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APPLICATION OF CATALYTIC CONVERTER

It basically converts harmful gases into harmless gases, whichare environment

friendly, with the help of a catalyst.Engine exhausts having harmful gases like CO, NOx

& HC which are converted into harmless gases like CO2, N2 & H2O respectively with

the use of catalytic converter 

Two-way catalytic converter is widely used on diesel engines to reduce hydrocarbon and

carbon monoxide emissions. They were also used on gasoline engines in American- and

Canadian-market automobiles until 1981. Because of their inability to control oxides of 

nitrogen, 

Three-way (oxidation-reduction) catalytic converters have been used in vehicle emission control

systems in the United States and Canada; many other countries have also adopted stringent

vehicle emission regulations that in effect require three-way converters on gasoline-powered

vehicles. A three-way catalytic converter has three simultaneous tasks:

1.  Reduction of nitrogen oxides to nitrogen and oxygen: 2NOx → xO2 + N2 

2.  Oxidation of carbon monoxide to carbon dioxide: 2CO + O2 → 2CO2 

3.  Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water: CxH2x+2 +

[(3x+1)/2]O2 → xCO2 + (x+1)H2O

The primary use of this element is in automobiles as a catalytic converter, which changes

harmful emissions from the engine into less polluting gases.

Three-way catalytic converters can store oxygen from the exhaust gas stream, usually when the

air-fuel ratio goes lean.When insufficient oxygen is available from the exhaust stream, the stored

oxygen is released and consumed. Alack of sufficient oxygen occurs either when oxygen derived

from NOx reduction is unavailable or when certain maneuvers such as hard acceleration enrich

the mixture beyond the ability of the converter to supply oxygen.

Rhodium-based catalysts are used in a number of industrial processes; notably, in the

automobile catalytic converters and for catalytic carbonylation of methanol to produce acetic

acid by the Monsanto process. It is also used to catalyze addition of hydrosilanes to molecular

double bonds, a process important in manufacture of certain silicone rubbers.Rhodium

catalysts are also used to reduce benzene to cyclohexane. 

. 

Rhodium finds use in  jewelry and for decorations. It is electroplated on white gold and platinum

to give it a reflective white surface. This is known as rhodium flashing in the jewelry business. It

may also be used in coating sterling silver to protect against tarnish, which is silver sulfide 

(Ag2S) produced from the atmospheric hydrogen sulfide (H2S). Solid (pure) rhodium jewelry is

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very rare, because the metal has both high melting point and poor malleability (making such

 jewelry very hard to fabricate) rather than due to its high price. Additionally, iassures that most

of its jewelry usage is in the form of tiny amounts of power (commonly called rhodium sponge)

dissolved into electroplating solutionsts .

  It is also used as a filter in mammography systems because of the characteristic X-rays it

produces.

  Rhodium is also used to coat some parts of high-quality fountain pens due to its high

reflectance, as well as its chemical and mechanical resistance.

  Rhodium neutron detectors are used in combustion engineering nuclear reactors to

measure neutron flux levels – a method that requires a digital filter to determine the

current neutron flux level, as there are three signals generated: immediate, a fewseconds later, and a minute later, each with its own signal level, and all three are

combined in the rhodium detector signals. The three Palo Verde nuclear reactors each

have 305 rhodium neutron detectors, 61 detectors on each of 5 vertical levels, providing

an accurate 3-D "picture" of reactivity and allowing fine tuning to most economically

burn the nuclear fuel.

1. 

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ADVANTAGES OF CATALYTIC CONVERTER

It gives more power .

It gives better performance»

It gives reduced fuel consumption»

Reducing amount of CO, HC and NOx, particulate emission, it leads to pollution free

environment. It is having long life.

  An increase in peak engine horsepower can be achieved.  Gas mileage can be increased in a well designed aftermarket system.

  Aftermarket parts can be cost effective replacements for stock parts when OEM parts are

not readily available (or are more expensive).

  Aftermarket parts are often available in longer lasting stainless steel, whereas many OEM

exhaust components are made from mild steel and have a limited lifespan. 

DISADVANTAGES OF CATALYTIC CONVERTER 

  Cost is high.

  Volume required is high

  Some amount of weight is added

  There is over temperature problem. Heat shields required otherwise areas around it will

beseverely due to thermal stresses. Catalytic material is lost. Unleaded fuel is required

otherwise lead will be replacethe catalyst and so no reactions will be carried out

  Removing or bypassing a catalytic converter may interfere with emission laws in some

 jurisdictions.

  A noticeable increase in noxious fumes may result (particularly when the catalytic

converter is removed or bypassed, and/or when exhaust outlets are rerouted to the side

of the car as with side-exit exhausts).

  Engine sound may be more noticeable to both driver and pedestrians, resulting in

increased noise pollution.

  An incorrectly designed exhaust can cause loss of low-RPM torque, and a decrease in

fuel economy.

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THE FUTURE OF CATALYTIC CONVERTER

The Four-Way Catalytic Converter consists of a three-way catalytic converter and one more

component, which reduces CO2. The different components reduce all known harmful car

emissions.

