JP5162989B2 - Reformer - Google Patents

Description

  The present invention relates to a reforming apparatus for reforming hydrocarbons such as natural gas to produce hydrogen.

  Hydrogen is expected as clean energy, and its use is being studied in various industrial fields. For example, in a fuel cell, a pair of electrodes are arranged with an electrolyte layer in between, a fuel gas containing hydrogen is supplied to one electrode (anode side), and an oxidizing gas containing oxygen is supplied to the other electrode (cathode side) Is a power generation system that obtains an electromotive force by utilizing an electrochemical reaction that occurs between the two electrodes, and can achieve high energy efficiency, and can also be used for nitrogen oxide (NOx), sulfur oxide (SOx), etc. As the amount of air pollutants emitted is small, it is expected to be used as a clean energy supply method.

  Usually, in these fuel cells, air is used as an oxidizing gas, and a gas containing hydrogen obtained by steam reforming a raw material fuel of a hydrocarbon such as natural gas is used as a fuel gas. For this reason, the fuel cell power generation apparatus equipped with such a fuel cell is provided with a hydrogen generator such as a reformer, etc., and hydrocarbons such as natural gas are connected with a continuous desulfurizer and reformer. Then, desulfurization and steam reforming are performed to obtain a reformed gas mainly composed of hydrogen.

The following equation (1) is a reforming reaction when the raw fuel is methane.
CH ₄ + H ₂ O → CO + 3H ₂ ΔH = + 206.14 KJ / mol (1)

As shown in Formula (1), the reforming reaction is an endothermic reaction. For this reason, a heat source such as a burner for heating the reformer is installed in the reformer.
Further, the reformed gas obtained by the reforming reaction contains carbon monoxide (CO), carbon dioxide (CO ₂ ) and the like in addition to hydrogen.

  Here, the fuel cell is classified into a polymer electrolyte fuel cell, a phosphoric acid fuel cell, a molten carbonate fuel cell, and the like depending on the type of electrolyte used. Among them, the molten carbonate fuel cell can use a reformed gas containing CO due to its electrolyte properties. However, in a phosphoric acid fuel cell or a solid polymer fuel cell having a relatively low operating temperature, the electrode catalyst is poisoned by CO, performance is degraded, and power generation efficiency is reduced. Therefore, in the case of a phosphoric acid fuel cell, the reformed gas generated by the reformer is supplied to the fuel cell after the CO concentration is reduced to 1% or less by the CO converter. In the polymer electrolyte fuel cell having a lower operating temperature of 60 to 80 ° C., the CO concentration was reduced to 1% or less by the CO converter, and then the CO concentration was further reduced to 10 ppm or less by the CO remover. After that, the fuel cell is supplied.

  On the other hand, in recent years, fuel cell power generation devices are often developed as a power generation capacity of about 1 kW for home use, and miniaturization is required. Therefore, in a reformer that requires a plurality of reactors as described above, the reaction steps (reforming reaction, CO shift reaction, CO selective oxidation reaction, etc.) are performed in separate reactors. Since the entire reformer becomes large, attempts have been made to downsize the reformer by integrating the reactors.

  The following Patent Document 1 includes a heat source that generates heat by combustion of fuel gas. The reaction heat is directly obtained from the heat source, and hydrocarbons such as natural gas, which is a raw fuel, are steam reformed to mainly contain hydrogen. A reformer for generating a reformed gas, a CO converter for reducing CO contained in the reformed gas generated by the reformer by a water gas shift reaction, and a reforming after the treatment by the CO converter The CO remover that selectively oxidizes and further reduces CO contained in the gas is divided into independent sections and is configured integrally, at least different from the reformer and the CO converter. The CO converter and the CO remover are arranged to be indirectly heated by heat transfer from the heat source of the raw material reforming section, and the CO remover is located on the outer peripheral side from the reformer position. Located in Reforming apparatus is disclosed that.

