The installation of tower packing
Packing development, manufacturing is generally completed by the packing manufacturer, packing performance data is also provided by the manufacturing plant, its quality should also be guaranteed by the manufacturing plant, here without further ado.
1.Processing before packing installation
(1) filler oil removal
There is a thin oil layer on the surface of the new filler, which may be formed by the lubrication oil used in the processing of
Metal Filler; it may also be to avoid corrosion of carbon steel filler in the process of transportation and storage and the addition of anti-rust oil. The presence of this layer of oil is absolutely unacceptable for some systems, for example in air separation systems, where the oil layer washes off and coexists with liquid oxygen and can cause an explosion. For aqueous systems, the oil can prevent the formation of a liquid film, and for some alkaline systems it can also cause foaming of the solution. To facilitate the removal of the oil layer, a water-soluble lubricant is preferable for the filler process. Carbon steel filler should be stored in a dry and closed place, should not be removed in advance to prevent rusting.
(2) Ceramic filler debris removal
New ceramic packing and refilling of ceramic packing should be sieved out of which the debris, sometimes need to be removed by hand one by one, bulk ceramic packing in the transportation process inevitably broken, large pieces of broken packing can still be used, its flux has decreased, the pressure drop has increased, but the separation efficiency will not decline.
(3) tower support ring removal
Plate tower to fill tower, the original tower plate, liquid drop tube and support ring removal. Horizontal bearing circle should be cut as clean as possible. Horizontal bearing circle retained, in the tower will interfere with the gas-liquid distribution, but also reduce the effective cross-section of the tower, thus increasing the resistance, reducing the flux, the efficiency will also be reduced.
The use of bulk packing transformation plate tower, as long as the tower support circle area is less than 10% of the tower cross-sectional area, do not need to remove.
The use of gauge packing transformation plate tower, in the installation should be removed before the support circle, and polished clean, the residual amount should generally be less than 5mm, can also listen to the packing manufacturer's advice.
2, packing and tower installation of internal parts
Need to weld the inner parts, such as filler support, liquid collector, gas-liquid distributor, etc. It is best to complete before the installation of filler, to prevent welding slag into the filler caused by fire. The oil layer on the surface of the metal filler can easily catch fire under the high temperature conditions of the welding slag, and the plastic filler is more likely to cause a fire. Weld slag left in the tower will also cause the liquid distributor to clog, affecting the efficiency of the tower. If some parts must be installed in the packing process or after the completion of the process, need to be laid under the welding asbestos cloth, asbestos sheet, etc., so that the welding and packing isolation.
Filler and internal parts of the installation steps.
(1) Installation of filler support.
(2) Installation of the filler.
(3) Installation of packing fixing or pressing device and leveling.
(4) Install the liquid distributor or redistributor, fix and level it.
(5) After installation, check.
3, the installation of packing
Packing installation to ensure the separation efficiency of the tower is essential, to be completed under the guidance of the packing manufacturer's technical staff. Poor installation will cause poor gas-liquid distribution, resulting in a decrease in separation efficiency and processing capacity, pressure drop rise.
(1) bulk packing installation
Bulk packing installation looks very simple, the packing will be poured into the tower can, in fact, it is not, so simple installation of the light will cause uneven filling density, the heavy can cause metal packing deformation, ceramic packing broken, thus causing uneven distribution of gas and liquid, so that the separation efficiency decline.
Ceramic filler and non-carbon steel metal filler, if the conditions allow, should be used to fill the wet method. The use of wet filling, the installation of support swing plate, to the tower filled with water, the filler from the water surface above the gently poured into the water, the filler from the water floating down, the water surface should be higher than the filler lm above. Wet filling can reduce the packing breakage, deformation. The wet filling also increases the uniformity of the bulk filler, the amount of filler is reduced by about 5%, the filler flux increases and the pressure drop decreases. billet in 500mm diameter tower with Dg38 bauer ring using wet filling and dry filling for comparison experiments, the results show that the use of wet filling than dry filling with 5% less filler, pressure drop decreased by 10%, the efficiency is almost equal. Therefore, wet filling should be used as far as possible in situations where the flux is limited.
Using the dry method of filling filler should always be from the filler layer from a certain height to pour into, for large diameter tower using the dry method of filling, sometimes need to stand on the filler layer filling. Should need to pay attention to people can not stand directly on the filler, to prevent the filler pressure deformation and uneven density, can be laid on the filler board so that the force is dispersed.
Whether using wet filling or using dry filling, should be filled by the tower wall to the centre, to prevent the filler in the tower wall at the bridge, the filler should not be pressed into place to prevent deformation density is not uniform. Each section of the filler installation should be completed to check whether the upper end of the filler is pushed flat, if there are high and low unevenness, should be pushed flat.
