Developmet of bio based aviation fuels the production process, properties, soot characteristics and gas turbine engine tests

DEVELOPMENT OF BIO-BASED AVIATION FUELS: THE PRODUCTION PROCESS, PROPERTIES, SOOT CHARACTERISTICS AND GAS TURBINE ENGINE TESTS DISSERTATION Submitted in partial fulfillment of the requi

DEVELOPMENT OF BIO-BASED AVIATION FUELS: THE PRODUCTION PROCESS, PROPERTIES, SOOT CHARACTERISTICS AND GAS TURBINE ENGINE TESTS

DISSERTATION

Submitted in partial fulfillment of the requirements of doctoral degree at

Institut Teknologi Bandung

By HONG DUC THONG NIM: 33110002

Study Program of Mechanical Engineering Faculty of Mechanical and Aerospace Engineering

INSTITUT TEKNOLOGI BANDUNG

2014

DEVELOPMENT OF BIO-BASED AVIATION FUELS: THE PRODUCTION PROCESS, PROPERTIES, SOOT CHARACTERISTICS AND GAS TURBINE ENGINE TESTS

Co-Supervisor: Co-Supervisor:

_ (Dr Ir Iman K Reksowardojo) (Prof Dr Osamu Fujita)

ABSTRAK PENGEMBANGAN BAHAN BAKAR AVIASI BERBASIS NABATI (BIO): PROSES PRODUKSI, KARAKTERISTIK BAHAN BAKAR, JELAGA DAN PENGUJIAAN PADA

MOTOR TURBIN GAS

Sebagai langkah awal prosedur untuk menerapkan bahan bakar dalam penggunaan bidang penerbangan, adalah melakukan penelitian karakteristik jelaga, prestasi, dan emisi dari BK5 pada motor turbin gas, yang merupakan

campuran dari 5% vol Bio-P1 dan 95% vol commercial Jet A-1, untuk dibandingkan dengan referensi Jet A-1 Pendekatan yang berguna untuk memahami kencenderungan jelaga dari aviation bio paraffin Bio P-1 adalah dengan membandingkan dengan bahan bakar jet surrogate Oleh karena itu, pertama yang dilakukan adalah percobaan untuk campuran bio-paraffins/propylbenzene (Bio-P1/PB) aviasi dan campuran dodecane/propylbenzene (Do/PB), yang merupakan campuran dari masing-masing

0, 10, 20, 25% vol propylbenzene dalam aviation bio-paraffins dan dodecane Metode light extinction diadopsi untuk menentukan volume total dari jelaga (TSVs), yang terdapat pada co-annular smoke-free laminar diffusion wick-fed flames, sebagai fungsi dari tinggi nyala api dan tingkat konsumsi bahan bakar (FMCR) Selanjutnya, model empiris dibuat untuk memprediksi TSVs dari campuran Do/PB dan campuran Bio-P/PB sebagai fungsi dari dua variabel dari FMCR dan konsentrasi dari propylbenzene Kemudian, karateristik dari jelaga BK5 dan Jet A-1 diobservasi sebagai perbandingan Terakhir, prestasi, emisi dari BK5 dan Jet A-1 komersial di dalam Rover 1S/60 gas turbine engine dilaporkan

di dalam penelitian

Disertasi ini telah memperoleh beberapa temuan dan kontribusi penting sebagai berikut: dapat dicampurkan secara langsung dengan 5% volume dari Bio-P1 dan 10% volume dari Bio-JP2 dengan Jet A-1 komersial untuk membentuk bio-kerosene sebagai bahan bakar alternatif untuk pesawat terbang tanpa merancang ulang sistem bahan bakar atau infrastruktur pasokan bahan bakar Kegunaan dari bio-paraffin tidak hanya mengurangi siklus CO2, tapi juga mengurangi emisi dari Sulfur oksida (SOx) secara signifikan Aviation Bio-P1 itu sangat mirip dengan dodecane dalam hal karakteristik pembentukan jelaga Dengan kata lain, dodecane dapat menjadi pengganti (surrogate) aviation Bio-P1 Pada FMCRs yang rendah, BK5 dapat menghasilkan TSVs sedikit lebih tinggi dari Jet A-1 Akan tetapi pada saat FMCRs yang tinggi, TSVs dari jet A-1 akan sedikit lebih tinggi dibandingka BK5 Pada penelitian motor turbin gas tidak ada perbedaan yang signifikan antara konsumsi bahan bakar spesifik di Jet A-1 dan BK5 Pembakaran dari BK5 akan mengurangi temperatur masuk turbin, temperatur gas buang, dan emisi HC bila dibandingkan dengan Jet A-1 Pada

beban yang rendah, BK5 akan menghasilkan emisi NOx dan emisi CO yang lebih rendah bila dibandingkan dengan Jet A-1 Akan tetapi pada beban tinggi kecenderungannya menjadi terbalik, konsentrasi NOx dan CO dari Jet A-1 lebih rendah

Dari hasil penelitian ini, tidak diragukan lagi kelayakan untuk mengembangkan proses produksi dari bahan bakar alternatif ini dalam bidang penerbangan di Indonesia dan juga negara-negara tropis lainnya BK5 menghasilkan kinerja yang serupa dan emisi gas buang dan pembentukan jelaga yang kompetitif bila dibandingkan dengan Jet A-1 komersial Hal ini memprediksi bahwa BK5 akan memiliki emisi gas buang dan karakteristik jelaga yang lebih baik dari Jet A-1 pada saat digunakan pada pesawat dengan teknologi turbin gas modern Oleh sebab itu bio-parafin aviasi yang diteliti dapat menggantikan sebagian dari bahan bakar jet berbasis fosil, meskipun campuran dari bio-kerosene harus memenuhi persyaratan dari ASTM untuk menjadi bahan bakar aviasi ketika digunakan di pesawat terbang Hasil ini juga mengindikasikan bahwa diperlukan perbaikan dalam proses produksi dengan menghilangkan komponen dengan temperatur distilasi yang tinggi dari aviation bio-fuel saat ini

Kata kunci: Hydroprocessing, bahan bakar nabati, paraffins,

bio-kerosene , kerosin, aviasi, bahan bakar jet, surrogate, jelaga, api difusi, motor turbin gas, performa, emisi gas dan pembakaran

