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  TRANSPORT PHENOMENA RESEARCHPAPER

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  PRESENTATION

BY 

  GROUP

(A)

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  MEMBERS

  . SIKANDER ALMANI 09CH02

(G.L)

2. NAVEED ALI KOONDHAR 09CH70

3. ABDUL BASIT KAZI 09-08CH39

. S!ED SHAHZEB ALI SHAH 09CH9

". NA#EEB ASGHAR SOOMRO 09CH99

GROUP

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WHAT IS SOLID OXIDE FUEL CELL ?A solid oxide fuel cell SOFC! is "# elec$%oc&e'ic"l co#(e%sio# de(ice $&"$)%oduces elec$%ici$* di%ec$l* f%o' oxidi+i#, " fuel-Fuel cell de(ices "%e " %")idl* ,%o.i#, $ecolo,* $&"$ co#(e%$ c&e'ic"le#e%,* di%ec$l* i#$o elec$%ici$* "#d &e"$ .i$& &i,& e/cie#c* "#d lo. )ollu$io#

%"$es-C"$&ode T&e c"$&ode0 o% "i% elec$%ode0 is " $&i# )o%ous l"*e% o# $&e elec$%ol*$e .&e%eox*,e# %educ$io# $"1es )l"ce-A#ode T&e ce%"'ic "#ode l"*e% 'us$ 2e (e%* )o%ous $o "llo. $&e fuel $o 3o.

$o."%ds $&e elec$%ol*$e- Li1e $&e c"$&ode0 i$ 'us$ co#duc$ elec$%o#s0 .i$&io#ic co#duc$i(i$* " de4#i$e "sse$-Elec$%ol*$e T&e elec$%ol*$e is " de#se l"*e% of ce%"'ic $&"$ co#duc$s ox*,e# io#s- I$selec$%o#ic co#duc$i(i$* 'us$ 2e 1e)$ "s lo. "s )ossi2le $o )%e(e#$ losses f%o'le"1",e cu%%e#$s-

Pol"%i+"$io#sPol"%i+"$io#s o% o(e% o$e#$i"ls "%e losses i# (ol$" e due $o i' e%fec$io#s i#

 Introduction of basic terms for better understanding….

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Introduction

 

A co%e co')o#e#$ i# " &*d%o,e#52"sed e#e%,* eco#o'*0 &"s $&e"d("#$",es

 &i,& e#e%,* co#(e%sio# e/cie#c*0

lo. )ollu$io#0

#o de)e#de#c* o# de)le$i#, fossil %esou%ces-

s$ill li'i$ed 2* issues suc& "s &i,& cos$ "#d lo. Du%"2ili$*-

WORK OF OTHER RESEARCHERS

P%i#1e* et al. developed a computational fuid dynamics model.

Rec1#",le et al. simulated the o)e%"$io# of " SOFC .i$& $&%ee 3o.co#4,u%"$io#s6 co53o.0 cou#$e%53o.0 "#d c%oss 3o.-

A self co#sis$e#$ SOFC 'odel 2"sed o# $&e si#,le5do'"i# f%"'e.o%1 ."sde(elo)ed 2* P"s"o,ull"%i "#d W"#, $o sol(e $&e co#se%("$io# e7u"$io#sfo% '"ss0 'o'e#$u'0 s)ecies0 $&e%'"l e#e%,* "#d elec$%ic c&"%,e "lo#,

.i$& $&e elec$%oc&e'ic"l 1i#e$ics-

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 PICTORIAL MODEL AND MECHANISM

  A solid oxide fuel cell is made up of four layers, three of which are ceramics. A single cell consisting of these four layers stacked together is typically only a few millimeters thick. Hundreds of these cells are then connected in series to form what most people refer to as an "SOFC stack". he ceramics used in SOFCs do not !ecome electrically actie until they reach ery high temperature and as

a conse#uence the stacks hae to run at temperatures ranging from $%% to &,%%% 'C. (eduction of oxygen into oxygen ions occurs at the cathode. hese ions can then diffuse through the solid

oxide electrolyte to the anode where they can electrochemically oxidi)e the fuel. *n this reaction, a water !yproduct is gien off as well as two electrons. hese electrons then flow through an

external circuit where they can do work.he cycle then repeats as those electrons enter the cathode material again.

