Chemical fuels

Definition, Types of fuels, primary, secondary, solid, liquid and gaseous fuels advantages and disadvantages, Coal - Proximate analysis and Ultimate analysis, Petroleum - Fractional distillation, petrol, diesel, composition, Cracking, Moving bed catalytic cracking, Knocking, octane number, cetane number, LPG, CNG

1. MATRUSRI ENGINEERING COLLEGE
DEPARTMENT OF SCIENCES AND HUMANITIES
SUBJECT NAME: CHEMISTRY
FACULTY NAME: VISHNU THUMMA
MATRUSRI
ENGINEERING COLLEGE
TOPIC: CHEMICAL FUELS

2. CHEMISTRY
2
COURSEOBJECTIVES:
➢Correlatethepropertiesofmaterialswiththeirinternalstructureandusethefor
Engineeringapplications
➢Applytheprinciplesofelectrochemistryinstorageofelectricalenergyin
batteries.
➢Gainsknowledgeincausesofcorrosionanditsprevention.
➢Attainsknowledgeaboutthedisadvantagesofhardwaterfordomesticand
industrialpurposes.
➢Alsolearnsthetechniquesofsofteningofhardwaterandtreatmentofwaterfor
drinkingpurpose.
➢Exposedtoqualitativeandquantitativeparametersofchemicalfuels.
➢Awareeco-friendlymaterialsandprocesses.
MATRUSRI
ENGINEERING COLLEGE

3. CHEMISTRY
3
COURSEOUTCOMES:Aftercompletionofcoursestudentswillbeableto
➢Analyzeandapplyknowledgeofelectrodicsincalculationofcellpotentials
ofbatteries.
➢Identifythedifferenttypesofhardnessandalkalinitiesinwaterandmake
useofsofteningmethods,analyzeandapplytheknowledgeofcorrosionfor
itsprevention.
➢Discussdifferenttypesofpolymersbasedontheirendonuseandthe
needtoreplacetheconventionalpolymerswithpolymersofengineering
applications.
➢Identifyandanalyzedifferenttypesofchemicalfuelsfordomesticand
automobileapplications.
➢Outlinetheprinciplesofgreenchemistryforsustainableenvironmentand
preparationofbiodieselfromrenewablesources.
MATRUSRI
ENGINEERING COLLEGE

4. UNIT-IV CHEMICAL FUELS
4
COURSEOUTCOMES:Aftercompletionofcoursestudentswillbeableto
Identifyandanalyzedifferenttypesofchemicalfuelsfordomesticand
automobileapplications.
MATRUSRI
ENGINEERING COLLEGE

5. Definition:Achemicalfuelisasubstancewhichoncombustioninairor
oxygenproducessignificantamountsofheatwhichcanbeused
economicallyfordomesticandindustrialpurposes.
5
Example:
Wood,
Coal,
Crude Oil,
Natural Gas, Etc.
MATRUSRI
ENGINEERING COLLEGE
MODULE-1: INTRODUCTION TO CHEMICAL
FUELS

6. Classification of Fuels
Chemicalfuelsarebroadlyclassifiedassolid,liquidandgaseousbased
ontheirphysicalstateinwhichtheyareused.
Thesearefurtherclassifiedasprimaryandsecondaryfuels.
Afuelthatoccursinnatureiscalleda“primaryfuel”
Whileallothers,whicharederivedfromprimaryfuelsarecalled
“secondaryfuels”.
6
MATRUSRI
ENGINEERING COLLEGE

7. Classification of Fuels
7
Physical
state
Primary fuels (Natural)
Secondary fuels
(Derived)
SolidWood, Coal, Lignite,
Bituminous, Anthracite, Peat
Charcoal,Coke
LiquidPetroleum(Crudeoil) Gasoline, Diesel,
Kerosene, Synthetic
petrol
GaseousNaturalgas Producer gas, Water
gas, Coal gas, LPG,
Biogas
MATRUSRI
ENGINEERING COLLEGE

8. Solid Fuels
8
Wood Coal Lignite
Bituminous
Anthracite
Peat
MATRUSRI
ENGINEERING COLLEGE

9. Liquid Fuels
9
MATRUSRI
ENGINEERING COLLEGE

10. High Calorific Value
Thecalorificvalueofafuelisthedirectmeasureofitsefficiencyasa
fuel.
Higherthecalorificvalue,moreefficientisthefuel.
Agoodfueltherefore,musthaveahighcalorificvalue.
10
MATRUSRI
ENGINEERING COLLEGERequirements of a Good Fuel

11. Moderate Ignition Temperature
Ignitiontemperatureistheminimumtemperaturetowhichthefuelisto
beheatedtostartcombustion.
Thefuelshavingverylowignitiontemperaturecancausefirehazards
duringtheirhandling,applications,storageandtransportation.
Itisratherdifficulttoignitefuelifitsignitiontemperatureistoohigh.
Hence,moderateignitiontemperatureisthemostdesiredpropertyofa
fuel
11
MATRUSRI
ENGINEERING COLLEGERequirements of a Good Fuel

12. Low Ash Content
Formationofashduringcombustionisduetothepresenceof
inorganicmatterinthefuel.
Highashcontentlowersthecalorificvalueandposesproblemsinits
disposal.
Agoodfuelmusttherefore,befreefromashcontent.
12
MATRUSRI
ENGINEERING COLLEGERequirements of a Good Fuel

13. Low Moisture Content
Thepresenceofhighpercentageofmoistureinfueldecreasesits
efficiency.
Italsoincreasestheignitiontemperatureandfuelcost.
Further,itlowersthecalorificvaluesincesomeoftheheatproducedis
utilizedtovaporizethemoisture.
Hence,fuelshouldhavelowmoisturecontent.
13
MATRUSRI
ENGINEERING COLLEGERequirements of a Good Fuel

