Liquid-Vapor Separation: Structured Packing in Distillation Columns

We need vapor-liquid separation in many industries such as gas refineries and oil pipelines. We also use it in air conditioning, paper mills, and soil vapor extraction. In a separate application, we also see the need for liquid-liquid separation. The most popular application of this is the petrochemical industry. Here we need to separate the diesel from the gasoline and kerosene before we can use them.

Distillation column and its internals

The most popular method used for this is the distillation column. They can vary in size from the laboratory model measuring a few meters to the gigantic industrial models that may be as much as 80 meters tall. Here you will see the use of structured packaging, distributor, pall rings, and trays within the column to help separate the gas from the liquid. You can get the exact details from the Structured Packing Manufacturers.

You can use a vapor-liquid separator which is nothing but a flash drum or a knockout drum. We refer to it as a demister when we use it to remove the water from the liquid or gas. In usual cases, we use gravity to separate the liquid from the other components. But, when this is not possible, they use a centrifuge machine. This rotates the components at high speed to create the force needed to separate the material having different densities.

Parts in the structured packing

The structured packaging is the most important item of the column internals used in a distillation column. They have special material that helps in the absorption and distillation processes. Distillation applications include steam stripping, solvent drying, product purification, and solvent recovery systems. It forces the fluids to take circuitous paths thereby increasing the contact surface area. This allows for better separation of the gas and liquid or liquid and liquid.

They use perforated sheets made of plastic and metal to make the structured packaging for the distillation columns. The Column Internals Manufacturers have many models and you can pick the one that you want to use for your application. If you use only random packaging or trays, you will experience a bigger pressure drop. The efficiency for the unit height of the tower decreases and the capacity improves. Also, the liquid hold-up is lesser.

Use of liquid distributors

The liquid distributors and redistributors are inside the distillation columns. They are above each bed of packing. The redistribution is between each packed bed. It gives a uniform point-to-point flow and the drip-point pattern is uniform. When used for distillation services it gives a high stage count per bed. The operation is near the least reflex ratio bringing it close to an equilibrium pinch.

The reason for making a single pack bed into two beds is to get a product side draw and feed introduction. The unit count of transfer remains high, and we can prevent the liquid maldistribution. The physical weight of the packed bed now becomes lesser. You have many kinds of liquid distributors. The popular ones are the spray nozzle distributor, midget load spray distributor, and the high liquid load distributor. Other popular models are the bottom hole distributor and the lateral distributor.

Finepac Structures Pvt. Ltd. is a leading manufacturer, suppliers, & exporters of a wide array Structured Packaging, Column Tray and more.