KR101557591B1 - Method and apparatus for controlling flow rate of fuel in drum boiler - Google Patents

Abstract

The present specification discloses a method and an apparatus for controlling the flow rate of fuel in a drum boiler which generates vapor corresponding to the requirement of a load by supplying fuel. The method according to the present invention includes a step of dividing an entire range where a load from an initial load to a target load is rejected, into several ranges and setting them and a step of controlling the supply of fuel to a drum boiler according to the flow rate of fuel mapped to the ranges. According to the disclosed content, the flow rate of fuel supplied to the drum boiler can be changed according to the rejection of a load. Therefore, a drum level can be stably controlled.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and an apparatus for controlling a fuel supply rate of a drum boiler,

The present invention relates to a method and an apparatus for controlling the fuel supply speed of a drum type boiler and more particularly to a method and apparatus for controlling a fuel supply speed of a drum type boiler, In accordance with the present invention.

A boiler is a device that generates steam at rated pressure and temperature by generating energy by burning fossil fuel and air. Especially, in order to operate the drum boiler normally, it is necessary to balance the quantitative balance of water in the drum and the heat balance Should be inevitably maintained.

FIG. 1 is a view showing a configuration of a drum level control apparatus of a conventional drum boiler according to a conventional embodiment.

As shown in FIG. 1, the drum level of the existing boiler was controlled by the control circuit configured with the drum level measurement value, the main steam flow rate, and the feed flow rate as basic data, but the boiler frequently operated and stopped, The load of the drum was often dipped or increased rapidly, thereby causing the drum level to drop or increase rapidly.

In particular, when there is a problem in the operation of the main equipment of the plant, a load runback which greatly transforms the load to a load that can be driven by the remaining auxiliary devices is generated, and this load runback improves the system stability However, in the plant control aspect, the drum level becomes unstable due to a drastic decrease in the number of drums, unstable steam temperature, pressure change, and the like.

As shown in FIG. 2-1, when the load runback is started, since the drum level temporarily decreases, the inflow water feed amount increases, but the increase amount is not sufficient to maintain the drum level, Level, LTL), resulting in boiler trips.

2-1, if the drum level low trip is avoided due to an increase in the feed water flow rate, even if the drum level is higher than the upper limit level (HTL) even after the load runback situation is ended, Lt; / RTI >

2-3 show graphs in which the current load (RL) outputted in the load runback situation is converted to the target load (TL) in the load runback end situation, and Figs. 2-4 show a graph in which the current load Fuel supply rate.

As shown in FIGS. 2-4, in the conventional drum boiler, when the load runback occurs, the remaining amount of fuel is controlled to a predetermined target fuel supply speed while the target load TL can be attained. However, A problem that acceleration of level is accelerated occurs.

Korean Patent Publication No. 10-2001-0018743 (published on Mar. 14, 2001)

In order to solve the above-mentioned problems, the present invention provides a method and apparatus for controlling the supply speed of fuel flowing into a boiler so as to stably maintain the drum level in a situation where there is a charge of a load.

That is, it is an object of the present invention to provide a technical configuration that determines a fuel supply speed according to a detected value of a load to be detected, and thereby adjusts a change value of a drum level of a boiler to be raised or lowered to maintain a drum level.

The present invention provides a method of adjusting a fuel supply speed of a drum boiler provided in a power plant and supplying fuel (Fuel) to generate steam corresponding to a demand of an initial load, And setting a plurality of intervals by dividing the entire interval into which the load is ignited, and controlling the supply of fuel to the drum boiler according to the fuel supply rate mapped to each of the plurality of intervals.

The method includes the steps of detecting a charged load, determining an interval corresponding to a load to be detected from among a plurality of intervals, and generating a control signal such that the fuel is supplied according to the supply rate of the fuel mapped to the determined interval As shown in FIG.

Further, the supply rate of the mapped fuel is mapped so that the fuel is supplied at the first fuel supply speed in the first section in which the load is ignited, and in the second section following the first section, the second fuel And the controlling step may control the fuel regulator such that the fuel is supplied at a fuel supply rate mapped in an interval in which the load belongs.

