Separations Challenges for Aqueous Separations

Transcription

1 Separations Challenges for Aqueous Separations Michael R. Ladisch, Rashid Bashir, Arun Bhunia, Youngmi Kim, Nathan Mosier Laboratory of Renewable Resources Engineering (LORRE) Purdue University Presented at 2008 AIChE meeting, Plenary Session I on Bioseparations: Celebrating 100 Years of Bioseparations, Philadelphia, PA Nov 17,

2 Acknowledgements Material in this work supported by: Agricultural Research Programs, Center for Food Safety Engineering, Purdue University USDA Cooperative Agreement ARS Eastern Regional Research Center, Dr. Jim Lindsay, Dr. Shu-I Tu ADM Rashid Bashir, Arun Bhunia, Richard Linton, Jaeho Shin, Youngmi Kim, Eduardo Ximenes, Linda Liu, Lisa Mauer Michael Ladisch is CTO of Mascoma Corporation 2

3 Outline Types of separations (two examples): Liquid / solids (food pathogens) Volatile Component (ethanol separation) Scale Microfluidic (food pathogens) High volume (fuel ethanol) Challenges in aqueous separations Low concentrations High throughputs Recovery Efficiency Regeneration / reuse of separations media

4 Acknowledgements Adam Wright, David Suang, Jaeho Shin, Nathaniel Frank, Peter McKinnis, Thomas kreke, Xingya (Linda) Liu, Andres Rodriguez Ok Kyung Koo, Kristin Burkholder, Balamurugan Jagadeesan, Sarimar Medina, and Krishna Mishra Priya Banada, Shantanu Bhattacharya, Yi-Shao Liu, Shuaib Salamat, Demir Akin

5 Food Safety Motivation: develop new knowledge, technologies, and systems to detect and prevent microbial and chemical contamination of foods

6 Motivation Detect low level of foodborne pathogen in complex and various foods and in quick and precise way Sample preparation is rate-limiting Couple to specific and rapid detection

7 Benchmarks (Goals) Concentrate sample containing bacteria Final concentration of 10 3 to 10 4 cells / ml Final viable cell count on chip > 10 cells Concentrate cells in 30 min Process samples in 60 min Maintain cell viability Introduce samples on chip, detect cells in 3 hr

8 CCR Method Cell Concentration and Recovery

9 CCR KiT Assembly Uses membranes in series to process 100 ml hot dog extract into 0.1 to 1 ml sample Air Space 47 mm filter holder 25 mm filter holder

10 Recovery Withdraw the liquid from the 25mm swinnex holder with the 3mL syringe Inject liquid in microcentrifuge tubes

11 Concentration through Filtration: Role of Liquid Film ~700 cells/ml X 50 ml Liquid film Syringe holder Assumption: 1mg=1 μl Membrane filter Each membrane contains ~15 μl of liquid By membrane filtration, 10 4 cells can be concentrated into a volume of 15 μl of liquid

12 Fluorescence Images Initial= 7.3x10 7 cells/ml x 50 ml=3.7 x 10 9 cells Blank Membrane E coli on P66 Membrane L. monocytogenes on P66 Membrane

13 SEM Images Initial= 7.3x10 7 cells/ml x 50 ml=3.7 x 10 9 cells Blank Membrane E coli on P66 Membrane L. monocytogenes on P66 Membrane

14 Petri-Dish on a Chip Measurement electrodes Outlet Inlet Microscope Objective DEP capture electrodes Microfluidic Tubes Microfluidic Tubes Wire-bond (with epoxy) PC board w. heater Edge Connector BioChip Bashir et al, 2006

15 Challenges Rapidly Concentrate Cells Control reduction of Flux During Filtration Keep cells viable Obtain small volume for introduction to Biochip Cell capture and chemistry in microfluidic devices

16 Dehydration of Ethanol Ethanol concentration from fermentation broth ranges from 8 to 13 % (by weight) Distillation enriches ethanol content to 92% or higher Adsorption processes break ethanol-water azeotrope and remove final amounts of water Starch based adsorbents selectively remove water from ethanol in an energy efficient manner

17 Corn Grit Adsorption Starch based adsorbent identified in 1978, and developed since then. Readily available, low cost, biodegradable, high selectivity to water an energy-efficient way to dehydrate ethanol Currently used as adsorbent in industry in a fixed bed adsorption systems for producing fuel-grade ethanol Beery et al., 2001, Bienkowski et al., 1985, Hong et al., 1982, Ladisch et al., 1979

18 Picture of Corn Grits

19 Ethanol Dehydration Process 99.6 % fuel grade ethanol CO 2 Fermentable Sugars 92% ethanol Yeast Corn Grits Corn Grits 10 % ethanol Fermentation Distillation Adsorption Desorption Regenerant Recycle

20 Goals Design, fabricate, and validate research scale corn grit adsorption system Simulate industrial scale adsorption system Evaluate conditions for use of corn grits as a desiccant

21 Corn Grit Adsorption System Apparatus H1 T4 Steam Generator PT1 HE1 PV4 TB RV2 PV5 P3 PT2 H 2 O/EtOH CO 2 Tank Pump 2 P1 P2 Flow Meter S CV1 CV2 SV2 PV3 Water Bath SV1 TW RV1 Adsorption Column DPT HE2 T5 Chilled Water Product B2 B1 T1 T2 T3 PV1 PV2 HE3 Feed H2 Steam Regenerant/Waste Feed/Product Chilled Water Pump 1 HE5 HE4 Regenerant Condensate

22 HE1 HE2 CO 2 Saturator HE1 Mass Flow Meter HE2 CO 2 Saturator Adsorption Bed Adsorption Bed CO 2 HE3 HE4,5 Waste

23 Data Monitoring Interface by VI Engineering

24 Breakthrough Run Shows Particle Size Effect 6% 5% Water % weight 4% 3% 2% 1% Corn Grits 2 (D p =1.7 mm) Corn Grits 1 (D p =1.4 mm) 0% Time (min)

25 Particle Size Effect Our system operates in the linear part of the adsorption equilibria. Only the surface of the particles actually come to equilibrium. Equilibrium constant is a function of particle size of adsorbent. a function of surface area of adsorbent. d 1 For linear part of the adsorption equilibrium q, amount adsorbed in equilibrium K 1 d 2 Adsorption is described by linear isotherm q=k C K 2 d 1 < d 2 C, water vapor conc. K 1 > K 2

26 Challenges Energy efficiency of water removal Balancing column pressure drop of small particles against adsorption capacity Model complex adsorption behavior (combined wave-front behavior)

27 Summary Challenges in aqueous separations Low concentrations High throughputs Recovery Efficiency Regeneration / reuse of separations media (sometimes not possible) Opportunity: Fundamental studies of biomolecules, bioproducts and microbes at surfaces