CN112085367B - Condenser dirt coefficient online monitoring method and system - Google Patents

Condenser dirt coefficient online monitoring method and system Download PDF

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CN112085367B
CN112085367B CN202010906657.XA CN202010906657A CN112085367B CN 112085367 B CN112085367 B CN 112085367B CN 202010906657 A CN202010906657 A CN 202010906657A CN 112085367 B CN112085367 B CN 112085367B
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林闽城
华敏
谢尉扬
赵佳骏
宋涛
孙永平
王飞
王林林
保佳伟
雍天瑞
王志峰
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Zhejiang Energy Group Research Institute Co Ltd
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Abstract

The invention relates to a condenser fouling coefficient online monitoring method, which comprises the following steps: step 101, acquiring real-time operation data through a real-time operation data acquisition module; and 102, preprocessing the real-time running data through a data preprocessing module. The invention has the beneficial effects that: the invention can calculate the dirty coefficient of the condenser in real time by combining the actual condition and the structural characteristic of the operation of the condenser, and comprehensively considers the dirty condition of the condenser pipe bundle by adopting the dirty coefficient. The method has the advantages that the purpose of obtaining the condenser fouling coefficient with relatively small error is achieved, the change condition of the fouling coefficient along with time is presented on the display device in the form of graphs and curves, operating personnel can be helped to monitor the operating state of the condenser more intuitively, a basis can be provided for determining the optimal vacuum of a unit and optimizing the cold end, and reference is provided for cleaning the condenser.

Description

Condenser dirt coefficient online monitoring method and system
Technical Field
The invention belongs to the technical field of power generation, and particularly relates to a method and a system for monitoring a fouling coefficient of a condenser on line.
Background
The condenser is one of main auxiliary equipment of a coal-fired power plant, has the functions of condensing the exhaust steam of the steam turbine into water and establishing and maintaining a certain vacuum at the exhaust port of the low-pressure cylinder of the steam turbine, and the working performance of the condenser directly influences the economical efficiency and the safety of the operation of the whole unit. The heat exchange characteristic of the condenser is one of quantitative indexes for describing the working performance of the condenser, can be used for monitoring the running state of the condenser, and meanwhile provides a basis for determining the optimal vacuum of a unit and optimizing a cold end.
The heat transfer characteristics of the condenser are related to the parameters of the cooling water, in addition to the fouling conditions of the condenser tube bundle. The dirty condition of the tube bundle of the condenser is generally judged by a thermal resistance method, a heat transfer coefficient method, a water flow resistance method and the like, and is generally expressed by a cleaning coefficient, namely the ratio of the heat transfer coefficient of the current tube bundle to an ideal heat transfer coefficient. The cleaning coefficient determination method comprises two methods at present, one is to look up a table according to a cooling mode and water quality to obtain a constant, for example, a Chinese patent with the application number of 201110231492.1, the method cannot reflect the change condition of the fouling coefficient in the actual operation process; the other method is to obtain the total heat transfer coefficient of the condenser through inverse calculation according to an empirical formula, and typical empirical formulas include a Bourman formula and an American society for Heat transfer HEI formula, but the empirical formula only considers main influence factors such as load, circulating water temperature, circulating water flow, heat transfer pipe materials and wall thickness and cannot cover the respective unique structural characteristics and operating conditions of all condensers.
Therefore, in the actual application process, the cleaning coefficient calculated by an empirical formula has certain deviation from the actual dirt condition. How to accurately express the dirt condition of the condenser and how to effectively obtain the dirt condition numerical value of the condenser with relatively small error still is a technical problem for scientific researchers.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a method and a system for monitoring the fouling coefficient of a condenser on line.
This kind of dirty coefficient on-line monitoring system of condenser includes: the system comprises a real-time operation data acquisition module, a data preprocessing module, a contamination coefficient calculation module, a data storage module and a foreground display module; the real-time operation data acquisition module is connected with the data storage module and the data preprocessing module; the data preprocessing module is connected with the contamination coefficient calculating module, the data storage module and the foreground display module; and the contamination coefficient calculating module is connected with the data storage module and the foreground display module.
Preferably, the display form of the foreground display module comprises a table, a curve and a text prompt; the table comprises condenser operating pressure, calculated pressure and a deviation of the condenser operating pressure and the calculated pressure, circulating water operating temperature difference, calculated temperature difference and a deviation of the circulating water operating temperature difference and the calculated temperature difference, a condenser operating end difference, a calculated end difference and a deviation of the condenser operating end difference and the calculated end difference, a condenser reference pollution coefficient, a corrected pollution coefficient, a deviation of the corrected pollution coefficient and an alarm prompt in a data preprocessing module; the curves comprise a condenser operating pressure and calculated pressure change curve along with time, a circulating water operating temperature difference and calculated temperature difference change curve along with time, a condenser operating end difference and calculated end difference change curve along with time, and a condenser reference fouling coefficient and corrected fouling coefficient change curve along with time.
