An ammonium chloride particle deposition property testing device and method

Abstract

The application discloses an experimental device and method suitable for testing deposition of ammonium chloride particles on the wall of a tube bundle, wherein a test section is horizontally arranged, an outlet in an air heating system is connected with a horizontal inlet of the test section, a part of a solution atomization system is arranged inside a vertical inlet of the test section, heat exchange tubes in a heat exchange system are arranged in the middle of the test section, and an outlet of the test section is connected with a waste gas collector; and a shooting system is arranged towards a quartz glass tube of the test section and shoots. By adjusting different gas flow rates, humidity and water temperature, the application can observe the deposition process of crystalline particles on the wall of the heat exchange tubes, analyze the crystalline phase structure and deposition amount of the outer wall of the tube bundle, calculate the deposition layer thickness and deposition rate of the crystalline phase on the wall of the heat exchange tubes under different working conditions, and research the deposition of ammonium chloride crystalline particles in a petrochemical system.

Description

TECHNICAL FIELD

[0001] The present application relates to a device and method for testing deposition on heat exchange tube bundle, in particular to a device and method for testing deposition of ammonium chloride particles on tube bundle wall. BACKGROUND

[0002] Particle deposition is a basic physical process, which plays an important role in many disciplines, such as materials, chemical engineering, aerospace, energy and environmental science, etc. In petrochemical systems, ammonium chloride particles often deposit on the wall of air-cooled tube bundle, causing tube bundle blockage and deposition corrosion problems, which seriously affect the long-term safe operation of cold and hot equipment.

[0003] The related research results at home and abroad are mostly concentrated in the analysis of crystal structure, growth characteristics and influencing factors of saturated aqueous solution, corrosion risk of heat exchanger and prevention and control of particle deposition by water injection, and lack of research on deposition characteristics of ammonium chloride particles. In order to solve the deposition and blockage problem of ammonium chloride particles, it is very important to understand and study the deposition characteristics of ammonium chloride particles on metal surface. SUMMARY

[0004] In view of the deposition and blockage problem of ammonium chloride particles commonly existing in petrochemical industry, the present application provides a device and method for testing deposition characteristics of ammonium chloride particles, which can solve the problems raised in the background art.

[0005] In order to achieve the above purpose, the present application realizes the following technical solutions:

[0006] I. A device for testing deposition characteristics of ammonium chloride particles:

[0007] The device comprises an air heating system, a solution atomization system, a test section, a heat exchange system, a shooting system and a waste gas collector. The test section is horizontally arranged. The outlet of the air heating system is connected to the horizontal inlet of the test section. Part of the solution atomization system is installed inside the vertical inlet of the test section. The heat exchange tube of the heat exchange system is installed in the middle of the test section. The outlet of the test section is connected to the waste gas collector. The shooting system is arranged towards the quartz glass tube of the test section and shoots.

[0008] The air heating system comprises a fan, a controller, an air heater and an air speed meter. The outlet of the fan is connected to the inlet of the air heater. The outlet of the air heater is communicated with one end of the test section. The outlet of the air heater is provided with an air speed meter. The controller for adjusting the temperature of the inlet and outlet of the air heater and the flow rate of the outlet gas is electrically connected with the fan and the air heater, respectively.

[0009] The test section comprises a quartz glass tube, a humidity device, a temperature display and a heat exchange tube, one end of the quartz glass tube is connected with an air heater outlet, the other end is connected with a waste gas collector, a humidity measuring probe connected with the humidity device is installed on the upper part of the quartz glass tube, and the heat exchange tube is installed through the test section, and temperature measuring probes connected with the temperature display are installed on the inner and outer walls of the heat exchange tube in the test section;

[0010] The atomization system comprises a solution atomizer and an atomization nozzle, the solution atomizer stores an ammonium chloride solution, the atomization nozzle is arranged in the quartz glass tube, the atomization nozzle is connected with the solution atomizer outside the quartz glass tube through a pipeline and a corrosion-resistant centrifugal pump, a corrosion-resistant electronic flow meter is arranged on the pipeline between the atomization nozzle and the corrosion-resistant centrifugal pump, and a first valve is arranged on the pipeline between the solution atomizer and the corrosion-resistant centrifugal pump.

[0011] The heat exchange system comprises a water heater and a heat exchange tube, the water heater is arranged outside the test section, one end of the heat exchange tube is connected with one end of the water heater through a water pump and a pipeline, the other end of the water heater is connected with the other end of the heat exchange tube, a thermometer and a flow meter are arranged on the pipeline between the heat exchange tube and the water pump, and a second valve is arranged on the pipeline between the water heater and the water pump.

[0012] The heat exchange tube is arranged in the quartz glass tube in the test section in a slanting manner, the upper end of the heat exchange tube is connected with the outlet end of the water heater through a water pump and a pipeline, and the lower end of the heat exchange tube is connected with the inlet end of the water heater.

