Senior Design Final Report
The Diesel Crew
Team One
Adam Alexander, Michael Lubben,
Angus Richeson, and Thomas Voss
ENGR 340 - Senior Design Project
Calvin College
May 15, 2014
© 2014, The Diesel Crew and Calvin College
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Executive Summary
Calvin College Senior Design Team One, The Diesel Crew, designed and prototyped a reactor
system to convert waste cooking oil into biodiesel. Biodiesel has regained interest in the last decade as
an alternative to petrol diesel, due to rising fuel prices and an ever increasing push towards
sustainability. The members of the Diesel Crew have a common interest in exploration of alternative fuel
sources and participation in a hands on project. With these shared desires, the team selected a biodiesel
reactor system for this project.
The team had a few goals for this project; the team wanted to design and operate a continuous
process, implement a control system, and build a reactor that was competitive with established batch
processes in terms of size and production. The team desired to build a reactor system fit for an
institution the size of Calvin College, or for a home user. The team met these goals while addressing
safety concerns, such as chemical exposure, flammability and high temperatures. These criteria were
chosen on the values of stewardship, transparency and responsibility to the end-user, all values shared
by the team members.
This report details the system design that filters crude waste cooking oil, converts it to biodiesel,
recovers and re-cycles un-reacted reagents, and purifies the biodiesel product. The process begins in the
dewatering unit, where the oil is filtered and water is removed by evaporation. The oil is pumped into
the first reactor, a CSTR, where it is mixed with the catalyst and methanol. Partial conversion is achieved
in the CSTR and the slurry is pumped into the microwave PFR. Once the waste cooking oil is reacted, the
products must be separated and purified. The first step in the separation train is the settling tank to
remove the solid catalyst, followed by a packed distillation column. The packed column removes the
methanol and recycles it, while the biodiesel and glycerol byproduct are passed on to a holding tank.
From this tank the products are pumped into the density separation column to remove the glycerol. The
now almost pure biodiesel product passes through the packed ion exchange resin column to remove any
final impurities.
The Diesel Crew was able to successfully design and prototype a continuous system for biodiesel
production. The final system meets design goals of being small enough to fit through a doorway with
only moderate deconstruction, safe, and competitive with the KOH batch reaction. Two significant
innovations in the prototype are static mixers to achieve a slurry in a PFR and a microwave reactor to
achieve higher conversion. The team concludes that a continuous reaction system is not very feasible for
a small institution or home biodiesel producer. Due to the large number of difficult operations and
higher safety concerns with operating a continuous process, the team believes that a batch process is
more viable for the home user.
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Table of Contents
EXECUTIVE SUMMARY ..................................................................................................................... III
TABLE OF CONTENTS TABLE OF FIGURES ........................................................................................... IV
TABLE OF FIGURES ........................................................................................................................... VI
TABLE OF TABLES ........................................................................................................................... VIII
SUMMARY OF IMPORTANT ABBREVIATIONS IN DOCUMENT ............................................................. IX
1 INTRODUCTION ............................................................................................................................1
1.1 PROBLEM STATEMENT ....................................................................................................................1
1.2 OBJECTIVES ..................................................................................................................................1
1.3 SCOPE .........................................................................................................................................1
1.4 BACKGROUND...............................................................................................................................2
1.5 POTENTIAL CUSTOMERS ..................................................................................................................3
2 DESIGN CONSIDERATIONS ............................................................................................................4
2.1 INTERFACE REQUIREMENTS ..............................................................................................................4
2.2 FUNCTIONAL REQUIREMENTS ...........................................................................................................4
2.3 PERFORMANCE REQUIREMENTS ........................................................................................................4
2.4 ENVIRONMENTAL REQUIREMENTS .....................................................................................................4
3 CHEMISTRY OVERVIEW AND EXPERIMENTAL RESULTS...................................................................6
4 PHYSICAL SYSTEM DESIGN ............................................................................................................9
4.1 SYSTEM HOUSING ........................................................................................................................ 10
4.2 CONTROL SYSTEM ........................................................................................................................ 11
4.2.1 REQUIREMENTS................................................................................................................................... 11
4.2.2 PROGRAMMABLE LOGIC CONTROLLER..................................................................................................... 11
4.2.3 USER INTERFACE ................................................................................................................................. 13
4.2.4 NATIONAL INSTRUMENT I/O FIELDPOINT MODULES ................................................................................. 13
4.2.5 CONTROL LOOP FEEDBACK DESIGN......................................................................................................... 14
4.2.6 ELECTRO-MECHANICAL COMPONENTS .................................................................................................... 16
4.2.7 SAFETY IMPLEMENTATIONS ................................................................................................................... 16
4.3 MATERIAL STORAGE ..................................................................................................................... 16
4.4 TUBING ..................................................................................................................................... 16
4.5 PUMPS...................................................................................................................................... 17
4.6 COARSE FILTER ............................................................................................................................ 18
4.7 DEWATERING.............................................................................................................................. 19
4.8 FINE FILTER ................................................................................................................................ 20
4.9 CATALYST .................................................................................................................................. 20
4.10 REACTOR ................................................................................................................................. 21
4.10.1 MICROWAVE PFR ............................................................................................................................. 22
4.10.2 CSTR .............................................................................................................................................. 22
4.11 CATALYST RECOVERY .................................................................................................................. 23
4.12 METHANOL RECOVERY ................................................................................................................ 24
4.13 GLYCEROL SEPARATOR ................................................................................................................ 25
4.14 POLISHING COLUMN ................................................................................................................... 26
5 SUGGESTIONS FOR DESIGN IMPROVEMENT ................................................................................ 28
5.1 CONTINUOUS SETTLING TANK OPERATION ......................................................................................... 28
5.2 CONTINUOUS CATALYST FEED SYSTEM .............................................................................................. 28
5.3 IMPROVED MICROWAVE OPERATION ............................................................................................... 29
5.4 IMPROVED HEAT CAPTURE ............................................................................................................. 29
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5.5 IMPROVEMENTS TO CONTROL SYSTEM .............................................................................................. 29
6 BUDGET ..................................................................................................................................... 30
7 SAFETY CONCERNS ..................................................................................................................... 31
8 ENVIRONMENTAL CONSIDERATIONS........................................................................................... 33
9 TEAM MEMBER RESPONSIBILITIES .............................................................................................. 34
9.1 ADAM ALEXANDER ...................................................................................................................... 34
9.2 MICHAEL LUBBEN ........................................................................................................................ 34
9.3 ANGUS RICHESON ........................................................................................................................ 34
9.4 THOMAS VOSS ............................................................................................................................ 34
10 CONCLUSION ............................................................................................................................ 35
11 ACKNOWLEDGEMENTS ............................................................................................................. 36
12 REFERENCES ............................................................................................................................. 38
APPENDICES ...................................................................................................................................... I
Appendix A. Reaction Research Summary .................................................................................................. I
Appendix B. Calcium Oxide Catalyst Details ............................................................................................. III
Appendix C. Solubility Testing................................................................................................................... IV
Appendix D. HPLC Summary ...................................................................................................................... V
Appendix E. LabVIEW Block Diagram ...................................................................................................... XIV
Appendix F. Expenses and Donations ..................................................................................................... XVI
Appendix G. Experimental Summaries ................................................................................................. XVIII
Appendix H. ASTM Specifications for B-100 ......................................................................................... XXXI
Appendix I. Redesign of Subsystems ................................................................................................... XXXII
Appendix J. 3-D Printed Parts .............................................................................................................XXXIV
Appendix K. Schematic Drawings.......................................................................................................XXXVII
Appendix L. Calculations ......................................................................................................................... XLI
Appendix M. Pictures of System .......................................................................................................... XLVII
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Table of Figures
FIGURE 1-1 CONVERSION OF BIOLOGICAL OILS TO BIODIESEL. .....................................................................................................2
FIGURE 1-2 REVERSIBLE REACTION OF FAME TO FFA. ..............................................................................................................3
FIGURE 1-3 SOAP MAKING PROCESS (ALSO KNOWN AS SAPONIFICATION)......................................................................................3
FIGURE 3-1* BATCH REACTION RESULTS FOR VARYING CATALYST RATIO ......................................................................................7
FIGURE 3-2 BATCH REACTION RESULTS FOR VARYING VOLUME RATIO..........................................................................................7
FIGURE 4-1 PROCESS OVERVIEW OF REACTION SYSTEM .............................................................................................................9
FIGURE 4-2 REACTOR SYSTEM PRE-BUILT FRAME ...................................................................................................................11
FIGURE 4-3: LABVIEW FRONT PANEL PROCESS FLOW DIAGRAM USER INTERFACE .......................................................................12
FIGURE 4-4: NATIONAL INSTRUMENTS FIELDPOINT MODULES AND POWER SUPPLIES....................................................................13
FIGURE 4-5: BLOCK DIAGRAM OF MICROWAVE PID CONTROLLER IN LABVIEW VI .......................................................................15
FIGURE 4-6: FRONT PANEL MICROWAVE PFR PID CONTROLLER INTERFACE IN LABVIEW VI .........................................................15
FIGURE 4-7 FILTER MESH FOR DEWATERING SYSTEM .............................................................................................................18
FIGURE 4-8 DESIGN OF DEWATERING SYSTEM .......................................................................................................................20
FIGURE 4-9 SETTLING TANK SEEN FROM FEED SIDE OF TANK ....................................................................................................24
FIGURE 4-10 BOTTOM CAP TO POLISHING COLUMN WITH WIRE MESH INSERTED ........................................................................27
FIGURE 5-1 TRICKLER PROTOTYPE TESTING. ..........................................................................................................................28
FIGURE 7-1 NFR SAFETY LABELS .........................................................................................................................................31
FIGURE 7-2 HMIS LABELS .................................................................................................................................................31
FIGURE C-1 CALIBRATION CURVE FOR 3/27 TEST USING A GLASS VIAL ...................................................................................... IV
FIGURE C-2 CALIBRATION CURVE FOR 3/27 TEST USING PLASTIC VIAL ....................................................................................... IV
FIGURE D-1 EXAMPLE OF HPLC RETENTION PEAKS ............................................................................................................... VII
FIGURE D-2 CALIBRATION CURVE FOR MONOOLEIN AT FOR HPLC METHOD ............................................................................. VIII
FIGURE D-3 CALIBRATION CURVE FOR OLEIC ACID AT FOR HPLC METHOD ..................................................................................IX
FIGURE D-4 CALIBRATION CURVE FOR LINOLEIC ACID AT FOR HPLC METHOD ..............................................................................IX
FIGURE D-5 CALIBRATION CURVE FOR METHYL LINOLATE AT FOR HPLC METHOD .........................................................................X
FIGURE D-6 CALIBRATION CURVE FOR METHYL OLEATE AT FOR HPLC METHOD ............................................................................X
FIGURE D-7 CALIBRATION CURVE FOR METHYL LINOLENATE AT FOR HPLC METHOD .....................................................................XI
FIGURE D-8 SPECTRA FOR BATCH EXPERIMENT B, CONVERSION OF 7.7% ...................................................................................XII
FIGURE D-9 SPECTRA OF BATCH EXPERIMENT F, CONVERSION OF 72.7% ..................................................................................XIII
FIGURE E-1 PART 1 OF LABVIEW BLOCK DIAGRAM ............................................................................................................. XIV
FIGURE E-2 PART 2 OF LABVIEW BLOCK DIAGRAM .............................................................................................................. XV
FIGURE G-1 BATCH REACTION SETUP ................................................................................................................................. XX
FIGURE G-2 MICROWAVE BATCH SETUP ........................................................................................................................... XXII
FIGURE G-3 MICROWAVE NODE DETECTION (LOW) ........................................................................................................... XXIII
FIGURE G-4 MICROWAVE NODE DETECTION (MIDDLE) ...................................................................................................... XXIV
FIGURE G-5 MICROWAVE NODE DETECTION (HIGHER) ........................................................................................................ XXV
FIGURE G-6 DISSOLVED PRODUCT IN THF WITH PH INDICATOR ............................................................................................ XXVI
FIGURE G-7 DISSOLVED PRODUCT IN THF AT EQUIVALENCY POINT, PALE SALMON COLOR ......................................................... XXVII
FIGURE G-8 DISSOLVED PRODUCT IN THF AFTER EQUIVALENCY POINT, PINK SALMON COLOR ..................................................... XXVII
FIGURE G-9 SETTLED CATALYST DISTRIBUTION (20°C)......................................................................................................... XXX
FIGURE I-1 INITIAL DEWATERING SYSTEM DESIGN ............................................................................................................ XXXII
FIGURE I-2 BURNED OUT HEATING ELEMENT FROM INITIAL DEWATERING DESIGN ................................................................. XXXIII
FIGURE J-1 CAD .IDW FILE OF SPRAYER NOZZLE .............................................................................................................. XXXIV
FIGURE J-2 MEOH COLUMN DISTRIBUTER ...................................................................................................................... XXXV
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FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
J-3 FPT FITTING FOR BOTTOM CAP OF THE POLISHING COLUMN .............................................................................. XXXVI
J-4 MPT FITTING FOR BOTTOM CAP OF POLISHING COLUMN .................................................................................. XXXVI
K-1 SCHEMATIC OF DEWATERING SYSTEM .......................................................................................................... XXXVII
K-2 MEOH RECOVER SCHEMATIC .................................................................................................................... XXXVIII
K-3 SCHEMATIC OF COLUMN TRAIN TO CLEAN BIODIESEL ....................................................................................... XXXIX
K-4 DIAGRAM OF STATIC MIXERS USED IN MICROWAVE PFR ........................................................................................ XL
M-1 TOP VIEW OF BAFFLE DESIGN IN CSTR ..........................................................................................................XLVII
M-2 MEOH RECOVERY UNIT .............................................................................................................................XLVIII
M-3 DENSITY SEPARATION COLUMN ..................................................................................................................... XLIX
M-4 EMPTY RESIN COLUMN ..................................................................................................................................... L
M-5 OVERVIEW OF PHYSICAL MODULES AND CONNECTIONS OF CONTROL SYSTEM............................................................ LI
M-6 COMPLETED PROTOTYPE ................................................................................................................................. LII
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Table of Tables
TABLE 2-1 SELECTED BIODIESEL PRODUCT SPECIFICATIONS .........................................................................................................4
TABLE 4-1 KEY COMPONENT PROPERTIES (AT ROOM TEMPERATURE) .........................................................................................10
TABLE 4-2: SOLID STATE RELAY OUTLINE ..............................................................................................................................16
TABLE 4-3: TUBING DECISION MATRIX .................................................................................................................................17
TABLE 4-4: BIODIESEL REACTOR PUMP REQUIREMENTS...........................................................................................................17
TABLE 4-5 DESIGN DECISION MATRIX FOR CATALYST CHOICE ...................................................................................................21
TABLE A-1 INTENSIFIED REACTOR SUMMARY (MAZUBERT, POUX AND AUBIN) ................................................................................I
TABLE D-1 SUMMARY OF SOYBEAN OIL COMPOSITION ............................................................................................................. V
TABLE D-2 SUMMARY OF COMPOUNDS IN FATTY ACID METHYL ESTER MIX................................................................................ VI
TABLE D-3 SUMMARY OF POMONA GROUP GRADIENT ELUTION............................................................................................... VI
TABLE D-4 SUMMARY OF RETENTION TIMES FOR STANDARDS ................................................................................................. VII
TABLE D-5 SUMMARY OF HPLC CALIBRATION DATA ...............................................................................................................XI
TABLE D-6 SUMMARY OF STATISTICAL ANALYSIS OF CALIBRATION CURVES .................................................................................XII
TABLE F-1 ITEMIZED EXPENDITURES OF TEAMS 1 ................................................................................................................. XVI
TABLE F-2 ITEMIZED DONATIONS AND BORROWED EQUIPMENT VALUE .................................................................................. XVII
TABLE G-1 RESULTS OF FINE FILTER TEMPERATURE EXPERIMENT ........................................................................................... XVIII
TABLE G-2 SUMMARY OF RESULTS FROM ACRYLIC TESTING ................................................................................................... XIX
TABLE G-3 BATCH REACTION TESTING RESULTS................................................................................................................... XXI
TABLE G-4 SUMMARY OF ACID NUMBER RESULTS OF VARIOUS EXPERIMENTAL PRODUCTS ...................................................... XXVIII
TABLE G-5 SUMMARY OF RESULTS OF ACID NUMBER TEST AFTER POLISHING SAMPLES........................................................... XXVIII
TABLE G-6 SUMMARY OF PHASE REGION TEST RESULTS...................................................................................................... XXIX
TABLE H-1 ASTM SPECIFICATIONS FOR B-100 .................................................................................................................. XXXI
TABLE L-1 SUMMARY OF PROPERTIES OF COMPONENTS OF PFR STREAM ................................................................................ XLIII
TABLE L-2 IDEAL LIQUID REACTOR EFFLUENT ..................................................................................................................... XLIII
TABLE L-3 SUMMARY OF PFR STREAM FLOW RATES ...........................................................................................................XLIV
TABLE L-4 SUMMARY OF POWER REQUIREMENTS, ENERGY INPUT:EMBODIED ENERGY ..............................................................XLVI
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Summary of Important Abbreviations in Document
American Society for Testing and Materials .............................................................................. ASTM
20 vol% Biodiesel Blend ............................................................................................................. B-20
Pure Biodiesel............................................................................................................................. B-100
Fatty Acid Methyl Ester .............................................................................................................. FAME
Free Fatty Acid ........................................................................................................................... FFA
Continuous Stirred Reactor ........................................................................................................ CSTR
High Density Polyethylene ......................................................................................................... HDPE
High Pressure Liquid Chromatography ...................................................................................... HPLC
Methanol .................................................................................................................................... MeOH
Material Safety Data Sheets ....................................................................................................... MSDS
Occupational Safety and Health Admin. .................................................................................... OSHA
Packed Bed Reactor ................................................................................................................... PBR
Plug Flow Reactor....................................................................................................................... PFR
Process Flow Diagram ................................................................................................................ PFD
Ultra Violet Visible Spectroscopy ............................................................................................ UV-VIS
Work Breakdown Structure .................................................................................................... WBS
Waste Cooking Oil ...................................................................................................................... WCO
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1
Introduction
1.1 Problem Statement
As the global demand for energy proliferates, especially as developing countries increase their use
of technology, the need for improved and more sustainable energy resources increases. A large area of
concern in sustainable energy is the transportation industry. Traditionally the energy resource for
transportation has been petroleum based; however, petroleum is a not renewable over a reasonable
time frame, and at some point in the future, petroleum may not be accessible in quantities to support
the earth’s needs. A possible solution is to use a fuel that is renewable, such as biodiesel, a fuel so
named because it can be harvested in a variety of ways from plants and animal fat. A particular
attractive method is the conversion of waste cooking oil (WCO) to a usable biodiesel, as this not only
reduces waste, but produces something that can be used. The Diesel Crew developed a system to
perform this conversion for a home user or small institution that produces WCO, such as Calvin College.