Preferably, the foreground display module adopts a PC liquid crystal display as the display device.
The monitoring method of the condenser fouling coefficient on-line monitoring system specifically comprises the following steps:
step 101, acquiring real-time operation data through a real-time operation data acquisition module;
step 102, preprocessing real-time running data through a data preprocessing module;
103, receiving the data processed by the data preprocessing module by using a contamination coefficient calculation module, calculating a reference contamination coefficient, and sending a calculation result to the data storage module and the foreground display module:
step 104, calculating the pressure of the condenser:
step 105, judging that the condenser calculates condenser pressure p cc And operating pressure p c Whether the deviation δ therebetween satisfies the requirement, the deviation δ is expressed as:
Figure GDA0003714483330000021
in the above formula, p cc Is condenser pressure, p c Is the operating pressure; if the | δ | is greater than 0.05, the deviation δ does not meet the requirement, and the step 106 is executed; if the | δ | ≦ 0.05, the deviation δ satisfies the requirement, and execute step 107;
step 106, updating the pollution coefficient:
if delta<0, then beta cb update ＝β cb -0.001; if delta>0, then beta cb update ＝β cb +0.001；β cb To update the pre-fouling factor, beta cb update Is the updated fouling factor; returning to execute the step 104 to the step 105, and recalculating the condenser pressure;
step 107, correcting the pollution coefficient beta calculated by the pollution coefficient calculating module cx And judging whether the condenser is cleaned or not as a judgment basis for whether the condenser is cleaned or not.
Preferably, the step 102 specifically includes the following steps:
step 10201, judging the running state of the unit through a data preprocessing module, and judging whether the unit is shut down: if the unit load Q<If the unit is a, judging that the unit is stopped, wherein a is a positive number less than or equal to 5 and has a unit of MW; if the circulating water flow V w <If the unit is b, judging that the unit is stopped; b is a positive number less than or equal to 10, and the unit is kg/s; if there are multiple circulating water pumps, the current I of each circulating water pump<If the unit is determined to be stopped, judging that the unit is stopped; wherein c is a positive number less than or equal to 5 and has a unit of A; if the unit stops, the data preprocessing module sends the result to the data storage module and feeds the result back to the foreground display module for display;
step 10202, determining the range of the real-time operation data, firstly setting the range of the high-low limited range of each real-time operation data, then respectively comparing each real-time operation data with the corresponding range of the high-low limited range, if the real-time operation data is not in the range, determining that the real-time operation data exceeds the range, sending the result to a data storage module by a data preprocessing module, and feeding alarm information back to a foreground display module for display;
step 10203, carrying out rationality judgment on the real-time operation data, and if the outlet temperature of the circulating water of the condenser is less than or equal to the inlet temperature of the circulating water of the condenser, or the end difference of the condenser is less than or equal to 0, or the outlet pressure of the circulating water of the condenser is more than or equal to the inlet pressure of the circulating water of the condenser, judging that the data is unreasonable and sending the result to the data storage module by the data preprocessing module and feeding the result back to the foreground display module for display;
step 10204, for the data using double or multiple measuring points, carrying out arithmetic mean on the measuring point data, and taking the arithmetic mean as the final value of the measuring point.
Preferably, the step 103 specifically includes the following steps:
step 10301, obtaining a condenser heat load Q through curve fitting by utilizing the heat balance map data c In MW, the curve fitting results are:
Figure GDA0003714483330000031
in the above formula, a 0 Is a constant term of a polynomial, a 1 、a 2 、...a i ...、a k Is a coefficient term of a polynomial, k is a positive integer greater than 0, Q is unit load and has a unit of MW; q c Is the heat load of the condenser, and the unit is MW;
step 10302, according to the heat load Q of the condenser c The actual total heat transfer coefficient K of the condenser is obtained by using a condenser heat balance equation, and the unit is W/(m) 2 ·℃)：
Figure GDA0003714483330000032
In the above formula, K is the actual total heat transfer coefficient of the condenser, and the unit is W/(m) 2 DEG C.); f is the heat exchange area of the condenser and the unit is m 2 ，Δt m Is logarithmic mean heat transfer temperature difference of a condenser, and the unit is temperature delta t m Calculating the exhaust temperature of the condenser and the temperature of an inlet and an outlet of circulating water; q c Is the heat load of the condenser, and the unit is MW;
step 10303, obtaining a reference fouling coefficient by inverse calculation by using an empirical formula according to the actual total heat transfer coefficient of the condenser, wherein the empirical formula comprises a Coleman formula and an American society for Heat transfer (HEI) formula;
wherein, the HEI formula is as follows:
K＝K 0 ×β c ×β m ×β t
in the above formula, K 0 Is the basic heat transfer coefficient and has the unit of W/(m) 2 The temperature is measured according to the external diameter of the cooling pipe and the circulating water flow speed; beta is a c The coefficient of fouling of the cooling surface of the condenser; beta is a m Checking a table according to the pipe and the wall thickness to obtain a constant for the pipe and the wall thickness correction coefficient of the cooling pipe; beta is a t The correction coefficient is obtained by looking up a table according to the inlet water temperature of the circulating water; k is the actual total heat transfer coefficient of the condenser and has the unit of W/(m) 2 ·℃)；
The calculation formula for obtaining the reference fouling coefficient is as follows:
Figure GDA0003714483330000041
in the above formula, K is the actual total heat transfer coefficient of the condenser, and the unit is W/(m) 2 ·℃)；K 0 Is the basic heat transfer coefficient and has the unit of W/(m) 2 Looking up a table according to the outer diameter of the cooling pipe and the circulating water flow speed; beta is a m Looking up a table according to the pipe and the wall thickness to obtain a constant for the pipe and the wall thickness correction coefficient of the cooling pipe; beta is a t The correction coefficient is obtained by looking up a table according to the inlet water temperature of the circulating water; beta is a beta c And the coefficient of fouling of the cooling surface of the condenser.