[0013] The heat exchange tube is fixed in the quartz glass tube in a slanting manner, water flows in the heat exchange tube, the quartz glass tube contains a gas with a higher temperature than the water, the outer surface of the heat exchange tube is in contact with the hot air in the quartz glass tube, and heat exchange is performed between the water with a lower temperature and the air with a higher temperature.

[0014] The photographing system comprises a microscopic camera and a display, the heat exchange tube in the test section is arranged in the transparent quartz glass tube, the microscopic camera arranged outside the quartz glass tube is arranged to photograph the heat exchange tube in the quartz glass tube, and the microscopic camera and the display are electrically connected.

[0015] The solution atomizer is an ultrasonic atomizer used for atomizing the solution into smaller droplets.

[0016] The air heating system, the atomization system and the heat exchange system simulate the heat exchange environment of high-temperature fluid and low-temperature fluid in a heat exchange device in a petrochemical system and the formation and deposition process of crystalline particles.

[0017] The outer wall of the heat exchange pipe is provided with a center position A1 at any point on the midpoint of the axial direction, and temperature measuring probes are respectively installed at the center position A1 and two positions A2 and A3 on the outer wall of the heat exchange pipe which are 6cm away from the center position A1 along the axial direction, and two positions A4 and A5 on the outer wall of the heat exchange pipe which are 60° away from the center position A1 along the circumferential direction, and temperature measuring probes are respectively installed at the positions A1'-A5' on the inner wall corresponding to the measuring points A1-A5 on the outer wall. in The temperature measuring probe.

[0018] II. A method for testing the deposition characteristics of ammonium chloride particles, the method comprising the following steps:

[0019] Step 1: Turn on the air heating system, turn on the switch of the fan, adjust the air flow speed υ of the outlet of the air heater flow , turn on the switch of the air heater, adjust the controller, set the heating temperature T 加 inside the air heater and the outlet temperature T flow to work;

[0020] Step 2: Turn on the water heater, start heating the water, open the second valve, start the water pump, observe the temperature T 水 on the thermometer, when the temperature T 水 reaches the working temperature, turn off the water heater, open the flowmeter, adjust the opening size of the second valve, observe the water flow value Q 水 on the flowmeter to reach the predetermined working condition;

[0021] Step 3: Observe the outlet temperature T flow of the air heater on the controller, when the outlet temperature T flow reaches the predetermined temperature and is stable, and when the water temperature T 水 and the water flow value Q 水 on the thermometer and the flowmeter are stable, record the stable water temperature and water flow;

[0022] Step 4: After the readings in step 3 are stable, start the atomization system and the microscope, open the first valve, start the corrosion-resistant centrifugal pump, the solution atomizer atomizes the ammonium chloride solution to generate atomized droplets, which are pumped into the atomizing nozzle by the corrosion-resistant centrifugal pump and sprayed out of the quartz glass tube, the atomized droplets sprayed out of the atomizing nozzle evaporate and precipitate crystalline particles in the high-temperature gas in the quartz glass tube, and the formed crystalline particles deposit on the lower-temperature heat exchange pipe to form a deposition layer.

[0023] Adjust the opening size of the first valve to control the atomization flow Q 雾 of the atomized droplets generated by the ammonium chloride solution, observe the corrosion-resistant electronic flowmeter and record the atomization flow Q 雾, open the humidity recorder to record the humidity RH in the quartz glass tube, open the micro camera to shoot the deposition process of the ammonium chloride crystal particles on the heat exchange tube, and start timing;

[0024] Step 5: open the temperature display, and record the temperature T of each measuring point on the inner and outer walls of the tube heat pipe every same time interval in and T out ;

[0025] Step 6: record the deposition time t of each test, and take out the heat exchange tube after each test to weigh the deposition amount m of the crystal particles, calculate the thickness r(t) and deposition rate epsilon(t) of the deposition layer at different positions, and obtain the distribution of the crystal particles in the deposition layer at different positions;

[0026] Step 7: according to the experimental process of steps 1-6, adjust the gas flow rate v flow , the temperature T 水 of the water heater and change the concentration of the solution in the atomizer to change the humidity RH, and test the deposition of the crystal particles under different working conditions.

[0027] During the test, the thickness r(t) of the deposition layer on the surface of the temperature measuring probe on the heat exchange tube at t time is obtained by processing the temperature obtained by measuring the outer and inner walls of the heat exchange tube, the outlet temperature of the air heater according to the following formula:

[0028]

[0029] In the formula, r(t) is the thickness of the deposition layer on the surface at t time, T flow is the outlet temperature of the air heater, T out , T in are the temperatures obtained by measuring the temperature measuring probe on the outer and inner walls of the heat exchange tube, respectively, and R is the thickness between the outer and inner walls of the heat exchange tube; lambda a , lambda w are the thermal conductivities of the deposition layer and the temperature measuring probe, respectively, K represents the heat conduction thickness, K is assumed to be 1 at the beginning of the experiment, and K value is calibrated after preliminary experiment.