ABSTRACT DEVELOPMENT OF BIO-BASED AVIATION FUELS: THE PRODUCTION PROCESS, PROPERTIES, SOOT CHARACTERISTICS AND GAS TURBINE ENGINE TESTS

of bio-kerosenes: distillations, freezing point, lower heating value, density, flash point and viscosity to ensure ASTM criteria of jet fuel

As a required step of the procedure for applying the fuel to aviation use, soot characteristics, performances and emissions of BK5, which is the blend of 5% vol Bio-P1 and 95% vol commercial Jet A-1, have been investigated to

compare with the reference of Jet A-1 A useful approach in understanding soot propensity of the aviation bio-paraffins of Bio-P1 is to compare with that of jet fuel surrogate Thus, the experiments are firstly performed for aviation bio-paraffins/propylbenzene (Bio-P1/PB) mixtures and dodecane/propylbenzene (Do/PB) mixtures, which are the blends of 0, 10, 20, 25% vol propylbenzene in aviation bio-paraffins and dodecane, respectively A light extinction method is adopted to determine the total soot volumes (TSVs), which exist in co-annular smoke-free laminar diffusion wick-fed flames, as a function of flame height and fuel mass consumption rate (FMCR) Furthermore, the empirical models are built

to predict TSVs of Do/PB mixtures and Bio-P/PB mixtures as the function of two variables of FMCR and concentration of propylbenzene Then, soot characteristics

of BK5 and Jet A-1 are observed for comparison Finally, performances, emissions of BK5 and commercial Jet A-1 in a Rover 1S/60 gas turbine engine are reported in the research

The dissertation has gained some important findings and contributions as follows: It can be blended directly 5% volume of Bio-P1 or 10% volume of Bio-JP2 to commercial Jet A-1 to form bio-kerosene as an alternative fuel for aircraft without redesigning fuel system or fuel supply infrastructure The use of these bio-paraffins not only reduces CO2 lifecycle but also significantly decreases emissions of sulfur compounds (SOx) Aviation Bio-P1 is very similar to dodecane in terms of soot formation characteristics In other words, dodecane can

be a proper surrogate to the aviation Bio-P1 At low FMCRs, BK5 produces slightly higher TSVs than Jet A-1 In contrast, at high FMCRs, TSVs of Jet A-1 are slightly higher than those of its counterparts There is no obvious difference in brake specific fuel consumption between Jet A-1 and BK5 Combustion of BK5 reduces turbine inlet temperature, exhaust gas temperature and HC emissions in comparison with Jet A-1 In the low loads, BK5 produces less NOx and CO emissions than its counterpart The trends, however, are expressed reversely at the high load range, the lower NOx and CO concentrations are obtained for Jet A-1

In summary, with the achievements of this research we can conclude that it

is no doubt about the feasibility for developing a production process of aviation

alternative fuels for Indonesia as well as the tropical countries BK5 produces similar performance and competitive gaseous emissions and soot formation against commercial Jet A-1 It is predicted that BK5 has better exhaust gas emissions and soot characteristics than Jet A-1 when burning in modern aircraft engine It obviously can replace a part of fossil-based jet fuel by aviation bio-paraffins, however, the blend of bio-kerosene must to satisfy requirements of ASTM for aviation fuel when using for aircrafts The results also indicate that it should be improved the production process by liquidating the high distillation temperature components of current aviation biofuel

Keywords: Hydroprocessing, biofuel, bio-paraffins, bio-kerosene, kerosene,

aviation, jet fuel, surrogate, soot formation, diffusion flame, gas turbine engine, performance, gaseous emissions and combustion

For my beloved

GUIDE TO DISSERTATION USE

The unpublished dissertation is listed and available at the Institut Teknologi Bandung Library, and is opened to public in which the copyright is retained by the author adhering to the regulation of intellectual property rights at Institut Teknologi Bandung It is allowed to write down the references The citation and

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following the common practice to properly cite the source

The publication and reproduction of dissertation (whole or in part) should be made with the permission of the Dean of Graduate School, Institut Teknologi Bandung

ACKNOWLEDGMENT

First of all, I would like to express my sincere and profound gratitude to all my supervisors: Assc Prof Abdurrachim Halim, Assc Prof Tatang H Soerawidjaja, Assc Prof Iman K Reksowardojo and Prof Osamu Fujita, for their advices and supports throughout this research project time

I am pleased to acknowledge the financial support of the Japanese International Cooperation Agency (JICA) under the project of ASEAN University Network/Southeast Asia Engineering Education Development Network (AUN/SEED-Net) for the Scholarship of Doctoral Degree Sandwich Program

I wish to thank the Japanese International Cooperation Agency (JICA), JICA Hokkaido Center, JICA Project Office for AUN/SEED-Net, JICA Indonesia Office, JICA Vietnam Office, Combustion Engines and Propulsion Systems Laboratory, Faculty of Mechanical and Aerospace Engineering, Laboratory of Catalysis and Chemical Reaction Engineering, Department of Chemical Engineering Î Institut Teknologi Bandung (ITB), Department of Automobile and

Engines Faculty of Transport Engineering Î Ho Chi Minh City University of

Technology (HCMUT), Division of Mechanical and Space Engineering Î

Hokkaido University, ITB International Relation Office, HCMUT External Relations Office as well as their all past and present staffs for kind helps in arrangement of the travel, in processing of documents and in offering me good condition to pursue my research Thanks also to Research & Development Division of Pertamina Oil Company and Ms Zarrah Duniani for supplying the biofuels for the experiments of this research

I would like to thank to Dr Toto Hardianto, Dr Tirto P Brodjonegoro, Prof Dr Prawoto and Ibu Puji N Handayani for their critical feedbacks to sharpen the final manuscript

I would like to thank to my lecturers, colleagues and friends ITB, Hokkaido University and HCMUT, especially, Prof Wiranto Arismunandar, Ms Risca

am very proud to dedicate them this piece of research

I 1 Introduction to the Research Topic 1

I 2 Dissertation Scope, Objectives and Methodologies 5

I 3 Dissertation Outline 6

II.1 State of the Art of Aviation Biofuels 8 II.1.1 The General Studies and Reviews of Aviation Alternative

