CN111855547B - Visual intelligent monitoring system and method for ash deposition corrosion wear state of medium-low temperature flue gas heat exchange equipment - Google Patents
Visual intelligent monitoring system and method for ash deposition corrosion wear state of medium-low temperature flue gas heat exchange equipment Download PDFInfo
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Abstract
A visual intelligent monitoring system and method for the ash deposition corrosive wear state of medium and low temperature smoke and wind heat exchange equipment is characterized in that the actual smoke and wind is adopted, the actual operation working condition is fitted, the smoke inlet temperature and wind speed can be adjusted, the working conditions of different smoke temperature and flow speed of the whole smoke and wind system are simulated, and online monitoring data are provided; the resistance probe and the eddy current sensor are used for monitoring the conditions of heat exchange, corrosion resistance, wear resistance, dust deposition, coking and the like of the heat exchange tube; based on a convolution neural network and an intelligent recognition and analysis model of a monitoring probe state image, an image data set is manufactured by using a large number of field pictures of the monitoring probe and the calculated heat transfer coefficient, dust deposition thermal resistance, corrosion rate and wear rate, so that the state of the image is accurately matched with that of the heat exchange tube; the intelligent recognition and analysis model adopts a convolutional neural network algorithm model to perform pixel-level processing on the image, so that the state image characteristics are accurately recognized, and the accuracy of an analysis result is high; and (4) analyzing the heat transfer coefficient, the ash deposition thermal resistance, the corrosion rate and the wear rate of the heat exchange tube by images.
Description
Technical Field
The invention relates to the technical field of flue gas waste heat recycling, in particular to a visual intelligent monitoring system and a visual intelligent monitoring method for the ash deposition corrosion wear state of medium-low temperature flue gas and air heat exchange equipment. The method is particularly suitable for on-line monitoring of the flue gas heat exchange system of the flue gas heat exchanger of the power plant.
Background
In the prior art, the atmospheric pollution caused by coal burning is increasingly serious, and the acid rain area is continuously enlarged. Removing SO generated during coal combustion 2 In addition, small amounts of SO are also formed 3 、NO X Gases such as HCL and HF contain water vapor in the flue gas, so that H can be formed instantly 2 SO 4 Strongly corrosive solutions such as HCL, HF, etc. Meanwhile, smoke containing smoke dust passes through equipment and pipelines at high speed, and the corrosion and the abrasion to the device are serious. It can be seen that the flue gas heat exchanger is in operation in a harsh environment of highly corrosive media, hot and humid conditions and high wear. Particle deposits on the surface of the flue gas heat exchanger can increase thermal resistance, reduce heat transfer efficiency and increase instability of equipment operation. Because the operation environment is severe, the requirements of the flue gas heat exchanger on corrosion resistance, abrasion resistance and scale inhibition of materials are very strict. The selection of the material of the flue gas heat exchange pipe or the protective material greatly affects the service life and the cost of the device, so that the development of a novel corrosion-resistant, wear-resistant and scale-inhibiting heat exchanger is very important.
In order to research the performance of the flue gas heat exchanger in a flue gas and air system, three general research methods exist at present: (1) The performance monitoring is directly carried out in the actual environment, the method greatly increases the experimental period and cannot be stopped in the operation process, and the normal production operation can be influenced in the experimental process; (2) The method has the advantages that the experiment table is built to simulate the actual working conditions of the flue gas-air system and the heat exchanger, the actual operating conditions of the heat exchanger cannot be completely simulated by the method, and errors can be generated in the experiment result; (3) A bypass is added to a smoke and air system, a monitoring platform is built in the bypass, and the heat exchanger is monitored and analyzed by utilizing the actual smoke and air on site.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to provide a visualized intelligent monitoring system for the dust deposition corrosion wear state of medium and low temperature flue gas heat exchange equipment, which has the advantages of reasonable structure, high automation degree and low cost, can carry out online visualized intelligent monitoring on the dust deposition corrosion wear state of the heat exchange equipment and accurately monitor the dust deposition corrosion wear state of the medium and low temperature flue gas heat exchange equipment, and provides a visualized intelligent monitoring method for the dust deposition corrosion wear state of the medium and low temperature flue gas heat exchange equipment, which is scientific, reasonable, strong in applicability and good in effect.
