JP5235368B2 - Fuel reformer - Google Patents

Description

  The present invention relates to a fuel reformer for a fuel cell that reforms raw fuel into reformed gas used in the fuel cell.

  A polymer electrolyte fuel cell generates electric power by converting chemical energy of hydrogen into electric energy. Practically, hydrogen used as a fuel for a polymer electrolyte fuel cell is obtained by using natural gas, a hydrocarbon gas such as naphtha, or a raw fuel gas such as alcohol such as methanol and water vapor, which are relatively easy and inexpensive to obtain. It is obtained by mixing and reforming with a fuel reformer. Hydrogen gas obtained by reforming is supplied to the fuel electrode of the fuel cell and used for power generation.

In the reforming process, first, after the temperature of the reforming catalyst reaches 400 to 600 ° C. due to heating of the burner, reforming water that is steam necessary for reforming is supplied. After the reforming catalyst temperature reaches 600 to 700 ° C. by further heating, the raw fuel is supplied and reforming is started.
JP 2005-158428 A

  When reforming is once stopped and then reforming is started again, it is necessary that the fuel reformer is sufficiently cooled. When the cooling water is not sufficiently cooled, the supplied reforming water causes bumping due to the residual heat in the fuel reformer, and the amount of the supplied steam becomes unstable. When reforming is performed in such a state, the S / C (steam / carbon) ratio representing the ratio of reformed water and raw fuel is lowered, and the concentration of carbon monoxide contained in the reformed gas is significantly increased. When the reformed gas having a high carbon monoxide concentration is supplied to the fuel electrode of the fuel cell, the carbon monoxide adheres to the catalyst particles of the fuel electrode, thereby reducing the function of the catalyst.

  The present invention has been made in view of such problems, and its purpose is to provide a technique capable of reducing the carbon monoxide concentration in the reformed gas by suppressing the bumping of the reformed water after the start of reforming. is there.

One embodiment of the present invention is a fuel reformer. The fuel reformer includes a reformer that generates reformed gas from raw fuel and steam, a fuel supply unit that supplies raw fuel to the reformer, and a steam supply unit that supplies steam to the reformer And a control unit for controlling the supply of raw fuel by the fuel supply unit, wherein the steam supply unit generates a steam to be supplied to the reformer, First temperature detection means for detecting the temperature of water in the water vapor supply section, and the control section controls the supply of raw fuel according to the temperature detected by the first temperature detection means, and the water vapor A supply part produces | generates superheated steam from the 1st heating part which produces | generates non-superheated steam, and the non-superheated steam produced | generated by the said 1st heating part, and supplies the produced | generated superheated steam to the said reformer. A second heating unit, and the first heating unit The first temperature detecting means is provided on a path through which the non-superheated steam supplied from the section to the second heating section flows, and the reformer includes a catalyst and causes the raw fuel and steam to react with each other. A reaction part, a combustion part for heating the reaction part, and a second temperature detection means for detecting the temperature of the reaction part, the temperature detected by the second temperature detection means being at the time of the catalyst reaction The temperature exceeding the temperature necessary for suppressing the generation of unreacted substances and by-products, and the temperature detected by the first temperature detection means continues to rise above the boiling point of water, and the first temperature detection After the amount of change per unit time of the temperature detected by the means changes from positive to negative or from positive to zero, when the temperature falls within a temperature range where no reforming water bumps occur, the control unit Starting supply of raw fuel by fuel supply means And characterized in that.

  According to the present invention, the carbon monoxide concentration in the reformed gas can be reduced by suppressing the bumping of the reformed water after the start of reforming.

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

  FIG. 1 is a block diagram schematically showing the fuel reformer 100. The fuel reformer 100 includes a reformer 200 that generates reformed gas from raw fuel and steam, fuel supply means that supplies raw fuel to the reformer 200, and steam that supplies steam to the reformer 200. Supply means and a control unit 900 are provided. The control unit 900 mainly controls the supply of raw fuel by the fuel supply means, but can also control other members in the fuel reformer 100.

  The reformer 200 includes a reaction unit 220 that reacts the supplied raw fuel with water vapor, a burner 230 for heating the reaction unit 220, and a thermometer 210 for measuring the temperature of the reaction unit 220. The reaction unit 220 includes a catalyst for reacting raw fuel and water vapor. In the burner 230, the reformed gas that has not been consumed by a fuel cell (not shown) may be burned.