However, such an integrated reformer in which each reactor is integrated has a plurality of reactors (temperature ranges of each reactor; reformers: 600 to 800 ° C., CO converter: 200 -350 ° C, CO remover: 100-180 ° C) are integrally configured, and it is difficult to keep the temperature of each reactor at an appropriate reaction temperature.
In other words, the CO converter and the CO remover may be heated above their optimum temperatures due to heat transfer from the heat source of the reformer. In addition, since the chemical reaction in the CO converter and the CO remover is an exothermic reaction, these reactors are also heated by the reaction heat radiated from them, so that they are maintained at an appropriate reaction temperature. Needed cooling.
Therefore, in Patent Document 1, a cooling means such as a fan is disposed on the outer periphery of the CO converter or CO remover, and the reaction heat in the CO converter or CO remover is cooled by the cooling means, so that an optimum reaction temperature is obtained. The temperature is adjusted so that

In Patent Document 2, the reforming water supplied to the reformer is heat-exchanged with the CO converter and the CO remover, and the CO converter and the CO remover are cooled by the latent heat of vaporization of the reformed water. It is disclosed that the flow rate of reforming water supplied to the reformer is increased or decreased within a preset S / C range in accordance with the temperature of the catalyst layer of the CO converter or CO remover.
Japanese Patent No. 3403416 JP 2004-6093 A

  However, in the aspect of Patent Document 1, external cooling means or the like must be newly installed, and there is a problem that the cost of the apparatus and the operating cost required for cooling increase, and the cost of the entire system increases. In addition, with the new installation of the cooling means, there has been a problem that the reformer becomes larger.

  In Patent Document 2, the temperature of the catalyst layer of the CO converter or the CO remover is measured, and the supply amount of the reforming water is controlled based on the temperature, so that the catalyst of the CO converter or the CO remover is controlled by so-called feedback control. Since the temperature of the layer is controlled, it takes time to bring the catalyst layer of each reactor to a predetermined temperature, and overshoot and undershoot are repeated, and the temperature balance of each reactor cannot be maintained. In some cases, stable operation may be difficult.

  Accordingly, an object of the present invention is to provide a reformer that can appropriately maintain the reaction temperature of each reactor without increasing the operating cost and enlarging the apparatus.

In order to achieve the above object, a reformer of the present invention includes a first reactor that generates a reformed gas by performing a steam reforming reaction on a raw material obtained by mixing hydrocarbons that are raw fuel and reformed water. A second reactor connected to the first reactor and reducing the concentration of impurities contained in the reformed gas to produce a refined reformed gas; and reformed water for supplying the raw material to the first reactor And a raw material supply control means for controlling a supply amount of raw fuel and reformed water supplied to the reformed water- containing raw material supply path in accordance with a required amount of the refined reformed gas. The raw water-containing raw material supply path is connected to the first reactor through at least a heat exchange section with the second reactor, and the raw material supply control means supplies the reformed water-containing raw material supply path. An S / C value representing the supply amount of the reforming water per supply amount of the raw fuel as a molar ratio, Serial in conjunction with the reduction in the required amount of purified reformed gas, characterized in that it is configured to increase continuously or stepwise.

According to the reforming apparatus of the present invention, the reforming water supplied from the reforming water-containing raw material supply path to the first reactor is heated by heat exchange with the second reactor in the heat exchange section, and finally Becomes steam and is used for the reforming reaction in the first reactor. On the other hand, the second reactor is cooled because the reaction heat is taken away by heat exchange with the reforming water.
In this case, the required amount of refined reformed gas is reduced when the molar ratio of the supply amount of reforming water to the supply amount of raw fuel (hereinafter referred to as “S / C”) is maintained at a constant value. Since the supply amount of raw fuel to the first reactor needs to be reduced, the supply amount of reforming water is also reduced proportionally. As a result, the reformed water becomes steam at an early stage due to heat exchange with the second reactor, and the second reactor may not be sufficiently cooled. As a result, the temperature of the second reactor gradually increases, and the catalyst layer filled in the reactor may not be able to maintain an appropriate reaction temperature, and the impurity concentration in the reformed gas may not be sufficiently reduced.

  Therefore, in the present invention, when the required amount of refined reformed gas is reduced by the raw material supply control means, for example, as the operating load of the fuel cell power generator is reduced, the molar ratio of the supply amount of reforming water to the supply amount of raw fuel The S / C value is increased continuously or stepwise in conjunction with a decrease in the required amount of refined reformed gas. As a result, even if the required amount of the refined reformed gas decreases and the supply amount of the raw fuel decreases, it is possible to secure a sufficient amount of reforming water as a cooling medium for the second reactor. As a result, overheating of the second reactor can be suppressed and the second reactor can be maintained at an optimum reaction temperature, so that a purified reformed gas having a very low impurity concentration such as CO can be obtained.

