Precautions for installing distillation column packing

(On the second floor, you completely strayed from the topic; you were talking about sealing packing, while the original poster was referring to the packing used in packed towers to enhance gas-liquid contact.) The following are the precautions for installing structured packing: 1. The inner wall of the tower must be smooth; welds need to be polished, and any protrusions or irregularities that could affect the installation of the packing must be removed. 2. The upper surface of the packing support grid must be level. 3. The installation orientation of adjacent pieces of packing should be perpendicular to each other. 4. The installation orientation of the bottom layer of packing should be perpendicular to the support grid, while the installation orientation of the distribution slots in the distributor should be at 90 degrees or 45 degrees to the installation orientation of the top layer of packing. This post was last edited by tanmx on 2009-3-15 at 16:50.]

a. First and foremost, the processing and inspection of the packing are of utmost importance. If the outer diameter of the packing is much smaller than the inner diameter of the tower, wall flow will inevitably occur regardless of how well it is installed, which in turn directly affects the efficiency of the tower. The general requirement for manufacturing fillers is that they should have the same diameter as the inner diameter of the tower at the time of cutting; thereafter, bands are added and the filler is compressed so that its size is slightly smaller than that of the components inside the tower, which facilitates installation. When installing it, a certain amount of force is needed to push it in place. Of course, an overly large packing is also not suitable, as it makes tower installation difficult. b. The filler discs are at 90 degrees to each other and kept level. c. Be sure to make a mark after installing each disc, as this is important to avoid any hollowing out. d. Strict acceptance of the tower is just as important as the installation of the filler.

The distributor and the distribution channels need to be aligned in the same direction; I’m not sure if what I’m saying is correct

