KR20200030504A - Fuel reduction rate output system, fuel reduction rate output method and fuel reduction rate output program - Google Patents

Abstract

 A fuel reduction rate output system that calculates a fuel reduction rate related to a fuel reduction response applied to a boiler combustion control system, records the history of the measured main steam pressure as the main steam pressure history, and calculates the deviation between the main steam pressure history and the measured main steam pressure. A standard deviation for calculating a standard deviation based on a deviation history determining unit outputting the main steam pressure history whose deviation is within a predetermined range as a control main steam pressure history, and a control main steam pressure history output by the deviation determination unit A fuel for calculating and outputting a fuel reduction rate based on a standard expression representing a relationship between the standard deviation improvement rate and the fuel reduction rate, and calculating a standard deviation improvement rate based on the standard deviation calculated by the calculation unit and the standard deviation calculation unit It has a reduction rate output.

Description

Fuel reduction rate output system, fuel reduction rate output method and fuel reduction rate output program

The present invention relates to a technology for controlling the combustion of a boiler, and in particular, it is applied to a fuel reduction rate output system, a fuel reduction rate output method, and a fuel reduction rate output program for calculating a fuel reduction rate obtained by improving the boiler efficiency. It is related to the following techniques.

For example, in the case of obtaining energy using a boiler facility, fuel (solid fuel such as coal, liquid fuel, or gaseous fuel) is supplied to the boiler for combustion, absorbing the heat in a heat exchanger, and generating steam to generate heat. The generated steam is converted, for example, from thermal energy to rotational motion by supplying it to a steam turbine, and used for power generation by a generator, etc. The fuel input to the boiler is the load demand [eg, power generation As the demand amount (MWD, Mega Watt Demand), sometimes referred to as load demand (MWD) below, and the amount of fuel input to the boiler (below, when the boiler input instruction value (BID, Boiler Input Demand) is described) ) Is determined by the fuel function FX, which is a relational expression between.

Here, due to various factors related to the boiler equipment, for example, changes in fuel properties or calorific value due to fuel replacement, boiler pollution, soot blower, water temperature, etc. In some cases, fluctuations may occur in the operating state of the boiler, especially the pressure of the main steam. Therefore, the fuel of the fuel input obtained by the fuel function FX is supplied to the boiler, the generated main steam pressure is measured, and PID (Proportional) is based on the difference between the main steam pressure and the preset main steam pressure. -Integral-Differential) Control to obtain a feedback correction amount by control and add it to the load demand amount to correct the fuel input to the boiler is generally performed.

As a technique related to this, for example, in Japanese Patent No. 4522326 (Patent Document 1), a plurality of values are stored while sequentially updating the ratio or difference between values before and after feedback correction, and fuel is stored from the stored values. It is described that a correction coefficient is obtained and a value after feedback correction is corrected by the correction coefficient. By doing so, it is possible to correct to an appropriate fuel input in consideration of the change in the thermal efficiency of the boiler due to the influence of various factors.

In addition, in Japanese Patent No. 4791269 (Patent Document 2), for example, in a plurality of types of fuel-mixed combustion boilers, the fuel correction coefficient for correcting the value after feedback correction is subdivided into three elements, thereby making fuel units In response to the difference in the heat efficiency of the boiler according to the difference in the heat amount and the change in the mixing rate, the contents of correction of the fuel input to the boiler are described.

Patent Document 1: Japanese Patent No. 4522326 Patent Document 2: Japanese Patent No. 4791269

For example, according to the prior arts such as Patent Documents 1 and 2, the value (or other control value) of the load demand amount (or other control value) before and after feedback correction is frequently performed for a change in the thermal efficiency of the boiler due to the influence of various factors. By comparing and measuring it, it is possible to determine the value and correct the value after feedback correction based on the determination result to obtain a correction coefficient value for optimization by self-learning.

By optimizing control using these correction factors, it is possible to improve the efficiency of the boiler, but in order to grasp the degree of improvement of the efficiency of the boiler, it is necessary to perform a performance test and actually measure it. Specifically, for example, the operation / non-operation of the energy-saving control function is changed, and the fuel consumption and the amount of steam generated are compared between the operation time and the non-operation time to calculate the fuel reduction rate. But. Methods that require such performance testing are cumbersome, and fuel reduction rates cannot be estimated in real time while driving.

Therefore, an object of the present invention is to provide a fuel reduction rate output system, a fuel reduction rate output method, and a fuel reduction rate output program that enable real-time output of a fuel reduction rate, ie, an energy saving rate, obtained by improving controllability of a boiler.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

Briefly, the outline of a representative one of the inventions disclosed in the present application is as follows.

