section rises and reaches a new target temperature.

FIG. 10 shows an example of the relationship between the upper limit flow rate value of the raw material, the downstream temperature at the time of startup, and the target temperature of the downstream temperature. If the downstream temperature of the transformation section at the start of startup is less than 80 ° C., the supply of the reformed gas to the fuel cell power generation section 8 is started when the downstream temperature of the transformation section exceeds the target temperature of 105 ° C., and further, the downstream temperature of the transformation section Is set to increase the upper flow rate of the raw material to 2 NL, 3 NL, and 4 NL per minute when the target temperature exceeds the target temperatures of 135 ° C., 150 ° C., and 160 ° C., respectively. Similarly, when the downstream temperature of the transformation unit at the start of startup is 80 ° C. or higher and lower than 120 ° C., supply of the reformed gas to the fuel cell power generation unit 8 is started when the target temperature exceeds 110 ° C., and further, the target temperature 140 ° C. When the temperature exceeds 155 ° C and 165 ° C, the upper limit flow rate of the raw material is set to 2 NL, 3 NL, and 4 NL per minute, respectively. The supply of reformed gas to the fuel cell power generation unit 8 is started when the downstream temperature exceeds the target temperature 115 ° C., and when the target temperature exceeds 145 ° C., 160 ° C., and 170 ° C., 2 NL per minute. The upper limit flow rate of the raw material was set to be increased to 3NL and 4NL. Furthermore, when the downstream temperature of the transformation section at the start of startup is 140 ° C. or more and less than 150 ° C., supply of the reformed gas to the fuel cell power generation section 8 is started when the target temperature exceeds 120 ° C., and further, the transformation section downstream temperature When the target temperature exceeded 150 ° C., 165 ° C., and 175 ° C., the upper limit flow rate of the raw material was increased to 2 NL, 3 NL, and 4 NL per minute, respectively. When the downstream temperature at the start of the transformation is 150 ° C. or higher, the catalyst temperature is sufficiently high. Therefore, the target temperature is not set as the downstream temperature of the transformation, and the upper limit flow rate value is 4NL. When reaching, the fuel cell power generation unit 8 is controlled to start supplying the reformed gas. As a result, the raw material flow rate upper limit is gradually increased to the raw material flow rate corresponding to the maximum output of the fuel cell while maintaining the CO concentration in the reformed gas after the CO conversion unit 5 below the allowable CO concentration as in the first embodiment. The value can be increased.
When the downstream temperature of the transformation section at the start of startup is 150 ° C or higher, the upper limit flow rate value is maximized even though the target temperature 175 ° C for the maximum flow rate value 4NL at 140 ° C or higher and lower than 150 ° C is not reached. The flow rate value can be set because the downstream temperature of the transformation unit reaches 175 ° C. or more while the raw material flow rate is gradually increased (for example, 0.2 NL / min) to the maximum flow rate value. The CO concentration in the gas can reach the maximum flow rate value without exceeding the CO allowable concentration.

  As described above, according to the present invention, when the hydrogen generator is started up, the control unit is not limited to the temperature detected from the temperature detection means of the shift unit and the elapsed time since the stop of the device, and the shift unit is at a predetermined raw material flow rate. It is ensured that the CO concentration in the reformed gas after that is equal to or less than the allowable CO concentration, and one or more target temperatures that increase stepwise are sequentially compared, and the raw material flow rate reaches the upper limit flow rate value defined by each target temperature. Therefore, the optimum raw material flow rate can be increased while suppressing the CO concentration in the reformed gas after flowing through the shift section. Accordingly, it is possible to provide a hydrogen generator and a fuel cell power generation system that can be started up quickly and realize stable operation.

It is a block diagram which shows an example of a structure of the hydrogen generator which concerns on Embodiment 1 of this invention, and a fuel cell power generation system. It is a model longitudinal cross-sectional view which shows an example of a structure of the CO transformation part of FIG. It is a block diagram which shows an example of a structure of the control part used for the hydrogen generator based on Embodiment 2 of this invention. It is a block diagram which shows an example of a structure of the control part used for the hydrogen generator which concerns on Embodiment 3 of this invention. It is a control flowchart of the control part in Embodiment 1 of this invention. It is a graph which shows the relationship between the upstream temperature and downstream temperature in Embodiment 1 of this invention, and the upper limit of a raw material flow volume. It is a control flowchart of the control part in Embodiment 2 of this invention. It is a graph which shows the relationship between the upstream temperature and downstream temperature in Embodiment 2 of this invention, and the upper limit of raw material flow volume. It is a control flowchart of the control part in Embodiment 3 of this invention. It is a graph which shows the relationship between upstream temperature and downstream temperature in Embodiment 3 of this invention, and the upper limit of raw material flow volume.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reforming part 2 Heating part 3 Raw material supply part 4 Reformed water supply part 5 CO conversion part 6 Selective oxidation air supply part 7 CO selective oxidation part 8 Fuel cell power generation part 9 Combustion gas supply part 10 Control apparatus 11 Flow path switching valve DESCRIPTION OF SYMBOLS 12 Computation part 13 Timer 14 Downstream temperature memory | storage part 21 Transformation part reformed gas inlet 22 CO transformation catalyst body 23 Transformation part upstream thermocouple 24 Transformation part downstream thermocouple 25 Transformation part reformed gas outlet 26 Transformation part heat exchange part

Claims (14)

