Improved process technology in oil and gas .pdf

Process technology

1. PTE 512: PROCESS TECHNOLOGY
Course Lecturer
Engr. Dr. Jeffrey O. Oseh
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering

2. Elective 3 credit units
Pre-requisite: PET 310 (Heat and Mass Transfer)
COURSE OUTLINES
1.Heattransfer:conduction,convection,and
radiation
2.HeatExchangers
3.Distillation
4.Particlesfallsinliquidcyclones
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology

3. Introduction to heat transfer
Inthiscourse,theprocessoftransferofheat
between bodiesby(conduction,convection,and
radiation)willbediscussed.Differentprocesses
associatedwiththetransferofheatbyconduction,
convection,andradiationwillalsobediscussed.
Further,theperformance ofheatexchangers,
distillationunits,andthefallingofparticlesinliquid
cycloneswillbehighlighted.
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology

4. What is heat transfer?
Heat:isthetransferofflowduetotemperaturedifferencebetween
twoobjects.
Heattransferisafundamentalpartofthermalengineering.Itisthe
scienceoftherulesgoverningthetransferofheatbetweensystemsof
differenttemperatures.itdealswiththegeneration,use,conversion,and
exchangeofthermalenergybetweenphysicalsystems.Itcanbe
definedasthemovement ofenergyfromone
substance(warmer)toanother(colder).
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology

5. 3 ways energy (heat) is transferred
Figure 1
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology

6. 3 ways energy (heat) is transferred
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology

7. Thermal Energy Transfer
Thermalenergytransferisheatmovingfromawarmerobjecttoacoolerobject.Heatwillcontinueto
moveuntilbothsubstancesareatthesametemperature.Themorekineticenergyofanobject,themore
itsthermalenergy.Thefastertheparticlesaremoving,thehottertheobjectbecomes.Thegreaterthe
differenceintemperaturebetweenthesubstances,thefastertheheatwilltransfer.
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
Cold Hot

8. HEAT CONDUCTION
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
•Heatistransferredfromoneparticleofmatterto
anotherinanobjectwithoutthemovement oftheobject.
Itisthetransferofheatfromonebody(warmer)tootherbody
(colder)bymeansofphysicalcontact.
•CONDUCTION = DIRECT CONTACT
•Direct collision of molecules
Cold Hot

9. HEAT CONDUCTION
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
Cold Hot
•Atomstransferenergytothe
Atomsnexttothem.
•Themoleculesdonothaveto
bethesamesubstance.

10. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
Example of Conduction
Conduction: Requires
material (medium) to
transfer heat.
Medium = Metal

11. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
•Thinkofametalspoonormetalhandleinapotofwater
beingheated.
•Thefast-movingparticlesofthefirecollidewiththe
slow-movingparticlesofthecoolpot.
•Becauseofthesecollisions,theslowerparticlesmove
fasterandheatistransferred.
•Thentheparticlesofthepotcollidewiththeparticlesin
thewater,whichcollidewiththeparticlesatoneendof
thespoon.
•Astheparticlesmovefaster,themetalspoongetshotter.
Thisprocessofconductionisrepeatedallalongthe
metaluntiltheentirespoonishot.
•Medium=metalspoonorhandleofthe
pot
•Apieceofcheesemeltsasheatistransferredfromthe
meattothecheese(Directcontact).
Example of Conduction

12. HEAT CONVECTION
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
Heattransferbyconvection isthe
transferofheatthroughthefluid(liquids
andgases)movementofcurrents.
Heatistransferredbycurrentswithin
thefluidorgas.Thesefluidcurrents
developedduetotemperaturedifference
{withinafluid,(liquid/gas)orbetweena
fluidandasolid}ortheuseofa
pump/fan.
•Convectionmovesinacircularpattern.
•Convection:Requiresmedium to
transferenergy.
Cool air
Warm air

13. HEAT CONVECTION
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
Warmfluids(air)
rises,cool,sink,
andarewarmed
again.
•The radiator
warmstheroom
bywarming the
airaround it.
Then,thewarm
airtransfersheat
totherestofthe
room through
convection.

