CN103674333A - Real-time identification method for fired coal lower heating value of coal-fired power plant - Google Patents

Abstract

The invention provides a real-time identification method for a fired coal lower heating value of a coal-fired power plant. The real-time identification method includes the steps of (1) obtaining boiler structure parameters according to a boiler operation design discipline, and reading an operation condition measurement point real-time value at the given moment from a real-time database of a DSC, (2) calculating the specific enthalpy and the density of working media and the specific heat and the density of smoke based on a working medium physical property parameter base and a smoke physical property parameter base, (3) correcting main steam flow masses based on a relation model of main steam adjustment door opening degrees and the main steam flow masses, (4) respectively calculating corresponding energy output of various parts on the boiler side and total energy output at the given moment according to a boiler-side complete-flow-path mechanism model, (5) building a transfer function model between coal feeding flow masses of a coal feeder and the fired coal flow masses, and (6) building a transfer function model between the fired coal flow masses and the total energy output. The real-time identification method is used for on-line identification on the fired coal lower heating value, and has the application potential of combustion and coal blending optimization.

Description

A kind of coal fired power plant enters the real-time identification method of stove coal net calorific value

Technical field

What the present invention relates to thermal power generation control field a kind ofly enters stove coal net calorific value real-time identification method, particularly, relates to and a kind ofly based on station boiler side mechanism model and DCS real time data, enters stove coal net calorific value real-time identification method.

Background technology

Coal-fired firepower power station is the main body of China's power industry, is also the major fields of energy-saving and emission-reduction.Due to the diversification of China's coal mining, transportation, coal price, most of power plant all faces that this affects the bottleneck problem of whole process safe and highly efficient operation into stove ature of coal frequent fluctuation.An important indicator weighing ature of coal is net calorific value, and net calorific value is defined as the heat that the coal perfect combustion of unit mass can produce.Thereby the change of net calorific value directly affects fire coal breaks full-range energy equilibrium in the thermal value of burner hearth.If thermal value raises and do not subtract in time coal, the input of boiler side gross energy, higher than specified output, causes unit generated energy coal consumption in short-term to be risen; If thermal value declines and it is coal-fired not supplement in time, will directly cause unit short-time rating decline and load tracking precise decreasing.If enter stove coal net calorific value, can measure in real time, for coal blending workshop section, being equivalent to has had feedback signal, can be used for instructing the optimization of coal blending; For boiler-turbine coordinated, just can check in time coal, implement compensation and control.

Yet the sampling analysis cycle of China's most of coal fired power plant ature of coal off-line assay value reaches 6-8 hour, can not be as the foundation of real-time control (as coal-supplying amount feedforward compensation).Ature of coal often will be waited until after changing could be by " perception " when main steam pressure occurs obviously to change, by boiler master system, regulate a wind flow to increase/to reduce furnace coal weight subsequently, slowly, the transient process 15-30 of reaching minute consuming time is stabilized in whole interference in said process response.Like this, the period of change that enters stove coal net calorific value if actual is hour level, and whole production just may, in continued jitters state, have a strong impact on economy and steadily security that electricity power enterprise produces.In view of the above Subcritical Units of domestic 300MW, bear all the year round to some extent the puzzlement of ature of coal frequent variations, be badly in need of the support into stove coal net calorific value Fast Identification technology, to improve control quality.

Through the retrieval to prior art, Liu Fuguo (Liu Fuguo. the identification real time monitoring of fuel coal of power station boiler ultimate analysis and thermal value. Proceedings of the CSEE .25 (6), 139-144,2005) coal-fired ultimate analysis and the thermal value discrimination method based on dynamic element balance proposed, and being successfully applied to 300MW unit, net calorific value precision of prediction is higher.But, the method need to discharge fume composition real-time measurement and need to carry out ash content correction.U.S.'s thermoelectricity (Thermo Electron, existing name Thermo Fisher Scientific Inc.) based on rapid neutron activation analysis (PGNAA-Prompt Gamma Neutron Activation Analysis), developed coal supply elemental analyser, by software, calculate real-time net calorific value, but it relates to application and the management of radioactive source, this product price and long-time maintenance cost are higher in addition, are widely applied far away at home.

Summary of the invention

For defect of the prior art, the object of this invention is to provide a kind of power station and enter stove coal net calorific value real-time identification method, the method makes full use of DCS control system real time data, the real-time simulation of bonded boiler side whole process mechanism model builds dynamic mass and energy balance relations, and then obtains into stove coal net calorific value; Utilize net calorific value real-time identification value to compensate control to entering stove coal mass rate, obviously contribute to the safety and steady of fired power generating unit to produce and thermal efficiency optimization.

For realizing above object, the invention provides a kind of power station and enter stove coal net calorific value real-time identification method, the method comprises the following steps:

Step 1, according to boiler operatiopn design discipline, obtain the following structural parameters of boiler: heat exchanger tube at different levels are along total length, sectional area distribution, the heat interchanger metallic walls quality of Working fluid flow direction; From the real-time data base of DCS control system, read the operation condition real time data under given time, specifically comprise: exhaust gas temperature, volumetric flow rate, boiler load and the environment atmospheric pressure at the Temperature of Working at drum pressure, main steam mass rate, reheat heat steam mass flow, economizer exit feed-water quality flow, heat interchanger measuring points at different levels place and pressure, heat interchanger metallic walls temperature, flue outlet induced draft fan place;

Step 2, according to working medium physical parameter storehouse and drum pressure, calculate this given time water drum outlet saturated vapour specific enthalpy and density, temperature, the pressure of establishing working medium between the adjacent crucial measuring point of heat interchanger at different levels are linear distribution simultaneously, and by fixing discretize length, heat interchanger at different levels are divided into series of discrete infinitesimal, calculate working medium specific enthalpy and the density of each infinitesimal; According to flue gas physical parameter storehouse and exit gas temperature, pressure, atmospheric pressure, calculate specific heat and the density of exit gas under this given time;

Step 3, the relational model based on main vapour pitch aperture and main steam mass rate, according to real-time main vapour pitch aperture correction main steam mass rate, particularly: based on main vapour pitch aperture and main steam mass rate characteristic, the DCS measured data of pitch group and the dynamic perfromance of over-temperature channel heat interchanger at different levels and drum, revise in time main steam maskantflowmeter observation value, thereby obtain the main steam mass rate matching with actual furnace coal weight and feedwater flow;