Preferably, the step 104 specifically includes the following steps:
step 10401, calculating the temperature difference Δ t between the circulating water inlet and the circulating water outlet of the condenser according to the heat balance relationship of the condenser, wherein the unit is ℃:
Figure GDA0003714483330000042
in the above formula, Δ h is the enthalpy difference of the exhaust steam in the condensation process of the condenser, and the unit is kJ/kg; c. C p The specific heat at constant pressure of water is expressed in kJ/(kg DEG C); d w Is the flow rate of circulating water, and the unit is kg/s; d k The unit is kg/s for the flow of the dead steam;
step 10402, calculating condenser end difference δ t according to the condenser heat balance relation, unit is ℃:
Figure GDA0003714483330000043
in the above formula, Δ t is the temperature difference between the circulating water inlet and the circulating water outlet of the condenser, and the unit is; c. C p The specific heat at constant pressure of water is expressed in kJ/(kg DEG C); d w Is the flow rate of circulating water, and the unit is kg/s; delta t is condenser end difference, and the unit is; KA is the total heat transfer coefficient of the condenser, and the unit is W/(m) 2 DEG C), wherein A is the heat exchange area of the condenser and the unit is m 2 ；
Step 10403, calculating the saturation temperature t of the condenser s The unit is:
t s ＝t w,in +Δt+δt
in the above formula, t w,in The temperature of a circulating water inlet of a condenser is measured in units of temperature; delta t is the temperature difference between the circulating water inlet and the circulating water outlet of the condenser, and the unit is; delta t is condenser end difference, and the unit is;
step 10404, calculating condenser pressure p according to IAPWS-IF1997 formula cc In kPa:
p cc ＝f(t s )
in the above formula, t s Is the saturation temperature of the condenser in℃。
Preferably, the step 107 specifically includes the following steps:
step 10701, correcting the fouling factor beta cx Calculating the average deviation delta between the end difference and the operating end difference of the condenser Delta t average Expressed as:
Figure GDA0003714483330000051
in the above formula, δ δt The deviation calculated for the end difference is expressed as:
Figure GDA0003714483330000052
in the above formula, δ tx Calculated as end difference, δ ty Is the running end difference value;
step 10702, setting a boundary value for cleaning the condenser; if beta is cx <If the boundary value is the boundary value, judging that the condenser needs to be cleaned, and giving a prompt for cleaning the condenser by a foreground display module; if beta is cx And if the temperature is more than or equal to the boundary value, judging that the condenser does not need to be cleaned and prompting.
Preferably, the real-time operation data in step 101 includes: the system comprises a unit load, condenser circulating water inlet and outlet temperature, condenser circulating water inlet and outlet pressure, condenser end difference, circulating water pump current, circulating water pump voltage, circulating water flow, main hot steam pressure, main hot steam temperature, reheat steam pressure, reheat steam temperature, steam extraction pressure, steam extraction temperature, heater water inlet temperature, heater water outlet temperature, heater drainage temperature, main steam flow, water supply flow, condensate flow, attemperation water flow and external steam supply flow.
The invention has the beneficial effects that: the invention can calculate the dirty coefficient of the condenser in real time by combining the actual condition and the structural characteristic of the operation of the condenser, and comprehensively considers the dirty condition of the condenser pipe bundle by adopting the dirty coefficient. The method has the advantages that the purpose of obtaining the condenser fouling coefficient with relatively small error is achieved, the change condition of the fouling coefficient along with time is presented on the display device in the form of graphs and curves, operating personnel can be helped to monitor the operating state of the condenser more intuitively, a basis can be provided for determining the optimal vacuum of a unit and optimizing the cold end, and reference is provided for cleaning the condenser.