One of the technical schemes adopted for realizing the purpose of the invention is as follows: the utility model provides a visual intelligent monitoring system of well low temperature flue gas heat exchange equipment deposition corrosive wear state which characterized by includes: the bottom of the boiler 1 is connected with a blower 2, and the top of the boiler 1 is connected with a chimney 4 through a flue gas treatment device 3 arranged on a flue 22; a cooling sleeve 23 is wound on the outer wall of an air inlet section of a bypass flue 38 connected with a flue 22, a water inlet of the cooling sleeve 23 is sequentially connected with a cooling sleeve flowmeter 30, a second variable frequency water pump 10 and a cold water tank 9, a water outlet of the cooling sleeve 23 is connected with a hot water tank 26, the cold water tank 9 is sequentially connected with a third variable frequency water pump 36, a refrigerator 11 and the hot water tank 26, a heat insulation layer 15 is wrapped on the outer wall of the bypass flue 38, an ash-proof baffle 16 is arranged on the inner wall of an expansion section of the bypass flue 38, an observation chamber 12 is arranged below the ash-proof baffle 16, and an outlet of the bypass flue 38 is sequentially connected with an air blower 25 and the flue 22; a CCD camera 13 is arranged at a position where the port of the observation chamber 12 is spaced, the output end of the CCD camera 13 is electrically connected with the upper computer 14, and a cooling fan 27 is arranged at a position where the port of the observation chamber 12 is spaced from the CCD camera 13; a monitoring probe 5 is arranged at the expansion section of the bypass flue 38 and on the opposite side of the observation chamber 12, an acquisition rod 6 connected with the monitoring probe 5 is arranged on the slide rail bracket 20, the water outlet of the acquisition rod 6 is connected with the water inlet of the hot water tank 26, the water outlet of the hot water tank 26 is sequentially connected with the refrigerator 11, the third variable frequency water pump 36 and the water inlet of the cold water tank 9, and the water outlet of the cold water tank 9 is sequentially connected with the first variable frequency water pump 7, the water inlet flowmeter 31, the water inlet thermometer 32 and the water inlet of the acquisition rod 6; the air inlet thermometer 17 is arranged at an air inlet of the bypass flue 38, the air outlet thermometer 24 is arranged at an air outlet of the bypass flue 38, the air inlet thermometer 17 is electrically connected with the air outlet thermometer 24 and the input end of the flue gas temperature acquisition card 33, and the output end of the flue gas temperature acquisition card 33 is electrically connected with the upper computer 14; one end of the flue gas flowmeter 29 is arranged in the bypass flue 38, the output ends of the flue gas flowmeter 29, the cooling sleeve flowmeter 30 and the water inlet flowmeter 31 are electrically connected with the input end of the flow acquisition card 34, the output end of the flow acquisition card 34 is electrically connected with the upper computer 14, the water outlet thermometer 37 connected with the hot water tank 26 is arranged at the water outlet of the soot deposition rod 6, the temperature sensor 39 is arranged on the outer wall of the monitoring probe 5, the output ends of the water inlet thermometer 32, the water outlet thermometer 37 and the temperature sensor 39 are electrically connected with the input end of the temperature acquisition card 35, and the output end of the temperature acquisition card 35 is electrically connected with the upper computer 14; the resistance probe 28 is arranged on the outer wall of the monitoring probe 5, the resistance probe 28 is electrically connected with the corrosion monitor 21, and the output end of the corrosion monitor 21 is electrically connected with the upper computer 14; the eddy current sensor 18 is arranged above the observation chamber 12, and the output end of the eddy current sensor 18 is electrically connected with the eddy current data acquisition card 8 and the upper computer 14 in sequence; the first variable frequency water pump 7, the second variable frequency water pump 10 and the third variable frequency water pump 36 are all electrically connected with the upper computer 14.
The second technical scheme adopted for realizing the purpose of the invention is as follows: a visual intelligent monitoring method for the ash deposition corrosive wear state of medium and low temperature flue gas heat exchange equipment is characterized by comprising the following steps: it comprises the following contents:
1) According to the heat balance principle, the heat exchange quantity of the heat exchange tube is equal to the heat absorption quantity of cooling water in the heat exchange tube and the heat release quantity of smoke, and the heat balance equation is as follows:
Q e ＝Q w ＝Q g (1)
Q g ＝ρ g v g sC p,g (T 1 -T 2 ) (2)
Q w ＝ρ w q w C p,w (t 1 -t 2 ) (3)
