JPH07267603A - Reformer - Google Patents

Abstract

PURPOSE:To provide a reformer capable of efficiently carrying out the reduction of a reforming catalyst prior to the operation by selecting either of branch raw material gas feed lines and either of branch reformed gas discharge lines, reversing and changing over the gas flow direction in the reformer. CONSTITUTION:This reformer 16 is obtained by opening a raw material gas flow passage from a raw material gas feed line 50 to a branch raw material gas feed line (50a) with a three-way valve 19 for closing a valve 62 and opening a valve 64, opening valves 12 and 15, selecting the gas flow direction from the branch raw material gas feed line (50a) through the reformer 16 to a branch reformed gas discharge line (60b), feeding water and methanol to the reformer 16, discharging the produced gas discharged from the branch reformed gas discharge line (60b) to a reformed gas discharge line 60 to the outside air or feeding the produced gas to a burner in the reformer 16, changing over the flow passage from the raw material gas feed line 50 to the branch raw material feed line (50a) to the flow passage to the branch raw material gas feed line (50b), opening valves 13 and 14 and selecting the direction from the branch raw material gas feed line (50b) through the reformer 16 to the branch reformed gas discharge line (60a).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reformer, and more particularly to a reformer which performs a reduction operation of a reforming catalyst prior to reforming operation.

[0002]

2. Description of the Related Art A fuel cell using a power generation system based on an electrochemical reaction has high efficiency and excellent environmental characteristics.
Recently, it has been spotlighted as a small output battery. The principle of the fuel cell utilizes the reverse reaction of the electrolysis of water, that is, the electrical energy generated when hydrogen and oxygen combine to produce water. An actual fuel cell power generation system is mainly composed of a fuel cell main body for power generation, and is composed of a reformer for supplying hydrogen rich gas to the fuel cell main body and peripheral devices such as a humidifier for adding water to the rich gas. ing.

As a fuel hydrogen source used in this fuel cell, hydrogen obtained by steam reforming using natural gas as a raw material has been generally used.

However, when reforming such natural gas, the reforming reaction temperature is as high as 800 to 900 ° C., and additional equipment such as a desulfurizer and a CO shifter is required. Therefore, it is not suitable for a small output fuel cell power generation system used for a mobile power source or the like.

Therefore, the reforming reaction temperature is 200 to 300 ° C.
Methanol reformers, which are of a degree and do not require auxiliary equipment such as a desulfurization device, are receiving attention.

This methanol reformer decomposes the raw material methanol into a reformed gas rich in hydrogen gas by reacting methanol with a reforming catalyst in the presence of steam. This reaction is as shown in the following equation.

CH ₃ OH + H ₂ O → CO ₂ + 3H ₂ The reforming catalyst used at this time is, for example, a copper-zinc (Cu-Zn) type catalyst or a copper-zinc-chromium (Cu-Zn).
-Cr) -based catalyst, copper-zinc-aluminum (Cu-Zn
-Al) based catalysts, zinc-chromium (Zn-Cr) based catalysts and the like.

These reforming catalysts are filled in the reformer in an oxide state before use. Therefore, prior to the reforming operation in which the reformed gas rich in hydrogen gas is supplied to the fuel cell main body, the reforming catalyst must first be changed from the oxidized state to the activated state, that is, the reduced state.

As such a reduction treatment, for example, the "catalytic reduction method for a methanol reformer" in Japanese Patent Laid-Open No. 63-44933 has been proposed. JP-A-63-4493
Japanese Patent Publication No. 3 discloses a method in which raw material methanol and water are introduced into a reformer, and the reforming catalyst on the upstream side reduces the reforming catalyst on the downstream side by hydrogen gas generated by decomposition of methanol. Has been done.

Further, in the "methanol reforming apparatus" of Japanese Patent Laid-Open No. 63-44934, hydrogen gas is reformed from a separate system in order to reduce a reforming catalyst in an oxide state prior to reforming operation. There is described a device provided with a hydrogen gas supply source for supplying to.

