research into biodiesel kinetics catalyst development · research into biodiesel kinetics &...

Research into Biodiesel

KINETICS

&

CATALYST DEVELOPMENT

By

Adam Karl KHAN

A thesis submitted to the Department of Chemical Engineering

In partial fulfilment of the requirements For an Individual Inquiry Topic at

The University of Queensland

Brisbane, Queensland, Australia

17 May 2002

Adam Karl KHAN Individual Inquiry A

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ACKNOWLEDGEMENTS I would like to thank my supervisor, Assoc Prof Victor Rudolph for firstly, giving me this opportunity have a part in this project and more importantly giving me support throughout both my previous and current work. I would also like to say that his faith in me has given me confidence in my ability to be an engineer. From this work I have begun to appreciate how a structured, directed and enthusiastic approach to projects such as this has many benefits, including success. I would also like to thank Dr Yinghe He for his continuing support and help throughout my time working on this project. He has given me much needed guidance when I have required it and tried unsuccessfully to teach me some Chinese, I also would like to thank Ms Allison Hanley for her assistance and input on cloudy issues and the many offers of much needed help in writing this thesis. Furthermore, I would like to say thanks to Mr Graham Kerven for guidance in gas chromatography and analytical chemistry. Finally I would like to thank my wife Fleur Khan and daughters Whitney and Isobel for their eternal support and understanding of my goals and aspirations. Without them I would not have been able to complete much of what I have done and become who I am. They are the light that shines my way and the drive for my ever persistent determination.


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ABSTRACT

Biodiesel is a cleaner burning fuel than diesel and a suitable replacement. It is made from non-toxic, biodegradable, renewable resources, such as new and used cooking oil, and animal fats. Fats and oils are chemically reacted with alcohols (ethanol was used in this work) to produce chemical compounds known as fatty acid ethyl esters (biodiesel). Glycerol, used in the pharmaceuticals and cosmetics industry along with many other applications, is produced in this reaction as a by-product. The relative high cost of refined oils, fats and production methods makes biodiesel more expensive than petroleum-derived fuel. It was found that the high consumption of catalyst and low yields of ethyl esters in conventual processing limits the use of crude feed stocks. Preliminary studies with crude feed stocks, such as crude tallow and used oils and several different catalysts provided some kinetic data on the transesterification reaction. This was achieved by conducting the reactions at various temperatures and reactant molar ratios. Although homogenous acid catalysed esterification is slower than alkali catalysed transesterification, at moderate temperatures, it is significantly increased at temperatures up to 240°C. Unlike current commercial processes, this reaction can make use of crude feedstocks and gives high yields, which have subsequently generated much interest. The data during this project was obtained in a pressurised batch reactor with the future intent of applying it to a continuous process with a heterogenous catalysts and crude feed stocks. In order to meet the detailed requirements for biodiesel fuel, gas chromatography coupled with a simple sample preparation step was developed to handle quantitative analysis of the product mixture. Although, this method analyses the full spectrum of products and is accurate, reliable, but a slightly expensive; new technology like Near Infrared Spectroscopy may offer inexpensive online analysis.


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TABLE OF CONTENTS

1.0 INTRODUCTION......................................................................................1 1.1 OBJECTIVES..............................................................................................1

1.1.1 Implementation ......................................................................................1

2.0 LITERATURE REVIEW .........................................................................2 2.1 SCOPE .........................................................................................................2 2.2 INTRODUCTION .......................................................................................2 2.3 BACKGROUND .........................................................................................2

2.3.1 Fats and Oils ..........................................................................................2 2.3.2 Biodiesel ................................................................................................4 2.3.3 Production Costs ....................................................................................4

2.4 PROCESS OVERVIEW..............................................................................5 2.4.1 Direct use and blending .........................................................................5 2.4.2 Viscosity ................................................................................................5 2.4.3 Microemulsions......................................................................................6 2.4.5 Thermal Cracking ..................................................................................6 2.4.6 Transesterification..................................................................................7 2.4.7 Saponification ........................................................................................7 2.4.8 Esterification ..........................................................................................8 2.4.9 Hydrolysis ..............................................................................................8 2.4.10 Aminolysis .............................................................................................9 2.4.11 Biocatalysts ............................................................................................9 2.4.12 Catalyst Free ..........................................................................................9 2.4.13 Supercritical Methanol...........................................................................9

2.5 COMPARATIVE ANALYSIS OF PROCESSES.....................................10 2.6 PROCESS OVERVIEW OF SEPARATION............................................10

2.6.1 Critical Analysis Literature..................................................................11 2.6.2 Heterogeneously Catalysed Process ....................................................11

2.7 PRODUCT ANALYSIS ............................................................................12 2.7.1 High Precision Liquid Chromatography..............................................13 2.7.2 Gas Chromatography ...........................................................................13 2.7.3 Near Infrared Spectroscopy .................................................................14

2.8 LITERATURE REVIEW CONCLUSION................................................14

3.0 EXPERIMENTAL...................................................................................15

3.1 REACTION METHODOLOGY ...............................................................15 3.1.1 Equipment ............................................................................................16 3.1.2 Reactants ..............................................................................................17 3.1.3 Conditions ............................................................................................17

3.2 ANALYSIS METHODOLOGY................................................................17 3.2.1 Standards..............................................................................................18 3.2.2 Procedure for stock standards ..............................................................18 3.2.3 Procedure for working standards .........................................................18 3.2.4 Procedure for samples..........................................................................18 3.2.5 Procedure GC application ....................................................................18 3.2.6 Typical Analysis Calculation...............................................................19 3.2.7 Equipment ............................................................................................20


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3.2.8 Reagents...............................................................................................21 3.2.9 Conditions ............................................................................................21 3.2.10 Safety ...................................................................................................21

4.0 RESULTS .................................................................................................22 4.1 REACTIONS .............................................................................................22 4.2 ANALYSIS................................................................................................23

5.0 DISCUSSION ...........................................................................................25 5.1 ANALYSIS................................................................................................25 5.2 ANALYSIS ERROR .................................................................................25 5.3 REACTIONS .............................................................................................25 5.3.1 Catalysts...............................................................................................26

6.0 CONCLUSIONS ......................................................................................26

7.0 FUTURE WORK AND RESEARCH ....................................................26

8.0 REFERENCES.........................................................................................28

APPENDIX A - Data for requested sample analysis ..............................................30

APPENDIX B - Data for requested sample analysis # 2 ........................................31

APPENDIX C – Tabulated data on experiments....................................................32

APPENDIX D - Tabulated data on experiments ....................................................33

APPENDIX E – Pressure Vs. Temperature for Water & Ethanol .......................34

APPENDIX F – Calibration curve for triglycerides...............................................35

APPENDIX G - Calibration curve for diglycerides................................................36

APPENDIX H - Calibration curve for monoglycerides .........................................37

APPENDIX I - Calibration curve for glycerol ........................................................38

APPENDIX J - Calibration curve for ethyl esters..................................................39


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LIST OF FIGURES Fig. 1. Diglyceride with two fatty acid groups ..............................................................3

Fig. 2. Transesterification of triglycerides with alcohol ...............................................7

Fig. 3. Saponification from free fatty acid.....................................................................8

Fig. 4. Saponification from ester ...................................................................................8

Fig. 5. Esterification ......................................................................................................8

Fig. 6. Hydrolysis of triglycerides .................................................................................9

Fig.7. Aminolysis of triglycerides ..................................................................................9

Fig.8. Typical flow chart of the process of esterification of lipids to biodiesel...........11

Figure 9. Tallow samples taken over 60min reacted with acid ...................................15

Figure 10. Parr reactor and PID controller................................................................16

Figure 11. Example of standards calibration curve ....................................................19

Figure 12. Low conversion with no catalyst, Valfor and Calcium carbonate respectively ................................................................................................22

Figure 13. Conversions vs. time for biodiesel run Bio0034 ........................................22

Figure 14. High conversion for Saveall tallow and rapeseed oil ................................23

Figure 15. Chromatogram for Bio0034 at 5min..........................................................24

Figure 16. Chromatogram for Bio0034 at 60min........................................................24

LIST OF TABLES Table 1. Typical chemical properties of vegetable oil (Groering et al., 1982*) ...........3

Table 2. Typical fatty acid composition - of common oil source (Kincs, 1985) ............4

Table 3. Comparison of typical properties of diesel, canola oil and biodiesel .............4

Table 4. Properties of ethyl ester and diesel control fuel* ............................................4

Table 5. Compositional data of pyrolysis of oils ( Ma 1999) ........................................6

Table 6.Comparison between production of biodiesel ................................................10

Table 7. List of potential catalysts ...............................................................................12

Table 8. Detailed requirements for biodiesel fuel* .....................................................13

Table 9. Typical reaction data sheet............................................................................16

Table 10. List of chemicals, supplier, quantity and grade...........................................17

Table 11. Molecular weight of lipids ...........................................................................17

Table 12. Stock standards ............................................................................................19

Table 13. Working standards.......................................................................................20

Table 14. Quantitative analysis of reactions ...............................................................23


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1.0 INTRODUCTION 1.1 OBJECTIVES Biodiesel presents a suitable renewable substitute for petroleum based diesel. The current production process for biodiesel is through a batchwise reaction, which disadvantages it because of high capital costs, labour intensity and difficult process and product quality control. An obvious method to avoid or minimise these difficulties is to use a continuous production process, to achieve this it is necessary to have a good knowledge of the chemical transformation reactions and their kinetics. Underlying this is the requirement to be able to analyse the conversion on a dynamic basis. This therefore permits the reaction conditions to be optimised. The primary objectives of this thesis are therefore to quantify the kinetics of the reaction with a batch reactor and develop a suitable analysis technique for this purpose. The literature review has shown that there are a variety of options for the production of biodiesel. These are all disadvantaged by raw materials that are high in free fatty acids and have a significant quantity of water present. There would be clear commercial advantages in being able to process low grade raw materials that are cost effective in a continuous process. These issues all arise due to the limitations associated with current catalysts. To take advantage of these further developments catalyst development needs to be achieved. This work addresses these as specific objectives;

a) test potential catalysts for their suitability and b) collect kinetic data on their subsequent reaction rates

This information will then be used for the development of a continuous process. A key requirement for a continuous process is a suitable heterogeneous catalyst that not only fulfils the high reaction rate requirements but also has features such as; insolubility in the reaction mixture, long working life, suitable particle size, high temperature resistance and a large surface area.

