JP2012201575A - Co removing device and fuel reforming system provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve good response to the change of a heat generation region due to local heat generation and the change of power generation load, and to improve reliability of control.SOLUTION: A thermal control tube 4 in which a heat medium causing a gas-liquid phase change is encapsulated is disposed in such a way that it vertically penetrates a reaction vessel 1. An electric heater 5 is disposed at the bottom of the thermal control tube 4, and a heat radiator 6 and a cooling fan 7 for sending cold air to the heat radiator 6 are disposed on the top of the thermal control tube 4. A first temperature sensor 8 is provided to the lower part of the thermal control tube 4, a second temperature sensor 9 to an upper part, and a controller 10 is connected to the first and second temperature sensors 8, 9. The controller 10 is also connected to the electric heater 5 and the cooling fan 7, and on the basis of the temperatures of the heat medium measured with the first and second temperature sensors 8, 9, the electric heater 5 and the cooling fan 7 are operated to maintain the temperature of the catalyst within a preset range.

Description

  The present invention relates to a CO removal device for reducing CO concentration by reacting CO in a reformed gas mainly composed of hydrogen obtained by reforming raw fuel with a catalyst filled in a reaction vessel, and The present invention relates to a fuel reforming system including

In the CO removal device, it is necessary to raise the temperature to a certain level with a catalyst during the methanation reaction of CO. However, if the temperature is raised too much, the methanation reaction is exothermic and the reaction rate increases. There is a risk of thermal runaway, and it has been necessary to strictly control the temperature of the catalyst layer so as to keep it below the temperature at which thermal runaway does not occur.
Therefore, conventionally, a cooling fluid flow passage portion for passing a cooling fluid such as combustion air is provided adjacent to the reaction vessel filled with the catalyst to cool the reaction vessel, and the combustion air is provided there. It is configured to flow and cool. (Patent Document 1)

Japanese Patent No. 4063430

  However, in the catalyst layer, the reaction zone, that is, the heat generation zone changes due to the change in the power generation load. In order to cope with such a change in the heat generation region, a large number of combustion air passages are branched so that the desired portion can be cooled with respect to the catalyst layer, and the combustion air is supplied to the heated portion in a concentrated manner. As a result, the control configuration becomes complicated, and it is difficult to supply the combustion air quickly, resulting in a decrease in reliability.

  The present invention has been made in view of such circumstances, and the invention according to claim 1 can satisfactorily cope with changes in the heat generation area due to local heat generation or changes in the power generation load, and is reliable in control. The purpose is to improve the performance.

In order to achieve the above-described object, the invention according to claim 1
In a CO removal apparatus for reducing CO concentration by reacting CO in a reformed gas mainly composed of hydrogen obtained by reforming raw fuel with a catalyst filled in a reaction vessel,
A heat control pipe provided to enclose a heat medium that changes phase in the pipe and to transmit heat of the heat medium to the catalyst in the reaction vessel;
Heating means for heating the heat medium in the heat control pipe to vaporize the heat medium;
Cooling means for cooling the heat medium in the heat control tube to liquefy the gaseous heat medium;
A catalyst temperature measuring means for measuring the temperature of the catalyst;
Catalyst temperature control means for controlling the operation of the heating means or the cooling means so that the temperature of the catalyst is maintained within a set range based on the temperature of the catalyst measured by the catalyst temperature measuring means;
It is characterized by having.

(Action / Effect)
According to the configuration of the CO removal apparatus of the invention according to claim 1, when the temperature of the catalyst is low at the start-up, the heat medium is heated and vaporized by the heating means, and the heat medium is condensed and condensed by heat transfer to the catalyst. Latent heat can be applied to increase the temperature of the catalyst and maintain the catalyst at a temperature within a set range. On the other hand, when the reaction proceeds and the temperature of the catalyst exceeds the set range and generates heat, the cooling medium liquefies the gaseous heat medium in the heat control tube, evaporates the heat medium close to the heat generation area of the reaction vessel, and vaporizes latent heat. Can cool the catalyst in the heat generating region and maintain the catalyst at a temperature within the set range.
Therefore, even if the heat is generated locally or the heat generation area changes due to a change in the power generation load, the heat medium near the heat generation area evaporates, and the catalyst in the heat generation area is cooled by the latent heat of vaporization. The heat medium moves freely in the control pipe, and the required amount of heat medium naturally gathers in the heat generation area, which can respond well to local heat generation and changes in the heat generation area due to changes in power generation load, and thermal runaway Can be avoided.
In addition, since the temperature of the catalyst in the reaction vessel is controlled depending on whether the heat medium in the heat control tube is vaporized or liquefied, a heating unit is provided in the lower part of the heat control tube and a cooling unit is provided in the upper part. It is only necessary to control the heating means and the cooling means, and it is not necessary to provide a heat transfer member over the entire reaction vessel, and the configuration can be simplified and the control reliability can be improved.

