Some Applications about EGs:

Mono Ethylene Glycol (MEG)

Mono ethylene glycol is a commercially important raw material for manufacture of PET (poly ethylene terephthalate) polyester, one of ethylene glycols two major chemical uses which consumes large portion of total production.
Poly ethylene terephthalate polyester generally available at three different grades (fiber, film and bottle grade) is made from polymerization of MEG and DMT (di methyl terephthalate) or TPA (terephthalic acid). Their application in textile fibers and as a plastic for fabrication of soft drinks bottles and food packaging demonstrate their production importance in downstream industries.
Ethylene glycol’s other major uses, a non polymer one, is an antifreeze blending for liquid cooled motor vehicle to lower the freezing point when mixed with water.
Another significant industrial uses for MEG include use as a humectants, heat transfer liquid for coolant, air craft and runways deicing fluid, as a starting material for its ester and ether derivatives in plasticizer application, for glyoxal production and also is consumed as a softener and solvent and variety of other applications. Ethylene glycol is also used in adhesive, latex dyes, and asphalt water-based formulation to provide freeze protection.

The other application is using of MEG at gas field facilities. Before the gas is sent through the pipelines from the offshore to the onshore facilities, MEG is added to improve the gas flowability.

DEG is similar to MEG in many respects. It is used mainly as intermediate in production of unsaturated polyester resin and as an alcohol component in polyurethane manufacturing. DEG is blended into antifreeze and also is runway and aircraft deicing agent. Moreover, it is used for natural gas as a dehydration agent. Ester derivative of DEG serve as a plasticizer softener and surfactant.

Tri Ethylene glycol (TEG)

TEG has a similar property to DEG and is frequently preferred when a loss volatile compound is required. TEG is the preferred agent for drying natural gas and in other moisture removing applications. It is used for the same purpose as DEG, for example as solvent, humectants, a reactant in production of plasticizer, polyurethane and unsaturated polyester.