Device and method for testing dynamic water adsorption capacity of drying agent

Abstract

The invention discloses a device and a method for testing the dynamic water adsorption capacity of a drying agent. The device comprises a moisture generating device, a condenser and a drying column which are connected in sequence, the top of the moisture generating device is connected with a first connecting pipeline which is connected with the lower end of the condenser, a containing cavity is formed in the moisture generating device, pure water is contained in the containing cavity, the upper side of the containing cavity is connected with an air inlet pipeline, the condenser is connected with a refrigerating device, and the condenser is connected with the drying column through a second connecting pipeline. A drying agent to be detected is placed in the drying column. The technical scheme has the beneficial effects that the water absorption capacity of the drying agent is tested, and the dynamic drying detection of different drying agents under different water-containing states and pressures is realized.

Description

Technical Field

[0001] The invention relates to the technical field of gas drying, and in particular to a desiccant dynamic water adsorption capacity testing device and a testing method. Background Art

[0002] Molecular sieves, alumina, silica gel, calcium chloride and other desiccants are widely used in the field of gas drying. When purchasing desiccants, manufacturers usually only provide the static water adsorption capacity of the desiccant, but not the dynamic water adsorption capacity, i.e., the dynamic adsorption capacity and dynamic drying effect. The national standard GB / T 8770-2014 stipulates the determination method of the moisture adsorption in nitrogen gas flow by molecular sieve molding products, but it can only test the adsorption capacity of nitrogen gas flow saturated with water vapor at normal pressure and 25±2℃, and cannot test the adsorption capacity of gas with higher pressure and lower water content. In actual applications, especially in the field of gas purification, the moisture content in the raw materials is often lower than that in nitrogen gas flow saturated with water vapor at 25±2℃, but it will affect the subsequent purification process (such as low-temperature distillation, ice blockage may occur), and it needs to be dried before entering the next purification process. Therefore, it is necessary to test the adsorption capacity of the desiccant under the gas conditions of the corresponding water content, i.e., the drying effect and adsorption capacity, in order to determine the regeneration cycle of the desiccant and avoid affecting the subsequent purification process. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a desiccant dynamic water adsorption capacity testing device and a testing method to realize the dynamic water adsorption capacity testing of various desiccants.

[0004] Specifically, the present invention discloses a desiccant dynamic water adsorption capacity testing device, comprising a moisture generating device, a condenser and a drying column connected in sequence; the moisture generating device is connected to a first connecting pipe at the top thereof and connected to the lower end of the condenser; a containing chamber is arranged inside the moisture generating device, the containing chamber is filled with pure water, and the upper side is connected to an air intake pipe; the condenser is connected to a refrigeration device; the condenser is connected to the drying column through a second connecting pipe; and the desiccant to be tested is placed in the drying column.

[0005] The benefit of adopting the above technical solution is that it can realize the water absorption capacity test of the desiccant and realize the dynamic drying detection under different desiccants and different water content states.

[0006] Furthermore, the end of the air inlet pipe extends into the lower side of the liquid surface of the containing chamber, and a gas flow controller is provided on the air inlet pipe.

[0007] The benefit of adopting the above technical solution is that the gas is introduced to the lower side of the liquid surface so that the gas coming out contains moisture, which is convenient for subsequent detection. The setting of the gas flow controller can detect the gas flow rate, and changing different gas flow rates can realize water absorption capacity detection under different conditions.

[0008] Furthermore, the end of the air inlet duct is sealed, and a plurality of air outlet holes are arranged on the side wall.

[0009] The advantage of adopting the above technical solution is that multiple air outlets allow the gas to fully contact with water.

[0010] Furthermore, the condenser is provided with a thermometer, a condensing coil is provided in the condenser, and the condensing coil is connected to the refrigeration device.

[0011] The benefit of adopting the above technical solution is that the thermometer is used to display the temperature inside the condenser, so that the temperature reaches the set value, and real-time detection is performed to ensure that the temperature meets the usage requirements. The setting of the condensing coil plays a cooling role, condensing part of the water in the gas to ensure that the water content of the gas reaches the set value, simulating different usage scenarios.

[0012] Furthermore, an air outlet pipe is provided on the upper side of the drying column, and a moisture meter, a back pressure valve and a pressure gauge are provided on the air outlet pipe.

