Page 161 - Gas Purification 5E

Ahnolamines for Hvdrogen Supde and Carbon Dioxide Renzoval 149

Table 2-25
Operating Data for Aqueous DGA Plants Treating Natural Gas

Plant A B-1 E2
~~ ~~ ~
Gas Feed Rate. MMscfd 6 121 83
Solution Flow rate, gpm 172 556 426
Solution Concentration, wt8 DGA 50 60 56.5
Feed Gas Analysis
HZS ~019 5.48 0.5-1.25 0.74
co-, vol8 6.52 1.5-3.75 3.46
Outlet Gas Analysis
HZS @/lo0 scf 0.205 4.25 0.01-0.05
cop VOlTi - <0.01 0.0093
Lean Solution Loading
H2S. gdgallon 2 -2 1
COz mole/mole amine 0.04 0.09
Rich Solution Loading
H2S mole/mole amine 0.09 0.06
C02 mole/mole amine 0.18 0.33
Absorber
No. of trays 25 20
Pressure, psig 140 550
Lean Solution Temp.,"F 120 88
Rich Solution Temp.,"F 156 171
Shipper
No. of trays, shipping 21 16
No. of rays, reflux 4 4
Pressure, psig 13 7.25
Reboiler temperature,"F 255 250
Soirees: Plant -4 data from Harbison and Dingman (1972j, Plant B-I data from Holder (19661,
Plant B-2 data courtesy Fluor Daniel (1995)

ethyl diet ha no la mine and Mixed Amine Plants

Ammons and Sitton (1981) describe an extensive series of tests conducted on a commer-
cial natural gas treating plant using aqueous MDEA to selectively remove H,S in the pres-
ence of a much larger concentration of C02 The approximate results of eight of the tests are
presented in Table 2-27. Although complete operating data are not given, the results are of
interest in showing the effects of MDEA concentration, solution flow rate, absorber tempera-
ture, and the number of active trays on the amount of C02 that passes through the absorber
unabsorbed (slippage). The results can be summarized as follows:
COz slippage increases with

1. Increased MDEA concentration (compare tests 1 and 2).
2. Decreased solution flow rate (compare tests 2 and 3? and also tests 6 and 8).