Malcolm Hegeman Varun Mangla Sheng Zheng...

Transesterification of Soybean Oil

Malcolm Hegeman

Varun Mangla

Sheng Zheng

Brown Industries, INC.

October 1, 2012

Transesterification of Soybean Oil:

Investigation on the operating limits and

reproducibility of transesterification reaction

Malcolm Hegeman, Team Leader

Varun Mangla, Process Engineer

Sheng Zheng, Process Engineer

Brown Industries, INC.

Test Laboratory

Final Report

Monday Section

October 1, 2012

We have neither given nor received

unauthorized help on this report, nor have

we concealed a violation to the honor

code.

________ ________ ________

Malcolm Hegeman Varun Mangla Sheng Zheng

ABSTRACT ..................................................................................................................................... 4

1. OVERVIEW ................................................................................................................................ 5

1.1 Objectives ........................................................................................................................... 5

1.2 Summary of key results ....................................................................................................... 5

2. BACKGROUND ......................................................................................................................... 7

2.1 Industrial Background ......................................................................................................... 7

2.2 Theoretical Background ...................................................................................................... 7

3. MATERIAL AND METHODS ................................................................................................ 10

3.1 Equipment ......................................................................................................................... 10

3.2 Materials ........................................................................................................................... 11

3.3 Experimental Procedure .................................................................................................... 11

4. RESULTS AND ANALYSIS ..................................................................................................... 13

4.1 Operating limits of the transesterification apparatus ......................................................... 13

4.2 Calculation of mass fraction of species in the reactor from GC analysis .......................... 18

4.3 Composition profiles ......................................................................................................... 20

4.4 Reproducibility of the FAMEs conversion profile ............................................................ 21

4.5 Preliminary study on the effect of catalyst on conversion profile ..................................... 24

3. DISCUSSION ............................................................................................................................ 25

3.1 Uncertainties analysis for the mass fraction calculation ................................................... 25

3.2 Experimental techniques ................................................................................................... 27

4. CONCLUSION AND RECOMMENDATION ....................................................................... 28

5. REFERENCE ............................................................................................................................ 30

6. LIST OF APPENDICES ........................................................................................................... 32

4

ABSTRACT

Brown Industries testing team conducted the tranesterification of soybean oil to

produce biodiesel (mainly consists of FAMEs) using the experimental apparatus at the

testing facility. We established the operating limits of the our experimental

apparatus in the following four aspects

∙ Reactor temperature

∙ Catalyst concentration

∙ Agitation speed

∙ Molar ratio of soybean oil to methanol

The operating limits were established based on both experimental and literature

studies.

We defined a set of reference run conditions under which 4 sets of reproducible data

in terms of the conversion rate were obtained. The conversion rate obtained in our

experiments is consistent with the reported conversion rate in literature under

identical operating conditions.

Additionally, we also performed a preliminary study on the effect of catalyst

concentration on the conversion rate. We observed that higher catalyst concentration

results in higher conversion rate.

5

1. OVERVIEW

The board of directors of G.G. Brown Industries has recently decided to extend the

focus of the company to incorporate biodiesel production. The use of biodiesel has the

potential to benefit the economy and environment, both on local and global scales. A

new plant with an annual output of 10 million gallons of first generation biodiesel has

been proposed to be built in Milan, Michigan. G.G. Brown also intends to eventually

branch out to the production of third generation biodiesel, using the microalgae strain

of Chlorella vulgaris as the feedstock. However, prior to the implementation of any

new facilities, we must assess the feasibility of unit operations essential to the process

at the pilot scale.

1.1 Objectives

On September 6, 2012, our team received a memo instructing us to execute a

feasibility study of the transesterification reaction to yield biodiesel using purified

soybean oil and methanol with sodium methoxide as the catalyst. The purpose of our

assessment is to provide information for the next rotation teams to obtain reproducible

data in Design of Experiments (DoE). Our assessment focuses on accomplishing the

following 3 objectives:

∙ Establish the operating limits of the experimental apparatus

∙ Generate reproducible data in terms of the conversion rate under a defined set

of reference run conditions.

∙ If time permits, conduct preliminary study on the effect of operating conditions

on the conversion rate

The purpose of this report is to present the results that our team produced to meet all

of the above objectives.

1.2 Summary of key results

We established the operating limits of our experimental apparatus based on both

experimentation and literature research. We defined a set reference run conditions

which allowed us to generate four sets of reproducible data in terms of the mass

fraction of FAMEs in the reactor as a function of time. We also conducted a

preliminary study on the effect of catalyst concentration on the conversion rate.

6

1.2.1 The operating limits

We propose that the reactor to be operated at a temperature within the range of 30oC ~

60 oC based on the temperature limits on the heating and cooling stream supplies. We

propose the agitation speed to vary within the range of 300 ~ 1000 rpm to achieve

proper turbulent mixing of the reactants without the occurrence of extensive

mechanical vibration and vortex formation. The operating limits on the molar ratio

(soybean oil:methanol) as well as the catalyst concentration are not fixed. However,

based on a screen of the conditions reported in literature, we proposed to operate the

reaction at a molar ratio between 3:1 and 20:1 and at a catalyst concentration between

0.1wt% and 2 wt%.

1.2.2 Reference run conditions and reproducibility of the conversion rate

We conducted four reference runs under the following conditions

Chemicals Amount Mole (mol) Notes

Soybean Oil 266 grams 0.288 Molar ratio 6:1

Methanol 54.4grams 1.734

Sodium Methoxide 0.532 grams 9.86×10-3

0.2wt% based on

the weight of

soybean oil

Operating Conditions Values

Temperature (oC) 50

Agitation Speed (rpm) 600

For each run, we obtained the conversion profile in the reactor as a function of time.

The conversion profiles we obtained are statistically equivalent. In addition, the

conversion profiles we obtained are consistent with the conversion profile reported in

the literature under similar operating conditions.

7

1.2.3 Preliminary investigation on the effect of catalyst concentration on the conversion

rate

We conducted one additional run to investigate the effect of catalyst concentration on

the conversion rate. We discovered that initial conversion rate increases for

approximately 20% when the catalyst concentration is increased from 0.1 wt% to 0.2

wt%. In addition, the conversion achieved after 30 minutes with 0.2 wt% catalyst

concentration is approximated 1.5 times the conversion rate achieved with 0.1 wt%

after the same amount of time.

2. BACKGROUND

We examined both industrial background and theoretical background of our process to

better understand the context of our experiment.