  The fuel supply means includes a raw fuel source 300 and a desulfurizer 310. The raw fuel source 300 supplies raw fuel, which is fuel before being reformed, to the reformer 200. The raw fuel source 300 may be in the form of a gas cylinder containing a hydrocarbon-based gas or the like that is a raw fuel, or supply raw fuel by being connected to a gas pipe with city gas as a supply source. May be. The desulfurizer 310 is used to remove sulfur compounds contained in the raw fuel. After passing through the desulfurizer 310, the raw fuel is mixed with the steam that has passed through the throttle 420 and supplied to the reformer 200. Between the raw fuel source 300 and the desulfurizer 310, control members such as a pump, a flow meter, and a valve (not shown) are provided. In FIG. 1, the movement of fuel is indicated by a double line.

  The steam supply means measures the flow rate of water supplied from the water supply unit that generates steam supplied to the reformer 200, a thermometer 430 that detects the temperature of water in the steam supply unit, and the water tank 800. A flow meter 820. The steam supply unit includes a water tank 800, a pump 810, an evaporator 700, an evaporator 610, an evaporator 510, a superheated steam generator 400, a filter 410 and a throttle 420.

  The water tank 800 stores water collected from a fuel cell (not shown). The recovered water is filtered by an ion exchange resin and then stored in the water tank 800. When the water in the water tank 800 is insufficient, it is supplied from the outside. The pump 810 supplies the water in the water tank 800 to the evaporator 700. The flow meter 820 is used to adjust the flow rate supplied from the water tank 800. The control unit 900 refers to the value measured by the flow meter 820 and adjusts the amount of water required for reforming by controlling the pump 810. In FIG. 1, the movement of water and water vapor is indicated by broken lines.

  The water that has passed through the flow meter 820 is heated to about 100 ° C. by the evaporator 700 and becomes a boiling state in which gas and liquid coexist. The evaporator 700 includes a heat exchanger, and the heat of the gas heated by the burner 230 and discharged from the reformer 200 is supplied to water by the heat exchanger. The gas that has passed through the evaporator 700 is discharged to the outside of the fuel reformer 100. In FIG. 1, the movement of the gas discharged from the reformer 200 is indicated by a triple line.

  The boiling water that has passed through the evaporator 700 is further heated by the evaporator 610. The evaporator 610 also includes a heat exchanger, and the heat generated in the CO remover 600 is supplied to the boiling water by the heat exchanger. The boiling water that has passed through the evaporator 610 is further heated by the evaporator 510. The evaporator 510 also includes a heat exchanger, and heat generated in the CO converter 500 is supplied to boiling water by the heat exchanger. The water that has passed through the evaporator 610 and the evaporator 510 is still in a boiling state, and the heat supplied by the two evaporators is absorbed by the boiling water as latent heat.

  The boiling water that has passed through the evaporator 510 is further heated by the superheated steam generator 400. Boiling water in which gas and liquid coexist due to overheating by the superheated steam generator 400 becomes superheated steam in which only gas exists. That is, superheated steam refers to steam that has reached a temperature exceeding the boiling point of water. The superheated steam generator 400 also includes a heat exchanger, and the heat of the reformed gas reformed by the reformer 200 is supplied to the boiling water by the heat exchanger, and superheated steam is generated. The superheated steam sent out from the superheated steam generator 400 is 150 ° C. or higher.

A thermometer 430 is provided between the evaporator 510 and the superheated steam generator 400. The thermometer 430 measures the temperature of boiling water supplied from the evaporator 510 to the superheated steam generator 400. In order for the steam supply means to stably supply steam to the reformer 200, it is preferable to heat the water stepwise by a plurality of evaporators and the superheated steam generator 400 as shown in FIG. This is because when heating steam is rapidly generated from water by extremely high temperature heating, the water suddenly boils suddenly and the amount of steam supplied to the reformer 200 becomes unstable. In the evaporator 700, the evaporator 610 and the evaporator 510 (first heating portion), a non-overheating steam not superheated steam is generated by heating, superheated steam generation unit 400 (second heating unit), these evaporators produced by heating the superheated steam from a non-overheating steam produced by.

  The thermometer 430 measures the temperature of water to confirm that the water supplied from the evaporator 510 does not exceed the boiling point. The position of the thermometer 430 is preferably provided on a pipe connecting the evaporator 510 and the superheated steam generator 400. This is to reduce the influence of the heat exchanger included in the evaporator 510 and the superheated steam generator 400.

