wikipedia - presentation of an oil refinery.doc

8/20/2019 Wikipedia - Presentation of an oil refinery.doc

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Presentation of an oil renery

Source: Wikipedia, the free encyclopedia (www.wikipedia.com)

View of the Tosco (ex Valero, originally Shell) artine! oil re"nery

Denition

#n oil re"nery is an industrial process plant where crude oil is processed andre"ned into useful petroleum products.

Contents

1. Operation2. Products of oil renery3. Safety and environmental concerns

4. Common process units found in a renery5. Specialized end product units. Co!plant sitin"#. $istory%. See also&. '(ternal lin)s

1. Operation

$aw oil or unprocessed (%crude%) oil is not &ery useful in the form it comes in outof the ground. 't needs to e roken down into parts and re"ned efore use in asolid material such as plastics and foams, or as petroleum fossil fuels as in the

case of automoile and airplane engines.il can e used in so many &arious ways ecause it contains hydrocarons of &arying molecular masses and lengths such as para*ns, aromatics, naphthenes(or cycloalkanes), alkenes, dienes, and alkynes.

http://www.wikipedia.com/http://www.wikipedia.com/


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+rude oil is separated into fractions y fractional distillation. The hea&ierfractions that merge from the ottom of the fractionating column are oftenroken up (cracked) to make more useful products.ydrocarons are molecules of &arying length and complexity made of hydrogenand caron. Their &arious structures gi&e them their di-ering properties andtherey uses. The trick in the oil re"nement process is separating and purifyingthese. #ll these di-erent hydrocarons ha&e a di-erent oiling point, whichmeans they can e separated y distillation.nce separated and any contaminants and impurities ha&e een remo&ed, the oilcan e either sold without any further processing, or smaller molecules such asisoutane and propylene or utylenes can e recomined to meet speci"c octanereuirements y processes such as alkylation or less commonly, dimeri!ation.ctane can also e impro&ed y catalytic reforming, which strips hydrogen out of hydrocarons to produce aromatics, which ha&e much higher octane ratings.'ntermediate products such as gasoils can e&en e reprocessed to reak hea&y,long/chained oil into lighter short/chained oil, y &arious forms of cracking suchas 0luid +atalytic +racking, Thermal +racking, and ydrocracking. The "nal stepin gasoline production is the lending of fuels with di-erent octane ratings, &aporpressures and other properties to meet product speci"cations.

2. Products of oil renery

• #sphalt

• 1iesel fuel• 0uel oils

• 2asoline

• 3erosene

• 4iuid petroleum gas (452)

• 4uricating oils

• 5ara*n wax

• Tar

3. Safety and environmental concerns


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il re"neries can ecome &ery largeand sprawling complexes with &astnumers of pipes running throughoutthe facility. The re"ning process cancause many di-erent chemicals to ereleased into the atmosphere /conseuently a notale odor mayaccompany the presence of a re"nery.6n&ironmental groups ha&e loiedmany go&ernments to increaserestrictions on how much materialre"neries can release, and manyre"neries ha&e installed euipmentand changed practices to lessen the

en&ironmental impact. 'n the 7nited States, there is strong pressure to pre&entthe de&elopment of new re"neries, and none ha&e een uilt in the country for

more than three decades. any existing re"neries ha&e een expanded duringthat time howe&er.6n&ironmental and safety concerns mean that oil re"neries are usually located asafe distance away from ma8or uran areas. 9e&ertheless, there are potentiallydangerous exceptions to this rule, a particularly notale one eing the Santa +ru!re"nery (Tenerife, Spain), which is sited in a densely/populated city center andnext to the only two ma8or e&acuation routes in and out of the city.

4. Common process units found in a renery

• #tmospheric 1istillation 7nit: distills crude oil into fractions;

• Vacuum 1istillation 7nit: further distills residual ottoms after atmosphericdistillation;

• 9aphtha ydrotreater 7nit: desulfuri!es naphtha from atmosphericdistillation;

• +atalytic $eformer 7nit: uses hydrogen to reak long chain hydrocaronsinto lighter elements that are added to the distiller feedstock;

• 1istillate ydrotreater 7nit: desulfuri!es distillate (diesel) afteratmospheric distillation;

• 0luid +atalytic +on&erter 7nit

• 1imeri!ation 7nit

• 'someri!ation 7nit

•

2as storage units for propane and similar gaseous fuels at pressuresu*cient to maintain in liuid form / these are usually spherical• Storage tanks for crude oil and "nished products, usually cylindrical, with

some sort of &apor enclosure and surrounded y an earth erm to containspills

5. Specialized end product units

These units will lend &arious feedstocks, mix appropriate additi&es, pro&ideshort term storage, and prepare for ulk loading to trucks, arges, product ships,and railcars.

• 2aseous fuels such as propane are stored and shipped in liuid form underpressure in speciali!ed railcars to distriutors.


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• 4iuid fuels lending (producing automoti&e and a&iation grades of gasoline, kerosene, &arious a&iation turine fuels, and diesel fuels, addingdyes, detergents, antiknock additi&es, oxygenates, and anti/fungalcompounds as reuired). Shipped y arge, rail, and tanker ship. ay eshipped regionally in dedicated pipelines to point consumers, particularly

a&iation 8et fuel to ma8or airports, or piped to distriutors in multi/productpipelines using product separators called %pigs%.• 4uricants (produces light machine oils, motor oils, and greases, adding

&iscosity staili!ers as reuired), usually shipped in ulk to an o-sitepackaging plant.

• Wax, used in the packaging of fro!en foods, among others. ay e shippedin ulk to a site to prepare as packaged locks.

• Sulfuric acid "nishing and shipping. This is a useful industrial material,usually prepared as oleum, a yproduct of sulfur remo&al from fuels.

•


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Crac)in" *c+emistry,

'n petroleum geology and chemistry, cracking is the process wherey complexorganic molecules (e.g. kerogens or hea&y hydrocarons) are con&erted tosimpler molecules (e.g. light hydrocarons) y the reaking of caron/caron

onds in the precursors. The rate of cracking and the end products are stronglydependent on the temperature and presence of any catalysts.

