JPH0372563B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a re-former, and in particular to a re-former that combines a re-former and a heat exchanger, which is suitable for downsizing and increasing efficiency of commercial fuel cell systems, etc. It is related to.

[Background of the invention]

A fuel cell system for commercial use must be small and have low heat loss, and the integration of its constituent elements, the rifoma, peripheral equipment, and heat exchanger, is being considered.

First, a conventional re-former will be explained with reference to FIG.

FIG. 1 is a longitudinal sectional view of a conventional re-former and a system diagram showing peripheral equipment and gas flows. In the figure, solid arrows indicate natural gas, dashed arrows indicate water vapor,
The two-dot chain arrow indicates the flow of combustion gas or combustion exhaust gas, and the thick solid arrow indicates the flow of reformed gas.

Reference numeral 1 denotes a reformer, 2 an outer tube of the reaction tube, and 3 an inner tube of the reaction tube. The annular portion formed by the outer tube 2 and the inner tube 3 is collectively referred to as the reaction tube. In the reaction tube, a mixed gas of natural gas and steam is heated, and a steam reforming reaction is caused by the action of the catalyst 4. Reference numeral 5 denotes a body that houses these reaction tubes, and is lined with a heat insulating material 6 to prevent heat for reaction from being lost from the body.

7 is a mixed gas intake port, 8 is a reformed gas chamber, 9 is a reformed gas exhaust port, and 10 is a combustion exhaust gas exhaust port.

A burner 11 is a heating means for heating the reactant and causing a steam reforming reaction by catalytic action.

A steam super heater 12 heats water vapor. Reference numeral 13 denotes an ejector that mixes natural gas and heated steam and increases the pressure. 14
is an exhaust gas cooler.

Next, the operation of the reformer 1 having such a configuration and its peripheral equipment will be explained.

The natural gas and the steam heated by the steam super heater 12 are mixed by the ejector 13.
The voltage is boosted and sent to the reformer 1. The mixed gas sucked in from the intake port 7 of the re-former 1 is heated by the burner 11 in the process of passing from the outer tube 2 to the inner tube 3 of the reaction tube, and undergoes a steam reforming reaction under the action of the catalyst 4, containing a large amount of hydrogen. Becomes reformed gas. The reformed gas after the reaction is sent from the reformed gas chamber 8 through the exhaust port 9 to necessary equipment, such as the fuel cell main body. The combustion exhaust gas is exhausted from the exhaust port 10 and used for hot water supply, air conditioning, etc.

As can be seen from Fig. 1, in the conventional re-boomer, the high temperature (approximately 800 to 1400 degrees Celsius) combustion gas from the burner 11 comes into direct contact with the heat insulating material 6 on the inner wall of the body 5, so there is no heat loss to the outside of the body 5. It had many shortcomings.

In addition, in a system required for the reheater 1, such as a fuel cell system, it is necessary to separately provide a steam superheater 12 in order to operate the refrigerant 1, and a high temperature (approximately 600 to 800°C) combustion Since it is necessary to provide an exhaust gas cooler 14 to utilize the heat of the exhaust gas, there are drawbacks such as an increase in the installation space of the system and a large heat loss.

[Purpose of the invention]

The present invention was made to solve the problems of the prior art, and improves thermal efficiency by combining a refohmer and a heat exchanger, reduces the installation space of the system in which the refohmer is used, and reduces heat loss. The purpose is to provide a highly efficient re-former with a small amount.

[Summary of the Invention] The configuration of the re-former according to the present invention includes: a reaction tube that heats a mixed gas of natural gas and steam to cause a steam reforming reaction by the action of a catalyst; a heating means that heats the reaction tube; A re-former consisting of a body housing the reaction tube and lined with a heat insulating material, in which a heat exchanger surrounding the reaction tube is provided,
More specifically, a shielding cylinder is provided around the reaction tube, a space between the shielding cylinder and the body is used as an exhaust heat recovery area, and an annular heat exchanger is arranged in this area.

Additionally, by arranging a heat exchanger to cover the high-temperature reaction part inside the re-former, it is possible to superheat the steam necessary for the reforming reaction and recover heat from the combustion exhaust gas. The aim is to reduce heat loss.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

FIG. 2 is a longitudinal cross-sectional view of a re-former according to an embodiment of the present invention, and a system diagram showing peripheral equipment and gas flows. In FIG. 2, the same reference numerals as in FIG. 1 indicate parts equivalent to the prior art. Further, solid line arrows indicate the flow of natural gas, dashed line arrows indicate the flow of steam, double-dashed line arrows indicate the combustion gas or combustion exhaust gas, and thick solid line arrows indicate the flow of reformed gas.

In the figure, reference numeral 20 denotes a reformer, in which a reaction tube consisting of an outer tube 2, an inner tube 3, and a catalyst 4 is disposed in the center. Reference numeral 21 denotes a shielding cylinder, which is arranged around the reaction tube so as to surround the reaction tube, and is configured to partition the reaction tube external heat region 22 and the exhaust heat recovery region 23.