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 shift section having a shift catalyst body for reducing carbon monoxide in the reformed gas by a shift reaction;
A control unit,
The control unit directly determines that the temperature of the shift catalyst body has reached a target temperature that is a pair of temperature values provided for each of the upstream temperature and the downstream temperature of the shift catalyst body during the apparatus start-up operation. A hydrogen generator that increases the raw material flow rate to an upper limit flow rate value defined by the target temperature when determined manually or indirectly.   When the raw material flow rate is the upper limit flow value, the target temperature is the reformed gas after passing through the shift section regardless of the operation time of the hydrogen generator or the temperature in the hydrogen generator at the start of startup. 2. The hydrogen generator according to claim 1, wherein the hydrogen generator is a pair of temperature values of an upstream temperature and a downstream temperature of the shift catalyst body so that a concentration of carbon monoxide therein becomes equal to or less than a predetermined allowable carbon monoxide concentration.   The control unit further comprises upstream temperature detection means for detecting the temperature of the reformed gas upstream of the shift catalyst body, and downstream temperature detection means for detecting the temperature of the reformed gas downstream. When both the upstream temperature detected by the detecting means and the downstream temperature detected by the downstream temperature detecting means are equal to or higher than the pair of temperature values, it is directly determined that the temperature of the shift catalyst body has reached the target temperature or higher. The hydrogen generator according to claim 1 or 2, wherein the hydrogen generator is automatically determined. A downstream temperature detecting means for detecting a downstream temperature of the shift catalyst body;
The controller, based on the elapsed time from the stop of the hydrogen generator to the start of the start-up operation, the temperature profile of the upstream temperature and the downstream temperature of the shift catalyst body after the start of the start-up operation measured in the elapsed time The transformation is performed when the downstream temperature detected by the downstream temperature detecting means is equal to or higher than the downstream temperature estimated from the temperature profile that both the upstream temperature and the downstream temperature are equal to or higher than the pair of temperature values. The hydrogen generator according to claim 1 or 2, wherein the temperature of the catalyst body is indirectly determined as having reached the target temperature or higher. A downstream temperature detecting means for detecting a downstream temperature of the shift catalyst body;
The control unit, based on the downstream temperature detected by the downstream temperature detection means at the start of the startup operation of the hydrogen generator, the upstream temperature of the shift catalyst body after the start of the startup operation measured in advance at the downstream temperature and With reference to the temperature profile of the downstream temperature, the downstream temperature detected by the downstream temperature detection means is equal to or higher than the downstream temperature estimated from the temperature profile that both the upstream temperature and the downstream temperature are equal to or higher than the pair of temperature values. 3. The hydrogen generator according to claim 1, wherein the temperature of the shift catalyst body is indirectly determined as having reached the target temperature or higher. 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 shift section having a shift catalyst body for reducing carbon monoxide in the reformed gas by a shift reaction;
A control unit,
When the raw material flow rate is increased by the control unit from the time when the temperature of the shift catalyst body becomes equal to or higher than a predetermined target temperature to the upper limit flow rate value defined by the target temperature in the device startup operation, A hydrogen generator that changes the target temperature in accordance with the temperature inside the apparatus at the start of startup.   The control unit is defined according to the apparatus stop time or the apparatus internal temperature after the apparatus start-up, and when the raw material flow rate is the upper limit flow value, monoxide in the reformed gas after passing through the shift unit The hydrogen generation apparatus according to claim 6, wherein the target temperature is changed to a temperature of the shift catalyst body that has a carbon concentration equal to or lower than a predetermined allowable carbon monoxide concentration. A downstream temperature detecting means for detecting the temperature of the reformed gas downstream of the shift catalyst body;
The control unit changes the predetermined target temperature with respect to the downstream temperature detected by the downstream temperature detecting means according to the apparatus stop time which is an elapsed time from the stop of operation of the hydrogen generator to the start of operation. The hydrogen generator according to claim 7. Comprising downstream temperature detecting means for detecting the temperature of the reformed gas downstream of the shift catalyst body,
Further, the hydrogen generating device has a predetermined target temperature with respect to the downstream temperature detected by the downstream temperature detecting means according to the internal temperature which is the downstream temperature detected by the downstream temperature detecting means at the start of the starting operation. The hydrogen generator according to claim 8, wherein The target temperature consists of a plurality of target temperatures that increase stepwise, and the upper limit flow rate value consists of a plurality of upper limit flow rate values respectively defined by the plurality of target temperatures,
The hydrogen generation apparatus according to claim 1, wherein the control unit decreases the temperature of the reforming unit as the upper limit flow rate value increases. The target temperature consists of a plurality of target temperatures that increase stepwise, and the upper limit flow rate value consists of a plurality of upper limit flow rate values respectively defined by the plurality of target temperatures,
The said control part is a hydrogen generator of Claim 1 or 6 which reduces the ratio of the water with respect to a raw material with the raise of the said upper limit flow value. The target temperature consists of a plurality of target temperatures that increase stepwise, and the upper limit flow rate value consists of a plurality of upper limit flow rate values respectively defined by the plurality of target temperatures,
The hydrogen generation apparatus according to claim 1, wherein the control unit decreases the increase rate of the raw material flow rate as the upper limit flow rate value increases.   The hydrogen generation apparatus according to claim 1, wherein the control unit raises the target temperature in conjunction with at least one of the number of activations of the apparatus and the operation time. A hydrogen generator according to any one of claims 1 to 13, 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. A fuel cell system provided.

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