  The raw material supply control means of the reformer of the present invention is configured so that the S / C value is set in advance for a predetermined time from when the required amount of the refined reformed gas falls below a preset lower limit value than during rated operation. It is preferable that the temperature is lowered within a set range, and then is increased continuously or stepwise in conjunction with a reduction in the required amount of the refined reformed gas.

In the operation of reducing the reformer's operating load to reduce the amount of reformed gas produced (hereinafter referred to as “partial load operation”), the S / C value is increased, thereby overheating the second reactor. However, if the refined reformed gas contains excessive water vapor, for example, when used as a fuel gas to be supplied to the fuel cell, the water vapor condenses in the gas flow path and closes the flow path. There is a risk of impairing power generation efficiency. For this reason, depending on the usage mode of the refined reformed gas, it may not be preferable to increase the S / C value indefinitely. Therefore, during this partial load operation, it is preferable to operate by shifting the temperature at which the second reactor should be maintained within a range that does not impair the CO removal efficiency to a higher temperature range than during rated operation.
According to this aspect, the operation is performed with the S / C value lowered for a predetermined time from when the required amount of the refined reformed gas falls below the preset lower limit value within a preset range from the rated operation. In other words, since the operation is performed with the supply amount of reforming water reduced, the rate of temperature increase is increased and the temperature of the second reactor can be increased quickly. Then, after raising the temperature of the second reactor in this way, the S / C value is increased continuously or stepwise in conjunction with a decrease in the required amount of purified reformed gas. The temperature rising rate of the reactor becomes slow, approaching the stabilized state, and the temperature of the second reactor can be quickly shifted to the optimum temperature for operation.

The raw material supply control means of the reformer of the present invention is preferably configured to lower the S / C value within a preset range from the rated operation for a predetermined time from the startup.
When the reformer starts up, the temperature of the second reactor may remain below the temperature range that is believed to stabilize during normal operation, and the temperature may not be stable. is there. According to this aspect, the S / C value is reduced within a preset range from the rated operation for a predetermined time from the start, that is, the supply amount of reforming water is reduced for a predetermined time from the start. Therefore, since the temperature of the second reactor can be raised to a stable temperature state quickly, the operation after startup can be performed quickly.

  In the present invention, the second reactor is preferably a CO converter and / or a CO remover.

  According to the present invention, the reforming water-containing raw material supply path is connected to the first reactor via the heat exchange section with the second reactor, and the supply amount of the reforming water per raw fuel supply amount is in a molar ratio. In order to suppress overheating of the second reactor, a raw material supply control means for continuously or stepwise increasing the S / C value expressed by Thus, the second reactor can be maintained at an optimum reaction temperature, and a purified reformed gas having a very low impurity concentration such as CO can be obtained. Moreover, since the reforming water-containing raw material is cooled by exchanging heat with the second reactor, the reaction temperature of each reactor can be appropriately maintained without causing an increase in operating cost or an increase in the size of the apparatus. A reformer can be provided.

  Hereinafter, embodiments of the reforming apparatus of the present invention will be described with reference to the drawings. FIG. 1 shows a front sectional view of an embodiment of the reforming apparatus of the present invention.

  This reformer has a combustion chamber 10 serving as a heat source for supplying a part of the raw fuel for combustion and supplying heat necessary for the reaction of each reactor. On the outer periphery of the combustion chamber 10, the first reactor 20 is arranged in a cylindrical shape. On the further outer periphery of the first reactor 20, a second reactor 30 having a cylindrical shape is disposed via a cylindrical partition wall 25.

  The first reactor 20 is a reactor that generates a reformed gas mainly composed of hydrogen from a raw fuel of hydrocarbons such as naphtha, natural gas, coal gas, and alcohols by a steam reforming reaction. What is called a reformer is preferably employed. The first reactor 20 has a cylindrical reaction chamber 20a surrounding the outer periphery of the combustion chamber 10, and the reaction chamber 20a is filled with a reforming catalyst 20b. The lower end of the first reactor 20 forms a flange-like space, and a raw material supply port 20c made of raw fuel and reforming water is formed at one place on the outer periphery thereof. A second temperature sensor 52 is disposed at the raw material supply port 20c.

