CN102645523B - Moisture as received coal on-line identification method based on heat balance of powder process system - Google Patents

Abstract

The invention discloses a moisture as received coal on-line identification method based on the heat balance of a powder process system and belongs to the technical field of coal quality on-line identification of power stations. According to the moisture as received coal on-line identification method, on the basis of the heat balance mechanism analysis, by means of comprehensive optimization strategies of multi-mill optimization, closely integrated with the mainstream coal blending co-firing way of coal-fired power plants, the on-line identification method provides a complete on-line identification system which is capable of simultaneously reflecting the real-time values and characteristics of types of the moisture as received coal, and the moisture as received coal on-line identification method has the advantages of being capable of improving the accuracy and the stability of identification results, improving the accuracy and the reliability of the final identification results, and effectively eliminating abnormal situations of the saltation of identification types.

Description

Based on pulverized coal preparation system thermally equilibrated as-fired coal moisture as received coal on-line identification method

Technical field

The invention belongs to power station ature of coal on-line identification technical field, particularly based on pulverized coal preparation system thermally equilibrated as-fired coal moisture as received coal on-line identification method.

Background technology

For the present situation of current " energy scarcity, market coal, plan electricity ", it is various and ature of coal is changeable, the property indices off-design coal far away of as-fired coal that coal in power plant shows as source mostly; On the other hand, increasing power plant is by carrying out coal mixing combustion work enhancing efficiency by relying on tapping internal latent power, " stokehold blending; full storehouse coal blending " and " point storehouse coal blending; mix burning in stove " are that two kinds of common at present main flows mix burning mode, the former be applicable to the close situation of coal characteristic be conducive to catching fire of coal dust and burn stable, the latter be applied to more coal characteristic especially the grindability situation that differs greatly ensure that rational fineness of pulverized coal and uniformity coefficient, the widespread use of coal mixing combustion makes the fluctuation situation more complicated difficult control of actual as-fired coal matter.

To the monitoring of as-fired coal matter, current power plant rests on the level of hand sampling, sample preparation, chemical examination substantially, there is serious delayed and sampling error, operations staff's needs cannot be met at all and hold as-fired coal matter situation in real time thus an urgent demand of Optimum Operation guidance operation, therefore, be difficulties urgently to be resolved hurrily to the on-line identification of ature of coal, the increasingly sophisticated of application scenarios is also had higher requirement to this problem and challenges always.

As-fired coal moisture as received coal is coal-fired main performance index, to the security of boiler operatiopn and economic influence very large.As higher in the moisture in fire coal, then the net heat of releasing during burning reduces, and exhaust gas temperature raises, and boiler efficiency reduces, and induced draft fan power consumption increases, and affects pulverized coal preparation system drying capacity, causes adverse consequencess such as cohering blocking.Method at present for Fast Measurement Coal ' moisture has infrared method, conductance method, capacitance method, microwave method and neutron activation method etc.The mainly microwave method wherein extensively adopted, market share is more than 85%.Next is capacitance method, market share about 12%.To the on-line identification of as-fired coal moisture as received coal, realize mainly through the instrument and equipment installed based on above-mentioned measuring principle, the deficiency of this hard monitoring mode is:

1) hardware device is expensive, needs to take power plant's substantial contribution cost;

2) work under bad environment of power plant, to the accuracy of on-line monitoring instrument and durability requirements higher;

3) the coal sample diffuse reflection that relies on of measurement result or transmission signal very weak, the accuracy impact of the situation such as fineness, bulk density thickness on on-line monitoring result of on-the-spot coal dust is very large.

4) to " point storehouse coal blending, mixes burning in stove " application scenarios, equipment sampled point need change with mixing burning coal quantity, causes system complex high cost;

Along with the maturation of domestic Real-Time Databases System Technique and soft-measuring technique in recent years, some scholars utilizes the pulverized coal preparation system on-line measurement auxiliary variable and off-line analysis information that store in real-time data base, identification modeling is carried out, to solve the on-line identification problem of as-fired coal moisture as received coal by the method for collection in worksite, flowsheeting, heat balance mechanism analysis or experimental test.Though these flexible measurement methods have a clear superiority in fund cost than hard monitoring mode, tend to theoretical research analysis, practical implementation is few more, lacks the comprehensive consideration to power plant's complex application context, does not form a set of complete on-line identification system.Weak point comprises:

1) indefinite to the applicable elements scope of heat balance mechanism, do not consider the impact of actual condition fluctuation on the calculated results;

2) general is that object carries out moisture as received coal model solution with one mill, does not consider the overall treatment application of multiple stage mill notional result;

3) do not carry out overall modeling analysis in conjunction with the concrete coal mixing combustion scheme of power plant, the on-line identification of the moisture as received coal to each coal blending kind and mixed coal cannot be realized;

4) do not carry out the judge analysis of as-fired coal moisture as received coal classification, the moisture instantaneous value only by calculating generally is difficult to directly apply in DCS closed-loop control, performance Index Calculation or economic analysis.

Summary of the invention

The present invention is directed to above-mentioned defect to disclose based on pulverized coal preparation system thermally equilibrated as-fired coal moisture as received coal on-line identification method.The present invention is based on the heat balance mechanism analysis of pulverized coal preparation system, adopt the preferred synthesizing evolutionary of many mills, the coal mixing combustion mode of coal-burning power plant's main flow of combining closely, provides the on-line identification system that simultaneously can reflect as-fired coal moisture as received coal instantaneous value and category feature of complete set.The present invention is applicable to Thermal generation unit.

Comprise the following steps based on pulverized coal preparation system thermally equilibrated as-fired coal moisture as received coal on-line identification method:

1) the coal mixing combustion scheme that power plant adopts for coal unit is divided into two kinds, in the first coal mixing combustion scheme, adopts: " stokehold blending, the coal blending of full storehouse "; In the second coal mixing combustion scheme, adopt: " point storehouse coal blending, mixes burning in stove ";

For the first coal mixing combustion scheme, the 1st coal pulverizer is mixed coal to the coal that M coal pulverizer grinds, and mixed coal is that coal is formed after blending; M gets 3 to 10;

For the second coal mixing combustion scheme, the Lower heat value of coal blending is V, and when V >=5000 kilocalorie, coal blending is high card coal; When 4500 kilocalories≤V<5000 kilocalorie, coal blending is middle card coal; When V<4500 kilocalorie, coal blending is low card coal; Obtain the kind of the coal blending that jth coal pulverizer grinds, determine the quantity of the often kind of coal blending needing identification, j gets 1 to M;

2) arrange and start at the scope of application of condition to heat balance mechanism and retrain, for jth coal pulverizer, j gets 1 to M, arranges following three and starts at condition:

First condition of starting at is: the pulverized coal output B of jth coal pulverizer _n>=5.56Kg/s;

