JP2003206103A - Fuel reforming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel reforming apparatus in which the efficiency of a carbon monoxide removing equipment is improved. <P>SOLUTION: In the fuel reforming apparatus provided with a reforming reactor (5) for producing a reformed gas and CO removing equipment (6) for decreasing CO in the reformed gas to have a prescribed concentration, the CO removing equipment is provided with a 1st circulation pump (11) for circulating a coolant of a fixed quantity to the CO removing equipment, a means (15b) for detecting the reformed gas discharged from the CO removing equipment, a 1st flow passage (1a) for circulating the coolant discharged from the CO removing equipment to the CO removing equipment through the 1st circulation pump (11), a 2nd flow passage (1b) provided parallel to the 1st flow passage and provided with a radiator and a 1st three-way valve (12) for controlling the mixing ratio of the coolant from the 1st flow passage with the coolant from the 2nd flow passage in the coolant flowing in the CO removing equipment at a branch point where the 1st flow passage and the 2nd flow passage are branched. The 1st three-way valve controls the mixing ratio so that the temperature of the reformed gas discharged from the CO removing equipment becomes a prescribed temperature. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel reformer, and more particularly to a method for cooling a fuel reformer provided in a fuel cell system.

[0002]

2. Description of the Related Art Regarding a method of cooling a fuel reformer, for example, Japanese Patent Laid-Open No. 10-302824 discloses cooling a carbon monoxide (hereinafter, simply referred to as CO) remover which is a structure of the fuel reformer. The technology regarding is disclosed.

In the above-mentioned publication, a cooling pipe is provided inside the CO remover (reactor 6), one end of the cooling pipe is connected to a cooling water tank via a circulation pump, and the other end is connected via a radiator. The cooling water in the cooling water tank circulates in the cooling pipe in the CO remover by the action of the circulation pump to cool the CO remover, and the heated cooling water is cooled in the radiator. Then, the configuration for returning to the cooling water tank is disclosed. Therefore, the cooling water flows through the CO remover to absorb the heat generated by the CO selective oxidation reaction in the reformed gas, thereby reducing the CO
The temperature rise in the remover can be suppressed.

Further, Japanese Patent Laid-Open No. 07-185303 discloses a catalyst laminate in which a catalyst layer carrying a selective catalyst and a cooling layer through which cooling water flows are alternately laminated, and a selective oxidation catalyst in a box-shaped casing. Disclosed is a CO removing device in which a catalyst packed body filled with is bonded via a mesh plate in the flow direction of the reformed gas, and the catalyst laminate can be cooled.

Further, in Japanese Patent Laid-Open No. 2000-72403, a fuel provided with a means for cooling the reformed gas is provided between the reformed gas generation section and a CO remover for removing CO contained in the reformed gas. A battery system is disclosed, which has a configuration for appropriately controlling the temperature of the reformed gas supplied to the CO remover.

[0006]

However, in the technique described in Japanese Patent Laid-Open No. 10-302824, the cooling water cooled by the radiator flows into the CO remover from the tank, so the CO remover inlet Temperature becomes low, the temperature difference from the outlet temperature becomes large, the temperature of the catalyst in the CO remover does not become uniform, the area where the activation temperature is not reached increases, and the overall CO removal efficiency decreases. Is a problem.

Further, in the technique disclosed in Japanese Patent Laid-Open No. 07-185303, it is possible to cool the catalyst laminate having a strong CO selective oxidation reaction, but the catalyst packing located downstream has no cooling means. Although the CO selective oxidation reaction itself is small, the catalyst temperature of the catalyst packing may exceed the activation temperature range of the catalyst.

In the technique of Japanese Patent Laid-Open No. 2000-72403, the temperature of the reformed gas is controlled by controlling the flow rate of the cooling water (refrigerant), so the temperature difference between the inlet and outlet of the cooling means is not minimized, The temperature of the reformed gas at the outlet of the cooling means becomes non-uniform, and the performance efficiency of the CO remover into which this reformed gas is introduced decreases.

That is, in any of the conventional control methods so far, the temperature inside the CO remover cannot be accurately controlled within the activation temperature range of the catalyst, and for example, the activation temperature becomes the downstream side of the CO remover. When the temperature is controlled to 1, the CO selective oxidation reaction does not occur on the upstream side, and the CO removal performance cannot be sufficiently exhibited. When the temperature is controlled so that the catalyst activation temperature is on the inlet side, the catalyst temperature on the downstream side exceeds the activation temperature, and a reverse shift reaction occurs and CO cannot be removed or generated in the reforming reactor. Hydrogen is burned, resulting in a reduction in reforming efficiency.

The temperature control of the conventional CO remover will be described. As means for controlling the temperature, there are one for controlling the flow rate of the cooling water and one for controlling the temperature of the cooling water at the inlet of the CO remover.

When the flow rate of the cooling water is controlled according to the load of the circulation pump, C
The cooling water temperature at the inlet of the O remover and the cooling water temperature at the outlet always have a constant temperature difference. Therefore, as described above, depending on the setting of the control temperature, the removal of CO is not promoted on the inlet side, or conversely, the reverse shift reaction occurs on the outlet side.