The invention according to claim 2
The heating means uses at least one of an electric heater, a heat exchange means by combustion exhaust gas, and a thermoelectric conversion element that generates heat by energization,
The cooling means is a cooling water heat exchange means using fuel cell cooling water, a secondary cooling water heat exchange means using fuel cell cooling secondary cooling water, and a reforming raw fuel heat exchange using reforming raw fuel supplied to the reformer. Used in reforming water heat exchange means using water for steam reforming, combustion air heat exchange means using air for burning unreacted fuel discharged from the fuel cell, and reformer combining partial combustion and steam reforming The at least one of the catalytic combustion air heat exchange means by the catalytic combustion air and the ambient air heat exchange means by heat radiation to the ambient air of the reformer is used. This is a CO removal apparatus.

(Action / Effect)
According to the configuration of the CO removal apparatus of the invention according to claim 2, since the heating means and the cooling means may be provided at the lower part and the upper part of the heat control pipe, depending on the situation such as the installation place and application of the CO removal apparatus. As each of the heating means and the cooling means, a suitable one can be selected and used from the above-mentioned plural types, and the apparatus can be constructed at low cost, which is economical.

The invention according to claim 3
The heat medium is selected from at least one of water, an electrolyte solution, and a heat transfer oil that changes phase from a liquid phase to a gas phase when reaching a temperature range in which a CO removal reaction proceeds. It is a CO removal apparatus of Claim 1 or 2.

(Action / Effect)
According to the configuration of the CO removal apparatus of the invention according to claim 3, the heat medium that is easily available as described above and that can easily cope with the temperature range where the CO removal reaction proceeds by adjusting the pressure is selected. It is economical because the apparatus can be constructed at low cost.

The invention according to claim 4
4. The CO removing apparatus according to claim 1, wherein the heat control pipe is divided into a heating dedicated heat control pipe and a cooling dedicated heat control pipe. 5.

(Action / Effect)
According to the configuration of the CO removing device of the invention according to claim 4, the heat medium sealing pressure is individually adjusted between the heating-only heat control pipe and the cooling-only heat control pipe. The thing of a structure can be used and the reliability of control can be improved further although it is a simple structure.

The invention according to claim 5
A heat exchanger and a drain discharger are installed in the reformed gas supply pipe for supplying the reformed gas to the reaction vessel, and the dew point of water in the reformed gas supplied to the reaction vessel is adjusted to 30 to 60 ° C. The CO removing device according to any one of claims 1 to 4, wherein the device is a CO removing device.
If the dew point of water in the reformed gas is less than 30 ° C, a large cooling facility is required and expensive. On the other hand, if the dew point of water exceeds 60 ° C, the amount of water vapor increases and the equilibrium reaction becomes disadvantageous. This is because the CO removal rate decreases.

(Action / Effect)
According to the configuration of the CO removing apparatus of the invention according to claim 5, the coexisting water vapor in the reformed gas supplied to the reaction vessel is removed by the drain discharger, and the CO methanation reaction (CO + 3H ₂ = CH ₄ + H ₂ O). ) Can be suppressed.
Therefore, CO removal can be promoted, and the cooling facility can be saved without increasing the size, and it is economical and the CO removal rate can be improved.

The invention according to claim 6
6. A fuel comprising the CO removing device according to any one of claims 1 to 5 and a CO converter for converting CO in the reformed fuel gas into hydrogen in a flat plate stack type. It is a reforming system.

(Action / Effect)
According to the configuration of the fuel reforming system of the invention according to claim 6, since the CO removing device and the CO transformer are configured in a flat plate stack type, the fuel reforming system can be configured in a compact manner.

