DIMETHYL ETHER- AN ALTERNATIVE FUEL

INTRODUCTION World present oil resources may be wiped out in 42 years World present oil resources may be wiped out in 42 years Need for clean and pollution free environment. Need for clean and pollution free environment. Diesel engine operated on DME fuel has low combustion noise and low emission. Diesel engine operated on DME fuel has low combustion noise and low emission. Fuel is economical and has many utilities. Fuel is economical and has many utilities. Variety of choices for raw material sources Variety of choices for raw material sources

MANUFACTURING PROCESS OF DME Manufactured presently in two methods 2.Direct synthesis of DME 3CO +3H 2 CH 3 OCH 3 +CO 2 1.Catalytic dehydration of methanol to DME 2CH 3 OH CH 3 OCH 3 +H 2 O

PROCESS FLOW OF LARGE SCALE BENCH PLANT

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

PHYSICAL AND CHEMICAL PROPERTIES OF DME AND DIESEL COMPARISION CHART COMPARISION CHART PROPERTYDMEDIESEL Chemical Formula Boiling Point( 0 c) Liquid Density(gram/Cm 3 ) Liquid Viscosity (Cp) Ignition Temperature (0 c) Cetane Number Latent Heat Of Evaporation (KJ/Kg) Low Heating Value (MJ/Kg) % Wt Of Oxygen CH3-O-CH C3H

Combustion characteristics were compared with those of diesel engine. A DME powered van was developed and its trial operation was carried out on highway. Diagram of fuel supply system of DME engine.

PERFORMANCE AND COMBUSTION CHARACTERSTICS OF DME POWERED VEHICLE Study was conducted on diesel engine using DME as fuel. Study was conducted on diesel engine using DME as fuel. Following parameters were optimised. Following parameters were optimised. 1. Plunger diameter. 2. Fuel delivery advance angle. 3. Distance of nozzle tip into cylinder.

OPTIMIZATION OF PARAMETERS OF COMBUSTION Fuel delivery advanced angle: optimal timing is 19 0 CA BTDC at rated operation conditions and 15 0 CA BTDC at low speed Fuel delivery advanced angle: optimal timing is 19 0 CA BTDC at rated operation conditions and 15 0 CA BTDC at low speed Thermal efficiency maximum at an injection pressure of 15MPa Thermal efficiency maximum at an injection pressure of 15MPa

INJECTION PRESSURE: OPTIMUM PRESSURE IS 15 MPA FOR DME

COMBUSTION CHARACTERISTICS Figure below shows indicator diagram and rate of pressure rise of DME and diesel engine. Figure below shows indicator diagram and rate of pressure rise of DME and diesel engine.

THE COMBUSTION CHARACTERISTICS OF DME AND DIESEL FUEL ARE SHOWN IN FIG BELOW

OPERATIONAL RESULTS OF DME POWER VEHICLE Noise is equivalent to gasoline vehicle below 90 km and smoke free combustion is realized. Noise is equivalent to gasoline vehicle below 90 km and smoke free combustion is realized. Maximum speed and accelerating performance are equivalent to that of diesel operation. Maximum speed and accelerating performance are equivalent to that of diesel operation. No apparent wear was observed by adding some lubricant. No apparent wear was observed by adding some lubricant. Larger amount of mechanical work and smaller amount of wasted internal energy. Larger amount of mechanical work and smaller amount of wasted internal energy.

DME UTILISATION TECHNOLOGY The combustion of DME with municipal gas 13A was done and good combustion was observed.

2.Used 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.

APPLICATIONS Used as an aerosol propellant. Used as an aerosol propellant. Propellant for cosmetic and coating material. Propellant for cosmetic and coating material. Can be used as fuel for power generation. Can be used as fuel for power generation. Raw material for chemical processes. Raw material for chemical processes.

1. Poor Lubrication And Viscosity 2. Low Heating Value 3. No Infrastructure Of Fueling System Of DME 4. High Vapour Pressure 5. Low Boiling Point DISADVANTAGES OF DME FUEL

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.