CN105091932B - A kind of three points of storehouses rotary preheater segmentation dust stratification monitoring method - Google Patents

Abstract

The invention discloses a segmented ash accumulation monitoring method for a three-segment rotary preheater, which mainly includes a data acquisition module, a calculation module and an output module. The data acquisition module collects coal quality parameters, structural parameters and real-time boiler operating parameters , the segmental cleaning factor is calculated by the established preheater dust accumulation monitoring model, and finally the output module outputs the segmental real-time cleaning factor of the preheater in the form of a real-time parameter curve. Aiming at the shortcomings and deficiencies of the overall ash accumulation monitoring method of the existing power plant preheater, the present invention proposes the idea of segmental ash accumulation monitoring, and establishes a segmental ash accumulation monitoring calculation model, which can provide visual data on the ash accumulation of the preheater, and can It helps operators to judge the proper timing of soot blowing and carry out segmental soot blowing, thereby reducing the steam loss of the soot blower and improving the heat transfer efficiency of the preheater.

Description

A monitoring method for segmental dust deposition in a three-segment rotary preheater

technical field

The invention belongs to the technical field of boiler dust accumulation monitoring, in particular to a segmental dust accumulation monitoring method for a rotary preheater with three compartments.

Background technique

At present, coal-fired boilers in large-scale power stations mostly use three-chamber rotary preheaters to recover flue gas heat to preheat air, thereby enhancing combustion, reducing exhaust gas temperature and improving boiler efficiency. The heat transfer element of the three-chamber rotary preheater is composed of closely arranged heat storage plates. Due to its compact structure and narrow working medium passage, it is easy to accumulate dust and even block the working medium passage, resulting in increased smoke air flow resistance. The heat transfer efficiency is reduced, which affects the normal operation of the preheater, so it must be cleaned frequently by soot blowing.

The heat transfer elements of the three-chamber rotary preheater are divided into hot section (including hot section layer 1 and hot section middle layer 2) and cold section (including cold section layer 3) according to different materials. In comparison, elements in the cold section are more likely to accumulate dust than elements in the hot section. Nowadays, in order to enhance the soot blowing effect, power plants have arranged steam soot blowers at the hot and cold ends (upper and lower ends) (as shown in Figure 2). The hot section soot blower 4 and the cold end soot blower 5 at the lower end can blow soot in sections. However, power plant operators usually judge the soot accumulation degree of the preheater according to the pressure difference between the inlet and outlet of the flue gas. This method can only roughly judge the overall ash accumulation situation of the preheater, and cannot carry out segmental monitoring, so only experience will lead to soot blowing Frequent steam loss is too large, or the soot blowing is not timely and the heat transfer efficiency of the preheater is reduced. Therefore, it is very important to establish a monitoring model for segmental ash deposition in the preheater that meets the requirements.

Contents of the invention

Aiming at the deficiencies of the existing technology, the present invention provides a three-chamber rotary preheater segmented ash accumulation monitoring method: providing intuitive data of the segmental ash accumulation degree of the preheater to help operators judge the appropriateness of the hot and cold sections Soot blowing is performed in stages, so as to reduce the steam loss of the soot blower and improve the heat transfer efficiency of the preheater.

The present invention adopts following technical scheme:

The invention discloses a segmented ash deposition monitoring method for a rotary preheater with three compartments. The method of the invention is divided into three modules: a data acquisition module, a calculation module and an output module. Among them, the data acquisition module mainly collects the coal quality data of the furnace, the structural parameters of the preheater and the real-time operation data of the preheater. The calculation module defines the utilization coefficient that can characterize the cleanliness of the preheater as the cleaning factor, and performs thermal calculation on the preheater according to the collected data to obtain the segmental cleaning factor. Finally, the output module makes a graph of the cleaning factor according to the time distribution and presents it to the operator, so as to provide a basis for segmental soot blowing.

The data acquisition module includes the acquisition of furnace coal quality data, structural parameters of the preheater and real-time operation data of the preheater. Among them, the data of coal quality into the furnace is obtained through coal quality analysis. If the coal sample to be burned is blended coal, the proportion of different coal samples is also required. The structural parameters of the preheater are obtained from the product manual of the preheater, which requires the material of the heat storage plate, the quality of the heat storage plate, the length of the heat storage plate (flattened), the heating area of the heat storage plate, the flue gas circulation area, the primary air flow area, and the secondary air flow. Air circulation area, ratio of hot and cold sections, smoke and air circulation area to total circulation area. The real-time operation data is collected through the DCS system of the power plant. The main measurement points include: preheater rotor speed, boiler coal consumption, boiler efficiency, flue gas inlet and outlet temperature, primary air inlet and outlet temperature, secondary air inlet and outlet temperature, primary air inlet Flow and secondary air inlet and outlet flow (the above measuring points are indispensable, if the power plant lacks, the measuring points should be added).

The calculation module defines the utilization coefficient of the preheater as the cleaning factor. The larger the utilization coefficient is, the cleaner the preheater is, and the smaller the utilization coefficient is, the more dust is accumulated in the preheater and soot blowing is required. Therefore, the utilization coefficient of the preheater, which is defined as the cleaning factor, indirectly characterizes the degree of ash accumulation, and the utilization coefficients of the hot and cold sections need to be calculated for segmental ash accumulation monitoring. The calculation process is as follows:

Calculation assumptions:

(a) The heat transfer calculation of the three-chamber rotary preheater adopts the convective heat transfer model, that is, all the flue gas transfers heat to the air in the form of convective heat transfer, and the flue gas and air flow in a countercurrent direction;

(b) For the primary and secondary air ducts on the air side, the air flow share calculated in the hot and cold sections is the same as that in the overall calculation;

(c) All the air leaked into the flue gas side comes from the primary and secondary air ducts. The air leakage coefficients of heat, cold and section are different, and the details are determined by the heat balance;

calculation steps

Step 1: According to the overall heat balance of the preheater, calculate the average excess air coefficient on the air side and the total air leakage coefficient on the flue gas side:

(1) Heat release on the flue gas side:

(2) primary air heat absorption:

Secondary air heat absorption:

Total air heat absorption: in

g ₂ =1-g ₁

(3) Calculate the average excess air coefficient on the air side according to the measured average flow rate of the secondary air of the preheater:

in

(4) Calculate the total air leakage coefficient Δα on the flue gas side by combining the formulas (1) and (2) in this step according to the heat balance Q _y =Q _k ;

Among them, Q _y is the overall flue gas heat release; Q _k is the overall air heat absorption; Q _k1 is the overall primary air heat absorption; Q _k2 is the overall secondary air heat absorption; I _y ′, I _y ″ are respectively Flue gas inlet and outlet enthalpy; I _k1 ′, I _k1 ″ are air enthalpy at primary air inlet and outlet respectively; I _k2 ′, I _k2 ″ are secondary air inlet and outlet air enthalpy respectively; is the average enthalpy of the air side inlet and outlet (weighted by the primary and secondary air duct); D ₁ ′ is the primary air inlet flow; D ₂ ′, D ₂ ″ is the secondary air inlet and outlet flow; V ⁰ is the theoretical air volume ; is the heat retention coefficient of the boiler, which is taken as 0.998; g ₁ and g ₂ are the proportions of the primary and secondary air flow in the total air flow; is the average excess coefficient of the air side; Δα is the air leakage coefficient from the air side to the flue gas side; ρ _k is the air density; B _j is the calculated coal combustion amount.

