What should be considered when loading a catalyst?

Loading of the conversion catalyst: The loading of nickel catalyst is a very important, careful, and precise task. To ensure that the process gas is distributed evenly throughout each conversion tube, it is necessary to avoid any blockages or bridging within each tube. It is particularly important to prevent low flow in any of the conversion tubes, as excessive oscillation, catalyst breakdown, or blockages in the catalyst trays or pigtail pipes can all lead to low flow. Operating under such conditions can cause overheating or localized overheating of the furnace tubes, thereby shortening the service life of the conversion tubes and affecting normal production. (1) Tools required for loading: 2 measuring sticks, 2 scales, 1 pressure difference measuring device, 2 oil gauges (20m length), 100 canvas bags (φ85×1600), 2 loading funnels and funnel stands each, 1 winch, 2 screens, 48 conversion tube covers, 2 flashlights, 2 hammers (8 pounds), 2 pieces of 20m nylon rope, new maintenance uniforms (one set per participant), 4 hooks, 2 fixed pulleys, 1 large piece of canvas, safety goggles, magnets, a small telescope, etc. (2) Preparatory work before loading — Organize employees to study the loading plan. ——Organize the personnel properly: appoint a chief responsible person, and assign individuals to handle tasks such as catalyst transportation, weighing, screening, selection, measurement, bagging, lifting, filling, shaking, height measurement, recording, and safety measures. ——Inspection and measurement of the conversion tube: a. Inspect and purge the conversion tube to ensure that no debris remains inside the tube or on the catalyst tray. b. Measure the air tube pressure difference and determine the average value. The pressure difference in air control should be within ±0.5% of the average value, and detailed records should be kept to ensure that the holes in the tray are unobstructed. c. Measure the height of the air duct (from the tray to the flange surface of the conversion tube) and record it. (3) Catalyst loading: The catalyst for conversion is loaded in two types – long rings and short rings. The volume of catalyst used for short rings is 2.27 m3, and the same volume is used for long rings. The specific loading weight depends on the type of catalyst chosen. Calculation: Given a filling volume of 4.54 m3 and 48 conversion tubes, with dimensions of φ124/φ100, the filling volume per tube is 0.0945833 m3, and the filling height is 12,050 mm. First, install the long rings; depending on the catalyst chosen, the filling height for each half of the tube is 6025 mm. If 7 barrels are used, the net height of each barrel is 860 mm, and its volume is 0.006751 m3. The weight of material to be filled in each barrel is determined by referring to the density of the catalyst being used. For the rear-mounted short rings, depending on the catalyst used, the filling height for each ring is 6025 mm; if 7 barrels are used, the net height of each barrel is 860 mm and its volume is 0.006751 m3. The filling weight per barrel is determined by referring to the bulk density of the catalyst used earlier. Filling: a. First, insert the long rings; after one bucket is placed in each tube, measure the filling height, then shake it and measure the height again. Record these values, calculate the average filling height, and compare this average with the height of filling per bucket in each tube. If the error is less than 30 mm, it is considered acceptable; if it is greater than 30 mm, shaking the tube and measuring the height again is necessary to eliminate any bridging effects. If the result is still not satisfactory, the contents must be removed and reinserted. b. Fill 6 barrels (i.e., 12 bags) with long rings using the same method as for the first barrel, and adjust the filling height of each tube to 6025 ± 30 mm. c. After loading the long ring, measure the resistance of the semi-tube catalyst layer once and record the value to obtain an average value. If the measured value falls within ±5% of the average value, it is considered acceptable; if the deviation is above +5%, the catalyst needs to be removed and reinstalled; if the deviation is below -5%, more catalyst should be added and the mixture shaken. Redetermine the pressure difference until all are qualified. d. Then load the short ring using the same method as loading the long ring. e. After filling 7 barrels (14 bags), the final adjusted loading height should be 730±30 mm from the furnace tube flange surface. (4) Measurement of pressure difference – Measurement of the pressure difference in the main pipe: a. Check the measuring instruments to ensure there are no leaks; prepare instrument air and maintain a gas supply pressure of >0.5 MPa(G), while keeping the outlet of the converter unobstructed. b. Open the air valve to stabilize the primary pressure at 0.5 MPa(G); pass air through for three minutes to purge the catalyst layer, and record the secondary pressure (behind the orifice plate). b. Calculate the average value of the secondary pressure across the 48 conversion tubes. Compare the measured values with this average; if the deviation is within ±5%, it is considered acceptable. If the deviation is above +5%, the tubes need to be removed and reinstalled. If the deviation is below -5%, more catalyst should be added, the mixture shaken, and the pressure difference measured again. Measurement of the pressure difference in the pigtail pipes: a. The measurement of the pressure difference in the lower pigtail pipes is carried out simultaneously with that of the pressure difference in the empty pipes. The measurement method is the same as that used for measuring the pressure difference in the actual pipes. Finally, the average value of the secondary pressures of all 48 pigtail pipes is calculated. If the measured value falls within ±10% of this average value, it is considered acceptable; if the deviation exceeds 10%, corrective actions must be taken until all values are within the acceptable range. Then, the upper flange is installed. b. After the catalyst has been loaded, measure the pressure in the pigtail tube; (the expansion ring must not be inserted below the pigtail tube), using the same method as for measuring the pressure difference in regular tubes. (5) After achieving airtightness and passing the purging test, fill with N2 for protection and wait for temperature rise for reduction. (6) Precautions: —— When screening the nickel catalyst, be sure to remove any broken or damaged pieces. ——During loading, handle it gently; do not drop it suddenly, and take care to prevent the catalyst from leaking out from the upper part of the furnace tube. ——Keep detailed records of the filling process; the catalyst should be filled on a sunny day. ——The entire process should be carried out strictly in accordance with the loading plan.