Second condition of starting at is: the entrance coal-air ratio g of jth coal pulverizer ₁meet 1.5≤g ₁≤ 3.5;

3rd condition of starting at is: for jth coal pulverizer, entrance coal-air ratio g ₁meet Sg. _{5min ± 5%}>=95%, and Sg. _{5min ± 2%}>=90%, meanwhile, outlet wind powder mixture temperature t ₂meet St. _{5min ± 5%}>=95% and St. _{5min ± 2}%>=90%;

Wherein, ${\mathrm{Sg}.}_{5\min .\&PlusMinus;5\%}=\frac{\mathrm{Ng}\&PlusMinus;5\%}{\mathrm{Ng}}\&times;100\%,{\mathrm{Sg}.}_{5\min .\&PlusMinus;2\%}=\frac{\mathrm{Ng}\&PlusMinus;2\%}{\mathrm{Ng}}\&times;100\%,$

Ng is the entrance coal-air ratio g calculating jth coal pulverizer in first 5 minutes of moment ₁historical data number, Ng _{± 5%}and Ng _{± 2%}computation process as follows: first, calculating first 5 minutes of moment in, calculate the entrance coal-air ratio g of jth coal pulverizer ₁the mean value of all historical datas, then, calculate the entrance coal-air ratio g of the jth coal pulverizer dropped in this mean value ± 5% scope ₁the number Ng of historical data _{± 5%}; Calculating drops on the entrance coal-air ratio g of the jth coal pulverizer in this mean value ± 2% scope ₁the number Ng of historical data _{± 2%};

${\mathrm{Sg}.}_{5\min .\&PlusMinus;5\%}=\frac{\mathrm{Ng}\&PlusMinus;5\%}{\mathrm{Nt}}\&times;100\%,{\mathrm{Sg}.}_{5\min .\&PlusMinus;2\%}=\frac{\mathrm{Ng}\&PlusMinus;2\%}{\mathrm{Nt}}\&times;100\%,$

Nt is the outlet wind powder mixture temperature t calculating jth coal pulverizer in first 5 minutes of moment ₂historical data number, Nt _{± 5%}and Nt _{± 2%}computation process as follows: first, calculating first 5 minutes of moment in, calculate the outlet wind powder mixture temperature t of jth coal pulverizer ₂the mean value of all historical datas, then, calculate the outlet wind powder mixture temperature t of the jth coal pulverizer dropped in this mean value ± 5% scope ₂the number Nt of historical data _{± 5%}; Calculating drops on the outlet wind powder mixture temperature t of the jth coal pulverizer in this mean value ± 2% scope ₂the number Nt of historical data _{± 2%};

Only have when above three conditions of starting at all meet, just solve the moisture as received coal m that jth coal pulverizer grinds coal _j; Otherwise, return and wait for that next computation period Resurvey data carry out starting at condition judgment;

3) for the first coal mixing combustion scheme, step 4 is performed);

For the second coal mixing combustion scheme, for step 1) often kind of coal blending dividing, optimize coal pulverizer combination, coal pulverizer combination is made up of to the 3rd coal pulverizer the 1st coal pulverizer;

After optimizing coal pulverizer combination, according to the moisture as received coal m of following formulae discovery coal blending _ar:

$m_{\mathrm{ar}}=\underset{i=1}{\overset{s}{\mathrm{\&Sigma;}}}(m_{\mathrm{ari}}\&times;\frac{B_{\mathrm{mi}}}{{\mathrm{\&Sigma;}}_{i=1}^s{B}_{\mathrm{mi}}})$

In above formula, m _arifor preferred i-th coal pulverizer grinds the moisture as received coal of coal, B _mifor the pulverized coal output of preferred i-th coal pulverizer, s is the quantity of the coal pulverizer optimized;

To the moisture as received coal m of coal blending _arcarry out classification judge, be described as follows:

Work as 0%<m _arwhen≤8%, the moisture as received coal of coal blending belongs to M1 classification; Work as 8%<m _arwhen≤12%, the moisture as received coal of coal blending belongs to M2 classification; Work as 12%<m _arwhen≤20%, the moisture as received coal of coal blending belongs to M3 classification; Work as 20%<m _arwhen≤100%, the moisture as received coal of coal blending belongs to M4 classification;

Obtain the generic of the moisture as received coal of last computation period coal blending, the moisture as received coal m of the coal blending then before the reading calculating moment in A1 minute _arhistorical data, be the smoothing filtering of time window with A2 minute, obtain filtered data sequence; This data sequence is arranged by one group of data sequencing temporally; The span of A1 is 5 to 15; The span of A2 is 1-3;

According to the sequencing of time, following judgement is carried out to each data in this data sequence: when the data of in data sequence are between given zone, then judge in second at after this A3: in data sequence, whether have data to be between given zone all the time, if had, think coal blending the generic of moisture as received coal undergo mutation; Otherwise the generic maintaining the moisture as received coal of last computation period coal blending is constant; The span of A3 is 60 to 180;

Deterministic process between given zone is as follows: when the generic of the moisture as received coal of last computation period coal blending is M1 classification, is [8%+4%*A4,12%] between given zone; When the generic of the moisture as received coal of last computation period coal blending is M2 classification, be [0,8%-8%*A4] or [12%+8%*A4,20%] between given zone; When the generic of the moisture as received coal of last computation period coal blending is M3 classification, be [8%, 12%-4%*A4] or [20%+80%*A4,100%] between given zone; When the generic of the moisture as received coal of last computation period coal blending is M4 classification, between given zone be [12%, 20%-8%*A4]; The span of A4 is 20% to 30%;

4) for the first coal mixing combustion scheme, step 3) coal blending replace with mixed coal, then according to step 3), optimize mixed coal corresponding coal pulverizer combination, calculate the moisture as received coal of mixed coal, the generic of mixed coal passed judgment on;

For the second coal mixing combustion scheme, the coal pulverizer that often kind of coal blending optimizes is merged, thus define coal pulverizer combination corresponding to the mixed coal preferably, then step 3) coal blending replace with mixed coal, according to step 3) calculate the moisture as received coal of mixed coal, then the generic of mixed coal is passed judgment on.

