JPH02139871A - Activation method for fuel cell power generation system - Google Patents

Abstract

PURPOSE:To keep a temperature gradient small within the plane of a full cell during a temperature rise and take out power early even at a low temperature via the earlier activation of the cell at the upstream side of a circulation passage by dividing the cell proper into a pair of cell stacks integrated with a heat exchanger. CONSTITUTION:In a temperature rise at cell activation, an activation burner 4 is supplied with a mixed solution of a reform in a reformer 7 and methanol from a tank 8 and atomized for burning, and heated air is thereby circulated for supply to a cell proper 1. The heated air after cooled is exhausted from a damper 5 and combustion air is taken from an intake 6. Flue gas 9 from the reformer 7 flows into a heat exchanger 2 between both stacks 1, and 12, and a heat exchange process takes place with heated gas cooled with the upstream side stack 11, while heated gas having a high temperature flows into the downstream side stack 12. Combustion at a burner 4 is stopped and the introduction of the flue gas to the heat exchanger 2 is shut with a valve 10. In addition, another valve 11 is opened and fresh air drawn with a blower 12 is introduced to the heat exchanger 2, thereby preheating circulation air. Then, the preheated air is fed to the stack 11 and gas from the reformer 7 is supplied, thereby raising the temperature via cell reaction.

Description

[Detailed Description of the Invention] l(l Industrial Field of Application) The present invention relates to a startup method in a phosphoric acid fuel cell power generation system used in remote mountainous areas or as a portable independent power source, and in particular to temperature rise at the time of battery startup. .

(b) Conventional technology Phosphoric acid fuel cells are normally operated at around 180°C, but when they are not in use, they are stored at ambient temperatures (-20°C to 40°C).

When starting a battery, a method is generally used in which the battery body is heated and then the temperature is raised to a specified operating temperature using the heat of battery reaction.

The conventional temperature raising method uses a cooling air circulation path 0 as shown in Figure 3.
Air is heated by a starting burner (b) located in the battery, and this heated air is circulated to raise the temperature of the battery body (b). A gradient occurs and the difference between the maximum temperature curve and the minimum temperature curve becomes large, and the power generated by the battery depends on the minimum temperature l, so that the startup time of the battery becomes longer. Furthermore, since the temperature of the heated air is limited to about 200° C. due to the thermal tolerance of the cell constituent materials, increasing the temperature increase rate requires an increase in the blower capacity and burner fuel. In addition, there are various problems such as the need for a separate preheater (c) to preheat the reaction air supplied to the battery, especially in cold regions.

ej Problems to be Solved by the Invention The present invention divides a battery with a specified capacity (for example, 10KW) into two batteries with half the capacity (5KW), thereby reducing the temperature gradient within the battery surface when the temperature rises. By starting up the batteries on the upstream side of the circulation path first, half the capacity of power can be quickly extracted even from extremely low temperatures. In this way, the above-mentioned problems are solved.

B) Means for Solving the Problems The present invention provides a battery main body consisting of a pair of battery stacks integrated on opposing cooling air circulation surfaces via a heat exchanger, which is interposed in a circulation path having a blower. When the temperature of the battery body rises, the combustion of the starting burner supplies air heated by the gas to the circulation path, and the flue gas of the reformer is introduced as a heating medium to the heat exchanger, so that the upstream stack After raising the temperature to a temperature at which the reaction is possible, the combustion of the burner is stopped and the introduction of flue gas to the heat exchanger is cut off, and outside air is introduced instead and preheated by the exhaust heat of the stack on the upstream side. The preheated air is supplied as reaction air and the gas generated from the reformer is supplied as fuel gas to start raising the temperature of the upstream stack due to the heat of cell reaction, and when this stack reaches the specified operating temperature, the generated power is partially used. This is a startup method for a fuel cell power generation system in which power is supplied to the load, and then the power generated by the downstream stack is supplied to the entire load in parallel with the power generated by the upstream stack.

(E) Function In the present invention, the heat capacity of each of the pair of battery stacks integrated via the heat exchanger is halved, so the upstream stack rises first to handle a partial load, for example, the fuel cell is used as the power source. It can operate the air conditioner in the transmitter/receiver storage room, and can supply power to the entire load by adding power from the downstream stack that starts up later, reducing start-up time as an independent power source, especially in extremely cold regions. be able to.

In addition, the heat exchanger interposed between the pair of stacks introduces the flue gas from the reformer when the temperature rises, raises the temperature of the heated air sent from the upstream stack to the downstream stack, and thereby raises the temperature of the downstream stack. At the same time, after raising the temperature of the upstream stack to a temperature that allows the battery to react, low-temperature outside air is introduced instead of flue gas, and this is preheated by the high-temperature air that removes heat from the upstream stack and used as reaction air. Furthermore, when both stacks are operating, the low temperature air introduced into the heat exchanger removes the reaction heat from the upstream stack and cools the heated cooling air, which is then sent to the downstream stack, improving cooling performance. The air volume of the blower can be reduced.

(f) Embodiment Figure 1 shows a flow diagram of the fuel cell power generation system of the present invention, in which the battery main body (1) is a pair of battery stacks integrated on opposing cooling air circulation surfaces via a heat exchanger (2). (11)
The cooling passage for both stacks (11x12) is common, but the supply passages for each reaction gas (fuel gas and air) are provided independently.
) is interposed in a cooling air circulation path C having a circulation blower (3), a starting burner (4), an exhaust damper (5), and an intake port (6). ) is supplied with fuel, such as a methanol mixture for reforming and combustion in the reformer (7), from the tank (8) and is spray-burned, and air heated to about 200°C is circulated and supplied to the battery body (1). do.

