Catalyst loading plan for methanol plant?

(1) Place two tarpaulins on a clean surface, and use a sieve with an aperture of 3×4 to sift the catalyst out of its container, thereby removing any catalyst ash and debris present. It is best to sieve the catalyst through an inclined sieve, taking care not to crush it during the sieving process. (2) The sieved catalyst is packed into small bags of 10–15 L capacity and lifted to the manway platform at the top of the synthesis tower using a crane. Be careful not to transport the catalyst using iron tools such as shovels. (3) Draw the catalyst filling height line in the synthesis tower according to the expected filling height. (4) The number of people allowed to enter the synthesis tower to load the catalyst is determined based on the diameter of the tower. Those who enter to load the catalyst must wear filtering dust masks and dust goggles, and are not permitted to bring in any items that could fall off inside the tower. (5) When the operator enters the upper tube sheet to load the catalyst, someone must be present near the manhole to supervise and maintain communication. (6) The operator inside the reactor should slowly and evenly load the catalyst into the tubes in accordance with their arrangement order. It is essential to control the loading speed to prevent catalyst bridging. During the loading process, the catalyst on the tube sheet should be frequently swept into the reaction tubes, and each catalyst tube should be installed at a distance of about 5–10 mm from the upper tube opening. Prevent operators from crushing the catalyst. (7) Continue to install another layer of catalyst on the upper tube sheet with a height of about 350 mm (if the design requirements call for more catalyst, the maximum height shall not exceed 550 mm) in order to compensate for the volume contraction of the catalyst after reduction. (8) After loading is complete, lay two layers of stainless steel wire mesh with the same diameter as that of the synthesis tower on top of the catalyst, and press the edges of the mesh with large porcelain balls. (9) After loading is complete and it has been verified that no items remain inside the tower, the lighting fixtures inside the tower can be removed, and the maintenance personnel should be informed to seal the upper manhole. (10) After purging the catalyst dust in the bed with instrument air or nitrogen, the system is then flushed with nitrogen; once the flushing is complete, nitrogen is used for protection while waiting for the temperature to rise for reduction.

Catalyst filling: 1.1 Start from the gas outlet of the synthesis tower and fill the space at the bottom of the lower head with alumina balls of diameter 20–25 mm, ensuring they are level with the manhole opening of the conical support structure. Then, inside the upper head of the synthesis tower, fill the space one by one with alumina balls of diameter 8–10 mm, striving to distribute them evenly and compactly to prevent bridging within the tubes. It is advisable to fill in small amounts and check frequently to avoid overfilling; use a plumb line to ensure that the depth at each point up to the lower tube sheet is 6000 mm. . 1.2 After the alumina balls are filled to the required level, the sieved catalyst is inserted into the tube; it is filled evenly in various sections until the space is completely occupied. A wooden hammer is used for vibration to prevent the formation of \"bridges\". 1.3 After the tube is filled with catalyst, fill it further above the tube sheet to a height of 350 mm; finally, level the surface using wooden planks. To prevent the catalyst from being crushed, the personnel carrying out the filling should stand on the wooden planks and not step on the catalyst. 1.4 After the catalyst surface was smoothed, a stainless steel cover with a mesh size of 3 mm was placed over the catalyst, and a layer of inert alumina balls with a diameter of 8–10 mm was then laid on top of the mesh. 1.5 After the catalyst has been loaded, seal the manhole immediately to prevent moisture absorption and contamination by toxic gases, and then blow out the catalyst powder.

Precautions for loading 2.1 It is strictly prohibited to roll or drop the catalyst barrels during handling. 2.2 Assign a dedicated person to open the barrels and verify the catalyst model and quantity. 2.3 Before loading the catalyst, it must be gently sieved through a Φ3mm sieve to remove any small amounts of powder and debris that may have formed during transportation. 2.4 Before starting the loading process, first open the discharge port to remove various impurities from the synthesis tower, check for any blockages or leftover tools inside the tower, and ensure that all the used catalysts have been removed from the pipes. 2.5 The metering personnel must accurately record the amount of alumina balls and catalyst loaded, and promptly contact the loading personnel. 2.6 Before entering the tower, the personnel responsible for loading must remove their watches, keys, and any other items from their pockets to prevent them from falling into the synthesis tower. Once inside the tower, it is strictly prohibited to walk or step directly on the catalyst; instead, wooden planks should be placed on top of the catalyst, and the surface of the catalyst should be leveled using hands or those planks. 2.7 The climate is variable; loading operations should be stopped when it rains. The top of the tower was covered with waterproof cloth; the uninstalled catalyst was placed in a bucket and sealed, after which the bucket containing the catalyst was stored in a dry indoor area.

