JP2019002574A - Fuel reduction rate output system, fuel reduction rate output method and fuel reduction rate output program - Google Patents

Abstract

To calculate a fuel reduction rate acquired by improvement of controllability of a boiler in real time.SOLUTION: A fuel reduction rate output system 1 which calculates a fuel reduction rate 15 related to fuel reduction correspondence applied to a boiler combustion control system 4 includes: a deviation determination unit 11 for recording history of a measurement main steam pressure PV as main steam pressure history 14, for calculating deviation of the main steam pressure history 14 and the measurement main steam pressure PV, and for outputting the history of the main steam pressure in which the deviation is in a predetermined range as the history of the control main steam pressure; a standard deviation calculation unit 12 for calculating standard deviation on the basis of the history of the control main steam pressure outputted by the deviation determination unit 11; and a fuel reduction rate output unit 13 for calculating a standard deviation improvement rate on the basis of the standard deviation calculated by the standard deviation calculation unit 12, and for calculating and outputting the fuel reduction rate 15 on the basis of a reference expression showing the relation between the standard deviation improvement rate and the fuel reduction rate.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technology for controlling combustion of a boiler, and in particular, 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 boiler efficiency. It is related to effective technology.

  For example, when acquiring energy using boiler equipment, fuel (solid fuel such as coal, liquid fuel, or gaseous fuel) is supplied to the boiler (furnace) and burned, and the heat is absorbed by the heat exchanger. Generate steam to generate thermal energy. The generated steam is converted from thermal energy into rotational motion by being supplied to a steam turbine, for example, and used for power generation by a generator. The amount of fuel input to the boiler is a load requirement amount (for example, a power generation requirement amount MWD (Mega Watt Demand), and may be referred to as a load requirement amount MWD hereinafter) Then, it is determined by the fuel function FX which is a relational expression between the boiler input command value BID (may be described as “Boiler Input Demand”).

  Here, various factors related to boiler equipment, such as changes in fuel properties and calorific value due to fuel switching, furnace fouling, suit blower, air temperature, etc. cause fluctuations in boiler operating conditions, particularly main steam pressure. May occur. Therefore, the fuel related to the fuel input amount obtained by the fuel function FX is supplied to the boiler, the generated main vapor pressure is measured, and the PID (Proportional-) is based on the difference between this and the preset main vapor pressure. In general, control has been performed in which a feedback correction amount is obtained by Integral-Differential control, and this is added to a load request amount to correct the fuel injection amount to the boiler.

  As a technique related to this, for example, in Japanese Patent No. 4522326 (Patent Document 1), a plurality of ratios or differences between values before and after feedback correction are sequentially updated and stored, and the stored multiple values are used. It is described that a fuel correction coefficient is obtained and a value after feedback correction is corrected by this correction coefficient. Thus, it is possible to correct the fuel injection amount in consideration of changes in the thermal efficiency of the boiler due to the influence of various factors.

  Furthermore, for example, in Japanese Patent No. 4791269 (Patent Document 2), a fuel correction coefficient for correcting a value after feedback correction is subdivided into three elements in a multiple-type fuel mixed combustion boiler. It is described that the amount of fuel input to the boiler is corrected in accordance with the difference in unit calorific value and the difference in boiler thermal efficiency due to the change in the mixed combustion rate.

Japanese Patent No. 4522326 Japanese Patent No. 4791269

  For example, according to prior arts such as Patent Documents 1 and 2, the value of the load request amount MWD before and after the feedback correction (or other control value) is compared as needed for changes in the thermal efficiency of the boiler due to the influence of various factors. It is possible to determine this by measuring, and acquire the value of the correction coefficient for further correcting and optimizing the value after feedback correction based on the determination result by self-learning.

  By optimizing the control using these correction factors, the efficiency of the boiler can be improved. However, in order to grasp the degree of improvement in the efficiency of the boiler, conventionally, a performance test is performed and actually measured. There was a need. Specifically, for example, the operation / non-operation of the control function related to energy saving is switched, the fuel consumption amount and the steam generation amount are respectively compared between the operation period and the non-operation period, and the fuel reduction rate is calculated. However, the method that requires such a performance test is a roundabout, and it is impossible to estimate the fuel reduction rate in real time during operation.