In this case, the flue gas (9) of the reformer (7) is introduced into the heat exchanger (21) interposed between the heating side stack (11) (1□) whose temperature has decreased due to heat being taken away by the battery body. It exchanges heat with the heated gas whose temperature has been lowered in the upstream stack (11), raises the temperature of this heated gas, and sends it to the downstream stack (1□).

Since the battery body (1) is divided into two parts in this way, the heat capacity of each stack is halved, and as shown in Figure 3, the ambient temperature -
Each stack (11) (1) by the above heating method from 20°C
2) temperature increase characteristics (P)Q are shown.

Compared to the downstream stack (1□), the upstream stack (1,) has a temperature that can be increased by battery reaction heat (approximately 100°C).
The time it takes to reach is significantly reduced. Temperature at the start of heating (
When the ambient temperature (ambient temperature) is -20°C as shown in FIG. 3, the upstream stack (1,) reaches 100°C in about 15 minutes.

In this state, the combustion of the starting burner (4) is stopped and the load temperature rise of the upstream stack (11) is started, but first, the introduction of flue gas to the heat exchanger (2) is shut off with the valve αυ. At the same time, the valve α° C. is opened, and the outside air sucked in by the reaction air supply blower (2) is introduced into the heat exchanger [2+, preheated with circulating air, and supplied to the upstream stack (11) as post-reaction air.

Similarly, the gas vaporized and reformed in the reformer (7) is supplied as fuel gas, and the temperature starts to rise due to the heat of cell reaction. The load temperature rise is efficient, so the specified operating temperature (approximately 180 ~
200℃), and half the output (5K) of the battery itself (11
W) activates the air conditioner in a load such as a transmitter/receiver storage room to warm the room.

The temperature of the downstream stack (12) continues to rise with the cooling air that has been heated to about 180°C by taking away the heat.

When the downstream stack (1□) reaches a temperature at which the battery can react within 30 minutes of starting, the temperature rises due to the heat of battery reaction as described above and reaches the specified operating temperature.

In this way, the power generated by the downstream stack (12) is connected in parallel with the upstream stack (11), resulting in a full load (10KW).
to supply power.

During normal operation of both stacks (1,) (1□), circulating cooling air cools each stack and maintains it at the specified operating temperature. In this case, the cooling air whose temperature has been raised by cooling the upstream stack (1,) is cooled by the outside air introduced into the heat exchanger (21) and then sent to the downstream stack (1,). )
Temperature control is performed by discharging a portion of the exhaust cooling air whose temperature has increased by adjusting the damper (5) to the outside of the system, and at the same time introducing cold outside air from the inlet (6) into the circulation path.

(G) Effects of the Invention As described above, according to the present invention, the battery main body is divided into a pair of integrated battery stacks via a heat exchanger, so the heat capacity of each stack is halved, and circulation during heating is reduced. The stack on the upstream side of the path starts up first and supplies power to partial loads in a short time, and the stack on the downstream side starts up later and can supply power to the entire load, making it especially useful as an independent power source in extremely cold regions. This is advantageous in reducing startup time.

In addition, the heat exchanger interposed between the stacks compensates for the temperature drop of the heated air by introducing the flue gas of the reformer when the temperature rises due to the heated circulating air, and also introduces outside air when the temperature rises due to the heat of battery reaction. Allows preheating of reaction air. Furthermore, when both stacks are in operation, the reaction heat of the upstream stack is taken away and the temperature of the heated cooling air is lowered, improving the cooling capacity, so it has features such as being able to reduce the air volume of the blower.

[Brief explanation of the drawing]

Figure 1 is a flow diagram of the fuel cell power generation system of the present invention;
The figure is a temperature rise characteristic diagram of a pair of battery stacks constituting the battery body, and FIG. 3 is a flow diagram of a conventional power generation system. (1)...Battery/main body, (1,)(1□)...Pair of battery stacks, (2)...Heat exchanger, (3)...
・Circulation blower, (4)...starting burner, (7)...
・Reformer, (8)...fuel tank, (9)...flue gas, 5

Claims (1)

[Claims] (1) A battery body consisting of a pair of battery stacks integrated with opposing cooling air circulation surfaces via a heat exchanger is interposed in the cooling air circulation path, and a starting burner when the temperature of the battery body rises. Air heated by combustion gas is circulated and supplied to the circulation path, and flue gas from the reformer is introduced into the heat exchanger as a heating medium, and after the stack on the upstream side is heated to a temperature at which battery reaction is possible. , the combustion of the burner is stopped and the introduction of flue gas to the heat exchanger is cut off, and outside air is introduced instead and preheated by the exhaust heat of the upstream stack, and this is used as reaction air and the reforming air is The gas produced by the reactors is supplied as fuel gas to start raising the temperature of the upstream stack due to the heat of cell reaction.When this stack reaches the specified operating temperature, the generated power is supplied to the partial load, and the startup is delayed. When the downstream stack reaches a specified operating temperature, the generated power is connected in parallel to the upstream stack to supply power to the entire load.