Step 4, according to boiler side whole process mechanism model, calculate respectively the output of corresponding boiler side each several part energy and gross energy and export, wherein enter the gross energy Q that the perfect combustion of stove coal produces and transmits _sumwhereabouts is divided into two parts: first is that boiler system is effectively utilized heat Q ₁, can further be decomposed into water-cooling wall caloric receptivity Q _slbwith heat interchanger at different levels, comprise superheaters at different levels, reheater, economizer heat exchange amount Q _heatex; Second portion is thermal loss, can further be decomposed into heat loss due to exhaust gas energy Q ₂, heat loss due to unburned gas energy Q ₃, heat loss due to combustibles in refuse energy Q ₄, boiler radiation loss energy Q ₅, heat loss due to sensible heat in slag's energy Q ₆; Boiler radiation loss energy Q ₅in gross energy, proportion is q ₅, q ₅by experimental formula, be easy to obtain, therefore enter the gross energy Q that the perfect combustion of stove coal produces and transmits _sumcan be expressed as:

Q _sum=(Q _heatex+Q _slb+Q ₂+Q ₃+Q ₄+Q ₆)/(1-q ₅) (1)

Step 5, set up feeder coal supply mass rate and enter the transfer function model between stove coal mass rate, obtain into stove coal mass rate;

Step 6, fire coal is entered to stove to take main steam, be between main energy output that phase relation is decomposed into coal dust and to working medium, transmit two processes at stove chamber inner combustion and heating power, and then set up the phase relation transfer function model between the output of stove coal mass rate and gross energy, by parameter identification, obtains with gross energy under this given time and export corresponding enter stove coal mass rate and net calorific value.

Preferably, in step 3, described main vapour pitch aperture and main steam mass rate characteristic, refer to the sectional type nonlinear function that main vapour pitch aperture is corresponding with main steam mass rate.Described correction main steam mass rate D _msmethod be:

$D_{\mathrm{ms}}=\underset{n=1}{\overset{5}{\mathrm{\Σ}}}\frac{\mathrm{\αf}\left(L_n\right)p_0}{\sqrt{T_0}}---\left(2\right)$

In formula, α is model parameter, f (﹒) represent aperture-mass rate characteristic of main vapour pitch, L _nrepresent revised main vapour pitch aperture, p ₀represent main steam pressure, T ₀represent main steam temperature;

Wherein:

L _n(k)=ΔL _n(k)+L _n0 (3)

$\frac{\mathrm{\Δ}{L}_n\left(s\right)}{{\mathrm{\ΔL}}_{\mathrm{ms}}\left(s\right)}=\frac{1}{1+\mathrm{Ts}}---\left(4\right)$

The difference form of formula (4) is:

${\mathrm{\ΔL}}_n\left(k\right)={\mathrm{\ΔL}}_n(k-1)\·e^{-\frac{\mathrm{\Δt}}{T}}+{\mathrm{\ΔL}}_{\mathrm{ms}}(k-1)\·(1-e^{-\frac{\mathrm{\Δt}}{T}})---\left(5\right)$

In formula, Δ L _msmain vapour pitch aperture increment for Real-time Feedback; Δ L _nrepresent revised main vapour pitch aperture increment; L _n0represent the main vapour pitch aperture before working conditions change; S represents Laplace operator; T represents the equivalent time constant of main steam pressure control loop and pulverized coal preparation system; Δ t is the sampling period; K is current given time, and k-1 is previous moment.

Preferably, in step 4, described boiler side whole process mechanism model comprises: water-cooling wall caloric receptivity computation model, at different levels overheated/reheater heat exchange amount computation model, economizer heat exchange amount computation model, thermal loss computation model; Particularly:

Described water-cooling wall caloric receptivity computation model, calculates by setting up energy and the dynamic mechanism model of quality of the whole boiler circuit of drum, downtake, water-cooling wall composition;

Described at different levels overheated/reheater heat exchange amount computation model, be establish at different levels overheated/between the adjacent measuring point of heat exchanger, temperature, the pressure of working medium are linear distribution again, and divide infinitesimal with fixing discretize length pipeline section, according to quality, energy dynamics balance equation, try to achieve at different levels overheated/heat exchanger heat exchange amount again;

Described economizer heat exchange amount computation model, because water in economizer is liquid, compressibility is very little, and energy can be accumulated hardly, therefore adopt energy homeostasis to account model, calculates;

Described thermal loss computation model, for calculating each several part thermal loss, model adopts experimental formula.

More preferably, in step 4, described at different levels overheated/heat exchanger heat exchange amount computation model is again:

The dynamic balance equation of quality:

$\mathrm{dD}=D\left(k\right)-D(k-1)=\underset{i=1}{\overset{L/0.1}{\mathrm{\Σ}}}{\mathrm{\ρ}}_i\left(k\right)A_i\·0.1-\underset{i=1}{\overset{L/0.1}{\mathrm{\Σ}}}{\mathrm{\ρ}}_i(k-1)A_i\·0.1---\left(6\right)$

$D_{\mathrm{in}}=\frac{\mathrm{dD}}{\mathrm{dt}}+D_{\mathrm{out}}---\left(7\right)$

In formula, D is overheated/working medium total mass flow rate in heat exchanger system again, ρ _ifor overheated/density of working medium in passage of heat i discrete infinitesimal again, A _ifor the overheated/equivalent circulation area of passage of heat i discrete infinitesimal again, D _in, D _outbe respectively overheated/again passage of heat entrance, outlet steam mass flow, dt is the differential to time t.

Energy dynamics balance equation:

$\begin{array}{c}\mathrm{dE}=E\left(k\right)-E(k-1)=\underset{i=1}{\overset{L/0.1}{\mathrm{\Σ}}}{\mathrm{\ρ}}_i\left(k\right)h_i\left(k\right)A_i\·0.1-\underset{i=1}{\overset{L/0.1}{\mathrm{\Σ}}}{\mathrm{\ρ}}_i(k-1)h_i(k-1)A\left(i\right)\·0.1\\ +c_{\mathrm{metal}}{M}_{\mathrm{metal}}\·{\mathrm{dT}}_{\mathrm{metal}}\end{array}---\left(8\right)$

$Q=\frac{\mathrm{dE}}{\mathrm{dt}}+D_{\mathrm{out}}{h}_{\mathrm{out}}-D_{\mathrm{in}}{h}_{\mathrm{in}}---\left(9\right)$

In formula, E is overheated/passage of heat working medium gross energy again, h _ifor overheated/specific enthalpy of working medium in passage of heat i discrete infinitesimal again, c _metal, M _metalwith Δ T _metalfor overheated/specific heat, gross mass and metallic walls temperature increment of passage of heat metallic walls again, Q is overheated/passage of heat working medium obtains from flue gas again energy, h _in, h _outbe respectively overheated/again passage of heat entrance, outlet specific steam enthalpy.

