WO2011065605A1

WO2011065605A1 - Method and system for optimally operating a power plant boiler

Info

Publication number: WO2011065605A1
Application number: PCT/KR2009/007045
Authority: WO
Inventors: 윤기봉
Original assignee: 중앙대학교 산학협력단
Priority date: 2009-11-25
Filing date: 2009-11-27
Publication date: 2011-06-03
Also published as: KR20110057923A; KR101074358B1

Abstract

The present invention relates to a method for optimally operating a power plant boiler and, in particular, to a method for providing a uniform temperature distribution within a power plant boiler, said method comprising the steps of: receiving input of actual cumulative thermal damage information about a boiler tube, via a sensor installed on the boiler tube or near the boiler tube; receiving input of virtual cumulative thermal damage information about the boiler tube, via a computer simulation; comparing the actual thermal damage information to the virtual thermal damage information to correct the computer simulation; and setting boiler operating conditions using the corrected computer simulation so that the temperature within the boiler has uniform distribution.

Description

Optimal operating method of power plant boiler and its system

The present invention relates to a method of operating a power plant boiler and a system thereof.

In general, a power plant is a device for converting fuel energy into electrical energy, and is generally composed of a boiler and a turbine. A boiler is a device that generates steam by converting water into steam, and steam generated by the boiler generates electric energy by turning a turbine.

1 illustrates a conventional power plant, referring to FIG. 1, coal stored in a coal bunker 1 is supplied to a crusher 2 and crushed finely. The crushed coal fuel is spark ignited in the tilting burner 3, and the flame of the tilting burner 3 is injected into the combustion chamber C inside the boiler 10.

The boiler tube is a tube installed inside the boiler 10 and is heated by the combustion gas of the combustion chamber C. The boiler tube includes a preheater 4, a pelletizer 5, a superheater 6, and a reheater 7.

The preheater 4 which is heated by the combustion gas is installed below the boiler 10. The preheater 4 is a device for preheating the water supply flowing into the boiler 10.

The water preheated in the preheater 4 flows into the coal mill 5. The cinder 5 is a device for heating by using the remaining heat of the combustion gas discharged from the boiler 10 and is located between the rear passage 15 of the boiler 10 and the air preheater 8.

The coke machine 5 is connected to the superheater 6. The superheater 6 generates heated steam by the hot combustion gas inside the boiler 10.

The superheated steam generated in the superheater 6 turns the high pressure turbine 20, and the steam which loses a predetermined amount of heat while turning the high pressure turbine 20 flows into the reheater 7 inside the boiler 10.

The reheater 7 is a device for reheating the steam passing through the high pressure turbine 20. The steam reheated in the reheater 7 flows into the medium pressure turbine 25 and turns the medium pressure turbine 25. The steam which turned the medium pressure turbine 25 exits the medium pressure turbine 25, flows into the low pressure turbine 27, and turns the low pressure turbine 27. As shown in FIG.

The generator 30 is connected to the low pressure turbine 27 and generates electric energy by the rotation of the low pressure turbine 27.

On the other hand, the combustion gas passing through the back passage 15 of the boiler 10 is dust is removed from the dust collector (40).

In addition, air is supplied from the air supply 11, and is supplied to the combustion chamber C through the air duct 12.

The air preheater 8 is located between the air supply 11 and the air duct 12 and is also located between the rear passage 15 and the dust collector 40 of the boiler 10.

Thus, the tube of the conventional boiler is heated by the hot combustion gas of the combustion chamber (C), the heated steam turns the turbine to generate electrical energy.

On the other hand, the boiler tube is formed of a plurality of steel pipes, as shown in Figure 2, due to the high temperature environment inside the boiler is often the case that some of the steel pipes are broken during operation. During operation, if the steel pipe breaks, the entire system of the power plant is shut down, causing huge losses.

In order to solve this problem, a method of determining an abnormality by measuring a real-time temperature of a conventional boiler tube has been disclosed. However, such a conventional technique uses a thermocouple or a thermal radiation thermometer, and the thermocouple method requires an electrical connection to a sensor and is limited in use at high temperature conditions such as a boiler. In addition, the thermal radiation thermometer does not need an electrical connection, but there is a limit that it is difficult to accurately measure the temperature because the radiation rate of the tube is not 1 and is influenced by the material, surface state, etc. of the tube.

Therefore, according to the prior art, it is difficult to determine the exact cause of the high temperature breakage because the temperature distribution inside the power plant boiler is not known, and there is a limit to changing the operating conditions to have a uniform temperature distribution inside the boiler.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to set an optimum operating condition such that the temperature distribution inside the power plant boiler has a uniform distribution.