My information is based on theory; I have not yet applied it in practice. For specific procedures, please follow the advice of experts! The manufacturing and installation of tower packing are generally carried out by packing manufacturers, who also provide the performance data for the packing as well as guaranteeing its quality, so no further explanation is needed here. (1) Pre-installation treatment of the packing ① Oil removal from the packing: There is a thin layer of oil on the surface of the new packing; this layer of oil may have formed as a result of the use of lubricants during the processing of the metal packing, or it may be rust preventive oil added to prevent carbon steel packing from corroding during transportation and storage. The presence of this layer of oil is absolutely unacceptable in certain systems; for example, in air separation systems, when the oil layer is washed away and comes into contact with liquid oxygen, it can cause an explosion. In aqueous solution systems, this layer of oil can prevent the formation of a liquid film; in some alkaline systems it can also cause the solution to foam. Therefore, it is necessary to understand the physical properties of this oil and remove it before starting up the system. To facilitate the removal of oil layers, it is better to use water-soluble lubricants in filler processing. Carbon steel packing should be stored in a dry and sealed place, and should not be removed in advance to prevent rust. ② Removal of fragments from ceramic fillers: New ceramic fillers as well as those that have been refilled should have any fragments removed from them; sometimes this requires manual removal of each fragment one by one. It is inevitable that bulk ceramic fillers get damaged during transportation, but larger pieces of broken filler can still be used. Their flow rate may decrease and the pressure drop may increase, but the separation efficiency will not decline. ③ Removal of the tower support rings: When converting a plate tower into a packed tower, it is necessary to remove the original tray plates, downcomers, and support rings. The horizontal support ring should be cut as clean as possible. The horizontal support rings are retained; they interfere with the gas-liquid distribution inside the tower, reduce its effective cross-sectional area, thereby increasing resistance and reducing flux, which in turn leads to a decrease in efficiency. Reforming a plate tower with bulk packing requires no demolition as long as the area of the tower’s support ring is less than 10% of the tower’s cross-sectional area. Rectangular packing is used to modify plate towers; before installation, the support rings should be removed and polished clean, with the remaining amount generally should be less than 5 mm, or the advice of the packing manufacturer can also be followed. (2) Installation of packing and internal tower components: Welded components such as packing supports, liquid collectors, and gas-liquid distributors should be installed before the packing is put in place, to prevent welding slag from entering the packing and causing a fire. The oil layer on the surface of metal fillers can easily catch fire under the high temperatures generated by welding slag, while plastic fillers are even more likely to cause fires. The slag remaining in the tower can also cause blockages in the liquid distributor, affecting the efficiency of the tower. If certain components must be installed during or after the packing process, asbestos cloth, asbestos sheets, etc. should be placed beneath the welds to isolate the welds from the packing. Installation steps for packing and internal components: Install the packing support ；  Install packing ；   Install the packing fixing or compressing device, and level it ；  Install the liquid distributor or redistributor, fix it in place and adjust its level ； After installation, check it.  (3) Installation of the packing: The installation of the packing is crucial for ensuring the separation efficiency of the tower, and it must be carried out under the guidance of technicians from the packing manufacturer. Improper installation can lead to poor distribution of gas and liquid, resulting in reduced separation efficiency and processing capacity as well as an increase in pressure drop. ① Installation of bulk packing: The installation of bulk packing seems simple – just pour the packing into the tower. However, this is not the case; such a straightforward installation can, in mild cases, result in uneven packing density, while in more severe cases it can cause the metal packing to deform or the ceramic packing to break. This leads to an uneven distribution of gas and liquid, thereby reducing the separation efficiency. Ceramic fillers and non-carbon steel metal fillers should be filled using the wet method if conditions permit. Wet filling is used: after installing the support plate, water is filled into the tower, and the packing is gently poured into the water from above; the packing floats down in the water, with the water level being at least 1 meter above the packing. Wet filling can reduce filler damage and deformation. Wet filling also improves the uniformity of the bulk filler; the amount of filler used is reduced by about 5%, the filler flux increases, and the pressure drop decreases. Billet conducted comparative experiments using Dg38 Pall rings for wet and dry filling in a 500mm diameter tower; the results showed that wet filling required 5% less filler than dry filling, the pressure drop was reduced by 10%, and the efficiency was almost identical. Therefore, wet filling should be used as much as possible in situations where flux is limited. When using dry packing, the filler should always be poured from a certain height above the packing layer. For towers with large diameters, dry packing is employed, and sometimes it is necessary for a person to stand on the packing layer to carry out the filling. It should be noted that people must not stand directly on the packing to prevent it from being compressed and deformed or having uneven density; wooden planks can be placed on the packing to distribute the stress. Whether wet filling or dry filling is used, the filling should proceed from the tower walls toward the center to prevent bridging of the packing at the wall areas. The packing should not be compressed too tightly to avoid deformation and uneven density. After the packing in each section has been installed, it is necessary to check whether the upper part of the packing is level; if there are any unevenities, they should be leveled out. ② Installation of structured packing A. Dimensions of structured packing Structured packing cannot be installed in a tower arbitrarily, without considering the shape of the tower, as is the case with bulk packing. It must be manufactured and installed based on the dimensions and shape of the tower, as well as the requirements regarding the tower’s ellipticity mentioned in the previous section. When upgrading old towers with structured packing, the ellipticity of such packing often fails to meet the required standards; therefore, it is necessary to address this issue