More preferably, in step 4, described economizer heat exchange amount computation model can obtain by energy balance

Q _sm=D _fw·(h' _out-h _i' _n) (10)

In formula, D _fwfor feed-water quality flow, h ' _inand h ' _outbe respectively economizer entrance feedwater specific enthalpy and economizer exit feedwater specific enthalpy.

More preferably, in step 4, described thermal loss computation model, wherein each several part thermal loss adopts experimental formula to calculate, particularly:

Q ₂=K ₁(Q _py-Ql _f) (11)

Q ₃=0 (12)

Q ₄=Q _cc·(G _fh·C _fh+G _lz·C _lz) (13)

${\mathrm{<figure-callout\; id="5"\; label="q"\; filenames="HDA0000440002890000011.png"\; state="\{\{state\}\}">q</figure-callout>}}_5=5.82\&CenterDot;{\left(D_e\right)}^{-0.38}\&CenterDot;\frac{D_e}{D}---\left(14\right)$

Q ₆=c _fh·G _fh·t _fh+c _lz·G _lz·t _lz (15)

In formula: K ₁into the imperfect combustion modified value of stove coal solid, Q _pysmoke evacuation energy, Ql _fcold air energy, Q _ccthe net calorific value that represents carbon, Q _cc=32.7MJ/kg, G _fh, G _lzrespectively the mass rate of flying dust and slag, C _lzthe carbon content of slag, C _fhunburned carbon in flue dust, D _ebe boiler volume, determine evaporation capacity, D is actual evaporation, equates c with main steam mass rate _fh, c _lzrespectively the specific heat capacity of flying dust and slag, t _fh, t _lzit is respectively the temperature of flying dust and slag;

Above-mentioned related parameter obtains by following formula:

K ₁=1-q ₄ (16)

q ₄=A _ad·A _fh·C _fh/F _cad (17)

Q _py=c _py·ρ _py·V _py·(t _py+273.15) (18)

Ql _f=cl _f·ρl _f·Vl _f·(tl _f+273.15) (19)

c _fh=0.71+0.000502·t _fh (20)

c _lz=0.71+0.000502·t _lz (21)

In formula, q ₄into stove coal solid-unburning hot loss number percent, A _adinto stove ash content of coal content, A _fhthe fly ash content in ash content, F _cadbe that c is the specific heats of gases into stove coal fixed carbon content, ρ is gas density, and V is gas flow, and t is gas temperature, and subscript py and lf represent respectively smoke evacuation and cold air.

Preferably, in step 5, described feeder coal supply mass rate and the transfer function model entering between stove coal mass rate adopt first order inertial loop model to characterize:

$\frac{D_{\mathrm{coal}}\left(s\right)}{D_{\mathrm{belt}}\left(s\right)}=\frac{1}{1+\mathrm{Ts}}---\left(22\right)$

Turning to difference form can obtain:

$D_{\mathrm{coal}}\left(k\right)=D_{\mathrm{coal}}(k-1)\&CenterDot;e^{-\frac{\mathrm{\&Delta;t}}{T}}+D_{\mathrm{belt}}(k-1)\&CenterDot;(1-e^{-\frac{\mathrm{\&Delta;t}}{T}})---\left(23\right)$

In formula, D _coalrepresent into stove coal mass rate, D _beltrepresent feeder coal supply mass rate, T represents coal pulverizer closed-loop control link and grinds the total equivalent time constant of link.

Preferably, in step 6, the described phase relation transfer function model entering between stove coal mass rate and gross energy output, refers to that adopting respectively first order inertial loop to characterize into stove coal transmits two processes to working medium, the order transfer function model finally obtaining at stove chamber inner combustion and heating power:

$\frac{Q_{\mathrm{sum}}\left(s\right)}{D_{\mathrm{coal}}\left(s\right)}=\frac{Q_{\mathrm{furnace}}\left(s\right)}{D_{\mathrm{coal}}\left(s\right)}\&CenterDot;\frac{Q_{\mathrm{sum}}\left(s\right)}{Q_{\mathrm{furnace}}}=\frac{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HDA0000440002890000011.png"\; state="\{\{state\}\}">K</figure-callout>}}{1+T_{1}s}\&CenterDot;\frac{1}{1+T_2\text{s}}---\left(24\right)$

In formula, Q _furnacerepresent to release energy at hearth combustion into stove coal, Q _sumthe summation that represents the output of boiler side whole process each several part energy, K is amplification coefficient, its physical significance is for entering stove coal net calorific value, T ₁for entering the time constant of stove coal combustion process, T ₂for the equivalent time constant of heating power to refrigerant heat transfer process.

Preferably, in step 6, the described phase relation transfer function model entering between stove coal mass rate and gross energy output carried out to the difference equation model that discretize obtains be:

$Q_{\mathrm{furnace}}\left(k\right)=Q_{\mathrm{furnace}}(k-1)\&CenterDot;e^{-\frac{\mathrm{\&Delta;<figure-callout\; id="1"\; label="t\; T"\; filenames="HDA0000440002890000011.png"\; state="\{\{state\}\}">t</figure-callout>}}{T_{}}}+K\&CenterDot;D_{\mathrm{coal}}(k-1)\&CenterDot;(1-e^{-\frac{\mathrm{\&Delta;t}}{T_1}})---\left(25\right)$

$Q_{\mathrm{sum}}\left(k\right)=Q_{\mathrm{sum}}(k-1)\&CenterDot;e^{-\frac{\mathrm{\&Delta;t}}{T_2}}+Q_{\mathrm{furnace}}(k-1)\&CenterDot;(1-e^{-\frac{\mathrm{\&Delta;t}}{T_2}})---\left(26\right)$

Preferably, in step 6, amplification coefficient K, enters stove coal net calorific value described in and obtains by parameter identification method, and objective function is:

In formula, N represents to carry out the selected time window width of parameter identification,

the predicted value that represents high-temperature flue gas transferring energy summation, the restriction range of K is determined according to the fire coal species of concrete unit, T ₁, T ₂restriction range according to the combustion process of concrete unit and time that flue gas is flowed through in flue, determine.

