What is the purpose of packing trays in a distillation column?

Industrial distillation columns use either trays or packing to promote vapor-liquid contact in separating the components of liquid mixtures to the desired purity.

What is sieve tray distillation column?

Sieve Trays The “Sieve tray” is a perforated plate type tray, with holes punched into the deck-plate that typically measure from 3/16” up through 1” in diameter. Typically, a standard hole size can measure 0.5” OD. Vapor comes out of the holes which in turn, keeps the liquid from weeping through.

What is column packing in distillation?

Packed distillation columns are filled or “packed” with a material that allows rising vapors to contact descending condensate. The more vapor liquid contact the better the separation. Packing material of construction should be compatible with the material being distilled.

What is the difference between packed column and tray column?

Packed towers offer a lower pressure drop. Tray towers are better at handling solids or other sources of fouling. Tray towers are better at handling lower liquid rates. Packed towers are better for corrosive liquids.

Is packing more expensive than trays?

Tray vs. Packing. The difference in cost between plate and packed columns is not too great, although packings are generally more expensive than plates. In addition, the difference in column height is not usually significant if the flow rates are such that efficiencies are near maximum.

What are the types of tray?

• Fast Food Serving Trays. One of the most common types of serving trays that you will see on a regular basis will be fast food serving trays.
• Serving Trays with Compartments.
• Appetizer Serving Trays.
• Tea Serving Trays.
• Plastic Serving Trays.
• Wooden Serving Trays.
• Metal Serving Trays.
• Fiberglass Serving Trays.

What is HTU and NTU?

The number of transfer units (NTU) required is a measure of the difficulty of the separation. The height of a transfer unit (HTU) is a measure of the separation effectiveness of the particular packings for a particular separation process.

What is packing pressure drop?

The horizontal axis is the logarithmic value of the gas velocity G, and the vertical axis is the logarithmic value of pressure drop per height of packing [ pressure drop in a packed bed is the result of fluid friction that is created by the flow of gas and liquid around the individual solid packing materials ].

How are sieve trays used in distillation columns?

The design methodology was obtained as a modification of the procedure proposed by Kister for conventional distillation columns. During designing, the trays were tested to avoid both flooding and weeping. Designed trays were tested using CFD simulations to observe its hydrodynamic performance during operation of the column.

How does the column work in a distillation column?

Being lighter, vapour flows up the column and is forced to pass through the liquid, via the openings on each tray. The area allowed for the passage of vapour on each tray is called the active tray area. A tray essentially acts as a mini-column, each accomplishing a fraction of the separation task.

Which is better packed towers or trays for distillation?

These materials provide the surface area for the distillation process. The Raschig ring was the first packing material but newer shapes provide low pressure drop and high surface area per unit volume. Structured packing towers offer more surface area and have a lower pressure drop than packed towers do.

How are bubble caps used in the distillation column?

A weir on the tray ensures that there is always some liquid (holdup) on the tray and is designed such that the the holdup is at a suitable height, e.g. such that the bubble caps are covered by liquid. Being lighter, vapour flows up the column and is forced to pass through the liquid, via the openings on each tray.