Test system and test method for optimizing heat and mass transfer improvement effect of rectifying tower

Abstract

The invention discloses a test system and a test method for optimizing a heat and mass transfer improvement effect of a rectifying tower. The test system comprises a first rectifying tower (1), a second rectifying tower (2), an ultrasonic controller (7), a working condition control system, a solution preparation system, a guarantee system and a high-precision parameter measurement and acquisition system, the ultrasonic controller controls the power, the frequency and the phase of an annular oscillator (5) and a strip-shaped atomizer (6) in the ultrasonic oscillation atomization ring (3), and the phase difference is controlled by setting the oscillation starting time through a single chip microcomputer; and controlling and recording corresponding parameters according to the set parameters. By testing the rectification characteristics of the first rectifying tower and the second rectifying tower when the first rectifying tower and the second rectifying tower run under different working parameters, the improvement condition of heat and mass transfer of the optimized rectifying tower is quantitatively presented, the testing method is simplified, the testing accuracy is improved, the time is saved, and the testing method for the heat and mass transfer improvement effect of the rectifying tower after tower internals are optimized has universality.

Description

Technical Field

[0001] The present invention belongs to the technical field of enhancing heat and mass transfer performance in the rectification process, and particularly relates to a test system and a test method for optimizing the heat and mass transfer improvement effect of a rectification column. Background Art

[0002] As an important separation device, the rectification column is widely used in industries such as chemical engineering, refrigeration, and petroleum. However, it has problems such as a large size, low performance coefficient, and high cost. Therefore, it is very necessary to vigorously carry out research on optimizing rectification technology. And measuring the improvement effect of optimizing the heat and mass transfer of the rectification column is a key link among them. In the prior art, the test of the improvement effect of optimizing the heat and mass transfer of the rectification column is usually completed in a single rectification column. The optimized and unoptimized internals are installed in the column in sequence, and the optimized and unoptimized rectification columns are tested under the same working conditions successively. According to the measurement data, the overall column mass transfer amount and the purity of the outlet ammonia vapor of the two types of columns are obtained. Finally, the improvement effect of the heat and mass transfer of the optimized rectification column is obtained by comparison. However, this method has the following deficiencies: First, during the test process, the internals are replaced sequentially, and it is easy to introduce human errors during the replacement process; when measuring before and after the replacement, it is easy to increase random errors; these two types of errors increase the uncertainty of the test. Second, after completing the experiment and analyzing the data, if a re-experiment is required, the internals need to be replaced again, which is cumbersome and time-consuming. Third, the existing measurement methods hardly consider the concentration of ammonia components at different height positions inside the column, so the improvement of heat and mass transfer inside the optimized column cannot be shown. Summary of the Invention

[0003] Technical Problem: In order to solve the problems existing in the above-mentioned existing measurement technologies, the present invention proposes a test system and a test method for optimizing the heat and mass transfer improvement effect of a rectification column. It greatly reduces human errors and random errors, improves the accuracy of the test, simplifies the experimental operation, and saves time; sampling points are set at different height positions inside the column, and the concentrations of ammonia components in the gas and liquid phases at different positions inside the column can be measured to quantitatively reflect the driving force of gas-liquid mass transfer.

[0004] Technical Solution: A test system for optimizing the heat and mass transfer improvement effect of a rectification column according to the present invention includes a first rectification column, a second rectification column, an ultrasonic controller, a working condition control system, a solution preparation system, a guarantee system, and a high-precision parameter measurement and acquisition system;

[0005] The first distillation column uses an ultrasonic oscillating atomization ring as the packing; the upper part of the first distillation column is connected to a condenser through a fifth flowmeter, and the condenser is connected to a constant temperature water bath; the condensate outlet pipe of the condenser is connected to a liquid storage tank, and after passing through a first flowmeter and a first valve in sequence, it is divided into two paths by a three-way valve. One path is connected to the upper side of the first distillation column through a third flowmeter, and the other path is connected to the generator through a second valve; the ultrasonic controller-controlled ultrasonic oscillating atomization ring is arranged inside the first distillation column; the lower part of the first distillation column is connected to the generator through a fourth flowmeter, and the side of the lower part of the first distillation column is connected to the generator through a second flowmeter.

[0006] The second distillation column described above is used as a control group. Except that the packing inside the column is a Pall ring, other structures and dimensions are exactly the same as those of the first distillation column.