Step 2: Assuming the outlet smoke temperature θ _m of the hot section (that is, the inlet smoke temperature of the cold section), list the heat balance equations of the hot section and the cold section, and calculate the air leakage coefficients Δα _h , Δα _c of the hot section and the cold section, and the average inlet air of the hot section Temperature t _k,m (i.e. the average temperature of the air at the outlet of the cold section):

(1) Establish the heat balance equation of the hot section:

(2) Establish the heat balance equation of the cold section:

(3) According to the flue gas enthalpy temperature table, calculate I _{y,m by interpolation method from the hypothetical value θ m ;}

(4) Combining (1) and (2) in this step and the condition Δα _h + Δα _c = Δα, calculate the hot and cold section air leakage coefficient Δα _h , Δα _c and the average enthalpy of the hot section inlet air (average enthalpy of air at the outlet of the cold section);

(5) According to the air enthalpy temperature table, by Use the interpolation method to obtain t _k,m ; (the flue gas and air enthalpy temperature tables are obtained through coal quality analysis, which is the common sense of thermal calculation and will not be repeated)

Among them, θ _m is the flue gas temperature at the outlet of the hot section (i.e. the temperature at the inlet of the cold section); I _{y,m is} the enthalpy of the flue gas at the outlet of the hot section (i.e. the enthalpy of the flue gas at the inlet of the cold section); Temperature (that is, the average temperature of the air at the outlet of the cold section); The average enthalpy of the air at the inlet of the hot section (that is, the average enthalpy of the air at the outlet of the cold section); Δα _h and Δα _c are the side-to-flue air leakage coefficients of the air at the hot and cold sections, respectively.

Step 3: Assuming that the primary air temperature at the inlet of the hot section is t _k1,m (that is, the primary air temperature at the outlet of the cold section), calculate the heat release coefficients of the flue gas, primary air and secondary air on the heat storage plate in the hot and cold sections respectively, and then calculate Heating surface utilization coefficient of hot and cold sections:

(1) Assuming the primary air temperature t _k1,m at the inlet of the hot section, calculate the secondary air temperature t _k2,m at the inlet of the hot section according to t _k,m = g ₁ t _k1,m + g ₂ t _k2 ,m;

(2) Average temperature of flue gas in hot and cold sections:

Average temperature of primary air in hot and cold sections:

Average temperature of secondary air in hot and cold sections:

(3) Average temperature difference in the hot section:

Average temperature difference of cold section:

(1) Heat transfer coefficient of hot section:

Cold section heat transfer coefficient:

(2) Flue velocity in the hot section:

Cold section flue gas flow rate:

Primary air velocity in hot section:

Primary air velocity in cold section:

Hot section secondary air velocity:

Secondary air velocity in cold section: (in )

(3) Convective heat release coefficient on the flue gas side of the hot section:

Convective heat release coefficient of flue gas side in cold section:

Convective heat release coefficient of the primary air side in the hot section:

The convective heat release coefficient of the primary air side of the cold section:

Convective heat release coefficient on the secondary air side of the hot section:

Convective heat release coefficient of the secondary air side in the cold section:

(in );

(4) Utilization coefficient of hot section:

Cold section utilization factor:

Among them, (h) and (c) represent the hot section and the cold section respectively; the subscripts y and _k represent flue gas and air respectively; t″ _k1 respectively represent the inlet and outlet temperatures of the overall primary air of the preheater; t′ _k2 and t″ _k2 are the inlet and outlet temperatures of the overall secondary air of the preheater respectively; is the average temperature of flue gas; _ΔT is the logarithmic average temperature difference; K is the heat transfer coefficient; _w is the flow velocity; _Q is the heat release; Secondary air circulation cross-sectional area; V _y is actual flue gas volume; α is convective heat release coefficient; d _eq is equivalent diameter of heat storage plate; Re is Reynolds number; Pr is Prandtl number; kinematic viscosity; Z is the heat storage plate type coefficient; C _t and C _l are the correction coefficients involved in the calculation, which can be taken as 1 for the heat transfer of the preheater; H is the heating area; x _y , x _k1 , x _k2 are respectively is the proportion of the heating surface area of the flue gas, primary air and secondary air channels to the total heating area; ξ is the utilization coefficient that can characterize the cleanliness of the heating surface.

Step 4: According to the surface heat transfer equations of the flue gas, primary air and secondary air in the hot section and the heat storage plate, respectively calculate the wall temperature of the heat storage plate on the interface of the flue gas channel in the hot section (heat transfer equation and air duct layout of the preheater Relevant, the rotation direction of the air preheater here is according to the flue gas to the secondary air, then to the primary air, and finally back to the flue gas), list the calibration conditions of the hot section, and check the inlet primary air temperature t _k1,m of the hot section assuming value:

(1) Establish the heat transfer equation between the flue gas in the hot section and the surface of the heat storage plate:

Establish the heat transfer equation between the secondary air in the hot section and the surface of the heat storage plate:

Establish the heat transfer equation between the primary air in the hot section and the surface of the heat storage plate:

(2) By t″ _{w, y} (h)=t′ _{w, k2} (h), t″ _{w, k2} (h)=t′ _{w, k1} (h), t″ _{w, k1} (h)=t ′ _{w, y} (h) boundary conditions, parallel

The three equations in (1) calculate the heat storage plate wall temperature t′ _w,y (h) and t′ _w ′ _,y (h) on the interface of the overall flue gas channel of the preheater, that is, the tangential direction of the rotor in the flue gas area of the hot section (rotation direction) average wall temperature of the heat storage plate at the inlet and outlet;

(3) Checking conditions: the heat release of the flue gas in the hot section of the air preheater is equal to the heating amount of the flue gas in the flue gas area to the heat storage plate, and the error is ±2%; that is

Check the assumed primary air temperature t _k1,m at the inlet of the hot section according to the above conditions (that is, the primary air temperature at the outlet of the cold section). If the conditions are met, the assumption is correct, and then proceed to step 5; if the conditions are not met, the assumption is wrong, and repeat steps 3 to 4;