1.2 Objectives
The primary objective of this group was to design a quality alternative reactor to the commonly
used batch-reactor-liquid-catalyst system. The team sought to build a prototype continuous flow reactor
to convert WCO into a usable biodiesel fuel that meets the standards and qualities of ASTM for biodiesel
fuel, a necessity for the commercial sale of the fuel. Originally, the team wanted to create a polished
prototype that would be easily operable by a person of a non-technical background, but the team
quickly realized this would take a budget and knowledge of control systems beyond what the team had.
The team sought to design a prototype for a continuous system for biodiesel production that would be
feasible for a home user or institution similar to Calvin College.
1.3 Scope
This group placed several limitations on this project. The team used a calcium oxide (CaO) catalyst
which can be recycled, but the team left the catalyst recycling outside of the scope of this project, due
to the already large nature of the project. Team one decided to use the WCO from Calvin College’s
dining services (which is soybean oil) as a typical feed to the process, though different institutions may
produce slightly different WCO. The goal for the system was to be able produce biodiesel at ASTM
standard, but the team left full ASTM biodiesel testing out of scope due to the expenses and time
associated with full testing. For design consideration, Team One defined a quality process as one that is
safe, quick, small, inexpensive, and easily operable. A faster process results in a smaller size, which helps
keep the system small enough to be transported to a variety of locations and not take up excess space.
Also, due to the complexity in design of the individual systems and the intricacy of the control systems, a
few sub units were investigated but left out of prototype integration. These systems were the catalyst
feed system and automatic catalyst removal. For this reason, while running the reactor a person is
required to feed the catalyst into the reactor. The team does have design ideas for these two systems
that were not implemented (section 5).
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1.4 Background
Raw cooking oils should not be used directly as fuel in most engines as the higher viscosity of these
oils results in carbon buildup and thus reduced engine life (US Department of Energy). Therefore, further
processing is needed. The team chose to produce the popular product of cooking oil and methanol, fatty
acid methyl esters, abbreviated FAME.
FAME, commonly called biodiesel, is typically used in a blend with traditional petroleum diesel.
Biodiesel is made by converting oils or fats, which are triglycerides, and an alcohol (usually methanol) to
fatty acid esters in a process known as transesterification (Figure 1-1). Ideally, this is done in a single
step with feedstock oil that consists only of triglycerides. However, in practice, waste oils also contain
water and free fatty acids (FFA), carbon chains not bound to a glycerol backbone. The presence of water
and FFA is problematic as one of the preferred methods of enacting transesterification is by using a basic
(alkali) catalyst such as sodium hydroxide (NaOH), which forms soap when added to FFA (Figure 1-3)
(Suwannakarn). While substantial water in the final biodiesel product is not acceptable by itself, a large
fraction of water also exacerbates the FFA to soap problem, converting biodiesel to FFAs (Figure 1-2)
(Rinnova). Besides using oils that could be converted to biodiesel, impeding process flow, and
deactivating heterogeneous catalysts, soap is also an emulsifier, making it more difficult to separate
whatever water is present from the produced biodiesel, further reducing yield.
Figure 1-1 Conversion of Biological Oils to Biodiesel.
Note: This reaction is usually done with a catalyst and a large amount of methanol to increase the rate and equilibrium
conversion towards biodiesel.
A common method to address these issues of water, fatty acid content, and soap formation is via a
two-step batch reaction process. This process utilizes an acid catalyzed pretreatment to esterify FFA,
removing methanol via vacuum before proceeding with a base-catalyzed transesterification using
potassium hydroxide. The acid pre-treatment is simply the reaction shown in Figure 1-2 driven in reverse
(from right to left).
2
Figure 1-2 Reversible reaction of FAME to FFA.
Note: This also illustrates another benefit of having an excess of methanol, since existing FFAs will be better driven to
biodiesel.
Figure 1-3 Soap Making Process (also known as saponification)
The reaction step is typically followed by vacuum vaporization of the excess methanol and using a
water wash to remove any remaining FFA, glycerol, or soap that might have been dissolved in the
biodiesel (the water is then also drained from the reactor).
The design of the Diesel Crew differed significantly in the type of reaction used. The team
eliminated the two part reaction and water wash by using a solid catalyst, CaO. By eliminating the
washing step and the liquid catalyst, the diesel crew was also able to make their system a continuous
process. The steps after the reactor are very similar for both processes except that the continuous
process includes a step to remove the catalyst. The final steps include the evaporation of methanol,
separation of glycerol and final polishing of the fuel.
1.5 Potential Customers
Any institution that produces WCO from their dining services that also has a moderate need for
diesel fuel for transportation or lawn maintenance is a potential customer. Persons who make biodiesel
at home as a hobby would also be potential customers for this type of system. The team will tailor the
design to meet the needs of a home biodiesel producer or smaller institution such as Calvin College,
which produces about 2000 pounds of WCO per month. Currently Calvin operates a shuttle van on
biodiesel as well as a few lawnmowers. A reactor of this nature would help cut costs of purchasing fuel
for this machinery.
A reactor of this type would also be useful to a larger chemical recycler that takes in WCO.
Currently, many companies collect WCO and convert it to FAME in large batch processes with
homogenous catalyst. One such company, collects and converts Calvin College’s WCO to FAME. A
company such as this would benefit from a continuous process due to the lower amount of labor
required for operation and less separation time.
For an institution to implement our reactor system, the design must meet a few requirements. First
and foremost it must be completely safe to operate, not putting the operator or anyone else in danger.
Detailed safety concerns and requirements can be found later in the report (section 7 Safety Concerns).
It is also desirable to have very little user interaction with the system and have the system be easily
operable by a person of a non-technical background, but the team did not stress this in prototype
construction and design due to limited control systems experience.
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2
Design Considerations
2.1 Interface Requirements
The ease of user interaction is of high value to the design; the ability to operate the reactor without
extensive technical knowledge will allow the system to be feasible for a home brewer or institution
similar to Calvin College. The prototype must be able to maintain steady-state with little user input. This
is accomplished through a control system that regulates system conditions, such as temperatures,
pressures and flow rates.
2.2 Functional Requirements
The functional requirements for the prototype is that it produces FAME using MeOH and WCO as
feedstock. The prototype needed to be able to hold all of the feedstock, products, and waste products.
Any necessary measurements by a user needed to be done by the prototype, not additional tooling.
Lastly, the prototype needed relative ease of mobility, i.e. should fit through a standard door frame.
2.3 Performance Requirements
A goal of the prototype is for the product to meet the ASTM standards for biodiesel (National
Biodiesel Board, 2007). A glyceride content specification was determined from the European Standard
(European Committee for Standardization, 2004). To achieve a product below the maximum glyceride
content without a separation of unreacted glycerides from FAME, a 96.5% conversion must be achieved.
Key requirements are detailed in Table 2-1 below.
Table 2-1 Selected Biodiesel Product Specifications
Property
Limit
Units
Glycerol (Total)
0.24 max
% Mass
Free Glycerol
0.02 max
% Mass
MeOH
0.2 max
% Volume
Magnesium and Calcium (combined)
5 max
PPM
Sodium and Potassium (combined)
5 max
PPM
Water and Sediment
0.05 max
% Volume
Monoglycerides
0.8 max
% Mass
Diglycerides
0.2 max
% Mass
Triglycerides
0.2 max
% Mass
* Full ASTM specifications for biodiesel can be viewed in G-2.
Due to the limitations on the scope, full ASTM testing was not done on the fuel product. Instead the
requirement was to have a high degree of separation with catalyst, glycerol and unconverted WCO.
2.4 Environmental Requirements
Feedstock will be low in sulfur content, so SO2 is not a concern as an emission from the
combusted product. The glycerol by-product is environmentally safe, and is typically discarded with
wastewater. However, if there is a significant amount of FAME or methanol in the glycerol product, the
glycerol product will have to be treated as chemical waste. The team would recommend users give
4
glycerol to a recycling facility or consult their local waste-water treatment plant. The other
environmental requirements are more specific to the area where the prototype will be operated. The
storage tanks and most of the system will be sealed to prevent fumes, especially for MeOH which is very
volatile and fairly hazardous to human health.
5
3
Chemistry Overview and Experimental Results
The reaction to produce biodiesel from WCO and methanol is nearly endothermic and reversible. A
catalyst is necessary to promote the forward reaction towards biodiesel and to reduce the reaction time
and energy input required to reach sufficient conversion. A catalyst is also required in most cases
because methanol and WCO do not mix at standard reaction temperatures and pressures; catalyst-free
methods such as the McGyan Process do exist, but they require supercritical methanol and are thus
impractical or unsafe for small scale, amateur operators to use. Therefore, the catalyst acts as an
intermediate to promote mixing and increase the reaction rate. Many different catalysts can be used in
this process, each with its own advantages and disadvantages.
The Diesel Crew took into consideration many criteria when choosing a reactor catalyst. The first
consideration was whether the catalyst forms a homogenous or heterogeneous mixture with the
reaction mixture. Potassium hydroxide (KOH) dissolved in methanol is the most common catalyst for the
reaction. KOH works well but requires a washing step to remove the KOH. Because the KOH is extracted
with water in the washing step, KOH cannot be recycled, resulting in higher waste production and
operating costs. In addition, the water wash is not very effective as a continuous process because there
is not a large enough difference in density between FAME (0.88g/mL) and water (1.00g/mL). To reduce
total production time and implement a continuous system, a heterogeneous (solid) catalyst is incredibly
beneficial because the washing step is avoided and the catalyst can be reclaimed for use in later
reactions, minimizing costs and promoting good stewardship.
The team identified CaO as the best catalyst for the system, as CaO is inexpensive, insoluble in all of
the other components, and relatively non-toxic. More of the decision criteria can be found in section 4.9
Catalyst. Literature values for CaO reaction rates are available, but papers differed on the rates of
reaction that could be attained. The catalyst performance is very dependent on particle size, so the
team had to do a significant amount of reaction testing to confirm that CaO would work as a catalyst
and what conditions should be used (see reaction testing experiments in Appendix G-3). The team also
found that there were a variety of advanced reactor types that could be used to achieve faster reaction
rates. These reactors included but were not limited to microreactors, cavitation reactors, microwave
reactors, oscillatory baffled reactors, and motionless inline reactors (Mazubert, Poux and Aubin). The
team concluded that implementing a microwave reactor would be the most feasible for a system
purposed for use at a home or small institution. A summary of the research used for design decisions
can be found in 0.
A temperature of 60°C was chosen for the reaction, because it is as high of a temperature as can be
achieved without boiling the MeOH (64.5°C n.b.p. per MSDS). Safety considerations restricted the team
from increasing pressure to allow for higher temperatures without the MeOH boiling. Several batch
reactions were tested to determine which ratios of MeOH:WCO and CaO:WCO should be used
(Appendix G-3). The results of these experiments are shown below (Figure 3-1 and Figure 3-2).
6
Figure 3-1* Batch Reaction Results for Varying Catalyst Ratio
* Note: Highest catalyst ratio was run at slightly lower temperature, so expected conversion is higher than 0.5
From the results in Figure 3-1, the team concluded that a catalyst ratio of 283g:1L WCO should be
used. Several volume ratios were tested at this catalyst ratio.
Figure 3-2 Batch Reaction Results for Varying Volume Ratio
Unfortunately, the team was not able to do more reaction testing due to issues with ordering
catalyst, but the team decided on a MeOH:WCO vol. ratio of 1:1 to lower the duty required to vaporize
and condense excess MeOH. The team concluded that it was reasonable to make the assumption that
high enough rate would be obtained at a 1:1 volume ratio, since experiments in the literature usually
7
used a 6:1 molar ratio of MeOH:WCO, and a 1:1 volume ratio equates to a 7.75:1 molar ratio (Mazubert,
Poux and Aubin).
The team also desired to verify that microwave heating would yield faster reaction rates. A reaction
at 6:1 vol. ratio of MeOH:WCO and 113g CaO:1L WCO was repeated using a microwave for heating (see
Appendix 0). The conversion after one hour increased over four-fold, indicating that there was a
significant advantage to heating with a microwave.
The results from reaction testing confirmed the team’s choice to use CaO catalyst and microwave
heating. Based on these results, the team concluded to use the 1:1 vol. ratio of MeOH:WCO and 283g
CaO:L WCO. This information was very important in finalizing the design of the rest of the system.
8
4
Physical System Design
The following diagram outlines a brief overview of the process.
Agitator
Process Flow Diagram
Team #1- The Diesel Crew
Catalyst
Holding Tank
Updated: 5/14/2014
3-way Solenoid
Heating Coil
Thermocouple
T
Sprayer
Valve
Dirty
Waste
Cooking Oil
P-135
Microwave
Microwave PFR
PFR
I-1
Dewatering
Pump #1
Inline Mixers
Thermocouple
CSTR with
Agitator
Canister
Filter #1
T
I-2
WCO
Pump #2
Cascade Settling Tank
Methanol
Pump #3
Catalyst
Cake
P-139
Vacuum
Hose
Clean
WCO
Holding
Tank
Vacuum
Pump
Cold Water
Out
Methanol
Condensor
Polishing
Column
Cold Water
In
Biodiesel
Out
Me
O
Ou H
t
Biodiesel
Pump #5
Column
Separator
Methanol
Holding
Tank
Transfer
Tank
Glycerol Waste
Tank
Biodiesel
Storage
Tank
Distillation Column
Figure 4-1 Process Overview of Reaction System
The process starts with a batch de-watering process that removes water from the oil feed. The
pump and heater from the de-watering vessel are used to pump and heat the WCO and feed it to the
9
first reactor, a CSTR. The CSTR effluent then passes through a Microwave PFR to a semi-continuous
catalyst recovery unit. The Methanol from the product stream is then recovered and the product is
passed to the separator. The separator allows the heavy glycerol to settle out of the bio diesel product
and be collected as waste. The biodiesel product then goes through a polishing column to remove any
particulates from the reactor, such as particle fallout or remaining catalyst.
The user interface and controls are not shown on the diagram. The control system allows for lower
user interaction with the prototype while sensors, alarms and automatic emergency shut offs help
protect those in the environment near the reactor.
Some key properties for design are shown below in Table 4-1.
Table 4-1 Key Component Properties (at room temperature)
Component
Soy Oil
MeOH
FAME
Glycerol
Density
(g/mL)
0.926
0.792
0.88
1.261
Density
(lb/gal)
7.71
6.59
7.33
10.50
Molecular Weight
(g/mol)
872.6
32.04
292.2
92.09
Stoichiometric
Volume (gal)
1
0.129
1.060
0.0775
Note: Soy Oil and FAME MW calculated from relative abundance of fatty acids (see Appendix D)
4.1 System Housing
The components of the system needed to be attached to a supporting structure to hold them in
place.
Housing alternatives were evaluated for several criteria. First, the housing must be able to hold
all of the components, save for some of the material storage containers which could be placed on the
ground. Second, the housing must fit through a standard door in order to meet the team’s design
requirements. Third, the team required that the prototype be easy for a customer to transport;
therefore, alternatives with wheels were preferred.
Shortly after the project began, the team found a steel frame (Figure 4-2) with batch reactor
equipment installed that had been donated to the Calvin College Engineering department by Pfizer, Inc.
The frame was just the right size to fit through a standard door while still being able to hold large, heavy
system components, making it an ideal solution. This frame also had castors which met the criteria for
easy transportation. Other alternatives were more expensive than using the available frame, so the
team decided to adapt the reactor system to the frame with some modifications. Unused batch reactor
glassware and others components were dismantled and given to Phil Jaspers as requested.
10
Figure 4-2 Reactor System Pre-built Frame
4.2 Control System
4.2.1 Requirements
In accordance with the teams initial design objective of providing a simple and intuitive user
interface for the reactor system, the team designed and implemented a computer based control system.
Requirements for the control system were as follows:
 Visibly appealing and clearly labeled
 Intuitive for users of all backgrounds
 Provides an additional layer of safety to the reactor system
 Allows for both inputs and outputs
 Is able to provide feedback control of system components
 Affordable and within budget constraints
4.2.2 Programmable Logic Controller
The team decided to implement a computer based controller using National Instruments’ LabVIEW
software. LabVIEW was used to provide system control and create a simple user interface. The
engineering department at Calvin College provided the LabVIEW software. LabVIEW, short for
Laboratory Virtual Instrument Engineering Workbench, is a system-design platform and development
environment for a visual programming language from National Instruments (NI). LabVIEW has two
primary panels: a front panel display and a back panel block diagram. The interface shown in Figure 4-3
was created in the front panel to resemble the physical system layout and doubles as a process flow
diagram.