[0007] An electric heater is provided inside the generator, and the generator is also connected to a distilled water tank, an ammonia tank, a circulating water pump, and a nitrogen gas cylinder respectively.

[0008] The ultrasonic oscillating atomization ring is a packing ring designed by integrating a multi-frequency ultrasonic ring oscillator, a strip atomizer, and a Pall ring. The ring oscillator is fixed in the middle of the Pall ring to disturb the solution flowing along the wall surface of the Pall ring. The strip atomizers are arranged axially along the inner and outer walls of the Pall ring to atomize the solution flowing through the surface of the strip atomizers into droplets. The Pall ring is divided into upper and lower parts. Four openings are provided on the peripheral wall of the upper half part, and window leaves are provided on the openings; four openings symmetric to the upper half part are provided on the peripheral wall of the lower half part, and window leaves are provided on the openings.

[0009] The working condition control system described above includes a generator, an electric heating controller, an electric heater, a condenser, a liquid storage tank, a constant temperature water bath, and a flow regulating valve for controlling the working conditions; the generator is heated by a group-adjustable electric heater controlled by an electric heating controller, and the upper ports of the generator are respectively connected to the inlets of the first distillation column and the second distillation column to ensure that the working parameters of the rising steam in the two distillation columns are the same.

[0010] The solution preparation system includes a distilled water tank, an ammonia tank, and a precision electronic balance; the distilled water tank and the ammonia tank are directly connected to the generator, and the mass of the distilled water and ammonia entering the generator is measured by the precision electronic balance to prepare the solution; after preparation, it is cut off by a connecting valve; according to the mass fraction of the solution required for the working condition, a certain amount of distilled water is first injected into the generator, and then a certain amount of ammonia gas is slowly injected from the bottom of the generator, and the circulating water pump is used to assist in stirring to ensure that the ammonia gas is fully absorbed by the water to complete the preparation of the required solution.

[0011] The guarantee system described above includes a nitrogen gas cylinder and a vacuum pump; before preparing the solution, the system is flushed and purged with tap water and nitrogen gas to ensure that there is no residual ammonia water solution in each device before; the vacuum pump is used to evacuate the system after flushing and purging and before each solution preparation.

[0012] The described high-precision parameter measurement and acquisition system includes a temperature sensor, a pressure sensor, an electrical parameter meter, a mass flow meter, a gas chromatograph, a data acquisition instrument, and an electronic computer; the temperature sensor is used to measure the temperatures of the inlet and outlet of the rectification column, at different heights inside the column, of the solution and vapor in the generator, and of the cooling water at the inlet of the condenser; the mass flow meter measures the inlet and outlet flows of the vapor and solution in the rectification column; the pressure sensor measures the pressures at the top and bottom of the column and at different heights inside the column; the gas chromatograph is used to measure and analyze the mass fractions of the vapor at the inlet and outlet of the rectification column and at different heights inside the column; a precision electronic balance weighs the masses of distilled water and ammonia required for preparing the solution to determine the mass fraction of the prepared solution; the electrical parameter meter measures the power of the electric heater and the power and frequency of the ultrasonic oscillator; the electronic computer records, analyzes, and processes the temperature, pressure, flow rate, and electrical parameters collected by the data acquisition instrument.

[0013] The test method of the test system for optimizing the heat and mass transfer improvement effect of the rectification column of the present invention includes the following steps:

[0014] Step 1. Before starting, sequentially perform equipment inspection, system flushing, pneumatic experiment, and vacuum pumping on the system. After completing the above work, prepare the solution required for the working conditions in the generator.

[0015] Step 2. Turn on the cooling water system, keep the supply water temperature of the constant temperature water bath stable, and set the initial values of the cooling water flows of the two condensers to be the same through the regulating valve.

[0016] Step 3. Turn on the electric heating controller, set the electric heating power according to the required vapor generation amount under the working conditions, and the ammonia water solution in the generator is heated to generate ammonia water mixed vapor; then turn on the ultrasonic controller in the first rectification column to control the ring oscillator strip atomizer to start the operation of the rectification column system.

[0017] Step 4. After the system starts to operate, the vapor enters the first rectification column and the second rectification column, and the vapor at the top outlet enters the corresponding condensers respectively and is condensed into liquid, and then enters the liquid storage tank.

