Membrane Separations for Greener Operations in the

Chemical Process Industries

C. Stewart Slater and Mariano J. SavelskiDepartment of Chemical Engineering

Rowan UniversityGlassboro, NJ

Session: Green Synthesis I13th Green Chemistry & Engineering Conference

College Park, MD June 23-25, 2009

Challenges and Opportunities

Process Challenge• Rising energy costs• Awareness of environmental footprint• Cost of capital investment (ROI)• Why change existing technology?Green Opportunities• Newer – energy efficient processes• Reduce waste• Waste/byproduct/material recovery

Membrane Processes

• Green alternative to process stream separations in the chemical process industries

• Product concentration, purification, waste minimization, chemical and solvent reuse and recovery

• Sustainable process - ability to recover water and valuable products from waste streams and save energy

Membrane Process

Reverse Osmosis Membrane ProcessesApplicability of membrane processes for green engineering

design in chemical manufacturing

• Applications:- Water purification for

synthesis/formulation- Water recovery in process

• Advantages:- Energy savings over

thermal processing (evaporation & distillation)

- Water reuse; water savings- Salt / reagent recovery

Water = blueSalt = red

Nanofiltration Membrane ProcessesApplicability of membrane processes for green engineering

design in pharmaceutical manufacturing

• Applications:– Solvent/API separations

• Advantages:– Energy savings over distillation– Solvent savings – no additional

recrystallization step– Solvent reuse; solvent savings– API recovery; increased yield– Avoid solvent disposal / solvent

thermal oxidation

Solvent = yellowyellowAPI = greenSalt = red

Microfiltration Membrane ProcessesApplicability of membrane processes for green engineering

design in beverage processing

• Applications:– Concentration / dewatering– “Cold” sterilization– Clarification / removal of

particulates• Advantages:

– Energy savings over evaporation

– Flavor retention– Energy savings over

Pasteurization– Capital cost savings

Beverage = blue Particles = red

www.tetrapak.com

Pervaporation Membrane ProcessesApplicability of membrane processes for green engineering design in fine chemical and pharmaceutical manufacturing

• Applications:- Selective solvent-water

separations / Dehydration- Azeotrope separations

• Advantages:- Energy savings over distillation- No entrainer (e.g., benzene)

needed for azeotropicseparations

- Solvent reuse; solvent savings- Avoid solvent disposal / solvent

thermal oxidation

Water = blueSolvent = green

www.sulzerchemtech.com

PV Process Integration

Solvent-water waste stream

Pervaporation

Dehydrated solvent for reuse

Solvent-water azeotropic mixture

Low flow rate stream: water with

some solvent

Typical Solvents• Isopropanol (az)• Ethanol (az)• Methanol• Ethyl acetate • Butyl acetate• Acetone• Acetronitrile (az)• Tetrahydrofuran (az)• n-Butanol• Methylethylketone (az)

Pharma IndustryCase Study 1 – Bristol-Myers Squibb

• Integration of PV technology with a Constant Volume Distillation (CVD) operation

• One step in synthesis of new oncology drug• Current process: Decrease water content in THF

solvent phase to 0.5%– Requires 13.9 kg THF/kg API

7.85 kg THF entrainer/kg API– Generates 9.2 kg Waste/kg API

• LCI / LCA analysis indicates emissions are significant based on solvent life cycle

Proposed CVD – PV Hybrid Process

Basis: 68 kg API / batch

6.1 kg THF/kg API0.65 kg Waste/kg API0 kg THF Entrainer/kg API

Savelski, Slater, Carole, 8th Inter. Conf. EcoBalance, Tokyo, Japan, December 2008.

Life Cycle Inventory Comparison

Waste Disposal23%

THF Manufacture77%

Steam<0.1%

Waste Disposal40%

Steam54%

Electricity6.0%

Total CVD Emissions: 89 kg waste/kg API

Total CVD‐PV Emissions: 3.8 kg waste/kg API

Savelski, Slater, Carole, 8th Inter. Conf. EcoBalance, Tokyo, Japan, December 2008.

• Integration of PV unit to current CVD process produces a greener process– Elimination of THF entrainer– Process waste reduced by 8.55 kg waste / kg API– Total life cycle emissions reduced by 85.2 kg waste / kg API

(96% reduction)

• Process capital acquisition not cost efficient at pilot scale– Need to produce 12,000 kg API /yr to be economically feasible

for capital investment

Pharma IndustryCase Study 1 – Bristol-Myers Squibb

Savelski, Slater, Carole, 8th Inter. Conf. EcoBalance, Tokyo, Japan, December 2008.