Compared with prior art, the present invention has following beneficial effect:

The present invention has realized entering the on-line identification of stove coal net calorific value, processing speed fast (be a second level computing time), and net calorific value identification precision is high, and implementation cost is low; Based on the present invention, can implement coal-supplying amount compensation and Optimized Coal Blending, to steady production, the thermal efficiency of thermoelectricity flow process, excellent and energy-saving and emission-reduction have Great significance.

Accompanying drawing explanation

By reading the detailed description of non-limiting example being done with reference to the following drawings, it is more obvious that other features, objects and advantages of the present invention will become:

Fig. 1 is the main vapour pitch of one embodiment of the invention structural drawing;

Fig. 2 is that one embodiment of the invention high-temperature flue gas energy transmits schematic diagram;

Fig. 3 is one embodiment of the invention coal supply energy release process schematic diagram;

Fig. 4 is that one embodiment of the invention enters stove coal net calorific value identification result figure.

Embodiment

Below in conjunction with specific embodiment, the present invention is described in detail.Following examples will contribute to those skilled in the art further to understand the present invention, but not limit in any form the present invention.It should be pointed out that to those skilled in the art, without departing from the inventive concept of the premise, can also make some distortion and improvement.These all belong to protection scope of the present invention.

As shown in Figure 1, what the present embodiment related to certain subcritical 300MW firepower power station enters the real-time identification of stove coal net calorific value, boiler model HG-1025/17.3-WM18 type, boiler is Natural Circulation, resuperheat, " W " flame combustion mode, two arch list burner hearth, balanced ventilation, afterbody twin flue, gas baffle temperature adjustment, dry ash extraction, outdoor layout, all steel frame suspension type drum boiler.Heat transmission equipment in this natural circulation boiler flue mainly comprises superheater, reheater, economizer three parts.In Fig. 1: 1-valve rod, 2-valve pocket, 3-valve seat, 4-sleeve, 5-valve disc, position 0 refers to the steam inlet of valve pocket, position 1 refers to the steam (vapor) outlet of valve pocket.

The present embodiment provides a kind of coal fired power plant to enter stove coal net calorific value real-time identification method, and the method specifically comprises the following steps:

Step 1, according to boiler operatiopn design discipline, obtain the following structural parameters of boiler: heat exchanger tube is 568m along the total length L of Working fluid flow direction, and wherein superheater overall length is 396.7m, and reheater total length is 123.5m; Total length L is divided into 5202 sections of isometric short tubes, and every section of short tube length setting is 0.1m; Heat interchanger is along the heat exchanger tube sectional area distribution A (i) (i.e. the sectional area of i section short tube) of Working fluid flow direction; Heat interchanger metallic walls quality 1244871kg;

From the real-time data base of DCS control system, read the operation condition real time data under given time k: drum pressure 17.6MPa, main steam mass rate 233.6kg/s, reheat heat steam flow 192.1kg/s, economizer exit feedwater flow 236.6kg/s, each section of short tube Temperature of Working of heat interchanger at different levels (first 387.9 ℃ of superheater one-level attemperator, after superheater one-level attemperator 379.1 ℃, first 472.9 ℃ of superheater secondary attemperator, after superheater secondary attemperator 472.0 ℃, superheater outlet is 538.7 ℃, 304.5 ℃ of reheater entrances, 535.3 ℃ of reheater outlets, 263 ℃ of economizer entrances, 286.2 ℃ of economizer exit) and pressure (superheater entrance is 17.46MPa, superheater outlet is 16.61MPa, reheater entrance 2.871MPa, reheater outlet 2.682MPa, economizer entrance 17.963MPa, economizer exit 17.6MPa), 380.5 ℃ of heat interchanger metallic walls temperature, 120.2 ℃ of the exhaust gas temperatures at flue outlet induced draft fan place and the volumetric flow rate 320m of smoke evacuation ³/ s, boiler load 230MW and environment atmospheric pressure 0.087MPa.

Step 2, according to working medium physical parameter storehouse and drum pressure, calculate this given time water drum outlet saturated vapour specific enthalpy h _bhand density p _bh, temperature, the pressure of establishing working medium between the adjacent crucial measuring point of heat interchanger at different levels are linear distribution simultaneously, the working medium specific enthalpy h of the infinitesimal section of dividing in calculation procedure one _gzand density p (i) _gz(i); According to flue gas physical parameter storehouse and exit gas temperature, pressure, atmospheric pressure, calculate the specific heat c of exit gas under this given time _pyand density p _py.

Described working medium physical parameter storehouse, refer to can parallel calling according to having of water and steam thermodynamic properties industry formula (IAPWS-IF97) exploitation, the feature such as region automatic discrimination, batch processing computing for the working medium physical parameter storehouse in line computation, can list of references: Wang Xuhui, in red, Hui Zhaoyu, Yuan Jingqi, for the working medium physical parameter database of thermoelectricity gamut emulation, control engineering, 2011; 18:131-133.

Described flue gas physical parameter storehouse, refers to by flue gas pressures and temperature real time data at the specific heat of line computation flue gas and the Data Base of Chemical Compound of density.Can list of references: Cai Wei, in red, Hui Zhaoyu, Yuan Jingqi, Zhang Ruifeng, Chen Yu, the On-line Estimation of apparatus of thermo-electric power boiler heat loss due to exhaust gas, control engineering, 2011; 18:149-151.

Step 3, the relational model based on main vapour pitch aperture and main steam mass rate (main vapour pitch structure as shown in Figure 1), according to real-time main vapour pitch aperture correction main steam mass rate, particularly: based on main vapour pitch aperture and main steam mass rate characteristic, the DCS measured data of pitch group and the dynamic perfromance of over-temperature channel heat interchanger at different levels and drum, revise in time main steam maskantflowmeter observation value, thereby obtain the main steam mass rate matching with actual furnace coal weight and feedwater flow.

Described main vapour pitch aperture and main steam mass rate characteristic, refer to the sectional type nonlinear function that main vapour pitch aperture is corresponding with main steam mass rate.Can list of references: Liu Xin, in red, Yuan Jingqi, foundation and the application of 300MW steamer owner vapour pitch group model, control engineering, 2012; 19:1183-1186.

This is because main vapour pitch while changing, is not changed and caused by feedwater and Coal-fired capacity in the dynamic increment short time of main steam mass rate, but has utilized the vapour appearance characteristic of over-temperature channel heat interchanger and drum.The instantaneous change of main steam meeting after main vapour pitch aperture changes, but coal-supplying amount and feedwater flow need to pass through main steam pressure control and pulverized coal preparation system controlling unit just change, and therefore need to revise main steam maskantflowmeter observation value.

