In glycol dehydration unit , why we use mostly triethylne glcol, instead of biethylene or monoethlene glycol?

As tertiary Glycol absorb ad desorb ( reversible reaction ) easily due to max valence and regenerate easily  ,  while biethylene or monoethlene glycol having the addition reaction so water after addition  non reversible and products cannot regenerate .

because it has more hydroxyl groups and higher density so the miscibility with the water and the hydrophility properties with the hydrocarbons to not trap any hydrocarbons

Triethylene contain more carbon than specified biethylene or monoethyle provide more energy and more cracking biproduct

cost of operating are lower

• triethylene glycol (TEG) is the most commonly used glycol for dehydration of natural gas because of the advantages relative to diethylene glycol (DEG) & monoethylene glycol (MEG):

  • TEG is more easily regenerated to a higher degree of purity
  • Vapor losses are lower
  • Operating costs are lower