Dehydration is the process of removing water vapor from the gas stream. It can be accomplished by several methods, but the process we are using is called glycol absorption. In this process, a hygroscopic liquid (glycol) is used to remove the water vapor from the gas in the tower.
Diethylene (DEG) and Triethylene (TEG) glycols are the two liquids normally used for gas dehydration. TEG is a liquid desiccant, a solvent that attracts and retains water at low temperatures but releases the water at high temperatures in the regen reboiler. Using TEG has following advantages:
TEG is more easily regenerated to a 98-99.5% solution in an atmospheric stripper because of its high boiling point and other physical properties. This permits high dew point depressions in the range of 80-140F.
Glycol Dehydration System is a liquid desiccant system is used for the removal of water from natural gas and natural gas liquid. It is the most common and economical means of water removal from these gases. The purpose of a glycol dehydration unit is to remove water from natural gas and natural gas liquids, when produced from a reservoir.
Solid Desiccant Dehydration
Solid-desiccant dehydration is the primary form of dehydrating natural gas using adsorption and usually consists of two or more adsorption towers, which are filled with a solid desiccant. Typical desiccants include activated alumina, silica gel, and molecular sieve.