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ALTERNATIVE FUELS

 ALTERNATIVE FUELS

INTRODUCTION

 Noiseless operation, smooth and higher acceleration and eco friendly operation is the requirement of modern

automobiles. The vehicle powered by an internal combustion engines is having certain disadvantages like noise,

vibrations and limited acceleration due to reciprocating engine mechanism and generation of hazardous elements like

nitrogen oxides (Nx!, carbon monoxide ("!, and unburned #ydro "arbons ($%#"!. To overcome these,

manufacturers are trying different alternative fuels. &ome of the promising alternative fuels are "N', ethanol, methanol,

 propane hydrogen, )series and &olar energy

*ll the alternative fuels reduce ozone)forming tailpipe emissions. The diagram below shows the percentage of 

combined carbon monoxide ("! and nitrogen oxide Nx  emissions for each alternative fuel as compared to

reformulated gasoline (+'!. or example, the emissions from "N' vehicles are estimated to be -/, compared to

0/ emissions from vehicles using +'. "N' vehicles demonstrate an 1/ reduction in ozone)forming emissions.

BRIEF INTRODUCTION ABOUT ALTERNATIVE FUELS

  2ifferent types of alternative fuels available are3)

%iodiesel

4lectricity

4)2iesel (415! and 4thanol based etrol

6ethanol (615 and 60!

#ydrogen

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ALTERNATIVE FUELS

 Natural 'as ("N'78N'!

)series.

ropane (8'!

&olar 4nergy

Biodiesel

The name 9biodiesel9 was introduced in the $nited &tates in 0::- by the National &oy 2iesel 2evelopment

%oard. uels derived from renewable biological resources for use in diesel engines are known as biodiesel fuels. *nimal

fats , virgin and recycled vegetable oils derived from crops such as soybeans, canola, corn and sunflowers can be used

in the production of biodiesel fuel.

  %iodiesel is safe, biodegradable, and reduces serious air pollutants such as particulates, carbon monoxide,

hydrocarbons, and air toxics. %lends of -/ biodiesel with 1/ petroleum diesel (%-! can be used in unmodified

diesel engines, or biodiesel can be used in its pure form (%0!, but may require certain engine modification. %iodiesel

has physical properties very similar to conventional diesel. %iodiesel is better for the environment because it is made

from renewable resources and has lower emissions compared to petroleum diesel. ;t is less toxic than table salt and

 biodegrades as fast as sugar..

Electricity

4lectricity is unique among the alternative fuels in that mechanical power is derived directly from it, whereas

the other alternative fuels release stored chemical energy through combustion to provide mechanical power. 4lectricity

used to power vehicles is commonly provided by batteries, but fuel cells are also being explored. 4lectricity can also be

made from renewable resources using  photovoltaic  or  wind technologies. hotovoltaic solar cells, which directly

convert sunlight into electricity, are made of semi conducting materials. "rystalline silicon (c)&i! is the leading

commercial material for photovoltaic cells. 4lectric alternative fuels do not pollute the environment because it has no

tailpipe emissionsThe cost of an equivalent amount of fuel for electric vehicles is less than the price of gasoline.

Ethanol

The concept of ethanol as a fuel began as early as the first 6odel T car designed by #enry ord. *merican usage of 

ethanol)blended gasoline began in the late 0:<s. 4thanol is a clear, colorless liquid with a characteristic, agreeable

odor. ;n dilute aqueous solution, it has a somewhat sweet flavor, but in more concentrated solutions it has a burning

taste. 4thanol is made from cellulosic biomass materials instead of traditional feedstocks (starch crops! is called

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ALTERNATIVE FUELS

 bioethanol. 4thanol is miscible (mixable! in all proportions with water and with most organic solvents. 4thanol

contains about --,= (high heating value! %T$s per litre

Benefits of ethanol

• ;t reduces air pollution.

• "leaner burning engines

• 8ower net carbon dioxide emissions

Methanol

6ethanol is an alcohol fuel. ;t also called methyl alcohol and wood alcohol. ;t is a derivative of natural gas.