  The superheated steam generated by the superheated steam generator 400 passes through the filter 410. Inside the filter 410, mesh-like SUS is three-dimensionally arranged. If there is water vapor that is not completely vaporized, it is captured by the filter 410. The superheated steam that has passed through the filter 410 passes through the throttle 420 and is supplied to the reformer 200 together with the raw fuel that has passed through the desulfurizer 310. The throttle 420 functions as a resistance of the superheated steam that passes therethrough. The supply amount of superheated steam supplied to the reformer 200 can be stabilized by the throttle 420.

  The reformed gas reformed by the reaction unit 220 travels from the reformer 200 to the superheated steam generation unit 400. In FIG. 1, the movement of the reformed gas is indicated by a solid line. The temperature of the reformed gas reaching the superheated steam generator 400 is 400 to 500 ° C., and heat is supplied through the heat exchanger in the superheated steam generator 400. Further, the gas heated by the burner 230 is discharged from the reformer 200. The discharged gas goes to the evaporator 700 and supplies heat through a heat exchanger in the evaporator 700. In FIG. 1, the gas discharged from the reformer 200 goes directly to the evaporator 700, but it may be supplied to the evaporator 700 after supplying heat via the superheated steam generator 400.

  The reformed gas that has passed through the superheated steam generator 400 goes to the CO converter 500. The CO converter 500 reduces carbon monoxide, which is an unnecessary product contained in the reformed gas generated by the reformer 200. In the CO converter 500, in order to reduce the carbon monoxide concentration in the reformed gas, carbon monoxide and water are reacted to generate carbon dioxide and hydrogen. The reaction performed in the CO converter 500 is an exothermic reaction, but heat is required to start the reaction. Heat necessary for this is supplied by a heater 520 (third heating unit), and the heater 520 heats the catalyst in the CO converter 500. The reaction heat in the CO converter 500 and the heat from the heater 520 are supplied to boiling water through a heat exchanger in the evaporator 510.

  The reformed gas that has passed through the CO converter 500 is directed to the CO remover 600. Similarly, the CO remover 600 reduces carbon monoxide which is an unnecessary product contained in the reformed gas generated by the reformer 200. That is, the CO converter 500 and the CO remover 600 are in charge of unnecessary product processing in the fuel reformer 100. The carbon monoxide concentration in the reformed gas is reduced by the CO converter 500, but it is necessary to further reduce the concentration of carbon monoxide in order to use it as fuel in the fuel cell. The CO remover 600 reacts carbon monoxide with oxygen to produce carbon dioxide, thereby reducing the carbon monoxide concentration to a usable level. The reaction performed in the CO remover 600 is an exothermic reaction, but heat is required to start the reaction. Heat necessary for this is supplied by a heater 620, and the heater 620 heats the catalyst in the CO remover 600. The reaction heat in the CO remover 600 and the heat from the heater 620 are supplied to boiling water through a heat exchanger in the evaporator 610.

  The reformed gas that has passed through the CO remover 600 is supplied to the fuel electrode of the fuel cell outside the fuel reformer 100.

  FIG. 2 is a flowchart showing a normal startup sequence of the fuel reformer 100. When the fuel reformer 100 is activated, the burner 230 in the reformer 200 starts heating the reaction unit 220. Furthermore, the heater 520 in the CO transformer 500 and the heater 620 in the CO remover 600 also start heating. The controller 900 monitors the measured value of the thermometer 210 that measures the temperature of the reaction unit 220. When the measured value is less than 500 ° C. (N in S10), the control unit 900 continues to monitor the measured value. When the measured value of the thermometer 210 reaches 500 ° C. or higher (Y in S10), the control unit 900 starts the pump 810 and starts the supply of reforming water from the water tank 800 (S12).

  The control unit 900 monitors the measurement value of the thermometer 210 even after the supply of the reforming water is started. When the measured value is less than 600 ° C. (N in S14), the control unit 900 continues to monitor the measured value. When the measured value of the thermometer 210 reaches 600 ° C. or more (Y in S14), the control unit 900 starts supply of raw fuel from the raw fuel source 300 (S16). Thereby, in the reformer 200, reforming with raw fuel and steam is performed.

  FIG. 3 is a graph schematically showing temperature changes of the thermometer 210 and the thermometer 430 in the startup sequence. The activation sequence in FIG. 2 will be described with reference to FIG. The normal startup sequence described in FIG. 2 is indicated by a broken line in FIG.

