CN102645523A - 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

Go into stove coal as received basis moisture on-line discrimination method based on pulverized coal preparation system is thermally equilibrated

Technical field

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

Background technology

To the present situation of current " energy scarcity, market coal, plan ", coal in power plant shows as mostly originates various and ature of coal is changeable, and each item performance index of going into the stove coal are the off-design coal far away; On the other hand; Increasing power plant is through carrying out coal mixing combustion work enhancing efficiency by relying on tapping internal latent power; " stokehold blending; full storehouse coal blending " is that present two kinds of common main flows are mixed the burning mode with " divide the storehouse coal blending, mix burnings in the stove ", and the former is applicable to that the close situation of coal characteristic helps catching fire of coal dust and stablizing of burning; The latter be applied to more coal characteristic especially the grindability situation that differs greatly guaranteed rational fineness of pulverized coal and uniformity coefficient, the widespread use of coal mixing combustion makes the actual more complicated difficult control of fluctuation situation of going into the stove ature of coal.

To going into the monitoring of stove ature of coal; Power plant rests on the level of hand sampling, sample preparation, chemical examination basically at present; Exist serious lag and sampling error, thereby can't satisfy an urgent demand that operations staff's needs hold the operation of stove ature of coal situation optimization operation guidance in real time at all, therefore; On-line identification to ature of coal is the difficult point problem that needs to be resolved hurrily always, and application scenarios increasingly sophisticated also had higher requirement to this problem and challenge.

Go into stove coal as received basis moisture and be coal-fired main performance index, very big to the security and the economic influence of boiler operatiopn.Moisture as in the fire coal is higher, and the net heat of emitting when then burning reduces, and exhaust gas temperature raises, and boiler efficiency reduces, and the induced draft fan power consumption increases, and influences the pulverized coal preparation system drying and exerts oneself, and causes adverse consequencess such as cohering obstruction.The method that is used for fast measuring coal moisture at present has infrared method, conductance method, capacitance method, microwave method and neutron activation method etc.What wherein extensively adopt mainly is microwave method, and market share is more than 85%.Next is a capacitance method, market share about 12%.To going into the on-line identification of stove coal as received basis moisture, main through the instrument and equipment realization based on above-mentioned measuring principle is installed, the deficiency of this hard monitoring mode is:

1) hardware device costs an arm and a leg, and need take power plant's substantial contribution cost;

2) work under bad environment of power plant is had relatively high expectations to the accuracy and the durability of on-line monitoring instrument;

3) coal sample diffuse reflection that measurement result relied on or transmission signal very a little less than, situations such as the fineness of on-the-spot coal dust, bulk density thickness are very big to the influence of on-line monitoring result's accuracy.

4) to " divide the storehouse coal blending, mix burning in the stove " application scenarios, the equipment sampled point needs to change with mixing burning coal quantity, causes the system complex cost too high;

Along with the maturation of domestic real-time data base technology and soft-measuring technique in recent years; Part scholar utilizes the pulverized coal preparation system on-line measurement auxiliary variable and the off-line analysis information of storing in the real-time data base; Method through collection in worksite, flowsheeting, heat balance mechanism analysis or experimental test is carried out identification modeling, to solve the on-line identification problem of stove coal as received basis moisture.Though these flexible measurement methods have a clear superiority on fund cost than hard monitoring mode, tend to the theoretical research analysis more, the engineering practical application is few, lacks the comprehensive consideration to power plant's complex application context, does not form the complete on-line identification system of a cover.Weak point comprises:

1) indeterminate to the applicable elements scope of heat balance mechanism, do not consider the influence of actual condition fluctuation to the Theoretical Calculation result;

2) general is that object carries out the modeling of as received basis moisture and finds the solution with the separate unit mill only, does not consider that the overall treatments of many mill notional results are used;

3) do not combine the concrete coal mixing combustion scheme of power plant to carry out whole modeling analysis, can't realize on-line identification the as received basis moisture of each coal blending kind and mixed coal;

4) do not go into the judge analysis of stove coal as received basis moisture classification, only depend on the moisture instantaneous value that calculates generally to be difficult to directly apply in DCS closed-loop control, performance Index Calculation or the economic analysis.

Summary of the invention

The present invention is directed to above-mentioned defective discloses based on pulverized coal preparation system is thermally equilibrated and has gone into stove coal as received basis moisture on-line discrimination method.The present invention is based on the heat balance mechanism analysis of pulverized coal preparation system; Adopt the preferred complex optimum strategy of many mills; The coal mixing combustion mode of the coal-burning power plant's main flow of combining closely, provide a cover complete can reflect on-line identification system simultaneously into stove coal as received basis moisture instantaneous value and category feature.The present invention is applicable to the coal fired power generation unit.

Go into stove coal as received basis moisture on-line discrimination method and may further comprise the steps based on pulverized coal preparation system is thermally equilibrated:

1) power plant is divided into two kinds to the coal mixing combustion scheme that coal-fired unit adopted, and in first kind of coal mixing combustion scheme, adopts: " stokehold blending, full storehouse coal blending "; In second kind of coal mixing combustion scheme, adopt: " divide the storehouse coal blending, mix burning in the stove ";

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

For second kind of coal mixing combustion scheme, the Lower heat value of coal blending is V, and when V>=5000 kilocalories, coal blending is high card coal;<during 5000 kilocalories, coal blending is middle card coal as 4500 kilocalories≤V;<during 4500 kilocalories, coal blending is low card coal as V; 1 kilocalorie=4.185kJ/>kg; Obtain the kind of the coal blending that the j coal pulverizer grinds, need to confirm the quantity of every kind of coal blending of identification, j gets 1 to M;

2) for the j coal pulverizer, j gets 1 to M, is provided with following three and starts at condition:

First condition of starting at is: the coal-grinding of the j coal pulverizer B that exerts oneself _m>=5.56kg/s;

Second condition of starting at is: the inlet coal-air ratio g of j coal pulverizer ₁Satisfy 1.5≤g ₁≤3.5;