14. No Harmful Combustion Products
Agoodfuelmustnotproduceharmfulcombustionproductssuchas
CO,SO
2,NO,H
2S,smokeandclinkersduringcombustion.
Formationofsuchby-productscancauseharmfuleffectsonhealth.
Agoodfuelmustthereforeburnwithcleanflamewithoutproducing
undesiredby-products.
14
MATRUSRI
ENGINEERING COLLEGERequirements of a Good Fuel

15. Combustioncontrol:Onecanavoidalargewastageofvaluablefuelif
itscombustionratecanbeproperlyregulatedandburningcanbe
stoppedimmediatelyasandwhendesired.
Easeofavailability:Fuelmustbereadilyavailableinabundant
amountanditscostmustbeminimum.
Easeofstorageandtransport:Fuelsshouldnotdemandmorespace
andsophisticatedarrangementsfortheirstorageandtransportation.
Furthertheremustbeminimumrisksoffirehazards.
15
MATRUSRI
ENGINEERING COLLEGERequirements of a Good Fuel

16. Solid Fuels -Advantages
➢Easy to transport.
➢Convenient to store without any risk of spontaneous explosion.
➢Cost of production is low.
➢Possess moderate ignition temperatures.
16
MATRUSRI
ENGINEERING COLLEGE

17. Solid Fuels -Disadvantages
➢Ash content is high.
➢Heat is wasted during combustion (low thermal efficiency.
➢Clinker formation.
➢Combustion operations cannot be controlled easily.
➢Cost of handling is high.
➢Low calorific value.
➢Excess of air for complete combustion.
➢Cannot be used as internal combustion engine fuels.
17
MATRUSRI
ENGINEERING COLLEGE

18. Liquid fuels -Advantages
➢Higher calorific value per unit mass than solid fuels.
➢Burn without forming dust, ash, clinkers, etc.
➢The firing is easier and also fire can be extinguished easily by stopping
the liquid fuel supply.
➢Easy to transport through pipes, and one man can easily regulate a
large number of furnaces simultaneously.
➢They can be stored indefinitely without any loss.
➢The flame produced by burning liquid fuels can easily be controlled by
adjusting the liquid fuel supply.
18
MATRUSRI
ENGINEERING COLLEGE

19. Liquid fuels -Advantages
➢Clean in use and economic in labour, Loss of heat to chimney is very
low due to greater cleanliness.
➢Less excess of air for complete combustion, Less furnace space for
combustion.
➢No wear and tear of grate bars and cleaning of fires etc. unlike solid
fuels.
➢They can be used as internal combustion fuels
19
MATRUSRI
ENGINEERING COLLEGE

20. Liquid fuels -Disadvantages
➢Thecostofliquidfuelisrelativelymuchhigherascomparedtosolid
fuels.
➢Costlyspecialstoragetanksarerequiredforstoringliquidfuels.
➢Thereisagreaterriskoffirehazards,particularlyincaseofahighly
inflammableandvolatileliquidfuel.
➢Theygivebadodour.
➢Forefficientburningofliquidfuels,speciallyconstructedburnersand
sprayingapparatusarerequired.
➢Chokingofsprayersisadrawbackofoilfiring.
20
MATRUSRI
ENGINEERING COLLEGE

21. Gaseous fuels -Advantages
➢Conveyedeasilythroughpipelinestotheactualplaceofneed,
therebyeliminatingmanuallabourintransportation.
➢Lightedatmoment’snotice,.
➢Haveheatcontentandhence,helpusinhavinghighertemperatures.
➢Theyhavehighcalorificvalue
➢Pre-heatedbytheheatofhotwastegases,therebyaffording
economyinheat.
➢Combustioncanreadilybecontrolledforchangesindemandlike
oxidizingorreducingatmosphere,lengthofflame,temperature,etc.
➢Burnwithoutanysootandareashless,sothereisnolabourinvolved
inashhandlingetc.
21
MATRUSRI
ENGINEERING COLLEGE

22. ➢Cleaninuse,donotrequireanyspecialburners,Complete
combustionwithoutpollutionispossible,duetouniformmixingofair
andfuel.
➢Burnwithoutheatloss,duetoconvectioncurrents,inslightexcessof
airsupply.
➢Freefromsolidandliquidimpurities.Hence,theydonotaffectthe
qualityofmetalproduced,whenusedasametallurgicalfuel.
➢Theycanalsobeusedasinternalcombustionfuels.
22
MATRUSRI
ENGINEERING COLLEGE
Gaseous fuels -Advantages

23. Gaseous fuels -Disadvantages
➢Verylargestorageranksareneededforthem.
➢Theyarehighlyinflammable,sochancesoffirehazardsarehighin
theiruse.
➢Theyaremorecostlyascomparedtosolidandliquidfuels.
23
MATRUSRI
ENGINEERING COLLEGE

24. 24
1. Which of the following is a primary fuel
a)Charcoal b) Coke
c) Wood d)None
2.The lowest Temperature at which the Fuel must be pre-heated so that it burns smoothly is
called
a)Critical Temperature b) Flame Temperature
c) Ignition Temperature d) Boiling point of fuel
3. One of the following isnot the quality of a good fuel
a) High calorific Value b) Moderate Ignition Temperature
c) Low moisture content d) Analysis of Flue gases
4.In which type of fuel given below, risk of fire hazard is greatest?
a) Solid fuel b) Liquid fuel
c) Gaseous fuel d) Natural gas
MATRUSRI
ENGINEERING COLLEGE
QUIZ

25. Itistheamountofheatreleasedwhenaunitmassorvolumeofafuelis
burntcompletelyinairoroxygen.
UnitsofHeat:
(1)'Calorie'istheamountofheatrequiredtoraisethetemperatureof
onegramofwaterthroughonedegreeCentigrade.
(1)"Kilocalorie"isequalto1,000calories.Itmaybedefinedas'the
quantityofheatrequiredtoraisethetemperatureofonekilogramof
waterthroughonedegreeCentigrade.
Thus:1kcal=1,000cal
(3)"BritishThermalunit"(B.T.U.)isdefinedas"thequantityofheat
requiredtoraisethetemperatureofonepoundofwaterthroughone
degreeFahrenheit.ThisistheEnglishsystemunit.
1B.T.U.=252cal=0.252kcal1kcal=3.968B.T.U.
25
MODULE-2: CALORIFIC VALUE
MATRUSRI
ENGINEERING COLLEGE

