JPH0711136Y2 - Fuel cell fuel reformer - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] This invention is incorporated into a fuel cell power generation system, reforms a raw fuel gas composed of methanol and steam into a hydrogen-rich reformed gas, and supplies it to a fuel cell. And a structure of a fuel reformer.

[Conventional technology]

In a small fuel cell power generation system, the fuel reformer that generates hydrogen-rich reformed gas to be supplied to the fuel cell has a steam reforming reaction temperature of 200 ° C or more compared to a reformer that uses natural gas as a raw fuel. Attention is focused on a steam reformer (hereinafter referred to as reformer) that uses methanol as a raw fuel, which has a low temperature of 300 ° C and does not require a desulfurizer or a transformer, and therefore has a short preheating time at the time of starting and is compact. ing.

FIG. 2 is a side sectional view showing a conventional structure of a reformer. In the figure, a bottomed cylindrical furnace body 1 is coaxial with this and an inner cylinder 2 having a gap length G between the bottom and the bottom plate. A burner 3 supported by the central portion of the inner cylinder 2 from the upper lid 1B is provided, and a mixed gas of the fuel gas 8A flowing from the inlet 3A and the combustion-supporting air 8B flowing from the inlet 3B is burned in the burner 3 and is directed downward. Flame 8F and high temperature combustion (exhaust) gas 8C are generated. The combustion gas 8C is guided by the combustion cylinder 3G and the inner cylinder 2 to reach the furnace bottom, and a part of the combustion gas 8C is formed outside the inner cylinder 2 with the combustion gas 8S flowing into the exhaust pipe 4 opened at the center of the furnace bottom. It splits into the combustion gas 8R which flows through the reverse passage 5 and flows into the exhaust pipe 5B opened at the upper part thereof. The split ratio of the combustion gases 8R and 8S is mainly controlled by the electromagnetic damper 4A provided in the exhaust pipe 4, and the thermal energy of the high temperature combustion exhaust gas S passing through the electromagnetic damper 4A is, for example, a vaporizer of raw fuel and water. It is used as a heat source for 4B and produces a raw fuel gas 9A with a predetermined steam ratio.

On the other hand, 6 is a spiral tube which is coaxially arranged inside the inner cylinder 2 and is heated by the flame 8F emitted by the burner 3 or the high-temperature combustion gas 8C, for example, the raw fuel gas 9A produced by the vaporizer 4B.
From the inlet 6A, reheated to a predetermined temperature, and then supplied to the lower part of the reforming reaction tube 7 provided in the reverse passage 5 outside the inner cylinder. The reforming reaction tube 7 comprises a double tubular container provided in the reverse passage 5 of the combustion gas between the inner cylinder 2 and the furnace body 1 or a plurality of parallel tubes having manifolds at the upper and lower ends,
A cylindrical container or a parallel pipe is filled with a reforming catalyst 7B which is a steam reforming catalyst such as a copper-zinc system, a copper-chrome system, or a third component added to these, and this reforming catalyst layer 7B The steam reforming reaction, which is an endothermic reaction that occurs with the raw fuel gas 9A passing upward, uses the high temperature combustion gas 8R that heats the reforming reaction tube 7 from the outside as a heat source, and the temperature required for the reaction.
By maintaining the temperature at 200 ° C. to 300 ° C., the hydrogen-rich reformed gas 10 is supplied to the fuel cell (not shown) through the reformed gas supply system 7C opened at the upper part of the reforming tube.

[Problems to be solved by the device]

In the conventional apparatus, the temperature control of the reforming reaction tube 7 and the vaporizer 4B is performed mainly by supplying the fuel gas 8A and the combustion-supporting air 8B to the burner 3 and the combustion gas 8R, 8 by the electromagnetic damper 4A.
When the cold reformer and the fuel cell are to be started, the fuel consumption of the burner 3 is temporarily increased rapidly, and the carburetor 4B and the flexible pipe are controlled.
It is required to rapidly heat 6, 6 and the reforming reaction tube 7 to their respective operating temperatures to shorten the power generation standby time. In such a state, the flame 8F emitted by the burner may extend for a long time to reach the electromagnetic damper, and the electromagnetic damper 4A
For example, the ball valve-shaped opening / closing mechanism is directly affected by the heat of the flame 8F and becomes a red heat state, which easily causes a problem that the movable part is in a restricted state and its opening control becomes difficult. Then, there arises a problem that it becomes impossible to control the split flow of 8S, that is, the temperature control of the vaporizer 4B and the reforming reaction tube 7.