[0013] The benefit of adopting the above technical solution is that the moisture meter is set to detect the moisture content. When the set value is reached, it is regarded as breakthrough and the adsorption process is completed, and then weighing is performed.

[0014] Furthermore, a pressure gauge before the condenser is provided on the first connecting pipeline, and a pressure gauge after the condenser is provided on the second connecting pipeline.

[0015] The benefit of adopting the above technical solution is that pressure gauges are set before and after the condenser to display the pressure before and after condensation, so as to realize water absorption monitoring under different pressures, and whether ice blockage occurs in the condenser can be judged by the change of pressure difference before and after the condenser.

[0016] Furthermore, a mesh demister is provided in the containing chamber, and the mesh demister is arranged 10 to 20 cm above the liquid surface.

[0017] The benefit of adopting the above technical solution is that it prevents fine droplets from entering the condenser along with the air flow, thereby ensuring that the water content of the gas reaches the required value.

[0018] Furthermore, the present application also discloses a method for testing the dynamic water adsorption capacity of a desiccant, using the desiccant dynamic water adsorption capacity testing device described in the above technical solution, comprising the following steps:

[0019] Step 1: setting the temperature of the refrigeration device, and starting the refrigeration device to cool the condenser (2) so that the temperature of the condenser reaches the corresponding dew point temperature;

[0020] Step 2: Set the back pressure value of the back pressure valve according to the working pressure of the working condition;

[0021] Step 3: Load the desiccant to be tested into the drying column, weigh the drying column before and after loading, and calculate the loading amount of the desiccant as m0, put it in the regeneration furnace and heat it with high-purity nitrogen for regeneration. After the regeneration is completed, wait for the drying column (3) to cool to room temperature, weigh the drying column, and record it as m1;

[0022] Step 4: Install the regenerated drying column onto the above-mentioned test device and perform an air tightness check;

[0023] Step 5: Calculate the gas flow rate according to the operating conditions and set the set value of the gas flow controller;

[0024] Step 6: After the temperature of the condenser reaches the set temperature, first open the valves other than the nitrogen source, then open the nitrogen source valve, start the desiccant drying performance test, and record the temperature of the condenser, the pressure before and after the condenser, the pressure of the drying column, and the water content after drying;

[0025] Step 7: When the water content of the dried gas is higher than the target value, it is considered to be penetrated and the test is over. First, close the nitrogen source valve, then close other valves in sequence according to the gas flow direction, turn off the refrigeration device, and purge the pipeline after the drying column with nitrogen;

[0026] Step 8: Disassemble the drying column, weigh it, and record it as m2;

[0027] Step nine: The dynamic adsorption capacity of the adsorbent under the current conditions can be calculated by the formula (m2-m1) / m0*100%.

[0028] Furthermore, before step 5, the pipeline after the drying column is purged with nitrogen until the water content does not change.

[0029] Furthermore, before performing step 1, the dew point temperature-water content table is consulted to determine the dew point temperature corresponding to the water content of the raw material, and the temperature of the refrigeration device is set according to the dew point temperature found.

[0030] The benefit of adopting the above technical solution is that it can realize the water absorption capacity test of the desiccant and realize the dynamic drying detection under different desiccants and different water content states. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0032] Figure 1 This is a schematic diagram of the connection of the desiccant dynamic water adsorption capacity test device of the present invention.

[0033] The reference numerals in the accompanying drawings are as follows:

[0034] Moisture generating device 1; gas flow controller 11; pressure gauge before condenser 12; first connecting pipe 13; air inlet pipe 14; condenser 2; thermometer 21; pressure gauge after condenser 22; second connecting pipe 23; condensing coil 24; drying column 3; pressure gauge 31; back pressure valve 32; air outlet pipe 33; moisture meter 4; mesh demister 15. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0036] like Figure 1 As shown, the present invention discloses a desiccant dynamic water adsorption capacity testing device, comprising a moisture generating device 1, a condenser 2 and a drying column 3 connected in sequence; the moisture generating device 1 is connected to a first connecting pipe 13 on the top thereof and connected to the lower end of the condenser 2; a containing chamber is arranged inside the moisture generating device 1, the containing chamber is filled with pure water, and an air inlet pipe 14 is connected to the upper side; the condenser 2 is connected to a refrigeration device; the condenser 2 is connected to the drying column 3 via a second connecting pipe 23; and the desiccant to be tested is placed in the drying column 3.