2.1 Industrial Background

In order to develop alternatives to fossil based fuels and establish national energy

independence, renewable fuels have increasingly been receiving attention, specifically

oil producing material such as soybean. The oil derived from these crops can be

converted to a biodiesel product by means of transesterification. Biodiesel is

advantageous over other renewable energy sources, such as wind or solar, because of

its ability to be utilized as a ‘drop in’ fuel, which can be used in internal combustion

diesel engines, but without compromising performance. While biodiesel derived from

terrestrial crops is an attractive solution for producing renewable fuel, there are many

negative externalities that must also be taken into consideration, such as direct and

indirect land use, irrigation water requirements, and using a crop for fuel versus food.

[1]

2.2 Theoretical Background

The overall reaction under consideration is sodium methoxide base-catalyzed

tranesterification of triglyceride (purified soybean oil) with methanol to produce

triglycerol and fatty acid methyl esters (FAMEs). Prior research of this reaction shows

intermediates of diglyceride and monoglyceride, with each reaction being reversible.

The figured displayed below outlines the separate reactions that take place.

8

1

3

6

5

2

42

3 1 3

3 3

3 33

k

k

k

k

k

k

TG CH COOCH

DG CH COOCH

MG CH COOC

OH DG R

OH MG R

OH G HL R

Yielding an overall reaction of:

7

83 33 3

k

kTG CH COOCO HH GL R

Due to the fact that each intermediate reaction and the overall reaction are reversible,

it is important to investigate the effect of operating conditions on the chemical

equilibrium as well as the reaction rates. Reaction under favorable operating

conditions should be able to achieve a maximum extent of reaction at the chemical

equilibrium. In addition, reaction under favorable operating conditions is expected to

occur at a relatively high reaction rate, which allows a higher conversion to be

achieved within limited amount of time.

Critical parameters that affect both the chemical equilibrium and the rate of reaction

include the reaction temperature and the molar ratio of soybean oil to methanol. It is

reported that the transesterification between methanol and triglyceride (the relevant

reactant in soybean oil) is endothermic. [2] Therefore the chemical equilibrium

towards product formation is favored at high temperature. In addition, it is also

reported that the reaction rate constant for transesterification can be described

according to Equation (1) [3]

/n E RTk AT e (1)

According to Equation (1), higher reaction rate constant and consequently higher

reaction rate is achieved at higher temperature. Based on the two reasonings

presented above, it is desired to conduct the tranesterification reaction at a relatively

high temperature.

It is expected that a large molar ratio of methanol to soybean oil drives the reaction

toward product formation. However, a large amount of methanol in the reaction

mixture would also significantly dilute the soybean oil and result in a decrease in the

reaction rate. Therefore, an optimal molar ratio should be determined to achieve

high conversion within relatively short period of time.

9

In contrary to the reactor temperature and the molar ratio, operating conditions

including the catalyst concentration and agitation speed only affect the reaction rate

without shifting the chemical equilibrium.

Due to the fact the tranesterification reaction occurs heterogeneously at the interface

between the two reactive phases, it is expected that high agitation speed will facilitate

the mixing of the two reactive phases and accelerates the reaction.

A high catalyst concentration commonly leads to higher reaction rate. However, in

the case of transesterification catalyzed by sodium methoxide, excess amount of

catatlyst allows the soap forming side reactions. [4] Side reaction will decrease the

purity of the biodiesel product and also cast further challenge in post-processing after

reaction. Therefore, an optimal amount of catalyst also needs to be determined.

10

3. MATERIAL AND METHODS

The following equipment, materials, and experimental procedures were used to

conduct our experiment.

3.1 Equipment

Figure 1 shows a layout of the experimental apparatus [5] for transesterification

reaction and the detailed description of each critical element of the apparatus are

summarized in Table 1.

Figure 1: Layout of the experimental apparatus

Table 1: Description of critial elements in the apparatus

Element Description

(a) A cylindrical jacketed Pyrex glass tank – Chemglass brank model

CG-1931-2 with inside dimensions approximately 97 mm diameter by

320 mm high

(b) A top-entry variable-speed agitator

(c) Thermal couple to measure the jacket temperature

(d) Thermal couple to measure the reactor temperature

(e) Two feed pumps to charge the reactor with methanol and soybean oil

(f),(g) Drain/sampling port to drain the reactor or withdraw sample from the

reactor

(a)

(b)

(f)

(g)

(e)

(d)

11

It should be noted that there is also a manual feed port on the top of the reactor (not

marked in Figure 1) which allows manual injection of catalyst solution into the

reactor.

In addition to the main experimental apparatus, the following equipment is required to

conduct the experimentation with the transerterification apparatus

∙ A rpm gun to measure the agitation speed

∙ Shimadzu GC-2010 Gas chromatography for the analysis of product

composition and monitor the extent of reaction

∙ LabView data acquisition software for reaction temperature monitoring

3.2 Materials

The following materials are required to conduct the experiments.

∙ Soybean oil (Reactant 1), Methanol (Reactant 2)

∙ 5.4 M Sodium methoxide (Catalyst)

∙ Vials and syringes with proper sizes (GC Analysis)

∙ Cooling water supply

∙ Steam supply

3.3 Experimental Procedure

We first performed the start-up procedures according to the SOP for

transesterification reactor [5] in order to provide cooling water and steam supply to

the apparatus.

Before we started to conduct the transesterification reaction, we first washed the

reactor according to the SOP for reactor washing [5] in order to eliminate the potential

remaining catalyst from the previous lab session. This was done by loading 200 mL of

isopropyl alcohol into the reactor, stirring for 30 seconds, and draining. The process

was repeated twice more.

After the reactor was washed, we first charged the reactor with 55.4 grams (mole) of

methanol and 266 grams (mole) of soybean. The molar ratio between the reactants is

methanol: soybean oil = 6:1. After the reactor was charged, we tuned the knob on

the stirred to achieve an agitation rate of 600 rpm. We then set the reactor

12

temperature to 50 oC through the LabView control panel. After the reactor

temperature reached 50 oC and remained at that level, we added 1.9 mL of the 5.4 M

sodium methoxide – methanol mixture (the amount of sodium methoxide in this

solution is equivalent to 0.2 wt% of the amount of soybean oil) to the reaction in order

to start the reaction. We sampled the reaction mixture after 0 minute, 1minute, 2

minutes, 4 minutes, 7 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes and

30 minutes for composition analysis by GC. The GC samples were prepared from

the reaction mixture samples according to the SOP for GC analysis. [6] The

composition analysis of the reaction mixture at different times provided us with data

to investigate the rate of the transesterification reaction and consequently generate a

conversion profile with respect to time. Table 2 summarizes the feed and operating

conditions we tested.

