Power plant boiler heating surface ash pollution intelligent monitoring and cleaning method and closed-loop control system

Abstract

The application discloses a method and a closed-loop control system for monitoring, supervising and cleaning the ash pollution of a heating surface of a power plant boiler. The method comprises the following steps: setting an inner wall temperature measuring device or a wall temperature measuring point on a water-cooled wall of a furnace, setting a furnace endoscopic monitoring device, setting a data collector, an exchange, an intelligent server, a DCS data interface card, providing a calculation and modeling method for various pollution factors of the heating surface of the boiler, an overall average pollution factor of the water-cooled wall of the furnace, a local area pollution factor and a single-side average pollution factor of the water-cooled wall, providing a method for establishing an ash cleaning economic model, an ash cleaning safety model, an ash cleaning comprehensive evaluation model and a closed-loop control model, and setting a monitoring, supervising and monitoring picture. According to the method, a model is established in the intelligent server or the DCS system, a data reading module, a data preprocessing module and an intelligent ash cleaning database are established, the monitoring, supervising and monitoring picture is set, a closed-loop control system is constructed, the pollution state of the overall, single-side and local area of the heating surface and the water-cooled wall of the boiler, the state of an ash cleaner and a monitoring device and related parameters are monitored, supervised and monitored, the economy, safety and closed-loop control of the ash cleaning optimization of the boiler are realized, and the ash cleaning technology of various ash cleaners is suitable.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power plant boiler combustion and information control, and particularly relates to a power plant boiler heating surface ash pollution intelligent monitoring and cleaning method and closed-loop control system. BACKGROUND

[0002] During the operation of a power plant boiler, ash deposition and slagging are relatively common. Ash deposition and slagging not only affect the heat exchange effect of the boiler and the operation efficiency of the boiler, but also cause high-temperature and low-temperature corrosion of the heating surface of the boiler, increase the probability of tube explosion of the heating surface of the boiler, reduce the service life of the boiler, and affect the safe operation of the boiler. Therefore, the power plant boiler is equipped with a large number of ash cleaners, such as steam ash cleaners, acoustic ash cleaners, and shock wave ash cleaners. The operation personnel clean the ash according to the operation experience at regular time or according to shifts, which causes problems such as excessive blowing or insufficient blowing of the heating surface. In recent years, with the development of information technology, intelligent ash cleaning has been applied to power plant boilers, that is, the ash is cleaned according to the optimized calculation of the ash pollution of different heating surfaces of the boiler, and the ash is cleaned in a targeted manner. The ash of the heavily polluted heating surface is cleaned more frequently, and the ash of the lightly polluted heating surface is cleaned less frequently or not cleaned. However, the current intelligent ash cleaning patent technology has the following problems. First, the monitoring and pollution judgment of the boiler water wall and its local part are relatively insufficient, and the pollution monitoring model of the heating surface of the boiler is not reasonable. Second, the cleaning method does not give overall consideration to the safety and efficiency of the boiler, and the closed-loop control system is not reasonable. Third, the so-called intelligent ash cleaning closed-loop control system and method has an incorrect calculation model and poor practicability, which is not conducive to popularization. Fourth, the application scope is relatively narrow, and the method is only suitable for steam ash cleaning optimization of the boiler and is not suitable for acoustic and shock wave ash cleaning of the tail heating surface of the boiler. SUMMARY

[0003] Technical problem: The present application provides a power plant boiler heating surface ash pollution intelligent monitoring and cleaning method and closed-loop control system. The heating surface and water wall of the boiler are monitored and judged for pollution, the pollution monitoring model and the cleaning method of the heating surface of the boiler are optimized, and the safety and efficiency of the boiler are overall considered and automatically controlled in a closed loop.

[0004] Technical solution: The application provides a kind of power station boiler heating surface dust intelligent monitoring and cleaning method and closed-loop control system. By setting inner wall temperature measuring device or wall temperature measuring point on furnace water cooling wall, setting furnace endoscopic monitoring device, setting data collector, switch, intelligent server, DCS data interface card, providing various types of boiler heating surface pollution factor, furnace water cooling wall overall average pollution factor, local area pollution factor and single-side water cooling wall average pollution factor calculation and modeling method, providing cleaning economic model, cleaning safety model, cleaning comprehensive evaluation model and closed-loop control model establishment method, and setting monitoring and control picture method, according to the provided method, model is established in intelligent server or DCS system, and data reading module, data preprocessing module, intelligent cleaning database are established, monitoring and control picture is set, closed-loop control system is constructed, boiler heating surface and water cooling wall overall, single-side and local pollution state, cleaning device and monitoring equipment state and related parameters are monitored, monitored and controlled, the economy, safety and closed-loop control of boiler cleaning optimization are realized. The application is suitable for various cleaning technologies.

[0005] According to one aspect of the application, a kind of power station boiler heating surface dust intelligent monitoring and cleaning method is provided, comprising:

[0006] The method for setting inner wall temperature measuring device or wall temperature measuring point on furnace water cooling wall, setting furnace endoscopic monitoring device is provided, the local area pollution factor based on water cooling wall temperature monitoring and inner wall pollution monitoring is provided, the calculation and pollution judgment method of single-side water cooling wall average pollution factor and furnace water cooling wall overall average pollution factor is provided, and the overall, single-side and local pollution state of water cooling wall is monitored;According to the arrangement position and heat transfer state of boiler heating surface, different heating surfaces are divided into convection heating surface, half-radiation half-convection heating surface and full-radiation heating surface, and the same kind of different kinds of heating surfaces and the same kind of different sides of heating surfaces are calculated and modeled according to actual heat exchange and pollution condition and need respectively or as a whole, so as to provide the pollution monitoring method of boiler heating surface based on accurate classification, division and need;The establishment method of cleaning economic model, cleaning safety model, cleaning comprehensive evaluation model and closed-loop control model is provided, and the monitoring and control picture and its main information and control method are provided, to constitute the optimization cleaning comprehensive determination and monitoring and control method of boiler heating surface, furnace water cooling wall overall, single-side and local area.

[0007] The parameters represented by the letters with "qj" subscript or superscript in the application are the parameters of the boiler in the clean and ideal state, and the parameters represented by the letters with "sj" subscript or superscript are the parameters of the boiler in the actual running state.

[0008] In one embodiment, a plurality of inner wall temperature measuring devices and a plurality of in-furnace monitoring devices are arranged on the water-cooled wall fins between the wall-type soot blower or short soot blower area, and a model of the overall average pollution factor of the water-cooled wall of the furnace, a local area pollution factor and a single-side water-cooled wall average pollution factor are established to monitor the pollution state; each set of inner wall temperature measuring device is fixed on the water-cooled wall fin by a fixing member or directly welded, or is fixed on a support by a fixing nut and a gasket, the support is fixed on the water-cooled wall fin, the hot end of the inner wall temperature measuring device extends into the inner wall of the fin through the opening on the water-cooled wall fin, is flush with the inner wall or slightly extends out of the inner wall of the water-cooled wall fin and is fixed on the inner wall of the fin, is arranged between the wall-type soot blower or short soot blower, and a plurality of sets of inner wall temperature measuring devices are arranged in a grid shape on the four water-cooled walls, the number is determined according to the number of wall-type soot blowers or short soot blowers and the area of the water-cooled wall, the inner wall temperature measuring device is made of wear-resistant and high-temperature-resistant material, can measure the temperature range of 0-1300℃ or 0-1600℃, and can use high-temperature-resistant and wear-resistant K-graduated thermocouples, platinum-rhodium 40-platinum thermocouples or high-temperature thermometers; each in-furnace monitoring device is arranged on the in-furnace device support near the corner of the furnace, the in-furnace device support is fixed on the water-cooled wall fin, has a telescopic guide rail to ensure that the lens of the in-furnace device extends into and exits the water-cooled wall of the furnace, and ensures that the in-furnace monitoring device is arranged at a certain angle with the water-cooled wall at all times, the lens of the in-furnace device faces the inner side of the adjacent water-cooled wall and has cooling and self-cleaning functions, the lens of the in-furnace device has a wide-area panoramic monitoring function and wear-resistant and high-temperature-resistant performance, and the in-furnace monitoring device is used to monitor the ash and slag accumulation condition of the inner side of the adjacent water-cooled wall, the number is determined according to the size of the water-cooled wall area of the wall-type soot blower or short soot blower area; when the furnace width is large, 8 in-furnace monitoring devices are arranged in the same horizontal plane, are arranged in an axisymmetric manner, and 2 in-furnace monitoring devices are arranged on each side of the water-cooled wall, the distance from the intersection point of the monitoring center extension line of each set of in-furnace monitoring device and the water-cooled wall to the water-cooled wall where the device is located accounts for about 1 / 4 of the furnace width L; when the furnace width is small, 4 in-furnace monitoring devices are arranged in the same horizontal plane, are arranged in a central symmetric manner, and 1 in-furnace monitoring device is arranged on each side of the water-cooled wall; for a four-corner tangential firing boiler, the in-furnace monitoring devices are arranged in the tangential direction, the distance from the intersection point of the monitoring center extension line of each set of device and the water-cooled wall to the water-cooled wall where the device is located accounts for about 1 / 2 of the furnace width L; when the height of the water-cooled wall of the wall-type soot blower or short soot blower area is large, two layers are arranged, and when the height is small, one layer is arranged; the installation principle of the in-furnace monitoring device is: first, it is conducive to full-area monitoring; second, it is conducive to reducing the influence of flue gas and ash on the monitoring line of sight; and third, it is possible to utilize existing holes and reduce the water-cooled wall pipe drawing.

[0009] Based on the real-time measurement data of the inner wall temperature measuring device, the local area pollution factor of the water-cooled wall of the furnace is established as follows:

[0010]

[0011] wherein,

[0012] n is different sides of the furnace water wall, which can be represented by 1, 2, 3, 4 respectively for the left, right, front and back four sides of the furnace water wall, j is a local area of the water wall or a water wall area corresponding to the ash cleaner on different sides, Q Fsj , Q Fqj are the heat absorbed by the inner wall temperature measuring device corresponding to the water wall area in the actual state and in the cleaning state respectively, T rsj , T rqj are the temperatures of the inner wall temperature measuring device corresponding to the water wall area in the actual state and in the cleaning state respectively, σ0 is the Boltzmann constant, a sj , a qj are the furnace blackness of the inner wall temperature measuring device corresponding to the water wall area in the actual state and in the cleaning state respectively, s is the area of the inner wall temperature measuring device corresponding to the water wall area, C F is a dimensionless quantity, the larger the value, the more serious the pollution of the corresponding water wall area, and the pollution factor of different local areas of the water wall can be used as the pollution factor of the water wall area corresponding to the ash cleaner.

[0013] In one embodiment, wall temperature measuring points can also be provided on the water wall tube and the water wall fin to monitor the local temperature of the water wall, and a local area pollution factor model of the water wall is established to determine the local pollution state of the water wall; the wall temperature measuring point is composed of a wall temperature measuring point support, a tube wall temperature measuring point, a fin wall temperature measuring point, a fixed nut, a gasket or a thread, the tube wall temperature measuring point and the fin wall temperature measuring point are fixed on the wall temperature measuring point support through the fixed nut, the gasket or directly through the thread, the wall temperature measuring point support is fixed on the fin, the number of wall temperature measuring points is set according to the need for monitoring the pollution of the water wall in the area where the wall type ash cleaner or the short ash cleaner is located, and is arranged in a grid shape, for the membrane type water wall, the distance L between the tube wall temperature measuring point and the fin wall temperature measuring point in the wall temperature measuring point is S1 / 2±3, wherein S1 is the transverse pitch of the water wall tube.

[0014] Based on the real-time measured temperature of the tube wall temperature measuring point and the fin wall temperature measuring point in the wall temperature measuring point, heat flow coupling is carried out, and a local area pollution factor of the furnace water wall is established, which is:

[0015] C Fnj =1-Q fsj / Q fqj ,

[0016] wherein, Q fsj =λ sj (T 2sj -T 1sj ), Q fqj =λ qj (T 2qjT 1qj )

[0017] n is the different side of the furnace water wall, j is the local area of the water wall or the water wall area corresponding to the soot blower on the different side, Q fsj , Q fqj are the heat flow monitored in real time and the heat flow measured under the cleaning state respectively, λ sj , λ qj are the actual heat flow coefficient of the local area of the water wall or the water wall area corresponding to the soot blower and the heat flow coefficient under the cleaning state, T 2sj T 2qj are the actual temperature of the fin wall temperature measuring point and the temperature under the cleaning state of the wall temperature measuring point of the local area of the water wall or the water wall area corresponding to the soot blower, T 1sj , T 1qj are the actual temperature of the tube wall temperature measuring point and the temperature under the cleaning state of the wall temperature measuring point of the local area of the water wall or the water wall area corresponding to the soot blower, C f is dimensionless.

[0018] Based on the pollution factor of the local area of the water wall or the local area of the water wall corresponding to the soot blower, the average pollution factor of the single-sided water wall is obtained, which is:

[0019]

[0020] Wherein, C Fnk is the pollution factor of the local area of the furnace water wall, m is the number of the monitored local area of the furnace water wall, n is the different side of the furnace water wall, when n is 1, 2, 3, 4, it can represent the left, right, front and rear four sides of the furnace water wall respectively, j is the local area of the water wall or the water wall area corresponding to the soot blower on the different side.

[0021] The overall average pollution monitoring model of the furnace water wall heating surface is set, and the overall average pollution factor of the furnace water wall is:

[0022]

[0023] Wherein,

[0024]

[0025] x is the water wall angle coefficient, for the membrane type water wall, x = 1; ζ is the water wall fouling coefficient, T a is the theoretical combustion temperature, is the average thermal effective coefficient of the furnace, M is a parameter considering the relative position of the highest temperature of the flame in the furnace, which represents a constant of the flame center position, σ0 is the Boltzmann constant, a l is the furnace blackness, which is a hypothetical blackness representing the effective radiation of the flame; F lt is the furnace area, B is the furnace heat retention coefficient j B is the fuel quantity for the boiler, B is the average heat capacity of the combustion products, B is the flue gas temperature at the furnace outlet, which is obtained by back-calculation or direct monitoring of the flue gas temperature at the outlet of the economizer or other heating surface;

[0026] The overall average pollution factor of the water-cooled wall can also be calculated based on the average pollution factor of the single-side water-cooled wall, and is:

[0027]

[0028] wherein, B is the average pollution factor of the single-side water-cooled wall, and n is the number of different sides of the water-cooled wall of the furnace, which is 4 when the water-cooled wall of the furnace has four sides, and is 6 or 8 when the water-cooled wall of the furnace has six or eight sides;

[0029] In one embodiment, the pollution factor values of the local regions of the water-cooled wall, the overall average pollution factor of the water-cooled wall, and the average pollution factor of the single-side water-cooled wall are integrated, coupled with the main operating parameters of the boiler, and the regions where the water-cooled wall wall-type soot blower or short soot blower is located are monitored and judged and verified for local pollution by the furnace endoscopic monitoring device, to form a method for monitoring and optimizing pollution of the overall water-cooled wall of the furnace, the single-side water-cooled wall, and the local regions corresponding to the soot blower. During soot blowing, the relationship between pollution and soot blowing and ash accumulation time of the overall water-cooled wall, the single-side water-cooled wall, and the local regions determined in the soot blowing test is combined with the set soot blowing time limit, and the water-cooled wall, the single-side water-cooled wall, and the local regions are comprehensively judged for soot blowing in combination with a soot blowing economic model, a soot blowing safety model, and a soot blowing comprehensive evaluation.

[0030] According to the arrangement position and heat transfer condition of the boiler heating surface, the boiler heating surface is classified, and different heating surface pollution factor calculation methods are provided. The same kind and different kind of heating surface and the same kind and different side of the heating surface in the boiler are calculated and modeled respectively or as a whole according to the needs and the arrangement and heating condition of the boiler. The heating surface mainly by convection heat transfer is taken as the convection heating surface, such as the first re-heater, economizer, transition zone, evaporation heating surface, air preheater of the tower type boiler, and the last stage superheater, the last stage re-heater, the first stage superheater, the first stage re-heater, the economizer, the transition zone, the evaporation heating surface, and the air preheater of the ∏ type boiler. The heating surface with radiation heat transfer and convection heat transfer in the same order of magnitude is taken as the semi-radiation and semi-convection heating surface, such as the second re-heater, the second superheater of the tower type boiler, and the partition screen superheater or large screen superheater, the rear screen superheater or rear screen re-heater of the ∏ type boiler. The heating surface mainly by radiation heat transfer is taken as the full-radiation heating surface, such as the third stage superheater, the first stage superheater of the tower type boiler, and the front screen superheater, the wall type re-heater, and the boiler heating surface within the furnace outlet window of the ∏ type boiler.

