Gas Processing & Treating (Midstream)

Dehydration is the process of removing water vapor from the gas stream. It can be accomplished by several methods, but the process Forum uses 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.
• TEG has an initial theoretical decomposition temperature of 404F while the degradation temperature of diethylene glycol is only 328F
• The evaporation losses are lower for TEG than DEG.
• Simpler regeneration equipment is required.
• Dehydration operating and capital costs are lower than with DEG.

A Gas Dehydration Unit consist of contactor / absorber (tower) and regenerator / reconcentrator (regen). Forum offers two kinds of towers, the Bubble Cap Tray (BCT) and Packed tower. By providing your design conditions and project strategy our engineers will help you determine which tower design you need to optimize your project.

Forum can manufacture gas dehydration towers for flowrates from 10MM (16” OD) to 250MM (72”ID) and five standard regens from 500K to 2.0MM BTU/HR. For more complex applications Forum offers custom regens up to 6.0MM BTU/HR with a variety of options to meet our customer’s requirements.