A method for evaluating catalyst activity

Abstract

The present invention relates to a method for quickly evaluating the reaction performance of a catalyst. The method uses the following catalyst evaluation device for detection, and the device includes: 1. a timer; 2. a low-temperature constant-temperature reaction bath; 3. a reaction chamber; (4) a first three-way valve (as an exhaust valve); (5) a second three-way valve; and 6. a metering area. The reaction pool is used to create harsh reaction conditions, and the rate of gas generated by the reaction of materials in the metering reaction chamber is used to measure the activity of the catalyst. The device is simple and convenient to operate, has a short cycle, and is highly efficient. The catalyst reaction performance evaluation method is suitable for catalytic reactions that generate gas during the reaction process, and requires less material samples, and is particularly suitable for reactions that generate expensive precious metal catalysts or toxic substances. In summary, the device can simply and quickly make a preliminary judgment on the activity of the catalyst and its applicable conditions.

Description

Technical Field

[0001] The present invention belongs to the field of chemical industry, and specifically relates to a method and device for evaluating catalyst activity. The device can accurately control the ambient temperature, simulate actual working conditions, and measure the catalyst activity by the gas generation rate of the reaction. Background Art

[0002] Catalysts are also called mediators. Catalysts are now widely used in most industrial processes such as aerospace, weapons and equipment. In the actual production process, there are many factors that affect the activity of the catalyst, such as the operating temperature of the catalyst, the type of additives in the catalyst, and the carrier used by the catalyst. For formed catalysts, the actual operating conditions of the catalyst will have a great impact on the activity of the catalyst. In severe cases, accidents may occur due to the loss of catalyst activity, such as shutdown or even explosion. Therefore, in actual work and production, due to the constant changes in the external environment and the huge temperature difference between cold and hot, whether the catalyst can still maintain its activity under harsh conditions is a prerequisite for the application of the catalyst.

[0003] Before the catalyst is used, it is necessary to simulate the working conditions of the catalyst to prevent the catalyst from being deactivated during its use. Pre-evaluating the catalyst and judging the applicable conditions of the catalyst are of great significance to the actual application of the catalyst. Summary of the invention

[0004] The purpose of the present invention is to establish a detection method and device that can quickly and accurately evaluate the activity of a catalyst. In general, the present invention has a simple structure and is easy to process. It uses a very small amount of sample to simulate the reaction conditions under different working conditions and judge the conditions for the use of the catalyst, which is of great significance for screening catalysts and their conditions for use. A method for quickly evaluating the reaction performance of a catalyst. It uses the following catalyst evaluation device to quickly detect the activity of the catalyst. The structure of the catalyst evaluation device includes: (1) a timer; (2) a low-temperature constant-temperature reaction bath; (3) a reaction chamber; (4) a first three-way valve (as an exhaust valve); (5) a second three-way valve; (6) a metering area.

[0005] (1) The timer has the functions of recording, zeroing and timing. The timing function starts at the beginning of the experiment. When data needs to be recorded, press the record button and the timing function is maintained until the entire experiment is completed. After transcribing the experimental data, reset to zero and stop timing. The time recording accuracy is ±0.01s

[0006] (2) The low-temperature constant temperature reaction bath includes stirring, temperature control and other functions. The temperature control tube is coiled on the wall around the reaction pool. The condensed solution circulates in the tube. The solution is driven by a compressor. A temperature measuring thermocouple is set at the bottom of the pool. The reaction pool contains ethylene glycol solution. A stirring rotor is set in the reaction pool to stir and mix the ethylene glycol solution to ensure that the temperature of the solution in the reaction pool is uniform and constant. The temperature control range of the reaction pool is within (-40~25)±0.1℃.

[0007] (3) The reaction chamber consists of three areas. Chamber A is equipped with an air outlet and is connected to the metering area. Chambers B and C are used to hold materials. The three chambers are connected to the main body by threads.