[0031] Based on the classification of the boiler heating surface and the needs, the pollution factor of the boiler heating surface is calculated and modeled, such as the left side and the right side of the high temperature re-heater of the tower type boiler or the left side and the right side of the low temperature re-heater, which are calculated and modeled respectively according to the left side and the right side of the heating surface, so as to avoid the partial burning and realize the accurate control. The left side and the right side can also be combined as a whole to calculate the pollution factor and establish the model, so as to realize the overall control. The low temperature superheater and the low temperature re-heater which are both convection heating surfaces in the ∏ type boiler can be taken as a whole to calculate the pollution factor and establish the model. The whole or part of the boiler water wall can be taken as a full-radiation heating surface, and the pollution monitoring model can be established respectively.

[0032] No matter whether the solid fuel is used, the tube bundle is arranged in staggered arrangement, or the solid fuel is used, the tube bundle is arranged in in-line arrangement, or the gas fuel and the heavy oil are used (no matter whether the staggered arrangement or the in-line arrangement), the pollution factor of the convection heating surface is:

[0033] One calculation method is,

[0034]

[0035] Wherein, α1=ζ(α d +α f ),

[0036] D is the steam-water flow through the heating surface, Δh is the steam-water enthalpy rise between the outlet and inlet of the heating surface, α1 is the heat release coefficient of the flue gas side non-ash flow washing the clean tube wall, α2 is the heat release coefficient of the steam to the metal surface in the tube, A is the heat exchange area of the heating surface, Δt is the heat transfer temperature difference, ζ is the correction coefficient related to the uniformity of the flue gas washing the heating surface; α d is the heat release coefficient of the flue gas to the heating surface tube wall surface convection, f is the heat release coefficient of the flue gas to the heating surface tube wall radiation,

[0037] A calculation method is,

[0038]

[0039] Wherein, α1 = ζ (α d + α f ),

[0040] φ is the boiler heat retention coefficient of the corresponding section of the heating surface, ΔH is the flue gas enthalpy drop between the inlet and outlet of the flue gas side of the heating surface, B j is the calculated fuel quantity of the boiler, α1 is the heat release coefficient of the flue gas side non-ash flow washing the clean tube wall, α2 is the heat release coefficient of the steam to the metal surface in the tube, ζ is the correction coefficient related to the uniformity of the flue gas washing the heating surface; α d is the heat release coefficient of the flue gas to the heating surface tube wall surface convection, α f is the heat release coefficient of the flue gas to the heating surface tube wall radiation, A is the heat exchange area of the heating surface, Δt is the heat transfer temperature difference;

[0041] A calculation method is,

[0042]

[0043] Wherein,

[0044] α1 = ζ (α d + α f ),

[0045] K sj is the actual heat transfer coefficient of the heating surface, K qj is the clean heat transfer coefficient of the heating surface, B j is the calculated fuel quantity of the boiler, α1 is the heat release coefficient of the flue gas side non-ash flow washing the clean tube wall, α2 is the heat release coefficient of the steam to the metal surface in the tube, A is the heat exchange area of the heating surface, Δt is the heat transfer temperature difference, Q sj is the heat absorbed by the steam, D is the steam-water flow through the heating surface, Δh is the steam-water enthalpy rise between the outlet and inlet of the heating surface, ζ is the correction coefficient related to the uniformity of the flue gas washing the heating surface; α d is the heat release coefficient of the flue gas to the heating surface tube wall surface convection, αf Radiation heat release coefficient of flue gas to tube wall of heating surface;

[0046] When solid fuel is used and the tube bundle is arranged in staggered pattern, a calculation method for the pollution factor of the convection heating surface is,

[0047]

[0048] wherein,

[0049] α1= ζ (α d + α f ),

[0050] K sj is the actual heat transfer coefficient of the heating surface, B j is the calculated fuel quantity of the boiler, α1is the heat release coefficient of the clean tube wall washed by the flue gas without ash, α2is the heat release coefficient of the metal surface in the tube washed by the steam and water, A is the heat transfer area of the heating surface, Δt is the temperature and pressure difference of heat transfer, Q sj is the heat absorbed by the steam and water, D is the flow of the steam and water through the heating surface, Δh is the enthalpy rise of the steam and water between the outlet and the inlet of the heating surface, ε is the thermal resistance caused by the ash in the flue gas and the ash layer on the tube wall, ζ is the correction coefficient related to the uniformity of the flue gas washing the heating surface; α d is the convective heat release coefficient of the flue gas to the surface of the tube wall of the heating surface, α f Radiation heat release coefficient of flue gas to tube wall of heating surface; when solid fuel is used and the tube bundle is arranged in straight pattern, and when gas fuel and heavy oil (whether in staggered or straight pattern) are used, a calculation method for the pollution factor of the convection heating surface is,

[0051]

[0052] wherein, α1= ζ (α d + α f ),

[0053] K sj is the actual heat transfer coefficient of the heating surface, B j is the calculated fuel quantity of the boiler, α1is the heat release coefficient of the clean tube wall washed by the flue gas without ash, α2is the heat release coefficient of the metal surface in the tube washed by the steam and water, A is the heat transfer area of the heating surface, Δt is the temperature and pressure difference of heat transfer, Q sj is the heat absorbed by the steam and water, ψ is the thermal effective coefficient, which is the coefficient related to the actual heat transfer coefficient of the heating surface and the clean heat transfer coefficient; ζ is the correction coefficient related to the uniformity of the flue gas washing the heating surface; α d is the convective heat release coefficient of the flue gas to the surface of the tube wall of the heating surface, α f Radiation heat release coefficient of flue gas to tube wall of heating surface.

[0054] When solid fuel is used, the tube bundle is arranged in a staggered manner, and when solid fuel is used, the tube bundle is arranged in a straight line, and gas fuel and heavy oil are used (whether staggered or straight), the pollution factor of the economizer, the transition zone of the once-through boiler, the evaporation heating surface, and the heating surface of the supercritical pressure boiler as the convection heating surface is:

[0055] A calculation method is,

[0056]

[0057] D is the steam and water flow through the heating surface, Δh is the steam and water enthalpy rise between the outlet and the inlet of the heating surface, A is the heat exchange area of the heating surface, Δt is the heat transfer temperature difference, α1 is the heat release coefficient of the clean tube wall flushing by the flue gas side ash-free gas flow, ζ is the correction coefficient related to the uniformity of the flue gas flushing the heating surface, α d is the convective heat release coefficient of the flue gas to the heating surface tube wall surface, α f is the radiative heat release coefficient of the flue gas to the heating surface tube wall;

[0058] A calculation method is,

[0059]

[0060] Wherein, α1 = ζ (α d + α f ),

[0061] φ is the boiler heat retention coefficient corresponding to the area of the heating surface, ΔH is the flue gas enthalpy drop between the inlet and the outlet of the heating surface, B j is the calculated fuel quantity of the boiler, A is the heat exchange area of the heating surface, Δt is the heat transfer temperature difference, α1 is the heat release coefficient of the clean tube wall flushing by the flue gas side ash-free gas flow, α1 is the heat release coefficient of the clean tube wall flushing by the flue gas side ash-free gas flow, ζ is the correction coefficient related to the uniformity of the flue gas flushing the heating surface; α d is the convective heat release coefficient of the flue gas to the heating surface tube wall surface, α f is the radiative heat release coefficient of the flue gas to the heating surface tube wall;

[0062] When solid fuel is used, the tube bundle is arranged in a staggered manner, and when solid fuel is used, the tube bundle is arranged in a straight line, and gas fuel and heavy oil are used (whether staggered or straight), the pollution factor of the economizer, the transition zone of the once-through boiler, the evaporation heating surface, and the heating surface of the supercritical pressure boiler as the convection heating surface is defined,

[0063]

[0064] Wherein, α1 = ζ (α d + α f ),

[0065] K sjis the actual heat transfer coefficient of the heating surface, ε is the thermal resistance caused by the ash in the flue gas and the ash layer on the tube wall, B j Calculate the fuel quantity for the boiler, A is the heat transfer area of ​​the heating surface, Δt is the heat transfer temperature and pressure of the heating surface, Q sj is the heat absorbed by steam and water, α1 is the heat release coefficient of the ash-free airflow on the clean pipe wall on the flue gas side, α2 is the heat release coefficient of steam and water on the metal surface inside the pipe, and ζ is the correction coefficient related to the uniformity of the flue gas scouring the heating surface; d is the convection heat release coefficient of flue gas to the heating surface of the tube wall, α f The radiation heat release coefficient of flue gas to the heating surface tube wall;

[0066] When burning solid fuels, the tube bundles are arranged in series, and when burning gas fuels and heavy oil (whether staggered or in series), the economizer, the transition zone of the once-through boiler, the evaporation heating surface, and the heating surface of the supercritical pressure boiler are used as convection heating surfaces, the pollution factor can be calculated as follows:

[0067]

[0068] in,

[0069] α1=ζ(α d +α f ),

[0070] ψ is the thermal effectiveness coefficient, which represents the coefficient related to the actual heat transfer coefficient and clean heat transfer coefficient of the heated surface; K sj is the actual heat transfer coefficient of the heating surface, α1 is the heat release coefficient of the ash-free airflow on the flue gas side to scour the clean pipe wall, Q sj is the heat absorbed by the soda, B j Calculate the fuel quantity for the boiler, A is the heat exchange area of ​​the heating surface, Δt is the heat transfer temperature and pressure of the heating surface, α2 is the heat release coefficient of steam and water to the metal surface inside the tube, ζ is the correction coefficient related to the uniformity of flue gas washing the heating surface; α d is the convection heat release coefficient of flue gas to the heating surface of the tube wall, α f The radiation heat release coefficient of flue gas to the heated surface tube wall.

[0071] Pollution factor of semi-radiative and semi-convective heating surface:

[0072] One calculation method is,

[0073]

[0074] in,

[0075]

[0076] K sjK is the actual heat transfer coefficient of the heating surface qj Q is the heat transfer coefficient of the heating surface corresponding to the clean state sj B is the actual heat absorbed by the steam and water of the heating surface j H is the heat transfer area of the heating surface, and Δt is the actual heat transfer temperature difference of the heating surface fqj Q is the radiation heat absorbed by the heating surface corresponding to the clean state dqj D is the steam and water flow rate of the heating surface corresponding to the clean state, i" and i' are the outlet enthalpy and inlet enthalpy of the steam and water of the heating surface corresponding to the clean state, and α1 and α2 are the heat release coefficients of the clean tube wall and the metal surface inside the tube, respectively

[0077] A calculation method is

[0078]

[0079] wherein D is the steam and water flow rate passing through the heating surface, Δh sj B is the actual enthalpy rise of the steam and water between the outlet and the inlet of the heating surface, H is the heat transfer area of the heating surface, and ΔT sj B is the actual temperature difference of the heating surface j H is the heat transfer area of the heating surface, and Δh qj Q is the enthalpy rise of the heating surface corresponding to the clean state fqj Q is the radiation heat absorbed by the heating surface corresponding to the clean state, and α1 and α2 are the heat release coefficients of the clean tube wall and the metal surface inside the tube, respectively

[0080] A calculation method is

[0081]

[0082] wherein, B is the heat retention coefficient, and ΔH sj Q is the actual enthalpy drop of the flue gas between the inlet and the outlet of the heating surface fsj B is the actual radiation heat absorbed by the heating surface, H is the heat transfer area of the heating surface, and ΔT sj B is the actual heat transfer temperature difference of the heating surface, α1 and α2 are the heat release coefficients of the clean tube wall and the metal surface inside the tube, respectively, and Q fqj Q is the radiation heat absorbed by the heating surface corresponding to the clean state, and ΔH qj Q is the enthalpy drop of the flue gas between the inlet and the outlet of the heating surface under the clean state

[0083] A calculation method is

[0084]

[0085] wherein,

[0086]

[0087] K sj is the actual heat transfer coefficient of the heating surface, ε is the ash fouling coefficient caused by the ash in the flue gas and the thermal resistance caused by the ash fouling layer of the heating surface; Q fsj is the actual radiation heat absorption of the heating surface, Q dsj is the actual absorption of the flue gas convection heat release of the heating surface, Q sj is the actual absorption of the heating surface steam water heat, H is the heat transfer area of the heating surface, ΔT sj is the actual temperature and pressure of the heating surface, α1 is the heat release coefficient of the ash-free gas flow on the flue gas side to the clean tube wall, and α2 is the heat release coefficient of the steam to the metal surface in the tube;

[0088] A calculation method is,

[0089]

[0090] wherein, B j is the calculated fuel quantity of the boiler, Q fsj is the actual radiation heat absorption of the heating surface, D is the steam water flow through the heating surface, Δh is the steam enthalpy rise between the outlet and the inlet of the heating surface, H is the heat transfer area of the heating surface, ΔT is the actual temperature and pressure of the heating surface, α1 is the heat release coefficient of the ash-free gas flow on the flue gas side to the clean tube wall, and α2 is the heat release coefficient of the steam to the metal surface in the tube;

[0091] A calculation method is,

[0092]

[0093] wherein, φ is the boiler heat retention coefficient of the section where the heating surface is located, ΔH is the actual enthalpy drop of the flue gas between the inlet and the outlet of the heating surface, Q fsj is the actual radiation heat absorption of the heating surface, H is the heat transfer area of the heating surface, ΔT is the heat transfer temperature and pressure of the heating surface, α1 is the heat release coefficient of the ash-free gas flow on the flue gas side to the clean tube wall, and α2 is the heat release coefficient of the steam to the metal surface in the tube;

[0094] For the pollution factor calculation formula of the semi-radiation semi-convection heating surface, α1:

[0095] When the semi-radiation semi-convection heating surface is a screen heating surface or a tube heating surface, α1 is,

[0096]

[0097] wherein, α d is the flue gas side convection heat release coefficient calculated according to the outer surface area of the heating surface tube, s pzis the longitudinal pitch of the screen or tube heating surface, x p is the angular coefficient of the screen or tube heating surface, d is the outer diameter of the heating surface tube, α f is the radiation heat release coefficient of the flue gas to the tube wall, ζ is the utilization coefficient, which is the coefficient that reduces the heat due to incomplete flushing of the screen;

[0098] When the semi-radiation and semi-convection heating surface is a tubular heating surface, α1 can also be calculated according to the following formula:

[0099] α1=ζ(α d +α f ),

[0100] Among them, α1 is the heat release coefficient of the ash-free airflow on the flue gas side scouring the unclean pipe wall, α d is the convection heat release coefficient of flue gas to the tube wall surface, α f is the radiation heat release coefficient of flue gas to the pipe wall.

[0101] In the pollution factor calculation formula for semi-radiation and semi-convective heating surfaces, the calculation method for radiation heat absorption is as follows:

[0102] (1) The radiation heat absorption Q absorbed by the first semi-radiation and semi-convective heating surface in the corresponding clean state fqj for,

[0103]

[0104] in,

[0105]

[0106] Q′ flqj Q″ is the radiation heat absorbed by the inlet cross-sectional area of ​​the first semi-radiation heating surface near the furnace outlet in a clean state. f1qj is the heat radiated from the furnace and the first semi-radiant heating surface and the flue gas in between to the second heating surface behind the flue gas process in a clean state, η g is the coefficient of uneven heat load at the furnace outlet window; β is the correction coefficient considering the mutual radiation effect between the furnace and the first semi-radiation heating surface; q H is the average heat load of the furnace radiation heating surface, The effective radiation heating surface of the furnace absorbs heat for 1 kg of fuel, A lf is the total effective radiation heating area of ​​the furnace, B j Calculate the fuel quantity for the boiler, F l ″ is the cross-sectional area of ​​the furnace outlet smoke window, a1 is the smoke blackness between the first semi-radiation heating surfaces; x gr1 F is the angular coefficient of the inlet section to the outlet section of the first semi-radiant heating surface; gr1 is the flue gas outlet area of ​​the first semi-radiant heating surface, Tgr1 is the average temperature of the flue gas between the first semi-radiation heating surfaces, ξ r To take into account the correction factor of fuel type, for coal ξ r =0.5;

[0107] The actual radiation heat Q of the first semi-radiation and semi-convection heating surface at the furnace outlet fsj The radiation heat Q absorbed in the corresponding clean state fqj The calculation method is the same as that of , and the calculation is performed according to the parameters in the actual state;

[0108] (2) For the second heating surface behind the flue gas flow of the first semi-radiant heating surface at the furnace outlet, the radiation heat Q absorbed in the clean state f2qj for,

[0109]

[0110] in,

[0111] Q f1qj Q″ is the heat radiated from the furnace and the first semi-radiant heating surface to the second heating surface behind the flue gas process in a clean state. f2qj is the heat radiated from the second semi-radiant heating surface and its flue gas in a clean state to the third heating surface behind the flue gas flow; β2 is the correction coefficient considering the mutual radiation effect between the first semi-radiant heating surface and the second heating surface behind the flue gas flow; a2 is the smoke blackness between the second heating surface; x gr2 F″ is the angular coefficient of the inlet section to the outlet section of the second heating surface; gr2 is the flue gas outlet area of ​​the second heating surface, T gr2 is the average temperature of the flue gas between the second heating surfaces, ξ r2 To consider the correction factor of fuel type, B j Calculate fuel quantity for boiler.