Table 2: Proposed operating conditions for the reference run





0.2wt% based on

the weight of

soybean oil


Temperature (oC) 50


The conditions summarized in Table 2 are defined as the reference run conditions.

We repeated the experiments with the reference run conditions three more times.

In addition to the previous set of conditions as summarized in Table 2, we also

performed one experiment with 0.1 wt% of catalyst based on the weight of soybean

oil while keeping other conditions unchanged in order to qualitatively study the effect

of catalyst amount on the conversion profile. The second set of operating conditions

that we tested is summarized in Table 3.

13

Table 3: Operating conditoins to study the effect of catalyst concentration on the reaction





0.1wt% based on

the weight of

soybean oil


Temperature (oC) 50


4. RESULTS AND ANALYSIS

In this section, we will first present the analysis on operating limits based on both

experimentation and literature studies.

The critical indicator of the reaction rate is the mass fraction of FAMEs in the

reaction mixture at different times. In this section, we will present a comprehensive

data analysis procedure to obtain the mass fraction of FAMEs in the reaction mixture

from GC analysis. Secondly, we will analyze the reproducibility of the conversion

profile. Additionally, we will also present a preliminary study on the effect of

catalyst amount on the conversion profile.

4.1 Operating limits of the transesterification apparatus

According to the SOP for transesterification reaction [5], the reactor temperature

could not exceed 60oC. Therefore, 60

oC is defined as the upper operating limit for

temperature. In addition, the lowest temperature that the reactor can achieve is

governed by the temperature of the cooling water (~30 oC). Consequently, the

reactor temperature could be varied from 30 oC to 60

oC in the DoE studies. In

addition, as is stated in Section 2.2 that transesterification reaction is a reversible

endothermic reaction, therefore, high reaction temperature favors the chemical

equilibrium towards and product formation as well as a high reaction rate.

Since transesterification reaction occurs at the interface between the methanol phase

and the soybean oil phase, intensive mixing by the impeller is critical to facilitate the

reaction. The extent of turbulent mixing by the impeller can be characterized by the

Reynolds number as defined in Equation (2).

14

Re

nDaN

(2)

is the Reynolds number

is the rotation speed of the impeller

is the diame

is the density of the fluid

is

ter o

the viscosity of the

f the impel

flui

ler

d

ReN

n

Da

Assuming mass-averaged density and mass-averaged viscosity calculated from the

density and viscosity of methanol and soybean oil, we calculated the Re number for

the fluid mixing at different agitation speed. Table 4 shows Re for agitation speed

varying from 150 to 1200.

Table 4: Calculated mixing intensity, NRe for different agitation speed

The calculated Re for our system is comparable to the Re calculated and reported by

Noureddini and Zhu. [3] The Re number in Noureddini and Zhu’s study is

NRe(150 rpm) = 3100

NRe(300 rpm) = 6200

NRe(600 rpm) = 12400

Figure 2 shows the effect of mixing on the conversion of FAMEs according to

Noureddini and Zhu’s study.

n (/s) Da (m) ρ AV (kg/m3) μ AV(Pa s) N Re

300 0.05 892.79 0.07 5105.85

600 0.05 892.79 0.07 10211.71

900 0.05 892.79 0.07 15317.56

1200 0.05 892.79 0.07 20423.41

15

Figure 2: The effect of mixing on the conversion rate, reproduced from [3]

It is seen from Figure 2 that the conversion rate at NRe (150 rpm) = 3100 is

significantly lower than the conversion rate at NRe (300 rpm) = 6200 and NRe (600

rpm) =12400, indicating inadequate mixing at NRe = 3100. Consequently we

recommend operating the reactor at an agitation rate of at least 300 rpm.

The mechanic stirrer can provide a maximum agitation speed exceeding 1000 rpm.

However, the transesterification apparatus vibrates intensively at agitation speed

higher than 1000 rpm. The mechanical vibration might leads to uncontrollable

uncertainties in the experiments. Therefore, we don’t recommend operating the

reaction at agitation speed higher than 1000 rpm.

The experimental apparatus does not cast any operating limits upon the molar ratio

and catalyst concentration. Reaction with different molar ratios can be achieved by

charging the reactor with different amount of soybean oil and methanol. It is

expected that a high molar ratio of methanol to soybean oil would favor the chemical

equilibrium towards product formation. We conducted the following analysis to

quantitatively investigate the effect of molar ratio on the chemical equilibrium. In

order to quantitatively characterize the position of the chemical equilibrium, we

choose the conversion of the reactive species in soybean oil, namely the conversion of

triglyceride (XTG) as an indicator of the position of the chemical equilibrium. A

desired chemical equilibrium features a XTG value close to 1, indicating approximately

complete conversion of triglyceride to FAMEs. For a reaction with a molar ratio of x

moles of methanol to 1 mole of triglyceride, the following stoichiometric table can be

constructed.

NRe=3100NRe=6200

NRe=12400

16

Table 5: Stoichiometric table for the reaction with various molar ratio

According to Table 5, the equilibrium constant of the reaction can be expressed as

Equation (3).

33

3 3

[ ] [ ]

[ ] [ ] (1 )(

(3 )

3 )

TG TG

TG TG

XFAMEs GLK

MeOH TG X x

X

X (3)

It is reported that at 60oC, the equilibrium constant K = 0.220. [2] Therefore, for the

reaction with different molar ratios at 60oC, XTG can be expressed as a function of x

by plugging K = 0.220. Figure 1 shows XTG as a function of x

Figure 3: Effect of molar ratio on the conversion rate

It is seen that the conversion of triglyceride increases with increasing molar ratio.

The effect of molar ratio on the conversion is most significant in the region of 3<x<10.

The effect of molar ratio on the conversion is relatively minimal when the molar ratio

is above 15:1. In the meanwhile, excessive amount of methanol significantly dilutes

the triglyceride and thus reduces the reaction rate. Consequently we recommend

operating the reaction at the molar ratio between 3:1 and 15:1.

In order to obtain reproducible data, the impeller, the temperature sensor and also the

sampling tube should be completely submerged in the reaction mixture. Figure 4

shows two scenario with adequate and inadequate amount of reaction mixture.