On the other hand, when controlling the temperature of the cooling water at the inlet of the CO remover, for example, a heat exchanger is installed upstream of the CO remover and a thermostat is provided at the outlet of the CO remover.
When controlling the temperature of the cooling water at the inlet of the O remover, if the temperature of the catalyst on the downstream side is controlled to reach the activation temperature when the load is high, the temperature inside the remover is reduced when the load of the CO remover is low. There is a possibility that CO cannot be removed because the activation temperature is not reached.

The CO eliminator selectively oxidizes and removes CO contained in the reformed gas when the selective oxidation catalyst reaches the activation temperature. At this time, the catalyst activation temperature is within a predetermined temperature range. However, the above-mentioned conventional technique cannot properly control the temperature of the catalyst in the CO remover in such a temperature range.

In view of the above problems, the present invention proposes a fuel reformer capable of controlling the contained selective oxidation catalyst in the CO remover within an activation temperature range.

[0015]

According to a first aspect of the invention, the carbon monoxide remover has a function of exchanging heat with a reformed gas, and the refrigerant is circulated in a fixed amount in the carbon monoxide remover. First circulation pump, means for detecting the temperature of the reformed gas or the refrigerant discharged from the carbon monoxide remover, and the refrigerant discharged from the carbon monoxide remover through the first circulation pump. A first flow path that circulates in the carbon oxide remover, a second flow path that is provided in parallel with the first flow path and that includes a radiator, and a branch point between the first flow path and the second flow path, A first three-way valve for controlling a mixing ratio of the refrigerant flowing into the carbon monoxide remover from the first flow passage and the refrigerant from the second flow passage, wherein the first three-way valve is provided The mixing ratio is controlled so that the temperature of the reformed gas or the temperature of the refrigerant discharged from the carbon remover becomes a predetermined temperature.

In a second aspect based on the first aspect, the heat exchanger for cooling the reformed gas, the second circulation pump for circulating the refrigerant through the heat exchanger, and the heat exchanger for discharging the reformed gas are discharged from the heat exchanger. Means for detecting the temperature of the reformed gas or the refrigerant, a third passage for circulating the refrigerant discharged from the heat exchanger to the heat exchanger, and a radiator provided by bypassing the third passage. And a refrigerant from the third channel and a refrigerant from the fourth channel of the refrigerant flowing into the heat exchanger, at a downstream branch point of the third channel and the fourth channel. And a second three-way valve for controlling the mixing ratio of the second circulation pump, the second circulation pump is operated at a predetermined flow rate, and the second three-way valve causes the temperature of the refrigerant discharged from the heat exchanger to reach a predetermined temperature. Control the mixing ratio.

In a third aspect based on the first or second aspect, when the operating load of the CO remover is maximum, the temperature of the catalyst contained in the CO remover becomes the activation temperature.
The first circulation pump is operated at the maximum rated flow rate, and the mixing ratio of the first three-way valve is controlled.

In a fourth aspect based on the second or third aspect, when the operating load of the heat exchanger is maximum, the temperature of the refrigerant discharged from the heat exchanger becomes an allowable temperature. The circulation pump is operated at the maximum rated flow rate, and the mixing ratio of the second three-way valve is controlled.

In a fifth aspect based on the first aspect, the heat exchanger for cooling the reformed gas, the second circulation pump for circulating the refrigerant through the heat exchanger, and the exhaust gas discharged from the heat exchanger. Means for detecting the temperature of the reformed gas or the refrigerant, a third flow path for circulating the refrigerant discharged from the heat exchanger to the heat exchanger, and a third flow passage for connecting the first three-way valve and the second three-way valve. 5
A flow path, a third circulation pump installed in the second flow path, a sixth flow path that connects the second flow path and the third flow path, and a seventh flow that connects the second flow path And a passage for adjusting the flow rate of the refrigerant flowing into the radiator by the third circulation pump, and controlling the refrigerant at the radiator outlet to a predetermined temperature.

In a sixth aspect based on the first aspect, first temperature difference detecting means for detecting the temperature of the refrigerant at the inlet / outlet of the CO remover and detecting the temperature difference, and the outlet of the first radiator. And a second temperature difference detecting means for detecting a temperature difference between the refrigerant temperature at the outlet of the first radiator and the refrigerant temperature at the outlet of the CO remover, and a first temperature difference detecting means. And a circulation rate calculating means for calculating the mixing rate of the refrigerant to be supplied to the CO remover based on the output of the second temperature difference detecting means, and the first mixing rate is calculated by the circulation rate calculating means. Control the three-way valve.

In a seventh aspect based on the second aspect, the fourth temperature difference detecting means for detecting the temperature of the refrigerant at the inlet and outlet of the heat exchanger and the temperature difference between the refrigerant temperature and the outlet of the second radiator. Means for detecting the refrigerant temperature at the second heat radiator, a fifth temperature difference detecting means for detecting a temperature difference between the refrigerant temperature at the second radiator outlet and the refrigerant temperature at the heat exchanger outlet, and a fourth temperature difference detecting means. And second circulation rate calculation means for calculating the mixing rate of the refrigerant supplied to the heat exchanger based on the output of the fifth temperature difference detection means,
The second three-way valve is controlled so that the mixing rate calculated by the second circulation rate calculating means is obtained.