An object of the present invention is to smooth the distribution control of the combustion gas at the time of starting by eliminating the thermal influence of the flame on the electromagnetic damper.

[Means for Solving the Problems]

In order to solve the above problems, according to the present invention, a tubular furnace body that supports a burner that emits flames and high-temperature combustion gas downward in a central portion of an upper lid has a coaxial inner tube, and The combustion gas that is guided and reaches the bottom of the furnace is diverted into the exhaust pipe that penetrates the bottom of the furnace body and the reverse passage that passes through the outside of the inner cylinder, and is discharged, and the raw fuel gas with a predetermined steam ratio is burned. Which is heated by a flexible pipe disposed below the exhaust gas and is sent out from the upper portion of the reforming reaction tube toward the fuel cell as reformed gas which is steam-reformed by the reforming reaction tube disposed in the reverse passage. Is provided inside the flexible tube with an extension means for the combustion gas passage, which comprises an extension pipe portion projecting toward the burner by a predetermined length and a cap portion that holds the extension pipe portion from the opening side while holding a gap. I shall.

[Action]

A means for extending a combustion exhaust gas passage, which comprises an extension pipe portion of an exhaust pipe opened at the bottom of the furnace body, and a bottomed cylindrical cap portion that covers the extension pipe portion from the opening side while holding a gap that serves as a passage for combustion exhaust gas, is provided. By arranging it further inside the flexible pipe that is coaxial with the inner cylinder, the flame lengthened by increasing the fuel consumption of the burner first spreads to the inner wall surface side of the inner cylinder on the upper surface of the cap, And the side wall of the cap, heat is transferred to the flexible pipe, which lowers the flame temperature, and the bottom edge of the cap folds back into the gap between the extension pipe to extinguish the flame and further cool combustion. Since the exhaust gas flows into the exhaust pipe where the electromagnetic damper is arranged through the extension pipe section, the operational congestion of the electromagnetic damper caused by the direct impact of the flame on the electromagnetic damper is eliminated. The distribution of combustion gas to the carburetor side is smoothed, and at the same time, the lower parts of the flexible pipe and the reforming reaction pipe are heated by the higher temperature combustion gas, and steam reforming is performed efficiently, which results in combustion reforming. The time required to start the vessel can be shortened.

〔Example〕

 The present invention will be described below based on embodiments.

FIG. 1 is a side sectional view showing an apparatus according to an embodiment of the present invention,
The same functional parts as those of the conventional device are designated by the same reference numerals and detailed description thereof will be omitted. In the figure, reference numeral 20 is an extension means of a combustion gas passage, and an extension pipe portion 21 in which an exhaust pipe 4 opened at a central portion of a bottom portion of a furnace body 1 is protruded toward a burner 3 by a predetermined length, and the extension pipe portion 21. It is configured with a bottomed cylindrical cap portion 22 that opens downwardly covering the opening side, and a gap 23 that serves as a passage for combustion gas is held between the extension pipe portion 21 and the cap portion 22, The flexible pipe 6 is arranged so as to surround the outer periphery of the cap portion 22, and a gap 24 serving as a combustion gas passage is also held between the flexible pipe 6 and the inner cylinder 2 surrounding the flexible pipe 6. Further, a space serving as a passage for the combustion gas is maintained between the lower edge of the combustion cylinder 3G of the burner 3 and the upper surface of the cap portion 22. In addition, the length of the extension pipe portion 21 is determined to be a dimension that can maintain a space serving as a combustion gas passage between the upper edge of the extension pipe portion 21 and the cap portion.