II.2.6 Fuel Emission Factor and Recognition of Biofuels 24 II.2.7 Summary of European Study on Sustainable Way for

Alternative Fuels and Energy in Aviation (SWAFEA) 25 II.3 Concluding Remarks 28

PRODUCTION PROCESS Î EXPERIMENTAL AND THEORETICAL EVALUATION OF THEIR BLENDS

III.1 Current Status of Production Process for Aviation Biofuels 29 III.1.1 Fatty Acid Esters (FAEs) 29 III.1.2 Hydroprocessed Renewable Jet Î Synthesis Paraffin

Kerosene (HRJ Î SPK) 31 III.1.3 Fischer-Tropsch Jet Î Synthesis Paraffin Kerosene

III.5.5 The Analysis of Flash Point 45

III.5.6 Examination of viscosity 45 III.5.7 The Analysis of the Environmental Impact 47

Chapter IV: INVESTIGATIONS OF SOOT FORMATION FOR JET

FUEL SURROGATES, AVIATION BIO-PARAFFINS, KEROSENE AND BIO-KEROSENE IN LAMINAR

IV.1 Soot Particle Measurement by Method of Light Extinction 51

IV.2.1 Experimental Setup and Description 53

Do/PB Mixtures and Bio-P/PB Mixtures 60

IV.3.3 Soot Characteristics of Do/PB Mixtures and Bio-P/PB

IV.3.4 Comparison of Soot Characteristics Between Do/PB

Mixtures and Bio-P/PB Mixtures 69 IV.4 Soot Characteristics of Kerosene and Bio-Kerosene 73 IV.4.1 Flame Images of Jet A-1 and BK5 73 IV.4.2 The Relationships Between FMCR and Flame Height of

Kerosene and Bio-Kerosene 73 IV.4.3 Comparison of Soot Characteristics Between Kerosene

Chapter V: PERFORMANCES AND GASEOUS EMISSIONS OF

V.2.1 Experimental Setup and Description 80

V.3.1 Effect of Brake Power on Brake Specific Fuel Consumption

V.3.2 Effect of Brake Power on Turbine Inlet Temperature (TIT),

Exhaust Gas Temperature (EGT) and NOx Emissions 86 V.3.3 Effect of Brake Power on CO Emissions 88 V.3.4 Effect of Brake Power on HC Emissions 89

Appendix D: DPX Frounde Hydraulic Dynamometer 121 Appendix E: The Apparatuses for Doing the Experiments 123

aviation biofuel proposed for Indonesia 34 Figure III.5 Molecular transformation steps for creating undecane

(nÎC11H24) and dodecane (nÎC12H26) 36 Figure III.6 Freezing point versus volume fraction of Bio-P1 in

Figure III.10 Linear relationship of density and volume fraction of

Bio-P1 and Bio-JP2 in blends 43 Figure III.11 Experimental density versus volume fraction of Bio-P1

Figure III.12 Relationship of Z Î temperature of Jet A-1, BK1-5 and

Figure IV.1 The schematic diagram of experimental setup 53 Figure IV.2 The equipment and apparatuses for experiment 55 Figure IV.3 Images of flames at the height of 28mm, (a) Î (h)

correspond with fuel samples (1) Î (8), respectively 58 Figure IV.4 Shadow images of back light, (a): fuel (4) at flame

height of 14 mm, (b): fuel (4) at flame height of 28 mm and (c): fuel (2) at flame height of 28 mm 59 Figure IV.5 FMCR versus flame height of 8 samples of fuel 60 Figure IV.6 TSV versus flame height of (a): Do/PB mixtures and

(b): Bio-P/PB mixtures 62 Figure IV.7 TSV versus FMCR of (a): Do/PB mixtures and (b):

Figure IV.8 Comparison of TSV versus flame height of Do/PB

mixtures and Bio-P/PB mixtures 71 Figure IV.9 Comparison TSV versus FMCR of Do/PB mixtures and

Figure IV.12 Comparison of TSV versus (a): flame height and (b):

FMCR between kerosene and bio-kerosene 74 Figure V.1 Schematic diagram of experiment setup 80 Figure V.2 The equipment and apparatuses for experiment 81 Figure V.3 BSFC as a function of brake power for Jet A-1 and BK5 85 Figure V.4 TIT, EGT and NOx emissions as the functions of brake

power for Jet A-1 and BK5 87 Figure V.5 CO emissions as a function of brake power for Jet A-1

Figure V.6 HC emissions as a function of brake power for Jet A-1

LIST OF TABLES

Table III.1 Fatty acid compositions of some potential feedstocks 35 Table III.2 The common properties of Bio-P1, Bio-JP2 and Jet A-1 37 Table III.3 The distillations of Bio-P1, BK1-2, BK1-5 and BK1-10 38 Table III.4 Kinematic viscosities of Jet A-1, BK1-5, BK2-10, Bio-

P1 and Bio-JP2 at various temperatures 47 Table IV.1 The samples of experimental fuel 56 Table IV.2 Typical properties of dodecane and propylbenzene 57 Table IV.3 Common properties of Jet A-1, BK5 and bio-paraffins 57 Table IV.4 The experimental correlation of FMCR, flame height and

