INTRODUCTION Like their pipeline counterparts, Borosilicate glass column components find universal application throughout the world’s chemical, pharmaceutical, food and drink and allied industries where the advantage of using glass as a basis for the construction of complete process systems have long been recognized:
With almost universal resistance to corrosion, a long service life is guaranteed and maintenance is kept to a minimum.
Their transparency permits visual monitoring of the process at all times.
Being inert, the risk of contamination is negligible.
Smooth surfaces allow easy cleaning and sterilization and prevent the build-up of solid on the inner walls.
In many unit operations such as reaction, extraction and absorption, the transparency factor of glass column components is a particular advantage. As an example, colour changes in reaction processes are easily monitored, droplet separation in extraction processes can be observed unhindered and constant visual monitoring of hydraulic performance in packed columns is possible.Column components are available from DN 80 to DN 450 with a smaller range of precision bore components available from DN 25 to DN 150 for specific applications where close internal tolerances are essential.The complete range of column components is described on the following pages. All column components have standard flat buttress end connections. Further details of theses are provided in section: Technical Information.For standard flat buttress end connections from DN25 to DN300, it is possible to achieve a 3° deflection in the joint by using a flexible gasket. Details of these and all other couplings and gasket can be found in section Couplings. DN refers to the nominal bore. Unless otherwise stated all dimensions are given in mm.For permissible operating conditions, unless otherwise stated in the individual description, please see section Technical Information.
Applications of internals
Columns used for reaction, absorption and extraction processes can be fitted with many different internals such as packed beds, structured packing and sieve or bubble-cap trays. The typical operating characteristics, as well as the recommended and possible areas of application for each of these internals, are detailed in this section: the processes beuing limited to gas/liquid operation in the form of rectification and absorption processes.Packed beds or structure packing are used to create the surface required for mass transfer by increasing the area of contact at the surface of the liquid when it flows over the internals as a film. Irregular packed beds have a relatively high pressure drop. Figure 1 shows the pressure drop for ceramic saddles . a very significant reduction in pressure drop, particularly in regard to vacuum rectification, can be achieved by the introduction of structured packing. Figure 2, for example shows the pressure drop values for SULZERKERAPAK. A clear reduction in pressure drop is discernible here.
Applications of internalsIn plate columns the boundary surface for mass transfer is created by the liquid phase flowing across the trays being penetrated by the gas or vapour rising from the plate below. The main distinctions here are between bubble cap trays and sieve trays. Plate columns have higher pressure drop then packed columns. To illustrate this, Figure 3 on the previous page shows the pressure drop of the buyer low-rise tray. The pressure drop of the tray is about the same as for 1 meter packing of 25mm ceramic saddles.The suitability of internals to a particular process is really determined by the process conditions in each case. If a low pressure drop is required, then structured packing are the main ones to choose. In all other cases the permissible operating range of the various internals for a particular application is the determining factor. Packed and plate columns have different operating ranges as a result of the different type of boundary surface creation. The terms operating range here refers to the range of gas and liquid flows within which problem-free operating of the column is possible. Figure 4 shows typical load characteristics of a packed column with the operating range shaded. This is mainly limited by the so-called upper load limit, designated by flooding, against higher flow. The lower load limit designated by minimum wetting stems from the requirements that the packing has to have an even film of liquid to achieve the desired separation. It can also be seen from Figure 4 that it is possible to individual cases, however, the achievable separation effect should be checked.Plate columns have different operating characteristics. As the load characteristics in Figure 5 show, several factors limiting the operating range have to be taken into consideration with this design. It must be emphasized in particular that turndown of the liquid load is much greater for the plate column.
Maximumweight ofpacking(kg) (lbs)
The figures in liters are the volumes available for packing above the supports or, Where applicable, above the two rows of stacked rings. Columns are fundamental to many process plants and a range of column components in borosilicate glass is available in nominal bores up to 1000mm.
