JP2000054855A - External heating type gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an external heating type gas turbine in which the exhaust gas of a small gasification combustion type incinerator can be efficiently utilized to heat gas turbine compressed air. SOLUTION: This external heating type gas turbine is provided with an open cycle gas turbine 7 equipped with a gas turbine compressor 5, an internal combustor 8 and a regenerator 9, a refuse batch throwing gasification combustion type incinerator 1 and an external heater 2 arranged in the exhaust gas passage of the incinerator 1, and is equipped with a compressed air passage by which the compressed air from the compressor 5 is passed through the external heater 2 through a regenerator bypass valve 12 connected to a regenerator bypass circuit and led to the gas turbine 7 via the internal combustor 8. The amount of compressed air to be passed through the regenerator 9 can be increased, and the temperature of the compressed air to be entered in the external heater 2 is raised by providing at the time of starting/stopping of the incinerator 1 a control device 15 which detects the outlet temperature air of the external heater 2 by a device 13 and controls by the regenerator bypass valve 12 the amount of the compressed air 4' to be passed through the regenerator 9 so as to retain the outlet temperature of the heater 2 to a high temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an externally heated gas turbine, and more particularly, to an externally heated gas turbine for power generation for exchanging heat between hot combustion gas and air in a small incinerator.

[0002]

2. Description of the Related Art Externally heated gas turbines have been developed for the purpose of heating compressor outlet air with the combustion exhaust gas of solid fuel such as coal or wood to reduce the amount of fuel used in an internal combustor. As an example of an externally heated gas turbine, it has been demonstrated that a 500 kW gas turbine can be operated by heating air to 1000 ° C. with a pulverized coal burner combustion gas at 1200 ° C. This project is a subsidized project of the US Department of Energy and aims to increase the efficiency of existing coal-fired boiler / steam turbine systems of 100,000 kW or less. The external heater for the gas turbine in this project uses a ceramic shell-and-tube heat exchanger.

[0003] On the other hand, a small gas turbine generator has been developed for a hybrid vehicle using both electricity and fuel, and a gas turbine generator having an output of about 50 kW can be commercialized. Such a small gas turbine is called a micro gas turbine, and is expected to be a cogeneration prime mover having a number of parts that is one tenth or less compared to a gas engine and having much lower maintenance costs. The micro gas turbine has a pressure ratio of about 4,
Since the turbine inlet temperature is 1000 ° C., if an inexpensive external heater can be obtained, a heat source of biomass such as wood chips can be effectively used.

[0004] In addition, a small gasification combustion type incinerator which is separated so that vinyl chloride which causes dioxin is not mixed is kept at a combustion gas temperature of 800 ° C or more, and smoke and
It is a small incinerator that generates very little soot and dioxin, and can be equipped with an external fuel burner that keeps the exhaust gas temperature high even when the incinerator starts and stops. Also,
Exhaust heat recovery of an incinerator with a garbage incineration capacity of less than 200 kg / h generally involves recovery of hot water, and there is no method of inexpensively converting it into electric power. Small incinerators employ a batch type in which refuse is batch-injected, and boiler / steam turbine types used in large continuous incinerators were not implemented in terms of power generation efficiency and availability. .

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned prior art, the present invention provides an externally heated gas turbine capable of efficiently using the exhaust gas of a small gasification combustion type incinerator for heating the compressed air of a gas turbine. The task is to provide.

[0006]