The invention according to claim 7 provides:
A fuel reforming system comprising the CO removing device according to any one of claims 1 to 5.

(Action / Effect)
According to the configuration of the fuel reforming system of the invention according to claim 7, the CO removal rate in the CO removing device can be improved and the CO concentration in the reformed gas can be reduced. For example, if a solid polymer fuel cell is configured with this fuel reforming system, the power generation efficiency can be improved.

As is clear from the above description, according to the configuration of the CO removal apparatus of the invention according to claim 1, when the temperature of the catalyst is low at the time of startup, the heating medium is heated and vaporized by the heating means, and transmitted to the catalyst. The heat medium is condensed by heat and gives latent heat of condensation to increase the temperature of the catalyst, and the catalyst can be maintained at a temperature within a set range. On the other hand, when the reaction proceeds and the temperature of the catalyst exceeds the set range and generates heat, the cooling medium liquefies the gaseous heat medium in the heat control tube, evaporates the heat medium close to the heat generation area of the reaction vessel, and vaporizes latent heat. Can cool the catalyst in the heat generating region and maintain the catalyst at a temperature within the set range.
Therefore, even if the heat is generated locally or the heat generation area changes due to a change in the power generation load, the heat medium near the heat generation area evaporates, and the catalyst in the heat generation area is cooled by the latent heat of vaporization. The heat medium moves freely in the control pipe, and the required amount of heat medium naturally gathers in the heat generation area, which can respond well to local heat generation and changes in the heat generation area due to changes in power generation load, and thermal runaway Can be avoided.
In addition, since the temperature of the catalyst in the reaction vessel is controlled depending on whether the heat medium in the heat control tube is vaporized or liquefied, a heating unit is provided in the lower part of the heat control tube and a cooling unit is provided in the upper part. It is only necessary to control the heating means and the cooling means, and it is not necessary to provide a heat transfer member over the entire reaction vessel, and the configuration can be simplified and the control reliability can be improved.

1 is an overall schematic cross-sectional view showing a schematic configuration of a CO removing apparatus according to Embodiment 1 of the present invention. It is a whole schematic sectional drawing which shows schematic structure of the CO removal apparatus of Example 2 which concerns on this invention. It is a whole schematic sectional drawing which shows schematic structure of the CO removal apparatus of Example 3 which concerns on this invention. It is sectional drawing of the fuel reforming system of Example 4 which concerns on this invention.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an overall schematic cross-sectional view showing a schematic configuration of a CO removing apparatus according to a first embodiment of the present invention, in which raw fuels such as hydrocarbons and methanol are reformed in a lower part of a reaction vessel 1 filled with a catalyst. A reformed gas supply pipe 2 for supplying a reformed gas containing hydrogen as a main component is provided. On the other hand, a CO removal gas extraction pipe 3 for taking out the CO removal gas is provided at the upper part of the reaction vessel 1. A CO removal device is configured to reduce CO concentration by methanation by reacting CO in a gas with hydrogen using a catalyst.

  A heat control pipe 4 penetrating the reaction vessel 1 up and down and enclosing a heat medium that changes in a gas-liquid phase is provided, and configured to transmit heat of the heat medium to a catalyst in the reaction vessel. An electric heater 5 is attached to the lower part of the heat control tube 4 as a heating means for heating the heat medium and vaporizing the heat medium at the time of activation. A heat radiator 6 and a cooling fan 7 that sends cold air to the heat radiator 6 are provided on the upper portion of the heat control pipe 4. The radiator 6 and the cooling fan 7 constitute cooling means for cooling the heat medium and liquefying the gaseous heat medium.

A first temperature sensor 8 is provided at a predetermined height above the lower end on the lower side of the heat control pipe 4, while a second temperature sensor 9 is provided at a position below the predetermined height from the upper end on the upper side of the heat control pipe 4. And a catalyst temperature measuring means for measuring the temperature of the catalyst in the reaction vessel 1 substantially by measuring the temperature of the heat medium in the heat control pipe 4 is configured.
A controller 10 as catalyst temperature control means is connected to the first and second temperature sensors 8 and 9, and the controller 10, the electric heater 5, and the cooling fan 7 are connected.