  A reformed gas outlet 21 a is formed at the upper end of the first reactor 20, and this reformed gas outlet 21 a communicates with the reformed gas flow passage 21 disposed on the outer periphery of the first reactor 20. ing. A second reactor 30 is disposed on the outer periphery of the reformed gas flow passage 21 via the partition wall 25, and the reformed gas flow passage 21 is connected via a communication passage 21b disposed at the lower end portion thereof. The second reactor 30 communicates with the second reactor 30.

  The partition wall 25 is not particularly limited as long as it has a heat transfer control function. For example, a known heat insulating material or a hollow layer is preferably employed.

The second reactor 30 is a reactor for purifying by reducing the impurity concentration in the reformed gas. For example, the second reactor 30 reacts with CO in the reformed gas with water vapor to form hydrogen and CO ₂ . A CO converter that performs modification (water gas shift reaction; exothermic reaction), a CO remover that selectively oxidizes CO contained in the reformed gas (selective oxidation reaction; exothermic reaction) to produce CO _2, and the like are preferably employed. .

  In this embodiment, the second reactor 30 has a cylindrical reaction chamber, the reaction chamber is divided into a lower reaction chamber 30a and an upper reaction chamber 30b, and the lower reaction chamber 30a is shifted. The catalyst 31a is charged to form a CO converter 31, and the upper reaction chamber 30b is charged with a CO selective oxidation catalyst 32a to form a CO remover 32.

  In addition, an air supply pipe 33 for taking in air necessary for the oxidation reaction in the CO remover 32 is connected to a connection portion between the CO transformer 31 and the CO remover 32. At the upper end of the CO remover 32, a purified reformed gas delivery path 34 for delivering purified reformed gas with reduced impurities such as CO is provided.

  As the second reactor 30, the type of fuel cell to be applied, the type of raw fuel supplied to the first reactor 20, the type of catalyst charged in the first reactor 20, and the like are required. The reactor to be used can be appropriately selected depending on the purity of the purified reformed gas, and the CO converter 31 alone may be sufficient. Further, a reactor other than the CO converter 31 and the CO remover 32 may be used, or the CO converter 31 and / or the CO remover 32 and another reactor may be used in combination. In addition to the reactor using the selective oxidation reaction that selectively reacts CO with oxygen in the air to reduce the CO concentration, the CO remover can react with CO and hydrogen to cause methanation to reduce the CO concentration. It may be a reactor using a methanation reaction to be reduced.

  A raw material supply path 40 for supplying raw fuel and reforming water to the first reactor 20 is spirally wound around the outer periphery of the second reactor 30. The portion where the raw material supply path 40 is spirally wound constitutes a heat exchanging portion in the present invention. In addition, the form of the heat exchange part may be such that the space to which the reforming water is supplied is in direct contact with the second reactor via the wall surface, or a porous or the like having the property of absorbing water in the space. It may be configured to be arranged, and is not limited to a spiral tube.

  In this embodiment, the raw material supply path 40 includes a piping part 40 a that surrounds the outer periphery of the CO remover 32 and a piping part 40 b that surrounds the outer periphery of the CO transformer 31. A first temperature sensor 51 is disposed at a portion connecting the pipe part 40a and the pipe part 40b. The base end of the raw material supply path 40 forms a raw material supply port 41, and the leading end of the raw material supply path 40 is connected to the raw material supply port 20 c of the first reactor 20.

  On the other hand, the raw fuel is supplied through the raw fuel supply path L1 through the flow rate adjusting valve 45, and the reformed water is supplied through the reformed water supply path L2 through the flow rate adjusting valve 46. The raw fuel supply path L <b> 1 and the reforming water supply path L <b> 2 join in the middle and are connected to the raw material supply port 41 of the raw material supply path 40. The flow rate adjusting valves 45, 46 are electrically connected to the raw material supply control means 50, and the degree of opening and closing of the flow rate adjusting valves 45, 46 is changed by an output signal from the raw material supply control means 50, so that the raw material supply port 41. The S / C value, which is the molar ratio of the supply amount of the reforming water to the supply amount of the raw fuel to be introduced, can be changed. In this embodiment, the supply amounts of the raw fuel and the reforming water are adjusted using the flow rate adjusting valves 45 and 46. However, the flow rate adjusting valves 45 and 46 are replaced by devices such as a pump, a blower, and a compressor. Thus, the supply amounts of raw fuel and reforming water may be adjusted.