26. Higher Calorific Value (HCV) or Gross Calorific Value (GCV)
Itisdefinedastheamountofheatreleasedwhenunitquantityofafuel
isburntcompletelyinairandthecombustionproductsarecooledto
roomtemperature.
26
MATRUSRI
ENGINEERING COLLEGE

27. Itisdefinedastheamountofheatreleasedwhenaunitquantityofafuel
isburntcompletelyinair,andtheproductsofcombustionareletoff
intotheatmosphere.
LCV=HCV–latentheatofsteam
=HCV– x587cal/g
Because 1 g hydrogen gives 9 g of water and the latent heat of steam is
587 cal/g.
27
LowerCalorific Value (LCV) or Net Calorific Value (NCV)
MATRUSRI
ENGINEERING COLLEGE

28. 28
Theoretical Calculation of Calorific Value
TheHCVoffuelisthesumofcalorificvaluesofalltheconstituents
presentinfuel.
ConstituentHydrogenCarbonSulphur
HCV
(kcal/kg)
34500 8080 2240
Calorific values of fuel constituents
Dulong’sformulafor calorific value from the chemical composition of fuel
where, C,H,O and S are the percentage of carbon, hydrogen, oxygen and
sulphurin the fuel respectively.
In this formula, oxygen is assumed to be present in combination with
hydrogen as water
Kcal/kg
MATRUSRI
ENGINEERING COLLEGE

29. 29
LCV = HCV –0.09H x 587 kcal/kg
Since,1partofHbymassgives9partsofH
2Oandlatentheatofsteam
is587kcal/kg.
MATRUSRI
ENGINEERING COLLEGE

30. 30
Numerical Problem:
Calculate the gross and net calorific value of a coal sample having the following
composition; C=80%, H=7%, O=3%, S=3.5%, N=2.1% and ash=4%.
Kcal/kg
= 8828 kcal/kg
LCV = HCV –0.09H x 587
= 8828 –0.09 x 7 x 587 = 8458 kcal/kg
MATRUSRI
ENGINEERING COLLEGE

31. 31
MATRUSRI
ENGINEERING COLLEGEQUIZ
1.Which of the following factor does not affect the gross calorific value?
a) CO
2
emissions from the fuel b) Latent heat produced in the fuel
c) Size of the fuel d) Moisture content of the fuel
2.HCVandLCVarerelatedby
a)HCV=LCV-0.09*587cal/g b)HCV=LCV-0.9*587Cal/g
c) HCV= LCV-98* 587 cal/g d) Both A and B
3. Amount of energy released when unit mass of the fuel is burnt, and the products of
combustion are let off into the atmosphere is called
a) High calorific value b) Low calorific value
c)Net calorific value d) Both B&C
4. Calorific value of the fuel can be calculated by
a) By using Seyler’sformulae b) By using Dulong’sformula
c) By using Davies formulae d) By using Nakamura’s formulae

32. MODULE-3: Solid fuel -Coal
Coalisahighlycarbonaceousmatterthathasbeenformedasaresultof
alterationofvegetablematter(e.g.,plants)undercertainfavourable
conditions.
ItischieflycomposedofC,H,N,andO,besidesnon-combustible
inorganicmatter.
Classification of Coal:
Coals are classified on the basis of their rank.
Rankisdefinedasthedegreeorextentofmaturationandisthereforea
qualitativemeasureofcarboncontents.
Peat,ligniteandsub-bituminouscoalsarereferredaslowrankcoals
whilebituminouscoalsandanthracitesareclassedashighrank.
32
MATRUSRI
ENGINEERING COLLEGE

33. COAL RANKING
33
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ENGINEERING COLLEGE
Wood
Peat
Lignite
Bituminous
Anthracite

34. Analysis of Coal
Inordertoassessthequalityofcoalthefollowingtwotypesofanalysis
aremade.
1.ProximateAnalysis:Itincludesthedeterminationofmoisture,
volatilematter,ashandfixedcarbon.
Thisgivesquickandvaluableinformationregardingcommercial
classificationanddeterminationofsuitabilityforaparticularindustrial
use.
2.UltimateAnalysis:Itincludesthedeterminationofcarbon,hydrogen,
nitrogen,sulphur,ashandoxygenincoal.
Sinceitisusedforthedeterminationofelementspresentinthecoal,itis
alsocalledelementalanalysis.
Thisanalysisgivesexactresultsandareusefulincalculatingthe
calorificvalueofcoalusingDulong'sformula.
MATRUSRI
ENGINEERING COLLEGE

35. 35
Moisture:About1goffinelypoweredair-driedcoal
sampleisweighedinacrucible.
Thecrucibleisplacedinsideanelectrichotair-oven,
maintainedat105°-110°C.
Thecrucibleisallowedtoremaininovenfor1hourand
thentakenout,cooledinadesiccatorandweighed.
Lossinweightisreportedasmoisture(onpercentage-
basis).
Proximate Analysis
MATRUSRI
ENGINEERING COLLEGE

36. 36
Moisturelowerstheeffectivecalorificvalueofcoal.
Itquenchesthefireinthefurnace.
Hence,lesserthemoisturecontent,betterthequalityofcoalasafuel.
However,presenceofmoisture,upto10%,producesamoreuniform
fuel-bedandlessof"fly-ash".
Significance of Moisture:
MATRUSRI
ENGINEERING COLLEGEProximate Analysis