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

Wherein, ${\mathrm{Sg}}_{\&CenterDot;5\mathrm{Min}.\&PlusMinus;5\%}=\frac{{\mathrm{Ng}}_{\&PlusMinus;5\%}}{\mathrm{Ng}}\&times;100\%,$ ${\mathrm{Sg}}_{\&CenterDot;5\mathrm{Min}.\&PlusMinus;2\%}=\frac{{\mathrm{Ng}}_{\&PlusMinus;2\%}}{\mathrm{Ng}}\&times;100\%,$ Ng is the inlet coal-air ratio g of j coal pulverizer in preceding 5 minutes of the calculation time ₁The historical data number, Ng _{± 5%}And Ng _{± 2%}Computation process following: at first, in preceding 5 minutes of calculation time, calculate the inlet coal-air ratio g of j coal pulverizer ₁The mean value of all historical datas, then, calculate the inlet coal-air ratio g that drops on the j coal pulverizer in this mean value ± 5% scope ₁The number Ng of historical data _{± 5%}Calculating drops on the inlet coal-air ratio g of the j coal pulverizer in this mean value ± 2% scope ₁The number Ng of historical data _{± 2%}

${\mathrm{St}}_{\&CenterDot;5\mathrm{Min}.\&PlusMinus;5\%}=\frac{{\mathrm{Nt}}_{\&PlusMinus;5\%}}{\mathrm{Nt}}\&times;100\%,$ ${\mathrm{St}}_{\&CenterDot;5\mathrm{Min}.\&PlusMinus;2\%}=\frac{{\mathrm{Nt}}_{\&PlusMinus;2\%}}{\mathrm{Nt}}\&times;100\%,$ Nt is the outlet wind powder mixture temperature t of j coal pulverizer in preceding 5 minutes of the calculation time ₂The historical data number, Nt _{± 5%}And Nt _{± 2%}Computation process following: at first, in preceding 5 minutes of calculation time, calculate the outlet wind powder mixture temperature t of j coal pulverizer ₂The mean value of all historical datas, then, calculate the outlet wind powder mixture temperature t that drops on the j coal pulverizer 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 j coal pulverizer in this mean value ± 2% scope ₂The number Nt of historical data _{± 2%}

Have only when above three conditions of starting at all satisfy, just find the solution the as received basis moisture m that the j coal pulverizer grinds coal _jOtherwise, return wait for next computation period again image data start at condition judgment;

3) for first kind of coal mixing combustion scheme, execution in step 4);

For second kind of coal mixing combustion scheme, to every kind of coal blending that step 1) is divided, optimize the coal pulverizer combination, the coal pulverizer combination is made up of the 1st coal pulverizer to the 3 coal pulverizers;

After optimizing the coal pulverizer combination, calculate the as received basis moisture m of coal blending according to following formula _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 the following formula, m _AriFor preferred i coal pulverizer grinds the as received basis moisture of coal, B _MiFor the coal-grinding of preferred i coal pulverizer is exerted oneself, s is the quantity of the coal pulverizer that optimizes;

As received basis moisture m to coal blending _ArCarry out classification and pass judgment on, specify as follows:

When 0%<m _Ar≤8% o'clock, the as received basis moisture of coal blending belonged to the M1 classification; When 8%<m _Ar≤12% o'clock, the as received basis moisture of coal blending belonged to the M2 classification; When 12%<m _Ar≤20% o'clock, the as received basis moisture of coal blending belonged to the M3 classification; When 20%<m _Ar≤100% o'clock, the as received basis moisture of coal blending belonged to the M4 classification;

Obtain the affiliated classification of the as received basis moisture of last computation period coal blending, read the as received basis moisture m of the coal blending in A1 minute before the calculation time then _ArHistorical data, be that time window carries out smothing filtering with A2 minute, obtain filtered data sequence; This data sequence is to be arranged by the sequencing of time by one group of data to form; The span of A1 is 5 to 15; The span of A2 is 1-3;

The sequencing of each data in this data sequence according to the time carried out to judge: when data in the data sequence are between given zone; Then judge in second: whether have data to be between given zone in the data sequence all the time at A3 after this; If have, think coal blending the affiliated classification of as received basis moisture undergo mutation; Otherwise the affiliated classification of as received basis moisture of keeping last computation period coal blending is constant; The span of A4 is 20% to 30%;

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

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

For second kind of coal mixing combustion scheme; The coal pulverizer that every kind of coal blending is optimized merges; Thereby the coal pulverizer combination that the mixed coal after having formed preferably is corresponding; Replace with mixed coal to the coal blending of step 3) then, calculate the as received basis moisture of mixed coal, then the affiliated classification of mixed coal is passed judgment on according to step 3).

Said j coal pulverizer grinds the as received basis moisture m of coal _jComputation process following:

21) the total amount of heat q of entering j coal pulverizer _InWith the total amount of heat q that takes the j coal pulverizer out of _OutIdentical, i.e. q _In=q _OutWith every kg coal is benchmark, carry out step 22) and step 23) calculating;

22）q _in＝q _ag1+q _mac+q _le+q _s

In the following formula, q _Ag1For drying agent is brought the heat of j coal pulverizer, q into _MacThe heat that mechanical friction adds when being the work of j coal pulverizer, q _LeBe the bleed physics heat of cold air of j coal pulverizer, q _sBe j coal pulverizer sealing scenery reason heat.

q _ag1＝g ₁×C _ag1×t ₁，

In the following formula, g ₁Be j coal pulverizer inlet coal-air ratio, g ₁=m _f/ B _mm _fBe wind flow of j coal pulverizer inlet, unit is kg/s; B _mThe coal-grinding that is the j coal pulverizer is exerted oneself, and unit is kg/s; t ₁Be wind-warm syndrome degree of j coal pulverizer inlet, unit is ℃; C _Ag1Refer to that working as temperature is t ₁At present the average quality specific heat capacity of drying agent, unit is kJ/ (kg a ℃)

q _mac＝K _mac×E _m，

In the following formula, E _mBe the energy consumption of j coal pulverizer, E _m=(U * I)/B _mU is the voltage of j coal pulverizer; L is the electric current of j coal pulverizer; K _MacIt is the coefficient that j coal pulverizer power input is converted into heat;

q _le＝K _le×g ₁×C _le×t _le，

In the following formula, K _LeBe the air leakage coefficient of j coal pulverizer, at pressurized direct pulverizing coal system, K _Le=0; t _LeBe the cold air temperature of the j coal pulverizer that bleeds, unit is ℃; C _LeRefer to that working as temperature is t _LeThe time soft air specific heat capacity, unit is kJ/ (kg a ℃);