Before installing the tower, it should be purged to remove any possible contaminants. Check the integrity and adequacy of the support. Check the catalyst’s model and strength, and verify whether it is damp. Try to avoid loading on rainy days. The catalyst is sieved to remove fine powder, and after weighing, it is loaded into the tower in batches. The filling must be tight and even. Throughout the loading process, efforts should be made to prevent contamination by water, oil, and other contaminants. Each batch of catalyst should be leveled promptly to avoid having to level it again after it has risen. Prevent larger particles from slipping to the edges. It is not allowed to step directly on the catalyst; a larger wooden board can be used as a footrest. During loading, it is necessary to control the loading density in a timely manner. For towers with a high bed height, metal chutes can be used to load material at different levels, and their heights can be measured continuously. For small towers, a soft rammer can also be used to tap and gently pound them to compact them. Large and medium-sized towers can be oscillated using electric oscillators to assist with loading. After filling, the tower must be purged with air or an inert gas to remove the fine powder and dust generated during filling.

What was mentioned above is quite detailed; it refers to the loading plan, and the loading procedures include transportation, weighing, screening, selection, measurement, bagging, lifting, loading, shaking, height measurement, recording, and safety measures

Now, provide personal protective equipment such as coveralls, gloves, and protective goggles with marked scales. There must be a loading plan. The loading procedure includes handling, weighing, screening, sorting, measuring, bagging, lifting, loading, shaking, recording, and safety

When installing the catalyst, care should be taken to ensure that the fragmentation rate is not too high; if it is, it needs to be screened； It is best for each tube to have the same catalyst weight, the same pressure difference, and the same height. Also, be sure to avoid creating a negative pressure in the system after parking the vehicle; otherwise, no amount of protection will suffice. As soon as negative pressure occurs and air gets in, the catalysts in the tower are essentially ruined! The service life of catalysts is influenced by the following factors: 1. Temperature – it’s important to maintain an appropriate temperature. 2. The activity of the catalysts depends on a) physical properties such as surface area, bulk density, and particle size, and b) catalytic chemical properties such as the components of the catalyst, the components of the carrier, and catalyst poisoning

The comrade above explained it very clearly. Still, care needs to be taken during the installation process. Before installing the catalyst, gas displacement must be carried out to prevent poisoning. Of course, the catalyst also needs to be passivated. Zinc oxide hydrogenation catalysts do not require passivation. During installation, sieving is generally necessary; if the particles are too small, it will increase resistance and reduce the space velocity.

Wear a protective mask to avoid heavy metal poisoning!

1. Protect from rain and contamination by debris； 2. Drop protection: Prevent the catalyst from becoming powdered; control the height from which it falls (it is best to use a cloth bag) ； 3. Screening: It is advisable to screen the catalyst before loading it into the tower, in order to prevent powder from entering the tower during transportation. 4. The filling process must be carried out strictly in accordance with the procedures: specifications, quantities, and models must not be incorrect ； The filling area must be even; it should be leveled and measured consistently to prevent concentrated dumping ；

1. Develop a proper loading plan； 2. Prepare the tools for loading, protective equipment, height measurement tools, etc ； 3. Choose a sunny day ； 4. Ensure proper on-site management: the catalyst must be sieved, and it should be filled evenly; it is strictly prohibited for any debris to fall in ； 5. After loading is complete, conduct a thorough inspection before sealing ； 6. The catalyst purge is complete.