Contents

1. -pplications1.1. luid Catalytic Crac)in"1.2.$ydrocrac)in"1.3.Steam Crac)in"

2. C+emistry2.1. Catalytic Crac)in"2.2. /+ermal Crac)in"

3. $istory

1. -pplications

'n an oil re"nery cracking processes allow the production of %light% products (suchas 452 and gasoline) from hea&ier crude oil distillation fractions (such as gas oils)and residues. 0luid +atalytic +racking (0++ for short) produces a high yield of gasoline and 452 while hydrocracking is a ma8or source of 8et fuel, gasolinecomponents and 452. Thermal cracking is currently used to %upgrade% &ery hea&yfractions (%upgrading%, %&isreaking%), or to produce light fractions or distillates,urner fuel andIor petroleum coke. Two extremes of the thermal cracking in termsof product range are represented y the high/temperature process called steamcracking or pyrolysis (ca. F@H to BHH J+ or more) which produces &alualeethylene and other feeds for the petrochemical industry, and the milder/temperature delayed coking (ca. @HH J+) which can produce, under the rightconditions, &aluale needle coke, a highly crystalline petroleum coke used in theproduction of electrodes for the steel and aluminum industries.

1.1. luid Catalytic Crac)in"

0luid catalytic cracking is a commonly used process and a modern oil re"nery willtypically include a cat cracker, particularly re"neries in the 7S# due to the highdemand for gasoline. The process was "rst used in around BCG, and employs a

powdered catalyst. 'nitial process implementations were ased on a low acti&ityalumina catalyst and a reactor where the catalyst particles were suspended in arising Kow of feed hydrocarons in a Kuidi!ed ed.'n newer designs, cracking takes place using a &ery acti&e !eolite/ased catalystin a short/contact time &ertical or upward sloped pipe called the %riser%. 5re/heated feed is sprayed into the ase of the riser &ia feed no!!les where itcontacts extremely hot Kuidi!ed catalyst at GDH to CHH J0 (AA@ to FAH J+). Thehot catalyst &apori!es the feed and cataly!es the cracking reactions that reakdown the high molecular weight oil into lighter components including 452,gasoline, and diesel. The catalyst/hydrocaron mixture Kows upward through theriser for 8ust a few seconds and then the mixture is separated &ia cyclones. Thecatalyst/free hydrocarons are routed to a main fractionator for separation intofuel gas, 452, gasoline, light cycle oils used in diesel and 8et fuel, and hea&y fueloil.


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1uring the trip up the riser, the cracking catalyst is %spent% y reactions whichdeposit coke on the catalyst and greatly reduce acti&ity and selecti&ity. The%spent% catalyst is disengaged from the cracked hydrocaron &apors and sent toa stripper where it is contacted with steam to remo&e hydrocarons remaining inthe catalyst pores. The %spent% catalyst then Kows into a Kuidi!ed/edregenerator where air (or in some cases air plus oxygen) is used to urn o- thecoke to restore catalyst acti&ity and also pro&ide the necessary heat for the nextreaction cycle, cracking eing an endothermic reaction. The %regenerated%catalyst then Kows to the ase of the riser, repeating the cycle.

The gasoline produced in the 0++ unit has an ele&ated octane rating ut is lesschemically stale compared to other gasoline components due to its ole"nicpro"le. le"ns in gasoline are responsile for the formation of polymeric depositsin storage tanks, fuel ducts and in8ectors. The 0++ 452 is an important source of +D/+C ole"ns and isoutane that are essential feeds for the alkylation process.

1.2.$ydrocrac)in"

ydrocracking is a catalytic cracking process assisted y the presence of anele&ated partial pressure of hydrogen. The products resulted are saturatedhydrocarons; depending on the process se&erity (temperature, pressure,catalyst acti&ity) these products range from ethane, 452 to hea&ier hydrocaronscomprising mostly of isopara*ns. ydrocracking is normally facilitated y aifunctional catalyst that is capale of rearranging and reaking hydrocaronchains as well as adding hydrogen to aromatics and ole"ns to producenaphthenes and alkanes.a8or products from hydrocracking are 8et fuel, relati&ely high octane ratinggasoline fractions and 452. #ll these products ha&e a &ery low content of sulfurand contaminants.

1.3.Steam Crac)in"

Steam cracking is a petrochemical process in which saturated hydrocarons areroken down into smaller, often unsaturated, hydrocarons. 't is the principalindustrial method for producing the lighter alkenes (or commonly ole"ns),including ethene (or ethylene) and propene (or propylene).'n steam cracking, a gaseous or liuid hydrocaron feed is diluted with steam andthen rieKy heated in a furnace. Typically, the reaction temperature is &ery hotLo&er BHHJ+Lut the reaction is only allowed to proceed for a few tenths of asecond efore eing uenched y contact with a colder Kuid.

The products produced in the reaction depend on the composition of the feed,

the hydrocaron to steam ratio and on the cracking temperature M furnaceresidence time. 4ight hydrocaron feeds (such as ethane, 452s or light naphthas)gi&e product streams rich in the lighter alkenes, including ethylene, propylene,and utadiene. ea&ier hydrocaron (full range M hea&y naphthas as well asother re"nery products) feeds gi&e some of these, ut also gi&e products rich inaromatic hydrocarons and hydrocarons suitale for inclusion in gasoline or fueloil. The higher cracking temperature (also referred to as se&erity) fa&ours theproduction of ethene and en!ene, whereas lower se&erity produces relati&elyhigher amomunts of propene, +C/hydrocarons and liuid products.

The process also results in the slow deposition of coke, a form of caron, on thereactor walls. This degrades the e-ecti&eness of the reactor, so reactionconditions are designed to minimi!e this. 9onetheless, a steam cracking furnace

can usually only run for a few months at a time etween de/cokings.