33T FAG M ME GLeOH s

Start 1 x 0 0

Converted -X TG -3X TG 3X TG X TG

Final 1-X TG -3X TG 3X TG X TG

33T FAG M ME GLeOH s

0.2

0.4

0.6

0.8

1

0 5 10 15 20 25

Co

nve

rsio

n o

f s

oyb

ea

n o

il

Molar ratio of methanol to soybean oil

17

Figure 4: (a) adequate amount of reaction mixture (b) inadequate amount of reaction mixture

because the thermal couple is not submerged in the reaction liquid

Therefore, in addition to the molar ratio, we recommend operating the reaction with a

reaction mixture with total volume greater than 360 mL.

The catalyst concentration can adjusted by changing the volume of the sodium

methoxide solution that is used. It is expected that a higher catalyst concentration

results in a higher reaction rate. However, in the case of transesterification, excess

amount of catalyst allows soap forming side reactions. [4] The side reaction is

undesired because it reduces the purity of the biodiesel and cast further challenge in

separation and purification after reaction. In most previous researches, the catalyst

concentration was varied from 0.1 wt% to 2.0 wt%. Therefore, we recommend

operating the reaction catalyst concentration from 0.1 wt% to 2.0 wt% in the DoE

studies. The proposed range for operating conditions is summarized in Table 6.

Table 6: Proposed operating limits based on experimentation and literature studies

(a) (b)

molar ratio (MeOH:soybean oil) 3:1~15:1

agitation speed (rpm) 300~1000

reaction temperature (oC) 30~60

catalyst concentration (wt%) 0.1~2.0

18

4.2 Calculation of mass fraction of species in the reactor from GC analysis

It should be clarified that GC analysis provides the weight percentage of relevant

chemical species including FAMEs, mono-, di-, tri-glyceride, and glycerol in the GC

sample. However, the weight percentage of FAMEs in the GC sample does not

equal the weight percentage of FAMEs in the reaction mixture because reaction

mixture is diluted by pyridine, MSTFA and heptanes during the GC sample

preparation. The procedures for GC sample preparation together with important

mass measurements are shown in Figure 5.

Figure 5: The procedure for GC sample preparation with key measurements

It should be noted that only a portion of the reaction mixture – pyridine solution was

transferred into the MSTFA solution for further sample preparation. Therefore, the

mass of the GC sample accounts for the mass of MSTFA in the GC vial and a portion

of the mass of the reaction mixture – pyridine solution, namely p(mr+mp), where p is a

portion factor between 0 and 1.

For a particular species i in the reaction mixture with mass fraction xi, the mass of

species i in the reaction mixture and also in the reaction mixture-pyridine solution is

mrxi. Consequently, the mass of species i that is transported into the GC vial equals

pmrxi. Therefore, the mass fraction of species i in the GC sample, namely x’i can be

expressed according to Equation (4)

Reaction mixture,

xFAMEs, mr

Reaction mixture in

pyridine, mr+mp

Pyridine, mp

MSTFA, mm

A portion of Reaction mixture in pyridine

mixed with MSTFA, p(mr+mp)+mm

measured

Composition Analysis by GC, x’FAMEs

GC sample, p(mr+mp)+mm+mh

heptane, mh

19

'( )

r ii

r p m h

xp m m

pm x

m m

(4)

is the mass of reaction mixture withdrawn from the reactor

is the mass of the pyridine solution

is the mass of MSTFA

is the mass of heptane

is the mass fraction of species i in the reactor

r

p

m

h

i

m

m

m

m

x

' is the mass fracton of species i in the GC sample

is the portion factor that accounts for the partial transfer

ix

p

It should be noted that x’i is directly measured by GC analysis.

If we define

1

2

3

4

5

The 1st mass measurement

The 2nd mass measurement

The 3rd mass measurement

( ) The 4th mass measurement

( ) The 5th mass measurement

p

p r

m

p r m

p r m h

m m

m

m m

m p m m m

m p m m m m

m m

The mass fraction of species i in the reaction mixture, xi can be expressed as shown in

Equation (5)

5

2 1

'[ ( ) ] '/ ( )

( )

ii r p m h i r

m xp m m m m x pm

mx

p m

(5)

Furthermore, the portion factor p can be expressed as

4 3

2

m

mp

m (6)

Plugging Equation (6) into Equation (7) gives

2 5

4 3 2 1

'

( )( )

iix

m

m m x

m m m

(7)

20

Equation (7) allows us to calculate the mass fraction of species i in the reaction

mixture from directly measured mass (m1~4) or mass fraction (x’i). Table 7 shows a

sample data set of mass/mass fraction measurements with respect to FAMEs.

Table 7: A representative set of collected data for the calculation of mass fraction of FAMEs in

the reactor

Equation (8) shows a sample calculation for the mass fraction of FAMEs in the

reaction mixture

6100.105

0.256 0.165

3.135 1.061 549.57

( )(3.135 2.945)ix

(8)

We applied this approach to calculate the mass fraction of each species in the reaction

mixture based on the composition of species in the GC samples. The resulting data

of all 4 runs are attached in Appendix A.

4.3 Composition profiles

We plotted the mass fraction of all relevant chemical species as a function of time to

generate the composition profile within the reactor as a function of time. Figure 6

shows a representative composition profile we obtained from the reference run

conditions.

Definition Value

m 1(g) mass of pyridine 2.945

m 2(g) mass of the reaction mixture - pyridine solution 3.135

m 3(g) mass of MSTFA 0.165

m 4(g) mass of the reaction mixture - pyridine - MSTFA solution 0.256

m 5(g) mass of the GC sample 1.061

x 'FAMEs(ppm) mass fraction of FAMEs in the GC sample 549.57

21

Figure 6: Mass fraction profiles for relevant reacting species in the reactor

The composition profiles for other 3 runs are attached in Appendix B.

It is seen from Figure 6 that the mass fraction of FAMEs and glycerol constantly

increase over time, indicating the formation of the product. In the meanwhile, the

mass fraction of Mono-, Di-, and Tri-glyceride first increase and then decrease,

because these three species are the intermediate products which are first formed and

then consumed.

4.4 Reproducibility of the FAMEs conversion profile

A critical parameter that quantifies the extent of reaction is the conversion of the

reaction. One critical task that was assigned to our team is to generate the

conversion as a function time for the reaction under a defined reference condition.