  With the above configuration, when the temperature measured by the first temperature sensor 8 is the liquid phase temperature state of the heating medium, the heating medium is heated by operating the electric heater 5 to increase the temperature of the catalyst in the reaction vessel 1. On the other hand, when the temperature measured by the second temperature sensor 9 is the gas phase temperature state of the heat medium, the heat medium is cooled by starting the cooling fan 7 to be used as the catalyst in the reaction vessel 1. Heat is transferred to lower the temperature, and the temperature of the catalyst is maintained within a set range.

FIG. 2 is an overall schematic cross-sectional view showing a schematic configuration of the CO removing apparatus according to the second embodiment of the present invention. The differences from the first embodiment are as follows.
That is, the heat control pipe 21 is installed in a shared manner between the heating-only heat control pipe 22 and the cooling-only heat control pipe 23. Other configurations are the same as those of the first embodiment, and the same reference numerals are given and description thereof is omitted.

  According to the second embodiment, it is possible to change the pressure of the heat medium sealed in each of the heating-only heat control pipe 22 and the cooling-only heat control pipe 23. The reliability of control can be further improved while being usable and having a simple configuration.

FIG. 3 is an overall schematic cross-sectional view showing a schematic configuration of the CO removing apparatus according to the third embodiment of the present invention. The differences from the first embodiment are as follows.
That is, a reformer gas supplied to the reaction vessel 1 is provided with a condenser 31 and a drain discharger 32 as heat exchangers in the reformed gas supply pipe 2 that supplies the reformed gas to the reaction vessel 1. It is comprised so that the dew point of the inside water may be adjusted to 30-60 degreeC. Other configurations are the same as those of the first embodiment, and the same reference numerals are given and description thereof is omitted.

According to the third embodiment, the coexisting water vapor in the reformed gas supplied to the reaction vessel 1 is removed by the drain discharger 32, and the reverse of the CO methanation reaction (CO + 3H ₂ = CH ₄ + H ₂ O) is suppressed. Can do.
Moreover, since the dew point of water is adjusted to 30 ° C. to 60 ° C., it is not necessary to increase the size of the cooling facility, which is economical and the CO removal rate can be improved.

FIG. 4 is a cross-sectional view of a fuel reforming system according to a fourth embodiment of the present invention, in which a CO removing device and a CO transformer are configured in a flat plate stack type, which will be described in detail below.
That is, the water vapor generating part 41 composed of a double space equipped container, the combustion exhaust gas flow part 42 for heating it, the first heat insulating material 43, the combustion reaction part 44 composed of a double space equipped container, and a reforming reactor 45, the temperature-reforming reformed gas flow portion 46 constituted by a single space-equipped container, a second heat insulating material 47, a to-be-reformed gas flow portion 48 constituted by a double-spaced equipped vessel, and an upstream side reformed gas flow The flow part 49, the third heat insulating material 50, the desulfurizer 51 and raw fuel flow part 52 composed of a twin space equipped container, the downstream reformed gas flow part 53 composed of a double space equipped container and the first The CO converter 54, the second CO converter 55 composed of a double space equipped container, the combustion exhaust gas flow part 56 for flowing low-temperature combustion exhaust gas through the combustion exhaust gas flow part 42, and the double space equipped container The third CO transformer 57 and the fourth CO transformer 58, the fourth heat insulating material 59, Beauty, CO selective oxidizer 60 as a reaction vessel using a half of the bi-space equipped container is stacked fuel reformer system is configured. In the figure, 61 is

  The CO selective oxidizer 60 is vertically penetrated and several heat control pipes 4 are arranged in the depth direction in the drawing, the electric heater 5 is provided below the heat control pipe 4, and the radiator 6 is provided above. Each is attached.

The heating means for heating the heat medium at the lower part of the heat control pipe 4 is not limited to the electric heater 5 as in the above-described embodiment. For example, a heat exchange means using combustion exhaust gas, or a thermoelectric conversion element that generates heat when energized. Etc. are applicable.
Further, the cooling means for cooling the heat medium at the lower part of the heat control pipe 4 is not limited to the cooling configuration by the radiator 6 as in the above-described embodiment, but the cooling water heat exchange means by the fuel cell cooling water, for cooling the fuel cell Secondary cooling water heat exchanging means by secondary cooling water, reforming raw fuel heat exchanging means by reforming raw fuel supplied to reformer, reforming water heat exchanging means by water for steam reforming, discharged from fuel cell Combustion air heat exchange means by air supplied to burn the unreacted fuel to be burned, catalytic combustion air heat exchange by catalytic combustion air supplied for use in a reformer that combines partial combustion and steam reforming Means, ambient air heat exchange means by heat radiation to the ambient air of the reformer can be applied.