(2) Installation of regular packing
A. Outline size of regular packing
Regulation packing is not like bulk packing as can not consider the shape of the tower, randomly loaded into the tower, according to the size of the tower, shape and the previous section mentioned the regulation packing tower on the tower ellipticity requirements for manufacturing, installation. The use of gauge packing transformation of the old tower, sometimes its ellipticity is far from this requirement, which needs to be from the packing production and installation to solve, so that the packing suitable for the tower body.
For the diameter of less than 800mm of the small tower, gauge packing is usually made into a whole disc by the flange hole installed. For the diameter of the tower greater than 800mm, the whole packing is usually divided into a number of blocks, by the manhole into the tower, in the tower group round, whether the whole round or block group round, its diameter should be less than the diameter of the tower, otherwise can not be installed. Packing and the gap between the tower wall, should be based on the use of anti-wall flow circle form, the packing manufacturers usually have their own standards.
B, the regular packing anti-wall flow ring
Usually to prevent the gap between the packing and the tower wall to produce gas-liquid wall flow, in this gap plus anti-wall flow ring. This anti-wall flow ring can be made into one with the packing, can also be separated to the tower assembly. Usually for small diameter whole disc packing its anti-wall flow ring is made of one with the packing, sometimes a circle of two uses, both to do anti-wall flow ring, but also to support the role of packing. Anti-wall flow ring should not be packing and tower wall gap between the height direction all sealed, which will not only reduce the tower flux, increased resistance, especially the small diameter of the tower, and by experimental evidence will also cause a decline in separation efficiency. Common anti-wall flow circle gas and liquid to fold the flow form through the tower wall gap, both to prevent the wall flow, but also the use of the gap to play a role in mass transfer.
C, the small diameter of the whole disk regulation packing installation
Installation of small diameter whole disk regulation packing, the first anti-wall flow circle flip edge, square, will be adjacent to two disc packing corrugated sheet into 90 degrees angle in turn into the tower, and disc appropriate pressure.
For the filler layer height is higher, slightly larger diameter tower, in order to prevent the situation as shown, can be used to push the disk tracking filler disk, the filler disk to the predetermined location, but must have installation experience personnel to operate, can also be a few disk filler into the tower before wearing a string, together into the tower, or two people using steel bar hook filler, down to the predetermined location.
D, the installation of large diameter packing
Large diameter gauge filler needs to be divided into blocks from the manhole into the tower installation, plate height is usually 100 ~ 300mm, the length of each block can be equal to the length of the tower chord, can also be divided into a number of blocks. In order to facilitate the production, packaging, transportation, disassembly, the length of each piece should not exceed 1.8 m. Each piece of packing in the packing sheet using nail assembly, sometimes also simply using wire or packing tape tied. To prevent the screen packing from deformation in transport, metal wrapped corners are used to protect the packing.
If the anti-wall flow ring is integrated with the packing, the anti-wall flow ring needs to be opened before each piece of packing is installed as required; if the anti-wall flow ring is separated from the packing, the anti-wall flow ring needs to be put in place as required during installation. Usually the installation starts at one end and ends at the other end, with the corrugation of the two adjacent packing plates at an angle of 90 degrees. Every four plates of packing for a cycle, so into a clockwise (or counterclockwise) direction to turn the assembly of packing plate, can reduce the packing on the end of the level of error. Wire mesh packing each plate after the installation and then remove the corner of the package. Installers should not always stand in the middle of the tower section, so easy to form around the high middle of the low "pot bottom" phenomenon.
Each plate packing assembly last piece need to be installed with the help of slide plate. Due to the tower is not round and other reasons sometimes need to fill the discretion to add or reduce the piece, in order to make the filler suitable for the tower body. The packing installation is too tight will lead to deformation of the packing sheet, the total height of the packing "higher", the upper end surface is not flat, the efficiency flux decreased. Similarly, too loose packing installation will lead to uneven gas-liquid distribution and reduced separation efficiency.
Some special circumstances, due to time does not allow or other reasons, plate tower to rectify the packing tower tower ring can not be cut, need to make some diameter and tower circle in line with the packing, in order to install at the tower circle, the design should consider the resulting efficiency and flux loss.
4, seal before the inspection
Installation and design inconsistencies are often to produce trouble, the earlier the error is found the easier to correct, so the inspection should be carried out at the same time as the installation. Check the best by the site technical services engineering and technical personnel or design personnel, site services engineering and technical personnel and design personnel generally have a better understanding of the tower fluid flow conditions and mass transfer conditions, it is easy to find errors; In addition, the site check is also a good exercise, can improve the design skills, so that the future design more perfect.
The best check is to list a checklist in advance, check against the table item by item to prevent omissions. For the renovation of the tower, should focus on checking the renovation of the part.
Installation is completed, such as the best conditions to use water or other media cold test, check the distribution of the liquid distributor and liquid collector collection, this work can be carried out at the same time with the cleaning filler. Test is completed, will exist in the liquid distributor, collector impurities out of the tower, can seal the tower.
