This document summarizes a study on the combustion of blends of palm olein and distillate oil as an alternative fuel for industrial gas turbines. The study examined the physical and chemical properties of blended palm olein/diesel fuels. A combustion test rig was used to analyze combustion characteristics, emissions, temperature profiles and smoke for different blended fuel compositions. Results showed that blends with up to 40% palm olein performed similarly to diesel fuel alone in terms of emissions and combustion, but higher palm olein content led to increased NOx emissions and poorer combustion. The document recommends a maximum of 40% palm olein blending for use in gas turbines.
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Combustion Studies By Dr. Ahmed
1. COMBUSTION STUDIES OF PALM OLEIN/DISTILLATE
OIL BLENDS – AN ALTERNATIVE GREEN FUEL FOR
INDUSTRIAL GAS TURBINES
Prof. Dr. Farid Nasir Ani
Ahmad Hussain
Muhammad Irfan Shaikh
Faculty of Mechanical Engineering,
Universiti Teknologi Malaysia,
Skudai, Johor Bahru,
Malaysia
March 2008
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2. INTRODUCTION
Depletion of fossil energy resources earlier than expected and
environmental concerns has prompted the world to reconsider extensive
research on renewable energy resources in recent years.
Vegetable oils have been seen as a promising source of renewable
energy, due to the increasing prices of crude petroleum oil which is
controlled by OPEC.
Many countries in the world today have taken measures to substitute or
partly substitute fossil diesel with vegetable oil.
Malaysia has been considering converting palm oil as energy source
since mid 80’s but the commercialization of palm diesel has been
impeded by the price of palm oil that remains higher than fossil diesel.
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3. INTRODUCTION
Recently, palm olein from vegetable oil has gained attention as a new
renewable energy source to substitute fossil diesel.
This work examines the technical potential of biodiesel produced from
palm olein as gas turbine fuel in Malaysia.
TNB Research Sdn. Bhd. is currently conducting a research on
“Technical Studies of Palm Olein/Diesel Oil Blends as a Gas Turbine
Fuel”.
The studies which cover an investigation into the physical and chemical
properties of blended palm olein/diesel oils, other works relating to the
technical, environment and commercial impact, and the technique for
combustion test of this oil in test rig has been proposed
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4. Status of Blended Oil Use in Gas Turbines
Current gas turbine systems that are capable of
burning fuels are normally developed for a single
specific fuel (such as natural gas or domestic fuel oil)
and use conventional diffusion flame technology with
relatively high levels of NOx and partially unburned
species emissions. (Adoune et. al 2001)
Extensive research work is being done in atomization
and spray characteristics of liquid fuels, the
combustion and emission characteristics of the
selected alternative fuel flames, the sooting tendency
and NOx emission properties of the fuels under various
operation conditions. (Sharma et. al 2004)
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5. Status of Blended Oil Use in Gas Turbines
Fatty acid methyl esters (FAME) is being used as
alternative fuel, in gas turbines, as they have
similar properties to Diesel fuel, FAMEs are
alternative fuels capable of being directly used in
a turbine and can be blended in various
proportions with Diesel fuel (generally 5% or
30% FAME in Diesel fuel). (Iskender et. al 2004)
The high C/H ratio (high carbon content) of the
ash pyrolysis oil from wood, the vegetable oils
and the methyl esters may pose a problem of
deposits in the combustion chamber of gas
turbines. (Sierra et. al 2005) 5
6. Status of Blended Oil Use in Gas Turbines
Burning bio-oils in gas turbines is also
receiving an increased interest. There are
however only few studies on the later subject.
( Boucher et. al 2000)
The hot section components can be damaged
by high-temperature corrosion due to the ash
present in the biofuel, which reduces the
protective oxide surface film of the alloy.
( Aulisa et. al 2004)
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7. Physical Properties of Palm Olein
The physical characteristics of blended palm Olein/
diesel fuels are different from crude palm oil or
diesel fuel
Viscosity is a critical property of any liquid fuel
particularly for gas turbine combustion.
High viscosity of the fuel affects the fuel
atomisation behaviour of the burner and could
results in poor ignition characteristic, smokes and
lower combustion efficiency or increase the
formation of carbon.
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8. Physical Properties of Palm Olein
The methods of testing on the physical and chemical properties are
given in Table below:
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9. Physical Properties of Palm Olein
PROPERTIES OF DISTILLATE/PALM OLEIN BLENDED FUELS
D/PO 100/0 80/20 60/40 50/50 40/60 0/100
KINEMATICS 3.973 6.799 10.21 12.81 16.74 40.41
VISCOSITY
(cSt)ASTM D
445-94
GROSS 50,640 45,440 44,100 44,170 44,570 42,000
CALORIFIC VALUE
(kJ/kg)ASTM D
240-76
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12. Combustion Firing Test Rig
The combustion chamber is made of 310S stainless-steel cylindrical
tube of 290 mm internal diameter and 1690 mm length, with outside
ceramic fiber insulation.
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13. Fuel Oil Burner
The burner used in this system is RIELLO 40G Series G10 with
heat output range 54 to 120 kW.
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17. Temperature Measurement
The surface temperature profile of the flame was measured with K-
type thermocouples which can withstand the temperature up to
1300oC. These thermocouples are 8mm in diameters and coated
with stainless steel to alleviate effect of the combustion flame.
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18. Emission Measurement
Telegan Tempest 100 Combustion Performance
Gas analyzer probe mounted to exhaust section
Analyzer
The probe using to measure mean gasses from exhaust section.
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19. Fuel Blending
Blended fuels stored in containers
Blades of the stirrer
Blending were done for following:
80% Diesel 20% Palm Olein
70% Diesel 30% Palm Olein
60% Diesel 40% Palm Olein
50% Diesel 50% Palm Olein
40% Diesel 60% Palm Olein
Fuel Blending Apparatus
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20. SMOKE AND SOUND MEASUREMENTS
BOSCH Smoke Meter
Sound Level Meter
BOSCH Smoke Evaluating Unit
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29. RECOMMENDATIONS
As far the temperature distribution and flame
structure is concerned, it is recommended that the
palm olein blending should not be done in excess of
40%.
As NOx emission increases rapidly as the palm
olein concentration increases above 40% so the
blending should be kept around 30%.
The soot formation is important for the extended
turbine life as excess soot formation can damage
the protective oxide layer of combustion chamber.
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