[0008] (4) The metering area consists of a large-capacity U-shaped tube (E) and a small-capacity U-shaped tube (F), which are marked with accurate scales and contain a certain amount of liquid. Under normal pressure, the liquid on the left and right sides of the U-shaped tube maintain the same liquid level. When gas is generated in the device, a liquid level difference appears on the left and right sides of the U-shaped tube under the action of the pressure difference. The difference can be considered as the amount of gas generated in the reaction.

[0009] Before the experiment begins, open the 4 exhaust valves to ensure that the left and right liquid levels of the U-shaped tube are level. B warehouse and C warehouse body are loaded with catalyst and reaction liquid respectively, fix the 3 reaction warehouse on the clip in the 2 low temperature constant temperature reaction bath, immerse the 3 reaction warehouse in the ethylene glycol in the reaction tank, ensure that the B and C warehouse bodies are below the liquid surface, cool the reactants to the required test temperature, and keep them for a period of time, then close the 4 exhaust valves, rotate the 3 reaction warehouse to a certain angle, and make the materials mixed and reacted. The reaction produces gas, turn the 5 three-phase valve to the E metering area, and preliminarily measure the gas generation rate to prevent liquid from being flushed due to violent reaction; when the gas generation rate is greater than 240ml / h, use the E metering area for accurate measurement. When the gas generation rate is less than 240ml / h, turn the three-phase valve to the F metering area for accurate measurement. Calculate the gas generation rate generated by the reaction of unit mass catalyst to determine the reaction activity of the catalyst at this temperature. After the experiment, open the exhaust valve to discharge the excess gas in the device to ensure that the left and right liquid levels in the U-shaped tube in the metering area are level.

[0010] The catalyst reaction activity is calculated by calculating the volume of gas produced by the catalyst per unit time. The formula is as follows:

[0011]

[0012] S = gas production per unit mass of catalyst per unit time, ml / (mg*h);

[0013] V = volume of gas produced by one-side reaction, ml;

[0014] m = mass of the catalyst involved in the reaction, mg;

[0015] t = evaluation reaction time, h.

[0016] The present invention uses a reaction pool to create harsh reaction conditions, and uses the rate of gas generated by the reaction of materials in the metering reaction chamber to measure the catalyst activity. The device is simple and convenient to operate, has a short cycle, and is highly efficient. The catalyst reaction performance evaluation method is suitable for catalytic reactions that generate gas during the reaction process, and requires less material samples, and is particularly suitable for reactions involving expensive precious metal catalysts or those that generate toxic substances. In summary, the device can simply and quickly make a preliminary judgment on the catalyst activity and its applicable conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A diagram of a catalyst activity evaluation device, 1. timer, 2. low-temperature constant-temperature reaction bath (the one used in the present invention is DHJF-4010 from Zhengzhou Great Wall Science & Industry & Trade Co., Ltd.), 3. reaction chamber, 4. first three-way valve (as exhaust valve); 5. second three-way valve, 6. metering area;

[0018] Figure 2 Exploded view of the reaction chamber, A, gas outlet area, B, catalyst placement area, C, reaction liquid placement area;

[0019] Figure 3 Summary graph of test results. DETAILED DESCRIPTION

[0020] The present invention is described in detail below through specific examples, but these examples do not limit the contents of the present invention.

[0021] A method for evaluating catalyst reaction performance, which uses the following catalyst evaluation device to detect catalyst activity, wherein the catalyst evaluation device structure includes: (1) a timer; (2) a low-temperature constant-temperature reaction bath; (3) a reaction chamber; (4) a first three-way valve (as an exhaust valve); (5) a second three-way valve; (6) a metering area;

[0022] The metering area includes two U-shaped tubes with two ends open. The two U-shaped tubes have different capacities, namely, a large-capacity U-shaped tube E and a small-capacity U-shaped tube F.

[0023] The reaction chamber includes three closed cylindrical containers with one end open, namely chamber A, chamber B, and chamber C;

[0024] The opening ends of the three sealed cylindrical containers are respectively connected to an interface of a three-way connection, and an air outlet is provided on the wall of warehouse A away from its opening end.

