Membrane Separations for Greener Operations in the...
Transcript of Membrane Separations for Greener Operations in the...
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