Boiler combustion control system according to an exemplary embodiment of the present invention, the fuel for calculating the fuel reduction rate corresponding to the fuel reduction applied to the boiler combustion control system to supply the fuel of the fuel input to the boiler calculated for the load demand to the boiler As a reduction rate output system, the history of the measured main steam pressure, which is the measured main steam pressure of the boiler, is recorded as the main steam pressure history, and the deviation between the main steam pressure history and the measured main steam pressure is calculated, and the deviation is predetermined. Deviation determination unit for outputting the history of the main steam pressure within the range of as the history of the control main vapor pressure, and standard deviation calculation unit for calculating the standard deviation by the history of the control main vapor pressure output by the deviation determination unit And, based on the standard deviation calculated by the standard deviation calculation unit standard deviation improvement rate Based on the standard equation representing sakgamyul fuel output unit that outputs to calculate the fuel sakgamyul; will have a.

The present invention can also be applied to the fuel reduction rate output method in the fuel reduction rate output system as described above, and the fuel reduction rate output program that operates the computer as the fuel reduction rate output system.

Among the inventions disclosed in the present application, the effects obtained by representative ones are briefly described below.

That is, according to the exemplary embodiment of the present invention, it is possible to output in real time the fuel reduction rate obtained by improving the controllability of the boiler, that is, the energy saving rate.

1 is a view showing an outline of a configuration example of a fuel reduction rate output system that is one embodiment of the present invention.
2 is a view showing an example of the relationship between the improvement rate of the standard deviation of the main steam pressure and the fuel reduction rate in one embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in the whole drawings for describing the embodiments, the same parts are generally given the same reference numerals, and repeated explanations are omitted. Although not, there are cases where the same reference numerals are used.

<System configuration>

1 is a view showing an outline of a configuration example of a fuel reduction rate output system that is one embodiment of the present invention. In Fig. 1, control of the boiler 2 is performed by a conventional boiler combustion control system 2. The boiler control system 4 uses the load demand amount MWD as an input and determines a boiler input indication value BID that is a fuel input amount to the boiler by a fuel function (not shown). For example, when this boiler combustion control system 2 is newly renewed or additionally installed, or as shown in Patent Literatures 1 and 2, and the like to improve controllability, fuel reduction is expected. When the response (hereinafter referred to as `` fuel reduction contribution response '' may be collectively referred to as hereinafter), the fuel reduction rate output system 1 is based on the standard deviation of the main steam pressure of the boiler 2, as described later. Then, the fuel reduction rate 15 is calculated and output in real time.

In addition, the example of FIG. 1 is configured to be added to the boiler combustion control system 4 using the fuel reduction rate output system 1 as a separate system, but is integrated as part of the boiler combustion control system 4. It may be configured in a form. In the example of Fig. 1, the fuel reduction rate output system 1 is configured to output the calculated fuel reduction rate 15 as data, but it is displayed on a display not shown in a predetermined format or layout, or a printer. By having a display section that is output by printing on or the like, the fuel reduction rate 15 (or fuel reduction amount) can be grasped instantaneously.

The fuel reduction rate output system 1 may be configured as, for example, a value mounted by hardware of a semiconductor circuit, a microcomputer, or the like, not shown, which performs processing of each function described later. Alternatively, middleware such as an operating system (OS) deployed in a memory of a central processing unit (CPU), which is not shown and configured by a general-purpose server device or a virtual server built in a clouding computer service, or software running therefrom By executing, the processing of each function described later may be performed.

The hardware mounting and software mounting may be appropriately combined to limit the configuration, and some functions may be mounted in different cases, and the cases may be connected to each other by a communication cable or the like. That is, the mounting form of the fuel reduction rate output system 1 is not particularly limited, and can be suitably flexibly configured according to the environment of the plant.

As shown in the figure, the fuel reduction rate output system 1 includes, for example, a deviation determination unit 11 mounted by hardware or software, a standard deviation calculation unit 12, a fuel reduction rate output unit 13, and the like. Each part has. In addition, it has data such as a main steam pressure history 14 mounted as a database or a file or table recorded in a memory or HDD.

<Calculation of fuel reduction rate>

As described above, the fuel reduction rate output system 1 of this embodiment has a response to fuel reduction contribution to the boiler combustion control system 2 (or by other systems added to the boiler combustion control system 2, etc.). It is presumed to be made. When energy saving is achieved by responding to these fuel reduction contributions, in particular, when controllability is improved by conventional techniques such as those described in Patent Documents 1 and 2, fluctuations in the pressure of the main steam generated by the boiler 2 It becomes small. Accordingly, the combustion state in the burner of the boiler 2 or the state variation of the entire unit including the steam turbine 3 for power generation is caused to sleep, and as a result, fuel consumption is reduced.