I. Purpose of catalyst loading: Catalyst loading is a task of great importance. The quality of this loading directly affects the uniform distribution of airflow within the catalyst bed, as well as helps to reduce the resistance in the bed. It enables the catalyst to function effectively and extends its service life; therefore, it is necessary to minimize damage to the catalyst and prevent the occurrence of \"bridging\" phenomena. II. Preparation work for loading 1) Preparation of tools and equipment: Prepare fine nylon rope, funnels (base funnels), scales, rubber mallets, copper weights, winches, steel wires, record books, measuring tapes, lifting frames, buckets, rubber stoppers (of appropriate size), two sets of long-length respirators, one-piece work clothes, goggles, dust masks or face shields, towels, earplugs, leather gloves, flashlights, two rainproof tarpaulins (10*10m), as well as communication equipment and other tools required for catalyst loading. 1. Confirm that the synthesis tower is clean inside, and that the two discharge ports at the bottom of the tower have been returned to their original positions. 2. The catalyst loading tool has arrived at the site. 3. Inert balls; the catalyst has been delivered to the site. 4. The relevant personnel jointly confirm that the conditions for loading are met. 2) Quantity of high-alumina refractory balls and catalysts: 1. Inert balls – specifications and quantity, main components: SiO2, Al2O3. 2. Catalysts – model, specifications, quantity of methanol synthesis catalysts, filling height inside and on the tubes, volume, etc. 　　 Main components: CuO, ZnO, Al2O3. 2) For personnel preparation, a schematic diagram of catalyst loading should be drawn first; the personnel responsible for loading the catalyst wear integrated work uniforms and carry out the task under the supervision of qualified professionals. Metrologists and measurers must carefully and thoroughly record the catalyst amount and filling height. III. Fill the lower head of the synthesis tower with catalyst material; fill the openings above the wall of the cone cap with high-alumina refractory balls, and then add high-alumina refractory balls weighing approximately 20 tons from the top of the tower. Methanol synthesis catalyst is filled inside the reaction tube and within 200 mm above the upper tube sheet. The upper part of the catalyst is covered with a stainless steel mesh, followed by 100 mm of high-alumina refractory balls. IV. Catalyst Loading Methods and Precautions 1. Loading of refractory balls: Enter the tower from the bottom of the synthesis tower, and check again whether the two discharge ports are in their proper positions as required. First, remove the flange at the outlet of the reaction gas; from there, one can enter the bottom of the tower. Next, open the hole above the cone cap wall. The inert balls are first placed in woven bags and then fed into the tower using a transfer method, so as to fill them evenly at a distance of 100 mm from the tube sheet. Before leaving the tower, confirm the empty area and calculate the approximate cubic volume of the remaining space. Close the upper manhole, then fill the remaining refractory balls from the top of the tower, and seal the manhole at the bottom of the support. People enter the tower through the manhole at the top of the synthesis tower, causing the refractory balls (note: the size of these balls is φ10mm at this stage) to fall from inside the pipes to the bottom of the tower, thereby filling in the empty spaces. Copper weights are used to check whether each pipe has been filled to the lower tube sheet; if not, more balls are added until the pipe is fully filled. Until the copper weight test is passed to confirm that the inert balls are fully installed. 2. Catalyst loading: Lay a 10*10 m canvas on a clean surface, and sieve the new catalyst using a Φ2.5 mm sieve; if there is little dust present, sieving is not necessary. Pour the catalyst into the hopper. The winch (or crane) is started to lift the bucket to the top of the tower; the catalyst inside the bucket is carefully placed into the funnel (base bucket) using control plates. The catalyst then flows down through the funnel (base bucket) into the synthesis tower. Operators wearing coveralls fill the catalyst evenly into the (4,513) tubes inside the tower, following a sequence that starts from the periphery and moves toward the center, continuing this process until the surface of the reactor’s tube sheet is covered. During the loading process, attention should be paid to measuring the height of the space inside the furnace tube, and the height should be adjusted to ensure a uniform distribution of the catalyst. When filling reaches 200 mm above the tube sheet, stop filling and level it off. When loading, one should not step directly on the catalyst; instead, several pieces of sanded wood should be placed on it to prevent it from breaking. 