The present invention also provides a fuel supply speed control apparatus for a drum boiler provided in a power plant and generating steam corresponding to a request for an initial load upon receiving fuel, A plurality of periods are set by dividing the entire section of the load that is caught until the target load is reached from the load and the initial load, and the fuel is supplied to the drum boiler in accordance with the fuel supply rate mapped to each of the plurality of sections, And a control unit for controlling the control unit.

When the load required by the power plant is to be reduced from the initial load to the target load in accordance with the embodiment of the present invention, by adjusting the fuel supply rate by the fuel supply rate control method, the fuel supply rate corresponding to the load . As a result, it is possible to stably control the change of the drum level value in a situation where the load is turned off, thereby preventing the drastic change in the drum level.

FIG. 1 is a view showing a configuration of a drum level control apparatus of a conventional drum boiler according to a conventional embodiment.
2 is a diagram showing a response of a process in a load runback situation according to the conventional embodiment.
FIG. 3 is a schematic view of a system including a fuel amount adjusting apparatus for a drum boiler according to an embodiment of the present invention. Referring to FIG.
FIG. 4 is a functional diagram of the configuration of FIG. 3 according to an embodiment of the present invention.
5 is a diagram showing the response of a process in a load runback situation according to an embodiment of the present invention.
FIG. 6 is a functional block diagram of a system for controlling a drum level by adjusting a fuel supply rate of a drum boiler according to an embodiment of the present invention. Referring to FIG.
7 is a flowchart illustrating a method of controlling the fuel supply rate of a drum boiler according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Various aspects of the invention are described below. It is to be understood that the inventions set forth herein may be embodied in a wide variety of forms and that any particular structure, function, or all of the presented features are illustrative only. It will be understood by those skilled in the art that on the basis of the inventions set forth herein, one aspect disclosed herein may be implemented independently of any other aspects, and that two or more such aspects may be implemented in various ways ≪ / RTI > For example, an apparatus may be implemented or a method may be practiced using any number of aspects set forth herein. In addition, or in addition to one or more aspects described herein, or with the aid of structures, functions, or structures and functions other than these aspects, such devices may be implemented or such methods may be practiced.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

Throughout the specification, when a part is referred to as being "modified" with an element, it means that the structure of a part can be interchanged with another type of structure unless specifically stated otherwise. Also, to be "changed" means that it can be changed to other embodiments other than the embodiment shown in this specification.

Throughout the specification, certain parts can be used to mean numerical values as the word, and "load", "load" or "load value" can include instantaneous values or loads of the load being measured, May be used interchangeably according to the embodiment shown in this specification.

The boiler system can be divided into three categories: Drum, Downcomers, Recirculation Pump, Furnace, Waterwall, Primary Superheater, Reheater, Reheater Spray, Economizer, Air Preheater, Forced Draft Fan, and Induced Draft Fan. These modules can be divided into 12 modules.

The boilers described in the embodiments of the present invention are oil fired boilers, which are collectively referred to as boilers using oils such as kerosene, diesel, and heavy oil as fuels, coal-fired boilers (collectively referred to as coal-fired boilers) coal fired boilers) or boilers using other fuels.

FIG. 3 is a schematic view of a system including a fuel amount adjusting apparatus for a drum boiler according to an embodiment of the present invention. Referring to FIG.

As shown in FIG. 3, the present invention can determine the fuel supply rate with the detected load as an input value. In addition, the drum level change amount can be calculated based on the determined fuel supply speed, and the drum level value obtained by adding the drum level determined by the calculated drum level and the fluid amount of the existing drum can be compared with the target drum level. The control unit 120 may control the fuel supply rate to compensate for the error in the comparison process.

FIG. 4 is a functional diagram of the configuration of FIG. 3 according to an embodiment of the present invention.