Described jth coal pulverizer grinds the moisture as received coal m of coal _jcomputation process as follows:

21) the total amount of heat q of jth coal pulverizer is entered _inwith the total amount of heat q taking jth coal pulverizer out of _outidentical, i.e. q _in=q _out; With every kg coal for benchmark, carry out step 22) and step 23) calculating;

22)q _in＝q _ag1+q _mac+q _1e+q _s,

In above formula, q _ag1for the heat of jth coal pulverizer brought into by drying agent, q _macfor the heat that mechanical friction when jth coal pulverizer works adds, q _1efor jth coal pulverizer bleeds the physical thermal of cold air, q _sfor jth coal pulverizer sealing air physical thermal;

q _ag1＝g ₁×C _ag1×t ₁，

In above formula, g ₁for jth coal pulverizer inlet coal-air ratio, g ₁=m _f/ B _m; m _ffor jth coal pulverizer inlet First air flow, unit is kg/s; B _mfor the pulverized coal output of jth coal pulverizer, unit is kg/s; t ₁for jth coal pulverizer inlet First air temperature, unit is DEG C; C _ag1refer to the drying agent average quality specific heat capacity when temperature is t1, unit is kJ/ (kg DEG C)

q _mac＝K _mac×E _m

In above formula, E _mfor the energy consumption of jth coal pulverizer, E _m=(U × I)/B _m; U is the voltage of jth coal pulverizer; I is the electric current of jth coal pulverizer; K _macfor jth coal pulverizer power input is converted into the coefficient of heat;

q _1e＝K _1e×g ₁×C _1e×t _1e，

In above formula, K _1efor the air leakage coefficient of jth coal pulverizer, at pressurized direct pulverizing coal system, K _1e=0; t _1efor the air temperature of the jth coal pulverizer that bleeds, unit is DEG C; C _1erefer to when temperature is t _1etime soft air specific heat capacity, unit is kJ/ (kg DEG C);

When negative pressure pulverized coal preparation system, q _s=0, when other situations, q _s=(m _s/ B _m) × C _s× t _s, m _sfor the sealing air quantity of jth coal pulverizer, unit is kg/s; t _sfor the sealing air temperature of jth coal pulverizer, unit is DEG C; C _srefer to when temperature is t _stime soft air specific heat capacity, unit is kJ/ (kg DEG C);

23)q _out＝q _ev+q _ag2+q _f+q ₅；

In above formula, q _evfor the heat that the moisture evaporating coal consumes; q _ag2for the heat that drying agent is taken away; q _ffor adding the heat that hot coal consumes; q ₅for the radiation loss of coal unit pulverized coal preparation system;

q _ev＝△M×(2500+C _H2o×t ₂-4.187×t _rc)，

In above formula, the moisture that △ M loses for 1kg raw coal every in dry run;

△ M=(m _j-M _mf)/(100-M _mf); m _jfor jth coal pulverizer grinds the moisture as received coal of coal; M _mfor jth coal pulverizer outlet coal dust contained humidity;

M _mf=0.048 × m _j× R ₉₀/ t ₂ ^0.46; R ₉₀for fineness of pulverized coal; C _h2o is that water vapor average specific heat at constant pressure holds, and unit is kJ/ (kg DEG C); t _rcfor raw coal temperature, unit is DEG C); t ₂for jth coal pulverizer outlet wind powder mixture temperature;

q _ag2＝(1+K _1e)×g ₁+(m _s/B _m)×C _ag2×t _2,

In above formula, C _ag2refer to when temperature is t ₂time drying agent average quality specific heat capacity, unit is kJ/ (kg DEG C)

q _f＝(100-m _j)/100×[C _dc+(4.18×M _mf)/(100-M _mf)]×(t ₂-t _rc),

In above formula, C _dcfor the specific heat capacity of moisture-free coal, unit is kJ/ (kg DEG C);

For unit pulverized-coal system q ₅=0.02 × q _in,

For the ball type pulverizer system q ₅=0.05 × q _in,

24) simultaneous step 21), step 22) and step 23) formula, the moisture as received coal m that jth coal pulverizer grinds coal can be calculated _j.

Described select coal pulverizer combination comprise the following steps:

31) for often kind of coal blending, according to step 1) obtain coal pulverizer corresponding to this kind of coal blending, corresponding coal pulverizer refers to: the coal pulverizer ground this kind of coal blending, choose these coal pulverizers historical data of first 3 months, when the coal-supplying amount of each coal pulverizer is greater than 5.56kg/s, round as horizontal ordinate downwards with the coal-supplying amount of this coal pulverizer, the identical numerical value of n group can be formed after different coal-supplying amounts rounds downwards, for often organizing identical numerical value, ask for the entrance coal-air ratio mean value of corresponding coal pulverizer, with this mean value for ordinate, draw the coal-air ratio family curve of each coal pulverizer respectively, the computation process of the entrance coal-air ratio mean value of the coal pulverizer under this coal-supplying amount is: after rounding downwards the coal-supplying amount of this coal pulverizer, averages to the entrance coal-air ratio of the coal pulverizer under identical coal-supplying amount,

32) for step 31) middle corresponding coal pulverizer, carry out the characteristic contrast of these coal pulverizer coal-air ratios, to be observed by curve and mathematical modeling judges that the mode combined finds out 2 ~ 3 curves be parallel to each other, then coal pulverizer corresponding for these curves is combined as the coal pulverizer after preferred.

The detailed process of described curve observation and mathematical modeling is as follows:

First by step 31) in all coal-air ratio family curves carry out the biased sequence that combination of two calculates each combination respectively; For G ₁={ a ₁, a ₂a _n, G ₂={ b ₁, b ₂b _n, G ₁refer to the set that the numerical value that the n group of the first curve in combination is identical is formed, G ₂refer to the set that the numerical value that the n group of the second curve in combination is identical is formed; a ₁for the numerical value that corresponding i-th group of the first Curves in combination is identical, b ₁for the numerical value that corresponding i-th group of the second Curves in combination is identical, i gets 1 to n; If C _i=a _i-b _i,

Then biased sequence DEV _g1, _g2={ c ₁, c ₂c _n,

Next, if $\stackrel{\&OverBar;}{c}=\frac{1}{n}{\mathrm{\&Sigma;}}_{i=1}^n{c}_i,$ Then standard deviation

${\mathrm{\&sigma;}}_{{\mathrm{DEV}}_{G_1,G_2}}=\sqrt{\frac{1}{n-1}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{(c_i-\stackrel{\&OverBar;}{c})}^2}$

By each combination value arrange from small to large;

Finally, in above-mentioned arrangement, choose out by curve combination corresponding for the first two numerical value, then binding curve observes the coal pulverizer combination determined preferably.

Beneficial effect of the present invention is:

1) the present invention more adequately can provide the real time status of as-fired coal moisture as received coal, and measuring error is about 3%.

2) serve as theme with single coal-grinding kind-coal blending-mixed coal, in conjunction with coal mixing combustion concrete scheme, propose a set of general as-fired coal moisture as received coal on-line identification algorithm, can realize solving and classification judge the instantaneous value of each coal blending and mixed coal simultaneously.

3) when carrying out single coal-grinding kind moisture as received coal based on pulverized coal preparation system heat balance principle and solving, propose and be judged as main starting at conditional combination for characteristic parameter carries out single mill stable state with coal-air ratio, disintegrating outlet temperature, eliminate, owing to departing from pulverized coal preparation system thermal equilibrium state in mill increasing and decreasing load process, interference is produced to identification result, substantially increase the Stability and veracity of identification result;

4) solve on basis at single coal-grinding kind moisture as received coal, propose the method for optimizing that the coal-air ratio specificity analysis combined based on reality mill carries out coal blending and the combination of mixed coal mill, the powerful support real-time weighting process of coal blending and mixed coal moisture as received coal, improves accuracy and the reliability of final identification result.

