Distillation
Trays

Once the process design stage ends, the equipment design begins. This stage of design converts process requirements into actual hardware.

Selection Guide
for Tray Column

The factors discussed below influence the choice between trays & packings. As these are guidelines for selection of trays or packings for a particular service, it is recommended to analyze each design case on its own merit for selection.

Sr. No.

System Favoring Tray Column

System Favoring Packed Column

01

Solid handling

Vacuum system

02

High liquid rate feed composition and

temperature

Low pressure drop application, Revamps- The pressure drop reduction

03

Large diameter columns Small diameter columns< 900 mm

04

Performance prediction is easy Corrosive system Or Foaming system

Types of
Tray

The particular tray selection and its design can materially affect the performance of a given distillation, absorption, or stripping system. Each tray should be designed so as to give as efficient a contact between the vapors and liquid as possible, within reasonable economic limits.

A] SCM Valve
Tray

Valve trays are perforated sheet metal decks on which round, liftable valves are mounted. The vapors flows through valves which are installed parallel to the outlet weir.

Vapour flows lifts the caps, thus self creating a flow area for the passage of vapour. The lifting cap directs the vapour to flow horizontally into the liquid, thus providing better mixing than is possible in sieve trays.Valve trays combine high capacity and excellent efficiency with a wide operating range.

Fixed Valve Trays Floating Valve Trays
Advantages:

  • Excellent liquid/ vapors contacting.
  • Higher capacity.
  • Higher flexibility than sieve trays.
  • Can handle higher loadings.
  • Low-pressure drop than bubble cap.
Trays Floating Valve Trays
Distillation Equipment

B] SCM Sieve
Tray

Sieve trays are flat perforated plate in which vapour rises through small holes in tray floor, & bubbles through liquid in fairly uniform manner. They have comparable capacity as valve trays.

Vapour passes straight upward through the liquid on the plate. The arrangement, number and size of the holes are design parameters.

Advantages:

  • Simple construction Low entrainment,
  • low cost Low maintenance cost
  • Low fouling tendency

Disadvantages:

  • Less-flexible to varying loads than
SCM Sieve Tray Tower
DistillationEquipment

C) SCM Bubble Cap
Tray

Riser or chimney fitted over each hole, and a cap that covers the riser. The cap is mounted so that there is a space between riser and cap to allow the passage of vapour. Vapour rises through the chimney and is directed downward by the cap, finally discharging through slots in the cap, and finally bubbling through the liquid on the tray.

SCM Bubble Cap Tray
Distillation Equipment