37. 37
Volatilematter:Thedriedsampleofcoalleftinthe
crucibleisthencoveredwithalidandplacedinan
electricfurnace(mufflefurnace),maintainedat
925°±20°C.
Thecrucibleistakenoutoftheovenafter7minutesof
heating.
Thecrucibleiscooledfirstinair,theninsidea
desiccatorandweighedagain.
Lossinweightisreportedasvolatilematteron
percentage-basis.
MATRUSRI
ENGINEERING COLLEGEProximate Analysis

38. 38
Highvolatilemattercontentmeansthatahighproportionoffuelwilldistill
overasgasorvapours,alargeproportionofwhichescapesun-burnt.
So,highervolatilecontentincoalisundesirable.
Ahighvolatilemattercontainingcoalburnswithalongflame,high
smokeandhaslowcalorificvalue.
Hence,lesserthevolatilematter,bettertherankofcoal.
Significance of Volatile Matter:
MATRUSRI
ENGINEERING COLLEGEProximate Analysis

39. 39
Ash:Theresidualcoalinthecrucibleisthenheated
withoutlidinamufflefurnaceat700
0
Cfor½hour.
Thecrucibleistakenoutcooledfirstinair,thenin
desiccatorsandweighed.
Heating,coolingandweighingisrepeatedtillaconstant
weightisobtained.
Theresidueisreportedasashonpercentagebasis.
MATRUSRI
ENGINEERING COLLEGEProximate Analysis

40. 40
Itisauseless,non-combustiblematter,whichreducesthecalorificvalue
ofcoal.
Itcausesthehindrancetotheflowofairandheat,therebyloweringthe
temperature.
Itoftencausestroubleduringfiringbyformingclinkerswhichblockthe
interspacesofthegrateonwhichcoalisbeingburnt.
Thisin-turncausesobstructiontoairsupply,therebytheburningofcoal
becomeirregular.
Hence,lowertheashcontentbetteristhequalityofcoal.
Significance of Ash:
MATRUSRI
ENGINEERING COLLEGEProximate Analysis

41. 41
Fixed carbon:
Percentage of fixed carbon = 100 -% of (moisture + volatile matter + ash)
Higherthepercentageoffixedcarbongreaterisitscalorificvalueandbetter
thequalityofcoal.
Significance:
MATRUSRI
ENGINEERING COLLEGEProximate Analysis

42. 42
MATRUSRI
ENGINEERING COLLEGEQUIZ
1. Which of the following form of coal has the highest amount of carbon
a) Peat b) Bituminous
c) Lignite d) Anthracite
2. Proximate analysis of the coal checks which one of the following characteristics
a)moisture content b) Ash
c) volatile impurities d) All the above
3. Why is the high percentage of moisture undesirable for coal?
a) It increases the rate of combustion b) It increases the cost of the coal
c) It reduces the calorific value of coal d) It decreases its ignition temperature
4.Which of the following is a noncombustible substance in coal?
a) volatile matter b) ash content
c) fixed carbon d) all the above

43. Carbonandhydrogen:About1-2gofaccuratelyweighedcoalsample
isburntinacurrentofoxygeninacombustionapparatus.
CandHofthecoalareconvertedintoCO
2andH
2Orespectively.
ThegaseousproductsofcombustionareabsorbedrespectivelyinKOH
andCaCl
2tubesofknownweights.
Theincreaseinweightsofthesearethendetermined.
43
MODULE-4: ULTIMATE ANALYSIS
MATRUSRI
ENGINEERING COLLEGE

44. 44
Combustion: C + O
2→CO
2 ↑
H
2+ ½ O
2→H
2O ↑
Flue gases:2KOH + CO
2→K
2CO
3+ H
2O (in KOH tube)
CaCl
2+ 7 H
2O →CaCl
2.7H
2O (in CaCl
2tube)
MATRUSRI
ENGINEERING COLLEGE
ULTIMATE ANALYSIS

45. 45
SignificanceofCarbonandHydrogen:
Greaterthepercentageofcarbonandhydrogenbetteristhecoalin
qualityandcalorificvalue.
However,hydrogenismostlyassociatedwiththevolatilematterand
hence,itaffectstheusetowhichthecoalisput.
Theamountofcarbon,themajorcombustibleconstituentofcoal,
dependsonthetypeofcoalanditspercentageincreaseswithrank
fromlignitetoanthracite.
Thus,percentageofcarbonformsthebasisofclassificationofcoal.
MATRUSRI
ENGINEERING COLLEGE
ULTIMATE ANALYSIS

46. Nitrogen:About1gofaccuratelyweighed
powderedcoalisheatedwith
concentratedH
2SO
4alongwithK
2SO
4
inalong-neckedflask.
Afterthesolutionbecomesclear,itistreated
withexcessofKOHandtheliberated
ammoniaisdistilledoverand
absorbedinaknownvolumeof
standardacidsolution.
Theunusedacidisthendeterminedbyback
titrationwithstandardNaOHsolution.
Fromthevolumeofacidusedbyammonia
liberated,thepercentageofnitrogenin
coaliscalculated.
46
MATRUSRI
ENGINEERING COLLEGE
ULTIMATE ANALYSIS

47. 47
Significance:Ithasnocalorificvalueandhenceitspresenceincoal
isundesirable.Thus,agoodqualitycoalshouldhaveverylittle
nitrogencontent.
MATRUSRI
ENGINEERING COLLEGE
ULTIMATE ANALYSIS

48. Sulphur:Itisdeterminedfromthewashings
obtainedfromtheknownmassofcoal,
usedinbomb calorimeterfor
determinationofcalorificvalue.
DuringthisdeterminationSisconvertedinto
sulphate.
ThewashingsaretreatedwithBaCl
2solution,
andthenBaSO
4isprecipitated.
Thisprecipitateisfiltered,washedandheated
toconstantweight.
48
MATRUSRI
ENGINEERING COLLEGE
ULTIMATE ANALYSIS