When the negative pressure pulverized coal preparation system, q _s=0, when other situation, q _s=(m _s/ B _m) * C _s* t _s, m _sBe the sealing air quantity of j coal pulverizer, unit is kg/s; t _sBe the sealing wind-warm syndrome degree of j coal pulverizer, unit is ℃; C _sRefer to that working as temperature is t _sThe time the soft air specific heat capacity, unit is kJ/ (kg a ℃);

23）q _out＝q _ev+q _ag2+q _f+q ₅；

In the following formula, q _EvThe heat that moisture consumed for the evaporation coal; q _Ag2The heat of taking away for drying agent; q _fFor adding the heat that hot coal consumes; q ₅Radiation loss for coal-fired unit pulverized coal preparation system;

$q_{\mathrm{ev}}=\mathrm{\&Delta;M}\&times;(2500+C_{H_{2}O}\&times;t_2-4.187\&times;t_{\mathrm{rc}})$

In the following formula, Δ M is the moisture that every 1kg raw coal is lost in the dry run;

Δ M=(m _j-M _Mf)/(100-M _Mf); m _jBe the as received basis moisture that the j coal pulverizer grinds coal; M _MfIt is j coal pulverizer outlet coal dust contained humidity;

M _Mf=0.048 * m _j* R ₉₀/ t ₂ ^0.46R ₉₀Be fineness of pulverized coal;

Be the average specific heat at constant pressure of water vapor, unit is kJ/ (kg a ℃); t _RcBe the raw coal temperature, unit is ℃); t ₂It is j coal pulverizer outlet wind powder mixture temperature;

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

In the following formula, C _Ag2Refer to that working as temperature is t ₂At present the average quality specific heat capacity of drying agent, unit is kJ/ (kg a ℃)

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

In the following formula, C _DcBe the specific heat capacity of moisture-free coal, unit is kJ/ (kg a ℃);

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, can calculate the as received basis moisture m that the j coal pulverizer grinds coal _j

Saidly select coal pulverizer combination and may further comprise the steps:

31) for every kind of coal blending, obtain the corresponding coal pulverizer of this kind coal blending according to step 1), corresponding coal pulverizer is meant: the coal pulverizer that coal blending grinds to this kind; Choose preceding 3 months historical data of these coal pulverizers; When the coal-supplying amount of each coal pulverizer during greater than 5.56kg/s, rounding downwards with the coal-supplying amount of this coal pulverizer is horizontal ordinate, can form the identical numerical value of n group after different coal-supplying amounts rounds downwards; For every group of identical numerical value; Asking for the inlet coal-air ratio mean value of corresponding coal pulverizer, is ordinate with this mean value, draws the coal-air ratio family curve of each coal pulverizer respectively; The computation process of the inlet coal-air ratio mean value of the coal pulverizer under this coal-supplying amount is: after the coal-supplying amount of this coal pulverizer is rounded downwards, the inlet coal-air ratio of the coal pulverizer under the identical coal-supplying amount is averaged;

32) for step 31) middle corresponding coal pulverizer; Carry out the characteristic contrast of these coal pulverizer coal-air ratios; Mode through curve is observed and the mathematical modeling judgement combines is found out 2～3 curves that are parallel to each other, and then the corresponding coal pulverizer of these curves is made up as the coal pulverizer after preferred.

The detailed process of said curve observation and mathematical modeling is following:

At first with step 31) in all coal-air ratio family curves carry out, biased sequence of each combination is calculated in combination in twos respectively; For G ₁={ a ₁, a ₂..., a _n, G ₂={ b ₁, b ₂..., b _n, G ₁Refer to the identical set that numerical value constituted of n group of first curve in the combination, G ₂Refer to the identical set that numerical value constituted of n group of second curve in the combination; a _iBe the identical numerical value of the pairing i group of first curve in the combination, b _iBe the identical numerical value of the pairing i group of second curve in the combination, i gets 1 to n; If c _i=a _i-b _i,

Biased sequence then ${\mathrm{DEV}}_{G_1,G_2}=\{c_1,c_2,...,c_n\}$

Secondly, establish $\stackrel{\&OverBar;}{c}=\frac{1}{n}{\mathrm{\&Sigma;}}_{i=1}^n{c}_i,$ Standard deviation then

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

The value of

of each combination is arranged from small to large;

At last, in above-mentioned arrangement, the curve combination that preceding two numerical value are corresponding is chosen out, and binding curve is observed the coal pulverizer combination after confirming preferably then.

Beneficial effect of the present invention is:

1) the present invention can give the real time status of the stove coal as received basis moisture of coming in and going out comparatively exactly, and measuring error is about 3%.

2) serve as theme with single coal-grinding kind-coal blending-mixed coal, in conjunction with the concrete scheme of coal mixing combustion, proposed a cover general go into stove coal as received basis moisture on-line identification algorithm, can realize simultaneously the instantaneous value of each coal blending and mixed coal is found the solution and the classification judge.

3) carrying out single coal-grinding kind as received basis moisture based on the pulverized coal preparation system heat balance principle when finding the solution; Proposed with coal-air ratio, to grind mouthful temperature be that characteristic parameter carries out single mill stable state and is judged as the main condition of starting at combination; Got rid of owing to depart from the pulverized coal preparation system thermal equilibrium state in the mill increasing and decreasing load process, improved the accuracy and the stability of identification result greatly identification result generation interference;

4) find the solution on the basis at single coal-grinding kind as received basis moisture; Proposed to carry out the method for optimizing of coal blending and the combination of mixed coal mill based on the coal-air ratio specificity analysis of reality mill combination; Support the real-time weighted of coal blending and mixed coal as received basis moisture effectively, improved the accuracy and the reliability of final identification result.