A method of operating a power plant boiler according to the present invention for achieving the above object includes: receiving accumulated measured high temperature damage information of a boiler tube through a boiler tube or a sensor installed near the boiler tube; Receiving accumulated virtual high temperature damage information of the boiler tube through computer simulation; Correcting the computer simulation by comparing the measured high temperature damage information with the virtual high temperature damage information; And setting the boiler operating conditions such that the temperature inside the boiler has a uniform distribution through the corrected computer simulation.

In addition, the sensor is characterized in that the degree of tissue change or deformation at high temperature or the degree of diffusion at high temperature as the sensing criterion of high temperature damage.

In addition, the computer simulation is characterized in that it includes computational fluid dynamics (CFD), finite element stress analysis (FEM) and coupled techniques.

In addition, the correcting of the computer simulation may include correcting a constant of an analysis technique used for the computer simulation.

In addition, the setting of the boiler operating conditions may include calculating operating conditions in which the temperature inside the boiler has a uniform temperature distribution through a corrected computer simulation technique; And applying the calculated operating conditions to the power plant boiler.

The driving condition may include at least one of an inclination angle, a fuel injection amount, and an air amount of the tilting burner.

On the other hand, the operating system of the power plant boiler of the present invention for achieving the above object includes a sensor installed near the power plant boiler tube or boiler tube, and a computer simulation unit for computer simulation of the power plant boiler, the computer simulation unit is the sensor It is characterized by calculating the combustion conditions of the power plant boiler on the basis of the measured high temperature damage information.

According to the operating method of the power plant boiler of the present invention as described above, there are the following effects.

Computer simulations can be used to establish combustion conditions that ensure a uniform distribution of the internal temperature of power plant boilers.

Using actual high temperature damage information of the power plant boiler, computer simulations are performed under substantially the same conditions as the actual power plant boiler operating conditions.

By using a diffusion sensor, high temperature damage information can be obtained even in a high temperature environment inside a boiler.

1 is a flow chart of a plant operation according to the prior art

2 is a perspective view of a boiler tube according to the prior art

3 is a flowchart for performing computer simulation according to a preferred embodiment of the present invention.

** Description of symbols for the main parts of the drawing **

1: call bunker 2: grinding machine

3: tilting burner 4: preheater

5: cutting machine 6: superheater

7: reheater 8: air preheater

10 boiler 11 air supply

12 air duct 20 high pressure turbine

25 medium pressure turbine 27 low pressure turbine

30: generator 40: dust collector

50: steel pipe

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

For reference, among the configurations of the present invention to be described below, the same configuration as the prior art will be referred to the above-described prior art, and a detailed description thereof will be omitted.

First, the computer simulation unit receives accumulated measured high temperature damage information of the boiler tube through a boiler tube or a sensor installed near the boiler tube. Here, high temperature damage means cumulative damage caused by the boiler tube being exposed to high temperature during operation. More preferably, it is expressed as ΣT (t) dt as the sum of the temperatures of the boiler tubes during the operation time. Where t is any operating time and T (t) is the temperature of the boiler tube at any operating time.

The boiler tube is a tube installed inside the boiler and heated by the combustion gas in the combustion chamber, and includes a preheater, a superheater, a reheater, and a coal cutter.

The sensor installed near the boiler tube or the boiler tube is a sensor based on sensing of temperature change or deformation at high temperature, or a sensor based on sensing temperature at high temperature.

In the present embodiment, the degree of tissue change or deformation at high temperature is defined as the deformation sensor based on the sensing criterion of high temperature damage.

A strain sensor installed near the boiler tube or boiler tube measures the degree of tissue deformation that occurs as the sensor is exposed to high temperatures, thereby measuring the average temperature of the environment in which the sensor is exposed.

In this embodiment, a sensor in which the degree of diffusion at high temperature is the sensing criterion for high temperature damage is defined as a diffusion sensor.

The diffusion sensor installed in the boiler tube is formed by bonding two or more kinds of metals having different components to each other and forming a diffusion layer in a high temperature environment. The metal is selected from at least one of Fe, C, Ni, CO, and Cr. However, the metal component is not limited thereto, and may be appropriately selected in consideration of the diffusion speed and the size of the diffusion sensor.

The diffusion sensor is a sensor in which the formation rate of the diffusion layer varies according to the exposure temperature. The total thickness of the diffusion layer varies according to the absolute value of the temperature at which the diffusion sensor is exposed, and the layer thicknesses of the diffusion layer vary according to the relative change of the exposed temperature. .

