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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Slide 3

Membrane Unit

(sometimes called Permeation Unit) Permeate P i, perm P i, 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 4

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 5

Membrane Unit

R i



K i

*

Area

* (

P i

,

res



P i

,

surf

where: R i K i = Flowrate in std. vol/time = Permeation constant in vol/(time-area-pres) Area = Membrane area P i = Partial pressure of component i ) P i, perm P i, surf P i, res

Slide 6

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 7

Membrane Unit Oil Production with CO

2

Injection

Membrane CO 2 Recovery Fuel Gas CO 2 Makeup Condensate Well Production CO 2 Injection Oil/Gas Separator Oil Product

Slide 8

Membrane Unit

Flowsheet

Slide 9

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 Joule Thomson effect of the pressure drop.

Slide 10

Membrane Unit

Feed Stream Rate, 1000*scfh 377.5

Temperature, F 100.00

Pressure, psia 350.00

Molecular Weight Vapor Fraction 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

Slide 11

Membrane Unit

Feed Stream Rate, 1000*scfh 377.5

Temperature, F 100.00

Pressure, psia 350.00

Molecular Weight 41.3642

Vapor Fraction 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

Slide 12 N2 H2S CO2 C1 C2 C3 IC4 NC4 IC5 NC5 NC6 NC7

Membrane Unit

Vendor Supplied Permeability

R i



K i

*

Area

* (

P i

,

res



P i

,

surf

)

Component Permeability at 75 F scfd/ft3/psi

0.000499 0.008371 0.008366 0.000548 0.000323 0.000091 0.000027 0.000037 0.000028 0.000027 0.000021 0.000019

Permeability at 100 F scfd/ft3/psi

0.00065 0.009869 0.009858 0.000713 0.000418

0.000118 0.000035 0.000047 0.000028 0.000036 0.000029 0.000029

Slide 13

Membrane Unit

Permeability Fitted to Arrhenious Form

K i = K i,o exp[-E i /(RT)]

Component

N2 H2S CO2 C1 C2 C3 IC4 NC4 IC5 NC5 NC6 NC7

K i,o E i

0.1885

0.3337

0.3296

0.1985

33958 21146 21079 33809 0.1037

0.0306

0.0066

0.0099

33118 33375 32125 32125 0.00004116 2314.5

0.0081

0.0268

0.2194

32590 40960 53642 R = 10.73159, ft3-psia/R-lb-mol

Slide 14

Membrane Unit

Modeling Flowsheet

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Membrane Unit

Membrane Unit Icon

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Membrane Unit

Membrane Input

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Membrane Unit

Permeation Calculation

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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 19

Membrane Unit

Results