TSV of 8 different fuel samples 64 Table IV.5 The functions of TSV of Do/PB mixtures and Bio-P/PB

mixtures for the relationships between (Œ岌f) and (%PB) as independent variables 67 Table IV.6 The functions of TSV of Do/PB mixtures and Bio-P/PB

mixtures for the relationships between (Œ岌f) and (%PB) as dependent variables 68 Table V.1 Brief specifications of SPTC gas & smoke analyzer 82 Table V.2 Brief specifications of Rover 1S/60 gas turbine engine 83 Table V.3 Common properties of Jet A-1, BK5 and bio-paraffins 84

log Logarithm to base 10

Z Function of Kinematic viscosity mm2/s

I Transmitted light intensity W

I0 Incident light intensity W

L Absorption path length m

N Number density of particle m-3

Ac Cross section area of particle m2

Cext Extinction cross section m2

Qext Extinction efficiency m-1

z"?"ヾf1 Particle size diameter

Incident light wavelength nm

m = n - ki Soot complex refractive index

n Real part of m

xx

k Imaginary part of m

Re Real value of a complex number

Im Imaginary value of a complex number

fv Soot volume fraction

VS Total soot volume (TSV) 10-3 mm3

fvi Soot volume faction at point i

vi Volume of flame at point i mm3

Vf Total volume of flame mm3

Œ岌f Fuel mass consumption rate mg/s

D0 diffusion coefficient at 300K

T0 Initial fuel and air temperature K

Tf Mean flame temperature K

S Volume of air required to burn a volume of fuel

R Total coefficient of determination

D Mean difference observation

n The number of observations

xxi

Fi Sum of the difference observations

&辿態 Sum of the squared difference observations

SD Standard deviation of the difference observations

n Number of observed points

µD

Mean difference observation of null hypothesis

population

tobtained Obtained t value

tcritical Critical t value

P Probability level

AIT Air inlet temperature

TIT Turbine inlet temperature

EGT Exhaust gas temperature

Subscript

( )i Component of ith

( )mix Mixture

1

Chapter I:

INTRODUCTION

I 1 Introduction to the Research Topic

The depletion of fossil-based liquid fuel resources and the phenomenon of climate change are two significant problems which the world civilization is currently confronting Utilization of renewable fuels such as biodiesel, bioethanol, etc has been known as one of the most viable solution for these both problems In fact, research and development on the commercial productions and applications of biofuels have dramatically advanced and these fuels have been used more and more in automotive and stationary engines as well as for heating purposes However, the use of biofuels in air transport is still limited since (a) the fuel consumptions of aviation industry are significantly less than those of ground transportation; and (b) the requirements of aviation fuel are much more stringent than the other fuels

Recently, however, aviation alternative fuels considerably attracted the interest of and have been seriously prepared by many researchers, the airline operators and energy entrepreneurs 2008 due to the following reasons:

i The European Union Emissions Trading Scheme (EU ETS)

The European Commission approved the EU ETS to include the civil aviation sector Directive 2008/101/EC of the European Parliament and Council [1] agreed that from 2012, all airlines flying within or into Europe have had to buy CO2 allowances on the open market or reduced their GHG emissions to 97% of average annual emissions for the year 2004 Î 2006 and

this will be reduced further to 95% as from 2013 Under the EU ETS, biofuels are considered CO2 neutral [2, 3] and airline can benefit from an exemption from the need to surrender allowances and credits

2

ii. The Price Fluctuation of the Fossil-Based Fuel

Fuel is one of the biggest operating costs for the air transport, hence the aviation industry is significantly affected by the oil prices Meanwhile the crude oil and petroleum products price permanently fluctuate according

to the socio-political situation of the ockp" qkn" tgugtxguÓ" countries and the yqtnfÓu economy In 10 years, the difference of jet fuel prices between the

peak set in June 2008 (3.89 USD/gallon) and the lowest in May 2003 (0.71 USD/gallon) was more than 5.4 times [4] The changing fuel prices make airline operators very difficult to plan and budget for the long-term operating expenses Thus, they have tried to develop a diversified fuel market to reduce risk in the fuel volatility that comes with having a single source of energy

iii. The Substantial Growth of the Air Transport Industry

Vqfc{Óu"cktnkpg"kpfwuvt{"ku"92'"oqtg"hwgn"ghhkekgpv"vjcp"qxgt"vjg"rcuv"

40 years [5] because of more aerodynamic and lighter aircrafts, more efficient-modern turbine engines, huge improvements in the air traffic control efficiency, in flying the aircraft and in developing more environmentally-friendly operations at airports Aviation CO2 emission, however, is still kept growth of 2 Î 3% per year due to the steady increase in

annual air transportation

iv The Ambitious Target of the International Air Transport Association (IATA)

for Aviation CO2 Emissions

IATA [3] adopted ambitious and immediate goals for industry-wide emissions reductions that will lead to carbon-neutral growth by 2020 and achieve a 50% reduction in net carbon emissions by 2050 compared with

2005 Biofuels have been an essential part of the plan because they are a drop-in replacement for jet fuel with nearly identical properties, but net CO2emissions are reduced by up to 80%

3

Some candidates of bio-jet fuels have therefore been developed and tested, accomplished for certification and successfully tested in flights, especially in Europe and the USA The aviation biofuel production plants have being planned and constructed Although the progress that has been achieved is impressive, there are still challenges to achieve large-scale production and adoption of sustainable aviation biofuels

After initially testing some types of alternative aviation fuels made from bioresources, air transport industries, aircraft manufacturers and aviation fuel companies mutually agreed that to satisfy the stringent safety requirements of air transportation, aviation biofuels should be consist of the same classes of molecules as those of conventional fossil-based aviation fuels The groups of hydrocarbons in jet fuels can be classified into paraffin (normal and iso), cycloparaffin (or naphthene), aromatic The best representative components of jet fuel surrogates are respectively n-dodecane, iso-dodecane and propylbenzene [6] The popular feedstock for making bio-jet fuels in Europe and USA are presently fatty oils obtained from jatropha curcas, camelina sativa, canola, soybean, various microalgae, etc These are glyceride oils which are composed of fatty acids in the range of C16 Î C20 (mostly contain stearic C18:0, oleic C18:1, linoleic C18:2, and linolenic C18:3 acids) Therefore, the production processes to make jet biofuels from these raw materials must involve a cracking step to shorten the chain lengths of the paraffins so that they fall within the average range of C12

(dodecane) In generally, the current production processes of aviation biofuels are similar to refining process of crude oils, so it is hard to implement this process in developing countries or lower

Application of renewable fuels, in form blending with conventional jet fuels, will be an inevitable trend of the future airline industry It will bring a great significance kp" okvkicvkpi" cxkcvkqpÓu" vqvcn" fgrgpfgpeg" qp" rgvtqngwo-based fuel,

stimulating the national agricultural development, stabilizing the domestic socioeconomics and energy security and leading to a cleaner industry image for the nation However, each country or each region has different natural conditions,