5) as-fired coal matter metastable actual conditions within a short period of time are considered, when carrying out classification judge process, propose and processed by the get it right moisture as received coal of coal blending and mixed coal of filtering and fluctuometer, effectively eliminate the abnormal conditions of identification classification sudden change.

Accompanying drawing explanation

Fig. 1 is coal pulverizer heat balance system figure.

Fig. 2 is as-fired coal moisture as received coal identification algorithm process flow diagram.

Fig. 3 is as-fired coal moisture as received coal identification system composition frame chart.

Embodiment

Below according to Figure of description, in conjunction with the preferred embodiments technical scheme of the present invention is further described.

Current more than 300MW coal unit pulverized coal preparation system is generally equipped with 6 middling speed direct-blowing type coal mills, usually represents with A ~ F symbol, and when boiler fired coal is with design coal oepration at full load, five operations one are for subsequent use.For " stokehold blending, the coal blending of full storehouse ", the moisture as received coal of every platform mill all represents as-fired coal moisture as received coal; And for " point storehouse coal blending mixes burning in stove ", the moisture as received coal of every platform mill only represents the moisture as received coal that this mill grinds coal, as-fired coal moisture as received coal truly can only pass through combustion process concentrated expression.Based on above difference, we take following technical scheme to realize the object of the invention.

As shown in Figure 2, comprise the following steps based on pulverized coal preparation system thermally equilibrated as-fired coal moisture as received coal on-line identification method:

1) gather the online measuring point needed for identification model from real-time data base on the one hand by data-interface, and be that time window carries out running mean pre-service to reach the object of filtering real-time parameter ringing with 5min; Gather the information off-line needed for identification model from relational database on the other hand, comprise manual entry data, coal-air ratio Characterization Data, coal blending classification passes judgment on threshold data, mixed coal classification passes judgment on threshold data.

The coal mixing combustion scheme that power plant adopts for coal unit is divided into two kinds, in the first coal mixing combustion scheme, adopts: " stokehold blending, the coal blending of full storehouse "; In the second coal mixing combustion scheme, adopt: " point storehouse coal blending, mixes burning in stove ";

For the first coal mixing combustion scheme, the 1st coal pulverizer is mixed coal to the coal that M coal pulverizer grinds, and mixed coal is that coal is formed after blending; M gets 3 to 10; Now, the moisture as received coal of direct identification mixed coal; Example is as follows:

Identification coal	Actual mill combination
		Mixed coal	1st coal pulverizer is to the 6th coal pulverizer

For the second coal mixing combustion scheme, the Lower heat value of coal blending is V, and when V >=5000 kilocalorie, coal blending is high card coal; When 4500 kilocalories≤V<5000 kilocalorie, coal blending is middle card coal; When V<4500 kilocalorie, coal blending is low card coal; ; Obtain the kind of the coal blending that jth coal pulverizer grinds, determine the quantity of the often kind of coal blending needing identification, j gets 1 to M; Final realization is to the on-line identification of the moisture as received coal of often kind of coal blending and the moisture as received coal of mixed coal; Example is as follows:

Identification coal	Actual mill combination
		Mixed coal	1st coal pulverizer is to the 6th coal pulverizer
High card coal	1st coal pulverizer

Low card coal

2nd coal pulverizer is to the 6th coal pulverizer

2) arrange and start at the scope of application of condition to heat balance mechanism and retrain, for jth coal pulverizer, j gets 1 to M, arranges following three and starts at condition:

First condition of starting at is: the pulverized coal output B of jth coal pulverizer _m>=5.56Kg/s;

Second condition of starting at is: the entrance coal-air ratio g of jth coal pulverizer ₁meet 1.5≤g ₁≤ 3.5;

3rd condition of starting at is: for jth coal pulverizer, entrance coal-air ratio g ₁meet Sg. _{5min ± 5%}>=95%, and Sg. _{5min ± 2%}>=90%, meanwhile, outlet wind powder mixture temperature t ₂meet St. _{5min ± 5%}>=95% and St. _{5min ± 2%}>=90%;

Wherein, ${\mathrm{Sg}.}_{5\min .\&PlusMinus;5\%}=\frac{\mathrm{Ng}\&PlusMinus;5\%}{\mathrm{Ng}}\&times;100\%,{\mathrm{Sg}.}_{5\min .\&PlusMinus;2\%}=\frac{\mathrm{Ng}\&PlusMinus;2\%}{\mathrm{Ng}}\&times;100\%,$

Ng is the entrance coal-air ratio g calculating jth coal pulverizer in first 5 minutes of moment ₁historical data number, Ng _{± 5%}and Ng _{± 2%}computation process as follows: first, calculating first 5 minutes of moment in, calculate the entrance coal-air ratio g of jth coal pulverizer ₁the mean value of all historical datas, then, calculate the entrance coal-air ratio g of the jth coal pulverizer dropped in this mean value ± 5% scope ₁the number Ng of historical data _{± 5%}; Calculating drops on the entrance coal-air ratio g of the jth coal pulverizer in this mean value ± 2% scope ₁the number Ng of historical data _{± 2%};

${\mathrm{Sg}.}_{5\min .\&PlusMinus;5\%}=\frac{\mathrm{Ng}\&PlusMinus;5\%}{\mathrm{Nt}}\&times;100\%,{\mathrm{Sg}.}_{5\min .\&PlusMinus;2\%}=\frac{\mathrm{Ng}\&PlusMinus;2\%}{\mathrm{Nt}}\&times;100\%,$

Nt is the outlet wind powder mixture temperature t calculating jth coal pulverizer in first 5 minutes of moment ₂historical data number, Nt _{± 5%}and Nt _{± 2%}computation process as follows: first, calculating first 5 minutes of moment in, calculate the outlet wind powder mixture temperature t of jth coal pulverizer ₂the mean value of all historical datas, then, calculate the outlet wind powder mixture temperature t of the jth coal pulverizer dropped in this mean value ± 5% scope ₂the number Nt of historical data _{± 5%}; Calculating drops on the outlet wind powder mixture temperature t of the jth coal pulverizer in this mean value ± 2% scope ₂the number Nt of historical data _{± 2%};

Only have when above three conditions of starting at all meet, just solve the moisture as received coal m that jth coal pulverizer grinds coal _j; Otherwise, return and wait for that next computation period Resurvey data carry out starting at condition judgment; In the present invention, a computation period is set to 10s;

3) for the first coal mixing combustion scheme, step 4 is performed);