4, the drum level control system according to the present invention includes a fuel supply rate control device 100, a load detection unit 200, a load runback detection unit 250, and a database 400 have.

The fuel supply speed control apparatus 100 may include a fuel control unit 110 and a control unit 120.

The fuel controller 110 may control the supply rate of the fuel flowing into the furnace of the boiler through the control of the controller 120. In particular, it is possible to control the amount of fuel during the load deceleration from the current output load to the target load in a load runback situation where the boiler system load is triggered.

The furnace is a place where the fuel and air are burned to convert the energy of the fuel into heat energy. The heat transfer in the furnace is by radiation, and the heat can be copied to the water cooling wall and the primary superheater. At this time, the permutation transfer may be the same as the decrease in the heat capacity of the furnace combustion gas.

The water cooling wall can be a complete recirculation structure with a tube located between the circulation pump and the drum. In the water-cooling wall, the circulating water supplied from the circulation pump is heated until it reaches the saturation state, and after reaching the saturated state, the quality of the steam can be improved. The density and saturation temperature of the water in the drum can be measured by the average density of the water cooling wall and the saturation temperature.

5 is a diagram showing the response of a process in a load runback situation according to an embodiment of the present invention.

FIG. 5-2 is a graph showing that the load required from the initial load to the target load over time in the load runback situation is detected. FIG. As shown in FIG. 5-2, in the load runback situation, the load is detected at a capacity capable of generating power from the initial load to the target load, and the control unit 120 divides the entire section, The intervals can be set. Hereinafter, the entire section in which the load is detected is divided into two sections, but the present invention is not limited thereto.

According to one embodiment of the present invention, a system is provided in which the load of the present device is reduced in a situation where a load runback occurs due to the shutdown of one of two feedwater pumps having a load capacity of 60% You can learn about the fuel amount control. In the load runback situation, the load that a single feed pump having a load capacity of 60% can afford is set to a target load capacity of 50%. Thus, a load runback involving convulsions with a load set to 100% to 50% may occur.

According to an embodiment of the present invention, the section (1) (section 1) shown in FIG. 5-2 is a case where the load of the power plant is 80% (Second section) is a graph showing a case in which the load demand of the power plant reaches 50% from the case where the load demand of the power plant is 80%.

FIG. 5-4 is a graph showing the fuel supply speed controlled according to the load section. FIG.

Depending on the load that is triggered in the load runback situation, the load demand required for generation is changed and the fuel supply rate can be mapped so that the fuel is supplied at a different feed rate depending on the changing load requirement. That is, the first section may be mapped to be supplied with the fuel at the first fuel supply speed, and the second section may be mapped to the second fuel supply speed different from the first fuel supply speed in the second section following the first section.

According to the embodiment of the present invention, the fuel supply rate of 35% / min is mapped in the section (1) shown in Figs. 5-4 (the period in which the load demand is reduced from 100% to 80%), (1), fuel can be supplied at a fuel supply rate of 35% / min.

In addition, the fuel supply rate of 2% / min is mapped in the section (2) section (the section where the load requirement is reduced from 80% to 50%). If the detected load belongs to section (2) The fuel can be supplied at a fuel supply rate of 2% / min which is further reduced.

More specifically, the control unit 120 may generate a control signal such that fuel is supplied at a first fuel supply speed when the detected load belongs to the first section 1, A control signal is generated to switch the supply rate of the fuel supplied to the drum boiler to the second fuel supply rate when the threshold value of the first boom 2 reaches the boundary value of the first interval 1 and the second interval 2 can do.

Accordingly, the drum level can be stably maintained as compared with the conventional example in which the fuel is supplied at a uniform fuel supply speed in the process of changing the load capacity from 100% to 50%.

Such an effect can be confirmed through the drum level 50 curve shown in the graph of FIG. 5-1. The curve 20 shows a curve when a drum level high / low trip occurs in a conventional load runback, and a curve 50 shows a curve when the drum level is maintained in a stable range according to an embodiment of the present invention. Respectively.

