KR20110037324A - Steam generator for fuel cell - Google Patents

Abstract

PURPOSE: A steam generator for a fuel cell is provided to solve the performance degradation and lifetime reduction caused by the unbalance of vapor generation by producing stably vapor even if a heating source is varied. CONSTITUTION: A steam generator for a fuel cell comprises a heat supply unit and a heat absorbing unit. The heat supply unit comprises an inlet, an outlet and a flow channel for high temperature gas. The heat absorbing unit comprises an water inlet, a vapor outlet, and an flow channel(230) for water or vapor, wherein the flow channel heat-exchanges with high temperature gas. The flow channel for water or vapor includes a first pipe(231) through which water and vapor are passed and a second pipe(232) filled with a phase change material(232a).

Description

Steam generator for fuel cell {Steam generator for fuel cell}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell, and more particularly, to a steam generator for supplying heat from a hot gas and changing a state from water to steam in order to provide a steam reforming reaction of a fuel such as methane (CH4). It is about.

A fuel cell is a cell that directly converts chemical energy generated by oxidation of fuel into electrical energy. Although it is a kind of power generation device, in terms of using a redox reaction, it is basically the same as a normal chemical cell, but unlike a chemical cell that performs a battery reaction in a closed system, the reactants are continuously supplied from the outside, and the reaction product is outside the system. The difference is that it is removed.

These fuel cells are regarded as eco-friendly technologies because they emit little pollutants, and because they can use various fuels besides petroleum, they are suggested as alternatives to reduce the problem of resource depletion. However, although the cost of fuel consumed to charge the battery is cheaper than the cost of charging other secondary batteries, so far, the price of the jersey itself is expensive.

The fuel cell is a polymer electrolyte type (PEMFC), direct methanol type (DMFC), phosphoric acid type (PAFC), alkali type (AFC), molten carbonate type (MCFC), solid oxide type ( SOFC) and the like.

1 is a block diagram showing the concept of the fuel cell as described above. Referring to the drawings, a typical fuel cell includes a stack 10, a balance of plant 20, and a fuel processor 30.

The stack 10 is a power generator that directly converts chemical energy of a hydrogen raw material into electrical energy to generate a direct current, and serves as a power supply. The BOP 20 is a device that supplies fuel required for a fuel cell and plays a role for smoothly operating the system.

The fuel converter 30 is a device for producing hydrogen used in a fuel cell from fuel, natural gas, methanol, coal, petroleum, etc., and is also commonly referred to as a reformer.

The reformer requires a steam generator because it needs to supply high temperature steam for reforming the fuel. Here, a high temperature heat source is required to heat the liquid water to generate high temperature steam, and the heat source has various methods such as using solar heat or high temperature waste heat.

For example, in the case of a steam generator of a molten carbonate fuel cell (MCFC), a heat recovery steam generator (HRSG) that uses high-temperature waste heat through heat exchange may be used. Therefore, there is a need for a technology capable of effectively recovering heat from high temperature waste heat.

However, the molten carbonate fuel cell (MCFC), due to the wide range of load fluctuations, it is necessary to supply appropriate water vapor inside the stack to cope with this. If the condition and supply of water vapor are not appropriate, this will result in a deterioration of the overall fuel cell as well as greatly shortening the life of the system. Therefore, there is a need for a steam generator that can stably supply steam even if the heat source is changed.

The present invention was created in order to meet the above-mentioned needs, so that even when the heat source fluctuates, it is possible to stably generate steam, thereby reducing fuel cell performance and shortening the lifespan of fuel cells due to uneven steam generation. The object is to provide a generator.

The present invention is provided with an inlet and outlet of the hot gas, the heat supply unit is formed therein the movement path of the hot gas; And water or steam communicating with the inlet of the water provided on one side of the heat supply unit, the outlet of the steam provided on the other side of the heat supply unit, the inlet and the outlet, and disposed on the moving path in the heat supply unit to exchange heat with the hot gas. And a heat absorbing part including a flow pipe of the water or steam, wherein the water or steam flow pipe includes a first pipe through which water or water vapor passes, and a hot gas flowing around the outside of the first pipe and flowing through a moving path of the heat supply part. Provided is a steam generator for a fuel cell including a second pipe filled with a phase change material (PCM) whose state changes in response to temperature.

Here, preferably, the phase change material is M 2 Co 3, and M may be an alkali metal.

In addition, M may be at least one selected from lithium (Li), Na (sodium) and K (potassium).