4

resources and potentials, therefore, the identification of proper production process and appropriate technology for aviation biofuels are really important and necessary

There are many advantageous features to develop aviation biofuels in Indonesia [7 Î 9] such as (a) this country has a lot of plants and plenty of available

lands that yield potential feedstocks for biofuels; (b) there is a good policy for supporting development of biofuels form government; (c) renewable fuels have been studied strongly, manufactured and used for ground transportation in this country; (d) in particular, this nation is the main producer of lauric oils, which are considered as the most suitable feedstock for making bio-jet fuels since the number of carbons of its molecular chain length are same with jet fuel The production process of aviation biofuel from lauric oil can remove the cracking step and thus it becomes much more simple and consistent with the reality of Indonesia From there, this dissertation topic was generated

In this research, the production process of aviation bio-jet paraffins was proposed in accordance with the socio-economic conditions, production technology and feedstock resources of Indonesia The first two prototypes of bio-paraffins were manufactured as the result in cooperation of Research & Development Division of Pertamina Oil Company and Institut Teknologi Bandung, Indonesia The route of blending bio-paraffins with fossil-based kerosene (commercial Jet A-1), which forms bio-kerosenes as an alternative fuel for aircraft, have been displayed The experimental and theoretical investigations

of these bio-kerosenes have been performed to ensure their common properties satisfying the ASTM D1655 requirements As a required step of procedure for applying the new fuel to aviation use, the soot formation characteristics of diffusion flames, gas turbine performances and emissions of bio-kerosene of BK5 (5% vol bio-paraffins and 95% vol commercial Jet A-1) have been experimentally studied using those of commercial Jet A-1 as a comparative reference

5

I 2 Dissertation Objectives, Methodologies and Scope

ATAG [5] emphasized that biofuel testing is imperative to determine suitability for aviation because safety is the aviation industry's top priority Those potential biofuels have to undergo an exhaustive rigorous process of testing in laboratories, in equipment on the ground and under the extreme operating conditions that the aviation industry requires The dissertation, which is an original study in field of aviation alternative fuels, has resolved the first two out of three issues of the rigorous testing processes for fuel used in aircrafts It aims to verify the feasibility of the research and development of aviation biofuel for Indonesia and tropical countries

The research is also expected to produces a fundamental premise as the first significant contribution towards further studies for flight tests, applications for certification of new aviation fuels It has an important role to take the initiative in researching, developing and commercializing aviation biofuel industry in Indonesia as well as tropical regions The objectives and methodologies of dissertation can be detailed in the following main works:

(1) To propose the production process of the aviation biofuel for Indonesia and

the pathway to make bio-kerosene To verify the critical properties of the bio-kerosenes matching the ASTM requirements In this work, distillations, freezing point, lower heating value, viscosity, density, flash point of the mixtures of commercial Jet A-1 and bio-paraffins have been theoretically and experimentally investigated The environmental impact of aviation biofuel has been also analyzed The bio-paraffins, which were used to make bio-kerosenes, were manufactured by Research and Development Division

of Pertamina Oil Company according to the proposed production process

bio-paraffins/propylbenzene mixtures and dodecane/propylbenzene mixtures in order to understand soot propensity of the aviation bio-paraffins To compare soot formation characteristics between Jet A-1 and bio-kerosene of BK5 so that we can determine effect of bio-paraffins on soot formation

6

when adding them to petroleum-based Jet A-1 This work has been carried out in co-annular smoke-free laminar diffusion wick-fed flames with using light extinction method to determine the soot formation

(3) To compare the performances and gaseous emissions of Jet A-1 and

bio-kerosene of BK5 from Rover 1S/60 gas turbine engine in order to understand of effects of bio-paraffins on combustion of gas turbine engine (4) To understand the basic knowledge of aviation biofuel and the related issues

of the research, background and literature review have been drawn and cited most heavily in books, literatures, technical reports, papers, journals and websites etc

The scope of dissertation is limited in comparison of soot characteristics, performances and gaseous emissions between Jet A-1 and BK5 The research did not carry out for pure bio-paraffins or blends of bio-kerosene which contained greater than 5% volume fraction of bio-paraffins because: (a) there was not enough bio-paraffins production for experiments; (b) the specifications of bio-kerosenes would not meet ASTM standard if the volume fraction of bio-paraffins exceeded 5% in blend; moreover, (c) in the short and medium terms, Indonesia has not had an ambition yet to use aviation alternative fuels with larger than 5% volume

I 3 Dissertation Outline

There are six chapters in this dissertation starting with the present one entitled ÐQxgtxkgy"qh"vjg"FkuugtvcvkqpÑ

Chapter II, ÐNkvgtcvwtg" Tgxkgy" cpf" DcemitqwpfÑ, introduces the previous

studies and the relevant knowledge that relate to the research field of dissertation The production process of the aviation biofuel, the pathway to make bio-kerosene, the theoretical and experimental investigations for the critical properties

of bio-kerosenes are discussed in Chapter III, which is named ÐFgxgnqrkpi" vjg"

Surrogates, Aviation Bio-Paraffins, Kerosene and Bio-Kerosene in Laminar

Fkhhwukqp"HncoguÑ

Chapter V, ÐRgthqtocpegu" cpf" Gaseous Emissions of Kerosene and

Bio-Kerosene from Gas Turbine Engine TestÑ, analyzes the effects of bio-paraffins on

performances and emissions of gas turbine engine when 5% vol kerosene is replaced by bio-paraffins

Finally, Chapter VI entitled ÐEqpenwukqpu"cpf"Recommendations for Future YqtmuÑ"ogpvkqpu"vjg"tguwnvu"cpf"hkpfkpiu" obtained from this research and some

recommendations for further studies and expand research directions

8

Chapter II:

LITERATURE REVIEW

II.1 State of the Art of Aviation Biofuels

Until now, there is still very limited the studies of aviation biofuels which have been published and the publications have mainly come from the cooperation

of several certain research organizations, energy companies and airline industries etc In generally, the research topics have been focused mostly on development and applicability of aviation alternative fuels derived from plant oils and biomass sources The first order topic is typical representative by hydroprocessed renewable jet Î synthesis paraffinic kerosene (HRJ Î SPK) fuels and fatty acid

esters (FAEs) Fischer-Tropsch jet Î synthesis paraffinic kerosene (FTJ Î SPK)

fuels are typically represented for the later order topic Besides, there are some studies on utilization of biofuels (biodiesels, vegetable oils etc.) for the gas turbine engines which use as ground applications In there, combustions, performances and emissions of engines have been primarily examined without considering the rigorous requirements of aircraft fuels The brief reviews are introduced in following sections

II.1.1 The General Studies and Reviews of Aviation Alternative Fuels

Daggett et al [10] considered the potential to replace or supplement petroleum-based jet fuels from methanol, ethanol, liquid natural gas, liquid hydrogen and synthetic fuels The results showed that (a) most of these fuels present safety, logistical and performance challenges in airplane design; (b) synthetic fuel made from coal, natural gas or other hydrocarbon feedstock shows significant promise as a fuel for present and future aircraft with little or no modification to current aircraft designs

9

The other study of Daggett et al [11] about alternate fuels for commercial aircraft presented that FTJ fuels (from coal, natural gas or other hydrocarbon feedstocks) are very similar in performance to conventional jet fuel but have almost zero sulfur and aromatics These synthetic fuels produce lower particulate exhaust emissions and less fuel system deposits The major challenges of using pure biofuels in a commercial aircraft are its propensity to freeze at normal operating cruising temperatures, its poorer high temperature thermal stability characteristics in the engine, and its storage stability over time The short-term option of synthetic fuels processed in the FTJ process has the potential to release pressure from pure crude oil derived fuels without a long delay However, it will not reduce CO2 emissions over the entire life cycle Moreover, if the additional process related CO2 emissions are not captured and sequestered, the total CO2

emissions may double The mid-term options, including future renewable derived bio-fuels and its blends with synthetic fuels, offer the promise of a complete replacement for crude oil derived fuels

Bomani et al [12] investigated past, present and possible future biofuels, specifically, the use of ethanol, cellulosic ethanol, biodiesel and synthetic fuel blends that can potentially be used as fuels for aviation and non-aerospace applications The investigations included the processing of biomass via gasification, hydrolysis and anaerobic digestion as a way to extract fuel oil from alternative biofuels sources The results showed that (a) synthetic oil and hydrogen present promise for the future as we look for efficient, safe and affordable biofuels as a replacement for fossil fuels; (b) biodiesel from algae and halophytes also show great promise because of their ability to serve as fuel sources and inedible food sources

Hileman and coworkers [13], from Massachusetts Institute of Technology (MIT), carried out the study on potential alternative jet fuels, environmental life-cycle and alternative jet fuel comparison matrix The results showed that (a) coal-to-liquid fuels via FT process with carbon dioxide capture and sequestration (CCS) have comparable lifecycle CO2 to conventional fuel and their use could improve air quality, without CCS, lifecycle CO2 will double (or triple with low

10

efficiency and poor quality coal); (b) alternative fuels such as HRJ and to-liquids via FTJ process could both reduce lifecycle CO2 and improve air quality but at present the ability to produce these fuels is limited

biomass-The other study of Hileman and coworkers [14] presented in their forthcoming study which investigated ten potential alternative jet fuels showed that (a) within the next decade, the production potential of alternative jet fuels without policy incentives is on the order of ten percent of expected consumption; (b) the emissions of particulate matter and precursors are significantly lower for many of the fuels considered in the study; (c) the life-cycle carbon dioxide emissions of the alternatives range from roughly zero to many multiples of conventional fuel depending on the feedstock, the conversion technology, any indirect land use changes, the availability of opportunities for geologic CCS; (4) ultra-low sulfur jet fuel can provide an immediate means for reducing emissions that degrade air quality while also paving the way for future alternative jet fuels The third study of MIT, from Hileman and coworkers [15], considered the energy content of biofuel and alternative jet fuel viability The study investigated the chemical composition and energy content of several fuel options as energy per unit mass and energy per unit volume Based on the results, the fleet-wide use of pure SPK fuels, such as those created from FTJ or HRJ process, could reduce aircraft energy consumption by 0.3% In contrast, biodiesel and alcohols will result in increased fuel volume usage and also a decrease in fleet-wide energy efficiency

Blakey et al [16] provided a relatively complete overview of aviation gas turbine alternative fuels The study reported the commercially available process technologies (transesterfication, FTJ and HRJ processes) to produce alternative fuels and the lifecycle assessments A summary of the recent alternative fuel flight tests and engine demonstrations, a review of combustion performance for the alternative fuels including ignition characteristics, particle emissions, NOx, CO,

HC, CO2 emissions were given Experimental data, from an auxiliary power unit engine, were provided The prospects for future fuel development were also

11

discussed The notable conclusions of this overview presented that (a) FAMEs are unsuitable for aviation use due to the carryover of metal contaminants from the raw feedstock; (b) Bio-SPKs are proving to be a sustainable alternative to conventional jet fuel; (c) alternative fuels have significant environmental benefits due to reduced CO2 emissions and reduced particulate emissions

II.1.2 The Studies on Development and Applicability of HRJ Fuels

UOP LLC, a Honeywell Company, and Boeing Company are the pioneers in this field and have published some reports and publications of development and applicability of aviation biofuel The studies of UOP LLC have focused to develop the production technologies for aviation plant oil-derived fuels [17 Î 20] d{" wukpi" hngzkdng" hggfuvqemu"cpf" wpfgtiq" vjg" j{ftqrtqeguukpi" vq" rtqfweg" Ðftqr"kpÑ"lgv"hwgnu0"The production of aviation biofuel from renewable feedstocks was

registered patent application publication [21] in 2009 with inventors of McCall et

al from UOP Î Honeywell Company Besides, UOP also has had research

collaboration with airlines which is typical of Boeing Company [22 Î 24] The

studies mainly are demonstration of technical feasibility (such as hwgnÓu"

specifications testing, demonstrating ground engine tests and flight tests, application for fuel certification) and sustainable development of biofuel (such as demonstrating CO2 lifecycle, identifying sustainable feedstock sources, cost and promoting development of viable commercial markets)