1.1.1 Implementation An analytical procedure that correctly quantified the products and extent of conversion represents the single most important requirement of this project. This was therefore accorded a very high priority. Nevertheless, developing an analytical procedure that routinely provided trustworthy and reproducible results, presented a significant hurdle which consumed the major part of the project program. A plug flow continuous reactor is correctly simulated by a batch reactor, and this provides a convenient means for screening reactions for preparation of their use in a plug flow tubular reactor. Batch experiments typically took two hours to conduct; analytical preparations took approximately five hours. This limited the total number of experiments that could feasibly be conducted in the period available.


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2.0 LITERATURE REVIEW 2.1 SCOPE This literature survey discusses the benefits of using biodiesel as a suitable diesel substitute, whilst briefly touching on the history behind alternative compression engine fuels. It discusses some of the more current manufacturing techniques for the production of biodiesel as well as some new technology that is being researched. This is primarily focusing on developments in catalyst application, problems associated with different catalysts and the benefits of various catalyst systems. The area of downstream processing is briefly discussed, however separation is outside the focus of this work. Some critical analysis is discussed on the pros and cons of different systems and details of the analysis methods available and why and why not they are implemented in this work. Finally there is a discussion section and recommendation for further research section that highlights the areas in this research that are in need of further development.

2.2 INTRODUCTION With the exception of hydroelectricity and nuclear energy, the majority of the worlds energy needs are supplied through petrochemical sources, coal and natural gas. All of these sources are finite and at current usage rates will be consumed by the end of the next century (Aksoy, 1990). The depletion of world petroleum reserves and increased environmental concerns has stimulated recent interest in alternative sources for petroleum-based fuels. Biodiesel has arisen as a potential candidate for a diesel substitute due to the similarities it has with petroleum-based diesel.

2.3 BACKGROUND

2.3.1 Fats and Oils The use of vegetable oils as alternative fuels has been around since 1900 when the inventor of the diesel engine Rudolph Diesel first tested them, in his compression engine (Foglia, Jones, Haas, & Scott, 2000). To date there have been many problems found with using vegetable oils directly in diesel engines (especially in direct injection engines). These include (Ma, 1999):

1. Coking and trumpet formation on the injectors to such an extent that fuel atomisation does not occur properly or is even prevented as a result of plugged orifices,

2. Carbon deposits, 3. Oil ring sticking, 4. Thickening and gelling of the lubricating oil as a result of

contamination by vegetable oils, and 5. Lubricating problems.

Other disadvantages to the use of vegetable oils and especially animal fats, are the high viscosity (about 11 to 17 times higher than diesel fuel), lower volatilities content which causes the formation of deposits in engines due to incomplete combustion and incorrect vaporisation characteristics. Table 1 shows the percentages of unsaturated fatty acids in some typical oils, the degree of saturation is dictated by the number of double bonds in the fatty acids e.g. 18:01 denotes a carbon length of 18 with on double bond. At high temperatures there can be some problems with polymerisation


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of unsaturated fatty acids, this is where cross linking starts to occur between other molecules, causing very large agglomerations to be formed and consequently guming occurs (Pryde, 1983). This problem does not occur with fats as they have a very low concentration of unsaturated fatty acids as can be seen in table 2. Ethanol can be used as an additive to improve these properties, but pure vegetable oils are rarely used for a straight diesel fuel substitute. Ethanol as an additive or a reactant is often preferred in place of other simple alcohols, such as methanol because it is less toxic and because it is easily produced from renewable sources such as biomass or grains (Foglia et al., 2000). Fats, due to their high melting point and viscosity, can not be used directly in diesel engines or mixed with diesel fuels. The degree of saturation of the fatty acids attached to the glycerol backbone determines the boiling point of the triglyceride. As such, compared with oils, little research has been done on their potential as diesel fuel. Some typical composition of fats and oils can be found in tables 1& 2 (Ma, 1999). Fats and oils are primarily composed of triglycerides, esters of glycerol (mono- & diglycerides) and fatty acids (carboxylic acids). The term monoglyceride or diglyceride refers to the number of fatty acids that are attached to the glycerol backbone i.e. a diglyceride would have one hydroxyl group and two fatty acid groups attached to the glycerol backbone as in figure 1.

CH2

CH2

CH

Diglyceride

COO R

COO R

C OH

O

Fig. 1. Diglyceride with two fatty acid groups

Table 1. Typical chemical properties of vegetable oil (Groering et al., 1982*) Fatty acid composition, % by weight

Palmitic Stearic Oleic Linoleic Linolenic arachidic Vegetable oil 16:00 18:00 18:01 18:02 18:03 20:00 Acid*Value Corn 11.67 1.85 25.16 60.6 0.48 0.24 0.11 Cottonseed 28.33 0.89 13.27 57.51 0 0 0.07 Crambe 2.07 0.7 18.86 9 6.85 2.09 0.36 Peanut 11.38 2.39 48.28 31.95 0.93 1.32 0.2 Rapeseed 3.49 0.85 64.4 22.3 8.23 0 1.14 Soybean 11.75 3.15 23.26 55.53 6.31 0 0.2 Sunflower 6.08 3.26 16.93 73.73 0 0 0.15


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Table 2. Typical fatty acid composition - of common oil source (Kincs, 1985) Fatty acid composition, % by weight

Lauric Myristic Palmitic Stearic Oleic Linoleic Linolenic Lipid 12:00 14:00 16:00 18:00 18:01 18:02 18:03 Soybean 0.1 0.1 10.2 3.7 22.8 53.7 8.6 Cottonseed 0.1 0.7 20.1 2.6 19.2 55.2 0.6 Palm 0.1 1 42.8 4.5 40.5 10.1 0.2 Lard 0.1 1.4 23.6 14.2 44.2 10.7 0.4 Tallow 0.1 2.8 23.3 19.4 42.4 2.9 0.9 Coconut 46.5 19.2 9.8 3 6.9 2.2 0

2.3.2 Biodiesel Subsequent research found that triglycerides could be converted into simple alkyl fatty acid esters (Biodiesel) which has similar properties to diesel see table 3 & 4. The first documented commercial production of rapeseed oil methyl esters is reported to be in 1988 (Korbitz 2001). To date biodiesel production can be found in over 28 countries of which Germany and France are the world’s largest [Kusdiana, 2002].

Table 3. Comparison of typical properties of diesel, canola oil and biodiesel Diesel Canola Biodiesel Density (kg/L) 0.835 0.922 0.88 Gross calorific value (MJ/L) 38.3 36.9 33.3 Viscosity ( @ 37.8°C) 3.86 37 4.7 C:H:O ( ratio ) 3.59 3.26 2.38 Sulphur (%) 0.15 0.0012 <0.01

Source: Adapted from Table 6.1 of BTCE (1994) and from www.afdc.doe.gov . The C:H:O ratio for biodiesel is taken from http://www.biodiesel.org/fleets/summary.shtml#attributes

Table 4. Properties of ethyl ester and diesel control fuel* REE (Rapeseed Ethyl Ester). Diesel Gross heat of combustion (MJ/kg) 40.5 45.2 Flash Point °C 124 82 Cloud Point °C -2 -14 Pour Point °C -10 -21 Viscosity cs @ 40°C 6.17 2.98 Cetane Number 59.7 49.2 *Based on analysis by Phoenix Chemical Lab, Inc. and the Agricultural Engineering Analytical Laboratory, University of Idaho. REE

Biodiesel has many benefits such as it is biodegradable, non-toxic, has a low emission profile (including potential carcinogens) and is a renewable resource (Ma, 1999). European biodiesel is typically made from rapeseed oil and methanol, whereas in the US it is predominately made from soybean oil. This reflects the agricultural practices of the two regions.

2.3.3 Production Costs The greatest hurdle in commercialisation of biodiesel is the cost of production. Currently, raw material costs and the cost of production are keeping the retail price of biodiesel too high for it to be an option for many users. The current method of production is with large batch reactors. Raw materials generally consist of methanol

smm /2


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and high-quality vegetable oils. Only approximately 55% of the US biodiesel industry can use any fat or oil feedstock, the remainder is limited to refined vegetable oils, the least expensive of which is soy bean oil. Although the production of biodiesel is now conducted on a large scale, there are still many problems with using crude feed stock (Ma, 1999). Until these problems are resolved with measures such as a continuous process and the use of crude oils waste fats, such as used cooking oils and abattoir fats, the cost of production will remain relatively high. The recovery of high quality glycerol, a by-product which is required for many other processes, would also contribute to substantially reducing production costs. The European Union has set an objective to secure for motor biofuels a market share of 5% of total motor fuel consumption by 2005 (a significant amount of this will be biodiesel). The US Department of Energy estimates that up to 50% of the total diesel fuel consumption could be replaced with biodiesel. US production of biodiesel, from both fats and oils is currently approximately 7.12 billion litres ( Alcantara 2000).

2.4 PROCESS OVERVIEW There are several generally accepted ways to make biodiesel some more common than others, e.g. blending and transesterification, and several others that are more recent developments .e.g. reaction with supercritical methanol. An overview of these processes is as follows;

1. Direct use and Blending, which is the use of pure vegetable oils or the blending with diesel fuel in various ratios,

2. Microemulsions with simple alcohols, 3. Thermal Cracking (pyrolysis) to alkanes, alkenes, alkadienes etc 4. Transesterification (alcoholysis) which consists of several sub categories;

i. esterification , ii. saponification,

iii. hydrolysis (reaction with water) and iv. aminolysis (reaction with amines)

5. Other forms of catalysis i. biocatalysts

ii. reaction with supercritical methanol iii. catalyst free

2.4.1 Direct use and blending The direct use of vegetable oils in diesel engines is problematic and has many inherent failings. It has only been researched extensively for the past couple of decades, but has been experimented with for almost a hundred years. Although some diesel engines can run pure vegetable oils engines, turbocharged direct injection engines such as trucks are prone to many problems (BTCE, 1994). Energy consumption, with the use of pure vegetable oils, was found to be similar to that of diesel fuel (Hemmerlein et al. 1991). For short term use ratios of 1:10 to 2:10 oil to diesel have been found to be successful (Ma, 1999). The difficulties may be grouped into three key areas:

2.4.2 Viscosity As can be seen from table 3 the properties of canola oil and diesel are very similar, except a significant difference in viscosity, with canola oil having twelve times the viscosity of diesel. Even after heating to around 80°C it is still six times as viscous as diesel. This leads to problems with flow of oils from the fuel tank to the engine,


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blockages in filters and subsequent engine power losses. Even if preheating is used to lower the viscosity, difficulties may still be encountered with starting due to the temperatures required for oils to give off ignitable vapours. Further, engines can suffer coking and gumming which leads to sticking of piston rings due to multi-bonded compounds undergoing pyrolyses. Polyunsaturated fatty acids also undergo oxidation in storage causing gum formation and at high temperatures where complex oxidative and thermal polymerisation can occur ( Ma 1999).