[0030] The present application adjusts different gas flow rates, humidities and water temperatures, observes the deposition process of the crystal particles on the wall of the heat exchange tube, analyzes the crystal phase structure and deposition amount of the outer wall of the tube bundle, calculates the deposition layer thickness and deposition rate of the crystal phase on the wall of the heat exchange tube under different working conditions, and studies the deposition problem of the ammonium chloride crystal particles in the petrochemical system.

[0031] The device and method of the present application have the following beneficial effects:

[0032] 1. This invention can experimentally test the deposition process of ammonium chloride particles in petrochemical systems, providing a test basis for establishing critical deposition criteria.

[0033] 2. This invention includes a heating system and an atomization system, used to adjust the different outlet temperatures T of the heated air. flow Gas flow rate υ flow and atomization inlet flow rate Q 雾 Water temperature T 水 Key parameters such as humidity (RH) are adjusted by changing the concentration of the solution in the atomizer to suit simulation experiments of ammonium chloride deposition process under different environments.

[0034] 3. The present invention includes temperature test probes at different locations on the heat exchange tube wall, used to measure the temperature at each temperature measurement point, and the deposition thickness r(t) at different locations at time t can be calculated from the temperature at each point.

[0035] 4. This invention uses a high-temperature resistant transparent quartz glass tube to observe the particle crystallization characteristics and deposition process on the heat exchange equipment under high-temperature conditions using a micro-camera. The deposition thickness r(t) is calibrated by the image deposition thickness change value, providing experimental basis for deposition corrosion prevention and control.

[0036] 5. This invention includes a heat exchange system, wherein the heat exchange tube is a detachable component. By replacing the heat exchange tube, experimental tests can be conducted under different operating conditions. Ammonium chloride particles will be deposited on the wall of the heat exchange tube. Measurements are taken every 10° along the outer circumference of the heat exchange tube, and the amount of crystalline particles deposited at different positions is weighed. This can be used to test the particle deposition pattern at different circumferential angles and calculate the deposition rate ε(t). The microscopic morphology of the weighed deposits can be analyzed to verify the deposition thickness r(t), providing a scientific reference for the safe operation of the equipment. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the overall structure of the device of the present invention;

[0038] Figure 2 for Figure 1 Schematic diagram of the installation position of the temperature measurement probe on the wall of the heat exchange tube in the test section and the deposition thickness r(t); (a) shows the installation position of the axial temperature measurement probe on the heat exchange tube, and (b) shows the deposition thickness on the wall of the heat exchange tube.

[0039] Figure 3 The heat exchange tube surface wall at different locations and with different deposition amounts (m) and gas flow rates (υ) were obtained through pre-testing in this embodiment of the invention. flow The relationship between deposition rate ε(t) and deposition rate is shown in (a) and (b) respectively. (a) represents the deposition amount m at different locations on the heat exchanger tube wall. flow The relationship between the deposition rate ε(t) and the deposition rate ε(t).

[0040] In the diagram: 1. Fan; 2. Controller; 3. Air heater; 4. Anemometer; 5. Quartz glass tube; 6. Atomizer; 7. First valve; 8. Corrosion-resistant centrifugal pump; 9. Corrosion-resistant electronic flow meter; 10. Atomizing nozzle; 11. Humidifier; 12. Humidity measuring probe; 13. Temperature measuring probe; 14. Heat exchange tube; 15. Temperature display; 16. Waste gas collector; 17. Water heater; 18. Second valve; 19. Water pump; 20. Thermometer; 21. Flow meter; 22. Microscope; 23. Display. Detailed Implementation

[0041] The specific implementation of the present invention will be further described with reference to the accompanying drawings.

[0042] like Figure 1 As shown, the device includes an air heating system, a solution atomization system, a test section, a heat exchange system, an imaging system, and an exhaust gas collector. The test section is arranged horizontally. The outlet of the air heating system is connected to the horizontal inlet of the quartz glass tube 5 of the test section. Part of the atomizing nozzle 10 of the solution atomization system is installed inside the vertical inlet of the quartz glass tube 5 of the test section. The heat exchange tube 14 of the heat exchange system is installed in the middle of the quartz glass tube 5 of the test section. The outlet of the quartz glass tube 5 of the test section is connected to the exhaust gas collector 16. The microscope camera 22 connected to the display 23 in the imaging system is positioned towards the heat exchange tube 14 in the quartz glass tube 5 of the test section and takes pictures.