[0018] Step 5. During the operation process, use the working condition control system to control the top pressure and the liquid level of the generator, adjust the cooling water flow through the regulating valve to keep the rectification column top pressure stable, and keep the liquid level in the ammonia tank stable by controlling the opening of the first regulating valve. At this time, the mass flow rate m M5 of the vapor leaving the top is equal to the mass flow rate m M1 of the solution; adjust the reflux ratios of the first rectification column and the second rectification column by adjusting the second regulating valve to make them the same, and carry out the control operation.

[0019] Step 6. When the readings of all the measuring instruments in the system are stable and the liquid levels in the generator and the liquid storage tank remain unchanged, it indicates that the system operation has reached a stable state. At this time, read the first flowmeter, the second flowmeter, the third flowmeter, the fourth flowmeter, and the fifth flowmeter. At the same time, take samples of the vapor and the solution at the corresponding sampling port positions for analysis to obtain the mass fractions of ammonia and water in each sample.

[0020] Step 7. Calculate the mass transfer amount per unit time of ammonia and water on the vapor side and the solution side. If the mass transfer amounts of the same component on the vapor side and the solution side are the same, record the tower top pressure, the temperatures, mass fractions, and flow parameters of the solution and the vapor at the inlet and outlet of the distillation column, the temperature, pressure, and mass fraction parameters at each measuring point in the tower, and the power and frequency parameters of the ultrasonic oscillation and atomization.

[0021] The ultrasonic controller controls the power, frequency, and phase of the ring oscillator and the strip atomizer in the ultrasonic oscillation atomization ring. The phase difference is controlled by setting the starting oscillation time through a single-chip microcomputer. The scheme of connecting the same group of ultrasonic oscillation atomization rings to one ultrasonic controller is adopted, and the corresponding parameters are controlled and recorded according to the set parameters.

[0022] Adjust the cooling water flow rate at the outlet of the constant temperature water bath through the flow regulating valve to control the working pressure of the distillation column. The first valve controls the liquid level in the liquid storage tank to keep it stable, and the second valve adjusts the flow rate of the reflux liquid entering the top of the distillation column. Determine the system stability by measuring that the solution mass flow rate measured by the first flowmeter is equal to the vapor flow rate at the outlet of the top of the distillation column by the fifth flowmeter. The third flowmeter measures the flow rate of the reflux liquid entering the top of the tower, and then calculates the reflux ratio. The second flowmeter measures the flow rate of the solution at the bottom outlet of the tower. The solution sampler and the vapor sampler respectively take samples of the gas and liquid at the inlet and outlet of the distillation column and the gas phase at different heights inside the tower for the detection of the mass fractions of ammonia and water.

[0023] Beneficial effects: Compared with the existing research, the present invention includes two distillation columns. The first distillation column 1 is equipped with optimized internals, and the second distillation column 2 is equipped with unoptimized internals. During the experiment, the replacement of the internals is avoided, and the measurements are carried out simultaneously in the first distillation column 1 and the second distillation column 2, greatly reducing the human error and random error, improving the accuracy of the test, simplifying the experimental operation, and saving time. Sampling points are set at different heights inside the tower, which can measure the concentrations of ammonia components in the gas and liquid phases at different positions inside the tower and quantitatively reflect the driving potential of gas-liquid mass transfer. Description of the Drawings

[0024] Figure 1 is a schematic diagram of the principle of the present invention;

[0025] Figure 2 is a schematic diagram of the structure of the oscillation atomization ring;

[0026] In the figure: there are a first rectification column 1, a second rectification column 2, an ultrasonic oscillation atomization ring 3, a Pall ring 4, a ring oscillator 5, a strip atomizer 6, an ultrasonic controller 7, a generator 8, an electric heating controller 9, an electric heater 10, a condenser 11, a liquid storage tank 12, a constant temperature water bath 13, a flow regulating valve 14, a three-way valve 15, a solution sampler 16, a vapor sampler 17, a distilled water tank 18, an ammonia tank 19, a precision electronic balance 20, a circulating water pump 21, a nitrogen cylinder 22, a vacuum pump 23, a temperature sensor 24, a pressure sensor 25, an electrical parameter meter 26, a mass flow meter 27, a gas chromatograph 28, a data acquisition instrument 29, and an electronic computer 30. Specific embodiments

[0027] The present invention will be further clarified below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. After reading the present invention, various equivalent modifications made by those skilled in the art to the present invention fall within the scope defined by the appended claims of this application.