2.4.3 Microemulsions Microemulsions are defined as a colloidal equilibrium dispersions of optically isotropic fluid microstructures, with dimensions generally in the 1-150 nm range. These are formed spontaneously from two normally immiscible liquids and one or more ionic or non-ionic amphophiles (Schwab et al., 1987). A microemulsion is designed to tackle the problem of the high viscosity of pure vegetable oils by reducing the viscosity of oils with solvents such as simple alcohols. The performances of ionic and non-ionic microemulsions where found to be similar to diesel fuel, over short term testing. They also achieved good spray characteristics, with explosive vaporisation which improved the combustion characteristics (Ma, 1999). In longer term testing no significant deterioration in performance was observed, however significant injector needle sticking, carbon deposits, incomplete combustion and increasing viscosity of lubricating oils where reported ( Ma, 1999).

2.4.5 Thermal Cracking Pyrolysis is the conversion of one substance into another by means of applying heat i.e. heating in the absence of air or oxygen with temperatures ranging from 450°C – 850°C (Sonntag, 1979b). In some situations this is with the aid of a catalyst leading to the cleavage of chemical bonds to yield smaller molecules (Weisz et al., 1979). Unlike direct blending, fats can be pyrolyised successfully to produce many smaller chain compounds. The pyrolysis of fats has been investigated for over a hundred years, especially in countries where there is a shortage of petroleum deposits. Typical catalyst that can be employed in pyrolysis are 2SiO and 32OAl . The ratios of light to heavy compounds are temperature and time dependent. Typical breakdown of compounds found from pyrolyisis of safflower and soybean oil, are listed in table 5. Table 5. Compositional data of pyrolysis of oils ( Ma 1999)

Percent by weight *HO Safflower Soybean Alkanes 40.9 29.9 Alkenes 22 24.9 Alkadienes 13 10.9 Aromatics 2.2 1.9 Unresolved unsaturates 10.1 5.1 Carboxylic acids 16.1 9.6 Unidentified 12.7 12.6 *HO High Oleic Safflower oil

The equipment for pyrolysis or thermal cracking is expensive for modest throughputs. Although, the products are chemically similar to pyrochemically based diesel, oxygen removal from the process decreases the products benefits of being an oxygenated fuel. This decreases its environmental benefits and generally produces more fuel similar in properties of gasoline than diesel, with the addition of some low value materials.


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2.4.6 Transesterification Transesterification is the reaction of a lipid with an alcohol to form esters and a by-product, glycerol. It is in principle the action of one alcohol displacing another from an ester, the term alcoholysis (cleavage by an alcohol).The reaction, as shown in figure 2 is reversible and thus an excess of alcohol is usually used to force the equilibrium to the product side. The stoichiometry for the reaction is 3:1 alcohol to lipids; however in practice this is usually increased to 6:1 to increase product yield. A catalyst is usually used to speed up the reaction and may be basic, acid or enzymatic in nature (Ma, 1999). The alkalis that are generally used include NaOH, KOH, carbonates and corresponding sodium and potassium alkoxides such as sodium methoxide, ethoxide, propoxide and butoxide. Sodium hydroxide is the most common alkali catalyst that is used, due to economical reasons and availability. Alkali-catalysed reactions are used more often commercially than acid catalysts, as the reactions are faster. Only simple alcohols can be used in transesterification such as, methanol, ethanol, propanol, butanol and amyl alcohol. Methanol is most often used for commercial and process reasons related to its physical and chemical nature (shortest chain alcohol and is polar). However ethanol is becoming more popular as it is a renewable resource and does not raise the same toxicity concerns as methanol (Ma, 1999). The type of catalyst, the reaction conditions and the concentration of impurities in a transesterification reaction determine the path that the reaction follows. For alkali catalysed transesterification, water and FFA are not favourable to the reaction, so anhydrous triglycerides and alcohol are necessary to minimise the production of soap. Soap production decreases the amount of esters and renders the separation of glycerol and esters difficult. In current commercial processes using crude feed stock, excess alkali is added to remove all the FFAs.

OHCH2

OHCH2

OHCH

COOR1 R'

COOR2 R'

COOR3 R'

CH2

CH2

CH

COO R1

COO R2

COO R3

GlycerolEstersTriglyceride

++ 3R'OHCatalyst

Simple Alcohol Fig. 2. Transesterification of triglycerides with alcohol

2.4.7 Saponification The production of soap sometimes called alkaline hydrolysis, converts triacylglycerols to glycerol and a mixture of salts of long-chain carboxylic acids. As can be seen from figures 3 & 4, the reaction can be carried out with an ester (i.e. triglycerides) or with carboxylic acids (i.e. free fatty acids). However, the production of fatty acids is an intermediate step when triglycerides are directly used for saponification. The commercial production of soap is usually conducted in two phases. The first phase is the conversion of lipids into FFAs by boiling with aqueous sodium hydroxide until hydrolysis is complete and then adding sodium chloride to precipitate the soap (Solomon, 1996).


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R C OH

O

+ NaOH R C O-Na+

O

H2O

WaterSaltFree Fatty Acid Metalic alkoxide

Heat+

Fig. 3. Saponification from free fatty acid

or

R C OR'

O

+ NaOH R C O-Na+

O

R'OH

Simple AlcoholSaltEster Metalic alkoxide

Water+

Fig. 4. Saponification from ester

2.4.8 Esterification The formation of esters occurs through a condensation reaction known as esterification. This requires two reactants, carboxylic acids (fatty acids) and alcohols. (Solomon, 1996). Esterification reactions are acid catalysed and proceed slowly in the absence of strong acids such as sulphuric acid, phosphoric acid, organic sulfonic acids and hydrochloric acid. The equation for and esterification reaction can be seen in figure 5.

R C OH

O

R'OH+H+

R C OR'

O

+ H2O

WaterEstersFree Fatty Acid Simple Alcohol Fig. 5. Esterification

2.4.9 Hydrolysis The hydrolysis of lipids forms a heterogenous reaction system made up of two liquid phases. The disperse aqueous phase consists of water and glycerol; the homogenous lipid phase consists of fatty acids and glycerides. The hydrolysis of glycerides takes place in the lipid phase in several stages via partial glycerides (diglycerides and monoglycerides) (Ullmann’s, 1987). Acid catalysts are very effective at accelerating the hydrolysis reaction. However, at high temperatures substantial material corrosion occurs. Diabasic metal oxides have a higher activity than more strongly alkaline monobasic metal oxides. Zinc oxide in its soap form has been suggested to be the most active catalyst for hydrolysis reactions (Ullmann’s, 1987). Reaction without a catalyst is not economical below 210°C, thus requiring the implication of high temperature, pressure techniques. Modern continuous plants operate at pressures between 0.6-1.2 MPa at 210-260°C without a catalyst. This increased pressure allows the mutual solubility of the two phases to increases to a point where the formation of continuous phase occurs.


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OHCH2

OHCH2

OHCH

COOR1 H

COOR2 H

COOR3 H

CH2

CH2

CH

COO R1

COO R2

COO R3

GlycerolEstersTriglyceride

+Heat3H2O

Water

+

Fig. 6. Hydrolysis of triglycerides

2.4.10 Aminolysis Esters undergo nucleophilic substitution at their acyl carbon atoms when they are treated with primary or secondary amines. These reactions are slow but are synthetically useful (Solomon, 1996).

H N R5

R4

Amine

OHCH2

OHCH2

OHCH

CH2

CH2

CH

COO R1

COO R2

COO R3

GlycerolTriglyceride

+Heat+

N R5R4

R1 C

O

N R5

R4

R3 C

ON R5R4

R2 C

O

Amides

3

Fig.7. Aminolysis of triglycerides

2.4.11 Biocatalysts Biocatalysts are usually lipases; however conditions need to be well controlled to maintain the activity of the catalyst. Hydrolytic enzymes are generally used as biocatalysts as they are ready available and are easily handled. They are stable, do not require co-enzymes and will often tolerate organic solvents. “Their potential for regioselective and especially for enantioseletive synthesis makes them valuable tools” [Schuchardt, 1998]. Recent patents and articles have shown that reaction yields and times are still unfavourable compared to base-catalysed transesterification for commercial application.

2.4.12 Catalyst Free Transesterification will occur without the aid of a catalyst, however at temperatures below 300°C the rate is very low. It has been said that there are, from a broad perspective, two methods to producing biodiesel and that is with and without a catalyst.

2.4.13 Supercritical Methanol The study of the transesterification of rapeseed oil with supercritical methanol was found to be very effect and gave a conversion of >95% within 4min. A reaction temperature of 350°C, pressure of 30MPa and a ratio of 42:1 of methanol to rapeseed oil for 240s were found to be the best reaction conditions. The rate was substantially high from 300 to 500°C but at temperatures above 400°C it was found that thermal degradation takes place. Supercritical treatment of lipids with a suitable solvent such as methanol relies on the relationship between temperature, pressure and the thermophysical properties such as dielectric constant, viscosity, specific weight and


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polarity (Kusdiana, 2000). A comparison of supercritical methanol production and alcoholysis can be seen in table 6.