Among them, t′ _w,y (h) and t″ _w,y (h) are the average wall temperature of the heat storage plate at the inlet and outlet of the rotor tangential (rotation direction) in the flue gas area of the hot section respectively; t′ _w,k2 (h ), t″ _w,k2 (h) are the average wall temperature of the heat storage plate at the inlet and outlet of the rotor tangential (rotation direction) in the secondary air area of the hot section; t′ _w,k1 (h), t″ _w,k1 ( h) are the average wall temperature of the heat storage plate at the inlet and outlet of the rotor tangential (rotation direction) in the primary air area of the hot section; G(h) is the total mass of the heat transfer elements of the heat storage plate in the hot section; n is the rotor speed; c _{x, h} is the specific heat capacity of the heat storage plate material in the hot section;

Step 5: According to the surface heat transfer equations of the flue gas, primary air and secondary air in the cold section and the heat storage plate, respectively calculate the wall temperature of the heat storage plate on the interface of the flue gas channel in the cold section, list the calibration conditions of the cold section, and check Assumed value of smoke temperature θ _m at the outlet of the hot section (smoke temperature at the inlet of the cold section), output the utilization coefficient value of the hot section and the cold section:

(1) The heat transfer equation between the flue gas in the cold section and the surface of the heat storage plate:

The heat transfer equation between the secondary air in the cold section and the surface of the heat storage plate:

The heat transfer equation between the primary air in the cold section and the surface of the heat storage plate:

(2) by t " _{w, y} (c) = t ' _{w, k2} (c), t " _{w, k2} (c) = t ' _{w, k1} (c), t " _{w, k1} (c) = t ′ _w,y (c) boundary conditions, and in parallel with the three equations in (1) of this step to calculate the heat storage plate wall temperature t′ _w,y (c), t″ _w on the interface of the overall flue gas channel of the preheater _{, y} (c), is the average wall temperature of the heat storage plate at the tangential (rotation direction) inlet and outlet of the rotor in the flue gas area of the cold section;

(3) Checking conditions: the heat release of the flue gas in the cold section of the air preheater is equal to the heating amount of the flue gas in the flue gas area to the heat storage plate, and the error is ±2%; that is

Check the hypothetical smoke temperature θ _m at the outlet of the hot section (smoke temperature at the inlet of the cold section) according to the above conditions, and if the conditions are met, output the utilization coefficients of the hot and cold sections calculated in step 3 as the cleaning factor; if the middle conditions cannot be met, then If wrong, repeat steps 2 to 5;

Among them, t′ _w,y (c) and t″ _w,y (c) are respectively the average wall temperature of the heat storage plate at the inlet and outlet of the rotor tangential (rotation direction) in the flue gas area of the cold section; t′ _w,k2 (c ), t″ _{w, k2} (c) are the average wall temperature of the heat storage plate at the tangential (rotating direction) inlet and outlet of the rotor in the secondary air area of the cold section, respectively; t′ _{w, k1} (c), t″ _{w, k1} (c) are the average wall temperature of the heat storage plate at the inlet and outlet of the rotor tangential (rotation direction) in the primary air area of the cold section; G(c) is the total mass of the heat transfer elements of the heat storage plate in the cold section; c _{x, c} are the cold section The specific heat capacity of the material of the heat storage plate; except for the coal quality parameters and structural parameters of the furnace, other parameters involved in the above calculation process are all real-time parameters collected in the DCS, and the output cleaning factors of the hot section and cold section of the preheater (Utilization factor) is also a real-time value.

The output module makes a real-time parameter graph of the real-time cleaning factors (utilization coefficients) of the hot section and the cold section according to the time distribution (the abscissa is the time axis, and the interval is the DCS collection time interval; the ordinate is the utilization coefficient), which is used as a preheater Based on the visual data of segmental soot monitoring, the operator can judge the timing of soot blowing according to the real-time parameter curves of the hot and cold segments, and control the soot blowers at the hot and cold ends to perform segmental soot blowing.

Description of drawings

Fig. 1 is a flowchart of the present invention;

Figure 2 is a cross-sectional view of the heat transfer element of the preheater and the distribution of the hot and cold end sootblowers;

Fig. 3 is a flow chart of segmental cleaning factor calculation by the calculation module according to the preheater dust accumulation monitoring model.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings.

The technical solutions in the embodiments of the present invention will be clearly and completely described and discussed below in conjunction with the accompanying drawings of the present invention. Obviously, what is described here is only a part of the examples of the present invention, not all examples. Based on the present invention All other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

As shown in Fig. 1 to Fig. 3, a three-chamber rotary preheater segmented dust accumulation monitoring method, a data acquisition module, a calculation module and an output module. The data acquisition module is realized by directly collecting data in the power plant, and the output of the measuring points of the DCS or SIS system of the power plant is usually in the form of Excel table data, which is easier to collect under the premise of clear measuring points; the calculation module involves many parameters and the process requires It can be realized through Matlab programming; the output module needs to present real-time parameter graphs, or the output values can be formed into graphs through Matlab programming. (Computer programming can also choose other software)

The data acquisition module includes the acquisition of furnace coal quality data, structural parameters of the preheater and real-time operation data of the preheater. Among them, the data of coal quality into the furnace is obtained through coal quality analysis. If the coal sample to be burned is blended coal, the proportion of different coal samples is also required. The structural parameters of the preheater are obtained from the product manual of the preheater, which requires the material of the heat storage plate, the quality of the heat storage plate, the length of the heat storage plate (flattened), the heating area of the heat storage plate, the flue gas circulation area, the primary air flow area, and the secondary air flow. Air circulation area, ratio of hot and cold sections, smoke and air circulation area to total circulation area. The real-time operation data is collected through the DCS system of the power plant. The main measurement points include: preheater rotor speed, boiler coal consumption, boiler efficiency, flue gas inlet and outlet temperature, primary air inlet and outlet temperature, secondary air inlet and outlet temperature, primary air inlet Flow and secondary air inlet and outlet flow (the above measuring points are indispensable, if the power plant lacks, the measuring points should be added).

The calculation module defines the utilization coefficient of the preheater as the cleaning factor. The larger the utilization coefficient is, the cleaner the preheater is, and the smaller the utilization coefficient is, the more dust is accumulated in the preheater and soot blowing is required. Therefore, the utilization coefficient of the preheater, which is defined as the cleaning factor, indirectly represents the degree of ash accumulation, and the utilization coefficients of the hot and cold sections need to be calculated for segmental ash accumulation monitoring. The calculation process is realized by Matlab programming. First, the data collected in the data acquisition module is imported (because it is in Excel format, it can be read directly). The specific calculation steps are as follows (see accompanying drawing 3):

Step 1: According to the overall heat balance of the preheater, calculate the average excess air coefficient on the air side and the total air leakage coefficient on the flue gas side:

(1) Heat release on the flue gas side:

(2) primary air heat absorption:

Secondary air heat absorption:

Total air heat absorption: (in g ₂ =1-g ₁ )

(3) Calculate the average excess air coefficient on the air side according to the measured average flow rate of the secondary air of the preheater:

in

(4) Calculate the total air leakage coefficient Δα on the flue gas side by combining the formulas (1) and (2) in this step according to the heat balance Q _y =Q _k ;

Among them, Q _y is the overall flue gas heat release; Q _k is the overall air heat absorption; Q _k1 is the overall primary air heat absorption; Q _k2 is the overall secondary air heat absorption; I _y ′, I _y ″ are respectively Flue gas import and export enthalpy; I _k1 ′, I _k1 ″ are primary air inlet and outlet air enthalpy; I _k2 ′, I _k2 ″ are secondary air inlet and outlet air enthalpy; is the average enthalpy of the air side inlet and outlet (weighted by the primary and secondary air duct); D ₁ ′ is the primary air inlet flow; D ₂ ′, D ₂ ″ are the secondary air inlet and outlet flow; V ⁰ is the theoretical air volume; is the heat retention coefficient of the boiler, which is taken as 0.998; g ₁ and g ₂ are the proportions of the primary and secondary air flow in the total air flow; is the average excess coefficient of the air side; Δα is the air leakage coefficient from the air side to the flue gas side; ρ _k is the air density; B _j is the calculated coal combustion amount.