5) consider into stove ature of coal metastable actual conditions within a short period of time, carry out classification when pass judgment on handling, proposed to handle, effectively eliminated the abnormal conditions that the identification classification is suddenlyd change through the get it right as received basis moisture of coal blending and mixed coal of filtering and fluctuometer.

Description of drawings

Fig. 1 is coal pulverizer heat balance system figure

Fig. 2 is for going into stove coal as received basis moisture identification algorithm process flow diagram

Fig. 3 is for going into stove coal as received basis moisture identification system composition frame chart

Embodiment

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

6 middling speed direct-blowing type coal mills of the general outfit of coal-fired unit pulverized coal preparation system more than the 300MW are used A ~ F symbolic representation usually at present, and when boiler used the design coal oepration at full load, five one of operations were subsequent use.For " stokehold blending, full storehouse coal blending ", the as received basis moisture of every mill is all represented into stove coal as received basis moisture; And for " divide storehouse coal blending, mix burning in the stove ", on behalf of this mill, the as received basis moisture of every mill only grind the as received basis moisture of coal, going into stove coal as received basis moisture and can only pass through combustion process concentrated expression truly.Based on above difference, we take following technical scheme to realize the object of the invention.

As shown in Figure 2, go into stove coal as received basis moisture on-line discrimination method and may further comprise the steps based on pulverized coal preparation system is thermally equilibrated:

1) on the one hand gathers the required online measuring point of identification model through data-interface, and be that time window carries out the running mean pre-service to reach the purpose of filtering real-time parameter ringing with 5min from real-time data base; Gather the required information off-line of identification model from relational database on the other hand, comprise that manual entry data, coal-air ratio specificity analysis data, coal blending classification are passed judgment on threshold data, the mixed coal classification is passed judgment on threshold data.

Power plant is divided into two kinds to the coal mixing combustion scheme that coal-fired unit adopted, and in first kind of coal mixing combustion scheme, adopts: " stokehold blending, full storehouse coal blending "; In second kind of coal mixing combustion scheme, adopt: " divide the storehouse coal blending, mix burning in the stove ";

For first kind of coal mixing combustion scheme, the coal that the 1st coal pulverizer to the M coal pulverizer grinds is mixed coal, and mixed coal is that coal forms through after the blending; M gets 3 to 10; At this moment, directly the as received basis moisture of identification mixed coal gets final product; Example is following:

The identification coal	Actual mill combination
		Mixed coal	The 1st coal pulverizer to the 6 coal pulverizers

For second kind of coal mixing combustion scheme, the Lower heat value of coal blending is V, and when V>=5000 kilocalories, coal blending is high card coal;<during 5000 kilocalories, coal blending is middle card coal as 4500 kilocalories≤V;<during 4500 kilocalories, coal blending is low card coal as V; 1 kilocalorie=4.185kJ/>kg; Obtain the kind of the coal blending that the j coal pulverizer grinds, need to confirm the quantity of every kind of coal blending of identification, j gets 1 to M; The final on-line identification that realizes the as received basis moisture of the as received basis moisture of every kind of coal blending and mixed coal; Example is following:

The identification coal	Actual mill combination
		Mixed coal	The 1st coal pulverizer to the 6 coal pulverizers
High card coal	The 1st coal pulverizer
		Low card coal	The 2nd coal pulverizer to the 6 coal pulverizers

2) condition of starting at is set the scope of application of heat balance mechanism is retrained, for the j coal pulverizer, j gets 1 to M, is provided with following three and starts at condition:

First condition of starting at is: the coal-grinding of the j coal pulverizer B that exerts oneself _m>=5.56kg/s;

Second condition of starting at is: the inlet coal-air ratio g of j coal pulverizer ₁Satisfy 1.5≤g ₁≤3.5;

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

Wherein, ${\mathrm{Sg}}_{\&CenterDot;5\mathrm{Min}.\&PlusMinus;5\%}=\frac{{\mathrm{Ng}}_{\&PlusMinus;5\%}}{\mathrm{Ng}}\&times;100\%,$ ${\mathrm{Sg}}_{\&CenterDot;5\mathrm{Min}.\&PlusMinus;2\%}=\frac{{\mathrm{Ng}}_{\&PlusMinus;2\%}}{\mathrm{Ng}}\&times;100\%,$ Ng is the inlet coal-air ratio g of j coal pulverizer in preceding 5 minutes of the calculation time ₁The historical data number, Ng _{± 5%}And Ng _{± 2%}Computation process following: at first, in preceding 5 minutes of calculation time, calculate the inlet coal-air ratio g of j coal pulverizer ₁The mean value of all historical datas, then, calculate the inlet coal-air ratio g that drops on the j coal pulverizer in this mean value ± 5% scope ₁The number Ng of historical data _{± 5%}Calculating drops on the inlet coal-air ratio g of the j coal pulverizer in this mean value ± 2% scope ₁The number Ng of historical data _{± 2%}

${\mathrm{St}}_{\&CenterDot;5\mathrm{Min}.\&PlusMinus;5\%}=\frac{{\mathrm{Nt}}_{\&PlusMinus;5\%}}{\mathrm{Nt}}\&times;100\%,$ ${\mathrm{St}}_{\&CenterDot;5\mathrm{Min}.\&PlusMinus;2\%}=\frac{{\mathrm{Nt}}_{\&PlusMinus;2\%}}{\mathrm{Nt}}\&times;100\%,$ Nt is the outlet wind powder mixture temperature t of j coal pulverizer in preceding 5 minutes of the calculation time ₂The historical data number, Nt _{± 5%}And Nt _{± 2%}Computation process following: at first, in preceding 5 minutes of calculation time, calculate the outlet wind powder mixture temperature t of j coal pulverizer ₂The mean value of all historical datas, then, calculate the outlet wind powder mixture temperature t that drops on the j coal pulverizer 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 j coal pulverizer in this mean value ± 2% scope ₂The number Nt of historical data _{± 2%}