2.5 COMPARATIVE ANALYSIS OF PROCESSES There are several problems associated with the production of biodiesel with alkali homogenous catalysts. The batch process is time consuming, as purification of the product for catalyst and saponified products is necessary. There is also the problem of immiscible phases of the lipid and alcohol, which requires vigorous stirring to enable good contact of reactants for the reaction to occur (Kusdiana, 2000). In the base-catalysed transesterification method use of crude lipids that contain large quantities of FFA leads to catalyst destruction. It is suggested that the concentration of FFA be as low as possible, not exceeding 0.5%.

Table 6.Comparison between production of biodiesel

Common Method *SC MeOH method Reaction Time 1-6h 0.067h Reaction Condition 0.1MPa, 30-65°C 35MPa, 350°C Catalyst acid or alkali none Free Fatty Acids Saponified products methyl esters Yield 97% (normal) 98.50% Removal for Purification

methanol, catalyst and saponified products

methanol

Process Detailed Simple *SC MeOH method - Supercritical Methanol

2.6 PROCESS OVERVIEW OF SEPARATION Although not within the scope of this report, separation is an integral part of the production of biodiesel and therefore some basic concepts will here within be covered. The refining of the products from the production of biodiesel can be technically difficult and can substantially increase the cost of production. The purity of biodiesel must be high and generally conform to international standards such as the European Union (EU) standards for alternative fuels. Under the EU standards for alternative diesel fuels free fatty acids, alcohol, free and bound glycerin and water content must be kept to a minimum and the fuel must be at least greater than 96.5% pure (Karaosmanoglu, 1996). The typical product mixture of a transesterification reaction contains fatty acid esters (biodiesel), monoglycerides, diglycerides, glycerol, alcohol and catalyst, in varying concentrations. The primary goal is the removal of the esters from the mixture, maintaining low costs and ensuring a high purity product. Glycerol in its pure form is seen to be a secondary product of the reaction as it can be sold to various industries. To keep the cost of production competitive, the removal and resale of glycerol is essential. The remaining mixture contains by-products and alcohol that should have minimal contaminants if the conversion is high, except for the alcohol which would be distilled off.


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Alcohol

Lipids

CatalystMineral

Acid

AlcoholRecovery

Reactor Settler Washing Purification Evaporation

NeutralisationDistillation

Settler Evaporation

Biodiesel

Glycerol

FattyAcids

~

~~

~

Fig.8. Typical flow chart of the process of esterification of lipids to biodiesel

If the reaction has reached a high level of conversion the product mixture will form two liquid phases, with a solid phase if a solid catalyst has been used. The bottom phase of the mixture would consist of glycerol and the top phase alcohol and esters. In a reaction that did not reach full conversion the unreacted lipids and bound glycerol would solidify in the bottom layer, as can be seen in figure 12. For molar ratios greater than 5.67 of MeOH it was reported that there are some difficulties in separating glycerin from methanol (Kusdiana, 2000).

2.6.1 Critical Analysis of the Literature There where only two papers found that made mention of heterogenous catalysts. Of these there were 3 potential catalysts of which only one showed any promise. There is a distinct lack of information or research conducted on heterogenous catalysts. There are several references to co-solvents, however none make mention of biodiesel itself. The references to THF reported that it was suitable as a co solvent claiming it to be a low toxic compound, when the MSDS from Chemwatch showed it to have a high level of toxicity. There was little mention of the thermal degradation of products such as glycerol and triglycerides, particularly as glycerol degrades to a highly toxic compound, acrolein. Generally analysis techniques focused on glycerol and unconverted triglycerides, there was no mention of any residual components such as alcohol. This seems to be due to the currently accepted practice of extensily washing the product before analysis. Testing and quality control seems to focus on downstream fuel that is ready for retail sales, not necessarily testing for optimisation purposes. There is conflicting information on the impact of contaminants such as FFA and water. Some papers have said that water has a negative effect on the reaction and others have implied that acid catalysed reactions are not effected.

2.6.2 Heterogeneously Catalysed Process The use of hydrogenized guanidine’s on organic polymers as a catalyst for the transesterification of vegetable oils has been tested by Schuchard et al (1997). Principle tests conducted in a continuous reactor were promising and resulted in a patent (P93246, 1984). However there still appear to be some problems with this technique. For example, catalyst activity seems to deteriorate after an hour of operation (Schuchardt, 1998). This resulted in incomplete reaction and subsequent difficulties in phase separation. Irreversible protonation of the catalyst or catalyst leaching are a possible cause, however no definite test to confirm this had been conducted (Schuchardt, 1998).


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Experiments conducted by Suppes et al (2000) indicate that CaCO3 may be suitable for use as a heterogeneous alcoholysis catalyst. Preliminary batch experiments used beef tallow or soybean oil as the triglyceride source and diethylene glycol (DEG) as the alcohol. Subsequent attempts to verify these results where conducted using a similar batch apparatus but as yet have failed to replicate those results obtained by Suppes et al. There is only one difference in the experimental procedure used to replicate Suppes’s work which was the source of the 3CaCO , which was not sourced from Lancaster (Windham, NH). Trials conducted using CaO and 2)(OHCa as the catalyst also appear to have failed to achieve significant conversion. Although, this has not been confirmed with GC analyses, the physical appearance of the samples very much favours a high content of lipids thus subsequent low conversion. CaO is documented as being an effective heterogeneous alcoholysis catalyst and is in common use for monoglycerides(which would be solids at room temperature) production at temperatures ranging from 200oC to 220oC with reaction times of 1 to 4 hours (Suppes, 2001). The apparent failure CaCO3 as an alcoholysis catalyst may have been due to thermal degradation considering the high temperatures that the experiments were conducted under (>2200C). Other factors that require investigation include the role of glycerolises, polymerisation and hydrolysis and the effect of high concentrations of free fatty acids. Certain carbonate systems are also known to promote glycerolisis however the overall effect this would have under these reaction conditions is not yet known. Glycerolisis is the reaction of glycerol with triglycerides to form monoglycerides.

Lancaster (Windham, NH) Iowa Limestone Co. (Des Moines, IA) The calcium carbonate catalyst could function as a simple Bronsted base catalyst. The double bond migration, observed in the Na2CO3 and K2CO3 catalysed reactions, indicated that at these reaction temperatures the carbonate anion is an extremely strong base, however this has not been proven.

2.7 PRODUCT ANALYSIS Biodiesel can be significantly contaminated with both free and bound glycerol, triglycerides and alcohol due to incomplete transesterification and or insufficient purification. As noted in literature, the presence of these minor contaminates can be

Table 7. List of potential catalysts 4)(ORTi - Titanium IV alkoxides

OSnHC 22712 )( - bis(tri-n-butyltin)oxide - Organometallic tin complexes

32CONa - (Solubility of some of these?)

32COK

3ZnCO

3MgCO

3CaCO ZnO - supported on alumina

COOCaCH 3 - acetates of calcium and barium COOBaCH 3 (Salts or esters of ethanoic acid)


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detrimental to both engines and the environment through pollution. There are currently limits on the levels of these compounds in biodiesel that are set out in guidelines such as American Society for Testing and Materials (ASTM) which can be found in table 8. Over the past ten years there have been various investigations into methods to investigate the analysis of biodiesel, its impurities and by-products. The list includes Gas Chromatography (GC) distillation, solid phase separation, thin film liquid chromatography (TLC), High Precision Liquid Chromatography (HPLC), Refractometry, Near Infrared Spectroscopy with a Fibre-Optic probe (NIR) and Thin layer chromatography/flame-ionisation detection (TLC/FID) with an Iactroscan instrument [Plank, 1995, Freedman et al 1984]. The analysis technique needs to be accurate, reliable, reproducible, relatively quick and simple, and require equipment that is readily available. Formally HPLC, but more commonly now GC analysis is by far the most accepted methods for the analysis of biodiesel fuels (Knothe, 1998). The reasons behind this are simplicity, (once the system has been set up) and the high level of accuracy with which the results can be obtained (Plank, 1995).

Table 8. Detailed requirements for biodiesel fuel*

Property Test Method Limits Units Flash Point (closed cup) D93 100 min °C Water sediment D2709 0.05 max %Vol

Kinematic Viscosity D445 1.9-1.6 smm /2 Sulphated ash D874 0.02 max % mass Sulphur D2622 0.05 max % mass Copper strip corrosion D130 No. 3 max Cetane number D613 40 min Cloud Point D2500 RTC °C Carbon residue D4530 0.05 max % mass Acid number D664 0.8 max mg KOH/g Free glycerol F 0.02 % mass Total glycerine F 0.24 % mass *As out lined in ASTM PS-121 99

2.7.1 High Precision Liquid Chromatography Mittelbach & Trathnigg detailed a method that is similar to GC in that the samples require derivatisation. This was using HPLC coupled with isocratic separation, such as differential refractometry or density detection. There where some problems associated with separation according to molecular mass and hydroxyl content, but where over come by using a combination of a GPC-column set and a polar column in series [Trathnigg, 1990]. Free fatty acids and glycerol where separated from the mixture before the analysis was carried out and it was said that the analysis time was approximately 20 minutes.

2.7.2 Gas Chromatography The method proposed by Plank and Lorbeer using capillary gas chromatography, can provide qualitative and quantitative information about the concentrations of contaminants in biodiesel. The method is appropriate for measuring minor and major components in a sample, gives a high reliability of results, has simple instrumentation, requires a small amount of sample preparation and has a short analysis time (Plank, 1995).


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2.7.3 Near Infrared Spectroscopy Near Infrared Spectroscopy (NIR) is becoming a preferred method for quality control of biodiesel fuel. Due to its operational ease, rapidity of measurement and non-destructiveness it can be implemented as an online assessment of conversion in the transesterification reaction. The NIR method is less sensitive than GC for quantifying minor components, but can be used in combination with GC analysis for a higher level of analysis. However, that being said it is accurate to the point that it can be used in qualifying online conversion rates and major component concentrations. Standards’ testing for biodiesel is time consuming and costly, but can be superseded by NIR which would significantly reduce both the cost and the time of testing (Knothe, 1998). The determination of glycerol after water extraction was described by Bondioli et al (Plank, 1995). This would involve the extraction of glycerol from biodiesel into an aqueous phase which has been shown to be highly effective. Glycerol has a high affinity for water, very low for methyl esters, moderate for monoglycerides and small for diglycerides. Solubility of glycerol in methyl esters is low in the order of 0.15% and in the presence of a large amount of water is negligible (Van Gerpen, 1996). The glycerol free mixture would then be analysed via GC or HPLC. Another method is the Conradson carbon residue, sulphate ash and phosphorous content. This involves the combustion of a sample and subsequently weighed to reveal the mass of carbon, although quit crude it is accepted as a quick estimate of the conversion in transesterification (Hodl, 1994).