[0037] The benefit of adopting the above technical solution is that it can realize the water absorption capacity test of the desiccant and realize dynamic drying detection under different desiccants, different water content states and pressures.

[0038] In some embodiments, the end of the air inlet pipe 14 extends into the lower side of the liquid surface of the filling chamber, the end of the air inlet pipe 14 is sealed, and the side wall is provided with multiple air outlets. Nitrogen is introduced into the air inlet pipe 14, and the nitrogen enters below the pure water surface, so that it has a certain water content, which is used to test the desiccant and facilitate subsequent testing. Multiple air outlets allow nitrogen to fully contact with pure water.

[0039] Furthermore, the condenser 2 is provided with a thermometer 21 , which is arranged on the upper side of the condenser 2 to detect the internal temperature of the condenser 2 .

[0040] The benefit of adopting the above technical solution is that the thermometer is set to display the temperature in the condenser 2, so that the temperature reaches the set value, and is monitored in real time to ensure that the temperature meets the use requirements.

[0041] In some embodiments, a condenser coil 24 is provided in the condenser 2, and the condenser coil 24 is connected to a refrigeration device, which is a refrigerator, to control the internal temperature of the condenser 2. The condenser coil 24 is provided to cool the condenser 2, condense a portion of the water driven by the gas, reduce the water content of the entire gas, and simulate different usage scenarios.

[0042] Furthermore, an air outlet pipe 33 is provided on the upper side of the drying column 3, and a moisture meter 4, a back pressure valve 32 and a pressure gauge 31 are provided on the air outlet pipe 33, and a plurality of stop valves are also provided on the air outlet channel. The moisture meter 4 is used to detect the water content, and when the set value is reached, it is considered to be penetrated, the adsorption process is completed, and then weighing is performed.

[0043] Furthermore, a front-condenser pressure gauge 12 is provided on the first connecting pipe 13, and a rear-condenser pressure gauge 22 is provided on the second connecting pipe 23. Stop valves are provided on the rear side of the front-condenser pressure gauge 12 and the front side of the rear-condenser pressure gauge 22. The on-off of the first connecting channel and the second channel is controlled by the stop valves. The front-condenser pressure gauge 12 and the rear-condenser pressure gauge 22 detect the gas pressure before and after condensation.

[0044] The benefit of adopting the above technical solution is that pressure gauges are set before and after the condenser to display the pressure before and after condensation, so as to realize water absorption detection under different pressures, and whether ice blockage occurs in the condenser can be judged by the change of pressure difference before and after the condenser.

[0045] In some embodiments, a gas flow controller 11 is disposed on the gas inlet pipeline 14 , and shut-off valves are disposed on both sides of the gas flow controller 11 .

[0046] Furthermore, a mesh demister 15 is provided in the containing chamber, and the mesh demister 15 is arranged 10 to 20 cm above the liquid surface.

[0047] The benefit of adopting the above technical solution is that it prevents fine droplets from entering the condenser 2 along with the air flow, thereby ensuring that the water content of the gas reaches the required value.

[0048] Furthermore, the present application also discloses a method for determining the dynamic water adsorption capacity of a desiccant:

[0049] 1. Check the dew point temperature-water content table to determine the dew point temperature corresponding to the water content of the raw material;

[0050] 2. According to the dew point temperature found in the previous step, set the temperature of the refrigeration device (i.e., the ice machine), and start the ice machine to cool down the condenser 2 so that the temperature of the condenser 2 reaches the corresponding dew point temperature;

[0051] 3. Set the back pressure value of the back pressure valve 32 according to the working pressure of the working condition;

[0052] 4. Load the desiccant to be tested into the drying column 3, weigh the drying column 3 before and after loading, and calculate the loading amount of the desiccant (m0), put it into the regeneration furnace and heat it with high-purity nitrogen for regeneration. After the regeneration is completed, wait for the drying column 3 to cool to room temperature, weigh the drying column 3, and record (m1);

[0053] 5. Purge the pipeline after drying column 3 with nitrogen until the water content does not change;

[0054] 6. Install the regenerated drying column 3 onto the above-mentioned test device and perform an air tightness check;

[0055] 7. Calculate the gas flow rate according to the operating conditions and set the set value of the gas flow controller;

