JPH08135409A - Refuse incinerating gas turbine combined power generation system - Google Patents

Abstract

PURPOSE: To improve plant efficiency by way of preventing high temperature corrosion in a refuse incinerating boiler by heating a combustor by way of leading water or steam heated by a refuse incinerator to the combustor attached to a gas turbine in a combined power generation system including the refuse incinerator and the gas turbine. CONSTITUTION: Gas generated in a refuse incinerator 3 is discharged from a chimney 6 through an exhaust gas processing device 5 after it is heat- exchanged by a refuse incinerating boiler 4. In the meantime, most of feedwater 18 boosted by a high pressure feedwater pump 17 becomes superheated steam 19 as it is led to a superheater 11 after it is heated by the refuse incinerating boiler 4 until it becomes saturated steam 25, and it is introduced to a steam turbine 20. At this time, a part of the feedwater 18 is heat-exchanged by an exhaust heat recovery boiler 15 and made to be the superheated steam 19, led to the steam turbine 20 with the superheated steam from the superheater 11 and it drives a power generator 13. Thereafter, the steam is condensed by a condenser 16. Additionally, the saturated steam 25 is introduced to the superheater 11 and made to be the superheated steam 19.

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 utilizing steam generated in a refuse incinerator and a gas turbine.

[0002]

2. Description of the Related Art Many local governments make effective use of waste incineration heat to generate electricity. At that time, chlorine is generated in the combustion gas because a large amount of chlorine is generated from vinyl chloride, which is a kind of plastic in the garbage that becomes fuel, and salt contained in the garbage. When the chlorine gas reaches a high temperature, the corrosion of the boiler tube progresses, which is a problem when the waste incineration heat is used. Therefore, in power generation using waste incineration heat, the temperature of the steam that can be taken out by the boiler must be 300 ° C or lower, which is lower than the steam temperature of 480 ° C used in ordinary thermal power plants, and therefore the power generation efficiency is low. There was a problem.

Therefore, as a method for improving power generation efficiency,
It has been proposed to install a superheater independent of the refuse incinerator in order to raise the temperature of the steam with a chlorine-free fuel. For example, as a heat source for a superheater, JP-A-5-59905
Japanese Patent Laid-Open No. 59-21 / 1999, a method of utilizing exhaust gas from a gas turbine attached to a refuse incinerator as described in Japanese Patent Publication No. 59-21
There is a method in which a heating furnace for burning a chlorine-free fuel described in Japanese Patent No. 5503 is installed and combustion gas generated therein is used.

[0004]

The method described in Japanese Patent Laid-Open No. 5-59905 is a combination of a gas turbine and a steam turbine, and a power plant can be expected to have a significant improvement in efficiency. However, since the amount of steam generated in a waste incinerator, whose heat generation amount and treatment amount fluctuate greatly, also changes the operating state of the superheater installed in the exhaust heat recovery boiler of the gas turbine, resulting in stable exhaust heat recovery. Boiler performance cannot be obtained. The problem with this method is that in order to control according to fluctuations, it is necessary to install an auxiliary combustion burner, which does not exist in conventional combined cycle power plants, in the exhaust heat recovery boiler. Further, in the method described in JP-A-59-215503, the amount of fuel burned in the heating furnace is adjusted to superheated steam according to the fluctuation of the heat generation amount of the refuse incineration boiler, so that it is easy to control but the efficiency is low. Does not improve as much as combined power generation.

It is an object of the present invention to provide a system which is efficient and can supply stable steam to a steam turbine.

[0006]

As a measure for solving the conventional problems, the present invention provides a superheater in the combustor of a gas turbine to generate heat in the combustor in response to fluctuations in the refuse incinerator. Change the amount.

[0007]

In the present invention, since the superheater is provided in the combustor of the gas turbine, the high temperature corrosion in the refuse incinerator is prevented,
High-temperature steam, which could not be obtained by conventional waste incineration plants, can be recovered, and high efficiency can be achieved. Also,
Stable superheated steam can be supplied to the steam turbine by controlling the amount of fuel and compressed air supplied to the combustor according to the load fluctuation of the refuse incineration boiler. Further, since the exhaust heat of the gas turbine is stable as before, an exhaust heat recovery boiler having the same specifications as the conventional gas turbine plant can be installed.