When the fuel reforming apparatus 100 is started, the heating of the reaction unit 220 is started by the burner 230, so that the measured value of the thermometer 210 starts to rise. The measured value of the thermometer 210 reaches 500 ° C. when the time t ₃ has elapsed from the start of the start of the fuel reformer 100. As shown in S12 of FIG. 2, the supply of reforming water from the water tank 800 is started.

With the start of the supply of the reforming water, the measured value of the thermometer 430 rapidly rises to about 100 ° C. after time t ₃ . The reason why the measured value of the thermometer 430 before the time t ₃ has changed at a low value is that the reforming water has not been supplied yet, so the thermometer 430 is connected to the pipe connecting the superheated steam generator 400 and the evaporator 510. This is because the temperature is only measured.

Measurement of the thermometer 210 will continue to rise time _{t 3} thereafter reaches the time _{t 4} to 600 degrees. As shown in S <b> 16 of FIG. 2, raw fuel is supplied from the raw fuel source 300, and reforming is started in the reformer 200. The reason why the measured value of the thermometer 210 is stable in the state of exceeding 600 ° C. after the time t _{4 is} that the heating of the burner 230 is adjusted by the control unit 900 so as not to fall below 600 ° C. This is because if the reforming is performed at a temperature lower than 600 ° C., unreacted substances and by-products are generated during the catalytic reaction in the reaction unit 220. The unreacted material here is raw fuel, and by-products include carbon dioxide, hydrocarbons having a smaller number of carbon than raw fuel, carbon (carbon), and the like.

The measured value of the thermometer 430 is stable at around 100 ° C. after the time t ₃ . The reformed water supplied from time t ₃ to t ₄ is heated by the evaporator 700, heated by the evaporator 610 due to the heat of the heater 620, and heated by the evaporator 510 due to the heat of the heater 520. In the position, it becomes boiling water. Therefore, the measured value of the thermometer 430 changes at a value around 100 ° C. from time t ₃ to t ₄ .

On the other hand, since the reforming is started after time t ₄ , the reformed water is heated by the evaporator 700, heated by the evaporator 610 due to the reaction heat in the CO remover 600, and reacted by the reaction heat in the CO converter 500. After heating in the evaporator 510, the water becomes boiling water at the position of the thermometer 430. As a result, the measured value of the thermometer 430 changes around 100 ° C. as in the time t ₃ to t ₄ .

  Next, activation of the fuel reformer 100 at the time of hot start will be described. Hot start means that after the fuel reforming apparatus 100 is stopped, the fuel reforming apparatus 100 is restarted in a state where residual heat exists in the evaporator 700, the evaporator 610, and the evaporator 510. On the other hand, in the normal startup described with reference to FIG. 2, after the fuel reformer 100 is stopped, the evaporator 700, the evaporator 610, and the evaporator 510 are sufficiently cooled, and there is no residual heat in these evaporators. It means starting the fuel reformer 100 in a state.

The activation at the hot start is indicated by a solid line in FIG. In the case of a hot start, since residual heat remains in the reaction unit 220, the measured value of the thermometer 210 at the time of startup is higher than that at normal times. Thereafter, the measured value of the thermometer 210 reaches 500 ° C. at a time t ₁ earlier than the normal time t ₃ . The controller 900 starts supplying reformed water. Thereby, the measured value of the thermometer 430 also starts to rise.

In the case of hot start, the time until the measured value of the thermometer 210 exceeds 500 ° C. and reaches 600 ° C. is short, and reaches 600 ° C. at time t ₂ . At this time, the measured value of the thermometer 430 continues to rise, and does not change at a value around 100 ° C. as in normal times. This is because the reformed water is rapidly heated by the residual heat existing in the evaporator 700, the evaporator 610, and the evaporator 510. Therefore, the measured value of the time t ₂ after the thermometer 430 will continue to rise for some time.

  Unlike the normal time, the measured value of the thermometer 430 continues to rise above 100 ° C. before transitioning to around 100 ° C. Because it is. Under normal conditions, the reforming water is heated in stages by a plurality of evaporators, and superheated steam is generated in the superheated steam generator 400, but at the start of hot start, any of the plurality of evaporators is caused by residual heat. Superheated steam is generated. Therefore, the thermometer 430 continues to rise above the boiling point of water.

  When the reforming water is gradually heated and raised in temperature as usual, the reforming water is stably supplied to the reformer 200. However, when the reforming water is rapidly heated as in a hot start, the reforming water undergoes bumping, and the amount of superheated steam supplied to the reformer 200 becomes unstable. As a result, the carbon monoxide concentration in the reformed gas is significantly increased. Therefore, it is necessary to stably supply superheated steam to the reformer 200 even during startup at the time of hot start.

