Column Sections

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.

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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 internals

In 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.

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Column Sections

DN (mm)	L (mm)	Volume (L)	Volume Stacked Rings (L)	Free Area	Minimum Packing Diameter (mm)	Maximum weight of packing (kg) (lbs)
80	1000	4		50%	7	20	45
100	1000	8		60%	10	30	65
150	1000	16		65%	15	60	130
225	1000	32		75%	20	90	200
225	1500	51		75%	20	90	200
300	1000	60		75%	25	150	330
300	1500	95		75%	25	150	330
450	1500	186	14	75%	25	250	550

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 

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. 

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Packing Supports

DN (mm)	L (mm)	Free Area	Maximum Load (kg) (lb)		Minimum Packing Diameter (mm)	Type	Cat Ref
80	15	50%	20	45	7	A	GLB3
100	20	60%	30	65	10	A	GLB4
150	30	65%	60	130	15	A