in the formula: q e For monitoring the heat exchange capacity of the probe, Q g For the heat exchange quantity of the flue gas side, Q w For heat exchange on the water side, C p,g Is the specific heat capacity of the flue gas, C p,w Is the specific heat capacity of water, p g Is the density of the smoke, v g Is the flue gas wind speed, s is the frontal area, ρ w Is the density of water, q w Is the volume flow rate of water, T 1 Is the temperature of the flue gas inlet, T 2 Is the flue gas outlet temperature, t 1 Is the water inlet temperature, t 2 Is the water outlet temperature;
heat transfer capacity Q in the calculated coefficient of total heat transfer ave Based on the heat exchange quantity Q of the flue gas side g Heat exchange quantity Q of water side w Is determined by the average value of (a),
heat transfer capacity Q ave ：
Q ave ＝(Q g +Q w )/2 (4)
The heat transfer coefficient calculation formula of the monitoring probe is as follows:
in the formula: a. The 0 Is the total heat exchange area, Δ T m Is the logarithmic mean temperature difference;
logarithmic mean temperature difference Δ T m ：
ΔT max ＝T 1 -t 2 (7)
ΔT min ＝T 2 -t 1 (8)
Only the temperature T of the flue gas inlet needs to be measured 1 Temperature T of flue gas outlet 2 Water inlet temperature t 1 And outlet temperature t 2 The heat transfer coefficient K before and after the dust deposition of the monitoring probe can be obtained;
thermal resistance of deposited dust R f ：
In the formula: k is 0 The heat transfer coefficient before the dust deposition of the monitoring probe is shown, and K is the heat transfer coefficient after the dust deposition of the monitoring probe;
using rate of change of heat transfer coefficient
The degree of weakening of the scale to describe the effect of scale on heat transfer properties, the rate of change of the heat transfer coefficient
Comprises the following steps:
calculating the heat transfer coefficient and the dust deposition thermal resistance value of the monitoring probe in the state by the joint type (1) to formula (10);
2) The resistance probe obtains the corrosion rate of the monitoring probe according to the linear relation between the sectional area of the probe and the resistance, the sectional area of a metal material with a certain length is reduced after corrosion thinning, the resistance value is increased, the thinning amount can be calculated as long as the change value of the resistance is known, and for the filiform probe, the calculation formula of the corrosion thinning amount H is as follows:
in the formula: r is 0 Is the original radius of the resistance probe tip, R 0 Is a pre-corrosion resistance value, R t Resistance value after corrosion;
the corrosion rate calculation formula is:
in the formula: t is 2 -T 1 For measuring the time interval twice, H 2 -H 1 Is the difference of two measurements;
calculating the corrosion rate of the monitoring probe in the state by the joint formula (11) to formula (12);
3) According to kirchhoff's law, the loop equation of the eddy current sensor is as follows:
R 1 I 1 +jωL 1 I 1 -jωMI 2 ＝0 (13)
-jωMI 1 +R 2 I 2 +jωL 2 I 2 ＝0 (14)
the equivalent impedance of the coil after being affected by the eddy current is:
function of coil impedance Z:
Z＝f(ρ,x,μ,f) (16)
in the formula: ρ is the resistivity of the metal conductor, μ is the permeability of the metal conductor, x is the distance between the coil and the metal conductor, and f is the frequency of the coil excitation current;
the eddy current thickness measurement formula is as follows:
d＝x-(x 1 +x 2 ) (17)
in the formula: (x) 1 +x 2 ) Is the thickness deviation;
the wear rate calculation formula is:
in the formula: v is the wear volume of the metal conductor, and Sigma W is the accumulated friction work;
calculating the wear rate of the monitoring probe in the state through the joint type (13) -formula (18);
4) Acquiring a monitoring probe state image through a CCD camera, taking the monitoring probe state image as an input quantity, taking the monitoring probe dust deposition thermal resistance, the corrosion rate and the wear rate as target quantities, and establishing an intelligent identification and analysis model based on a convolutional neural network and the monitoring probe state image; adopting images output by a CCD camera at certain time intervals and the calculated heat transfer coefficient, the calculated dust deposition thermal resistance, the calculated corrosion rate and the calculated wear rate of the monitoring probe at the same time to manufacture an image data set; calling an image recognition model based on a convolutional neural network, and training the image recognition model by using an image data set to recognize monitoring probe images in different states; and after the image recognition model is trained to be mature, calling the image recognition model to recognize the monitoring probe image acquired on site in real time, and obtaining the dust deposition thermal resistance, the heat transfer coefficient, the corrosion rate and the wear rate of the monitoring probe according to the output result of the image recognition model.
