algae to alkanes

231 Pages·2014·2.74 MB·English

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Department of Chemical & Biomolecular
Senior Design Reports (CBE)
Engineering
4-2010
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Liane S. Carlson
University of Pennsylvania
Michael Y. Lee
University of Pennsylvania
Chukuemeka A.E. Oje
University of Pennsylvania
Arthur Xu
University of Pennsylvania
Follow this and additional works at: https://repository.upenn.edu/cbe_sdr
Part of the Chemical Engineering Commons
Carlson, Liane S.; Lee, Michael Y.; Oje, Chukuemeka A.E.; and Xu, Arthur, "ALGAE TO ALKANES" (2010).
Senior Design Reports (CBE). 12.
https://repository.upenn.edu/cbe_sdr/12
This paper is posted at ScholarlyCommons. https://repository.upenn.edu/cbe_sdr/12
For more information, please contact [email protected].
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Once considered infeasible and unviable, recently there has been renewed interest in the development of
algae-derived transportation fuels. Currently, there are no commercialized algae to fuel ventures, and
much debate is centered on the economic viability of such a process. Research conducted by NASA,
among others, has expressed skepticism that terrestrially cultivated algae can ever compete with
conventional fuels. The purpose of this project is to evaluate the economic feasibility of an algae-to-fuel
venture that incorporates the state-of-the-art technologies available in the open literature.
Our challenge is to produce 20 thousand barrels per day of n-alkane product that meets the current diesel
fuel specifications. To arrive at a recommendation, separate models were built for algae cultivation, lipid
extraction, and lipid processing at a scale necessary to reach this target.
This analysis departs from prior studies on two major fronts. First, this analysis considers OriginOil’s new
method of lipid extraction instead of conventional hexane extraction. Second, the objective of the lipid
processing module is to produce n-alkanes from triglycerides, as opposed to producing FAME biodiesel.
The n-alkane product from this process is comparable to petroleum-based diesel fuels. Thus it can be
readily incorporated into existing energy infrastructure as a diesel blending stock or as a feedstock for
other processing units in the refinery.
Our economic analysis shows that an algae-to-fuel venture is profitable if the fuel is sold at $3/gallon, the
current price of diesel. However, the commercialization of such a process is difficult due to the large total
capital investment. At $2.2 billion, the capital investment of algae cultivation is nearly 40 times that of
processing, which results in annual depreciation and fixed costs of nearly half of the revenue. Investors
would be hesitant to invest such a large amount of money in an algae cultivation process where there is
high uncertainty in the cost requirements.
Algae-to-fuel economics can be improved by realizing higher value uses of the algae biomass. Biomass
composes of over half of algae product, and their potential uses in pharmaceuticals, chemicals, and
biomass power generation far surpass their value as animal feed. Proposed carbon-cap-and-trade
programs may bring additional revenue. Thus, any algae-to-fuel venture should seek to optimize the value
of its byproducts. Governments can support algae-to-fuel ventures by offering tax credits or mandating a
market for renewable fuels, but the benefits of these measures are unclear. Additional analysis should
address the uncertainties of various costs and look to reduce capital investment.
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Chemical Engineering
This working paper is available at ScholarlyCommons: https://repository.upenn.edu/cbe_sdr/12
ALGAE TO ALKANES

Liane S. Carlson
Michael Y. Lee
Chukuemeka A.E. Oje
Arthur Xu

Department of Chemical & Biomolecular Engineering
University of Pennsylvania
Spring 2010

Faculty Advisors: Dr. Stuart W. Churchill and Dr. Warren D. Seider
Project Recommendation by: John A. Wismer, Arkema, Inc.

Professor Leonard A. Fabiano
Department of Chemical and Biomolecular Engineering
University of Pennsylvania
220 South 33rd Street
Philadelphia, PA 19104-6393

21 April 2010

Dear Mr. Fabiano, Dr. Churchill, and Dr. Seider,

This spring, our design team was presented with the task of evaluating the long term potential of
producing biofuels from algae for our client, a venture capital firm interested in alternative energy. The
project, suggested by Mr. John A. Wismer of Arkema, Inc., called for the design of an algal cultivation
process, a lipid extraction process, and a method processing the lipids into an n-alkane product suitable
for transportation fuel. To effectively evaluate the potential of an algae-to-fuel project, the economics of
each process was determined and compared to the current price of diesel, which is $3/gallon.
The algae cultivation process was modeled primarily after the SimgaeTM Algal Biomass
Production System developed by Diversified Energy Corporation and details a simple, cost effective
process. The lipid extraction stage was modeled using OriginOil, Inc.’s Single-Step ExtractionTM process.
In this process, Quantum FracturingTM, combined with pulses of electromagnetic fields, fractured the
algae cell wall to release the lipids. The triglyceride component of the lipid stream was then
transported to a petroleum refinery by rail and converted into an n-alkane product using a catalytic
hydrotreating process.
The analysis indicates that a venture combining all three modules of the supply chain would be
profitable. At an n-alkane selling price of $3/gallon and a 15% discount rate, the projected net present
value (NPV) of the project is $289,406,000. However, there is great uncertainty in various cost
requirements since the technologies are new and unproven. The total capital investment of $2.8 billion,
primarily from the algae cultivation process, poses a significant barrier that may discourage investors.
The processes design, economic analysis, and recommendations are discussed in more detail in this report.