[0025] The A bin is fixedly connected or screwed and sealed to one interface of the tee, and the B bin and the C bin are screwed and sealed to one interface of the tee through threads respectively; one of the B bin and the C bin is used to hold the catalyst, and the other is used to hold all other reaction materials except the catalyst;

[0026] The air outlet of the A warehouse is connected to an interface (as an air inlet) of the second three-way valve 5 through a pipeline via the first three-way valve 4, and the other two interfaces of the second three-way valve 5 are respectively connected to one open end of the large-capacity U-shaped tube E and the small-capacity U-shaped tube), and the other open ends of the large-capacity U-shaped tube E and the small-capacity U-shaped tube F are respectively vented (connected to the atmosphere); the third interface of the first three-way valve 4 is vented (connected to the atmosphere);

[0027] The low-temperature constant-temperature reaction bath is filled with ethylene glycol solution;

[0028] The process of detecting the activity of the catalyst:

[0029] 1) Catalyst and all other reaction materials except the catalyst are loaded into bin B and bin C respectively, bin A is sealed and connected to one interface of the tee, and bin B and bin C are detachably and sealedly connected to one interface of the tee respectively;

[0030] Put liquid into the large-capacity U-shaped tube E and the small-capacity U-shaped tube F;

[0031] 2) Rotate the first three-way valve 4 to connect the air inlet of the second three-way valve 5 to the atmosphere; rotate the second three-way valve 5 to make the liquid levels at the two opening ends of the large-capacity U-shaped tube E and the small-capacity U-shaped tube F on the same horizontal plane;

[0032] 3) Place the reaction chamber above the ethylene glycol solution in the low-temperature constant-temperature reaction bath, with chamber A located above chambers B and C; immerse all or part of the reaction chamber in the ethylene glycol solution in the reaction bath, ensuring that chambers B and C are located below the liquid surface, and cool the reactants to the desired temperature;

[0033] 4) Rotate the first three-way valve 4 to connect the air inlet of the second three-way valve 5 to the reaction chamber, and rotate the second three-way valve 5 to connect the air inlet to an open end of the large-capacity U-shaped tube E;

[0034] 5) Rotate the reaction chamber to mix the materials in chambers B and C; start timing with timer 1 at the same time, measure the volume of gas produced by E after a period of time, and then calculate the gas production rate, so as to judge the reaction activity of the catalyst at this temperature. If the reaction is stable (meaning that the liquid level at the open end of the large-capacity U-shaped tube E away from the air inlet of the second three-way valve 5 rises uniformly or decreases), and the gas production rate is less than 240ml / h, rotate the second three-way valve 5 so that its air inlet is connected to an open end of the small-capacity U-shaped tube F;

[0035] At the same time, timer 1 is restarted. After a period of time, the volume of gas produced by F is measured, and then the gas production rate is calculated to determine the reaction activity of the catalyst at this temperature.

[0036] By measuring the height change of the liquid level between the two open ends of the small-capacity U-shaped tube, the volume of the gas entering the small-capacity U-shaped tube and the ratio of the gas volume to time and catalyst mass (ml / (mg*h)) are calculated.

[0037] A clamp for fixing the reaction chamber 3 is provided above the ethylene glycol solution in the low-temperature constant-temperature reaction bath;

[0038] The low-temperature constant temperature reaction bath includes stirring, temperature control and other functions. The reaction pool contains (50wt%) ethylene glycol aqueous solution, and a stirring rotor is provided in the reaction pool to stir and mix the ethylene glycol solution to ensure that the temperature of the solution in the reaction pool is uniform and constant; the temperature control range of the reaction pool is within (-40~25)±0.1℃;

[0039] The A chamber is fixedly connected to an interface of the tee or is screwed and sealed through a thread, and the B chamber and the C chamber are screwed and sealed through a thread respectively with an interface of the tee.

[0040] The metering area consists of a large-capacity U-tube E and a small-capacity U-tube F. The side walls of the U-tubes are marked with accurate scales and filled with water. Under normal pressure, the liquid on the left and right sides of the U-tubes maintain the same liquid level. When gas is generated in the device, a liquid level difference appears on the left and right sides of the U-tube under the action of the pressure difference. The difference can be considered as the amount of gas generated in the reaction.