Have only when above three conditions of starting at all satisfy, just find the solution the as received basis moisture m that the j coal pulverizer grinds coal _jOtherwise, return wait for next computation period again image data start at condition judgment; In the present invention, a computation period is set to 10s;

3) for first kind of coal mixing combustion scheme, execution in step 4);

For second kind of coal mixing combustion scheme, to every kind of coal blending that step 1) is divided, optimize the coal pulverizer combination, the coal pulverizer combination is made up of the 1st coal pulverizer to the 3 coal pulverizers;

Example is following:

Sequence number	The identification coal	Actual mill combination	Preferred mill combination
				1	Mixed coal	The 1st coal pulverizer to the 6 coal pulverizers

2	High card coal	The 1st coal pulverizer	The 1st coal pulverizer
				3	Low card coal	The 2nd coal pulverizer to the 6 coal pulverizers	The 3rd coal pulverizer and the 4th coal pulverizer

After optimizing the coal pulverizer combination, calculate the as received basis moisture m of coal blending according to following formula _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 the following formula, m _AriFor preferred i coal pulverizer grinds the as received basis moisture of coal, B _MiFor the coal-grinding of preferred i coal pulverizer is exerted oneself, s is the quantity of the coal pulverizer that optimizes;

As received basis moisture m to coal blending _ArCarry out classification and pass judgment on, specify as follows:

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

Symbol	Coal	Lower limit	The upper limit
				M1	The 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 affiliated classification of the as received basis moisture of last computation period coal blending, read the as received basis moisture m of the coal blending in A1 minute before the calculation time then _ArHistorical data, be that time window carries out smothing filtering with A2 minute, obtain filtered data sequence; This data sequence is to be arranged by the sequencing of time by one group of data to form; The span of A1 is 5 to 15; The span of A2 is 1-3;

The sequencing of each data in this data sequence according to the time carried out to judge: when data in the data sequence are between given zone; Then judge in second: whether have data to be between given zone in the data sequence all the time at A3 after this; If have, think coal blending the affiliated classification of as received basis moisture undergo mutation; Otherwise the affiliated classification of as received basis moisture of keeping last computation period coal blending is constant; The span of A3 is 60 to 180;

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

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

For second kind of coal mixing combustion scheme; The coal pulverizer that every kind of coal blending is optimized merges; Thereby the coal pulverizer combination that the mixed coal after having formed preferably is corresponding; Replace with mixed coal to the coal blending of step 3) then, calculate the as received basis moisture of mixed coal, then the affiliated classification of mixed coal is passed judgment on according to step 3).

Example is following:

Sequence number	The identification coal	Actual mill combination	Preferred mill combination
				1	Mixed coal	A?B?C?D?E?F	A?C?D
2	High card coal	A	A
				3	Low card coal	B?C?D?E?F	C?D

Each coal blending that on-line identification goes out and mixed coal as received basis moisture and classification evaluation result data; Can refresh in real time and query history trend through the issue of B/S interface on the one hand; And can carry out the report of analysis-by-synthesis generation form; Can return in addition to DCS and carry out closed-loop optimization control, or be sent to the economic analysis application that the SIS/MIS system carries out full level of factory

Said j coal pulverizer grinds the as received basis moisture m of coal _jComputation process following:

21) as shown in Figure 1, coal pulverizer is the major equipment of pulverized coal preparation system, and for direct-firing MPS type medium-speed pulverizer, grind and the drying of raw coal are all carried out in coal pulverizer, according to the energy equilibrium and the mass balance principle of mill, gets into the total amount of heat q of j coal pulverizer _InWith the total amount of heat q that takes the j coal pulverizer out of _OutIdentical, i.e. q _In=q _OutWith every kg coal is benchmark, carry out step 22) and step 23) calculating;

22）q _in＝q _ag1+q _mac+q _le+q _s

In the following formula, q _Ag1For drying agent is brought the heat of j coal pulverizer, q into _MacThe heat that mechanical friction adds when being the work of j coal pulverizer, q _LeBe the bleed physics heat of cold air of j coal pulverizer, q _sBe j coal pulverizer sealing scenery reason heat.

q _ag1＝g ₁×C _ag1×t ₁，

In the following formula, g ₁Be j coal pulverizer inlet coal-air ratio, g ₁=m _f/ B _mm _fBe wind flow of j coal pulverizer inlet, unit is kg/s; B _mThe coal-grinding that is the j coal pulverizer is exerted oneself, and unit is kg/s; t ₁Be wind-warm syndrome degree of j coal pulverizer inlet, unit is ℃; C _Ag1Refer to that working as temperature is t ₁At present the average quality specific heat capacity of drying agent, unit is kJ/ (kg a ℃)

q _mac＝K _mac×E _m，

In the following formula, E _mBe the energy consumption of j coal pulverizer, E _m=(U * I)/B _mU is the voltage of j coal pulverizer; I is the electric current of j coal pulverizer; K _MacIt is the coefficient that j coal pulverizer power input is converted into heat;

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

The coal pulverizer pattern	Low speed coal mill	Medium-speed pulverizer	Blower mill
				Transformation ratio K mac	0.7	0.6	0.8

q _le＝K _le×g ₁×C _le×t _le，

In the following formula, K _LeBe the air leakage coefficient of j coal pulverizer, medium-speed pulverizer gets 0.1, at pressurized direct pulverizing coal system, and K _Le=0; t _LeBe the cold air temperature of the j coal pulverizer that bleeds, unit is ℃; C _LeRefer to that working as temperature is t _LeThe time soft air specific heat capacity, unit is kJ/ (kg a ℃);

When the negative pressure pulverized coal preparation system, q _s=0, when other situation, q _s=(m _s/ B _m) * C _s* t _s, m _sBe the sealing air quantity of j coal pulverizer, unit is kg/s; t _sBe the sealing wind-warm syndrome degree of j coal pulverizer, unit is ℃; C _sRefer to that working as temperature is t _sThe time the soft air specific heat capacity, unit is kJ/ (kg a ℃);

