AU2018280740B2

AU2018280740B2 - Fuel reduction rate output system, fuel reduction rate output method, and fuel reduction rate output program

Info

Publication number: AU2018280740B2
Application number: AU2018280740A
Authority: AU
Inventors: Daisuke KAMIHASHIRA; Nobuhiro KASHIMA; Yuji Okamura; Kenichiro SUTOH; Kazunori Taniguchi; Toru Yamashita
Original assignee: Idemitsu Kosan Co Ltd; Nippon Yusen KK; NYK Trading Corp
Current assignee: Idemitsu Kosan Co Ltd; Nippon Yusen KK; NYK Trading Corp
Priority date: 2017-06-09
Filing date: 2018-05-18
Publication date: 2023-05-25
Anticipated expiration: 2038-05-18
Also published as: KR20200030504A; WO2018225481A1; TW201903548A; CN110832251B; JP2019002574A; TWI682126B; JP6715800B2; MY203667A; CN110832251A; KR102469420B1; AU2018280740A1

Abstract

A fuel reduction rate output system that calculates a fuel reduction rate affecting a fuel reduction measure, which is applied to a boiler combustion control system, wherein the fuel reduction rate output system has: a deviation determination unit that records the history of measured main steam pressures as a main steam pressure history, that calculates the deviation between the main steam pressure history and the measured main steam pressures, and that outputs the history of the main steam pressure for which the deviation is within a prescribed range as a history of control main steam pressure; a standard deviation calculation unit that calculates a standard deviation on the basis of the history of control main steam pressure output by the deviation determination unit; and a fuel reduction rate output unit that calculates a standard deviation improvement rate on the basis of the standard deviation calculated by the standard deviation calculation unit and that calculates and outputs the fuel reduction rate on the basis of a reference equation indicating the relationship between the standard deviation improvement rate and the fuel reduction rate.

Description

SPECIFICATION TITLE OF THE INVENTION FUEL REDUCTIONRATE OUTPUT SYSTEM, FUEL REDUCTIONRATE OUTPUTMETHOD, AND FUEL REDUCTION RATE OUTPUT PROGRAM TECHNICAL FIELD

[0001]

The present invention relates to a technique to control

combustion of a boiler, and more specifically, the present invention

relates to a technique that is effective for applying 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 improvement of efficiency of a boiler.

BACKGROUND ART

[0002]

For example, in a case where a boiler facility is used to

acquire energy, fuel (solid fuel such as coal, liquid fuel, or gas

fuel) is supplied to a boiler (or a furnace) to burn, and its heat

is absorbed by a heat exchanger to cause steam to be generated,

thereby obtaining thermal energy. The generated steam is supplied

to a steamturbine tobe converted fromthe thermalenergy into rotary

motion, thereby being used for power generation by an electric

generator, for example. A fuel charging amount to the boiler is

determined by a fuel function FX. The fuel function FX is a

relational expression between a load demand (for example, power

generation demand MWD (Mega Watt Demand); hereinafter, referred to

also as a "load demand MWD") and the fuel charging amount to the

boiler (hereinafter, referred to also as a "boiler input command

value BID (Boiler Input Demand)").

[0003]

Here, variation in an operation state of the boiler, in

particular, variation in a main steam pressure may occur due to an

influence by factors related to a boiler facility, for example, a

fuel property by fuel switching or the like or a change in heat

quantity, furnace grime, soot blower, air and water temperature,

or the like. Therefore, a control in which fuel related to a fuel

charging amount found by the fuel function FX is supplied to the

boiler, the generated main steam pressure is measured, a feedback

correction amount is found by a PID

(Proportional-Integral-Differential) control on the basis of a

difference between this and a main steam pressure set in advance,

and the fuel charging amount to the boiler is corrected by adding

this to a load demand has been executed generally.

[0004]

As a technique related to this, for example, Japanese Patent

No. 4,522,326 (Patent document 1) describes that a plurality of

ratios or differences between values before and after feedback

correction is executed are recorded while updating them in turn,

a fuel correction factor is found from the plurality of recorded

values, and a value after the feedback correction is corrected by

this fuel correction factor. This makes it possible to correct a

fuel charging amount into proper one in view of a change in thermal

efficiency of a boiler due to an influence of factors.

[0005]

Moreover, for example, Japanese Patent No. 4791269 (Patent

Document 2) describes that, in a mixed combustion boiler for plural

kinds of fuels, by subdividing a fuel correction factor for

correcting a value after feedback correction into three elements,

a fuel charging amount to the boiler is corrected so as to address

a difference ofunit heat quantity of fuel and a difference ofboiler

thermal efficiency with a change in a mixed fuel combustion ratio.