[0041] The timer has recording, zeroing and timing functions. The timing function starts at the beginning of the experiment. When data needs to be recorded, press the record button and the timing function is maintained until the entire experiment is completed. After transcribing the experimental data, reset to zero and stop timing. The time recording accuracy is ±0.01s.

[0042] The device measures the activity of the catalyst by accurately measuring the amount of gas produced in a certain period of time for catalytic reactions with gas production.

[0043] Before and after the experiment, the exhaust valve should be opened, and the first three-way valve 4 should be rotated to connect the air inlet of the second three-way valve 5 to the atmosphere, ensuring that the liquid levels on the left and right sides of the U-shaped tube in the metering area are level;

[0044] If toxic gas is generated during the experiment, a gas recovery device should be installed at the third interface of the first three-way valve 4 to collect the toxic gas.

[0045] A hose is provided at the outlet of the reaction chamber (the outlet of chamber A) and connected to the first three-way valve 4 to facilitate the rotation of the reaction chamber. The angle between the normal lines of the three interface planes of the three-way valve is 120°.

[0046] The range of the large-capacity U-tube (E) is 300 ml;

[0047] The range of the small-capacity U-tube (F) is 30 ml;

[0048] Example 1

[0049] Take 0.02g of alumina-loaded ruthenium precious metal catalyst and place it in chamber B, put 3g of hydrazine nitrate propellant in the reaction liquid into chamber C, fix chamber A to one interface of the tee or screw and seal it, and chamber B and chamber C are screwed and sealed to one interface of the tee respectively through threads; fix chamber 3 on the clamp in low-temperature constant-temperature reaction bath 2, immerse chamber 3 in the ethylene glycol solution in the reaction tank, ensure that chambers B and C are below the liquid surface, cool the reactants to -30°C, and keep it for 30 minutes.

[0050] The air outlet of warehouse A is connected to an interface (as an air inlet) of the second three-way valve 5 through a pipeline via the first three-way valve 4. The other two interfaces of the second three-way valve 5 are respectively connected to an open end of the large-capacity U-shaped tube E and the small-capacity U-shaped tube F. The other open ends of the large-capacity U-shaped tube E and the small-capacity U-shaped tube F are respectively vented (connected to the atmosphere); the third interface of the first three-way valve 4 is vented (connected to the atmosphere). Rotate the first three-way valve 4 to connect the air inlet of the second three-way valve 5 to the atmosphere; ensure that the liquid levels on the left and right sides of the U-shaped tube in the metering area are level.

[0051] Rotate the first three-way valve 4 to connect the air inlet of the second three-way valve 5 to the reaction chamber, and rotate the second three-way valve 5 to connect the air inlet to an open end of the large-capacity U-shaped tube E; rotate the 3 reaction chamber to make the reaction chamber B vertically downward to make the materials mixed and reacted. At the same time, use timer 1 to start timing. After timing for a period of time, measure the volume of gas produced by E, and then calculate the gas generation rate to determine the reaction activity of the catalyst at this temperature. If the gas generation rate is less than 240ml / h when the reaction is stable, rotate the second three-way valve 5 to connect the air inlet to an open end of the small-capacity U-shaped tube F, and at the same time, press the timing function of the 1 timer to restart the timing, start the timing function to start timing, press the record key when data needs to be recorded, and keep the timing function until the entire experiment is completed. After copying the experimental data, return to zero, stop timing, calculate the gas generation rate, and determine the reaction activity of the catalyst at this temperature. After the experiment is over, open the exhaust valve to discharge the excess gas in the device to ensure that the left and right liquid levels in the U-shaped tube in the metering area are level. After testing, the catalyst produced gas at a rate of 0.229 ml / (mg*h) per unit mass of catalyst at -30°C.