  Next, the operation method of the reformer of the present invention will be described.

  First, the flow rates of the raw fuel and reformed water are adjusted by the flow rate adjusting valves 45 and 46, and the S / C value, which is the molar ratio of the reformed water supply amount to the raw fuel supply amount, is set to a predetermined value. In this state, raw fuel and reforming water are introduced into the raw material supply port 41.

  The raw material containing raw fuel and reforming water is supplied from the raw material supply port 20 c to the first reactor 20 through the raw material supply path 40 screwed on the outer periphery of the second reactor 30. At this time, the reformed water in the raw material supply path 40 is first subjected to heat exchange in the piping section 40a surrounding the outer periphery of the CO remover 32 while passing through the raw material supply path 40, and then the outer periphery of the CO converter 31 is passed through. Heat is exchanged in the surrounding piping part 40b. In this way, it is heated by heat exchange with the second reactor 30, and finally becomes steam. At the same time, the raw fuel in the raw material supply path 40 is also heated by heat exchange with the second reactor 30 to become a raw material gas. On the other hand, in the CO remover 32 and the CO converter 31 constituting the second reactor 30, the reformed water acts as a cooling medium, and heat is taken away by heat exchange with the reformed water. The reaction temperature is maintained.

The raw fuel and reformed water gasified by heat exchange with the second reactor 30 are introduced into the first reactor 20 and undergo a reforming reaction to generate a reformed gas. The reformed gas generated in the first reactor 20 is supplied to the second reactor 30. First, in the CO converter 31 in the previous stage, CO contained in the reformed gas reacts with water vapor to generate hydrogen and CO. _{To 2} (water gas shift reaction). Thereafter, the remaining CO is selectively oxidized (selective oxidation reaction) by the oxygen in the air supplied from the air supply pipe 33 in the subsequent stage CO remover 32 to become CO ₂ , and the CO concentration in the reformed gas Is further reduced and sent as purified reformed gas from the purified reformed gas delivery path 34.

  Here, when the operation is performed by adjusting the supply amounts of the raw fuel and the reforming water so that the S / C value is always constant, for example, the operation load of the fuel cell power generation device is reduced and the refinement modification is performed. When the required amount of quality gas decreases, the supply amount of raw fuel is reduced, and the supply amount of reforming water is reduced in proportion thereto. Therefore, when the operation is performed by adjusting the supply amounts of the raw fuel and the reforming water so that the S / C value is always constant regardless of the required amount of the refined reformed gas, the reforming water as the cooling medium is used. The second reactor 30 cannot be sufficiently cooled due to a shortage of the amount of catalyst, and the second reactor 30 is overheated and the catalyst layer filled in the reactor cannot maintain an appropriate reaction temperature, and impurities in the reformed gas The concentration may not be sufficiently reduced.

  Therefore, in the present invention, based on the required amount of refined reformed gas, the raw material supply control means 50 adjusts the degree of opening and closing of the flow rate adjusting valves 45 and 46, and the raw fuel flow rate and the reforming water flow rate are stepwise or The S / C value is changed continuously. That is, the raw material supply control means 50 reduces the supply amount of the raw fuel continuously or stepwise in conjunction with the decrease in the required amount of the refined reformed gas, and reforming water relative to the supply amount of the raw fuel. The supply amount is increased to increase the S / C value.

  As a result, even when the required amount of purified reformed gas decreases and the supply amount of raw fuel decreases, the supply amount of reforming water as a cooling medium does not fall below the required amount for cooling the second reactor. The second reactor 30 can be sufficiently cooled to prevent overheating of the second reactor 30, and the temperature of the second reactor 30 can be maintained within a temperature range suitable for the reaction. Can do. In addition, even if the temperature of the second reactor rises, it can be quickly cooled to the optimum temperature, so overshoot and undershoot are less likely to occur during cooling of the second reactor, and the temperature balance of the reformer is impaired. It will not be. As a result, even if the load on the fuel cell or the like is reduced and the required amount of the refined reformed gas is reduced, a refined reformed gas having a very low concentration of impurities such as CO can be obtained.