23)q _out＝q _ev+q _ag2+q _f+q ₅；

In the following formula, q _EvThe heat that moisture consumed for the evaporation coal; q _Ag2The heat of taking away for drying agent; q _fFor adding the heat that hot coal consumes; q ₅Radiation loss for coal-fired unit pulverized coal preparation system;

$q_{\mathrm{ev}}=\mathrm{\&Delta;M}\&times;(2500+C_{H_{2}O}\&times;t_2-4.187\&times;t_{\mathrm{rc}})$

In the following formula, Δ M is the moisture that every 1kg raw coal is lost in the dry run;

Δ M=(m _j-M _Mf)/(100-M _Mf); m _jBe the as received basis moisture that the j coal pulverizer grinds coal; M _MfIt is j coal pulverizer outlet coal dust contained humidity;

M _Mf=0.048 * m _j* R ₉₀/ t ₂ ^0.46R ₉₀Be fineness of pulverized coal, general desirable design load 20～25;

Be the average specific heat at constant pressure of water vapor, unit is kJ/ (kg a ℃); t _RcBe the raw coal temperature, unit is ℃); t ₂It is j coal pulverizer outlet wind powder mixture temperature;

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

In the following formula, C _Ag2Refer to that working as temperature is t ₂At present the average quality specific heat capacity of drying agent, unit is kJ/ (kg a ℃)

q _f=(100-m _j)/100 * (C _Dc+ (4.18 * M _Mf)/(100-M _Mf)) * (t ₂-t _Rc) in the following formula, C _DcBe the specific heat capacity of moisture-free coal, unit is kJ/ (kg a ℃);

For unit pulverized-coal system q ₅=0.02 * q _In

For the ball type pulverizer system q ₅=0.05 * q _In

Explain as follows in the above-mentioned major parameter source that relates to:

Annotate: the third line parameter fingers of tabling look-up " used the average specific heat at constant pressure C of gas always _{P, av}"

24) simultaneous step 21), step 22) and step 23) formula, can calculate the as received basis moisture m that the j coal pulverizer grinds coal _j

Saidly select coal pulverizer combination and may further comprise the steps:

31) for every kind of coal blending; Obtain the corresponding coal pulverizer of this kind coal blending according to step 1), corresponding coal pulverizer is meant: the coal pulverizer that coal blending grinds to this kind, choose preceding 3 months historical data of these coal pulverizers; When the coal-supplying amount of each coal pulverizer during greater than 5.56kg/s; Rounding downwards with the coal-supplying amount of this coal pulverizer is horizontal ordinate, can form the identical numerical value of n group (the 1st group of identical numerical value of identical numerical value to the n group) after different coal-supplying amounts rounds downwards, for every group of identical numerical value; Ask for the inlet coal-air ratio mean value of corresponding coal pulverizer; With this mean value is ordinate, draws the coal-air ratio family curve of each coal pulverizer respectively, and this coal-air ratio family curve will upgrade in time after the coal pulverizer maintenance and revise; The computation process of the inlet coal-air ratio mean value of the coal pulverizer under this coal-supplying amount is: after the coal-supplying amount of this coal pulverizer is rounded downwards, the inlet coal-air ratio of the coal pulverizer under the identical coal-supplying amount is averaged;

32) for step 31) middle corresponding coal pulverizer; Carry out the characteristic contrast of these coal pulverizer coal-air ratios; Mode through curve is observed and the mathematical modeling judgement combines is found out 2～3 curves that are parallel to each other, and then the corresponding coal pulverizer of these curves is made up as the coal pulverizer after preferred.

The detailed process of said curve observation and mathematical modeling is following:

At first with step 31) in all coal-air ratio family curves carry out, biased sequence of each combination is calculated in combination in twos respectively; For G ₁={ a ₁, a ₂..., a _n, G ₂={ b ₁, b ₂..., b _n, G ₁Refer to the identical set that numerical value constituted of n group of first curve in the combination, G ₂Refer to the identical set that numerical value constituted of n group of second curve in the combination; a _iBe the identical numerical value of the pairing i group of first curve in the combination, b _iBe the identical numerical value of the pairing i group of second curve in the combination, i gets 1 to n; If c _i=a _i-b _i,

Biased sequence then ${\mathrm{DEV}}_{G_1,G_2}=\{c_1,c_2,...,c_n\}$

Secondly, establish $\stackrel{\&OverBar;}{c}=\frac{1}{n}{\mathrm{\&Sigma;}}_{i=1}^n{c}_i,$ Standard deviation then

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

The value of

of each combination is arranged from small to large;

At last, in above-mentioned arrangement, the curve combination that preceding two numerical value are corresponding is chosen out, and binding curve is observed the coal pulverizer combination after confirming preferably then.

System of the present invention adopts the B/S mode to realize, is equipped with multiple servers and realizes that Fig. 3 is the on-line identification block diagram of system, mainly comprises into stove coal as received basis moisture on-line identification correlation function:

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

2) database server: be used to move real-time data base and relational database, the historical data and the off-line analysis information of storage identification result.

3) identification calculation server: be used for real time execution identification algorithm model and realize online identification calculating, and dynamically proofread and correct optimization;

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

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

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

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

Claims (4)

1. go into stove coal as received basis moisture on-line discrimination method based on pulverized coal preparation system is thermally equilibrated, it is characterized in that, may further comprise the steps:

1) power plant is divided into two kinds to the coal mixing combustion scheme that coal-fired unit adopted, and in first kind of coal mixing combustion scheme, adopts: " stokehold blending, full storehouse coal blending "; In second kind of coal mixing combustion scheme, adopt: " divide the storehouse coal blending, mix burning in the stove ";

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

For second kind of coal mixing combustion scheme, the Lower heat value of coal blending is V, and when V>=5000 kilocalories, coal blending is high card coal;<during 5000 kilocalories, coal blending is middle card coal as 4500 kilocalories≤V;<during 4500 kilocalories, coal blending is low card coal as V; 1 kilocalorie=4.185kJ/>kg; Obtain the kind of the coal blending that the j coal pulverizer grinds, need to confirm the quantity of every kind of coal blending of identification, j gets 1 to M;