Described correction main steam mass rate D _msmethod be:

$D_{\mathrm{ms}}=\underset{n=1}{\overset{5}{\mathrm{\&Sigma;}}}\frac{\mathrm{\&alpha;f}\left(L_n\right)p_0}{\sqrt{T_0}}---\left(1\right)$

In formula: α value 0.137, f (﹒) represent aperture-mass rate corresponding relation of main vapour pitch, L _nrepresent revised main vapour pitch aperture, p ₀represent main steam pressure, T ₀represent main steam temperature;

L wherein _ncomputing method be:

L _n(k)=ΔL _n(k)+L _n0 (2)

$\frac{\mathrm{\&Delta;}{L}_n\left(s\right)}{{\mathrm{\&Delta;L}}_{\mathrm{ms}}\left(s\right)}=\frac{1}{1+\mathrm{Ts}}---\left(3\right)$

The difference form of formula (3) is:

${\mathrm{\&Delta;L}}_n\left(k\right)={\mathrm{\&Delta;L}}_n(k-1)\&CenterDot;e^{-\frac{\mathrm{\&Delta;t}}{T}}+{\mathrm{\&Delta;L}}_{\mathrm{ms}}(k-1)\&CenterDot;(1-e^{-\frac{\mathrm{\&Delta;t}}{T}})---\left(5\right)$

In formula: Δ L _msfor the main vapour pitch aperture increment of Real-time Feedback, Δ L _nrepresent revised main vapour pitch aperture increment, L _n0represent the main vapour pitch aperture before working conditions change, s represents Laplace operator, and T represents the equivalent time constant of main steam pressure control loop and pulverized coal preparation system, and Δ t is the sampling period, is 5 seconds in the present embodiment, and k is current given time, and k-1 is previous moment.

Step 4, according to boiler side whole process mechanism model, calculate respectively the output of boiler side each several part energy under this given time and gross energy and export (high-temperature flue gas energy transfer process is as shown in Figure 2), wherein:

Enter the gross energy Q that the perfect combustion of stove coal produces and transmits _sumwhereabouts is divided into two parts: first is that boiler system is effectively utilized heat Q ₁, can further be decomposed into water-cooling wall caloric receptivity Q _slbwith heat interchanger at different levels, comprise superheaters at different levels, reheater, economizer heat exchange amount Q _heatex; Second portion is thermal loss, can further be decomposed into heat loss due to exhaust gas energy Q ₂, heat loss due to unburned gas energy Q ₃, heat loss due to combustibles in refuse energy Q ₄, boiler radiation loss energy Q ₅, heat loss due to sensible heat in slag's energy Q ₆; Boiler radiation loss energy Q ₅in gross energy, proportion is q ₅, q ₅by experimental formula, be easy to obtain, therefore enter the gross energy Q that the perfect combustion of stove coal produces and transmits _sumcan be expressed as:

Q _sum=(Q _heatex+Q _slb+Q ₂+Q ₃+Q ₄+Q ₆)/(1-q ₅) (5)

In the present embodiment, described boiler side whole process mechanism model comprise water-cooling wall caloric receptivity computation model, at different levels overheated/reheater heat exchange amount computation model, economizer heat exchange amount computation model, thermal loss computation model, concrete:

Described water-cooling wall caloric receptivity computation model, by setting up energy and the dynamic mechanism model of quality of the whole boiler circuit that drum, downtake, water-cooling wall form, calculate, specifically can adopt the technology in method for real-time measurement (patent ZL2010112300066930) the > > of patent of invention < < boiler water wall caloric receptivity to realize;

Described at different levels overheated/heat exchanger heat exchange amount computation model again, refer to that the infinitesimal section based on described in step 1 is divided, utilize quality, energy dynamics balance equation, calculate under this given time at different levels overheated/heat exchanger working medium heat exchange amount again; Particularly:

The dynamic balance equation of quality:

$\mathrm{dD}=D\left(k\right)-D(k-1)=\underset{i=1}{\overset{L/0.1}{\mathrm{\&Sigma;}}}{\mathrm{\&rho;}}_i\left(k\right)A_i\&CenterDot;0.1-\underset{i=1}{\overset{L/0.1}{\mathrm{\&Sigma;}}}{\mathrm{\&rho;}}_i(k-1)A_i\&CenterDot;0.1---\left(6\right)$

$D_{\mathrm{in}}=\frac{\mathrm{dD}}{\mathrm{dt}}+D_{\mathrm{out}}---\left(7\right)$

In formula: D is overheated/working medium total mass flow rate in heat exchanger system again, ρ _ifor overheated/density of working medium in passage of heat i discrete infinitesimal again, A _ifor the overheated/equivalent circulation area of passage of heat i discrete infinitesimal again, for superheater, D _infor drum outlet (being over-temperature channel entrance) saturated vapour mass rate, D _outfor over-temperature channel outlet (being high pressure cylinder entrance) superheated vapor (being main steam) mass rate, for reheater, D _infor the cold reheated steam mass rate of passage of heat entrance again (being high pressure cylinder outlet), D _outfor the outlet of the passage of heat again (being intermediate pressure cylinder entrance) reheat heat steam mass flow; Dt is time differential.

Energy dynamics balance equation:

$\begin{array}{c}\mathrm{dE}=E\left(k\right)-E(k-1)=\underset{i=1}{\overset{L/0.1}{\mathrm{\&Sigma;}}}{\mathrm{\&rho;}}_i\left(k\right)h_i\left(k\right)A_i\&CenterDot;0.1-\underset{i=1}{\overset{L/0.1}{\mathrm{\&Sigma;}}}{\mathrm{\&rho;}}_i(k-1)h_i(k-1)A\left(i\right)\&CenterDot;0.1\\ +c_{\mathrm{metal}}{M}_{\mathrm{metal}}\&CenterDot;{\mathrm{dT}}_{\mathrm{metal}}\end{array}---\left(8\right)$

$Q=\frac{\mathrm{dE}}{\mathrm{dt}}+D_{\mathrm{out}}{h}_{\mathrm{out}}-D_{\mathrm{in}}{h}_{\mathrm{in}}---\left(9\right)$

In formula: E is overheated/passage of heat working medium gross energy again, h _ifor overheated/specific enthalpy of working medium in passage of heat i discrete infinitesimal again, c _metal, M _metalwith Δ T _metalfor overheated/specific heat, gross mass and metallic walls temperature increment of passage of heat metallic walls again, Q is overheated/passage of heat working medium obtains from flue gas again energy, h _inand h _outbe respectively overheated/again passage of heat inlet steam specific enthalpy and outlet specific steam enthalpy;