  FIG. 4 is a flowchart showing a startup sequence of the fuel reformer 100 in consideration of a problem at the time of hot start. When the fuel reformer 100 is activated, the control unit 900 monitors the measurement value of the thermometer 210. When the measured value is less than 500 ° C. (N in S18), the control unit 900 continues to monitor the measured value. When the measured value of the thermometer 210 reaches 500 ° C. or more (Y in S18), the control unit 900 starts the pump 810 and starts the supply of reforming water (S20). Up to this point, it is the same as the normal startup sequence.

  In order to prevent bumping of the reformed water, the measured value of the thermometer 430 may correspond to 90 ° C. or higher and 120 ° C. or lower. If the measured value of the thermometer 430 changes around 100 ° C., the reformed water passing through the thermometer 430 is in a boiling state, and the reformed water becomes superheated steam in any of the plurality of evaporators. This is because rapid heating is not performed. Although the boiling point of water is 100 ° C. at 1 atm, the temperature range is set to 90 ° C. or more and 120 ° C. or less in order to give a wide range of setting values in consideration of changes in the environment in which the fuel reformer 100 is used. doing.

However, in the start-up at the time of hot start, after the measured value of the thermometer 210 exceeds 500 ° C., the measured value of the thermometer 430 may fall within the range of 90 ° C. or more and 120 ° C. or less before changing around 100 ° C. is there. For example, in FIG. 3, after the measured value of the thermometer 210 reaches 500 ° C. at time t ₁ , the measured value of the thermometer 430 continues to rise, and falls within the range of 90 ° C. or more and 120 ° C. or less before time t _2. To do. This is not because the measured value of the thermometer 430 is changing around 100 ° C., but because the measured value continues to increase due to residual heat in the evaporator.

  In order to cope with such a case, after the change amount per unit time of the measured value of the thermometer 430 (that is, the slope in the graph of FIG. 3) changes from positive to negative or from positive to zero (Y in S21), the control is performed. The unit 900 determines whether or not the measurement value of the thermometer 430 falls within the range of 90 ° C. or more and 120 ° C. or less (S22). If the change amount has not changed from positive to negative or positive to zero (N in S21), the control unit 900 continues to monitor the change amount.

  When the measured value of the thermometer 430 does not fall within the range (N in S22), the control unit 900 continues to monitor the measured value of the thermometer 430. When the measured value of the thermometer 430 falls within the range (Y of S22), the control unit 900 confirms that the measured value of the thermometer 210 is 600 ° C. or more (Y of S24), and supplies the raw fuel. Start (S26). By such a procedure, if the measured value of the thermometer 430 has not yet changed around 100 ° C. and falls within the range of 90 ° C. or higher and 120 ° C. or lower, while suppressing bumping of the reforming water, Modification can be performed.

[Example 1]
In order to verify the startup sequence according to FIG. 4, experiments were performed in the case where the normal startup sequence is performed for the hot start and the case where the startup sequence is performed according to FIG. 4 for the hot start. FIG. 5 is a graph showing the measured value of the thermometer 210, the measured value of the thermometer 430, and the concentration of carbon monoxide contained in the reformed gas when the normal startup sequence is performed.

In the normal startup sequence, the control unit 900 does not refer to the measurement value of the thermometer 430 as shown in FIG. In other words, the measured value of the thermometer 210 starts the supply of the reforming water at the time t ₅ to reach 500 ° C., the supply of the raw fuel at the time t ₆ the measured value of the thermometer 210 reaches 600 ° C. is started. The measured value of the thermometer 430 has risen to a level exceeding 120 ° C. after t ₆ , and it can be seen that the reformed water becomes superheated steam before reaching the superheated steam generation unit 400.

  The carbon monoxide concentration rises rapidly after the measured value of the thermometer 430 exceeds 120 ° C., and exceeds 800 ppm around 30 minutes. In order to protect the function of the catalyst in the fuel cell, the carbon monoxide concentration in the reformed gas must be suppressed to 10 ppm or less. In FIG. 5, since the carbon monoxide concentration exceeds 800 ppm, the reformed gas generated is not suitable for use in a fuel cell when the normal startup sequence is performed for hot start.