Further, according to another embodiment of the present invention, as shown in FIGS. 5-3, each of the plurality of intervals may be mapped with the fuel supply rate according to time, and the controller 120 So that the fuel is supplied to the drum boiler at a different fuel supply speed.

In this case, the time can be set so as to correspond to a load that is triggered over time, that is, a load demanded by the power plant in real time according to the flow of time.

Further, the fuel supply speed corresponding to the loaded load can generate the table at a predetermined value. The fuel supply speed may be set to correspond to each load or a predetermined load interval depending on the load to be caught, and the table may be stored in the database 400.

The load detecting section 200 can detect the load of the power plant. In particular, it is possible to detect in real time the load that is triggered according to the passage of time.

In a load runback, there may be a target load that converges the load value that is induced from the initial load.

The initial load may include the load required if the plant is operated in a stable state, and the target load may include the load of the plant that the remaining equipment can afford due to malfunction of the auxiliary equipment.

The load runback detection unit 250 can sense that the initial load is caught due to the load run back. Since the load runback is generated by a predetermined system, the load runback sensing unit 250 of the present invention may include a function for sensing an initial load that is triggered by a conventional load runback.

 The database 400 may store a table of fueling rates, each mapped to a plurality of intervals. The fuel supply rate mapped to the plurality of intervals can be determined based on a preset experimental value, and the number of intervals and the fuel supply rate mapped can be changed.

The database 400 may refer to a functional and structural combination of software and hardware that stores information corresponding to each database 400. The database 400 may be implemented as at least one table, and may further include a separate DBMS (Database Management System) for searching, storing, and managing information stored in the database 400. The database 400 may be implemented in various ways such as a linked list, a tree, a relational database, or the like, and may be any data storage medium capable of storing information corresponding to the database 400, Data structures.

FIG. 6 is a functional block diagram of a system for controlling a drum level by adjusting a fuel supply rate of a drum boiler according to an embodiment of the present invention. Referring to FIG.

6, the system of the present invention may include a fuel regulator, a first drum level calculator 310, a second drum level calculator 300, an adder 320 and a comparator 330 .

The controller 120 receives the drum level change value (the sum of the first drum level change value and the second drum level change value), and compensates for the error of the calculated drum level change value, thereby maintaining the drum level constant . Hereinafter, it will be described in detail.

The first drum level calculator 310 can calculate the change value of the drum level based on the combustion of the fuel supplied at the fuel supply speed controlled in accordance with the load section. Specifically, the first drum level change value according to the volume change of the water / steam mixture in the furnace due to the change in the fuel amount can be calculated.

에 의해 산출될 수 있으며, 여기서,

는 t1 시간동안 변화한 화로 내부의 물/스팀 부피 변화에 따른 드럼 레벨 변화값을 나타낼 수 있다.The first drum level change value

, ≪ / RTI > where < RTI ID =

Can indicate the drum level change value according to the water / steam volume change inside the furnace changed during the time t1.

The second drum level calculator 300 may calculate the second drum level change value based on the main steam generation amount and the inflow water feed amount.

The inflow water feed amount measuring device may be connected to the second drum level calculator 300 and may measure the inflow water feed amount flowing into the drum by branching at a Boiler Feed-Water Pump to the second drum level calculator 300 .

The main steam flow meter may measure the main steam flow generated by the high pressure steam due to the combustion of the fuel and transmit it to the second drum level calculator 300.

(여기서,

는 레벨 변환 상수,

는 유입 급수량,

는 주증기 유량을 의미할 수 있다)에 의해 산출될 수 있다.The second drum level change value calculated using the above measured values as an input value is expressed by the following equation

(here,

Is a level conversion constant,

The amount of inflow water,

May mean the main steam flow rate).

The adder 320 may add the second drum level change value to the first drum level change value and output the current drum level change value in real time while the load runback proceeds.

The adder can add the first drum level change value and the second drum level change value by the following equation.

는 t1시간 동안 변화한 현재 드럼 레벨 변화값을 의미한다.here,

Means the current drum level change value changed during the time t1.