[0112] For the second heating surface behind the flue gas flow of the first semi-radiant heating surface at the furnace outlet, the actual absorbed radiation heat Q f2sj Calculation method and the absorbed radiation heat Q in clean state f2qj The calculation method is the same as that of , and the calculation is performed according to the parameters in the actual state.

[0113] The calculation formula for the pollution factor of the fully radiant heating surface is as follows:

[0114]

[0115] in,

[0116] D is the evaporative capacity of the total radiation heating surface, Δh is the enthalpy rise of steam between the outlet and inlet of the total radiation heating surface, A p The effective radiation area of the total radiation heating surface, ζ p The fouling absorption coefficient of the total radiation heating surface; η i is the radiation heat absorption distribution coefficient of the total radiation heating surface; The effective radiation heat intensity of the total radiation heating surface, q H is the average heat load of the total radiation heating surface of the furnace, is the heat absorbed by the effective radiation heating surface of the furnace per 1 kg of fuel, A lf is the total effective radiation heating area of the furnace, B j is the calculated fuel quantity of the boiler.

[0117] The pollution factor of the air preheater as a convection heating surface, whether it is a tubular air preheater or a rotary air preheater, one calculation method is,

[0118]

[0119] wherein,

[0120] respectively, the actual conversion differential pressure of the air preheater, the conversion differential pressure under clean conditions, O 2，xgy sj , O 2，0gy sj respectively, the oxygen content in the dry flue gas under actual conditions and actual conversion conditions, MW x sj , MW0 sj respectively, the generator power under actual conditions and actual conversion conditions, O 2，zgy qj , O 2，0gy qj respectively, the oxygen content in the dry flue gas under clean conditions and clean conversion conditions, the actual conversion condition is the condition under rated power and a certain dry flue gas oxygen content in the actual pollution state; MW x qj , MW0 qj respectively, the generator power under clean conditions and clean conversion conditions, the clean conversion condition is the condition under rated power and a certain dry flue gas oxygen content in the clean condition;

[0121] For a tubular air preheater, the pollution factor, one calculation method is,

[0122]

[0123] wherein,

[0124] Ksjk , K qjk are actual heat transfer coefficient and heat transfer coefficient under clean condition of air preheater respectively, Q d is heat absorbed by air of air preheater, A is heat transfer outer surface area of air preheater, Δt is temperature difference of air preheater heat transfer, α1, α2 are flue gas heat release coefficient and air heat release coefficient of air preheater respectively, B j is calculated fuel quantity of boiler;

[0125] For tubular air preheater, pollution factor, one calculation method is,

[0126]

[0127] Wherein,

[0128] K sjk is actual heat transfer coefficient of air preheater, α1, α2 are flue gas heat release coefficient and air heat release coefficient of air preheater respectively, ζ is utilization coefficient, which represents comprehensive influence coefficient of ash pollution and incomplete flushing of air preheater heating surface;

[0129] For rotary air preheater, pollution factor, one calculation method is,

[0130]

[0131] Wherein,

[0132] K sjk is actual heat transfer coefficient of air preheater, C is non-steady heat transfer influence coefficient caused by speed change; x y , x k are flue gas and air flushing rotor share respectively; α1, α2 are flue gas heat release coefficient and air heat release coefficient of air preheater respectively, ζ is utilization coefficient, which represents comprehensive influence coefficient of ash pollution and incomplete flushing of air preheater heating surface;

[0133] For rotary air preheater, pollution factor, one calculation method is,

[0134]

[0135] Wherein,

[0136]

[0137] K sjk , K qjk are actual and clean condition heat transfer coefficient of air preheater respectively, C is non-steady heat transfer influence coefficient caused by speed change; x y , x kThe share of flue gas and air flushing rotor respectively; α1, α2 are the flue gas heat release coefficient and air heat release coefficient of air preheater heating surface respectively;

[0138] Whether it is a tubular air preheater or a rotary air preheater, the actual heat transfer coefficient is,

[0139]

[0140] Wherein

[0141] β" ky The excess air coefficient of air preheater outlet air; Δα ky The air leakage coefficient of air preheater air leakage to flue gas; The theoretical air enthalpy value on the air preheater air outlet and inlet section respectively, B j The calculated fuel quantity of the boiler, Δt is the logarithmic mean temperature and pressure, Δt d The medium temperature difference of the end with larger temperature difference in the air preheater heating surface, Δt x The medium temperature difference of the end with smaller temperature difference in the air preheater heating surface, A is the heat transfer area of the air preheater.

[0142] As an aspect of the method for monitoring and cleaning the ash pollution of the heating surface of a power station boiler, the method for establishing the cleaning economic model is: combining the boiler steam cleaning field test, according to the quantitative influence data of the cleaning action on the main steam temperature, the reheat steam temperature and the exhaust gas temperature under different working conditions measured by the control variable method, representing the comprehensive influence on the boiler efficiency as the basis for system economic evaluation; at the same time, the cleaning consumption and cleaning benefit are comprehensively considered, including:

[0143] (1) According to the field experiment, the influence model of each group of ash cleaner action on the boiler efficiency under different loads is established, such as the action benefit of each group of ash cleaner is the heat transfer capacity increased after the cleaning of each group of ash cleaner, that is, the increase of the boiler efficiency and the benefit;

[0144] (2) According to the operating parameters, the operating consumption cost model of each group of ash cleaner is established, such as the operating consumption cost of each group of ash cleaner = steam consumption of each ash cleaner per cleaning x total input of each group of ash cleaner within a certain time x unit steam consumption and power consumption cost;

[0145] (3) The cleaning economic model of each group of ash cleaner is established to realize the economic optimization of cleaning operation, such as the comprehensive economic benefit = the benefit increase brought by the cleaning of each group of ash cleaner - operating consumption cost + steam consumption and power consumption cost saved by reducing the cleaning frequency + labor operation cost and equipment maintenance cost saved + safety benefit brought by reducing the blowout of the boiler heating surface + environmental protection benefit brought by reducing the waste gas emission, which is maximized under the premise of ensuring the safety of operating parameters;

[0146] As one aspect of the intelligent monitoring and monitoring and soot blowing method of the heating surface of a power plant boiler, the method for establishing a soot blowing safety model is:

[0147] 1) The daily soot blowing frequency of each soot blower cannot be higher than the set upper limit, such as no more than three times per day for each soot blower;

[0148] 2) The soot blowing frequency of each soot blower within a certain time cannot be lower than the lower limit, such as no less than five times per week for each soot blower;

[0149] 3) Ensuring that the main steam temperature and the reheat steam temperature are not over-temperature or under-temperature is an important condition for intelligent soot blowing, such as setting the main steam temperature to be no higher than 3℃ above the design temperature and no lower than 5℃ below the design temperature; setting the reheat steam temperature to be no higher than 3℃ above the design temperature and no lower than 4℃ below the design temperature;

[0150] 4) Setting a low load limit for which soot blowing is not performed, such as setting no soot blowing below 30% of the rated load or 25% of the rated load;

[0151] 5) Setting the soot blower action and state signal to enter the DCS, and immediately exiting the soot blower when the signal is not normal.

[0152] As one aspect of the intelligent monitoring and monitoring and soot blowing method of the heating surface of a power plant boiler, the method for establishing a soot blowing comprehensive evaluation model is: combining the soot blowing economic model and the soot blowing safety model to establish a soot blowing comprehensive evaluation model, obtaining the boiler operating parameters in real time, setting the non-soot blowing safety limit conditions, and timely suspending or stopping soot blowing; and evaluating the economy by comprehensively considering the soot blowing steam consumption, power consumption, soot blowing income, steam temperature, exhaust gas temperature, and frequency.

[0153] As an aspect of the method for intelligent monitoring and cleaning of the heating surface of a power plant boiler, the method for establishing the closed-loop control model comprises: establishing control logic in an intelligent server or a DCS system, and integrating the accurate monitoring data of the pollution state of the whole, single side and local area of the boiler heating surface and water wall, comprehensive evaluation information of cleaning and safety information into the control program; including: the whole, single side and local area of the furnace water wall, the convection heating surface, the full radiation, the semi-radiation and semi-convection heating surface and the air preheater, and according to the pollution factor model and the grouping of the cleaning device, and the safety, economic and comprehensive judgment of the cleaning is included in the control program; the established control program can realize the optimized control of the cleaning device according to the modeling grouping of the heating surface and the independent control of the single cleaning device, realize the separate control of the boiler heating surface, different sides, the whole, single side and local area of the water wall, realize the on-demand, economic and safe cleaning; at the same time, the control logic of the existing cleaning device is reserved, and the interlocking and switching conditions of the closed-loop control model and the existing cleaning device control logic and the intelligent cleaning start button are set to ensure the normal and safe switching and operation of the two cleaning methods;

[0154] As an aspect of the method for intelligent monitoring and cleaning of the heating surface of a power plant boiler, the method for establishing the closed-loop control model comprises: establishing control logic in an intelligent server or a DCS system, and integrating the accurate monitoring data of the pollution state of the whole, single side and local area of the boiler heating surface and water wall, comprehensive evaluation information of cleaning and safety information into the control program; including: the whole, single side and local area of the furnace water wall, the convection heating surface, the full radiation, the semi-radiation and semi-convection heating surface and the air preheater, and according to the pollution factor model and the grouping of the cleaning device, and the safety, economic and comprehensive judgment of the cleaning is included in the control program; the established control program can realize the optimized control of the cleaning device according to the modeling grouping of the heating surface and the independent control of the single cleaning device, realize the separate control of the boiler heating surface, different sides, the whole, single side and local area of the water wall, realize the on-demand, economic and safe cleaning; at the same time, the control logic of the existing cleaning device is reserved, and the interlocking and switching conditions of the closed-loop control model and the existing cleaning device control logic and the intelligent cleaning start button are set to ensure the normal and safe switching and operation of the two cleaning methods;

[0155] When the mouse is at the soot blower number, the left button is clicked to operate the soot blower, and the right button is clicked to display the state of the corresponding soot blower. When the mouse is at the drain valve button, the left button is clicked to operate the drain valve, and the right button is clicked to display the state of the drain valve. When the mouse is at the main steam valve button, the left button is clicked to operate the main steam valve, and the right button is clicked to display the state of the main steam valve. When the mouse is at the auxiliary steam valve, the left button is clicked to operate the auxiliary steam valve, and the right button is clicked to display the state of the auxiliary steam valve. When the mouse is at the in-furnace monitoring device number, the corresponding monitoring data is displayed. When the mouse is at the inner wall temperature measuring device or wall temperature measuring point number, the corresponding monitoring data is displayed. When the mouse is at the intelligent soot blowing start button, the left button is clicked to realize the intelligent soot blowing closed-loop control linkage and unlocking. When unlocked, the intelligent soot blowing control program is interrupted, and can be linked with the original soot blowing program to realize the interactive use of the intelligent soot blowing program and the original soot blowing program.

[0156] According to another aspect of the present application, there is provided an intelligent monitoring and cleaning closed-loop control system for the heating surface of a power plant boiler, comprising: inner wall temperature measuring devices or wall temperature measuring points, a furnace endoscopic monitoring device, a data collector, a compensation lead, a communication cable, a switch, an optical fiber or communication cable, an intelligent server, a DCS system, a DCS data interface card, and a communication protocol, wherein the inner wall temperature measuring devices or wall temperature measuring points are arranged on the furnace water wall, and the furnace endoscopic monitoring device is arranged, the inner wall temperature measuring devices or wall temperature measuring points are connected to the data collector through the compensation lead, a plurality of data collectors are connected in series through the communication cable and then connected to the switch, the data of the inner wall temperature measuring devices or wall temperature measuring points are sent to the switch through the data collector, the furnace endoscopic monitoring device is connected to the switch through the twisted pair or communication cable for communication and sending video data to the switch, the switch is connected to the DCS system through the optical fiber or communication cable for sending the new measuring point data to the DCS system, the data measured by the inner wall temperature measuring devices or wall temperature measuring points, the furnace endoscopic monitoring device, and the measuring points arranged in the heating surface area of the boiler as needed, the intelligent server is connected to the DCS system through the communication cable for data reading and writing in the OPC communication protocol mode, or connected to the DCS data interface card through the communication cable for data reading and writing in the modbus communication protocol, a software model is established in the intelligent server, including various pollution factor calculation models, a cleaning economic model, a cleaning safety model, a cleaning comprehensive evaluation model established according to the method provided in the present application, and a data reading module, a data preprocessing module, and an intelligent cleaning database, a closed-loop control model and a monitoring and control screen are arranged in the intelligent server or the DCS system; the intelligent server reads data from the DCS system through the data reading module, processes the data through the data preprocessing module, and then sends the data to the intelligent cleaning database, the cleaning safety model, and the cleaning economic model, the pollution factor calculation model obtains data from the intelligent cleaning database and sends the calculated pollution factor data to the closed-loop control model while returning to the intelligent cleaning database, the cleaning safety model and the cleaning economic model send the operation results to the cleaning comprehensive evaluation model for comprehensive evaluation and send the comprehensive evaluation information to the closed-loop control model, the closed-loop control model realizes the operation optimization control of the cleaning device after processing the pollution factor data and the comprehensive evaluation information, and the monitoring and control screen reads the pollution factor data from the intelligent cleaning database and obtains relevant parameters and equipment state information from the DCS system for monitoring and control.

[0157] The present application has the following positive and beneficial effects: the present application provides an intelligent monitoring and cleaning method and a closed-loop control system for the heating surface of a power plant boiler, which monitors and judges the pollution of the overall, single side, and local area of the boiler heating surface and water wall, optimizes the pollution monitoring model and cleaning method of the boiler heating surface, and realizes the overall consideration of safety and efficiency and automatic closed-loop control of the boiler. BRIEF DESCRIPTION OF THE DRAWINGS

[0158] In order to better illustrate the embodiments of the present invention or the technical solutions of the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the prior art. The following drawings are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative technical labor.

[0159] Figure 1 A schematic diagram of a system connection structure according to an embodiment of the present invention;

[0160] Figure 2 A schematic diagram of monitoring and surveillance according to an embodiment of the present invention;

[0161] Figure 3 An embodiment of the present invention Figure 1 A partial schematic diagram of the rotation in the direction A, showing the arrangement of the water-cooled wall tubes, water-cooled wall fins, wall-type dust collector, endoscope monitoring device, and inner wall temperature measuring device. The fixing method of the inner wall temperature measuring device is not fully shown in the figure;

[0162] Figure 4-1 、 Figure 4-2 for Figure 3 BB cross-sectional diagrams respectively represent different fixing methods of the inner wall temperature measuring device;

[0163] Figure 5-1 、 5-2 for Figure 3 The CC cross-sectional diagram in FIG. 1 shows two different arrangements of the number of furnace endoscopic monitoring devices when the furnace width is small and the furnace width is large;

[0164] Figure 6 Another embodiment of the invention Figure 1 The B-direction rotating partial schematic diagram shows the layout of water-cooled wall tubes, water-cooled wall fins, wall-type dust collectors, and measuring points;

[0165] Figure 7-1 、 7-2 for Figure 6 DD cross-sectional diagram, showing different fixing methods of measuring point;

[0166] Figure 8 This is a logic diagram for optimizing the dust cleaning economic model of the present invention;

[0167] Figure 9 It is a flow chart of the monitoring, surveillance and control system of the present invention. DETAILED DESCRIPTION

[0168] The following examples of the present application are provided to further illustrate the present patent and are not intended to limit the scope of the present application. Other examples of the present application, which are within the scope of the present application, will be apparent to those skilled in the art from the examples provided herein. Unless otherwise specified, the components and relative arrangements of the components, expressions, and data in these examples are not intended to limit the scope of the present application. The dimensions of the various parts in the drawings are not to scale and are intended for illustrative purposes only.

[0169] The techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail herein, but should be considered as if the discussion were incorporated herein by reference; any specific values are exemplary only and are not intended to limit the scope of the application. Similar reference characters denote like features throughout the several views of the drawings and like numbers designate like items in the examples.

[0170] The present application provides a method for intelligent monitoring and cleaning of the heating surface of a power plant boiler and a closed-loop control system. The present application provides a method for intelligent monitoring and cleaning of the heating surface of a power plant boiler and a closed-loop control system. By providing an inner wall temperature measuring device 9 or wall temperature measuring point 12 on the furnace water wall, a furnace endoscopic monitoring device 7, a data collector 11, a switch 1, an intelligent server 6, a DCS data interface card 4, and a method for calculating and modeling the pollution factors of various types of heating surfaces of the boiler, the overall average pollution factor of the furnace water wall, the local area pollution factor, and the average pollution factor of the single-sided water wall, a method for establishing a cleaning economic model, a cleaning safety model, a cleaning comprehensive evaluation model, and a closed-loop control model, and a method for setting up a monitoring and control screen, and based on the provided methods, establishing a model in the intelligent server or DCS system, and establishing a data reading module, a data preprocessing module, an intelligent cleaning database, setting up a monitoring and control screen, and constructing a closed-loop control system, the overall, single-sided, and local pollution state of the boiler heating surface and water wall, the state of the cleaning device and monitoring equipment, and related parameters are monitored and controlled, and the economy, safety, and closed-loop control of the boiler cleaning optimization are achieved.

[0171] According to one aspect of the present application, a method for intelligent monitoring and cleaning of the heating surface of a power plant boiler is provided, comprising:

[0172] The application provides a method for setting an inner wall temperature measuring device 9 or wall temperature measuring point 12 on a furnace water cooling wall, setting a furnace endoscopic monitoring device, providing a local area pollution factor based on water cooling wall temperature monitoring and inner wall pollution monitoring, providing calculation and pollution judgment methods for a single-side water cooling wall average pollution factor and a furnace water cooling wall overall average pollution factor, and monitoring the overall, single-side and local pollution state of the water cooling wall; according to the arrangement position and heat transfer state of the boiler heating surface, different heating surfaces are divided into convection heating surfaces, semi-radiation semi-convection heating surfaces and full-radiation heating surfaces, and the same kind of different types of heating surfaces and the same type of different sides of heating surfaces are calculated and modeled according to the actual heat exchange and pollution state and needs, respectively or as a whole, so as to provide a pollution monitoring method for the boiler heating surface based on accurate classification, combination and needs; the application provides a method for establishing a cleaning economic model, a cleaning safety model, a cleaning comprehensive evaluation model and a closed-loop control model, and provides a monitoring monitoring control screen and main information and a control method, thereby forming a comprehensive judgment and monitoring monitoring control method for the boiler heating surface, the overall, single-side and local area of the furnace water cooling wall, and the optimization of cleaning; the parameters represented by the letters with the subscript or superscript of "qj" in the embodiments of the application are parameters of the boiler in a clean ash-free or ideal state, and the parameters represented by the letters with the subscript or superscript of "sj" are parameters of the boiler in an actual running state.

[0173] As Figure 1 , Figure 3 , Figure 4-1 , Figure 4-2 , Figure 5-1 , Figure 5-2As shown, in one embodiment, a plurality of inner wall temperature measuring devices 9 and a plurality of in-furnace monitoring devices 7 are arranged on the water-cooled wall fins between the wall-type soot blower or short soot blower area, and the overall average pollution factor model of the furnace water-cooled wall, the local area pollution factor model and the single-side water-cooled wall average pollution factor model are established to monitor the pollution state; each set of inner wall temperature measuring device 9 is fixed on the water-cooled wall fin by fixing member 13 or directly welded, or fixed on the bracket 16 through fixing nut 14 and gasket 15, the bracket 16 is fixed on the water-cooled wall fin, the hot end of the inner wall temperature measuring device 9 extends into the inner wall of the fin through the opening on the water-cooled wall fin, and is flush with the inner wall or slightly extends out of the inner wall of the water-cooled wall fin and is fixed on the inner wall of the fin, arranged between the wall-type soot blower or short soot blower, a plurality of inner wall temperature measuring devices 9 are arranged in grid shape on the four water-cooled walls respectively, the number is determined according to the number of wall-type soot blower or short soot blower and the area of water-cooled wall, the inner wall temperature measuring device 9 is made of wear-resistant and high-temperature-resistant material, which can measure the temperature range of 0-1300℃ or 0-1600℃, the inner wall temperature measuring device 9 can use high-temperature-resistant and wear-resistant K-graduation thermocouple, platinum-rhodium 40-platinum thermocouple or high-temperature thermometer; each in-furnace monitoring device 7 is arranged on the in-furnace monitoring device bracket near the corner of the furnace, the in-furnace monitoring device bracket is fixed on the water-cooled wall fin, has telescopic guide rail to ensure the lens of the in-furnace monitoring device to extend into and exit the water-cooled wall of the furnace, and ensure that the in-furnace monitoring device 7 and the water-cooled wall are always arranged at a certain angle, the lens of the in-furnace monitoring device faces the adjacent water-cooled wall inside, and has cooling and self-cleaning functions, the lens of the in-furnace monitoring device has wide-area panoramic monitoring function and wear-resistant and high-temperature-resistant performance, the in-furnace monitoring device 7 is used to monitor the ash and slag accumulation condition of the adjacent water-cooled wall inside, the number is determined according to the area of the water-cooled wall in the wall-type soot blower or short soot blower area; when the furnace width is large, 8 sets are arranged in the same horizontal plane, arranged in axial symmetry, 2 sets are arranged on each side of the water-cooled wall, the distance from the intersection point of the monitoring center extension line of each set of in-furnace monitoring device to the water-cooled wall to the water-cooled wall where the device is located accounts for about 1 / 4 of the furnace width L; when the furnace width is small, 4 sets are arranged in the same horizontal plane, arranged in central symmetry, 1 set is arranged on each side of the water-cooled wall, for the four-corner tangential combustion boiler, the in-furnace monitoring device is arranged in the tangential direction, the distance from the intersection point of the monitoring center extension line of each set of device to the water-cooled wall to the water-cooled wall where the device is located accounts for about 1 / 2 of the furnace width L; when the water-cooled wall height in the wall-type soot blower or short soot blower area is large, two layers are arranged, and one layer is arranged when the height is small; the in-furnace monitoring device installation principle: first, it is conducive to overall monitoring, second, it is conducive to reducing the influence of flue gas ash on the monitoring line of sight, third, it is possible to use existing holes to reduce the water-cooled wall pipe.

[0174] Based on the real-time measurement data of the inner wall temperature measuring device, the local area pollution factor model of the furnace water-cooled wall is established, which is:

[0175]

[0176] wherein,

[0177] n is different sides of the furnace water-cooled wall, which can be represented by 1, 2, 3, 4 respectively for the left, right, front and back four sides of the furnace water-cooled wall, j is a local area of the water-cooled wall or a water-cooled wall area corresponding to the ash cleaner on different sides, Q Fsj , Q Fqj are the heat absorbed by the water-cooled wall area corresponding to the inner wall temperature measuring device in the actual state and in the cleaning state respectively, T rsj , T rqj are the temperatures of the water-cooled wall area corresponding to the inner wall temperature measuring device in the actual state and in the cleaning state respectively, σ0 is the Boltzmann constant, a sj , a qj are the furnace blackness of the water-cooled wall area corresponding to the inner wall temperature measuring device in the actual state and in the cleaning state respectively, s is the area of the water-cooled wall area corresponding to the inner wall temperature measuring device, C F is a dimensionless quantity, the larger the value, the more serious the pollution of the corresponding water-cooled wall area, and the pollution factor of different local areas of the water-cooled wall can be used as the pollution factor of the water-cooled wall area corresponding to the ash cleaner;

[0178] As Figure 1 , Figure 6 , Figure 7-1 , Figure 7-2 shown, in one embodiment, wall temperature measuring points 12 can also be provided on the water-cooled wall tube and the water-cooled wall fin to monitor the local temperature of the water-cooled wall, and a local pollution factor model of the water-cooled wall is established to determine the local pollution state of the water-cooled wall; the wall temperature measuring point 12 is composed of a wall temperature measuring point support 17, a tube wall temperature measuring point 18, a fin wall temperature measuring point 19, a fixed nut 20, a gasket 21 or a threaded nut 22, the tube wall temperature measuring point 18 and the fin wall temperature measuring point 19 are fixed on the wall temperature measuring point support through the fixed nut 20 and the gasket 21 or directly fixed through the threaded nut 22, the wall temperature measuring point support is fixed on the fin, the number of wall temperature measuring points is set according to the need for monitoring the pollution of the water-cooled wall in the area where the wall-type ash cleaner or the short ash cleaner is located, and is arranged in a grid shape, for the membrane-type water-cooled wall, the distance L between the tube wall temperature measuring point 18 and the fin wall temperature measuring point 19 in the wall temperature measuring point is S1 / 2±3, wherein S1 is the transverse pitch of the water-cooled wall tube.

[0179] The calculation method of the local area pollution factor of the water-cooled wall is based on the real-time measured temperature of the tube wall temperature measuring point and the fin wall temperature measuring point in the wall temperature measuring point, heat flow coupling is carried out, and the local area pollution factor of the furnace water-cooled wall is established as follows:

[0180] C Fnj =1-Q fsj / Q fqj ,

[0181] wherein Q fsj = λ sj (T 2sj -T 1sj ), Q fqj = λ qj (T 2qj -T 1qj )

[0182] n is the different side of the furnace water wall, j is the local area of the water wall or the water wall area corresponding to the soot blower on the different side, Q fsj , Q fqj are the heat flow monitored in real time and the heat flow measured under the cleaning state, λ sj , λ qj are the actual heat flow coefficient of the local area of the water wall or the water wall area corresponding to the soot blower and the heat flow coefficient under the cleaning state, T 2sj T 2qj are the actual temperature of the fin wall temperature measuring point and the temperature under the cleaning state of the fin wall temperature measuring point of the wall temperature measuring point of the local area of the water wall or the water wall area corresponding to the soot blower, T 1sj , T 1qj are the actual temperature of the tube wall temperature measuring point and the temperature under the cleaning state of the tube wall temperature measuring point of the wall temperature measuring point of the local area of the water wall or the water wall area corresponding to the soot blower, C f is dimensionless;

[0183] Based on the pollution factor of the local area of the water wall or the local area of the water wall corresponding to the soot blower, the average pollution factor of the single-side water wall is obtained, which is:

[0184]

[0185] wherein C Fnj is the pollution factor of the local area of the furnace water wall, m is the number of the monitored local area of the furnace water wall, n is the different side of the furnace water wall, when n is 1, 2, 3, 4, it can represent the left, right, front and rear four sides of the furnace water wall respectively, and j is the local area of the water wall or the water wall area corresponding to the soot blower on the different side;

[0186] The overall average pollution monitoring model of the furnace water wall heating surface is obtained, and the overall average pollution factor of the furnace water wall is:

[0187]

[0188] wherein,

[0189]

[0190] x is the water wall angle coefficient, for the membrane water wall, x = 1; ζ is the water wall fouling coefficient, T afor the theoretical combustion temperature, for the average thermal effective coefficient of the hearth, M is a parameter considering the relative position of the highest temperature of the flame in the furnace, a constant representing the center position of the flame, σ0 is the Boltzmann constant, a l for the blackness of the hearth, which is a hypothetical blackness representing the effective radiation of the flame; F lt for the hearth area, for the heat retention coefficient of the hearth, B j for the calculated fuel quantity of the boiler, for the average heat capacity of the combustion products, θ" lt for the flue gas temperature at the outlet of the hearth, which is obtained by back-calculation or direct monitoring of the flue gas temperature at the outlet of the economizer or other heating surface;

[0191] The overall average pollution factor of the water-cooled wall can also be calculated based on the average pollution factor of the single-side water-cooled wall, which is:

[0192]

[0193] wherein, for the average pollution factor of the single-side water-cooled wall, n is the number of different sides of the water-cooled wall of the hearth, when the water-cooled wall of the hearth has four sides, n is 4, when it has six or eight sides, n is 6 or 8;

[0194] In one embodiment, the pollution factor values of the local area of the water-cooled wall, the overall average pollution factor of the water-cooled wall, and the average pollution factor of the single-side water-cooled wall are integrated, coupled with the main operating parameters of the boiler, and at the same time, the areas where the water-cooled wall wall-type soot blower or short soot blower is located are monitored and judged and verified for local pollution by the in-furnace monitoring device, forming a pollution monitoring and optimization soot blowing method for the overall water-cooled wall, single-side water-cooled wall, and local area of the corresponding soot blower of the hearth. During soot blowing, the relationship between pollution and soot blowing and ash accumulation time of the overall water-cooled wall, single-side water-cooled wall, and local area determined in the soot blowing test is combined, the soot blowing time limit is set, and the water-cooled wall, single-side, and local area are comprehensively judged for soot blowing in combination with the soot blowing economic model, soot blowing safety model, and soot blowing comprehensive evaluation.

[0195] According to the arrangement position and heat transfer condition of the boiler heating surface, the boiler heating surface is classified, and different heating surface pollution factor calculation methods are provided. The same kind and different kind of heating surfaces in the boiler, and the same kind and different side of the heating surface are calculated and modeled respectively or as a whole according to the needs and the arrangement and heating condition of the boiler: the heating surface mainly by convection heat transfer is taken as the convection heating surface, such as the first re-heater of the tower type boiler, the economizer, the transition zone of the boiler, the evaporation heating surface, the air preheater, and the last stage superheater of the ∏ type boiler, that is, the high superheater, the last stage re-heater, that is, the high re-heater, the first stage superheater, that is, the low superheater, the economizer, the transition zone of the boiler, the evaporation heating surface, and the air preheater; the heating surface with radiation heat transfer and convection heat transfer in the same order of magnitude is taken as the semi-radiation semi-convection heating surface, such as the second re-heater of the tower type boiler, that is, the high temperature re-heater, the second stage superheater, that is, the medium temperature superheater, and the partition screen superheater or large screen superheater of the ∏ type boiler, the rear screen superheater or rear screen re-heater; the heating surface mainly by radiation heat transfer is taken as the full radiation heating surface, such as the third stage superheater of the tower type boiler, that is, the high superheater, the first stage superheater, that is, the low superheater, and the front screen superheater of the ∏ type boiler, the wall type re-heater, and the boiler heating surface within the furnace outlet window; based on the classification of the boiler heating surface and the needs, the pollution factor of the boiler heating surface is calculated and modeled, such as the left side and the right side of the high temperature re-heater of the tower type boiler, or the left side and the right side of the low temperature re-heater, which are calculated and modeled respectively according to the left side and the right side of the heating surface, so as to avoid partial burning and realize accurate control. The left side and the right side can also be combined as a whole to calculate the pollution factor and establish the model, so as to realize overall control; the low temperature superheater and the low temperature re-heater which are both convection heating surfaces in the ∏ type boiler can be taken as a whole to calculate the pollution factor and establish the model; the whole or part of the boiler water wall can be taken as a full radiation heating surface, and the pollution monitoring model can be established respectively.

[0196] No matter whether the solid fuel is used, the tube bundle is arranged in staggered arrangement, or the solid fuel is used, the tube bundle is arranged in in-line arrangement, and the gas fuel and the heavy oil are used (no matter whether it is staggered or in-line), the pollution factor of the convection heating surface is:

[0197] A calculation method is that,

[0198]

[0199] Wherein, α1=ζ(α d +α f ),

[0200] D is the flow of steam and water through the heating surface, Δh is the enthalpy rise of steam and water between the outlet and inlet of the heating surface, α1 is the heat release coefficient of the flue gas side non-ash flow washing the clean tube wall, α2 is the heat release coefficient of steam and water to the metal surface in the tube, A is the heat exchange area of the heating surface, Δt is the heat transfer temperature difference, ζ is the correction coefficient related to the uniformity of flue gas washing the heating surface; α d is the convective heat release coefficient of flue gas to the tube wall surface of the heating surface, α f is the radiative heat release coefficient of flue gas to the tube wall of the heating surface;

[0201] A calculation method is,

[0202]

[0203] wherein, α1 = ζ (α d + α f ),

[0204] φ is the boiler heat retention coefficient of the corresponding section of the heating surface, ΔH is the enthalpy drop of flue gas between the inlet and outlet of the flue gas side of the heating surface, B j is the calculated fuel quantity of the boiler, α1 is the heat release coefficient of the flue gas side non-ash flow washing the clean tube wall, α2 is the heat release coefficient of steam and water to the metal surface in the tube, ζ is the correction coefficient related to the uniformity of flue gas washing the heating surface; α d is the convective heat release coefficient of flue gas to the tube wall surface of the heating surface, α f is the radiative heat release coefficient of flue gas to the tube wall of the heating surface, A is the heat exchange area of the heating surface, Δt is the heat transfer temperature difference;

[0205] A calculation method is,

[0206]

[0207] wherein, α1 = ζ (α d + α f ),

[0208] K sj is the actual heat exchange coefficient of the heating surface, K qj is the clean heat exchange coefficient of the heating surface, B j is the calculated fuel quantity of the boiler, α1 is the heat release coefficient of the flue gas side non-ash flow washing the clean tube wall, α2 is the heat release coefficient of steam and water to the metal surface in the tube, A is the heat exchange area of the heating surface, Δt is the heat transfer temperature difference, Q sj is the heat absorbed by steam and water, D is the flow of steam and water through the heating surface, Δh is the enthalpy rise of steam and water between the outlet and inlet of the heating surface, ζ is the correction coefficient related to the uniformity of flue gas washing the heating surface; α d is the convective heat release coefficient of flue gas to the tube wall surface of the heating surface, α f is the radiative heat release coefficient of flue gas to the tube wall of the heating surface;

[0209] When solid fuel is used and the tube bundle is arranged in staggered pattern, a calculation method for the pollution factor of the convection superheater and reheater heating surface is,

[0210]

[0211] wherein, α1=ζ(α d +α f ), K sj is the actual heat transfer coefficient of the heating surface, B j is the calculated fuel quantity of the boiler, α1 is the heat release coefficient of the clean tube wall washed by the ash-free gas flow on the flue gas side, α2 is the heat release coefficient of the metal surface inside the tube washed by the steam and water, A is the heat transfer area of the heating surface, Δt is the temperature difference for heat transfer, Q sj is the heat absorbed by the steam and water, D is the steam and water flow passing through the heating surface, Δh is the enthalpy rise of the steam and water between the outlet and the inlet of the heating surface, ε is the thermal resistance caused by the ash in the flue gas and the ash and slag layer on the tube wall, ζ is the correction coefficient related to the uniformity of the flue gas washing the heating surface; α d is the convective heat release coefficient of the flue gas to the tube wall surface of the heating surface, α f is the radiative heat release coefficient of the flue gas to the tube wall of the heating surface.

[0212] When solid fuel is used and the tube bundle is arranged in in-line pattern, and when gas fuel and heavy oil (whether in staggered or in-line pattern) are used, a calculation method for the pollution factor of the convection heating surface is,

[0213]

[0214] wherein,

[0215] K sj is the actual heat transfer coefficient of the heating surface, B j is the calculated fuel quantity of the boiler, α1 is the heat release coefficient of the clean tube wall washed by the ash-free gas flow on the flue gas side, α2 is the heat release coefficient of the metal surface inside the tube washed by the steam and water, A is the heat transfer area of the heating surface, Δt is the temperature difference for heat transfer, Q sj is the heat absorbed by the steam and water, ψ is the thermal effective coefficient, indicating the coefficient related to the actual heat transfer coefficient and the clean heat transfer coefficient of the heating surface; ζ is the correction coefficient related to the uniformity of the flue gas washing the heating surface; α d is the convective heat release coefficient of the flue gas to the tube wall surface of the heating surface, α f is the radiative heat release coefficient of the flue gas to the tube wall of the heating surface.

[0216] When burning solid fuel, the tube bundle is arranged in a staggered manner, and when burning solid fuel, the tube bundle is arranged in a straight line, and when burning gas fuel and heavy oil (whether staggered or straight), the economizer, the transition zone of the once-through boiler, the evaporation heating surface, and the heating surface of the supercritical pressure boiler are taken as the convection heating surface, the pollution factor:

[0217] A calculation method is,

[0218]

[0219] Wherein, α1=ζ(α d +α f ),

[0220] D is the steam-water flow through the heating surface, Δh is the steam-water enthalpy rise between the outlet and the inlet of the heating surface, A is the heat exchange area of the heating surface, Δt is the heat transfer temperature difference, α1 is the heat release coefficient of the clean tube wall flushing by the ash-free gas flow on the flue gas side, ζ is the correction coefficient related to the uniformity of the flue gas flushing the heating surface; α d is the convective heat release coefficient of the flue gas to the surface of the heating surface tube wall, and α f is the radiative heat release coefficient of the flue gas to the heating surface tube wall.

[0221] A calculation method is,

[0222]

[0223] Wherein, α1=ζ(α d +α f ),

[0224] φ is the boiler heat retention coefficient corresponding to the area of the heating surface, ΔH is the flue gas enthalpy drop between the inlet and the outlet of the heating surface, B j is the calculated fuel quantity of the boiler, A is the heat exchange area of the heating surface, Δt is the heat transfer temperature difference, α1 is the heat release coefficient of the clean tube wall flushing by the ash-free gas flow on the flue gas side, α1 is the heat release coefficient of the clean tube wall flushing by the ash-free gas flow on the flue gas side, ζ is the correction coefficient related to the uniformity of the flue gas flushing the heating surface; α d is the convective heat release coefficient of the flue gas to the surface of the heating surface tube wall, and α f is the radiative heat release coefficient of the flue gas to the heating surface tube wall.

[0225] When burning solid fuel, the tube bundle is arranged in a staggered manner, and when burning solid fuel, the tube bundle is arranged in a straight line, and when burning gas fuel and heavy oil (whether staggered or straight), the economizer, the transition zone of the once-through boiler, the evaporation heating surface, and the heating surface of the supercritical pressure boiler are taken as the convection heating surface, the pollution factor,

[0226]

[0227] Wherein,

[0228] Ksj is the actual heat transfer coefficient of the heating surface, ε is the thermal resistance caused by the ash in the flue gas and the ash layer on the tube wall, B j is the calculated fuel quantity of the boiler, A is the heat transfer area of the heating surface, Δt is the temperature difference of the heat transfer of the heating surface, Q sj is the heat absorbed by the steam and water, α1 is the heat release coefficient of the ash-free gas flow on the flue gas side to the clean tube wall, α2 is the heat release coefficient of the steam and water to the metal surface in the tube, ζ is the correction coefficient related to the uniformity of the flue gas to the heating surface; α d is the convective heat release coefficient of the flue gas to the tube wall surface of the heating surface, α f is the radiative heat release coefficient of the flue gas to the tube wall of the heating surface;

[0229] When solid fuel is used, the tube bundle is arranged in line, and when gas fuel and heavy oil (whether staggered or in line) are used, the economizer, the transition zone of the once-through boiler, the evaporation heating surface, and the heating surface of the supercritical pressure boiler are taken as the convective heating surface, the pollution factor, one calculation method is,

[0230]

[0231] wherein, α1 = ζ (α d + α f ),

[0232] ψ is the thermal effective coefficient, which represents the coefficient related to the actual heat transfer coefficient of the heating surface and the clean heat transfer coefficient; K sj is the actual heat transfer coefficient of the heating surface, α1 is the heat release coefficient of the ash-free gas flow on the flue gas side to the clean tube wall, Q sj is the heat absorbed by the steam and water, B j is the calculated fuel quantity of the boiler, A is the heat transfer area of the heating surface, Δt is the temperature difference of the heat transfer of the heating surface, α2 is the heat release coefficient of the steam and water to the metal surface in the tube, ζ is the correction coefficient related to the uniformity of the flue gas to the heating surface; α d is the convective heat release coefficient of the flue gas to the tube wall surface of the heating surface, α f is the radiative heat release coefficient of the flue gas to the tube wall of the heating surface;

[0233] The pollution factor of the semi-radiative and semi-convective heating surface is:

[0234] One calculation method is,

[0235]

[0236] wherein,

[0237]

[0238]

[0239] Ksj K is the actual heat transfer coefficient of the heating surface qj Q is the heat transfer coefficient of the heating surface corresponding to the clean state sj B is the actual heat absorbed by the heating surface j H is the heat transfer area of the heating surface, and Δt is the actual temperature difference of the heating surface fqj Q is the radiation heat absorbed by the heating surface corresponding to the clean state dqj D is the steam-water flow rate through the heating surface, i" and i' are the outlet enthalpy and inlet enthalpy of the steam-water corresponding to the clean state of the heating surface, and α1 and α2 are the heat release coefficients of the clean tube wall and the metal surface inside the tube, respectively

[0240] A calculation method is

[0241]

[0242] wherein D is the steam-water flow rate through the heating surface, Δh sj B is the actual enthalpy rise of the steam-water between the outlet and the inlet of the heating surface sj H is the heat transfer area of the heating surface, and ΔT j B is the actual temperature difference of the heating surface qj H is the heat transfer area of the heating surface, and Δh fql Q is the radiation heat absorbed by the heating surface corresponding to the clean state, and α1 and α2 are the heat release coefficients of the clean tube wall and the metal surface inside the tube, respectively

[0243] A calculation method is

[0244]

[0245] wherein, is the heat retention coefficient, ΔH sj Q is the actual enthalpy drop of the flue gas between the inlet and the outlet of the heating surface fsj H is the heat transfer area of the heating surface, and ΔT sj B is the actual radiation heat absorbed by the heating surface, H is the heat transfer area of the heating surface, and ΔT fqj Q is the radiation heat absorbed by the heating surface corresponding to the clean state, and α1 and α2 are the heat release coefficients of the clean tube wall and the metal surface inside the tube, respectively qj ΔH is the enthalpy drop of the flue gas between the inlet and the outlet of the heating surface under the clean state

[0246] A calculation method is

[0247]

[0248] wherein,

[0249] K sj is the actual heat transfer coefficient of the heating surface, ε is the ash fouling coefficient caused by the ash in the flue gas and the thermal resistance caused by the ash fouling layer of the heating surface; Q fsj is the actual radiation heat absorption of the heating surface, Q dsj is the actual flue gas convection heat release absorbed by the heating surface, Q sj is the actual heat absorbed by the heating surface of the steam and water, H is the heat transfer area of the heating surface, ΔT sj is the actual temperature and pressure of the heating surface, α1 is the flue gas side heat release coefficient of the ash-free gas flow against the clean tube wall, and α2 is the heat release coefficient of the steam and water against the metal surface in the tube;

[0250] One calculation method is,

[0251]

[0252] wherein, B j is the calculated fuel quantity of the boiler, Q fsj is the actual radiation heat absorption of the heating surface, D is the steam and water flow through the heating surface, Δh is the steam enthalpy rise between the outlet and the inlet of the heating surface, H is the heat transfer area of the heating surface, ΔT is the actual temperature and pressure of the heating surface, α1 is the flue gas side heat release coefficient of the ash-free gas flow against the clean tube wall, and α2 is the heat release coefficient of the steam and water against the metal surface in the tube;

[0253] One calculation method is,

[0254]

[0255] wherein, φ is the boiler heat retention coefficient of the section where the heating surface is located, ΔH is the actual flue gas enthalpy drop between the inlet and the outlet of the heating surface, Q fsj is the actual radiation heat absorption of the heating surface, H is the heat transfer area of the heating surface, ΔT is the heat transfer temperature and pressure of the heating surface, α1 is the flue gas side heat release coefficient of the ash-free gas flow against the clean tube wall, and α2 is the heat release coefficient of the steam and water against the metal surface in the tube;

[0256] For the pollution factor calculation formula of the semi-radiation semi-convection heating surface, α1:

[0257] When the semi-radiation semi-convection heating surface is a screen heating surface or a tube heating surface, α1 is,

[0258]

[0259] wherein, α d is the flue gas side convection heat release coefficient calculated according to the outer surface area of the heating surface tube, s pz is the longitudinal pitch of the screen or tube heating surface, x pis the angular coefficient of the screen or tube heating surface, d is the outer diameter of the heating surface tube, α f is the radiation heat release coefficient of the flue gas to the tube wall, ζ is the utilization coefficient, which is the coefficient that reduces the heat due to incomplete flushing of the screen;

[0260] When the semi-radiation and semi-convection heating surface is a tubular heating surface, α1 can also be calculated according to the following formula:

[0261] α1=ζ(α d +α f )

[0262] Among them, α1 is the heat release coefficient of the ash-free airflow on the flue gas side scouring the unclean pipe wall, α d is the convection heat release coefficient of flue gas to the tube wall surface, α f is the radiation heat release coefficient of flue gas to the pipe wall.

[0263] Calculation of radiation heat absorption of semi-radiation and semi-convection heating surface:

[0264] (1) Ideal radiation heat Q of the first semi-radiation and semi-convection heating surface at the furnace outlet in a clean state fqj , the calculation method is as follows:

[0265]

[0266] in,

[0267]

[0268] Q flqj It is the radiation heat absorbed by the inlet cross-sectional area of ​​the first semi-radiation heating surface near the furnace outlet in a clean state.

[0269] Q f1qj is the heat radiated from the furnace and the first semi-radiant heating surface and the flue gas in between to the second heating surface behind the flue gas process in a clean state, η g is the coefficient of uneven heat load at the furnace outlet window; β is the correction coefficient considering the mutual radiation effect between the furnace and the first semi-radiation heating surface; q H is the average heat load of the furnace radiation heating surface, The effective radiation heating surface of the furnace absorbs heat for 1 kg of fuel, A lf is the total effective radiation heating area of ​​the furnace, B j Calculated fuel quantity for boiler, F l ″ is the cross-sectional area of ​​the furnace outlet smoke window, a1 is the smoke blackness between the first semi-radiation heating surfaces; x″ gr1 F″ is the angular coefficient of the inlet section to the outlet section of the first semi-radiant heating surface; gr1 is the flue gas outlet area of ​​the first semi-radiant heating surface, T gr1is the average temperature of the flue gas between the first semi-radiation heating surface, ξ r is the correction coefficient considering the fuel type, for coal ξ r = 0.5;

[0270] is the actual radiation heat of the first semi-radiation semi-convection heating surface at the furnace outlet, Q fsj is calculated in the same way as the ideal radiation heat Q fqj in the clean state, according to the parameters in the actual state;

[0271] (2) For the second heating surface behind the flue gas flow of the first semi-radiation heating surface at the furnace outlet, the radiation heat absorbed in the clean state Q f2qj is calculated by,

[0272]

[0273] wherein,

[0274] Q" f1qj is the heat radiated from the furnace and the first semi-radiation heating surface to the second heating surface behind the flue gas flow in the clean state, Q" f2qj is the heat radiated from the second semi-radiation heating surface and its flue gas to the third heating surface behind the flue gas flow in the clean state, β2 is the correction coefficient considering the mutual radiation influence between the first semi-radiation heating surface and the second heating surface behind the flue gas flow; a2 is the flue gas blackness between the second heating surface; x" gr2 is the angular coefficient of the second heating surface inlet cross section to the outlet cross section; F" gr2 is the flue gas outlet area of the second heating surface, T" gr2 is the average temperature of the flue gas between the second heating surface, ξ r2 is the correction coefficient considering the fuel type, B j boiler calculation fuel quantity;

[0275] For the second heating surface behind the flue gas flow of the first semi-radiation heating surface at the furnace outlet, the actual absorbed radiation heat Q f2sj is calculated in the same way as the radiation heat absorbed in the clean state Q f2qj , according to the parameters in the actual state.

[0276] In one embodiment, the pollution factor calculation formula of the full-radiation heating surface, one calculation method is,

[0277]

[0278] wherein,

[0279] D is the evaporative capacity of the total radiation heating surface, Δh is the enthalpy rise of steam between the outlet and the inlet of the total radiation heating surface, A p ζ is the effective radiation area of the total radiation heating surface p η is the soiling absorption coefficient of the total radiation heating surface i is the radiation heat absorption distribution coefficient of the total radiation heating surface q is the effective radiation heat intensity of the total radiation heating surface H is the average heat load of the total radiation heating surface of the furnace A is the heat absorption of the effective radiation heating surface of the furnace per 1 kg of fuel lf B is the total effective radiation heating area of the furnace j is the calculated fuel quantity of the boiler

[0280] The pollution factor of the air preheater as a convection heating surface, whether it is a tubular air preheater or a rotary air preheater, one calculation method is

[0281]

[0282] wherein,

[0283] respectively, the actual conversion differential pressure of the air preheater, the conversion differential pressure under the clean state, O 2，xgyy sj , O 2，0gy sj respectively, the oxygen content in the dry flue gas under the actual working condition and the actual conversion working condition, MW x sj , MW0 sj respectively, the generator power under the actual working condition and the actual conversion working condition, O 2，xgy qj , O 2，0gy qj respectively, the oxygen content in the dry flue gas under the clean working condition and the clean conversion working condition, the actual conversion working condition is the working condition under the rated power and a certain dry flue gas oxygen content in the actual pollution state; MW x qj , MW0 qj respectively, the generator power under the clean working condition and the clean conversion working condition, the clean conversion working condition is the working condition under the rated power and a certain dry flue gas oxygen content in the clean working condition;

[0284] For a tubular air preheater, the pollution factor, one calculation method is

[0285]

[0286]

[0287] K sjkK qjk actual heat transfer coefficient of air preheater, and α1, α2 are heat release coefficient of flue gas and air of air preheater, respectively, B d heat absorbed by air of air preheater, A is heat transfer outer surface area of air preheater, Δt is temperature difference of heat transfer of air preheater, and ζ is utilization coefficient, representing comprehensive influence coefficient of dust fouling and incomplete flushing of heat transfer surface of air preheater; j boiler calculated fuel quantity;

[0288] For tubular air preheater, the pollution factor is calculated by one method as follows:

[0289]

[0290] wherein,

[0291]

[0292] K sjk actual heat transfer coefficient of air preheater, and α1, α2 are heat release coefficient of flue gas and air of air preheater, respectively, B

[0293] For rotary air preheater, the pollution factor is calculated by one method as follows:

[0294]

[0295] wherein,

[0296]

[0297] K sjk actual heat transfer coefficient of air preheater, and C is non-steady heat transfer influence coefficient caused by change of rotating speed; x y , x k are share of flue gas and air flushing rotor, respectively, and α1, α2 are heat release coefficient of flue gas and air of air preheater, respectively, B

[0298] For rotary air preheater, the pollution factor is calculated by one method as follows:

[0299]

[0300] wherein,

[0301] K sjk , K qjk actual and clean state heat transfer coefficient of air preheater, respectively, and C is non-steady heat transfer influence coefficient caused by change of rotating speed; x y, x k respectively are the share of flue gas and air scouring rotor; a1, a2 are respectively the air preheater heat transfer coefficient of flue gas and air;

[0302] Whether it is a tubular air preheater or a rotary air preheater, the actual heat transfer coefficient is,

[0303]

[0304] wherein,

[0305]

[0306] β" ky Excess air ratio of air preheater outlet air; Δa ky Air leakage coefficient of air preheater air leakage to flue gas measurement; Theoretical air enthalpy value on the air preheater air outlet and inlet section respectively, B j The calculated fuel quantity of the boiler, Δt is the logarithmic mean temperature and pressure, Δt d The medium temperature difference of the end with larger temperature difference in the air preheater heating surface, Δt x The medium temperature difference of the end with smaller temperature difference in the air preheater heating surface, A is the air preheater heat transfer area.

[0307] As an aspect of the method for monitoring and cleaning the ash pollution of the heating surface of a power station boiler, the method for establishing the cleaning economic model is: the method for establishing the cleaning economic model is: combined with the boiler steam cleaning field test, according to the quantitative influence data of the cleaning action on the main steam temperature, the reheat steam temperature and the exhaust gas temperature under different working conditions measured by the control variable method, the comprehensive influence on the boiler efficiency is represented as the basis for the system economic evaluation; at the same time, the cleaning consumption and the cleaning benefit are comprehensively considered, which specifically includes:

[0308] (1) According to the field experiment, the influence model of each group of ash cleaner action on the boiler efficiency under different loads is established, such as the action benefit of each group of ash cleaner is the heat transfer capacity improvement brought by the cleaning of each group of ash cleaner, that is, the boiler efficiency and benefit improvement;

[0309] (2) According to the operation parameters, the operation consumption cost model of each group of ash cleaner is established, such as the operation consumption cost of each group of ash cleaner = steam consumption of each ash cleaner per cleaning × total input of each group of ash cleaner within a certain time × unit steam consumption and power consumption cost;

[0310] (3) Establishing the ash cleaning economic model of each group of ash cleaning device to realize the economic optimization of ash cleaning operation, such as the comprehensive economic benefit = the increase of the income brought by the ash cleaning of each group of ash cleaning device - the operation consumption cost + the steam consumption and the electric consumption cost saved by reducing the ash cleaning frequency + the labor operation cost and the equipment maintenance cost saved + the safety benefit brought by reducing the blowing of the boiler heating surface + the environmental protection benefit brought by reducing the waste gas emission, which is maximized under the premise of ensuring the safety of the operation parameters;

[0311] The ash cleaning economic model optimization logical diagram of the application is shown in Figure 8

[0312] As an aspect of the ash cleaning method of the application, the method for establishing the ash cleaning safety model is as follows:

[0313] 1) The ash cleaning frequency of each ash cleaning device per day cannot be higher than the set upper limit, such as the ash cleaning of each ash cleaning device not more than three times per day;

[0314] 2) The ash cleaning frequency of each ash cleaning device within a certain time cannot be lower than the lower limit, such as the ash cleaning of each ash cleaning device not less than five times per week;

[0315] 3) Ensuring that the main steam temperature and the reheat steam temperature are not overheated or underheated is an important condition for the intelligent ash cleaning, such as setting that the highest main steam temperature is not higher than the design temperature by 3℃ and the lowest main steam temperature is not lower than the design temperature by 5℃; setting that the highest reheat steam temperature is not higher than the design temperature by 3℃ and the lowest reheat steam temperature is not lower than the design temperature by 4℃;

[0316] 4) Setting the low load limit value of the ash cleaning operation, such as setting that the ash cleaning is not performed below 30% rated load or 25% rated load;

[0317] 5) Setting that the ash cleaning device action and state signal enters the DCS, and when the signal is not normal, the ash cleaning device is immediately exited.

[0318] As an aspect of the ash cleaning method of the application, the method for establishing the ash cleaning comprehensive evaluation model is as follows: the ash cleaning economic model and the ash cleaning safety model are comprehensively established to form the ash cleaning comprehensive evaluation model, the ash cleaning is timely suspended or stopped by real-time acquisition of the boiler operation parameters and setting of the ash cleaning safety limit condition, and the economy is evaluated by comprehensively considering the ash cleaning steam consumption, electric consumption, income, steam temperature, exhaust gas temperature and frequency.

[0319] ​As an aspect of the method for intelligent monitoring and cleaning of the heating surface of a power plant boiler, the method for establishing the closed-loop control model is as follows: control logic is established in the intelligent server or DCS system, and the accurate monitoring data of the pollution state of the overall, single side and local area of the boiler heating surface and water wall, comprehensive evaluation information of cleaning and safety information are integrated into the control program; including: the overall, single side and local area of the furnace water wall, the convection heating surface, the full radiation, the semi-radiation and semi-convection heating surface and the air preheater, and according to the pollution factor model and the grouping of the cleaning device, and the safety, economic and comprehensive judgment of the cleaning is included in the control program; the established control program can realize the optimized control of the cleaning device according to the modeling and grouping of the heating surface, and the independent control of the single cleaning device, realize the control of the boiler heating surface, different sides, the overall, single side and local area of the water wall, realize the on-demand, economic and safe cleaning; at the same time, the control logic of the existing cleaning device is retained, and the interlocking and switching conditions of the closed-loop control model and the existing cleaning device control logic and the intelligent cleaning start button are set to ensure the normal and safe switching and operation of the two cleaning methods;

[0320] As an aspect of the method for intelligent monitoring and cleaning of the heating surface of a power plant boiler, the method for establishing the closed-loop control model is as follows: control logic is established in the intelligent server or DCS system, and the accurate monitoring data of the pollution state of the overall, single side and local area of the boiler heating surface and water wall, comprehensive evaluation information of cleaning and safety information are integrated into the control program; including: the overall, single side and local area of the furnace water wall, the convection heating surface, the full radiation, the semi-radiation and semi-convection heating surface and the air preheater, and according to the pollution factor model and the grouping of the cleaning device, and the safety, economic and comprehensive judgment of the cleaning is included in the control program; the established control program can realize the optimized control of the cleaning device according to the modeling and grouping of the heating surface, and the independent control of the single cleaning device, realize the control of the boiler heating surface, different sides, the overall, single side and local area of the water wall, realize the on-demand, economic and safe cleaning; at the same time, the control logic of the existing cleaning device is retained, and the interlocking and switching conditions of the closed-loop control model and the existing cleaning device control logic and the intelligent cleaning start button are set to ensure the normal and safe switching and operation of the two cleaning methods;

[0321] When the mouse is at the soot blower number, the left button is clicked to operate the soot blower, and the right button is clicked to display the state of the corresponding soot blower. When the mouse is at the drain valve button, the left button is clicked to operate the drain valve, and the right button is clicked to display the state of the drain valve. When the mouse is at the main steam valve button, the left button is clicked to operate the main steam valve, and the right button is clicked to display the state of the main steam valve. When the mouse is at the auxiliary steam valve, the left button is clicked to operate the auxiliary steam valve, and the right button is clicked to display the state of the auxiliary steam valve. When the mouse is at the in-furnace monitoring device number, the corresponding monitoring data is displayed. When the mouse is at the inner wall temperature measuring device or wall temperature measuring point number, the corresponding monitoring data is displayed. When the mouse is at the intelligent soot blowing start button, the left button is clicked to realize the intelligent soot blowing closed-loop control linkage and unlocking. When unlocked, the intelligent soot blowing control program is interrupted, and can be linked with the original soot blowing program to realize the interactive use of the intelligent soot blowing program and the original soot blowing program.

[0322] As Figure 1According to another aspect of the present application, an intelligent monitoring and closed-loop control system for the heating surface of a power plant boiler is provided, comprising: inner wall temperature measuring device 9 or wall temperature measuring point 12, furnace endoscopic monitoring device 7, including data collector 11, compensation wire 10, communication cable 5, switch 1, optical fiber or communication cable 2, intelligent server 6, DCS system 3, DCS data interface card 4, and communication protocol. The inner wall temperature measuring device 9 or wall temperature measuring point 12 is arranged on the furnace water wall, and the furnace endoscopic monitoring device 7 is arranged on the furnace water wall. The tube wall temperature measuring point 18 and the fin wall temperature measuring point 19 in the inner wall temperature measuring device 9 or wall temperature measuring point 12 are connected to the data collector 11 through the compensation wire 10. Multiple data collectors are connected in series through the communication cable and then connected to the switch 1. The data measured by the tube wall temperature measuring point 18 and the fin wall temperature measuring point 19 in the inner wall temperature measuring device 9 or wall temperature measuring point 12 are sent to the switch 1 through the data collector 11. The furnace endoscopic monitoring device 7 is connected to the switch 1 through the twisted pair or communication cable 8 for communication, and the video data is sent to the switch 1. The switch 1 is connected to the DCS system 3 through the optical fiber or communication cable 2, and the newly added measuring point data is sent to the DCS system 3. The data measured by the inner wall temperature measuring device 9 or wall temperature measuring point 12 and the furnace endoscopic monitoring device 7, and the measuring point equipment arranged in the heating surface area of the boiler as needed, are sent to the DCS system 3. The intelligent server 6 is connected to the DCS system 3 through the communication cable 5 to read and write data in OPC communication protocol, or connected through the communication cable 5 and the DCS data interface card 4 to read and write data in modbus communication protocol. A software model is established in the intelligent server 6, including various pollution factor calculation models, ash removal economic model, ash removal safety model, ash removal comprehensive evaluation model established according to the method provided in the present application, and data reading module, data preprocessing module, and intelligent ash removal database. A closed-loop control model and a monitoring and control screen are arranged in the intelligent server 6 or the DCS system 3. The intelligent server 6 reads data from the DCS system 3 through the data reading module, processes the data through the data preprocessing module, and sends the data to the intelligent ash removal database, the ash removal safety model, and the ash removal economic model. The pollution factor calculation model obtains data from the intelligent ash removal database and sends the calculated pollution factor data to the closed-loop control model and returns to the intelligent ash removal database. The ash removal safety model and the ash removal economic model send the operation results to the ash removal comprehensive evaluation model for comprehensive evaluation and send the comprehensive evaluation information to the closed-loop control model. The closed-loop control model processes the pollution factor data and the comprehensive evaluation information to realize the operation optimization control of the ash removal device. At the same time, the monitoring and control screen reads the pollution factor data from the intelligent ash removal database and obtains relevant parameters and equipment state information from the DCS system 3 for monitoring and control.

[0323] The present application has the positive beneficial effects that the present application provides a power plant boiler heating surface dust intelligent monitoring and cleaning method and closed-loop control system, which monitors and monitors the overall, single side and local area of the boiler heating surface and water cooling wall, optimizes the boiler heating surface pollution monitoring model and the cleaning method, realizes the overall consideration of safety and benefit of the boiler, and automatic closed-loop control.

Claims

1. A method for intelligent monitoring, supervising and soot blowing of heating surfaces of a power plant boiler, characterized in that Comprise: Providing a method of setting inner wall temperature measuring device or wall temperature measuring point on furnace water cooling wall, setting furnace endoscopic monitoring device, providing local area pollution factor based on water cooling wall temperature monitoring and inner wall pollution monitoring, providing calculation and pollution judgment method of single side water cooling wall average pollution factor and furnace water cooling wall overall average pollution factor, monitoring and monitoring water cooling wall overall, single side and local pollution state; According to the arrangement position and heat transfer state of boiler heating surface, different heating surfaces are divided into convection heating surface, semi-radiation semi-convection heating surface and full-radiation heating surface, and the same kind and different kind of heating surfaces and the same kind and different side of heating surfaces are calculated and modeled according to the actual heat exchange and pollution condition and need respectively or as a whole, so as to provide pollution monitoring method of boiler heating surface based on accurate classification, combination and need; Provide the establishment method of ash removal economic model, ash removal safety model, ash removal comprehensive evaluation model and closed loop control model, and provide monitoring monitoring monitoring picture, main information and control method, which constitutes the comprehensive judgment and monitoring monitoring monitoring method of boiler heating surface, furnace water cooling wall overall, single side and local area optimization ash removal. A plurality of inner wall temperature measuring devices and a plurality of in-furnace monitoring devices are arranged on the water-cooled wall fins between the wall-type soot blower or short soot blower and the water-cooled wall pipes, and a model of the overall average pollution factor of the water-cooled wall of the furnace, a model of the local area pollution factor and a model of the average pollution factor of the single-side water-cooled wall are established to monitor the pollution state; each inner wall temperature measuring device is fixed on the water-cooled wall fin by a fixing member or direct welding, or is fixed on a support by a fixing nut and a gasket, the support is fixed on the water-cooled wall fin, the hot end of the inner wall temperature measuring device extends into the inner wall of the fin through the opening on the water-cooled wall fin, is flush with the inner wall or slightly extends out of the inner wall of the water-cooled wall fin and is fixed on the inner wall of the fin, and is arranged between the wall-type soot blower or short soot blower, the plurality of inner wall temperature measuring devices are arranged in a grid shape on the four water-cooled walls respectively, the number is determined according to the number of the wall-type soot blower or short soot blower and the area of the water-cooled wall, the inner wall temperature measuring device is made of wear-resistant and high-temperature-resistant material, can measure the temperature range of 0-1300 DEG C or 0-1600 DEG C, and can use high-temperature-resistant and wear-resistant K-graduated thermocouple, platinum-rhodium 40-platinum thermocouple or high-temperature thermometer; each in-furnace monitoring device is arranged on the in-furnace monitoring device support near the corner of the furnace, the in-furnace monitoring device support is fixed on the water-cooled wall fin, has telescopic guide rails to ensure that the lens of the in-furnace monitoring device extends into and exits the water-cooled wall of the furnace, and ensures that the in-furnace monitoring device is arranged at a certain angle with the water-cooled wall at all times, the lens of the in-furnace monitoring device faces the inner side of the adjacent water-cooled wall and has cooling and self-cleaning functions, the lens of the in-furnace monitoring device has wide-area panoramic monitoring function and wear-resistant and high-temperature-resistant performance, and the in-furnace monitoring device is used to monitor the ash deposition and slagging condition of the inner side of the adjacent water-cooled wall, the number is determined according to the area of the water-cooled wall in the area where the wall-type soot blower or short soot blower is arranged; when the width of the furnace is large, 8 in-furnace monitoring devices are arranged in the same horizontal plane and are arranged in an axis-symmetrical manner, 2 in-furnace monitoring devices are arranged on each side of the water-cooled wall, the distance between the intersection of the monitoring center extension line of each in-furnace monitoring device and the water-cooled wall and the water-cooled wall where the in-furnace monitoring device is arranged accounts for about 1 / 4 of the width L of the furnace; when the width of the furnace is small, 4 in-furnace monitoring devices are arranged in the same horizontal plane and are arranged in a center-symmetrical manner, 1 in-furnace monitoring device is arranged on each side of the water-cooled wall, for the tangential circular combustion boiler, the in-furnace monitoring devices are arranged in the order of tangential circle, the distance between the intersection of the monitoring center extension line of each in-furnace monitoring device and the water-cooled wall and the water-cooled wall where the in-furnace monitoring device is arranged accounts for about 1 / 2 of the width L of the furnace; when the height of the water-cooled wall in the area where the wall-type soot blower or short soot blower is arranged is large, two layers of in-furnace monitoring devices are arranged, and when the height is small, one layer of in-furnace monitoring devices is arranged; the installation principle of the in-furnace monitoring device is: first, it is beneficial to the overall monitoring, second, it is beneficial to reducing the influence of flue gas and ash on the monitoring line of sight, and third, it is possible to utilize the existing holes to reduce the water-cooled wall pipe drawing; Based on the real-time measurement data of the inner wall temperature measuring device, a model of the local area pollution factor of the water-cooled wall of the furnace is established, which is wherein, n is the different side of the furnace water cooled wall, which can be represented by 1, 2, 3, 4 respectively for the left, right, front and back of the furnace water cooled wall, j is the local area of the water cooled wall or the water cooled wall area corresponding to the ash remover on the different side, Fsj , Q Fqj are the heat absorbed by the water cooled wall area corresponding to the inner wall temperature measuring device in the actual state and in the cleaning state respectively, T rsj , T rqj are the temperature of the water cooled wall area corresponding to the inner wall temperature measuring device in the actual state and in the cleaning state respectively, σ0 is the Boltzmann constant, a sj , a qj are the furnace blackness of the water cooled wall area corresponding to the inner wall temperature measuring device in the actual state and in the cleaning state respectively, s is the area of the water cooled wall area corresponding to the inner wall temperature measuring device, C F is a dimensionless quantity, the greater the value, the more serious the pollution of the corresponding water cooled wall area, the pollution factor of different local areas of the water cooled wall can be used as the pollution factor of the water cooled wall area corresponding to the ash remover; Or set up wall temperature measuring point on water-cooled wall tube and water-cooled wall fin, monitor local temperature of water-cooled wall, and establish local area pollution factor model of water-cooled wall to determine local pollution state of water-cooled wall; the wall temperature measuring point is composed of wall temperature measuring point support, tube wall temperature measuring point, fin wall temperature measuring point, fixing nut, gasket or threaded pair, the tube wall temperature measuring point and the fin wall temperature measuring point are fixed on the wall temperature measuring point support through the fixing nut, the gasket or directly through the threaded pair, the wall temperature measuring point support is fixed on the fin, the number of the wall temperature measuring point is set according to the need of pollution monitoring of the water-cooled wall in the area where the wall-type soot blower or the short soot blower is located, and is arranged in a grid shape, for the membrane-type water-cooled wall, the distance L between the tube wall temperature measuring point and the fin wall temperature measuring point in the wall temperature measuring point is (S1 / 2) ± 3, wherein S1 is the transverse pitch of the water-cooled wall tube; Based on the temperature measured in real time by the tube wall temperature measuring point and the fin wall temperature measuring point in the wall temperature measuring point, heat flow coupling is carried out, and the local area pollution factor of the furnace water-cooled wall is established, which is: C Fnj = 1 - Q fsj / Q fqj , where Q fsj = λ sj (T 2sj -T 1sj ), Q fqj = λ qj (T 2qj -T 1qj ) n is different side of the furnace water wall, j is the local area of the water wall or the water wall area corresponding to the soot blower on the different side, Q fsj , Q fqj are the heat flux monitored in real time and the heat flux measured in the cleaning state respectively, λ sj , λ qj are the actual heat flux coefficient and the heat flux coefficient in the cleaning state of the local area of the water wall or the water wall area corresponding to the soot blower respectively, T 2sj T 2qj are the actual temperature and the temperature in the cleaning state of the fin wall temperature measuring point of the wall temperature measuring point of the local area of the water wall or the water wall area corresponding to the soot blower, T 1sj , T 1qj are the actual temperature and the temperature in the cleaning state of the tube wall temperature measuring point of the wall temperature measuring point of the local area of the water wall or the water wall area corresponding to the soot blower, C f is a dimensionless quantity; Based on the pollution factor of the local area of the water-cooled wall or the local area of the water-cooled wall corresponding to the soot blower, the average pollution factor of the single-side water-cooled wall is obtained, which is: wherein C Fnj is the pollution factor of the local area of the furnace water wall, m is the number of the monitored local area of the furnace water wall, n is the different side of the furnace water wall, when n is 1, 2, 3, 4, it can represent the left, right, front and back four sides of the furnace water wall respectively, and j is the local area of the water wall or the corresponding water wall area of the ash remover on the different side. The overall average pollution monitoring model of the furnace water-cooled wall heating surface is the overall average pollution factor of the furnace water-cooled wall, which is: Wherein, x is the water wall angle factor, x = 1 for membrane water wall; ζ is the water wall fouling factor, T a is the theoretical combustion temperature, is the average thermal effective coefficient of the furnace, M is a parameter considering the relative position of the highest temperature of the flame in the furnace, a constant representing the central position of the flame, σ0 is the Boltzmann constant, a l is the furnace blackness, which is a hypothetical blackness representing the effective radiation of the flame; F lt is the furnace area, is the furnace heat retention coefficient, B j is the calculated fuel quantity of the boiler, is the average heat capacity of the combustion products, θ" lt is the flue gas temperature at the outlet of the furnace, which is obtained by back-calculation or direct monitoring of the flue gas temperature at the outlet of the economizer or other heating surface; Or based on the average pollution factor of the single-side water-cooled wall, the overall average pollution factor of the water-cooled wall is calculated, which is: wherein, n is the number of sides of the furnace water wall, and when the furnace water wall has four sides, n is 4, and when it has six or eight sides, n is 6 or 8. The local area pollution factor value of the water-cooled wall, the overall average pollution factor of the water-cooled wall, and the average pollution factor of the single-side water-cooled wall are comprehensively coupled with the main operation parameters of the boiler, and the area where the wall-type soot blower or the short soot blower is located is monitored and judged and verified in the local pollution through the furnace endoscopic monitoring device, forming the overall, single-side and local area pollution monitoring and monitoring and optimization soot blowing method of the furnace water-cooled wall; during soot blowing, the pollution and soot blowing, ash accumulation time of the overall, single-side and local area of the water-cooled wall determined in the soot blowing test are combined, the soot blowing time limit is set, and the water-cooled wall, single-side and local area are comprehensively judged through the soot blowing economic model, soot blowing safety model and soot blowing comprehensive evaluation.