FIG. 6 is a graph showing the measured value of the thermometer 210, the measured value of the thermometer 430, and the concentration of carbon monoxide contained in the reformed gas when the startup sequence of FIG. 4 is performed. The measured value of the thermometer 210 reaches 500 ° C. at time t ₇ . Thereafter, the measured value of the thermometer 210 reaches 600 ° C. before 15 minutes, but the amount of change per unit time of the measured value of the thermometer 430 is positive. The amount of change changes from positive to negative after 15 minutes, and the measured value of the thermometer 430 becomes 120 ° C. or less before 20 minutes. However, since the measured value of the thermometer 210 is lower than 600 ° C. at that time, the supply of raw fuel is not started. The measured value of the thermometer 210 reaches 600 ° C. again at time t ₈ , and the control unit 900 starts supplying raw fuel.

When performing the activation sequence of FIG. 4, the carbon monoxide concentration in the reformed gas, there is little change time t ₈ subsequent reforming is started. The carbon monoxide concentration time _{t 8} after According to the experimental data is stable at 2～3Ppm. According to the startup sequence of FIG. 4, reforming can be started after the sudden boiling of reforming water has settled, and reformed gas suitable for use in a fuel cell can be generated.

[Example 2]
FIG. 7 is a flowchart showing an activation sequence corresponding to hot start and focusing on time. When the measured value of the thermometer 210 reaches 500 ° C. (Y in S28), the control unit 900 starts supplying reformed water (S30). Residual heat existing in the plurality of evaporators is gradually taken away by the supplied reforming water. After a certain amount of time has passed after the supply of the reforming water, the remaining heat is sufficiently removed and the reforming water does not bump into the evaporator.

  After supplying the reforming water, the controller 900 waits for a predetermined time until the remaining heat is sufficiently removed (S32). Thereafter, similarly, the control unit 900 confirms whether the measured value of the thermometer 430 falls within the range of 90 ° C. or higher and 120 ° C. or lower (S34), and the measurement of the thermometer 210 reaches 600 ° C. (S36). Y) The supply of raw fuel is started (S38).

  When a predetermined time for waiting for the start-up sequence was confirmed by experiments, the carbon monoxide concentration in the reformed gas could be suppressed to less than 10 ppm by waiting for 5 minutes or longer after the reforming water was supplied.

[Example 3]
FIG. 8 is a flowchart showing an activation sequence corresponding to the hot start and for starting the reforming reaction earlier. When the measured value of the thermometer 210 reaches 500 ° C. (Y in S40), the control unit 900 starts supplying reformed water (S42). Residual heat existing in the plurality of evaporators is gradually taken away by the supplied reforming water.

  The controller 900 monitors the measurement value of the thermometer 430. If the measured value of the thermometer 430 does not exceed 120 ° C. until it changes around 100 ° C. (N in S44), the reforming water has not bumped into any of the plurality of evaporators, so the control unit 900 Starts the supply of raw fuel (S52) after the measured value of the thermometer 210 reaches 600 ° C. (Y in S50).

  If the measured value of the thermometer 430 exceeds 120 ° C. before transitioning around 100 ° C. (Y in S44), bumping of reforming water has occurred in any of the plurality of evaporators. Since the remaining heat still exists in these evaporators, the controller 900 can take away the remaining heat in the evaporator more quickly by increasing the flow rate of the reforming water (S46). After the flow rate is increased, if the amount of change in the measured value of the thermometer 430 per unit time changes from positive to negative and the measured value of the thermometer 430 becomes 120 ° C. or less (Y in S48), the control unit 900 is revised. The flow rate of the quality water is restored (S49). The controller 900 starts the supply of raw fuel after the measurement of the thermometer 210 reaches 600 ° C. (Y in S50) (S52).

  When the startup sequence in FIG. 8 was actually performed, the measured value of the thermometer 430 became 120 ° C. or less in a shorter time than when the flow rate was not changed, and the reforming reaction could be started earlier. Moreover, the carbon monoxide concentration in the reformed gas could be suppressed to less than 10 ppm.

[Example 4]
FIG. 9 is a flowchart showing an activation sequence corresponding to the hot start and for starting the reforming reaction earlier. When the measured value of the thermometer 210 reaches 500 ° C. (Y in S54), the control unit 900 starts supply of reforming water (S56). Residual heat existing in the plurality of evaporators is gradually taken away by the supplied reforming water.

  The control unit 900 monitors the measurement value of the thermometer 430. When the measured value of the thermometer 430 does not exceed 120 ° C. until it changes around 100 ° C. (N in S58), no reforming water bumps occur in any of the plurality of evaporators. Starts supplying raw fuel after the measured value of the thermometer 210 reaches 600 ° C. (Y in S66) (S68).