The most notable studies of a cross-industry team consisting of Boeing,

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General Electric, CFM International, Pratt & Whitney and Rolls-Royce are the research reports of evaluation of bio-derived synthetic paraffinic kerosenes [25, 26], which has been actively encouraging the development of a jet fuel that will support the goals of the aviation industry to reduce life cycle CO2 emissions, meet

or exceed current fuel specification properties and be cost-competitive The studies presented the progress in the use of sustainable, naturally derived oils to produce 50% Bio-SPK blends that were tested in commercial aircraft, systems and engines The feedstock selection and processing methods used to produce a SPK

12

were reported The fuel property testing and performance, operability, emissions

of engine and flight test results were also discussed

An overview [27] of the catalysts used for hydro-deoxygenation of various vegetable oils, the nature of the catalysts, reaction conditions necessary and selectivity of the catalysts were presented by authors come from Malaysia and India The result showed that in general supported noble metal catalysts, sulfide metal catalysts and reduced metal catalysts are used to be active for deoxygenation of the oil feedstock However, reduced metal catalysts give the most convenient because the noble metal catalysts are not cost-effective and sulfide catalysts result in sulfur-contaminated products

II.1.3 The Studies on Development and Applicability of FAEs (Biodiesel)

Dunn [28] examined the feasibility of blending methyl soyate esters (SME)

in 10 Î 30% vol blends with JP-8 Testing of cold flow properties indicated that

blends with as little as 10% vol SME may limit operation of aircraft at ambient temperature of lower than Î30o

C Treatment of SME with cold flow improver additives may decrease this limit by up to 9oC Blending with winterized SME gave the best results, reducing the limit to as low as Î47o

C

Cromarty and Abanteriba [29] performed an experimental and theoretical investigation to identify and evaluate the key technical issues surrounding the 'drop-in' utilization of alternative biofuels in aviation gas-turbine propulsion system The bio-fuel selected for further evaluation was a locally produced mustard seed oil derivative bio-fuel which was blended at various blend ratios with standard Jet A-l turbine fuel

In the studies of Llamas and coworkers [30, 31], coconut, palm kernel, babassu and camelina oils have been transesterified with methanol by the classical homogeneous basic catalysis method with good yields The FAMEs have been subjected to fractional distillation at vacuum and the low boiling point fractions have been blended with two types of fossil kerosene, a straight-run atmospheric distillation cut and a commercial Jet A1 The blends were investigated for some

13

selected specifications of the ASTM D1655 standard: smoke point, density, flash point, viscosity at Î20o

C and freezing point and low calorific value

Jenkins et al [32] attempted to address some key issues, which limit the applicability of these biofuels as substitutes in the road transport sector, a range of possible renewable fuels were synthesized from esterified fermentation products potentially derivable from cellulosic sugars These mono- and di-esters were then examined for their potential as a replacement for aviation kerosene, mineral diesel

or petrol To determine the most suitable replacements, where appropriate, the fuelsÓ" density, kinematic viscosity, melting point, boiling point, flash point,

miscibility, solubility in water, the oxidative stability, lubricity and cetane number were examined and compared to their fossil fuel counterparts

Baroutian et al [33] were produced aviation biofuels by blending of the methyl esters of waste vegetable and jatropha curcas oils with aviation Jet A-1 Several blends of aviation biofuels were characterized to determine the most suitable ratio based on the jet fuel specifications

II.1.4 The Studies on Development and Applicability of FTJ Fuels

Moses [34] reported a development of the protocol for acceptance of synthetic fuels, using FTJ processing, under commercial specification The fuel may either contain aromatics from the FTJ process or no aromatics These two fuel possibilities may be used either as a blending stream for a semi-synthetic jet fuel or as a fully synthetic jet fuel The fuel must meet the specification requirements of a recognized aviation fuel specification such as ASTM D 1655

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other defined properties and characteristics that fall within the range of experience with petroleum-derived jet fuel

Corpran et al [35] performed the study on emissions characteristics of a turbine engine and research combustor burning conventional military jet fuel (JP-8), a natural-gas-derived FTJ fuel and blends of the two Nonvolatile PM and gaseous emissions were analyzed to assess the impacts of the aromatic and sulfur-

14

free synjet fuel on the combustion products of the two platforms The engine was operated at two power settings, and the combustor at several equivalence ratios, to evaluate the emission production over a wide range of combustion temperatures DeWitt et al [36] carried the study of effects of aromatic type and concentration in FTJ fuel on emissions production and material compatibility Study was performed to investigate the feasibility of adding aromatic solvents as

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improve seal-swell characteristics, but also increase engine soot emissions Three aromatic solvents, which encompass the molecular weight range typically found

in military jet fuel (JP-8), were added both individually and as a blend to an FTJ fuel at varying concentrations The seal-swell capability of the solvents was inferred using nitrile, fluorosilicone, and fluorocarbon O-rings while the solvent effect on combustion emissions was evaluated using a T63 engine

Moses [37] reported the comparison of the properties and characteristics of five blends of individual synthetic paraffinic kerosenes with petroleum-based Jet

A, Jet A-1 or JP-8 fuel to make semi-synthetic jet fuels The study to provide technical support for the acceptance of SPK derived from synthesis gas as blending streams up to 50% vol in fuel specifications for aviation turbine fuel Takeshita and Yamaji [38] examined the potential roles of FTJ synfuels in the 21st century with a global energy model treating the entire fuel supply chain in detail

Behrendt et al [39] showed two substitution strategies are currently under investigation Î the use of oil from plant seeds either directly or after chemical

modification (biodiesel) or the gasification of complete plants, use of the product gases (mainly CO and H2) in a FTJ process with subsequent refining The authors proposed a third possible pathway would be the so-called direct liquefaction, i.e., the conversion of complete plants into liquid fuels without gasification This process is discussed and various technical implementations are critically evaluated

in the present paper

15

Eyersdorf and Anderson [40] represented an overview of the NASA alternative aviation fuel experiment which is to investigate the effects of synthetic fuels on: (a) engine performance; (b) engine and auxiliary power unit gas and particle emissions and characteristics; and (c) volatile aerosol formation in aging exhaust plumes The NASA DC-8, which has CFM-56 engines, was used as the test platform and the test fuels included standard JP-8 along with two synthetic fuels produced from natural gas and coal feedstocks using the FTJ process