[0028] As Figure 1 shown, the test system for optimizing the heat and mass transfer improvement effect of the rectification column of the present invention includes a first rectification column 1 (with an ultrasonic oscillation atomization ring as the packing), a second rectification column 2 (with a Pall ring as the packing), an ultrasonic controller, a working condition control system, a solution preparation system, an experimental support system, and a high-precision parameter measurement and acquisition system.

[0029] The first rectification column 1 uses the ultrasonic oscillation atomization ring 3 as the packing; the second rectification column 2 is used as a control group. Except that the packing in the column is a Pall ring 4, other structures and dimensions are exactly the same as those of the first rectification column 1.

[0030] As Figure 2 shown, the oscillation atomization ring 3 is a packing ring designed by integrating a multi-frequency ultrasonic ring oscillator 5, a strip atomizer 6, and a Pall ring 4. The ring oscillator 5 is fixed in the middle of the Pall ring 4 to disturb the solution flowing along the wall surface of the ring, and the strip atomizer 6 is arranged axially along the Pall ring 4 to atomize the solution flowing through the surface of the strip atomizer 6 into droplets.

[0031] The ultrasonic controller 7 group controls the ultrasonic oscillator parameters (the power, frequency, and phase of the ultrasonic oscillator 5 and the atomizer 6). The phase difference is controlled by setting the starting time of the oscillation through a single-chip microcomputer, and the cable entering the rectification column is sealed and protected with epoxy resin; an experimental design scheme of using the same group of oscillators to access a single ultrasonic controller 7 is adopted, and the corresponding parameters are controlled and recorded according to the set parameters.

[0032] The described operating condition control system includes a generator 8, an electric heating controller 9, an electric heater 10, a condenser 11, a liquid storage tank 12, a constant temperature water bath 13, and a flow regulating valve 14 for controlling the operating conditions. The generator 8 is heated by a group-adjustable electric heater 10. The upper end of the generator 8 is respectively connected to the inlets of the first distillation column 1 and the second distillation column 2 to ensure that the operating parameters of the rising vapors in the two bodies are the same. The condensers 11 of the first distillation column 1 and the second distillation column 2 have the same structure and are connected to the vapor outlets of the corresponding bodies. The vapor flows through the fifth flowmeter M5 and then enters the condenser 11 for condensation. The condensation heat is carried away by the cooling water system. The flow rate of the cooling water at the outlet of the constant temperature water bath 13 is adjusted by the flow regulating valve 14 to control the operating pressure of the distillation column. The liquid storage tank 12 is arranged below the condenser 11. After condensation, the solution passes through the first flowmeter M1 and the first valve V1 and then is divided into two paths by the three-way valve 15. One path passes through the third flowmeter M3 and enters the top of the tower as the reflux liquid, and the other path enters the generator 8 after passing through the second valve V2. The first valve V1 controls the liquid level in the liquid storage tank 12 to keep it stable, and the second valve V2 adjusts the flow rate of the reflux liquid entering the top of the tower. The system stability is judged by the equality of the measured solution mass flow rate by the first flowmeter M1 and the vapor flow rate at the top outlet of the tower (measured by the fifth flowmeter M5); the third flowmeter M3 measures the flow rate of the reflux liquid entering the top of the tower, and then the reflux ratio is calculated. The second flowmeter M2 measures the flow rate of the solution at the bottom outlet of the tower. The solution sampler 16 and the vapor sampler 17 respectively sample the gas-liquid inlets and outlets of the distillation column and the gas phase at different heights inside the tower for detecting the mass fractions of ammonia and water.

[0033] The described solution preparation system includes a distilled water tank 18, an ammonia tank 19, and a precision electronic balance 20. The distilled water tank 18 and the ammonia tank 19 are directly connected to the generator 8. The mass of the distilled water and ammonia entering the generator 8 is measured by the precision electronic balance 20 to prepare the solution. After preparation, the connection valve is cut off. According to the mass fraction of the solution required for the experimental operating conditions, a certain amount of distilled water is first injected into the generator 8, and then a certain amount of ammonia gas is slowly injected from the bottom of the generator 8, and the circulating water pump 21 is used to assist in stirring to ensure that the ammonia gas is fully absorbed by the water to complete the preparation of the required solution.