The above-mentioned equations can be referred to as a reference for setting a period during which the load is discharged from the initial load to the target load of the present invention and determining the fuel supply rate mapped for each of the plurality of intervals.

That is, according to an embodiment of the present invention, the length of a plurality of sections to which a load to be charged belongs and the fuel supply rate mapped to each section may be determined to be optimized for drum level stability, The first drum level change value, and the second drum level change value.

Further, according to an embodiment of the present invention, the fuel supply rate may be determined based on a drum level value which fluctuates during a predetermined time t1 and a load period in which a load detected after a lapse of time t1 belongs.

The comparator 330 receives the current drum level change value added through the adder 320 and compares the current drum level change value with a predetermined target drum level value. Specifically, the predetermined target drum level value may include a stable drum level value in a situation where the charged load reaches the target load - the runback end situation.

Due to the adjustment of the fuel supply rate corresponding to the load according to the present invention, when the fuel amount is rapidly reduced in the load run-back, the problem of the drastically reduced drum level due to the reduction of the fluid volume of the water- Conversely, if the amount of fuel is slowly reduced, it is possible to prevent a decrease in the drum level caused by an excessive amount of main steam generated relative to the amount of the incoming water.

7 is a flowchart illustrating a method of controlling the fuel supply rate of a drum boiler according to an embodiment of the present invention.

As shown in FIG. 7, the method of the present invention includes a step S710 of detecting occurrence of a load runback, a step S720 of setting an entire section in which a load is detected as a plurality of sections, (S730) of controlling the fuel supply speed, detecting a load (S740), and determining whether the detected load corresponds to the target load (S750).

The step of detecting the occurrence of a load runback (S710) may include a step of determining a load runback situation in which the initial load is caught. In the load runback situation, the load may be determined to a predetermined value by a predetermined system in the existing boiler power generation system.

In the step S720 of setting the entire section in which the load is detected as a plurality of sections, the entire section in which the load from the initial load to the target load is detected may be set as a plurality of sections. Such a plurality of intervals may include at least two intervals, and the number of intervals is not limited.

The step S730 of controlling the fuel supply rate mapped in the section to which the load belongs determines the fuel supply speed mapped in one section of the plurality of sections to which the detected load belongs and controls the fuel to be supplied to the boiler at the fuel supply speed And generating a signal.

The step of detecting the load (S740) may include a process of detecting the load in real time.

The step of determining whether the detected load corresponds to the target load (S750) may include determining whether the detected load is the same as the target load. If the detected load is not the target load, it is possible to determine again the fuel supply speed mapped to the section to which the detected load belongs, and to terminate the control of the fuel supply speed when the detected load corresponds to the target load.

Also, in the case of a coal-fired boiler supplied with pulverized powdered coal through a pulverizer, the pulverized pulverized coal is supplied to the fuel supply unit Time).

On the other hand, according to the present invention, it is possible to obtain the effect of stabilizing the drum level by controlling the fuel supply rate by controlling the amount of pulverized coal supplied without stopping the differentiator when a load runback occurs. In addition, even when the stop of the differentiator is required, the drum level can be maintained more stably by controlling the fuel feed rate by controlling the amount of pulverized coal in the process of sequentially stopping the differentiators which need to stop one by one.

The foregoing description of the present invention is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made without departing from the essential characteristics of the present invention by those skilled in the art. Therefore, the embodiments described in the present invention are intended to illustrate rather than limit the technical spirit of the present invention, and are not intended to limit the technical spirit of the present invention to these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents thereof should be construed as being included in the scope of the present invention.