2.8 LITERATURE REVIEW CONCLUSION To date there has been extensive research into the area of the derivitisation of triglycerides for utilization in diesel engines. The development of a continuous reactor would greatly improve the economic viability of biodiesel as an alternative fuel source to petrochemical derived products. As a result of recent changes in eating patterns, there is an increasing surplus of animal fats that cannot be consumed by the soap industry. Companies are increasingly interested in this as an energy source to be combusted in furnaces for grid energy production. Large-scale production (i.e. continuous reactor) would be required for this to be viable. The development of such a facility would require extensive research into the kinetics of tallow derived biodiesel production as opposed to the well-documented kinetics of vegetable oil derived biodiesel.


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3.0 EXPERIMENTAL 3.1 REACTION METHODOLOGY In order to maintain a liquid reaction mixture under elevated temperatures, the mixture was subjected to high pressures following thermodynamic principles of the pressure temperature relationship. Calculations for the pressure temperature curve where done with ethanol being the most volatile component. A plot of pressure vs. temperature was used to calculate the maximum possible temperature as the pressure reactor was rated to 70bar. The calculation for the excess ethanol was done using the following correlations;

1. Ideal-gas equation 2. Generalised compressibility factor 3. Generalised virial-coefficient correlation

See Appendix A for pressure vs. temperature chart Thirty six reactions were carried out over the entire duration of the project and where recorded as can be seen in Appendix C and D. The conditions such as reactants, temperature, concentration, time and catalyst, where varied to assess firstly the catalyst activity and secondly the best possible conditions. The procedure that was used for each reaction is as follows;

1. The temperature of the tallow was raised to 65°C (melting point) if oil was used this is not necessary,

2. the required quantity of ethanol was weighed out in a beaker, 3. the catalyst was then added, 4. this was stirred whilst adding the tallow, and 5. then the mixture was quickly and completely mixed by stirring and then added to the

reactor. 6. Once the reactor lid was secured nitrogen was used to purge the oxygen from the

headspace. 7. The controller was then started and at 80°C the stirrer on the reactor was turned on.

In some cases samples where taken every 5 min and this was done through a sampling point with a ‘Khan-Guinness’ sampler system. The samples where then placed in an ice bath until required for analysis.

Figure 9. Tallow samples taken over 60min reacted with acid


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Table 9. Typical reaction data sheet Date Batch # Reactor Vessel 07/0402 Bio0036 Reactor Run Reactants: Mass g Mol Molecular Weight Prime Tallow 150.0 0.177 847.40 EtOH 48.91 1.062 46.05 H2SO4 3.98 0.0406 98.07 Reaction Conditions: Temperature 240°C Pressure 70 bar Time 60 min Comments: 6:1 Mole ratio of ethanol to oil ,2% catalyst by weight ,Calculation for vapour space 33g required extra for 240°C at 70bar, Total EtOH 81.91g

Some reactions where also carried out in beakers in the fume cupboard, although this takes a great deal longer to complete due to a decreased temperature, it is still a valuable tool to qualitatively asses a catalyst. The beaker reactions are carried out very similarly to those conducted in the pressure reactor, however they are heated via a heating element that has a magnetic stirrer. The beaker has a rubber stopper as a lid and evaporation of ethanol does occur at a rate that has not yet been determined.

3.1.1 Equipment The reactor was a Parr 2100 series 300ml pressure reactor. It was rated to 70bar and 100°C without cooling and 500°C with cooling. It has a programmable PID controller that can be seen in figure 10.

Figure 10. Parr reactor and PID controller


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3.1.2 Reactants The reactants used are listed in table 10. Table 11 lists the theoretical composition of beef tallow and rapeseed oil based on average fatty acid compositions and concentration of free fatty acids.

Table 10. List of chemicals, supplier, quantity and grade Chemical Grade Source Quantity Calcium Carbonate AR 99% Univar 500g Potassium Hydroxide AR 85% Chem Supply Pty Ltd 500g Anhydrous Ethanol AR 99% University Chemical Store 1.5L Sulphuric acid AR 98.2% source unknown 500ml Calcium Oxide unknown BDH Chemicals 500g Valfor unknown QA Australia 500g Beef Tallow Beef City 60Kg Prime Triglycerides 100% 30Kg

Save All FFA 44% Triglycerides 56% 30Kg

3.1.3 Conditions Reaction conditions can be found in Appendix C and D

3.2 ANALYSIS METHODOLOGY The product mixture contains a myriad of compounds with varying degrees of physical characteristics and chemical reactivity. It was preferable that the analysis method chosen could analysis the entire mixture simultaneously. This is quite a difficult task and required extensive research to find a suitable method. It was found that gas chromatography with sample pre-treatment was suitable and reliable. Troublesome compounds for GC analysis are those that have hydroxyl groups and are physically large i.e. free and bound glycerine and triglycerides. In the case of the hydroxyl groups, silylation (Trimethylisation) was employed to derivatise free and bound glycerine. This converts any hydroxyl groups into trimethylsilyl ether groups -

3)3OSi(CH , which are more volatile and do not interact with the stationary phase of the capillary column. The interaction between the hydroxyl groups and the column is a chemical one, but the triglycerides are simply very heavy and have a low volatility. To overcome this physical interaction the maximum temperature for the column must be exceeded in

Table 11. Molecular weight of lipids Oil Tallow % as triglycerides FFA % as triglycerides FFA Palmitic 16:0 256.41 3.49 8.94 0.28 71.79 Stearic 18:0 284.47 0.85 2.41 0.22 62.58 Oleic 18:1 281.46 64.4 181.26 0.45 126.65 Linoleic 18:2 279.45 22.3 62.31 0.03 8.38 Linolenic 18:3 277.43 8.23 22.83 0 0 Myristic 14:0 229.35 0 0 0.02 4.58 Average molecular weights 847.40 277.77 836.09 274.01 Triglycerides Prime 847.40 ~100% Triglycerides SaveAll 588.82 44% FFA and 66% Triglycerides Rapeseed Oil 847.40


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order to elute the triglycerides in an acceptable timeframe. Although this is not recommended by the manufacturer as an acceptable practice, it is necessary for this project. It will do long term damage to the column, by degrading the stationary phase known as ‘bleeding’, but in the short term this will not substantially effect the results. Any compounds that are not eluted on each run will tend to exit the column on subsequent runs as ‘ghost peaks’. This is where an unknown peak will appear in the chromatogram either by concealing other peaks or as a standalone. Therefore for this reason and that of quantitatively analysing and reproducing the results, there where effectively three stages to sample analysis. These are standards preparation and calibration of each homogenous series, sample preparation and the actual GC analysis.

3.2.1 Standards Tables 12 and 13 outline the concentrations of the working and stock standards that were used in the analysis. The reagents section outlines the IUPAC names of the standards, which were all purchased from Sigma-Aldrich Australia. There are normally two internal standards, one for the higher volatile components and the other for the lower volatile components. However since butanetriol was not available, tricaprin was used as the only internal standard to correct for internal disturbances in the analysis.

3.2.2 Procedure for stock standards This was weighed out the appropriate amount of standard required in a volumetric flask e.g. 50mg of monoglyceride in a 10ml volumetric flask for a concentration of 5mg/ml, then make up the flask with n Heptane to the 10ml mark. Glycerol, monoglyceride and diglyceride are dissolved in pyridine.

3.2.3 Procedure for working standards Pipette into a 10ml volumetric flask the appropriate volume of each stock solution of glycerol, monoglyceride and diglyceride (dissolved in pyridine), add 100 µL of MSTFA, cap and vortex. Leave to react for 20 min. Add the appropriate volume of ethyl palmitate, tricaprin (IS) and triglyceride stock solutions (dissolved in N-Heptane) to the 10ml volumetric flask and then dilute to the mark with N-Heptane, cap and mix.

3.2.4 Procedure for samples Weigh out 50-70mg of sample into a 10ml volumetric flask and mass recorded. Add 100 µL of MSTFA, cap, vortex and leave to react for 20 min. Add 250 µL of Tricaprin IS and dilute to the mark with n Heptane, cap and mix.

3.2.5 Procedure GC application For every batch of samples that were run on the GC, four standards would also be run. Each mixture of varying concentration of standards, S1, S2, and S3 would be used as a calibration curve to calculate the concentrations of each homogenous group. S2 would be run again last in the batch to check for any inconsistencies over the duration of the analysis.


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3.2.6 Typical Analysis Calculation A calibration curve would be in area under each peak vs. concentration for each homogenous group, as can be seen in figure 11.

Calibration Curve Monoglycerides (Example)

y = 682.38xR2 = 0.9996

0.0E+00

2.0E+04

4.0E+04

6.0E+04

8.0E+04

1.0E+05

1.2E+05

1.4E+05

1.6E+05

0 50 100 150 200 250

Concentration µg/ml

Are

a co

unts

Figure 11. Example of standards calibration curve

From the calibration curve with an original know mass of sample we can calculate the quantity of that compound and its relative proportions in the sample. As is as follows; Let’s say for example sake the area under the curve obtained from the GC, for the monoglycerides, sums to 4100.8 x counts and the original mass of sample was 58mg.