  The heat medium sealed in the heat control tube 4 may be any heat medium that changes from the liquid phase to the gas phase when reaching the temperature range where the CO removal reaction proceeds. Water, electrolyte solution, heat transfer oil (alternative chlorofluorocarbon) ) Etc. are applicable.

  In the fourth embodiment, the flat plate stack type fuel reforming system provided with the CO selective oxidizer 60 is shown. However, as the CO removing apparatus of the present invention, the CO concentration is determined by either the methanation reaction or the selective oxidation reaction. In addition, any fuel reforming system may be used as long as it has any type of CO removing device.

DESCRIPTION OF SYMBOLS 1 ... Reaction container 2 ... Reformed gas supply pipe 4 ... Thermal control pipe 5 ... Electric heater (heating means)
6 ... Radiator (cooling means)
7. Cooling fan (cooling means)
8: First temperature sensor (catalyst temperature measuring means)
9: Second temperature sensor (catalyst temperature measuring means)
10 ... Controller (Catalyst temperature control means)
DESCRIPTION OF SYMBOLS 21 ... Thermal control pipe 22 ... Heating exclusive control pipe 23 ... Cooling exclusive thermal control pipe 54 ... 1st CO converter 55 ... 2nd CO converter 57 ... 3rd CO converter 58 ... 4th CO conversion 60 ... CO selective oxidizer (reaction vessel)

Claims (7)

In a CO removal apparatus for reducing CO concentration by reacting CO in a reformed gas mainly composed of hydrogen obtained by reforming raw fuel with a catalyst filled in a reaction vessel,
A heat control pipe provided to enclose a heat medium that changes phase in the pipe and to transmit heat of the heat medium to the catalyst in the reaction vessel;
Heating means for heating the heat medium in the heat control pipe to vaporize the heat medium;
Cooling means for cooling the heat medium in the heat control tube to liquefy the gaseous heat medium;
A catalyst temperature measuring means for measuring the temperature of the catalyst;
Catalyst temperature control means for controlling the operation of the heating means or the cooling means so that the temperature of the catalyst is maintained within a set range based on the temperature of the catalyst measured by the catalyst temperature measuring means;
A CO removal apparatus comprising: The heating means uses at least one of an electric heater, a heat exchange means by combustion exhaust gas, and a thermoelectric conversion element that generates heat by energization,
The cooling means is a cooling water heat exchange means using fuel cell cooling water, a secondary cooling water heat exchange means using fuel cell cooling secondary cooling water, and a reforming raw fuel heat exchange using reforming raw fuel supplied to the reformer. Used in reforming water heat exchange means using water for steam reforming, combustion air heat exchange means using air for burning unreacted fuel discharged from the fuel cell, and reformer combining partial combustion and steam reforming The at least one of the catalytic combustion air heat exchange means by the catalytic combustion air and the ambient air heat exchange means by heat radiation to the ambient air of the reformer is used. CO removal device. The heat medium is selected from at least one of water, an electrolyte solution, and a heat transfer oil that changes phase from a liquid phase to a gas phase when reaching a temperature range in which a CO removal reaction proceeds. The CO removal apparatus according to claim 1 or 2. The CO removal apparatus according to any one of claims 1 to 3, wherein the heat control pipe is divided into a heat dedicated heat control pipe and a cooling dedicated heat control pipe. A heat exchanger and a drain discharger are installed in the reformed gas supply pipe for supplying the reformed gas to the reaction vessel, and the dew point of water in the reformed gas supplied to the reaction vessel is adjusted to 30 to 60 ° C. The CO removal apparatus according to any one of claims 1 to 4, wherein 6. A fuel comprising the CO removing device according to any one of claims 1 to 5 and a CO converter for converting CO in the reformed fuel gas into hydrogen in a flat plate stack type. Reforming system. A fuel reforming system comprising the CO removing device according to any one of claims 1 to 5.

Images