In a preferred embodiment, the first metal of the Fe component and the second metal of the C component are bonded to each other to form a diffusion sensor.

Since such a sensor does not require a separate electrical connection (wire), it is advantageous to obtain temperature information in a high temperature environment such as a power plant boiler.

In addition, the sensor can be manufactured in a small size of less than 10 cm 2, even if the sensor is installed near the boiler tube or boiler tube does not affect the thermal characteristics of the boiler tube.

A plurality of sensors are installed at predetermined intervals near the boiler tube or the boiler tube. It is desirable that the sensor be installed more in the boiler tube where the temperature fluctuates. For example, the number of boiler tubes may vary in the order of superheater> reheater> coalizer> preheater. In particular, the mounting position of the sensor is preferably installed in a position to form a high temperature distribution by predicting the temperature distribution inside the boiler by performing a computer simulation technique to be described later.

After operating the boiler for a predetermined time, the operation of the power plant boiler is temporarily stopped and the sensors installed in the boiler tube are collected.

Accumulated measured high temperature damage of the boiler tube is obtained from the collected sensors by measuring tissue deformation, degree of change or thickness of the diffusion layer, and resistance change of the diffusion layer.

Accumulated measured high temperature damage information is input to a computer simulation part.

The computer simulation unit receiving the accumulated measured high temperature damage information performs the computer simulation according to the flowchart of FIG. 3. 3 is a flowchart for performing computer simulation according to a preferred embodiment of the present invention.

First, computer simulation is performed (100). Computation simulation is performed to calculate virtual high temperature damage information of the boiler tube (200).

Computer simulation simulates a real-world power plant boiler to obtain virtual high temperature damage information based on a computer, and simulates under the same operating conditions as that of calculating actual high temperature damage information.

The analytical techniques used in computer simulations include computational fluid dynamics (CFD), finite element stress analysis (FEM), and linking techniques that connect them.

Computational fluid dynamics (CFD) analyzes the flow of combustion gases in a combustion chamber and computes fluid temperature distribution near the boiler tube through computational fluid dynamics (CFD).

On the other hand, there is a certain difference between the fluid temperature near the boiler tube and the metal temperature of the boiler tube. Therefore, the temperature difference between the two is corrected using the linkage technique. The linkage technique is to correct the fluid temperature to metal temperature, and the metal temperature corrected by the linkage technique is substituted into the metal temperature condition of the finite element stress analysis (FEM).

Finite element stress analysis (FEM) calculates virtual high temperature damage information of a boiler tube based on the metal temperature of the boiler tube.

Computational simulation using CFD, coupling technique, and finite element stress analysis (FEM) is used to calculate the accumulated virtual high temperature damage information experienced by the boiler tube at high temperature.

The accumulated virtual high temperature damage information calculated through the computer simulation is compared with the measured high temperature damage information (300). The accumulated measured high temperature damage information and the accumulated virtual high temperature damage information are compared to determine whether the accumulated virtual high temperature damage information is substantially the same as the accumulated measured high temperature damage information.

If the virtual high temperature damage information is not the same as the measured high temperature damage information, the analysis technique of the computer simulation is corrected (400). Here, calibrating the analysis technique of computational simulation includes calibrating the constants used in computational fluid dynamics (CFD), coupling techniques, and finite element stress analysis methods. In particular, by correcting the constants of the linkage technique, computer simulations simulate the actual power plant boilers substantially the same. Compute the simulated high temperature damage information by computer simulation with the corrected computer simulation method. This process is intended to bring the computer simulation technique closer to the actual power plant boiler.

If it is determined that the virtual high temperature damage information is the same as the measured high temperature damage information, computer simulation is performed through the corrected computer simulation (500).

As a result of the computer simulation, it is determined whether the temperature distribution inside the boiler is uniform (600).

If the temperature inside the boiler does not form a uniform temperature distribution, the operating conditions are changed (700), and computer simulation is performed again.

Boiler operating conditions include especially combustion conditions.

Combustion conditions include the tilt angle of the tilting burner, the fuel injection amount and the air amount, and the like, and the combustion conditions are changed to obtain an optimum combustion condition with a uniform temperature distribution.

When the tilt angle of the tilting burner is upward, the temperature of the combustion chamber is increased. When the tilt angle of the tilting burner is downward, the temperature of the combustion chamber is lowered.

In addition, when the fuel injection amount is large, the temperature of the combustion chamber increases, and when the fuel injection amount is small, the temperature of the combustion chamber decreases. The same amount of air is used.