The invention relates to a visual intelligent monitoring system and method for the ash deposition, corrosion and wear state of medium-low temperature flue gas and air heat exchange equipment, which has the advantages that:
1. the bypass flue is arranged on the flue of the on-site smoke wind system, a cooling sleeve for adjusting smoke inlet temperature is arranged at a smoke inlet of the bypass flue, so that the smoke inlet temperature can be adjusted within the range of 50-300 ℃, and the smoke speed in the bypass flue can be adjusted within the range of 2-12 m/s by changing the power of the air feeder; the temperature of the outer wall of the monitoring probe can be adjusted by changing the temperature of the water inlet of the collecting rod through the refrigerator, the monitoring platform is built on the bypass flue, the heat exchanger is monitored and analyzed by utilizing on-site actual smoke and wind, the actual operation working condition is fitted, and the experimental error is reduced;
2. the method for adjusting the smoke inlet temperature and the wind speed is adopted to simulate the working conditions of different smoke temperatures and flow rates of the whole smoke and wind system, and online monitoring data can be provided for the development of all devices in the smoke and wind system;
3. on the basis of monitoring the heat transfer coefficient and the dust deposition thermal resistance of the heat exchange tube, a resistance probe and an eddy current sensor are added to monitor the corrosion rate and the wear rate of the heat exchange tube, the conditions of the heat exchange performance, the corrosion resistance, the wear resistance, the dust deposition coking and the like of the heat exchange tube are monitored, and accurate monitoring data and comprehensive state analysis are provided for the development of heat exchange equipment;
4. based on the convolution neural network and an intelligent recognition and analysis model of the monitoring probe state image, an image data set is manufactured by using a large number of field pictures of the monitoring probe and the calculated heat transfer coefficient, ash deposition thermal resistance, corrosion rate and wear rate; the accurate matching of the image and the state of the heat exchange tube is realized;
5. the intelligent identification and analysis model based on the convolutional neural network and the monitoring probe state image adopts a convolutional neural network algorithm model to perform pixel-level processing on the image, so that the state image characteristics are accurately identified, and the analysis result is high in accuracy;
6. based on the convolution neural network and an intelligent recognition and analysis model of the monitoring probe state image, the heat transfer coefficient, the ash accumulation thermal resistance, the corrosion rate and the wear rate of the heat exchange tube are analyzed by the image, so that a large amount of monitoring equipment is avoided being additionally arranged on a monitoring platform, the state of the heat exchange tube can be analyzed in real time, the monitoring means is simplified, and the monitoring cost is saved;
7. the device is particularly suitable for on-line monitoring of a smoke-air heat exchange system of a flue gas heat exchanger of a power plant.
Drawings
FIG. 1 is a schematic structural diagram of a visual ash deposition corrosive wear state online monitoring device based on a power plant flue gas and air heat exchange system;
FIG. 2 is an experimental flow chart of a visual ash deposition corrosive wear state online monitoring device based on a power plant flue gas and air heat exchange system;
in the figure: 1-boiler, 2-blower, 3-flue gas treatment device, 4-chimney, 5-monitoring probe, 6-collecting rod, 7-first variable frequency water pump, 8-eddy current data acquisition card, 9-cold water tank, 10-second variable frequency water pump, 11-refrigerator, 12-observation chamber, 13-CCD camera, 14-upper computer, 15-thermal insulation layer, 16-ash-proof baffle, 17-air inlet thermometer, 18-eddy current sensor, 19-sealing plug, 20-slide rack, 21-corrosion monitor, 22-flue, 23-cooling sleeve, 24-air outlet thermometer, 25-blower, 26-hot water tank, 27-cooling fan, 28-resistance probe, 29-flue gas flowmeter, 30-cooling sleeve flowmeter, 31-water inlet flowmeter, 32-water inlet thermometer, 33-flue gas temperature acquisition card, 34-flow acquisition card, 35-temperature acquisition card, 36-third variable frequency water pump, 37-water outlet thermometer, 38-bypass flue, 39-temperature sensor.
Detailed Description
The invention is further described below with reference to the drawings and the detailed description.
Referring to fig. 1, the visualized intelligent monitoring system for the ash deposition corrosion wear state of the medium-low temperature flue gas and air heat exchange equipment comprises: the system comprises a boiler 1, a blower 2, a flue gas treatment device 3, a chimney 4-, a monitoring probe 5, a collection rod 6, a first variable frequency water pump 7, an eddy current data collection card 8, a cold water tank 9, a second variable frequency water pump 10, a refrigerator 11, an observation chamber 12, a CCD camera 13, an upper computer 14, a heat insulation layer 15, an ash-proof baffle 16, an air inlet thermometer 17, an eddy current sensor 18, a sealing plug 19, a slide rail bracket 20, a corrosion monitor 21, a flue 22, a cooling sleeve 23, an air outlet thermometer 24, a blower 25, a hot water tank 26, a cooling fan 27, a resistance probe 28, a flue gas flowmeter 29, a cooling sleeve flowmeter 30, a water inlet flowmeter 31, a water inlet thermometer 32, a flue gas temperature collection card 33, a flow collection card 34, a temperature collection card 35, a third variable frequency water pump 36, a water outlet 37, a flue bypass 38 and a temperature sensor 39. The bottom of the boiler 1 is connected with a blower 2, and the top of the boiler 1 is connected with a chimney 4 through a flue gas treatment device 3 arranged on a flue 22; a cooling sleeve 23 is wound on the