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Dimethyl Ether(DME) & Diethyl Ether(DEE) as an

Alternative Fuel

By : Harshit Dhawan (2k12\AE\38)

& Harminder (2k12\AE\037)

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Introduction

World present oil resources may be wiped out in 42 years

Need for clean and pollution free environment.

Diesel engine operated on DME fuel has low combustion noise and low emission.

Fuel is economical and has many utilities.

Variety of choices for raw material sources

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What Are Bio-Ethers Can Be Produced by :

Partial oxidation of biomass to synthesis gas and then to alcohols and then dehydrating them to Ethers using suitable catalysts.

The achievable yield of bio-ether from biomass via the gasification/synthesis gas route is higher than via the hydrolysis/fermentation route.

In gasification/synthesis gas route all carbon can be converted to fuel while in fermentation rout only carbon convertible to sugar can yield fuel.

Bio-Ethers are produced by dehydration of bio based alcohols

Bio-Ethers have superior combustion and emission characteristics as compared to other bio-fuels

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Ethers in Fuel Industry

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Dimethyl Ether (DME)

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MANUFACTURING PROCESS OF DME

Manufactured presently in two methods

1.Catalytic dehydration of methanol to DME

2.Direct synthesis of DME

3CO +3H2 CH3OCH3+CO2

2CH3OH CH3OCH3+H2O

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CHARACTERISTICS OF DME AS A FUEL

Gas at ambient temperature and atmospheric pressure. Colourless clear liquid under six atmospheres. Can be transported and stored as a liquid at low temperatures. No sulphur or nitrogen compounds and low toxicity. No corrosive effect on metals. Oxygenated fuel. Combustion is not accompanied by black smoke or soot.

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PHYSICAL AND CHEMICAL PROPERTIES OF DME AND DIESEL

Comparison Chart

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Engine Studies

Due to expensive production initially DME was considered as ignition improver for other fuels, mainly methanol .

DME has been tested in a number of direct injection diesel engines, ranging in size from 273 to 1220 cm3/cylinder.

In all of these studies, soot-free operation has been observed

NOx emission is found to be generally lower with DME, however some studies have reported equal or even higher NOx emission as compared to diesel

Diagram of fuel supply system of DME engine

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PERFORMANCE AND COMBUSTION CHARACTERSTICS OF DME POWERED VEHICLE

Study was conducted on diesel engine using DME as fuel.

Following parameters were optimized.

1. Plunger diameter.

2. Fuel delivery advance angle.

3. Distance of nozzle tip into cylinder.

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INJECTION PRESSURE: OPTIMUM PRESSURE IS 15 MPA FOR DME

Effect of injection pressure on Thermal Efficiency

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COMBUSTION CHARACTERISTICS

Indicator diagram and rate of pressure rise of DME and diesel engine.

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As a Diesel Fuel Alternative

1. Ideal for use in diesel engines due to same or higher cetane value.

2. Modifications to fuel supply system only is needed.

3. Low soot emissions and greatly reduced NOx emission

4. Thermal efficiency is similar to that of diesel.

5. Reduced noise levels.

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Environmental Concerns Non-Toxic to Humans

Not Carcinogenic and Non Mutagenic

Very Low Reactivity

Short Half- Life in Troposphere

Long, Positive Experience

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Economics of Production

The investment cost for a commercial scale Bio-DME plant

producing 200,000 tons of DME per year has been estimated

at approximately € 390 Millions at a green field location

However, if oxygen and utilities can be purchased “over the

fence” at an industrial site the total investment may be

reduced by about € 100 Millions

For these two location alternatives, the production cost of

Bio-DME has been estimated at € 393 - € 438 per ton of

DME or about € 0.49 - € 0.55 per litre of diesel equivalent

The Bio-DME Project Report to Swedish National Energy Administration, 23April 2002

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1 ton Wood fuel,Generation of all

plant power add. 0.3 tonDME Plant

0.37 ton of DMEIncl. wood for

power generation

0.29 ton/ton

1 GJ LHV Wood fuel,El. Power 0.07 GJ

Generation of all plantpower

add. 0.3 GJ

DMEPlant

0.63 GJ of DME0.58 GJ per GJ in

( wood+ el. power)Incl. wood for

power generation0.49 GJ

Energy efficiency for production of DME from biomass

Yield of DME ton/ton of biomass feed

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Advantages

High Cetane Number

Smokeless combustion

High Volatility

LPG Infrastructur

e can be used for

transportation and

Storage

Disadvantages

Poor Lubrication

And Viscosity

Low Heating Value

High Vapour Pressure

Low Boiling Point

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Conclusion

1. Excellent And Environmental Friendly Alternative Fuel For Diesel Engine

2. Cost of the fuel is much lower than diesel fuel on an equal basis.

3. Relative high cetane number and low soot emissions offset the disadvantages of the fuel for the use in CI engines.

4. It is hoped that the use of DME vehicles will become widespread in the near future.

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Diethyl Ether (DEE)