However, the conversion of the reaction is not directly measured. Instead, the mass

fraction of FAMEs in the reactor is measured by GC and the conversion could be

calculated according to the mass fraction of FAMEs in the reactor. In order to

calculate the conversion from the measured mass fraction, we performed the

following analysis.

According to the reaction equation

33 3OH FAMEs GlycerolTriGlyceride CH

We choose 1 mole of Tri-glyceride as a basis. Under this basis, the number of moles

for methanol is 6 moles because the molar ratio of methanol to soybean oil is 6:1.

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

0 500 1000 1500 2000

Ma

ss F

ractio

n

Time (s)

MonoGlyceride

DiGlyceride

TriGlyceride

Glycerol

FAMEs

22

Suppose the conversion is X, the number of moles of each species can be calculated

according to Equation (9) to Equation (10).

1Triglyceride Xn (9)

6 3MeOHn X (10)

3FAMEs Xn (11)

Glyceroln X (12)

Consequently, the mass fraction of FAMEs in the reaction mixture can be expressed

as shown in Equation (11).

3093

3 309 924(1 ) 32(6 3 ) 92.1

FAMEsFAMEs

Total

m Xx

m X X X X

(11)

Therefore, the conversion X, can be expressed in terms of the mass fraction of FAMEs,

xFAMEs, according to Equation (12).

92

1116

0.97

FAMEs

FAMEs

Xx

x

(12)

Table 8 shows the calculated conversion at different times according to the measured

mass fraction of FAMEs in reactor.

Table 8: Calculation of conversion from the mass fraction of FAMEs

Time(s) x FAMEs X

52 0.10573 0.12727

118 0.18704 0.22514

173 0.28311 0.34074

250 0.35654 0.42908

461 0.45802 0.55115

635 0.49783 0.59904

900 0.56388 0.67848

1184 0.61807 0.74364

1522 0.59593 0.71702

23

The same calculation of conversion from measured mass fraction was also performed

for the other 3 runs under the reference condition. The resulting data is attached in

Appendix C.

Figure 7 shows the conversion profile of FAMEs obtained from four trials under the

reference conditions.

Figure 7: Conversion profile obtained from 4 trials under reference run conditions

It is seen that the conversion profiles obtained from the three trials are statistically

equivalent. Therefore, it is verified that the conversion profile for FAMEs can be

reproduced under the reference conditions.

We also compared the measured conversion profile of FAMEs with the conversion

profile obtained by Noureddini and Zhu[3] under identical operating conditions.

Figure 8 shows the comparison between the conversion profiles we obtained with the

published conversion profile.

-0.4

-0.1

0.2

0.5

0.8

1.1

1.4

0 500 1000 1500 2000

Co

nve

rsio

n

Time (s)

Trial 1

Trial 2

Trial 3

Trial 4

24

Figure 8: Comparison between the measured conversion profile with the reported conversion

profile

It is seen from Figure 8 that the conversion profile we obtained is consistent with the

conversion profile of the first 30 minutes obtained in the literature, which further

verifies the reproducibility of FAMEs conversion profile under the reference

conditions.

4.5 Preliminary study on the effect of catalyst on conversion profile

In order to provide insight for the effect of catalyst concentration on the conversion

profile, we conducted one experiment with half of the catalyst concentration, namely

0.1 wt%, as we used for the reference runs. We repeated the analysis to obtain the

mass fraction of each species as a function of time and also the conversion profile.

The relevant data is attached in Appendix D. Figure 9 shows the comparison of the

conversion profile of FAMEs between this run with 0.1wt% catalyst and the reference

run with 0.2 wt% catalyst.

LiteratureThis work

25

Figure 9: The effect of catalyst concentration on the conversion

It is seen that the initial conversion rate is higher for the run with 0.2 wt% catalyst,

which is consistent with the expectation that higher catalyst concentration increases

the reaction rate more significantly than lower catalyst concentration. In addition,

the final conversion achieved with 0.2 wt% catalyst concentration after 30 minutes is

approximately 1.5 times higher than the conversion achieved with 0.1 wt% catalyst

after the same amount of time.

3. DISCUSSION

3.1 Uncertainties analysis for the mass fraction calculation

According to Equation (7), the mass fraction of each chemical species is calculated

based on 5 weight measurements and the GC measurements. Therefore, the

uncertainties in the 6 measured variables will propagate into the uncertainty in the

calculated mass fraction. The uncertainty in the calculated mass fraction can be

calculated according to Equation (13).

2 2 2

~ '

2

1 5 ( ) ( )'i j i

i ix j m x

j i

x x

m x

(13)

By plugging in the expression for xi, we obtained the following equations

2 22 5

4 3 2

2

1 1

[ ]( )( )

( )i m

m

x m

m m mm

(14)

-0.6

-0.3

0

0.3

0.6

0.9

1.2

1.5

0 500 1000 1500 2000

Co

nvers

ion

Time (s)

0.2 wt%

0.1 wt%

26

2 25 4 3 2 1 2 5 4 3

2 2

2 4 3 2 1

( )[

(]

( ) ( )

) ( )( )ix m m m m mm

m m

m m m

m m m

(15)

2 22 5

4 3 2 1

2

3

[ ]( ) ( )

( )i m

m

m

m mm

x

m

(16)

2 22 5

4 3 2 1

2

4

[ ]( ) ( )

( )i m

m

m

m mm

x

m

(17)

2 22

4 3 25 1

[ ]( )( )

( )i m

m

x

m m mm

(18)

2 22 5

4 3 2 1

2 '[ ]

' ( )()

)( i i

i

m m x

x m m

x

m m

(19)

The uncertainty in the weight measurements is governed by the accuracy of the scale,

which is 0.0001g ( ( 1~ 5) 0.001jx j ). The uncertainty of the GC analysis is

within 10 ppm. According to Equation (14) to (19) and the uncertainties in each

measured variable, we performed the uncertainty analysis to determine the propagated

uncertainty in xFAMEs. We present a sample uncertainty analysis for the data set shown

in Table 9.

Table 9: A representative data set used for uncertainty calculation

The calculated uncertainty contribution from each measurement together with the

total uncertainty in the mass fraction of FAMEs is shown in Table 10.

m 1(g) 2.945

m 2(g) 3.135

m 3(g) 0.165

m 4(g) 0.256

m 5(g) 1.061

x 'FAMEs(ppm) 152.970

27

Table 10: Distribution of uncertainty by error propagation analysis

It is seen from Table 10 that the uncertainty contributed by m3 and m4 measurements

account for 90% of the uncertainty in xFAMEs. m3 and m4 measurements introduce

significant uncertainties into xFAMEs because the quantity “m4-m3” is a small number in

the denominator in Equation (16) and (17). The quantity m4-m3 represents the mass

for reaction mixture – pyridine solution transferred into the MSTFA-containing vial.

