Structured Packing are used in process industry to treat the distillation, absorption operations for getting desired accuracy. Structured packing is one of the type of packing which offers lowest pressure drop in the distillation segment. But those packing are only effective when it has been followed as per the expertise engineering technology.

Structured packing has diversified for their use in specialized applications as well. Various types have been derived according to their application suitability,

Type of Structured PackingOperational ConditionsSpecificationsApplications
Gauge/WiremeshLow Liquid Rate and Deep VacuumOffers lower pressure drop per stagePharma and Specialty Chemicals
KnittedSmall Dia ColumnsMulti strand wires having high surface areaColumn Manways
Sheet MetalHandles a modest fouling and adequate liquid loadAble to handle wide range of process fluid ratesLow pressure drop column to medium high pressure absorber
GridMostly for fouling casesCorrugated sheets has smooth surface which minimises foulingCompatible with high fouling rate

Advantages of Structured Packing-

Structured packing provides effective mass and heat transfer because of the flow of liquid in the column in counter current manner. Selectivity of packing in the column can be also categorised as,

a) Small diameter towers –In case of tower diameter below 0.9 m (3 feet), it’s difficult to install trays so the packing will be better choice to maintain tower. Packing are cheaper and desirable compared to trays.

b) Low pressure drop –Pressure drop is always lower in the packing comparative to trays. The open area of packing usually greater than 50 % while tray has only about 5-10%.

c) Corrosive system – wide range is available for packing like metallic, ceramic etc. It can be used in corrosive applications.

d) Revamping Towers – In most cases, existing towers are revamped for higher capacity by replacing trays by packing.

Selection of Structured Packing over Trays-

Selection of Structured packing over trays is also a factor of operational suitability.

  1. Packing can offer low pressure drop than trays.
  2. They provide more inter-facial area for better mass transfer efficiency.
  3. Height of the column can be shortened in case of packing compared to trays.
  4. They can handle corrosive fluids in better way than trays.
  5. It offers better separation efficiency.
  6. Better constant contact can be made in the operation.

Structured Packing over Random Packing-

Structured Packing can also be selected as per their performance in the operation. They are offering better workability over random packing like, it provides higher efficiency even with higher capacity and offers lower pressure drop. Liquid holdup is also reduced in the structured packing but they are costly than the random packing.

Advantages of Structured Packing-

Structured packing promotes filmed liquid distribution and which improves the overall performance. Textured designing of plates promotes liquid spreading. This packing is compatible with low pressure drop and high flow volume. Lower pressure drop means higher volatility which will be an advantages in operation. It reduces foaming even at higher operating rates.

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