RELATED ART DOCUMENTS PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent No. 4522326

Patent Document 2: Japanese Patent No. 4791269

SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0007]

For example, according to the conventional technology of

Patent document 1 or 2, by always comparing and measuring values

of a load demand MWD before and after feedback correction (or other

control values) with respect to a change in thermal efficiency of

the boiler due to an influence ofthe factors, this canbe determined,

and a value of a correction factor for further correcting and

optimizing the value after the feedback correction on the basis of

a determination result can be acquired by self-learning.

[0008]

It is possible to improve efficiency of the boiler by

optimizing a control using these correction factors. However, in

order to grasp a degree ofimprovement ofthe efficiency ofthe boiler,

conventionally, it has been required to carry out a performance test

to measure it actually. Specifically, for example, activation and

non-activation of a control function related to energy saving is

switched, each of a fuel consumption amount and a generation amount

of steam is compared between an activation period and a

non-activation period, and a fuel reduction rate is calculated.

However, an approach requiring such aperformance test is roundabout,

and the fuel reduction rate cannot be estimated in real time during

an operation.

[0009]

It is thus an object of the present invention to provide a

fuel reduction rate output system, a fuel reduction rate output method, and a fuel reduction rate output program capable of outputting a fuel reduction rate obtained by improvement in control performance of a boiler, that is, an energy-saving ratio in real time.

[0010]

The foregoing and other objects, and new features of the

present invention will become more apparent from description of the

present specification and the appending drawings.

MEANS FOR SOLVING THE PROBLEM

[0011]

An outline of representative invention of the present

invention disclosed in the present application and the like will

briefly be explained as follows.

[0012]

A fuel reduction rate output system according to a

representative embodiment of the present invention is a fuel

reduction rate output system configured to calculate a fuel

reduction rate related to fuel reduction contributing measures, the

fuel reduction contributing measures being applied to a boiler

combustion control system, the boiler combustion control system

supplying fuel related to a fuel charging amount for a boiler

calculated with respect to a load demand to the boiler. The fuel

reduction rate output systemincludes: a deviation determiningunit

configured to record a history of a measured main steam pressure

as a main steam pressure history, calculate a deviation between the

main steam pressure history and the measured main steam pressure,

and output a history of a main steam pressure when the deviation

is within a predetermined range as a history of a controlled main

steampressure, the measuredmain steampressurebeingthe main steam

pressure thus measured of the boiler; a standard deviation

calculating unit configured to calculate a standard deviation on

a basis of the history of the controlled main steam pressure outputted by the deviation determining unit; and a fuel reduction rate output unit configured to calculate an improvement rate of the standard deviation on a basis of the standard deviation calculated by the standard deviation calculating unit, calculate and output a fuel reduction rate on a basis of a criteria expression, the criteria expression indicating a relationship between the improvement rate of the standard deviation and the fuel reduction rate.

[0013]

Further, in addition to the fuelreduction rate output system

as described above, the present invention can also be applied to

a fuel reduction rate output method and a fuel reduction rate output

program for causing a computer to operate as the fuel reduction rate

output system as described above.

EFFECTS OF THE INVENTION

[0014]

Effects obtained by representative invention of the present

invention disclosed in the present application will briefly be

explained as follows.

[0015]

Namely, according to the representative embodiment of the

present invention, it becomes possible to output a fuel reduction

rate obtained by improvement of controllability of a boiler, that

is, an energy-saving ratio in real time.

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0016]

FIG. 1 is a view illustrating an outline of a configuration

example of a fuel reduction rate output system according to one

embodiment of the present invention.

FIG. 2 is a view illustrating an example of a relationship

between an improvement rate of a standard deviation of a main steam pressure and a fuel reduction rate according to one embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENT

[0017]

Hereinafter, an embodiment of the present invention will be

described in detail with reference to the drawings. Note that in

allofthe drawings for explainingthe embodiment, the same reference

numeral is generally assigned to the same unit, and its repeated

explanation will be omitted. On the other hand, a component has

been explained in a certain drawing while applying a reference

numeral thereto is not illustrated again when another drawing is

to be explained, but the element may be referred to by applying the

same reference numeral thereto.