2. The method of claim 1, wherein, According to the arrangement position and heat transfer condition of the boiler heating surface, the boiler heating surface is classified, and different heating surface pollution factor calculation methods are provided. The same kind and different kind of heating surface, and the same kind and different side of the heating surface in the boiler are calculated and modeled respectively or as a whole according to the needs and the arrangement and heating condition of the boiler. The heating surface mainly by convection heat transfer is taken as the convection heating surface, including the first re-heater, i.e. the low-temperature re-heater, the economizer, the transition zone of the boiler, the evaporation heating surface, and the air preheater of the tower type boiler, and the last-stage superheater, i.e. the high-temperature superheater, the last-stage re-heater, i.e. the high-temperature re-heater, the first-stage superheater, i.e. the low-temperature superheater, the first-stage re-heater, i.e. the low-temperature re-heater, the economizer, the transition zone of the boiler, the evaporation heating surface, and the air preheater of the ∏ type boiler. The heating surface with the radiation heat transfer and the convection heat transfer in the same order of magnitude is taken as the semi-radiation semi-convection heating surface, including the second re-heater, i.e. the high-temperature re-heater, and the second-stage superheater, i.e. the medium-temperature superheater of the tower type boiler, and the partition screen superheater or large screen superheater, and the rear screen superheater or rear screen re-heater of the ∏ type boiler. The heating surface mainly by radiation heat transfer is taken as the full-radiation heating surface, including the third-stage superheater, i.e. the high-temperature superheater, and the first-stage superheater, i.e. the low-temperature superheater of the tower type boiler, and the front screen superheater, the wall type re-heater, and the heating surface inside the outlet window of the furnace of the ∏ type boiler. Based on the classification and needs of the boiler heating surface, the pollution factor of the boiler heating surface is calculated and modeled, including the left side and the right side of the high-temperature re-heater or the left side and the right side of the low-temperature re-heater in the tower type boiler, which are calculated and modeled respectively according to the left side and the right side of the heating surface to avoid partial burning and realize precise control, or the left side and the right side are combined as a whole to calculate and model the pollution factor and realize overall control. The low-temperature superheater and the low-temperature re-heater, which are both convection heating surfaces in the ∏ type boiler, are taken as a whole to calculate and model the pollution factor. The whole or part of the boiler water wall is taken as the full-radiation heating surface, and the pollution monitoring model can be established as a whole, on one side or in part.

3. The method of claim 2, wherein, No matter whether the solid fuel is used, the tube bundle is arranged in staggered arrangement, or the solid fuel is used, the tube bundle is arranged in in-line arrangement, or the gas fuel and the heavy oil are used, and the tube bundle is arranged in staggered arrangement or in-line arrangement, the pollution factor of the convection heating surface is: One calculation method is that the pollution factor of the convection heating surface is calculated according to the pollution factor of the convection heating surface of the boiler using the solid fuel and arranged in staggered arrangement. wherein a1= ζ(a d + a f ), D is the steam-water flow through the heating surface, Ah is the steam-water enthalpy rise between the outlet and inlet of the heating surface, a1 is the heat release coefficient of the flue gas side non-ash flow to the clean tube wall flushing, a2 is the heat release coefficient of the steam to the metal surface in the tube, A is the heat exchange area of the heating surface, At is the heat transfer temperature difference, ζ is the correction coefficient related to the uniformity of the flue gas flushing the heating surface;ɑ d is the convective heat release coefficient of the flue gas to the heating surface tube wall surface, α f is the radiation heat release coefficient of the flue gas to the heating surface tube wall. One calculation method is that the pollution factor of the convection heating surface is calculated according to the pollution factor of the convection heating surface of the boiler using the solid fuel and arranged in in-line arrangement. wherein a1= ζ(α d + a f ), φ is the heat preservation coefficient of the corresponding section of the heating surface of the boiler, ΔH is the enthalpy drop of the flue gas between the inlet and outlet of the heating surface, B j is the fuel quantity calculated for the boiler, α1 is the heat release coefficient of the flue gas side ash-free gas flow to the clean tube wall, α2 is the heat release coefficient of the steam water to the metal surface in the tube, ζ is the correction coefficient related to the uniformity of the flue gas to the heating surface, α d is the convective heat release coefficient of the flue gas to the tube wall surface of the heating surface, α f is the radiative heat release coefficient of the flue gas to the tube wall of the heating surface, A is the heat exchange area of the heating surface, and Δt is the heat transfer temperature difference. One calculation method is that the pollution factor of the convection heating surface is calculated according to the pollution factor of the convection heating surface of the boiler using the gas fuel and the heavy oil and arranged in staggered arrangement. wherein a1= ζ(α d + a f ), K sj is the actual heat transfer coefficient of the heating surface, K qj is the clean heat transfer coefficient of the heating surface, B j is the calculated fuel quantity of the boiler, α1 is the heat release coefficient of the ash-free flue gas side on the cleaning of the tube wall, α2 is the heat release coefficient of the steam-water on the metal surface inside the tube, A is the heat transfer area of the heating surface, Δt is the heat transfer temperature difference, Q sj is the heat absorbed by the steam-water, D is the steam-water flow through the heating surface, Δh is the steam-water enthalpy rise between the outlet and the inlet of the heating surface, ζ is the correction coefficient related to the uniformity of the flue gas scouring the heating surface; α d is the convective heat release coefficient of the flue gas on the tube wall surface of the heating surface, α f is the radiative heat release coefficient of the flue gas on the tube wall of the heating surface; When the solid fuel is used, the tube bundle is arranged in staggered arrangement, and when the solid fuel is used, the tube bundle is arranged in in-line arrangement, or the gas fuel and the heavy oil are used, and the tube bundle is arranged in staggered arrangement or in-line arrangement, the pollution factor of the economizer, the transition zone of the straight-flow boiler, the evaporation heating surface, and the heating surface of the supercritical pressure boiler as the convection heating surface is: K sj is the actual heat transfer coefficient of the heating surface, B j is the calculated fuel quantity of the boiler, α1 is the heat release coefficient of the flue gas side ash-free gas flow to the clean tube wall scouring, α2 is the heat release coefficient of the steam water to the metal surface inside the tube, A is the heat transfer area of the heating surface, Δt 为 is the heat transfer temperature and pressure, Q sj is the heat absorbed by the steam water, D is the steam water flow through the heating surface, Δh is the steam water enthalpy rise between the outlet and the inlet of the heating surface, ε is the thermal resistance caused by the ash in the flue gas and the tube wall ash slag layer, ζ is the correction coefficient related to the uniformity of the flue gas scouring the heating surface; α d is the convective heat release coefficient of the flue gas to the tube wall surface of the heating surface, α f is the radiative heat release coefficient of the flue gas to the tube wall of the heating surface; One calculation method is that the pollution factor of the convection heating surface is calculated according to the pollution factor of the convection heating surface of the boiler using the solid fuel and arranged in staggered arrangement. wherein a1= ζ(α d + a f ), K sj is the actual heat transfer coefficient of the heating surface, B j is the calculated fuel quantity of the boiler, α1 is the heat release coefficient of the ash-free flue gas flow on the clean tube wall, α2 is the heat release coefficient of the steam-water to the metal surface in the tube, A is the heat transfer area of the heating surface, Δt is the heat transfer temperature difference, Q sj is the heat absorbed by the steam-water, ψ is the thermal effectiveness coefficient, which represents the coefficient related to the actual heat transfer coefficient of the heating surface and the clean heat transfer coefficient; ζ is the correction coefficient related to the uniformity of the flue gas scouring the heating surface; α d is the convective heat release coefficient of the flue gas to the tube wall surface of the heating surface, α f is the radiative heat release coefficient of the flue gas to the tube wall of the heating surface.

4. The method of claim 2, wherein, One calculation method is that the pollution factor of the convection heating surface is calculated according to the pollution factor of the convection heating surface of the boiler using the solid fuel and arranged in in-line arrangement. wherein a1= ζ(a d + a f ), D is the steam-water flow through the heating surface, Δh is the steam-water enthalpy rise between the outlet and inlet of the heating surface, A is the heat exchange area of the heating surface, Δt is the heat transfer temperature difference, α1 is the heat release coefficient of the flue gas side non-ash flow washing the clean tube wall, ζ is a correction coefficient related to the uniformity of the flue gas washing the heating surface;ɑ d is the convective heat release coefficient of the flue gas to the surface of the tube wall of the heating surface, α f is the radiative heat release coefficient of the flue gas to the tube wall of the heating surface. ​ wherein a1= ζ(a d + a f ), φ is the boiler heat retention coefficient of the corresponding area of the heating surface, ΔH is the flue gas enthalpy drop between the inlet and outlet of the heating surface, B j is the fuel quantity calculated for the boiler, A is the heat exchange area of the heating surface, Δt is the heat transfer temperature difference, α1 is the heat release coefficient of the clean tube wall scouring by the ash-free gas flow on the flue gas side, α1 is the heat release coefficient of the clean tube wall scouring by the ash-free gas flow on the flue gas side, ζ is the correction coefficient related to the uniformity of the flue gas scouring the heating surface;ɑ d is the convective heat release coefficient of the flue gas to the surface of the heating surface tube wall, α f is the radiative heat release coefficient of the flue gas to the heating surface tube wall; When the solid fuel is combusted, the tube bundles are arranged in staggered arrangement, the transition zone of economizer and once-through boiler, the evaporation heating surface and the heating surface of supercritical pressure boiler are taken as the convection heating surface, for the pollution factor of the half radiation and half convection heating surface, a calculation method is that, wherein a1= ζ(α d + a f ), K sj is the actual heat transfer coefficient of the heating surface, ε is the thermal resistance caused by the ash in the flue gas and the ash layer on the tube wall, B j is the calculated fuel quantity of the boiler, A is the heat transfer area of the heating surface, Δt is the temperature difference of the heating surface heat transfer, Q sj is the heat absorbed by the steam and water, α1 is the heat release coefficient of the ash-free gas flow on the flue gas side washing the clean tube wall, α2 is the heat release coefficient of the steam and water to the metal surface inside the tube, ζ is the correction coefficient related to the uniformity of the flue gas washing the heating surface;ɑ d is the convective heat release coefficient of the flue gas to the tube wall surface of the heating surface,ɑ f is the radiation heat release coefficient of the flue gas to the tube wall of the heating surface; When the solid fuel is combusted, the tube bundles are arranged in staggered arrangement, the transition zone of economizer and once-through boiler, the evaporation heating surface and the heating surface of supercritical pressure boiler are taken as the convection heating surface, for the pollution factor of the half radiation and half convection heating surface, a calculation method is that, wherein a1= ζ(α d + a f ), ψ is the thermal effective coefficient, which is related to the actual heat transfer coefficient of the heating surface and the clean heat transfer coefficient; K sj is the actual heat transfer coefficient of the heating surface, α1 is the heat release coefficient of the ash-free flue gas flow on the clean tube wall, Q sj is the heat absorbed by the steam and water, B j is the calculated fuel quantity of the boiler, A is the heat transfer area of the heating surface, Δt is the heat transfer temperature difference of the heating surface, α2 is the heat release coefficient of the steam and water to the metal surface inside the tube, ζ is the correction coefficient related to the uniformity of the flue gas scouring the heating surface; ɑ d is the convective heat release coefficient of the flue gas to the tube wall surface of the heating surface, α f is the radiative heat release coefficient of the flue gas to the tube wall of the heating surface.

