CN101446417B - Boiler water-cooling wall high-temperature corrosion on-line monitoring device and method thereof - Google Patents

Abstract

The invention provides a boiler water wall high-temperature corrosion on-line monitoring device and a method thereof. The device comprises a flue gas sampling pipe, a flue gas analyzer, an industrial computer, a high temperature thermocouple and a monitor. The method comprises the following steps: opening holes of the connection plate between the pipes on the membrane water wall; arranging 1 to 5layers of measuring points in the height direction of a furnace; sucking flue gas by the flue gas sampling pipe; measuring the concentrations of CO, O2 and SO2 in the flue gas by the flue gas analyzer; and measuring the wall temperature of the wall of the water wall by combining the high temperature thermocouple; and transmitting the measured data to the industrial computer. Meanwhile, the industrial computer receives the data of the primary air speed, the secondary air speed and the air powder concentration of the Oracle database of the MIS system of a power plant, analyzes by modified intangible analytical hierarchy process, calculates the weight of the prior high-temperature corrosion influencing factor, carries out ordering on a real-time basis according to the weight, display the result on the picture of the monitor in a user-friendly manner, and gives a relevant diagnosis suggestion, and requires the line personnel to adjust timely.

Description

A kind of apparatus and method of on-line monitoring boiler water-cooling wall high-temperature corrosion

Technical field

The invention belongs to the boiler combustion diagnostic field, closely related with safe operation of the boiler, be specifically related to a kind of apparatus and method of on-line monitoring boiler water-cooling wall high-temperature corrosion.

Background technology

At present, all there is the situation of Actual combustion coal off-design coal in the most power plant of China, for coal resource anxiety or price reasons, mix the burning small coal mine nearby, come any coal to burn what coal, coal changes greatly and is frequent, after particularly the higher coal of sulfur content is gone into stove, causes the boiler tube wall high temperature corrosion, the quick-fried leakage of aggravation boiler tube, directly endanger safe operation of the boiler, this trend is on big capacity unit, and is particularly remarkable.

For the mechanism of high temperature corrosion, existing both at home and abroad a large amount of comparatively deep researchs.At oil exploration, exploitation and chemical field the high temperature corrosion checkout gear is arranged, but fail to realize on-line monitoring.The device that more finds no the on-line monitoring high temperature corrosion is applied to the report of station boiler.Usually, station boiler high temperature corrosion problem all is during major overhaul, finds when checking tube wall that therefore, when pinpointing the problems, high temperature corrosion has taken place tube wall, can't point out operation or maintainer in time to take measures, and causes the tremendous economic loss to power plant.

Below be retrieve with the closely-related document of the present invention:

Patent CN1506616A has proposed a kind of method of discrimination of water wall high temperature corrosion degree, this method determines to influence the principal element of water wall high temperature corrosion earlier, determine measuring condition then, measuring respectively has related parameter, adopts grey clustering method that the water wall high temperature corrosion tendency is carried out multifactorial evaluation at last.

Patent CN1657825A has proposed a kind of boiler plant that prevents the burner wall formula layout of water wall high temperature corrosion and slagging scorification, and the adjustment of arranging by boiler structure prevents high temperature corrosion.

Patent CN101021315A has proposed a kind of low NOx vortex burning device that prevents high temperature corrosion, prevents high temperature corrosion by improving burner.

Oil instrument .2005,19 (5) documents " development of the dynamic corrosion tester of SCM Based HTHP " to have introduced what be used for field of petroleum exploitation be the dynamic corrosion tester of HTHP that core constitutes with the single-chip microcomputer, specifically set forth the test philosophy of corrosion rate, the tester structural design, the temperature of dynamic corrosion tester, rotating speed control etc.

Unit is in big capacity, the evolution of high parameter direction, because it is limited that the sectional dimension of burner hearth increases, and the heat of sending into burner hearth increases greatly, cause furnace cross to increase considerably, burner region water-cooling wall temperature is too high, has accelerated the speed of high temperature corrosion, when wall temperature in 400-500 ℃ of scope, 50 ℃ of the every increases of wall temperature, corrosion rate doubles.