Step 2: Assuming the outlet smoke temperature θ _m of the hot section (that is, the inlet smoke temperature of the cold section), list the heat balance equations of the hot section and the cold section, and calculate the air leakage coefficients Δα _h , Δα _c of the hot section and the cold section, and the average temperature of the inlet air of the hot section t _k,m (i.e. the average temperature of the air at the outlet of the cold section):

(1) The heat balance equation of the hot section:

(2) The heat balance equation of the cold section:

(3) According to the flue gas enthalpy temperature table, calculate I _{y,m by interpolation method from the hypothetical value θ m ;}

(4) Combining (1) and (2) in this step and the condition Δα _h + Δα _c = Δα, calculate the hot and cold section air leakage coefficient Δα _h , Δα _c and the average enthalpy of the hot section inlet air (average enthalpy of air at the outlet of the cold section);

(5) According to the air enthalpy temperature table, by Use the interpolation method to obtain t _k,m ; (the flue gas and air enthalpy temperature tables are obtained through coal quality analysis, which is the common sense of thermal calculation and will not be repeated)

Among them, θ _m is the flue gas temperature at the outlet of the hot section (i.e. the temperature at the inlet of the cold section); I _{y,m is} the enthalpy of the flue gas at the outlet of the hot section (i.e. the enthalpy of the flue gas at the inlet of the cold section); Temperature (that is, the average temperature of the air at the outlet of the cold section); The average enthalpy of the air at the inlet of the hot section (that is, the average enthalpy of the air at the outlet of the cold section); Δα _h and Δα _c are the side-to-flue air leakage coefficients of the air at the hot and cold sections, respectively.

Step 3: Assuming that the primary air temperature at the inlet of the hot section is t _k1,m (that is, the primary air temperature at the outlet of the cold section), calculate the heat release coefficients of the flue gas, primary air and secondary air on the heat storage plate in the hot and cold sections respectively, and then calculate Heating surface utilization coefficient of hot and cold sections:

(1) Assuming the primary air temperature t _k1,m at the inlet of the hot section, calculate the secondary air temperature t _k2,m at the inlet of the hot section according to t _k,m = g ₁ t _k1,m + g ₂ t _k2 ,m;

(2) Average temperature of flue gas in hot and cold sections:

Average temperature of primary air in hot and cold sections:

Average temperature of secondary air in hot and cold sections:

(3) Average temperature difference in the hot section:

Average temperature difference of cold section:

(5) Heat transfer coefficient of hot section:

Cold section heat transfer coefficient:

(6) Flue velocity in the hot section:

Cold section flue gas flow rate:

Primary air velocity in hot section:

Primary air velocity in cold section:

Hot section secondary air velocity:

Secondary air velocity in cold section: (in )

(7) Convective heat release coefficient on the flue gas side of the hot section:

Convective heat release coefficient of flue gas side in cold section:

Convective heat release coefficient of the primary air side in the hot section:

The convective heat release coefficient of the primary air side of the cold section:

Convective heat release coefficient on the secondary air side of the hot section:

Convective heat release coefficient of the secondary air side in the cold section:

(in );

(8) Utilization coefficient of hot section:

Cold section utilization factor:

Among them, (h) and (c) represent the hot section and the cold section respectively; the subscripts y and _k represent flue gas and air respectively; t″ _k1 respectively represent the inlet and outlet temperatures of the overall primary air of the preheater; t′ _k2 and t″ _k2 are the inlet and outlet temperatures of the overall secondary air of the preheater respectively; is the average temperature of flue gas; ΔT is the logarithmic average temperature difference; K is the heat transfer coefficient; _w is the flow velocity; Q is the heat release, _kJ / _kg ; V _y is the actual flue gas volume; α is the convective heat release coefficient; d _eq is the equivalent diameter of the heat storage plate; Re is the Reynolds number; Pr is the Prandtl number; λ is the heat conduction coefficient; ν is the kinematic viscosity; Z is the heat storage plate type coefficient; C _t and C _l are the correction coefficients involved in the calculation, respectively, which can be taken as 1 for the heat transfer of the preheater; H is the heating area; x _y , x _k1 , x _k2 are the proportions of the heating surface area of the flue gas, primary air and secondary air passages to the total heating area; ξ is the utilization coefficient that can characterize the cleanliness of the heating surface.

Step 4: According to the surface heat transfer equations of the flue gas, primary air and secondary air in the hot section and the heat storage plate, respectively calculate the wall temperature of the heat storage plate on the interface of the flue gas channel in the hot section (heat transfer equation and air duct layout of the preheater Relevant, the rotation direction of the air preheater here is according to the flue gas to the secondary air, then to the primary air, and finally back to the flue gas), list the calibration conditions of the hot section, and check the inlet primary air temperature t _k1,m of the hot section assuming value:

(1) Establish the heat transfer equation between the flue gas in the hot section and the surface of the heat storage plate:

Establish the heat transfer equation between the secondary air in the hot section and the surface of the heat storage plate:

Establish the heat transfer equation between the primary air in the hot section and the surface of the heat storage plate:

(2) By t″ _{w, y} (h)=t′ _{w, k2} (h), t″ _{w, k2} (h)=t′ _{w, k1} (h), t″ _{w, k1} (h)=t ′ _w,y (h) boundary conditions, and the three equations in (1) are used in parallel to calculate the heat storage plate wall temperature t′ _w,y (h), t″ _w,y ( h);

(3) Checking conditions: the heat release of the flue gas in the hot section of the air preheater is equal to the heating amount of the flue gas in the flue gas area to the heat storage plate, and the error is ±2%; that is

Check the assumed primary air temperature t _k1,m at the inlet of the hot section (primary air temperature at the outlet of the cold section) according to the above conditions. If the condition is met, it is assumed to be correct and proceed to step 5; if the condition is not satisfied, the assumption is wrong, and repeat steps 3 to 4;

Among them, t′ _w,y (h) and t″ _w,y (h) are the average wall temperature of the heat storage plate at the tangential (rotating direction) inlet and outlet of the rotor in the hot section flue gas area; t′ _w,k2 ( h), t″ _{w, k2} (h) are the average wall temperature of the heat storage plate at the inlet and outlet of the rotor tangential (rotation direction) in the secondary air area of the hot section; t′ _{w, k1} (h), t″ _{w, k1} (h) are the average wall temperature of the heat storage plate at the inlet and outlet of the rotor tangential (rotation direction) in the primary air area of the hot section; G(h) is the total mass of the heat transfer elements of the heat storage plate in the hot section; n is the rotor speed; c _{x , h} is the specific heat capacity of the heat storage plate material in the hot section;

Step 5: According to the surface heat transfer equations of the flue gas, primary air and secondary air in the cold section and the heat storage plate, respectively calculate the wall temperature of the heat storage plate on the interface of the flue gas channel in the cold section, list the calibration conditions of the cold section, and check Assumed value of smoke temperature θ _m at the outlet of the hot section (smoke temperature at the inlet of the cold section), output the utilization coefficient value of the hot section and the cold section:

(1) The heat transfer equation between the flue gas in the cold section and the surface of the heat storage plate:

The heat transfer equation between the secondary air in the cold section and the surface of the heat storage plate:

The heat transfer equation between the primary air in the cold section and the surface of the heat storage plate:

(2) by t " _{w, y} (c) = t ' _{w, k2} (c), t " _{w, k2} (c) = t ' _{w, k1} (c), t " _{w, k1} (c) = t ′ _w,y (c) boundary conditions, and in parallel with the three equations in (1) of this step to calculate the heat storage plate wall temperature t′ _w,y (c), t″ _w on the interface of the overall flue gas channel of the preheater _,y (c);

(3) Checking conditions: the heat release of the flue gas in the cold section of the air preheater is equal to the heating amount of the flue gas in the flue gas area to the heat storage plate, and the error is ±2%; that is

Check the hypothetical smoke temperature θ _m at the outlet of the hot section (smoke temperature at the inlet of the cold section) according to the above conditions, and if the conditions are met, output the utilization coefficients of the hot and cold sections calculated in step 3 as the cleaning factor; if the middle conditions cannot be met, then If wrong, repeat steps 2 to 5;

Among them, t′ _w,y (c) and t″ _w,y (c) are respectively the average wall temperature of the heat storage plate at the inlet and outlet of the rotor tangential (rotation direction) in the flue gas area of the cold section; t′ _w,k2 (c ), t″ _w,k2 (c) are the average wall temperature of the heat storage plate at the tangential (rotating direction) inlet and outlet of the rotor in the secondary air area of the cold section; t′ _w,k1 (c), t″ _w,k1 ( c) are the average wall temperature of the heat storage plate at the inlet and outlet of the rotor tangential (rotation direction) in the primary air area of the cold section; G(c) _is the total mass of the heat transfer elements of the heat storage plate in the cold section; The specific heat capacity of the hot plate material;

In addition to coal quality parameters and structural parameters of the furnace, other parameters involved in the above calculation process are all real-time parameters collected in DCS, and the output cleaning factors (utilization coefficients) of the hot and cold sections of the preheater are also real-time value.

The output module makes the real-time parameter graph of the real-time cleaning factors (utilization coefficients) of the hot section and the cold section according to the time distribution through the Plot function in Matlab (the abscissa is the time axis, and the interval is the DCS acquisition time interval, usually 1min; the vertical The coordinates are the value of the utilization coefficient), as the intuitive basis for the monitoring of soot accumulation in the preheater section, the operator judges the timing of soot blowing according to the real-time parameter curves of the hot section and the cold section, and controls the sootblowers at the hot end and cold end to carry out segmentation soot blowing.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the above-mentioned embodiments do not limit the present invention in any form, and all technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

The above are only preferred embodiments of the present invention, and it should be pointed out that for those of ordinary skill in the art, some improvements and modifications can also be made without departing from the principles of the present invention, and these improvements and modifications should also be considered Be the protection scope of the present invention.

Claims (6)

1. a kind of three points of storehouses rotary preheater segmentation dust stratification monitoring method, it is characterised in that comprise the following steps：

Step 1, data collecting module collected as-fired coal matter parameter, structural parameters and boiler real time execution parameter are passed through first；

Step 2, segmentation cleaning gene is carried out according to preheater ash deposition monitoring model by computing module to calculate；

Step 3, exported by way of cleaning gene is distributed in time with curvilinear figure by output module；

Segmentation cleaning gene calculating is carried out in the step 2 according to preheater ash deposition monitoring model by computing module to specifically include Following steps：

(2a), according to the overall thermal balance of preheater, the average excess air coefficient of air side, the total air leakage coefficient of fume side are calculated；

(2b), assume a hot arc outlet cigarette temperature, list hot, cold section of equation of heat balance, calculate cold section of air leakage coefficient and heat Section inlet air mean temperature；

(2c), assume air temperature of a hot arc import, hot arc and cold section of flue gas, First air and Secondary Air are calculated respectively to storing The exothermic coefficient of hot plate, then calculate hot, cold section of heating surface usage factor；

(2d), the surface heat exchanging equation according to hot arc flue gas, First air and Secondary Air and heat accumulation plate, calculates hot arc flue gas and leads to respectively Heat accumulation plate wall temperature on road interface, lists hot arc checking conditions, checks hot arc air temperature assumption value of import；

(2e), the surface heat exchanging equation according to cold section of flue gas, First air and Secondary Air and heat accumulation plate, calculates cold section of flue gas and leads to respectively Heat accumulation plate wall temperature on road interface, lists cold section of section checking conditions, checks hot arc outlet cigarette temperature assumption value, heat outputting, cold section of profit Use coefficient value.

2. a kind of three points of storehouses rotary preheater according to claim 1 is segmented dust stratification monitoring method, it is characterised in that：

Affiliated step (2a) calculates the average excess air coefficient of air side according to the overall thermal balance of preheater, and fume side is always leaked out Coefficient is specially：

(a1) fume side thermal discharge：

(a2) First air absorbs heat：

Secondary Air absorbs heat：

Integrated air recepts the caloric：Wherein

<mrow> <msubsup> <mover> <mi>I</mi> <mo>&amp;OverBar;</mo> </mover> <mi>k</mi> <mrow> <mo>&amp;prime;</mo> <mo>&amp;prime;</mo> </mrow> </msubsup> <mo>=</mo> <msub> <mi>g</mi> <mn>1</mn> </msub> <msubsup> <mi>I</mi> <mrow> <mi>k</mi> <mn>1</mn> </mrow> <mrow> <mo>&amp;prime;</mo> <mo>&amp;prime;</mo> </mrow> </msubsup> <mo>+</mo> <msub> <mi>g</mi> <mn>2</mn> </msub> <msubsup> <mi>I</mi> <mrow> <mi>k</mi> <mn>2</mn> </mrow> <mrow> <mo>&amp;prime;</mo> <mo>&amp;prime;</mo> </mrow> </msubsup> <mo>,</mo> <msub> <mi>g</mi> <mn>1</mn> </msub> <mo>=</mo> <mfrac> <msubsup> <mi>D</mi> <mn>1</mn> <mo>&amp;prime;</mo> </msubsup> <mrow> <msubsup> <mi>D</mi> <mn>1</mn> <mo>&amp;prime;</mo> </msubsup> <mo>+</mo> <msubsup> <mi>D</mi> <mn>2</mn> <mo>&amp;prime;</mo> </msubsup> </mrow> </mfrac> <mo>,</mo> <msub> <mi>g</mi> <mn>2</mn> </msub> <mo>=</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>g</mi> <mn>1</mn> </msub> <mo>;</mo> </mrow>