The newly-designed component uses a completely different process than any of the units of 

the three-way catalytic converter. First the exhaust from the car goes through the three-way

catalytic converter. Then the exhaust goes through a pipe into a chamber containing a fan

on one end. The fan would blow all of the exhaust against a high aluminum content zeolite

on the other end of the chamber. It is a CO2 adsorbent which means that only

CO2 would be let through to the subsequent chamber (University of Oviedo). A CO2 sensor

would be in the pipe leading to the next chamber. Then, when approximately 14.67 grams of 

CO2 are collected in the next chamber, (Toreki) the fan would deactivate, and the excess

exhaust would drift out into the air. These exhausts consist of H2O, N2, and oxygen and are

completely harmless to the environment and humans (Nice). Back in the chamber with theCO2, the chamber would seal itself off to prevent other gases from entering. Then, 16

grams of burning magnesium would be dropped into the chamber from a chute above

(Toreki). The supply of magnesium could be refilled at gas stations like gasoline. The

reaction causes the reactants to reach a temperature of 2000 degrees Celsius(Toreki). As

well, the reaction emits a bright light. Surrounding the chamber are three layers. The

innermost layer is made of a see-through material embedded with quantum dots. When the

quantum dots are manufactured in a certain way, they emit light when heated to a high

temperature (Poole & Owens). The second layer contains a layer of photovoltaic cells

(i.e., solar panels). The third, outermost, layer is an outside shell that contains the entire

assembly. So, when the reaction is initiated by the introduction of magnesium into the

chamber, it heats up the quantum dots and causes the dots to emit light. Then, the light fromthe quantum dots as well as from the reaction itself charges the photovoltaic cells. The

electrical energy generated by the photovoltaic cells goes down a conducting wire to the car

battery, thereby continuously generating energy for the car. The by-products of this reaction

are white magnesium oxide and black carbon. When the reaction is over, the floor of the

reaction chamber opens up so that the byproducts drop down into a collection chamber. The

byproducts could be emptied out at gas stations, where they could be transported to

processing centers that can utilize the byproducts. For instance, white magnesium oxide

can be used to preserve books, and black carbon can act as a substitute for salt in melting

snow. This process is repeated over and over again throughout a car ride.

Quantum dots are found in two aspects of the Four-Way Catalytic Converter: on the inner layer

of the reaction chamber and on the photovoltaic cells. Based on current technologies, when a

light photon hits a photon absorber, it typically releases only one electron. Once it becomes

commercially feasible to manufacture photon absorbers at the quantum scale (i.e., less than 100

nanometers in length, width and height), it has been shown that one photon could release as

many as seven electrons (Jobwerx). This would make the Four-Way Catalytic Converter almost

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seven times more efficient. As well, quantum dots of a heat-resistant material would have to be

manufactured for the inner layer of the reaction chamber. Manufacturers would have to use

extremely acute and fast machines to efficiently mass-produce the quantum dots.

 

CONCLUSION

1- It is found that the reason behind the increase of totalhydrocarbon (THC) in compressed natural gas (CNG)operated vehicle over that produced in gasoline operatedvehicle is due to the difficulty in oxidizing the unburnedhydrocarbons in the exhaust gases, where the oxidizationof hydrocarbons is one of the functions of the three –waycatalyzer. The exhaust hydrocarbons of a gas-operatedvehicle have a significantly different composition to thoseof a gasoline-operated vehicle.2- The effectiveness of catalytic converter (catalyzer) inthe condition of idle state is much better than that fortransient state based on the European Driving Cycle(ECE-15) shown in Figure 3, where in the case of idle

state, the catalyzer is fully warm and hence operating atit's maximum efficiency, while for the case of transientstate condition the effectiveness is not very well, wherethe catalyzer was faced by air flow and temperaturechanges rapidly.3- In the case of catalyst conversion efficiency, thecatalytic converter reduces the amount of both CO andTHC, while increases the amount of CO2 (idle state). Thisis attributed to the fact that the vehicle emission levelsare quite low and the noble metal catalyst required for theTHC emissions would easy remove most of the CO under

these lean conditions. Furthermore, the catalyticconverter is more effective in MPI-gasoline than those forthe other two injection systems (transient state).4- It is hope that the results in this study can help toadopt and developed Cairo driving cycle, which is morerealistic to represent Cairo traffic conditions, and can beused for tests of vehicles running in Cairo in future inorder to report the real world performance of vehicles in

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service. Thus providing information for Egyptian's energyand environmental ministry on how to set up propernational standards for the motor vehicles fuelconsumption and exhaust emissions. It is also hoped thatthe proposed methods could be used for other big cities

as well as for other types of vehicle 

ACKNOWLEDGEMENT

I pay profound greatefulness to my project guide Lecturer prof. L.K. TOKE (Mechanical

Engineering Department) whose guidance & constant motivation led me towards thesucceeful completion of the seminar work . I acknowledge with a deep sense of gratitude,

the encouragement received from them .

Last but not the least I would like to thank all the staff members (Mechanical

Department ) & my friends who helped me directly or indirectly for the successful

completion of this seminar report

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Computer genreted model

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Oxidation & reduction process

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