High temperature corrosion is relevant with the operation adjustment, for DC burner, and near the unreasonable anoxic of water-cooling wall wall that causes of air distribution, reducing atmosphere occurs, the aggravation high temperature corrosion is for turbulent burner, the excessive uncombusted coal dust that easily causes of swirl strength washes away water-cooling wall, causes the tube wall high temperature corrosion.

In addition, the SO that also generates when the stove internal combustion with coal dust of high temperature corrosion ₂, SO ₃Deng sour gas direct relation is arranged, these sour gas are penetrated into the tube wall metal surface, and corrosion reaction takes place, and destroy water-cooling wall.In addition, make the metal surface easily generate loose porous FeO, in the anoxic reducing atmosphere, generate a large amount of H during the high-sulfur pulverized coal friring because the interior local anoxic of stove increases temperature ₂S, H ₂The oxide-film reaction of S and water-cooling wall is also adsorbed various corrosive gas, quickens high temperature corrosion.Because H ₂S and CO concentration are linear, so H ₂S content can characterize by CO content, if can be to CO concentration, SO near the water-cooling wall ₂Concentration and water-cooling wall wall temperature carry out on-line monitoring, and control these parameters at zone of reasonableness by operation adjustment, just can guarantee that the probability of water wall high temperature corrosion reduces greatly.

Summary of the invention

The object of the present invention is to provide a kind of apparatus and method of on-line monitoring boiler water-cooling wall high-temperature corrosion.

For achieving the above object, the present invention is along the furnace height direction, between water-cooling wall wall pipe on the connecting plate, offer the hole that the 1-5 layer is connected with the flue gas sampling pipe, the flue gas sampling pipe stretches into burner hearth by perforate and extracts flue gas, the flue gas sampling pipe links to each other with industrial computer by flue gas analyzer, and on the water-cooling wall wall, also be provided with the pyrometer couple that is used to measure the water-cooling wall wall surface temperature, pyrometer couple is transferred to industrial computer with the temperature of the water-cooling wall wall that records, industrial computer receives primary air velocity in power plant's mis system oracle database simultaneously, pulverized-coal concentration, the secondary wind speed service data, the output of industrial computer 5 also is connected with display.

In order to find maximum influence factor from numerous influence factors, the present invention adopts improved Fuzzy AHP to carry out analyzing and processing, and its concrete steps are as follows:

1) determine with high temperature corrosion A to be destination layer, with operation factor B1, atmosphere field B2 is a rule layer, and pulverized-coal concentration C1, water-cooling wall wall temperature C2, primary air velocity C3, secondary wind speed C4 are the factor layer under the rule layer operation factor B1 correspondence, wall O ₂Concentration C 5, CO concentration C 6, SO ₂Concentration C 7 is the factor layer under the B2 correspondence of rule layer atmosphere field, sets up the pairing high temperature corrosion hierarchy Model of each layer measuring point;

2) be benchmark with unit respective design parameter, formulate the metering weighted list;

3) establish the rule layer Fuzzy consistent matrix: it is identical to the high temperature corrosion influence degree with atmosphere field B2 to look operation factor B1, and the rule layer Fuzzy consistent matrix is taken as: $\left[\begin{array}{cc}0.5& 0.5\\ 0.5& 0.5\end{array}\right];$

4) establish the Fuzzy consistent matrix of factor layer, and carry out the crash consistency check

According to the metering weight of measurement index, making the shared metering weight of i kind factor is x, and the shared metering weight of j kind factor is y, then by formula r _Ij=x-y+0.5 calculates the relative weighting factor of structure Fuzzy consistent matrix, structural factor layer Fuzzy consistent matrix, and carry out consistency check;

The consistency check principle is: any nominated bank of matrix and the corresponding difference of all the other each row are some constants; If do not satisfy consistency check, then by formula: $r_{\mathrm{ij}}=\frac{1}{n}\underset{k=1}{\overset{n}{\mathrm{\Σ}}}(r_{\mathrm{ik}}-r_{\mathrm{jk}}+0.5),1\≤i,j\≤n,$ N is a matrix dimension, to r _IjRecomputate, re-construct Fuzzy consistent matrix;