  When the measured value of the thermometer 430 exceeds 120 ° C. before transitioning around 100 ° C. (Y in S58), bumping of the reforming water has occurred in any of the plurality of evaporators. Thus, there is still sufficient residual heat in these evaporators.

  When the start-up sequence is started in the fuel reformer 100, heating by the burner 230 of the reformer 200 is started. The gas heated by the burner 230 is sent to the evaporator 700, and further heat is supplied to the reforming water that takes away residual heat. Therefore, the control part 900 can take away the residual heat in several evaporators earlier by stopping the heating by the burner 230 (S60).

  If the amount of change per unit time of the thermometer 430 measured value changes from positive to negative after the burner 230 is stopped, and the measured value of the thermometer 430 becomes 120 ° C. or less (Y in S62), the control unit 900 Heating by the burner 230 is resumed (S64). The controller 900 starts the supply of raw fuel after the measured value of the thermometer 210 reaches 600 ° C. (Y in S66) (S68).

  When the starting sequence of FIG. 9 was actually performed, the measured value of the thermometer 430 became 120 ° C. or less in a shorter time than when the burner 230 was not stopped, and the reforming reaction could be started earlier. Moreover, the carbon monoxide concentration in the reformed gas could be suppressed to less than 10 ppm.

[Example 5]
FIG. 10 is a flowchart showing an activation sequence corresponding to the hot start and for starting the reforming reaction earlier. When the measured value of the thermometer 210 reaches 500 ° C. (Y in S70), the control unit 900 starts supply of reforming water (S72). Residual heat existing in the plurality of evaporators is gradually taken away by the supplied reforming water.

  The control unit 900 monitors the measurement value of the thermometer 430. If the measured value of the thermometer 430 does not exceed 120 ° C. until it changes around 100 ° C. (N in S74), no reforming water bumps occur in any of the plurality of evaporators. Starts the supply of raw fuel (S84) after the measurement of the thermometer 210 reaches 600 ° C. (Y in S82).

  If the measured value of the thermometer 430 exceeds 120 ° C. before transitioning around 100 ° C. (Y in S74), bumping of reforming water has occurred in any of the plurality of evaporators. Thus, there is still sufficient residual heat in these evaporators.

  When the start-up sequence is started in the fuel reformer 100, the heater 520 and the heater 620 start heating to heat the catalyst in the CO converter 500 and the CO remover 600, respectively. Part of the heat from these heaters is further supplied to the reformed water that takes away the residual heat by the heat exchanger in the evaporator 510 and the evaporator 610. Therefore, the control part 900 can take away the residual heat in an evaporator earlier by stopping the heating by these heaters (S76).

  After the heater 520 and the heater 620 are stopped, the amount of change per unit time of the thermometer 430 measured value changes from positive to negative, and the measured value of the thermometer 430 becomes 120 ° C. or less (Y in S78). The unit 900 resumes heating by the burner 230 (S80). The controller 900 starts the supply of raw fuel after the measured value of the thermometer 210 reaches 600 ° C. (Y in S82) (S84).

  When the startup sequence of FIG. 10 was actually performed, the measured value of the thermometer 430 became 120 ° C. or less in a shorter time than when the heater was not stopped, and the reforming reaction could be started earlier. Moreover, the carbon monoxide concentration in the reformed gas could be suppressed to less than 10 ppm.

[Example 6]
FIG. 11 is a flowchart showing an activation sequence corresponding to hot start. When the measured value of the thermometer 210 reaches 500 ° C. (Y in S86), the control unit 900 starts supply of reforming water (S88).

  The control unit 900 monitors the measurement value of the thermometer 210. When the measured value of the thermometer 210 is less than 600 ° C. (N in S90), the control unit 900 continues to monitor. When the measured value of the thermometer 210 is 600 ° C. or higher (Y in S90), the control unit 900 monitors the measured value of the thermometer 430. When the measured value of the thermometer 430 does not correspond to 90 ° C. or more and 120 ° C. or less (N in S92), the control unit 900 continues monitoring. When the measured value of the thermometer 430 corresponds to 90 ° C. or more and 120 ° C. or less (Y in S92), the control unit 900 starts supply of raw fuel (S94).

  The startup sequence up to FIG. 10 confirms that the measured value of the thermometer 210 is 600 ° C. or higher after the measured value of the thermometer 430 corresponds to 90 ° C. or higher and 120 ° C. or lower. However, the activation sequence in FIG. 11 changes the order of the determination. When the startup sequence of FIG. 11 was actually performed, the carbon monoxide concentration in the reformed gas could be suppressed to less than 10 ppm.