  The method for determining the S / C value that accompanies fluctuations in the required amount of purified reformed gas is not particularly limited, but the S / C value during rated operation and the required amount of purified reformed gas are minimized. And a method of determining the S / C value at the time of the operating load and performing proportional control or stepwise control of the S / C value according to the required amount of the refined reformed gas. For example, the required amount of purified reformed gas during rated operation is 100%, the S / C value at this time is 3.0, and the required amount of purified reformed gas at the minimum operating load is 30%. When the operation is performed with an S / C value of 3.5, it is possible to proportionally control the S / C as determined in the graph of FIG. 4 and determine the S / C value for each required amount of purified reformed gas. it can.

  A preferred embodiment of the operation method of the reformer of the present invention is that the raw material supply control means 50 controls the flow rate adjusting valves 45 and 46 for a predetermined time from when the required amount of the refined reformed gas falls below a preset lower limit value. After adjusting the degree of opening and closing, reducing the supply amount of reforming water relative to the supply amount of raw fuel from that during rated operation to lower the S / C value, and then stabilizing the temperature of the second reactor 30 In conjunction with a decrease in the required amount of purified reformed gas, the supply amount of raw fuel is reduced continuously or stepwise, and the supply amount of reforming water relative to the supply amount of raw fuel is increased. Increasing the C value.

  As described above, overheating of the second reactor 30 can be suppressed by increasing the S / C value during partial load operation. However, during partial load operation, if the amount of reformed water supplied to the first reactor 20 is increased and water vapor is excessively contained in the refined reformed gas, for example, it is used as a fuel gas supplied to the fuel cell. In such a case, water vapor condenses in the gas flow path inside the fuel cell and closes the flow path, which may impair the power generation capability of the fuel cell due to lack of gas.

  For this reason, depending on the use mode of the refined reformed gas, the S / C value cannot be increased without limit, in other words, the amount of reforming water supplied to the first reactor 20 cannot be increased without limit, so that partial load operation is performed. Sometimes, it is preferable to operate by shifting the temperature at which the second reactor 20 should be maintained within a range that does not impair the CO removal efficiency in the second reactor to a higher temperature range than during rated operation.

  However, the temperature rise of the second reactor 30 during the partial load operation is slow, and it may take a long time for the temperature to stabilize.

  Therefore, as described above, the S / C value is reduced within a preset range for a predetermined time after the required amount of the refined reformed gas falls below the preset lower limit value. The temperature rate is increased and the temperature of the second reactor 30 can be quickly increased. Then, after raising the temperature of the second reactor 30 in this way, the S / C value is increased continuously or stepwise in conjunction with a decrease in the required amount of purified reformed gas. Since the temperature increase rate of the two reactors 30 becomes slow and approaches a stabilized state, the temperature of the second reactor 30 can be quickly transferred to the optimum temperature.

  In the case where the S / C value is lowered, the lower limit value needs to be a value at which the hydrocarbons as the raw fuel are not coked in the first reactor 20. As a preferable example, as shown in FIG. 5, the S / C value at the rated operation and the S / C value at the operation load at which the required amount of the refined reformed gas is minimized are determined in advance. A method of operating by reducing the S / C value obtained according to the required amount of the quality gas by about 0.1 to 0.3 is mentioned. In addition, the operation time with the S / C value lowered is not particularly limited because it varies depending on the operation conditions and the device scale.

  In another preferred embodiment of the operation method of the reforming apparatus of the present invention, the opening / closing degree of the flow rate adjusting valves 45 and 46 is adjusted by the raw material supply control means 50 for a predetermined time from the start, and the supply amount of raw fuel is This is to reduce the S / C value by reducing the supply amount of the reforming water as compared with the rated operation.

  As described above, when the reformer is started, the temperature of the second reactor 30 may remain at a temperature lower than the temperature range that is considered to be stabilized during normal operation. The temperature of the two reactors 30 may not be stable.

  Therefore, the second reactor 30 can be quickly heated by operating with the S / C value lowered within a preset range from the rated operation for a predetermined time from the start as described above. The temperature of the second reactor 30 can be shifted to the temperature during steady operation.