3. Filling with φ10 refractory balls: After filling is complete, a stainless steel mesh panel is placed on top of the catalyst; the mesh is connected using stainless steel wires, and a layer of φ10 refractory balls with a thickness of 100 mm is installed on this mesh. After loading is complete, clean the reactor distributor, the manhole at the top of the tower, and the site. Confirm that loading is complete and the manhole is back in place. A schematic diagram of the synthesis tower is attached below. 4. Precautions: 1) Handle the catalyst gently when moving it in and screening it to avoid damaging it; follow the loading procedure strictly to prevent bridging. During loading, the falling height of the catalyst at the lower end of the cloth bag exceeds 30 mm. 2) Ensure that the fold at the bag opening does not open during the descent of the catalyst. 3) The operators must wear coveralls and shall not carry any items unrelated to catalyst loading. Persons entering the tower must not bring any foreign objects inside to prevent them from falling into the furnace tubes. Wear protective gear to prevent poisoning. 4) When adjusting the height, the striking force of the rubber mallet should be consistent, and instructions from the personnel on top of the furnace must be followed. 5) The staff should wear the necessary protective equipment to prevent damage to the human body caused by catalyst dust. 6) A dedicated person should be in charge of the entire catalyst loading process, from retrieving it from the warehouse until it is fully loaded. 7) The catalyst should be handled with care during transportation; throwing or dropping it violently is strictly prohibited to prevent damage. 8) Keep proper filling records; filling must be done on sunny days. Catalysts must not get wet; on rainy days, outdoor catalyst tanks should be covered with rainproof tarps. 9) It is strictly prohibited to allow any foreign substances to enter the tower during loading; in particular, Cu-based catalysts must not come into contact with iron, as iron acts as an active catalyst for methane synthesis within the synthesis tower. 10) When loading the catalyst into the tube sheet, the loader stands on a sanded wooden board to prevent crushing the catalyst. 11) After the C-306 catalyst has been loaded, thoroughly clean the distributor of the synthesis tower as well as the manhole at the top of the tower. 12) Once the relevant personnel confirm that the loading is satisfactory, the manhole is returned to its original position. 91YT (2009-2-20 23:57:45) 1. Precautions for catalyst loading: The quality of catalyst loading has a direct impact on subsequent normal production, energy savings and consumption reduction, as well as on extending the catalyst’s service life. Therefore, it is required that: A. A dedicated person should be in charge of the entire catalyst loading process, from retrieving the catalyst from the warehouse until it is fully loaded ； During the loading process, B catalyst should be handled with care; it is strictly forbidden to drop or throw it forcefully to prevent damage to the catalyst ； The C catalyst must not get wet at all; on rainy days, the catalyst tanks placed outdoors should be covered with rain shields ； It is strictly prohibited to allow any foreign substances to enter the tower during the loading of D catalyst; in particular, when loading copper catalyst, iron must not be introduced, as iron acts as an active catalyst that promotes the conversion of syngas into methane within the synthesis tower ； The E catalyst should be poured into the synthesis tower slowly, and it must be spread evenly in all directions during pouring to ensure that the gaps between the catalyst particles are uniform. 2. Catalyst deactivation: In a methanol synthesis tower, the copper catalyst used therein has its copper oxide reduced to metallic copper atoms prior to operation. When this metallic copper is removed from the synthesis tower, oxygen in the air comes into full contact with the catalyst; it can rapidly penetrate the inner surface of the catalyst within a short time, generating a large amount of reaction heat. This leads to excessive local temperature rises or sharp increases in temperature differences. As a result of the resulting expansion pressure, certain components inside the synthesis tower may deform or even crack, thereby causing damage to those components. The passivation of a catalyst refers to the slow oxidation of the catalyst by introducing a controlled amount of oxygen into pure nitrogen before removing the catalyst; this process results in the formation of an oxide coating on its surface. This oxide layer prevents further reaction between oxygen and the copper metal atoms, thereby avoiding damage to the components inside the synthesis tower when the copper catalyst is removed, and thus serving to protect those components. During passivation, the oxygen concentration entering the reactor is maintained at 0.4% to 0.8%, while the reaction temperature is kept around 250°C, with a maximum of 300°C. When the oxygen concentration entering the reactor increases gradually to 2% to 3% and the catalyst’s humidity no longer rises significantly, it indicates that the passivation process is complete; the catalyst can then be removed after cooling down.

May I ask whether it is the owner or the construction party who is responsible for loading the catalysts?