However, in the case of the above method, means for separately storing hydrogen gas is required, and the system becomes large in size. Further, even if the reforming catalyst in the reformer is brought into a reducing state prior to the reforming operation, the fuel is When the reformed gas is supplied to the battery body for a long time, there is a problem that the reforming catalyst near the inlet of the reformer is gradually oxidized by a small amount of oxygen contained in the raw materials methanol and water.

When the reforming catalyst is oxidized, for example, in the case of a reforming catalyst containing copper, the following reaction occurs and the catalytic ability decreases.

2Cu + O ₂ → 2CuO Therefore, in the oxidized reforming catalyst near the inlet of the reformer,
Even if the raw material methanol is introduced, it is difficult to decompose and hydrogen gas is not easily generated.

Japanese Unexamined Patent Publication No. 3-103301 discloses a conventional plant reformer having a reforming reaction tube of several meters. In such a reformer having a long reforming reaction tube, even if the reforming catalyst near the inlet (for example, within several cm from the inlet) is oxidized, a sufficient amount of hydrogen gas is generated in other portions. Can be made.

[0015]

However, the size of the reaction tube of the reformer, which is required to be miniaturized such as mounted on an automobile, is inevitably about several tens of centimeters. For this reason,
When the reforming catalyst near the inlet is oxidized, the reforming reaction efficiency of the reformer is reduced and the hydrogen gas supply capacity to the fuel cell is reduced. This causes a problem that the output from the fuel cell also decreases.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide a reformer which efficiently reduces the reforming catalyst prior to the reforming operation.

[0017]

In order to achieve the above object, the reformer according to the present invention is a reformer for reforming a raw material gas by a catalytic reaction between the raw material gas and a reforming catalyst. A branch gas source gas supply line that is branched from a source gas supply line that supplies the source gas to the quality control unit and that is disposed at both ends of the reformer, and a reformer that is disposed at both ends of the reformer from the reformer. A branch line reformed gas outflow line that joins the reformed gas outflow line for outflowing gas, and
One of the branch line source gas supply line and the branch line reformed gas outflow line is selected according to the reduction state, and the gas flow direction in the reformer is reversed and switched.

In addition, in the reformer having the above-mentioned structure, reverse switching is performed each time the reformer is started.

Further, the reformer according to the present invention is a reformer for reforming a raw material gas by a catalytic reaction between the raw material gas and a reforming catalyst. A raw material gas supply line for supplying, a reformed gas outflow line which is disposed on the outlet side of the reformer and causes the reformed gas to flow out, and the reformed gas flowing out of the outlet of the reformer is recirculated to the inlet again. And a reformed gas recirculation line.

[0020]

According to the structure of the reformer, the branch source gas supply line branching from the source gas supply line for supplying the source gas to the reformer and disposed at both ends of the reformer, and the reformer Since it has a branch line reformed gas outflow line which is provided at both ends and joins a reformed gas outflow line for outflowing the reformed gas from the reformer, the flow path of the raw material gas can be reversed.
That is, the inlet for introducing the raw material gas of methanol and water and the outlet for flowing out the reformed gas containing the rich hydrogen gas obtained by decomposing methanol can be switched at a certain point. As a result, the reforming catalyst in a reduced state can be used as an inlet (upstream side) to rapidly decompose the introduced raw material methanol to generate hydrogen gas.
Then, by using the hydrogen gas generated on the upstream side, the reforming catalyst in the advanced oxidation state, which has become the outlet at the time of switching, can be reduced almost simultaneously with the switching.
Therefore, the reduction time of the reforming catalyst is shortened, and the reforming catalyst can be reduced with a small amount of methanol and water.

Further, by performing the above-mentioned inversion switching each time the reformer is started, the reduction process of the reforming catalyst can be performed when the reformer is started. As a result, the reformed gas rich in hydrogen gas can always be efficiently supplied to the fuel cell main body.

Further, since the reformed gas recirculation line for recirculating the reformed gas flowing out from the outlet of the reformer to the inlet again is provided, the reformed gas containing the rich hydrogen gas generated by decomposing the raw material methanol is reformed. By circulating the quality gas, the reforming catalyst in the oxidized state near the inlet can be reduced.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 is a block diagram showing the configuration of the first embodiment of the reformer according to the present invention. In addition, FIG. 3 shows the first shown in FIG.
It is a flow figure showing an outline of reduction processing operation of a reformer of an example.

As shown in FIG. 1, the reformer 16 of the present embodiment is filled with the above-mentioned reforming catalyst 17 and further has a vaporizing section 11 for mixing and vaporizing raw material methanol and water. And a raw material gas supply line 50 that supplies a mixed gas of methanol and water (hereinafter referred to as “raw material gas”) from the vaporization unit 11 to the reformer 16, and decomposes methanol from the reformer 16 to the fuel cell main body 18. A reformed gas outflow line 60 for outflowing the rich reformed gas of the generated hydrogen gas,
Have.

The feature of this embodiment is that branch line raw material gas supply lines 50a and 50b branched from the raw material gas supply line 50 and provided at both ends of the reformer 16 and the both ends of the reformer 16 are provided. And branch lines reformed gas outflow lines 60a and 60b that join the reformed gas outflow line 60. As a result, the branch source gas supply line 50a,
50b is switched, and an inlet for introducing a raw material gas of methanol and water and an outlet for flowing out a rich reformed gas of hydrogen gas obtained by decomposing methanol are inverted and switched depending on the oxidation / reduction state of the reforming catalyst. However, the gas flow direction in the reformer 16 can be changed. Therefore, the reforming catalyst 17 in a reduced state, that is, in an active state is switched to the inlet side (upstream side), the supplied raw material methanol is rapidly decomposed to generate hydrogen gas, and the hydrogen gas is generated upstream of this. The hydrogen gas can be used to quickly reduce the reforming catalyst 17 on the outlet side after switching.

A three-way valve 19 for controlling the flow path of the raw material gas is provided at a branch point between the branch raw material gas supply line 50a and the branch raw material gas supply line 50b, and the branch raw material gas supply line 50a. , 50b and branch line reformed gas outflow lines 60a, 60b are provided with valves 12, 1 respectively.
3, 14, 15 are provided. Further, a valve 62 is provided in the reformed gas outflow line 60, and a line branched from the reformed gas outflow line 60 to supply the reaction gas generated after reducing the reforming catalyst to the outside air or the burner of the reformer. A valve 64 is provided in the. In this embodiment, the valves 12, 13, 14, 15, 62, 6 are
Reference numeral 4 denotes a solenoid valve, which is latched and driven by an electric signal from a control unit (not shown).

Next, an outline of the reduction treatment operation of the reformer of this embodiment will be described with reference to FIGS. 1 and 3. The operation of the reduction process of the reformer filled with the reforming catalyst in the oxidized state will be described below.

Before the reforming process, the valves 12, 13, 14,
15 is in the "closed" state.

First, the valve 62 is closed and the valve 64 is opened. Then, the three-way valve 19 opens the source gas flow path from the source gas supply line 50 to the branch line source gas supply line 50a (S31). Next, the valves 12 and 15 are opened (S32), and the branch line source gas supply line 50a.
From the branch line through the reformer 16 to the reformed gas outflow line 60b
Select the gas flow direction to. Then, 50 cc of water and 50 cc of methanol are supplied to the reformer 16 over 5 minutes (S33). At that time, the produced gas flowing out from the branch line reformed gas outflow line 60b to the reformed gas outflow line 60 is discharged to the outside air through a predetermined processing line or supplied to the burner of the reformer to heat the reforming catalyst. Is used as a heat source. As a result, the portion c of the reforming catalyst 17 is in a state where reduction has progressed, while the portion a is an inlet portion, so the hydrogen concentration is low and the reduction reaction is not sufficiently performed. In addition,
The reformer of this embodiment has a capacity of about 5 to 10 liters.

Then, next, in order to switch the gas flow direction in the reformer 16 in the reverse direction, first, by the three-way valve 19, from the source gas supply line 50 to the branch source gas supply line 50.
The raw material gas flow path to a is switched to the raw material gas flow path from the raw material gas supply line 50 to the branch raw material gas supply line 50b (S34). Next, the valves 13 and 14 are opened (S35), and the gas flow direction from the branch raw material gas supply line 50b to the branch reformed gas outflow line 60a via the reformer 16 is selected. Then, the raw material gas that is equal to or smaller than the predetermined amount in the previous step is supplied to the reformer 16 for a predetermined time (<5 minutes) (S36). Then, after a predetermined amount of raw material gas is supplied for a predetermined time, the reduction process is completed (S
37). After the reduction process, the valve 64 is closed and the valve 62 is opened, and the hydrogen gas-rich reformed gas generated by the reformer 16 is supplied to the fuel cell body 18.
The timing of switching and the amount and time of the source gas to be supplied may be controlled according to the amount of hydrogen produced.

Further, the operation of the reduction treatment each time the reformer is started up may be performed by switching the gas passage before the stop by switching the three-way valve 19 and supplying the raw material gas. As a result, the pleasant gas can be generated while reducing the stop-time inlet portion oxidized by oxygen contained in the raw material gas during use. For example, in the operation before the stop, the raw material gas supply line 50 and the branch line raw material gas supply line 50a circulate, and the reforming catalyst 1
When the portion a of 7 is the inlet of the reformer 16 and the portion c of the reforming catalyst is the outlet of the reformer 16, the portion a of the reforming catalyst 17 is exposed to oxygen contained in the raw material gas. Therefore, the degree of oxidation is higher than that of the portion c.

Therefore, the valve 62 is closed and the valve 64 is opened. Then, in order to switch the gas flow direction in the reformer 16 in the reverse direction, first, the three-way valve 19 is used to set the raw material gas flow path from the raw material gas supply line 50 to the branch raw material gas supply line 50a. To the raw material gas flow path from the branch line to the raw material gas supply line 50b. Next, the valves 13 and 14 are opened, and the gas flow direction from the branch raw material gas supply line 50b to the branch reformed gas outflow line 60a via the reformer 16 is selected. Then, the hydrogen gas-rich reformed gas generated by the reformer 16 while reducing the inlet with the raw material gas is supplied to the fuel cell main body 18.

By the above reforming operation, the portion c of the reforming catalyst 17 in the reduced state serves as an inlet, and the supplied methanol can be rapidly decomposed to generate hydrogen gas. The generated hydrogen gas As a result, it is possible to reduce the portion a of the reforming catalyst 17 in the advanced oxidation state which has become the outlet at the time of switching. Therefore, the reduction treatment time is further shortened, and the reforming catalyst can be reduced with a small amount of methanol and water.

Here, the gas flow path is switched every time the engine is started, but when operating for a long time, the gas flow path may be switched every predetermined time.

The time for the reduction treatment and the amount of the raw material gas supplied are appropriately determined depending on the volume of the reformer, the type of the reforming catalyst and the oxidation state of the reforming catalyst.

When stopped, the valves 12, 13, 14,
Even if 15 is closed, air may flow into the reformer 16 for some reason (for example, in the case of a vehicle, a leak or the like). In this case, both ends of the reforming catalyst are similarly oxidized. However, if the oxidation due to oxygen contained in the raw material gas during reforming is taken into consideration, the degree of oxidation at the end that was the inlet side last time is still large. Therefore, even when the oxidation during stoppage is taken into consideration, the reforming catalyst can be uniformly reduced only by switching the portion on the inlet side to the outlet side.

Second Embodiment FIG. 2 is a block diagram showing the configuration of the second embodiment of the reformer according to the present invention. In addition, FIG. 4 is the second shown in FIG.
It is a flow figure showing an outline of reduction processing operation of a reformer of an example. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 2, the reformer 16 of this embodiment is provided with a raw material gas which is provided between the vaporizing section 11 and the inlet of the reformer 16 to supply the raw material gas to the reformer 16. Line 7
0 and a reformed gas outflow line 80 that is piped between the fuel cell main body 18 and the outlet side of the reformer 16 to let out the reformed gas.
And the reformer 1 branched from the reformed gas outflow line 80.
And a reformed gas recirculation line 90 for recirculating the reformed gas flowing out from the outlet 6 to the inlet again. Further, the reformed gas outflow line 80 and the reformed gas recirculation line 90 are provided with valves 68 and 66 for controlling the flow paths of the reformed gas, respectively.
Further, the reformed gas recirculation line 90 is provided with a recirculation pump 25. Further, the raw material gas supply line 70, the reformed gas outflow line 80, and the reformed gas recirculation line 90 are provided with valves 22, 23, 24, respectively. In the embodiment, these valves 22, 23, 2 are provided.
Reference numerals 4, 66, 68 are solenoid valves, which are latched and driven by electric signals from a control unit (not shown).