[0043] The air heating system includes a fan 1, a controller 2, an air heater 2, and an anemometer 4. The outlet of the fan 1 is connected to the inlet of the air heater 3, and the outlet of the air heater 3 is connected to one end of the test section. An anemometer 4 is installed at the outlet of the air heater 3. The controller 2, which is used to adjust the inlet and outlet temperatures and the outlet gas flow rate of the air heater 3, is electrically connected to the fan 1 and the air heater 3.

[0044] The test section includes a quartz glass tube 5, a humidifier 11, a temperature display 15, and a heat exchange tube 14. The actual test section uses a quartz glass tube 5. One end of the quartz glass tube 5 is connected to the outlet of the air heater 3, and the other end is connected to the exhaust gas collector 16. A humidity measuring probe 12 connected to the humidifier 11 is installed on the upper part of the quartz glass tube 5. The humidity measuring probe 12 is connected to the humidifier 11. The heat exchange tube 14 is installed through the test section. Temperature measuring probes 13 connected to the temperature display 15 are installed on both the inner and outer walls of the heat exchange tube 14 in the test section.

[0045] The atomization system includes a solution atomizer 6 and an atomizing nozzle 10. The atomizer 6 contains an ammonium chloride solution. The atomizing nozzle 10 is installed inside a quartz glass tube 5. The atomizing nozzle 10 is installed inside the vertical inlet of the quartz glass tube 5 in the test section. The atomizing nozzle 10 is connected to the atomizer 6 outside the quartz glass tube 5 via a pipeline and a corrosion-resistant centrifugal pump 8. A corrosion-resistant electronic flow meter 9 is installed in the pipeline between the atomizing nozzle 10 and the corrosion-resistant centrifugal pump 8. A first valve 7 is installed in the pipeline between the atomizer 6 and the corrosion-resistant centrifugal pump 8.

[0046] The heat exchange system is a water circulation loop, including a water heater 17 and a heat exchange tube 14. The water heater 17 is located outside the test section. One end of the heat exchange tube 14 is connected to one end of the water heater 17 via a water pump 19 and a pipe. The other end of the water heater 17 is connected to the other end of the heat exchange tube 14. A thermometer 20 and a flow meter 21 are installed on the pipe between the heat exchange tube 14 and the water pump 19. A second valve 18 is installed on the pipe between the water heater 17 and the water pump 19.

[0047] The heat exchange tube 14 is arranged at an angle through the quartz glass tube 5 of the test section. The upper end of the heat exchange tube 14 serves as the inlet and is connected to the outlet end of the water heater 17 via the water pump 19 and the pipeline. The lower end of the heat exchange tube 14 serves as the outlet and is connected to the inlet end of the water heater 17.

[0048] The quartz glass tube 5 is a transparent and visible quartz glass tube. The heat exchange tube 14 is fixed at an angle inside the quartz glass tube 5. Water flows inside the heat exchange tube 14. There is gas inside the quartz glass tube 5 with a temperature higher than that of the water. The outer surface of the heat exchange tube 14 is in contact with the hot air in the quartz glass tube 9. Heat exchange is achieved between the lower temperature water and the higher temperature air. The outlet of the heat exchange tube 14 is connected to the water outlet circuit.

[0049] The imaging system includes a microscope camera 22 and a display 23. The heat exchange tube 14 of the test section is transparent and visible inside the quartz glass tube 5. The external microscope camera 22 is directed towards the heat exchange tube 14 inside the quartz glass tube 5 to take pictures. The microscope camera 22 and the display 23 are electrically connected.

[0050] Solution atomizer 6 is an ultrasonic atomizer used to atomize solutions into finer droplets.

[0051] In practice, the solution atomizer 6 atomizes and generates atomized droplets, which are then pumped into the atomizing nozzle 10 by the corrosion-resistant centrifugal pump 8 and sprayed out in the quartz glass tube 5. The atomized droplets sprayed out in the atomizing nozzle 10 evaporate and precipitate crystal particles in the higher temperature gas in the quartz glass tube 5. The formed crystal particles are deposited on the lower temperature heat exchange tube 14. The deposition morphology and deposition position of the crystal particles on the heat exchange tube 14 are observed in real time from the outside of the visualized quartz glass tube 5 towards the heat exchange tube 14 by the microscope camera 22.

[0052] The test section includes humidity measurement inside the quartz glass tube 5, temperature measurement of the inner and outer walls of the heat exchange tube 14, and filming of the deposition process of crystal particles on the outer wall of the heat exchange tube 14. The humidity measurement probe 12 measures the humidity (RH) inside the test section.