In such a boiler combustion control system 4, the magnitude of the state variation of the entire unit can be considered in relation to the fuel reduction rate. Therefore, in the fuel reduction rate output system 1 of this embodiment, the estimated value of the fuel reduction rate is calculated by the following method.

As shown, the current measured main steam pressure PV is input from the main steam pressure transmitter PX to the deviation determination unit 11 of the fuel reduction rate output system 1. In the deviation determination unit 11, for example, at regular intervals, such as once a minute, the measured main steam pressure PV and the past constant time recorded in the main steam pressure history 14 (for example, For example, compare the history of the main steam pressure in the past 80 minutes). In addition, the main steam pressure history 14 has at least a measurement value of the main steam pressure over the past time period (for example, 60 minutes) at a frequency equal to or greater than the predetermined time period (for example, 1 minute interval). It shall be recorded.

The deviation determination unit 11 extracts, from the main vapor pressure history 14, the history of the main vapor pressure in the range of about ± 5%, for example, with respect to the current measured main vapor pressure PV. Count the number. If the number is more than a predetermined number (for example, more than half of the total historical data that became the parent population of the extraction (in other words, more than half of the predetermined period), the main vapor pressure is the current measured main vapor) It is judged that it is controlled in a stable state with a value equal to the pressure (PV), and the standard deviation calculation unit (information of the history of the extracted main steam pressure (hereinafter sometimes referred to as `` control main steam pressure '')) 12).

The standard deviation calculation unit 12 calculates a standard deviation based on the input history of the control main steam pressure, and outputs it to the fuel reduction rate output unit 13. The standard deviation is, for example, equation;

Standard deviation improvement rate = 100-(Control standard deviation / standard deviation before response * 100; calculated as standard deviation improvement rate (%). Here, the control standard deviation is the input of the history of the control main steam pressure. The standard deviation is the standard deviation of the history of the main steam pressure in the state before the response to the fuel reduction contribution, and the standard deviation before the response (ie, the target fuel). The control main steam pressure before the reduction contribution response is achieved, for example, is obtained and recorded in advance before the target fuel reduction contribution response is made, or set as a predetermined variable function and the coefficient can be changed appropriately. It is also good.

The fuel reduction rate output unit 13 calculates and outputs an estimated value of the fuel reduction rate according to a predetermined formula from the input standard deviation improvement rate.

Fig. 2 is a diagram showing an example of the relationship between the improvement rate of the standard deviation of the main steam pressure of this embodiment and the fuel reduction rate. The graph of FIG. 2 shows the boiler 2 introduced into each plant, with the horizontal axis (x-axis) as the standard deviation improvement rate (%) of the main steam pressure and the vertical axis (y-axis) as the fuel reduction rate (%). It shows that the actual result when responding to various fuel reduction contributions is plotted. As shown in FIG. 2, it can be seen that the larger the improvement rate of the standard deviation of the main steam pressure, the greater the fuel reduction rate. Then, this correlation can be formulated for each boiler 2 by a linear approximation method as shown (in the example of FIG. 2, "y = 0.0378x +" shown in the figure). 0.1604 ”). In this embodiment, the fuel reduction rate output unit 13 calculates an estimated value of the fuel reduction rate by applying the standard deviation improvement rate input to the linearly approximated reference formula.

In addition, in this embodiment, as shown in Fig. 1, it is configured to have one fuel reduction rate output unit 13, but the fuel reduction rate output unit for each degree of measurement (load band) of the main steam pressure PV. You may make it into the structure which makes (13) a plurality and divides and uses it. Alternatively, a plurality of reference expressions representing the relationship between the standard deviation improvement rate and the fuel reduction rate may be created and used separately for each load band of one fuel reduction rate output unit 13. Further, the reference formula may be set as a predetermined variable function, and the coefficient may be appropriately changed. In this embodiment, the estimated value of the fuel reduction rate (%) is calculated and output, but it is multiplied by the boiler input indication value (BID) (fuel input amount to the boiler 2) and output as the fuel reduction amount. It is also good.

In the above, the invention made by the present inventors has been specifically described by way of examples, but the invention is not limited to the above examples, and it goes without saying that various changes can be made in the law without departing from the gist thereof. For example, the above embodiments have been described for easy understanding of the present invention, and are not necessarily limited to having all the configurations described. In addition, it is also possible to add, delete, or replace other components of some of the components of the above embodiment.