For the second coal mixing combustion scheme, for step 1) often kind of coal blending dividing, optimize coal pulverizer combination, coal pulverizer combination is made up of to the 3rd coal pulverizer the 1st coal pulverizer;

Example is as follows:

Sequence number	Identification coal	Actual mill combination	Preferred mill combination
				1	Mixed coal	1st coal pulverizer is to the 6th coal pulverizer
2	High card coal	1st coal pulverizer	1st coal pulverizer
				3	Low card coal	2nd coal pulverizer is to the 6th coal pulverizer	3rd coal pulverizer and the 4th coal pulverizer

After optimizing coal pulverizer combination, according to the moisture as received coal m of following formulae discovery coal blending _ar:

$m_{\mathrm{ar}}=\underset{i=1}{\overset{s}{\mathrm{\&Sigma;}}}(m_{\mathrm{ari}}\&times;\frac{B_{\mathrm{mi}}}{{\mathrm{\&Sigma;}}_{i=1}^s{B}_{\mathrm{mi}}})$

In above formula, m _arifor preferred i-th coal pulverizer grinds the moisture as received coal of coal, B _mifor the pulverized coal output of preferred i-th coal pulverizer, s is the quantity of the coal pulverizer optimized;

Classification judge is carried out to the moisture as received coal of coal blending, is described as follows:

When 0%<≤8%, the moisture as received coal of coal blending belongs to M1 classification; When 8%<≤12%, the moisture as received coal of coal blending belongs to M2 classification; When 12%<≤20%, the moisture as received coal of coal blending belongs to M3 classification; When 20%<≤100%, the moisture as received coal of coal blending belongs to M4 classification; According to " coal for power generation technical conditions ", as shown in the table:

Symbol	Coal	Lower limit	The upper limit
				M1	Low moisture coal	0％	8％
M2	Ordinary water divides coal	8％	12％
				M3	Ordinary water divides coal	12％	20％
M4	Hydrogenous coal	20％	100％

Obtain the generic of the moisture as received coal of last computation period coal blending, the historical data of the moisture as received coal of the coal blending then before the reading calculating moment in A1 minute, was the smoothing filtering of time window with A2 minute, obtains filtered data sequence; This data sequence is arranged by one group of data sequencing temporally; The span of A1 is 5 to 15; The span of A2 is 1-3;

According to the sequencing of time, following judgement is carried out to each data in this data sequence: when the data of in data sequence are between given zone, then judge in second at after this A3: in data sequence, whether have data to be between given zone all the time, if had, think coal blending the generic of moisture as received coal undergo mutation; Otherwise the generic maintaining the moisture as received coal of last computation period coal blending is constant; The span of A3 is 60 to 180;

Deterministic process between given zone is as follows: when the generic of the moisture as received coal of last computation period coal blending is M1 classification, is [8%+4%*A4,12%] between given zone; When the generic of the moisture as received coal of last computation period coal blending is M2 classification, be [0,8%-8%*A4] or [12%+8%*A4,20%] between given zone; When the generic of the moisture as received coal of last computation period coal blending is M3 classification, be [8%, 12%-4%*A4] or [20%+80%*A4,100%] between given zone; When the generic of the moisture as received coal of last computation period coal blending is M4 classification, between given zone be [12%, 20%-8%*A4]; The span of A4 is 20% to 30%;

4) for the first coal mixing combustion scheme, step 3) coal blending replace with mixed coal, then according to step 3), optimize mixed coal corresponding coal pulverizer combination, calculate the moisture as received coal of mixed coal, the generic of mixed coal passed judgment on;

For the second coal mixing combustion scheme, the coal pulverizer that often kind of coal blending optimizes is merged, thus define coal pulverizer combination corresponding to the mixed coal preferably, then step 3) coal blending replace with mixed coal, according to step 3) calculate the moisture as received coal of mixed coal, then the generic of mixed coal is passed judgment on.

Example is as follows:

Sequence number	Identification coal	Actual mill combination	Preferred mill combination
				1	Mixed coal	ABCDEF	ACD
2	High card coal	A	A
				3	Low card coal	BCDEF	CD

Each coal blending that on-line identification goes out and mixed coal moisture as received coal and classification evaluation result data, issue by B/S interface on the one hand and carry out refreshing in real time and query history trend, and comprehensively can analyze generating report forms report, DCS can be returned in addition and carry out closed optimized control, or be sent to the economic analysis application that SIS/MIS system carries out full level of factory

Described jth coal pulverizer grinds the moisture as received coal m of coal _jcomputation process as follows:

22)q _in＝q _ag1+q _mac+q _1e+q _s,

In above formula, q _ag1for the heat of jth coal pulverizer brought into by drying agent, q _macfor the heat that mechanical friction when jth coal pulverizer works adds, q _1efor jth coal pulverizer bleeds the physical thermal of cold air, q _sfor jth coal pulverizer sealing air physical thermal;

q _ag1＝g ₁×C _ag1×t ₁，

In above formula, g ₁for jth coal pulverizer inlet coal-air ratio, g ₁=m _f/ B _m; m _ffor jth coal pulverizer inlet First air flow, unit is kg/s; B _mfor the pulverized coal output of jth coal pulverizer, unit is kg/s; t ₁for jth coal pulverizer inlet First air temperature, unit is DEG C; C _ag1refer to when temperature is t ₁time drying agent average quality specific heat capacity, unit is kJ/ (kg DEG C);

q _mac＝K _mac×E _m，

In above formula, E _mfor the energy consumption of jth coal pulverizer, E _m=(U × I)/B _m; U is the voltage of jth coal pulverizer; I is the electric current of jth coal pulverizer; K _macfor jth coal pulverizer power input is converted into the coefficient of heat;

The mechanical thermal transformation ratio according to the form below of various types coal pulverizer is chosen;

Coal pulverizer pattern	Low speed coal mill	Medium-speed pulverizer	Blower mill
				Transformation ratio	0.7	0.6	0.8

q _1e＝K _1e×g ₁×C _1e×t _1e，

In above formula, K _1efor the air leakage coefficient of jth coal pulverizer, at pressurized direct pulverizing coal system, K _1e=0; t _1efor the air temperature of the jth coal pulverizer that bleeds, unit is DEG C; C _1erefer to when temperature is t _1etime soft air specific heat capacity, unit is kJ/ (kg DEG C);

When negative pressure pulverized coal preparation system, q _s=0, when other situations, q _s=(m _s/ B _m) × C _s× t _s, m _sfor the sealing air quantity of jth coal pulverizer, unit is kg/s; t _sfor the sealing air temperature of jth coal pulverizer, unit is DEG C; C _srefer to when temperature is t _stime soft air specific heat capacity, unit is kJ/ (kg DEG C);