[0053] like Figure 1 As shown, in the heating system, fan 1 draws in outside air from the inlet, and the outlet of fan 1 is connected to the inlet of air heater 3. The circuits of fan 1 and air heater 3 are connected to controller 2. Controller 2 includes a power switch, a temperature regulator, and a frequency converter. The temperature regulator is set to a certain temperature value (T). 加 and T flow Heating is achieved through a temperature regulator that controls temperatures from 0℃ to 400℃, while a frequency converter adjusts the fan speed and controls the inlet air velocity. 气 The air velocity varies from 0 m / s to 16 m / s; the outlet of the air heater 3 is connected to the anemometer 4 through a high-temperature resistant duct, and the anemometer measures the air velocity υ entering the test section. flow Anemometer 4 is connected to the horizontal inlet of the quartz glass tube 5 in the test section; the atomization system includes a solution atomizer 6 and atomizing nozzle 10. The solution atomizer 6 is connected in series with a first valve 7, a corrosion-resistant centrifugal pump 8, a corrosion-resistant electronic flow meter 9, and atomizing nozzle 10. The atomizing nozzle 10 is installed inside the vertical inlet of the quartz glass tube 5 in the test section, and then the atomized solution is horizontally sprayed inside the quartz glass tube 5. The corrosion-resistant centrifugal pump 8 provides power for the ammonium chloride solution, and the first valve 7 regulates the flow rate Q of the inlet solution. 雾 The spray flow rate was measured using a corrosion-resistant electronic flow meter 9, and the range was 0 m³ / s. 3 / h~1.5×10 -3 m 3 / h; The solution atomizer 6 is an ultrasonic atomizer that can atomize the solution into fine droplets. The atomized solution droplets sprayed from the atomizing nozzle 10 evaporate and precipitate crystal particles in the high-temperature gas in the quartz glass tube 5. The formed crystal particles are deposited on the low-temperature heat exchange tube 14. The deposition morphology and deposition position of the crystal particles on the heat exchange tube 14 are observed in real time by taking pictures outside the visualized quartz glass tube 5 with a microscope camera 22. A humidity measuring probe connected to the humidifier 11 is installed on the upper part of the quartz glass tube 5. 12. Temperature measuring probes 13, connected to temperature display 15, are installed on the inner and outer walls of the heat exchange tube 14 in the test section. The humidity RH of the test section is changed by adjusting the concentration of the solution in the atomizer 6, and the humidity measuring probe 12 measures the humidity RH of the test section. The heat exchange system is a water circulation loop. The water heater 17 is connected in series with the second valve 18, water pump 19, thermometer 20, flow meter 21, and heat exchange tube 14. The outlet of the heat exchange tube 14 is connected to the water heater 17. The thermometer 20 and flow meter 21 measure the water temperature T, respectively. 水 and traffic Q 水The outlet of the quartz glass tube 5 is connected to the exhaust gas collector 16, which is used to absorb excess particles.

[0054] like Figure 2 As shown, a center position A1 is set at any point on the circumference of the outer wall surface of the heat exchange tube 14 at the midpoint of the axial direction. Temperature measuring probes are installed at the center position A1, two points A2 and A3 on the outer wall surface of the heat exchange tube 14 at a distance of 6 cm axially from the center position A1, and two points A4 and A5 on the outer wall surface of the heat exchange tube 14 at a circumferential angle of 60° from the center position A1 on both sides. The temperature T of the outer wall surface of the heat exchange tube 14 is measured. out Measurement points are A1-A5. Temperature measuring probes are arranged at positions A1'-A5' on the inner wall surface corresponding to measurement points A1-A5 on the outer wall surface for temperature T. in Temperature measurement probe.

[0055] Five temperature sensing elements are set on the outer wall probe. Temperature sensing elements A1-A3 are used to study the deposition differences at different radial positions of the heat exchange tube, and temperature sensing elements A4-A5 are used to study the deposition differences at different circumferential external locations on the outer wall of the heat exchange tube. The probes A1'-A5' on the inner wall correspond to those on the outer wall.

[0056] The heat exchange tube 14 is a detachable component, allowing for different gas flow rates by replacing the heat exchange tube 14. flow Humidity (RH) and heat exchange temperature (T) 水 In the experimental test, after removing the heat exchange tube 14, the heat exchange tube 14 was divided into regions, the amount of crystal particles deposited at different locations was weighed, the deposition rate was calculated, and the micromorphology of the weighed deposits was analyzed.

[0057] Specifically, the heat exchange tube 14 is divided into regions, with the direction of the quartz glass tube 5 viewed from the front during the experiment as 0° and the back of the quartz glass tube 5 as 180°. The heat exchange tube 14 is divided into regions every 10° along its circumference. The amount of crystal particles deposited at different locations is weighed, the deposition rate is calculated, and the micromorphology of the weighed deposits is analyzed.