When the length of the flame 8F generated by temporarily increasing the fuel consumption of the burner is increased at the time of starting the apparatus of the embodiment as described above, the flame 8F is on the upper surface of the cap portion 22 on the inner cylinder 2 side. And is cooled by supplying heat energy to the raw fuel gas 9A having a predetermined water vapor ratio passing through the flexible tube 6 in the process of passing through the void 24, and is turned back to the void 23 side at the lower edge of the cap portion 22. Since the flame is blown out to become high-temperature combustion gas 28S and flows into the exhaust pipe 4 via the extension pipe portion 21, the temperature of the combustion gas 28S is appropriate when passing through the electromagnetic damper 4A arranged in the exhaust pipe 4. The negative effects such as restraint caused by the electromagnetic damper being red-heated are eliminated. Therefore, the opening of the electromagnetic damper 4A is smoothly controlled according to the control current applied to the magnet coil, so that the combustion gas to the carburetor 4B side
The branch amount of 28S and the combustion gas 28R to the reverse passage 5 side can be controlled at a desired ratio.

Further, the flexible pipe 6 for reheating the raw fuel gas 9A and the lower portion of the reforming reaction pipe 7 into which the reheated raw fuel gas 9A flows are heated by the high-temperature combustion gas 8C or 22R containing flame, Since the heat energy required for the steam reforming reaction in the high quality catalyst layer 7B can be efficiently supplied, the preheating time of the reformer at the time of starting is shortened, and the reformed gas 10 can be supplied to the fuel cell (not shown) early. it can.

[Effect of device]

As described above, this invention is composed of an extension pipe portion, which extends an exhaust pipe having an electromagnetic damper opened at the bottom of the furnace body toward the burner, and a cap portion which holds a gap and covers it from the opening side. The gas passage extension means is provided inside the flexible pipe for reheating the raw fuel gas. As a result, the flame of the burner that has been elongated for a long time at the time of starting is guided to the gap where the flexible pipe is arranged on the upper surface of the cap portion to supply heat energy to the raw fuel gas, and between the extension pipe portion at the lower edge of the cap portion. Since the flame is extinguished and flows into the exhaust pipe at the time of turning back to the gap, the problem that the flame restrains the damper due to the red heat of the electromagnetic damper in the conventional device is eliminated. The function of the damper that divides the flow into the reverse passage and the carburetor arranged downstream of the damper is smoothed, and the lower part of the flexible pipe and the reforming reaction pipe is efficiently heated by the high-temperature combustion gas including fire. Therefore, it is possible to provide the fuel reformer of the fuel cell having the starting characteristic in which the preheating time at the time of starting is shortened.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an apparatus according to an embodiment of the present invention, and FIG. 2 is a side sectional view showing a conventional apparatus. 1 ... Furnace body, 2 ... Inner cylinder, 3 ... Burner, 4 ... Discharge pipe, 4A ... Electromagnetic damper, 4B ... Vaporizer, 5 ... Reverse passage, 6 ... Snake pipe, 7 ... Reforming reaction tube, 7B ... Reforming catalyst layer, 8,28 ... Combustion gas, 8F ... Flame, 9A ... Raw fuel gas, 10 ... Reforming gas, 20 ... Combustion gas passage extension means,
21 …… extension pipe part, 22 …… cap part, 23,24 …… void.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A cylindrical furnace body that supports a burner that emits flames and high-temperature combustion gas downward at the center of the upper lid has a coaxial inner cylinder, and the combustion reaches the furnace bottom by being guided by the inner cylinder. The gas is diverted and discharged into an exhaust pipe that penetrates the bottom of the furnace body and a reverse passage that passes outside the inner cylinder, and the raw fuel gas with a prescribed steam ratio is heated by a serpentine pipe arranged below the burner. In the case where the reformed reaction tube arranged in the reverse passage sends the reformed gas steam-reformed from the upper portion of the reforming reaction tube toward the fuel cell, the exhaust pipe is directed toward the burner by a predetermined length. A fuel cell is provided with an extending means for a combustion gas passage, which is formed by a protruding extension pipe portion and a cap portion which holds the extension pipe portion with a gap and covers the opening from the opening side. Fuel reformer.