JPH04259607A - Pressurized fluid floor boiler compound power generation plant - Google Patents

Abstract

PURPOSE:To reduce energy loss and cope with an overload operation by further compressing excessive compressed air at the time of boiler combustion to obtain air of higher pressure, storing it in an air storing device, and utilizing it again for boiler combustion as required. CONSTITUTION:When a pressure fluid floor boiler 1 requires a certain amount of air according to a plant load, a part of compressed air is supplied thereto from a compressor 212 through a low pressure air system 14. Excessive air is further compressed by a compressor 112, then stored in an air storing device 21 through a high pressure air system 22. When a plant requires an overload operation, the compressed air stored in the air storing device 21 is supplied again as combusting air of the pressure fluid floor boiler 1. Accordingly, energy loss can be reduced and the overload operation can be coped with.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

[Industrial Application Field] The present invention provides a steam turbine power generation facility that generates power using steam generated from a pressurized fluidized bed boiler, and a gas turbine power generation facility that generates power using combustion gas in the pressurized fluidized bed boiler. Regarding a pressure fluidized bed boiler combined power generation plant.

0002

BACKGROUND OF THE INVENTION In recent years, there has been a noticeable increase in the day-night difference in daily load and an increase in summer peak load in electricity demand, and there is an increasing demand for sharing peak load functions with thermal power generation.

On the other hand, from the idea of the best mix of power supplies,
When planning the construction of a coal-fired power plant, the issue of harmony with the global environment has become an important theme that cannot be avoided.

Under these circumstances, the pressurized fluidized bed boiler combined power generation plant has been put to practical use as a clean coal technology, and at the same time has attracted attention as a highly efficient power generation system employing a gas-steam combined cycle. Typical examples thereof will be explained below with reference to the drawings.

In FIG. 2, high-temperature steam generated in a pressurized fluidized bed boiler 1 is led to a steam turbine 3 through a main steam system 2, where it is expanded to perform work, and then discharged to a condenser 4. be done. The water condensed in the condenser 4 is heated in the stack gas cooler 5, becomes high-temperature water, and is returned to the pressurized fluidized bed boiler 1 via the water supply system 6. A generator 7 is connected to the steam turbine 3 and driven.

On the other hand, the high-pressure, high-temperature gas combusted in the pressurized fluidized bed boiler 1 is led to a gas turbine 9 through a combustion gas system 8, where it expands and performs work, and then passes through an exhaust system 10.
The gas is then sent to the stack gas cooler 5, where it further undergoes heat exchange with feed water, and then discharged from the stack 11 into the atmosphere.

[0007] In the pressurized fluidized bed boiler 1, it is possible to burn coal together with a desulfurizing agent such as dolumite, and since the combustion gas temperature is at most about 850°C, sulfur oxidation in the exhaust gas can be prevented. There are very few substances and nitrogen oxides,
No flue gas desulfurization equipment or flue gas denitrification equipment is required.

On the other hand, the gas turbine 9 drives a compressor 12 and a generator 13 that are connected to the same shaft. Compressor 12
The compressed air discharged from the pressurized fluidized bed boiler 1 is sent to the pressurized fluidized bed boiler 1 through the air supply system 14, and is used as combustion air for the fuel sent from the fuel supply system 15.

An inlet air control device 1 is installed at the inlet of the compressor 12.
6 is installed. In addition, an air supply system 17 is branched from the middle of the air supply system 14 connecting the outlet of the compressor 12 and the pressurized fluidized bed boiler 1, and this air supply system includes air for combustion during partial load. Air discharge control valve 1 to control the amount
8 is installed.

[0010] In this way, the pressurized fluidized bed boiler combined power generation plant not only eliminates the need for flue gas desulfurization equipment and flue gas denitrification equipment, but also uses a combined cycle of a gas turbine cycle and a steam turbine cycle to achieve high efficiency. It is possible to perform efficient power generation.