[0018]

FIG. 1 is a view illustrating an outline of a configuration

example of a fuel reduction rate output system according to one

embodiment of the present invention. In FIG. 1, a control for a

boiler 2 is executed by an existingboiler combustion control system

4. The boiler combustion control system 4 uses a load demand MWD

as an input, and determines a boiler input command value BID, which

is a fuel charging amount for the boiler, by a fuel function (not

illustrated in the drawings). In a case where such measures that

fuel reduction is expected (hereinafter, correctively referred to

also as "fuel reduction contributing measures") is made, for example,

in a case where this boiler combustion control system 4 is newly

updated or additionally installed or in a case where measures to

improve controllability as indicated in Patent Documents 1 and 2

is made, as will be described later, a fuel reduction rate output

system 1 calculates and outputs a fuel reduction rate 15 in real

time on the basis of a standard deviation of a main steam pressure of the boiler 2.

[0019]

Note that 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 a separate system. However, it may be configured

to be integrated as a part of the boiler combustion control system

4. 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. However, it maybe configured so as to include a display

unit configured to output the fuel reduction rate 15 by being

displayed on a display (not illustrated in the drawings) or being

printed by a printer in a predetermined format or layout. By

including such a display unit, it is possible to grasp the fuel

reduction rate 15 (or a fuel reduction amount) instantaneously.

[0020]

The fuel reduction rate output system 1 may be configured,

for example, as an apparatus implemented by hardware that consists

of a semiconductor circuit, a microcomputer, or the like (not

illustrated in the drawings), which executes processes related to

respective functions (willbe described later). Alternatively, the

fuel reduction rate output system 1 may be configured by

general-purpose server equipment or a virtual server built on cloud

computing service, and may execute processes related to the

respective functions (will be described later) by executing

middleware such as an OS (Operating System), which is developed onto

a memory from a recording device such as a HDD (Hard Disk Drive)

by aCPU (CentralProcessingUnit) (not illustratedin the drawings),

or software that operates thereon.

[0021]

Further, the fuel reduction rate output system 1 may be

configured by appropriately combining implementation by the

hardware and implementation by the software. Further, it is not limited to a configuration in which the whole is implemented in one housing. It may be configured so that a part of the functions is implemented in another housing and these housings are mutually connected to each other by a communication cable or the like. Namely, the embodiment of the fuel reduction rate output system 1 is not limited particularly, and can be appropriately configured flexibly in accordance with an environment or the like of the plant.

[0022]

As illustrated in FIG. 1, the fuel reduction rate output

system 1 includes, for example, respective units such as a deviation

determining unit 11, a standard deviation calculating unit 12, and

a fuel reduction rate output unit 13, each of which is implemented

by hardware or software. Further, the fuel reduction rate output

system 1 has data such as a main steam pressure history 14 and the

like, each of which is implemented as a file, a table, or a database

recorded in the memory or the HDD.

[0023]

As described above, in the fuel reduction rate output system

1 according to the present embodiment, it is assumed that any fuel

reduction contributing measures are made to the boiler combustion

control system 4 (or by another system that is to be added to the

boiler combustion control system 4, or the like). In a case where

energy saving is carried out by such fuel reduction contributing

measures, in particular, in a case where improvement of

controllability by the conventional technologies as described in

Patent Documents 1 and 2 is carried out, a variation in the main

steam pressure generated by the boiler 2 is made smaller. Thus,

a variation in a combustion state in a furnace of the boiler 2 or

a state of the whole unit including a steam turbine 3 for power

generation is made smaller, and as a result, a fuel consumption

amount is reduced.

[0024]

In suchaboiler combustion controlsystem4, it canbe thought

that a magnitude of the variation in the state of the whole unit,

that is, a magnitude of the variation in the main steam pressure

is associated with the fuel reduction rate. Therefore, in the fuel

reduction rate output system 1 according to the present embodiment,

an estimated value of the fuel reduction rate is calculated by the

following method.

[0025]

As illustrated in FIG. 1, a current measured main steam

pressure PV is inputted to the deviation determining unit 11 of the

fuel reduction rate output system 1 from a main steam pressure

transmitter PX. The deviation determining unit 11 compares, for

example, in a fixed interval such as once per minute, the measured

main steam pressure PV with a history of the main steam pressure

within a past fixed time (for example, within the past 60 minutes),

which is recorded in the main steam pressure history 14. Note that

at least measurement values of the main steam pressure over the past

of the fixed time described above (for example, for 60 minutes) or

longer is recorded in the main steam pressure history 14 at a

frequency of the fixed interval described above (for example,

one-minute interval) or higher.

[0026]

The deviation determining unit 11 extracts a history of the

main steam pressure, which is in a range of about ±5% of a current

the measuredmain steampressure PV, for example, fromthe main steam

pressure history 14, and counts the number of data. In a case where

this number is equal to or more than a predetermined number (for

example, a half or more of all of the history data that are extracted

as a population (in other words, a half period of the fixed period

described above or longer)), it is determined that the main steam

pressure is controlled in a stabilized state at almost the same value as the current measured main steam pressure PV, and outputs information on the history of the extracted main steam pressure

(hereinafter, referred to also as a "controlled main steam

pressure") to the standard deviation calculating unit 12.

