Post on 09-Sep-2019
Photobioreactor Design & Algae Biodiesel Production Teaching Module
Anthony Butterfield Assistant Professor, Department of Chemical Engineering
University of Utah
AIChE Annual Meeting San Francisco, November 6, 2013
Chemical Engineering Concepts
• Introductory teaching module for:
–Biochemical engineering.
– Streamlines, settling fluid dynamics.
–Basic organic chemistry.
–Combustion.
–Analytical methods.
Module Use
• Introductory Freshman Design Laboratory. – Thursday, 2:38PM, Union Square 25.
• Senior Unit Ops.
• Outreach. – Summer Camp.
• K-12 Education. – High school engineering courses.
Module Introduction for Students Start With a Problem
Author: Association for the Study of Peak Oil
Environmental Costs
CO2, NOx, SOx, particulates…
Current State
"BP Statistical review of world energy June 2006" (XLS). British Petroleum. June 2006. Retrieved 2007-04-03.
Photobioreactor Design Competition
• Our lab is conducting research on catalysts which may convert algae oil into diesel fuel. However, we are constantly in need of more oil for experimentation.
• The University of Utah would like you to design a bench top photobioreactor with the goal of growing algae as quickly as possible.
Photobioreactor Design Competition
• Batch process.
• Max footprint: ½ m by ½ m. Max height: ¾ m.
• Stirred by air lift mixing.
• Maximize algae growth rate.
– Use optical density.
• Replace evaporated water.
Materials
• Provided:
– Aquarium Tubing.
– Sparger, Air stones.
– Air line (soaker hose, from Home Depot).
– Fluorescent Lights.
– Algae and media.
• All at the same starting concentrations.
– Compressed air.
• BYORV (Bring your own reaction vessel).
Algae (Cyanobacteria) Species
Synechococcus Elongatus Strain isolated by Lance Seefeldt
(Utah State University) from the Great Salk Lake
http://www.fishersci.com/ecomm/servlet/fsproductdetail_10652_164875
38__-1_0
Gloeocapsa
Maintaining Cultures Cheaply
BG-11 Media Formula Taken from the Seefeldt Lab at Utah State University
Constituent mass (mg)
mass (gm)
per liter per liter
DI Water [mL] 987
100X BG-11 [mL] 10 10
Ammonium Iron (III) Citrate [mL] 1 1
Sodium carbonate [mL] 1 1
Potassium phosphate dibasic [mL] 1 1
BG-11 Micronutrients:
Constituent mass (mg)
mass (gm)
per liter per liter
DI Water [mL] 1000 1000
H3BO3 2.86 0.00286
MnCl2·4H2O 1.81 0.00181
ZnSO4·7H2O 0.222 0.000222
CuSO4·5H2O 0.079 0.000079
Co(NO3)2 0.0494 4.94E-05
100X BG-11 Media:
Constituent mass (mg)
mass (gm)
per liter per liter
DI Water [mL] 900
Sodium Nitrate 149600 149.6
Magnesium Sulfate heptahydrate 7490 7.49
Calcium chloride dihydrate 3600 3.6
Citric Acid 600 0.6
Sodium EDTA 104 0.104
Trace element solution [mL] 100 100
1000X Ammonium iron (III) citrate:
Constituent mass (mg)
mass (gm)
per liter per liter
DI Water [mL] 1000
Ferric ammonium citrate 6000 6
1000X Sodium carbonate:
Constituent mass (mg)
mass (gm)
per liter per liter
DI Water [mL] 1000
Sodium carbonate 20000 20
1000X Potassium phosphate dibasic:
Constituent mass (mg)
mass (gm)
per liter per liter
DI Water [mL] 1000
Potassium phosphate dibasic 30500 30.5
Simplified Media Formula
400mg/L
Miracle-Gro
Photobioreactors
Air Lift Mixing
• Use of buoyant gas to mix liquid.
• Bubbles drag fluid along with them.
Growth Data Collection
• You could use a commercial spectrophotometer…
• We have each student build and test a spectrophotometer early in their freshman design course.