23)q _out＝q _ev+q _ag2+q _f+q ₅；

In above formula, q _evfor the heat that the moisture evaporating coal consumes; q _ag2for the heat that drying agent is taken away; q _ffor adding the heat that hot coal consumes; q ₅for the radiation loss of coal unit pulverized coal preparation system;

q _ev＝△M×(2500+C _H2o×t ₂-4.187×t _rc)，

In above formula, the moisture that △ M loses for 1kg raw coal every in dry run;

△ M=(m _j-M _mf)/(100-M _mf); m _jfor jth coal pulverizer grinds the moisture as received coal of coal; M _mfor jth coal pulverizer outlet coal dust contained humidity;

M _mf=0.048 × m _j× R ₉₀/ t ₂ ^0.46; R ₉₀for fineness of pulverized coal; C _h2o is that water vapor average specific heat at constant pressure holds, and unit is kJ/ (kg DEG C); t _rcfor raw coal temperature, unit is DEG C); t ₂for jth coal pulverizer outlet wind powder mixture temperature;

q _ag2＝[(1+K _1e)×g ₁+(m _s/B _m)]×C _ag2×t _2,

In above formula, C _ag2refer to when temperature is t ₂time drying agent average quality specific heat capacity, unit is kJ/ (kg DEG C)

q _f＝(100-m _j)/100×[C _dc+(4.18×M _mf)/(100-M _mf)]×(t ₂-t _rc),

In above formula, C _dcfor the specific heat capacity of moisture-free coal, unit is kJ/ (kg DEG C);

For unit pulverized-coal system q ₅=0.02 × q _in,

For the ball type pulverizer system q ₅=0.05 × q _in,

The above-mentioned major parameter source related to is described as follows:

Sequence number	Parameter list	Source
			1	m f,B m,t le,t s,t 1,t 2U 1	On-line sampling system
2	K mac,K le,R 90,m s,t rc	Off-line typing constant
			3	C ag1,C ag2,,C H2o,C dc,C s,C le	To table look-up interpolation fitting

Note: the third line parameter is tabled look-up the finger average specific heat at constant pressure of gas " conventional hold "

24) simultaneous step 21), step 22) and step 23) formula, the moisture as received coal that jth coal pulverizer grinds coal can be calculated.

Described select coal pulverizer combination comprise the following steps:

31) for often kind of coal blending, according to step 1) obtain coal pulverizer corresponding to this kind of coal blending, corresponding coal pulverizer refers to: the coal pulverizer ground this kind of coal blending, choose these coal pulverizers historical data of first 3 months, when the coal-supplying amount of each coal pulverizer is greater than, round as horizontal ordinate downwards with the coal-supplying amount of this coal pulverizer, the identical numerical value of n group (the 1st group of numerical value that identical numerical value to the n-th group is identical) can be formed after different coal-supplying amounts rounds downwards, for often organizing identical numerical value, ask for the entrance coal-air ratio mean value of corresponding coal pulverizer, with this mean value for ordinate, draw the coal-air ratio family curve of each coal pulverizer respectively, this coal-air ratio family curve will upgrade in time and revise after coal pulverizer maintenance, the computation process of the entrance coal-air ratio mean value of the coal pulverizer under this coal-supplying amount is: after rounding downwards the coal-supplying amount of this coal pulverizer, averages to the entrance coal-air ratio of the coal pulverizer under identical coal-supplying amount,

32) for step 31) middle corresponding coal pulverizer, carry out the characteristic contrast of these coal pulverizer coal-air ratios, to be observed by curve and mathematical modeling judges that the mode combined finds out 2 ~ 3 curves be parallel to each other, then coal pulverizer corresponding for these curves is combined as the coal pulverizer after preferred.

The detailed process of described curve observation and mathematical modeling is as follows:

First by step 31) in all coal-air ratio family curves carry out, combination of two calculates the biased sequence of each combination respectively; For G ₁={ a ₁, a ₂a _n, G ₂={ b ₁, b ₂b _n, G ₁refer to the set that the numerical value that the n group of the first curve in combination is identical is formed, G ₂refer to the set that the numerical value that the n group of the second curve in combination is identical is formed; a ₁for the numerical value that corresponding i-th group of the first Curves in combination is identical, b ₁for the numerical value that corresponding i-th group of the second Curves in combination is identical, i gets 1 to n; If C _i=a _i-b _i,

Then biased sequence DEV _g1, _g2={ c ₁, c ₂c _n,

Next, if $\stackrel{\&OverBar;}{c}=\frac{1}{n}{\mathrm{\&Sigma;}}_{i=1}^n{c}_i,$ Then standard deviation

${\mathrm{\&sigma;}}_{{\mathrm{DEV}}_{G_1,G_2}}=\sqrt{\frac{1}{n-1}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{(c_i-\stackrel{\&OverBar;}{c})}^2}$

By each combination value arrange from small to large;

Finally, in above-mentioned arrangement, choose out by curve combination corresponding for the first two numerical value, then binding curve observes the coal pulverizer combination determined preferably.

Present system adopts B/S mode to realize, and be equipped with multiple servers and realize as-fired coal moisture as received coal on-line identification correlation function, Fig. 3 is the on-line identification block diagram of system, mainly comprises:

1) data-interface station: one side can realize data acquisition with DCS both-way communication and identification result returns, can transmit result data to other systems such as SIS, MIS on the other hand and be used for the application such as full level of factory economic analysis;

2) database server: for running real-time data base and relational database, stores historical data and the off-line analysis information of identification result.

3) identification calculation server: the identification online for real time execution identification algorithm model realization calculates, Mobile state of going forward side by side corrects to be optimized;

4) identification Analysis server: for based on the off-line analysis application in real time and on basis, history identification result storehouse, except being supported in line process, also can generating comprehensive identification analysis report and be used to guide production run;

5) report server: the day month year statistical report form for identification result data generates, can file for user's download and inquiry;

6) WEB publisher server: for identification result data B/S picture issue and system user mutual.

7) system management server: for management functions such as system user rights management, system maintenance, log recordings.

