University:
The Pennsylvania State University
Course:
CHE 220 | Introduction to Chemical Engineering Thermodynamics
Academic year:

2020
Views:

175

Pages:

8
Author:

study_genius

Topics Entropy * : 4.4 Ll Generation Lost Work * Reading for Today . , 6 4.5 47,48 is optional reading will be covered in the next lethre Generation Entropy :( 15570110 * Secondlaw adiabatic ,eat WIT ,nµa÷÷:÷÷ ✓ iii surroundings c- :÷i:i in Ettman closed isolated adiabatic 1570 Entropy Generation sgenzo universe AS )systCDDsun±O 057/0 : sgen=(DS)sys+4S)sur t . sgen statement sgen of 2nd LAW >o sgen=o Sgenao E94ir9kht . process 's : : ' irreversible reversible impossible 1kg of : Steam @ 1bar 3OouLismixedatiabaticaHy@conH.P , Haun SKI EXAMPEL : a- at 't ' trio } HF=Hi 51=82171 7.3588=6.7805 Atiabaticqo - #n¥=MHtMY¥} HF=Mhhttmmj hith5kgofwetteanr@1baraith15t.moiStVheCa1alntlfinalTSgen.MeIkgmz-5kgntunst.P Lj insulation . ,= HE H¥=( 1bar 2=2459.32 ) ~p×L= HV Hv pzdbar 3074.5 .44 .3o26 Final State mitmz Tz= T|= 300°C P :# 't Entropy : H✓= 26,4g HF -1459.3 ~DSgen=( MHNHSF XL= 0.0955 = = - 02137¥ mis , 70 - vk 0.0955 HL Sf=×cSL+G XDSV - generation :Sgen#Ds×stCµB°n Entropy 6.7805 - sv= :# 99.61 Pelbar SFI HF - mzsz EXAMPLE Z3mo1butane@5ooCismixedatiabaticaHyceconst.Pwith1mo1ofbutaneaf3oool.20baV.Determihefina1Temperatuwandentropybeneratim.so1utimAdtitima1DataiCph-l72J1mo1.kTsAEl14.37kCpII65-ltLHrap-13R2OJ1mo1.L.a.IiaYseEofHittYikFItIInL.iHv-HLtDHrap-Hz-HrtCpVCT2-TsAT1-5492O.6-1tEhergyBa1anu.AH '¥O niHHmH2 XL=¥t Hv - HL - 0.799 Final State 114.37 - PF= 20bar XKO -799 - Chitm )HF=0 HF=mt¥H2= N ,th~ 137301 mol VK EXAMPLE 'd Entropy Balance : Reﬀtath Calculate all entropies : picks ,=O from common Zant €# . 5¥Si+Cp4n¥*= ' Sv=SL+0ft÷Y = : ' ' = 129.93 SEXLSHCTXL )Sv= 38.104 It - - t It sogou.ADsyi.CA/Dsm#Hk(hithDSF - ~D 65.3583 52=5 vtcpvlnjhsa , Entropy Generation Jlmdk 31.2439 - Sgeni 22.481 Jlmotk his , - msz -22.481 Jtnolk EXAMPLE 2 - Variati : epeat with nz= 10 left as an exercise md . Lost Work : 2 PvoussQmzO.exchangesheutwithasingkbnth@To.paoafirstLawi.on-Qtw2gwQ-ou-W2ndLaWSgen-os-jIoZoss-0I-othfo-Tossen1lxWyoU-To0StToSsenw-mWidea1-DU-ToDSheatbathactua1WidealWiosTtT0Then.W-Wikea1tWlosTXLostworkisal1wayspositive-itrepvesentsapenaHyl.iftheprousspvotuceswork.lessisprotuuddvetoSgeniftheproussveqnivesworlsmoremustbedonetuetoSgen.tReversibleProus.iBestCasescenario.max work min Work produced consumed Example Solution 3 Aloafotbreakfreshfromtheovenislefttocoolinthe Kitchen .DE#rminetheehtropy generation : : Q= any MCPCTA ,z . TBR ) = 742 - KJ dQ=mtpdT DSnin= sgen.gs#+DSair=O.8727kJlKNoetosetf .Sgen=26t8KJ Assumptions T= opt To= m=0' ,z=Jd¥=mg>1nIAR = - 1.658 KJIK IBR KJIK 4.18 Taira Q 300k Tnt KJIK 20°C - = +2.531 5kg : plan DSB 375°F previous fitthisexampu tomxtketue either material , Wiostoto -10 move or . enovghtenersyforah tochmbto 330N 80kg person !