outer wall of an air inlet section of a bypass flue 38 connected with a flue 22, a water inlet of the cooling sleeve 23 is sequentially connected with a cooling sleeve flowmeter 30, a second variable frequency water pump 10 and a cold water tank 9, a water outlet of the cooling sleeve 23 is connected with a hot water tank 26, the cold water tank 9 is sequentially connected with a third variable frequency water pump 36, a refrigerator 11 and the hot water tank 26, a heat insulation layer 15 is wrapped on the outer wall of the bypass flue 38, an ash-proof baffle 16 is arranged on the inner wall of an expansion section of the bypass flue 38, an observation chamber 12 is arranged below the ash-proof baffle 16, and an outlet of the bypass flue 38 is sequentially connected with an air blower 25 and the flue 22; a CCD camera 13 is arranged at the position where the port of the observation chamber 12 is at a distance, the output end of the CCD camera 13 is electrically connected with the upper computer 14, and a cooling fan 27 is arranged at the position where the port of the observation chamber 12 is at a distance with the CCD camera 13; a monitoring probe 5 is arranged at the capacity expansion section of the bypass flue 38 and on the opposite side of the observation chamber 12, a collecting rod 6 connected with the monitoring probe 5 is arranged on the slide rail bracket 20, the water outlet of the collecting rod 6 is connected with the water inlet of the hot water tank 26, the water outlet of the hot water tank 26 is sequentially connected with the refrigerator 11, the third variable frequency water pump 36 and the water inlet of the cold water tank 9, and the water outlet of the cold water tank 9 is sequentially connected with the first variable frequency water pump 7, the water inlet flowmeter 31, the water inlet thermometer 32 and the water inlet of the collecting rod 6; the air inlet thermometer 17 is arranged at an air inlet of the bypass flue 38, the air outlet thermometer 24 is arranged at an air outlet of the bypass flue 38, the air inlet thermometer 17 is electrically connected with the air outlet thermometer 24 and the input end of the flue gas temperature acquisition card 33, and the output end of the flue gas temperature acquisition card 33 is electrically connected with the upper computer 14; one end of the flue gas flowmeter 29 is arranged in the bypass flue 38, the output ends of the flue gas flowmeter 29, the cooling sleeve flowmeter 30 and the water inlet flowmeter 31 are electrically connected with the input end of the flow acquisition card 34, the output end of the flow acquisition card 34 is electrically connected with the upper computer 14, the water outlet thermometer 37 connected with the hot water tank 26 is arranged at the water outlet of the soot deposition rod 6, the temperature sensor 39 is arranged on the outer wall of the monitoring probe 5, the output ends of the water inlet thermometer 32, the water outlet thermometer 37 and the temperature sensor 39 are electrically connected with the input end of the temperature acquisition card 35, and the output end of the temperature acquisition card 35 is electrically connected with the upper computer 14; the resistance probe 28 is arranged on the outer wall of the monitoring probe 5, the resistance probe 28 is electrically connected with the corrosion monitor 21, and the output end of the corrosion monitor 21 is electrically connected with the upper computer 14; the eddy current sensor 18 is arranged above the observation chamber 12, and the output end of the eddy current sensor 18 is electrically connected with the eddy current data acquisition card 8 and the upper computer 14 in sequence; the first variable frequency water pump 7, the second variable frequency water pump 10 and the third variable frequency water pump 36 are all electrically connected with the upper computer 14. A flue bypass 38 is arranged on the flue 22, a cooling sleeve 23 is arranged at a smoke inlet of the flue bypass 38 to adjust the smoke inlet temperature, so that the smoke inlet temperature can be adjusted within the range of 50-300 ℃, and the smoke speed in the flue bypass 38 can be adjusted within the range of 2-12 m/s by the blower 2 through changing the power; the temperature of the outer wall of the monitoring probe 5 can be adjusted by changing the temperature of the water inlet of the acquisition rod 6 by using the refrigerator 11.
Referring to fig. 1 and fig. 2, the visualized intelligent monitoring method for the ash deposition corrosion wear state of the medium and low temperature flue gas heat exchange equipment comprises the following contents:
1) According to the heat balance principle, the heat exchange quantity of the heat exchange tube is equal to the heat absorption quantity of cooling water in the heat exchange tube and the heat release quantity of smoke, and the heat balance equation is as follows:
Q e ＝Q w ＝Q g (1)
Q g ＝ρ g v g sC p,g (T 1 -T 2 ) (2)
Q w ＝ρ w q w C p,w (t 1 -t 2 ) (3)
in the formula: q e For monitoring the heat exchange capacity of the probe, Q g For the heat exchange quantity on the flue gas side, Q w The amount of heat exchange on the water side, C p,g Is the specific heat capacity of the flue gas, C p,w Is the specific heat capacity of water, ρ g Is the density of the smoke, v g Is the flue gas wind speed, s is the frontal area, ρ w Is the density of water, q w Is the volume flow rate of water, T 1 Is the inlet temperature of the flue gas, T 2 Is the flue gas outlet temperature, t 1 Is the water inlet temperature, t 2 Is the water outlet temperature;
heat transfer capacity Q in the calculated coefficient of total heat transfer ave Based on the heat exchange quantity Q of the flue gas side g Heat exchange quantity Q of water side w Is determined by the average value of (a) of (b),
heat transfer capacity Q ave ：
Q ave ＝(Q g +Q w )/2 (4)
The heat transfer coefficient calculation formula of the monitoring probe is as follows:
in the formula: a. The 0 Is the total heat exchange area, Δ T m Is the log mean temperature difference;