In order to solve the above-mentioned problems, the present invention provides an open-cycle gas turbine having a gas turbine compressor, an internal combustor, and a regenerator, and a refuse lump-type gasification combustion type incinerator. And an external heater that exchanges heat between the exhaust gas of the incinerator and the compressed air from the gas turbine compressor, and the compressed air from the compressor is connected to a regenerator bypass circuit via a regenerator bypass valve. In an externally heated gas turbine having a compressed air path that passes through the external heater and passes through an internal combustor to a gas turbine, an outlet temperature air of the external heater is detected and the outlet temperature of the heater is increased. An externally heated gas turbine is provided with a control device for controlling the amount of compressed air passing through the regenerator by a regenerator bypass valve so as to maintain the same.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a small incinerator, a batch system in which refuse is supplied at a time is generally used, and the amount of gas from a gasification chamber is not constant from start to stop. The secondary combustion chamber of the small gasification combustion type incinerator is charged with secondary air and clean fuel such as kerosene, complete combustion, and the combustion temperature is maintained at 800 ° C or higher, but the amount of exhaust gas stops from startup. Until it fluctuates. On the other hand, when the gas turbine generator is a single-shaft gas turbine in which the compressor, turbine, and generator are on the same shaft, the shaft rotation speed is the same as the synchronous rotation speed of the AC generator, and the compressor outlet flow rate and temperature are It is kept constant regardless of the amount of power generated. When the compressor output air is heated by increasing the fuel input amount in the combustor, the power generation output increases the turbine inlet temperature and increases the power generation amount. The external heater can recover the heat of the exhaust gas from the small gasification combustion type incinerator and reduce the amount of clean fuel such as kerosene used in the combustor room. Assuming that the amount of power generation is constant, the higher the return air temperature from the external heater, the more the amount of clean fuel used can be reduced.

[0008] Heat transfer area of the external heater, compressor outlet flow rate,
Given the compressor outlet temperature and the incinerator exhaust gas temperature, the heating air temperature is determined from the incinerator exhaust gas amount. Given the design exhaust gas amount of the incinerator, the exhaust gas temperature, the gas turbine compressed air flow rate, and the gas turbine compressor outlet temperature, the heater allowable outlet temperature is determined from the heat exchange material allowable temperature of the heater. Assuming that the heater allowable outlet temperature is determined with the gas turbine regenerator fully bypassed, when the incinerator starts and stops, the amount of combustion exhaust gas is small, and the heater outlet temperature falls below the design value, If the gas turbine power generation is constant, the consumption of additional fuel such as kerosene increases. The present invention directs a portion of the compressor outlet air to a regenerator,
By increasing the heater inlet temperature, the heater outlet air temperature is kept close to the allowable limit of the heater tube material even when the incinerator exhaust gas amount is smaller than the rated value.

A bypass valve of a regenerator of a micro gas turbine without an external heater is used to control the amount of hot water of a hot water heat exchanger installed at the outlet of the regenerator. The amount of hot water is controlled by increasing the gas turbine exhaust gas temperature at the outlet of the regenerator.
In the gas turbine system of the present invention with an external heater, a regenerator bypass valve is used as a means to increase the heater inlet temperature. Since the control of the hot water is given priority to the control of the outlet temperature of the heater, when the temperature of the hot water is too high, heat is radiated by the heat radiating circuit. The hot water radiating circuit is a device necessary for protecting the tubes of the hot water heat exchanger, and has a function of releasing heat when there is no demand for hot water, similarly to a jacket cooling device of a diesel engine or a gas engine.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating an example of a power generation device using the externally heated gas turbine of the present invention. In FIG. 1, 1 is a lump-type gasification combustion incinerator, 2 is a high-temperature heater, 3 is an exhaust gas from an incinerator, 4 is air for a gas turbine, 4 'is bypass circuit air, 5' is a compressor, 6 is a generator, 7 is a turbine, 8 is an internal combustor, 9 is a regenerator, 10
Denotes a hot water heat exchanger, 11 denotes a gas turbine exhaust gas, and 12 denotes a regenerator bypass valve. In the gas turbine power generation shown in FIG.
The compressor 5, the gas turbine 7, and the generator 6 are connected to the same shaft.
It is compressed and heated to a temperature of 230 ° C. at 4 MPa · abs. When the incinerator 1 is in rated operation, the regenerator bypass valve 1
2 guides the entire amount of compressed air 4 to the high-temperature heater 2. The incinerator exhaust gas temperature of the high temperature heater 2 is cooled from 1200 ° C. to 750 ° C. The compressed air 4 is heated from 230 ° C. to 750 ° C.

[0011] The tube of the high temperature heater has a material allowable temperature of 1
A heat-resistant steel having a chromium content of about 2,000 ° C. or less and about 25% is used. Since the heater outlet temperature is set as low as 750 ° C., the heat transfer area can be reduced, and an inexpensive metal tube can be used instead of expensive ceramics.
In addition, since it is a combustion gas of separated garbage that does not contain vinyl chloride, there is no danger of high temperature corrosion of metal tubes due to hydrogen chloride.
The inlet temperature of the gas entering the gas turbine is 1000 ° C., the external fuel 16 (such as kerosene) is injected into the internal combustor 8 and heated from 750 ° C. to 1000 ° C. at the outlet air of the heater. Then, the compressor 5 and the generator 6 are driven. Compared to a simple open cycle gas turbine without the high temperature heater 2, the fuel consumption of the internal combustor 8 is reduced by 68% because it is heated externally from 230 ° C. to 750 ° C.