Described economizer working medium caloric receptivity computation model, because water in economizer is liquid, compressibility is very little, and energy can be accumulated hardly, therefore adopt energy homeostasis to account model, calculates:

Q _sm=D _fw·(h' _out-h _i' _n) (10)

In formula: D _fwfeed-water quality flow, h ' _inand h ' _outbe respectively economizer entrance feedwater specific enthalpy and economizer exit feedwater specific enthalpy;

Described thermal loss computation model, wherein each several part thermal loss adopts experimental formula to calculate, and according to following prior art, is calculated:

Q ₂=K ₁(Q _py-Q _lf) (11)

Q ₃=0 (12)

Q ₄=Q _cc·(G _fh C _fh+G _lz·C _lz) (13)

${\mathrm{<figure-callout\; id="5"\; label="q"\; filenames="HDA0000440002890000011.png"\; state="\{\{state\}\}">q</figure-callout>}}_5=5.82\&CenterDot;{\left(D_e\right)}^{-0.38}\&CenterDot;\frac{D_e}{D}---\left(14\right)$

Q ₆=c _fh·G _fh·t _fh+c _lz·G _lz·t _lz (15)

In formula: K ₁into the imperfect combustion modified value of stove coal solid, Q _pysmoke evacuation energy, Ql _fcold air energy, Q _ccthe net calorific value that represents pure carbon, Q _cc=32.7MJ/kg, G _fh, G _lzrespectively the mass rate of flying dust and slag, C _lzthe carbon content of slag, C _fhunburned carbon in flue dust, D _ebe the rated capacity of boiler, D is actual evaporation, equates c with main steam mass rate _fh, c _lzrespectively the specific heat capacity of flying dust and slag, t _fh, t _lzbe respectively fly, the temperature of ash and slag;

Above-mentioned related parameter obtains by following formula:

K ₁=1-q ₄ (16)

q ₄=A _ad·A _fh·C _fh/F _cad (17)

Q _py=c _py·ρ _py·V _py·(t _py+273.15) (18)

Q _lf=c _lf·ρ _lf·V _lf·(t _lf+273.15) (19)

c _fh=0.71+0.000502·t _fh (20)

c _lz=0.71+0.000502·t _lz(21)

In formula: q ₄into stove coal solid-unburning hot loss number percent, A _adinto stove ash content of coal content, A _fhthe fly ash content in ash content, F _cadbe that c is the specific heats of gases into stove coal fixed carbon content, ρ is gas density, and V is gas flow, and t is gas temperature, and subscript py and lf represent respectively smoke evacuation and cold air.

Step 5, set up feeder coal supply mass rate and enter the transfer function model between stove coal mass rate, can adopt first order inertial loop model to characterize:

$\frac{D_{\mathrm{coal}}\left(s\right)}{D_{\mathrm{belt}}\left(s\right)}=\frac{1}{1+\mathrm{Ts}}---\left(22\right)$

Turn to difference form:

$D_{\mathrm{coal}}\left(k\right)=D_{\mathrm{coal}}(k-1)\&CenterDot;e^{-\frac{\mathrm{\&Delta;t}}{T}}+D_{\mathrm{belt}}(k-1)\&CenterDot;(1-e^{-\frac{\mathrm{\&Delta;t}}{T}})---\left(23\right)$

In formula: D _coalrepresent into stove coal mass rate, D _beltrepresent feeder coal supply mass rate, T represents coal pulverizer closed-loop control link and grinds the total equivalent time constant of link.

Step 6, fire coal is entered to stove to take main steam, be between main energy output that phase relation is decomposed into coal and to working medium, transmit two processes at stove chamber inner combustion and heating power, with first order inertial loop, characterize this two processes respectively, thereby set up the phase relation transfer function model between stove coal mass rate and gross energy output:

$\frac{Q_{\mathrm{sum}}\left(s\right)}{D_{\mathrm{coal}}\left(s\right)}=\frac{Q_{\mathrm{furnace}}\left(s\right)}{D_{\mathrm{coal}}\left(s\right)}\&CenterDot;\frac{Q_{\mathrm{sum}}\left(s\right)}{Q_{\mathrm{furnace}}}=\frac{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HDA0000440002890000011.png"\; state="\{\{state\}\}">K</figure-callout>}}{1+T_{1}s}\&CenterDot;\frac{1}{1+T_2\text{s}}---\left(24\right)$

In formula: Q _furnacerepresent to release energy at hearth combustion into stove coal, Q _sumrepresent the boiler side whole process gross energy output under given time k, K is amplification coefficient, and its physical significance is for entering stove coal net calorific value, T ₁for entering the time constant of stove coal combustion process, T ₂for the equivalent time constant of heating power to refrigerant heat transfer process.

Resulting transfer function model is carried out to discretize and obtains difference equation model:

$Q_{\mathrm{furnace}}\left(k\right)=Q_{\mathrm{furnace}}(k-1)\&CenterDot;e^{-\frac{\mathrm{\&Delta;<figure-callout\; id="1"\; label="t\; T"\; filenames="HDA0000440002890000011.png"\; state="\{\{state\}\}">t</figure-callout>}}{T_{}}}+K\&CenterDot;D_{\mathrm{coal}}(k-1)\&CenterDot;(1-e^{-\frac{\mathrm{\&Delta;t}}{T_1}})---\left(25\right)$

$Q_{\mathrm{sum}}\left(k\right)=Q_{\mathrm{sum}}(k-1)\&CenterDot;e^{-\frac{\mathrm{\&Delta;t}}{T_2}}+Q_{\mathrm{furnace}}(k-1)\&CenterDot;(1-e^{-\frac{\mathrm{\&Delta;t}}{T_2}})---\left(26\right)$

Further identification amplification coefficient K, its physical significance is exactly corresponding with gross energy output under this given time stove coal net calorific value that enters, and by simplex discrimination method, obtains, and objective function is:

In formula: N represents to carry out the selected time window width of parameter identification,

the predicted value that represents high-temperature flue gas transferring energy summation, in the present embodiment, to be taken as 120, K restriction range be [13,25] to N, T ₁restriction range is [0,600], T ₂restriction range is [0,600].

In DCS control system, configuration realizes the method at the scene, be illustrated in figure 4 continuous operation and investigate the result drawing after (totally 816 hours) for 34 days, wherein: solid black lines is identification net calorific value, black round dot is every 6 hours off-line chemical examination net calorific values once.