[0034] The described experimental guarantee system includes a nitrogen gas cylinder 22 and a vacuum pump 23. Before preparing the solution, the system is flushed and purged with tap water and nitrogen gas to ensure that there is no residual ammonia water solution in each device before the experiment. The vacuum pump 23 is used to evacuate the experimental system after flushing and purging and before each solution preparation.

[0035] The described high-precision parameter measurement and acquisition system includes a temperature sensor 24, a pressure sensor 25, an electrical parameter meter 26, a mass flow meter 27, a gas chromatograph 28, a data acquisition instrument 29, and an electronic computer 30. The temperature sensor 24 is used to measure the temperatures of the inlet and outlet of the rectification column, at different heights inside the column, of the solution and vapor in the generator 8, and of the cooling water at the inlet of the condenser 11; the mass flow meter 27 measures the inlet and outlet flows of the vapor and solution in the rectification column; the pressure sensor 25 measures the pressures at the top, bottom, and different heights inside the column; the gas chromatograph 28 is used to measure and analyze the mass fractions of the vapor at the inlet and outlet of the rectification column and at different heights inside the column; a precision electronic balance 20 weighs the masses of distilled water and ammonia required for preparing the solution to determine the mass fraction of the prepared solution; the electrical parameter meter 26 measures the power of the electric heater 10 and the power and frequency of the ultrasonic oscillator. The electronic computer 30 records, analyzes, and processes the data (such as temperature, pressure, flow rate, electrical parameters, etc.) collected by the data acquisition instrument 29.

[0036] The test method of the present invention based on the above-mentioned optimized test system for enhancing the heat and mass transfer effect of the rectification column includes: the test method for the mass transfer per unit time of ammonia and water components, and the test method for the mass transfer driving potential at different heights inside the column.

[0037] The test method for the mass transfer per unit time of ammonia and water components is as follows:

[0038] Measure the mass transfer per unit time of ammonia and water components on both the solution side and the vapor side simultaneously: Calculate the mass transfer per unit time of the two components on the solution side through the solution flow rate and mass fraction at the inlet and outlet of the rectification column, and calculate the mass transfer per unit time of the two components on the vapor side through the vapor flow rate and mass fraction at the inlet and outlet of the rectification column. The calculation results of the two are mutually calibrated to ensure the accuracy of the measurement results.

[0039] Taking the mass transfer of ammonia component as an example, the mass transfer per unit time of ammonia component on the vapor side is:

[0040] m a,v =m M5 ·ξ″ a,out -m M4 ·ξ″ a,in

[0041] In the formula, m a,v (kg·s -1 ) represents the mass transfer per unit time of ammonia component on the vapor side, ξ″ a,in 、ξ″ a,out (%) respectively represent the mass fractions of ammonia component in the vapor at the inlet and outlet of the rectification column, which are determined by sampling and analysis using the gas chromatograph 28. m M4 、m M5 (kg·s -1represent the mass flow rates of the inlet and outlet vapors of the rectification column under steady flow, respectively, and are measured by the mass flowmeter 27 (the fourth flowmeter M4 and the fifth flowmeter M5).

[0042] The mass transfer of ammonia on the solution side is as follows:

[0043] m a,s = m M3 ·ξ′ a,in - m M2 ·ξ′ a,out

[0044] In the formula, m a,s (kg·s -1 ) represents the mass transfer of ammonia component per unit time on the solution side, and ξ′ a,in , ξ′ a,out (%) represent the mass fractions of ammonia components in the inlet and outlet solutions of the rectification column, respectively, and are measured by sampling with the gas chromatograph 28. m M3 , m M2 (kg·s -1 ) represent the mass flow rates of the inlet and outlet liquids of the rectification column under steady flow, respectively, and are measured by the mass flowmeter 27 (the third flowmeter M3 and the second flowmeter M2).

[0045] Calibrate the calculation results of the mass transfer per unit time of ammonia and water components on the solution side and the vapor side with each other. If the difference is less than 5%, the experimental results are considered reliable. Record all data and use the data for the analysis of the mass transfer characteristics of the rectification process.

[0046] The test method for the mass transfer driving potential at different heights in the column is as follows:

[0047] Measure the gas-liquid parameters at different heights of the column simultaneously: Measure the mass fractions of ammonia and water on the solution side and the vapor side by sampling with the gas chromatograph 28 and convert them into mole fractions, measure the solution side temperature with the temperature sensor 24, and measure the pressure with the pressure sensor 25.