Therefore, introduce a larger amount of reaction mixture-pyridine solution in the

MSTFA-containing vial will reduce the propagated uncertainty in xFAMEs.

3.2 Experimental techniques

We provide the following tips on experimental techniques in order to help the team

engineers to obtain reproducible data in the following DoE studies.

3.2.1 Timing the reaction

It should be noted that the transesterification reaction continues to occur in the

sampling syringe and also in the pyridine-containing vial after the sample is

withdrawn from the reactor. Therefore, it is incorrect to record the reaction time

immediately after sampling from the reactor. The reaction is stopped once the

sample is mixed with MSTFA because the active hydroxyl groups in the reacting

species are substituted with trimethylsilyl groups from MSTFA. Consequently, the

reaction time for each data point should be recorded immediately after the reaction

mixture sample is injected to MSTFA.

3.2.2 Rinsing the syringe for sampling

It is stated in the SOP that the sampling syringe should be rinsed by the reaction

mixture circulating in the sampling/draining loop before sampling. The purpose of

rinsing the syringe is to remove the remaining fluid in the syringe from the previous

sampling. Because each sampling requires withdrawing 0.2 mL of the reaction

Absolute Relative

m 1 contribution 3.35E-05 0.0%

m 2 contribution 0.01 9.2%




x 'FAMEs contribution 3.46E-13 0.0%

σ x FAMEs2

0.10 100.0%

σ x FAMEs 0.31

28

mixture from the reactor, it is likely that trace amount of the previous sample adheres

to the inner wall of the sampling syringe from 0 mL to 0.2 mL. Consequently, we

recommend rinsing the syringe with at least 0.4 mL of the reaction mixture in the

sampling/draining loop before sampling to assure that the region contaminated with

the previous sample is sufficiently rinsed.

3.2.3 Rinsing the syringe for catalyst inject

We also recommend rinsing the syringe for catalyst injection with the provided 5.4 M

sodium methoxide – methanol solution 3 times before catalyst injection. It is likely

that a fluid film remains in the syringe and also the needle after each catalyst injection.

As methanol evaporates, the sodium methoxide dissolved in the fluid film will

precipitate and remain in the syringe and needle. The remaining sodium methoxide

solids will contaminate the fresh catalyst solution by changing the concentration of

the catalyst solution. Therefore we recommend rinsing the syringe and needle with

the sodium methoxide – methanol solution before each catalyst injection.

4. CONCLUSION AND RECOMMENDATION

During our rotation, we tested the transesterification apparatus with a defined

reference condition. Based on the measured mass fraction of FAMEs in the GC

sample, we calculated the mass fraction of FAMEs in the reactor and consequently the

conversion of the reaction at different times. We plotted the conversion of the

reaction as a function time and compared it with the predicted conversion profile by

previous research. The measured conversion profile is consistent with the predicted

profile. We also compared the conversion profile obtained from different trials with

identical operating conditions to investigate the reproducibility of the conversion

profile. It is found that the conversion profiles from different trials are statistically

equivalent, indicating satisfactory reproducibility. In addition, we carried out a

preliminary study on the effect of catalyst concentration on the conversion rate. It is

found that the conversion rate is higher for the trial run with higher catalyst

concentration.

We also provided several pieces of advice regarding the experimental techniques in

order to help the next team to achieve satisfactory reproducibility in experimentation.

In addition to the advices on experimental techniques, we further recommend to

include the following two trouble-shooting techniques in the SOP.

29

∙ The main gas flow valve is usually at “OPEN” position (in parallel with the

pipeline). If the main gas flow valve is at “CLOSED” position as indicated in

Figure 10, a low flow alarm will appear on the main control panel.

Figure 10: The status of the main gas flow valve

Therefore, we recommend checking the status of the main gas flow valve at the

beginning of each lab section.

∙ The cavities in the piping system might prevent the cooling water from flowing

through the reactor jacket. If no cooling water flows through the reactor jacket

even the cooling water control is set at “OPEN” position, cavities might exist in

the piping. The cavity can be eliminated by directing the cooling water

through the PFR reactor first. The cooling water can be re-directed back to the

STR reactor after the cavities are eliminate

30

5. REFERENCE

[1] Hass, M. J.; McAloon, A. J. l.; Yee, W. C.; Foglia, T. A. Bioresource Technology,

97(2006), 671-678

[2] Xiao, Y.; Gao, L.; Xiao, G.; Lv, J., Energy and Fuels, 2010, 24(11), 5829-5833

[3] Noureddini, H.; Zhu, D., Journal of the American Oil Chemists’ Society,

11(1997), 1457-1463

[4] Vicente, G.; Martinez, A. C.; Aracil, J.; Industrial Crops and Products, 8(1998),

29-35

[5] LaValle Pablo, Transesterification of Soybean Oil for Producing Biodiesel Fuels,

Laboratory Standard Operating Procedure, March 9, 2012, ChE 460 Course

Package

[6] LaValle Pablo, Transesterification Products Analysis Using the Shimadzu

GC-2010 Gas Chromatograph, , Laboratory Standard Operating Procedure,

March 9, 2012, ChE 460 Course Package

[7] The average molecular weight of the soybean oil is 920 g/mol, Patzek, T. W.; “A

First Law Thermodynamic Analysis of Biodiesel Production From Soybean”,

April 13, 2009

31

6. NOMENCLATURE TABLE

Term Definition Units

n Number of moles Mol

A Frequency factor L/(mol*s)

E Activation energy J/mol

R Gas constant J/(mol*K)

T Temperature °C

k Reaction rate constant

n Rotation speed of the impeller s-1

Da Diameter of the impeller M

ρ Density of the fluid kg/m3

µ Viscosity of the fluid Pa*s

NRe Reynolds numbers

K Equilibrium constant

XTG Conversion of triglyceride

mr Mass of reaction solution drawn from reactor g

mp Mass of pyridine g

mm Mass of MSTFA g

mh Mass of heptane g

m1 Mass of pyridine g

m2 Mass of the reaction mixture- pyridine solution g

m3 Mass of MSTFA g

m4 Mass of the reaction mixture- pyridine- MSTFA solution g

m5 Mass of the GC sample g

x'FAMEs Mass fraction of FAMEs in the GC sample ppm

32

7. LIST OF APPENDICES

Appendix A Calculation of Mass fraction of reacting species in the reactor

Appendix B Composition profiles for reacting species in reactor

Appendix C Conversion from xFAMEs to X

Appendix D Supplementary data for the run with 0.1wt% catalyst

concentration

A-1

APPENDIX A CALCULATION OF MASS FRACTION OF REACTING SPECIES IN THE REACTOR

Table A-11: Mass fraction calculation for the reaction species – reference run trial -1