According to the steam generator for fuel cells according to the present invention, since it is possible to stably supply heat by using latent heat and sensible heat of a phase change material, it is possible to solve the non-uniformity of steam generation due to fluctuation of the heat source and to generate steam. The flow rate control for the purpose is simplified.

In addition, it is possible to prevent the performance degradation of the entire fuel cell and the shortening of the life of the system, which may occur due to improper steam condition and flow rate.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the present specification and claims should not be construed as being limited to the common or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

2 is a configuration diagram of a steam generator according to an embodiment of the present invention, Figure 3 is a partial perspective view showing a part of the flow tube of water or steam shown in Figure 2, Figure 4 is applied to the phase change material shown in FIG. It is a comparative graph showing the temperature change of the flow pipe depending on the presence or absence.

2 and 3, the steam generator according to the embodiment of the present invention includes a heat supply unit 100 and a heat absorber 200 that absorbs heat from the heat supply unit 100.

The heat supply part 100 is provided with an inlet 110 and an outlet 120 of hot gas. In addition, a moving path 130 through which the hot gas flowing into the inlet 110 flows is formed, and the hot gas flowing through the moving path 130 flows out through the outlet 120. The hot gas may be a waste heat gas that can be normally discarded after performing its original function, such as combustion gas.

The heat absorbing part 200 includes an inlet port 210 provided at one side of the heat supply unit 100 to introduce water and a discharge port 220 provided at the other side of the heat supply unit 100 to discharge water vapor. In addition, the heat absorbing part 200 includes a flow pipe 230 for communicating the inlet 210 and the outlet 220. The flow tube 230 is disposed on the movement path 130 formed inside the heat supply unit 100 flows water or steam that exchanges heat with hot gas.

In the embodiment of the present invention as described above, the flow pipe 230, has a double pipe structure including a first pipe 231, and a second pipe (232).

The first pipe 231 passes through water or steam heated in the middle. The second tube 232 surrounds the outside of the first tube 231. Here, the inside of the second pipe 232 surrounding the outside of the first pipe 231 is filled with a phase change material (PCM; 232a). The phase change material is a material whose state changes in response to the temperature of the hot gas flowing through the movement path 130 of the heat supply part 100.

M2Co3 may be used as the phase change material 232a as described above. Here, M is an alkali metal, and may be at least one selected from lithium (Li), Na (sodium), and K (potassium).

FIG. 4 is a comparative graph showing a temperature change of a flow tube depending on whether or not the phase change material shown in FIG. 3 is applied. Here, Li 2 Co 3 was used as the phase change material 232a. As shown, it can be seen that the case where the phase change material (Li2Co3) is filled in the double tube structure (A) is maintained at a high temperature for longer than when the phase change material is not used in the single tube structure (B).

That is, by using the latent heat and sensible heat of the phase change material, it is possible to solve the non-uniformity of the generation of steam caused by the fluctuation of the heat source, and to simplify the flow rate control for generating the steam. In addition, the problem that the performance of the entire fuel cell is reduced or the life of the system can be solved.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a block diagram showing the concept of a general fuel cell,

2 is a configuration diagram of a steam generator according to an embodiment of the present invention;

3 is a partial perspective view showing a part of a flow tube of water or steam shown in FIG.

FIG. 4 is a comparative graph showing a temperature change of a flow tube depending on whether or not the phase change material shown in FIG. 3 is applied.

<Brief description of the main parts of the drawing>

100: heat supply unit 110: inlet

120: exit 130: moving path

200: heat absorption portion 210: inlet

220: outlet 230: flow pipe

231: Hall 1 232: Hall 2

232a: phase change material

Claims (3)

A heat supply part (100) having an inlet (110) and an outlet (120) of hot gas and having a moving path (130) of hot gas therein; And The inlet 210 of the water provided on one side of the heat supply unit 100 and the outlet 220 of the water vapor provided on the other side of the heat supply unit 100, the inlet 210 and the outlet 220 in communication with the hot air The heat absorbing part 200 is disposed on the moving path 130 in the feed part 100 and includes a heat absorbing part 200 including a flow pipe 230 of water or steam which exchanges heat with the hot gas. 230, A first pipe 231 through which water or steam passes, Phae Change Material (PCM) 232a surrounding the outside of the first pipe 231 and whose state changes in response to the temperature of the hot gas flowing through the moving path 130 of the heat supply part 100. Steam generator for a fuel cell comprising a second pipe (232) filled with. The method according to claim 1, The phase change material (232a) is M2Co3, wherein M is an alkali metal steam generator for a fuel cell. The method according to claim 1 or 2, Wherein M is at least one selected from lithium (Li), Na (sodium) and K (potassium) steam generator for fuel cells.

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