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Pe%fo%'"#ce Model

  Accou#$i#, fo% ("%ious (ol$",e losses0 o% o(e%5)o$e#$i"ls0 i#(ol(ed i#$&e o)e%"$i#, of " fuel cell0 " $*)ic"l ex)%essio# of $&e cell (ol$",e-

  Ucell, may be written in terms o the current density, i. The voltage o aSOFC, Ucell, is related to the open cell voltage, , and various losses, ! .

  W&e%e $&e su2sc%i)$s Ohm., act., and conc. imply Ohmic, activationand concentration losses, %es)ec$i(el*-

  T&e o)e# ci%cui$ )o$e#$i"l " depends on the temperature and gascomposition at the elec$%odes-

  T&e (ol$",e losses "%e "ssoci"$ed .i$& $&e elec$%oc&e'ic"l %e"c$io#s "$$&e $&%ee5)&"se 2ou#d"%*0 "#d "%e "8ec$ed 2* $&e $e')e%"$u%e0)%essu%e0 ,"s 3o.5%"$e "#d co')osi$io#0 elec$%ode9'e'2%"#e'"$e%i"ls0 "#d cell desi,#s-

  T&e losses co#sis$ of )"%$ $&e &e"$ ,e#e%"$io# i# "# o)e%"$i#, fuel cell-

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Pe%fo%'"#ce 'odel co#$6!

 

  T&e i#$e%#"l %esis$"#ce '"* 2e o2$"i#ed ex)e%i'e#$"ll* o% 2ees$i'"$ed f%o' co#duc$i(i$* d"$" "#d $&ic1#ess of e"c& l"*e%-

  : "#d ; %e)%ese#$ $&e $&ic1#ess "#d co#duc$i(i$*0 %es)ec$i(el*-

  U#de% o)e# ci%cui$ co#di$io#s0 $&e %e"c$"#$ "#d )%oduc$ co#ce#$%"$io#s

"$ $&e $&%ee )&"se 2ou#d"%ies "%e e7u"l $o $&ose i# $&e 2ul1 c&"##el3o.-

  Du%i#, cell o)e%"$io# .i$& #o# +e%o cu%%e#$ de#si$*0 co#ce#$%"$io#,%"die#$s de(elo) "c%oss $&e cell0 %esul$i#, i# lo.e% co#ce#$%"$io# "$ $&e$&%ee5)&"se 2ou#d"%ies "#d co#ce#$%"$io# losses-

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 Th concntr!tion "o### $!% & 'r##d

 

 To c"lcul"$e $&e co#ce#$%"$io# losses0 $&e %el"$io#s&i) 2e$.ee# $&e )"%$i"l )%essu%es "$ $&e $&%ee5)&"se2ou#d"%* "#d $&e cu%%e#$ de#si$*< i0 'us$ 2e de$e%'i#ed-

= is $&e $%"#sfe% coefficie#$0 n the number o electrons transerred in asingle elementary rate#limiting %e"c$io#0 "#d io is the e$change current

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So"id O'id Fu" C"" IN NUT SHE

 

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 %ass transer 

Co#(ec$i(e '"ss $%"#sfe% )l"*s "# i')o%$"#$ %ole i# $&e 'ic%o5c&"##els0 .&e%e $&e N"(ie%5S$o1es e7u"$io#s ,o(e%# $&e(eloci$* dis$%i2u$io#s-

* i# th $i'tur dn#it% + , i# $!## -r!ction + u i# "oc!" ."ocit%+

/ i# th di0u#ion co1cint !nd I# ! .o"u$tric #ourc tr$2D"%c*>s l". '"* 2e "))lied $o $&e )o%ous elec$%odes

A$ $&e i#$e%f"ce 2e$.ee# $&e elec$%odes "#d $&e elec$%ol*$e0 $&e sou%ce9si#1 $e%' )e%u#i$ "%e"0 fo% " ,i(e# s)ecies %e"c$"#$9)%oduc$! '"* 2e .%i$$e# "s6

W&e%e M is 'olecul"% #u'2e% of elec$%o#s i#(ol(ed i# $&e elec$%oc&e'ic"l

%e"c$io#0 F is F"%"d"*>s co#s$"#$ "#d i is the local current density at the interace.