[0048] Take the calculation of the differential pressure mass transfer driving potential (ΔP a ) of ammonia component as an example:

[0049]

[0050] In the formula, P a o (MPa) represents the saturated pressure of pure ammonia corresponding to the measured solution temperature and is obtained by calculating the thermodynamic properties of pure ammonia; represents the ammonia mole fraction of the saturated solution corresponding to the solution temperature and the pressure at the column height and is obtained by calculating the thermodynamic properties of the solution; P (MPa) represents the measured pressure at different column heights; y a (%) represents the ammonia mole fraction on the vapor side at different column heights.

[0051] Testing of rectification characteristics under different working parameters:

[0052] 1) Keep the reflux ratio unchanged and change the ultrasonic parameters for experiments to obtain the influence data of ultrasonic oscillation and atomization parameters on rectification characteristics and the mass transfer driving potential of ammonia and water at different heights in the tower.

[0053] 2) Change the reflux ratio for experiments to obtain the influence data of ultrasonic parameters on rectification characteristics under different reflux ratio conditions and obtain the optimal ultrasonic parameters under the minimum reflux ratio condition.

[0054] 3) Keep the total ultrasonic power constant and change the ultrasonic power, frequency and other parameters at different heights of the tower for experiments to obtain the optimal combination of ultrasonic parameters for improving rectification performance.

[0055] 4) Change the working pressure of the rectification tower for experiments to obtain the influence data of ultrasonic parameters on rectification characteristics.

[0056] 5) Change the vapor flow rate (change the power of the electric heater 10) for experiments to obtain the influence data of ultrasonic parameters on rectification characteristics.

[0057] 6) Change the solution concentration in the generator 8 for experiments. Inject the solutions in all the liquid storage tanks 12 into the generator 8 by gravity, then inject an appropriate amount of ammonia or distilled water into the generator 8 to adjust the solution concentration, keep other parameters unchanged, and obtain the influence data of different vapor inlet concentrations on ultrasonic enhanced rectification characteristics.

[0058] Compared with the prior art, the technical effects of the present invention include:

[0059] 1) Accuracy: The optimized and unoptimized tower internals of the present invention are respectively installed in the first rectification tower and the second rectification tower, avoiding the need to replace tower internals in the traditional testing method, and the measurement is carried out in the first rectification tower and the second rectification tower simultaneously, minimizing human error and random error to improve the accuracy of the test.

[0060] 2) Time-consuming: The present invention avoids replacing tower internals and simplifies the operation; after the experiment, according to the analysis of the test data, if more data needs to be obtained through testing, the experiment can be directly carried out without considering the replacement of optimized and unoptimized tower internals, saving time.

[0061] 3) Enhancement effect of heat and mass transfer: The traditional testing method only presents the enhanced performance of heat and mass transfer after optimization by measuring the relevant gas-liquid parameters at the inlet and outlet of the rectification tower, and cannot reflect the improvement of heat and mass transfer inside the tower. The measurement points of the present invention cover the measurement points of the traditional testing method, and gas-liquid sampling points are also set inside the tower to obtain the concentration of ammonia components at different height positions, which can show the improvement of the transfer of ammonia components between gas and liquid inside the optimized tower.

[0062] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A test system for optimizing the heat and mass transfer improvement effect of a distillation column, characterized in that: The test system includes a first rectification column (1), a second rectification column (2), an ultrasonic controller (7), a working condition control system, a solution preparation system, a guarantee system, and a high-precision parameter measurement and acquisition system; The first rectification column (1) uses an ultrasonic oscillation atomization ring (3) as the packing; the upper part of the first rectification column (1) is connected to a condenser (11) through a fifth flowmeter (M5), and the condenser (11) is connected to a constant temperature water bath (13); the condensate outlet pipe of the condenser (11) is connected to a liquid storage tank (12), and after passing through a first flowmeter (M1) and a first valve (V1) in sequence, it is divided into two paths by a three-way valve (15). One path is connected to the upper side of the first rectification column (1) through a third flowmeter (M3), and the other path is connected to a generator (8) through a second valve (V2); an ultrasonic oscillation atomization ring (3) controlled by an ultrasonic controller (7) is arranged inside the first rectification column (1); the lower part of the first rectification column (1) is connected to the generator (8) through a fourth flowmeter (M4), and the side of the lower part of the first rectification column (1) is connected to the generator (8) through a second flowmeter (M2); The second rectification column (2) is used as a control group. Except that the packing in the column is a Pall ring (4), other structures and dimensions are exactly the same as those of the first rectification column (1); An electric heater (10) is provided inside the generator (8), and the generator (8) is also connected to a distilled water tank (18), an ammonia tank (19), a circulating water pump (21), and a nitrogen cylinder (22) respectively.