In an eighth aspect based on the first aspect, first temperature difference detecting means for detecting the temperature of the refrigerant at the inlet / outlet of the CO remover and detecting the temperature difference, and the outlet of the first radiator. And a second temperature difference detecting means for detecting a temperature difference between the refrigerant temperature at the outlet of the first radiator and the refrigerant temperature at the outlet of the CO remover, and a first temperature difference detecting means. And a circulation rate calculating means for calculating the mixing rate of the refrigerant supplied to the CO remover based on the output of the second temperature difference detecting means, and a temperature difference between the temperature of the refrigerant at the outlet of the CO remover and its target temperature. The third temperature difference detecting means, the PID control calculating means for calculating the correction rate of the mixing rate based on the temperature difference calculated by the third temperature difference detecting means, and the mixing rate calculated by the circulation rate calculating means. The correction factors calculated by the PID control calculation means are added, and the correction mixture is added. And an adding means for calculating a controls the first three-way valve so that the calculated corrected mixing ratio in the adding means.

In a ninth aspect based on the second or eighth aspect, fourth temperature difference detecting means for detecting the temperature of the refrigerant at the inlet / outlet of the heat exchanger and detecting the temperature difference, and the second radiator. Means for detecting the refrigerant temperature at the outlet of the heat exchanger, a fifth temperature difference detecting means for detecting a temperature difference between the refrigerant temperature at the second radiator outlet and the refrigerant temperature at the heat exchanger outlet, and a fourth temperature difference. Second circulation rate calculating means for calculating the mixing rate of the refrigerant supplied to the heat exchanger based on the outputs of the detecting means and the fifth temperature difference detecting means, and the temperature of the refrigerant at the outlet of the heat exchanger and its target temperature. And a sixth temperature difference detecting means for calculating a temperature difference between
Second PID control calculation means for calculating a correction rate of the mixing rate based on the temperature difference calculated by the temperature difference detection means, and the correction rate calculated by the second PID control calculation means are added to the mixing rate calculated by the circulation rate calculation means. And a second adding means for calculating the corrected mixing ratio, and the second three-way valve is controlled so that the corrected mixing ratio calculated by the second adding means is obtained.

[0024]

According to the first and third aspects of the present invention, by operating the circulation pump at a predetermined flow rate, the flow path of the refrigerant flowing through the CO remover is divided into the first flow path and the second flow path including the radiator. Separately, a three-way valve is installed at the branch point of the first flow path and the second flow path, and the refrigerant from the CO remover flowing through the first flow path and the refrigerant cooled by the radiator flowing through the second flow path are separated. The reformed gas or the refrigerant discharged from the CO remover is mixed by a three-way valve based on a mixing ratio at which the temperature of the reformed gas or the temperature of the refrigerant reaches a predetermined temperature, and the mixed gas is introduced into the CO remover.

Therefore, the selective oxidation catalyst installed in the CO remover can be accurately controlled to a predetermined temperature (for example, the upper limit temperature of the activation temperature).

In the second and fourth inventions, the same structure as the first and third inventions is applied to the heat exchanger for cooling the reformed gas, so that the temperature of the reformed gas discharged from the heat exchanger is changed. It can be controlled properly.

According to the fifth aspect of the invention, the radiator for cooling the refrigerant flowing through the heat exchanger and the radiator for cooling the refrigerant flowing through the CO remover are shared, so that the structure is simplified and the cost of the apparatus is low. Can be realized.

In the sixth and seventh inventions, the temperature difference between the respective parts is calculated, the mixing ratio is obtained based on the calculation result, and the three-way valve is controlled. Therefore, the load change which changes depending on the temperature is promptly converted into the mixing ratio. Since conversion is possible, it is possible to perform temperature control with good responsiveness.

In the eighth and ninth aspects of the invention, the temperature difference between the respective parts is calculated, the mixing ratio is obtained based on the calculation result, and the calculated mixing ratio is corrected based on the target temperature before controlling the three-way valve. Since the load change that changes according to the temperature can be quickly converted into the mixing ratio, it is possible to perform the temperature control with good responsiveness and high accuracy.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION A fuel reforming apparatus of the present invention will be described below with reference to the drawings. FIG. 1 is a fuel cell system using the fuel reforming apparatus of the present invention. Air from a blower 1 as an air supply source is supplied to a reforming reactor 3 via a flow control valve 2. Fuel (for example, hydrocarbon fuel and water) is supplied to the reforming reactor 3 in addition to air to generate a hydrogen-rich reformed gas, which is supplied to the heat exchanger 5 located downstream. In the heat exchanger 5, the reformed gas is introduced into the CO remover 6 after being adjusted to a temperature at which the selective oxidation catalyst contained in the CO remover 6 installed downstream of the heat exchanger 5 reaches an activation temperature. It The CO remover 6 carries Pt or Ru as a selective oxidation catalyst, and selectively oxidizes and removes CO contained in the reformed gas when the catalyst reaches the activation temperature. The activation temperature is
As shown in FIG. 2, it is given as a temperature range of around 150 ° C., and the temperature inside the CO remover 6 is maintained within this temperature range regardless of the load, from the viewpoint of removing CO in the reformed gas. From desirable.

Air from the blower 1 is supplied to the CO remover 6 via the flow control valve 4. To selectively oxidize the air and the CO contained in the supplied reformed gas in an amount of about 3.5% by the action of the catalyst of the CO remover 6 to reduce the CO concentration in the reformed gas to 40 ppm or less. You can Therefore, the reformed gas having a low CO concentration is used as the CO remover 6
Since the fuel cell stack 7 is supplied to the fuel cell stack 7, CO poisoning of a single cell catalyst, for example, a Pt-based catalyst that constitutes the fuel cell stack 7 can be suppressed.