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2. C+emistry

%+racking% reaks larger molecules into smaller ones. This can e done with athermic or catalytic method. The thermal cracking process follows a homolyticmechanism, that is, onds reak symmetrically and thus pairs of free radicals areformed. The catalytic cracking process in&ol&es the presence of acid catalysts(usually solid acids such as silica/alumina and !eolites) which promote aheterolytic (asymmetric) reakage of onds yielding pairs of ions of oppositecharges, usually a carocation and the &ery unstale hydride anion. +aron/locali!ed free radicals and cations are oth highly unstale and undergoprocesses of chain rearrangement, +/+ scission in position eta (i.e., cracking)and intra/ and intermolecular hydrogen transfer or hydride transfer. 'n oth typesof processes, the corresponding reacti&e intermediates (radicals, ions) arepermanently regenerated, and thus they proceed y a self/propagating chainmechanism. The chain of reactions is e&entually terminated y radical or ionrecomination.

2.1. Catalytic Crac)in"

+atalytic cracking uses a catalyst to aid the process of reaking down largehydrocaron molecules into smaller ones. 1uring this process, less reacti&e andtherefore more stale and longer li&ed intermediate cations accumulate on thecatalysts= acti&e sites generating deposits of caronaceous products generally(and in many cases inappropriately) known as coke. Such deposits need to eremo&ed (usually y controlled urning) in order to restore catalyst acti&ity.

2.2. /+ermal Crac)in"

'n thermal cracking ele&ated temperatures are used. #n o&erall process of disproportionation can e oser&ed, where %light%, hydrogen/rich products areformed at the expense of hea&ier molecules which condense and are depleted of hydrogen.

# large numer of chemical reactions take place during steam cracking, most of them ased on free radicals. +omputer simulations aimed at modeling what takesplace during steam cracking ha&e included hundreds or e&en thousands of reactions in their models. The ma8or sorts of reactions that take place, withexamples, include:

•

'nitiation reactions, where a single molecule reaks apart into two freeradicals. nly a small fraction of the feed molecules actually undergoinitiation, ut these reactions are necessary to produce the free radicalsthat dri&e the rest of the reactions. 'n steam cracking, initiation usuallyin&ol&es reaking a chemical ond etween two caron atoms, rather thanthe ond etween a caron and a hydrogen atom.

• +D+D N G +DO

• ydrogen astraction, where a free radical remo&es a hydrogen atom fromanother molecule, turning the second molecule into a free radical.

• +DO P +D+D N +C P +D+GO


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• $adical decomposition, where a free radical reaks apart into twomolecules, one an alkene, the other a free radical. This is the process thatresults in the alkene products of steam cracking.

• +D+GO N +GQ+G P O

•

$adical addition, the re&erse of radical decomposition, in which a radicalreacts with an alkene to form a single, larger free radical. These processesare in&ol&ed in forming the aromatic products that result when hea&ierfeedstocks are used.

• +D+GO P +GQ+G N +D+G+G+GO

• Termination reactions, which happen when two free radicals react witheach other to produce products that are not free radicals. Two commonforms of termination are recomination, where the two radicals comine toform one larger molecule, and disproportionation, where one radicaltransfers a hydrogen atom to the other, gi&ing an alkene and an alkane.

• +DO P +D+GO N +D+G+D

• +D+GO P +D+GO N +GQ+G P +D+D

3. $istory

The "rst thermal cracking method, the


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0asoline

5etrol (petroleum spirit) redirects here. 0or the seaird, see petrel, spelled with an=e=.2asoline, as it is known in 9orth #merica, or petrol (are&iated from petroleum

spirit), in many +ommonwealth countries (sometimes also called motor spirit) is apetroleum/deri&ed liuid mixture consisting primarily of hydrocarons, used asfuel in internal comustion engines. The term gasoline is commonly used withinthe oil industry, e&en within companies that are not #merican. The word%gasoline% is commonly shortened in collouial usage to %gas% (see othermeanings). The term mogas, short for motor gasoline, for use in cars is used todistinguish it from a&gas, a&iation gasoline used in (light) aircraft. This should edistinguished in usage from genuinely gaseous fuels used in internal comustionengines such as 452.

Contents

1. C+emical analysis and production1.1. olatility1.2.Octane ratin"

2. Dan"ers

3. 'ner"y content

4. -dditives4.1. ead4.2. /4.3. O(y"enate lendin"

5. $istory5.1. P+armaceutical5.2.'tymolo"y5.3. orld ar 66 and octane

. Current use

1. C+emical analysis and production

2asoline is produced in oil re"neries. These days, material that is simplyseparated from crude oil &ia distillation, called natural gasoline, will not meet thereuired speci"cations (in particular octane rating; see elow) for modernengines, ut these streams will form part of the lend.

The ulk of a typical gasoline consists of hydrocarons with etween @ and Gcaron atoms per molecule.

The &arious re"nery streams that are lended together to make gasoline all ha&edi-erent characteristics. Some important streams are:

• $eformate, produced in a catalytic reformer with a high octane and higharomatics content, and &ery low ole"ns (alkenes).


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• +at +racked 2asoline or +at +racked 9aphtha, produced from a catalyticcracker, with a moderate octane, high ole"ns (alkene) content, andmoderate aromatics le&el. ere, %cat% is short for %catalyst%.

• ydrocrackate (ea&y, id, and 4ight), produced from a hydrocracker, withmedium to low octane and moderate aromatic le&els.

•

9atural 2asoline (has &ery many names), directly from crude oil with lowoctane, low aromatics (depending on the crude oil), some naphthenes(cycloalkanes) and !ero ole"ns (alkenes).

• #lkylate, produced in an alkylation unit, with a high octane and which ispure para*n (alkane), mainly ranched chains.

• 'somerate (&arious names) which is made y isomerising 9atural 2asolineto increase its octane rating and is &ery low in aromatics and en!enecontent.

9ote: The terms used here are not always the correct chemical terms. Typicallythey are old fashioned, ut they are the terms normally used in the oil industry.

The exact terminology for these streams &aries y oil company and y country.

&erall a typical gasoline is predominantly a mixture of para*ns (alkanes),naphthenes (cycloalkanes), aromatics and ole"ns (alkenes). The exact ratios candepend on:

• the oil re"nery that makes the gasoline, as not all re"neries ha&e the sameset of processing units.