  Accordingly, 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 that can output the fuel reduction rate obtained by improving the controllability of the boiler, that is, the energy saving rate in real time. To provide an output program.

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

  Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.

  A boiler combustion control system according to a representative embodiment of the present invention is a fuel reduction applied to a boiler combustion control system that supplies fuel related to the amount of fuel input to the boiler calculated with respect to the required load amount to the boiler. A fuel reduction rate output system for calculating a fuel reduction rate related to a response, wherein a history of measured main steam pressure that is a measured main steam pressure of the boiler is recorded as a main steam pressure history, and the main steam pressure history and A deviation determining unit that calculates a deviation from the measured main steam pressure, and outputs a history of main steam pressure whose deviation is within a predetermined range as a history of control main steam pressure, and the control output by the deviation determining unit A standard deviation calculation unit that calculates a standard deviation based on a history of main steam pressure, a standard deviation improvement rate calculated based on the standard deviation calculated by the standard deviation calculation unit, and the standard deviation improvement rate and the fuel And fuel reduction rate output unit calculates and outputs said fuel reduction rate based on the reference equation showing the relationship between the reduction rate, and has a.

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

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

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

It is the figure which showed the outline | summary about the structural example of the fuel reduction rate output system which is one embodiment of this invention. It is the figure which showed the example of the relationship between the improvement rate of the standard deviation of the main vapor pressure in one embodiment of this invention, and a fuel reduction rate.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted. On the other hand, parts described with reference numerals in some drawings may be referred to with the same reference numerals although not illustrated again in the description of other drawings.

<System configuration>
FIG. 1 is a diagram showing an outline of a configuration example of a fuel reduction rate output system according to an embodiment of the present invention. In FIG. 1, the control for the boiler 2 is performed by an existing boiler combustion control system 4. The boiler combustion control system 4 receives the load request amount MWD and determines a boiler input command 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 4 is newly updated or additionally installed, or when measures are taken to improve controllability as shown in Patent Documents 1 and 2, etc., fuel reduction can be expected. When a response (hereinafter may be collectively referred to as “a fuel reduction contribution response”) is made, the fuel reduction rate output system 1 reduces the fuel based on the standard deviation of the main vapor pressure of the boiler 2 as described later. The rate 15 is calculated and output in real time.

  In the example of FIG. 1, the fuel reduction rate output system 1 is configured to be added to the boiler combustion control system 4 as an individual system, but is configured to be incorporated as a part of the boiler combustion control system 4. May be. Further, 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 this is displayed on a display (not shown) or printed on a printer in a predetermined format or layout. It is good also as a structure which has a display part which carries out and outputs. By having such a display part, 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 device that is implemented by hardware including a semiconductor circuit (not shown), a microcomputer, and the like that executes processing related to each function described below. Alternatively, it is composed of general-purpose server devices, virtual servers built on cloud computing services, etc., and expanded on memory from a recording device such as an HDD (Hard Disk Drive) by a CPU (Central Processing Unit) (not shown) By executing middleware such as an OS (Operating System) or software operating on the middleware, processing related to each function described later may be executed.

  Further, the hardware implementation and the software implementation may be combined as appropriate. In addition, the configuration is not limited to a configuration in which the entirety is mounted in one casing, and a configuration in which some functions are mounted in another casing and the casings are mutually connected by a communication cable or the like may be used. That is, the mounting form of the fuel reduction rate output system 1 is not particularly limited, and can be configured flexibly as appropriate according to the plant environment and the like.

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

<Calculation of fuel reduction rate>
As described above, the fuel reduction rate output system 1 according to the present embodiment has some kind of fuel reduction contribution to the boiler combustion control system 4 (or other system added to the boiler combustion control system 4). It is assumed that When energy saving is performed in response to such a fuel reduction contribution, in particular, when controllability is improved by conventional techniques as described in Patent Documents 1 and 2, the pressure of the main steam generated by the boiler 2 The fluctuation of becomes smaller. Thereby, the fluctuation | variation of the combustion state in the furnace of the boiler 2 and the state of the whole unit containing the steam turbine 3 for electric power generation becomes small, and fuel consumption is reduced as a result.