[0008]

FIG. 1 shows a system diagram of a system in which a gas turbine and a refuse incinerator are combined as one embodiment of the present invention.
In the gas turbine system, the air 7 taken in from the air intake system is compressed by the air compressor 8 and the combustor 1 together with the chlorine-free fuel 9 supplied from the fuel supply system.
Burns at 0. At that time, heat is exchanged with the superheater 11 installed inside the combustor 10, and the temperature is reduced to the preset temperature at the inlet of the gas turbine 12. The combustion gas 14 that has worked in the gas turbine 12 and caused the generator 13 to generate electric power is heat-exchanged in the exhaust heat recovery boiler 15 and then discharged from the chimney 6 into the atmosphere. Next, the refuse 1 supplied from the refuse supply system is burned in the refuse incinerator 3 together with the combustion air 2. The gas generated by the combustion is heat-exchanged in the refuse incineration boiler 4, then is guided to the chimney 6 through the exhaust gas treatment device 5, and is discharged to the atmosphere. On the other hand, most of the feed water 18 pressurized from the condenser 16 by the high-pressure feed pump 17 is heated in the refuse incineration boiler 4 until it becomes saturated steam 25, and then is guided to the superheater 11 to become superheated steam 19. And is introduced into the steam turbine 20. Part of the feed water 18 pressurized by the high-pressure feed water pump 17 exchanges heat with the exhaust heat recovery boiler 15 to become superheated steam 19, which is guided to the steam turbine 20 together with the superheated steam generated by the superheater in the combustor. . The work by the steam turbine 20 is converted into electric power by the generator 13, and the steam that has finished the work is condensed by the condenser 16.

The flow rates of the air 7 and the fuel 9 are controlled by a flow rate control device 22 which senses the value of a steam flow meter 21 installed between the refuse incineration boiler 4 and the superheater 11.

As an example of the shape of the superheater, a case where the superheater is installed on the combustor wall is shown in FIG. The fuel 9 and the compressed air 7 introduced to the combustor 10 are combusted as a stabilized flame 27 by the action of the flame stabilizer 26. AA 'in FIG.
An enlarged cross section is shown in FIG. Since the inside of the combustor has a high pressure of about 1 MPa, the outer wall 30 is to withstand the pressure,
The furnace wall 28 present between the steam and flame is thinned to provide good heat transfer to the steam. Generally, since heat is transferred from the flame 27 to the furnace wall 28 by radiation, a high heat flux can be obtained, so that it is not necessary to provide fins or the like on the inner surface. On the other hand, since the heat transfer between the steam and the furnace wall is smaller than the radiant heat transfer, the fins 29 are provided on the furnace wall to increase the effective heat transfer area to promote the heat transfer. The fins 29 also play a role of a strength member that supports the pressure of steam.

An example of actual operation of the system shown in FIG. 1 will be described below. Assuming that the amount of waste treated per day is 1,000 tons and the average calorific value of waste is 2000 kcal / kg, the steam turbine inlet pressure is 3 MPa, the temperature is 350 ° C., the gas turbine inlet pressure is 1 MPa, and the temperature is 1100 ° C. The amount is 120 t / h by the waste incinerator and superheater, and 50 t / h by the exhaust heat recovery boiler, and the plant efficiency is 35%. At that time, since the steam temperature at the outlet of the refuse incineration boiler is about 240 ° C, the problem of high temperature corrosion due to chlorine can be avoided. When LNG is used as the fuel supplied to the combustor of the gas turbine, the fuel flow rate is 2.0 kg / s on average.
, About 170t / day.

As another embodiment of the present invention, depending on the temperature of the combustion gas of the gas turbine 12 and the selection conditions of the specifications of the steam turbine 20, the steam turbine 20 is of a double pressure type as shown in FIG. It is also conceivable that the feed water of the above is led to the exhaust heat recovery boiler 15 and given to the steam turbine 20 as the low pressure steam 24.

[0013]

According to the present invention, plant efficiency can be remarkably improved without causing high temperature corrosion in the refuse incineration boiler, and large-scale power generation utilizing the refuse incineration heat can be realized.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an example of the shape of a superheater.

FIG. 3 is an explanatory diagram of an example of the shape of a superheater.

FIG. 4 is a system diagram showing another embodiment of the present invention.

[Explanation of symbols]

 3 ... refuse incinerator, 10 ... combustor, 12 ... gas turbine.

Claims (1)

[Claims] 1. In a combined power generation system including a refuse incinerator and a gas turbine, water or steam heated in the refuse incinerator is guided to a combustor attached to the gas turbine,
A waste incineration gas turbine combined cycle power generation system characterized by heating the combustor.