Liquid Distributor

Drip Tube Deck Distributor

To achieve maximum efficiency in a packed column, liquid must be distributed uniformly across the entire packed bed. For this reason, liquid distributors are installed above each packing bed.

Well-designed distributors typically meet the following specifications:

· Uniform liquid distribution

· Wide operating flexibility and turndown ratio

· Low vapor pressure drop

· Short liquid residence time

· Compatibility with liquid collectors for redistribution

· Minimum overall height

· Anti-fouling performance

· Good cross-mixing capability

In mass transfer processes, uniform distribution of liquid and gas is critical. If liquid and gas are not evenly distributed over the tower cross-section before entering the packing bed, the actual liquid-to-gas ratio will deviate from the design value, resulting in reduced separation efficiency or even process failure.

To ensure intimate phase contact and high mass transfer efficiency, gas and liquid must be uniformly distributed at any cross-section inside the packed column. Therefore, the liquid distributor — especially the pre-distributor — is of primary importance.

The liquid distributor is a key internal component in packed columns, mounted above the packing hold-down plate and connected to the liquid inlet. Its structure must be reasonably designed to avoid interference with the hold-down device, thereby ensuring high mass transfer efficiency.

What types of liquid distributors are available?

Liquid distributors are classified into various types based on design standards and operating conditions. Generally, there are four main categories:

1. Spray Nozzle Distributors

Hemispherical spray nozzles achieve uniform liquid distribution over random or structured packing. The nozzle is equipped with numerous small holes, typically 3–10 mm in diameter.This type is suitable for small-diameter packed columns (≤ 600 mm).

2. Perforated Pipe Distributors

Single or double rows of perforated pipes distribute liquid evenly through holes on the underside of the pipes.They are widely used in medium liquid load services, vacuum distillation columns, and wire gauze structured packing columns. They can be manufactured in ladder or ring configurations.

3. Through-Type Distributors

This category includes through-type and through-pan distributors.They are widely applied under high liquid and gas loads, for high-viscosity liquids, and for liquids containing suspended solids.

4. Orifice-Type Distributors

These can be divided into perforated plate types and pan types. Liquid flows downward through orifices or overflows from the annular space between the distributor and the tower wall.This type is suitable for small-diameter columns (≤ 800 mm).