rich amine loading

[eilma]

hi everybody
I am working in gas refinery in engineering department.can you help me?
i faced a problem in Gas Sweetening and Processing Field book.
in page 133 in this book,after was calculated DEa circulation,author for heat balance calculation,was calculated co2 and h2s mole absorbed in rich amine.
for declare this problem,i explain his example:
Amine Processing
Unit (DEA)
Gas volume = 120,000 std m3/h
Gas gravity = 0.67 SG (Air ¼ 1.0)
Pressure = 7000 kPa (A)
Gas temperature = 38 C
CO2 inlet = 4.03%
CO2 outlet = 2%
H2S inlet =19 ppm ¼ 0.0019%
H2S outlet = 4 ppm
Max. ambient temp = 38 C

LDEA = 192QgXA/c*solution density*AL

c=amine weight fraction, kg amine/kg
solution

AL=acid gas loading, mole acid gas/mole
amine
LDEA =DEA circulation rate, m3/h
Qg = gas flow rate, std m3/h
XA = required reduction in total acid gas
fraction, moles acid gas removed/
mole inlet gas. Note: XA represents
moles of all acid components, that is,
CO2, H2S, and Meracaptans, as MEA
and DEA are not selective

LDEA= 4:39 *120,000*0.04032/(0:35*1045*0.50)=116 m3/h
Add 10% for safety = 128 m3/h

moles CO2
absorbed =(120,000 std m3/h * 0.04032)/10.87std/m3
=445
note:[highlight #75507B]10.87?????? How were obtained?[/highlight][/highlight]

10.87 was used for H2S too?? I am confuse for it?
also,for calculation co2 absorbed,2% co2 outed from tower,but was calculated in rich amine????why??
plz,may you check in example.
tnk you for regard

 

[georgeverghese]

The attachment is all blank...

Looking at your posting only, agree the moles of CO2 removed per hour should be 120e3*(0.0403-0.02)/23.69 = 103kgmoles/hr

And DEA circulation rate should also account for the CO2 not removed, so circ rate = 103/(0.35*1045*0.5/105)= 59m3/hr of 35%wt DEA solution.

 

[eilma]

hi dear
tank you for your answer
your solution,23.69??
do you mean 22.414 L/mol???for ideal gas

 

[georgeverghese]

Yes, 1.0kgmole of gas at ideal conditions = 22.414Nm3/hr (ref 1atm, 0degC) = 23.69Sm3/hr(ref 1atm, 15.6degC).