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10/132 EQUIPMENT DESIGN AND SELECTION
separators should be sized with a liquid retention time of 20– mccarthy, e.l., boyd, w.l., and reid, l.s. The water
30 minutes. The hydrocarbon gas released from the flash vapor content of essentially nitrogen-free natural gas
separator can be piped to the reboiler to use as fuel gas and saturated at various conditions of temperature and
stripping gas. Based on the glycol circulation rate and the pressure. Trans. AIME 1950;189:241–243.
operating pressure of the contactor, the amount of gas avail-
able from the glycol pump can be determined. mcketta, j.j. and wehe, w.l. Use this chart for water
content of natural gases. Petroleum Refinery
Stripping Still: The size of the packed stripping still for 1958;37:153–154.
the glycol re-concentrator can be determined based on the sivalls, c.r. Fundamentals of oil and gas separation.
glycol-to-water circulation rate (gas TEG=lb m H 2 O) and
the glycol circulation rate (gph). The required diameter for Proceedings of the Gas Conditioning Conference, Uni-
the stripping still is normally based on the required diam- versity of Oklahoma, Norman, Oklahoma, 1977.
eter at the base of the still using the vapor and liquid
loading conditions at the base point. The vapor load con-
sists of the water vapor and stripping gas flowing up Problems
through the still. The liquid load consists of the rich glycol
stream and reflux flowing downward through the still 10.1 Calculate the minimum required size of a standard
column. One tray is normally sufficient for most stripping oil/gas separator for the following conditions (con-
still requirements for TEG dehydration units. The amount sider vertical, horizontal, and spherical separators):
of stripping gas required to re-concentrate the glycol is Gas flow rate: 4.0 MMscfd
3
approximately 2---10 ft per gal of glycol circulated. Gas-specific gravity: 0.7
Condensate-gas ratio (CGR): 15 bbl/MMscf
Condensate gravity: 65 8API
Operating pressure: 600 psig
Summary
Operating temperature: 70 8F
Thischaptergivesabriefintroductiontofluidseparationand
gas dehydration systems. A guideline to selection of system 10.2 A three-stage separation is proposed to treat a well
componentsisalso presented.Operators needtoconsultwith stream at a flowline pressure of 1,000 psia. Calculate
equipment providers in designing their separation systems. pressures at each stage of separation.
10.3 Estimate water contents of a natural gas at a pressure
of 2,000 psia and temperatures of 40, 80, 120, 160,
References 200, and 240 8F.
10.4 Design a glycol contactor for a field dehydration
ahmed, t. Hydrocarbon Phase Behavior. Houston: Gulf installation to meet the following requirements. Con-
Publishing Company, 1989. sider both trayed-type and packed-type contactors.
campbell, j.m. Gas Conditioning and Processing. Norman,
OK: Campbell Petroleum Services, 1976. Gas flow rate: 10 MMscfd
guenther, j.d. Natural gas dehydration. Paper presented Gas-specific gravity: 0.65
Operating line pressure:
1,000 psig
at the Seminar on Process Equipment and Systems on Maximum working pressure 1,440 psig
Treatment Platforms, April 26, 1979, Taastrup, of contactor:
Denmark. Gas inlet temperature: 90 8F
guo, b. and ghalambor, a. Natural Gas Engineering Outlet gas water content: 7 lb H 2 O=MMscf
Handbook. Houston: Gulf Publishing Company, 2005. Design criteria with GWR ¼ 3 gal
ikoku, c.u. Natural Gas Production Engineering. New 99.5% TEG: TEG=lb m H 2 O
York: John Wiley & Sons, 1984.