Time to stop reaction (s) 52.00 118.00 173.00 250.00 461.00 635.00 900.00 1184.00 1522.00 1800.00

m 1(g) 2.95 2.94 2.95 2.95 2.94 2.94 2.94 2.95 2.94 2.94

m 2(g) 3.14 3.14 3.13 3.14 3.14 3.13 3.13 3.13 3.12 4.13

m 3(g) 0.17 0.17 0.17 0.17 0.17 0.16 0.17 0.17 0.17 0.22

m 4(g) 0.26 0.26 0.26 0.26 0.26 0.26 0.26 0.26 0.26 0.32

m 5(g) 1.06 1.00 1.02 1.02 1.00 1.03 1.06 1.04 1.05 1.04

x' MonoG(ppm) 152.97 229.69 249.56 273.21 293.35 241.48 207.23 198.61 157.48 149.56

x' DiG(ppm) 347.04 848.37 672.26 617.40 539.52 456.55 402.69 397.72 334.63 320.37

x' TriG(ppm) 335.23 1641.41 1233.39 1188.00 848.19 693.93 586.77 563.65 450.09 514.17

x' Glycerol(ppm) 15.29 39.84 80.89 122.23 194.06 209.26 217.01 240.37 226.83 231.34

x' FAMEs(ppm) 549.57 1061.10 1508.20 1983.66 2683.09 2711.28 2798.57 3116.32 2910.66 2951.60

x MonoG 0.03 0.04 0.05 0.05 0.05 0.04 0.04 0.04 0.03 0.01

x DiG 0.07 0.15 0.13 0.11 0.09 0.08 0.08 0.08 0.07 0.01

x TriG 0.06 0.29 0.23 0.21 0.14 0.13 0.12 0.11 0.09 0.02

x Glycerol 0.00 0.01 0.02 0.02 0.03 0.04 0.04 0.05 0.05 0.01

x FAMEs 0.11 0.19 0.28 0.36 0.46 0.50 0.56 0.62 0.60 0.11

A-2

Table 12: Mass fraction calculation for the reaction species – reference run trial -2


m 1(g) 2.95 2.95 2.95 2.94 2.94 2.94 2.95 2.94 2.94 2.94

m 2(g) 3.13 3.12 3.13 3.13 3.12 3.12 3.12 3.13 3.13 3.12

m 3(g) 0.16 0.16 0.17 0.18 0.17 0.17 0.17 0.17 0.17 0.17

m 4(g) 0.25 0.25 0.26 0.27 0.26 0.26 0.26 0.26 0.26 0.26

m 5(g) 1.06 1.06 1.06 1.07 1.06 1.05 1.06 1.07 1.03 1.06

x' MonoG(ppm) 188.63 184.89 258.81 275.60 272.57 241.36 213.09 214.44 143.18 149.56

x' DiG(ppm) 810.65 634.84 595.40 564.90 496.65 438.70 406.36 395.08 322.07 320.37

x' TriG(ppm) 1741.45 1602.29 1174.91 1055.53 792.07 648.57 585.97 525.97 427.66 514.17

x' Glycerol(ppm) 15.78 47.45 92.05 134.55 182.13 212.43 233.95 266.48 264.68 231.34

x' FAMEs(ppm) 829.24 1061.84 1607.26 2011.69 2486.27 2598.65 2841.07 3055.36 2960.52 2951.60

x MonoG 0.03 0.04 0.05 0.05 0.05 0.04 0.04 0.04 0.03 0.01

x DiG 0.07 0.15 0.13 0.11 0.09 0.08 0.08 0.08 0.07 0.01

x TriG 0.06 0.29 0.23 0.21 0.14 0.13 0.12 0.11 0.09 0.02

x Glycerol 0.00 0.01 0.02 0.02 0.03 0.04 0.04 0.05 0.05 0.01

x FAMEs 0.11 0.19 0.28 0.36 0.46 0.50 0.56 0.62 0.60 0.11

A-3



m 1(g) 2.49 2.94 2.97 2.95 2.95 2.95 2.95 2.95 2.95 2.95

m 2(g) 2.66 3.13 3.13 3.13 3.12 3.12 3.13 3.14 3.13 3.13

m 3(g) 0.19 0.17 0.16 0.16 0.16 0.17 0.16 0.16 0.16 0.16

m 4(g) 0.28 0.26 0.25 0.26 0.26 0.26 0.26 0.26 0.26 0.26

m 5(g) 1.08 1.07 1.06 1.06 1.06 1.06 1.05 1.07 1.04 1.07

x' MonoG(ppm) 330.73 199.22 263.83 275.77 242.17 218.29 185.48 169.20 147.39 138.54

x' DiG(ppm) 1064.30 742.27 658.54 600.22 503.22 462.53 79.84 366.41 324.58 315.76

x' TriG(ppm) 1793.08 2116.30 1353.77 1067.20 837.70 760.91 630.23 587.69 503.00 484.33

x' Glycerol(ppm) 18.79 58.17 118.00 152.99 200.58 247.21 267.70 309.66 312.92 327.62

x' FAMEs(ppm) 1258.36 1268.25 1920.92 2252.87 2621.05 3012.74 3114.00 3461.00 3402.00 3558.00

x MonoG 0.03 0.04 0.05 0.05 0.05 0.04 0.04 0.04 0.03 0.01

x DiG 0.07 0.15 0.13 0.11 0.09 0.08 0.08 0.08 0.07 0.01

x TriG 0.06 0.29 0.23 0.21 0.14 0.13 0.12 0.11 0.09 0.02

x Glycerol 0.00 0.01 0.02 0.02 0.03 0.04 0.04 0.05 0.05 0.01

x FAMEs 0.11 0.19 0.28 0.36 0.46 0.50 0.56 0.62 0.60 0.11

A-4



m 1(g) 2.94 2.95 2.96 2.95 2.96 2.96 2.95 2.95 2.95 2.95

m 2(g) 3.12 3.13 3.14 3.13 3.14 3.13 3.13 3.14 3.13 3.13

m 3(g) 0.15 0.16 0.16 0.17 0.16 0.17 0.16 0.16 0.16 0.17

m 4(g) 0.25 0.26 0.26 0.27 0.27 0.27 0.26 0.26 0.28 0.27

m 5(g) 1.05 1.07 1.07 1.07 1.06 1.07 1.06 1.04 1.09 1.07

x' MonoG(ppm) 307.02 258.24 319.24 289.20 265.13 236.13 194.82 160.35 183.13 142.14

