JPS6179856A - Method of starting turbo-compressor - Google Patents

Abstract

PURPOSE:To obtain a stable starting by operating a stabilizing furnace after starting a turbo-compressor by means of a compressed air form a starting compressed-air supply unit when starting a system, and making said turbo- compressor operate by itself by means of the combustion gas from said furnace. CONSTITUTION:When starting a system, first, valves 4, 6, 10 are closed and valves 14, 17 are opened, to start a starting compressed-air supply unit 15. A compressed air form the unit 15 is introduced into a turbine 2a through a compressor 2b, piping 5, a starting bypass piping 16, and a system exhaust gas piping 7, to start a turbo-compressor 2. In this condition, a regulator valve 10 is opened to introduce the compressed air into a stabilizing furnace 9, while fuel is fed from a fuel feeding piping 11 to start the combustion of the stabilizing furnace 9. A combustion exhaust gas produced here is introduced into the turbine 2a together with said compressed air and, when a temp. necessary for the operation of the turbo-compressor 2 by itself is attained, the selector valve 4 is opened to stop said supply unit 15 and make the turbo-compressor 2 operate by itself.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention uses exhaust gas energy from a system to drive a turbine, and supplies the air required by the system by a compressor installed coaxially with the turbine. The present invention relates to a method for starting a turbo compressor system.

[Conventional technology]

This type of turbo compressor aims to effectively recover energy within the system without wastefully discarding the exhaust gas energy of the system, and a typical example is a fuel cell power generation system. This fuel cell power generation system will be described below as an example.

Fuel cell power generation systems have advantages over conventional steam power generation, such as higher efficiency and better environmental protection.
In recent years, development has been actively underway with the aim of putting it into practical use. A fuel cell power generation system consists of a fuel cell body consisting of an air electrode, a fuel electrode, and an electrolyte layer.

A reformer that reforms hydrocarbon fuel such as natural gas and supplies hydrogen gas as fuel to the fuel cell body.

It is equipped with a turbo compressor that supplies air to the fuel cell body and a reformer. The performance of the fuel cell itself shows a tendency to improve as the pressure of the reactant gas increases.

For this reason, the operating pressure of fuel, air, and each reaction gas is, for example, 4
The pressure is maintained at about 6 kg/c+/g. At this time,
Compressing air requires a lot of power.

This power is provided by the turbine of the turbo compressor, which introduces the combustion exhaust gas from the reformer and surplus air from the air electrode of the fuel cell main body. In other words, this turbo compressor recovers the system's exhaust gas energy using a coupin, and supplies the necessary compressed air with a coaxial compressor, thereby recovering power within the system and improving system efficiency. be.

Now, in such a fuel cell power generation system, in order to start the system, it is first necessary to start the turbo compressor, but since system exhaust gas is not available as a driving source in the initial stage, some external energy must be applied. It is necessary to start up the turbo compressor.

For example, two specific conventional methods include:
There is a system disclosed in No. 16685, and the system is shown in FIG. In the figure, (1) is a system including a combustion furnace consisting of a fuel cell body, a reformer, etc.; (2)
) is driven by the exhaust gas from the system (1) and provides the necessary compressed air to the system (1).
a) and a compressor i (2b) arranged coaxially with this turbine (2a).

(3) is the air supply pipe installed on the inlet side of the compressor (2b) of this turbo compressor (2), and (4) is this air supply pipe (
The switching valve (5) is installed on the outlet side of the compressor (2b) and directs the air from the compressor (2b) to the system (3).
1), (6) is the control valve installed in this air supply pipe (5), and (7) is the system (1).
The system exhaust gas piping that guides the exhaust gas from the turbine (2 &) to the turbine (2 &), (8) is the bypass piping that bypasses the air supply piping (5) and the system exhaust gas piping (7), and (9) is installed in this bypass piping (8). (10) is a control valve installed in the bypass pipe (8), which adjusts the amount of air supplied to the auxiliary combustion furnace (9). (11) is a fuel supply pipe that supplies fuel to the auxiliary combustion furnace (9), and (12) is a compressed air supply device for startup.

(13) introduces the air from this starting compressed air supply device (12) to the inlet air supply pipe (3) of the compressor (2b) (introduction pipe, (14) to the introduction pipe (13) on the ζ side. This is the installed switching valve.

Next, the starting operation of the turbo compressor in the conventional system configured as described above will be explained. First, when starting, close the switching valve (4) and regulating valve (6), open the switching valve (14) and regulating valve (10), and discharge compressed air from the starting compressed air supply device (12).