[0058] The specific embodiments and implementation process of the present invention are as follows:

[0059] Step 1: Turn on the air heating system, turn on the power switch, turn on the fan 1, and adjust the airflow speed at the outlet of the air heater 3. flow Turn on the air heater 3 switch, adjust the temperature controller 2, and set the heating temperature T inside the air heater 3. 加 and outlet temperature T flow To carry out the work;

[0060] Step 2: Turn on the water heater 17 to start heating the water, open the second valve 18, start the water pump 19, and observe the temperature reading T on the thermometer 20. 水 Wait for the temperature reading T 水 After reaching the preset operating temperature, turn off the water heater 17, turn on the flow meter 21, and adjust the opening of the second valve 18. Observe the adjusted water flow rate Q on the flow meter 21. 水 The predetermined operating conditions have been achieved;

[0061] Step 3: Observe the outlet temperature T of the air heater 3 on the controller 2. flow Waiting for the outlet temperature T flow After the predetermined temperature is reached and stabilized, and after the temperature readings T on the thermometer 20 and flowmeter 21 are read... 水 and water flow rate Q 水 After stabilization, record the water temperature and flow rate.

[0062] Step 4: After the reading in Step 3 stabilizes, start the atomization system and the microscope camera 22, open the first valve 7, start the corrosion-resistant centrifugal pump 8, and the solution atomizer 6 atomizes the ammonium chloride solution to produce atomized droplets, which are pumped into the atomizing nozzle 10 by the corrosion-resistant centrifugal pump 8 and sprayed out in the quartz glass tube 5. The atomized droplets sprayed out in the atomizing nozzle 10 evaporate in the higher temperature gas in the quartz glass tube 5 to precipitate crystal particles, and the formed crystal particles are deposited on the lower temperature heat exchange tube 14 to form a deposition layer.

[0063] The atomization flow rate Q of the atomized droplets generated by the ammonium chloride solution is controlled by adjusting the opening degree of the first valve 7. 雾 Observe the corrosion-resistant electronic flow meter 9 and record the real-time atomized flow rate Q. 雾 Turn on the humidifier 11 to record the humidity RH inside the quartz glass tube 5, turn on the microscope camera 22 to photograph the deposition process of ammonium chloride crystal particles on the heat exchange tube 14, and start timing.

[0064] Step 5: Turn on the temperature display 15 and record the temperature T at various measuring points on the inner and outer walls of the heat pipe 14 at regular intervals. in and T out ;

[0065] Step 6: Conduct multiple experiments, record the deposition time t for each experiment, and after each experiment, remove the heat exchange tube 14, weigh the amount of crystal particles deposited on it m, calculate the thickness r(t) and deposition rate ε(t) of the deposition layer at different locations, and obtain the distribution of crystal particles in the deposition layer at different locations.

[0066] Step 7: Following the experimental procedure of steps 1-6, adjust the gas flow rate υ flow Temperature reading T of water heater 17水 and the concentration of the solution in the atomizer 6 is changed to change the humidity RH, and the test of the deposition of the crystalline particles under different conditions is carried out.

[0067] During the test, the thickness r(t) of the deposition layer of the ammonium chloride on the surface of the temperature measuring probe 13 on the heat exchange tube 14 at the time t is obtained by processing the temperatures measured on the outer and inner walls of the heat exchange tube 14 and the outlet temperature of the air heater 3 according to the following formula:

[0068]

[0069] In the formula, r(t) is the thickness of the deposition layer on the surface at the time t, T flow is the outlet temperature of the air heater 3, T out and T in are the temperatures measured by the temperature measuring probe on the outer and inner walls of the heat exchange tube 14 respectively, and R is the thickness between the outer and inner walls of the heat exchange tube 14; λ a and λ w are the thermal conductivities of the deposition layer of the ammonium chloride and the temperature measuring probe respectively, and K represents the thermal conduction thickness, which is assumed to be 1 at the beginning of the experiment, and is calibrated after the preliminary experiment.

[0070] In the experiment, the image deposition thickness change value is calibrated, and the test is combined with the weighing after the test, so as to ensure the accuracy of the online deposition thickness measurement.

[0071] In the specific implementation, the deposition amount of the deposition layer can also be obtained according to the thickness r(t) of the deposition layer, and then the deposition rate under each condition at the time t is obtained by processing according to the following formula:

[0072]

[0073] In the formula, ε(t) is the deposition rate, m is the deposition amount of the deposition layer, S is the area of the deposition area, and t is the time used in the deposition process.

[0074] Specifically, the gas flow rate υ flow , the temperature T 水 of the water heater and the concentration of the solution in the atomizer are adjusted to change the humidity RH, and the experimental test under different conditions is carried out to study the adhesion and deposition mechanism of the ammonium chloride particles on the heat exchange tube.