49. 49
Significance:Sulphuralthoughcontributestotheheatingvalueof
coal,yetoncombustionproducesacidswhichhaveharmfuleffectsof
corrodingtheequipmentandalsocauseatmosphericpollution.
Sulphurisusuallypresenttotheextentof0.5to3.0%andderived
fromoreslikepyrites,gypsumetc.minesalongwiththecoal.
MATRUSRI
ENGINEERING COLLEGE
ULTIMATE ANALYSIS

50. 50
Ash:Thedriedcoalistakeninacrucible.
Andheatedwithoutlidinamufflefurnaceat700
0
Cfor½
hour.
Thecrucibleistakenoutcooledfirstinair,thenin
desiccatorsandweighed.
Heating,coolingandweighingisrepeatedtillaconstant
weightisobtained.
Theresidueisreportedasashonpercentagebasis.
MATRUSRI
ENGINEERING COLLEGE
ULTIMATE ANALYSIS

51. 51
Itisauseless,non-combustiblematter,whichreducesthecalorificvalue
ofcoal.
Itcausesthehindrancetotheflowofairandheat,therebyloweringthe
temperature.
Itoftencausestroubleduringfiringbyformingclinkerswhichblockthe
interspacesofthegrateonwhichcoalisbeingburnt.
Thisin-turncausesobstructiontoairsupply,therebytheburningofcoal
becomeirregular.
Hence,lowertheashcontentbetteristhequalityofcoal.
Significance:
MATRUSRI
ENGINEERING COLLEGE
ULTIMATE ANALYSIS

52. Oxygen:%ofO=100-%of(C+H+S+N+Ash)
52
Significance:
Oxygencontentdecreasesthecalorificvalueofcoal.Highoxygen
contentcoalsarecharacterizedbyhighinherentmoisture,lowcalorific
valueandlowcokingpower.
Moreover,oxygenisincombinedformwithhydrogenincoalandthus,
hydrogenavailableforcombustionislesserthanactualone.
Anincreasein1%oxygencontentdecreasesthecalorificvalueby
about1.7%andhence,oxygenisundesirable.Thus,agoodqualitycoal
shouldhavelowpercentageofoxygen.
MATRUSRI
ENGINEERING COLLEGE
ULTIMATE ANALYSIS

53. QUIZ
1.Which of the following constituents are determined in ultimate analysis of coal?
a) C,H b) N,S
c) ash d) all
2. The Kiejald’smethod is used to determine
a) S b) N
c) O d) C
3. Which of the following constituent decreases the available hydrogen coal?
a) S b) N
c) O d) C
4. Washings of bomb calorimeter is used to determine
a) S b) N
c) O d) C
53
MATRUSRI
ENGINEERING COLLEGE

54. 54
➢Crudeoilcalledasblackgoldisadarkbrownorgreenishviscous
liquid.
➢Itisamixtureofseveralhydrocarbonsandformedinnatureover
hundredsofyearsobtainedfromremnantsofplants,animals,planktons,
bacteriaalongwithsoilgetdepositedonoceanbeds.
➢Asaresultofhighpressureandtemperaturetheydecomposetooil.
➢Petroleumoccursalongwithsaltwaterandnaturalgasbelowtherock
layers.
MODULE-5: LIQUID FUELS -PETROLEUM
MATRUSRI
ENGINEERING COLLEGE

55. Liquid Fuels -Petroleum
Ondrillingthroughametallicdrillerthedissolvednaturalgasescapes
intoairwhichispumpedoutbypipeline.
Afterthisthecrudeoilispumpedoutmechanicallywithcompressesair
pumpswhicharetransportedbyseparatepipelinesforfurtheruse.
55
Theaveragecomposition
ofcrudeoil:
C=80-87%,
H=11-15%,
S=0.1-3.5%,
(N+O)=0.1-0.5%.
MATRUSRI
ENGINEERING COLLEGE

56. 56
MATRUSRI
ENGINEERING COLLEGELiquid Fuels -Petroleum

57. 57
The largest reserves arefoundin the Western Offshore (Mumbai High, Krishna-Godavari Basin) (40%),
and Assam (27%).
MATRUSRI
ENGINEERING COLLEGE

58. 58
Theprocessiscalled"RefiningofPetroleum"andtherefiningplants
arecalled"Oilrefineries".
Theprocessofrefininginvolvesthefollowingsteps:
Thecrudeoilobtainedfromtheearth’scrustcontainsbrine,sulphur
andsomeunwantedimpurities.
Afterremovalofwater,sulphurandotherimpurities,thecrudeoilis
separatedintovarioususefulfractionsbyfractionaldistillationand
finallyconvertedintodesiredspecificproductshavingdifferent
boilingpoints.
Step-I:SeparationofWater
Step-II:RemovalofHarmfulImpurities
Step-III:FractionalDistillation
MATRUSRI
ENGINEERING COLLEGE
Liquid Fuels -Petroleum

59. 59
Step-I:Separationofwater(Cottrell'sprocess):
➢Thecrudeoilfromtheoilwellisanextremelystableemulsionofoil
andsaltwater.
➢Thecrudeoilisallowedtoflowbetweentwohighlycharged
electrodes,wherecolloidalwaterdropletscoalescetoformlarge
drops,whichisthenseparatedoutfromtheoil.
Step-II:Removalofharmfulimpurities:
➢ThepresenceofNaClandMgClinthecrudeoilcancorrodethe
refiningequipment,hencethesesaltsareremovedbyelectrical
desaltinganddehydrationmethods.
➢Thesulphurcompoundspresentinthecrudeoilisremovedbytreating
oilwithcopperoxide,whichresultsintheformationofcoppersulphide
(solid),whichisthenremovedbyfiltration.
MATRUSRI
ENGINEERING COLLEGE
Liquid Fuels -Petroleum

