Distillation is a process in which a liquid or
vapour mixture of two or more substances is separated into its component
fractions of desired purity, by the application and removal of heat.
Although many people have a fair idea what "distillation"
means, the important aspects that seem to be missed from the industrial
point of view are that:
- Distillation is the most common separation technique.
- It consumes enormous amounts of energy, both in terms of cooling
and heating requirements.
- It can contribute to more than 50% of plant operating costs.
The best way to reduce operating costs of existing units, is to
improve their efficiency and operation via process optimisation and
control. To achieve this improvement, a thorough understanding of
distillation principles and how distillation systems are designed is
essential.
Uses
Distillation systems are used for steam and wastewater stripping,
chemical product purification, and solvent recovery. Distillation system
consists of metal cylinders armed internally with perforated horizontal
plates that are used to promote the separation of miscible liquids that
ascend as vapor.
Distillation systems are also used to perform steam stripping or
distillation of wastewater for removal of hydrocarbons such as alcohols,
ketones, and acetates. A distillation system can mix waste products so
they are discharged as a sludge, paste, or powder depending on the
specific industry's best disposal practices. Distillation systems are
used to recycle and recover contaminants from the manufacturing of
polymers, resins, and paints.
Distillation systems may contain several other functional components,
including an adsorption column or bed, where molecules of solvent in
liquid or gas form adheres to the surface of a solid material, rather
than enter the solid as in absorption. An aeration column is used when
treating wastewater and involves pumping the water through a series of
columns to add oxygen to the wastewater. Aeration increases the surface
area of the contaminated water allowing a waste solvent recovery system
to remove any volatile compounds more easily. A telescoping column may
also be available from some suppliers of distillation systems.
Applications of distillation system industrywise
- Hydrocarbon & Chemical Process Industry
- Blending additives to process streams.
- Gas & liquid scurbbing
- Direct Steam heating
- Water & Wastewater Treatment
- pH samples and control
- Disinfection
- Polymer addition
- Food & Pharmaceutical Production
- Inline gas sparging
- Flavouring and coloring addition
- Syrup dilution
- Pulp & Paper Production
- Stock bleaching and blending
- Consistency control
- Direct steam heating