• the crude oil used y the re"nery on a particular day.

• the grade of gasoline, in particular the octane.

These days, gasoline in many countries has tight limits on aromatics in general,en!ene in particular, and ole"ns (alkene) content. This is increasing the demand

for high octane pure para*n (alkane) components, such as alkylate, and isforcing re"neries to add processing units to reduce the en!ene content.

2asoline can also contain some other organic compounds: such as organicethers, (delierately added) plus small le&els of contaminants, in particular sulfurcompounds such as disul"des and thiophenes. Some contaminants, in particularmercaptans and hydrogen sul"de must e remo&ed ecause they cause corrosionin engines.

1.1. olatility

2asoline is more &olatile than diesel or kerosene, not only ecause of the aseconstituents, ut ecause of the additi&es that are put into it. The "nal control of &olatility is often &ia lending of utane. The desired &olatility depends on theamient temperature: 'n hotter climates, gasoline components of highermolecular weight and thus lower &olatility are used. 'n #ustralia the &olatility limitchanges e&ery month and di-ers for each main distriution center, ut mostcountries simply ha&e a summer, winter and perhaps intermediate limit.

The maximum &olatility of gasoline in many countries has een reduced in recentyears to reduce the fugiti&e emissions during refueling.Volatility standards may e relaxed (allowing more gasoline components into theatmosphere) during emergency anticipated gasoline shortages. 0or example, onD #ugust GHH@ in response to urricane 3atrina, the 7nited States acti&ated an

early switch to %winter gasoline% which has a &olatility limit exceeding the usualsummertime standard. #s mandated y 65# administrator Stephen 4. Rohnson,


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this %fuel wai&er% was made e-ecti&e through @ Septemer GHH@. Thoughrelaxed &olatility standards negati&ely impact o!one and other air uality criteria,higher &olatility gasoline (which contains less additi&es than gasoline whose&olatility has een arti"cially lowered) essentially increases a nation=s gasolinesupply.

1.2.Octane ratin"

The most important characteristic of gasoline is its octane rating, which is ameasure of how resistant gasoline is to premature detonation (knocking). 't ismeasured relati&e to a mixture of G,G,C/trimethylpentane (an isomer of octane)and n/heptane. #n ?F/octane gasoline has the same knock resistance as amixture of ?F isooctane and D n/heptane. The octane rating system wasde&eloped y the chemist $ussell arker.

2. Dan"ers

any of the non/aliphatic hydrocarons naturally present in gasoline (especiallyaromatic ones like en!ene), as well as many anti/knocking additi&es, arecarcinogenic.


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gasohol (H ethanol P BHgasoline)

G?.HA C@,GHH GH,BHH BDIBC

diesel CH.B FA,HHH CF,HHH 9I# (seecetane)

# high octane fuel such as 452 has a lower energy content than lower octane

gasoline, resulting in an o&erall lower power output at the regular compressionratio an engine ran at on gasoline. owe&er, with an engine tuned to the use of 452 (ie. &ia higher compression ratios such as G: instead of ?:), this lowerpower output can e o&ercome. This is ecause higher/octane fuels allow for ahigher compression ratio / this means less space in a cylinder on its comustionstroke, hence a higher cylinder temperature, less wasted hydrocarons (thereforeless pollution and wasted energy), and therefore higher power le&els coupled withless pollution o&erall ecause of the greater e*ciency.9ote that the main reason for the lower energy content (per litre) of 452 incomparison to gasoline is that is has a lower density. 6nergy content per kilogramis higher than for gasoline (higher hydrogen to caron ratio). 'n lay terms, we

urn mass, not &olume#s an interesting side note di-erent countries ha&e some &ariation in what $9 isstandard for gasoline, or petrol. 'n the 73, ordinary premium unleaded petrol isalways B@ $9 whereas super unleaded is usually BF/B? $9. 'n the 7S, octaneratings in fuels can &ary etween ?F #3' (BG $9) for regular, through BH (B@) formid/grade (6uropean 5remium), up to BDIBC for premium unleaded or 6H (Superin 6urope)

4. -dditives

4.1. ead

The mixture known as gasoline when used in high compression internalcomustion engines, has a tendency to explode early ( pre/ignition pre/detonation) causing a disturing %engine knocking% (also called %pinging%) noise.6arly research into this e-ect was led y #.. 2ison and arry $icardo in6ngland and Thomas idgley and Thomas


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# side e-ect of the lead additi&es was protection of the &al&e seats from erosion.any classic car=s engines ha&e needed modi"cation to use lead/free fuels sinceleaded fuels ecame una&ailale.2asoline, as deli&ered at the pump, also contains additi&es to reduce internalengine caron uildups, impro&e comustion, and to allow easier starting in coldclimates.

4.2. /

ethylcyclopentadienyl manganese tricaronyl (T) has een used for manyyears in +anada and recently in #ustralia to oost octane. 't also helps old carsdesigned for leaded fuel run on unleaded fuel without need for additi&es topre&ent &al&e prolems.

There are currently ongoing deates as to whether or not T is harmful to theen&ironment and toxic to humans.

4.3. O(y"enate lendin"

xygenate lending adds oxygen to the fuel in oxygen/earing compounds suchas T


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5.1. P+armaceutical


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compression deli&ered y the superchargers. The 2ermans, relying entirely on%good% gasoline, had no such industry, and instead had to rely on e&er/largerengines to deli&er more power.owe&er, 2erman a&iation engines were of the direct fuel in8ection type andcould use methanol/water in8ection and nitrous oxide in8ection, which ga&e @Hmore engine power for "&e minutes of dog"ght. This could e done only "&etimes or after CH hours run/time and then the engine would ha&e to e reuilt.ost 2erman aero engines used ?F octane fuel (called


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Diesel

This article is aout the fuel. 0or other uses see diesel (disamiguation)1iesel or 1iesel fuel is a speci"c fractional distillate of fuel oil (mostly petroleum)that is used as fuel in a diesel engine in&ented y 2erman engineer $udolf 1iesel.