[0052] Example 2

[0053] The process and conditions are the same as those in Example 1, except that the reactants are cooled to -20°C and the decomposition gas production data are recorded. After testing, the catalyst has a gas production rate of 1.514 ml / (mg*h) at -20°C.

[0054] Example 3

[0055] The process and conditions are the same as those in Example 1, except that the reactants are cooled to -10°C and the decomposition gas production data are recorded. After testing, the catalyst has a gas production rate of 6.2 ml / (mg*h) at -10°C.

[0056] Example 4

[0057] The process and conditions are the same as those in Example 1, except that the reactants are cooled to 0°C and the decomposition gas production data are recorded. After testing, the catalyst has a gas production rate of 25 ml / (mg*h) at 0°C.

[0058] Example 5

[0059] The process and conditions are the same as those in Example 1, except that the reactants are cooled to 10° C. and the decomposition gas production data are recorded. After testing, the catalyst has a gas production rate of 52.25 ml / (mg*h) at 10° C.

[0060] The catalyst activity evaluation device of the present invention simulates different ambient temperatures to analyze the activity of the catalyst. The test data is shown in Figure 3 .

Claims

1. A method for evaluating catalyst reaction performance, which uses the following catalyst evaluation device to detect catalyst activity, and the catalyst evaluation device structure includes: Timer (1); low-temperature constant-temperature reaction bath (2); reaction chamber (3); first three-way valve (4); second three-way valve (5); metering area (6); The metering area includes two U-shaped tubes with two ends open. The two U-shaped tubes have different capacities, namely a large-capacity U-shaped tube (E) and a small-capacity U-shaped tube (F). The reaction chamber includes three closed cylindrical containers with one end open, namely chamber A, chamber B, and chamber C; The opening ends of the three sealed cylindrical containers are respectively connected to an interface of a three-way connection, and an air outlet is provided on the wall of warehouse A away from its opening end. The A bin is fixedly connected or screwed and sealed to one interface of the tee, and the B bin and the C bin are screwed and sealed to one interface of the tee through threads respectively; one of the B bin and the C bin is used to hold the catalyst, and the other is used to hold all other reaction materials except the catalyst; The air outlet of the A chamber is connected to an interface of the second three-way valve (5) through a pipeline via the first three-way valve (4) as an air inlet, and the other two interfaces of the second three-way valve (5) are respectively connected to one open end of the large-capacity U-shaped tube (E) and the small-capacity U-shaped tube (F), and the other open ends of the large-capacity U-shaped tube (E) and the small-capacity U-shaped tube (F) are respectively connected to the atmosphere; the third interface of the first three-way valve (4) is connected to the atmosphere; The low-temperature constant-temperature reaction bath is filled with ethylene glycol solution; The process of detecting the activity of the catalyst: 1) Catalysts and all other reaction materials except catalysts are loaded into bins B and C respectively, bin A is sealed and connected to one interface of the tee, and bins B and C are detachably and sealedly connected to one interface of the tee respectively; Put liquid into the large-capacity U-shaped tube (E) and the small-capacity U-shaped tube (F); 2) rotating the first three-way valve (4) so ​​that the air inlet of the second three-way valve (5) is connected to the atmosphere; by rotating the second three-way valve (5), the liquid levels at the two opening ends of the large-capacity U-shaped tube (E) and the small-capacity U-shaped tube (F) are respectively on the same horizontal plane; 3) Place the reaction chamber above the ethylene glycol solution in the low-temperature constant temperature reaction bath, with chamber A located above chambers B and C; Immerse all or part of the reaction chamber into the ethylene glycol solution in the reaction tank, ensure that chambers B and C are below the liquid surface, and cool the reactants to the required temperature; 4) rotating the first three-way valve (4) so ​​that the air inlet of the second three-way valve (5) is connected to the reaction chamber, and rotating the second three-way valve (5) so that the air inlet is connected to an open end of the large-capacity U-shaped tube (E); 5) rotating the reaction chamber to mix and react the materials in chambers B and C; after the reaction becomes stable, rotating the second three-way valve (5) to connect its air inlet to an open end of the small-capacity U-shaped tube (F); stable reaction means that the liquid level at the open end of the large-capacity U-shaped tube (E) away from the air inlet of the second three-way valve (5) rises uniformly or decreases; At the same time, a timer (1) is used to start timing. After a period of time, the volume of gas generated by the small-capacity U-tube (F) is measured, and the gas generation rate is calculated to determine the reaction activity of the catalyst at this temperature.

