1. Syngas fermentation to biofuel: Evaluation of carbon monoxide mass transfer and analytical modeling using a composite hollow fiber (CHF) membrane bioreactor

2. Syngas Synthesis gas Synthesis gas –Produced from the gasification of carbon-rich feedstock –Composed primarily of carbon monoxide and hydrogen –Can be converted to biofuels

3. Problems Syngas exists in a gaseous phase Syngas exists in a gaseous phase Microorganisms are in an aqueous phase Microorganisms are in an aqueous phase

4. Mass Transfer Implications Mass transfers occurs at several points: Mass transfers occurs at several points: –transfer of gas to gas-liquid interface –transfer of gas to liquid –transfer of gas to liquid around microorganism –diffusion of gas into microorganism Solubility of CO and H 2 are low Solubility of CO and H 2 are low Gas–liquid mass transfer is a rate-limiting step in syngas fermentation Gas–liquid mass transfer is a rate-limiting step in syngas fermentation

5. Previous Bioreactor Designs In order to increase mass transfer In order to increase mass transfer –Increase pressure –Increase gas-liquid surface area –Increase agitation –Alternative designs

6. This study Determine the mass transfer efficiencies of carbon monoxide in composite hollow fiber (CHF) membrane bioreactor Determine the mass transfer efficiencies of carbon monoxide in composite hollow fiber (CHF) membrane bioreactor

7. Setup CHF membrane bioreactor (3 liters) CHF membrane bioreactor (3 liters) Tap water (25°C) Tap water (25°C) Pure carbon monoxide Pure carbon monoxide

8. CHF Membrane Module Pressurized gas is forced through one side Pressurized gas is forced through one side Gas can pass through a nonporus layer Gas can pass through a nonporus layer Liquid cannot Liquid cannot

9. Experiment Measure volumetric mass transfer coefficient at varying Measure volumetric mass transfer coefficient at varying –Water recirculation rates (five) –Inlet carbon monoxide pressures (six)

10. Carbon Monoxide Determination Myoglobin (Mb)-protein bioassay Myoglobin (Mb)-protein bioassay

11. Results

12. Compared with other Bioreactors

13. Resistance Analysis

14. Model Used data to create a modeling equation using fluid dynamics Used data to create a modeling equation using fluid dynamics

15. Discussion Demonstrated the effectiveness of CHF membrane reactor Demonstrated the effectiveness of CHF membrane reactor

16. Problems Did not compare bioreactors consistently Did not compare bioreactors consistently Did not test with syngas Did not test with syngas Did not test the affect on microorganism Did not test the affect on microorganism

17. References Cussler, E. L. (2009). Diffusion, mass transfer in fluid systems. (3rd ed. ed.). Cambridge: Cambridge Univ Pr. Cussler, E. L. (2009). Diffusion, mass transfer in fluid systems. (3rd ed. ed.). Cambridge: Cambridge Univ Pr. Munasinghe, P. C., & Khanal, S. K. (2010). Biomass-derived syngas fermentation into biofuels: Opportunities and challenges. Bioresource technology, 101(13), 5013-5022. Munasinghe, P. C., & Khanal, S. K. (2010). Biomass-derived syngas fermentation into biofuels: Opportunities and challenges. Bioresource technology, 101(13), 5013-5022. Munasinghe, P. C., & Khanal, S. K. (2012). Syngas fermentation to biofuel: Evaluation of carbon monoxide mass transfer and analytical modeling using a composite hollow fiber (CHF) membrane bioreactor. Bioresource Technology, 112, 130-136 Munasinghe, P. C., & Khanal, S. K. (2012). Syngas fermentation to biofuel: Evaluation of carbon monoxide mass transfer and analytical modeling using a composite hollow fiber (CHF) membrane bioreactor. Bioresource Technology, 112, 130-136 Riggs, S. S., & Heindel, T. J. (2008). Measuring Carbon Monoxide Gas—Liquid Mass Transfer in a Stirred Tank Reactor for Syngas Fermentation. Biotechnology progress, 22(3), 903-906. Riggs, S. S., & Heindel, T. J. (2008). Measuring Carbon Monoxide Gas—Liquid Mass Transfer in a Stirred Tank Reactor for Syngas Fermentation. Biotechnology progress, 22(3), 903-906.