  In such a boiler combustion control system 4, the magnitude of the fluctuation of the state of the entire unit, that is, the magnitude of fluctuation of the main steam pressure can be considered in association with the fuel reduction rate. Therefore, in the fuel reduction rate output system 1 of the present embodiment, the estimated value of the fuel reduction rate is calculated by the following method.

  As shown in the figure, 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, within a predetermined time period (for example, within the past 60 minutes) recorded in the measured main vapor pressure PV and the main vapor pressure history 14 at regular intervals such as once per minute. Compare with the history of main vapor pressure. The main vapor pressure history 14 records at least the measurement value of the main vapor pressure over the past predetermined time (for example, 60 minutes) at a frequency equal to or higher than the predetermined interval (for example, 1 minute interval). It is assumed that

  The deviation determining unit 11 extracts a history of main steam pressure in the range of, for example, about ± 5% from the current measured main steam pressure PV from the main steam pressure history 14, and counts the number thereof. If this number is equal to or greater than a predetermined number (for example, more than half of all historical data in the extracted population (in other words, more than half of the above-mentioned fixed period)), It is judged that it is controlled in a stable state at a value similar to the measured main steam pressure PV of the above, and the history information of the extracted main steam pressure (hereinafter sometimes referred to as “control main steam pressure”) Is output to the standard deviation calculator 12.

The standard deviation calculation unit 12 obtains the standard deviation based on the input history of the control main vapor pressure and outputs it to the fuel reduction rate output unit 13. This standard deviation is, for example,
Standard deviation improvement rate = 100− (control standard deviation / standard deviation before correspondence × 100)
The standard deviation improvement rate (%) is calculated by the following formula. Here, the control standard deviation is the standard deviation of the history of the input control main steam pressure, and the standard deviation before correspondence is the standard deviation of the history of main steam pressure in the state before the fuel reduction contribution correspondence is made. It is. It should be noted that the standard deviation before response (that is, the control main vapor pressure in the state before the target fuel reduction contribution response is made), which is the basis for calculating the improvement rate, is, for example, before the target fuel reduction contribution response Obtain and record in advance. Alternatively, it may be set as a predetermined variable function so that the coefficient can be changed as appropriate.

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

  FIG. 2 is a diagram showing an example of the relationship between the improvement rate of the standard deviation of the main vapor pressure and the fuel reduction rate in the present embodiment. In the graph of FIG. 2, the horizontal axis (x axis) is the standard deviation improvement rate (%) of the main steam pressure, and the vertical axis (y axis) is the fuel reduction rate (%). On the other hand, a plot of actual results when various types of fuel reduction contribution responses are made is shown. As shown in FIG. 2, it can be seen that there is a correlation in which the fuel reduction rate increases as the improvement rate of the standard deviation of the main vapor pressure increases. This correlation can be formulated for each boiler 2 by linear approximation as illustrated (in the example of FIG. 2, “y = 0.0378x + 0.1604” shown in the figure). In the present embodiment, the fuel reduction rate output unit 13 calculates the estimated value of the fuel reduction rate by applying the standard deviation improvement rate input to the linearly approximated reference equation.

  In this embodiment, as shown in FIG. 1, the fuel reduction rate output unit 13 is configured to have one fuel reduction rate output unit 13. However, the fuel reduction rate output unit 13 is provided for each measured main vapor pressure PV (load band). It is good also as a structure which sets up and uses properly. Alternatively, a single fuel reduction rate output unit 13 may be configured to use a plurality of reference expressions indicating the relationship between the standard deviation improvement rate and the fuel reduction rate for each load band. Further, the above-described reference expression may be set as a predetermined variable function so that the coefficient can be changed as appropriate. In the present embodiment, an estimated value of the fuel reduction rate (%) is calculated and output. However, this is multiplied by the boiler input command value BID (the amount of fuel input to the boiler 2) to reduce the fuel. It may be output as a quantity.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to the one having all the configurations described. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of the above-described embodiment.