[0075] As shown in FIGS. 1 to 3, the corresponding relationship diagrams of the deposition amount m and the deposition rate ε(t) at different positions on the surface of the heat exchange tube are obtained by the test. Figure 3 As shown in FIGS. 1 to 3, the corresponding relationship diagrams of the deposition amount m and the deposition rate ε(t) at different positions on the surface of the heat exchange tube are obtained by the test. flow The test conditions are normal temperature and pressure, the material is 20# carbon steel, the experimental time is 1h, the water temperature T 水 is 16℃, and the flow rate υ flowis 5 m / s, the gas temperature T flow is 180 °C, the flow rate Q 雾 of the atomized solution is 0.3 x 10 -3 m 3 / h, the flow rate Q 水 of the water is 2 m 3 / h.

[0076] Although the embodiments of the present application have been shown and described, the technical features of the present application are not limited to the above-described embodiments. Those skilled in the art can make various modifications and changes to the embodiments based on the principles and spirit of the present application, and all modifications and changes are included in the scope of the claims and protection of the present application.

Claims

1. A testing device for ammonium chloride particle deposition characteristics, characterized in that: it comprises an air heating system, a solution atomization system, a testing section, a heat exchange system, a shooting system and a waste gas collector, the testing section is horizontally arranged, the outlet of the air heating system is connected to the horizontal inlet of the testing section, a part of the solution atomization system is installed inside the vertical inlet of the testing section, the heat exchange pipe (14) of the heat exchange system is installed in the middle of the testing section, the outlet of the testing section is connected to the waste gas collector (16), and the shooting system is arranged towards the quartz glass tube (5) of the testing section and takes pictures; the air heating system comprises a fan (1), a controller (2), an air heater (3) and an air speed meter (4), the outlet of the fan (1) is connected to the inlet of the air heater (3), the outlet of the air heater (3) is communicated with one end of the testing section, and the outlet of the air heater (3) is provided with the air speed meter (4), the controller (2) for adjusting the temperature of the inlet and outlet of the air heater (3) and the flow rate of the outlet gas is electrically connected with the fan (1) and the air heater (3); the testing section comprises a quartz glass tube (5), a humidity meter (11), a temperature display (15) and a heat exchange pipe (14), one end of the quartz glass tube (5) is connected to the outlet of the air heater (3), and the other end is connected to the waste gas collector (16), the upper part of the quartz glass tube (5) is provided with a humidity measuring probe (12) connected to the humidity meter (11), and the heat exchange pipe (14) is installed through the testing section, and the inner and outer walls of the heat exchange pipe (14) in the testing section are provided with temperature measuring probes (13) connected to the temperature display (15); the atomization system comprises a solution atomizer (6) and an atomization nozzle (10), the solution atomizer (6) contains ammonium chloride solution, the atomization nozzle (10) is arranged in the quartz glass tube (5), the atomization nozzle (10) is connected to the solution atomizer (6) outside the quartz glass tube (5) through a pipeline and a corrosion-resistant centrifugal pump (8), a corrosion-resistant electronic flow meter (9) is arranged on the pipeline between the atomization nozzle (10) and the corrosion-resistant centrifugal pump (8), and a first valve (7) is arranged on the pipeline between the solution atomizer (6) and the corrosion-resistant centrifugal pump (8); the heat exchange system comprises a water heater (17) and a heat exchange pipe (14), the water heater (17) is located outside the testing section, one end of the heat exchange pipe (14) is connected to one end of the water heater (17) through a water pump (19) and a pipeline, the other end of the water heater (17) is connected to the other end of the heat exchange pipe (14), a thermometer (20) and a flow meter (21) are arranged on the pipeline between the heat exchange pipe (14) and the water pump (19), and a second valve (18) is arranged on the pipeline between the water heater (17) and the water pump (19). 2.The testing device for ammonium chloride particle deposition characteristics according to claim 1, characterized in that: the heat exchange pipe (14) is arranged obliquely through the quartz glass tube (5) of the testing section, the upper end of the heat exchange pipe (14) is connected to the outlet end of the water heater (17) through a water pump (19) and a pipeline as an inlet, and the lower end of the heat exchange pipe (14) is connected to the inlet end of the water heater (17) as an outlet. ​ ​ 3. The ammonium chloride particle deposition property testing device according to claim 1, characterized in that: The heat exchange pipe (14) is fixed inside the quartz glass tube (5) at an angle, water flows inside the heat exchange pipe (14), the quartz glass tube (5) contains gas with a higher temperature than water, the outer surface of the heat exchange pipe (14) is in contact with the hot air in the quartz glass tube (5), and heat exchange occurs between the lower temperature water and the higher temperature air.

4. The ammonium chloride particle deposition property testing device according to claim 1, characterized in that: The shooting system includes a microscopic camera (22) and a display (23), the heat exchange pipe (14) of the test section is inside the transparent quartz glass tube (5), the external microscopic camera (22) shoots the heat exchange pipe (14) inside the quartz glass tube (5), and the microscopic camera (22) and the display (23) are electrically connected.