In the fuel cell stack 7, low CO
A reformed gas rich in hydrogen at a concentration is supplied, and air is supplied from the blower 1 to the air electrode with the flow rate controlled by the flow rate control valve 8 to generate power. The exhaust gas (exhaust hydrogen and exhaust air) discharged from the fuel cell stack 7 is sent to the combustor 9 and mixed with the air from the blower 1 supplied through the flow rate control valve 10 to be burned to the atmosphere. Is released.

The above is the main structure of the fuel cell system, and the details of the fuel reformer 100, which mainly has the reforming reactor 3, the heat exchanger 5, and the CO remover 6, will be described below.

First, the CO remover 6 is constructed by laminating a cooling layer through which a refrigerant (for example, water) for controlling the temperature thereof flows and a catalyst layer through which a reformed gas flows. The refrigerant supplied to the cooling layer is supplied from the first circulation pump 11, at which time the first circulation pump 11 operates at the maximum rated capacity (flow rate) and supplies the cooling layer with the maximum flow rate. Refrigerant is CO
The heat generated by the CO selective oxidation reaction of the remover 6 is absorbed, and the first
It is sent to the first radiator 13 via the first three-way valve 12 via the flow passage 1a and the second flow passage 1b branched from the first flow passage 1a. The coolant cooled by the first radiator 13 is the second flow path 1b.
Through the first three-way valve 12.

The first three-way valve 12 supplies the low temperature refrigerant cooled by passing through the first radiator 13 and the high temperature refrigerant still discharged from the CO remover 6 to the set temperature of the catalyst of the CO remover 6. The CO remover 6 is mixed at a predetermined ratio (mixing ratio) according to
Controlled by the controller 30. The temperature of the reformed gas downstream of the CO remover is input to the controller 30 from the temperature detector 14, and the temperatures of the refrigerants upstream and downstream of the CO remover 6 are input from the temperature detectors 15a and 15b. Based on this, the setting of the first three-way valve 12 is determined.

A reservoir tank 16 is installed branching from the first flow path 1a communicating with the first three-way valve 12 from the CO remover 6 to absorb thermal expansion of the refrigerant and remove bubbles in the refrigerant. To be done.

The controller 30 uses the CO
The temperature of the reformed gas downstream of the remover is from the temperature detector 14, or the temperature of the refrigerant downstream of the CO remover 6 is from the temperature detector 15b.
Input from the first radiator 1 based on these detected values.
The mixing ratio and the circulation rate (mixing rate) of the refrigerant cooled in step 3 and the refrigerant that has been discharged from the CO remover 6 are such that the temperature of the reformed gas or the refrigerant discharged from the CO remover 6 is a predetermined temperature. And the opening degree of the first three-way valve 12 is controlled so as to obtain the calculated circulation rate. At this time, the predetermined temperature of the reformed gas or the refrigerant is feedback-controlled so as to be, for example, 150 ° C. which is the activation temperature of the catalyst.

The heat exchanger 5 installed between the reforming reactor 3 and the CO remover 6 cools the high temperature reformed gas introduced from the reforming reactor 3 to a predetermined temperature. That is, the refrigerant discharged from the heat exchanger 5 into which the reformed gas is introduced passes through the third flow passage 2a, the second three-way valve 18 and the fourth flow passage 2b branched from the third flow passage 2a, and then the second radiator. Sent to 19.
The refrigerant sent to the second radiator 19 is deprived of heat to become a low temperature, and is sent to the second three-way valve 18. For the second three-way valve 1
The refrigerant sent directly to 8 maintains a high temperature. The data of the temperature detector 20 that detects the temperature of the reformed gas downstream of the heat exchanger 5 or the data of the temperature detector 21 that detects the temperature of the refrigerant downstream of the heat exchanger 5 is input to the controller 31 and the controller 31. However, so that the temperature of the reformed gas or the refrigerant downstream of the heat exchanger 5 reaches a predetermined temperature, the low temperature refrigerant that has passed through the second radiator 19 and is cooled from the heat exchanger 5 to the second
Calculate the circulation rate with the high temperature refrigerant sent to the three-way valve 18,
Based on the calculated circulation rate, the controller 31
The setting of the second three-way valve 18 is controlled. At this time, the predetermined temperature of the reformed gas or the refrigerant is feedback-controlled so as to be 140 ° C., for example. This is a CO located downstream
This is a temperature that is set in consideration of the heating amount by the selective oxidation reaction so that the temperature of the catalyst of the CO remover 6 becomes 150 ° C. when the predetermined temperature in the remover 6 is assumed to be the activation temperature of 150 ° C. A second circulation pump 22 is installed between the second three-way valve 18 and the heat exchanger 5.