The feature of this embodiment is that a reformed gas recirculation line 90 for recirculating the reformed gas flowing out from the outlet of the reformer 16 to the inlet again is provided. As a result, the hydrogen-rich reformed gas flowing out from the outlet can be circulated to reduce the oxidized reforming catalyst near the inlet.

Next, an outline of the reduction treatment operation of the reformer of this embodiment will be described with reference to FIGS. 2 and 4. The operation of the reduction process of the reformer filled with the reforming catalyst in an oxidized state will be described below. First, the valve 66 is opened and the valve 68 is closed, and the reformed gas flow path from the reformed gas outflow line 80 to the fuel cell body 18 and the reformed gas from the reformed gas outflow line 80 to the reformed gas recirculation line 90. Switching to the flow path (S40). Next, the valves 22, 23, 24 are “opened” (S41), and the raw material gas is caused to flow into the raw material gas supply line 70 from the vaporization section 11. Next, the pump 25 is driven (S42), a predetermined amount of the raw material gas is supplied to the reformer 16 for a predetermined time (S43), and the hydrogen gas-rich reforming obtained by the reforming reaction in the reformer 16 is performed. Gas reformer 1
Circulate from outlet 6 to inlet 6. When the internal pressure of the reformer 16 becomes equal to or higher than a predetermined value, or after a predetermined amount of the raw material gas is supplied for a predetermined time, the valve 22 is “closed”, the supply of the raw material gas is stopped, and the pump 25 is operated. The hydrogen gas-rich reformed gas flowing out from the outlet is fed to the reformed gas recirculation line 9
0 is circulated for a predetermined time or a predetermined amount to reduce the reforming catalyst 17 in the reformer 16. Then, the pump 25 is stopped (S44), and the valve 24 is closed (S4).
5). Next, the valve 66 is closed, the valve 68 is opened, and the valve 22 is further opened to return to the reformed gas flow path from the reformed gas outflow line 80 to the fuel cell main body 18 (S4).
6) The reduction process is completed (S47). Then, the hydrogen gas generated by the reformer 16 is supplied to the fuel cell main body 18. During the reflux, a small amount of the reformed reformed gas is leaked, and the internal pressure in the line is controlled so as not to rise. Further, the time of the reduction treatment and the supply amount of the raw material gas are appropriately determined depending on the volume of the reformer, the type of the reforming catalyst and the oxidation state of the reforming catalyst.

The operation of the reduction process when the reformer is restarted will be described with reference to FIG. The valves 22, 23 and 24 are in the “closed” state before the reduction process is stopped, and the reformed gas outflow line 80 is in the open state during the operation before the stop.

First, the valve 66 is opened by a predetermined amount and the valve 68 is also opened. That is, the reducing hydrogen gas is supplied to the reformed gas outflow line 80, and the reformed gas is also supplied to the fuel cell main body 18 via the reformed gas recirculation line 90. That is, the valves 22, 23, 24 are “opened”, and the raw material gas is supplied from the vaporization section 11 to the raw material gas supply line 70.
Flow into. Next, the pump 25 is driven to supply a predetermined amount of the raw material gas to the reformer 16 for a predetermined time.
The hydrogen gas-rich reformed gas obtained by the reforming reaction inside is circulated from the outlet of the reformer 16 to the inlet. After supplying a predetermined amount of raw material gas for a predetermined time, the pump 25 is stopped and the valve 24 is closed. Next, the valve 68 is closed and the reduction process is completed. Then, the reformed gas from the reformer 16 is supplied to the fuel cell main body 18 via the reformed gas recirculation line 90. During the reflux, a small amount of the reformed reformed gas is leaked, and the internal pressure in the line is controlled so as not to rise. Further, the time of the reduction treatment and the supply amount of the raw material gas are appropriately determined depending on the volume of the reformer, the type of the reforming catalyst and the oxidation state of the reforming catalyst.