through proper manufacturing and installation of the packing to ensure that it is suitable for the tower structure. For small towers with a diameter of less than 800 mm, the structured packing is usually made in the form of complete disks that are installed via flange holes. For towers with a diameter greater than 800 mm, the structured packing is usually divided into several pieces, which are inserted into the tower through manholes and arranged in a circular shape inside the tower. Whether arranged as a single circle or in separate pieces, their diameter must be smaller than that of the tower; otherwise, they cannot be installed. The gap between the packing and the tower wall should be determined based on the type of anti-wall-flow ring used; each packing manufacturer typically has its own standards. B. Anti-wall-flow rings for structured packing: These are typically used to prevent gas-liquid wall flow that occurs due to the gap between the packing and the tower wall; anti-wall-flow rings are installed in this gap. This baffle flow ring can be integrated with the packing or assembled separately inside the tower. For small-diameter solid disk packings, the anti-wall-flow ring is usually integrated with the packing; sometimes a single ring serves two purposes – it functions as both an anti-wall-flow ring and as part of the packing itself. The anti-washout ring should not completely seal the gap between the packing and the tower wall in the vertical direction; this not only reduces the tower’s throughput and increases resistance, especially in towers with small diameters, but experiments have also shown that it leads to a decrease in separation efficiency. In the figure, several common types of anti-wall-flow coils allow the gas-liquid mixture to flow in a baffled manner through the gaps in the tower wall; this prevents wall flow while simultaneously utilizing those gaps for mass transfer. C. Installation of small-diameter solid-packed packing: When installing small-diameter solid-packed packing, first turn up and align the anti-wall-flow rings; then place the corrugated sheets of adjacent packing discs at 90-degree angles inside the tower, pressing them down with discs as appropriate. For towers with a high packing layer height and a slightly larger diameter, in order to prevent the situation shown in the diagram from occurring, a push plate can be used to guide the packing trays to the desired position; however, this requires personnel with installation experience to carry out the operation. It is also possible to thread several packing trays together before inserting them into the tower, or two people can use steel bars to hook the packing trays and lower them to the intended position. D. Installation of large-diameter structured packing: Large-diameter structured packing must be installed in sections through the manhole into the tower. The height of each section is usually between 100 and 300 mm; the length of each section can be equal to the span of the tower or it can be divided into several sections. To facilitate manufacturing, packaging, transportation, and disassembly, the length of each piece should not exceed 1.8 meters. In each packing piece, the packing sheets are assembled using pins; sometimes, metal wires or packing tape are simply used instead. To prevent the screen filler from deforming during transportation, metal corners are used to protect it. If the anti-wall-flow ring is integrated with the packing, it must be opened as required before each piece of packing is installed; if the anti-wall-flow ring is separate from the packing, it needs to be placed in position as required during installation. Typically, the installation proceeds from one end to the other, with the corrugations of adjacent packing discs forming a 90-degree angle. Every four packing discs constitute one cycle; by rotating the packing discs in a clockwise (or counterclockwise) direction in this manner, the horizontal error on the upper surface of the packing can be reduced. After each tray of screen packing is installed, remove the wrapping corners. Installers should not always stand in the middle of the tower cross-section, as this can lead to a \"bottom of a pot\" effect with higher levels on the sides and lower levels in the middle. The installation of the final piece of packing for each disk requires the use of a sliding plate, as shown in Figure 9. Due to the non-circular shape of the tower and other reasons, it is sometimes necessary to add or remove packing pieces as appropriate in order to make the packing fit the tower structure. Over-tightening the packing can cause the packing sheets to deform, increasing the overall height of the packing and resulting in an uneven upper surface, which in turn reduces the efficiency and flow rate. Similarly, if the packing is installed too loosely, it will lead to uneven gas-liquid distribution and a decrease in separation efficiency. In certain special cases, due to lack of time or other reasons, it is not possible to remove the tray sections in a plate tower and replace them with structured packing; therefore, packing pieces with diameters matching those of the tray sections must be manufactured for installation at those locations. The design must take into account the resulting losses in efficiency and flow rate. (4) Inspection before sealing: Discrepancies between installation and design often lead to problems; the earlier errors are detected, the easier it is to correct them. Therefore, inspections should be carried out simultaneously with installation. Inspections should preferably be carried out by on-site technical service engineers or designers. These professionals generally have a good understanding of the fluid flow and mass transfer conditions within the tower, which makes it easy for them to identify errors. Moreover, on-site inspections serve as an excellent way to improve design skills, leading to more refined designs in the future. It is best to prepare a checklist in advance and check each item against it to avoid omissions. For the modified tower, special attention should be paid to the parts that have been modified. After installation, it is advisable to conduct a cold test using water or another medium if possible, in order to check the distribution by the liquid distributor and the collection by the liquid collector. This task can be carried out simultaneously with cleaning the packing. Once the testing is complete, the impurities present in the liquid distributor and collector should be removed from the tower before it can be sealed. This post was last edited by Chuangxin Filler on 2009-3-20 at 17:51.]

It’s truly professional; I’m working on an engineering project that requires knowledge regarding fillers. Thank you

There are quite a few things to pay attention to; we have just completed the installation of the methanol distillation tower

First and foremost, the levelness of the tower is of primary importance； Next, consider the cleanliness inside the tower; finally, look at the qualification rate of the components within the tower. Of course, inspection is the final step, which must be carried out strictly.