Drawings
FIG. 1 is a flow chart of the calculation of the on-line monitoring method of the fouling coefficient of the condenser;
FIG. 2 is a graph of a calculated baseline fouling factor versus a corrected fouling factor in an embodiment of the present invention;
FIG. 3 is a graph of deviation between the end difference of the condenser and the end difference of the condenser from the operation end difference calculated by correcting the fouling factor in the embodiment of the present invention;
fig. 4 is a schematic structural diagram of an online monitoring system for a fouling coefficient of a condenser provided in an embodiment of the present invention.
Description of reference numerals: the system comprises a real-time operation data acquisition module 401, a data preprocessing module 402, a contamination coefficient calculation module 403, a data storage module 404 and a foreground display module 405.
Detailed Description
The present invention will be further described with reference to the following examples. The following examples are set forth merely to aid in the understanding of the invention. It should be noted that, for a person skilled in the art, several modifications can be made to the invention without departing from the principle of the invention, and these modifications and modifications also fall within the protection scope of the claims of the present invention.
According to the embodiment of the invention, the operating pressure of the condenser is taken as a target value, the structural characteristics and the operating conditions of the condenser are comprehensively considered through an iterative algorithm, and a relatively accurate contamination coefficient can be obtained.
Example 1:
referring to fig. 1, fig. 1 is a calculation flowchart of an online condenser fouling coefficient monitoring method according to an embodiment of the present invention, and details of a thermal power generating unit are described below.
Step 101, acquiring real-time operation data. The real-time operating data includes: the system comprises a unit load, the temperature and pressure of a circulating water inlet and a circulating water outlet of a condenser, the pressure and end difference of the condenser, the current and voltage of a circulating water pump, the circulating water flow, the main heat steam pressure and temperature, the reheat steam pressure and temperature, the steam extraction pressure and temperature, the water inlet temperature of a heater, the water outlet temperature of the heater, the drainage temperature of the heater, the main steam, the feed water, the condensed water, the desuperheating water and the external steam supply flow.
Step 102, preprocessing the operation data:
(1) the unit running state is judged, and the shutdown judging method comprises the following steps:
(1-1) if the unit load Q & lt a, a is a positive number less than or equal to 5 and the unit is MW, judging that the unit is stopped;
(1-2) if the flow rate V of the circulating water is high W <B is a positive number less than or equal to 10, and the unit is kg/s, and the unit is judged to be shut down;
(1-3) if the circulating water pump current I < ═ c, c is a positive number less than or equal to 5, and the unit is A; if a plurality of circulating water pumps exist and the current of each water pump is less than or equal to c, judging that the unit is stopped;
in the embodiment, if the unit load Q is less than 3MW, the unit is judged to be stopped and alarm prompt is carried out;
(2) judging the range of the operation data, firstly setting the range of the high-low limited range of each operation data, then respectively comparing each operation data with the corresponding range of the high-low limited range, and if the operation data is not in the range, judging that the operation data exceeds the range and giving an alarm;
(3) judging the rationality of the operation data, and if the outlet temperature of the circulating water of the condenser is less than or equal to the inlet temperature, or the end difference of the condenser is less than or equal to 0, or the outlet pressure of the circulating water of the condenser is more than or equal to the inlet pressure, judging that the data is unreasonable and giving an alarm;
(4) for data using double or multiple measuring points, the data of the measuring points are subjected to arithmetic mean, and the arithmetic mean is taken as the final value of the measuring point.
Step 103, calculating a reference fouling coefficient:
(1) using thermal equilibrium map data to fit via a curveObtaining the heat load Q of the condenser c In MW, the curve fitting results are:
Figure GDA0003714483330000071
in the above formula, a 0 Is a constant term of a polynomial 1、 a 2、...、 a k Is a coefficient term of a polynomial, k is a positive integer greater than 0, Q is unit load and has a unit of MW; q c Is the heat load of the condenser, and the unit is MW;
(2) obtaining the actual total heat transfer coefficient K of the condenser according to the heat load of the condenser by using a condenser heat balance equation, wherein the unit is W/(m) 2 ·℃)：
Figure GDA0003714483330000072
In the above formula, K is the actual total heat transfer coefficient of the condenser, and the unit is W/(m) 2 DEG C.); f is the heat exchange area of the condenser and the unit is m 2 ，Δt m The unit is logarithmic mean heat transfer temperature difference of the condenser, and the logarithmic mean heat transfer temperature difference is calculated according to exhaust temperature of the condenser and inlet and outlet temperature of circulating water; q c Is the heat load of the condenser, and the unit is MW;
(3) and (3) obtaining a reference fouling coefficient by utilizing the HEI formula of the American society for Heat transfer to perform inverse calculation according to the actual total heat transfer coefficient of the condenser:
wherein, the HEI formula is as follows:
K＝K 0 ×β c ×β m ×β t
in the above formula, K 0 Is the basic heat transfer coefficient and has the unit of W/(m) 2 Looking up a table according to the outer diameter of the cooling pipe and the circulating water flow speed; beta is a c The coefficient of fouling of the cooling surface of the condenser; beta is a beta m Looking up a table according to the pipe and the wall thickness to obtain a constant for the pipe and the wall thickness correction coefficient of the cooling pipe; beta is a t The correction coefficient is obtained by looking up a table according to the inlet water temperature of the circulating water; k is the actual total heat transfer coefficient of the condenser and the unit is W/(m) 2 ·℃)；
The calculation formula for obtaining the reference fouling coefficient is as follows:
Figure GDA0003714483330000081
in the above formula, K is the actual total heat transfer coefficient of the condenser, and the unit is W/(m) 2 ·℃)；K 0 Is the basic heat transfer coefficient and has the unit of W/(m) 2 Looking up a table according to the outer diameter of the cooling pipe and the circulating water flow speed; beta is a beta m Looking up a table according to the pipe and the wall thickness to obtain a constant for the pipe and the wall thickness correction coefficient of the cooling pipe; beta is a t The correction coefficient is obtained by looking up a table according to the inlet water temperature of the circulating water; beta is a c The coefficient of fouling of the cooling surface of the condenser;
it should be noted that the HEI formula is a formula commonly used by those skilled in the art, and it is clear how to obtain the parameters in the formula.