Cmxy += xx 38.682100.8 4 =

mlgx /2.117 µ= We know we had 10ml to start with so the mass of monoglycerides is

gx µ0.1172= With an initial mass of sample we can calculate the percentage of monoglycerides in the sample. Percentage of monoglycerides in the sample Table 12. Stock standards Component mg/ml Volumetric Flask (ml) Mass of sample (mg) Glycerol 25 25 625 Ethyl Palmitate 25 25 625 Monoglycerides 5 10 50 Diglycerides 5 10 50 Triglycerides 2 10 20 Tricaprin 2 10 20

%2021.010058000

0.1172==

gg

µµ


20

Table 13. Working standards Component µg/ml & ml S1 S2 S3 Glycerol 50 150 250 Stock 0.02 0.06 0.1 Ethyl Palmitate 500 1500 2500 Stock 0.2 0.6 1 Monoglycerides 50 100 200 Stock 0.1 0.2 0.4 Diglycerides 50 100 200 Stock 0.1 0.2 0.4 Triglycerides 50 100 150 Stock 0.25 0.5 0.75 MSTFA 10 10 10 Stock 0.1 0.1 0.1 Tricaprin 100 100 100 Stock 0.5 0.5 0.5

3.2.7 Equipment The analysis was conducted with Gas Chromatography (GC), with a DB-5 column, 15m in length with 0.32mm internal diameter and 0.1µm stationary phase. This is a capillary type column, made from silicone and is coated with 5% phenyl polydimethylsiloxane (PDS) as the stationary phase. The system is fitted with a pre-column that acts as a filter for some unwanted compounds. A suitable temperature-programming regime was established, to achieve a satisfactory compromise between resolution and the analysis time. Any compounds that will react with the stationary phase need to be neutralised. This is the case for the samples provided as some of the compounds in the sample may contain hydroxyl groups, which will bond to the column permanently. These problems can be overcome by firstly silylation of all the hydroxyl groups or derivatisation (Trimethylisation) of free and bound glycerol agents such as N, O-bis(trimethylsilyl)trifluoroacetamide (BASTFA) ( Plank C and Lorbeer, E) and secondly a short column with a larger diameter than the one currently being used will allow all of the compounds to be eluted. Another problem was the triglycerides not because of interaction with the stationary phase but the nature of the molecule itself. The size and structure of the molecule caused it to remain in the column even after a period of several hours. The problem with molecules such as this and the glycerol is that they will contaminate the first couple of meters of column and in the case of the triglycerides will make their way to the end of the column and exit when least expected and cause ghosting. This is where a compound exits the column unexpectedly and can conceal peaks that are being measured. Gas Chromatography GC-17A Ver 3 user’s manual SHIMADZU CORPORATION Analytical Instruments Division KYOTO, JAPAN GC Workstation Class-GC10 Operation Manual V1.3 SHIMADZU CORPORATION Analytical Instruments Division KYOTO, JAPAN


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3.2.8 Reagents The reagents that where used are listed below.

1. 1-mono [cis-9-octadeconyl]-rac-glycerol (monoolein) 2. 1, 3-di-[cis-9-octadecenoyl] glycerol (diolein) 3. 1, 2, 3-tri-[cis-9-octadecenoyl] glycerol (triolein) 4. 1, 2, 2-tridecanoylglycerol (tricaprin) 5. N-Methyl-N-trimethylsilyltrifluoroacetamide (MSTFA) 6. n-heptane (analytical grade) 7. Pyridine (analytical grade) 8. 2 (S)-(-)-1, 2, 4-butanetriol (Not available)

3.2.9 Conditions Many trials where run in order to find the best possible conditions for analysis which where found to be as follows. Initial oven temperature is 50°C for 2min, the oven was then heated at 15°C/min to 180°C, at 7°C/min to 230°C and 20°C/min to 375°C held for 8min. Helium was used as a carrier gas and hydrogen as the combustion source. The flame ionisation detector (FID) temperature was 370°C, with the injection port at 350°C and a run time of 30min.

3.2.10 Safety Safety issues are always paramount whilst handling chemicals and operating equipment such as pressure vessels. Although some chemicals in their natural form, such as glycerol are fairly innate, upon reaction or thermal change they can become toxic. It was found that glycerol, will thermally decompose at temperatures exceeding 290°C to acrolein, which is highly toxic. Care must be taken that this doesn’t occur and subsequently the temperature was kept below 290°C. Throughout the project proper handling of all chemicals was conducted and there were no incidents during this time. An initial assessment was conducted on the equipment, to ensure that all safety measures where in place. No safety breaches were conducted or any injuries incurred over the duration of this project. All MSDS for the chemicals used for this project can be found at http://chemwatch.chemistry.uq.edu.au/


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4.0 RESULTS 4.1 REACTIONS

. Figure 12. Low conversion with no catalyst, Valfor and Calcium carbonate respectively

Conversion for BioDiesel

05

101520253035404550556065707580859095

100

0 5 10 15 20 25 30 35 40 45 50 55 60 65

Time min

% C

onve

rsio

n

GlycerolEthyl EstersMono-Di-Tri-

Figure 13. Conversions vs. time for biodiesel run Bio0034

Bio0034 Temperature ~100°C Pressure 70bar

Run Time 60min Catalyst 42SOH Lipid Prime Tallow


23

Figure 14. High conversion for Saveall tallow and rapeseed oil

A complete table of the runs that are outlined in table 14 can be found in Appendices C & D. Table 14. Quantitative analysis of reactions

Batch # Conversion %

0001-0002 not analysed but conversion low due to reaction rate 0003 Total saponification (solid) soap 0004-006 Analysed but not quantitated conversion presumed to be 70-80% 0007 Total saponification (solid) soap 0008-0011 not analysed but conversion very low large qty of solid material 0012 Analysed but not quantitated conversion presumed to be 70-80% 0013-0017 not analysed but conversion very low large qty of solid material 0018-0021 Analysed but not quantitated conversion presumed to be 70-80% 0022-0027 not analysed but conversion very low large qty of solid material 0028 not analysed but total liquid in 10min 0029-0033 not analysed but conversion very low large qty of solid material 0034 Conversion greater than 95% 0035 not analysed but conversion very low large qty of solid material 0036 Conversion greater than 95%

4.2 ANALYSIS Figure 15 is a chromatogram of biodiesel sample (Bio0034) at time equal to 5 min and figure 16 is the same batch at 60min. As can be clearly seen the first peaks are glycerol followed by ethyl esters and mono-, di- and triglycerides. In figure 16 there are some monoglycerides remaining but generally the conversion is high, with large peaks for ethyl esters and glycerol.


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Figure 15. Chromatogram for Bio0034 at 5min

Figure 16. Chromatogram for Bio0034 at 60min


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5.0 DISCUSSION 5.1 ANALYSIS The development of an analysis technique required a considerable amount of time to establish. However, with this technique now proven to be reliable and effective, further research will not be hampered by this restriction. The complexity of the reactant mixture was one of the challenges in finding an appropriate method. Although, a combination of methods may have also been possible, it was not cost or time effective to have several methods of analysis, all requiring different preparation. GC analysis has proven to be the most appropriate method for this project, however for online qualitative analysis NIR may have some potential in being a quick qualitative method of assessing the extent of conversion. However, NIR will determine the major constituents of the reaction mixture but if the product is to meet international standards, further testing will have to be conducted, such as flash point, cloud point and various other tests.

5.2 ANALYSIS ERROR At this stage rigorous quantitative analysis has not been carried out as there are many components to consider if this is to be done correctly. In saying this, analysis was requested on some biodiesel samples that where supplied to a company for engine testing. Results of the analysis are tabulated in Appendices A & B. The samples were replicated on two different dates to demonstrate it was reproducible. An internal standard was included with each analysis to ensure and demonstrate consistency. The concentrations of internal standard in all of the measurements were found to be between 97.6 and 98.1 %, against the amount loaded into the samples, therefore known absolutely. The concentrations of the analysed constituents have consequently been normalised by a factor of 1.0215. Using this basis, the materials analysed accounted for effectively 90-95% of the samples, indicating at the outside ~8% of unknown constituents. However, when an absolute calibration was performed with the internal standard (tricaprin) it was shown that it registered as an increased value of 11%. Since there are calibration curves for each homogenous group, this discrepancy should be accounted for. Based on the replications and the fact that the method accounted for close to 90-95% of the sample mass, in each case, it was estimated that the analysis was accurate to about ~8%.

5.3 REACTIONS The reactions are relatively straightforward, as the equipment is simple and the reactants are very stable. The sampling method that was previously used was unacceptable and a new method was adapted to minimise the amount of sample taken and cover issues of contamination. There are some issues with getting the reaction to a desired temperature before the reaction reaches equilibrium. This is due to the time taken for the reactor to heat up, this can in some cases, and take up to 20min. Thus by the time the required temperature has been reached the reaction may have already reached equilibrium. A solution to this may be dynamic modelling which will generate some complex calculations but should give reasonable kinetic information.


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5.3.1 Catalysts Homogenous acid catalysts are very taxing on equipment and at elevated temperatures severely affect any metallic components. Although, acid catalysed reactions are slower than basic ones, they have potential if they can be immobilised. Problems with saponification are not present when esterification occurs and acid catalysts are not affected by FFA’s. Heterogenous catalysts are the key to new developments in the production of biodiesel, combined with their application in a continuous process and easy separation, they will substantially decrease the costs of production. Problems with water have not yet been fully addressed. There are some concerns over hydrolysis inhibiting the conversion in transesterification, this is yet to be tested and will need to be resolved in the near future.

6.0 CONCLUSIONS The main issues with this project where finding an analysis method, a suitable catalyst and obtaining useful kinetic data . Gas chromatography provides an appropriate method of chemical analysis and it can be suitably calibrated for the products of this reaction. The preparation methods for the samples have been established and the method’s reliability, precision and reproducibility have been demonstrated. The solid catalysts that were trialled do not appear to be effective. The results reported in the literature cannot be replicated and their veracity is doubtful. The homogenous acid catalysed reactions proved to be effective, but the nature of the catalyst may limit any future use. The batch reactor provides a convenient and safe method for screening catalysts and obtaining kinetic data. It is easily scaled up to a continuous reactor and a sampling method allowing samples to be taken within short intervals of two minutes has been implemented. The greater project is in good shape for rigorous catalyst testing and the equipment and methods have proven that a high level of accuracy can be obtained.