The present invention has realized entering the on-line identification of stove coal net calorific value, processing speed fast (be a second level computing time), and net calorific value identification precision is high, and implementation cost is low; Based on the present invention, can implement coal-supplying amount compensation and Optimized Coal Blending, to steady production, the thermal efficiency of thermoelectricity flow process, excellent and energy-saving and emission-reduction have Great significance.

Above specific embodiments of the invention are described.It will be appreciated that, the present invention is not limited to above-mentioned specific implementations, and those skilled in the art can make various distortion or modification within the scope of the claims, and this does not affect flesh and blood of the present invention.

Claims (7)

1. coal fired power plant enters a real-time identification method for stove coal net calorific value, it is characterized in that, the method comprises the following steps:

Step 1, according to boiler operatiopn design discipline, obtain the following structural parameters of boiler: heat exchanger tube at different levels are along total length, sectional area distribution, the heat interchanger metallic walls quality of Working fluid flow direction; From the real-time data base of DCS control system, read the operation condition real time data under given time, specifically comprise: exhaust gas temperature, volumetric flow rate, boiler load and the environment atmospheric pressure at the Temperature of Working at drum pressure, main steam mass rate, reheat heat steam mass flow, economizer exit feed-water quality flow, heat interchanger measuring points at different levels place and pressure, heat interchanger metallic walls temperature, flue outlet induced draft fan place;

Step 2, according to working medium physical parameter storehouse and drum pressure, calculate this given time water drum outlet saturated vapour specific enthalpy and density, temperature, the pressure of establishing working medium between the adjacent crucial measuring point of heat interchanger at different levels are linear distribution simultaneously, and by fixing discretize length, heat interchanger at different levels are divided into series of discrete infinitesimal, calculate working medium specific enthalpy and the density of each infinitesimal; According to flue gas physical parameter storehouse and exit gas temperature, pressure, atmospheric pressure, calculate specific heat and the density of exit gas under this given time;

Step 3, the relational model based on main vapour pitch aperture and main steam mass rate, according to real-time main vapour pitch aperture correction main steam mass rate, particularly: based on main vapour pitch aperture and main steam mass rate characteristic, the DCS measured data of pitch group and the dynamic perfromance of over-temperature channel heat interchanger at different levels and drum, revise in time main steam maskantflowmeter observation value, thereby obtain the main steam mass rate matching with actual furnace coal weight and feedwater flow;

Step 4, according to boiler side whole process mechanism model, calculate respectively the output of corresponding boiler side each several part energy and gross energy and export, wherein enter the gross energy Q that the perfect combustion of stove coal produces and transmits _sumwhereabouts is divided into two parts: first is that boiler system is effectively utilized heat Q ₁, can further be decomposed into water-cooling wall caloric receptivity Q _slbwith heat interchanger at different levels, comprise superheaters at different levels, reheater, economizer heat exchange amount Q _heatex; Second portion is thermal loss, can further be decomposed into heat loss due to exhaust gas energy Q ₂, heat loss due to unburned gas energy Q ₃, heat loss due to combustibles in refuse energy Q ₄, boiler radiation loss energy Q ₅, heat loss due to sensible heat in slag's energy Q ₆; Boiler radiation loss energy Q ₅in gross energy, proportion is q ₅, q ₅by experimental formula, obtain, enter the gross energy Q that the perfect combustion of stove coal produces and transmits _sumbe expressed as:

Q _sum＝(Q _heatex+Q _slb+Q ₂+Q ₃+Q ₄+Q ₆)/(1-q ₅)

Step 5, set up feeder coal supply mass rate and enter the transfer function model between stove coal mass rate, obtain into stove coal mass rate;

Step 6, fire coal is entered to stove to take main steam, be between main energy output that phase relation is decomposed into coal dust and to working medium, transmit two processes at stove chamber inner combustion and heating power, and then set up the phase relation transfer function model between the output of stove coal mass rate and gross energy, by parameter identification, obtains with gross energy under this given time and export corresponding enter stove coal mass rate and net calorific value.

2. a kind of coal fired power plant according to claim 1 enters the real-time identification method of stove coal net calorific value, it is characterized in that, and in step 3, described correction main steam mass rate D _msmethod be:

$D_{\mathrm{ms}}=\underset{n=1}{\overset{5}{\mathrm{\&Sigma;}}}\frac{\mathrm{\&alpha;f}\left(L_n\right)p_0}{\sqrt{T_0}}$

In formula, α is model parameter, f (﹒) represent aperture-mass rate characteristic of main vapour pitch, L _nrepresent revised main vapour pitch aperture, p ₀represent main steam pressure, T ₀represent main steam temperature;

Wherein:

L _n(k)＝ΔL _n(k)+L _n0

$\frac{\mathrm{\&Delta;}{L}_n\left(s\right)}{{\mathrm{\&Delta;L}}_{\mathrm{ms}}\left(s\right)}=\frac{1}{1+\mathrm{Ts}}$

Above formula is turned to difference form, that is:

${\mathrm{\&Delta;L}}_n\left(k\right)={\mathrm{\&Delta;L}}_n(k-1)\&CenterDot;e^{-\frac{\mathrm{\&Delta;t}}{T}}+{\mathrm{\&Delta;L}}_{\mathrm{ms}}(k-1)\&CenterDot;(1-e^{-\frac{\mathrm{\&Delta;t}}{T}})$

In formula, Δ L _msfor the main vapour pitch aperture increment of Real-time Feedback, Δ L _nrepresent revised main vapour pitch aperture increment, L _n0represent the main vapour pitch aperture before working conditions change, s represents Laplace operator, and T represents the equivalent time constant of main steam pressure control loop and pulverized coal preparation system, and Δ t is the sampling period, and k is current given time, and k-1 is previous moment.