11
Figure 4-3: LabVIEW Front Panel Process Flow Diagram User Interface
12
The front panel consists of controls and indicators. The controls allow for user inputs such as pump
flow rates, manual control of microwave power output, and the opening and closing of valves. Indicators
display the various outputs from the reactor system such as temperatures from thermocouple readings
and tank fluid levels from pressure transducers. Details on the design of this layout are explained in the
following section (4.2.3). The back panel, otherwise known as the block diagram, is where the
programming takes place. Each control and indicator on the front panel has a corresponding block
diagram icon. There are numerous block diagram icons not shown on the front panel display that are
used to perform operations on the inputs and outputs. LabVIEW programming is then done through the
connection, or wiring, of these icons. Further explanation of the block diagram programming is provided
in section 4.2.5 and the full diagram can be seen in Appendix E. The system pumps, thermocouples, and
pressure transducers were manually calibrated, and the correlations were implemented through logic
programming in the LabVIEW block diagram. The collection of the front panel display and block diagram
coding compose an executable file known as a virtual instrument (VI).
4.2.3 User Interface
The LabVIEW software chosen for the control system has a fully customizable graphical user
interface (GUI). Significant effort went into designing a GUI that was representative of the physical
reactor system with an intuitive layout. The team used color coding to easily monitor and distinguish
between the on/off state of subsystems, temperature gauges, tank level indicators, and pipes. The team
chose to use a touch screen monitor for ease of use combined with large buttons and control dials.
To reduce the complexity of the front panel display the team used separate tabs. Seven additional
tabs presented detailed information on each subsystem of the reactor. These tabs include individual
tank level monitoring and temperature readings, as well as, feedback control adjustment for the heating
coils and microwave magnetron.
4.2.4 National Instrument I/O FieldPoint Modules
After the LabVIEW VI is run on the computer, it interacts with the physical system components
through four NI FieldPoint modules (Figure 4-4). Starting from the left, the first FieldPoint module is the
FP-2015 network module. This device is the brains of the FieldPoint strip and allows for communication
with the computer through an Ethernet connection. The FP-2015 is a real-time programmable logic
controller that can run compiled VI’s directly without connection to a computer, although this
functionality was not used. A 24 VDC regulated voltage supply, generously provided by Chuck Holwerda,
powered the FieldPoint module bank.
Figure 4-4: National Instruments FieldPoint Modules and Power Supplies
13
The second FieldPoint module is the FP-AI-110, an 8-channel, analog input module. The FP-AI-110
received signals from the five pressure transducers used to monitor tank fluid levels. The third FieldPoint
unit was the FP-TB-10 which is a universal I/O module that has multipurpose functionality. This project
did not utilize this module, but it was included with the control system for possible future connectivity.
The fourth FieldPoint unit was the FP-TC-120, 8 channel thermocouple input module. The FP-TC-120
monitored the six thermocouple probes used throughout the system. This module has a cold junction
temperature compensator and built in temperature linearization algorithms for the eight most common
types of thermocouples. These added benefits greatly reduced the amount of calibration and
programming required to obtain accurate temperature readings from the K and T type thermocouples
used. The final FieldPoint unit is a FP-AO-200 8 channel, analog output module. The team used FP-AO200 to output control signals to the pump controllers and solid state relays used in the control system.
Due to the high power requirements of this module, a separate 24 VDC power supply was used.
4.2.5 Control Loop Feedback Design
A crucial part of the reactor system was accurately controlling the power output of the microwave
magnetron. At full power, the microwave would easily evaporate all of the methanol traveling through
the plug flow reactor. This would cause high pressure buildup inside the tubing, possible melting of
inline mixers, and reduced conversion due to the formation of a separate, gaseous phase. The majority
of microwaves on the market do not have variable power output and those that due tend to be very
expensive. Traditional microwaves can only limit power output by the duration of time that the
magnetron operates- this is known as intermittent power control.
To maintain a relatively constant reaction temperature in our system’s microwave PFR, the team
implemented intermittent power control through the LabVIEW VI. A team member created the industry
standard proportional-integral-derivative (PID) controller in the VI block diagram (Figure 4-5). Inline
thermocouples on the inlet and outlet streams of the PFR provided feedback for the control loop
system. The user is able to choose a set point outlet temperature and the PID controller takes care of
the proper power cycling of the magnetron to achieve this temperature. A separate front panel tab was
made for the user to input controller variables and parameters (Figure 4-6). Using the LabVIEW PID
Toolkit functions, an auto tuning feature for the PID controller was added and is performed through a
guided step-by-step wizard. In addition to the PID controller, we programmed several safety measures
into the VI to ensure proper microwave functionality. In case of malfunction, we placed a manual
control on the front panel that is able to override the PID controller. If the temperature is exceeded a
high temperature alarm shuts down the microwave magnetron. This alarm is also wired into a warning
LED indicator on the front panel to alert the user of the specific system malfunction. For another layer of
safety, a team member connected the temperature alarm indicator to an audible alarm which sounds a
loud buzzer- alerting the operator.
The same PID controller system controlled the two heating coils used in the dewatering and
methanol recovery systems respectively. The full system layout can be seen in Appendix E.
14
Figure 4-5: Block Diagram of Microwave PID Controller in LabVIEW VI
Figure 4-6: Front Panel Microwave PFR PID Controller Interface in LabVIEW VI
15
The team fine-tuned the PID for the dewatering system heating coil using PID auto tuning. After
determining the new PID gains, the controller maintained the WCO temperature to within 0.26°C of the
set point temperature.
4.2.6 Electro-Mechanical Components
Solid state relays wired up to the FP-AO-200 module controlled many of the system
components. Solid state relays provide fast, reliable, and silent switching of power to the devices
they are connected to. The team used five solid state relays in the reactor control design, their use
and requirements are shown in Table 4-2: Solid State Relay Outline
. The relays used in the system were met and exceeded the maximum requirements.
Table 4-2: Solid State Relay Outline
Relay
Device Controlled
#1
#2
#3
#4
#5
Pump #1- Dewatering System
Pump #2 and Pump #3= WCO and Methanol
Heating Coil #1- Dewatering System
Heating Coil #2- Methanol Reboiler
Microwave Magnetron/Transformer
Power
Requirements
5 Amps
1 Amp
16 Amps
16 Amps
20 Amps
Switching
Frequency
NA
NA
< 10 Hz
< 10 Hz
< 1 Hz
4.2.7 Safety Implementations
Integrating a control system into our reactor design allowed for many additional layers of safety to
be applied. Each component of the reactor system that is connected to the FieldPoint modules has an
alarm indicator to signal any malfunctions or operations that stray from a set margin. These alarms are
all wired to the system buzzer which alerts the operator when attention is needed. During startup, each
alarm trigger can be turned off until steady-state conditions are achieved.
4.3 Material Storage
The reactor system requires a few materials to be stored nearby, such as methanol, WCO, waste
glycerol, and purified biodiesel. Storage containers have sufficient room for hold up, so the reactor
system run time is not limited by the available reactants, (WCO and Methanol), nor by the storage of
products (biodiesel and glycerol). High-Density Polyethylene, or HDPE, is a tough plastic that is used to
store various chemicals and comes in a large variety of volumes. All of the system components do not
react with HDPE, and the waste can also be stored in HDPE. The team used 15 gallon HDPE drums for
the WCO, the clean WCO and the biodiesel product. The team used a 5 gallon HDPE drum for the
methanol reservoir.
4.4 Tubing
The tubing involved in the reactor system must be able to hold up to the relatively harsh solvents of
methanol and biodiesel, be able to hold up to the caustic calcium oxide catalyst, and withstand the
moderately high operating temperatures of 60-70°C. Another major factor in choosing the type of
tubing to be used in the reactor system is cost. Other factors considered were the size of tubing
16
available, flexibility, and ease of connectivity. A summary of the design criterion and determination of
selected tubing is shown below, as seen in Table 4-3Error! Reference source not found. below.
Table 4-3: Tubing Decision Matrix
Low Density
Polyethylene
(LDPE)
Polytetrafluoroethylene
(PTFE)
Fluorinated
Ethylene
Propylene
(FEP)
Nylon
Polyvinyl
Chloride
(PVC)
Polycarbonate
(PC)
7
7
Characteristic
Weight
Copper
316
Stainless
Cost
8
2
1
10
1
4
6
Chemical Resistance
10
5
9
3
10
10
8
6
2
Flexibility
5
3
1
9
3
7
6
10
1
Heat Resistance
8
10
10
2
10
10
5
4
10
Size Availability
3
9
9
10
9
10
10
7
6
Ease of Connectivity
4
3
3
10
10
10
10
8
10
Sum
38
32
33
44
43
51
45
42
36
200
222
241
270
317
268
251
219
Weighted Total
higher = better)
The decision matrix showed that fluorinated ethylene propylene (FEP) was the clear choice for the
project. It is relatively inexpensive when compared to 316 stainless steel piping and PTFE tubing,
chemically inert, and can withstand very high temperatures. FEP was chosen for the tubing and nylon
was chosen for the fittings due to its availability and cost while maintaining good chemical and
temperature resistance.
4.5 Pumps
The team had difficulty choosing the right pumps for the system. The reactor design required five
different pumps to be integrated into the system, each with very different requirements (Table 4-4).
Table 4-4: Biodiesel Reactor Pump Requirements
Description
Pump #1
Pump #2
Pump #3
Pump #4
Pump #5
Subsystem(s)
Waste Cooking
Oil (WCO)
Filtered
WCO
Methanol
PFR to CSTR
Glycerol
Removal
Biodiesel with
small amount
of glycerol
What is being
pumped
Max Fluid
Temperature (°C)
Required Flow Rate
Metering Required
WCO with fine
contaminants
Filtered
WCO
Methanol
WCO; Methanol;
Calcium Oxide
Slurry; Biodiesel;
Glycerol
100
100
30
70
80
100-200 mL/sec
No
1-2 mL/sec
Yes
1-2 mL/sec
Yes
2-4 mL/sec
Yes
1-2 mL/sec
Yes
The WCO dewatering subsystem required a high flow rate pump that was able to hold up to high
temperatures, around 100°C, but did not need accurate flow rate metering. We chose a small centrifugal
pump for the dewatering system due to its high flow rates and good handling of fine particulates that
may be present in the WCO as it has not yet passed through the fine filter at this stage.
17
For the rest of the system, precise flow rates are required. Fortunately, Calvin College had a surplus
of FMI metering pumps donated to them from the 2007 Pfizer plant shutdown in Holland, MI. The FMI
metering pumps have a unique valveless pump head that provides reliable flow rates and is able to be
replaced with different size heads depending on the flow rates required. As noted on the FMI product
website, these valveless pumps are also able to handle fine slurries without clogging or deterioration.
Three stroke rate controllers were also available for use from Calvin. These stroke rate controllers
convert the AC wall voltage to the required DC voltage for the pumps and allow for manual speed
control. Two of the controllers were a newer model that also allow for speed control from a 4 – 20 mA
input signal, perfect for integration with the LabVIEW control system through the FieldPoint I/O
modules.
4.6 Coarse Filter
The coarse filter removes all large food pieces from the WCO from frying food. The course filter
consists of a fine wire mesh, 177 micron hole width and a stainless steel frame (Figure 4-7). The team
spot welded the mesh around the steel frame in order that the mesh fit snug into the inlet of the
dewatering unit. With this design a large volume of oil can be poured into the tank without worry of
backup in the filter. The filter was effective, removing large and small particulates from the waste oil,
and is easily removed for cleaning.
Figure 4-7 Filter Mesh for Dewatering System
18
4.7 Dewatering
The purpose of the dewatering system is to dry the WCO. Water is detrimental to the reaction.
First, water will poison the catalyst, forming calcium hydroxide and severely limiting the conversion.
Second, the presence of water in the reaction will push side reactions that form soap and will result in
an emulsion. Finally, water present in the reactor slurry can result in the hydration of the triglycerides to
FFA instead of methylating the triglycerides to form the desired methyl esters. The limit of FFA in the
final diesel product is very low, an acid number of 0.5, and thus this side reaction must be limited.
The unit design (Figure 4-8) below, works as a small batch process before the reaction system. Oil is
poured through the course filter into a 15 gallon drum. The pump draws oil out of the bottom of the
drum past a heating coil and sprays it back into the top of the drum. A spray valve fans out the stream
for better mass transfer. The circulatory system allows for good mixing of the oil, as well as rapid heating
of the solution. In an effort to save money, the team was able to 3-D print the spray valve from acrylic
plastic. The team tested the plastic for heat and chemical degradation in an oil bath at 110 °C, see
Appendix G-2. The test revealed no signs of thermal or chemical degradation. The CAD drawing of the
spray nozzle is available in section J-1 Sprayer Valve for Dewatering Unit.
Finally, the team chose a heating element that worked on 120 volt power, but still heat the oil
quickly. The team decided against a higher voltage for easier use of our reactor system at any location.
The team purchased a 2000 W heating element capable of heating 10 gallons of oil to 100 °C in 45
minutes, see Appendix L-1 Dewatering Calculations for details. To ensure the safety of the system, the
team chose to contain the heating element within 1 inch galvanized steel pipe, protecting the
surrounding area from possible failure of the heating element.
19
Figure 4-8 Design of Dewatering System
4.8 Fine Filter
After the WCO has been dewatered, the WCO is pumped through a canister filter from Ametek™
into a HDPE holding tank. Available for the team’s use was 10 micron polypropylene filter cartridges,
perfect for the sediment removal as well as resistant to the waste cooking oil. The team chose a filter
cartridge, because the housing is easily accessible to the end-user and replacement cartridges are
affordable and readily available over a large range of particle size.
4.9 Catalyst
The selection of catalyst was a key decision for the Diesel Crew. The team selected several
criteria for selecting the catalyst, summarized in the decision matrix shown below (Table 4-5). Due to the
small budget and desire to achieve comparable production rates to the established batch processes, the
team emphasized cost, availability, and reaction rates when making the decision. Secondly, the team
desired to pursue a continuous process and required the catalyst to be easily separated from the
biodiesel.
Cost was an important criteria when deciding on the most appropriate catalyst. Research
performed by the team led to the discovery of many exotic catalysts that could be used to achieve high
20
FAME conversion, but the costs of these exotic catalysts far exceeded the budget. Cost considerations
alone severely limited the number of possible catalysts for the prototype reactor.
Catalyst tolerance to FFAs, water, and other contaminants was also taken into consideration.
Liquid catalysts have a greater tendency to form soaps when FFAs and water are present in the reactor
mixture. The soap, a great nuisance, clogs system components and complicates further separation of the
reactor products. Solid metal catalysts are less susceptible to soap production, but they can be easily
poisoned or inactivated by water and FFA contaminants.
The final consideration made when choosing a reactor catalyst was the solubility of the catalyst
in the biodiesel product. Many solid metal catalysts under consideration have moderate solubility in
biodiesel requiring additional purification processes that add significant costs. Due to these factors, the
amount of leaching into biodiesel was factored into our choice of catalyst (Science Lab, Inc).
Table 4-5 Design Decision Matrix for Catalyst Choice
Criterion
Type
Ease of Separation
Cost
Reaction Rates
Total Reaction Time
Availability
Material Handling
Score
Weight
-7
10
8
6
9
3
--
KOH
Liquid
3
9
7
3
9
4
278
CaO
Solid
8
10
7
8
7
3
332
MgO
Liquid
7
9
5
8
7
5
305
ZnO2
Solid
8
3
10
9
6
5
289
FeSO4
Liquid
5
9
8
3
7
5
285
The team chose CaO, a solid, homogenous catalyst. Commercially, CaO is readily available; it is a
component of cement and many cement supply companies sell it. CaO is relatively inexpensive for an
industrial catalyst, roughly 2000 pounds can be bought for $100-$200. The team desired to operate the
reactor system as a continuous process and therefor had to steer away from the typical homogenous
KOH and HCL liquid catalysts. The team chose CaO for its low cost, moderate to high conversion rates,
and resistance to poisoning; further information regarding the properties and chemistry of CaO can be
viewed in Appendix B. Using a solid catalyst also allows for easier recovery and recycle. Although the
team did not investigate the process to regenerate and reuse the catalyst, keeping catalyst recycle as an
option was critical for the team’s value of stewardship.
4.10 Reactor
The reactor is the heart of the biodiesel generator. The chosen reactor design has a major
impact on the overall cost of the system; therefore a large focus was placed on this topic. The reactor
had to achieve high FAME conversion, 94-100%, at the required reactor flow rates. The reactor had to
incorporate a CaO catalyst of very small particle size, so a packed bed reactor would not work due to
excessive pressure drop. Research showed that a microwave reactor would increase conversion over
traditional heating, and a test batch reaction confirmed our literature research.
21
4.10.1 Microwave PFR
The use of microwave reactors for the production of biodiesel is a recent development.
Microwave irradiation has two major benefits: no external heating is required and the catalyst efficiency
is significantly improved. Eliminating the need for another heat source, microwave irradiation is a highly
efficient way to heat the reactor contents. Microwave irradiation also encourages mixing on the
molecular level. This promotes transesterification of triglycerides with methanol, reaching near
complete conversion depending on which catalyst is used. Reports of 99% conversion in 10 seconds are
reported at high power outputs. Our research showed that household microwaves could be used, so the
need for the purchase an expensive microwave reactor was eliminated (Mazubert, Poux and Aubin).
When we tested an Emerson-brand home microwave, we found thermal hotspots present within
the microwave cavity (Appendix G-5). A 1200 watt Amana microwave (model# RFS12SW2A) was
donated by Subway, repaired, and used by Team One with a PFR. The Amana microwave utilizes a stirrer
fan to scatter microwaves, preventing nodes of microwave density from forming.