In addition, each of the above structures, functions, processing units, processing means, and the like may be realized in hardware by designing some or all of them with an integrated circuit, for example. In addition, each of the above-described configurations, functions, and the like may be realized in software by interpreting and executing a program in which the processor realizes the respective functions. Information such as programs, tables, and files for realizing each function can be stored in a recording device such as a memory or hard disk, a solid state drive (SSD), or a recording medium such as an IC card, SD card, or DVD.

In the above drawings, the control line and the information line are shown to be considered necessary for explanation, and it is not necessarily shown that the entire control line or information line is mounted.

[Industrial availability]

The present invention can be used in a fuel reduction rate output system for calculating a fuel reduction rate obtained by improving the efficiency of a boiler, a fuel reduction rate output method, and a fuel reduction rate output program.

１… Fuel reduction rate output system, 2 ... Boiler, 3 ... Steam turbine,
４… Boiler combustion control system, 11… Deviation determination unit,
12… Standard deviation calculator, 13… Fuel reduction rate output,
14… Main Steam Pressure History, 15… Fuel reduction rate, PV… Measurement main steam pressure, PX… Main steam pressure transmitter, MWD… Load demand, BID… Boiler input indication

Claims (6)

A fuel reduction rate output system for calculating a fuel reduction rate related to a fuel reduction response applied to a boiler combustion control system that supplies fuel of the fuel input to the boiler calculated with respect to the load demand,
The history of the measured main steam pressure, which is the measured main steam pressure of the boiler, is recorded as the main steam pressure history, the deviation between the main steam pressure history and the measured main steam pressure is calculated, and the deviation is within a predetermined range. Deviation determination unit that outputs the history of the steam pressure as the history of the control main steam pressure,
A standard deviation calculation unit for calculating a standard deviation according to the history of the control main vapor pressure output by the deviation determination unit, and
A fuel reduction rate output for calculating and outputting the fuel reduction rate based on a reference formula representing a relationship between the standard deviation improvement rate and the fuel reduction rate by calculating a standard deviation improvement rate according to the standard deviation calculated by the standard deviation calculation unit A fuel reduction rate output system having a negative; The method according to claim 1,
The reference formula is set for each load band of the boiler, the fuel reduction rate output system. The method according to claim 1 or 2,
The fuel reduction rate output system, wherein the reference formula is set as a predetermined variable function. The method according to any one of claims 1 to 3,
And a display unit for displaying the fuel reduction rate output by the fuel reduction rate output unit. A method for outputting a fuel reduction rate in a fuel reduction rate output system for calculating a fuel reduction rate related to a fuel reduction response applied to a boiler combustion control system that supplies fuel of the fuel input amount to a boiler calculated with respect to a load demand,
The history recording process of recording the measured main steam pressure history, which is the main steam pressure of the boiler, as the main steam pressure history,
The deviation between the main steam pressure history and the measured main steam pressure is calculated, and the deviation of the main steam pressure is within a predetermined range.
Deviation determination process to output as a history of the control main steam pressure,
A standard deviation calculation process for calculating a standard deviation by the history of the control main vapor pressure output by the deviation determination process, and
A fuel reduction rate that calculates and outputs the fuel reduction rate based on a standard expression representing a relationship between the standard deviation improvement rate and the fuel reduction rate, and calculates a standard deviation improvement rate based on the standard deviation calculated by the standard deviation calculation process Output process; A method for outputting a fuel reduction rate. A fuel reduction rate output program that functions as a fuel reduction rate output system for calculating a fuel reduction rate related to a fuel reduction response applied to a boiler combustion control system that supplies fuel of the fuel input amount to a boiler calculated for a load demand to the boiler,
History recording process for recording the measured main steam pressure history, which is the main steam pressure of the boiler, as the main steam pressure history,
Deviation determination processing for calculating a deviation between the main steam pressure history and the measured main steam pressure, and outputting the history of the main steam pressure whose deviation is within a predetermined range as the history of the control main steam pressure,
Standard deviation calculation processing for calculating a standard deviation based on the history of the control main vapor pressure output by the deviation determination processing, and
A fuel reduction rate for calculating and outputting the fuel reduction rate based on a standard expression representing a relationship between the standard deviation improvement rate and the fuel reduction rate by calculating a standard deviation improvement rate based on the standard deviation calculated by the standard deviation calculation process Output processing; A fuel reduction rate output program that causes the computer to run.

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