Claims (4)

1., based on pulverized coal preparation system thermally equilibrated as-fired coal moisture as received coal on-line identification method, it is characterized in that, comprise the following steps:

1) the coal mixing combustion scheme that power plant adopts for coal unit is divided into two kinds, in the first coal mixing combustion scheme, adopts: " stokehold blending, the coal blending of full storehouse "; In the second coal mixing combustion scheme, adopt: " point storehouse coal blending, mixes burning in stove ";

For the first coal mixing combustion scheme, the 1st coal pulverizer is mixed coal to the coal that M coal pulverizer grinds, and mixed coal is that coal is formed after blending; M gets 3 to 10;

For the second coal mixing combustion scheme, the Lower heat value of coal blending is V, and when V >=5000 kilocalorie, coal blending is high card coal; When 4500 kilocalories≤V<5000 kilocalorie, coal blending is middle card coal; When V<4500 kilocalorie, coal blending is low card coal; Obtain the kind of the coal blending that jth coal pulverizer grinds, determine the quantity of the often kind of coal blending needing identification, j gets 1 to M;

2) arrange and start at the scope of application of condition to heat balance mechanism and retrain, for jth coal pulverizer, j gets 1 to M, arranges following three and starts at condition:

First condition of starting at is: the pulverized coal output B of jth coal pulverizer _m>=5.56Kg/s;

Second condition of starting at is: the entrance coal-air ratio g of jth coal pulverizer ₁meet 1.5≤g ₁≤ 3.5;

3rd condition of starting at is: for jth coal pulverizer, entrance coal-air ratio g ₁meet Sg. _{5min ± 5%}>=95%, and Sg. _{5min ± 2%}>=90%, meanwhile, outlet wind powder mixture temperature t ₂meet St. _{5min ± 5%}>=95% and St. _{5min ± 2%}>=90%;

Wherein, ${\mathrm{Sg}.}_{5\min .\&PlusMinus;5\%}=\frac{{\mathrm{Ng}}_{\&PlusMinus;5\%}}{\mathrm{Ng}}\&times;100\%,{\mathrm{Sg}.}_{5\min .\&PlusMinus;2\%}=\frac{{\mathrm{Ng}}_{\&PlusMinus;2\%}}{\mathrm{Ng}}\&times;100\%,$ Ng is the entrance coal-air ratio g calculating jth coal pulverizer in first 5 minutes of moment ₁historical data number, Ng _{± 5%}and Ng _{± 2%}computation process as follows: first, calculating first 5 minutes of moment in, calculate the entrance coal-air ratio g of jth coal pulverizer ₁the mean value of all historical datas, then, calculate the entrance coal-air ratio g of the jth coal pulverizer dropped in this mean value ± 5% scope ₁the number Ng of historical data _{± 5%}; Calculating drops on the entrance coal-air ratio g of the jth coal pulverizer in this mean value ± 2% scope ₁the number Ng of historical data _{± 2%};

${\mathrm{St}.}_{5\min .\&PlusMinus;5\%}=\frac{{\mathrm{Nt}}_{\&PlusMinus;5\%}}{\mathrm{Nt}}\&times;100\%,{\mathrm{St}.}_{5\min .\&PlusMinus;2\%}=\frac{{\mathrm{Nt}}_{\&PlusMinus;2\%}}{\mathrm{Nt}}\&times;100\%,$

Nt is the outlet wind powder mixture temperature t calculating jth coal pulverizer in first 5 minutes of moment ₂historical data number, Nt _{± 5%}and Nt _{± 2%}computation process as follows: first, calculating first 5 minutes of moment in, calculate the outlet wind powder mixture temperature t of jth coal pulverizer ₂the mean value of all historical datas, then, calculate the outlet wind powder mixture temperature t of the jth coal pulverizer dropped in this mean value ± 5% scope ₂the number Nt of historical data _{± 5%}; Calculating drops on the outlet wind powder mixture temperature t of the jth coal pulverizer in this mean value ± 2% scope ₂the number Nt of historical data _{± 2%};

Only have when above three conditions of starting at all meet, just solve the moisture as received coal m that jth coal pulverizer grinds coal _j; Otherwise, return and wait for that next computation period Resurvey data carry out starting at condition judgment;

3) for the first coal mixing combustion scheme, step 4 is performed);

For the second coal mixing combustion scheme, for step 1) often kind of coal blending dividing, optimize coal pulverizer combination, coal pulverizer combination is made up of to the 3rd coal pulverizer the 1st coal pulverizer;

After optimizing coal pulverizer combination, according to the moisture as received coal m of following formulae discovery coal blending _ar:

$m_{\mathrm{ar}}=\underset{i=1}{\overset{s}{\mathrm{\&Sigma;}}}(m_{\mathrm{ari}}\&times;\frac{B_{\mathrm{mi}}}{{\mathrm{\&Sigma;}}_{i=1}^s{B}_{\mathrm{mi}}})$

In above formula, m _arifor preferred i-th coal pulverizer grinds the moisture as received coal of coal, B _mifor the pulverized coal output of preferred i-th coal pulverizer, s is the quantity of the coal pulverizer optimized;

To the moisture as received coal m of coal blending _arcarry out classification judge, be described as follows:

Work as 0%<m _arwhen≤8%, the moisture as received coal of coal blending belongs to M1 classification; Work as 8%<m _arwhen≤12%, the moisture as received coal of coal blending belongs to M2 classification; Work as 12%<m _arwhen≤20%, the moisture as received coal of coal blending belongs to M3 classification; Work as 20%<m _arwhen≤100%, the moisture as received coal of coal blending belongs to M4 classification;

Obtain the generic of the moisture as received coal of last computation period coal blending, the moisture as received coal m of the coal blending then before the reading calculating moment in A1 minute _arhistorical data, be the smoothing filtering of time window with A2 minute, obtain filtered data sequence; This data sequence is arranged by one group of data sequencing temporally; The span of A1 is 5 to 15; The span of A2 is 1-3;

According to the sequencing of time, following judgement is carried out to each data in this data sequence: when the data of in data sequence are between given zone, then judge in second at after this A3: in data sequence, whether have data to be between given zone all the time, if had, think coal blending the generic of moisture as received coal undergo mutation; Otherwise the generic maintaining the moisture as received coal of last computation period coal blending is constant; The span of A3 is 60 to 180;

Deterministic process between given zone is as follows: when the generic of the moisture as received coal of last computation period coal blending is M1 classification, is [8%+4%*A4,12%] between given zone; When the generic of the moisture as received coal of last computation period coal blending is M2 classification, be [0,8%-8%*A4] or [12%+8%*A4,20%] between given zone; When the generic of the moisture as received coal of last computation period coal blending is M3 classification, be [8%, 12%-4%*A4] or [20%+80%*A4,100%] between given zone; When the generic of the moisture as received coal of last computation period coal blending is M4 classification, between given zone be [12%, 20%-8%*A4]; The span of A4 is 20% to 30%;

4) for the first coal mixing combustion scheme, step 3) coal blending replace with mixed coal, then according to step 3), optimize mixed coal corresponding coal pulverizer combination, calculate the moisture as received coal of mixed coal, the generic of mixed coal passed judgment on;

For the second coal mixing combustion scheme, the coal pulverizer that often kind of coal blending optimizes is merged, thus define coal pulverizer combination corresponding to the mixed coal preferably, then step 3) coal blending replace with mixed coal, according to step 3) calculate the moisture as received coal of mixed coal, then the generic of mixed coal is passed judgment on.