6ethanol is having the same chemical and physical characteristics as that of ethanol. The alternative methanol fuel

currently being used is 6)15. ;n the future, neat methanol, or 6)0, may also be used.o! "ethanol is "ade#

  6ethanol is predominantly produced by steam reforming of natural gas to create a synthesis gas, which is

then fed into a reactor vessel in the presence of a catalyst to produce methanol and water vapor. &ynthesis gas refers to

combinations of carbon monoxide ("! and hydrogen. The synthesis gas is fed into another reactor vessel under high

temperatures and pressures, where " and hydrogen are combined in the presence of a catalyst to produce methanol.

inally, the reactor product is distilled to purify and separate the methanol from the reactor effluent.

ydro$en

The simplest and lightest fuel is hydrogen gas (# -!. #ydrogen uel hydrogen is not pure hydrogen gas. ;t has

small amounts of oxygen and other materials. ure hydrogen and hydrogen mixed with natural gas (hythane! have been

used effectively to power automobiles. #owever, hydrogen>s real potential rests in its future role as fuel for fuel cell

vehicles.

o! is ydro$en Made# 

Two methods are generally used to produce hydrogen3 (0! electrolysis and (-! synthesis gas production from

steam reforming or partial oxidation. (0! 4lectrolysis uses electrical energy to split water molecules into hydrogen and

oxygen. The electrical energy can come from any electricity production sources including renewable fuels. ;t has

concluded that electrolysis is unlikely to become the predominant method for large quantities of hydrogen production in

the future. (-! The predominant method for producing synthesis gas is steam reforming of natural gas, although other 

hydrocarbons can be used as feedstocks. or example, biomass and coal can be gasified and used in a steam reforming

 process to create hydrogen.

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ALTERNATIVE FUELS

Nat%ral &as 'CN&(LN&)

 Natural gas is a mixture of hydrocarbons@mainly methane ("#=!@and is produced either from gas wells or 

in conAunction with crude oil production. The main constituent of natural gas is methane, which is a relatively

unreactive hydrocarbon. ;t is also clean burning and produces significantly fewer harmful emissions than reformulated

gasoline. Natural gas can either be stored on board a vehicle in tanks as compressed natural gas ("N'! or cryogenically

cooled to a liquid state, liquefied natural gas (8N'!.

o! is Nat%ral &as Made# 

'as streams produced from reservoirs contain natural gas liquids and other materials. irst, the gas is separated

from free liquids such as crude oil, hydrocarbon condensate, water, and entrained solids. The separated gas is further 

 processed to meet specified requirements. * dehydration plant controls water contentB a gas processing plant removes

certain hydrocarbon components to hydrocarbon dew point specificationsB and a gas sweetening plant removes

hydrogen sulfide and other sulfur compounds (when present!.

*+Series

)&eries is a new family of liquid fuels that was developed for spark)ignited engines by 2r. &tephen aul of 

rinceton $niversity. )&eries fuel is a unique blend of natural gas liquids (pentanes plus!, ethanol, and a biomass)

derived co)solvent methyl tetra hydro furan (6eT#!. )&eries are designed to be used alone or freely mixed with

gasoline in any proportion. )&eries is made primarily from renewable resources and provides significant emissions

 benefits over reformulated gasoline. The hydrocarbons are mainly 9pentanes plus9, a mixture of - light hydrocarbon

liquids ("5)"1! that are extracted from natural gas. The ethanol is derived from the fermentation of corn. The 6eT# is

derived from two renewable resources that have not been used to produce ethanol3 (0! "ellulosic biomass from waste

 paper, agricultural waste etc. (-! #emicellulosic biomass from sugarcane bagasse etc.

  Benefits 

• )series would be :C/ derived from domestic resources.

•

6ore than C/ of the energy content in )series is derived from renewable sources.

DETAILED DESCRI*TION OF BIODIESEL

"hemically, biodiesel is referred to as the mono alkyl esters of long chain fatty acids derived from renewable

lipid sources. %iodiesel is a methyl or ethyl ester of mainly vegetable oils. 6ethyl or ethyl esters can be produced from

vegetable and tree oils, animal fats, and7or used oils and fats. These oils are blended with an alcohol (usually methanol,

although ethanol can be used as well! and a catalyst such as sodium hydroxide. The resulting chemical reaction (which

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ALTERNATIVE FUELS

occurs at moderate temperatures and pressures! produces an ester and glycerin. 'lycerin is a valuable material used

extensively in the manufacture of soaps and other consumer products. $sing biodiesel in a conventional diesel engine

substantially reduces emissions of unburned hydrocarbons, carbon monoxide, sulfates, polycyclic aromatic

hydrocarbons, nitrated polycyclic aromtic hydrocarbons, and particulate matter. These reductions increase as the amount

of biodiesel blended into diesel fuel increases. The best reductions are seen with %0. 4missions of nitrogen oxides

increase with the  concentration of biodiesel in the fuel %iodiesel can be produced by a variety of esterification

technologies. The oil and fats are filtered and pre)processed to remove water and  contaminants. ;f free fatty acids are

 present, they can be removed or transformed into biodiesel using special ,retreat"ent technolo$y-