As a result, the compressed air passes through the compressor (2b) and is guided to the auxiliary combustion furnace (9), but at this time, fuel is supplied to the auxiliary combustion furnace (9) from the fuel supply pipe (11) and the auxiliary combustion furnace (9) By burning the compressed air, the compressed air is heated and directly input into the turbine (2&). As the temperature of the compressed air increases, the turbo compressor (2) starts to start up, and at the same time the air pressure increases. When the temperature necessary for self-operation of the turbo compressor (2) is reached, the switching valve (4) is opened, the startup compressed air supply device (12) is stopped, and the switching valve (14) is closed. The turbo compressor (2) shifts to self-operation. This state is, so to speak, a standby state, and air can be sent out at any time as required by the system (1). That is, by opening the control valve (6), compressed air is supplied to the system (1).
At the same time, the compressed air is used for combustion and other purposes in the system (1), and is then led as exhaust gas to the turbine (2a) via the system exhaust gas pipe (7).

However, traditional systems like this.

When starting the turbo compressor (2), the auxiliary combustion furnace (9) is first combusted, and then the turbo compressor (2) is started using the energy of this auxiliary combustion furnace (9). This has the drawback that combustion in the auxiliary combustion furnace (9) is unstable and misfires are likely to occur. That is, in this case, the auxiliary combustion furnace (9) is normally used to increase combustion efficiency.

A direct heating method is used, and the exhaust gas from the combustion of the combustion burner (not shown) installed in the main body of the auxiliary combustion furnace (9) directly flows into the system exhaust gas pipe ``7'' and is fed to the turbine (2a).
). On the other hand, when the turbo compressor (2) starts up, the rotation speed increases quickly.

During a short period of time (for example on the order of a few seconds or less), the pressure of the compressed air on the air supply line (5), the bypass line (8) and the system exhaust gas line (7) increases. At this time,
Combustion in the auxiliary combustion furnace (9) is accompanied by rapid pressure changes, making combustion in the combustion burner unstable and prone to misfires. Therefore, there has been a drawback that stable self-operation of the turbo compressor (2) cannot be achieved.

[Summary of the invention]

This invention was made in view of the drawbacks of the above-mentioned systems, and when the system is started, the startup compressed air supply device is started and the compressed air from the startup compressed air supply device is bypassed without passing through the auxiliary combustion furnace. After the compressed air is fed into the turbine and the turbo compressor is started, compressed air is supplied to the auxiliary combustion furnace and the auxiliary combustion furnace is ignited.

The object of the present invention is to provide a method for starting a turbo compressor system that can realize stable self-operation of a turbo compressor by applying combustion energy of an auxiliary combustion furnace to a turbine and causing the turbo compressor to operate on its own.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. In the figure, (1) to (11>, (13), (
14) is similar to the configuration of the conventional system described above.

(15) is a starting compressed air supply device that has a sufficient appearance to start up the turbo compressor (2) for the first time.

For example, it is possible to use an electric blower, an electric compressor, or a high-pressure tank. (16) is a startup bypass piping used when starting the system.

Of the air from Compression I (2b), the remaining amount of air, excluding the amount of air used for combustion in the auxiliary combustion furnace (9), is bypassed from the air supply pipe (5) to the system exhaust gas pipe (7). There is a control valve (17) located side by side.

Next, the operation will be explained. When starting the system, first close the switching valve (4), control valves (6), (10), open the switching valve (14) and control valve (17), and start the startup compressed air supply device (15). . Compressed air from the startup compressed air supply device (15) passes through the compressor (2b).

The air is fed into the turbine (2a) via the air supply pipe (5), the startup bypass pipe (1B), and the system exhaust gas pipe (7). At this time, the turbo compression tfi (2) is activated, and at the same time the pressure of the compressed air from the compressor (2b) increases. In this state, open the control valve (10) and open the auxiliary combustion furnace (9).
At the same time, air is introduced into the combustion chamber, and fuel is also introduced through the fuel supply pipe (11) to start combustion in the auxiliary combustion furnace (9). Auxiliary combustion furnace (
The combustion exhaust gas 9) is combined with the compressed air returning through the startup bypass piping (16) in the system exhaust gas piping (7) and is input into the turbine (2a).

As the temperature of the gas input to the turbine (2a) increases, the turbine power increases, and the discharge air pressure of the compressor (2b) also increases. When the temperature necessary for self-operation of the turbo compressor (2) is reached, open switch # (4) to stop the starting compressed air supply device (15) and close the switch valve (14). This causes the turbo compressor (2) to become self-operating. After that, by gradually opening the control valve (6) and gradually opening the control valve (17), the air passing through the startup bypass piping (16) is gradually switched to the system (1), and the compressor ( Compressed air from 2b) becomes input to the system (1).