5) by formula $w_i=\frac{1}{n}-\frac{1}{2a}+\frac{1}{\mathrm{na}}\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{r}_{\mathrm{ij}},$ $(a\≥\frac{n-1}{2}),$ Calculate actual weight vector w _i, the factor layer actual weight that the actual weight value of rule layer is corresponding with these standards layer multiplies each other, and obtains total ordering of final each factor, finds out the factor that high temperature corrosion is had the greatest impact, if final CO concentration, SO ₂Concentration or the ordering of water-cooling wall temperature are forward, and CO concentration, SO are described ₂Concentration and water-cooling wall temperature height, industrial computer will instruct this zone to strengthen secondary air flow and suitably reduce the coal dust input amount, to reduce CO concentration, SO ₂Concentration and water-cooling wall temperature reduce the adverse effect to high temperature corrosion.

Apparatus of the present invention extract flue gas by the flue gas sampling pipe, record CO in the flue gas, O through flue gas analyzer ₂And SO ₂Three kinds of gas concentrations, and, arrive industrial computer recording transfer of data in conjunction with the water-cooling wall wall temperature that pyrometer couple records.Simultaneously, industrial computer receives primary air velocity, secondary wind speed and pulverized-coal concentration data in power plant's mis system oracle database, utilize improved Fuzzy AHP to carry out Treatment Analysis, calculate the weight size of current high temperature corrosion influence factor, and sort in real time according to the weight size, instruct the operation of boiler according to ranking results.The present invention is directed to the present situation of ature of coal frequent variations, realized the on-line monitoring boiler water-cooling wall high-temperature corrosion, make the operations staff scientific, visual understanding be arranged stove internal combustion state.

Description of drawings

Fig. 1 is apparatus of the present invention schematic diagrams

Fig. 2 is the probe tube schematic diagram;

Fig. 3 is a hierarchical chart of the present invention.

Wherein label is represented respectively:

1. water-cooling wall wall, 2. flue gas sampling pipe, 3. pyrometer couple, 4. flue gas analyzer, 5. industrial computer, 6.Oracle database, 7. display, 8. water screen tube, 9. connecting plate between water screen tube

The specific embodiment

Below in conjunction with specific embodiment the present invention is described in further detail.

Referring to Fig. 1, the present invention is along the furnace height direction, offer the hole that the 1-5 layer is connected with flue gas sampling pipe 2 between water-cooling wall wall 1 pipe on the connecting plate 9, flue gas sampling pipe 2 stretches into burner hearth by perforate and extracts flue gas, flue gas sampling pipe 2 links to each other with industrial computer 5 by flue gas analyzer 4, and on water-cooling wall wall 1, also be provided with the pyrometer couple 3 that is used to measure the water-cooling wall wall surface temperature, pyrometer couple 3 is transferred to industrial computer 5 with the temperature of the water-cooling wall wall that records, industrial computer 5 receives primary air velocity in power plant's mis system oracle database 6 simultaneously, pulverized-coal concentration, the secondary wind speed service data, the output of industrial computer 5 also is connected with display 7.

Certain power plant's #3 stove is the EII-670-13.8-545KT type steam boiler that the former Soviet Union red kettleman author manufactory produces, single drum, Natural Circulation, balanced draft, dry ash extraction coal-powder boiler.Two-layer up and down at combustion chamber both walls absolute altitude 13.6m and 18.1m punishment, liquidate and arrange 16 burners, design primary air velocity 20m/s, design secondary wind speed 28m/s.Boiler is since putting into operation, and operational excellence is in recent years because the coal anxiety uses the coal variation greatly, substantial deviation design coal (S _Ar=0.42%) the coal-fired S of reality recent years, _ArIn 1.5%～2.5% scope, in the maintenance of certain unit 3C level, by water-cooling wall outer wall 12-21m absolute altitude scope is checked, find absolute altitude 13-20 rice scope in the several 20-50 root scopes in front wall south, high temperature corrosion phenomenon is in various degree arranged in the back wall 14-20m scope, the average corrosion thinning 0.5-0.8mm of tube wall is in the critical point that needs replacing, is badly in need of carrying out crash analysis and processing.

After water screen tube has been changed in maintenance, device of the present invention is applied to this factory, in the high temperature corrosion zone, punch on the connecting plate of monowall tube, flue gas and wall temperature measuring point are installed, in front wall seriously corroded zone, two-layer measuring point is installed at absolute altitude 15.5m, 17.5m place, and one deck measuring point is installed at back wall tertiary air platform 19.5m place.

Referring to Fig. 2, be in operation, the present invention extracts flue gas by gas sampling probe 2, it is inboard concordant with water screen tube 8 that gas sampling probe 2 gos deep into burner hearth, flue gas in the gas sampling probe 2 extraction burner hearths is through flue gas analyzer 4 assays, data in real time is passed to industrial computer 5, industrial computer 5 is accepted the real-time wall temperature data that pyrometer couple 3 records simultaneously, primary air velocity, secondary wind speed, pulverized-coal concentration read from power plant's mis system oracle database in real time, and industrial computer 5 utilizes improved Fuzzy AHP to handle according to the following steps according to the data of measuring:

1) set up every layer of measuring point hierarchy Model: with 15.5m place measuring point is example, and with operation factor B1, atmosphere field B2 is a rule layer, pulverized-coal concentration C1, water-cooling wall wall temperature C2, primary air velocity C3, secondary wind speed C4 are the factor layer under the rule layer operation factor B1 correspondence, wall O ₂Concentration C 5, CO concentration C 6, SO ₂Concentration C 7 is the factor layer under the B2 correspondence of rule layer atmosphere field, sets up the pairing high temperature corrosion hierarchy Model of this measuring point and sees Fig. 3;

2) be benchmark with unit respective design parameter, formulate the metering weighted list;

3) determine the Fuzzy consistent matrix of rule layer: $\left[\begin{array}{cc}0.5& 0.5\\ 0.5& 0.5\end{array}\right]$

4). establish the Fuzzy consistent matrix of factor layer, and carry out the crash consistency check;

According to monitoring result, see Table 1, establish the Fuzzy consistent matrix of rule layer and factor layer:

The operation factor: $\left[\begin{array}{cccc}0.5& 0.6& 0.5& 0.8\\ 0.4& 0.5& 0.4& 0.7\\ 0.5& 0.6& 0.5& 0.8\\ 0.2& 0.3& 0.2& 0.5\end{array}\right]$ The atmosphere field: $\left[\begin{array}{ccc}0.5& 0.1& 0.2\\ 0.9& 0.5& 0.6\\ 0.8& 0.4& 0.5\end{array}\right]$

5). by formula $w_i=\frac{1}{n}-\frac{1}{2a}+\frac{1}{\mathrm{na}}\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{r}_{\mathrm{ij}},$ $(a\≥\frac{n-1}{2}),$ Calculate actual weight vector w _i, the factor layer actual weight that the actual weight value of rule layer is corresponding with these standards layer multiplies each other, and obtains total ordering of final each factor, finds out the factor that high temperature corrosion is had the greatest impact.

Table 1

According to result of calculation, before operation is adjusted, CO and SO ₂Shared weight is bigger, and the water-cooling wall wall severe depletion of oxygen of front wall 15.5m place is in reducing atmosphere.The operations staff is owing to worry the coal dust plugging, keep primary air velocity in high value always, and the adjustment of secondary wind speed is carried out fully by rule of thumb, secondary wind speed is too small, cause once pneumatic amount flow rate excessive, cause the uncombusted breeze airflow to whitewash a wall, coal dust burns near the tube wall face, water-cooling wall wall anoxic, form reducing atmosphere, adjust by operation, suitably increase by two sorrowful wall side burner secondary air flows, reduce the pulverized-coal concentration of two sorrowful wall side burners, make front-back wall wall oxygen amount abundance, after the adjustment, can see O ₂The actual weight maximum has been broken away from the reducing atmosphere of wall, but has been noticed simultaneously, and sulfur content is higher in the raw coal, is a principal element source of causing the easy high temperature corrosion of water-cooling wall, but adjusts by operation, can effectively alleviate the generation of high temperature corrosion.Apparatus of the present invention are applied to this factory, and water-cooling wall is checked in blowing out after operation half a year, finds that only there is slight point corrosion in some tube walls, and to use sulphur coal relevant with power plant for this, and the high temperature corrosion degree obviously alleviates, and is respond well, and it is sure to obtain manufacturer.