[0011]

[Problem to be Solved by the Invention] However, in the pressurized fluidized bed boiler combined cycle power plant of the above type, it is necessary to increase or decrease the amount of combustion air depending on the operating status of each load from the time the plant starts up to full load. Despite the fact that the gas turbine, compressor, and generator are connected to the same shaft,
It is operated at the same rotation speed as the generator, which is operated at a constant speed in synchronization with the frequency of the power grid, and the inlet air control device can only control the air amount in the high load range to prevent surging of the compressor. At load, the amount of air supplied to the pressurized fluidized bed boiler is controlled by opening the air discharge control valve to release compressed air.

For this reason, in the pressurized fluidized bed boiler combined cycle power generation plant of the above type, it is not possible to increase or decrease the amount of air appropriately according to the plant load, and the compressor does more work than necessary, especially at partial loads. This resulted in an energy loss. As a countermeasure against this problem, an air amount control system as illustrated in FIG. 3 has been put into practical use. Note that in FIG. 3, the same parts as in FIG. 2 are given the same reference numerals.

In FIG. 3, a high pressure compressor 112 and a generator 13 are connected to a high pressure gas turbine 109, and a low pressure compressor 212 is connected to a low pressure gas turbine 209. The air discharged from the low pressure compressor 212 is sent to the high pressure compressor 112, where it is further compressed, and then sent to the pressurized fluidized bed boiler 1 through the air supply system 14, where it is used as combustion air. In this case, the amount of combustion air depending on the load is controlled by the low pressure gas turbine 209 performing variable speed operation.

However, in the system shown in FIG. 3, although it is possible to increase or decrease the amount of air appropriately according to the plant load, it does not have sufficient functions to cope with overload operation. It's hard to say. [Structure of the invention]

[0015]

[Means for Solving the Problems] The pressurized fluidized bed boiler combined power generation plant of the present invention includes a steam turbine power generation facility that generates electricity using the steam generated by the pressurized fluidized bed boiler, and a combustion gas generated by the pressurized fluidized bed boiler. In a pressurized fluidized bed boiler combined power generation plant equipped with a gas turbine that generates electricity and a gas turbine power generation facility equipped with a compressor for supplying air to the pressurized fluidized bed boiler driven by the gas turbine, the compressor is compressed from a low pressure compressor. An air supply system that directly supplies part of the air as combustion air to the pressurized fluidized bed boiler, and a high-pressure compressed air system that stores the remaining air in an air storage device after further compressing it with a high-pressure compressor, The air storage device is characterized in that it has a high-pressure air supply system that supplies the stored compressed air again as combustion air to the pressurized fluidized bed boiler.

[0016]

[Operation] In the plant of the present invention configured as described above, the amount of air required for the pressurized fluidized bed boiler according to the plant load is supplied by a portion of the compressed air from the compressor through the low pressure air system. The surplus air is further compressed by a compressor and then passed through a high-pressure air system and stored in an air storage device. Furthermore, when the plant requires overload operation, the compressed air stored in the air storage device is again supplied as combustion air to the pressurized fluidized bed boiler.

[0017] Therefore, by storing surplus air from the compressor generated during partial load, it is possible to reduce energy loss, and moreover, it is possible to effectively utilize the stored energy even during overload operation.

[0018]

Embodiment Next, an embodiment of the present invention will be described with reference to FIG. Note that in FIG. 1, the same parts as in FIGS. 2 and 3 are denoted by the same reference numerals, and explanations of the overlapping parts will be omitted.

In FIG. 1, a low pressure compressor 212 and a generator 13 are connected to a high pressure gas turbine 109. The inlet air control device 16 is connected to the inlet of the low-pressure compressor 212, and the pressurized fluidized bed boiler 1 is connected to the outlet via the air supply system 14. Further, an air blowing system 17 branches off from the air supply system 14, a blowing air control valve 18 is installed in the middle thereof, and an inlet of a high pressure compressor 112 is connected to the end.

On the other hand, the combustion gas system 8 of the pressurized fluidized bed boiler 1 is connected to a high pressure gas turbine 109, and the high pressure exhaust system 110 of the high pressure gas turbine 109 is connected to the low pressure gas turbine 2.
Connected to 09. The above-mentioned high-pressure compressor 112 is connected to the low-pressure gas turbine 209, and the exhaust gas of the high-pressure compressor 112 is connected to the air storage equipment 21 through the high-pressure compressed air system 19 and the air storage equipment inlet valve 20 installed in the middle. has been done. The air storage equipment 21 also includes a high-pressure air supply system 22 and an air supply control valve 2 installed in the middle of the system.
A pressurized fluidized bed boiler 1 is connected via 3.