In particular, the inclination angle of the tilting burner can be set differently for each tilting burner, and the internal temperature distribution of the combustion chamber varies according to the inclination angle of each tilting burner.

That is, the temperature distribution of the entire boiler varies according to the inclination angle of the tilting burner, the fuel injection amount and the air amount, and in particular, the inside of the boiler may have a uniform temperature distribution by adjusting the inclination angle of the tilting burner.

If it is determined that the temperature distribution inside the boiler has a uniform distribution as a result of the computer simulation, the combustion conditions at that time are stored (800).

Then, the stored combustion conditions are applied to the actual power plant boiler, and set as the power plant boiler operating conditions.

The power plant is operated for a predetermined operating time under the combustion conditions set as described above.

Meanwhile, in order to verify whether the set combustion condition is an optimum combustion condition, a new diffusion sensor is attached to the boiler tube before the power plant is operated to operate the power plant for a predetermined time, and after the predetermined time elapses, the diffusion sensor is analyzed and analyzed. The combustion conditions of the boiler can be readjusted.

According to such a configuration, there are the following advantages.

By using a diffusion sensor or a deformation sensor, it is possible to obtain temperature information that a boiler tube receives even in a high temperature environment of a power plant boiler. This makes it possible to pinpoint the point at which hot breakage of the boiler tube is expected to occur and to know the temperature distribution inside the actual power plant boiler.

In addition, since the temperature information by the diffusion sensor or the deformation sensor, the temperature information can be obtained even if the internal temperature of the power plant boiler is very high temperature, especially temperature can be measured even for boilers 1000 ℃ or more. Therefore, the configuration is more suitable for a high capacity power plant.

In addition, the computer simulation is corrected based on the high temperature damage information of the measured boiler tube so that the computer simulation matches the actual power plant boiler. In this way, the computer simulation can closely simulate the actual power plant boiler.

Closer to real-world computer simulations, it is possible to obtain operating conditions in which the internal temperature of a power plant boiler is uniform. In particular, it is possible to easily obtain the combustion conditions with a uniform distribution while changing the combustion conditions of the computer simulation.

Since the combustion conditions predicted by the computer simulation are set to the combustion conditions of the actual power plant boiler, a uniform temperature distribution is formed even in the actual power plant boiler.

This not only prevents damage caused by non-uniform temperature inside the boiler, but also computerized simulation based on the actual temperature distribution inside the boiler, thereby making it possible to accurately predict the failure of the boiler tube.

As described above, although described with reference to a preferred embodiment of the present invention, the present invention can be variously modified or modified without departing from the spirit and scope of the present invention described in the claims Those skilled in the art will appreciate.

The present invention can be used for the operation of the power plant boiler, in particular can be used for the optimal operation of the thermal power plant.

Claims

Receiving accumulated measured high temperature damage information of the boiler tube through a boiler tube or a sensor installed near the boiler tube;

Receiving accumulated virtual high temperature damage information of the boiler tube through computer simulation;

Correcting the computer simulation by comparing the measured high temperature damage information with the virtual high temperature damage information;

Setting a boiler operating condition such that the temperature inside the boiler has a uniform distribution through the corrected computer simulation

Power plant boiler optimal operating method comprising a
The method of claim 1,

The sensor is the optimal operating method of the power plant boiler, characterized in that the degree of tissue change or deformation at high temperature or the degree of diffusion at high temperature as the sensing criteria of high temperature damage.
The method of claim 1,

The computational simulation method of the power plant boiler, characterized in that it includes computational fluid dynamics (CFD), finite element stress analysis (FEM) and linkage techniques
The method of claim 1,

Compensating the computational simulation is the optimal operating method of a power plant boiler, characterized in that for correcting the constants of the analysis method used for the computational simulation
The method of claim 1,

Setting the boiler operating conditions,

Calculating operating conditions in which the temperature inside the boiler has a uniform temperature distribution through a corrected computer simulation technique;

Optimal operating method of the power plant boiler comprising the step of applying the calculated operating conditions to the power plant boiler
The method of claim 5,

The operating condition is an optimal power plant boiler operating method comprising at least one of the tilt angle of the tilting burner, fuel injection amount, air amount
In the operating system of the power plant boiler,

Sensor installed near the power plant boiler tube or boiler tube,

Comprising a computer simulation unit for computer simulation of the power plant boiler,

The computer simulation unit calculates a combustion condition of a power plant boiler based on measured high temperature damage information of the sensor.
The method of claim 7, wherein

The sensor is the operating system of the power plant boiler, characterized in that the degree of tissue change or deformation at high temperature or the degree of diffusion at high temperature as the sensing criteria of high temperature damage.