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Heat  transfer 

 Co#(ec$i(e &e"$ $%"#sfe% is $&e do'i#"#$ $%"#sfe% 'ec&"#is' i# $&e'ic%o c&"##els0 .&ile co#duc$io# is i')o%$"#$ i# solid '"$e%i"ls "f$e%$&"$ co#(ec$io# %ule i$-

 T&e $o$"l e#e%,* c&"#,e %esul$i#, f%o' $&e %e"c$io# is $&e di8e%e#ce i#e#$&"l)* of fo%'"$io# & and @i22>s e#e%,* of fo%'"$io# -

which is 'theoretically( converted into electricity) the remaining is

co#(e%$ed i#$o &e"$-I# %e"li$*0 elec$%ic"l O&'ic! "#d "c$i("$io# losses0 c"use "ddi$io#"lc&e'ic"l e#e%,* $o 2e i%%e(e%si2l* co#(e%$ed i#$o &e"$ %"$&e% $&"#elec$%ici$*!-

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 Nu$ric!" i$"$nt!tion

 

 T*)ic"l SOFC u#i$ is s*''e$%ic "2ou$ $&e 'id5)l"#es of $&e "i% "#d fuelc&"##els-

 T&e ,o(e%#i#, e7u"$io#s .e%e #u'e%ic"ll* sol(ed 2* $&e co#$%ol (olu'e52"sed4#i$e (olu'e 'e$&od-

 T&e cou)li#, of $&e )%essu%e "#d (eloci$* 4elds ."s $%e"$ed (i" $&e SIMPLER

)%essu%e co%%ec$io# "l,o%i$&'-

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IN THIS RESEARCH PAPER WE COME TO NOWBB

o  * mathematical model or a planar solid o$ide uel cell 'SOFC(was constructed.

o The temperature distribution and the cell perormance werecalculated using unit model with double channels o co#fow pattern.

o The governing e+uations or mass continuity, momentumconservation,energy conservation and species conservation werediscretied with the -nite volume method'F%(.

o The water production and the hydrogen in the anode were ta/en

into consideration in the model.o The e0ects o the anode thic/ness, the operating conditions andvarious losses on the calculated results were investigated.

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 T.o '"o% ,%ou)s of )"%"'e$e%s "%e %es)o#si2le fo% $&e o(e%"ll cell)e%fo%'"#ce-

! O)e%"$i#, )"%"'e$e%s Temperature, pressure, gas composition(

'1( 2esign parameters 'Thic/ness of cell co')o#e#$s!

A ,ood u#de%s$"#di#, of $&e e8ec$s of $&e desi,# "#d o)e%"$i#,

co#di$io#s o# $&e fuel cell )e%fo%'"#ce is %e7ui%ed $o %educe $&ec")i$"l cos$ "#d i')%o(e $&e %eli"2ili$*-

Eect of operating pressure on SOFC performance

()E8ec$s of ("%ious o)e%"$i#, )%essu%e o# $&e cell (ol$",e is s&o.# i#Fi,- - A$ &i,& o)e%"$i#, )%essu%e 2"%-

()

 $&e SOFC )o$e#$i"l ."s fou#d $o dec%e"se 'o#o$o#ic"ll* .i$&i#c%e"si#, cu%%e#$ de#si$*-

() A$ "# o)e%"$i#, )%essu%e of G 2"%-0 $&e SOFC )o$e#$i"l dec%e"sedsli,&$l* .i$& i#c%e"si#, cu%%e#$ de#si$* f%o'G $o A9' "#d$&e# dec%e"sed sli,&$l* .i$& " fu%$&e% i#c%e"se i# cu%%e#$ de#si$*-