The term typically refers to fuel that has een processed from petroleum, utincreasingly, alternati&es such as iodiesel or iomass to liuid (


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1iesel fuel, howe&er, often contains higher uantities of sulfur. 'n 6urope,emission standards and preferential taxation ha&e oth forced oil re"neries todramatically reduce the le&el of sulfur in diesel fuels. 'n contrast, the 7nitedStates has long had %dirtier% diesel, although more stringent emission standardsha&e een adopted with the transition to ultra/low sulfur diesel (74S1) occurringin GHHA (see also diesel exhaust). 7S diesel fuel typically also has a lower cetanenumer (a measure of ignition uality) than 6uropean diesel, resulting in worsecold weather performance and some increase in emissions.

igh le&els of sulfur in diesel are harmful for the en&ironment. 't pre&ents the useof catalytic diesel particulate "lters to control diesel particulate emissions, as wellas more ad&anced technologies, such as nitrogen oxide (9x) adsorers (stillunder de&elopment), to reduce emissions. owe&er, lowering sulfur also reducesthe luricity of the fuel, meaning that additi&es must e put into the fuel to helpluricate engines.


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4. 8ses

1iesel fuel is &ery similar to heating oil which used in central heating. 'n oth6urope and the 7nited States, taxes on diesel fuel are higher than on heating oil,and in those areas, heating oil is marked with dye and trace chemicals to pre&entand detect tax fraud. Similarly, %untaxed% diesel is a&ailale in the 7nited States,which is a&ailale for use primarily in agricultural applications such as for tractorfuel. This untaxed diesel is also dyed red for identi"cation purposes, and should aperson e found to e using this untaxed diesel fuel for a typically taxed purpose(such as %o&er/the/road%, or dri&ing use), the user can e "ned YH,HHH 7S1 onthe spot. #lso, in the 7nited 3ingdom and 'reland it is known as red diesel, and isalso used y agricultural &ehicles. The term 16$V (short for %diesel engined road&ehicle%) is also used in the 73 as a synonym for diesel fuel.

1iesel is used in diesel engines, a type of internal comustion engine. $udolf 1iesel originally designed the diesel engine to use coal dust as a fuel, ut oilpro&ed more e-ecti&e. 1iesel engines are used in cars, trucks, motorcycles, oats

and locomoti&es.5ackard diesel motors were used in aircraft as early as BGF, and +harles4indergh Kew a Stinson S< with a 5ackard 1iesel in BG?. # 5ackard dieselmotor designed y 4.. Woolson was "tted to a Stinson ZFA@C, and in BGB itwas Kown HHH km non/stop from 1etroit to 4angley, V#. 'n BD, Walter 4eesand 0redrick


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isc+er!/ropsc+ process

The 0ischer/Tropsch process is a cataly!ed chemical reaction in which caronmonoxide and hydrogen are con&erted into liuid hydrocarons of &arious forms.

Typical catalysts used are ased on iron and coalt. The principal purpose of this

process is to produce a synthetic petroleum sustitute.

Contents9

1. Ori"inal process2. $istory3. 8tilization

1. Ori"inal process

The original 0ischer/Tropsch process is descried y the following chemical

euation:

The mixture of caron monoxide and hydrogen is called synthesis gas or syngas. The resulting hydrocaron products are re"ned to produce the desired syntheticfuel.

The caron dioxide and caron monoxide is generated y partial oxidation of coaland wood/ased fuels. The utility of the process is primarily in its role inproducing Kuid hydrocarons or hydrogen from a solid feedstock, such as coal orsolid caron/containing wastes of &arious types. 9on/oxidati&e pyrolysis of thesolid material produces syngas which can e used directly as a fuel without eingtaken through 0ischer/Tropsch transformations. 'f liuid petroleum/like fuel,luricant, or wax is reuired, the 0ischer/Tropsch process can e applied. 0inally, if hydrogen production is to e maximi!ed, the water gas shift reaction can eperformed, generating only caron dioxide and hydrogen and lea&ing nohydrocarons in the product stream. 0ortunately shifts from liuid to gaseousfuels are relati&ely easy to make.

2. $istory

Since the in&ention of the original process y the 2erman researchers 0ran!0ischer and ans Tropsch, working at the 3aiser Wilhelm 'nstitute in the BGHs,many re"nements and ad8ustments ha&e een made, and the term %0ischer/

Tropsch% now applies to a wide &ariety of similar processes (0ischer/Tropschsynthesis or 0ischer/Tropsch chemistry)

The process was in&ented in petroleum/poor ut coal/rich 2ermany in the BGHs,to produce liuid fuels. 't was used y 2ermany and Rapan during World War '' toproduce alternati&e fuels. 2ermany=s yearly synthetic oil production reachedmore than BH million tons in BCC. #fter the war captured 2erman scientistscontinued to work on synthetic fuels in the 7nited States in peration 5aperclip.


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3. 8tilization

+urrently, two companies ha&e commercialised their 0T technology. Shell in


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7iodiesel


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1. $istory

Transesteri"cation of a &egetale oil was conducted as early as ?@D, yscientists 6. 1u-y and R. 5atrick, many years efore the "rst diesel engineecame functional. $udolf 1iesel=s prime model, a single H ft (D m) iron cylinderwith a Kywheel at its ase, ran on its own power for the "rst time in #ugsurg,2ermany on #ugust H, ?BD. 'n rememrance of this e&ent, #ugust H has eendeclared 'nternational


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reuirements for iodiesels are "xed in a 1'9 standard. There are standards forthree di-erent &arieties of iodiesel, which are made of di-erent oils:

• $6 (rapeseed methyl ester, according to 1'9 6 @AHA)

• 56 (&egetale methyl ester, purely &egetale products, according to 1'96 @AHA)

•

06 (fat methyl ester, &egetale and animal products, according to 1'9 V@AHA)

The standards ensure that the following important factors in the fuel productionprocess are satis"ed:

• +omplete reaction.

• $emo&al of glycerin.• $emo&al of catalyst.

• $emo&al of alcohol.