Observations in lab indicated calcium oxide settled out of suspension within a matter of seconds
of ceasing agitation. We found that static inline mixers could allow the reaction mixture to pass through
a PFR as a slurry without the catalyst settling to the bottom of the tubing, so 17 static mixers of the type
shown in Appendix K-4 were spread throughout 100’ of FEP tubing to assist with catalyst suspension.
However, control of the microwave power levels is not completely flexible, for example, power settings
on the microwave are managed by varying the gap of time between 12-second periods of magnetron
operation. In order to avoid boiling the methanol in the reaction mixture, which would very rapidly
displace the slurry from the PFR, preventing further microwave assistance. At a 1:1 methanol to WCO
ratio, we estimated a flow rate in the PFR of 2.42ml/s. With a rated power output of 1200W and a
reactant inlet temperature of 55⁰C, this means the microwave needs to operate at roughly 3.1% of
maximum power output. Furthermore, based on the results seen in an hour-long microwave batch test
(Appendix 0), if we tripled the length of the PFR to 300’, the space-time is still insufficient to achieve
adequate conversion. All data and supporting calculations can be viewed in Appendices L-4, 0, L-6.
4.10.2 CSTR
To meet this challenge, the team implemented a CSTR with catalyst slurry in series with and
preceding the microwave PFR. The CSTR precedes the PFR because in a CSTR the bulk concentration is
the same as the reactant’s outlet concentration; because the rate of reaction is determined
concentration in the reactor for CSTRs, placing the CSTR where the effluent reaches 95% conversion
would be highly inefficient. The CSTR is not directly heated with a microwave, but the CSTR adds space
time and achieves significant conversion, allowing the remaining of the conversion to be achieved in the
PFR. The CSTR maintained its temperature by running hot ethylene glycol-water mixture (glycol additive
helps prevent water vaporization) from a CTB through the glass jacket surrounding the reactor interior.
By setting the feed rate on the pump to the PFR equal to the sum of the rates of feed into the CSTR, the
team ensured the volume of liquid in the CSTR would remain at steady state. The team included a
rupture disk to allow for the future possibility of a pressurized system that could operate at
temperatures above the boiling point of methanol, but used a condenser to maintain atmospheric
pressure without releasing methanol vapor.
We set the CSTR agitator to run a 4-bladed, radial-flow impeller as fast as possible without
excessive vortexing or precession. To ensure good mixing within the CSTR, four baffles were added to
the reactor. In accordance with literature recommendation for slurries, the baffles are about 1/10th of
22
the tank diameter wide, and are spaced from the CSTR wall to prevent catalyst buildup (Perry, Green
and Maloney). Because the walls of the CSTR are glass, the team used plastic pads to suspend the
baffling assembly in the CSTR.
4.11 Catalyst Recovery
One of the team’s biggest challenges was designing a system to reclaim the catalyst. Vacuum
Filtration works very effectively in a batch process, but the large amount of very fine particles causes
filters to clog too quickly in a continuous process. Still, the team was committed to developing a system
with CaO, because CaO can be recycled consistent with the team’s values of sustainability and
stewardship. In addition, by reclaiming the catalyst, the costs are decreased for the end user.
The challenge was designing a catalyst recovery unit that could handle the required flow rate of the
reactor and not clog during the operation cycle. Ideally, the unit would be able to be replaced without
shut down of the entire system. The team investigated several designs, and the chosen design was a
settling tank cascade (Figure 4-9) in which the reactor effluent is passed into a settling tank where the
CaO is allowed to settle to the bottom and the liquid cascades over into the next settling compartment
for remaining catalyst to settle out. This allows for a large amount of catalyst to settle before the
catalyst recovery unit reaches capacity, and the operation must shut down temporarily. The down side is
that a large volume of reactor effluent is also held up resulting in two consequences; the large volume
requires a long time to fill the tank for initial start-up, and secondly the large space time in the tank
allows for heat loss from the biofuel before entering the methanol column, requiring extra work from
the heating element in the reboiler.
23
Figure 4-9 Settling Tank Seen from Feed Side of Tank
The team designed the tank to be twenty four inches long, twelve inches wide, and twelve inches
tall. The tank included a cover with solid cell weather stripping foam to help seal the tank from
methanol vapors escaping. The team outfitted three compartments, the first to catch the catalyst, the
second as a safety catch, and the third as a small holding cell to allow for better flow to the next
subsystem. The team placed a six inch wall at twelve inches, and a 4 inch wall at 20 inches from the feed
side wall. This results in a storage capacity of 3.75 gallons and 1.6 gallons in the first and second
compartments respectively. For a flow rate of 2 mL/s, the space time in the settling tank is about three
hours. The team estimates that the catalyst will occupy 28% of the flow volume, resulting in the tank
reaching capacity in six hours see Appendix G-8 regarding estimations.
4.12 Methanol Recovery
To help tilt the FFA and triglyceride reaction equilibria toward the desired FAME product, the
reactor feed contains significantly more methanol than the required stoichiometric amount. As a result,
the unreacted methanol needs to be recovered and recycled back into the reactor.
24
Methanol recovery and recycle is desired for several reasons; the first of which is the produced
fuel’s quality. If unused methanol is left in the reactor effluent, the product will contain excessive lowboiling methanol which would adversely affect the diesel combustion characteristics. The second reason
for methanol recovery is cost; at a MeOH:WCO molar ratio of 7.75:1 in the feed, huge amounts of
unreacted methanol would be unnecessarily wasted if unrecovered, exhibiting poor stewardship. This
would also require a much larger fresh methanol feed storage tank, which runs contrary the stated goal
of producing a smaller reaction system. Furthermore, the excess methanol cannot simply be boiled off
or allowed to evaporate into the air, as methanol is a flammable, low-boiling, (64.5°C n.b.p. per MSDS)
toxic substance (Science Lab, Inc), posing an environmental and safety hazard.
A continuous distillation process was necessary for the MeOH recovery system (Pictured in
Appendix M-2). The Diesel Crew’s design utilizes vacuum distillation to evaporate the relatively volatile
methanol off of the reactor effluent at a lower temperature than necessary at atmospheric pressure. A
water-cooled heat exchanger is used to condense the methanol into the MeOH feed tank. With perfect
insulation, the heating and cooling requirements would be 0.81 and 0.78kW, respectively (see Appendix
L-3). In order to supply heat to vaporize the MeOH, a 2 kW electric heating coil is mounted in a reboiler.
Even with these components, it is difficult to obtain a pure separation, despite that biodiesel does not
evaporate at the temperatures the MeOH recovery unit is operating under. To achieve the necessary
separation, a packed column was used. The column is packed with Raschig rings. Assuming relatively
good insulation of the settling tank, the feed to the top of the column should be at approximately 50°C.
At 50°C, MeOH boils at a pressure of 55.7 kPa, so the required vacuum must lower than 55.7 kPa. As a
sealed system, there is little risk of methanol escaping into the atmosphere.
The column was chosen because packed columns are typical for continuous MeOH recovery in
industrial biodiesel production plants (Kotrba), and the team was able to borrow a packed QVF pilot
plant column from the department. The condenser was donated by Pfizer, but the condenser used
different connections than the QVF column. A part was designed and 3-D printed that connects the
packed column to the condenser, with a feed and distributer (Appendix J-2). The team did not have a
large enough budget to buy a vessel for the reboiler, so a five inch inner diameter aluminum pipe was
used as a vessel. Two pieces of aluminum were milled to give the necessary holes to connect the column
and clamp the plates of aluminum on the top and bottom of the pipe using threaded rod. The cost of
PTFE flange gaskets for between the plates and pipe was too high, so the team made flange gaskets by
wrapping a cardboard ring with several layers of PTFE tape (Samohon).
Holes were tapped and threaded in the bottom plate for a 2 kW heating element and drain. Holes
were tapped and threaded for a thermocouple in the side, ensuring that the thermocouple would not be
too close to the heating element. A hole was also tapped and threaded in the side of the pipe for a side
draw an inch above the top of the heating element. The PTFE gaskets and tri-bolt connections that came
with the packed column were used to connect the column to the top plate and to the distributer. A
schematic of the system can be found in Appendix K-2.
4.13 Glycerol Separator
The glycerol produced from the reaction can be mechanically removed via a two phase, liquid-liquid
separator due to general insolubility of glycerol in FAME and substantial differences in density compared
25
to FAME (~1.26g/ml vs. ~0.88g/ml). Some glycerol can be removed in the final biodiesel purification
column, but this separator is necessary to avoid clogging the final purification system with glycerol.
A settling tank uses gravity to separate substances based on density. This is a low-cost, passive
system requiring little to no added energy other than that already possessed by the effluent. Because
the glycerol is soluble in MeOH, the team had to stage this operation after the MeOH recovery. Some of
the glycerol is separated co-currently with methanol, as some of the glycerol falls out of solution in the
re-boiler. The rest of the glycerol is separated in this separator.
The team constructed the density separator out of 1.5 inch diameter clear PVC tubing, with caps on
each end, for a total height of approximately 15 inches, see appendix section M-3 Density Separator.
The team tapped holes in the column; at the bottom for a glycerol drainage valve, approximately at half
the height for the column feed, and 1.5 inches below the top for the biodiesel side draw. The
connections were polypropylene compression fittings, using PTFE tape to help provide the seal. The
system works well because the glycerol can be removed from the system without shut down, and
enough volume was used to maintain a long period in between glycerol drainage times. For a total
volume of 434 mL, and a glycerol volume of 232 mL, the column can operate for fifty minutes without
needing to be drained of glycerol.
4.14 Polishing Column
The final step of the reactor process is the polishing column. The polishing column, otherwise
known as a purification column, consists of a large cylindrical tube filled with ion-exchange polymer
beads that prohibit the passage of various contaminates while allowing the biodiesel to pass through.
Possible contaminants include small amounts of glycerol, CaO catalyst, remaining mono-, di- and triglycerides, and any remaining free fatty acids. This is a crucial step in producing a quality biodiesel
product that meets all ASTM standards. Polishing column technology is well established and has not
changed much since Rinnova’s design. The team has chosen a very similar design to Rinnova’s polishing
column based on its effectiveness at removing most contaminants, the ability of the column to work in a
continuous fashion, and the affordable nature of the column. There are five ion-exchange resins
commonly used for biodiesel purification, each with its pros and cons. Due to limitations of time and
money, the team has been unable to test these five polymers for their effectiveness at removing the
CaO and other contaminants. However, Professor Sykes provided The Diesel Crew with a contact at the
DOW Chemical Company who was able to supply the team with five pounds of Amberlite™ BD10Dry™ to
perform testing.
The team used 1.5 inch diameter, clear PVC tubing for the column, with a PVC cap at the top of the
column (Appendix M). The column is approximately thirty eight inches long, designed to hold twelve to
fifteen inches of dry resin, or approximately 0.8 pounds. This is enough resin to treat approximately 720
to 1280 pounds or 140 gallons of biodiesel. The resin has impressive expansion properties, expanding by
6-15%, 130%, or 150% when saturated with biodiesel, methanol, or water respectively. This results in a
potential height of twenty seven to thirty three inches of packed height if enough methanol were to be
absorbed by the bed. This expansion is likely to occur as methanol is used to regenerate the resin once
saturated with glycerol and other contaminates (Haas). See Appendix section L-2 for expansion and
pressure drop calculations.
26
The use of a packed resin column requires that the resin be able to be removed upon depletion.
The team allowed for this criterion via a removable acrylic cap at the bottom of the column, printed
using the department’s ProJet HD3500 plus. The CAD drawing is included in the Appendix section J-3.
The cap is composed of two parts, a male thread that is glued to outside of the tube, and a female
thread to cap the column (Figure 4-10). The cap is designed to house 177 micron wire mesh that acts as
the containment for the resin beads. This cap allows for easy removal of the resin bed once worn out,
while still providing a tight seal.
Figure 4-10 Bottom Cap to Polishing Column with Wire Mesh Inserted
27
5
Suggestions for Design Improvement
5.1 Continuous Settling Tank Operation
In order to make the catalyst recovery continuous, the team suggests that augers with decreasing
thread spacing be used to push the catalyst out of the settling trays. The decreasing thread spacing
compacts the CaO and presses the fluid out, resulting in little product loss via catalyst removal. A similar
idea is implemented with injection molding technology. Due to our limited construction ability, we built
a settling tank without the augers; however, if our project was made commercial, we would recommend
the auger system.
5.2 Continuous Catalyst Feed System
The team determined that a continuous catalyst feed system was outside of the scope of the
project. Feed systems are very complex, but the use of CaO requires an air tight feed, further
complicating the design. The team attempted to make a catalyst trickler system. The trickler system is
composed of a column filled with the catalyst with a secondary cylinder passing through the column at a
high angle (Figure 5-1). The cylinder rotates within the column, catching catalyst via drilled holes on one
side. The rotation allows for a certain amount of catalyst to fall into the cylinder and then through the
cylinder into the reactor. This design in theory had two very nice features; the feed rate of catalyst is
controlled by the rotation speed of the cylinder and secondly the system is closed off to air. This design
was not successful, the catalyst packed too hard into the column, and the bridging of the catalyst
prevented the cylinder from collecting catalyst in the holes.
Figure 5-1 Trickler Prototype Testing.
The team considered two additional designs for catalyst feed. The first being a hopper feed system
with a star valve to control the drop rate of the catalyst, while preventing any methanol vapors from
escaping the reactor. The second was a vibrating conveyor belt system that could evenly add catalyst to
the reactor system.
28
5.3 Improved Microwave Operation
By rerouting the catalyst recovery effluent and utilizing the microwave’s efficient heating to
vaporize the methanol, the duty on the heating coil in the methanol could be greatly reduced, although
this would likely be offset by increased microwave power. However, this would help increase product
homogeneity by allowing the microwave to operate for longer periods of time (i.e. at a great %-setting
of maximum power) without prematurely boiling the PFR reactants.
5.4 Improved Heat Capture
As shown in Appendix L-7, approximately 25% of the energy found in a gallon of pure biodiesel is
needed to produce that gallon of fuel. This contributes a significant amount to the unit cost of each
gallon, removing $1.30 of profit via electricity expenses from each and every gallon produced. If the
distillation column’s bottom products were used with a heat exchanger to help warm the CSTR jacket,
modest energy savings could be realized.
5.5 Improvements to Control System
Many improvements could be made to the reactor control system. A 3-way solenoid valve could be
installed on the dewatering system to allow for computer control of the flow direction, either
recirculating in the dewatering system or sent to the filtered WCO tank. Additional 3-way solenoid
valves could be installed throughout the system to allow for computer controlled sampling. A carefully
weighted float sensor could be installed in the glycerol settling tank to allow for automatic drainage of
the glycerol byproduct. The float sensor would be buoyant in the glycerol but not in the biodiesel,
allowing for measurement of the glycerol level. Alternatives to a float valve would be a visual sensor
that is able to distinguish between the two liquids based on color, absorbance, or refraction, or an
ultrasonic sensor that is able to sense the changes in density. A variable rate needle valve could be
implemented after the polishing column to control the rate at which the biodiesel passes through the
ion-exchange resin. An inline flow sensor could measure the amount of pressure drop caused by the
inline cartridge filter after the dewatering system. This would allow for monitoring of the filter cartridge
plugging, and could be used to indicate to the user when the filter needs replacement.
29
6
Budget
Calvin College graciously provided the team with a $1,800 operating budget. The team’s line item
estimation for the project was $2,228.50, not including a control system. With a thirty percent
contingency, the team thought the project could be completed with $2,897.05 This estimation
accounted for many of the parts that the team could acquire from Calvin, such as pumps and some
glassware. The team was able to use LabVIEW software and field point modules that Calvin was not
using, and many other items were obtained from Calvin or donated, which allowed the team to finish
within budget. The team accomplished the project under budget, spending $1637.86 of the allotted
$1800. However, the team under estimated the value of equipment borrowed and/or donated. The
team estimates that the value of this equipment is nearly $20,000. Although the team severely
underestimated the cost of the project, the team did manage to complete the project with the allotted
budget. The itemized spending can be found in Appendix F.
30
7
Safety Concerns
The team consulted the material safety data sheets (MSDSs) for the primary chemicals used to
find the care that should be taken while working with the chemicals. None of the chemicals used in this
project should be ingested, and care should be taken to make sure that they aren’t inhaled, as all of
these chemicals have some negative health effects. However, the main concern is flammability of MeOH
and FAME (Advanced Organic Materials). The NFR safety labels are shown in Figure 7-1 (Science Lab).
MeOH
Soy Bean Oil
FAME
Glycerol
Figure 7-1 NFR Safety Labels
Hazardous Material Safety Identification System (HMIS) labels are shown in Figure 7-2.
MeOH
Soy Bean Oil
FAME
Glycerol
Figure 7-2 HMIS Labels
HMIS personal protection designations:
A – Glasses
G – Glasses, Gloves, Respirator
H – Glasses, Gloves, Synthetic Apron, Respirator
In addition, Calcium Oxide, the chosen reactor catalyst, is slightly reactive with water and can cause
chemical burns.
Proper protection was utilized by the team in working with the chemicals in this project. Especially
with flammable chemicals, electricity can pose a hazard. Care was taken to make sure OSHA
requirements were met with regard to electrical connections and wiring, so there were not any ignition
sources for the flammable chemicals. The team consulted an electrician from the physical plant in order
to meet these requirements.
One part of the design consists of using a microwave. Operating a microwave for long periods of
time can become a safety concern. The team addressed this by making sure no materials stayed in the
microwave that absorb microwaves, specifically certain metals and certain plastics that slowly degrade
when exposed to microwaves.
31
Waste can also pose as a safety hazard if not properly taken care of. All containers used during the
experimentation were properly labeled and carefully transported when needed. HDPE containers were
chosen as containment vessels. Dr. Tatko and Rich Huisman of the Chemistry department were
consulted about dealing with chemical waste. As the team did not successfully receive catalyst to run
the pilot plant, only a small volume of product was produced in the lab.