  The present invention is not limited to the above-described embodiments, and various modifications such as design changes and combinations of the embodiments can be made based on the knowledge of those skilled in the art. Embodiments to which various modifications are added can also be included in the scope of the present invention.

It is a block diagram showing a fuel reformer typically. It is a flowchart which shows the starting sequence at the normal time of a fuel reformer. It is a graph which shows typically the temperature change of two thermometers in a starting sequence. It is a flowchart which shows the starting sequence of the fuel reformer which considered the problem at the time of a hot start. It is a graph which shows the measured value of the two thermometers at the time of performing the starting sequence at the normal time, and the carbon monoxide concentration contained in the reformed gas. It is a graph which shows the measured value of two thermometers at the time of performing the starting sequence of FIG. 4, and the concentration of carbon monoxide contained in the reformed gas. It is a flowchart which shows the starting sequence corresponding to the hot start, and paying attention to time. It is a flowchart which shows the starting sequence corresponding to a hot start, and is for starting a reforming reaction earlier. It is a flowchart which shows the starting sequence corresponding to a hot start, and is for starting a reforming reaction earlier. It is a flowchart which shows the starting sequence corresponding to a hot start, and is for starting a reforming reaction earlier. It is a flowchart which shows the starting sequence corresponding to a hot start.

Explanation of symbols

  100 fuel reformer, 200 reformer, 210 thermometer, 220 reactor, 230 burner, 300 raw fuel source, 310 desulfurizer, 400 superheated steam generator, 410 filter, 420 throttle, 430 thermometer, 500 CO conversion , 510 evaporator, 520 heater, 600 CO remover, 610 evaporator, 620 heater, 700 evaporator, 800 water tank, 810 pump, 820

Claims (5)

A reformer that generates reformed gas from raw fuel and steam;
Fuel supply means for supplying raw fuel to the reformer;
Steam supply means for supplying steam to the reformer;
A control unit for controlling supply of raw fuel by the fuel supply means;
A fuel reformer comprising:
The water vapor supply means
A steam supply section for generating steam to be supplied to the reformer;
First temperature detection means for detecting the temperature of water in the water vapor supply unit;
With
The control unit controls the supply of raw fuel according to the temperature detected by the first temperature detection means,
The water vapor supply unit
A first heating unit that generates non-superheated steam;
A second heating unit that generates superheated steam from the non-superheated steam generated by the first heating unit and supplies the generated superheated steam to the reformer;
With
The first temperature detection means is provided on a path through which the non-superheated steam supplied from the first heating unit to the second heating unit flows;
The reformer is
A reaction section containing a catalyst and reacting raw fuel with water vapor;
A combustion section for heating the reaction section;
Second temperature detection means for detecting the temperature of the reaction section;
With
The temperature detected by the second temperature detecting means exceeds the temperature necessary for suppressing the generation of unreacted substances and by-products during the catalytic reaction, and the temperature detected by the first temperature detecting means is After the boiling point of water continues to rise and the amount of change per unit time of the temperature detected by the first temperature detecting means changes from positive to negative or from positive to zero, If it falls within the temperature range where no
The said control part starts supply of the raw fuel by the said fuel supply means, The fuel reformer characterized by the above-mentioned. When the temperature detected by the first temperature detecting means exceeds the temperature range where no reforming water bumps occur on the high temperature side,
2. The fuel reformer according to claim 1, wherein the control unit decreases the temperature by increasing a flow rate of reforming water supplied by the steam supply unit. When the temperature detected by the first temperature detection means exceeds the temperature range where no bumping of the reformed water heated by the exhaust heat of the combustion section occurs on the high temperature side,
The fuel reformer according to claim 1, wherein the control unit reduces the temperature by suppressing heating by the combustion unit. An unnecessary product processing unit for reducing unnecessary products contained in the reformed gas generated by the reformer;
A third heating unit for heating the catalyst in the unnecessary product processing unit;
Further comprising
When the temperature detected by the first temperature detecting means exceeds the temperature range where no bumping of the reformed water heated by the heat of the third heating unit occurs on the high temperature side,
2. The fuel reformer according to claim 1, wherein the control unit reduces the temperature by suppressing heating by the third heating unit.   5. The fuel reforming apparatus according to claim 1, wherein a temperature range in which the reforming water does not cause a sudden boiling is 90 ° C. or more and 120 ° C. or less.

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