• #sence of free fatty acids.


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•


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3.1.7ase oils

Soyeans are used as a source of iodiesel

# &ariety of iolipids can e used to produce iodiesel. These include:• Virgin oil feedstock; rapeseed and soyean oils are most commonly used,

though other crops such as mustard, palm oil, hemp and e&en algae showpromise;

• Waste &egetale oil (WV);

• #nimal fats including tallow, lard, yellow grease and as a yproduct fromthe production of mega/D fatty acids from "sh oil.

Worldwide production of &egetale oil and animal fat is not yet su*cient toreplace liuid fossil fuel use. 0urthermore, some en&ironmental groups (notalythe 9atural $esources 1efense +ouncil), o8ect to the &ast amount of farming andthe resulting o&er/fertili!ation, pesticide use, and land use con&ersion that woulde needed to produce the additional &egetale oil.

any ad&ocates suggest that waste &egetale oil is the est source of oil toproduce iodiesel. owe&er, the a&ailale supply is drastically less than theamount of petroleum/ased fuel that is urned for transportation and homeheating in the world. #ccording to the 7nited States 6n&ironmental 5rotection#gency (65#), restaurants in the 7S produce aout DHH million 7S gallons(,HHH,HHH m) of waste cooking oil annually. #lthough it is economically

pro"tale to use WV to produce iodiesel, it is e&en more pro"tale to con&ertWV into other products such as soap. ence, most WV that is not dumped intoland"lls is used for these other purposes. #nimal fats are similarly limited insupply, and it would not e e*cient to raise animals simply for their fat.owe&er, producing iodiesel with animal fat that would ha&e otherwise eendiscarded could replace a small percentage of petroleum diesel usage.

The estimated transportation fuel and home heating oil use in the 7nited Statesis aout GDH,HHH million 7S gallons (H.?F km) (


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0or a truly renewale source of oil, crops or other similar culti&atale sourceswould ha&e to e considered. 5lants utili!e photosynthesis to con&ert solarenergy into chemical energy. 't is this chemical energy that iodiesel stores and isreleased when it is urned. Therefore plants can o-er a sustainale oil source foriodiesel production. 1i-erent plants produce usale oil at di-erent rates. Somestudies ha&e shown the following annual production:

• Soyean: CH to @H 7S galIacre (CH to @H mIkm_)

• $apeseed: H to C@ 7S galIacre (HH to CH mIkm_)

• ustard: CH 7S galIacre (DH mIkm_)

• Ratropha: F@ 7S galIacre (AH mIkm_)

• 5alm oil: A@H 7S galIacre (AH mIkm_)• #lgae: H,HHH to GH,HHH 7S galIacre (H,HHH to GH,HHH mIkm_)

There is ongoing research into "nding more suitale crops and impro&ing oilyield. 7sing the current yields, &ast amounts of land and fresh water would eneeded to produce enough oil to completely replace fossil fuel usage.

Soyeans are not a &ery e*cient crop solely for the production of iodiesel, uttheir common use in the 7nited States for food products has led to soyeaniodiesel ecoming the primary source for iodiesel in that country. Soyeanproducers ha&e loied to increase awareness of soyean iodiesel, expandingthe market for their product.

'n 6urope, rapeseed is the most common ase oil used in iodiesel production. 'n'ndia and southeast #sia, the Ratropha tree is used as a signi"cant fuel source,and it is also planted for watershed protection and other en&ironmentalrestoration e-orts. alaysia and 'ndonesia are starting pilot/scale productionfrom palm oil.

Specially red mustard &arieties can produce reasonaly high oil yields, and ha&ethe added ene"t that the meal lefto&er after the oil has een pressed out canact as a e-ecti&e and iodegradale pesticide.

The production of algae to har&est oil for iodiesel has not een undertaken on acommercial scale, ut working feasiility studies ha&e een conducted to arri&eat the ao&e yield estimate. 'n addition to a high yield, this solution does notcompete with agriculture for food, reuiring neither farmland nor fresh water.

3.2. '


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#dditional factors must e taken into account, such as: the fuel eui&alent of theenergy reuired for processing, the yield of fuel from raw oil, the return onculti&ating food, and the relati&e cost of iodiesel &ersus petrodiesel. # BB? 8ointstudy y the 7.S. 1epartment of 6nergy (16) and the 7.S. 1epartment of #griculture (7S1#) traced many of the &arious costs in&ol&ed in the production of iodiesel and found that o&erall, it yields D.G units of fuel product energy fore&ery unit of fossil fuel energy consumed. That measure is referred to as theenergy yield. # comparison to petroleum diesel, petroleum gasoline andioethanol using the 7S1# numers can e found at the innesota 1epartmentof #griculture wesite. 'n the comparison petroleum diesel fuel is found to ha&e aH.?CD energy yield, along with H.?H@ for petroleum gasoline, and .DC forioethanol. The BB? study used soyean oil primarily as the ase oil to calculatethe energy yields. 't is concei&ale that higher oil yielding crops could increasethe energy yield of iodiesel. The deate o&er the energy alance of iodiesel isongoing, howe&er.

Some nations and regions that ha&e pondered transitioning fully to iofuels ha&e

found that doing so would reuire immense tracts of land if traditional crops areused. +onsidering only traditional plants and analy!ing the amount of iodieselthat can e produced per unit area of culti&ated land, some ha&e concluded thatit is likely that the 7nited States, with one of the highest per capita energydemands of any country, does not ha&e enough arale land to fuel all of thenation=s &ehicles. ther de&eloped and de&eloping nations may e in ettersituations, although many regions cannot a-ord to di&ert land away from foodproduction. 0or third world countries, iodiesel sources that use marginal landcould make more sense, e.g. honge nuts grown along roads.

ore recent studies using a species of algae that has oil contents of as high as@H ha&e concluded that as little as G?,HHH km_ or H.D of the land area of the

7S could e utili!ed to produce enough iodiesel to replace all transportation fuelthe country currently utili!es. 0urther encouragement comes from the fact thatthe land that could e most e-ecti&e in growing the algae is desert land with highsolar irradiation, ut lower economic &alue for other uses and that the algaecould utili!e farm waste and excess +G from factories to help speed the growthof the algae.