32
8
Environmental Considerations
The environmental impact of this project comes from two viewpoints, a direct and indirect
impact. The direct impact is the result of interaction of the reactor and the immediate environment
surrounding it, extending to the locale of where reactants were obtained and where the products are
distributed. The indirect impact is the potential influence the technology of this kind can have on the
physical world.
The direct impacts on the environment are positive, however a negative impact can be made if
the waste is not disposed properly. With that in mind, Team One attempted to incorporate the “Five
R’s” of responsible waste management in order of priority: Refusing to create waste when possible,
Reducing the amount of waste produced, Reusing materials when possible, Recycling waste that is
produced, and Replacing only if the other “R’s” have been already weighed. The team designed and built
a system that uses up (i.e. reuses) waste, a very positive effect, as the earth has a very limited amount of
room for garbage. The reactor system also produces a hydrocarbon fuel source that reduces the amount
of carbon released to the Earth’s surface and atmosphere by replacing petro diesel. Glycerol, the second
product of the chemistry, can potentially be used for a variety of tasks and products and was disposed of
appropriately. In fact, many waste water treatment plants will welcome glycerol as it makes for a good
feed for the bacteria in the anaerobic digester, even if the glycerol isn’t used towards making another
product. Lastly, methanol, a very volatile chemical, is used in the reaction, and unfortunately is quite
harmful for people. The team took great care in the design and construction of the prototype to ensure
that no methanol leaked from the system and exposed people in the surrounding environment to
methanol vapors.
Technology of this kind has the potential to have a very positive impact on the environment. As
mentioned previously, waste is not only being handled with care, but also reused, furthering the role of
humans as good stewards of the resources God has blessed us with. In addition, the product of this
“waste” is valuable fuel that can replace regular petro diesel, without losing much performance of the
engine. This fact is key as the dependency on crude oil, a non-renewable resource needs to be reduced.
Lastly, as the biodiesel industry continues to grow, a very large amount of glycerol is produced as a
byproduct. This glycerol can be implemented in many different uses, such as, anaerobic digesters,
livestock feed, and purified glycerol has medicinal and personal care product benefits (Yang, Milford and
Sun). Lastly, when biodiesel is blended with petro diesel, the carbon dioxide and sulfur dioxide emissions
are reduced (Agency). This team recognizes the benefit of these impacts, and these benefits
supplemented the attractiveness of the project to this team.
33
9
Team Member Responsibilities
9.1 Adam Alexander
Adam Alexander was responsible for three different aspects of the project: lead process researcher,
team webmaster, and pseudo-electrical engineer. First semester, Adam focused on pinning down the
reaction chemistry to be used in the reactor system. Later, his efforts were geared towards determining
the best reactor design for use in the small-scale, continuous system. Adam was also the team
webmaster which involved the responsibilities of creating and maintaining The Diesel Crew’s website.
Adam’s other contribution was in designing and implementing the reactor control system. With no prior
experience in this area, Adam dove in head first and was able to aggregate a functioning control system.
Along with these primary responsibilities, Adam helped his teammates in designing and implementing
various other system components.
9.2 Michael Lubben
Mike was the lead lab technician, designing and performing most of the reaction experiments and
other miscellaneous experiments. Mike was also in charge of design and construction for the MeOH
recovery unit, catalyst feed, and CSTR reactor. Some of the analysis also fell under Mike’s jurisdiction, as
Mike developed the method for solubility testing and performed all solubility tests. In addition to these
primary responsibilities, Mike worked with his team mates on the rest of the project to help bring the
goal to fruition. Mike also helped present the team’s work throughout the year, periodically making and
displaying posters documenting the team’s project and progress.
9.3 Angus Richeson
Angus served as second process researcher, investigating various catalysts and process alternatives
for project suitability in the fall. He investigated the business and economic background of the current
biodiesel industry. Angus also assisted in lab reaction and catalyst regeneration tests, and developed
and constructed the PFR. In addition to these areas, Angus made a special effort to support and assist
the other team members whenever needed.
9.4 Thomas Voss
Tom had three primary responsibilities regarding the team project. First, Tom was the organizer of
the team, keeping everyone aware of deadlines and due dates. Tom managed the team calendar and
tried to establish good communication between the team members. Secondly, Tom was placed in
charge of establishing the HPLC method. He worked extensively with Professor Tatko to develop the
analytical procedure to obtain quality results. Third, Tom was in charge of the construction of many of
the sub systems. He worked in the metal shop under the guidance of Phil to produce various parts for
the reactor system. Finally, Tom helped out other team members as needed in order to successfully
complete the project as a team.
34
10 Conclusion
The Diesel Crew was able to successfully design and prototype a continuous system for biodiesel
production. Calcium Oxide was determined to be an inexpensive solid catalyst that could be easily
isolated and recycled, giving an advantage over the traditional KOH catalyst. The final system meets
design goals of being small enough to fit through a doorway with only moderate deconstruction, safe,
and competitive with the KOH batch reaction. Two significant innovations in the prototype are static
mixers to achieve a slurry in a PFR and a microwave reactor to achieve higher conversion. Unfortunately,
the team was not able to do extensive system testing due to some issues with the catalyst supplier, but
the lab testing, design work, and calculations are sufficient enough to say that the prototype should run
well after some further optimization.
There are some design improvements that could be made, as the system is not entirely continuous
or automated. A CaO feed system with a star valve would be the next addition. A system to make the
catalyst recovery completely continuous could also be implemented. Furthermore, a more robust
control system would be necessary to make the system fully automated and more user-friendly.
Even if these improvements were made, the team concludes that a continuous reaction system is
not very feasible for a small institution or home biodiesel producer. The large number of difficult
operations results in an expensive system that takes up more space than a batch reactor system and is
not easy for someone with a non-technical background to operate. Furthermore, safety becomes more
of an issue with a continuous system because of a greater risk of leaks and difficulty in sustaining steady
state operation. A batch reactor is still the best for a small institution or home biodiesel producer,
though a batch process with CaO is competitive with a KOH batch process.
At the beginning of the year, the team was told that if they did a good job with the prototype then
there was a possibility of keeping it around as an example pilot plant to show future students. This
prospect interested the team greatly, as the members of The Diesel Crew thought that running a pilot
plant is both interesting an educationally beneficial. Upon project completion, both Dr. Wayne
Wentzheimer and Dr. Aubrey Sykes expressed interest in keeping the system around next year, which
the team considers another goal successfully reached.
35
11 Acknowledgements
The Diesel crew would like to thank the following organizations and people for their
contributions to this project this year.
Calvin College Engineering Department
-for the instruction from all the professors, advice on group management, and the technical
resources the department provided. In addition the Engineering Department provided a substantial
portion of the budget.
Dr. Aubrey Sykes
-Professor Sykes was the team mentor for the senior design class. He communicated with the team
about current progress, giving suggestions on how to stay on task as well as technical advice when
needed.
Phil Jasperse
-Phil helped the team with construction of the prototype by offering assistance and advice on
working in the metal shop.
Bob DeKraker
-Bob DeKracker was a significant resource in ordering major components and parts for the
construction of the prototype.
Bob Aupperlee
-Bob Aupperlee met with The Diesel Crew as an Industrial Consultant. He served as a third party
contact that could understand the scope and requirements of the project and give helpful critiques and
concerns. The team met with Bob once in the fall semester and once in the spring semester.
Chemistry Department
-The Calvin College Chemistry Department graciously allowed The Diesel Crew to use space in the
organic synthesis lab for experimental work. In addition, The Diesel Crew was allowed access to the
chemical stock of the department.
Dr. Chad Tatko
-Professor Tatko was a significant help for the development of the methodology for HPLC analysis.
He found an unused HPLC instrument with an auto sampler for the team’s personal use. In addition, he
served as a consultant regarding the chemistry of the system.
Daryl Gisch (Dow Chemical)
-Daryl located a sample of Dow BD10 Dry ion exchange resin and donated it to the team.
36
Rich Huisman
-Rich Huisman played a significant role in ordering materials for the team, specifically, the FAME
standard and the methanol. He saved the team a substantial amount of money through his orders. In
addition, he helped locate various compounds to be used for the HPLC analysis.
Glenn Remelts
-Glen Remelts helped the team in the beginning of the year with initial research. He showed the
team the vast resources the Hekman Library has to offer, as well as purchased important research
articles for the team.
Chuck Holwerda
-Helped with locating supplies for the control system.
Mississippi Lime
With the help of local representative Greg Wicklund, Mississippi Lime generously donated a 50 lbs
sample bag of high grade pulverized calcium oxide to be used as catalyst in the prototype reactor.
Eric Bouwkamp
Eric, a fellow Calvin engineer of the electrical concentration, selflessly helped The Diesel Crew with
many tasks involving the electrical control system components.
37
12 References
March 2007. Glycerin Traders. October 2014.
<http://www.glycerintraders.com/ASTM%206751%20spec.pdf>.
National Biodiesel Board. "The Biodiesel Standard (ASTM D 6751)." 2007. Biodiesel.
<www.biodiesel.org/resources/fuelfactsheets/standards_and_warranties.shtm>.
Advanced Organic Materials. "Fatty Acid Methy Ester MSDS." 2013. AOMSA.
Agency, U.S. Environmental Protection. A Comprehensive Analysis of Biodiesel Impacts on Exhaust
Emissions. October 2002.
Alovert, Maria. "The 3-27 Conversion Test." 2013. Make Biodiesel. November 2013.
Biodiesel Basics. 2013. November 2013.
Blanco, Sebastian. "Autobloggreen." June 2007. November 2013.
Borghi, Daniela de Feitas. "Thermochemical properties estimation for biodiesel related mixtures." n.d.
Engineering optimization. Web. April 2014.
Brevard BioDiesel. 2013. April 2014. <http://www.brevardbiodiesel.org/viscosity.html>.
Dewey, Charlsie. Metro Grand Rapids population passes 1 million. Grand Rapids, March 2013. Article.
DOW Chemical Company. Rohm and Haas. 2012. Novemeber 2013.
European Committee for Standardization. "Biofuel Specifications." 2004. Biofuel Testing.
<www.biofueltesting.com/specifications.asp>.
Haas, Rohm. Amberlite BD 10Dry Users Guide. France, 2008. User's Guide.
Kotrba, Ron. "The Many Faces of Distillation." Biodiesel Magazine 12 March 2013. Web.
Mazubert, Alex, Martine Poux and Joelle Aubin. Intensified processes for FAME prodcution from waste
cooking oil: A technological review. July 2013. PDF.
McNichols Industrial & Architectural Whole Product Solutions. 2010. December 2013.
<http://www.mcnichols.com/products/wire-mesh/>.
Motasemi, F. and F.N. Ani. "A review on microwave-assisted production of biodiesel." Renewable and
Sustainable Energy Reviews (2012): 4719-4733. PDF Document.
Murphy, Kellyann. Analysis of Biodiesel Quality Using Reversed Phase High-Performance Liquid
Chromatography. Senior Thesis. Claremont, California: Pomona College, 2012.
Perry, Robert, Don W. Green and James O. Maloney, Perry's Chemical Engineers' Handbook. 7th.
McGraw-Hill, 1997.
Refaat, A. A. "Biodiesel production using solid metal oxide catalysts." International Journal of
Environmental Science Technology (Winter 2011): 203-221. PDF.
Refaat, A. "Biodiesel Production Using Solid Metal Oxide Catalysts." International Journal of
Environmenal Science Technology (2011). Journal.
Rinnova. Final Report. Senior Design Report. Calvin College. Grand Rapids, MI: Harbert, Joshua; Ocier,
Christian; Kenyon, Mitch; Thielke, Fred; Alao, Adebo, 2008. PDF.
<http://www.calvin.edu/academic/engineering/senior-design/SeniorDesign0708/Team11/downloads.html>.
Samohon. "How to make an everlasting PTFE gasket." 8 October 2011. homedistiller. April 2014.
Science Lab. "Material Safety Data Sheet Listing." Dec 2013. Science Lab. Dec 2013.
<www.sciencelab.com/msdslist.php>.
38
Science Lab, Inc. Material Safety Data Sheet Potassium hydroxide MSDS. Houston: Scuebcelab.com, Inc.,
2013. MSDS.
Suwannakarn, Kaewta. "Biodiesel Production from High Free Fatty Acid Content Feedstocks." PhD
Dissertation. 2008.
Top-Notch Technology in Production of Oils and Fats. n.d. 2014.
<http://www.chempro.in/fattyacid.htm>.
U.S. Energy information Administration. December 2013. November 2013.
U.S. Energy Information Administration AEO2013 Early Release Overview. 5 December 2013. December
2013.
Vera, C. Production of biodiesel by a two-step supercritical reaction process with adsorption refining.
2010. PFD.
Weaver, Jennifer. Biodiesel Industry Overview and Technical Update. July 2013. Powerpoint.
Yang, Fangxia, Hanna A Milford and Runcang Sun. "Value-added uses for crude glycerol-a byproduct of
biodiesel production." Biotechnology for Biofuels (2012).
39
Appendices
Appendix A. Calcium Oxide Catalyst Details ............................................................................................. III
Appendix B. Solubility Testing................................................................................................................... IV
Appendix C. HPLC Summary ...................................................................................................................... V
C-1. Background ......................................................................................................................................... V
C-2. Method Development ...................................................................................................................... VII
C-3. Calibration Curves............................................................................................................................ VIII
Appendix D. LabVIEW Block Diagram ..................................................................................................... XIV
Appendix E. Expenses and Donations ..................................................................................................... XVI
Appendix F. Experimental Summaries .................................................................................................. XVIII
F-1. Fine Filter and WCO Temp Experiment ......................................................................................... XVIII
F-2. Acrylic Thermal and Chemical Degradation Testing ........................................................................ XIX
F-3. Batch Reaction Testing...................................................................................................................... XX
F-4. Microwave Batch Reactor Testing .................................................................................................. XXII
F-5. Microwave Hotspot Detection ....................................................................................................... XXIII
F-6. Acid Number Testing......................................................................................................................XXVI
F-7. Phase Region Testing ...................................................................................................................XXVIII
F-8. Settling Tank Volume Test ............................................................................................................. XXIX
Appendix G. ASTM Specifications for B-100 ......................................................................................... XXXI
Appendix H. Redesign of Subsystems .................................................................................................. XXXII
H-1. Dewatering System ...................................................................................................................... XXXII
Appendix I. 3-D Printed Parts..............................................................................................................XXXIV
I-1. Sprayer Valve for Dewatering Unit ...............................................................................................XXXIV
I-2. MeOH Column Distributer .............................................................................................................XXXV
I-3. Bottom Cap for Polishing Column ................................................................................................XXXVI
Appendix J. Schematic Drawings .......................................................................................................XXXVII
J-1. Dewatering Schematic.................................................................................................................XXXVII
J-2. MeOH Recovery Schematic ........................................................................................................XXXVIII
J-3. Schematic for Column Train ......................................................................................................... XXXIX
J-4. Static Inline Mixer Dimensions .......................................................................................................... XL
Appendix K. Calculations......................................................................................................................... XLI
K-1. Dewatering Calculations .................................................................................................................. XLI
K-2. Pressure Drop Across Packed Bed in Polishing Column ................................................................. XLII
K-3. MeOH Recovery Calculations ........................................................................................................ XLIII
K-4. PFR Flow Rate Estimate (95% Conversion) .................................................................................... XLIV
K-5. Microwave Power Implications ...................................................................................................... XLV
K-6. PFR Linear Velocity & PFR Volume ................................................................................................. XLV
K-7. Project Power Requirements & Added Energy Content/Cost ....................................................... XLVI
Appendix L. Pictures of System ............................................................................................................ XLVII
L-1. Baffles in CSTR ............................................................................................................................... XLVII
L-2. MeOH Recovery Unit ................................................................................................................... XLVIII
L-3. Density Separator........................................................................................................................... XLIX
L-4. Polishing Column................................................................................................................................. L
L-5. Control System ................................................................................................................................... LI
L-6. Overall System .................................................................................................................................. LII
I
Appendix A. Reaction Research Summary
Table A-1 Intensified Reactor Summary (Mazubert, Poux and Aubin)
OBR
Motionless
Inline
Reactors
ReactorSeparator
Medium
Low
Medium
EasyPurchased
Medium
8-1.6kW
8-1.6kW
Low
Low
Medium
Easy
Easy
Easy
Easy
>97%
>97%
99%
10 mins
99-99.8%
.17.66mins
0.5mins
0.5mins
30-40min
96-99%
17.519mins
ambient
60C
60C
~60C
60C
40-50C
ambient
Yes,
removal of
FFAs
Yes,
washing of
catalyst
ambient
Yes, removal
of FFAs
ambient
Yes,
removal
of FFAs
ambient
Yes,
removal
of FFAs
ambient
Yes,
removal
of FFAs
ambient
Yes,
removal of
FFA
ambient
Yes,
removal of
FFA
Yes, washing
of catalyst
No
No
No
No
No
yes (KOH)
yes(reduces
particle
size)
yes (KOH)
Yes
Yes
Yes
Yes
Yes
yes(reduces
particle size)
Yes
>50L/hr?
Medium
(external
heating)
V. Short
Reaction
Time
Yes
4.5-432
L/h
High
(internal
heating)
Low
Reaction
Time
Yes
0.126-3.12
L/hr
Not Tested
50-150 L/hr
Medium
(external
heating)
V. Short
Reaction
Time
Yes
4.5-432
L/h
High
(internal
heating)
Low
Reaction
Time
Medium
(external)
Medium
(external)
Low Energy
Input
Low Energy
Input
Ambient
Temps.
Low
Volumetric
Rate
Ambient
Temps.
