The document describes a student project to design an algae oil extraction process for biodiesel production using SuperPro simulation software. Key aspects of the design include growing photoautotrophic microalgae in a bioreactor, extracting the natural oils from the algae using centrifugation and degumming, and using the oils to produce biodiesel. The students analyzed constraints, reviewed literature on algae growth and oil content, developed unit operation models in SuperPro, and evaluated the economic viability and sustainability of their proposed design.

1. Algae Oil Extraction for
Biodiesel
By: Marguerite Azzara, Matthew Lawrence, & Rachel Burger
BE 4381
Spring 2021 Project

2. Introduction
● Fossil fuels can no longer be exploited; there is a worldwide economic,
environmental, and sustainable need for more reliable fuels.
● Biodiesel is a clean alternative fuel source produced from renewable
resources, such as vegetable oils, animal fats, and recycled cooking oils.
● Microalgae are able to grow fast and inexpensively in order to produce
natural oils that can be used to make biodiesel.

3. Goals of the Project
● Bioprocessing (biological) Goal
○ Grow photoautotrophic microalgae
○ Extract the natural oils from the microalgae
○ Eventually this oil would be used for biodiesel, but we only modeled the oil extraction
● Structural goal
○ Create a system design in SuperPro that could realistically be used in real world
applications
● Mechanical goal
○ Use bioreactor for algae growth
○ Use centrifugation, clarification, and degumming to extract and purify the algal oil
○ Potentially use waste water as algae growth medium
https://mava-foundation.org/new-material-award-2018-for-
algae-lab-luma/

4. Constraints/ Considerations
● Skills
○ Our knowledge of SuperPro
○ How to model algae growth and oil extraction processes
○ Our knowledge of kinetics
● Logistics
○ Type of microalgae
○ Size of bioreactor and subsequent unit operations
○ Batch or continuous mode
○ Cost of design process
● Time
○ Time of algae growth
○ Time allowed for the project was 1 month, give or take
○ How long the whole design process would take in the real world

5. Constraints/ Considerations
● Safety
○ Safe working environment
○ Handling chemicals (hexane) and waste products correctly, also disposing of them correctly
● Ethical
○ Proper waste disposal
○ Making algal biofuel is more ethical than using fossil fuels since fossil fuels are nonrenewable
and have a large carbon footprint.
● Ecological
○ Some waste products can be recycled back into the bioreactor or gathered and sold for other
purposes
○ The algae growing in the raceway pond can also be used to capture CO2 to reduce carbon
emissions
○ Waste water could be potentially used as algae growth medium, depending on the nutrients in
the waste water.
● Ultimate use
○ The oils from the algae will be used to make biodiesel, which is a cleaner alternative to
petroleum based oils used for vehicles.

6. Literature Review
● Microalgae are tiny, unicellular algae that normally grow in suspension
within a body of water, like an algae pond.
● Microalgae are being considered as sources for biofuel production
because of their relatively high oil content and rapid biomass growth.
● The main natural oil made by microalgae is triglycerol, which is the right
kind of oil for biodiesel.
● Most algal biofuel production relies on photoautotrophic algae growth,
which uses sunlight as a free source of energy.
http://sphinx.murdoch.edu.au/units/extern/BIO301/teach/student%20websites%20
2010/30675968%20Biofuels%20from%20Algae/Summary%202.htm

7. Past Experiences- Biodiesel Lab
● In the biodiesel lab earlier this semester, we used different cooking oils to
convert into biodiesel. This was done to test which cooking oil would
produce the largest biodiesel yield.
● This lab covers what would be done to the algal oil after it was extracted
from the algae. Our design process covers the whole extraction process
before converting the oil into biodiesel.
● However, we learned that algal oil contains greater promise with a recent
study showing that only 0.3% of the total land in the US may be cultivated
for algal oils providing enough energy to displace all transportation fuels
currently in the US.

8. Potential Design Options/ Unit Operations
● Pretreatment: transporting a starting culture of algae and growth medium
into the bioreactor vessel
● Reaction: use of bioreactor to grow the algae
○ 174 CO2 + 2.5 (NH4)2HPO4 +44 NO3
- + 6 SO4
2- + 58 H2O → 100 C1.8O0.5N0.2 + 179 O2 + 5.5
NaCl
● Biorefinery:
○ Centrifuge: separating the algae form the growth medium
○ Sonication/degumming: extracts the lipids/oils from the algae
○ Transesterification: separating the glycerol and the biodiesel from the lipids/oils
● Packing: packing, storing, and selling that glycerol and biodiesel

9. SuperPro Design - Algae Growth

10. SuperPro Design - Algae Harvesting

11. SuperPro Design - Hexane Extraction

12. SuperPro Design - Degumming

13. Economic Evaluation of Design
● Initial investment: $38,642,000
● Operating Cost Per Year:
$448,009,000
● Revenues Per Year: $115,576,000
● Return on Investment: -856.40%
● Initial investment: $305,344,000
● Operating Cost Per Year:
$111,793,000
● Revenues Per Year: $126,603,000
● Return on Investment: 14.41%
Our Design Professional Model Design

14. Sustainability of Design
● Algae is a sustainable and renewable resource.
● Our growth type, photoautotrophic growth, focuses on utilizing sunlight
and potentially wastewater as primary nutrient sources.
● Many solid, liquid, and gas byproducts can be recycled back into the
system or separated and sold for profit.
○ Anaerobic digestion - CO2 and Methane for power generation
○ Biomass for energy generation
○ Protein for Animal Feed

15. Conclusions
● Autotrophic growth of algae for biofuel production is a complex, cost
intensive process.
● Utilization of intermediate products is an essential part of reducing
production costs and making algae an economically viable alternative to
fossil fuels.
● The sustainability of the design can increase when “waste products” are
recycled back into the system or used in another process to generate an
necessary substrate.
● This method is a potentially sustainable alternative to fossil fuels.
Research of this process should continue to further maximize efficiency.

16. References
● Farm-Energy. “Algae for Biofuel Production.” Farm Energy, 12 Apr. 2019,
farm-energy.extension.org/algae-for-biofuel-production/.
● Walker T. & Xiao R. (2021) Beer Fermentations. Unpublished Laboratory
Notes, BE 4381, Clemson University.
● Intelligen. “Algal Oil (Algae Biofuel) SuperPro Example.” Intelligen,
SuperPro Designer, SchedulePro, EnviroPro, 3 Nov. 2020,
www.intelligen.com/download/literature/.