PPT Template

Report
Slide 1
SSE-02
Using the Membrane Unit in PRO/II
New Application Brief U-2
Bernie Unger
North American User Group
October 14-16
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Membrane Unit
(sometimes called Permeation Unit)
Pi, perm
Permeate
Pi, res
Residue
 A simple model to simulate components that can migrate selectively across a
membrane.
 Composed of a bundle of hollow fibers.
 Flow passes from the high pressure feed/residue side to the low pressure
permeate side of the fiber
Slide 3
Membrane Unit
Assumptions
 Constant total pressure on both the permeate and feed/residue side
 The driving force is partial pressure as calculated by ideal gas law
 The permeate side gas is continually swept away from the
membrane
Slide 4
Membrane Unit
Ri  Ki * Area* (Pi,res  Pi,surf )
where:
Ri = Flowrate in std. vol/time
Ki = Permeation constant in vol/(time-area-pres)
Area = Membrane area
Pi = Partial pressure of component i
Pi, perm
Pi, surf
Pi, res
Slide 5
Membrane Unit
Solution technique
 Integrate on dArea
Solution characteristics
 Based on partial pressure, not fugacity, therefore solutions do not
change with change in thermo method
 Limiting case of small area: Flowrate can be calculated from
product partial pressures
 Because permeate is continually carried away from the membrane,
a membrane unit with 10 area units will have the exact same
performance as ten 1 area unit membrane units in series.
Slide 6
Membrane Unit
Oil Production with CO2 Injection
Membrane CO2 Recovery
Fuel Gas
CO2 Makeup
Condensate
CO2 Injection
Well Production
Oil/Gas
Separator
Oil Product
Slide 7
Membrane Unit
Flowsheet
Slide 8
Membrane Unit
Flowsheet considerations
 The fuel gas is consumed on plant to drive process equipment.
 The fuel gas is targeted to 900 Btu/scf for proper equipment
operation.
 The pressure of the permeate side of the membrane units is adjusted
to achieve the heat content.
 The pressure drop across the residue side is negligible.
 Two membrane shells are included to allow intermediate condensate
dropout.
 The temperature equilibrates between the permeate and the residue.
The product streams have a lower temperature because of the JouleThomson effect of the pressure drop.
Slide 9
Membrane Unit
Feed Stream
Slide 10
Rate, 1000*scfh
Temperature, F
Pressure, psia
Molecular Weight
Vapor Fraction
377.5
100.00
350.00
41.3642
1.000
Molar Composition
1 - N2
2 - H2S
3 - CO2
4 - C1
5 - C2
6 - C3
7 - IC4
8 - NC4
9 - IC5
10 - NC5
11 - NC6
12 - NC7
0.0100
1.5000E-03
0.8500
0.0955
0.0150
0.0100
5.0000E-03
5.0000E-03
5.0000E-03
1.0000E-03
1.0000E-03
1.0000E-03
Membrane Unit
Feed Stream
Slide 11
Rate, 1000*scfh
Temperature, F
Pressure, psia
Molecular Weight
Vapor Fraction
377.5
100.00
350.00
41.3642
1.000
Molar Composition
1 - N2
2 - H2S
3 - CO2
4 - C1
5 - C2
6 - C3
7 - IC4
8 - NC4
9 - IC5
10 - NC5
11 - NC6
12 - NC7
0.0100
1.5000E-03
0.8500
0.0955
0.0150
0.0100
5.0000E-03
5.0000E-03
5.0000E-03
1.0000E-03
1.0000E-03
1.0000E-03
Membrane Unit
Vendor Supplied Permeability
Ri  Ki * Area* (Pi,res  Pi,surf )
Slide 12
Component
Permeability
at 75 F
scfd/ft3/psi
Permeability
at 100 F
scfd/ft3/psi
N2
H2S
CO2
C1
C2
C3
IC4
NC4
IC5
NC5
NC6
NC7
0.000499
0.008371
0.008366
0.000548
0.000323
0.000091
0.000027
0.000037
0.000028
0.000027
0.000021
0.000019
0.00065
0.009869
0.009858
0.000713
0.000418
0.000118
0.000035
0.000047
0.000028
0.000036
0.000029
0.000029
Membrane Unit
Permeability Fitted to Arrhenious Form
Ki = Ki,o exp[-Ei /(RT)]
Component
Ki,o
Ei
N2
H2S
CO2
C1
C2
C3
IC4
NC4
IC5
NC5
NC6
NC7
0.1885
0.3337
0.3296
0.1985
0.1037
0.0306
0.0066
0.0099
0.00004116
0.0081
0.0268
0.2194
33958
21146
21079
33809
33118
33375
32125
32125
2314.5
32590
40960
53642
R = 10.73159, ft3-psia/R-lb-mol
Slide 13
Membrane Unit
Modeling Flowsheet
Slide 14
Membrane Unit
Membrane Unit Icon
Slide 15
Membrane Unit
Membrane Input
Slide 16
Membrane Unit
Permeation Calculation
Slide 17
Membrane Unit
Solution Technique
 Calculators are used to set permeation coefficients. It iteratively retrieves
temperature from the membrane unit and recalculates the coefficients based
on temperature.
 A controller is used to adjust the pressure of the permeate to achieve the
heat content of the fuel gas.
Slide 18
Membrane Unit
Results
Slide 19

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