JP3100313B2 - Startup combustor heat shield - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat shield device for preventing a casing of a starting combustor provided in a hot gas line of a pressurized fluidized-bed boiler plant from overheating.

[0002]

FIG. 3 shows a system diagram of a complex plant equipped with a pressurized fluidized-bed boiler (hereinafter abbreviated as PFBC). In FIG. 3, 5 is PFBC, 1
Reference numeral 00 denotes a gas turbine, reference numeral 1 denotes a compressor of the gas turbine 100, and reference numeral 7 denotes a turbine. The generator 8 is rotated by the gas turbine 100.

[0003] Reference numeral 9 denotes a starting combustor for starting the gas turbine 100, and reference numeral 2 denotes a double pipe through which the compressed air from the compressor 1 and the compressed air from the gas turbine 7 are divided into and out. . 3 is a mixing chamber, 4 and 10 are air shutoff valves, 6 is a gas shutoff valve, and 11 is an air pipe.

The air discharged from the compressor 1 of the gas turbine 100 flows into the PFBC 5 through the double pipe 2, the chamber 3, and the air cutoff valve 4. In the PFBC 5, pulverized coal is burned by high-pressure air, and superheated steam generated by the combustion is sent to a steam turbine (not shown).

On the other hand, high-temperature PFBC burned by PFBC5
The exhaust gas passes through a gas shutoff valve 6 and a double pipe 2 to a turbine 7.
To rotate the compressor, and the turbine 7 drives the compressor and the generator 8. In this type of combined plant, first, the gas turbine 100 is started, and thereafter, the PFBC 5 is started by gradually opening the air cutoff valve 4 and supplying high-pressure air to the PFBC 5.

For this reason, in such a complex plant, a start-up combustor 9 for assisting start-up is installed, and at the time of start-up, the air shut-off valve 4 and the gas shut-off valve 6 are closed.
The gas turbine 100 is started by opening the air cutoff valve 10 and supplying oil or gas fuel to the starting combustor 9 to burn it. When the start of the gas turbine 100 is completed, the shutoff valves 4 and 6 are opened, the shutoff valve 10 is closed, and the operation shifts to the operation of the PFBC 5.

In the combined plant equipped with the PFBC, the casing of the starting combustor 9 shifts to the operation by the PFBC gas after the start-up is completed. Then, the casing is not cooled. For this reason, the casing is heated by the radiant heat from the PFBC gas pipe which becomes high temperature of about 870 ° C.
It will be overheated to exceed ℃.

[0008] It is an object of the present invention to improve the durability of a casing by preventing overheating of the casing due to radiant heat from the inside of a starting combustor in a PFBC plant, and to adopt a low-cost alloy steel as a casing material. It is possible to reduce the cost of the starting combustor as much as possible.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems. In a pressurized fluidized bed boiler (PFBC) plant provided with a starting combustor for starting a gas turbine, the starting combustion is performed. The device is provided with a heat shield plate having a cooling fluid passage facing the gas passage inside the casing, and providing a heat insulating layer loaded with a heat insulating material between the heat shield plate and the inner surface of the casing. The gist is a characteristic heat shield device for a starting combustor.

Therefore, according to the above means, the radiant heat due to the PFBC gas in the starting combustor is cut off by the heat shield plate, and further, the heat insulation layer interposed between the heat shield plate and the inner wall of the casing causes the heat to be provided on the casing side. The heat transfer to the heat is suppressed.

As a result, a rise in the temperature of the metal of the casing is suppressed and the thermal stress is reduced, so that it is possible to use a casing material having a lower strength and a lower price than the conventional one. In addition, since the cooling fluid passage is provided in the heat shield plate, the heat shield plate is appropriately cooled from the inside, and is not overheated by the radiant heat.

In the above-described starting combustor, preferably, the cooling fluid passage provided in the heat shield plate is formed by a plurality of grooves formed in the heat shield plate and through which cooling air flows.
The thickness of the heat insulating layer is about 50 mm, and a known heat insulating material such as asbestos or asbestos can be used as the heat insulating material.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of a heat shield device of a starting combustor of a pressurized fluidized bed boiler (PFBC) combined plant according to an embodiment of the present invention, and FIG. Each is shown.

In FIG. 2, reference numeral 9 denotes a starting combustor,
As shown in FIG. 3, the fuel is burned at the time of startup and sent to the gas turbine 7 to be started. In the starting combustor 9, reference numeral 96 denotes a gas passage through which high-temperature gas from the PFBC 5 is introduced and flows, and reference numeral 91 denotes a casing made of heat-resistant alloy steel.

In FIG. 1, reference numeral 93 denotes a heat shield made of a heat-resistant material, and its inner surface 93c is provided facing the combustion chamber 95 of the starting combustor 9. As shown in FIG. 1, the heat shield plate 93 has a thin plate 93b fixed to the inside of a base material 93a having a large number of air passage grooves 92 formed therein.
Cover the air passage 92.

Reference numeral 94 denotes a heat insulating layer interposed between the inner surface of the casing 91 and the heat shield plate 93. Thermal insulation layer 9
4 is made of a known heat insulating material (heat insulating material) such as asbestos or asbestos, and has a thickness of about 50 mm.

At the time of starting and operating the PFBC combined plant including the starting combustor 9 configured as described above, at the time of starting, referring to FIG. 3, the air shutoff valve 4 and the gas shutoff valve 6 are closed, The air shutoff valve 10 is opened, and oil or gas fuel is supplied to the starting combustor 9 to burn it in the combustion chamber 95, and this combustion gas is sent to the turbine 7 through the double pipe 2.

As a result, when the gas turbine 100 is started and the air cutoff valve 4 is gradually opened, high-pressure air from the compressor 1 is supplied to the PFBC 5, and the PFBC 5 is started.

When the operation shifts to the operation using the PFBC gas, the air shutoff valve 10 is closed, and the combustion in the starting combustor 9 is stopped, while the high temperature gas from the PFBC 5 flows through the gas passage 96 in the combustor 9. I do.

The radiant heat from this gas is radiated to the inner surface of the casing via the inner combustion chamber 95 of the casing 1.
However, inside the casing 91, the combustion chamber 95
Since the heat shield plate 93 is attached to the heat shield plate 93, radiant heat is largely reflected by the heat shield plate 93, and heat input to the inside is suppressed.

Further, since a heat insulating layer 94 is provided inside the heat shield plate 93, the heat insulating layer 94 has a heat insulating effect,
Heat transfer to the wall of the casing 91 through the heat shield plate 93 is suppressed. This suppresses the temperature rise of the casing 91 and reduces its thermal stress.

The air passage groove 9 inside the heat shield plate 93 is provided.
Cooling air flows inside 2 to cool the entire heat shield plate 93, thereby suppressing a temperature rise of the heat shield plate 93.

[0023]

According to the present invention, a heat shield plate having a cooling fluid passage is provided facing the gas chamber inside the casing of the starting combustor, and a heat insulating layer is provided between the heat shield plate and the inner surface of the casing. Since it is provided, the radiant heat to the casing in the combustor is blocked by the heat shield plate, and the heat transfer to the casing side is suppressed by the heat insulation layer.

[0024] Thereby, the temperature rise of the metal of the casing is suppressed to reduce the thermal stress, and it is possible to use a casing material having a lower strength and a lower price than the conventional one. Therefore, the manufacturing cost of the casing is greatly reduced as compared with the conventional case.

Since the heat shield plate is cooled by the cooling fluid (air) flowing in the cooling passage, the heat shield plate is not overheated.

[Brief description of the drawings]

FIG. 1 is a sectional view of a wall of a casing of a starting combustor according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of the starting combustor according to the embodiment.

FIG. 3 is a system diagram of a PFBC combined plant.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Gas turbine 5 PFBC 9 Starting combustor 91 Casing 92 Air passage groove 93 Heat shield plate 94 Heat insulation layer 95 Combustion chamber 96 Gas passage

Claims (1)

(57) [Claims] In a pressurized fluidized bed boiler (PFBC) combined plant having a starting combustor for starting a gas turbine, the starting combustor has a heat shield plate having a cooling fluid passage inside a casing. And a heat insulating layer loaded with a heat insulating material is provided between the heat shield plate and the inner surface of the casing.