A Minimum
Flow Rate
Exists
High Flow
Rate
Difficult
to Scale
Up
High Flow
Rate
Difficult
to Scale
Up
Requires
Specialized
Pump
Solids May
Be A
Problem
Microreactors
Type of Reactor
Specific Reactor
Type
Cost
Construction
Difficulty
Operation Costs
Operation
Difficulty
Typical
Conversion % to
FAME
Typical Reaction
Time
Operating
Temperature
Operating
Pressure
Pretreatment of
WCO Required
Treatment of
Product
Required
Requires
Catalyst (y/n)
Compatible with
Solid Metal
Catalyst
Typical Flow
Rates
Heat Transfer
Reactor specific
Advantages:
Reactor specific
Disadvantages:
Cavitation Reactors
Standard Tube
Microreactor
High for
required flow
rates
Acoustical
Cavitation
Hydrodynam
ic Cavitation
High
High
EasyPurchased
Low (only
pumps
required)
EasyPurchased
High (1000
watts)
EasyPurchased
Mediumreq. energy
input
Easy
Easy
98- 99.9%
Microwave Reactors
CSTR
Low for
Low
Volume
PFR
Low for
Low
Volume
Medium
High (91.1kW)
Easy
80-99%
95.00%
0.5-6 mins
Methanol
Reflux Temp
(60-65°C)
0.5 mins
ambient
Yes, removal
of FFAs
Yes, washing
of catalyst
yes (liquid
homogenous)
No
10-200 mL/hr
High/ External
Source
Short Reaction
Time
Easy postreactor
separation
Low Flow rates
(10-200 mL)
Batch
Low for
Low
Volume
Easy for
Low
Volume
0 L/h
High
(internal
heating)
Low
Reaction
Time
Helps
Break
Emulsions
V. Difficult
to Scale
Up
II
Oscillatory
Baffled
Reactors
72L/hr
Appendix B. Calcium Oxide Catalyst Details
This section describes in brief the theory and chemistry of CaO in the reaction to convert WCO to
BD. As CaO mixes with the methanol, a small amount of calcium methoxide, Ca(OCH3)2, forms which acts
as an initiating reagent for transesterification. CaO also reacts with glycerol in small amounts to form a
calcium-glycerol complex that may function as the main catalyst. The calcium-glycerol complex is soluble
in FAME resulting in leaching of the CaO, a drawback to its usefulness as a catalyst. Fortunately, this
complex can be removed by the anion-exchange resin that the team implemented into the design. The
conversion percentages of WCO to FAME at the chosen reaction conditions of 60°C and atmospheric
pressure can be as high as 97% depending on catalyst pretreatment. Pretreatment involves the thermal
treatment (calcination) of the CaO at temperatures ranging from 500-900°C to remove H2O and CO2
from basic sites on the catalyst. Calcination is improved when the catalyst is kept in an inert
environment (under nitrogen or helium) to avoid exposure to H2O and CO2. The possibility that a
pretreatment of CaO is required to achieve sufficient conversion and the necessity of storing the catalyst
in a water free environment are both negatives to this catalyst choice. The team chose not to explore
the calcination of the catalyst, rather we made sure to store the catalyst with minimal exposure to air.
Another consideration to be made with CaO is its resistance to poisoning by water and FFA. Research
revealed that CaO catalytic activity can be promoted by a small presence of water, up to 2.8 wt% of the
total WCO. Higher percentages of water result in deactivation of basic sites, severely limiting FAME
conversion, as well as hydrolysis of the FAME product into FFA. CaO effectiveness for FAME conversion
decreases with the concentration of FFAs present. At elevated levels of FFAs, soap production also
becomes a major concern (A. Refaat).
Obtaining catalyst was not as easy a task as the team had thought originally. Rich Huisman, the
chemistry department lab manager, graciously gave the team 200-300 grams of CaO for initial lab
testing. However, this amount was not sufficient for running the prototype reactor. The team
investigated many local supply companies to no avail. After some research, the team discovered that
CaO is can be produced from CaOH. This process requires very hot temperatures to break the covalent
bonds of OH- and Ca+. Professor Tatko allowed the team to use the vacuum oven located in the physical
chemistry lab. Operating at a temperature of 300 ℃ and a vacuum of 0.1 atm, the team did not
successfully remove any water. Secondly, the team attempted to use Bunsen burners to reach even
higher temperatures. However, the team again was unsuccessful in sintering off the water. Towards the
end of the semester, the team made contact with a cement supply company in Missouri, Mississippi
Lime. The regional sales representative promised to donate a fifty pound bag for our use. However as of
senior design night, a month after the initial contact, the team had still not received the catalyst to
thoroughly test the reactor system.
III
Appendix C. Solubility Testing
Due to initial issues with the HPLC, the team desired a simpler method to analyze samples for
conversion. The team came across the Warnquist 3/27 test. This test utilizes the fact that triglycerides
are almost completely insoluble in MeOH and FAME is soluble in MeOH at room temperature. The test
procedure is to put exactly three mL of biodiesel product in twenty-seven mL of MeOH at room
temperature. After agitation, if the solution forms two phases, then the conversion was too low
(Alovert). The team decided to modify this test to give a rough estimate of conversion.
The team obtained two conical vials with graduations to use for the test, one plastic, one glass. A
team member calibrated each of these vials for use in the solubility test by adding WCO, massing the
amount of WCO added, adding a set amount of MeOH (11.0mL for glass, 13.5mL MeOH for plastic),
shaking for one minute, centrifuging for one minute at 4500 RPM, and measuring the volume of the
lower phase. To test samples, this procedure was repeated, measuring the mass of slightly over one mL
biodiesel product sample into the vial rather than WCO. The two following calibration curves were used.
Figure C-1 Calibration Curve for 3/27 Test using a Glass Vial
Figure C-2 Calibration Curve for 3/27 Test using Plastic Vial
IV
The solubility test is accurate if you assume that FAME does not increase the solubility of
triglycerides in biodiesel, mono and diglycerides are just as insoluble in MeOH as triglycerides are, and
there are no other materials in the sample. These assumptions cannot be fully made, so the solubility
test has limited accuracy, but the test was accurate enough for the team’s purposes.
Appendix D. HPLC Summary
D-1. Background
To determine how well the reactor system was working, the team needed an analytical method
to determine the conversion reached. One chosen technique was HPLC with UV-Vis. HPLC is a separation
technique that when partnered with UV-Vis can also identify, and quantify components of a mixture
through the use of standards and calibration curves.
Due to the variety of compounds present in WCO, the selection of standards was chosen to
represent the entire range of possibilities. Present in the oil are tri-, di-, and monoglycerides, and free
fatty acids. In addition to the WCO, different FAMEs will be present in the product. However, only those
compounds that have some degree of unsaturation are detectable by UV-Vis and therefore quantifiable.
Calvin Dining services graciously provided the Diesel crew with WCO. The Dining services uses soybean
oil from Zoye®. The composition of soybean oil is shown in Table D-1 (Top-Notch Technology in
Production of Oils and Fats).
Table D-1 Summary of Soybean oil composition
Compound
Palmitic Acid
Stearic Acid
Oleic Acid
Linolenic Acid
Linoleic Acid
Type
C16:0*
C17:0
C17:1
C17:3
C17:2
Wt %
7-11
2.0-6.0
22.0-34.0
5.0-11.0
43.0-56.0
* The convention for long chain fatty acid is C#:# indicating the total number of carbons in the compound first number, and the degree of unsaturation by the
second number.
The Calvin Chemistry Department allowed the team to borrow a Zorbax Rx-C8 4.6 mm X 25 cm
PN. 880967.907 reverse phase column. Communicating with Rich Huisman and Professor Tatko, the
team acquired all of the compounds necessary for standards except for the methyl esters; the team
chose to use mono-olein, and two fatty acid compounds abundant in soybean oil, linoleic acid and oleic
acid. The team decided to purchase the FAME standards, choosing a Fatty Acid Methyl Ester Mix (189171AMP) from Sigma Aldrich which is a mixture of FAME (Table D-2).
V
Table D-2 Summary of Compounds in Fatty Acid Methyl Ester Mix
Compound
Methyl Arachidate
Methyl Behenate
Methyl Elaidate
Methyl Linoleate
Methyl Linolelaidate
Methyl Linolenate
Methyl Myristate
Methyl Oleate
Methyl Palmitate
Methyl Stearate
Type
C20:0*
C22:0
C19:1
C18:2
C19:2
C18:3
C14:0
C18:1
C17:0
C18:0
Wt. %
2.0
2.0
10.0
34.0
2.0
5.0
4.0
25.0
10.0
6.0
* The convention for Long chain fatty acid methyl esters is C#:# indicating the total number of carbons in the compound first, and the degree of unsaturation by the
second number. It should be noted that the difference in the numbering of the fatty acids and the methyl esters is always one carbon as a methyl group replaces
the acid group in the reaction chemistry.
The Fatty Acid mix from Sigma Aldrich is a good representation of the composition of the biodiesel
product, having high concentrations of methyl oleate and methyl linoleate, which will result from a high
soybean concentration of oleic acid and linoleic acid. The acid compounds listed in Table D-1,
correspond to their glyceride forms, with only a small percentage of the oil composition being the free
fatty acid form.
To accurately quantify the compounds in the samples, calibration curves must be constructed.
However, first the retention times must be identified for each compound. The retention times are
affected by solvent flow rate, the polarity of the solvent, and the temperature of the column. The team
used reverse phase chromatography meaning that the column is nonpolar and the solvent is polar.
Increasing the polarity of the solvent (increasing the amount of water) results in longer retention times.
The team optimized the solvent flow and composition to produce peaks with good resolution at short
enough retention times so as to reduce the amount of solvent used. The team started with a gradient
flow based on the work done from a group from Pomona College. The conditions or method were
solvent A: 85% Acetonitrile, 15% Type I water (0.1% TFA), Solvent B Acetone (0.1%T TFA), a flow rate of
0.7 mL/min, injections of 5 μL, a column temperature of 50 ℃, and a wavelength of 210 nm (Murphy).
The Pomona grouped used a gradient solvent, meaning that the amount of solvent B in the system is
increased during the run time (Table D-3).
Table D-3 Summary of Pomona Group Gradient Elution
Time (min)
0
10
20
40
50
60
%Solvent A
100
100
70
20
0
0
VI
%Solvent B
100
100
30
80
100
100
D-2.
Method Development
The team had some issues with the Pomona method; the methanol absorbed at a wavelength of
210 nm. However, all of the compounds eluted before methanol was introduced into the column. The
team changed the method to a non-gradient solvent, using only acetonitrile and water at a constant
composition. Varying the flow rates, (0.7 to 1.1 mL/min) and the concentration of water in the solvent
(10-40%), the team established the method as 75% Acetonitrile, 25% Type I Water (0.1%TFA), a flow
rate of 1.0 mL/ min, injections of 5 μL, a column temperature of 50 ℃, and a wavelength of 210 nm. The
team established accurate retention times once the method was finalized (Table D-4).
Table D-4 Summary of Retention Times for Standards
Compound
Retention Time (min)
THF
3.3 ± 0.1
Linoleic Acid
5.6 ± 0.1
Monoglycerine
6.6 ± 0.2
Oleic Acid
8.1 ± 0.2
Methyl Linolenate
11.5 ± 0.3
Methyl Linolate
14.9 ± 0.3
Methyl Oleate
20.4 ± 0.4
The team established the retention times of the FAME mixture by the order of retention times of
the Pomona group. In addition, the higher degree of unsaturation in a fat results in an increase in
polarity, and shorter retention time in reverse phase HPLC (the affinity for the solvent is increased with
increasing polarity of the solutes). This fact confirms the retention times determined by the group. An
example of the retention times with peak resolution in Figure D-1.
Figure D-1 Example of HPLC Retention Peaks
VII
D-3. Calibration Curves
Calibration curves are used to determine the amount of analyte present in the sample. According to
Beer’s law, the absorbance of the analyte is proportional to the concentration of the analyte in solution.
Calibration curves are constructed by making a range of standards in varying concentrations, and
integrating their respective peaks. A plot of the integration area vs. concentration should be linear
according to Beer’s law, and through this linear fit, the concentration of an unknown is determined by
the absorbance level detected. To help determine how much of the triglyceride feed is converted to
FAME, the team created a calibration curve of the mono-olein, linoleic and oleic acid, and three of the
FAMEs in the mixture. The team used a range of 0.0006 to 0.6 mg of analyte injected into the column.
The curve’s regression statistics and raw calibration data is included below.
Monoolein
50,000
y = 78834x + 3501.3
R² = 0.9983
45,000
40,000
Absorbance
35,000
30,000
25,000
20,000
15,000
10,000
5,000
0
0
0.1
0.2
0.3
0.4
mg of analyte
Figure D-2 Calibration Curve for Monoolein at for HPLC Method
VIII
0.5
0.6
Oleic Acid
8000
y = 11242x + 576.02
R² = 0.9724
7000
Absorbance
6000
5000
4000
3000
2000
1000
0
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.6
0.7
mg of analyte
Figure D-3 Calibration Curve for Oleic Acid at for HPLC Method
Linoleic Acid
16000
y = 23674x + 329.42
R² = 0.991
14000
Absorbance
12000
10000
8000
6000
4000
2000
0
0
0.1
0.2
0.3
0.4
0.5
mg of analyte
Figure D-4 Calibration Curve for Linoleic Acid at for HPLC Method
IX
Methyl Linolate
12000
10000
y = 427101x + 56.471
R² = 0.9995
6000
4000
2000
0
0.000
0.005
0.010
0.015
0.020
0.025
mg of analyte
Figure D-5 Calibration Curve for Methyl Linolate at for HPLC Method
Methyl Oleate
4500
y = 47528x - 22.344
R² = 0.9993
4000
3500
3000
Absorbance
Absorbance
8000
2500
2000
1500
1000
500
0
0.00
0.02
0.04
0.06
0.08
mg of analyte
Figure D-6 Calibration Curve for Methyl Oleate at for HPLC Method
X
0.10
Methyl Linolenate
25000
y = 1,107,331.85x + 98.20
R² = 1.00
Absorbance
20000
15000
10000
5000
0
0.000 0.002 0.004 0.006 0.008 0.010 0.012 0.014 0.016 0.018 0.020
mg of analyte
Figure D-7 Calibration Curve for Methyl Linolenate at for HPLC Method
Table D-5 Summary of HPLC Calibration Data
Monoolein
Amount (mg) Integration (AU)
0.0525
0.0625
0.105
0.125
0.525
0.625
------Methyl Linolate
Amount (mg) Integration (AU)
0.01187
5291.1
0.02373
10112.6
--0.00028
141.4
0.00057
268.9
0.00285
1254
Oleic Acid
Amount (mg)
Integration (AU)
0.0625
921.5
0.125
2139.6
0.625
7599.1
0.000625
190.343
0.00125
346.1
0.00625
1485.3
Methyl Oleate
Amount (mg)
Integration (AU)
0.00873
427.3
0.01745
843.4
0.08725
4115.5
-------
XI
Linoleic Acid
Amount (mg) Integration (AU)
0.0625
1899.
0.125
4365.0
0.625
1490
0.000848
0.0
0.001695
85.
0.008475
215.52
Methyl Linolenate
Amount (mg) Integration (AU)
0.00174
2110.
0.003490
4158.
0.017450
19375.
0.000042
53.
0.000084
10
0.000419
512.
Finally as an example of absorbance of species at low and high concentrations, the following two spectra
are shown for Reactions B and F with conversions of 7.7% and 72.7% respectively. The data for these
experiments can be viewed in section G-3 Batch Reaction Testing.
Table D-6 Summary of Statistical Analysis of Calibration Curves
Compound
Monoolein
Oleic Acid
Linoleic Acid
Methyl
Linolate
Methyl Oleate
Methyl
Linolenate
Slope
78834.14
11242.45
22576.46
y-intercept
3501.30
576.02
890.75
"+- slope"
3273.54
947.65
944.79
b +1016.74
247.78
247.03
R^2
0.9983
0.9724
0.9930
Standard Error Y
1198.93
517.28
515.72
311260.40
882.62
11542.01
573.10
0.9945
1190.23
47527.85
-22.34
616.73
22.52
0.9993
46.76
1107331.85
98.20
8432.68
61.58
0.9998
127.88
Figure D-8 Spectra for Batch Experiment B, conversion of 7.7%
XII
Figure D-9 Spectra of Batch Experiment F, conversion of 72.7%
XIII
Appendix E. LabVIEW Block Diagram
Figure E-1 Part 1 of LabVIEW Block Diagram
XIV
Figure E-2 Part 2 of LabVIEW Block Diagram
XV
Appendix F. Expenses and Donations
The team’s expenditures for the project are shown below
Table F-1 Itemized Expenditures of Teams 1
Item
Amount
PFD Printout (Consultant)
1
5 Cases of Methanol
1
FAME Std.