*retreat"ent Technolo$y

  +ecycled 'reases

  Degetable il

 &ulphur E

  6ethanol

 

6ethanol E F# 

"rude 'lycerin "rude %iodiesel

 

'lycerin %iodiesel

Transesterfication ,rocess

 *lcohol

  %iodiesel

5

&lycerin

Refinin$  Refinin$

Alcohol

Reco.ery

Dil%te Acid

Esterification

Transesterification

Methanol Reco.ery

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ALTERNATIVE FUELS

Degetableil

  'lycerin

 

"atalyst 6ineral

  *cid

atty acid

  The pretreated oils and fats are then mixed with an alcohol (usually methanol! and a catalyst (usually sodium or 

 potassium hydroxide!. The oil molecules are broken apart and reformed into esters and glycerol, which are then

separated from each other and purified. %iodiesel is made through a chemical process called transesterification

whereby the glycerin is removed from the fat or vegetable oil. The general process transesterification is depicted above

* fat or oil is reacted with an alcohol, like methanol, in the presence of a catalyst to produce glycerine and methyl esters

or biodiesel. The methanol is charged in excess to assist in quick conversion and recovered for reuse. The catalyst is

usually sodium or potassium hydroxide which has already been mixed with the methanol

Biodiesel/s *hysical Characteristics

&pecific gravity .1< to .1:

Finematic viscosity G =H" ?.< to 5.1

#igher heating value (btu7lb! 0C,:-1 to 0<,::C

&ulfur, wt/ . to .-=

"loud point H" )00 to 0C

our point H" )05 to 0?8ower heating value (btu7lb! 05,< to 0C,<?5

Benefits of Biodiesel 

'0) %iodiesel is produced domestically, which helps reduce independence on imported petroleum. '1) ;t is a renewable

fuel. This helps conserve resources and makes the best possible use of materials - '2) %iodiesel blends are competitive

with other alternative fuels on a life)cycle cost basis, because of its lower associated infrastructure costs (no extensive

engine or refueling modifications needed- '3) ;t is considered readily biodegradable in about ? days and non)toxic-

'4) %iodiesel and biodiesel blends significantly reduce harmful tail pipe emissions. '5) +esults indicate reduced engine

wear with a blend of - percent biodiesel and 1 percent conventional diesel.

Disad.anta$es of Biodiesel 

'0) ne study suggested that the production of subsidized biofuels could only be Austified if a high premium is put on

the environmental cost of the alternatives. *lso highlighted was the very poor energy accounting of biofuel production

C

Settler 6ashin$ *%rification E.a,orationReactor

 Neutralization2istillation

&ettler 4vaporation

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ALTERNATIVE FUELS

considering the energy consumed in the manufacture of fertilizers and pesticides to produce the crops plus energy used

in cultivating, harvesting, transporting and processing of the crop.

'1) ne additional concern is the environmental impacts of increased fertilizer and pesticide usage to increase oilseed

 production for use in manufacturing biodiesel.

'2) %iodiesel has a higher viscosity than conventional diesel and therefore becomes less useful at lower temperatures.

DETAILED DESCRI*TION OF ETANOL BASED FUEL

ermenting and distilling starch crops that have been converted into simple sugars produce ethanol an alcohol)

 based alternative fuel. eedstocks for this fuel include corn, barley and wheat. 4thanol can also be produced from

9cellulosic biomass9 such as trees and grasses and is called bioethanol. 4thanol ("# ?"#-#! is a group of chemical

compounds whose molecules contain a hydroxyl group, )#, bonded to a carbon atom. 4thanol can be produced fromany biological feedstocks that contain appreciable amounts of sugar or materials that can be converted into sugar such

as starch or cellulose. &ugar beets and sugar cane are examples of feedstocks that contain sugar. "orn contains starch

that can relatively easily be converted into sugar. * significant percentage of trees and grasses are made up of cellulose,

which can also be converted to sugar, although with more difficulty than required to convert starch. Iymase, an enzyme

from yeast, changes the simple sugars into ethanol and carbon dioxide.