3. a kind of coal fired power plant according to claim 1 enters the real-time identification method of stove coal net calorific value, it is characterized in that, in step 4, described boiler side whole process mechanism model comprises: water-cooling wall caloric receptivity computation model, at different levels overheated/reheater heat exchange amount computation model, economizer heat exchange amount computation model, thermal loss computation model; Particularly:

Described water-cooling wall caloric receptivity computation model, calculates by setting up energy and the dynamic mechanism model of quality of the whole boiler circuit of drum, downtake, water-cooling wall composition;

Described at different levels overheated/reheater heat exchange amount computation model, be establish at different levels overheated/between the adjacent measuring point of heat exchanger, temperature, the pressure of working medium are linear distribution again, and divide infinitesimal with fixing discretize length pipeline section, according to quality, energy dynamics balance equation, try to achieve at different levels overheated/heat exchanger heat exchange amount again; Wherein:

The dynamic balance equation of quality:

$\mathrm{dD}=D\left(k\right)-D(k-1)=\underset{i=1}{\overset{L/0.1}{\mathrm{\&Sigma;}}}{\mathrm{\&rho;}}_i\left(k\right)A_i\&CenterDot;0.1-\underset{i=1}{\overset{L/0.1}{\mathrm{\&Sigma;}}}{\mathrm{\&rho;}}_i(k-1)A_i\&CenterDot;0.1$

$D_{\mathrm{in}}=\frac{\mathrm{dD}}{\mathrm{dt}}+D_{\mathrm{out}}$

In formula, D is overheated/working medium total mass flow rate in heat exchanger system again, ρ _ifor overheated/density of working medium in passage of heat i discrete infinitesimal again, A _ifor the overheated/equivalent circulation area of passage of heat i discrete infinitesimal again, D _in, D _outbe respectively overheated/again passage of heat entrance, outlet steam mass flow, dt is time differential;

Energy dynamics balance equation:

$\begin{array}{c}\mathrm{dE}=E\left(k\right)-E(k-1)=\underset{i=1}{\overset{L/0.1}{\mathrm{\&Sigma;}}}{\mathrm{\&rho;}}_i\left(k\right)h_i\left(k\right)A_i\&CenterDot;0.1-\underset{i=1}{\overset{L/0.1}{\mathrm{\&Sigma;}}}{\mathrm{\&rho;}}_i(k-1)h_i(k-1)A\left(i\right)\&CenterDot;0.1\\ +c_{\mathrm{metal}}{M}_{\mathrm{metal}}\&CenterDot;{\mathrm{dT}}_{\mathrm{metal}}\end{array}$

$Q=\frac{\mathrm{dE}}{\mathrm{dt}}+D_{\mathrm{out}}{h}_{\mathrm{out}}-D_{\mathrm{in}}{h}_{\mathrm{in}}$

In formula, E is overheated/passage of heat working medium gross energy again, h _ifor overheated/specific enthalpy of working medium in passage of heat i discrete infinitesimal again, c _metal, M _metalwith Δ T _metalfor overheated/specific heat, gross mass and metallic walls temperature increment of passage of heat metallic walls again, Q is overheated/passage of heat working medium obtains from flue gas again energy, h _in, h _outbe respectively overheated/again passage of heat entrance, outlet specific steam enthalpy;

Described economizer heat exchange amount computation model adopts energy homeostasis to account model and calculates:

Q _sm＝D _fw·(h' _out-h _i' _n)

In formula, D _fwfor feed-water quality flow, h ' _inand h ' _outbe respectively economizer entrance feedwater specific enthalpy and economizer exit feedwater specific enthalpy;

Described thermal loss computation model, wherein each several part thermal loss adopts experimental formula to calculate.

4. a kind of coal fired power plant according to claim 1 enters the real-time identification method of stove coal net calorific value, it is characterized in that, in step 5, described feeder coal supply mass rate and the transfer function model entering between stove coal mass rate adopt first order inertial loop model to characterize:

$\frac{D_{\mathrm{coal}}\left(s\right)}{D_{\mathrm{belt}}\left(s\right)}=\frac{1}{1+\mathrm{Ts}}$

Turning to difference form can obtain:

$D_{\mathrm{coal}}\left(k\right)=D_{\mathrm{coal}}(k-1)\&CenterDot;e^{-\frac{\mathrm{\&Delta;t}}{T}}+D_{\mathrm{belt}}(k-1)\&CenterDot;(1-e^{-\frac{\mathrm{\&Delta;t}}{T}})$

In formula, D _coalrepresent into stove coal mass rate, D _beltrepresent feeder coal supply mass rate, T represents coal pulverizer closed-loop control link and grinds the total equivalent time constant of link.

5. according to a kind of power station described in claim 1-4 any one, enter stove coal net calorific value real-time identification method, it is characterized in that, in step 6, the described phase relation transfer function model entering between stove coal mass rate and gross energy output, refer to that adopting respectively first order inertial loop to characterize coal dust transmits two processes to working medium, the order transfer function model finally obtaining at stove chamber inner combustion and heating power:

$\frac{Q_{\mathrm{sum}}\left(s\right)}{D_{\mathrm{coal}}\left(s\right)}=\frac{Q_{\mathrm{furnace}}\left(s\right)}{D_{\mathrm{coal}}\left(s\right)}\&CenterDot;\frac{Q_{\mathrm{sum}}\left(s\right)}{Q_{\mathrm{furnace}}}=\frac{K}{1+T_{1}s}\&CenterDot;\frac{1}{1+T_2\text{s}}$

In formula, Q _furnacerepresent to release energy at hearth combustion into stove coal, Q _sumthe summation that represents the output of boiler side whole process each several part energy, K represents model amplification coefficient, its physical significance is for entering stove coal net calorific value, T ₁for the time constant of process of coal combustion, T ₂for the equivalent time constant of heating power to refrigerant heat transfer process.

6. a kind of coal fired power plant according to claim 5 enters the real-time identification method of stove coal net calorific value, it is characterized in that, in step 6, the described phase relation transfer function model entering between stove coal mass rate and gross energy output carried out to the difference equation model that discretize obtains be:

$Q_{\mathrm{furnace}}\left(k\right)=Q_{\mathrm{furnace}}(k-1)\&CenterDot;e^{-\frac{\mathrm{\&Delta;t}}{T_1}}+K\&CenterDot;D_{\mathrm{coal}}(k-1)\&CenterDot;(1-e^{-\frac{\mathrm{\&Delta;t}}{T_1}})$

$Q_{\mathrm{sum}}\left(k\right)=Q_{\mathrm{sum}}(k-1)\&CenterDot;e^{-\frac{\mathrm{\&Delta;t}}{T_2}}+Q_{\mathrm{furnace}}(k-1)\&CenterDot;(1-e^{-\frac{\mathrm{\&Delta;t}}{T_2}}).$

7. a kind of coal fired power plant according to claim 6 enters the real-time identification method of stove coal net calorific value, it is characterized in that, in step 6, amplification coefficient K, enters stove coal net calorific value described in and obtain by parameter identification method, and objective function is:

In formula, N represents to carry out the selected time window width of parameter identification, the predicted value that represents high-temperature flue gas transferring energy summation.

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