When the power generation efficiency of the above simple open cycle gas turbine is set to 15% and the ratio of the heat input amount of the external fuel excluding the heat input to the external heater to the power generation amount is defined as the external fuel power generation efficiency, The power generation efficiency using the heater becomes 47%. Large state-of-the-art simple open cycle gas turbines,
Since the power generation efficiency of the diesel engine and the fuel cell is about 40%, the micro gas turbine of the present invention has effectively utilized the unused energy of the waste. The gas turbine regenerator 9 is used to heat the compressor outlet air when the incinerator exhaust gas volume decreases when the incinerator is stopped. When the amount of exhaust gas from the incinerator decreases, the air at the heater outlet becomes 7
To reduce the temperature to 50 ° C. or less, the regenerator bypass valve 12 is moved to the regenerator side, and a part of the compressor outlet air 4 ′ is removed from the regenerator 9.
To increase the air inlet temperature of the heater 2. A temperature detector 13 for detecting the air temperature before entering the internal combustor 8 is installed, and the output of the controller 14 that sets the temperature set value to 750 ° C. is used as the input of the driving device 15 of the regenerator bypass valve 12. Thereby, the heater outlet air can be kept constant at 750 ° C. regardless of the operating state of the incinerator.

When the regenerator bypass valve is led to the full regenerator, the temperature of the heater air inlet rises to 590 ° C., and when the incinerator starts and stops, even if the heat input of the heater 2 decreases, the external fuel 1
6 can be prevented from increasing. A hot water heat exchanger 10 for exchanging heat between the gas turbine exhaust gas 11 and the hot water 17 is installed at the outlet of the regenerator 9 to recover hot water, and cool water is obtained by driving a hot water drive absorption refrigerator using the hot water. be able to. In diesel and gas engine cogeneration, making cylinder jacket cooling water high-temperature water is not usually performed because it has a bad effect on engine cooling, but hot water heat exchangers in gas turbines can remove high-temperature water. It is possible. When the temperature of taking out hot water is raised from 83 ° C. to 110 ° C., the coefficient of performance of the hot water absorption refrigerator is improved by about 7%.

[0014]

According to the present invention, in the case where a lump-input gasification combustion incinerator is used as an external heating source of an externally heated gas turbine, a gas turbine regenerator and a regenerator can be used in response to fluctuations in exhaust gas from the incinerator. By controlling the temperature of the air introduced into the external heater by the heater bypass valve, the air temperature at the outlet of the external heater can be kept constant, and the external fuel consumption of the gas turbine combustor can be maintained even when the incinerator starts and stops. Can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of a power generation device using an externally heated gas turbine of the present invention.

[Explanation of Signs] 1: Lump input type gasification combustion incinerator, 2: High temperature air heater, 3: Incinerator exhaust gas, 4: Air for gas turbine,
4 ': bypass circuit air, 5: compressor, 6: generator,
7: gas turbine, 8: internal combustor, 9: regenerator, 1
0: hot water heat exchanger, 11: gas turbine exhaust gas, 12:
Regenerator bypass valve, 13: temperature detector, 14: temperature controller, 15: regenerator bypass valve drive unit, 16: external fuel,
17: warm water,

Claims (1)

[Claims] An open cycle gas turbine having a gas turbine compressor, an internal combustor and a regenerator, a lump-type gasification combustion incinerator, exhaust gas from the incinerator, and compressed air from the gas turbine compressor. An external heater for exchanging heat with compressed gas from the compressor, through a regenerator bypass valve connected to a regenerator bypass circuit, through the external heater, through an internal combustor to a gas turbine. An externally heated gas turbine having a compressed air path leading to the regenerator bypass valve by detecting the temperature of the outlet air of the external heater and controlling the amount of compressed air to be passed through the regenerator so as to keep the outlet temperature of the heater high. An externally heated gas turbine, comprising: a control device that controls the temperature of the gas turbine.