[0027]

The standard deviation calculating unit 12 calculates the

standard deviation on the basis of the inputted history of the

controlled main steam pressure, and outputs it to the fuel reduction

rate output unit 13. This standard deviation is calculated by the

following expression as an improvement rate of the standard

deviation (%), for example:

(improvement rate ofstandard deviation) = 100 -((controlled

standard deviation) / (standard deviation before measures) x 100)).

Here, the controlled standard deviation is a standard deviation of

the inputted history of the controlled main steam pressure, and the

standard deviation before measures is a standard deviation of a

history of the main steam pressure in a state before the fuel

reduction contributing measures are made. Note that the standard

deviation before measures that become the basis of calculation of

the improvement rate (that is, the controlled main steam pressure

in the state before target fuel reduction contributing measures are

made) is obtained and recorded in advance before the target fuel

reduction contributing measures are made, for example.

Alternatively, it may be set as a predetermined variable function,

and its coefficient may be allowed to be changed appropriately.

[0028]

The fuelreduction rate output unit 13 calculates and outputs

the estimated value of the fuel reduction rate on the basis of a

predetermined mathematical expression from the inputted

improvement rate of the standard deviation described above.

[0029]

FIG. 2 is a view illustrating an example of a relationship between the improvement rate of the standard deviation of the main steam pressure and the fuel reduction rate according to the present embodiment. A graph of FIG. 2 uses the improvement rate of the standard deviation (%) of the main steam pressure as a horizontal axis (x-axis) and the fuel reduction rate (%) as a vertical axis

(y-axis), and indicates a plot of actual results when various kinds

of fuel reduction contributing measures were respectively made for

the boilers 2 installed to various kinds of plants are plotted. As

illustrated in FIG. 2, it can be seen that there is a correlation

that the greater the improvement rate of the standard deviation of

the main steam pressure is, the greater the fuel reduction rate

becomes. Then, this correlation can be formulated for each of the

boilers 2 by linear approximation as illustrated in FIG. 2 (in the

example of FIG. 2, "y = 0.0378x + 0.1604" indicated in FIG. 2). In

the present embodiment, by applying the inputted improvement rate

of the standard deviation to this criteria expression subjected to

the linear approximation, the fuel reduction rate output unit 13

calculates the estimated value of the fuel reduction rate.

[0030] Note that, in the present embodiment, as illustrated in FIG.

1, it is configured so as to have one fuel reduction rate output

unit 13. However, it may be configured so that a plurality of fuel

reduction rate output units 13 is respectively provided and used

in accordance with degrees (load bands) of the measured main steam

pressure PV and. Alternatively, it may be configured so that a

plurality of criteria expressions each indicating a relationship

between the improvement rate of the standard deviation described

above and the fuel reduction rate is respectively provided and used

in accordance with the load bands by one fuel reduction rate output

unit 13. Further, the criteria expression described above may be

set as a predetermined variable function, and its coefficient may

be allowed to be changed appropriately. Further, in the present embodiment, the estimated value of the fuel reduction rate (%) is calculated and outputted. However, by multiplying this by the boiler input command value BID (the fuel charging amount to the boiler 2), the multiplied one may be outputted as the fuel reduction amount.

[0031]

As described above, the invention made by inventors of the

present application has been described specifically on the basis

of the embodiment. However, the present invention is not limited

to the embodiment described above, and it goes without saying that

the present invention may be modified into various forms without

departing from the substance thereof. For example, the embodiment

described above has been explained in detail for explaining the

present invention clearly. The present invention is not

necessarily limited to one that includes all configurations that

have been explained. Further, a part of the configuration of the

embodiment can be added with the other configuration, deleted or

replaced thereby.

[0032]

Further, a part or all of the respective configuration

described above, the functions, processing units, and processing

means may be realized by hardware that is designed by an integrated

circuit, for example. Further, the respective configuration

described above and the functions may be realized by software so

that a processor interprets programs realizing the respective

functions and execute the interpreted programs. Information on

programs, tables, and files, which realize the respective functions,

can be placed 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.

[0033]

Further, in each of the drawings described above, control lines and information lines are illustrated so long as they are thought to be necessary for explanation. All of the control lines and the information lines are not necessarily illustrated on the implementation. In fact, it may be considered that almost all of the components are connected to each other.