x' DiG(ppm) 933.49 872.25 858.48 745.06 571.98 504.74 416.51 377.53 447.25 352.22

x' TriG(ppm) 1447.47 1817.53 1656.12 1592.99 1059.74 882.52 752.03 690.98 821.25 618.52

x' Glycerol(ppm) 18.81 34.09 68.24 132.34 203.62 236.09 265.58 289.77 374.02 330.13

x' FAMEs(ppm) 1172.14 1164.05 1614.49 2123.68 2750.04 2942.86 3128.17 3275.35 4197.17 3614.22

x MonoG 0.03 0.04 0.05 0.05 0.05 0.04 0.04 0.04 0.03 0.01

x DiG 0.07 0.15 0.13 0.11 0.09 0.08 0.08 0.08 0.07 0.01

x TriG 0.06 0.29 0.23 0.21 0.14 0.13 0.12 0.11 0.09 0.02

x Glycerol 0.00 0.01 0.02 0.02 0.03 0.04 0.04 0.05 0.05 0.01

x FAMEs 0.11 0.19 0.28 0.36 0.46 0.50 0.56 0.62 0.60 0.11

B-1

APPENDIX B COMPOSITION PROFILES FOR REACTING SPECIES IN

REACTOR

Figure 11: Mass fraction profile of reacting species in the reactor – reference run trial 2


-0.5

0

0.5

1

1.5

0 500 1000 1500 2000

Ma

ss F

ractio

n

Time (s)

MonoGlyceride

Di-Glyceride

Tri-Glyceride

Glycerol

FAMEs

-0.5

0

0.5

1

1.5

0 500 1000 1500 2000

Ma

ss F

ractio

n

Time (s)

Mono-Glyceride

Di-Glyceride

Tri-Glyceride

Glycerol

FAMEs

B-2


-0.5

0

0.5

1

1.5

0 500 1000 1500 2000

Ma

ss F

ractio

n

Time (s)

Mono-Glyceride

Di-Glyceride

Tri-Glyceride

Glycerol

FAMEs

C-1

APPENDIX C CONVERSION FROM XFAMES TO X

Table 151: Conversion from xFAMEs to X – reference run trial 2



Time (s) x FAMEs X

62.00 0.04 0.20

115.00 0.04 0.28

181.00 0.06 0.42

238.00 0.06 0.50

424.00 0.06 0.62

604.00 0.05 0.66

898.00 0.04 0.71

1211.00 0.04 0.72

1484.00 0.03 0.68

1790.00 0.03 0.77

Time (s) x FAMEs X

60.00 0.24 0.29

123.00 0.24 0.29

200.00 0.43 0.52

268.00 0.46 0.55

418.00 0.51 0.62

619.00 0.57 0.69

880.00 0.58 0.70

1185.00 0.64 0.77

1500.00 0.65 0.78

1758.00 0.66 0.79

Time (s) x FAMEs X

51.00 0.23 0.28

110.00 0.23 0.27

170.00 0.30 0.36

225.00 0.38 0.46

437.00 0.47 0.57

613.00 0.55 0.66

901.00 0.57 0.68

1200.00 0.61 0.73

1477.00 0.68 0.82

1784.00 0.64 0.77

D-1

APPENDIX D SUPPLEMENTARY DATA FOR THE RUN WITH 0.1WT% CATALYST CONCENTRATION

Table 18: Mass fraction calculation for the reaction species


m 1(g) 2.95 2.95 2.95 2.95 2.95 2.95 2.95 2.96 2.96 2.95

m 2(g) 3.13 4.12 3.13 3.12 3.13 3.14 3.14 3.14 3.15 3.14

m 3(g) 0.17 0.17 0.17 0.17 0.17 0.21 0.17 0.17 0.17 0.17

m 4(g) 0.26 0.26 0.25 0.26 0.27 0.30 0.26 0.26 0.26 0.26

m 5(g) 1.06 1.06 1.06 1.07 1.06 1.11 1.06 1.04 1.06 1.07

x' MonoG(ppm) 98.65 127.67 129.52 110.42 157.33 162.48 180.01 173.54 156.53 149.03

x' DiG(ppm) 696.73 730.57 719.12 659.12 638.75 600.99 595.94 576.69 551.82 515.26

x' TriG(ppm) 2623.62 2097.58 2213.91 2909.21 2292.99 1998.23 1653.25 1558.12 1489.17 1304.68

x' Glycerol(ppm) 5.66 7.19 11.45 26.16 80.49 106.41 144.77 175.22 194.13 199.18

x' FAMEs(ppm) 545.92 628.96 647.13 702.70 1329.47 1590.12 1993.37 2265.69 2442.12 2416.07

x MonoG 0.03 0.04 0.05 0.05 0.05 0.04 0.04 0.04 0.03 0.01

x DiG 0.07 0.15 0.13 0.11 0.09 0.08 0.08 0.08 0.07 0.01

x TriG 0.06 0.29 0.23 0.21 0.14 0.13 0.12 0.11 0.09 0.02

x Glycerol 0.00 0.01 0.02 0.02 0.03 0.04 0.04 0.05 0.05 0.01

x FAMEs 0.11 0.19 0.28 0.36 0.46 0.50 0.56 0.62 0.60 0.11

D-2

Figure 14: Mass fraction profile of reacting species in the reactor

Table 192: Conversion from xFAMEs to X

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

0 500 1000 1500 2000

Ma

ss F

ractio

n

Time (s)

Mono-Glyceride

Di-Glyceride

Tri-Glyceride

Glycerol

FAMEs

Time (s) x FAMEs X

48.00 0.11 0.13

138.00 0.14 0.17

224.00 0.14 0.16

439.00 0.25 0.30

582.00 0.31 0.38

878.00 0.38 0.45

1179.00 0.45 0.54

1512.00 0.49 0.59

1791.00 0.49 0.59

E-1

APPENDIX E LAB NOTEBOOK

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