2. The test system for optimizing the heat and mass transfer improvement effect of a rectification column according to claim 1, characterized in that, The ultrasonic oscillation atomization ring (3) is a packing ring designed by integrating a multi-frequency ultrasonic ring oscillator (5), a strip atomizer (6) and a Pall ring. The ring oscillator (5) is fixed in the middle of the Pall ring (4) to disturb the solution flowing along the wall surface of the Pall ring (4), and the strip atomizer (6) is axially arranged along the inner and outer walls of the Pall ring to atomize the solution flowing through the surface of the strip atomizer (6) into droplets.

3. The test system for optimizing the heat and mass transfer improvement effect of the rectification column according to claim 2, wherein, The Pall ring (4) is divided into upper and lower parts. There are 4 openings on the peripheral wall of the upper half part, and window leaves are provided on the openings; 4 openings symmetric to the upper half part are provided on the peripheral wall of the lower half part, and window leaves are provided on the openings.

4. A test system and test method for optimizing the heat and mass transfer improvement effect of a rectification column, characterized in that, The working condition control system includes a generator (8), an electric heating controller (9), an electric heater (10), a condenser (11), a liquid storage tank (12), a constant temperature water bath (13) and a flow regulating valve for controlling the working conditions; the generator (8) uses the electric heating controller (9) to group-adjust the electric heater (10) for heating. The upper port of the generator (8) is respectively connected to the inlets of the first rectification column (1) and the second rectification column (2) to ensure that the working parameters of the rising steam in the two rectification columns are the same.

5. The test system for optimizing the heat and mass transfer improvement effect of a rectification column according to claim 1, characterized in that, The described solution preparation system includes a distilled water tank (18), an ammonia tank (19), and a precision electronic balance (20); the distilled water tank and the ammonia tank are directly connected to the generator (8), and the mass of the distilled water and ammonia entering the generator is measured by the precision electronic balance to prepare the solution; after preparation, it is cut off by the connecting valve; according to the mass fraction of the solution required by the working conditions, a certain amount of distilled water is first injected into the generator, and then a certain amount of ammonia gas is slowly injected from the bottom of the generator, and a circulating water pump is used to assist in stirring to ensure that the ammonia gas is fully absorbed by the water to complete the preparation of the required solution.

6. The test system for optimizing the heat and mass transfer improvement effect of a rectification column according to claim 1, characterized in that, The described guarantee system includes a nitrogen gas cylinder (22) and a vacuum pump (23); before preparing the solution, the system is flushed and purged with tap water and nitrogen gas to ensure that there is no residual ammonia water solution in each device before; the vacuum pump is used to evacuate the system after flushing and purging and before each solution preparation.

7. The test system for optimizing the heat and mass transfer improvement effect of a rectification column according to claim 1, characterized in that, The described high-precision parameter measurement and acquisition system includes a temperature sensor (24), a pressure sensor (25), an electrical parameter meter (26), a mass flow meter (27), a gas chromatograph (28), a data acquisition instrument (29), and an electronic computer (30); the temperature sensor is used to measure the temperatures of the inlet and outlet of the rectification column, at different heights inside the column, the solution and vapor inside the generator, and the inlet cooling water temperature of the condenser; the mass flow meter measures the inlet and outlet flows of the rectification column vapor and solution; the pressure sensor measures the pressures at the top, bottom, and different heights inside the column; the gas chromatograph is used to measure and analyze the mass fractions of the vapor at the inlet and outlet of the rectification column and at different heights inside the column; the precision electronic balance weighs the mass of the distilled water and ammonia required for preparing the solution to determine the mass fraction of the prepared solution; The electrical parameter meter measures the power of the electric heater and the power and frequency of the ultrasonic oscillator; the electronic computer records, analyzes, and processes the temperature, pressure, flow rate, and electrical parameters collected by the data acquisition instrument.