  If the S / C value is lowered in an unstable state immediately after startup, CO may exist in the refined reformed gas, so when the temperature of the second reactor 30 approaches a stable state, It is preferable that the refined reformed gas discharged until the S / C value is returned to the rated state and the temperature of the second reactor 30 is stabilized is not supplied to a hydrogen consuming device such as a fuel cell.

(Test Example 1)
When the reforming apparatus shown in FIG. 1 is used and the reforming water amount is adjusted so that the S / C value becomes 3.0 with respect to the specified raw fuel flow rate during rated operation, the CO converter 31 is operated. The inner catalyst layer temperature could be maintained at around 350 ° C. on the inlet side 31a, and could be maintained around 200 ° C. on the outlet side 31b. At this time, the measured value of the first temperature sensor 51 was less than 100 ° C., and the measured value of the second temperature sensor 52 was about 150 ° C. That is, the reforming water in the raw material supply path 40 is not completely evaporated in the vicinity of the temperature sensor 51, and the reforming water has a function as a cooling medium. It can be seen that the reaction heat radiated can be cooled. The CO concentration in the reformed gas discharged from the CO converter 31 was 0.5% or less.

  On the other hand, when the load of the fuel cell power generator is at the minimum load, the required amount of purified reformed gas is about 30% of the rated operation (hereinafter referred to as “minimum load operation”). As in the rated operation, when the operation was performed by adjusting the supply amounts of raw fuel and reformed water so that the S / C value was 3.0, the catalyst layer temperature in the CO converter 31 was The temperature was about 400 ° C. at 31a and about 300 ° C. at the outlet side 31b. At this time, the measured value of the temperature sensor 51 was about 200 ° C., and the measured value of the temperature sensor 52 was about 240 ° C. That is, the reforming water in the raw material supply path 40 has already completely evaporated in the vicinity of the temperature sensor 51 and has lost its function as a cooling medium. For this reason, it turns out that the reaction heat of the CO converter 31 cannot be cooled in the case of the minimum load operation. The CO concentration of the reformed gas discharged from the CO converter 31 was about 1.0%, and the CO concentration increased nearly twice that of the rated operation.

  On the other hand, when the supply amounts of the raw fuel and the reforming water are adjusted so that the S / C value becomes 3.5 during the minimum load operation, the catalyst layer temperature in the CO converter 31 is The temperature was about 350 ° C. on the side 31a and about 200 ° C. on the outlet side 31b. At this time, the measured value of the temperature sensor 51 was about 98 ° C., and the measured value of the temperature sensor 52 was about 190 ° C. FIG. 2 is a chart showing the temperature change of the CO transformer 31 at the time of the minimum load, and FIG. 3 is a chart showing the temperature temperature change in the piping part 40b of the raw material supply path 40 arranged on the outer periphery of the CO transformer 31. .

  That is, the reforming water in the raw material supply path 40 is not completely evaporated in the vicinity where the temperature sensor 51 is disposed, and the reforming water functions as a cooling medium. It can be seen that the heat of reaction radiated can be cooled and kept at the optimum reaction temperature. At this time, the CO concentration of the reformed gas discharged from the CO converter 31 was the same as that during rated operation, and was 0.5% or less.

  Thus, according to the present invention, the S / C value is controlled to increase in conjunction with the decrease in the required amount of the refined reformed gas, so that the outer periphery of the second reactor 30 has fins, fans, etc. The second reactor 30 can be cooled to keep the second reactor 30 at the optimum reaction temperature without providing an external cooler. Even when the load on the fuel cell or the like is reduced and the required amount of the refined reformed gas is lowered, a refined reformed gas having a very low concentration of impurities such as CO can be obtained.