2) condition of starting at is set the scope of application of heat balance mechanism is retrained, for the j coal pulverizer, j gets 1 to M, is provided with following three and starts at condition:

First condition of starting at is: the coal-grinding of the j coal pulverizer B that exerts oneself _m>=5.56kg/s;

Second condition of starting at is: the inlet coal-air ratio g of j coal pulverizer ₁Satisfy 1.5≤g ₁≤3.5;

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

Wherein, ${\mathrm{Sg}}_{\&CenterDot;5\mathrm{Min}.\&PlusMinus;5\%}=\frac{{\mathrm{Ng}}_{\&PlusMinus;5\%}}{\mathrm{Ng}}\&times;100\%,$ ${\mathrm{Sg}}_{\&CenterDot;5\mathrm{Min}.\&PlusMinus;2\%}=\frac{{\mathrm{Ng}}_{\&PlusMinus;2\%}}{\mathrm{Ng}}\&times;100\%,$ Ng is the inlet coal-air ratio g of j coal pulverizer in preceding 5 minutes of the calculation time ₁The historical data number, Ng _{± 5%}And Ng _{± 2%}Computation process following: at first, in preceding 5 minutes of calculation time, calculate the inlet coal-air ratio g of j coal pulverizer ₁The mean value of all historical datas, then, calculate the inlet coal-air ratio g that drops on the j coal pulverizer in this mean value ± 5% scope ₁The number Ng of historical data _{± 5%}Calculating drops on the inlet coal-air ratio g of the j coal pulverizer in this mean value ± 2% scope ₁The number Ng of historical data _{± 2%}

${\mathrm{St}}_{\&CenterDot;5\mathrm{Min}.\&PlusMinus;5\%}=\frac{{\mathrm{Nt}}_{\&PlusMinus;5\%}}{\mathrm{Nt}}\&times;100\%,$ ${\mathrm{St}}_{\&CenterDot;5\mathrm{Min}.\&PlusMinus;2\%}=\frac{{\mathrm{Nt}}_{\&PlusMinus;2\%}}{\mathrm{Nt}}\&times;100\%,$ N _tOutlet wind powder mixture temperature t for j coal pulverizer in preceding 5 minutes of the calculation time ₂The historical data number, Nt _{± 5%}And Nt _{± 2%}Computation process following: at first, in preceding 5 minutes of calculation time, calculate the outlet wind powder mixture temperature t of j coal pulverizer ₂The mean value of all historical datas, then, calculate the outlet wind powder mixture temperature t that drops on the j coal pulverizer 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 j coal pulverizer in this mean value ± 2% scope ₂The number Nt of historical data _{± 2%}

Have only when above three conditions of starting at all satisfy, just find the solution the as received basis moisture m that the j coal pulverizer grinds coal _jOtherwise, return wait for next computation period again image data start at condition judgment;

3) for first kind of coal mixing combustion scheme, execution in step 4);

For second kind of coal mixing combustion scheme, to every kind of coal blending that step 1) is divided, optimize the coal pulverizer combination, the coal pulverizer combination is made up of the 1st coal pulverizer to the 3 coal pulverizers;

After optimizing the coal pulverizer combination, calculate the as received basis moisture m of coal blending according to following formula _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 the following formula, m _AriFor preferred i coal pulverizer grinds the as received basis moisture of coal, B _MiFor the coal-grinding of preferred i coal pulverizer is exerted oneself, s is the quantity of the coal pulverizer that optimizes;

As received basis moisture m to coal blending _ArCarry out classification and pass judgment on, specify as follows:

When 0%<m _Ar≤8% o'clock, the as received basis moisture of coal blending belonged to the M1 classification; When 8%<m _Ar≤12% o'clock, the as received basis moisture of coal blending belonged to the M2 classification; When 12%<m _Ar≤20% o'clock, the as received basis moisture of coal blending belonged to the M3 classification; When 20%<m _Ar≤100% o'clock, the as received basis moisture of coal blending belonged to the M4 classification;

Obtain the affiliated classification of the as received basis moisture of last computation period coal blending, read the as received basis moisture m of the coal blending in A1 minute before the calculation time then _ArHistorical data, be that time window carries out smothing filtering with A2 minute, obtain filtered data sequence; This data sequence is to be arranged by the sequencing of time by one group of data to form; The span of A1 is 5 to 15; The span of A2 is 1-3;

The sequencing of each data in this data sequence according to the time carried out to judge: when data in the data sequence are between given zone; Then judge in second: whether have data to be between given zone in the data sequence all the time at A3 after this; If have, think coal blending the affiliated classification of as received basis moisture undergo mutation; Otherwise the affiliated classification of as received basis moisture of keeping last computation period coal blending is constant; The span of A3 is 60 to 180;

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

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

For second kind of coal mixing combustion scheme; The coal pulverizer that every kind of coal blending is optimized merges; Thereby the coal pulverizer combination that the mixed coal after having formed preferably is corresponding; Replace with mixed coal to the coal blending of step 3) then, calculate the as received basis moisture of mixed coal, then the affiliated classification of mixed coal is passed judgment on according to step 3).