Although the flow path is switched after the start-up as described above, the flow path may be switched every predetermined time when operating for a long time.

By the above reduction operation, the high-concentration hydrogen gas in the reformed gas flowing out from the portion c of the reforming catalyst 17 in the reduced state shown in FIG.
Of the reforming catalyst in the oxidized state can be restored to the reduced state.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to this, and the valve is not limited to the solenoid valve, and may be a manual valve.

[0047]

As described above, according to the reformer according to the present invention, the branch line raw material branched from the raw material gas supply line for supplying the raw material gas to the reformer and arranged at both ends of the reformer. Since it has a gas supply line and a branch line reformed gas outflow line which is provided at both ends of the reformer and joins with the reformed gas outflow line for outflowing the reformed gas from the reformer, an inlet for introducing the raw material gas and The outlet for letting out the hydrogen-rich reformed gas can be switched at a certain point. As a result, the reforming catalyst in a state of advanced reduction is used as an inlet, and the introduced raw material gas is rapidly decomposed to generate hydrogen gas,
The generated hydrogen gas can be used to reduce the reforming catalyst on the outlet side (that is, the inlet before switching) in an insufficiently reduced state. Therefore, the reduction treatment time is shortened, and the reforming catalyst can be reduced with a small amount of raw material gas.

Further, by performing the above-mentioned inversion switching each time the reformer is started, the reduction process of the reforming catalyst can be performed when the reformer is started. As a result, the reformed gas rich in hydrogen gas can always be stably supplied to the fuel cell main body.

Further, by providing the reformed gas recirculation line for recirculating the reformed gas flowing out from the outlet of the reformer to the inlet again, the hydrogen-rich gas is circulated and the reforming catalyst in the oxidized state near the inlet is circulated. It can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a first embodiment of a reformer according to the present invention.

FIG. 2 is a block diagram showing the configuration of a second embodiment of the reformer according to the present invention.

FIG. 3 is a flowchart showing an outline of a reduction treatment operation of the reformer of the first embodiment shown in FIG.

FIG. 4 is a flowchart showing an outline of a reduction treatment operation of the reformer of the second embodiment shown in FIG.

[Explanation of symbols]

 11 Vaporizing part 12, 13, 14, 15 Valve 16 Reformer 17 Reforming catalyst 18 Fuel cell body 19 3-way valve 22, 23, 24, 62, 64 Valve 25 Pump 29 3-way valve 50, 70 Raw gas supply line 60, 80 reformed gas outflow line 50a, 50b branch line raw material gas supply line 60a, 60b branch line reformed gas outflow line 90 reformed gas recirculation line

Claims (3)

[Claims] 1. A reformer for reforming a raw material gas by a contact reaction between the raw material gas and a reforming catalyst, wherein the reformer is branched from a raw material gas supply line for supplying the raw material gas to both ends of the reformer. And a branch line reformed gas outflow line which is provided at both ends of the reformer and which joins to a reformed gas outflow line for outflowing the reformed gas from the reformer. According to the oxidation / reduction state of the reforming catalyst, one of the branch raw material gas supply line and one of the branch reformed gas outflow line is selected to reverse the gas flow direction in the reformer. Reformer characterized by. 2. The reformer according to claim 1, wherein reverse switching is performed each time the reformer is started. 3. A reformer for reforming a raw material gas by a contact reaction between the raw material gas and a reforming catalyst; a raw material gas supply line disposed on the inlet side of the reformer for supplying the raw material gas; A reformed gas outflow line disposed on the outlet side of the reformer for flowing out reformed gas; and a reformed gas recirculation line for recirculating the reformed gas flowing out of the reformer outlet to the inlet again. A reformer characterized by that.