60. 60
Step-III:Fractionaldistillation:
➢Thecrudeoilisheatedtoabout400°Cinanironretort,wherebyall
volatilesubstances(exceptasphaltorcoke)areevaporated.
➢Thehotvaporspassupafractionatingcolumn,whichisatallcylindrical
towercontaininganumberofhorizontalstainlesssteeltraysatshort
distances.
➢Eachtrayisprovidedwithsmallchimneycoveredwithaloosecap.
➢Whenthevaporsoftheoilgoupinthefractionatingcolumn,they
becomegraduallycoolerandgetcondensedatdifferentheightsof
column.
➢Thefractionshavinghigherboilingpointscondenseatlowertrays
whereasthefractionshavinglowerboilingpointscondenseathigher
trays.
MATRUSRI
ENGINEERING COLLEGE
Liquid Fuels -Petroleum

61. 61
MATRUSRI
ENGINEERING COLLEGE

62. Composition and uses of various fractions obtained from Crude Oil
62
S.No Name of fraction Boiling rangeComposition Applications
1Uncondensedgas <30
0
C C
1toC
4
Asdomesticorindustrialfuel
underthenameLPG.
2Petroleumether 30
0
to70
0
C C
5toC
7
Asasolvent.
3GasolineorPetrolorMotorspirit.40
0
to120
0
CC
5toC
9
Asmotorfuel,solvent,indry
cleaning.
4NapthaofSolventspirit 120
0
to180
0
CC
9toC
10
Assolvent,drycleaning.
5Keroseneoil 180
0
to250
0
CC
10toC
16
Asjetenginefuel,toprepare
laboratorygas.
6Dieseloil 250
0
to320
0
CC
10toC
18
Asdieselenginefuel.
7Heavyoil 320
0
to400
0
CC
17toC
30
Forgettinggasolinebycracking.
8AsphaltorPetroleumcoke Above400
0
CC
30andaboveWaterproofing,roadmaking.
MATRUSRI
ENGINEERING COLLEGE

63. 63
Gasoline or Petrol
➢Itisamixtureofhydrocarbonsfrompentanetooctane.
➢Itisobtainedbetween40to120
0
C.
➢Itscalorificvalueis11,250kcal/kg.
➢Itishighlyvolatileandinflammable.
➢Itisusedasfuelforinternalcombustionengine.
MATRUSRI
ENGINEERING COLLEGE

64. 64
Diesel Oil
➢It is a mixture of higher hydrocarbons C
10to C
18.
➢It is obtained between 250 to 320
0
C.
➢Its calorific value is 11,000 kcal/kg.
➢It is used as a fuel for diesel engine.
MATRUSRI
ENGINEERING COLLEGE

65. 65
Kerosene Oil
➢It is a mixture of hydrocarbons C
10to C
16.
➢It is obtained between 180 to 250
0
C.
➢Its calorific value is 11,100 kcal/kg.
➢It does not vaporize easily due to its high boiling point.
➢It is used as domestic fuel in stoves, as jet engine fuel and
for making oil gas.
MATRUSRI
ENGINEERING COLLEGE

66. 66
MATRUSRI
ENGINEERING COLLEGE
1. Which type of process is used for the refining of petroleum?
a) Destructive distillation b) Zone distillation
c) Fractional distillation d) Steam distillation
2. Composition of gasoline or petrol is
a) C
10
-C
16
b) C
5
-C
9
c) C
10
-C
18
d) C
17
-C
32
3. Whichof the following fraction is used as jet fuel?
a) kerosene b) diesel
c) gasoline d) None
4.The uncondensed gases in fractional distillation method are used as
a) CNG b) LPG
b) Coal gas d) water gas
QUIZ

67. MODULE-6: CRACKING
Thedecompositionofbiggerhydrocarbonmoleculesintosimpler,low
boilinghydrocarbonsoflowermolecularweightiscalledcracking.
67
B.P.=174
0
C B.P.=36
0
C
C
10H
22→C
5H
12+ C
5H
10
Decane Pentane Pentene
MATRUSRI
ENGINEERING COLLEGE

68. 68
Crackingcanbeclassifiedintotwotypes:
1.ThermalCracking
2.CatalyticCracking
1.Inthermalcrackinglargehydrocarbonsbreakintosmalleronesathigh
temperatures(750°C)andpressure(70atmospheres).Thermalcrackinggives
mixturesofproductscontaininghighproportionsofhydrocarbonswithdouble
bonds-alkenes.
2.CatalyticCracking:
Thealkaneisbroughtintocontactwiththecatalystatatemperatureofabout
500°Candmoderatelylowpressures.Thezeolites(aluminosilicates)areusedin
catalyticcracking.Thiscatalystischosentogivehighpercentagesofhydrocarbons
withbetween5and10carbonatoms-particularlyusefulforpetrol(gasoline).
MATRUSRI
ENGINEERING COLLEGE

69. 69
Thezeolitecatalysthassiteswhichcanremoveahydrogenfroman
alkanetogetherwiththetwoelectronsleavingthecarbonatomwitha
positivecharge.
Reorganisationofthesecarboniumionsleadstothevariousproducts
probablyC
5-C
9inmajorproportions.
MATRUSRI
ENGINEERING COLLEGE

70. 70
❖Thegasolineobtainedfromthefractionaldistillationofpetroleum,has
thehighestdemandasamotorfuel,buttheyieldofthisfractionsis
only20-30%(Crudeoil).
❖Andalsoqualityasstraight-rungasolinewhichisnotgoodandhence
isusedonlyafterproperblending.
❖Toovercomethesedifficulties,thehigherboilingfractions(e.g.fueloil
andgasoil)areconvertedintolowerboilingfractionsgasoline(petrol)
bycrackingprocess.
❖Thecrackedgasolinegivesbetterengineperformancei.e.,theyare
suitableforsparkignitionenginesofautomobiles.
❖Incrackingprocess,highersaturatedhydrocarbonmoleculesare
convertedintosimplermoleculessuchasparaffinicandolefinic
hydrocarbons.
Significance of cracking
MATRUSRI
ENGINEERING COLLEGE

71. Thesolidcatalystisveryfinelypowdered,sothatitbehavesalmostasa
fluid,whichcanbecirculatedingasstream.
71
Moving-bed (Fluid-bed) Catalytic Cracking
MATRUSRI
ENGINEERING COLLEGE

