Page 136 - Petroleum Production Engineering, A Computer-Assisted Approach

Guo, Boyun / Computer Assited Petroleum Production Engg 0750682701_chap10 Final Proof page 131 4.1.2007 8:26pm Compositor Name: SJoearun

SEPARATION SYSTEMS 10/131

14
OD, in.
12
3
10 /4
3
12 /4
Gas Capacity (MMscfd) 8 6 18
14
10
16
20
24

2 4

0
0 200 400 600 800 1,000 1,200 1,400 1,600
Operating Pressure (psia)
Figure 10.11 Gas capacity for packed glycol contactors based on 0.7-specific gravity at 100 8F (Sivalls, 1977).
14 ∇ t , 8F
Number of Valve Trays or Feet of Packing 10 55
d
12

65
75
8
85
95
6
4

2
0
0 1 2 3 4 5 6 7 8 9
Glycol to Water Ratio (gal TEG/lb H O)
2
m
Figure 10.12 The required minimum height of packing of a packed contactor, or the minimum number of trays of
a trayed contactor (Sivalls, 1977).

H t ¼ total heat load on reboiler, Btu/hr Glycol Flash Separator: A glycol flash separator is usually
installed downstream from the glycol pump to remove any
Equation (10.9) is accurate enough for most high-pres- entrained hydrocarbons from the rich glycol. A small 125-psi
sure glycol dehydrator sizing. A more detailed procedure vertical two-phase separator is usually adequate for this
for determination of the required reboiler heat load can be purpose. The separator should be sized based on a liquid
found from Ikoku (1984). The general overall size of the retention time in the vessel of at least 5 minutes.
reboiler can be determined as follows:
H t q G t r
A fb ¼ , (10:10) V s ¼ , (10:11)
7,000 60
where A fb is the total firebox surface area in squared feet. where
Glycol Circulating Pump: The glycol circulating pump can V s ¼ required settling volume in separator, gal
be sized using the glycol circulation rate and the maximum q G ¼ glycol circulation rate, gph
operatingpressureof the contactor.Commonlyusedglycol- t r ¼ retention time approximately 5 minute
powered pumps use the rich glycol from the bottom of the
contactortopowerthepumpandpumptheleanglycoltothe Liquid hydrocarbon is not allowed to enter the glycol-gas
top of the contactor. The manufacturers of these pumps contactor. If this is a problem, a three-phase glycol flash
should be consulted to meet the specific needs of the glycol separatorshould beusedtokeepthese liquid hydrocarbons
dehydrator. out of the reboiler and stripping still. Three-phase flash