(a3) the average excess air coefficient of air side is calculated according to actual measurement preheater Secondary Air average discharge：

Wherein

(a4) according to thermal balance Q_y=Q_k, (a1) and (a2) in this step of simultaneous calculates the total air leakage coefficient Δ α of fume side；

Wherein, Q_yFor overall flue gas thermal discharge；Q_kRecepted the caloric for integrated air；Q_k1Recepted the caloric for one piece wind；Q_k2For entirety Secondary Air recepts the caloric；I_y′、I_y" it is respectively flue gas import and export enthalpy；I_k1′、I_k1" it is respectively First air import and export air enthalpy；I_k2′、 I_k2" it is respectively Secondary Air import and export air enthalpy；For the average enthalpy of air side import and export；D₁' it is First air inlet flow rate； D₂′、D₂" it is Secondary Air import and export flow；V⁰For theoretical air volume；For boiler errors；g₁、g₂Respectively first and second Wind flow accounts for the share of total air mass flow；For the average excess coefficient of air side；Δ α is the lateral fume side air leakage coefficient of air；ρ_k For atmospheric density；B_jTo calculate Coal-fired capacity.

3. a kind of three points of storehouses rotary preheater according to claim 1 is segmented dust stratification monitoring method, it is characterised in that：Step Step (2b), one hot arc of hypothesis export cigarette temperature belonging to rapid, list hot, cold section of equation of heat balance, calculate cold section of air leakage coefficient And hot arc inlet air mean temperature is specially：

Assuming that hot arc exit gas temperature is θ_m

(b1) hot arc equation of heat balance is set up：

(b2) cold section of equation of heat balance is set up：

(b3) according to flue gas enthalpy temperature table, by assumption value θ_mUtilize interpolation calculation I_y,m；

(b4) (b1) and (b2) and condition Δ α in this step of simultaneous_h+Δα_c=Δ α, calculates hot, cold section of air leakage coefficient Δ α_h、Δα_cWith the average enthalpy of hot arc inlet air

(b5) according to air enthalpy temperature table, byT is obtained using interpolation method_k,m；

Wherein, θ_mFor hot arc exit gas temperature；I_y′、I_y" it is respectively flue gas import and export enthalpy, I_y,mFor hot arc exiting flue gas enthalpy, t_k,mFor hot arc inlet air mean temperature；The average enthalpy of hot arc inlet air；Δα_h、Δα_cRespectively hot, cold section of air is lateral Fume side air leakage coefficient；For the average excess coefficient of air side.

4. a kind of three points of storehouses rotary preheater according to claim 1 is segmented dust stratification monitoring method, it is characterised in that：Institute State step (2c) and assume air temperature of a hot arc import, hot arc and cold section of flue gas, First air and Secondary Air pair are calculated respectively The exothermic coefficient of heat accumulation plate, then calculate hot, cold section of heating surface usage factor and be specially：

(c1) it is t to assume air temperature of hot arc import_k1,m, according to t_k,m=g₁t_k1,m+g₂t_k2,mObtain hot arc import secondary air temperature Spend t_k2,m；

(c2) hot, cold section of flue gas mean temperature：

Hot, cold section of First air mean temperature：

Hot, cold section of Secondary Air mean temperature：

(c3) hot arc mean temperature difference：

Cold section of mean temperature difference：

(c4) hot arc heat transfer coefficient：

Cold section of heat transfer coefficient：

(c5) hot arc flue gas flow rate：

Cold section of flue gas flow rate：

Hot arc First air flow velocity：

Cold section of First air flow velocity：

Hot arc Secondary Air flow velocity：

Cold section of Secondary Air flow velocity：(wherein )

(c6) hot arc fume side coefficient of convective heat transfer：

Cold section of fume side coefficient of convective heat transfer：

Hot arc First air side coefficient of convective heat transfer：

Cold section of First air side coefficient of convective heat transfer：

Hot arc Secondary Air side coefficient of convective heat transfer：

Cold section of Secondary Air side coefficient of convective heat transfer：

Wherein

(c7) hot arc usage factor：

Cold section of usage factor：

Wherein, (h), (c) represent hot arc and cold section respectively；Subscript y, k1, k2 represent flue gas, First air and Secondary Air respectively；θ′、 θ " is respectively the overall smoke entrance temperature of preheater；t′_k1、t″_k1Preheater one piece wind import and export temperature is represented respectively； t′_k2、t″_k2The respectively overall Secondary Air import and export temperature of preheater；For flue gas mean temperature；Respectively one, two Secondary wind mean temperature；Δ T is logarithmic mean temperature difference (LMTD)；K is heat transfer coefficient；W is flow velocity；Q is thermal discharge；F_yFor flue gas flow area Product；F_k1、F_k2Respectively primary and secondary air actual internal area；V_yFor actual flue gas volume；α is coefficient of convective heat transfer；d_eqFor accumulation of heat Plate equivalent diameter；Re is Reynolds number；Pr is Prandtl number；λ is thermal conductivity factor；ν is kinematic viscosity；Z is accumulation of heat template coefficient； C_t、C_lIt is related to correction factor in respectively calculating；H is heating surface area；x_y、x_k1、x_k2Respectively flue gas, First air and Secondary Air are logical Road heating surface area accounts for the share of total heating surface product；ξ is that can characterize the usage factor of heating surface clean-up performance, θ_mGo out for hot arc Mouth flue-gas temperature.

5. a kind of three points of storehouses rotary preheater according to claim 1 is segmented dust stratification monitoring method, it is characterised in that：Institute Step (2d) is stated according to hot arc flue gas, First air and Secondary Air and the surface heat exchanging equation of heat accumulation plate, hot arc flue gas is calculated respectively Heat accumulation plate wall temperature on passage interface, lists hot arc checking conditions, checks hot arc air temperature assumption value of import and is specially：

(d1) hot arc flue gas and heat accumulation plate surface heat exchanging equation are set up：

<mrow> <msub> <mi>B</mi> <mi>j</mi> </msub> <msub> <mi>Q</mi> <mi>y</mi> </msub> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <mo>=</mo> <mi>&amp;xi;</mi> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <msub> <mi>&amp;alpha;</mi> <mi>y</mi> </msub> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <msub> <mi>x</mi> <mi>y</mi> </msub> <mi>H</mi> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <mo>&amp;lsqb;</mo> <mover> <mi>&amp;theta;</mi> <mo>&amp;OverBar;</mo> </mover> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <mo>-</mo> <mn>0.5</mn> <mrow> <mo>(</mo> <msubsup> <mi>t</mi> <mrow> <mi>w</mi> <mo>,</mo> <mi>y</mi> </mrow> <mo>&amp;prime;</mo> </msubsup> <mo>(</mo> <mi>h</mi> <mo>)</mo> <mo>+</mo> <msubsup> <mi>t</mi> <mrow> <mi>w</mi> <mo>,</mo> <mi>y</mi> </mrow> <mrow> <mo>&amp;prime;</mo> <mo>&amp;prime;</mo> </mrow> </msubsup> <mo>(</mo> <mi>h</mi> <mo>)</mo> <mo>)</mo> </mrow> <mo>&amp;rsqb;</mo> <mo>;</mo> </mrow>

Set up hot arc Secondary Air and heat accumulation plate surface heat exchanging equation：

<mrow> <msub> <mi>B</mi> <mi>j</mi> </msub> <msub> <mi>Q</mi> <mrow> <mi>k</mi> <mn>2</mn> </mrow> </msub> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <mo>=</mo> <mi>&amp;xi;</mi> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <msub> <mi>&amp;alpha;</mi> <mrow> <mi>k</mi> <mn>2</mn> </mrow> </msub> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <msub> <mi>x</mi> <mrow> <mi>k</mi> <mn>2</mn> </mrow> </msub> <mi>H</mi> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <mo>&amp;lsqb;</mo> <mn>0.5</mn> <mrow> <mo>(</mo> <msubsup> <mi>t</mi> <mrow> <mi>w</mi> <mo>,</mo> <mi>k</mi> <mn>2</mn> </mrow> <mo>&amp;prime;</mo> </msubsup> <mo>(</mo> <mi>h</mi> <mo>)</mo> <mo>+</mo> <msubsup> <mi>t</mi> <mrow> <mi>w</mi> <mo>,</mo> <mi>k</mi> <mn>2</mn> </mrow> <mrow> <mo>&amp;prime;</mo> <mo>&amp;prime;</mo> </mrow> </msubsup> <mo>(</mo> <mi>h</mi> <mo>)</mo> <mo>)</mo> </mrow> <mo>-</mo> <msub> <mover> <mi>t</mi> <mo>&amp;OverBar;</mo> </mover> <mrow> <mi>k</mi> <mn>2</mn> </mrow> </msub> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <mo>&amp;rsqb;</mo> <mo>;</mo> </mrow>

Set up hot arc First air and heat accumulation plate surface heat exchanging equation：

<mrow> <msub> <mi>B</mi> <mi>j</mi> </msub> <msub> <mi>Q</mi> <mrow> <mi>k</mi> <mn>1</mn> </mrow> </msub> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <mo>=</mo> <mi>&amp;xi;</mi> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <msub> <mi>&amp;alpha;</mi> <mrow> <mi>k</mi> <mn>1</mn> </mrow> </msub> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <msub> <mi>x</mi> <mrow> <mi>k</mi> <mn>1</mn> </mrow> </msub> <mi>H</mi> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <mo>&amp;lsqb;</mo> <mn>0.5</mn> <mrow> <mo>(</mo> <msubsup> <mi>t</mi> <mrow> <mi>w</mi> <mo>,</mo> <mi>k</mi> <mn>1</mn> </mrow> <mo>&amp;prime;</mo> </msubsup> <mo>(</mo> <mi>h</mi> <mo>)</mo> <mo>+</mo> <msubsup> <mi>t</mi> <mrow> <mi>w</mi> <mo>,</mo> <mi>k</mi> <mn>1</mn> </mrow> <mrow> <mo>&amp;prime;</mo> <mo>&amp;prime;</mo> </mrow> </msubsup> <mo>(</mo> <mi>h</mi> <mo>)</mo> <mo>)</mo> </mrow> <mo>-</mo> <msub> <mover> <mi>t</mi> <mo>&amp;OverBar;</mo> </mover> <mrow> <mi>k</mi> <mn>1</mn> </mrow> </msub> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <mo>&amp;rsqb;</mo> <mo>;</mo> </mrow>

(d2) by t "_w,y(h)=t '_w,k2(h)、t″_w,k2(h)=t '_w,k1(h)、t″_w,k1(h)=t '_w,y(h) boundary condition, it is in parallel Three equations calculate heat accumulation plate wall temperature t ' on the overall exhaust gases passes interface of preheater in vertical (d1)_w,y(h)、t″_w,y(h)；

(d3) checking conditions：Air preheater hot arc flue gas thermal discharge is equal to flue gas area flue gas to the heating amount of heat accumulation plate, error ± 2%；I.e.

The air temperature t of hot arc import assumed is checked according to above-mentioned condition_k1,m, assume correct if condition is met,

Carry out step (2e)；Mistake is assumed if it can not meet condition, repeat step (2c) arrives (2d)；

Wherein, t '_w,y(h)、t″_w,y(h) it is respectively heat accumulation plate mean wall temperature at the tangential import and export of hot arc smoke-gas area rotor； t′_w,k2(h)、t″_w,k2(h) it is respectively heat accumulation plate mean wall temperature at the tangential import and export of hot arc Secondary Air region rotor；t′_w,k1(h)、 t″_w,k1(h) it is respectively heat accumulation plate mean wall temperature at the tangential import and export of hot arc First air region rotor；G (h) is hot arc heat accumulation plate Heat transfer element gross mass；N is rotor speed；c_x,hFor the specific heat capacity of hot arc accumulation of heat plate material；ξ (h) is hot arc usage factor, ξ (c) it is cold section of usage factor.