Figure 3 shows a comparison of the changes in compressed air flow rate, pressure, and temperature during the startup process of the turbo compressor (2) with the conventional method, and Figure 3(a) shows the startup process of the conventional method. Mode Diagram FIG. 3(b) shows a startup mode diagram according to the method of the present invention, respectively. First.

In FIG. 3(a) of the conventional method, after starting the starting compressed air supply device (12) at point A, the auxiliary combustion furnace (9) is started at point 8.
) to start combustion. The accompanying turbine (21
) Due to the increase in air temperature at the inlet, the turbo compressor (
2) starts, but at the same time a sudden pressure rise occurs. Yes.

According to trial calculations, in an example where the rated compressed air pressure is 4 kg/cnrg, there is a sudden pressure rise of about 3 kg/crj at the 0 point. Therefore, as described above, it is at this point that unstable combustion and misfire tend to occur in the auxiliary combustion furnace (9). Thereafter, the starting compressed air supply device (12) is stopped at the 0 point, and the system shifts to self-operation. on the other hand.

In the method of the present invention shown in FIG. 3 (bl), the turbo compressor (2) is started and the pressure increases almost simultaneously with the start-up of the start-up compressed air supply device (15), as shown by points A and 0. Thereafter, at point 8, the auxiliary combustion furnace (9) is ignited to start combustion.Then, at point D, when the temperature has risen sufficiently, the starting compressed air supply device (15) is stopped and the operation shifts to self-powered operation. In the method of the present invention, the turbo compressor (2) is started up before the auxiliary combustion furnace (9) is ignited and combustion starts, so that the combustion state of the auxiliary combustion furnace (9), which occurs in the conventional method, is not changed. The turbo compressor (2) can be started stably without sudden pressure fluctuations and therefore without unstable combustion or misfires.

In addition, in the above embodiment, the starting compressed air supply device (15)
the inlet side system of the compressor (2b) of the turbo compressor (2),
That is, although the case where it is provided in the air supply pipe (3) has been described,
Compressed air supply bag W for startup (151 to turbo compressor (2
) may be provided in the outlet side system of the compressor (2b), that is, in the air supply pipe (5), and the same effect as in the above embodiment can be obtained.

By the way, in the above embodiment, the case where a fuel cell power generation system was targeted as the ζ system was described, but it goes without saying that it can be applied to other systems such as chemical plants, and in short, the present invention can be applied to systems that utilize turbo pressure machines. can be applied.

〔Effect of the invention〕

As explained above, when the system is started, this invention starts the startup compressed air supply device and bypasses the compressed air from the startup compressed air supply device without passing through the auxiliary combustion furnace, and inputs it into the turbine to generate the turbo compressor. After startup, compressed air is supplied to the auxiliary combustion furnace, the auxiliary combustion furnace is ignited, and the combustion energy of the auxiliary combustion furnace is given to the turbine, allowing the turbo compressor to operate on its own, thereby reducing the combustion in the auxiliary combustion furnace. Since sudden pressure fluctuations that can cause instability do not occur, stable self-operation of the t-coturbo compressor can be realized.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing a starting method of a conventional turbo compressor system, Fig. 2 is a system diagram showing a starting method of a turbo compressor system according to an embodiment of the present invention, and Fig. 3 is a system diagram showing a starting method of a turbo compressor system according to an embodiment of the present invention. FIG. 3 is a startup mode diagram showing process states; In the figure, (1) is the system, (2) is the turbo compressor, (2a) is the turbine, (2b) is the compressor, (5)
is air supply piping, (7) is system exhaust gas piping, (8) is
(9) is the auxiliary combustion furnace, (Is) is the compressed air supply device for startup, and (16) is the bypass piping for startup. Note that the same reference numerals in the two figures indicate the same or equivalent parts.

Claims (1)

[Claims] A turbo compressor consisting of a turbine driven by exhaust gas from the system and a compressor that is directly connected coaxially with this turbine and supplies the compressed air necessary for the system, and a system on the inlet side of the turbine of this turbo compressor. An auxiliary combustion furnace installed on the bypass piping that bypasses and supplies a part of the air from the compressor to supplement the insufficient power of the turbine, and a startup compressor installed in the inlet side system or the outlet side system of the compressor. In a turbo compressor system equipped with an air supply device, when the system is started, the startup compressed air supply device is started and the compressed air from the startup compressed air supply device is bypassed without passing through the auxiliary combustion furnace. After supplying compressed air to the turbine to start up the turbo compressor, compressed air is supplied to the auxiliary combustion furnace to ignite the auxiliary combustion furnace, and the combustion energy of the auxiliary combustion furnace is applied to the turbine to start the turbo compressor. A method for starting a turbo compressor system characterized by self-operation.