[0056] 8. After the temperature of condenser 2 reaches the set temperature, first open the valves other than the nitrogen source, then open the nitrogen source valve, start the desiccant drying performance test, and record the temperature of condenser 2, the pressure before and after condenser 2, the pressure of drying column 3, and the water content after drying;

[0057] 9. When the water content of the dried gas is higher than the target value, it is considered as breakthrough and the test is over. First, close the nitrogen source valve, then close other valves in the direction of gas flow, turn off the ice machine, and purge the pipeline after the drying column 3 with nitrogen;

[0058] 10. Disassemble the drying column 3, weigh it, and record it (m2);

[0059] 11. The dynamic adsorption capacity of the adsorbent under current conditions can be calculated by the formula (m2-m1) / m0*100%;

[0060] The moisture test result during the test is the drying effect of the adsorbent under the current conditions.

[0061] The device provided in the present application can test the adsorption capacity of a desiccant for water in gases with different water contents; it can also test the dynamic water adsorption capacity of a desiccant under different operating pressures.

[0062] Taking the test of 13X molecular sieve as an example, the specific process is as follows: Test the dynamic adsorption capacity of 13X molecular sieve for water content corresponding to the dew point temperature of 0°C, the drying pressure of 1barG, the flow rate of 1L / min, and the water content of the gas after drying is not higher than 5ppm.

[0063] The measuring device used includes: a gas flow controller 11, a moisture generating device 1, a condenser 2, a drying column 3, a back pressure valve 32, and a moisture meter 4.

[0064] Among them, the gas flow controller 11, the moisture generating device 1, the condenser 2, the drying column 3, the back pressure valve 32, and the moisture meter 4 are connected in sequence.

[0065] The moisture generating device 1 is filled with pure water. The end of the pipe inserted below the liquid surface is welded and sealed. Small circular holes are evenly opened on the inner wall of the pipe below 10 cm below the liquid surface. A mesh demister 15 is provided 10 cm above the liquid surface.

[0066] A stop valve is provided on the pipeline in front of the moisture generating device.

[0067] A coil is provided in the condenser 2, and a refrigerant flows through the coil. The refrigerant is supplied by an ice machine. The condenser 2 is insulated, and a temperature measuring point is provided on the upper part of the condenser.

[0068] Pressure gauges are provided between the moisture generating device 1 and the condenser 2 , between the condenser 2 and the adsorption column, and between the adsorption column and the back pressure valve 32 .

[0069] The testing process is:

[0070] 1. Set the temperature of the ice machine to 0℃.

[0071] 2. Set the back pressure value of the back pressure valve 32 to 1 bar;

[0072] 3. The activated 13X molecular sieve was loaded into the drying column 3 (volume 120 mL), with a total of 13X molecular sieve m0 = 80 g, and placed in the regeneration furnace for heating and regeneration with high-purity nitrogen. After the regeneration was completed, the drying column 3 was cooled to room temperature, and the drying column 3 was weighed and recorded (m1 = 783.6 g);

[0073] 4. Purge the pipeline after drying column 3 with nitrogen until the water content stabilizes at 0.2ppm;

[0074] 5. Install the regenerated drying column 3 onto the above-mentioned testing device and perform an air tightness inspection;

[0075] 6. Set the set value of the gas flow controller to 1L / min;

[0076] 7. After the temperature of condenser 2 stabilizes at 0°C, first open the valves other than the nitrogen source, then open the nitrogen source valve, and start the 13X molecular sieve dynamic water adsorption capacity test, record the temperature of condenser 2, the pressure before and after the condenser, the pressure of drying column 3, and the water content after drying, see test record table 1;

[0077] 8. When the water content of the dried gas is higher than 5ppm, it is considered as penetration and the test is over. First, close the nitrogen source valve, then close other valves in the direction of gas flow, turn off the ice machine, and purge the pipeline after the drying column 3 with nitrogen;

[0078] 9. Disassemble the drying column 3, weigh it, and record it (m2 = 801.44 g);

[0079] 10. The dynamic adsorption capacity of the adsorbent under the current conditions can be calculated to be 22.3% by the formula (m2-m1) / m0*100%;

[0080] 11. The moisture test result during the test is the drying effect of the adsorbent under the current conditions.

[0081] Desiccant dynamic water adsorption capacity test record table 1

[0082]

[0083]

[0084] For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, all of which fall within the protection scope of the present invention.

