Brian McConnell and Brendan Nichols Faculty Mentor: Dr. Ihab Farag Biodiesel Lab, 103 Morse Hall. Fri April 26, 2013

Transcription

1 Kinetics of Lipid Extraction From Microalgae Brian McConnell and Brendan Nichols Faculty Mentor: Dr. Ihab Farag Biodiesel Lab, 103 Morse Hall Fri April 26, 2013

2 Overview Background Goals/Objectives Experimental Setup Results & Analysis Conclusions Recommendations

3 Algae Growth, Drying and Lipid/Oil Extraction water Hexane algae nutrients water air Growth & Monitoring Oil-rich algae + water Dewatering dry oil-rich algae Lipid/Oil Extraction light algae Oil/Lipid

4 Algae Growth in 80L Tanks Day 0 Day 4 Day 9 Day 14

5 Algae Growth, Drying and Lipid/Oil Extraction water Hexane algae nutrients water air Growth & Monitoring Oil-rich algae + water Dewatering dry oil-rich algae Lipid/Oil Extraction light algae Oil/Lipid 2.5 weeks of work 50 g of dry algae We produced about 200 g for extraction work

6 Goals Select a less toxic solvent for algal oil extraction. Investigate how the operating conditions affect the algae oil extraction speed and the yield of the extracted algae oil. Optimize the algae oil extraction process.

7 Solvent Selection Hexane is C H, nonpolar solvent 6 14 Heptane is C H, nonpolar 7 16 solvent

8 Hexane vs Heptane Hexane Heptane Toxicity to the peripheral nervous system very toxic slightly toxic Boiling Point (1 atm) 68 C 98 C Vapor Pressure (25 C) 17.3 kpa 5.3 kpa Energy Required to Boil from 20ºC 475 kj/kg 493 kj/kg Cost (FisherSci, 4L) $238 $404 Effectiveness Very Effective To be determined Takeuchi et al. A comparative study on the neurotoxicity of n-pentane, n-hexane, and n-heptane in the rat. British Journal of Industrial Medicine August; 37(3):

9 g Oil Extracted/ 100 g algae Investigate how the operating conditions affect the algae oil extraction speed and the yield of the extracted algae oil. Proposed Kinetics Model Max Yield for Process 1.0 Time Constant Tau > 1 Slow Process Tau=1 Tau<1 Fast Process Time (min)

10 Objectives Compare hexane and heptane as solvent for extraction Determine the maximum yield (K) and time constant (τ) of the extraction for solvent-to-algae ratios of 5:1 and 30:1 for hexane and heptane.

11 Experimental Setup Algae Oil Extraction Dry Algae Solvent Hot Water Bath To Ensure Solvent Refluxes

12 Experimental Setup Solvent Filtration and Evaporation Algae + Oil + Solvent Solvent Evaporation 5 to 6 hours Algae Removal Filtered Oil + Solvent Hexane Algae Oil

13 Absorbance Results Filtered Oil + Solvent Absorbance nm The curves are very similar so the solvents extract very similar material Hexane Heptane Wavelength (nm)

14 Results Extraction Trials 2 replicates performed for each extraction time = 32 total trials Hexane

15 g Oil extracted/ 100 g algae Results Hexane 5:1 Solvent:Algae Ratio : τ = 10min, K = 2.75g/ 100g algae Time (min) Hexane

16 g Oil extracted/ 100 g algae Results Hexane 30:1 Solvent:Algae Ratio Time (min) Hexane 30:1 τ = 20min, K = 3.90g/ 100g algae

17 g Oil extracted/ 100 g algae Results Heptane, 5:1 Solvent:Algae Ratio : τ = 3min, K = 1.70g/ 100g algae Time (min) Hexane

18 g Oil extracted/ 100 g algae Results Heptane, 30:1 Solvent:Algae Ratio : τ = 7min, K = 2.61g/ 100g algae Time (min) Hexane

19 g OIl extracted/ 100g algae Results Heptane, 30:1 Versus Hexane, 5: τ = 10min, K = 2.75g/ 100g algae τ = 7min, K = 2.61g/ 100g algae Hexane, 5:1 Heptane, 30: Time (min) Hexane

20 Results Comparison of Kinetics Model Constants Time Constant τ, min Maximum Extractable Oil, K, g/100 g algae Hexane Hexane 5:1 30:1 Heptane Heptane 5:1 30: Hexane

21 Conclusions Hexane and Heptane extract very similar material

22 Conclusions Heptane extracts oil faster, but not as much oil can be obtained per gram algae Hexane Extraction is slower but higher yields can be obtained

23 Conclusions To get similar results, you need 6x as much Heptane

24 Future Work More Heptane runs at 5:1 ratio. Test Other Solvent:Algae ratio (R) to develop the Kinetics parameters: K = f(r) and τ = f(r) Use the Kinetics parameters K and τ to optimize the oil extraction process.

25 Acknowledgement Dr. Ihab Farag Nancy Whitehouse Jon Newell Seth Tremblay

26 Question?