5. The ammonium chloride particle deposition property testing device according to claim 1, characterized in that: The solution atomizer (6) is an ultrasonic atomizer for atomizing the solution into smaller droplets.

6. The ammonium chloride particle deposition property testing device according to claim 1, characterized in that: The outer wall surface of the heat exchange pipe (14) is provided with a center position A1 at any position of the midpoint in the axial direction, two positions A2 and A3 on the outer wall surface of the heat exchange pipe (14) which are 6 cm away from the center position A1 along the axial direction, and two positions A4 and A5 on the outer wall surface of the heat exchange pipe (14) which are 60° away from the center position A1 along the circumferential direction, and temperature measuring probes are respectively arranged at the positions A1-A5 on the outer wall surface and the positions A1'-A5' on the inner wall surface corresponding to the positions A1-A5 on the outer wall surface. T in temperature measuring probes are respectively arranged at the positions A1-A5 on the outer wall surface and the positions A1'-A5' on the inner wall surface corresponding to the positions A1-A5 on the outer wall surface.

7. A method for testing the particle deposition characteristics of ammonium chloride applied to the device of any one of claims 1-6, characterized by, The method comprises the following steps: Step 1: Turn on the air heating system, turn on the switch of the air blower (1), adjust the air flow speed at the outlet of the air heater (3) υ flow , turn on the switch of the air heater (3), adjust the controller (2), set the heating temperature inside the air heater (3) T 加 and the outlet temperature T flow work; Step 2: Turn on the water heater (17) to start heating water, open the second valve (18), start the water pump (19), and observe the temperature reading on the thermometer (20) T 水 When the temperature reading T 水 reaches the working temperature, turn off the water heater (17), open the flow meter (21), and adjust the opening of the second valve (18) to make the adjusted water flow value Q 水 reach the predetermined working condition; Step 3: Observe the temperature at the outlet of the air heater (3) on the controller (2) T flow , until the outlet temperature T flow reaches a predetermined temperature and stabilizes, and until the water temperature readings T 水 and water flow values Q 水 on the thermometer (20) and flowmeter (21) stabilize Step 4: Record the stabilized water temperature and water flow Step 4: After the time in step 3 is stable, start the atomization system and the microscopic camera (22), open the first valve (7), start the corrosion-resistant centrifugal pump (8), the solution atomizer (6) atomizes the ammonium chloride solution to generate atomized droplets, which are pumped into the atomization nozzle (10) by the corrosion-resistant centrifugal pump (8) and sprayed out in the quartz glass tube (5), the atomized droplets sprayed out of the atomization nozzle (10) evaporate and precipitate crystalline particles in the high-temperature gas in the quartz glass tube (5), and the formed crystalline particles deposit on the lower-temperature heat exchange pipe (14) to form a deposition layer; The atomization flow rate of the atomized droplets generated by the ammonium chloride solution is controlled by adjusting the opening of the first valve (7) Q 雾 An anticorrosion electronic flow meter (9) is observed and the atomization flow rate is recorded Q 雾 The humidity inside the quartz glass tube (5) is recorded by opening the humidity meter (11) RH The deposition process of the ammonium chloride crystal particles on the heat exchange tube (14) is photographed by opening the microscope camera (22), and the timing is started Step 5: Turn on the temperature display (15) and record the temperature of each measuring point on the inner and outer wall of the tube (14) at equal intervals T in and T out ; Step 6: record the time length of each test t , and take out the heat exchange tube (14) after each test to weigh the amount of deposited crystalline particles m , calculate the thickness of the deposited layer at different positions r ( t ) and the deposition rate , and obtain the distribution of crystalline particles in the deposited layer at different positions; Step 7: Adjust the gas flow rate according to the experimental procedure of Step 1-6 υ flow Temperature reading of the water heater (17) T 水 And changing the concentration of the solution in the atomizer (6) to change the humidity RH , The deposition of crystalline particles under different working conditions is tested.

8. The ammonium chloride particle deposition property testing method according to claim 7, characterized in that: During the test, the temperature on the heat exchange tube (14) is obtained by processing the temperature measured on the outer and inner wall surface of the heat exchange tube (14), the outlet temperature of the air heater (3) according to the following formula t The thickness of the deposition layer on the surface of the temperature measuring probe (13) at the moment r ( t ) is ； wherein r t t the thickness of the deposited layer on the surface of the schedule, T flow the outlet temperature of the air heater (3), T out , T in are the temperatures measured by the temperature measuring probes on the outer and inner wall surface of the heat exchange tube (14), respectively, R is the thickness between the outer and inner wall surface of the heat exchange tube (14); λ a , λ w are the thermal conductivities of the deposited layer and the temperature measuring probe, respectively, K denotes the thermal conduction thickness, which is assumed to be K 1 at the beginning of the experiment, and the value of K is calibrated after the preliminary experiment.​​

Images