7.0 FUTURE WORK AND RESEARCH Preliminary catalyst trials are required to identify heterogenous candidates. This is the most important requirement for the work at this stage. Catalysts such as organic titanium oxides may hold some potential as they are currently used in the plastics industry for transesterification reactions. Once a range of catalysts have been identified, rigorous experimentation needs to be conducted with varying conditions. Kinetic data needs to be obtained for each catalyst in at least duplicate, preferably triplicate, to identify any discrepancies. The use of crude feed stocks is important if the cost of production is to be kept at a minimum, so catalysts would be tested with tallow and or used oils. Catalyst free reactions with supercritical methanol could potentially be a solution to many processing problems. There should be no reason why this reaction, carried out at pressures of up to 300atm, can not be conducted with supercritical ethanol. Further research into the conditions and equipment would be beneficial considering conversions are reported to be high, in the order of 98% in 3min. The information obtained from batch testing will be fundamental in the development of a continuous process. Once conditions and reaction system have been identified at the batch level, it will be necessary to run reactions in the continuous reactor at various conditions to optimise the process.


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Alternative separation techniques have not yet been adequately developed. Washing and settling are well established for commercial batch processes, but may not be practical for continuous processes. Product separation needs to be extensively researched for alternatives methods of product separation for continuous production. There will be a large volume of excess ethanol that needs to be separated and this could add significant costs to production if all options are not explored. Research into the method of near infrared spectroscopy and the equipment required needs to be further investigated as this may be a low cost online method to analyse the extent of conversion. Although the current method of analysis (gas chromatography) has proven to be the most effective method to analyse the full spectrum of the product mixture, it is not the most cost effective. There may be new technology still in its infancy that could offer a more cost effective and instantaneous analysis method.


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8.0 REFERENCES

1. Provisional specification for biodiesel fuel (B100) blend stock for distillate fuels. 2. Alcantara, R. et al. Catalytic production of biodiesel from soy-bean oil, used frying oil

and tallow. Biomass and Bioenergy 18, 515-527 (2000). 3. Ali, Y., Hanna, M. A. & Borg, J. E. Optimization of diesel, methyl tallowate and ethanol

blend for reducing emissions from diesel engine. Bioresource Technology 52, 237-243 (1995).

4. Allen, C. A. W., Watts, K. C., Ackman, R. G. & Pegg, M. J. Predicting the viscosity of biodiesel fuels from their fatty acid ester composition. Fuel 78, 1319-1326 (1998).

5. Boocock, D. G. B., Konar, S. K., Mao, V. & Sidi, H. Fast one-phase oil-rich processes for the preparation of vegetable oil methyl esters. Biomass and Bioenergy 11, 43-50 (1995).

6. Boocock, D. G. B., Konar, S. K., Mao, V., Lee, C. & Buligan, S. Fast formation of high-purity methyl esters from vegetable oils. Journal of American Oil Chemical Society 75 (1998).

7. Boocock, D. G. B. (2001). 8. Boocock, D. G. B., Konar, S. K., Blakansky, G. V. & Zhou, W. in 51st Canadian

Chemical Engineering Conference (2001). 9. Canakci, M. & Gerpen, V. J. Biodiesel production via acid catalysis. American Society

of Agricultural Engineers 42, 1203-1210. 10. Corma, A., Miquel, S., Iborra, S. & Velty, A. 11. Cvengrosova, Z., Cvengros, J. & Hronec, M. Rapeseed oil ethyl esters as alternative fuels

and their quality control. Petroleum and coal 39, 36-40 (1997). 12. Foglia, T. A., Jones, K. C., Haas, M. J. & Scott, K. M. Technologies supporting the

adoption of biodiesel as an alternative fuel. The cotton gin and oil mill press (2000). 13. Freedman, B., Pryde, E. H. & Mounts, T. L. Variables affecting the yields of fatty esters

from transesterified vegetable oils. Journal of american Oil Chemical Society (1984). 14. Freedman, B., Kwolek, W. F. & Pryde, E. H. Quantitation in the analysis of

transesterified soybean oil by capillary gas chromatography. Journal of American Oil Chemical Society 63 (1986).

15. Graboski, M. S. & McCormick, R. L. Combustion of fat and vegetable oil derived fuels in diesel engines. Prog. Energy Combustion Sci. 24, 125-164 (1998).

16. Holcapek, M., Jandera, P., Fischer, J. & Prokes, B. Analytical monitoring of the production of biodiesel by high performance liquid chromatography with various detection methods. Journal of chromatography A, 858, 13-31 (1999).

17. Knothe, G. Rapid monitoring of transesterification and assessing biodiesel fuel quality by near-infrared spectroscopy using a fiber-optic probe. Journal of American Oil Chemical Society 76, 795-800 (1999).

18. Knothe. Monitoring a progressing transesterification reaction by fiber-optic color near infrared spectorscopy with correlation to 1h nuclear magnetic resonance spectroscopy. Journal of american Oil Chemical Society 77 (2000).

19. Korbitz, W. in World fuel ethanol congress (Beijing, China, 2001). 20. Kusdiana, D. & Saka, S. Kinetics of transesterification in rapeseed oil to biodiesel fuel as

treated in supercritical methanol. Fuel 80, 693-698 (2000). 21. Ma, F., Clements, L. D. & Hanna, M. A. The effects of catalyst, free fatty acids, and

water on transesterification of beef tallow. American Society of Agricultural Engineers 41, 1261-1264 (1998).

22. Ma, F. & Hanna, M. A. Biodiesel production: a review. Bioresource Technology 70, 1-15 (1999).

23. Ma, F., Clements, L. D. & Hanna, M. A. The effect of mixing on transesterification of beef tallow. Bioresource Technology 69, 289-293 (1999).

24. Mittelbach, M. Diesel fuel derived from vegetable oils, V[1]: gas chromatographic determination of free glycerol in transesterified vegetable oils. Chromatographia 37 (1993).

25. Mittelbach, M. Diesel fuel derived from vegetable oils, VI: specifications and quality control of biodiesel. Bioresource Technology 56, 7-11 (1996).

26. Mittelbach, M., Roth, G. & Bergmann, A. Simultaneous gas chromatographic determination of methanol and free glycerol in biodiesel. Chromatographia 42 (1996).


29

27. Muniyappa, P. R., Brammer, S. C. & Noureddini, H. Improved conversion of plant oils and animal fats into biodiesel and co-product. Bioresource Technology 56, 19-24 (1996).

28. Peterson, C. L., Reece, D. L., Thompson, J. C., Beck, S. M. & Chase, C. Ethyl ester of rapeseed used as a biodiesel fuel - a case study. Biomass and Bioenergy 10, 331-336 (1995).

29. Peterson, C. L. et al. 1-8 (University of Idaho, College of Agriculture, Idaho, 1996). 30. Plank, C. & Lorbeer, E. Simultaneous determination of glycerol, and mono-, di- and

triglycerides in vegetable oil methyl esters by capillary gas chromatography. Journal of chromatography A, 697, 461-468 (1995).

31. Resources, D. E. (2001). 32. Shimada, Y., Watanabe, Y., Sugihara, A. & Tominaga, Y. 33. Sonntag, N. O. V. Oleochemicals as renewable molecules; Prospects for the 21st century.

Journal of american Oil Chemical Society 59, 795A (1982). 34. Suppes, G. J. et al. Calcium carbonate catalyzed alcoholysis of fats and oils., (2001). 35. Trathnigg, B. & Mittelbach, M. Analysis of triglyceride methanolysis mixtures using

isocratic hplc with density detection. Journal of liquid chromatography 13, 95-105 (1990).

36. Van Gerpen, J. H. et al. 1-28 (Iowa State University, Iowa, 1996). 37. Ali, Y. & Hanna, M. A. (1994a). Physical properties of tallow ester and diesel fuel

blends. Bioresourses Technology, 47, 131-4 38. Bondioli P, Gasparoli A, Lanzani A, Fedeli E, Veronese S, Sala M. Storagability of

biodiesel. Journal of American Chemicals Society 1995: 72:699-702. 39. Freedman B, Pryde EH, Mounts TL. Variables affecting the yields of fatty esters from

transesterified vegetable oils. Journal of American Oil Chemicals Society. 1984; 61:;1638-43.

40. Kemp W. In: Practical organic chemistry. London: McGraw-Hill, 1967. p 99. 41. Allen CAW, Watts KC. A batch type transesterification unit for biodiesel fuels,

Technical paper 96-404, Canadian society of Agricultural Engineers, 1996. 42. Allen CAW, Watts KC, ACKMAN rg. Properties of methyl esters of interesterified

triacylglycerols Proceeding of the Third Liquid Fuel Conference. Liquid fuels and industrial products from renewqable resources. St. Joseph, MI: ASAE, 1996 pp. 73-82.

43. Boocock DGB, Konar SK, Mao V, Lee C, Buligan S. JAOCS 1998;75:1167. 44. Deslandes N, Bellenger V, Jaffiol F, Verdu J. Applied Polymer Science 1998; 69:2663 45. Freedman, B., Butterfield, R.O., Pryde, E.H., 1986. Transesterification kinetics of

soybean oil. JAOCS 63, 1375-1380. 46. Freedman, B., Pryde, E.H., Mounts, T.L., 1984. Variables affecting the yields of fatty

esters from transesterified vegetable oils. JAOCS 61, 1638-1643. 47. Sonntag, N. O. V. (1982). Glycerolysis of fats and methyl esters – status, review, and

critique. JAOCS, 59 (10), 795A-802A. 48. Peterson, G. L. (1986). Vegetable oil as a diesel fuel: staus and research priorities. Trans.

ASAE, 29 (5), 1413-22. 49. Hanna, M. A., Ali, Y., Cuppett, S. L., Zhang, D., 1996. Crystallization characterisics of

methyl tallowate and its blend with ethanol and diesel fuel. JAOCS 73, 759-763. 50. Ma, F., Clements, L.D., Hanna, M.A., 1998. Biodiesel fuel from animal fat. Ancillary

stusies on transesterification of beef tallow. Ind. Eng. Chem. Res. 37, 3768-3771. 51. X. Zhang, C. L. Peterson, D. Reece, G. Moller and R. Haws, Biodegradability of

biodiesel in the aquatic environment. ASAE Paper No. 956742. ASAE, St. Joseph, MI 49085-9659 (1995).