Liane S. Carlson Michael Y. Lee

Chukuemeka A.E. Oje Arthur Xu

TABLE OF CONTENTS

I. INTRODUCTION AND PROJECT CHARTER .................................... 1

A. Abstract ................................................................................................................................... 1
B. Motivation ............................................................................................................................... 1
C. Barriers For Algae Conversion Into Fuel .................................................................................. 2
D. Project Summary: Converting Algae Into Fuel ........................................................................ 3
II. OVERALL CONCEPT STAGE ......................................................... 5

A. Overall Flowsheet .................................................................................................................... 5
B. Market And Competitive Analysis ........................................................................................... 5
C. Customer Requirements .......................................................................................................... 6
D. Transportation Between Modules And Storage ...................................................................... 7

MODULE I: ALGAE CULTIVATION ........................................................ 8

III. CONCEPT STAGE ........................................................................ 9

A. Picking An Algae Strain ............................................................................................................ 9
B. Increasing Lipid Content .......................................................................................................... 9
C. Location Screening ................................................................................................................. 10
D. Picking A Cultivation Process ................................................................................................. 12
E. Optimal Conditions For Cultivation ....................................................................................... 14
F. Proposed Module I Parameters ............................................................................................. 15
Proposed Algae, Nannochloropsis Sp................................................................................ 15
Proposed Location ............................................................................................................ 15
IV. FEASIBILITY AND DEVELOPMENT STAGES ................................. 18

A. Proposed Cultivation Process - Simgaetm .............................................................................. 18
B. General Material Balances ..................................................................................................... 20
Algae Material Balance ..................................................................................................... 20
Multiple Fields .................................................................................................................. 24
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Optimal Conditions For Nannochloropsis Sp. Cultivation ................................................. 24
Cleaning The System – Accumulation Of Biofilm .............................................................. 25
Production Comparisons ................................................................................................... 26
Co Source And Consumption ........................................................................................... 26
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Nutrient Consumption ...................................................................................................... 28
Oxygen Production ........................................................................................................... 29
C. Land Requirement ................................................................................................................. 29
D. Energy Calculations ............................................................................................................... 30
E. Economics .............................................................................................................................. 30
Capital Costs ...................................................................................................................... 30
Continuous Costs .............................................................................................................. 31
Economic Summary .......................................................................................................... 33
A Glance At Economics: Diversified Energy Algal Biofuels Modeling And Analysis .......... 34
F. Concern With The Simgaetm Analysis: Dilute Exiting Algae Stream ....................................... 36
G. Other Important Considerations ........................................................................................... 36

MODULE II: LIPID EXTRACTION ......................................................... 37

V. CONCEPT STAGE ...................................................................... 38

A. Lipid Extraction ...................................................................................................................... 38
B. Conventional Lipid Extraction ................................................................................................ 38
C. OriginOilTM Extraction Process .............................................................................................. 39
VI. FEASIBILITY AND DEVELOPMENT STAGES ................................. 40

A. Process Design and Material Balances .................................................................................. 41
B. Process Description ............................................................................................................... 43
C. Energy Balance and Utility Requirements ............................................................................. 45
D. Equipment List and Unit Descriptions ................................................................................... 47
E. Specification Sheets ............................................................................................................... 48
F. Operating Costs and Economic Analysis ................................................................................ 51

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MODULE III: LIPID PROCESSING ........................................................ 53

VII. CONCEPT STAGE ...................................................................... 54

A. Preliminary Process Synthesis ............................................................................................... 54
B. Facility Design ........................................................................................................................ 55
C. Assembly of Database............................................................................................................ 56
D. Bench-Scale Laboratory Work ............................................................................................... 57
VIII. FEASIBILITY AND DEVELOPMENT STAGES ................................. 58

A. Process Flow Diagram and Material Balances ....................................................................... 59
B. Process Description ............................................................................................................... 64
C. Energy Balance and Utility Requirements ............................................................................. 67
D. Equipment List and Unit Descriptions ................................................................................... 68
E. Specification Sheets ............................................................................................................... 75
F. Fixed-Capital Investment Summary ....................................................................................... 98
G. Other Important Considerations ......................................................................................... 100
H. Operating Costs ................................................................................................................... 101

IX. OVERALL ECONOMIC ANALYSIS .............................................. 105

Fixed-Capital Investment .......................................................................................................... 105
Variable Costs ........................................................................................................................... 106
Fixed Costs ................................................................................................................................ 107
Sensitivity Analysis .................................................................................................................... 107
Other Important Considerations .............................................................................................. 107
Carbon Credits ............................................................................................................... 107
Processing Costs .............................................................................................................. 108
Government Subsidies and Incentives ............................................................................ 109

X. CONCLUSIONS AND RECOMMENDATIONS ............................. 110

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ACKNOWLEDGEMENTS ................................................................... 111

REFERENCES ................................................................................... 112

APPENDIX ....................................................................................... 115

I. Problem Statement ................................................................ 116

II. Module I Calculations ............................................................ 119

Cost and Make Up of the Nutrients .......................................................................................... 119
Determination of Algae Composition ....................................................................................... 120
Calculation of CO Enriched Air ................................................................................................ 121
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Production Conversions ............................................................................................................ 122
III. Module II: Conventional Energy Requirements ...................... 123

IV. ASPEN PLUS Simulation ......................................................... 124

ASPEN Flowsheet of Hydrotreating Process ............................................................................. 125
ASPEN Simulation Results ......................................................................................................... 126
V. Module III: Equipment Design Calculations ............................ 148

VI. Profitability Analysis Spreadsheet .......................................... 171

VII. Material Data Safety Sheets (MSDS) ...................................... 179

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