Hybrid Distillation – Membrane Process to Increase Capacity and Reduce Costs

for Production of Propylene and Ethylene

AIChE Annual MeetingSalt Lake City, UT, November 8-13, 2015

Sudip Majumdar, Yosuke Koizumi, Ken Loprete, Evan Sohodski, Ken Pennisi, Stuart Nemser

Compact Membrane Systems, Wilmington, DEwww.compactmembrane.com

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Overview

• Opportunity for Olefin-Paraffin Separation• 30 Year Membrane History• CMS Stable Facilitated Transport Membrane• Preliminary Scale-Up• Engineering and Economic Evaluation• Path Forward

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Olefins are Big

Chemical Production*(1x106 lbs)

Nitrogen / Oxygen 69,600 / 58,300Ethanol 66,100Ethylene 52,900Propylene 31,100Ammonia 22,700Chlorine / Sodium Hydroxide 21,500 / 16,600Ethylene Dichloride 19,400Benzene 13,300Ethylene Oxide 5,900Acetone 3,200* 2010 Production of top 10 chemicals

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Ethylene and Propylene Product Chains

Membrane Can Touch Olefins Multiple Times

• Refinery (+ New on Purpose Propylene Sites)

• Polymer Purge Line

• Polymer Silo

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Experimental Upper Bound Based on Pure Propylene and Propane Permeation Data

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Ref: Burns and Koros, Journal of Membrane Science, 211, 299 (2003)

Historically Membranes for Olefin-Paraffin are Not Stable

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Ref: Merkel et al., Journal of Membrane Science 447, 177 (2013)

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Commercial Amorphous Fluoropolymers

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Teflon AF HyflonCytop

Facilitated Transport(Fixed Carriers)

OlefinParaffin

Facilitated Transport

Solution-Diffusion

Carrier

9Adapted from Cussler E.L.: Facilitated Transport. In: Membrane Separation Systems, vol. 2, US DOE Report, DOE/ER/30133-H1 (1990)

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Custom Amorphous Fluoropolymer (CAF)and

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• Silver is part of the polymer chain• Form stable, high flux, high selectivity

facilitated transport membranes• CAF and new synthesis procedure

potentially protects silver

Variation of Humidity

0

25

50

75

100

125

150

0

50

100

150

200

250

300

0 20 40 60 80 100

Sele

ctiv

ity

Prop

ylen

e Pe

rmea

nce

(GPU

)

Overall Humidity (%)

PermeanceSelectivity

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Effect of Feed Concentration

0

100

200

300

400

0 20 40 60 80 100

Prop

ylen

e Pe

rmea

nce

(GPU

)

Propylene Feed Concentration (Vol%)

Bot

tom

of C

3Sp

litte

r

Top

of C

3Sp

litte

rPo

lypr

opyl

ene

Rea

ctor

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Stable, Strong Performance Over Time

0

50

100

150

200

250

300

10 20 30 40 50 60 70 80

C3H

6Pe

rmea

nce

(GPU

) /

C3H

6-C3H

8Se

lect

ivity

Duration (Days)

Long Term Stability in Presence of SulfurC3H6 Permeance

C3H6-C3H8 Selectivity

Selectivity is a function of

feed stream composition and ranges

from~30 -80

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Ethylene-Ethane Mixture Separation

Olefin Permeance(GPU)

Paraffin Permeance(GPU) Selectivity

Ethylene / Ethane 275.5 3.6 76.2

Propylene /Propane 226.5 3.2 70.2

Feed: 20% Olefin - 80% Paraffin; Feed Pressure: 60 psig; Humidified Feed/Sweep; New Membrane

Preliminary Membrane Scale-up(47 mm Disc vs. 10 inch Square)

Propylene Permeance

(GPU)

SelectivityC3H6/C3H8

256 17.0 10”

10”

47 mm Disc Results

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Feed: 20% C3H6 - 80% C3H8Feed Pressure: 60 psig

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Permeance and Selectivity Map of CMS Membranes

CMSMembranes

Engineering and Economic Evaluation

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Key Assumptions: C3 Splitter Analysis

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Membrane Permeance (Propylene) 100 GPUMembrane Selectivity 20Feed Pressure 110 psiaPermeate Pressure 14.7 psiaMembrane Replacement Rate 33% per yearC3 Splitter Feedstock 50% PropyleneValue of Splitter Feed 21 cents/lbPrice of HD05 Propane 24.5 cents/lbPrice of Propylene 60 cents/lb

Distillation-Membrane Hybrid ProcessesConfiguration 2Configuration 1

• Membrane separates distillate• Retentate recycled to column• Reduces column top product purity required• Reduces reflux ratio required & saves

energy• Enables higher feed flow rate to column for

greater propane & propylene production

• Membrane separates bottom fraction• Permeate recycled to column • Very small increase in flood factor ~1%• Increases propane purity and

propylene yield

Tower

Propylene/PropaneFeed

PropyleneVapor

95% Propane

Distillation Column

Membranes

99.5% Propylene

Vacuum Pump& 2-stage intercooled

compressor

Compressor w aftercooler

Superheater

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0

2

4

6

8

10

12

14

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20

0%

25%

50%

75%

100%

125%

150%

175%

200%

225%

250%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Payb

ack

Perio

d (m

onth

s)

Inte

rnal

Rat

e of

Ret

urn

Case

Payback IRR

Selectivity

35 50

Base Steam & Electricity

Price-50% +50%

Propane/Propylene

Price-20% +20%

Replace Rate

25% 50%

Permeance

75 85

Propane & Energy Price

-20% +20%

Feed Value

-15% +15%

Membrane Completing Separation of HD10 Propane at Bottom of C3 Splitter with Propylene Capacity of 40,000 Tons per Year

Membrane System for Propylene Recovery from Polypropylene Reactor Purge

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Base Case Economics

Payback Months

C3 Splitter ~ 11

Polypropylene Reactor Purge ~ 8

Summary / Path Forward

CMS Demonstrated Stable Olefin-Paraffin Facilitated Transport Membrane

Attractive C3 Splitter Economics Payback < 15 months

Key Next Steps Optimize Process – 2016 Build Larger Membrane Modules – 1H / 2016 Demonstrate at Plants – 2H / 2016 - 2017

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The authors gratefully acknowledge the support of the US Department of Energy through Small Business Innovation Research (SBIR) Awards.

Acknowledgement

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