52. Reference: list from Biodiesel production: a review. Fangrui Ma, Milford A. Hanna. 53. Smelser, N.J. (1987). ‘Fats and Fatty Oils’. In Ullmann’s Encyclopaedia of Industrial

Chemistry. Fifth ed: Weinhein. Vol. A10, pp. 173-243.


30

APPENDIX A - Data for requested sample analysis

Run One Conducted on 09/04/2002 Sample# PJ-02-06 Glycerol Ethyl Pal Mono- Di- Tri- Area 0 2149807 2733 19497 Conc 0 3217.792247 0 6.259734 71.791 Mass 0 32177.92247 0 62.59734 717.91 Orig_Mass 57400 57400 57400 57400 57400 0 0.560590984 0 0.001091 0.012507 % 0 56.05909837 0 0.109055 1.250714 57.41887 2.15% 0 57.26436899 0 0.111399 1.277605 58.65337 Sample# PJ-02-07 Glycerol Ethyl Pal Mono- Di- Tri- Area 0 0 0 0 Conc 0 0 0 0 0 Mass 0 0 0 0 0 Orig_Mass 57400 57400 57400 57400 57400

0 0 0 0 0

% 0 0 0 0 0 0 2.15% 0 0 0 0 0 0 Sample# PJ-02-08 Glycerol Ethyl Pal Mono- Di- Tri- Area 0 3460155 11360 0 22637 Conc 0 5179.097441 39.12789 0 136.1624 Mass 0 51790.97441 391.2789 0 1361.624 Orig_Mass 57600 57600 57600 57600 57600 0 0.899148861 0.006793 0 0.023639 % 0 89.91488612 0.679304 0 2.363931 92.95812 2.15% 0 91.84805617 0.693909 0 2.414755 94.95672 Sample# Mixed Glycerol Ethyl Pal Mono- Di- Tri- Area 0 3255611 0 12624 6160 Conc 0 4671.963435 0 28.91434 22.68208 Mass 0 46719.63435 0 289.1434 226.8208 Orig_Mass 55800 55800 55800 55800 55800 0 0.837269433 0 0.005182 0.004065 % 0 83.72694328 0 0.518178 0.406489 84.65161 2.15% 0 85.52707256 0 0.529319 0.415228 86.47162


31

APPENDIX B - Data for requested sample analysis # 2

Run Two Conducted on 11/04/2002 Sample# PJ-02-06 Glycerol Ethyl Pal Mono- Di- Tri- Area 2546 4352846 7935 479 Conc 2.680366787 6973.032808 0 5.646883 1.763753 Mass 26.80366787 69730.32808 0 56.46883 17.63753 Orig_Mass 77600 77600 77600 77600 77600 0.000345408 0.898586702 0 0.000728 0.000227 % 0.034540809 89.8586702 0 0.072769 0.022729 89.98871 2.15% 0.035283437 91.79063161 0 0.074334 0.023217 91.92347 Sample# PJ-02-07 Glycerol Ethyl Pal Mono- Di- Tri- Area 0 4116736 27469 15656 Conc 0 6594.796873 0 19.54811 57.64784 Mass 0 65947.96873 0 195.4811 576.4784 Orig_Mass 74400 74400 74400 74400 74400

0 0.886397429 0 0.002627 0.007748

% 0 88.63974292 0 0.262743 0.774837 89.67732 2.15% 0 90.54549739 0 0.268392 0.791496 91.60539 Sample# PJ-02-08 Glycerol Ethyl Pal Mono- Di- Tri- Area 0 3545770 8057 0 9193 Conc 0 5680.139049 11.8072 0 33.85006 Mass 0 56801.39049 118.072 0 338.5006 Orig_Mass 60100 60100 60100 60100 60100 0 0.94511465 0.001965 0 0.005632 % 0 94.51146504 0.196459 0 0.563229 95.27115 2.15% 0 96.54346154 0.200683 0 0.575338 97.31948 Sample# Mixed Glycerol Ethyl Pal Mono- Di- Tri- Area 0 4508526 5613 0 41397 Conc 0 7222.424068 8.225622 0 152.4302 Mass 0 72224.24068 82.25622 0 1524.302 Orig_Mass 80000 80000 80000 80000 80000 0 0.902803008 0.001028 0 0.019054 % 0 90.28030085 0.10282 0 1.905378 92.2885 2.15% 0 92.22132731 0.105031 0 1.946343 94.2727 Sample# Tricaprin Tricaprin Area 3028139 Conc 4658.532045 Mass 46585.32045 Orig_Mass 41800 1.114481351 % 111.4481351


32

APPENDIX C – Tabulated data on experiments Reactants gTallowPrime SaveAll Oil EtOH Valfor KOH Temp Press bar Time min glycerol mono- di- tri- EtOH Esters

0001 250 72 2.5 30 1 1200002 250 77.53 2.64 30 1 1200003 250 77.53 29.94 30 1 1200004 150 1.5 230 50 600005 150 61.3 1.5 230 50 1200006 150 61.3 1.5 230 50 1200007 150 46.51 28.8 230 50 600008 250 77.53 37.5 70 1 1800009 250 77.53 37.5 55 1 1800010 150 46.5 22.5 210 50 1800011 150 46.05 1.5 70 1 1800012 250 77.53 2.5 70 1 4800013 150 46.5 1.5 230 50 1800014 150 46.5 1.5 230 50 1800015 150 69.8 1.5 230 50 1800016 150 46.5 1.5 230 50 600017 150 46.05 1.5 230 50 600018 250 77.5 4 70 1 1800019 250 77.5 2.5 70 1 1800020 150 46.5 2.5 230 50 600021 250 77.5 2.5 70 1 9600022 100 95.26 6.4 210 50 1800023 100 95.3 6.4 210 50 3000024 100 100.3 6.4 Marb 210 50 1800025 100 95.3 6.4 210 50 1200026 50 100 15 240 60 180

Conversion %

not analysed but coversion low due to reaction ratenot analysed but coversion low due to reaction rate

Batch # Catalyst Reaction Conditions

Total saponification (solid) soap

Not analysed but coversion presumed to be 70-80%

Total saponification (solid) soapnot analysed but coversion very low large qty of solid materialnot analysed but coversion very low large qty of solid materialnot analysed but coversion very low large qty of solid materialnot analysed but coversion very low large qty of solid material

not analysed but coversion seems 70-80%not analysed but coversion very low large qty of solid materialnot analysed but coversion very low large qty of solid materialnot analysed but coversion very low large qty of solid materialnot analysed but coversion very low large qty of solid materialnot analysed but coversion very low large qty of solid material

not analysed but coversion seems 70-80%not analysed but coversion seems 70-80%not analysed but coversion seems 70-80%

not analysed but coversion very low large qty of solid materialnot analysed but coversion very low large qty of solid material

Conversion high but quantitative analyis not conductednot analysed but coversion very low large qty of solid materialnot analysed but coversion very low large qty of solid materialnot analysed but coversion very low large qty of solid material

42 SOH 3CaCO


33

APPENDIX D - Tabulated data on experiments

Prime SaveAll Oil EtOH Valfor KOH CaO Temp Press bar Time min glycerol mono- di- tri- EtOH Esters0028 50 150 (75%) 5 240 70 1800029 100 95.3 6.41 240 70 1800030 100 95.3 240 70 1800031 26.9 DEG 34.99 2 210 60 1800032 26.9 DEG 34.99 2 210 1 1800033 26.9 DEG 34.99 2 210 1 1800034 100 51 2.652 240 70 600035 26.9 DEG 34.99 2 210 1 1800036 150 81.9 3.98 240 70 4500370038003900400041004200430044004500460047004800490050005100520053

Conversion %

not analysed but total liquid in 10min not analysed but coversion very low large qty of solid material

no catalyst not analysed but coversion very low large qty of solid material

Conversion greater than 90% in first 15min

not analysed but coversion very low large qty of solid materialnot analysed but coversion very low large qty of solid materialnot analysed but coversion very low large qty of solid material

Conversion greater than 90% not analysed but coversion very low large qty of solid material

Batch # Reactants g Catalyst g Reaction ConditionsTallow

42 SOH 3CaCO


34

APPENDIX E – Pressure Vs. Temperature for Water & Ethanol

Pressure Vs Temperature Water & EtOH

0

5

10

15

20

25

30

35

40

45

50

55

60

90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240

Temperature C

Pres

sure

bar Water

Ethanol

[ Temp °C ] [ Pressure bar ]EtOH 242.8 63.9Water 240.0 33.4


35

APPENDIX F – Calibration curve for triglycerides

Calibration Curve Triglycerides

y = 166.25xR2 = 0.9027

0.00E+00

5.00E+03

1.00E+04

1.50E+04

2.00E+04

2.50E+04

3.00E+04

0 20 40 60 80 100 120 140 160

Concentration

Are

a


36

APPENDIX G - Calibration curve for diglycerides

Calibration Curve Diglycerides

y = 724.38xR2 = 0.9605

0.00E+00

2.00E+04

4.00E+04

6.00E+04

8.00E+04

1.00E+05

1.20E+05

1.40E+05

1.60E+05

0 50 100 150 200 250

Concentration

Are

a

a


37

APPENDIX H - Calibration curve for monoglycerides

Calibration Curve Monoglycerides

y = 290.33xR2 = 0.9082

0.00E+00

1.00E+04

2.00E+04

3.00E+04

4.00E+04

5.00E+04

6.00E+04

7.00E+04

0 50 100 150 200 250

Concentration

Are

a


38

APPENDIX I - Calibration curve for glycerol

Calibration Curve Glycerol

y = 1227xR2 = 0.9972

0.00E+00

5.00E+04

1.00E+05

1.50E+05

2.00E+05

2.50E+05

3.00E+05

3.50E+05

0 50 100 150 200 250 300

Concentration

Are

a


39

APPENDIX J - Calibration curve for ethyl esters

Calibration Curve Ethyl Esters

y = 668.1xR2 = 0.9983

0.00E+00

2.00E+05

4.00E+05

6.00E+05

8.00E+05

1.00E+06

1.20E+06

1.40E+06

1.60E+06

1.80E+06

0 500 1000 1500 2000 2500 3000

Concentration

Are

a

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