24 is a heat exchanger, which connects the shielding cylinder 21 and the heat insulating material 1.
It is disposed in the area between the body 15 lined with the heat exchanger 6, that is, the exhaust heat recovery area 23, and is, in short, an annular heat exchanger that surrounds the reaction tube. 17 is a water vapor inlet, and heat exchanger 2
It is directly connected to 4. 18 is a heated steam exhaust port, which is directly connected to the heat exchanger 24. That is, the pipes constituting the annular heat exchanger 24 are connected to the pipes (dotted line portion) through which steam flows before mixing of natural gas and steam. Reference numeral 19 denotes an exhaust port for combustion exhaust gas, which opens into the exhaust heat recovery area 23 . The other configurations are the same as those of the prior art, so the explanation will be omitted.

Next, the operation of the reformer 20 having such a configuration and its peripheral equipment will be explained.

The reaction in the reaction tube is similar to the prior art described above. The mixed gas of natural gas and water vapor sucked in from the intake port 7 of the re-former 20 passes through the burner 11 in the process of traveling from the outer tube 2 to the inner tube 3 of the reaction tube.
The catalyst 4 causes a steam reforming reaction, resulting in a reformed gas containing a large amount of hydrogen. The reformed gas is sent from the reformed gas chamber 8 through an exhaust port 9 to a necessary device, such as a fuel cell.

On the other hand, water vapor, which was conventionally heated by a steam superheater, is introduced from the air intake port 17 of the reheater 20 to the annular heat exchanger 24 disposed in the exhaust heat recovery area 23 without using the steam superheater in this embodiment. The water vapor then reaches a high temperature (approximately 600 to 800°C) flowing from the heat area 22 outside the reaction tube to the exhaust heat recovery area 23 as shown by the double-dashed chain arrow in FIG.
exchanges heat with the combustion exhaust gas and is superheated,
The gas is guided as indicated by the dashed arrow, and is mixed with natural gas and pressurized by the ejector 13. The mixed gas is sent to the reformer 20 and undergoes the steam reforming reaction described above.

The heat necessary for the reaction at this time is provided by the burner 11, and the combustion gas from the burner 11 is guided to the exhaust heat recovery area 23 provided outside the shielding tube 21 after heat exchange with the reaction tube. Annular heat exchanger 2
After exchanging heat with 4 and losing heat and becoming low temperature, it is discharged to the outside of the re-former 20 from the exhaust port 19. Combustion exhaust gas is used for hot water heating, air conditioning, etc.

According to this embodiment, since superheating of the steam necessary for the reaction and exhaust heat recovery from the combustion exhaust gas are performed simultaneously in the exhaust heat recovery area 23 of the refoamer 20, it is possible to There is no need to separately provide an exhaust gas cooler for recovering exhaust heat.

As a result, a fuel cell system or the like that uses a re-former can be made more compact than before, and the thermal efficiency of the system is also increased due to the reduction in device surface area.

Further, according to this embodiment, the combustion exhaust gas comes into contact with the inside of the body 15 of the refoamer in a state where the temperature is lowest. Therefore, rifoma 2
Since the temperature difference between the outside and the inside of the heat insulating material 16 is smaller than in the past, there is less heat loss. As a result, it is possible to improve the efficiency of the system.

In the above-mentioned embodiment, an example of a reheater used in a commercial fuel cell system has been described, but the present invention is not limited to only a fuel cell system, but can be applied to a general purpose refrigerant used in a system that can be expected to have the same effect. It is something like that.

〔Effect of the invention〕

As described above, according to the present invention, thermal efficiency is improved by combining a refohmer with a heat exchanger, the installation space of a system in which the refohmer is used is reduced, and a highly efficient refohmer with low heat loss is provided. can do.

[Brief explanation of drawings]

Figure 1 is a longitudinal cross-sectional view of a conventional re-former and a system diagram showing peripheral equipment and gas flow, and Figure 2 is a
FIG. 1 is a longitudinal cross-sectional view of a re-former according to an embodiment of the present invention, and a system diagram showing peripheral equipment and gas flows. 2... Outer tube (reaction tube), 3... Inner tube (reaction tube),
4... Catalyst, 7... Inlet port for mixed gas, 9... Exhaust port for reformed gas, 11... Burner, 13... Ejector, 15... Body, 16... Insulation material, 17...
Water vapor intake port, 18... Water vapor exhaust port, 19
...Combustion exhaust gas exhaust port, 20...Refoma,
21... Shield cylinder, 22... Reaction tube external heat area, 23
...Exhaust heat recovery area, 24...Annular heat exchanger.

Claims (1)

[Scope of Claims] 1. A reaction tube that heats a mixed gas of natural gas and steam to cause a steam reforming reaction by the action of a catalyst, a heating means that heats the reaction tube, and a heat insulated tube that houses the reaction tube. 1. A reefer comprising a body lined with a material, characterized in that a heat exchanger surrounding the reaction tube is provided. 2. In what is stated in claim 1,
A re-former is a system in which a shielding tube is provided around the reaction tube, the space between the shielding tube and the body serves as an exhaust heat recovery area, and an annular heat exchanger is placed in that area. 3. A re-former according to either claim 1 or 2, in which piping constituting a heat exchanger is connected to piping through which steam flows before mixing natural gas and steam. . 4. The refoamer according to claim 1 or 3, wherein an exhaust port for combustion exhaust gas is opened in an exhaust heat recovery area provided with a heat exchanger.