alternative fuels for commercial aircraft

8/9/2019 Alternative Fuels for Commercial Aircraft

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SEMINAR ON

Alternative fuels for commercialaircrafts

By

Shashishekarayya.R.Hiremath

M.Tech. 1 sem Aeronautical Engg.

M.V.J.C.E Bangalore


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OVERVIEW

yNeed for alternative fuels

y Types of alternatives

yNear term

y Mid term

y Far term

y Conclusion


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NEED FOR ALTERNATIVESy Diminishing discovery of new petroleum sources and

ever increasing demand.


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yNext generation aircrafts will see 15%-20 % fuel efficient,

making air travel one of the most efficient means oftransportion,so aircraft industries will still require an

increasing amount of fuel


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NEAR TERM ALTERNATIVESy Drop in fuels

y Synthetic Jet fuel:

Prepared from Fischer Tropsch process (FT)

Natural gas and coal are main feedstocks


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Positive Attributes:y Cleaner burning fuels with no sulfur

y Higher Thermal Stability

y Lower particulate Engine Emission

y Show excellent low temperature properties

y Maintaining low viscosity at lower temperature


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Negative Attributes:

y Poorer lubrication properties

y Lower volumetric heat content

y Possible contributor to elastomer leakagey Increased CO2 emission during its manufacture


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MID TERM ALTERNATIVES

y 10-25 years from now

y Blending biofuels with synjets

y Some changes in existing engine configuration


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Challenges to be overcome:

y Propensity to freeze at normal operating cruise

temperatures

y Poor high thermal stability characteristics in engine

y Limited excess farm land

One Promising feedstock for bio fuels is Algae.


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FAR TERM ALTERNATIVESyNeed to reduce emissions of greenhouse gases, therefore

low to zero carbon fuels has to be used.

Liquid Methane

Liquid Hydrogen


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Methane Gas

y Huge amounts of methane gas is trapped in the forms of

methane hydrates.

y 0.3 X 1012 m3 in middle east and soviet-union

y 21.1012 m3 in Americas


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Major issues to be considered

y Economics of recovery under unfamiliar & inconvenient

deep under sea conditions.y Environmental and Technical feasibility

y Safety aspects during extraction.

y Extraction in permafrost areas may cause global

warming.


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Liquid Hydrogen

Historical and Technological Evolution of LH2

y The first aircraft that flew with hydrogen was a US Air Force B-57 twin

bomber that in 1956

y In 1988, the Soviets experimented with a modified TU-154 (renamed TU-155), with one engine (out of the two) operated on hydrogen alone.

y Retired Pan American pilot Bill Conrad converted a four seater Grutnnab

Cheetah to run on hydrogen in 1988.

y During the 1989 Paris Air Show, the German partner in the European

Airbus, Messerschmidt-Boelkkov-lBlohm (MBB), showed an interest indeveloping a hydrogen fueled twin of the Airbus A310.

y Samara Trud Project (Samara State Scientific and Production Enterprise

(SSSPE) TRUD),


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y cryoplane design adopted by

Russian-German

Cooperative Venture on the

basis of an existing Airbus

A310

y NASA-Langley Research

Center


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LH2 advantage

y Higher specific energy (119 190 kJ/kg) than conventional fuel (43 60

kJ/kg). Higher fuel efficiency. Wider range of flammability.

y Higher flame speed. Higher combustion temperature.

y Reduced gross weight (26%). Reduced wing area (18%). Smaller engines

and noise reduction. High heat sink capacity. Cruise lift-to-drag ratio

reduced by 10-18%.

y NO missions of CO, CO*, particles, HC, S compounds and odor. Reduced

NO, (33% or less of that produced by todays turbofan engines using

combustion chambers with premixing)


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LH2 disadvantage

y Four times lower energy per unit volume.

y More voluminous fuselage. Necessity of cryogenic fuel

system.y Airport hydrogen plant with following units needed:

Electrolyzer, purification, liquefier, storage and

distribution system About 2.5 times more H2O


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Environmental considerations

y Production of Nox

y Green house effect of water vapor increases enormously.

y Hydrogen is the most advantageous environmental optionover carbon based fuels, since it does not produce CO2CO, SO2, HC, etc., and lowers NOx emission.


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afety and handling

y Hydrogen is an extremely volatile fuel, which has to be

handled with great care. Never the less it is not unsafe.

yplacement of fuel tanks.

y Hydrogen has a wide flammability range.

y Liquid hydrogen, along with other cryogens, has a high

liquid-to-gas volume expansion ratio, so that liquid

hydrogen piping should always include a pressure reliefdevice.


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Economics ofLH 2 aircraft

y LH2 aircraft, the most influential factor is the fuel cost,

representing 50% of the total DOC.

yLH2price will decrease as large scale industrial facilitiesare installed.

yNeed to build industrial facilities for LH2production.


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CONCLUSIONy The short-term option of synthetic fuels processed in the

FT process meets the first target, , it will not reduce CO2

emissions over the entire life cycle.y Algae seem to be a promising future feedstock option

which could provide a much higher oil yield per hectare

than present bio-fuels.

yThe large scale introduction of hydrogen into aviation

presents no unsolvable technical problems, but it does

involve the need for the following work items:


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y A thorough study of the components of a cryogenic fuel

system, mainly as regards the structural materials for

tanks, pipes and insulation systems.y Developing monitoring systems to detect hydrogen leaks

in hydrogen installations.

y Research on reducing NOx emissions.


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QUESTIONSuu


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THANK YOU

alternative fuels for commercial aircraft

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