1
Microwave
1
Grommets
1
Tubing
1
15 gal. HDPE Barrels
8
Antifreeze for Rotavaps
1
Electric Heating Element (Dewaterer)
1
Wire Mesh Cloth
3
Stainless Steel Rod
1
DeWaterer Supplies (Godwin)
1
static mixers
1
Plastic Bulk Head
1
Reducing Couple
1
Grainger Heating Element
2
Calcium Hydroxide 11 lbs
1
Clear PVC Cap 1-1/2"
3
Pipe Insulation
1
Resing Column O-Ring
1
Thermocouple Order 1
4
Thermocouple Order 2
4
Relay Order 1
3
Cable Finger Ducting
1
Monoprice Wire (250ft)
1
Monoprice Hook&Loop Ties
1
Cole-Palmer Various Tubing
1
Static Inline Mixers
1
MSC Supply Various Tubing
1
10ga Extension Cord (100')
1
Extension Cord Male Ends
3
Extension Cord Female End
4
20amp Male End Plug
1
US. Plastics Polishing Column
1
Lowe's Settling Tank Supplies
1
Zoro Tools Settling Tank Supplies 1
Clear PVC Cap 1-1/2"
2
All 3D Printing
1
1/2 to 3/8 male adapter Godwins 1
Ethylene Glycol
1
Red Rubber Packing
2
Lowes PTFE tape, Cap for Catalyst feed
1
Nylon Washers Lowes
1
Dyer Supplies,
1
Zipties, weather stripping
1
Stroke Rate Controller
1
Microwave Fuses + HV Diode
1
Price
0.35
100
100
16
2.12
1.06
4
13.89
11.78
4.55
3.13
72.73
8.75
10.89
19.23
12.7
64.41
14.64
1.26
0.98
5.28
5.98
10.69
23.98
25.11
11.68
285.85
9.9
53.77
101
6.24
4.68
14.97
18.36
39.85
57.71
14.64
147.67
1.96
9.97
1.97
8.7
3.44
9.99
7.26
5
12
Shipping
0
0
0
0
0
0
0
0
5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
28.22
0
10.4
0
0
0
0
0
0
14.94
0
19.59
7.19
0
0
0
0
0
0
0
0
15.03
0
XVI
Total Cost (USD)
$
0.35
$
100.00
$
100.00
$
16.00
$
2.12
$
1.06
$
32.00
$
13.89
$
16.78
$
13.65
$
3.13
$
72.73
$
8.75
$
10.89
$
19.23
$
25.40
$
64.41
$
43.92
$
1.26
$
0.98
$
21.12
$
23.92
$
32.07
$
23.98
$
53.33
$
11.68
$
296.25
$
9.90
$
53.77
$
101.00
$
18.72
$
18.72
$
14.97
$
33.30
$
39.85
$
77.30
$
36.47
$
147.67
$
1.96
$
9.97
$
3.94
$
8.70
$
3.44
$
9.99
$
7.26
$
20.03
$
12.00
Running Total Date
$
0.35
$
100.35
$
200.35
$
216.35 not yet
$
218.47
$
219.53
$
251.53
$
265.42
$
282.20
$
295.85
$
298.98
$
371.71
$
380.46
$
391.35
$
410.58
$
435.98
$
500.39
$
544.31
$
545.57
$
546.55
$
567.67
$
591.59
$
623.66
$
647.64
$
700.97
$
712.65
$
1,008.90
$
1,018.80
$
1,072.57
$
1,173.57
$
1,192.29
$
1,211.01
$
1,225.98
$
1,259.28
$
1,299.13
$
1,376.43
$
1,412.90
$
1,560.57
$
1,562.53
$
1,572.50
$
1,576.44
$
1,585.14
$
1,588.58
$
1,598.57
$
1,605.83
$
1,625.86
$
1,637.86
21-Nov-13
5-Dec-13
3-Dec-13
28-Feb-14
28-Feb-14
6-Mar-14
10-Mar-14
18-Mar-14
27-Mar-14
27-Mar-14
17-Mar-14
14-Mar-14
15-Apr-14
15-Apr-14
12-Apr-14
9-Apr-14
23-Apr-14
23-Apr-14
23-Apr-14
23-Apr-14
23-Apr-14
23-Apr-14
23-Apr-14
23-Apr-14
24-Apr-14
23-Apr-14
16-Apr-14
24-Apr-14
24-Apr-14
24-Apr-14
24-Apr-14
24-Apr-14
25-Apr-14
25-Apr-14
25-Apr-14
25-Apr-14
26-Apr-14
9-May-14
9-May-14
29-Apr-14
1-May-14
4-May-14
18-Apr-14
29-Apr-14
11-Mar-14
18-Mar-14
The team was very fortunate in the equipment it received via donation and borrowing from the
engineering department, these costs are summarized below.
Table F-2 Itemized Donations and Borrowed Equipment Value
Item
Amount
Amana commercial Microwave
Polishing Column Resin
Vacuum Pump
Metal Frame
CSTR, condenser, mixer, glassware
LabVIEW FieldPoint Modules
LabVIEW Software
Temperature Bath Units
Methanol Evaporation Column
4 FMI Metering Pumps
3 FMI Pump Controllers
Asus Windows XP Computer
Cartridge Filter
Pressure Transducers
1
1
1
1
1
1
1
3
1
4
3
1
1
5
Estimated Price
$
1,200.00
$
160.00
$
1,850.00
$
300.00
$
2,500.00
$
3,000.00
$
2,000.00
$
1,200.00
$
250.00
$
546.00
$
312.00
$
250.00
$
80.00
$
224.00
Total Value
$
1,200.00
$
160.00
$
1,850.00
$
300.00
$
2,500.00
$
3,000.00
$
2,000.00
$
3,600.00
$
250.00
$
2,184.00
$
936.00
$
250.00
$
80.00
$
1,120.00
XVII
Running Total
$
1,200.00
$
1,360.00
$
3,210.00
$
3,510.00
$
6,010.00
$
9,010.00
$
11,010.00
$
14,610.00
$
14,860.00
$
17,044.00
$
17,980.00
$
18,230.00
$
18,310.00
$
19,430.00
Source
Donated by subway
Dow
Calvin
Calvin/Pfizer
Calvin/Pfizer
Calvin/Pfizer
Calvin
Calvin/Pfizer
Calvin
Calvin/Pfizer
Calvin/Pfizer
Lakeshore Pharmacies
Calvin
Calvin/Pfizer
Appendix G. Experimental Summaries
G-1. Fine Filter and WCO Temp Experiment
WCO is fairly viscous at ambient temperature, thus the team investigated WCO flow through
fine filters at different temperatures.
Materials & Equipment:
 WCO (Soy oil) from Calvin College Dining Services’ WCO pit
 Meijer brand coffee filters
 Two 25mL graduated cylinders
 Stirrer/Hot plate with beaker and stir bar
 Thermometer and Stopwatch
Procedure:
A volume of 20.0 mL of WCO at one of several different temperatures was poured on a coffee
filter over a graduated cylinder, and the volume of flow through was measured after 2.00 minutes and
checked for particulate. New coffee filters were used for each trial. This procedure was then repeated
using two coffee filters stacked on top of each other rather than one.
Results and Discussion:
Table G-1 Results of Fine Filter Temperature Experiment
Number of Filters
Temp (°C) Time (s) Volume (mL) Particulate in Pure
20
120
2
No Particles
30
120
6
No Particles
1
40
120
6.1
No Particles
60
120
12
No Particles
95
120
11
No Particles
30
120
3
No Particles
40
120
3
No Particles
2
60
120
6.8
No Particles
95
120
6
No Particles
The data shows, for both one and two filters, that increasing the temperature of the WCO
dramatically increases the ease of flow through the filters up to 60°C where the flow rate levels off. The
data also shows that the flow is inhibited by a factor of two when two filters are used rather than one,
and no particulate is found in the flow through at any temperature or number of filters in the ranges
tested.
Conclusion:
Testing flow of WCO through fine filters has shown that to increase flow through the filters, oil
doesn’t need to be heated to more than 60°C. The experiment has further shown that if coffee filters
were to be implemented as a fine filter, one coffee filter will achieve the same separation as two coffee
filters with half the inhibition to the flow. This trend might be applicable to all filters that separate by
particle size. The only thing the team would do differently if repeating the experiment is use volumes of
WCO greater than 20mL. This experiment was useful because it showed that heating the WCO to 60°C
will allow for better flow.
XVIII
G-2. Acrylic Thermal and Chemical Degradation Testing
The acrylic compound used in the 3-D printer has a maximum operating temperature of
approximately 90 ℃. Additionally, many plastics do not hold up to WCO or biodiesel, thus the team saw
it prudent to check the material for thermal or chemical degradation at temperatures above what the
system is run at.
Materials and Equipment:
 Spare acrylic part
 WCO
 Heating mantel/stir plate
 Magnetic stir bar
 Thermometer
 Mass balance
 250 mL beaker
 stopwatch
Procedure:
The team member recorded the mass of the dry acrylic part. Next he prepared an oil bath, placing
enough oil in the beaker to fully cover the part, and turning on the heat. The team member placed the
part in the oil at 110 ℃ after inserting the magnetic stir bar. At various times the team member
removed, washed thoroughly with soap and water, dried and weighed the part.
Results:
Table G-2 Summary of Results from Acrylic Testing
Time (hours)
Start:
1.0
2.0
3.0
4.0
Mass (grams)
17.10
17.10
17.10
17.09
17.09
Conclusion:
The acrylic part showed no signs of chemical or thermal degradation. The mass of the part changed
by 0.01 grams in 240 minutes of testing while exposed to temperatures above the operating
temeprature of our system. Additionally, the part did not lose its rigidity even at elevated temperatures.
The part tested was thin and wide, indicating that the thicker part designs for the spray valve, methanol
distillation column cap, and polishing column cap will stand up to the operating conditions.
XIX
G-3. Batch Reaction Testing
There is limited information available about the reaction of triglycerides to FAME using CaO as a
catalyst, so the team did reaction testing to determine if the required conversion could be achieved in a
reasonable amount of time and what would be the best ratios of MeOH and CaO to WCO.
Materials and Equipment:
 J-KEM Scientific temperature control unit with thermocouple
 Heating mantle
 Three-neck 500mL round-bottom flask
 Condenser
 Agitator
 MeOH
 Filtered, dewatered WCO
 CaO powder (obtained from Rich Huisman)
 Buchner flask and filter funnel
 Rotary evaporator
Figure G-1 Batch Reaction Setup
XX
Procedure:
First, the desired amounts of MeOH and WCO were measured using graduated cylinders and
poured into the round-bottom flask, keeping the total volume between 300 and 420 mL for each
reaction. The round-bottom flask was then placed on the heating mantle and outfitted with a
condenser, agitator, and sealed thermocouple. The thermocouple and agitator were sealed. The heat
control was set to 60°C, and the heat and agitation were turned on. Once the temperature of the
mixture stabilized at 60°C, the desired amount of catalyst was added through the thermocouple neck,
and the thermocouple was resealed and time recorded. After the desired time had passed, the time was
recorded, and the round-bottom flask was placed in an ice bath to quench the reaction.
After the reaction mixture was sufficiently cooled, vacuum filtration was used to separate out the
catalyst. Once all of the liquid product had flowed through, additional MeOH was added to the filter to
rinse out any FAME that was still adsorbed. The flow-through was transferred to a rotary evaporator,
which was run until all of the MeOH was evaporated. The glycerol settled to the bottom of the
remaining product, and the top fraction was analyzed via HPLC and solubility testing.
Results and Discussion:
The temperature control was able to keep the temperature within 5°C of 60°C, generally within 2°C.
First, a reaction was run for one hour with no catalyst, and no noticeable conversion occurred. This
validated the procedure, showing that no reaction would occur before the catalyst was added.
Some literature suggested that it might not be possible to achieve high conversion in a short
amount of time, so the team wanted to figure out how long it would take to reach >95% conversion. To
get this knowledge, a reaction was performed that deviated from the aforementioned procedure. The
catalyst was added before the desired temperature was reached, and the reaction was run for a total of
two hours and thirty four minutes. Solubility testing showed approximately 100% conversion, indicating
to the team that we could move forward with the CaO catalyst.
To determine what MeOH and catalyst ratios to use, the team conducted experiments keeping
MeOH ratio constant while varying catalyst ratio, then keeping catalyst ratio constant while varying
MeOH ratio. Some of the results are shown below.
Table G-3 Batch Reaction Testing Results
Sample
MeOH:WCO
g CaO: L
Conversion
wt% CaO
CaO (g)
Time (min)
Vol. WCO (mL)
Name
Vol. Ratio
WCO
A
1.1%
6
57
1.0%
3.39
60
60
B
7.7%
6
113
2.0%
6.79
64
60
C
46.8%
6
170
3.0%
10.18
61
60
D*
50.3%
6
283
5.0%
16.97
60
60
E
68.9%
2
283
11.4%
28.28
60
100
F
72.5%
4
283
6.9%
22.63
60
80
G
28.2%
8
283
3.9%
12.73
61
45
*Temperature was lower than 55°C for a significant portion of the reaction time, expected conversion is greater
Conclusion:
Results helped the team arrive at using 283g CaO per L WCO to attain high rates and lower the
amount of reactor volume needed. Additional reactions were desired, but the team decided on a
MeOH:WCO vol. ratio of 1:1, for energy and heat transfer reasons in the MeOH recovery system.
XXI
G-4. Microwave Batch Reactor Testing
Literature showed that using a microwave for heating increased the rate of reaction. The team
wanted to confirm that this was the case.
Materials and Equipment:
The materials and equipment for microwave batch testing were the same as for the standard batch
testing, except for the following:
 A microwave was used for heating instead of a mantel, thus no temperature control unit was
used
 A surface measuring thermocouple with a digital multi-meter was used
 A single necked round-bottom flask with a y-connection was used
Figure G-2 Microwave Batch Setup
Procedure:
To compare this test to the batch reaction with regular heating, a MeOH ratio of 6:1 was used and a
catalyst ratio of 113g CaO:1L WCO was used.
XXII
The MeOH and WCO were combined and heated on a mantel until 60°C was reached. The catalyst
was then added, and the flask was moved to the microwave and the agitator was turned on. The
microwave was controlled manually, and the microwave door was periodically opened so the
temperature could be measured by placing the thermocouple on the surface of the round-bottom flask.
After one hour, the flask was removed and the effluent was purified as described in the Batch
Reaction Testing section.
Results and Discussion:
It was difficult to control the temperature, as the sampling for temperature was very sporadic.
Furthermore, a lot of MeOH would vaporize and then condense when the microwave was on, so there
was much more refluxing in this experiment than the standard batch reactions. This likely means that
the temperature was closer to the normal boiling point of MeOH for much of the run (65°C).
The solubility test showed that the sample reached 39% conversion, whereas the batch reaction
with traditional heating at the same MeOH and catalyst ratios and time yielded only 7.7% conversion.
Conclusion:
Although there are some large sources of error in this experiment, the results clearly indicate that
there is an advantage to using a microwave for heating the reaction.
G-5. Microwave Hotspot Detection
Team One used temperature-sensitive thermal receipt paper to examine the Emerson microwave
used for batch microwave experiments for hotspots. The hot spots are presumably caused by nodes of
microwave density within the microwave cavity. We dampened and laid strips of the thermal receipt
paper on damp cardboard or plastic at several heights within the microwave and ran the microwave at
full power for runs of about 10-15 seconds until the paper began to darken.
Figure G-3 Microwave Node Detection (Low)
XXIII
.
Figure G-4 Microwave Node Detection (Middle)
XXIV
Figure G-5 Microwave Node Detection (Higher)
XXV
G-6. Acid Number Testing
The acid number is a very important piece of information regarding the purity of the biodiesel
product. The acid number is a measure of the amount of fatty acid in a product, or the mass in
milligrams of KOH required to neutralize one gram of the sample. The ASTM allows for an acid
number of 0.5, approximately 0.25 wt% fatty acid. If the number is higher this can lead to troubles
when using the fuel in an engine.
Materials and Equipment
 100 mL beaker
 Phenolphthalein pH indicator
 Standardized NaOH
 Burette
 Magnetic Stir Bar
 Stir plate
 THF as solvent
Procedure
A team member measured about three grams of product into the beaker. Enough THF was mixed in
to the beaker to fully dissolve the oil, typically 30 mL for three grams of product. The team member
added 5 drops of phenolphthalein indicator and titrated with the standardized NaOH. The solution
turned from a clear yellow, to a pale salmon color upon the equivalency point, and pink salmon
after the equivalency point, (Figure G-6, Figure G-7, and Figure G-8). The team performed the acid
number test on products before and after polishing with the Amberlite™ BD10Dry™ (Table G-4,
Table G-5).
Figure G-6 Dissolved Product in THF with pH Indicator
XXVI
Figure G-7 Dissolved product in THF at equivalency point, pale salmon color
Figure G-8 Dissolved product in THF after equivalency point, pink salmon color
XXVII
Results
Table G-4 Summary of Acid Number Results of Various Experimental Products
Sample
Experiment A
Experiment B
Experiment C
Experiment D
Experiment G
Microwave Rxn 2
WCO
Acid Number
0.36
0.58
0.58
0.52
0.64
0.85
1.44
Table G-5 Summary of Results of Acid Number Test after Polishing Samples
Sample
Experiment A
Experiment C
Experiment G
Microwave Rxn 2
Acid Number
0.27
0.47
0.35
0.46
Difference
-0.09
-0.11
-0.29
-0.39
The acid number is calculated according to
56.1
𝑊𝑜𝑖𝑙
Where Veq is the equivalency volume of the titrant, N is the molarity of the titrant, 56.1 is the
molecular weight of KOH, and Woil is the mass of the sample product, oil or biodiesel.
𝐴. 𝑁. = 𝑉𝑒𝑞 𝑁
Conclusion
The acid number test showed that the reaction reduced the fatty acid composition of the oil
significantly, indicating partial conversion of the free fatty acids to methyl esters. The WCO had an
acid number of 1.44, and the average acid number from unpolished product was 0.54. Polishing the
product resulted in average acid number decrease of 0.22, or 33% decrease in free fatty acid.
G-7. Phase Region Testing
The reactor effluent contains glycerol, FAME, and MeOH. These form one, two or three phases
depending on temperature and composition. The team needed to find out at what temperatures the
number of phases changed for compositions of interest.
Materials and Equipment:
 50mL Erlenmeyer flask
 Hot plate
 MeOH, FAME, Glycerol
 Thermometer
XXVIII
Procedure:
Erlenmeyer flask was filled with 15.0mL of MeOH and 15.0mL of FAME. The thermometer was put
in the flask and the temperature and an observation of the phases was recorded. The reaction was then
heated slowly until the mixture became one phase. The mixture was then allowed to cool, recording the
temperature and an observation of phase periodically, until the mixture formed two phases again. Then
another 15.0mL of MeOH was added to the mixture and the procedure was repeated.
