Calculation of dehydration absorbers based on improved phase equilibrium data
Dehydration using triethylene glycol (TEG) as an absorbent, is a standard process for natural gas treating. New and more accurate TEG/water equilibrium data have been measured between 1980 and 1990. However, this has not influenced much on the design methods of dehydration absorbers. Inaccurate equilibrium data have been extensively used in design calculations. When using data from a common source like Worley, an overall bubble cap tray efficiency between 25--40% has normally been recommended. This has resulted in a quite satisfactory and consistent design method. It is obvious that newer equilibrium data (Herskowitz, Parrish, Bestani) are more accurate. However, to achieve an improved design method, column efficiencies consistent with the new equilibrium data must be recommended. New equilibrium data have been correlated to an activity coefficient model for the liquid phase and combined with an equation of state for the gas phase. Performance data from the North Sea offshore platform Gullfaks C (drying 4--5 MMscmd) have been measured. The bubble cap column has been simulated, and the tray efficiency has been adjusted to fit the performance data. Tray efficiencies calculated with new equilibrium data are higher than 50%. Calculated tray efficiency values are dependent on the equilibrium data used. There are still uncertainties in equilibrium data for the TEC/water/natural gas system. When using accurate equilibrium data, an overall bubble cap tray efficiency of 40--50% and a Murphree efficiency of 55--70% can be expected at normal absorption conditions.
- Research Organization:
- Telemark Inst. of Tech., Porsgrunn (NO)
- OSTI ID:
- 20000882
- Report Number(s):
- CONF-990331-
- Resource Relation:
- Conference: Gas Processors Association Seventy-Eighth Annual Convention, Nashville, TN (US), 03/01/1999--03/03/1999; Other Information: PBD: 1999; Related Information: In: Gas Processors Association seventy-eighth annual convention, proceedings, 393 pages.
- Country of Publication:
- United States
- Language:
- English
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