nox reduction by fuel water emulsion injection

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A SEMINAR ON

NOx REDUCTION BY FUEL WATER EMULSION INJECTION

PRESENTED BY SHAIK NAYEEM ABBAS

UNI:- 3KB04ME046 KBNCE

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Introduction The nitrogen oxide reduction technology

based on fuel water emulsion injection (FWE), developed by MAN B&W Diesel.

More than 95 % of the world’s trade goes by sea and there are approximately 86,000 ocean going merchant ships. About 97 % of them are propelled by large-bore, highly supercharged diesel engines such as shown.

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Formation of NOx Nitrogen oxides (NOx) are formed when

nitrogen (N2) and oxygen (O2) are combined at high temperatures and pressure during the combustion of fuel. All fuels, such as gasoline, diesel, biodiesel, propane, coal, and ethanol, emit NOx when burned.

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Formation of NOx

NOx Formation

prompt NOx fuel NOx thermal NOx

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Prompt NOx Frequently observed in fuel-rich flames and

at low temperatures. Three possible sources:i. Non-equilibrium nascent oxygen (O) and

hydroxyl (OH) radical concentrations accelerate the rate of thermal NO mechanism.

ii. Reactions of hydrocarbon radicals with molecular nitrogen

iii. Reaction of nascent oxygen (O) with molecular nitrogen

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Fuel NOx Form nitrogen bearing fuels such as

certain coals and oil. Can contribute upto 50% of total

emissions when combusting oil As much as 80% when combusting

coal.

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Thermal NOx Is highly temperature dependent. Formed through high temperature

oxidation of the diatomic nitrogen found in combustion air.

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Properties of NOx:

Gas Most nitrogen oxides are odorless NO2 combined with particulate,

appears reddish-brown (smog)

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Harmful effects of NOx Aggravate asthmatic conditions React with the Oxygen in the air to

produce ozone Form nitric acid when dissolved in

water. Cause acid rain Form clouds of smog in the summer

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Emission Reduction techniques

Primary Method Secondary Method Pre Treatment

Method

Fuel Water Emulsion Injection

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1) Primary Method Modification of combustion Modification of Air intake system Exhaust Gas Re-circulation2) Secondary Method Fuel Water Emulsion Injection3) Pre treatment Method Denitration of Fuel Alternative Fuel

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Principle Add water to a fuel The evaporation of water reduces

the temperature maximum in the combustion zone.

The formation of nitrogen oxides is decreased by reduced reaction rates

The actually required water flow is calculated as a function of power

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Method of injection Will provide an emulsified diesel fuel to the

engine’s injector pump, with a water content from 0 to 40%.

Emulsification of the fuel is created mechanically in a fuel-mixing chamber.

Diesel pumped to the fuel-mixing chamber from the fuel tank where water is added to the fuel through a probe controlled by a microprocessor with controlling software.

Mechanical agitation technique results in the breakup of the water into small droplets that are dispersed throughout the diesel fuel, representing an emulsion.

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Diesel engine

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Combustion When liquid is sprayed

into a co-flowing air stream, the spray forms a jet inside the chamber.

The jet consists of evaporating liquid fuel droplets suspended in a hot environment.

Phase slip and temperature gradients exist between the droplets and the surrounding gas, leading to momentum, mass and energy transfer between the two phases.

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Effect on Exhaust Emissions

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%Reduction in NOx Vs Water

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Effect In the engine This technique involves injecting water

using the same injector as the fuel, eliminates the need for an additional fuel injector.

Electronic fuel injection is required to control the injection.

Altering the fuel then water injection process, is likely to come at a significant extra cost.

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Advantages Reduction of nitrogen oxide emissions Reduction of soot emissions Controlling of the water quantity by the

engine parameters Usable in stationary as well as mobile

application

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Disadvantages High initial cost Severe corrosion problem Separate pump for the fuel and water

are needed along with the modification to the fuel delivery line and in the injectors.

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Conclusion-Water Fuel Emulsion Water content to 20%:i. 15-38% NOx reductionii. 1-3% efficiency reduction

Smaller particles: i. Promotes higher NOx reduction ii. Little effect on efficiency reduction

NOx reduction is a function of chamber and flame temperature.

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References I.C.Engine By V.Ganeshan I.C.Engine By Rajput Emulsion and Emulsion Stability by

Johan Siojblom Dynamics of emulsification and de

emulsification of water in crude oil emission by Bhardwaj

MAN B&W Diesel A/S, Copenhagen, Denmark

Emission Control

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Any Questions..???????

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THANK YOU