Claims

1. A desiccant dynamic water adsorption capacity testing device, characterized in that: The invention comprises a moisture generating device (1), a condenser (2) and a drying column (3) which are connected in sequence; the moisture generating device (1) is connected to the top with a first connecting pipe (13) which is connected to the lower end of the condenser (2); a containing chamber is arranged inside the moisture generating device (1), the containing chamber contains pure water and is connected to an air inlet pipe (14) on the upper side; the condenser (2) is connected to a refrigeration device; the condenser (2) and the drying column (3) are connected via a second connecting pipe (23); and a desiccant to be detected is placed in the drying column (3).

2. The desiccant dynamic water adsorption capacity testing device according to claim 1, characterized in that: The end of the air inlet pipe (14) extends into the lower side of the liquid surface of the containing chamber, and a gas flow controller (11) is arranged on the air inlet pipe (14).

3. The desiccant dynamic water adsorption capacity testing device according to claim 2, characterized in that: The end of the air inlet pipe (14) is sealed, and a plurality of air outlet holes are arranged on the side wall.

4. The desiccant dynamic water adsorption capacity testing device according to claim 1, characterized in that: The condenser (2) is provided with a thermometer (21), and a condensing coil (24) is provided inside the condenser (2), and the condensing coil (24) is connected to the refrigeration device.

5. The desiccant dynamic water adsorption capacity testing device according to claim 1, characterized in that: An air outlet pipe (33) is arranged on the upper side of the drying column (3), and a moisture meter (4), a back pressure valve (32) and a pressure gauge (31) are arranged on the air outlet pipe (33).

6. The desiccant dynamic water adsorption capacity testing device according to claim 1, characterized in that: The first connecting pipe (13) is provided with a pressure gauge (12) before the condenser, and the second connecting pipe (23) is provided with a pressure gauge (22) after the condenser.

7. The desiccant dynamic water adsorption capacity testing device according to claim 1, characterized in that: A mesh demister (15) is arranged in the containing chamber, and the mesh demister (15) is arranged 10 to 20 cm above the liquid surface.

8. A method for testing the dynamic water adsorption capacity of a desiccant, characterized in that: The desiccant dynamic water adsorption capacity testing device described in claims 1 to 7 above comprises the following steps: Step 1: setting the temperature of the refrigeration device, starting the refrigeration device, and cooling the condenser (2) so that the temperature of the condenser (2) reaches the corresponding dew point temperature; Step 2: Setting the back pressure value of the back pressure valve (32) according to the working pressure of the working condition; Step 3: Load the desiccant to be tested into the drying column (3), weigh the drying column (3) before and after loading, and calculate the loading amount of the desiccant as m0, put it into the regeneration furnace and heat it with high-purity nitrogen for regeneration. After the regeneration is completed, wait for the drying column (3) to cool to room temperature, weigh the drying column (3) and record it as m1; Step 4: Install the regenerated drying column (3) onto the above-mentioned test device and perform an air tightness inspection; Step 5: Calculate the gas flow rate according to the operating conditions and set the setting value of the gas flow controller (11); Step 6: After the temperature of the condenser (2) reaches the set temperature, first open the valves other than the nitrogen source, then open the nitrogen source valve, start the desiccant drying performance test, and record the temperature of the condenser (2), the pressure before and after the condenser (2), the pressure of the drying column (3), and the water content after drying; Step 7: When the water content of the dried gas is higher than the target value, it is considered to be breakthrough and the test is over. First, close the nitrogen source valve, then close other valves in sequence according to the gas flow direction, turn off the refrigeration device, and purge the pipeline after the drying column (3) with nitrogen; Step 8: Disassemble the drying column (3), weigh it, and record it as m2; Step nine: The dynamic adsorption capacity of the adsorbent under the current conditions can be calculated by the formula (m2-m1) / m0*100%.

9. The method for testing the dynamic water adsorption capacity of a desiccant according to claim 8, characterized in that: Before step 5, the pipeline after the drying column (3) is purged with nitrogen until the water content does not change.

10. The method for testing the dynamic water adsorption capacity of a desiccant according to claim 8, characterized in that: Before proceeding to step 1, consult the dew point temperature-water content table to determine the dew point temperature corresponding to the water content of the raw material, and set the temperature of the refrigeration device according to the dew point temperature found.

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