The direct source of the energy content of iodiesel is solar energy captured yplants during photosynthesis. The wesite www.iodiesel.co.uk discusses thepositi&e energy alance of iodiesel:

When straw was left in the eld, biodiesel production was strongly energy

positive, yielding 1 GJ biodiesel for every 0.561 GJ of energy input a yield!cost ratio of 1."#$.When straw was burned as fuel and oilseed rape%eal was used as afertili&er, the yield!cost ratio for biodiesel production was even better '."1$. (n other words, for every unit of energy input to produce biodiesel,the output was '."1 units the di)erence of *."1 units would be fro% solar energy$.


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-lco+ol fuel

The use of alcohol as a fuel for internal comustion engines, either alone or incomination with other fuels, has een gi&en much attention mostly ecause of its possile en&ironmental and long/term economical ad&antages o&er fossil fuel.


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%.#.Politics

&. 8.S. =ational security

1. -lco+ol uels

5roposals to use alcohol as a fuel are generally concerned with its use intransportation, chieKy as a total or partial replacement for gasoline in cars andother road &ehicles. owe&er, other less con&entional approaches ha&e eenad&anced, such as the use of alcohol in fuel cells, either directly or as a feedstockfor hydrogen production. To ha&e a net energy gain, it is critical that detailedenergy and input stock analyses e performed. +urrently, all studies indicate anet energy loss in the production of #lcohol 0uel &ersus eui&alent oil products.

This is due to the use of petrochemicals for pesticides, fertili!ers, and operationof farm and other machinery in the processing of the feed stock. Without a netenergy gain, reduction in the use of il etc. does not occur

0uel alcohols can e produced from a &ariety of crops, such as hemp, kenaf,sugarcane, sugar eets, mai!e, arley, potatoes, cassa&a, sunKower, eucalyptus,etc. Two countries ha&e de&eloped signi"cant io/alcohol programs:


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iomass, the comustion of ethanol produces no net caron dioxide. When fullycomusted, its comustion products are only caron dioxide and water which arealso the y/products of regular cellulose waste decomposition. 0or this reason, itis fa&oured for en&ironmentally conscious transport schemes and has een usedto fuel pulic uses. owe&er, pure ethanol reacts with or dissol&es certainruer and plastic materials and cannot e used in unmodi"ed engines.#dditionally, ethanol has a much higher octane rating (aout @) than ordinarygasoline, reuiring changes to the compression ratio or spark timing to otainmaximum ene"t. To change a gasoline/fueled car into an pure/ethanol/fueledcar, larger caruretor 8ets (aout DH/CH larger y area) are needed. (ethanolreuires an e&en larger increase in area, to roughly @H larger.) # cold startingsystem is also needed to ensure su*cient &apori!ation for temperatures elow@ J+ (@B J0) to maximi!e comustion and minimi!e uncomusted non&apori!edethanol. 'f H to DH ethanol is mixed with gasoline, no engine modi"cation istypically needed. any modern cars can run on the mixture &ery relialy.

# mixture containing gasoline with approximately H ethanol is known as

gasohol. 't was introduced nationwide in 1enmark, and in B?B,


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possily leading to neural damage. owe&er this was a minor source of lead sincetetraethyl lead was used as a gasoline additi&e. Today, ethanol for fuel use isproduced almost exclusi&ely from purpose uilt plants eliminating any use of lead.'n


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expensi&e to e used generously enough to e as e-ecti&e as they were meantto e.

#lternati&ely, an electric heater (for home con&ersion, an glow plug from an olddiesel engine) would ser&e to preheat the con&erter a it more rapidly than anengine y itself would y idling for @ or H minutes. The catalytic con&erter wouldstill e operating elow the reuired temperature for some time, ut less than inan unmodi"ed &ehicle, thus cutting pollution le&els signi"cantly. 9ote that hyrid&ehicles will e easier to modify this way ecause they already ha&e atterysystems that can supply su*cient power to heat the catalyst su*ciently,whereas con&entional cars may need electrical modi"cations to enale this.

#n additional prolem of methanol is that its energy content is only C@ that of gasoline (F@ of ethanol).

9e&ertheless, a dri&e to add a signi"cant percentage of methanol to gasoline got&ery close to implementation in


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ne ad&antage shared y all four alcohols is octane rating.


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and the processing of cassa&a was consideraly more complex, as it wouldreuire cooking the root to turn the starch into fermentale sugar. The aauplant was also in&estigated as a possile source of alcohol.

There is also growing interest in the use of waste iomass as a source for alcoholother types of fuel. 9ew technologies such as cellulose to ethanol productioncould pro&ide much higher positi&e energy ratios of G to D times more energy inethanol produced than input. +ellulose to ethanol production could also run onany cellulose source from farm waste, hayIgrass, asically any plant matterincluding wood, cardoard and paper. Theoretically farms could produce fuelwithout sacri"cing food production, ecause all that is needed is the left o&erplant matter after har&esting. +ellulose to ethanol production is still inde&elopment and has seen limited use in industrial ethanol production. Theiggest challenges in using cellulose as a feedstock is the treatment and disposalof process waste and the con&ersion of +@ sugars (these are typicallyuncon&erted adding to the waste treatment demand). 7nlike grain asedprocesses which produce a y/product known as distillers grain with minimal

waste treatment needs, cellulosic processes are typically euent and wastetreatment intensi&e. 1istiller grain is a protein enriched animal feed with muchhigher nutritional &alue than natural grain and is typically priced at less than half that of natural grain. 't therefore tends to e a desirale product for animalfeeders. #pproximately one/third of grain usage in the production of ethanol inmodern plants is reco&ered as distillers grain.

#t this time, most of the di-erent processes for con&erting iomass into ethanoland other fuels are &ery complicated and not particularly e*cient. # fewprocesses ha&e seen increasing u!!, including thermal depolymeri!ation(though that process produces what is descried as light crude oil).