2. according to claim 1 based on pulverized coal preparation system thermally equilibrated as-fired coal moisture as received coal on-line identification method, it is characterized in that, described jth coal pulverizer grinds the moisture as received coal m of coal _jcomputation process as follows:

21) the total amount of heat q of jth coal pulverizer is entered _inwith the total amount of heat q taking jth coal pulverizer out of _outidentical, i.e. q _in=q _out; With every kg coal for benchmark, carry out step 22) and step 23) calculating;

22)q _in＝q _ag1+q _mac+q _1e+q _s,

In above formula, q _ag1for the heat of jth coal pulverizer brought into by drying agent, q _macfor the heat that mechanical friction when jth coal pulverizer works adds, q _1efor jth coal pulverizer bleeds the physical thermal of cold air, q _sfor jth coal pulverizer sealing air physical thermal;

q _ag1＝g ₁×C _ag1×t ₁，

In above formula, g ₁for jth coal pulverizer inlet coal-air ratio, g ₁=m _f/ B _m; m _ffor jth coal pulverizer inlet First air flow, unit is kg/s; B _mfor the pulverized coal output of jth coal pulverizer, unit is kg/s; t ₁for jth coal pulverizer inlet First air temperature, unit is DEG C; C _ag1refer to when temperature is t ₁time drying agent average quality specific heat capacity, unit is kJ/ (kg DEG C)

q _mac＝K _mac×E _m

In above formula, E _mfor the energy consumption of jth coal pulverizer, E _m=(U × I)/B _m; U is the voltage of jth coal pulverizer; I is the electric current of jth coal pulverizer; K _macfor jth coal pulverizer power input is converted into the coefficient of heat;

q _1e＝K _1e×g ₁×C _1e×t _1e，

In above formula, K _1efor the air leakage coefficient of jth coal pulverizer, at pressurized direct pulverizing coal system, K _1e=0; t _1efor the air temperature of the jth coal pulverizer that bleeds, unit is DEG C; C _1erefer to when temperature is t _1etime soft air specific heat capacity, unit is kJ/ (kg DEG C);

When negative pressure pulverized coal preparation system, q _s=0, when other situations, q _s=(m _s/ B _m) × C _s× t _s, m _sfor the sealing air quantity of jth coal pulverizer, unit is kg/s; t _sfor the sealing air temperature of jth coal pulverizer, unit is DEG C; C _srefer to when temperature is t _stime soft air specific heat capacity, unit is kJ/ (kg DEG C);

23) q _out=q _ev+ q _ag2+ q _f+ q ₅; In above formula, q _evfor the heat that the moisture evaporating coal consumes; q _ag2for the heat that drying agent is taken away; q _ffor adding the heat that hot coal consumes; q ₅for the radiation loss of coal unit pulverized coal preparation system;

q _ev＝△M×(2500+C _H2o×t ₂-4.187×t _rc)

In above formula, the moisture that △ M loses for 1kg raw coal every in dry run;

△ M=(m _j-M _mf)/(100-M _mf); m _jfor jth coal pulverizer grinds the moisture as received coal of coal; M _mfor jth coal pulverizer outlet coal dust contained humidity;

M _mf=0.048 × m _j× R ₉₀/ t ₂ ^0.46; R ₉₀for fineness of pulverized coal; C _h2o is that water vapor average specific heat at constant pressure holds, and unit is kJ/ (kg DEG C); t _rcfor raw coal temperature, unit is DEG C); t ₂for jth coal pulverizer outlet wind powder mixture temperature;

q _ag2＝(1+K _1e)×g ₁+(m _s/B _m)×C _ag2×t ₂,

In above formula, C _ag2refer to when temperature is t ₂time drying agent average quality specific heat capacity, unit is kJ/ (kg DEG C)

q _f＝(100-m _j)/100×[C _dc+(4.18×M _mf)/(100-M _mf)]×(t ₂-t _rc),

In above formula, C _dcfor the specific heat capacity of moisture-free coal, unit is kJ/ (kg DEG C);

For unit pulverized-coal system q ₅=0.02 × q _in,

For the ball type pulverizer system q ₅=0.05 × q _in,

24) simultaneous step 21), step 22) and step 23) formula, the moisture as received coal m that jth coal pulverizer grinds coal can be calculated _j.

3. according to claim 1ly to it is characterized in that based on pulverized coal preparation system thermally equilibrated as-fired coal moisture as received coal on-line identification method, described in select coal pulverizer combination and comprise the following steps:

31) for often kind of coal blending, according to step 1) obtain coal pulverizer corresponding to this kind of coal blending, corresponding coal pulverizer refers to: the coal pulverizer ground this kind of coal blending, choose these coal pulverizers historical data of first 3 months, when the coal-supplying amount of each coal pulverizer is greater than 5.56kg/s, round as horizontal ordinate downwards with the coal-supplying amount of this coal pulverizer, the identical numerical value of n group can be formed after different coal-supplying amounts rounds downwards, for often organizing identical numerical value, ask for the entrance coal-air ratio mean value of corresponding coal pulverizer, with this mean value for ordinate, draw the coal-air ratio family curve of each coal pulverizer respectively, the computation process of the entrance coal-air ratio mean value of the coal pulverizer under this coal-supplying amount is: after rounding downwards the coal-supplying amount of this coal pulverizer, averages to the entrance coal-air ratio of the coal pulverizer under identical coal-supplying amount,

32) for step 31) middle corresponding coal pulverizer, carry out the characteristic contrast of these coal pulverizer coal-air ratios, to be observed by curve and mathematical modeling judges that the mode combined finds out 2 ~ 3 curves be parallel to each other, then coal pulverizer corresponding for these curves is combined as the coal pulverizer after preferred.

4. according to claim 3ly to it is characterized in that based on pulverized coal preparation system thermally equilibrated as-fired coal moisture as received coal on-line identification method, described curve observe and the detailed process of mathematical modeling as follows:

First by step 31) in all coal-air ratio family curves carry out the biased sequence that combination of two calculates each combination respectively; For G ₁={ a ₁, a ₂a _n, G ₂={ b ₁, b ₂b _n, G ₁refer to the set that the numerical value that the n group of the first curve in combination is identical is formed, G ₂refer to the set that the numerical value that the n group of the second curve in combination is identical is formed; a ₁for the numerical value that corresponding i-th group of the first Curves in combination is identical, b ₁for the numerical value that corresponding i-th group of the second Curves in combination is identical, i gets 1 to n; If C _i=a _i-b _i,

Then biased sequence DEV _g1, _g2={ c ₁, c ₂c _n,

Next, if $\stackrel{\&OverBar;}{C}=\frac{1}{n}{\mathrm{\&Sigma;}}_{i=1}^n{C}_i,$ Then standard deviation

${\mathrm{\&sigma;}}_{{\mathrm{DEV}}_{G_1,G_2}}=\sqrt{\frac{1}{n-1}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{(C_i-\stackrel{\&OverBar;}{C})}^2}$

By each combination value arrange from small to large;

Finally, in above-mentioned arrangement, choose out by curve combination corresponding for the first two numerical value, then binding curve observes the coal pulverizer combination determined preferably.