In the plant of the present invention having such a configuration, the high-pressure gas turbine 109, the low-pressure compressor 212, and the generator 13 are operated at a constant rotation speed during operation other than when starting up.

When the pressurized fluidized bed boiler combined cycle power plant is operated at a relatively high load, the amount of air in the low pressure compressor 212 is controlled by the inlet air control device 16, and the air sucked into the low pressure compressor 212 is controlled by the inlet air control device 16. After being compressed, e.g. 1
Air supply system 14 at a pressure of about 4 to 20 kg/cm2
is discharged. The air that has passed through the air supply system 14 is sent to the pressurized fluidized bed boiler 1 and used as combustion air for the fuel sent from the fuel supply system 15, and its exhaust gas is used to perform work in the high-pressure gas turbine 109.

At partial load, the amount of combustion air sent to the pressurized fluidized bed boiler 1 is reduced by opening the blow-off control valve 18 installed in the blow-off system 17, and at the same time the amount of combustion air sent to the pressurized fluidized bed boiler 1 is reduced. The fuel consumption is also reduced to allow combustion to occur in accordance with the required load. Exhaust gas from the pressurized fluidized bed boiler 1 is guided to a high pressure gas turbine 109 to perform work. The exhaust gas that has worked in the high pressure gas turbine 109 works again in the low pressure gas turbine 209.

On the other hand, the air controlled by the blow-off control valve 18 is sent to a high-pressure compressor 112 driven by a low-pressure gas turbine 209, where the air is further compressed to about 30 kg/cm, for example.
Compressed to a pressure of 2 or more. This high-pressure compressed air is sent from the high-pressure compressed air system 19 via the air storage facility inlet valve 20 to the air storage facility 21 and stored there as high-pressure air.

During overload operation, the high-pressure air stored in the air storage facility 21 passes through the high-pressure air supply system 22 and is controlled by the air supply control valve 23 in the middle of the flow to a level of several kg/cm2 from inside the pressurized fluidized bed boiler 1. The air is controlled to a high pressure and sent to the pressurized fluidized bed boiler 1, where it is used as combustion air.

[0026]

As described above, according to the present invention, surplus compressed air for combustion in a pressurized fluidized bed boiler during partial load is compressed into higher pressure air by a high pressure compressor, and then By storing it in an air storage facility and reusing it for combustion in a pressurized fluidized bed boiler when necessary, energy loss can be reduced and it is also possible to cope with overload operation.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a pressurized fluidized bed boiler combined cycle power plant according to the present invention.

FIG. 2 is a schematic diagram of a conventional pressurized fluidized bed boiler combined power generation plant.

FIG. 3 is a schematic diagram of a conventional pressurized fluidized bed boiler combined cycle power plant.

[Explanation of symbols]

1... Pressurized fluidized bed boiler 3...Steam turbine 4...Condenser 5...Stack gas cooler 8... Combustion gas system 9...Gas turbine 11...Stack 12...Compressor 18...Air discharge control valve 20...Air storage equipment inlet valve 21...Air storage equipment 22...High pressure air supply system 23...Air supply control valve 109...High pressure gas turbine 112...High pressure compressor 209...Low pressure gas turbine 212...Low pressure compressor

Claims (1)

[Claims] Claim 1: A steam turbine power generation facility that generates electricity using steam generated by a pressurized fluidized bed boiler, a gas turbine that generates electricity using combustion gas in the pressurized fluidized bed boiler, and a pressurized fluidized bed boiler that is driven by the gas turbine. In a pressurized fluidized bed boiler combined power generation plant equipped with a gas turbine power generation facility equipped with an air supply compressor, a part of the compressed air from the low pressure compressor is directly used as combustion air for the pressurized fluidized bed boiler. and a high-pressure compressed air system that further compresses the remaining air with a high-pressure compressor and stores it in an air storage device, and the air storage device returns the stored compressed air to the pressurized fluidized bed. A pressurized fluidized bed boiler combined power generation plant characterized by having a high pressure air supply system for supplying combustion air to the boiler.