14. HEAT CONVECTION
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
•Asairabove
the road
warms up,it
risesanditis
replaced by
cooler air,
forming a
convection
current.

15. Examples of heat convection
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
Haveyouevernoticedthattheairneartheceilingis
warmerthantheairnearthefloor?Orthatwaterina
pooliscooleratthedeepend?
Examples:airmovementinahome,potofheatingwater.

16. HEAT RADIATION
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
•Radiationisthetransferofenergyby
electromagneticwaves
•Itisthetransferofenergybymeans
ofphotonsinelectromagneticwaves.
•Emission and absorption of
electromagnetic radiationbetween
twosurfaces
•RadiationdoesNOTrequirematter
(medium)totransferthermalenergy
•Radiation=Radiates(heatescaping
thesun)
•Heatfromthesunradiatesthrough
emptyspacetoearth.

17. HEAT RADIATION
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
•Thereisnodirectcontactbetweenthesubstances

18. HEAT RADIATION
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
Radiationmaycomefrom
othersources
Haveyoueversattoo
closetoacampfire
whilecooking?
You areenjoyingthe
warmth …..onlyto
noticethatyourskinis
reallywarm?

19. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
EXAMPLES OF RADIATION
1.Fire
2.Heat Lamps
3.Sun

20. •Automobile:Radiatorandenginecoolant
•Electronics:Coolingofmotherboard/CPU byfan
•Pharmaceutical:Freezedryingofvaccines
•Metallurgical:Heating/coolingduringsteelmanufacture
•Chemical:Condensation,boiling,distillationofchemicals
•Home:Refrigerator,AC,heater,dryer,stove,microwave
SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
HEAT TRANSFER IN VARIOUS INDUSTRIES

21. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
RECAP OF HEAT TRANSFER
3 Ways Energy (Heat) is Transferred
*Transferred in
rays or waves
*Energy from the
Sun warms the
Earth
Mode: Radiation
*Transfer ofheat
(energy) that
happens when
moleculesbumpinto
eachother
*Objects must be
touching
“Conduction is
touching”
Mode:Conduction
*Transferofheatby
theflowofmaterial
*Inwarm air,the
molecules move
apart,soitisless
denseandrises
*Incoolerair,the
molecules move
closertogether,so
itismoredense
andsinks.
Mode:Convection

22. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
RECAP OF HEAT TRANSFER

23. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
CONDUCTION HEAT TRANSFER
Basics of Conduction
•Conductioninvolvesthetranslationofvibrationofmoleculesalonga
temperature gradientastheyacquirethermalenergy(mainlyanalyzed
withinsolids;however,ittakesplaceinliquidsandgasesalso).
–Actualmovement ofparticlesdoesnotoccur
•Goodconductorsofelectricityaregenerallygoodconductorsofheat
•Thermalconductivity(k)isusedtoquantifytheabilityofamaterialto
conductheat

24. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
HEATCONDUCTION MECHANISM
1.Bymolecularinteraction(e.g.gas)
Greatermotionofmoleculeathigherenergylevel(temperature)
impartsenergytoadjacentmoleculesatlowerenergylevels.On
takingheat,themoleculesremainsstationarybuttheyvibrateintheir
latticewhichimpartsenergyonneighbouringparticlesinthedirection
oflowtemperatureandhenceconductiontakeplace.
2.Bydriftoffreeelectrons.
Incaseofmetals,theyhavemorefreeelectronswhichmovesand
collideswithotherelectronssupplyingheatenergythuscausesthe
heattransfer.

25. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
RateofheattransferbyconductionisgivenbyFourier’slawofheatconductionas
follows:
Fourierlawstatesthattherateofheatconductionisproportionaltotheareameasured
normaltothedirectionofheatflow,andtothetempgradientinthatdirection.
Thenegativesignisusedtodenote/determine thedirectionofheattransfer(Lefttoright
orrighttoleft,heatgainedorheatlost)
Q:Energytransferredperunittime(W)
K:Thermalconductivity(W/mK);itisa+vequantity.Itisatransportpropertyandisa
characteristicofthewallmaterial.Itisusedtoquantifytheabilityofamaterialto
conductheat.
A:Areaofheattransfer(m²)
∆T:Temperaturedifferenceacrosstheendsofsolid(K)
∆x:Distanceacrosswhichheattransferistakingplace(m)
Q/A:Heatflux(W/m²)
JOSEPHFOURIER’SLAWOFHEATCONDUCTION

26. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
TEMPERATURE DIFFERENCE ACROSSASLAB
Figure1One–dimensionalheattransfer
byconduction
Slab: Q=kA(∆T/∆x)
∆T = T
1–T
2
ForthesamevalueofQ(example:useofaheateron
onesideofaslab),
For insulators (low k), “T
1–T
2” is large
For good conductors (high k), “T
1–T
2” is small
Forthesamevalueof“T
1–T
2”(example:fixedinside
temperatureofroomandoutsideairtemperature),
For insulators (low k), Q is small
For good conductors (high k), Q is large
Note:∆??????andAareassumedtobethesameinallofthe
abovesituations.

27. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
TEMPERATURE DIFFERENCE ACROSSASLABdx
dT
kq
x'' TEMPERATURE DIFFERENCE ACROSSASLAB
The–vesignisaconsequence of
thefactthatheatistransferredin
thedirectionofdecreasingtemp.
Applying Fourier'slawofheat
conduction permits determining
temperature distributionwithina
body.
Heat conduction isnormally
transferredfromawarmerbodytoa
coolerbody.L
T
k
L
TT
kq
x




21
''
????????????
????????????
=
??????
2−??????
1
�

28. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
HEATCONDUCTION ACROSSACYLINDER ANDASPHERE
r
i = r
1and r
o = r
2
Figure2Steady,one‐dimensionalheat
conductioninacylindricallayer
•Steadystateheattransferthroughpipesisinthenormaldirectiontothe
wallsurface
•Nosignificantheattransferoccursinotherdirections.
•Therefore,theheattransfercanbemodeledassteady‐stateand1-D.
•Thetemp.ofthepipewilldependonlyontheradialdirection,T=T(r),
asshowninFigure2.
•Since,thereisnoheatgenerationinthelayerandthermalconductivityisconstant,
theFourierlawbecomes:
�
∗
�??????�
=−�??????
�??????
��
1
Area of a cylinder ??????=2????????????�
Area at one end of the cylinder (outside) is ??????
2=(2????????????
2�)
Area at one end of the cylinder (inside) is ??????
1= (2????????????
1�)
??????
�=??????
2−??????
1, or ??????
�−??????
??????
????????????=??????
1−??????
2or ??????
??????−??????
�

29. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
Since, there is no heat generation in the layer and thermal conductivity is constant, the Fourier
law becomes:
�
∗
�??????�
=−�??????
�??????
��
Replace the area A with ??????=�??????��
�
∗
�??????�
=−�(�??????��)
�??????
��
2
Note �
∗
�??????�
=�
∗
�
Where �
∗
??????
is constant which may be separated and solved as follows by integration
�
∗
�
න
�
�
��
��
�
=−�??????��න
??????
�
??????�
�??????=�??????��න
??????
�
??????�
�??????
�
∗
�
��
�
�
�
�
=�??????��??????
�−??????
�
Rearrangement of the equation yields:
�
∗
�
=�
∗
�??????�
=�??????��
??????
�−??????
�
��
�
�
�
�
3
�
∗
�??????�
=
??????�−??????�
�
�??????�
4
Where,
�
�??????�=
��(����)
�??????��
is the conduction resistance of a cylinder 5

30. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
HEATCONDUCTION ACROSSACYLINDER ANDASPHERE
For A sphere:
•Followingtheanalysisabove,theconductionresistanceforthesphericallayercanbe
found:
�
∗
��ℎ
=
??????1−??????2
�
????????????ℎ
�
��ℎ=
�2−�1
4??????�
1�
2??????
Where area of a sphere is A = 4πr
2
�
��ℎis the conduction resistance of a sphere

31. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
BasicsofConvection
•Itinvolvestransferofheatby
movement ofmoleculesoffluid
(liquid or gas) due to
Temperaturesdifferenceswithina
fluidorbetweenafluidandasolid
object.
•Energyexchange between a
surfaceandanadjacentfluid.
OR
–Anexternalagencysuchasa
pumporafan
HEAT CONVECTION
Categories of Convection
•Free(ornatural)convection
–Doesnotinvolveanyexternalagencyincausingflow
–Heattransferbetweenbottomofvesselandfluidin
it.
•Fluid comes into contact with hot solid
• Fluid temperature near solid increases
• Fluid density near solid decreases
• This results in a buoyancy force that causes flow
• Rate of heat transfer (Q & h) depends on
–Temperature difference between fluid and surface
of solid
–Coolingofhumanbody
–Coolingofradiatorfluidincarengineduringidling
–ℎ
�??????�−���??????�:5-25W/m2K;ℎ
??????����−���??????�:20-100W/m2K

32. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
BasicsofConvection
•Itinvolvestransferofheatby
movement ofmoleculesoffluid
(liquid or gas) due to
Temperaturesdifferenceswithina
fluidorbetweenafluidandasolid
object.
•Energyexchange between a
surfaceandanadjacentfluid.
OR
–Anexternalagencysuchasa
pumporafan
HEAT CONVECTION
CategoriesofConvection
•Forcedconvection
Fluidisforcedtomovebyanexternalforce(pump/fan)
•Rateofheattransfer(Q&h)dependson
–Dimensionsandsurfacecharacteristics(smoothness)
ofsolid
•‘h’doesNOTdependon
–Temperature differencebetweenfluidandsurfaceof
solid
•‘h’stronglydependsonReynoldsnumber
–Whenallsystemandproductparameters arekept
constant,it
isflowrate(aprocessparameter)thatstronglyaffects
‘h’
–Externalagencysuchasfan/pumpcausesflow
–Coolingofradiatorfluidincarengineduringmotion
–Ice-creamfreezer(Blastair)
–Stirringapotofsoup
–Heattransferredfromcomputers(fan)
–ℎ
�??????�−���??????�:10-200W/m2K;ℎ
�??????�−���??????�:50-10,000W/m2K
–ℎ
��??????�??????�????????????����������������??????�:3,000-100,000W/m2K

33. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
Newton’s Law of Cooling for Convection
Rateofheattransferbyconvection(forheatingorcooling)isgivenbyNewton’slawofcoolingasfollows:
Q = h A (Ts -T∞)
Q:Energytransferredperunittime(W).
h:Convectiveheattransfercoefficient(W/m²K).Itdependsonconditionsintheboundarylayer,influencedby:
Surfacegeometry
Natureoffluidmotion
Arrangement ofthefluidthermodynamic andtransportproperties
A:Surfaceareaavailableforheattransfer(m²)
∆??????=Ts–T∞:Temperaturedifference(K)
Ts:Surfacetemperatureofsolidobject(K)
T∞:Freestream(orbulkfluid)temperatureoffluid(K).
�
∗
??????
�
2
=
�
??????
istheconvectiveheatflux.Thus,Newtonlawofcoolingoccurswhentheconvectiveheatflux�
∗
is
proportionaltothedifferencebetweenthesurfaceandbulkfluidtemperatureTsandT∞,respectively.

34. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
RADIATION HEAT TRANSFER
BasicsofRadiationHeatTransfer
(1)Nomediumisrequiredforitspropagation.
(2)Energytransferbyradiationismaximum whenthetwoSurfacesareseparatedbyvacuum.
(3)RadiationheattransferrateequationisgivenbytheStefan-Boltzmannlawofthermalradiation:
�
??????
=????????????
??????
;�=????????????????????????
??????
�
??????
:radiantheatflux
??????
�
�
q:rateofradiantenergyemission(W);
A:areaofemittingsurfaceorobject(m
2
);
T:absolutetemperature(K)
??????:Stefan-BoltzmannConstant=5.676x10
-8
W/m
2
-K
4
ε:Emissivityofsurface(rangesfrom0to1.0)

35. SchoolofEngineeringandEngineeringTechnology
DepartmentofPetroleumEngineering
PTE512:ProcessTechnology
SOLVED EXAMPLES
NEXT CLASS