Reducing Glycol Losses in Gas Dehydration Unit
Author: G. Sharmila, Partha Sengupta, Barnali Das, A.S. Pawar and T. K. Banerjee
Abstract - Dehydration of natural gas is an essential process for gas transmission and in value addition process as it significantly reduces/ eliminates ice formation, clogging of lines by lowering the gas dew point. According to gas specs for pipeline transportation the maximum allowable water content in the gas stream should be 7 lb/mmscf. To meet these specifications, some of common methods used are absorption, adsorption, and membrane process. Out of these, absorption process based on Triethylene glycol (TEG) has gained acceptance worldwide and is also in use in ONGC at offshore platforms and Hazira Gas Processing Complex. In absorption process, natural gas is dehydrated by counter currently contacting lean glycol in an absorber column, and the rich glycol is regenerated in the regeneration section and circulated back to the absorber column. During this process there are chances of glycol losses in absorber and regeneration section. Glycol is a costly chemical and the loss of same will result in higher operating cost. This paper describes various opportunities for reducing glycol losses in Gas Dehydration Units (GDU).