The other study of NASA was performed by Miake-Lye et al [41] who reported the effects of alternative fuels on hydrocarbon and particle emissions from aircraft engines The possible alternatives usually result in a change in the detailed hydrocarbon make-up of the fuels, which might be anticipated to result in changes in the emissions released when burning these fuels

Moses and Roets [42] presented the study of properties, characteristics, and combustion performance of Sasol fully synthetic jet fuel (FSJF) which was produced from coal using FTJ processes The research identifies the tests and presents the results demonstrating that Sasol fully synthetic jet fuel is fit-for-purpose as jet fuel for civilian aviation Sasol FSJF is the first fully synthetic jet fuel approved for unrestricted use

Lobo et al [43] reported the results of the first measurements of PM emissions from a CFM56-7B commercial jet engine burning conventional and alternative biomass- and FT-based fuels PM emissions reductions are observed with all fuels and blends when compared to the emissions from a reference conventional fuel, Jet A1 and are attributed to fuel properties associated with the fuels and blends studied

Timko and coworkers [44] reported the combustion emissions data for several alternatives to petroleum based Jet A jet fuel, including a natural gas-derived FF synthetic fuel; a 50/50 blend of the FT synthetic fuel with Jet A-1; a 20/80 blend of a fatty acid methyl ester (FAME) with jet fuel; and a 40/60 blend

of FAME with jet fuel The chief distinguishing features of the alternative fuels are reduced (for blends) or negligible (for pure fuels) aromatic content and

16

increased oxygen content (for FAME blends) A CFM International CFM56-7 gas turbine engine was the test engine, and they measured NOx, CO, speciated volatile organic compounds (including oxygenates, olefins, and aromatic compounds), and nonvolatile particle size distribution, number, and mass emissions They developed several new methods that account for fuel energy content and used the new methods to evaluate potential fuel effects on emissions performance

II.1.5 The Studies on Applicability of Biofuels for Stationary Gas Turbine

Engines

Nascimento et al [45] carries out the performance and emission tests on the 30kW micro-turbine engine fed with diesel, biodiesel and their blends as fuel A cycle simulation was also performed using the Gate Cycle GE Enter software in their study to evaluate the thermal performance of the 30kW micro-turbine engine

Bradshaw et al [46] have been identified the volatile trace species produced

by gasification in the integrated gasification combined-cycles gas turbines burning biomass and waste-fuels These trace elements may form molten surface deposits

on high temperature blades and vanes along the gas path and thereby initiate hot corrosion In the study, example fuel analyses (from the ECN PHYLLIS fuels database) have been used in a series of thermodynamic assessments using the MTDATA software package The assessments identified trace species containing cadmium, lead and antimony, in addition to alkali metals

Bolszo et al [47] investigated the operation of a 30 kW gas turbine engine operated on biodiesel Atomization, vaporization, combustion and emissions are compared for operation of the gas turbine on biodiesel and, as a reference, diesel fuel distillate #2 The role of liquid properties on fuel preparation and subsequent engine performance, injector operation on the resulting droplet sizes and fuel vaporization characteristics are examined

17

Habib et al [48] studied performance and emissions characteristics of a 30

kW gas turbine engine burning Jet A, soy methyl ester, canola methyl ester, recycled rapeseed methyl ester, hog-fat biofuel and their 50% vol blends in Jet A

Rehman et al [50] performed experiment on IS/60 Rovers gas turbine by using diesel and biodiesel (jatropha oil methyl ester) B15 and B25 The test rig is equipped with a dynamometer for turbine loading and AVL exhaust gas analyzer has been used to record emissions, hydraulic dynamometer, Heenan Froude make, was used to observe the turbine load variations

Allouis et al [51] carried out measurements of ultrafine particles at the exhaust of a low emission micro turbine for power generation This device has been fuelled with liquid fuels, including commercial diesel oil, a mixture of the diesel oil with a biodiesel and kerosene, and tested under different loads Primarily attention has been focused on the measurements of the size distribution functions of the particles emitted from the system by using particle differential mobility analysis

Rye et al [52] determined the degree in which different fuel compositions affected ignition performance Experimental ignition loops were obtained from representative combustion sections at atmospheric pressure Selected fuels included: a gas-to-liquid synthetic, Jet A-1, a thermally stressed Jet A-1 and diesel

18

Chiaramonti et al [53] measured emissions on a Garrett GTP 30Î67 liquid

fuel micro gas turbine, which was a combined heat and power production unit, at various loads An in-house test bench was designed, engineered, instrumented and built Diesel was characterized and then, different first generation biofuels, such

as vegetable oil and biodiesel were tested

Furthermore, there are some authors have interested this field like Strenziok

et al [54] were carried out the experimental work with a small commercial gas turbine type T216 of 75 kW-electric capacity The emissions were measured for both wood based bio-oil and diesel fuel operation French [55] run an SR-30 gas turbine engine with biodiesel fuel (made from unused oil and used oil) to broaden the educational experience of the engineering students in various classes Krishna [56] performed the tests of biodiesel blends as a fuel in a Capstone C30 micro-turbine with a nominal rating of 30 kW The blends, in ASTM #2 heating oil, ranged from 0% to 100% soy based biodiesel and no changes were made to the micro-turbine system for operation on the blends Klassen et al [57] compared emissions of biodiesel (soy methyl ester) and ethanol, natural gas, fuel oil #1, fuel oil #2 by using a commercial dry low emissions gas turbine nozzle designed for lean, premixed combustion of natural gas with no modifications to the nozzle hardware

II.2 Implications of Aviation Biofuels

II.2.1 The Benefits and Advantages of Developing Biofuels for Aviation

Industry (Source: [5])

a Biofuels could be approximately carbon neutral over their life cycle, see the Figure II.1 If we account the emissions produced from growing the crop, transporting the raw goods, refining the fuel and so on, they are still provided an up to 80% reduction in overall CO2 lifecycle emissions compared to fossil fuels

b Furthermore, biofuels contain roughly free aromatics, sulfur which cause lesser long term health effects on the human