Therefore, the first and second three-way valves 12, 18
Is used to mix the refrigerant directly sent from the CO remover 6 or the heat exchanger 5 with the refrigerant cooled through the first and second radiators 13 and 19, and the circulation rate is adjusted to the CO remover 6 or the heat exchanger. The temperature of the refrigerant or reformed gas discharged from 5,
It is calculated based on the target temperature of the reformed gas or the refrigerant, and the controllers 30 and 31 control the opening degrees of the first and second three-way valves 13 and 18 so as to achieve this circulation rate. By controlling in this way, as shown in FIG. 3, the catalyst temperature on the outlet side of the CO remover 6 can always be maintained at the activation temperature regardless of the load factor, while the catalyst temperature on the inlet side is When the load is low, the temperature is almost the same as that on the outlet side, that is, the catalyst activation temperature, and the higher the load is, the lower the temperature of the inflowing refrigerant is. Similarly, the temperature of the refrigerant on the outlet side of the heat exchanger 5 can be controlled to be constant. As described above, in the CO remover 6 of the present invention, it is possible to control to a narrow temperature range on the upper side of the catalyst activation temperature where the CO selectivity with a low load is the highest.

However, when the temperature difference of the refrigerant at the inlet and outlet of the CO remover 6 when controlling the flow rate of the refrigerant shown in FIG. 4 or the refrigerant temperature at the inlet of the CO remover 6 shown in FIG. 5 is controlled Compared with the temperature difference between the inlet and outlet of the refrigerant of the present invention, in the present invention, the activation temperature of the catalyst is always reached on the outlet side, and the activation temperature on the inlet side can also be reached from low load to medium load. Clearly from control method CO
The removal efficiency is improved. Furthermore, since the temperature of the refrigerant on the outlet side of the CO remover 6 can be controlled to be constant, the temperature of the reformed gas discharged from the CO remover 6 can always be kept constant, which contributes to the improvement of power generation efficiency.

Further, as shown in FIG. 2, the higher the load of the CO remover 6, the more the CO selective oxidation reaction is promoted, so the amount of input heat for raising the temperature of the CO remover 6 increases, and the CO remover 6 is overheated. There is a risk that Therefore, in order to adjust the temperature of the CO remover 6, the refrigerant that passes through the first radiator 13 and has a high proportion of the cooled refrigerant is supplied to the CO remover 6, so that C
The inlet side of the O remover 6 has a low temperature, and as a result, the temperature difference between the inlet side catalyst and the outlet side catalyst becomes maximum. However, as shown in FIG. 2, if the temperature can be maintained in the catalyst activation temperature range, the decrease in CO selectivity can be suppressed. Therefore, the flow rate of the refrigerant is determined so as to maintain the temperature at the maximum load, and the flow rate at this time is 1st circulation pump 11 used as the maximum rated capacity of 1 circulation pump 11
To use. By operating the first circulation pump 11 used in this manner at the maximum rated capacity when the CO remover 6 is at maximum load, the active temperature range of the catalyst can be maintained even when the load factor is maximum, and when the CO load is low, the CO Highest selectivity,
It can be controlled in the temperature range where the temperature difference is small.

The second embodiment shown in FIG. 6 differs from the first embodiment shown in FIG. 1 in that the first radiator 13 is replaced by the heat exchanger 5.
And the CO remover 6 are commonly used.

The refrigerant discharged from the heat exchanger 5 passes through the second three-way valve 18 and returns to the heat exchanger 5.
It is supplied to the flow channel 2a and the sixth flow channel 2b which branches from the third flow channel 2a and communicates with the second flow channel 1b. A third circulation pump and a first radiator 13 are installed in series in the second flow path 1b. A fifth branch that branches from the second flow path 1b downstream of the first radiator 13 and communicates with the first three-way valve 12 and the second three-way valve 18.
The flow path 2c is connected, and the fifth flow path 2c is further provided with a seventh flow path 2d that communicates with the second flow path 1b upstream of the first radiator 13 from its branch point.

With this structure, the refrigerant cooled by the first radiator 13 is pumped to the cooling system of the heat exchanger 5 and the cooling system of the CO remover 6 by the action of the third circulation pump 23. , Part of which flows through the seventh flow passage 2d that communicates between the second flow passages 1b with the first radiator 13 interposed therebetween, and returns to the third circulation pump 23.

Second channel 1b, fifth channel 2c, and seventh channel 2
A temperature detector 24 that detects the temperature of the refrigerant downstream of the first radiator 13 is installed at the branch with d, and this output is input to the controller 32. The controller 32 controls the driving force or the rotational speed of the third circulation pump 23 based on this data, controls the temperature of the refrigerant flowing out from the first radiator 13, and consequently controls the heat exchanger 5 and the CO remover 6. The temperature of the refrigerant supplied to the first three-way valve 12 and the second three-way valve 18 is controlled. For example, this temperature is set to 80 ° C., which is lower than the set temperatures of the heat exchanger 5 and the CO remover 6.

With such a structure, the first radiator 13 can be used for both the cooling of the heat exchanger 5 and the cooling of the CO remover 6, which simplifies the structure and serves as a fuel reformer. The price can be reduced.

In FIG. 7, the controller 30 uses the CO remover 6
FIG. 3 is a block diagram for explaining the control content for controlling the refrigerant temperature in order to control the catalyst temperature to a set temperature. It is also possible to use it for controlling the temperature of the refrigerant for controlling the temperature of the reformed gas in the heat exchanger 5.

The first temperature difference detecting means 43 is the temperature detector 1
Refrigerant temperature T1 downstream of the CO remover 6 detected from 5b
And the refrigerant temperature T2 at the inlet of the CO remover 6 detected by the temperature detector 15a, the temperature difference ΔTi = T1-T
Calculate 2.