100: fuel supply speed control device
110: fuel regulator
120:
200: load detector
250: load runback detection unit
300: second drum level calculator
310: first drum level calculator
320: adder
330: comparator
400: Database

Claims (13)

A method of adjusting a fuel supply rate of a drum boiler provided in a power generation plant and supplied with fuel (Fuel) to generate steam corresponding to a request for an initial load,
Setting a plurality of sections by dividing a whole section in which a load is detected until reaching a target load from the initial load;
Controlling the supply of fuel to the drum boiler according to the supply rate of the fuel mapped to each of the plurality of intervals;
Wherein the fuel feed rate of the drum boiler is controlled.
The method according to claim 1,
Detecting the charged load;
Determining an interval corresponding to the detected load among the plurality of intervals; And
Generating a control signal such that the fuel is supplied according to the supply rate of the fuel mapped to the determined interval;
Further comprising the step of adjusting the fuel supply rate of the drum boiler.
The method according to claim 1,
Wherein the supply rate of the mapped fuel is mapped so that the fuel is supplied at a first fuel supply rate in a first section in which the load is ignited and a second fuel supply rate in a second section that is later than the first section is mapped Mapped to the fuel supply rate,
Wherein the controlling comprises:
Wherein the fuel control unit controls the fuel control unit so that the fuel is supplied to the fuel supply rate mapped in an interval in which the load belongs.
The method according to claim 1,
Sensing the ignition of the initial load by a load runback to adjust the fuel supply rate;
Further comprising the step of controlling the fuel supply speed of the drum boiler.
The method according to claim 1,
Calculating a first drum level change value of the drum boiler based on a change in a flow rate inside the furnace according to the fuel supply rate; And
Determining the fuel supply rate based on the first drum level change value;
Further comprising the step of controlling the fuel supply speed of the drum boiler.
6. The method of claim 5,
Wherein the first drum level change value is calculated by the following equation,

,
here

Is a first drum level change value in accordance with a change in internal water / steam volume during the time t1,
The fuel supply speed may be,
Wherein the fuel supply rate is a fuel supply rate that is mapped to a period in which a load detected after the elapse of the time t1 belongs.
The method according to claim 1,
Calculating a second drum level change value of the drum boiler using an input water feed rate measurement value and a main steam flow rate measurement value as input values;
Determining the fuel supply rate based on the second drum level change value;
Further comprising the step of controlling the fuel supply speed of the drum boiler.
8. The method of claim 7,
The second drum level change value is calculated by the following equation,

here,

Is a level conversion constant,

The amount of inflow water,

Represents the main steam flow rate,
The fuel supply speed may be,
Wherein the fuel supply rate is a fuel supply rate that is mapped to a period in which a load detected after the elapse of the time t1 belongs.
The method according to claim 1,
Calculating a first drum level change value for a predetermined time t1 based on the fuel supply rate;
Adding the second drum level change value calculated during the time t1 to the calculated first drum level change value based on the inflow water feed amount measurement value and the main steam flow rate measurement value; And
Determining a fuel supply rate mapped to an interval in which the load detected after the time l1 elapses based on the added change in the drum level;
Further comprising the step of controlling the fuel supply speed of the drum boiler.
10. The method according to any one of claims 1 to 9,
Wherein the drum boiler is supplied with pulverized powdered coal as fuel through a pulverizer.
11. The drum boiler according to claim 10,
Wherein the control unit controls the fuel supply speed in a state in which the operation of the differentiator is not stopped or controls the fuel supply rate in a state of sequentially stopping the operation of the differentiator.
An apparatus for controlling a fuel supply speed of a drum boiler provided in a power generation plant and generating steam corresponding to a demand of an initial load by receiving fuel,
A fuel regulator for regulating a supply rate of fuel supplied to the drum boiler;
A plurality of sections are set by dividing a whole section of the load to be inspected until reaching the target load from the initial load so that fuel is supplied to the drum boiler according to the fuel supply rate mapped to each of the plurality of sections A control unit for controlling the fuel control unit;
And a control unit for controlling the fuel supply speed of the drum boiler.
13. The method of claim 12,
And a load detector for detecting the load to be turned on,
Wherein,
Wherein the controller is configured to determine a section corresponding to the detected load among the plurality of sections and to generate a control signal to supply fuel according to the fuel supply rate mapped to the determined section, .

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