() T&is is due $o $&e f"c$ $&"$ $&e )%essu%e co#$%i2u$io# $o $&e Ne%#s$

)o$e#$i"l is lo,"%i$&'ic i# #"$u%e-

R#u"t# o- th $od"in3 #tudi#

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CONT6

 

Eect of fuel ow rate on the cell performance

  Po.e% cu%(es fo% $&e "#ode su))o%$ed cell $es$s o)e%"$i#, "$ J .i$&,"s 3o. %"$es of K-5 "#d K-5K ' s

  I$ %e(e"ls $&"$ o#l* sli,&$ di8e%e#ce of cu%%e#$ de#si$* fo% $.o di8e%e#$ ,"s3o. %"$es i# $&e %e,io# of &i,&e% cell (ol$",e .&ile $&e di8e%e#ces ex)"#ds$&e dec%e"se of cell (ol$",e-

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 Eect of anode thickness

Hydrogen eld A$ $&e "#ode9elec$%ol*$e i#$e%f"ce0 i# $&e "#ode 'iddle $&e ("lues of &*d%o,e#'"ss dec%e"ses "s $&e "#ode $&ic1#ess i#c%e"ses0

h%dro3n $!## 4 56 !nod thic7n##

Fo% "ll $&e "#ode $&ic1#ess0 &*d%o,e# '"ss is loc"$ed "$ $&e si$e si$u"$ed i#co#$"c$ .i$& $&e "#ode c&"##el-

Steam water eld 

  W"$e% loc"li+"$io# is "lso i#3ue#ced 2* "#ode $&ic1#ess

  T&e lo.es$ ("lue is o2$"i#ed fo% &i,& "#ode $&ic1#ess-

  T"2le s&o.s $&"$ $&e '"xi'u' %"$e of c%e"$ed ."$e% f%"c$io# "$ $&e"#ode9elec$%ol*$e i# $&e "#ode 'iddle0 $&e ("lues of ."$e% f%"c$io# i#c%e"ses"s $&e "#ode $&ic1#ess i#c%e"ses-

  W"$e% )%oduc$io# 2eco'es l"%,e% "s $&e "#ode $&ic1#ess i#c%e"ses-

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 /n#it% ro8" !nd t%# o- -u"c""# !nd !"ic!tion#2

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 Conc"u#ion

 A co')u$"$io#"l si'ul"$io# of $&e $%"#s)o%$ "#d elec$%oc&e'ic"l )&e#o'e#"i# " )l"#"% SOFC-

S$e"' ."$e%0 &*d%o,e# "#d $&e $e')e%"$u%e dis$%i2u$io#s0 u#de% ("%iouslosses0 o)e%"$i#, co#di$io#s "#d di8e%e#$ ("lues of $&ic1#ess &"(e 2ee#)%ese#$ed-

 T&e u#i7ue fe"$u%es of $&is 'odel "%e $&e i')le'e#$"$io# of $&e (ol$",e5$o5

cu%%e#$ "l,o%i$&' "#d $&e cou)li#, of $&e )o$e#$i"l 4eld .i$& $&e %e"c$"#$s)ecies co#ce#$%"$io# 4eld0 .&ic& "llo.s fo% " 'o%e %e"lis$ic s)"$i"l ("%i"$io#of $&e elec$%oc&e'ic"l 1i#e$ics-

H*d%o,e# '"ss $%"#sfe% is fu#c$io# of $&e "#ode $&ic1#ess-

3arametric analyses showed that all temperatures decreased with increasinglosses.

 *nother important -nding is that the anode thic/ness has signi-cant e0ect ongases distribution, along the main fow channel. For gas fow rate o 4".5"#4m6 s75,

The pea/ power density was 689"4:m71, which was about 8.9; higher thanthat o 4".5"#< m6 s75 gas fow rate.

The results o this paper provide better understanding on the coupled

heat=mass transer and electrochemical reaction phenomena in an SOFC. Themodel developed can serve as a useul tool or SOFC design optimiation

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AS UESTIONS?

UESTIONS FOR @ROUP MEMERSNOT FOR P%ese#$"$o%