72. 72
➢Thevapoursofcrackingstockmixedwithfluidizedcatalystisforcedup
intoalargereactor‘bed’inwhichcrackingoftheheavierintolighter
moleculesoccur.
➢Nearthetopofthereactorthereisacentrifugalseparatorcalled
cyclone,whichallowsonlythecrackedoilvapourstopassontothe
fractionatingcolumn,butretainsallthecatalystpowderinthereactor
itself.
➢Thecatalystpowdergraduallybecomesheavier,duetocoatingwith
carbon,andsettlestothebottom,fromwhereitisforcedbyanairblast
toregeneratormaintainedat600
0
C.
➢Inregenerator,carbonisburntandtheregeneratedcatalystthenflows
throughastand-pipeformixingwithfreshbatchofincomingcrackingoil.
MATRUSRI
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Moving-bed (Fluid-bed) Catalytic Cracking

73. 73
➢Atthetopoftheregeneratorthereisaseparator,whichpermitsonly
fluegasestopassout,butholdsbackcatalystparticles.
➢Thecrackedoilvapoursfromreactorarepassedtothefractionating
columnwhereheavyoilisseparated.
➢Thevapoursarethenpassedthroughthecoolerwheregasoline
condensesalongwithsomegases.
➢Thisisthensenttoastabilizerwherethedissolvedgasesareremoved
andpuregasolineisrecovered.
MATRUSRI
ENGINEERING COLLEGE

74. 74
MATRUSRI
ENGINEERING COLLEGE

75. 75

76. Internal Combustion Engine
76
MODULE-7: KNOCKING, OCTANE AND CETANE RATING
MATRUSRI
ENGINEERING COLLEGE

77. Internal Combustion Engine
77
MATRUSRI
ENGINEERING COLLEGE

78. Knocking
Itisasharprattlingsoundproducedintheinternalcombustionengine
duetoimmatureignitionoftheairgasolinemixture.
Thepresenceofsomeconstituentsinthegasolineusedcausesthe
rateofoxidationbecomessogreatthatlastportionofthefuel-air
mixturegetsignitedinstantaneouslyproducinganexplosive
violencecalled‘Knocking’.
Effects:
Knockingcauseshugelossofenergy,damagesthepistonand
cylindertherebylossofefficiency.
78
MATRUSRI
ENGINEERING COLLEGE

79. Knockingishighwhenthefuelshavestraightchainparaffin’sandlow
whenfuelscontainaromaticandbranchedchains.
Straightchainparaffins>Branchedchainparaffins>Cycloparaffins>
Olefins>Aromatics
Knockingcanbeminimizedbyaddingantiknockingagentslike
Tetraethyllead,Isopentene,methyltertiarybutyletheretc.in
gasoline.
79
MATRUSRI
ENGINEERING COLLEGE

80. OCTANE NUMBER (or) OCTANE RATING
Itisdefinedasthepercentageofiso-octaneinamixtureofiso-octane
andn-heptanethathasthesameknockingcharacteristicsofthefuel
underexamination.
For Ex: A fuel with octane number 60 will give the same knocking as
the mixture by volume of 60% iso-octane and 40% n-heptane.
80
MATRUSRI
ENGINEERING COLLEGE

81. CETANE NUMBER (or) CETANE RATING
Itisdefinedasthepercentageofcetane(n-hexadecane)inamixtureof
cetaneand2-methylnaphthalenethatwillhavethesameignition
characteristicsasthedieselfuelunderexamination.
Cetanehas a very short ignition lag and hence its cetanenumber is taken
as 100.
Ontheotherhand2-methylnaphthalenehasalongignitionlagand
henceitscetanenumberistakenaszero.
81
MATRUSRI
ENGINEERING COLLEGE

82. Thecetanenumberdecreasesinthefollowingorder:
n-alkanes>Cycloalkanes>alkenes>branchedalkanes>aromatics
Straightchainalkaneshavehighignitionqualitywhereasaromatichave
poorignitionquality.
Thus,thehydrocarbonswhicharepoorgasolinefuelsarequitegood
dieselfuels.
Thecetanenumberofadieseloilcanbeincreasedbyaddingadditives
suchasEthylhexylnitratecalleddopes.
82
MATRUSRI
ENGINEERING COLLEGECETANE NUMBER (or) CETANE RATING

83. LPG (Liquefied Petroleum Gas)
LPGisthemixtureofpropaneandbutanewithsmallamountsofethane
andpropeneobtainedfromgaswells.
Thesearecompressedtoformliquid.
ItissuppliedincylinderswithbrandnamessuchasBharath,HPand
Indanegas.
ThecalorificvalueofLPGis27,800kcal/m
3
.
83
MODULE-8:GASEOUSFUELS
MATRUSRI
ENGINEERING COLLEGE

84. Advantages:Itishighlyknockresistantwithhighcalorificvalueand
burnscleanly.Itishasgoodflexibilityandportabilitytosupply.
Disadvantages:Duetofaintodour,leakagecannotbedetected.
Uses:Itisusedasdomesticfuel,industrialfuelandmotorfuel.
84
MATRUSRI
ENGINEERING COLLEGE
LPG (Liquefied Petroleum Gas)

85. CNG (Compressed Natural Gas)
Natural gas is a mixture of mainly methane (60-95%) with small amounts
of ethane, H
2, CO
2and He.
It is stored and supplied as compressed natural gas (CNG) at a pressure
of 16 to 25 bar in cylinders.
The calorific value of CNG is 12000-14000 kcal/m
3
.
85
MATRUSRI
ENGINEERING COLLEGE

86. Advantages:
CNGisthecheaperfuelthanpetrolanddiesel.
Itisacleanestandleastenvironmentallyimpactingalternativefuel.
VehiclespoweredbyCNGproducelesscarbonmonoxideand
hydrocarbon(HC)emission.
Uses:
Asmotorfuel.
Aslocomotivefuel.
Alsousedasdomesticfuel.
86
MATRUSRI
ENGINEERING COLLEGE
CNG (Compressed Natural Gas)