The second temperature difference detecting means 44 is the temperature detector 1
Refrigerant temperature T1 downstream of the CO remover 6 detected from 5b
From the refrigerant temperature T3 downstream of the first radiator 13 detected by the temperature detector 24, the temperature difference ΔTo = T1-T3.
To calculate.

The first circulation rate calculating means 46 is means for calculating the circulation rate R, and the calculation of the circulation rate R will be described below.

Now, assuming that the absorbed heat quantity absorbed by the refrigerant in the CO remover 6 is Qpi, the absorbed heat quantity Qpi is obtained by the absorbed heat quantity Qpi = ΔTi × specific heat K × the refrigerant flow rate Qwt flowing through the CO remover 6.

The amount of heat radiated by the first radiator 13 is Q.
The po is calculated by the heat radiation amount Qpo = ΔTo × specific heat K × the refrigerant flow rate Qws flowing through the first radiator 13.

Now, assuming that the absorbed heat quantity Qpi = radiation heat quantity Qpo, the circulation rate R of the low-temperature refrigerant passing through the first radiator 13 can be obtained by the circulation rate R = ΔTi / ΔTo = Qwt / Qws.

Target circulation rate Rff = ΔT1 / ΔTo Becomes

The valve opening degree converting means 48 determines the valve opening degree corresponding to the target circulation rate Rff based on the relationship between the circulation rate R and the opening degree of the first three-way valve 12 which is obtained in advance as shown in FIG. It is calculated and the opening degree of the first three-way valve 12 is controlled.

As described in the first embodiment, the first circulation pump 11 is operated in the full load state, and the maximum flow rate of the refrigerant is supplied to the CO remover 6. Therefore, FIG.
As shown in, the temperature difference ΔTi can be made smaller as the load factor of the CO remover 6 is lower, and the heat load change can be immediately converted into the circulation rate R, so that the temperature control of the CO remover 6 with high response is possible. Becomes

In FIG. 8, the controller 30 uses the CO remover 6
FIG. 7 is another block diagram for explaining the control content for controlling the refrigerant temperature in order to control the catalyst temperature to the set temperature.
It is also possible to use it for controlling the temperature of the refrigerant for controlling the temperature of the reformed gas in the heat exchanger 5.

The first temperature difference detecting means 43 is the temperature detector 1
Refrigerant temperature T1 downstream of the CO remover 6 detected from 5b
And the refrigerant temperature T2 at the inlet of the CO remover 6 detected by the temperature detector 15a, the temperature difference ΔTi = T1-T
Calculate 2.

The second temperature detecting means 44 is the temperature detector 15
Refrigerant temperature T1 downstream of the CO remover 6 detected from b
From the refrigerant temperature T3 downstream of the first radiator 13 detected by the temperature detector 24, the temperature difference ΔTo = T1-T3.
To calculate.

The circulation rate calculating means 46 calculates the target circulation rate Rff = ΔTi / ΔTo in the same manner as described with reference to FIG.

The third temperature difference detecting means 42 has a set temperature Tr.
And the temperature difference ΔTfb = Tr−T1 between the refrigerant temperature T1 and the refrigerant temperature T1 are calculated.

The PID control calculation means 45 determines the temperature difference ΔTf.
The correction amount Rfb is calculated based on b and the control gain.

The adding means 27 calculates the corrected circulation rate R by adding the target circulation rate Rff and the correction amount Rfb.

The valve opening degree converting means 48 determines the valve opening degree corresponding to the corrected circulation rate R based on the relationship between the circulation rate R and the opening degree of the first three-way valve 12 which is obtained in advance as shown in FIG. It is calculated and the opening degree of the first three-way valve 12 is controlled.

As described in the first embodiment, the first circulation pump 11 is operated in the full load state, and the maximum flow rate of the refrigerant is supplied to the CO remover 6. Therefore, FIG.
As shown in, the temperature difference ΔTi can be made smaller as the load factor of the CO remover 6 is lower, and the heat load change can be immediately converted into the circulation rate R. Therefore, the temperature of the CO remover 6 with high response and high accuracy can be obtained. It becomes possible to control.

FIG. 10 shows an example of a specific structure of the CO removing device 6, in which the refrigerant layer in which the refrigerant flows and the reformed gas flow path in which the reformed gas flows are orthogonal (in the flow direction). So that they are stacked alternately. here,
In the region 25 where the reformed gas and the refrigerant first exchange heat, C
It is configured not to carry an O selective oxidation catalyst. With such a configuration, as shown in FIG. 11, the temperature of the refrigerant flowing through the refrigerant passage F on the upstream side in the flow direction of the reformed gas is lower than that of the refrigerant flowing through the refrigerant passage R on the downstream side by CO. Since the amount of heat generated by the selective oxidation reaction is large, the rate of temperature increase of the refrigerant is high. However, by limiting the catalyst carrying area as described above, it is possible to prevent the refrigerant temperature from overheating at the outlet of the refrigerant channel F. It can be prevented. Therefore, the amount of heat generated by the selective oxidation reaction in the CO remover 6 can be made uniform.

FIG. 12 shows an example of another specific structure of the CO removing device 6. In the CO removing device 6 having a laminated structure as shown in FIG. 10, as shown in FIG. So that the flow rate distribution of the refrigerant introduced into the refrigerant increases toward the reformed gas inlet side.
The cross-sectional area of the shape is larger on the upstream side of the reformed gas. By allowing more refrigerant to flow toward the reformed gas upstream side in this way, the temperature rise on the outlet side of the refrigerant on the reformed gas upstream side, where the selective oxidation reaction is promoted, is suppressed, and inside the CO remover 6. The temperature distribution of the refrigerant can be made uniform.