logarithmic mean temperature difference Δ T m ：
ΔT max ＝T 1 -t 2 (7)
ΔT min ＝T 2 -t 1 (8)
Only the temperature T of the flue gas inlet is measured 1 Temperature T of flue gas outlet 2 Temperature t of water inlet 1 And outlet temperature t 2 I.e. before and after deposition of the monitoring probeA heat transfer coefficient K;
thermal resistance of deposited dust R f ：
In the formula: k 0 The heat transfer coefficient of the monitoring probe before dust deposition is measured, and K is the heat transfer coefficient of the monitoring probe after dust deposition;
using rate of change of heat transfer coefficient
The degree of weakening of the scale to describe the effect of scale on heat transfer properties, the rate of change of the heat transfer coefficient
Comprises the following steps:
calculating the heat transfer coefficient and the dust deposition thermal resistance value of the monitoring probe in the state by the joint formula (1) to the formula (10);
2) The resistance probe obtains the corrosion rate of the monitoring probe according to the linear relation between the sectional area of the probe and the resistance, the sectional area of a metal material with a certain length is reduced after corrosion thinning, the resistance value is increased, the thinning amount can be calculated as long as the change value of the resistance is known, and for the filiform probe, the calculation formula of the corrosion thinning amount H is as follows:
in the formula: r is 0 Is the original radius of the resistance probe tip, R 0 Is a pre-corrosion resistance value, R t Resistance value after corrosion;
the corrosion rate calculation formula is:
in the formula: t is a unit of 2 -T 1 For measuring the time interval twice, H 2 -H 1 Is the difference of two measurements;
calculating the corrosion rate of the monitoring probe in the state by the joint formula (11) to formula (12);
3) According to kirchhoff's law, the loop equation of the eddy current sensor is as follows:
R 1 I 1 +jωL 1 I 1 -jωMI 2 ＝0 (13)
-jωMI 1 +R 2 I 2 +jωL 2 I 2 ＝0 (14)
the equivalent impedance of the coil after being affected by the eddy current is:
function of coil impedance Z:
Z＝f(ρ,x,μ,f) (16)
in the formula: ρ is the resistivity of the metal conductor, μ is the permeability of the metal conductor, x is the distance between the coil and the metal conductor, and f is the frequency of the coil excitation current;
the eddy current thickness measurement formula is as follows:
d＝x-(x 1 +x 2 ) (17)
in the formula: (x) 1 +x 2 ) Is the thickness deviation;
the wear rate calculation formula is:
in the formula: v is the wear volume of the metal conductor, and Sigma W is the accumulated friction work;
calculating the wear rate of the monitoring probe in the state by the joint formula (13) to formula (18);
4) Acquiring a monitoring probe state image through a CCD camera, taking the monitoring probe state image as an input quantity, taking the monitoring probe dust deposition thermal resistance, the corrosion rate and the wear rate as target quantities, and establishing an intelligent identification and analysis model based on a convolutional neural network and the monitoring probe state image; adopting images output by a CCD camera at certain time intervals and the calculated heat transfer coefficient, the calculated dust deposition thermal resistance, the calculated corrosion rate and the calculated wear rate of the monitoring probe at the same time to manufacture an image data set; calling an image recognition model based on a convolutional neural network, and training the image recognition model by using an image data set to recognize monitoring probe images in different states; and after the image recognition model is trained to be mature, calling the image recognition model to recognize the monitoring probe image acquired in real time on site, and obtaining the dust deposition thermal resistance, the heat transfer coefficient, the corrosion rate and the wear rate of the monitoring probe according to the output result of the image recognition model.
The invention relates to a visual intelligent monitoring system and a method for the dust deposition corrosion wear state of medium-low temperature smoke-wind heat exchange equipment, which adopts actual smoke wind, fits the actual operation working condition, reduces experimental errors, can adjust smoke inlet temperature and wind speed, simulates the working conditions of different smoke temperatures and flow rates of the whole smoke-wind system, can provide online monitoring data for the development of all devices in the smoke-wind system, adds a resistance probe and an eddy current sensor on the basis of monitoring the heat transfer coefficient and dust deposition thermal resistance of a heat exchange tube to monitor the corrosion rate and wear rate of the heat exchange tube, monitors the heat exchange performance, corrosion resistance, wear resistance, dust deposition coking and other conditions of the heat exchange tube, provides accurate monitoring data and comprehensive state analysis for the development of the heat exchange equipment, and manufactures an image data set by using a large number of field pictures of monitoring probes and calculated heat transfer coefficient, dust deposition thermal resistance, corrosion rate and wear rate based on an intelligent identification and analysis model of a convolution neural network and monitoring probe state image, thereby realizing the accurate matching of the image and the heat exchange tube state; the intelligent recognition and analysis model adopts a convolutional neural network algorithm model to perform pixel-level processing on the image, accurately recognizes the state image characteristics, has high accuracy of analysis results, analyzes the heat transfer coefficient, the dust-deposition thermal resistance, the corrosion rate and the wear rate of the heat exchange tube by the image, avoids adding a large amount of monitoring equipment on a monitoring platform, can analyze the state of the heat exchange tube in real time, simplifies the monitoring means and saves the monitoring cost.