I. Preparation Work 1. The technical personnel from the catalyst manufacturer must arrive at the site one day before loading, discuss and approve all plans before proceeding with the work. 2. Organize the assignment of personnel before loading, to ensure unified planning and arrangement. 3. The internals of the synthesis tower must be thoroughly ventilated and cooled before loading. 4. The circulator must be in standby mode before loading, and the cold exhaust system must be functioning properly. 5. Prepare a special sieve, funnel, weighing scale, notebook, pen, and safety rope. 6. Prepare 1 steel bar with a diameter of Φ14mm and a length of 18m, and mark the scales on it ； 50 pairs of masks, 60 meters of red cloth, 2.5 Kg of flour. II. Filling steps: 1. The copper-based catalyst containing methanol has low strength and tends to produce powder; therefore, it should be sifted to remove any powder or debris during filling. Records of the weight and degree of filling should be kept, and it is best to complete this process in one go on a sunny day. 2. Check the installation position of the internals inside the synthesis tower, and align the thermocouple sleeve with the center of the shaft hole in the cover, so as to enable proper alignment of the small cover. Use a basket frame to fix the central tube and the thermocouple sleeve, thereby achieving preliminary alignment. 3. Use red cloth to seal the central sleeve, outer corners, and gaps around the inner components tightly. 4. Since this tower is of the dump-type design, refractory balls are first placed at the bottom of the catalyst basket until it is level; only after confirming that the refractory balls are level can the catalyst be loaded. 5. During the loading process, after loading a certain amount and when changing the particle size of the catalyst, it is necessary to check whether the heights on all sides are consistent. 6. The catalyst loading amount should be determined based on the desired catalyst filling height; it should not be too low, as this will affect the amount of catalyst that can be loaded. The filling height must not exceed the specified limit to ensure proper welding of the filter mesh and the small cover. 7. When the cumulative loading amount in the Φ1400 synthesis tower reaches 1000 Kg, use measuring sleeves to check whether the heights on all four sides are consistent, and keep records of the results. Measure again whether the filling is uniform when it reaches 3000 kilograms; thereafter, it is necessary to measure the uniformity of filling every time another 3000 Kg is added. 8. After the catalyst is installed, clean the catalyst from the annular gap, central tube, and thermocouple sheath. Remove the red cloth and put the cover back in place to prevent the catalyst from falling into the annular gap and thermocouple sheath. 9. The distribution of heavy-duty particle sizes for loading is provided separately. III. Precautions: 1. The catalyst has poor strength; avoid dropping, rolling, and collisions during transportation. 2. The catalyst should be screened before loading to remove powder and fragments. 3. To prevent the catalyst from absorbing moisture and losing its activity, loading should be carried out during the day, preferably on a sunny day. 4. After being stored in air for a period of time, the catalyst’s activity decreases due to moisture absorption and crystal structure changes; therefore, it should be sealed immediately after loading and subjected to heating and reduction. Otherwise, the synthesis tower must be properly sealed. 5. Care should be taken during loading to prevent catalyst particles from falling into the gaps around the tower, as well as into the thermometer sleeves and the central tube. 6. The loading personnel must wear tight-fitting clothing and remove all personal items; all tools of the maintenance personnel must be secured with ropes to prevent them from falling. 7. During the filling process, it is necessary to measure accurately so that the catalyst can be distributed evenly; it should be poured in a quadrilateral shape. When using rebar to measure the height, do not apply too much force, and gently level the catalyst while tamping it to prevent it from breaking or oxidizing. 8. To prevent convection after filling, once everything has been installed, use purified gas (with composition requirements: O2 ≤0.2%, carbon dioxide ≤10PPm, CO ≤10PPm, NH3 ≤200 PPm, total S ≤0.1PPm) to blow away the catalyst powder. This process must be carried out in a forward flow direction, and it is considered complete only when the surface is clean when wiped with a red cloth. 9. After the large cover of the synthesis tower is sealed, contact the instrumentation team to immediately install the thermocouples, put them into use with the computer system, and also connect two temporary moving-coil meters for simultaneous use. A dedicated person should monitor the temperature of the catalyst layer and keep accurate records. Upon detecting an increase in temperature, the circulation pump is activated immediately to keep the catalyst temperature within the normal range. IV. Loading time: 8 hours V. Role allocation Chief commander: On-site supervisor: Person in charge of implementation: Loading personnel: First-level inspection: Second-level inspection: Third-level inspection: