JP3074448B2 - Combined power generation system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combined power generation system comprising a gas turbine and a pressurized fluidized bed combustor.

[0002]

2. Description of the Related Art A conventional pressurized fluidized bed power generation system is shown in FIG.
As described above, the system is composed of a gas turbine, a pressurized fluidized bed boiler, and an ultra high temperature steam turbine, and the pressurized fluidized bed boiler plays a role of a contact point between the gas turbine and the ultra high temperature steam turbine.

[0003]

Accordingly, the pressurized fluidized bed boiler requires the energy required for both the gas turbine and the ultra high temperature steam turbine, and is a severe boiler. In particular, the furnace temperature of a pressurized fluidized-bed boiler needs to be lower (800 to 900 ° C.) than that of a conventional boiler for desulfurization and denitration.

Further, since the pressurized fluidized-bed boiler has a heat transfer tube for generating steam to be supplied to the steam turbine, its wear is remarkable, and there has been a problem in reliability. Further, the pressure vessel containing the pressurized fluidized-bed boiler is large, which has contributed to an increase in cost. By incorporating heat transfer tubes inside a pressurized fluidized-bed boiler, the conditions for the generated steam can be increased and the power generation efficiency of the steam turbine can be increased, but on the other hand, the pressure vessel becomes larger due to the installation space for the heat transfer tubes. Become. An object of the present invention is to provide a combined power generation system that can solve such a conventional disadvantage.

[0005]

That is, a combined power generation system of the present invention is a combined power generation system that generates power using a gas turbine and a steam turbine having two low-pressure and high-pressure turbines and a compressor. Turbine exhaust gas into the fluidized bed of a pressurized fluidized bed combustor
Introduce coal and limestone into pressurized fluidized bed combustor
And desulfurization at the same time as combustion.
From the flow rate of turbine exhaust gas introduced into the fluidized bed and from the compressor
The flow rate of the bled discharge air and the pressure inside the pressurized fluidized bed combustor
The pressurized fluidized bed combustor is
Discharged air extracted from the compressor inside the built-in pressure vessel
And exhaust gas discharged from a pressurized fluidized bed combustor through a cyclone is introduced into a waste heat boiler through a low pressure turbine having a low expansion ratio.

[0006]

The above pressurized fluidized bed combustor is a conventional pressurized fluidized bed combustor.
Unlike boilers, there are no heat transfer tubes for steam turbines.
There is no problem such as wear of the heat transfer tube due to the flow of the moving bed.
Also, bleed air from the compressor is small amount quantitatively because air for pressurizing the pressure vessel, there is no effect on the high 圧Ta turbine.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 10 denotes a normal fuel-fired gas turbine. For example, a gas fuel f such as natural gas is burned in a combustor 14 while being mixed with a discharge air a ′ compressed by a compressor 11. , In the high-pressure gas turbine 14.

The exhaust gas g is guided to a fluidized bed 17 of a pressurized fluidized bed combustor 16. The compressed fluidized-bed combustor 16 together with the discharge air a ″ extracted from the compressor 11
The respective flow balances are maintained according to the internal pressure. The pressure of the discharge air a ″ is set slightly higher than the exhaust gas g of the high-pressure gas turbine 14.

The oxygen concentration in the exhaust gas g of the high-pressure gas turbine 14 is relatively high.
6, it is possible to burn the coal c. However, since the combustion stability and the pressure vessel 18 of the pressurized fluidized bed combustor 16 are filled with the discharge air a ″, the bleed air of the compressor 11 is balanced. Coal c as a fuel and coal stone d for desulfurization are charged into the pressurized fluidized bed combustor 16, and are desulfurized simultaneously with combustion in the pressurized fluidized bed combustor 16. And ash are discharged out of the system.

The combustion gas g 'discharged from the pressurized fluidized-bed combustor 16 passes through the cyclone 19 and the filter 20, and then is guided to the low-pressure gas turbine 15 to rotate the generator 13 and generate power. It has become. The temperature of the exhaust gas g ″ of the low-pressure gas turbine 15 is higher than the normal exhaust gas temperature because the turbine expansion ratio is designed to be low.
Therefore, when recovering steam in the waste heat boiler 21 located downstream of the low-pressure gas turbine 15, the set conditions can be increased, and the power generation efficiency of a steam turbine (not shown) can be increased.

The heat transfer tube of the waste heat boiler 21 is a gas with good conditions, and has no wear and no sulfur content in the gas, so that low-temperature corrosion and the like can be avoided. FIG. 2 is a state diagram of the combined cycle of the present invention.
Nos. 3 to 3 are pressurization processes using ordinary fuel. 3-4
Output of high pressure gas turbine. Nos. 4 to 5 are heating processes by the pressurized fluidized bed combustor. Reference numerals 5 and 6 denote outputs generated by the low-pressure gas turbine.

The amount of work of the conventional method is 1 to 1 'to 4 to 5
The amount of work of the present invention corresponds to a portion surrounded by
It corresponds to a portion surrounded by 1-2 to 3-4 to 5-6. Therefore, it can be seen from FIG. 2 that the method of the present invention has a larger workload than the conventional method.

[0013]

As described above, according to the present invention, the fluidized bed in the pressurized fluidized bed combustor is fluidized by the exhaust gas of the high pressure gas turbine and the air extracted from the compressor. Since the combustion gas discharged from the vessel is introduced into the low-pressure gas turbine to generate power, and the waste heat is recovered from the exhaust gas of the low-pressure gas turbine, an unprecedented superior effect is achieved.

That is, the adoption of a high-efficiency gas turbine has reduced the amount of petroleum-based fuel and enabled clean power generation. The equipment became compact and reliable power generation became possible. Despite the use of some coal as fuel, it has become possible to construct a conventional high-level power source.

[Brief description of the drawings]

FIG. 1 is a system diagram of a combined cycle power generation system according to the present invention.

FIG. 2 is a cycle state diagram of the present invention.

FIG. 3 is a system diagram of a conventional combined cycle system.

[Explanation of symbols]

a "Air extracted from the compressor g Exhaust gas from the high pressure gas turbine g 'Combustion gas exhausted from the pressurized fluidized bed combustor g" Exhaust gas from the low pressure gas turbine 16 Pressurized fluidized bed combustor 17 Fluidized bed 15 Low pressure gas turbine

Claims (1)

(57) [Claims] 1. A combined power generation system for generating electric power by a gas turbine and a steam turbine having two turbines and a compressor at a low pressure and a high pressure, wherein a turbine exhaust gas discharged from a high pressure turbine is fluidized by a fluidized bed of a pressurized fluidized bed combustor. Introduced in
And adding coal and limestone to the pressurized fluidized bed combustor
Desulfurization at the same time as combustion
Flow rate of turbine exhaust gas introduced into the floor and extraction from compressor
The flow rate of the discharged air and the pressure in the pressurized fluidized bed combustor.
Built-in pressurized fluidized bed combustor balanced according to each
Pressure vessel filled with discharge air extracted from the compressor.
Plus further combined power generation system characterized in that to introduce the pressurized fluidized bed low pressure turbine menstrual and waste heat boiler of the expansion ratio of the combustion exhaust gas discharged through the cyclone from the combustor.