2. The evaluation method according to claim 1, characterized in that : By measuring the height change of the liquid level between the two open ends of the small-capacity U-shaped tube, the volume of the gas entering the small-capacity U-shaped tube and the ratio of the gas volume to time and catalyst mass (ml / (mg*h)) are calculated.

3. The evaluation method according to claim 1, characterized in that: A clamp for fixing the reaction chamber (3) is arranged above the ethylene glycol solution in the low-temperature constant-temperature reaction bath; The low-temperature constant-temperature reaction bath includes stirring, temperature control and other functions. The reaction pool contains 40wt%~60wt% ethylene glycol aqueous solution. The reaction pool is equipped with a stirring rotor to stir and mix the ethylene glycol solution to ensure that the temperature of the solution in the reaction pool is uniform and constant; the temperature control range of the reaction pool is within (-40~25)±0.1℃; The A chamber is fixedly connected to an interface of the tee or is screwed and sealed through a thread, and the B chamber and the C chamber are screwed and sealed through a thread respectively with an interface of the tee.

4. The evaluation method according to claim 1, characterized in that: The metering area is composed of a large-capacity U-shaped tube (E) and a small-capacity U-shaped tube (F). The side wall of the U-shaped tube is marked with accurate scales and filled with water. Under normal pressure, the liquid on the left and right sides of the U-shaped tube maintain the same liquid level. When gas is generated in the device, a liquid level difference appears on the left and right sides of the U-shaped tube under the action of pressure difference. The difference can be considered as the amount of gas generated in the reaction; The timer has recording, zeroing and timing functions. The timing function starts at the beginning of the experiment. When data needs to be recorded, press the record button and the timing function is maintained until the entire experiment is completed. After transcribing the experimental data, reset to zero and stop timing. The time recording accuracy is ±0.01s.

5. The evaluation method according to claim 1, characterized in that: The device measures the activity of the catalyst by accurately measuring the amount of gas produced in a certain period of time for catalytic reactions with gas production. The amount of catalyst loaded and consumed in the device is in the range of (0.01~0.1) g.

6. The evaluation method according to claim 1, characterized in that: Before and after the experiment, the exhaust valve should be opened, and the first three-way valve (4) should be rotated to connect the air inlet of the second three-way valve (5) to the atmosphere, ensuring that the liquid levels on the left and right sides of the U-shaped tube in the metering area are level; If toxic gas is generated during the experiment, a gas recovery device should be installed at the third interface of the first three-way valve (4) to collect the toxic gas.

7. The evaluation method according to claim 1, characterized in that: The measuring range of the large-capacity U-tube (E) in the metering area should be more than 10 times the measuring range of the small-capacity U-tube (F) to prevent the liquid in the U-tube from rushing out due to violent reaction in the early stage of the reaction; Preliminary measurement of the gas generation rate was performed to prevent liquid flushing due to violent reaction. When the measured gas generation rate was less than 240 ml / h, the reaction was considered stable.

8. The evaluation method according to claim 1, characterized in that: A section of hose is provided at the air outlet of the reaction chamber, i.e., the air outlet hole of chamber A, and is connected to the first three-way valve (4) to facilitate the rotation of the reaction chamber.

9. According to the evaluation method of claim 1, the angle between the normal lines of the two interface planes connecting the tee in the reaction chamber to the B chamber and the C chamber is in the range of 105° to 135°, which can prevent the reactants from being mixed prematurely due to vibration of the surrounding environment when the angle is too large, and prevent the material mixing from being hindered due to a small angle.

10. The evaluation method according to claim 1 or 9, characterized in that: The angle between the normal lines of the three interface planes of the tee is 105°~135°.

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