6. a kind of three points of storehouses rotary preheater according to claim 1 is segmented dust stratification monitoring method, it is characterised in that institute Step (2e) is stated according to cold section of flue gas, First air and Secondary Air and the surface heat exchanging equation of heat accumulation plate, cold section of flue gas is calculated respectively Heat accumulation plate wall temperature on passage interface, lists cold section of section checking conditions, checks hot arc outlet cigarette temperature assumption value, heat outputting, cold section Usage factor value is specially：

(e1) cold section of flue gas and heat accumulation plate surface heat exchanging equation：

<mrow> <msub> <mi>B</mi> <mi>j</mi> </msub> <msub> <mi>Q</mi> <mi>y</mi> </msub> <mrow> <mo>(</mo> <mi>c</mi> <mo>)</mo> </mrow> <mo>=</mo> <mi>&amp;xi;</mi> <mrow> <mo>(</mo> <mi>c</mi> <mo>)</mo> </mrow> <msub> <mi>&amp;alpha;</mi> <mi>y</mi> </msub> <mrow> <mo>(</mo> <mi>c</mi> <mo>)</mo> </mrow> <msub> <mi>x</mi> <mi>y</mi> </msub> <mi>H</mi> <mrow> <mo>(</mo> <mi>c</mi> <mo>)</mo> </mrow> <mo>&amp;lsqb;</mo> <mover> <mi>&amp;theta;</mi> <mo>&amp;OverBar;</mo> </mover> <mrow> <mo>(</mo> <mi>c</mi> <mo>)</mo> </mrow> <mo>-</mo> <mn>0.5</mn> <mrow> <mo>(</mo> <msubsup> <mi>t</mi> <mrow> <mi>w</mi> <mo>,</mo> <mi>y</mi> </mrow> <mo>&amp;prime;</mo> </msubsup> <mo>(</mo> <mi>c</mi> <mo>)</mo> <mo>+</mo> <msubsup> <mi>t</mi> <mrow> <mi>w</mi> <mo>,</mo> <mi>y</mi> </mrow> <mrow> <mo>&amp;prime;</mo> <mo>&amp;prime;</mo> </mrow> </msubsup> <mo>(</mo> <mi>c</mi> <mo>)</mo> <mo>)</mo> </mrow> <mo>&amp;rsqb;</mo> <mo>;</mo> </mrow>

Cold section of Secondary Air and heat accumulation plate surface heat exchanging equation：

<mrow> <msub> <mi>B</mi> <mi>j</mi> </msub> <msub> <mi>Q</mi> <mrow> <mi>k</mi> <mn>2</mn> </mrow> </msub> <mrow> <mo>(</mo> <mi>c</mi> <mo>)</mo> </mrow> <mo>=</mo> <mi>&amp;xi;</mi> <mrow> <mo>(</mo> <mi>c</mi> <mo>)</mo> </mrow> <msub> <mi>&amp;alpha;</mi> <mrow> <mi>k</mi> <mn>2</mn> </mrow> </msub> <mrow> <mo>(</mo> <mi>c</mi> <mo>)</mo> </mrow> <msub> <mi>x</mi> <mrow> <mi>k</mi> <mn>2</mn> </mrow> </msub> <mi>H</mi> <mrow> <mo>(</mo> <mi>c</mi> <mo>)</mo> </mrow> <mo>&amp;lsqb;</mo> <mn>0.5</mn> <mrow> <mo>(</mo> <msubsup> <mi>t</mi> <mrow> <mi>w</mi> <mo>,</mo> <mi>k</mi> <mn>2</mn> </mrow> <mo>&amp;prime;</mo> </msubsup> <mo>(</mo> <mi>c</mi> <mo>)</mo> <mo>+</mo> <msubsup> <mi>t</mi> <mrow> <mi>w</mi> <mo>,</mo> <mi>k</mi> <mn>2</mn> </mrow> <mrow> <mo>&amp;prime;</mo> <mo>&amp;prime;</mo> </mrow> </msubsup> <mo>(</mo> <mi>c</mi> <mo>)</mo> <mo>)</mo> </mrow> <mo>-</mo> <msub> <mover> <mi>t</mi> <mo>&amp;OverBar;</mo> </mover> <mrow> <mi>k</mi> <mn>2</mn> </mrow> </msub> <mrow> <mo>(</mo> <mi>c</mi> <mo>)</mo> </mrow> <mo>&amp;rsqb;</mo> <mo>;</mo> </mrow>

Cold section of First air and heat accumulation plate surface heat exchanging equation：

<mrow> <msub> <mi>B</mi> <mi>j</mi> </msub> <msub> <mi>Q</mi> <mrow> <mi>k</mi> <mn>1</mn> </mrow> </msub> <mrow> <mo>(</mo> <mi>c</mi> <mo>)</mo> </mrow> <mo>=</mo> <mi>&amp;xi;</mi> <mrow> <mo>(</mo> <mi>h</mi> <mo>)</mo> </mrow> <msub> <mi>&amp;alpha;</mi> <mrow> <mi>k</mi> <mn>1</mn> </mrow> </msub> <mrow> <mo>(</mo> <mi>c</mi> <mo>)</mo> </mrow> <msub> <mi>x</mi> <mrow> <mi>k</mi> <mn>1</mn> </mrow> </msub> <mi>H</mi> <mrow> <mo>(</mo> <mi>c</mi> <mo>)</mo> </mrow> <mo>&amp;lsqb;</mo> <mn>0.5</mn> <mrow> <mo>(</mo> <msubsup> <mi>t</mi> <mrow> <mi>w</mi> <mo>,</mo> <mi>k</mi> <mn>1</mn> </mrow> <mo>&amp;prime;</mo> </msubsup> <mo>(</mo> <mi>c</mi> <mo>)</mo> <mo>+</mo> <msubsup> <mi>t</mi> <mrow> <mi>w</mi> <mo>,</mo> <mi>k</mi> <mn>1</mn> </mrow> <mrow> <mo>&amp;prime;</mo> <mo>&amp;prime;</mo> </mrow> </msubsup> <mo>(</mo> <mi>c</mi> <mo>)</mo> <mo>)</mo> </mrow> <mo>-</mo> <msub> <mover> <mi>t</mi> <mo>&amp;OverBar;</mo> </mover> <mrow> <mi>k</mi> <mn>1</mn> </mrow> </msub> <mrow> <mo>(</mo> <mi>c</mi> <mo>)</mo> </mrow> <mo>&amp;rsqb;</mo> <mo>;</mo> </mrow>

(e2) by t "_w,y(c)=t '_w,k2(c), t "_w,k2(c)=t '_w,k1(c), t "_w,k1(c)=t '_w,y(c) boundary condition, it is in parallel Found three equations in (e1) of this step and calculate heat accumulation plate wall temperature t ' on the overall exhaust gases passes interface of preheater_w,y(c), t″_w,y(c)；

(e3) checking conditions：Cold section of flue gas thermal discharge of air preheater is equal to flue gas area flue gas to the heating amount of heat accumulation plate, error ± 2%；I.e.

The hot arc outlet cigarette temperature θ assumed is checked according to above-mentioned condition_m, if exporting calculated in step 3 hot, cold if meeting condition The usage factor of section is used as cleaning gene；Mistake is assumed if it can not meet condition, repeat step (2b) arrives (2e)；

Wherein, t '_w,y(c)、t″_w,y(c) it is respectively heat accumulation plate mean wall temperature at the cold section of tangential import and export of smoke-gas area rotor； t′_w,k2(c)、t″_w,k2(c) it is respectively the cold section of tangential import and export heat accumulation plate mean wall temperature of Secondary Air region rotor；t′_w,k1(c)、 t″_w,k1(c) it is respectively the cold section of tangential import and export heat accumulation plate mean wall temperature of First air region rotor；G (c) is that cold section of heat accumulation plate is passed Thermal element gross mass；c_x,cFor the specific heat capacity of cold section of accumulation of heat plate material.