8. A test method for a test system for optimizing the heat and mass transfer enhancement effect of a rectification column according to any one of claims 1-7, characterized in that It includes the following steps: Step 1. Before starting, sequentially conduct equipment inspection, system flushing, pneumatic experiment, and vacuum pumping on the system. After completing the above work, prepare the solution required by the working conditions in the generator; Step 2. Turn on the cooling water system, keep the supply water temperature of the constant temperature water bath (13) stable, and set the initial values of the cooling water flows of the two condensers (11) to be the same through the regulating valve; Step 3. Turn on the electric heating controller (9), set the electric heating power according to the required vapor generation amount of the working conditions, and the ammonia water solution in the generator (8) is heated to generate ammonia water mixed vapor; then turn on the ultrasonic controller (7) in the first rectification column (1) to control the ring oscillator (5) and the strip atomizer (6) to start the operation of the rectification column system; Step 4. After the system starts to operate, the vapor enters the first rectification column (1) and the second rectification column (2), and the vapor at the top outlet enters the corresponding condensers (11) to be condensed into liquid, and then enters the liquid storage tank (12); Step 5. During the operation process, a working condition control system is used to control the top pressure of the tower and the liquid level of the generator. The cooling water flow rate is adjusted through a regulating valve to keep the top pressure of the rectification tower stable. By controlling the opening degree of the first regulating valve (V1), the liquid level in the ammonia tank (19) is kept stable. At this time, the vapor mass flow rate m M5 leaving the top of the tower is equal to the solution mass flow rate m M1 ; The reflux ratios of the first rectification tower (1) and the second rectification tower (2) are adjusted by the second regulating valve (V2) to keep them the same, and the control run is carried out; Step 6. When the readings of all the measuring instruments in the system are stable and the liquid levels in the generator and the liquid storage tank remain unchanged, it indicates that the system operation has reached a stable state. At this time, read the values of the first flowmeter (M1), the second flowmeter (M2), the third flowmeter (M3), the fourth flowmeter (M4), and the fifth flowmeter (M5). Meanwhile, take samples of the vapor and the solution at the corresponding sampling port positions for analysis to obtain the mass fractions of ammonia and water in each sample. Step 7. Calculate the mass transfer amount per unit time of ammonia and water on the vapor side and the solution side. If the mass transfer amounts of the same component on the vapor side and the solution side are the same, record the tower top pressure, the temperatures, mass fractions, and flow parameters of the solution and the vapor at the inlet and outlet of the distillation column, the temperature, pressure, and mass fraction parameters at each measuring point in the tower, as well as the power and frequency parameters of the ultrasonic oscillation and atomization.

9. The testing method of the testing system for optimizing the heat and mass transfer improvement effect of a rectification column, as claimed in claim 8, wherein The ultrasonic controller (7) controls the power, frequency, and phase of the ring oscillator (5) and the strip atomizer (6) in the ultrasonic oscillation atomization ring (3). The phase difference is controlled by setting the starting oscillation time through the single-chip microcomputer. The scheme of connecting the same set of ultrasonic oscillation atomization rings (3) to one ultrasonic controller (7) is adopted to control and record the corresponding parameters according to the set parameters.

10. The test method of the test system for optimizing the heat and mass transfer improvement effect of a rectification column, as claimed in claim 8, wherein Adjust the cooling water flow rate at the outlet of the constant temperature water bath through the flow regulating valve (14) to control the working pressure of the distillation column. The first valve (V1) controls the liquid level in the liquid storage tank (12) to keep it stable, and the second valve (V2) adjusts the reflux liquid flow rate entering the top of the distillation column. Determine the system stability by measuring that the solution mass flow rate measured by the first flowmeter (M1) is equal to the vapor flow rate at the outlet of the top of the distillation column by the fifth flowmeter (M5). The third flowmeter (M3) measures the flow rate of the reflux liquid entering the top of the tower, and then calculates the reflux ratio. The second flowmeter (M2) measures the flow rate of the solution at the bottom outlet of the tower. The solution sampler (16) and the vapor sampler (17) respectively take samples of the gas and liquid at the inlet and outlet of the distillation column and the gas phase at different heights inside the tower for the detection of the mass fractions of ammonia and water.

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