Claims (2)

1. the device of an on-line monitoring boiler water-cooling wall high-temperature corrosion, it is characterized in that: along the furnace height direction, offer the hole that the 1-5 layer is connected with flue gas sampling pipe (2) between water-cooling wall wall (1) pipe on the connecting plate (9), flue gas sampling pipe (2) stretches into burner hearth by perforate and extracts flue gas, flue gas sampling pipe (2) links to each other with industrial computer (5) by flue gas analyzer (4), and on water-cooling wall wall (1), also be provided with the pyrometer couple (3) that is used to measure water-cooling wall wall (1) temperature, pyrometer couple (3) is transferred to industrial computer (5) with the wall temperature of the water-cooling wall wall (1) that records, industrial computer (5) receives primary air velocity in power plant's mis system oracle database (6) simultaneously, pulverized-coal concentration, the secondary wind speed service data, the output of industrial computer (5) also is connected with display (7).

2. the on-line monitoring method of on-line monitoring boiler water-cooling wall high-temperature corrosion device as claimed in claim 1 is characterized in that, based on improved Fuzzy AHP, its concrete steps are as follows:

1) determine with high temperature corrosion A to be destination layer, with operation factor B1, atmosphere field B2 is a rule layer, and pulverized-coal concentration C1, water-cooling wall wall temperature C2, primary air velocity C3, secondary wind speed C4 are the factor layer under the rule layer operation factor B1 correspondence, wall O ₂Concentration C 5, CO concentration C 6, SO ₂Concentration C 7 is the factor layer under the B2 correspondence of rule layer atmosphere field, sets up the pairing high temperature corrosion hierarchy Model of each layer measuring point;

2) be benchmark with unit respective design parameter, formulate the metering weighted list;

3) establish the rule layer Fuzzy consistent matrix: it is identical to the high temperature corrosion influence degree with atmosphere field B2 to look operation factor B1, and the rule layer Fuzzy consistent matrix is taken as: $\left[\begin{array}{cc}0.5& 0.5\\ 0.5& 0.5\end{array}\right];$

4) establish the Fuzzy consistent matrix of factor layer, and carry out the crash consistency check

According to the metering weight of measurement index, making the shared metering weight of i kind factor is x, and the shared metering weight of j kind factor is y, then by formula r _Ij=x-y+0.5 calculates the relative weighting factor of structure Fuzzy consistent matrix, structural factor layer Fuzzy consistent matrix, and carry out consistency check;

The consistency check principle is: any nominated bank of matrix and the corresponding difference of all the other each row are some constants; If do not satisfy consistency check, then by formula: $r_{\mathrm{ij}}=\frac{1}{n}\underset{k=1}{\overset{n}{\mathrm{\Σ}}}(r_{\mathrm{ik}}-r_{\mathrm{jk}}+0.5),1\≤i,j\≤n,$ N is a matrix dimension,

To r _IjRecomputate, re-construct Fuzzy consistent matrix;

5) by formula $w_i=\frac{1}{n}-\frac{1}{2a}+\frac{1}{\mathrm{na}}\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{r}_{\mathrm{ij}},$ $(a\≥\frac{n-1}{2}),$ Calculate actual weight vector w _i, the factor layer actual weight that the actual weight value of rule layer is corresponding with these standards layer multiplies each other, and obtains total ordering of final each factor, finds out the factor that high temperature corrosion is had the greatest impact, if final CO concentration, SO ₂Concentration or the ordering of water-cooling wall temperature are forward, and CO concentration, SO are described ₂Concentration and water-cooling wall temperature height, industrial computer will instruct this zone to strengthen secondary air flow and suitably reduce the coal dust input amount, to reduce CO concentration, SO ₂Concentration and water-cooling wall temperature reduce the adverse effect to high temperature corrosion.

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