The elements and devices used in the invention are all commercial products, and are easy to implement. The control program according to the present invention is programmed based on an automatic control technique and a computer processing technique, and is a technique familiar to those skilled in the art.
While the present invention has been described with reference to particular embodiments, it is not intended to be limited to the embodiments but is intended to cover modifications that are obvious to those skilled in the art, given the benefit of the teachings herein.
Claims (2)
1. The utility model provides a visual intelligent monitoring system of well low temperature flue gas indirect heating equipment deposition corrosive wear state which characterized in that, it includes: the bottom of the boiler (1) is connected with the blower (2), and the top of the boiler (1) is connected with the chimney (4) through a flue gas treatment device (3) arranged on the flue (22); a cooling sleeve (23) is wound on the outer wall of an air inlet section of a bypass flue (38) connected with a flue (22), a water inlet of the cooling sleeve (23) is sequentially connected with a cooling sleeve flowmeter (30), a second variable frequency water pump (10) and a cold water tank (9), a water outlet of the cooling sleeve (23) is connected with a hot water tank (26), the cold water tank (9) is sequentially connected with a third variable frequency water pump (36), a refrigerator (11) and the hot water tank (26), an ash-proof baffle (16) is arranged on the inner wall of an expansion section of the bypass flue (38), an observation chamber (12) is arranged below the ash-proof baffle (16), and an outlet of the bypass flue (38) is sequentially connected with an air blower (25) and the flue (22); a CCD camera (13) is arranged at a position where a port of the observation chamber (12) is spaced, the output end of the CCD camera (13) is electrically connected with an upper computer (14), and a cooling fan (27) is arranged at a position where the port of the observation chamber (12) is spaced from the CCD camera (13); a monitoring probe (5) is arranged at the capacity expansion section of the bypass flue (38) and on the opposite side of the observation chamber (12), an acquisition rod (6) connected with the monitoring probe (5) is arranged on the slide rail bracket (20), the water outlet of the acquisition rod (6) is connected with the water inlet of the hot water tank (26), the water outlet of the hot water tank (26) is sequentially connected with the refrigerating machine (11), the third variable frequency water pump (36) and the water inlet of the cold water tank (9), and the water outlet of the cold water tank (9) is sequentially connected with the first variable frequency water pump (7), the water inlet flowmeter (31), the water inlet thermometer (32) and the water inlet of the acquisition rod (6); the air inlet thermometer (17) is arranged at an air inlet of the bypass flue (38), the air outlet thermometer (24) is arranged at an air outlet of the bypass flue (38), the air inlet thermometer (17) is electrically connected with the air outlet thermometer (24) and the input end of the flue gas temperature acquisition card (33), and the output end of the flue gas temperature acquisition card (33) is electrically connected with the upper computer (14); one end of a flue gas flowmeter (29) is arranged in a bypass flue (38), the output ends of the flue gas flowmeter (29), a cooling sleeve flowmeter (30) and a water inlet flowmeter (31) are electrically connected with the input end of a flow acquisition card (34), the output end of the flow acquisition card (34) is electrically connected with an upper computer (14), a water outlet thermometer (37) connected with a hot water tank (26) is arranged at the water outlet of a dust rod (6), a temperature sensor (39) is arranged on the outer wall of a monitoring probe (5), the output ends of the water inlet thermometer (32), the water outlet thermometer (37) and the temperature sensor (39) are electrically connected with the input end of the temperature acquisition card (35), and the output end of the temperature acquisition card (35) is electrically connected with the upper computer (14); the resistance probe (28) is arranged on the outer wall of the monitoring probe (5), the resistance probe (28) is electrically connected with the corrosion monitor (21), and the output end of the corrosion monitor (21) is electrically connected with the upper computer (14); the eddy current sensor (18) is arranged above the observation chamber (12), and the output end of the eddy current sensor (18) is electrically connected with the eddy current data acquisition card (8) and the upper computer (14) in sequence; the first variable-frequency water pump (7), the second variable-frequency water pump (10) and the third variable-frequency water pump (36) are electrically connected with the upper computer (14); the monitoring method comprises the following steps:
1) According to the heat balance principle, the heat exchange quantity of the heat exchange tube is equal to the heat absorption quantity of cooling water in the heat exchange tube and the heat release quantity of flue gas, and the heat balance equation is as follows:
Q e ＝Q w ＝Q g (1)
Q g ＝ρ g v g sC p,g (T 1 -T 2 ) (2)
Q w ＝ρ w q w C p,w (t 1 -t 2 ) (3)