Step 104, calculating the pressure of a condenser:
(1) calculating the temperature difference delta t of circulating water inlet and outlet of the condenser according to the heat balance relation of the condenser, wherein the unit is:
Figure GDA0003714483330000082
in the above formula, Δ h is the enthalpy difference of the exhaust steam in the condensation process of the condenser, and the unit is kJ/kg; c. C p The specific heat at constant pressure of water is expressed in kJ/(kg DEG C); d w Is the flow rate of circulating water, and the unit is kg/s; d k The unit is kg/s for the flow of the dead steam;
(2) calculating the condenser end difference delta t according to the heat balance relation of the condenser, wherein the unit is ℃:
Figure GDA0003714483330000083
in the above formula, Δ t is the temperature difference between the circulating water inlet and the circulating water outlet of the condenser, and the unit is; c. C p Is the water contentSpecific heat under pressure, in kJ/(kg. DEG C); d w Is the flow rate of circulating water, and the unit is kg/s; delta t is condenser end difference, and the unit is;
(3) calculating the saturation temperature t of the condenser s The unit is:
t s ＝t w,in +Δt+δt
in the above formula, t w,in The temperature of a circulating water inlet of a condenser is measured in units of temperature; delta t is the temperature difference between the circulating water inlet and the circulating water outlet of the condenser, and the unit is; delta t is condenser end difference, and the unit is;
(4) calculating to obtain the condenser pressure p according to an IAPWS-IF1997 formula cc In kPa:
p cc ＝f(t s )
in the above formula, t s The saturation temperature of the condenser is shown in unit;
step 105, judging that the condenser calculates condenser pressure p cc And operating pressure p c Whether the deviation δ therebetween satisfies the requirement, the deviation δ is expressed as:
Figure GDA0003714483330000091
in the above formula, p cc For condenser pressure, p c Is the operating pressure; if the | δ | is greater than 0.05, the deviation δ does not meet the requirement, and the step 106 is executed; if the | δ | ≦ 0.05, the deviation δ satisfies the requirement, and execute step 107;
step 106, updating the pollution coefficient:
if delta<0, then beta cb update ＝β cb -0.001; if delta>0, then beta cb update ＝β cb +0.001；β cb To update the fouling factor, beta cb update Is the updated fouling coefficient; returning to the step 104 to the step 105, and recalculating the condenser pressure;
step 107, correcting the fouling coefficient beta cx Output as a final result;
referring to fig. 2, fig. 2 is a graph illustrating a reference contamination coefficient and a corrected contamination coefficient calculated in the embodiment.
Because only the influence of the outer diameter of the cooling pipe, the flow speed of circulating water, the pipe material, the wall thickness, the temperature of a circulating water inlet and the dirt of the heat transfer pipe on the heat transfer coefficient is considered in the process of reversely calculating the dirt coefficient by adopting the HEI formula, and other factors such as the influence of the tightness of a condenser on the heat transfer coefficient are not considered independently, the dirt coefficient calculated according to the HEI formula is smaller. It can be seen from fig. 2 that the corrected fouling factor calculation is greater than the reference fouling factor.
Please refer to fig. 3 for the calculation result of the condenser end difference obtained by correcting the fouling factor, and fig. 3 is a graph illustrating the deviation between the condenser end difference and the operating end difference obtained by correcting the fouling factor in the embodiment.
Mean deviation delta of end difference calculation Delta t average It is only 2.20%.