5. The method of claim 2, wherein, For the pollution factor of the half radiation and half convection heating surface, A calculation method is that, wherein K sj K is the actual heat transfer coefficient of the heating surface qj Q is the heat transfer coefficient of the heating surface corresponding to the clean state sj B is the actual heat absorbed by the heating surface j H is the heat transfer area of the heating surface, and Δt is the temperature difference of the heating surface fqj Q is the radiation heat absorbed by the heating surface corresponding to the clean state dqj Q is the convective heat absorbed by the heating surface corresponding to the clean state D is the steam-water flow rate corresponding to the clean state of the heating surface, i" and i' are the outlet enthalpy and inlet enthalpy of the steam-water corresponding to the clean state of the heating surface, respectively, α1 is the heat release coefficient of the ash-free flue gas flow on the clean tube wall, and α2 is the heat release coefficient of the steam-water on the inner metal surface of the tube; A calculation method is that, Wherein, D is the steam-water flow through the heating surface, Δh sj is the actual enthalpy rise of steam-water between the outlet and inlet of the heating surface, H is the heat transfer area of the heating surface, ΔT sj is the actual temperature and pressure of the heating surface, β j is the calculated fuel quantity of the boiler, Δh qj is the enthalpy rise of the heating surface corresponding to the clean state, Q fqj is the radiation absorption heat of the heating surface corresponding to the clean state, α1 is the heat release coefficient of the ash-free flue gas flow on the clean tube wall, and α2 is the heat release coefficient of the steam-water to the metal surface in the tube. A calculation method is that, wherein, is the heat retention coefficient, ΔH sj is the actual enthalpy drop of the flue gas between the inlet and outlet of the heated surface, Q fsj is the actual radiation heat absorbed by the heated surface, H is the heat transfer area of the heated surface, ΔT sj is the actual heat transfer temperature and pressure of the heated surface, α1 is the heat release coefficient of the flue gas side ash-free gas flow against the clean tube wall, α2 is the heat release coefficient of the steam and water against the metal surface in the tube, Q fqj is the radiation heat absorbed by the heated surface corresponding to the clean state, ΔH qj is the enthalpy drop of the flue gas in the clean state between the inlet and outlet of the heated surface; A calculation method is that, Wherein, K sj K is the actual heat transfer coefficient of the heated surface, ε is the ash fouling coefficient, caused by the ash in the flue gas and the thermal resistance caused by the ash fouling layer of the heated surface; Q fsj Q is the actual radiation heat absorption of the heated surface, Q dsj Q is the actual absorption of the flue gas convection heat release of the heated surface, Q sj Q is the actual absorption of the flue gas convection heat release of the heated surface, H is the heat transfer area of the heated surface, ΔT sj K is the actual heat transfer coefficient of the heated surface, ε is the ash fouling coefficient, caused by the ash in the flue gas and the thermal resistance caused by the ash fouling layer of the heated surface; Q fsj Q is the actual radiation heat absorption of the heated surface, Q dsj Q is the actual absorption of the flue gas convection heat release of the heated surface, Q sj Q is the actual absorption of the flue gas convection heat release of the heated surface, H is the heat transfer area of the heated surface, ΔT sj K is the actual heat transfer coefficient of the heated surface, ε is the ash fouling coefficient, caused by the ash in the flue gas and the thermal resistance caused by the ash fouling layer of the heated surface; Q fsj Q is the actual radiation heat absorption of the heated surface A calculation method is that, B j Q = Qf + Qb fsj D = Df + Db H = Hf + Hb α1 = α1f + α1b α2 = α2f + α2b A calculation method is that, Wherein, φ is the heat preservation coefficient of the section where the heating surface is located, ΔH is the actual enthalpy drop of the flue gas between the inlet and outlet of the heating surface, Q fsj is the actual radiation heat absorption of the heating surface, H is the heat transfer area of the heating surface, ΔT is the heat transfer temperature difference of the heating surface, α1 is the heat release coefficient of the clean tube wall washed by the flue gas without ash on the flue gas side, and α2 is the heat release coefficient of the metal surface inside the tube washed by the steam and water. For the pollution factor calculation formula of the above half radiation and half convection heating surface, the calculation method of the radiation heat absorption is that, For the pollution factor of the full radiation heating surface, a calculation method is that, wherein, a d is the convective heat transfer coefficient of the flue gas side, s pz is the longitudinal pitch of the panel or tube heating surface, x p is the angular coefficient of the panel or tube heating surface, d is the outer diameter of the heating surface tube, a f is the radiative heat transfer coefficient of the flue gas to the tube wall, and ζ is the utilization coefficient, which is a coefficient that takes into account the reduction in heat due to incomplete washing of the panel. For the pollution factor of the air preheater taken as the convection heating surface, whether it is the tube type air preheater or for the rotary type air preheater, a calculation method is that, a1= ζ(α d + a f ), wherein, α1 is the heat release coefficient of the flue gas side without ash flow scouring the dirty pipe wall, ɑ d is the heat release coefficient of the flue gas against the pipe wall surface, α f is the radiation heat release coefficient of the flue gas against the pipe wall; For the tube type air preheater, the pollution factor is that, Qabs is the absorbed radiation heat in the first semi-radiation semi-convection heating surface in the corresponding clean state fqj Qabs is the absorbed radiation heat in the first semi-radiation semi-convection heating surface in the corresponding clean state wherein Q' flqj Q" is the heat absorbed by the first semi-radiation heating surface at the entrance of the first semi-radiation heating surface adjacent to the furnace outlet in the clean state f1qj η is the heat radiated from the furnace and the first semi-radiation heating surface to the second heating surface behind the flue gas flow in the clean state g β is the correction coefficient considering the mutual radiation influence of the furnace and the first semi-radiation heating surface; q H is the average heat load of the furnace radiation heating surface A is the heat absorbed by 1 kg of fuel in the effective radiation heating surface of the furnace lf B is the total effective radiation heating area of the furnace j F" is the calculated fuel quantity of the boiler l a1 is the blackness of the flue gas between the first semi-radiation heating surface; x" gr1 is the angular coefficient of the entrance cross section to the exit cross section of the first semi-radiation heating surface; F" gr1 T is the flue gas exit area of the first semi-radiation heating surface gr1 T is the average temperature of the flue gas between the first semi-radiation heating surface; ζ r is the correction coefficient considering the fuel type, ζ r = 0.5; Q - actual radiation heat of the first semi-radiation semi-convection heating surface at the furnace outlet fsj Q - radiation heat absorbed by the surface in the corresponding clean state fqj is calculated in the same way, but using the parameters in the actual state. Qabsorbedradiationheatbythesecondheatsurfacebehindthefirsthalfradiantheatsurfaceattheoutletofthefurnacefortheflowoffluegasesforthe f2qj Qabsorbedradiationheatbythesecondheatsurfacebehindthefirsthalfradiantheatsurfaceattheoutletofthefurnacefortheflowoffluegasesforthe wherein Q" f1qj Q" is the heat radiated from the first semi-radiation heating surface and the hearth to the second heating surface behind the flue gas flow in the clean state f2qj β2 is the correction coefficient considering the mutual radiation influence of the first semi-radiation heating surface and the second heating surface behind the flue gas flow; a2 is the flue gas blackness between the second heating surface; x" gr2 is the angular coefficient of the second heating surface inlet cross section to the outlet cross section; F" gr2 is the flue gas outlet area of the second heating surface, T gr2 is the average temperature of the flue gas between the second heating surface, ζ r2 is the correction coefficient considering the fuel type, B j boiler calculation fuel quantity; For the second heating surface behind the first semi-radiation heating surface flue gas flow at the furnace outlet, the actual absorbed radiation heat Q f2sj The calculation method is the same as that of the absorbed radiation heat Q f2qj in the clean state, and is calculated according to the parameters in the actual state.

6. The method of claim 2, wherein, A calculation method is that, wherein, D = Evaporation of total radiation heating surface, Δh = Steam enthalpy rise between outlet and inlet of total radiation heating surface, A p Effective radiation area of total radiation heating surface, ζ p Contamination absorption coefficient of total radiation heating surface; η i Distribution coefficient of radiation heat absorption of total radiation heating surface; Effective radiation heat intensity of total radiation heating surface, q H Average heat load of furnace radiation heating surface, Heat absorption of 1 Kg of fuel by effective radiation heating surface of furnace, A lf Total effective radiation heating area of furnace, B j Calculated fuel quantity of boiler 7. The method of claim 2, wherein, A calculation method is that, wherein respectively, actual reduced pressure difference of air preheater, reduced pressure difference in clean state, O 2，xgy sj , O 2，0gy sj respectively, oxygen content in dry flue gas in actual working condition and actual reduced working condition, MW x sj , MW0 sj respectively, generator power in actual working condition and actual reduced working condition, O 2，xgy qj , O 2，0gy qj respectively, oxygen content in dry flue gas in clean working condition and clean reduced working condition, actual reduced working condition is working condition of rated power and certain oxygen content in dry flue gas in actual pollution state; MW x qj , MW0 qj respectively, generator power in clean working condition and clean reduced working condition, clean reduced working condition is working condition of rated power and certain oxygen content in dry flue gas in clean working condition; For the pollution factor of the rotary type air preheater, a calculation method is that, A calculation method is that, K skj , K qjk Q d is the heat absorbed by the air in the air preheater, A is the heat exchange outer surface area of the air preheater, Δt is the air preheater temperature pressure, α1, α2 are the flue gas heat release coefficient and air heat release coefficient of the air preheater respectively, B j is the calculated fuel quantity of the boiler; A calculation method is that, wherein, K sjk For the actual heat exchange coefficient of the air preheater, α1 and α2 are the flue gas heat release coefficient and the air heat release coefficient of the heating surface of the air preheater respectively, and ζ is the utilization coefficient, representing the comprehensive influence coefficient of the ash fouling and incomplete flushing of the heating surface of the air preheater. Wherein, In the above air preheater pollution factor calculation formula, whether it is the tube type air preheater or the rotary type air preheater, the actual heat exchange coefficient is that, wherein, K sjk C is the non-steady heat transfer influence coefficient caused by the change of rotating speed; x y , x k are the proportions of flue gas and air to wash the rotor respectively; α1 and α2 are the flue gas heat release coefficient and air heat release coefficient of the heating surface of the air preheater respectively, and ζ is the utilization coefficient, representing the comprehensive influence coefficient of the ash fouling and incomplete washing of the heating surface of the air preheater. The method for establishing the soot blowing economic model is that: combined with the soot blowing field test of the boiler steam, according to the quantitative influence data of the soot blowing action on the main steam temperature, the reheat steam temperature and the exhaust gas temperature under different working conditions measured by the control variable method, the comprehensive influence on the boiler efficiency is represented as the basis for the evaluation of the system economy; at the same time, the soot blowing consumption and the soot blowing benefit are comprehensively considered, which specifically includes: (1) according to the field experiment, the influence model of each group of soot blower action on the boiler efficiency under different loads is established, including the action benefit of each group of soot blower = the heat exchange capacity improved after the action of each group of soot blower, that is, the increase of the boiler efficiency and the benefit; K sjk , K qjk are the heat transfer coefficients of the air preheater in actual and clean state respectively, C is the unsteady heat transfer coefficient caused by the change of rotation speed; x y , x k are the proportions of flue gas and air to wash the rotor respectively; α1, α2 are the flue gas heat release coefficients and air heat release coefficients of the heating surface of the air preheater respectively; (2) according to the operating parameters, the operating consumption cost model of each group of soot blower is established, including the operating consumption cost of each group of soot blower = the steam consumption of each soot blower each time × the total input of each group of soot blower within a certain time × the cost of unit steam consumption and power consumption; wherein, β" ky Excess air ratio of air preheater outlet air; Δα ky Air leakage factor of air preheater air leakage to flue gas; Theoretical air enthalpy on air preheater air outlet and inlet cross section respectively, B j Boiler calculated fuel quantity, Δt is logarithmic mean temperature and pressure, Δt d Medium temperature difference of the end of air preheater heating surface with larger temperature difference, Δt x Medium temperature difference of the end of air preheater heating surface with smaller temperature difference, A is air preheater heat transfer area.

8. The method of claim 1, wherein, (3) the soot blowing economic model of each group of soot blower is established to realize the economic optimization of soot blowing operation, including the comprehensive economic benefit = the benefit increase brought by the soot blowing of each group of soot blower - operating consumption cost + the steam consumption and power consumption cost saved by reducing the soot blowing frequency + the labor operation cost and equipment maintenance cost saved by reducing + the safety benefit brought by reducing the boiler heating surface blowdown + the environmental protection benefit brought by reducing the exhaust gas emission, which is maximized under the premise of ensuring the safety of the operating parameters; The method for establishing the soot blowing safety model is that: ​ ​ ​ 1) Set the frequency of each ash cleaning device per day cannot be higher than the upper limit, including each ash cleaning device per day no more than three times; 2) Set the frequency of each ash cleaning device within a certain time cannot be lower than the lower limit, including each ash cleaning device per week no less than five times; 3) Ensure that the main steam temperature and the reheat steam temperature are not overheated or underheated as an important condition for intelligent ash cleaning, including setting the main steam temperature not higher than the design temperature by 3℃, and not lower than the design temperature by 5℃; setting the reheat steam temperature not higher than the design temperature by 3℃, and not lower than the design temperature by 4℃; 4) Set the low load limit for not cleaning, including setting not to clean below 30% rated load or 25% rated load; 5) Set the ash cleaning device action and state signal into DCS, when the signal is not normal, immediately exit the ash cleaning device; Comprehensive boiler ash cleaning economic model, ash cleaning safety model, establish ash cleaning comprehensive evaluation model, through real-time acquisition of boiler operation parameters, set the ash cleaning safety limit condition, suspend or stop ash cleaning in time; Comprehensive ash cleaning steam consumption, power consumption, ash cleaning income, steam temperature, exhaust gas temperature, frequency, etc. Evaluate the economy.

9. The method of claim 1, wherein, The method for formulating the closed-loop control model is: formulating the control logic in the intelligent server or DCS system, respectively, comprehensively monitoring the data of the boiler heating surface and water wall overall, single side and local area pollution state, ash cleaning comprehensive evaluation information and safety information, and incorporating into the control program; That is, the formulated closed-loop control model includes: the furnace water wall overall, single side and local area, convection heating surface, full-radiation heating surface, half-radiation half-convection heating surface and air preheater, and the heating surface pollution factor division, combination model and ash cleaning device arrangement and grouping situation, and the ash cleaning safety limit, economy and comprehensive judgment are incorporated into the control program; The formulated control program can realize the optimization control of the ash cleaning device according to the modeling grouping of the heating surface and the independent operation of the single ash cleaning device, realize the control of the boiler heating surface, different sides, water wall overall, single side and local area respectively, realize the on-demand, economic and safe ash cleaning; At the same time, the control logic of the existing ash cleaning device is retained, and the interlocking and switching conditions of the closed-loop control model and the existing ash cleaning device control logic and the intelligent ash cleaning start button are set to ensure the normal and safe switching and operation of the two ash cleaning methods; The monitoring picture is made in the intelligent server or DCS system, the accurate monitoring and closed-loop control of the pollution state of the whole, single side and local area of the boiler heating surface and water cooling wall are realized, and the interaction with the operator is realized. The main monitoring information and control method of the monitoring picture mainly include: the number of ash removal device, the operation of ash removal device, the state of ash removal device and corresponding area pollution factor, the button of steam trap and the state of steam trap, the button and state of main steam valve, the button and state of auxiliary steam valve, the button and state of intelligent ash removal, the pollution factor of each heating surface, the inlet and outlet flue gas temperature, the load, the main steam flow, the reheat steam flow, the temperature, the time, the number of furnace endoscope monitoring device, the number of inner wall temperature measuring device or wall temperature measuring point, and the number of inner wall temperature measuring device or wall temperature measuring point. When the mouse clicks the left button at the button, the operation of the corresponding button can be performed, and when the mouse clicks the right button at the button or symbol, the state and parameter of the corresponding button or symbol can be displayed.

10. A system for intelligent monitoring, supervising and closed-loop control of the fouling of heating surfaces in a utility boiler, implementing the method of claim 1, comprising: The inner wall temperature measuring device or wall temperature measuring point, the furnace inner peep monitoring device, the data collector, the compensation lead, the communication cable, the switch, the optical fiber or the communication cable, the intelligent server, the DCS system, the DCS data interface card and the communication protocol are characterized in that the inner wall temperature measuring device or wall temperature measuring point is arranged on the furnace water cooling wall, the furnace inner peep monitoring device is arranged, the tube wall temperature measuring point and the fin wall temperature measuring point in the inner wall temperature measuring device or wall temperature measuring point are connected with the data collector through the compensation lead, a plurality of data collectors are connected with the switch in sequence through the communication cable, the data measured by the tube wall temperature measuring point and the fin wall temperature measuring point in the inner wall temperature measuring device or wall temperature measuring point are sent into the switch through the data collector, the furnace inner peep monitoring device is connected with the switch through the twisted pair or the communication cable, the video data are sent into the switch, the switch is connected with the DCS system through the optical fiber or the communication cable, the data of the newly added measuring point are sent into the DCS system, the data measured by the measuring point equipment arranged in the boiler heating surface region according to the need, the intelligent server and the DCS system are connected with the communication cable, the data are read and written in the OPC communication protocol mode, or the data are read and written in the modbus communication protocol through the communication cable and the DCS data interface card, the software model is established in the intelligent server, including the pollution factor calculation model, the ash removal economic model, the ash removal safety model, the ash removal comprehensive evaluation model established according to the method provided in the application, and the data reading module, the data preprocessing module and the intelligent ash removal database, the closed loop control model and the monitoring and control picture are arranged in the intelligent server or the DCS system; the intelligent server reads the data from the DCS system through the data reading module, the data are sent into the intelligent ash removal database, the ash removal safety model and the ash removal economic model after being processed by the data preprocessing module; the pollution factor calculation model obtains the data from the intelligent ash removal database, and sends the calculated pollution factor data into the closed loop control model and returns to the intelligent ash removal database; the ash removal safety model and the ash removal economic model send the operation results into the ash removal comprehensive evaluation model for comprehensive evaluation, and send the comprehensive evaluation information into the closed loop control model, the closed loop control model realizes the operation optimization control of the ash removal device after processing the pollution factor data and the comprehensive evaluation information; the monitoring and control picture reads the pollution factor data from the intelligent ash removal database and obtains the related parameters and equipment state information from the DCS system, and performs monitoring and control.

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