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

  Moreover, in each said figure, the control line and the information line have shown what is considered necessary for description, and do not necessarily show all the control lines and information lines on mounting. Actually, it may be considered that almost all the components are connected to each other.

  The present invention is applicable 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 boiler efficiency.

DESCRIPTION OF SYMBOLS 1 ... Fuel reduction rate output system, 2 ... Boiler, 3 ... Steam turbine, 4 ... Boiler combustion control system,
DESCRIPTION OF SYMBOLS 11 ... Deviation determination part, 12 ... Standard deviation calculation part, 13 ... Fuel reduction rate output part, 14 ... Main vapor pressure history, 15 ... Fuel reduction rate,
PV: Measurement main vapor pressure, PX: Main vapor pressure transmitter, MWD: Load requirement, BID: Boiler input command value

Claims (6)

A fuel reduction rate output system for calculating a fuel reduction rate related to fuel reduction applied to a boiler combustion control system that supplies fuel related to the amount of fuel input to the boiler calculated with respect to the required load amount to the boiler. And
The measured main steam pressure history, which is the 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 within a predetermined range. A deviation determination unit that outputs a history of main steam pressure at a control main steam pressure history;
A standard deviation calculating unit that calculates a standard deviation based on a history of the control main steam pressure output by the deviation determining unit;
A standard deviation improvement rate is calculated based on the standard deviation calculated by the standard deviation calculation unit, and the fuel reduction rate is calculated based on a reference expression indicating a relationship between the standard deviation improvement rate and the fuel reduction rate. A fuel reduction rate output system that outputs a fuel reduction rate output unit. The fuel reduction rate output system according to claim 1,
The fuel reduction rate output system in which the reference formula is set for each load band in the boiler. The fuel reduction rate output system according to claim 1 or 2,
A fuel reduction rate output system in which the reference equation is set as a predetermined variable function. The fuel reduction rate output system according to any one of claims 1 to 3,
A fuel reduction rate output system comprising a display unit for displaying the fuel reduction rate output by the fuel reduction rate output unit. Fuel in a fuel reduction rate output system that calculates a fuel reduction rate related to fuel reduction applied to a boiler combustion control system that supplies fuel related to the amount of fuel input to the boiler calculated with respect to the required load amount to the boiler Reduction rate output method,
A history recording step of recording a history of measured main steam pressure, which is a main steam pressure of the boiler, as a main steam pressure history;
A deviation determination step of calculating a deviation between the main steam pressure history and the measured main steam pressure, and outputting a history of the main steam pressure whose deviation is within a predetermined range as a history of the control main steam pressure;
A standard deviation calculating step of calculating a standard deviation based on a history of the control main steam pressure output by the deviation determining step;
A standard deviation improvement rate is calculated based on the standard deviation calculated in the standard deviation calculation step, and the fuel reduction rate is calculated based on a reference expression indicating a relationship between the standard deviation improvement rate and the fuel reduction rate. And a fuel reduction rate output step for outputting the fuel reduction rate. A computer as a fuel reduction rate output system for calculating a fuel reduction rate related to fuel reduction applied to a boiler combustion control system that supplies fuel related to the amount of fuel input to the boiler calculated with respect to the required load amount to the boiler A fuel reduction rate output program that
A history recording process for recording the history of the main steam pressure measured as the main steam pressure of the boiler as a 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 a history of the main steam pressure whose deviation is within a predetermined range as a history of the control main steam pressure;
A standard deviation calculation process for calculating a standard deviation based on a history of the control main steam pressure output by the deviation determination process;
A standard deviation improvement rate is calculated based on the standard deviation calculated by the standard deviation calculation process, and the fuel reduction rate is calculated based on a reference expression indicating a relationship between the standard deviation improvement rate and the fuel reduction rate. A fuel reduction rate output program that causes the computer to execute a fuel reduction rate output process that is output in the same manner.

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