Butterfield, Young, An Effective and Economical Photometer, Chemical Engineering Education , Vol 46 (3), pp. 152-156, 2012
The Math of Simple Microbial Growth
New Total = Old Total + New Cells
Exponential Growth
Phases of Cellular Growth
What’s Missing?
• Cells eat…
• Cells excrete waste…
• Cells die…
0
0.2
0.4
0.6
0.8
1
1.2
0 50 100 150 200 250 300 350 400
Absorbance y = 0.0058x - 0.0139
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
0 50 100 150 200
Absorbance vs time (hrs)
Absorbance
Linear (Absorbance)
Biodiesel Component
• Optimal to let cells to grow at least one week.
– What to do?...
• During growth students are tasked:
– Each team selects and analyzes a competing biologically derived oil.
• Corn, canola, olive, peanut, coconut, vegetable…
• Create biodiesel from your oil.
• Analyze your fuel and compare each.
Hydrophobic
Hydrophilic
Transesterification
• Breaking one triglyceride into glycerol and three molecules of fuel.
Biodiesel Process
3. Mix Solution 1 into 2. • Stir vigorously for 30 min. • Temperature should be kept
between 55 °C and 65 °C. • You CANNOT exceed 70 °C.
NaOH & Methanol are very dangerous. Use safety glasses, gloves, and the fume hoods.
1. Make Solution 1: • 10 ml of methanol. • In a 15 ml disposable
centrifuge tube. • Dissolve in 0.17 g to
0.22 g of NaOH.
2. Make Solution 2: • 40 ml oil (vegetable,
canola, olive….) • In a 125 ml Erlenmeyer
flask • Heated to 60 °C.
Be vary careful when weighing
out NaOH to avoid spills.
Clean up.
Biodiesel Process
4. Centrifuge in a 50 ml disposable centrifuge tube. – 5 min @ 4,000 rpm.
– BALANCE! • Get a Prof or TA to start.
5. Separate. – Remove bottom hydrophilic glycerol phase with a
disposable pipette; place in 15 ml centrifuge tube.
6. Clean up, & test product properties… next week.
Biodiesel Analysis
• Density. • Relative Viscosity.
– Flow through an orifice.
• Refractive Index. • UV-Vis. • FTIR. • Flame Temperature.
– IR Camera
• Flame Properties. – Sooting. – Burn rate.
Associated Homework
• Team Memo.
– Materials needed and material costs to process 1,000 gal/day algae oil.
• Team Report.
– Compare all biodiesels.
• Which is our strongest competition?
• What analytical method can we use to tell between diesel and biodiesel and the starting oil. Track reaction, and test competitor's product purity?
• How can we track contaminants (glycerol)?
The Sum Total of Algae Oil
From All Reactors…
Use in Summer Camps
Use in High School Engineering Courses
Student Self-Assessment
More Info
• Teaching Module Database:
– http://www.che.utah.edu/outreach/module?p_id=19
– http://www.che.utah.edu/outreach/module?p_id=12
Questions
Photobioreactor Design & Algae Biodiesel Production Teaching Module
• Module purpose.
• Procedure.
– Photobioreactors.
– Biodiesel.
• Results.
Oil Consumption
Source: Energy Information Administration
What Do Algae Need?
• Water.
• Light. – Suspension in solution?
• Air. – CO2.
– What about O2?
• Trace minerals… – Cu, Fe, K, Co, Mn, Zn.
• What do algae need to avoid?
Module Schedule
• Conducted with one 3 hr lab per week.
– Could collect sufficient results over three days.
Week In-Class Activity Homework
1 Design and build
photobioreactors. Design Illustration & Memo
2 Finish build and start
photobioreactors. Pick oil, and produce biodiesel.
Memo on scaling up biodiesel process to 1,000 gal/day algae oil
3 Analyze and compare biodiesels. Report on biodiesel competition
4 Stop reactors and compare
performance. Report on photobioreactor
performance.