2. according to claim 1ly go into stove coal as received basis moisture on-line discrimination method, it is characterized in that said j coal pulverizer grinds the as received basis moisture m of coal based on pulverized coal preparation system is thermally equilibrated _jComputation process following:

21) the total amount of heat q of entering j coal pulverizer _InWith the total amount of heat q that takes the j coal pulverizer out of _OutIdentical, i.e. q _In=q _OutWith every kg coal is benchmark, carry out step 22) and step 23) calculating;

22）q _in＝q _ag1+q _mac+q _le+q _s

In the following formula, q _Ag1For drying agent is brought the heat of j coal pulverizer, q into _MacThe heat that mechanical friction adds when being the work of j coal pulverizer, q _LeBe the bleed physics heat of cold air of j coal pulverizer, q _sBe j coal pulverizer sealing scenery reason heat;

q _ag1＝g ₁×C _ag1×t ₁，

In the following formula, g ₁Be j coal pulverizer inlet coal-air ratio, g ₁=m _f/ B _mm _fBe wind flow of j coal pulverizer inlet, unit is kg/s; B _mThe coal-grinding that is the j coal pulverizer is exerted oneself, and unit is kg/s; t ₁Be wind-warm syndrome degree of j coal pulverizer inlet, unit is ℃; C _Ag1Refer to that working as temperature is t ₁At present the average quality specific heat capacity of drying agent, unit is kJ/ (kg a ℃)

q _mac＝K _mac×E _m，

In the following formula, E _mBe the energy consumption of j coal pulverizer, E _m=(U * I)/B _mU is the voltage of j coal pulverizer; I is the electric current of j coal pulverizer; K _MacIt is the coefficient that j coal pulverizer power input is converted into heat;

q _le＝K _le×g ₁×C _le×t _le，

In the following formula, K _LeBe the air leakage coefficient of j coal pulverizer, at pressurized direct pulverizing coal system, K _Le=0; t _LeBe the cold air temperature of the j coal pulverizer that bleeds, unit is ℃; C _LeRefer to that working as temperature is t _LeThe time soft air specific heat capacity, unit is kJ/ (kg a ℃);

When the negative pressure pulverized coal preparation system, q _s=0, when other situation, q _s=(m _s/ B _m) * C _s* t _s, m _sBe the sealing air quantity of j coal pulverizer, unit is kg/s; t _sBe the sealing wind-warm syndrome degree of j coal pulverizer, unit is ℃; C _sRefer to that working as temperature is t _sThe time the soft air specific heat capacity, unit is kJ/ (kg a ℃);

23）q _out＝q _ev+q _ag2+q _f+q ₅；

In the following formula, q _EvThe heat that moisture consumed for the evaporation coal; q _Ag2The heat of taking away for drying agent; q _fFor adding the heat that hot coal consumes; q ₅Radiation loss for coal-fired unit pulverized coal preparation system;

$q_{\mathrm{ev}}=\mathrm{\&Delta;M}\&times;(2500+C_{H_{2}O}\&times;t_2-4.187\&times;t_{\mathrm{rc}})$

In the following formula, Δ M is the moisture that every 1kg raw coal is lost in the dry run;

Δ M=(m _j-M _Mf)/(100-M _Mf); m _jBe the as received basis moisture that the j coal pulverizer grinds coal; M _MfIt is j coal pulverizer outlet coal dust contained humidity;

M _Mf=0.048 * m _j* R ₉₀/ t ₂ ^0.46R ₉₀Be fineness of pulverized coal; Be the average specific heat at constant pressure of water vapor, unit is kJ/ (kg a ℃); t _RcBe the raw coal temperature, unit is ℃); t ₂It is j coal pulverizer outlet wind powder mixture temperature;

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

In the following formula, C _Ag2Refer to that working as temperature is t ₂At present the average quality specific heat capacity of drying agent, unit is kJ/ (kg a ℃)

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

In the following formula, C _DcBe the specific heat capacity of moisture-free coal, unit is kJ/ (kg a ℃);

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, can calculate the as received basis moisture m that the j coal pulverizer grinds coal _j

3. according to claim 1ly go into stove coal as received basis moisture on-line discrimination method, it is characterized in that, saidly select the coal pulverizer combination and may further comprise the steps based on pulverized coal preparation system is thermally equilibrated:

31) for every kind of coal blending, obtain the corresponding coal pulverizer of this kind coal blending according to step 1), corresponding coal pulverizer is meant: the coal pulverizer that coal blending grinds to this kind; Choose preceding 3 months historical data of these coal pulverizers; When the coal-supplying amount of each coal pulverizer during greater than 5.56kg/s, rounding downwards with the coal-supplying amount of this coal pulverizer is horizontal ordinate, can form the identical numerical value of n group after different coal-supplying amounts rounds downwards; For every group of identical numerical value; Asking for the inlet coal-air ratio mean value of corresponding coal pulverizer, is ordinate with this mean value, draws the coal-air ratio family curve of each coal pulverizer respectively; The computation process of the inlet coal-air ratio mean value of the coal pulverizer under this coal-supplying amount is: after the coal-supplying amount of this coal pulverizer is rounded downwards, the inlet coal-air ratio of the coal pulverizer under the identical coal-supplying amount is averaged;

32) for step 31) middle corresponding coal pulverizer; Carry out the characteristic contrast of these coal pulverizer coal-air ratios; Mode through curve is observed and the mathematical modeling judgement combines is found out 2 ~ 3 curves that are parallel to each other, and then the corresponding coal pulverizer of these curves is made up as the coal pulverizer after preferred.

4. according to claim 3ly go into stove coal as received basis moisture on-line discrimination method, it is characterized in that based on pulverized coal preparation system is thermally equilibrated, said curve observe and the detailed process of mathematical modeling following:

At first with step 31) in all coal-air ratio family curves carry out, biased sequence of each combination is calculated in combination in twos respectively; For G ₁={ a ₁, a ₂..., a _n, G ₂={ b ₁, b ₂..., b _n, G ₁Refer to the identical set that numerical value constituted of n group of first curve in the combination, G ₂Refer to the identical set that numerical value constituted of n group of second curve in the combination; a _iBe the identical numerical value of the pairing i group of first curve in the combination, b _iBe the identical numerical value of the pairing i group of second curve in the combination, i gets 1 to n; If c _i=a _i-b _i,

Biased sequence then ${\mathrm{DEV}}_{G_1,G_2}=\{c_1,c_2,...,c_n\}$

Secondly, establish $\stackrel{\&OverBar;}{c}=\frac{1}{n}{\mathrm{\&Sigma;}}_{i=1}^n{c}_i,$ Standard deviation then

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

The value of

of each combination is arranged from small to large;

At last, in above-mentioned arrangement, the curve combination that preceding two numerical value are corresponding is chosen out, and binding curve is observed the coal pulverizer combination after confirming preferably then.

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