Column sections are supplied complete with the appropriate size of packing support. In type C columns, two rows of stacked glass Ranching rings immediately above the support provide a firm base on which the dumped packing is supported. Type C column sections can be supplied with a side branch (for example for thermometer pocket) on special order. This is located near the top of the column section.
Type A supports are glassType B supports are glass and PTFE
Glass packing supports are supplied as part of the column section assembly. They are normally only ordered separately when required as replacements. They are seated on a PTFE crescent ring which is supplied with the support. Two rows of stacked glass rings are also supplied with type B supports.
These plates are fitted at the top of columns as restrainers for column packing where there is a risk of damage to other parts of the installation. They are clamped between buttress ends and a gasket is required on each side. Longer bolts than usual are required in the flanges used with the glass plates.
Support Ring, TFE-Covered
This support ring is made of steel covered with a TFE machined envelope over a compressed fiber gasket. Clamp the support ring between two column sections. For 225 mm size and over, we recommend using a TFE Crescent Ring Gasket (Cat. Ref. TR) on each side of the plate. This makes it easier to get a tight seal, and you can reuse the support ring when you wish. The ring supports either the ceramic packing support plate or the ceramic distributor plate. This ring lets you remove an entire packed section without having to remove the packing first. For bromine service please check with GARG.
Packing Support Plate, Ceramic
Plates are made from white unglazed chemical porcelain in the riser-type "gas injection" design. All ceramic plates have greater than 50% free area. All sizes of these plates can easily accommodate a 3-meter (10 ft) height of any conventional packing material. Consult GARG Process Systems about heights greater than this. To install these plates, center one on top of a TFE-covered support ring; then raise the plate and ring together to meet the column section above. The ceramic plate stays on the edge completely inside the column. Caution: do not try to slide the ceramic plate down from the top of the column section--it may get stuck.
Distributor Plate, Ceramic
This plate is made in one piece from white unglazed chemical porcelain. The gas risers in the center of the plate effectively reduce the pressure drop across the plate and so retard velocity so as to lower the hydraulic gradient effect on the liquid, thereby giving more uniform liquid distribution. For smaller-size distributor plates, simply use a glass packing support plate (in this catalog). For distributor plates capable of handling either lower or higher flow rate ranges, check with GARG Process Systems for plates available on special order.
8 x 8
10 x 10
15 x 15
20 x 20
25 x 25
40 x 40
50 x 50
One standard type of glass column packing is available: Raschig rings. It is especially suitable for use in glass columns because of its low bulk density.
Selection and use of column packing 1. The ratio of column diameter to packing diameter should not be less than 8:1. 2. Where smaller sizes of packing are used, it is sometimes advisable to use a small layer of larger packing immediately above the support to prevent the smaller packing falling through. 3. In vacuum operations and applications involving high vapor velocities glass packing--because of its low weight--may tend to be lifted away from the top of the column sections and may cause damage to other parts of the installation. This can be prevented by fitting a suitable form of restraint (for example a perforated plate) above the column section. 4. Various methods can be used for the random distribution of packing in a column. One method is to fill the column section with water, then dump in the packing. If this is used, care must be taken not to exceed the maximum pressure permissible in the column. 5. Column packings other than the standard glass ones can be used but bulk density should be taken into consideration and the maximum permissible load on the support should not be exceeded.
Precision Bore Pipe Sections
L1 is the approximate length of the precision bore zone of the pipe. The bore of the remaining pipe is not less than the minimum bore of the precision zone. Where the inside diameter of a column must be within closely controlled limits (for example to accommodate sieve plate assemblies), precision bore pipe sections are used.
A + B + C
DN is the nominal bore of the column in which the redistributor is used Type A and Type B redistributors are clamped between buttress ends and no gasket is required. Type C redistributors fit between the packing support and the glass shelf built into the column section.
This device prevents vapors from passing directly into the after cooler and receiver. Install it on the product exit line from the reflux splitter, which also has a 10° pitch. A valve branch DN1 permits sampling and draining. Glass Valves are covered in another section of this catalog.
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