in the formula: q e For monitoring the heat exchange capacity of the probe, Q g For the heat exchange quantity of the flue gas side, Q w The amount of heat exchange on the water side, C p,g Is the specific heat capacity of the flue gas, C p,w Is the specific heat capacity of water, p g Is the density of the flue gas, v g Is the flue gas wind speed, s is the windward area, ρ w Is the density of water, q w Is the volume flow rate of water, T 1 Is the temperature of the flue gas inlet, T 2 Is the flue gas outlet temperature, t 1 Is the water inlet temperature, t 2 Is the water outlet temperature;
of the calculated coefficients of total heat transfer, the heat transfer capacity Q ave Based on the heat exchange quantity Q of the flue gas side g Heat exchange quantity Q of water side w Is determined by the average value of (a),
heat transfer capacity Q ave ：
Q ave ＝(Q g +Q w )/2 (4)
The calculation formula of the heat transfer coefficient after the monitoring probe is accumulated with dust is as follows:
in the formula: a. The 0 Is the total heat exchange area, Δ T m Is the log mean temperature difference;
logarithmic mean temperature difference Δ T m ：
ΔT max ＝T 1 -t 2 (7)
ΔT min ＝T 2 -t 1 (8)
Only the temperature T of the flue gas inlet is measured 1 Temperature T of flue gas outlet 2 Water inlet temperature t 1 And outlet temperature t 2 Namely, the heat transfer coefficients K of the monitoring probe before and after dust deposition can be obtained;
thermal resistance of deposited dust R f ：
In the formula: k is 0 The heat transfer coefficient before the dust deposition of the monitoring probe is shown, and K is the heat transfer coefficient after the dust deposition of the monitoring probe;
using rate of change of heat transfer coefficient
The degree of weakening of the scale to describe the effect of the scale on the heat transfer performance, the rate of change of the heat transfer coefficient
Comprises the following steps:
calculating the heat transfer coefficient and the dust deposition thermal resistance value of the monitoring probe in the state by the joint formula (1) to the formula (10);
2) The resistance probe obtains the corrosion rate of the monitoring probe according to the linear relation between the sectional area of the probe and the resistance, the sectional area of a metal material with a certain length is reduced after corrosion thinning, the resistance value is increased, the thinning amount can be calculated as long as the change value of the resistance is known, and for the filiform probe, the calculation formula of the corrosion thinning amount H is as follows:
in the formula: r is a radical of hydrogen 0 Is the original radius of the resistance probe tip, R 0 Is a pre-corrosion resistance value, R t Is the resistance value after corrosion;
the corrosion rate calculation formula is:
in the formula tau 2 -τ 1 When two measurements are madeInter space, H 2 -H 1 Is the difference of two measurements;
calculating the corrosion rate of the monitoring probe in the state by the joint formula (11) to formula (12);
3) According to kirchhoff's law, the loop equation of the eddy current sensor is:
R 1 I 1 +jωL 1 I 1 -jωMI 2 ＝0 (13)
-jωMI 1 +R 2 I 2 +jωL 2 I 2 ＝0 (14)
the equivalent impedance of the coil after being affected by the eddy current is:
coil impedance Z c Function of (c):
Z c ＝f(ρ,x,μ,f r ) (16)
in the formula: ρ is the resistivity of the metal conductor, μ is the permeability of the metal conductor, x is the distance between the coil and the metal conductor, f r Is the frequency of the coil excitation current;
the eddy current thickness measurement formula is:
d＝x-(x 1 +x 2 ) (17)
in the formula: (x) 1 +x 2 ) Is the thickness deviation;
the wear rate calculation formula is:
in the formula: v a The volume of the worn metal conductor, and sigma W is accumulated friction work;
calculating the wear rate of the monitoring probe in the state through the joint type (13) -formula (18);
4) Acquiring a monitoring probe state image through a CCD camera, taking the monitoring probe state image as an input quantity, taking the monitoring probe dust deposition thermal resistance, the corrosion rate and the wear rate as target quantities, and establishing an intelligent identification and analysis model based on a convolutional neural network and the monitoring probe state image; adopting images output by a CCD camera at certain time intervals and the calculated heat transfer coefficient, the calculated dust deposition thermal resistance, the calculated corrosion rate and the calculated wear rate of the monitoring probe at the same time to manufacture an image data set; calling an image recognition model based on a convolutional neural network, and training the image recognition model by using an image data set to recognize monitoring probe images in different states; and after the image recognition model is trained to be mature, calling the image recognition model to recognize the monitoring probe image acquired on site in real time, and obtaining the dust deposition thermal resistance, the heat transfer coefficient, the corrosion rate and the wear rate of the monitoring probe according to the output result of the image recognition model.
2. The system for visually and intelligently monitoring the ash deposition, corrosion and wear states of medium and low temperature flue gas heat exchange equipment according to claim 1, wherein a heat insulation layer (15) is wrapped on the outer wall of the bypass flue (38).
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