The configuration of the CO remover 6 shown in FIG. 14 does not depend on the shape of the inlet portion such as the collector for distribution of the flow rate, but rather on the inlet portion a resistor such as a porous body or a wire which obstructs the flow of the refrigerant. It is changed by installing 27.
Based on the same concept as in FIG. 12, the resistor is installed so that the resistance to the flow of the refrigerant increases toward the downstream side in the flow direction of the reformed gas. By allowing more refrigerant to flow toward the reformed gas upstream side in this way, the temperature rise on the outlet side of the refrigerant on the reformed gas upstream side, where the selective oxidation reaction is promoted, is suppressed, and inside the CO remover 6. The temperature distribution of the refrigerant can be made uniform.

The configuration of the CO remover 6 shown in FIGS. 15 and 16 is such that the distribution of the flow rate of the refrigerant is controlled by the shape of the refrigerant passage. That is, in the structure shown in FIG. 15, the length of the refrigerant passage from the time when the refrigerant flows into the refrigerant passage to the time when the refrigerant flows out is set to be longer by using the closing plate 28 toward the downstream side in the flow direction of the reformed gas. This increases the flow path resistance. By allowing more refrigerant to flow toward the reformed gas upstream side in this way, the temperature rise on the outlet side of the refrigerant on the reformed gas upstream side, where the selective oxidation reaction is promoted, is suppressed, and inside the CO remover 6. The temperature distribution of the refrigerant can be made uniform.

The present invention is not limited to the above-mentioned embodiments, and it is obvious that various modifications can be made within the scope of the technical idea of the present invention.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a fuel cell system to which a fuel reforming device of the present invention is applied.

FIG. 2 is a diagram showing a relationship between refrigerant temperature and CO selectivity.

FIG. 3 is a diagram showing a relationship between a load factor and a refrigerant temperature at a CO remover inlet / outlet portion according to the present invention.

FIG. 4 is a diagram showing the relationship between the load factor and the refrigerant temperature at the CO remover inlet / outlet in the case of refrigerant temperature control.

FIG. 5: Load factor and C in case of inlet temperature control of CO remover
It is a figure which shows the relationship with the refrigerant temperature in an O remover inlet-outlet part.

FIG. 6 is a diagram showing a configuration of a fuel cell system of a second embodiment to which a fuel reformer is applied.

FIG. 7 is a control block diagram for explaining a cooling control method for a CO remover.

FIG. 8 is a control block diagram for explaining another cooling control method for the CO remover.

FIG. 9 is a diagram showing the relationship between the opening degree of a three-way valve and the mixing ratio.

FIG. 10 is an example showing a specific configuration of a CO remover to which the present invention is applied.

FIG. 11 is a diagram showing a change in refrigerant temperature due to a difference in position in the CO remover.

FIG. 12 is an example showing a specific configuration of another CO remover to which the present invention is applied.

FIG. 13 is a diagram showing a relationship between a refrigerant flow path of the CO remover and a refrigerant mixing ratio.

FIG. 14 is an example showing a specific configuration of another CO remover to which the present invention is applied.

FIG. 15 is an example showing a specific configuration of another CO remover to which the present invention is applied.

16 is a cross-sectional view showing a cross section AA in FIG.

[Explanation of symbols]

3 reforming reactor 5 heat exchanger 6 CO remover 7 Fuel cell stack 12 First three-way valve 13 First radiator 18 second three-way valve 19 Second radiator

Claims (9)