Mean deviation delta of end difference calculation Delta t average Expressed as:
Figure GDA0003714483330000092
in the above formula, δ δt The deviation calculated for the end difference is expressed as:
Figure GDA0003714483330000101
in the formula, delta tx Calculated as end difference, δ ty Is the running end difference value;
compared with the pollution coefficient which is obtained by the traditional method without iterative computation, namely the standard pollution coefficient in the embodiment, the corrected pollution coefficient obtained by iterative computation in the embodiment of the invention takes the operating pressure of the condenser as a target value, comprehensively considers the structural characteristics and the operating conditions of the condenser, and has more accurate computation result.
Example 2:
as a further optimized implementation manner of the present invention, as shown in fig. 4, fig. 4 is a schematic structural diagram of an online condenser fouling coefficient monitoring system provided in an embodiment of the present invention, and details are as follows.
The condenser dirt coefficient on-line monitoring system in the embodiment of the invention comprises: a real-time operation data acquisition module 401, a data preprocessing module 402, a contamination coefficient calculation module 403, a data storage module 404 and a foreground display module 405; the real-time operation data acquisition module 401 is connected with the data storage module 404 and the data preprocessing module 402; the data preprocessing module 402 is connected with a contamination coefficient calculating module 403, a data storage module 404 and a foreground display module 405; the contamination coefficient calculating module 403 is connected to the data storage module 404 and the foreground displaying module 405. The display form of the foreground display module 405 includes tables, curves and text prompts. The foreground display module 405 employs a PC liquid crystal display as a display device.
The real-time operation data acquisition module 401 is configured to acquire and record real-time operation data of the required unit, and send the real-time operation data to the data storage module and the data preprocessing module.
A data preprocessing module 402, configured to preprocess the real-time running data, and make a judgment on whether to perform a contamination coefficient calculation,
(1) according to the judgment result of the unit running state, if the unit stops, the result is sent to the data storage module and fed back to the foreground display module to make a corresponding prompt;
(2) according to the judgment result of the range of the operation data, if the data is out of limit, the result is sent to the data storage module and fed back to the foreground display module, and a corresponding prompt is given;
(3) judging the reasonableness of the running data, if the running data is unreasonable, sending the result to a data storage module, feeding the result back to a foreground display module and making a corresponding prompt;
(4) and if no alarm prompt exists, the result is sent to the data storage module and the contamination coefficient calculation module.
And the contamination coefficient calculating module 403 is configured to receive the processed data, calculate a condenser reference contamination coefficient and a condenser pressure under the current operating condition, perform iterative calculation to obtain a corrected contamination coefficient of the condenser, and send a calculation result to the data storage module and the foreground display module.
The data storage module 404 is configured to receive and store the unit real-time operation data sent by the real-time operation data acquisition module, the data preprocessing result sent by the data preprocessing module, and the calculation result sent by the contamination coefficient calculation module.
A foreground display module 405, configured to display the calculation result of the contamination coefficient calculation module, the alarm prompt in the data preprocessing module, and the prompt indicating whether to perform condenser cleaning, which is obtained from the calculation result of the contamination coefficient calculation module, and present the prompt in the form of a table and a curve,
the method for judging whether the condenser needs to be cleaned comprises the following steps:
1) setting a boundary value beta for cleaning a condenser c cleaning ＝0.70；
2) If beta is cx <0.7, judging that the condenser needs to be cleaned, and giving a prompt for cleaning the condenser;
3) if beta is cx If the steam condenser is not less than 0.7, judging that the steam condenser does not need to be cleaned and prompting;
the foreground display module displays a table comprising condenser running pressure, calculated pressure and a deviation of the condenser running pressure and the calculated pressure, circulating water running temperature difference, calculated temperature difference and a deviation of the circulating water running temperature difference and the calculated temperature difference, condenser running end difference, calculated end difference and a deviation of the condenser running end difference and the calculated end difference, condenser reference pollution coefficient, corrected pollution coefficient and a deviation of the corrected pollution coefficient and the deviation of the corrected pollution coefficient and an alarm prompt in the data preprocessing module 402; the curves comprise a condenser operating pressure and calculated pressure change curve along with time, a circulating water operating temperature difference and calculated temperature difference change curve along with time, a condenser operating end difference and calculated end difference change curve along with time, and a condenser reference fouling coefficient and corrected fouling coefficient change curve along with time; the display device is a PC liquid crystal display.
The on-line monitoring system for the fouling coefficient of the condenser, provided by the invention, can calculate the fouling coefficient of the condenser in real time, and display the change condition of the fouling coefficient along with time on display equipment in the form of a chart and a curve, so that operators can be helped to monitor the operation state of the condenser more intuitively, and reference is provided for cleaning the condenser.

Claims (4)

1. A monitoring method of an on-line monitoring system for the fouling coefficient of a condenser is characterized by comprising the following steps:
step 101, acquiring real-time operation data through a real-time operation data acquisition module (401);
step 102, preprocessing real-time running data through a data preprocessing module (402);
step 103, receiving the data processed by the data preprocessing module (402) by using the smudge coefficient calculating module (403), calculating a reference smudge coefficient, and sending the calculation result to the data storage module (404) and the foreground display module (405):
step 10301, obtaining the heat load of the condenser by curve fitting by utilizing the heat balance map dataQ c In MW, the curve fitting results are:
Figure 404782DEST_PATH_IMAGE001
in the above formula, the first and second carbon atoms are,
Figure DEST_PATH_IMAGE002
is a constant term of the polynomial expression,
Figure 413932DEST_PATH_IMAGE003
is a coefficient term of the polynomial expression,kis a positive integer greater than 0 and is,Qunit load is unit MW;Q c is the heat load of the condenser, and the unit is MW;
step 10302, according to the heat load of the condenserQ c Obtaining the actual total heat transfer coefficient of the condenser by utilizing the heat balance equation of the condenserKThe unit is W/(m) 2 ·℃）：
Figure DEST_PATH_IMAGE004
In the above-mentioned formula, the compound has the following structure,Kthe unit is W/(m) for the actual total heat transfer coefficient of the condenser 2 ·℃）；FIs the heat exchange area of the condenser, and the unit is m 2 ，Δt m Is the logarithmic mean heat transfer temperature difference of the condenser, and the unit is the temperature deltat m Calculating the exhaust temperature of the condenser and the temperature of an inlet and an outlet of circulating water;Q c is the heat load of the condenser, and the unit is MW;
step 10303, obtaining a reference fouling coefficient by inverse calculation by using an empirical formula according to the actual total heat transfer coefficient of the condenser, wherein the empirical formula comprises a Coleman formula and an American society for Heat transfer (HEI) formula;
wherein, the HEI formula is as follows:
Figure 318303DEST_PATH_IMAGE005
in the above formula, the first and second carbon atoms are,K 0 is the basic heat transfer coefficient and has the unit of W/(m) 2 Looking up a table according to the outer diameter of the cooling pipe and the circulating water flow speed;β c the coefficient of fouling of the cooling surface of the condenser;β m checking a table according to the pipe and the wall thickness to obtain a constant for the pipe and the wall thickness correction coefficient of the cooling pipe;β t the correction coefficient is obtained by looking up a table according to the inlet water temperature of the circulating water;Kthe unit is W/(m) for the actual total heat transfer coefficient of the condenser 2 ·℃）；
The calculation formula for obtaining the reference fouling coefficient is as follows:
Figure DEST_PATH_IMAGE006
in the above formula, the first and second carbon atoms are,Kthe unit is W/(m) for the actual total heat transfer coefficient of the condenser 2 ·℃）；K 0 Is the basic heat transfer coefficient and has the unit of W/(m) 2 Looking up a table according to the outer diameter of the cooling pipe and the circulating water flow speed;β m looking up a table according to the pipe and the wall thickness to obtain a constant for the pipe and the wall thickness correction coefficient of the cooling pipe;β t the correction coefficient is obtained by looking up a table according to the inlet water temperature of the circulating water;β c the coefficient of fouling of the cooling surface of the condenser;
step 104, calculating the pressure of a condenser:
step 10401, calculating a temperature difference delta between the circulating water inlet and the circulating water outlet of the condenser according to the heat balance relation of the condensertThe unit is ℃:
Figure 25097DEST_PATH_IMAGE007
in the above formula,. DELTA.hThe enthalpy difference of the exhaust steam in the condensing process of the condenser is expressed in kJ/kg;c p is the constant pressure specific heat of water, and the unit is kJ/(kg DEG C);D w is the flow rate of circulating water, and the unit is kg/s;D k the unit is kg/s for the flow of the dead steam;
step 10402, calculating a condenser end difference according to the condenser heat balance relationδtThe unit is ℃:
Figure DEST_PATH_IMAGE008
in the above formula,. DELTA.tThe temperature difference between the circulating water inlet and the circulating water outlet of the condenser is measured in units of temperature;c p the specific heat at constant pressure of water is expressed in kJ/(kg DEG C);D w is the flow rate of circulating water, and the unit is kg/s;δtthe unit is the end difference of a condenser; here, theKIs the overall heat transfer coefficient of the condenser and has the unit of W/(m) 2 C) of whichAIs the heat exchange area of the condenser, and the unit is m 2 ；
Step 10403, calculating the saturation temperature of the condensert s The unit is ℃:
Figure 869163DEST_PATH_IMAGE009
in the above-mentioned formula, the compound has the following structure,t w in, the temperature of a circulating water inlet of a condenser is measured in units of temperature; deltatThe temperature difference between the circulating water inlet and the circulating water outlet of the condenser is measured in units of temperature;δtthe unit is the end difference of a condenser;
step 10404, calculating condenser pressure according to IAPWS-IF1997 formulap cc In kPa:
Figure DEST_PATH_IMAGE010
in the above formula, the first and second carbon atoms are,t s the saturation temperature of the condenser is shown in unit;
step 105, judging that the condenser calculates the condenser pressurep cc And operating pressurep c Deviation betweenδWhether the requirements, deviations, are metδExpressed as:
Figure 472052DEST_PATH_IMAGE011
in the above formula, the first and second carbon atoms are,p cc the pressure of the condenser is used as the pressure of the condenser,p c is the operating pressure; if it is not
Figure DEST_PATH_IMAGE012
Then deviation is determinedδIf the requirements are not met, executing step 106; if it is not
Figure 519511DEST_PATH_IMAGE013
Then deviation is determinedδIf the requirement is met, executing step 107;
step 106, updating the pollution coefficient:
if it is notδ<0, thenβ cbUpdating =β cb -0.001; if it is notδ>0, thenβ cbUpdating =β cb +0.001；β cb In order to update the pre-soiling factor,β cbupdating Is the updated fouling coefficient; returning to execute the step 104 to the step 105, and recalculating the condenser pressure;
step 107, correcting the pollution coefficient calculated by the pollution coefficient calculating module (403)β cx Judging whether to clean the condenser or not as a judgment basis for judging whether to clean the condenser or not;
step 10701, correcting the fouling factorβ cx Calculating the average deviation between the end difference and the operating end difference of the condenserδ δtAverage Expressed as:
Figure DEST_PATH_IMAGE014
in the above formula, the first and second carbon atoms are,δ δt the deviation calculated for the end difference is expressed as:
Figure 702099DEST_PATH_IMAGE015
in the above formula, the first and second carbon atoms are,δ tx the calculated value of the end difference is obtained,δ ty is the running end difference value;
step 10702, setting a boundary value for cleaning the condenser; if it is notβ cx <If the boundary value is the boundary value, judging that the condenser needs to be cleaned, and giving a prompt for cleaning the condenser by a foreground display module (405); if it is notβ cx And if the temperature is more than or equal to the boundary value, judging that the condenser does not need to be cleaned and prompting.
2. The method for monitoring the condenser fouling coefficient online monitoring system according to claim 1, wherein the step 102 specifically comprises the following steps:
step 10201, judging the running state of the unit by the data preprocessing module (402) to judge whether the unit stopsMachine: if the unit loadQ<=aThen judging the unit is stopped, whereinaIs a positive number less than or equal to 5, and has a unit of MW; if circulating water flowV w <=bIf so, judging that the unit is stopped;bis a positive number less than or equal to 10, and the unit is kg/s; if there are more circulating water pumps, the current of each circulating water pumpI<=cJudging that the unit is stopped; whereincIs a positive number less than or equal to 5 and has a unit of A; if the unit stops, the data preprocessing module (402) sends the result to the data storage module (404) and feeds the result back to the foreground display module (405) for display;
step 10202, the real-time operation data is subjected to range judgment, firstly, the high-low range of each real-time operation data is set, then, each real-time operation data and the corresponding high-low range are respectively compared, if the real-time operation data is not in the range, the judgment is over-limit, the data preprocessing module (402) sends the result to the data storage module (404) and feeds alarm information back to the foreground display module (405) for display;
step 10203, carrying out rationality judgment on the real-time operation data, if the temperature of a circulating water outlet of the condenser is less than or equal to the temperature of a circulating water inlet of the condenser, or the end difference of the condenser is less than or equal to 0, or the pressure of the circulating water outlet of the condenser is more than or equal to the pressure of the circulating water inlet of the condenser, judging that the data is unreasonable, and sending the result to a data storage module (404) by a data preprocessing module (402) and feeding the result back to a foreground display module (405) for display;
step 10204, for the data using double or multiple measuring points, carrying out arithmetic mean on the measuring point data, and taking the arithmetic mean as the final value of the measuring point.
3. The monitoring method of the condenser fouling coefficient on-line monitoring system according to claim 1, characterized in that: the real-time operation data in step 101 includes: the system comprises a unit load, condenser circulating water inlet and outlet temperature, condenser circulating water inlet and outlet pressure, condenser end difference, circulating water pump current, circulating water pump voltage, circulating water flow, main hot steam pressure, main hot steam temperature, reheat steam pressure, reheat steam temperature, steam extraction pressure, steam extraction temperature, heater water inlet temperature, heater water outlet temperature, heater drainage temperature, main steam flow, water supply flow, condensate flow, attemperation water flow and external steam supply flow.
4. The utility model provides an online monitoring system of dirty coefficient of condenser which characterized in that includes: the system comprises a real-time operation data acquisition module (401), a data preprocessing module (402), a contamination coefficient calculation module (403), a data storage module (404) and a foreground display module (405); the real-time operation data acquisition module (401) is connected with the data storage module (404) and the data preprocessing module (402); the data preprocessing module (402) is connected with the contamination coefficient calculating module (403), the data storage module (404) and the foreground display module (405); the contamination coefficient calculation module (403) is connected with the data storage module (404) and the foreground display module (405); the condenser fouling factor online monitoring system executes the monitoring method according to any one of claims 1 to 3.
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