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

1
Syngas fermentation to biofuel Evaluation of
carbon monoxide mass transferand analytical
modeling using a composite hollow fiber (CHF)
membrane bioreactor
2
Syngas

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

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Problems

• Syngas exists in a gaseous phase
• Microorganisms are in an aqueous phase

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Mass Transfer Implications

• 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 H2 are low
• Gasliquid mass transfer is a rate-limiting step
  in syngas fermentation

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Previous Bioreactor Designs

• In order to increase mass transfer
• Increase pressure
• Increase gas-liquid surface area
• Increase agitation
• Alternative designs

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This study

• Determine the mass transfer efficiencies of
  carbon monoxide in composite hollow fiber (CHF)
  membrane bioreactor

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Setup

• CHF membrane bioreactor (3 liters)
• Tap water (25C)
• Pure carbon monoxide

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CHF Membrane Module

• Pressurized gas is forced through one side
• Gas can pass through a nonporus layer
• Liquid cannot

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Experiment

• Measure volumetric mass transfer coefficient at
  varying
• Water recirculation rates (five)
• Inlet carbon monoxide pressures (six)

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Carbon Monoxide Determination

• Myoglobin (Mb)-protein bioassay

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Results
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Compared with other Bioreactors
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Resistance Analysis
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Model

• Used data to create a modeling equation using
  fluid dynamics

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Discussion

• Demonstrated the effectiveness of CHF membrane
  reactor

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Problems

• Did not compare bioreactors consistently
• Did not test with syngas
• Did not test the affect on microorganism

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References

• 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. (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 GasLiquid Mass Transfer in a
  Stirred Tank Reactor for Syngas Fermentation.
  Biotechnology progress, 22(3), 903-906.