87. MODULE-9: COMBUSTION
➢It is an exothermic chemical reaction.
➢It is accompanied by development of heat and light at a rapid rate,
so that temperature rises considerably.
Ex:C + O
2→CO
2+ 97 kcal
➢For proper combustion, the substance must be brought to its
ignition temperature.
MATRUSRI
ENGINEERING COLLEGE

88. Ignition Temperature
Itistheminimumtemperatureatwhichthe
substanceignitesandburnswithoutfurther
additionofheatfromoutside.
OR
Thelowesttemperatureatwhichasubstance
catchesfireandundergoescombustionliberating
heatandlightiscalledignitiontemperature.
MATRUSRI
ENGINEERING COLLEGE

89. Calculation of Air Quantities: Principles
➢Substances always combine in definite proportionsand these
proportions are determined by the molecular masses of the substances
involved and the products formed.
➢For Ex: C + O
2→CO
2
Mass proportions: 12 32 44
➢The above equation indicates that mass proportions of carbon, oxygen,
and carbon dioxide formed are 12: 32: 44 respectively.
➢Similarly, Mass proportion of Hydrogen: 4:32:36
➢2H
2+ O
2→2H
2O
Mass proportions: 2x2=4 322x18=36
MATRUSRI
ENGINEERING COLLEGE

90. ➢22.4L of any gas at STP has a mass equal to its 1 mole.
Ex: 22.4L of CO
2at STP will have a mass of 44g, because 44g is its
molecular mass.
➢Air contains 21% of oxygen by volume.
➢Mass percent of oxygen is 23 in air.
MATRUSRI
ENGINEERING COLLEGECalculation of Air Quantities: Principles

91. ➢Molecularmassofairistakenas28.94gmol
-1
.
➢MinimumO
2required=TheoreticalO
2required–O
2presentinthefuel.
➢MinimumO
2requiredshouldbecalculatedonthebasisofcomplete
combustion.
➢Themassofthedryfluegasesformedshouldbecalculatedby
balancingthecarboninthefuelandcarboninthefluegases.
➢Themassofanygascanbeconvertedtoitsvolumeatcertain
temperatureandpressurebyusingthegasequation:
PV = nRT
WhereP=Pressureofgasinatmosphere;
V=Volumeofgasinlitres;
n=numberofmolesofthegas;
T=TemperatureonKelvinscale.
MATRUSRI
ENGINEERING COLLEGECalculation of Air Quantities: Principles

92. ➢Available hydrogen = Mass of hydrogen –(Mass of oxygen/8)
2H
2+ O
2→2H
2O
Mass proportions: 4 32
➢Therefore, Theoretical amount of oxygen required for the complete
combustion of 1 kg solid or liquid fuel =
MATRUSRI
ENGINEERING COLLEGECalculation of Air Quantities: Principles

93. ➢Since the percentage of oxygen in air by mass is 23, so amount of air
required theoretically for combustion of 1 kg of fuel =
MATRUSRI
ENGINEERING COLLEGECalculation of Air Quantities: Principles

94. Numerical Problems
✓Calculate the weight and volume of air required for the combustion of 3
kg of coal?
Solution:
Amount of air required for combustion of 3 kg C
MATRUSRI
ENGINEERING COLLEGE

95. Numerical Problems;
✓Agasusedinaninternalcombustionenginehadthefollowing
compositionbyvolume:H
2=45%,CH
4=36%,CO=15%,N
2=4%.Findthe
volumeofairrequiredforthecombustionof1m
3
ofthegas?
1 m
3
of the gas contains Combustion Reaction Volume of O
2required (m
3
)
H
2(45%) = 0.45 m
3
H
2+ ½ O
2→H
2O 0.45 x 0.5 = 0.225
CH
4(36%) = 0.36 m
3
CH
4 + 2 O
2→CO
2+ 2 H
2O 0.36 x 2 = 0.720
CO (15%) = 0.15 m
3
CO + ½ O
2→CO
2 0.15 x 0.5 = 0.075
N
2(4%) = 0.04 m
3
Total = 1.020
Therefore, volume of air required per m
3
of gas
MATRUSRI
ENGINEERING COLLEGE

96. ✓Agaseousfuelhasthefollowingcompositionbyvolume.CH
4=5%,H
2=20%,
CO=25%,CO
2=6%andrestN
2.If20%excessofairisusedforcombustion,
thencalculatevolumeofairsuppliedperm
3
offuelandcompositionofdry
fluegases?
Substance Combustion Reaction Volume of O
2 Volume of dry
required(m
3
) product(m
3
)
CH
4(5%) = 0.05 m
3
CH
4 + 2 O
2→CO
2+ 2 H
2O 0.05 x 2 = 0.1CO
2= 0.05 x 1 = 0.05
H
2(20%) = 0.2 m
3
H
2+ ½ O
2→H
2O 0.20 x 0.5 = 0.1--
CO (25%)= 0.25 m
3
CO + ½ O
2→CO
2 0.25 x 0.5 = 0.125CO
2= 0.25 x 1 = 0.2525
CO
2(6%) = 0.06 m
3
from fuel CO
2= 0.06
N
2 (44%) = 0.44 m
3
from fuel N
2= 0.44
Total = 0.325 m
3
Total CO
2= 0.36 m
3
N
2= 0.44 m
3
Volume of air required using 20% excess per m
3
MATRUSRI
ENGINEERING COLLEGE

97. Calculation of dry products of gases:
•CO
2= 0.36 m
3
•O
2= 20% of 0.325 m
3
=
•N
2= 0.44 m
3
+ 1.857 m
3
x 79/100 of air = 1.907 m
3
Total volume of dry products = 0.36 + 0.065 + 1.907 = 2.332 m
3
MATRUSRI
ENGINEERING COLLEGE