SSE-02 Using the Membrane Unit in PRO/II New Application Brief U-2

Slide 1

© 2012 Invensys. All Rights Reserved. The names, logos, and taglines identifying the products and services of Invensys are proprietary marks of Invensys or its subsidiaries. All third party trademarks and service marks are the proprietary marks of their respective owners.

SSE-02Using the Membrane Unit in PRO/IINew Application Brief U-2

Bernie Unger

North American User GroupOctober 14-16

Slide 3

Membrane Unit (sometimes called Permeation Unit)

Residue

Permeate

Pi, res

Pi, perm

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

)(** ,, surfiresiii PPAreaKR where:

Ri = Flowrate in std. vol/timeKi = Permeation constant in vol/(time-area-pres)Area = Membrane area Pi = Partial pressure of component i

Pi, res

Pi, surf

Pi, perm

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 UnitOil Production with CO2 Injection

Oil/Gas Separator

Oil Product

Condensate

Fuel Gas

Membrane CO2 Recovery

Well ProductionCO2 Injection

CO2 Makeup

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 41.3642 Vapor Fraction 1.000

Molar Composition 1 - N2 0.0100 2 - H2S 1.5000E-03 3 - CO2 0.8500 4 - C1 0.0955 5 - C2 0.0150 6 - C3 0.0100 7 - IC4 5.0000E-03 8 - NC4 5.0000E-03 9 - IC5 5.0000E-03 10 - NC5 1.0000E-03 11 - NC6 1.0000E-03 12 - NC7 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 0.0100 2 - H2S 1.5000E-03 3 - CO2 0.8500 4 - C1 0.0955 5 - C2 0.0150 6 - C3 0.0100 7 - IC4 5.0000E-03 8 - NC4 5.0000E-03 9 - IC5 5.0000E-03 10 - NC5 1.0000E-03 11 - NC6 1.0000E-03 12 - NC7 1.0000E-03

Slide 12

Membrane Unit Vendor Supplied Permeability

Component Permeability Permeability at 75 F at 100 Fscfd/ft3/psi scfd/ft3/psi

N2 0.000499 0.00065 H2S 0.008371 0.009869 CO2 0.008366 0.009858 C1 0.000548 0.000713 C2 0.000323 0.000418C3 0.000091 0.000118 IC4 0.000027 0.000035 NC4 0.000037 0.000047 IC5 0.000028 0.000028 NC5 0.000027 0.000036 NC6 0.000021 0.000029 NC7 0.000019 0.000029

)(** ,, surfiresiii PPAreaKR

Slide 13

Membrane Unit Permeability Fitted to Arrhenious Form

Component Ki,o Ei

N2 0.1885 33958H2S 0.3337 21146CO2 0.3296 21079C1 0.1985 33809C2 0.1037 33118C3 0.0306 33375IC4 0.0066 32125NC4 0.0099 32125IC5 0.00004116 2314.5NC5 0.0081 32590NC6 0.0268 40960NC7 0.2194 53642

Ki = Ki,o exp[-Ei /(RT)]

R = 10.73159, ft3-psia/R-lb-mol

Slide 14

Membrane Unit Modeling Flowsheet

Slide 15

Membrane Unit Membrane Unit Icon

Slide 16

Membrane Unit Membrane Input

Slide 17

Membrane Unit Permeation Calculation

Slide 18

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