Results and Discussion:
At the 2:1 MeOH vol. ratio, the mixture never reached one phase. There was always at least a slight
brown phase at the bottom of the Erlenmeyer flask.
Table G-6 Summary of Phase Region Test Results
1:1 MeOH:FAME Vol. Ratio
Temp. (°C)
Phase Observation
19.5
2 phases
29.4
1 phase
26.7
1 phase
23.7
1 phase
Solution becomes cloudy and second
22.7
phase starts to form
2:1 MeOH:FAME Vol. Ratio
Temp. (°C)
Phase Observation
19.5
2 phases
26.0
2 phases
44.2
Small second phase
60.0
Small second phase
The 15.0mL of FAME/glycerol mixture used was thought to be almost entirely FAME with some
glycerol, but later testing showed there was actually probably some triglycerides in the sample. This
would explain the results of this experiment as the triglycerides would dissolve in the 1:1 solution
because there was a lot of FAME to keep it in one phase, but the triglycerides formed a new phase when
the mixture became higher in MeOH.
Conclusion:
The reactor effluent should be all in liquid phase (other than the catalyst) if the temperature is
above 23°C and a 1:1 MeOH:WCO ratio is used for the reactor. This was helpful for determining that a
setting tank design would work, because the FAME will not settle to the bottom while the MeOH flows
to the next tank if there is only one liquid phase.
G-8. Settling Tank Volume Test
The team needed to know the wet volume of the settled catalyst in order to determine the settling
tank size and how much liquid would be held up in the tank with the settled catalyst.
Materials and Equipment:
 Thermometer
 MeOH and rxn H biodiesel product
 CaO powder
 25mL graduated cylinder
Procedure:
Temperature was measured, and 10.0mL of MeOH, 10.0mL of biodiesel product, and 2.834g of CaO
were combined in the graduated cylinder. This mixture was allowed to settle for fifteen minutes and
then the volume of the layers was recorded.
XXIX
Results:
The temperature was recorded as 20°C. The catalyst phase was 6.3mL. The biodiesel and WCO
phase came up to 11.9mL, and the FAME and MeOH phase came up to the 20.7mL mark.
Figure G-9 Settled Catalyst Distribution (20°C)
𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑜𝑓 𝑙𝑖𝑞𝑢𝑖𝑑 𝑖𝑛 𝑐𝑎𝑡𝑎𝑙𝑦𝑠𝑡 𝑙𝑎𝑦𝑒𝑟 = 100% ∗
20.0𝑚𝐿 − (20.7 − 6.3)𝑚𝐿
= 28%
20.0𝑚𝐿
Conclusion:
Allowing the catalyst to settle causes at least 28% of the liquid product to be held up with the solid.
XXX
Appendix H. ASTM Specifications for B-100
Table H-1 ASTM Specifications for B-100
(Glycerin Traders)
XXXI
Appendix I. Redesign of Subsystems
I-1. Dewatering System
The initial design (Figure I-1) placed the heating element at the outlet of the tank, just before the
pump. This location resulted in burning the coil out (Figure I-2).
Heating Element
Figure I-1 Initial DeWatering System Design
After careful investigation the team determined that when the oil reached a temperature near the
boiling point of water, 75 to 80 ℃, the pump began to cavitate due to the boiling of some of the water.
When cavitation occurs the pump is no longer able to push any oil through the system, and the heating
element does not have sufficient fluid flowing past to keep it cool, overheating as a result.
XXXII
Figure I-2 Burned Out Heating Element from Initial Dewatering Design
Re-evaluating the initial design, the team determined that the placement of the heating element
should go after the pump, see section K-1 Dewatering Schematic. In this way if any of the water
vaporizes due to the high energy output of the coil, it will be passed through to the valve and released
to the atmosphere.
XXXIII
Appendix J. 3-D Printed Parts
J-1. Sprayer Valve for Dewatering Unit
The team dimensioned this part with Autodesk Inventor software and 3-D printed an Acrylic part
with the department’s ProJet HD3500 plus.
Figure J-1 CAD .idw File of Sprayer Nozzle
XXXIV
J-2. MeOH Column Distributer
The team acquired a condenser that utilized clamp fittings and a packed column that utilized tribolt connections. A team member designed a part that would link the top of the column to the
condenser with a connection for the feed from the catalyst recovery and a tube to distribute the feed to
the middle of the column. The team dimensioned this part with Autodesk Inventor software and 3-D
printed an Acrylic part with the department’s ProJet HD3500 plus.
Figure J-2 MeOH Column Distributer
XXXV
J-3. Bottom Cap for Polishing Column
Figure J-3 FPT fitting for Bottom Cap of the Polishing Column
Figure J-4 MPT Fitting for Bottom Cap of Polishing Column
XXXVI
Appendix K. Schematic Drawings
K-1. Dewatering Schematic
Water
Vapor
Flow to
Fine Filter
2000 W Inline
Heating Element
Ball
Valves
Sprayer
Nozzle
Bulkhead
Fitting
Figure K-1 Schematic of Dewatering System
XXXVII
K-2. MeOH Recovery Schematic
Coolant
Return
Condenser
Coolant In
Vacuum Pump
Feed From Settling Tank
Packed Column
To MeOH Tank
(Raschig Rings)
To Gravity
Column
Reboiler
Thermocouple
2 kW heating element
Figure K-2 MeOH Recovery Schematic
XXXVIII
Drain
K-3. Schematic for Column Train
Biodiesel Product
Stream
Density
Separator
P-5
P-4
Biodiesel
Pump
P-1
Polishing
Column
Biodiesel Product From
Methanol Reboiler
E-6
P-7
P-8
V-1
Glycerol Drain
Valve
Polishing Resin
Amberlite BD10Dry
Biodiesel
Holding Tank
P-6
P-2
E-3 E-2
P-3
E-4
E-1
Figure K-3 Schematic of Column Train to Clean Biodiesel
XXXIX
K-4. Static Inline Mixer Dimensions
Figure K-4 Diagram of Static Mixers Used in Microwave PFR
Screenshot of schematic from http://mixpacstatomix.com/sm-static-mixers-listing.php?series=ME, Team 1 used the elements from Part No. ME 06-24
XL
Appendix L. Calculations
L-1. Dewatering Calculations
Dewatering Calculations
J
Cpoil  1970
kg C
kg
oil  925
3
m
T  80C
Time
Voloil  10gal
Power  2000W
Voloil oil Cpoil T
Power
 45.986min
XLI
L-2. Pressure Drop Across Packed Bed in Polishing Column
Pressure Drop in Resin Bed
Determine the void Volume of the Resin, the void will be different based on the expansion level
of the resin, can expand up to 3x if fully saturated with water.
Material Properties
VolW  20mL
VolR  5mL
3
Void  VolW  VolR  VolT  6.5 10
VolT  18.5mL
1 
av 
Void
VolRW
 0.52
6
 7.895 10
VolRW
VolR
 2.5
L
kg
biodiesel  875
3
m
3
diameterp  0.76 10
3 1
diameterp
Expansion 
VolRW 12.5mL
m
specific surface area of resin particle
(DowChemical)
m
Pressure Drop Calculations
Viscosities of Biodiesel at 40 C
(Brevard BioDiesel)
2
 3 kg
m
kinematic  0.000004
s
dynamic  kinematic
 biodiesel  3.5 10
Assumed Volumetric Flow of Biodiesel
Cross Sectional Area of Column
mL
Volflow  1
s
CrossArea 
Velocity of Biodiesel through Column
v BD 
Volflow
CrossArea
P 
diameterp
2
2
4
3 2
   1.14 10
m
ColL 15in  0.381m
s
Pressure Drop for Laminar Flow
32 dynamic v BD ColL
( 1.5in)
Height of Packed Bed
4m
 8.771 10
m s
Height Equivalent of Biodiesel
P
 64.8
kg
m s
2
g
3
HEqoil 
 7.552 10
biodiesel
XLII
m
L-3. MeOH Recovery Calculations
Heat capacities for FAME and glycerol at 333K (60°C) were used for energy calculations in the
column. These heat capacities were calculated by interpolating from CP values at 300 and 400K (Borghi).
Table L-1 Summary of Properties of Components of PFR Stream
Cp @ 300K Cp @ 400K Estimation of Cp
Molecular
(cal/mol/K) (cal/mol/K) @ 333K (cal/mol/K)
Weight
27.5
34.1
29.678
92.09
84.5
109.9
92.882
270.46
89.8
115.6
98.314
292.46
91.4
118
100.178
294.48
92.7
120.4
101.841
296.5
94.2
122.7
103.605
298.52
Percent
Weight
12.0
6.0
52.0
25.0
5.0
Estimation of Cp
@ 333K (J/g/K)
1.35
1.44
1.41
1.42
1.44
1.45
1.43
Component
Glycerol
Palmitic Acid
Linolenic
Linoleic Acid
Oleic Acid
Stearic Acid
FAME
*The CP for MeOH at 333K was found to be 3.73 J/g/K using UniSim and the heat of vaporization for MeOH 36.2 kJ/mol (1.13 kJ/g).
Multiplying the stoichiometric volumes by the densities from Table 4-1 and performing a material
balance at 100% conversions yields the following liquid product stream for a 1:1 vol. ratio of
MeOH:triglycerides.
Table L-2 Ideal Liquid Reactor Effluent
Value
Flow (mL/s)
Flow (g/s)
MeOH
0.87
0.69
FAME
1.06
0.93
Glycerol
0.078
0.098
The energy balance can now be performed. The heating requirements are to vaporize the MeOH at
50°C and heat to raise the glycerol and FAME temp. from 50°C to 70°C, as the reboiler temperature will
be maintained at 70°C to achieve near 100% MeOH vaporization. The cooling requirement will be to
condense the MeOH at 50°C.
𝑔
𝑘𝐽
𝑄̇𝑐𝑜𝑜𝑙 = 𝑚̇𝑀𝑒𝑂𝐻 ∗ ∆𝐻𝑣𝑎𝑝, 𝑀𝑒𝑂𝐻 = (0.69 ) ∗ (1.13 )
𝑠
𝑔
𝑄̇𝑐𝑜𝑜𝑙 = 0.78 𝑘𝑊
𝑄̇𝐻𝑒𝑎𝑡
𝑄̇𝐻𝑒𝑎𝑡 = 𝑚̇𝑀𝑒𝑂𝐻 ∗ ∆𝐻𝑣𝑎𝑝, 𝑀𝑒𝑂𝐻 + 𝑚̇𝐹𝐴𝑀𝐸 ∗ 𝐶𝑃,𝐹𝐴𝑀𝐸 ∗ ∆𝑇 + 𝑚̇𝐺𝑙𝑦𝑐𝑒𝑟𝑜𝑙 ∗ 𝐶𝑃,𝐺𝑙𝑦𝑐𝑒𝑟𝑜𝑙 ∗ ∆𝑇
𝑔
𝑘𝐽
𝑔
𝐽
𝑔
𝐽
= (0.69 ) ∗ (1.13 ) + [(0.93 ) ∗ (1.43
) + (0.098 ) ∗ (1.35
)] ∗ (70 − 50)°𝐶
𝑠
𝑔
𝑠
𝑔∗𝐾
𝑠
𝑔∗𝐾
𝑄̇𝐻𝑒𝑎𝑡 = 0.81 𝑘𝑊
Due to heat loss, the heating requirement will have to be slightly higher.
XLIII
L-4. PFR Flow Rate Estimate (95% Conversion)
At a 1:1 MeOH:WCO Ratio,
Table L-3 Summary of PFR Stream Flow Rates
B100
B100
mols/hr mols/hr
gal/hr oil
(gal/hr)
mols/hr
Glycerol MeOH
1
12.2
12.2
93.5
0.99
This estimate was arrived via the following calculations:
Reaction Conditions
Conversion  0.95
B100flowVol 1
gal
g/hr CaO
171.1
MeOHtoOil  1
hr
total
L/hr
8.72
total ml/s
2.42
WtFracCatalyst  0.05
Material Properties
WCOdensity  0.915
gm
MeOHdensity  0.791
ml
gm
BiodieselMW  283.52
mol
Glyceroldensity  1.25
MeOHMW  32.04
gm
SoyOildensity  0.915
ml
gm
ml
gm
SoyOilMW  872.33
mol
mol
gm
GlycerolMW  92.09
ml
gm
gm
mol
Flow Rates
B100flowMoles 
WCOdensity
mol
B100flowVol  12.217
BiodieselMW
hr
mol
GlycerolflowMoles  12.217
hr
GlycerolflowMoles  B100flowMoles
GlycerolflowVol  GlycerolflowMoles
GlycerolMW
Glyceroldensity
MeOHflowMoles  B100flowVolMeOHtoOil


MeOHflowVol  MeOHflowMoles 
OilflowVol  B100flowVol
MeOHMW
MeOHdensity
3
4m
 9  10
MeOHdensity
MeOHMW
4
9 10
hr
mol
 93.454
hr
3
3m
3.785m
hr
1000
 3.785 10
3
 m  0.9L
3
 3.785L
gm
CaOflowMass  OilflowVolWtFracCatalyst

 SoyOildensity  173.183
hr
SoyOilflowVol  ( 1  Conversion)  B100flowMoles 
1

SoyOilMW
 3 SoyOildensity
3
4m
 1.941 10
hr
SoyOilflowVol=1.941L/hr
RctrflowVolEst   B100flowVol GlycerolflowVol  MeOHflowVol 


CaOflowMass
3.3
XLIV
gm
ml
 SoyOilflowVol


3
3m
RctrflowVolEst  8.717 10
hr
3
8.717m
=8.72L/hr
1000
 8.717L 8717 ml/3600s=2.42ml/s
L-5. Microwave Power Implications
With most of the microwaves absorbed by the methanol, glycerol, and catalyst
Tin (C)
55 C
0.25" dia, 1 gal/hr
Power into mix (J/s)
@100% cycle
1200
T out
Cp J/mlK
2.12
62 C
Pwr gain,J/s
%cycle
24.47
3.1%
ml/s to 40% cycle
21.00
L-6. PFR Linear Velocity & PFR Volume
velocity (in/s)
vel. (m/s)
Vol.Rate/Dia=
3.012
0.078
300’ of PFR
/ 3.012(in/s)=
19.9 minutes
100’*3.14* (InsideDia./2)2
100’*3.14* (InsideDia+1/8” /2)2
14.25” *
(8”+7/8”) *
16.375”
XLV
Length of PFR=
100 '
Inside Dia.=
Vol. inside PFR=
Vol. of PFR=
0.25 "
0.97 L
2.17 L
=
=
= Vol. of Microwave
33.9
L
L-7. Project Power Requirements & Added Energy Content/Cost
Table L-4 Summary of Power Requirements, Energy Input:Embodied Energy
Device
2000 watt heating coil
2000 watt heating coil
Commercial Microwave
4 X FMI Metering Pumps
Dewatering Pump
Vacuum Pump
CSTR Agitator Pump
FieldPoint Modules
CTB Cooling Unit
LabVIEW Computer +
Monitor
Miscellaneous Components
Totals
Energy to heat oil
(J/galBD100)
Energy to get MeOH to 60C
(J/galBD100)
Energy needed to react oil
(J/galBD100)
Power
(watts)
2000
2000
1800
200
60
528
225
40
1440
Max
Current (A)
16.7
16.7
15
1.64
0.5
4.4
2.5
1.2
12
120 V
(Y/N)
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Current Spike on Start
(A)
NA
NA
Slight
NA
Slight
33
(Possibly high)
NA
Slight
300
2.5
Yes
NA
500
9093
4.2
77.3
Yes
NA
551832
=
153
watts @ 1 gal BD100/hr
234792
=
65
watts @ 1 gal BD100/hr
-841
=
0
watts @ 1 gal BD100/hr
(ΔHr = -16.45kcal/mol=68.83kJ/mol)
B100 (Btu/gal)
B100 (kW-hr/gal)
@ 1 gal/hour (watts)
% Input Energy of
Embodied Energy
@$0.14/kWhr, Electric
Cost($)/Gal
Lower
Heating
Value
119550
35.037
35037
Higher
Heating
Value
127960
37.501
37501
26.6%
24.8%
1.30
XLVI
Appendix M.
M-1.
Pictures of System
Baffles in CSTR
The baffle for the CSTR was constructed of aluminum, highly resistant to biodiesel and WCO. The
dimensions for the baffle design are 10.5” OD, 6.6” ID holding ring, with four 1” X ¼” X 20” baffles
spaced equidistant around the ring. Set screws were used to prohibit rotation or sliding of the baffles in
the slots. Additional set bolts were used to tighten the baffle ring to the glass wall of the tank. Plastic
pads were used as cushions to prevent interaction between the glass and aluminum. Finally, a
tensioning rod was threaded through each of the baffles above the ring to project the bottom of the
baffles to the perimeter of the tank, away from the agitator blades.
Figure M-1 Top View of Baffle Design in CSTR
XLVII
M-2.
MeOH Recovery Unit
Condenser
Hose to Vacuum
Distributer
Packed
Column
MeOH Tank
Reboiler
Figure M-2 MeOH Recovery Unit
XLVIII
M-3.
Density Separator
Biodiesel Outlet
Column Feed
Glycerol Drain
Figure M-3 Density Separation Column
XLIX
M-4.
Polishing Column
Biodiesel Inlet
Approximate Height
of Packed Bed
Biodiesel Outlet
Column Cap
Figure M-4 Empty Resin Column
L
M-5.
Control System
Figure M-5 Overview Of Physical Modules and Connections of Control System
LI
M-6.
Overall System
Figure M-6 Completed Prototype
LII