ABSTRACT:

All glycols used for dehydration by absorption in counter current Tri-ethylene glycol (TEG), and Mono-ethylene glycol (MEG) used for glycol injection for hydrate prevention will require reclaiming. The intervals at which reclaiming is required will vary from a month or two for very foul solutions to a year or more for those that are properly conditioned in the course of operation. It should be remembered that glycol solutions are small in quantity compared to the multi-millions cubic meter of gas and condensate that they contact. Contaminants such as salts, lube oil, hydrocarbon condensate, crude oil and corrosion products are present in abundance in liquid phase and in minute "trace" amount in the gas; and they continually plague operators in their glycol systems, and the symptoms of these problems are fouled equipment, foaming in the system resulting in expensive glycol losses, and insufficient process capability. Shutting a plant down to thoroughly clean and repair all the equipment is a periodic necessity and very expensive. MEG catches most contaminants and they accumulate in the plant's glycol inventory until they create severe operational problems. Most operators drain the contaminated glycol charge and discard it, replacing it with a charge of new glycol. This begins a new cycle that ends in the same way month(s) later. Other plants lose so much contaminated glycol in "normal operations that replacing the losses with new glycol keeps the contamination at a tolerable level due to continuous addition of "makeup" glycol.

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