't is possile to decompose cellulose into sugar in strong or weak solutions of sulphuric acid, ut this process also decomposes and wastes perhaps half thepotential sugar content and creates large amounts of acidic waste, so scientistsare searching for more e*cient and less polluting en!ymatic and microialprocesses for reaking down cellulose into sugar.

#nother approach under de&elopment is to gasify iomass y heating it in anoxygen/poor en&ironment. This yields hydrogen, methane and caron monoxideas well as noncomustile caron dioxide and nitrogen compounds.


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. =et fuel ener"y alance

To e &iale, an alcohol/ased fuel economy should ha&e positi&e net fuel energyalance. 9amely, the total fuel energy expended in producing the alcohol Lincluding fertili!ing, farming, har&esting, transport, fermentation, distillation, anddistriution, as well as the fuel used in uilding the farm and fuel planteuipment L should not exceed the energy contents of the product.

This is a contro&ersial su8ect charged with potential ias. uch of it depends onwhat is included and what is excluded from the calculation, particularly whencompared with the energy alance of the production of gasoline itself. #nalysesare greatly complicated y &arious methods of accounting for the energy &aluecoproducts and consideration of alternate uses of the feedstock. 9ot surprisingly,this deate has een at est inconclusi&e to date.

Switching to a system with negati&e fuel energy alance would only increase theconsumption of non/alcohol fuels. Such a system would only e worth considering

as a way of exploiting non/alcohol fuels that may not e suitale fortransportation use, such as coal, natural gas, or iofuel from crop residues.('ndeed, many 7.S. proposals assume the use of natural gas for distillation.)owe&er, many of the expected en&ironmental and sustainaility ad&antages of alcohol fuels would not e reali!ed in a system with negati&e fuel alance.

6&en a positi&e ut small energy alance would e prolematic: if the net fuelenergy alance is @H, then, in order to eliminate the use of non/alcohol fuels, itwould e necessary to produce two units of alcohol for each unit of alcoholdeli&ered to the consumer.

'n this regard, geography is the decisi&e factor. 'n tropical regions with aundant

water and land resources, such as


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replacing gasoline powered euipment with more fuel/e*cient diesel engines. Total farm energy use peaked in BF? at G,GCC trillion


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gasoline or diesel fuel, there was a gain of A.DC units of energy. S7 6thanol6nergy


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6thanol appears to e less of a "re ha!ard than gasoline; while methanol, eingmore &olatile, is somewhat more prone to "re and explosions. owe&er, sinceethanol and methanol dissol&e in water (rather than Koating on it like gasoline)their "res can e extinguished with ordinary water hoses.ne of the prolems with accidental comustion of pure ethanol is that it urnswith a dim, lue Kame, with in&isile smoke. ethanol Kames are dim enough toe considered in&isile in daylight.


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of 1ecatur, 'llinois, etter known as #1, the world=s largest grain processor,produces CH of the ethanol used to make gasohol in the 7.S. The company andits o*cers ha&e een elouent in their defense of ethanol and generous incontriuting to oth political parties.

Tax 'ncenti&es for ethanol and petroleum: 7.S. 2eneral #ccounting *ce,Septemer GHHH. This study examines susidies historically gi&en to the oilindustry and to the ethanol industry and "nds that the amounts of those to the oilindustry are far higher. #t the same time, this study applies only to historicalsusidies and doesn=t in&estigate the uestion of what the case would e if petroleum fuels were sustantially replaced y ethanol.

#.#. Cost

Some economists ha&e argued that using ioalcohol as a petroleum sustitute iseconomically infeasile ecause the energy reuired to grow the corn and othercrops used as fuel is greater than the amount ultimately produced. They argue

that go&ernment programs that mandate the use of ioalcohol are simplyagricultural susidies enacted to gain &otes from hea&ily agricultural states,especially 'owa. owe&er, this reKects a lack of understanding of the motor fuelindustry; production of gasoline also reuires more energy input than the fuelitself pro&ides, ut the trade/o- is worthwhile ecause it con&erts less portaleforms of energy (electricity for pumps, urning o- crude oil for heat at re"neries,etc.) into a high/&alue (portale, easily used) form of energy. #s of GHH@, ethanolproduction has actually ecome much more energy/e*cient than gasolineproduction, with energy inputs as low as FH of the energy &alue of the ethanolproduced.

%. -lco+ol fuel in 7razil

#n early poster promoting alcohol fuel warns


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throughout the country; they are typically owned and run y ig farms or farmconsortia and located near the producing "elds. #t the mill the cane is roller/pressed to extract the 8uice (garapa), lea&ing ehind a "rous residue (agasse).

The 8uice is fermented y yeasts which reak down the sucrose into +G andethanol. The resulting %wine% is distilled, yielding hydrated ethanol (@ water y&olume) and %fusel oil%. The acidic residue of the distillation (&inhoto) isneutrali!ed with lime and sold as fertili!er. The hydrated ethanol may e sold asis (for ethanol cars) or e dehydrated and used as a gasoline additi&e (forgasohol cars). 'n either case, the ulk product was sold until BBA at regulatedprices to the state oil company (5etroras). Today it is no longer regulated.

ne ton (,HHH kg) of har&ested sugarcane, as shipped to the processing plant,contains aout C@ kg of dry "er (agasse) and D? kg of sucrose. f that, Gkg can e extracted as sugar, lea&ing GD kg in low/&alued molasses. 'f the cane isprocessed for alcohol, all the sucrose is used, yielding FG liters of ethanol.


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report, the World ank would only "nance in&estments in agasse powergeneration if the price were at least 7SYBI2R.)


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5resently the use of ethanol as fuel y


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The


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•


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-P6 "ravity

#5' 2ra&ity is a speci"c gra&ity scale de&eloped y the #merican 5etroleum'nstitute (#5') for measuring the relati&e density of &arious petroleum liuids. #5'gra&ity is gradated in degrees on a hydrometer instrument and was designed so

that most &alues would fall etween H and FH #5' gra&ity degrees.

The 7.S. 9ational

wikipedia - presentation of an oil refinery.doc

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