Who knows how the catalyst wear index is defined?

Definition: The wear index is the percentage of the weight of the fine powder with a size of less than 15 microns, generated after subjecting a certain amount of microsphere catalyst to high-speed airflow for 4 hours, relative to the weight of the catalyst particles with a size greater than 15 microns.

The catalyst is placed in a specific instrument, and after being subjected to high-speed airflow for 4 hours, the percentage of the fine powder with a size of less than 15 microns relative to the weight of the catalyst with a size of more than 15 microns constitutes the catalyst wear index. The catalyst wear index is generally in the range of 2-5. There are two methods for determining the wear index of cracking catalysts: the gooseneck tube method and the straight tube method, with the data obtained using the straight tube method generally being higher than those obtained using the gooseneck tube method.

As the vibration problem of the flue gas extractor is suspected to be related to the catalyst, CNPC is researching ways to reduce the wear index

A certain amount of catalyst is placed in a device used to measure the wear index. After being subjected to a constant airflow for 5 hours, the samples smaller than 15 microns that are emitted during the first hour are discarded. The samples emitted over the subsequent 4 hours are collected, and the average wear percentage per hour is calculated (as the percentage of the weight of samples smaller than 15 microns emitted per hour relative to the weight of the catalyst particles larger than 15 microns). This value is known as the catalyst wear index, and its unit is %/h. The lower the wear index, the better the anti-wear performance of the catalyst.