INDUSTRIAL APPLICABILITY

[0034]

The present invention is usable for a fuel reduction rate

output system, a fuel reduction rate output method, and a fuel

reduction rate output program each of which calculates a fuel

reduction rate obtained by improvement of efficiency of a boiler.

REFERENCE SINGS LIST

[0035]

1 ... fuel reduction rate output system, 2 ... boiler, 3 ... steam turbine,

4 ... boiler combustion control system, 11 ... deviation determining

unit, 12 ... standard deviation calculating unit, 13 ... the fuel

reduction rate output unit, 14 ... main steam pressure history, 15

... fuel reduction rate, PV ... measured main steam pressure, PX ... main

steam pressure transmitter, MWD ... load demand, BID ... boiler input

command value

Claims

1. A fuel reduction rate output system configured to calculate

a fuel reduction rate related to fuel reduction contributing

measures, the fuel reduction contributing measures being applied

to a boiler combustion control system, the boiler combustion control

system supplying fuel related to a fuel charging amount for a boiler

calculated with respect to a load demand to the boiler, the fuel

reduction rate output system comprising:

a deviation determining unit configured to record a history

of a measured main steam pressure as a main steam pressure history,

calculate a deviation between the main steam pressure history and

the measured main steam pressure, and output a history of a main

steam pressure when the deviation is within a predetermined range

as a history of a controlled main steam pressure, the measured main

steam pressure being the main steam pressure thus measured of the

boiler;

a standard deviation calculating unit configured to

calculate a standard deviation on a basis of the history of the

controlled main steam pressure outputted by the deviation

determining unit; and

a fuel reduction rate output unit configured to calculate

an improvement rate of the standard deviation on a basis of the

standard deviation calculatedby the standard deviation calculating

unit, calculate and output a fuel reduction rate on a basis of a

criteria expression, the criteria expression indicating a

relationship between the improvement rate of the standard deviation

and the fuel reduction rate.

2. The fuel reduction rate output system according to claim 1,

wherein the criteria expression is set for each load bands

on the boiler.

3. The fuel reduction rate output system according to claim 1

or 2,

wherein the criteria expression is set as a predetermined

variable function.

4. The fuel reduction rate output system according to any one

of claims 1 to 3, further comprising:

a display unit configured to display the fuel reduction rate

outputted by the fuel reduction rate output unit.

5. A fuel reduction rate output method in a fuel reduction rate

output system configured to calculate a fuel reduction rate related

to fuel reduction contributing measures, the fuel reduction

contributing measures being applied to a boiler combustion control

system, the boiler combustion control system supplying fuel related

to a fuel charging amount for a boiler calculated with respect to

a load demand to the boiler, the fuel reduction rate output method

comprising:

a history recording step of recording a history of a measured

main steam pressure as a main steam pressure history, the measured

main steam pressure being the main steam pressure thus measured of

the boiler;

a deviation determining step of calculating a deviation

between the main steam pressure history and the measured main steam

pressure, and outputting a history of a main steam pressure when

the deviation is within a predetermined range as a history of a

controlled main steam pressure;

a standard deviation calculating step of calculating a

standard deviation on a basis of the history of the controlled main

steam pressure outputted by the deviation determining step; and

a fuel reduction rate outputting step of calculating an improvement rate of the standard deviation on abasis of the standard deviation calculated by the standard deviation calculating step, calculating and outputting a fuel reduction rate on a basis of a criteria expression, the criteria expression indicating a relationship between the improvement rate of the standard deviation and the fuel reduction rate.

6. A fuel reduction rate output program for causing a computer

to serve as a fuel reduction rate output system configured to

calculate a fuel reduction rate related to fuel reduction

contributing measures, the fuel reduction contributing measures

being applied to a boiler combustion control system, the boiler

combustion control system supplying fuel related to a fuel charging

amount for a boiler calculated with respect to a load demand to the

boiler, the fuel reduction rate output program causing the computer

to execute:

a history recording process to record a history of a measured

main steam pressure as a main steam pressure history, the measured

main steam pressure being the main steam pressure thus measured of

the boiler;

a deviation determining process to calculate a deviation

between the main steam pressure history and the measured main steam

pressure, and output a history of a main steam pressure when the

deviation is within a predetermined range as a history of a

controlled main steam pressure;

a standard deviation calculating process to calculate a

standard deviation on a basis of the history of the controlled main

steam pressure outputted by the deviation determining process; and

a fuel reduction rate outputting process to calculate an

improvement rate of the standard deviation on abasis of the standard

deviation calculated by the standard deviation calculatingprocess,

calculate and output a fuel reduction rate on a basis of a criteria expression, the criteria expression indicating a relationship between the improvement rate of the standard deviation and the fuel reduction rate.