(Test Example 2)
In Test Example 1, the S / C value was set to 3.0 for the first 60 minutes during the minimum load operation. The measured value of the temperature sensor 51 during this time indicates 100 ° C. or higher, and the reforming water in the raw material supply path 40 has already completely evaporated in the vicinity of the temperature sensor 51 and functions as a cooling medium. Was lost.
Thereafter, when the S / C value was set to 3.2, the catalyst layer temperature in the CO converter 31 was 380 to 390 ° C. at the inlet side 31a at the time when about 60 minutes passed from the start of the lowest load operation, and the outlet The temperature on the side 31b was around 250 to 300 ° C., and the temperature of the CO transformer 31 was stabilized. At this time, the measured value of the first temperature sensor 51 was less than 100 ° C., and the measured value of the second temperature sensor 52 was about 150 ° C.
On the other hand, when the operation was continued with the S / C value set to 3.2 during the minimum load operation, the catalyst layer temperature in the CO converter 31 was about 120 minutes after the start of the minimum load operation. The temperature was 380 to 390 ° C. at the inlet side 31a and around 250 to 300 ° C. at the outlet side 31b, and the temperature of the CO transformer 31 was stabilized.
The transition of the temperature change on the inlet side of the CO transformer 31 is shown in FIG.
In this way, the S / C value is set to 3.0 for the first 60 minutes, and then the S / C value is set to 3.2, so that the temperature of the CO transformer 31 is quickly shifted to a stable temperature state. We were able to.

(Test Example 3)
The reformer shown in FIG. 1 was started up.
During the period from the start of start-up until 100 minutes have passed, the S / C value was set to 2.8, and then the S / C value was set to 3.0. As a result, the catalyst layer temperature in the CO converter 31 was about When 100 minutes passed, the temperature became stable at around 350 ° C. at the inlet side 31a and around 200 ° C. at the outlet side 31b.
On the other hand, when the S / C value was set to 3.0 from the start of startup, the catalyst layer temperature in the CO converter 31 was about 350 ° C. at the inlet side 31a when about 200 minutes had elapsed from the startup. The temperature became stable at around 31O <0> C on the side 31b.
The transition of the temperature change at the inlet side of the CO transformer 31 at this time is shown in FIG.
In this way, until 100 minutes have elapsed from the start of startup, the S / C value is set to 2.8, and then the S / C value is set to 3.0 so that the temperature of the CO transformer 31 can be quickly increased. It was possible to shift to a stable temperature state.

It is a schematic block diagram of the reformer of this invention. The figure showing the temperature change of the CO transformer at the time of minimum load operation is shown. The chart showing the temperature temperature change in the raw material supply path 40 is shown. It is a graph which shows the change of S / C value accompanying the fluctuation | variation of the request | requirement amount of refinement | purification reformed gas. It is a graph which shows the change of the S / C value at the time of the normal operation accompanying the fluctuation | variation of the request | requirement amount of refinement | purification reformed gas, and a S / C value fall operation. 10 is a chart showing a temperature change of a CO transformer in Test Example 2. 10 is a chart showing temperature changes of a CO transformer in Test Example 3.

Explanation of symbols

10: combustion chamber 20: first reactor 21: reformed gas flow path 25: partition wall 30: second reactor 31: CO converter 32: CO remover 33: air supply pipe 34: purified reformed gas delivery path 40 40a, 40b: reforming water-containing raw material supply path 41: raw material supply port 45, 46: flow rate adjusting valve 50: raw material supply control means

Claims (4)

A first reactor that generates a reformed gas by a steam reforming reaction of a raw material that is a mixture of hydrocarbons that are raw fuel and reformed water;
A second reactor connected to the first reactor and reducing the concentration of impurities contained in the reformed gas to obtain a refined reformed gas;
Supply of reformed water-containing raw material supply path for supplying the raw material to the first reactor, and supply of raw fuel and reformed water supplied to the reformed water- containing raw material supply path according to the required amount of the refined reformed gas A raw material supply control means for controlling the amount,
The reforming water-containing raw material supply path is connected to the first reactor through at least a heat exchange section with the second reactor,
The raw material supply control means has an S / C value expressing the supply amount of the reforming water per supply amount of the raw fuel supplied to the reforming water-containing raw material supply path in a molar ratio, as the refined reformed gas. A reformer characterized by being configured to increase continuously or stepwise in conjunction with a decrease in the required amount.   The raw material supply control means lowers the S / C value within a preset range from the rated operation for a predetermined time after the required amount of the refined reformed gas falls below a preset lower limit value. Then, the reformer is configured to increase continuously or stepwise in conjunction with a decrease in the required amount of the refined reformed gas.   3. The modified material according to claim 1, wherein the raw material supply control unit is configured to decrease the S / C value within a preset range from a rated operation for a predetermined time from the startup. Quality equipment.   The reformer according to any one of claims 1 to 3, wherein the second reactor is a CO converter and / or a CO remover.