XII. Determination of wear index (straight tube method) 1. Subject matter and scope: This standard specifies the method for determining the wear index of petroleum refining catalysts using a straight tube. This standard is applicable to the determination of the fluidized wear performance of petroleum refining catalysts. 2 Method Summary A certain amount of sample is placed in the wear index testing apparatus and subjected to abrasion at a constant air flow rate for five hours. The samples blown out during the first hour are discarded; for the samples blown out within the subsequent four hours, the average wear percentage per hour is calculated to serve as the wear index of the sample. 3 Instrumentation and Equipment 3.1 Wear index analyzer: The main components and process are shown in Figure 1. 1 Valve F1 2 Pressure gauge P 3 Settler Dp 4 Vent valve F3 5 Humidifier 6 Pressure gauge PH 7 Control valve F2 8 Rotameter 9 Diaphragm pressure gauge 10 Straight pipe 11 Settling chamber 12 Filter paper cartridge 3.2 Straight pipe: φ25mm×440mm, nozzle inner diameter 1mm ； 3.3 Latex drainage tube: semi-circumference 40mm ； 3.4 Wet-type flow meter: 5L ； 3.5 Analytical balance: sensitivity of 0.001g ； 3.6 Volumetric flask: 50mL ； 3.7 Clock Setting ； 3.8 Rubber stopper: 7# ； 3.9 Filter paper cylinder: φ35mm×110mm ； 3.10 Evaporating dish: 200mL ； 3.11 High-temperature furnace: 0-1000℃ ； 3.12 Drier: φ150mm, with color-changing silica gel as the desiccant. 4 Analysis Steps 4.1 Preparation 4.1.1 Take approximately 35 g of the sample and place it in an evaporating dish; then burn it in a furnace at 540±14°C for 3 hours. Remove it, cool it in air for 5 minutes, then place it in a desiccator to cool to room temperature for later use. 4.1.2 Add water to the humidifier until the level reaches 150 mm. 4.1.3 Check the water level and levelness of the wet flow meter. 4.1.4 Securely connect the filter paper cylinder to the outlet of the sedimentation chamber using a rubber stopper, and cover it with a 30 mm long drainage tube to prevent the filter paper cylinder from falling. Blow for 15 minutes under the operating flow rate and humidification pressure to achieve a constant weight. After 15 minutes, close valve F2, open valve F3 for venting, and finally close valve F1. Remove the filter paper cartridge, weigh it quickly, and record the mass. Note: If the filter paper cartridge is reused, it is not necessary to determine its constant weight again. After cleaning up following the first test, the mass can be weighed and recorded promptly for use in subsequent trials. 4.1.5 Connect the apparatus using normal procedures; do not install the sample or filter paper cartridge, and block the outlet of the sedimentation chamber. Close valve F3, open valves F1 and F2 to raise the system pressure to 24.5 KPa, then close valve F2. If the pointer on the system pressure gauge does not move within 2 minutes, it indicates that the device is leak-free. If it drops. This indicates that there is a leak in the device; a thorough inspection and adjustment of the device are required until no leaks remain in the system. Then reduce the system pressure to zero. 4.1.6 Connect the testing apparatus; do not install the sample and filter paper cartridge yet, and connect the outlet of the sedimentation chamber to the wet flow meter in order to calibrate the rotameter. Open the inlet valve F1, use the control valve F2 to adjust the air flow to the desired rate, note the height of the float in the rotameter; during the measurement process, the flow rate is controlled based on the height of the float in the rotameter. This method has strict requirements regarding flow rate; the flow rate must be calibrated each time a sample is prepared. 4.2 Calibration of straight pipes: Straight pipes are calibrated using standard samples with known wear indices, following the same method as that used for testing samples; the error across three consecutive measurements shall not exceed ±5%. 4.3 Sample determination 4.3.1 Weigh about 10 g of the treated sample using a 50 mL weighing vessel, with an accuracy of 0.002 g. Add 0.5 mL of distilled water to the sample using a dropper, stir gently with a glass rod being careful to break up any particles, and set it aside for use. 4.3.2 Transfer the weighed sample ready for use into the straight tube. After reaching a constant weight, the filter paper cylinder is placed on the rubber stopper at the top of the sedimentation chamber, with a drainage tube attached to it to ensure a tight connection between the two. .4.3.3 Close valve F3, open valve F1, then open valve F2, and record the start time of the experiment. Adjust the flow rate to 21.0±0.2 L/min, set the humidification pressure at 0.06±0.002 MPa, and tap the sedimentation chamber thoroughly once. At 5 minutes into the experiment, the sedimentation chamber was tapped thoroughly once again; at 15 minutes, it was tapped thoroughly once more. Thereafter, it was tapped thoroughly every 15 minutes. Attention was also paid to maintaining the rotor’s height. After 1 hour, valve F2 was closed, the filter paper cylinder was removed, weighed quickly, and its mass was recorded. The sample was then poured out, and the cylinder was weighed again to determine its mass m1 for the subsequent 4 hours. 4.3.4 Reinstall the weighed filter paper cylinder in its original position, set the flow rate to 21.0±0.2 L/min and the humidification pressure to 0.06±0.002 MPa. Note down the start time, maintain these conditions, and carry out the scouring process for 4 hours; the sedimentation chamber should be tapped thoroughly every 30 minutes. 4.3.5 10 minutes before the end of the test, the sedimentation chamber should be tapped thoroughly once; thereafter, attention should be paid at all times to tapping the glass tube at the outlet of the sedimentation chamber to prevent any material from remaining there. 4.3.6 After 4 hours of testing, stop knocking. Turn off F2, turn on F2, and finally turn off F1. Remove the filter paper cylinder, weigh it quickly with an accuracy of 0.002 g, and record the mass as m2. Then tap the sedimentation chamber thoroughly to collect all the sample adhering to the walls into the straight tube; subsequently, transfer the sample in the straight tube to a 50 mL weighing flask and weigh it (with an accuracy of 0.002 g), recording the mass as m3. 5 Calculate AI = ×100 / (a+b)×4. Here, AI is the wear index, in %h-1 ； a Mass of samples smaller than 15 μm collected in the filter paper tube over the next 4 hours, in g ； a = m2 – m1 ； b Mass of the sample inside the straight tube, g ； b = m3 – m0 ； m0: Mass of the weighing flask, in g ； Mass of the filter paper cylinder after humidification, in g ； Mass of samples smaller than 15 μm after 4 hours of blowing and grinding using M2 filter paper tubes, in grams ； Mass of the m3 weighing vessel for samples larger than 15 μm, in g. 6 Allowance: The relative deviation between two parallel test results shall not be greater than 15%. 7. The result is reported as the arithmetic mean of the two results from parallel tests, expressed with two significant figures.

A certain amount of microsphere catalyst is placed in a specific instrument, and after being subjected to high-speed airflow for 4 hours, the percentage of the fine powder with a size of less than 15 microns relative to the weight of the catalyst particles larger than 15 microns constitutes the wear index. This is the definition; nothing else is clear

Thank you all for your replies; they have been extremely helpful to me.

Reply to 6# chjtao11: Where can I buy this type of testing instrument? Which company offers the best ones? Thank you!

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