Pharma IndustryCase Study 2 - Pfizer

• Investigation of solvent recovery alternatives to reduce solvent waste in celecoxib process

• IPA solvent recovery from final purification steps

• Integration of pervaporation with distillation using existing equipment inventory

Slater, Savelski, Hounsell, Pilipauskas, Urbanski, Proc 2008 Mtg Amer Instit Chem Eng, Philadelphia, PA, November 2008,

Centrifuge

IPA / Water Washes50% IPA

50% Water IPA / Water Washes

49.2% IPA49.6%  H2O0.71% MeOH and EtOH0.5% TDS

Mother Liquor

34.5% IPA45.2%  H2O8.45% MeOH2.71% EtOH9.10% TDS

Dryer

Wet Product Solids

Dryer Distillates

50.7% IPA48.8% H2O0.47% MeOH and EtOH0% TDS

Celecoxib

Conc. &  Sell ML

Recovery

SolventsWaterAPI

Other

Proposed Distill-PV-Distill Process

• Purification for only part of waste stream– Centrifuge wash and Dyer distillates for recovery– Mother liquor for (sale) use as generic solvent

• Overall 57% IPA recovered @ 99.1 wt% for reuse in process• Utilities:10,000 kg/batch of steam, 59 kWh/batch of electricity, and 91,200

gal/batch of cooling water

Slater, Savelski, Hounsell, Pilipauskas, Urbanski, Proc 2008 Mtg Amer Instit Chem Eng, Philadelphia, PA, November 2008,

A design basis of 1000 kg waste/hr is used for illustrative purposes

Life Cycle Inventory Comparison

IPA Manufacture40%

Incineration60%

ML Distillation

19%

IPA Manufacture

59%

Dist‐PV‐Dist22%

Total Base Case Emissions: 29.5 kg waste/kg API

Total Dist‐PV‐Dist Emissions:2.4 kg waste/kg API

Slater, Savelski, Hounsell, Pilipauskas, Urbanski, Proc 2008 Mtg Amer Instit Chem Eng, Philadelphia, PA, November 2008,

~92% decrease in total emissions

Annual Operating Costs

-1,000,000

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

Base Case Distil-PV-Distil-Sell ML

Design Case

Annu

al C

ost

ML Concentrate saleMembrane ModulesOperating LaborMaintenanceCooling WaterElectricitySteamWaste DisposalFresh IPA

72% Annual Cost Savings

Recovers 57% of IPA from waste for potential reuse

$5.28 MM

$1.46 MM

Slater, Savelski, Hounsell, Pilipauskas, Urbanski, Proc 2008 Mtg Amer Instit Chem Eng, Philadelphia, PA, November 2008,

Vibratory Field Membrane ProcessesApplicability of membrane processes for green engineering

design in food processing

• Applications:– Fluid-particle separations

• Advantages:– Efficient fluid clarification– Low fouling, enables continuous

operation– Waste disposal reduction– Operating cost reduction

Water = blueParticulates = red

www.vsep.com

Food IndustryCase Study 3 - Pillsbury / General Mills

• Water change required in bagel "cooker"–Protein waste and particulates

• Objective:–Reduce wastewater–Save water–Extend “cooker” life

ProductionLine

Feed

Concentrate for “Animal Feed”

Purified water recycled to cooker

V-Sep Membrane

Comparison of V-Sep to conventional technologies

• Capital costs less than for evaporators and rotary drum filter/concentrators

• Energy is less than evaporators, centrifuges, filter presses

• Accommodates wider range of feed flow and particulate size distributions

• Flux and selectivity maintained –elimination of cleaning chemicals

www.komline.com

Food IndustryCase Study 3 - Pillsbury / General Mills

• Cooker life doubled• Energy used to heat water saved = 1.28x108 Btu/yr• Water utilization saved = 110,000 gal/yr• Wastewater disposal saved = 110,000 gal/yr• Operating cost saved (Cooker cleaning, production

loss, waste disposal, etc) = $246,300/yr• Savings multiplied when applied to all production

lines• Potential to triple cooker life with combined V-Sep

and Centrifugation process

Summary

• Membrane processes are a viable alternative in process stream separation

Green advantage• Cost effective

–Operating–Capital

• Solvent / by-product recovery• Waste minimization• Easily integrated into process

Acknowledgements

• Bristol-Myers Squibb

• General Mills / Pillsbury

• Pfizer

• U.S. Environmental Protection

Agency P2 grant #NP97257006-0