E+Diesel7+

  4)diesel is a blend of standard diesel fuel containing up to 05/ ethanol and a proprietary additive

 package for blend stability and to maintain certain fuel properties such as cetane number and lubricity. *dditives

comprise .-/ to 5/ of the blend. 4thanol)diesel blends (or e)diesel! contain up to 05 volume percent ethanol and an

additive known as an emulsifier or co solvent.

*rod%ction of Ethanol

There are three main uses for ethanol (industrial, beverage and fuel! and the production processes vary slightly

for each of them, but the main steps are the same. 4xamples of industrial uses of ethanol would include ethanol used in

 perfumes, aftershaves and for cleaners. %everage ethanol is used for drinking and must meet strict production standards

 because it will be used for human consumption. 6ost of the ethanol plants in the country utilize a dry milling process.

The maAor steps are outlined below3

0. Millin$7 The corn (or barley or wheat! will first pass through hammer mills, which grind it into a fine powder 

called meal.

-.  Li8%efaction7 The meal will then be mixed with water and alpha)amylase, and will pass through cookers where the

starch is liquefied. #eat will be applied at this stage to enable liquefaction. "ookers with a high temperature stage

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ALTERNATIVE FUELS

(0-)05 degrees "elsius! and a lower temperature holding period (:5 degrees "elsius! will be used. These high

temperatures reduce bacteria levels in the mash.

?.  Saccharification7 The mash from the cookers will then be cooled and the secondary enzyme (gluco)amylase! will be

added to convert the liquefied starch to fermentable sugars (dextrose!, a process called saccharification.

=.  Fer"entation3 Jeast will then be added to the mash to ferment the sugars to ethanol and carbon dioxide. $sing a

continuous process, the fermenting mash will be allowed to flow, or cascade, through several fermenters until the

mash is fully fermented and then leaves the final tank. ;n a batch fermentation process, the mash stays in one

fermenter for about =1 hours before the distillation process is started.

5.   Distillation7 The fermented mash, now called 9beer,9 will contain about 0/ alcohol, as well as all the non)

fermentable solids from the corn and the yeast cells. The mash will then be pumped to the continuous flow, multi)

column distillation system where the alcohol will be removed from the solids and the water. The alcohol will leave

the top of the final column at about :C/ strength, and the residue mash, called stillage, will be transferred from the

 base of the column to the co)product processing area.

DR9 MIILIN& *ROCESS FOR TE *RODUCTION OF ETANOL

1

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ALTERNATIVE FUELS

C- Dehydration7 The alcohol from the top of the column will then pass through a dehydration system where the

remaining water will be removed. 6ost ethanol plants use a molecular sieve to capture the last bit of water in thethanol.

The alcohol product at this stage is called anhydrous (pure, without water! ethanol and is approximately - proofs.

<. Denat%rin$7 4thanol that will be used for fuel is then denatured with a small amount (-)5/! of some product, like

gasoline, to make it unfit for human consumption.

1. Co+*rod%cts3 There are two main co)products created in the production of ethanol3 carbon dioxide and distillers

grain. "arbon dioxide is given off in great quantities during fermentation and many ethanol plants collect that carbon

dioxide, clean it of any residual alcohol, compress it and sell it for use to carbonate beverages or in the flash freezing of 

meat. 2istillers grains, wet and dried, are high in protein and other nutrients and are a highly valued livestock feed

ingredient

CONCLUSION

il is one of the cornerstones of our economy and our national security. ur country now depends on others

nations for < / of the oil we use. KhatLs moreM Transportation accounts for about -7? rd of the oil we consume. This

situation leaves our economy dangerously vulnerable to price shocks and the potential for supply disruptions influences

our options while we respond to terror.

*lternative fuels can help reduce our dependence on foreign oil and help us leverage our fossil fuel supplies.

*ll the time you burn mineral diesel you contribute to global warming, and add toxic wastes to the environment. ;t can

help reduce greenhouse gas emissions, as well as public health risks associated with air pollution. ;t is nontoxic and

 biodegradable. $sing alternative fuels will not add new carbon to the atmosphere.

;t is safe to handle, transport, and store, and has a higher flash point than petroleum diesel. ;t can also be

stored in diesel tanks and pumped with regular equipment except in colder weather, where tank heaters or agitators may

 be required. *lternative fuels mixes readily with petroleum diesel at any blend level, making it a very flexible fuel

additive.

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REFERENCES

BOO:S

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MA&A;INES

*8;D4 ONews 6agazineP

*$T ;N2;*. ONews 6agazineP

6EB

www.google.com

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www.exite.com

www.hotbot.com

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