[Claims] 1. A reforming reactor that reacts the supplied raw fuel with air to produce reformed gas, and monoxide that reduces carbon monoxide contained in the reformed gas to a predetermined concentration by a selective oxidation reaction. In a fuel reforming apparatus comprising a carbon remover, the carbon monoxide remover has a function of exchanging heat with a reformed gas, and a first for quantitatively circulating a refrigerant in the carbon monoxide remover. 1 circulation pump, means for detecting the temperature of the reformed gas or the refrigerant discharged from the carbon monoxide remover, and the refrigerant discharged from the carbon monoxide remover through the first circulation pump carbon monoxide A first flow path that circulates in the remover, a second flow path that is provided in parallel with the first flow path and that includes a radiator, and a monoxide at the branch point of the first flow path and the second flow path. Refrigerant from the first flow path and refrigerant from the second flow path of the refrigerant flowing into the carbon remover And a first three-way valve for controlling the mixing rate with the first three-way valve such that the temperature of the reformed gas discharged from the carbon monoxide remover or the temperature of the refrigerant reaches a predetermined temperature. The fuel reformer is characterized by controlling the. 2. A heat exchanger for cooling the reformed gas, a second circulation pump for circulating a refrigerant through the heat exchanger, and a temperature of the reformed gas or the refrigerant discharged from the heat exchanger. Means, a third flow path for circulating the refrigerant discharged from the heat exchanger to the heat exchanger, a fourth flow path that bypasses the third flow path, and includes a radiator, A second three-way valve for controlling the mixing ratio of the refrigerant flowing from the third flow path and the refrigerant flowing from the fourth flow path into the heat exchanger at the downstream branch point of the third flow path and the fourth flow path. The second circulation pump is operated at a predetermined flow rate, and the second three-way valve controls the mixing ratio so that the temperature of the refrigerant discharged from the heat exchanger reaches a predetermined temperature. The fuel reformer according to claim 1. 3. The maximum rated flow rate of the first circulation pump is set so that the temperature of the catalyst contained in the carbon monoxide remover becomes an activation temperature when the operating load of the carbon monoxide remover is maximum. The fuel reformer according to claim 1 or 2, wherein the fuel reformer controls the mixing ratio of the first three-way valve while operating at 1. 4. The second circulation pump is operated at the maximum rated flow rate so that the temperature of the refrigerant discharged from the heat exchanger reaches an allowable temperature when the operating load of the heat exchanger is maximum, and The fuel reformer according to claim 2 or 3, wherein a mixing ratio of the second three-way valve is controlled. 5. A heat exchanger for cooling the reformed gas, a second circulation pump for circulating a refrigerant in the heat exchanger, and a temperature of the reformed gas or the refrigerant discharged from the heat exchanger. Means, a third flow path for circulating the refrigerant discharged from the heat exchanger to the heat exchanger, a fifth flow path connecting the first three-way valve and the second three-way valve, and a second flow path. A third circulation pump installed, a sixth flow passage that communicates the second flow passage and the third flow passage, and a seventh flow passage that communicates the second flow passage. The fuel reformer according to claim 1, wherein the refrigerant at the outlet of the radiator is controlled to have a predetermined temperature while adjusting the flow rate of the refrigerant flowing in by the third circulation pump. 6. A first temperature difference detecting means for detecting a refrigerant temperature at an inlet / outlet port of the carbon monoxide remover, and a means for detecting a refrigerant temperature at an outlet of the first radiator. Second temperature difference detecting means for detecting a temperature difference between the refrigerant temperature at the first radiator outlet and the refrigerant temperature at the carbon monoxide remover outlet, the first temperature difference detecting means and the second temperature difference detecting means. And a circulation rate calculating means for calculating the mixing rate of the refrigerant supplied to the carbon monoxide remover based on the output of the means, and controlling the first three-way valve so that the mixing rate calculated by this circulation rate calculating means is obtained. The fuel reformer according to claim 1, wherein: 7. A fourth temperature difference detecting means for detecting a refrigerant temperature at an inlet / outlet of the heat exchanger and detecting a temperature difference between the heat exchanger and a means for detecting a refrigerant temperature at an outlet of the second radiator. The fifth temperature difference detecting means for detecting the temperature difference between the refrigerant temperature at the second radiator outlet and the refrigerant temperature at the heat exchanger outlet, and the outputs of the fourth temperature difference detecting means and the fifth temperature difference detecting means. And a second circulation rate calculation means for calculating the mixing rate of the refrigerant supplied to the heat exchanger, and controlling the second three-way valve so that the mixing rate calculated by the second circulation rate calculation means is obtained. The fuel reformer according to claim 2, wherein: 8. A first temperature difference detecting means for detecting a refrigerant temperature at an inlet / outlet port of the carbon monoxide remover, and a temperature difference detecting means, and a means for detecting a refrigerant temperature at an outlet of the first radiator. Second temperature difference detecting means for detecting a temperature difference between the refrigerant temperature at the first radiator outlet and the refrigerant temperature at the carbon monoxide remover outlet, the first temperature difference detecting means and the second temperature difference detecting means. Based on the output of the means, a circulation rate calculation means for calculating the mixing rate of the refrigerant supplied to the carbon monoxide remover, and a temperature difference between the temperature of the refrigerant at the outlet of the carbon monoxide remover and its target temperature. A third temperature difference detecting means, a PID control calculating means for calculating a correction rate of the mixing rate based on the temperature difference calculated by the third temperature difference detecting means, and a PID control for the mixing rate calculated by the circulation rate calculating means. The correction mixture calculated by the calculation means is added to calculate the correction mixture ratio. And an adding means for, first so that the calculated corrected mixing ratio in the adding means
The fuel reformer according to claim 1 or 2, wherein a three-way valve is controlled. 9. A fourth temperature difference detecting means for detecting a refrigerant temperature at the inlet / outlet of the heat exchanger and detecting a temperature difference between the heat exchanger, and a means for detecting a refrigerant temperature at an outlet of the second radiator. The fifth temperature difference detecting means for detecting the temperature difference between the refrigerant temperature at the second radiator outlet and the refrigerant temperature at the heat exchanger outlet, and the outputs of the fourth temperature difference detecting means and the fifth temperature difference detecting means. Based on the second circulation rate calculation means for calculating the mixing rate of the refrigerant supplied to the heat exchanger, and the sixth temperature difference detection for calculating the temperature difference between the temperature of the refrigerant at the outlet of the heat exchanger and its target temperature. Means, a second PID control calculating means for calculating a correction rate of the mixing rate based on the temperature difference calculated by the sixth temperature difference detecting means, and a second PID control calculating means for calculating the mixing rate calculated by the circulation rate calculating means. Second adding means for adding the corrected correction rates and calculating the corrected mixing rate Provided, fuel reforming apparatus according to claim 2 or 8, wherein the controller controls the second three-way valve so that the calculated corrected mixing ratio in the second addition means.