1 |STOICHIOMETRY (L.R., E.R., Extent of Reacon, Conversion, Yiel, Selecvit!"
#raconal Excess
fracti fractiona onall excessof excessof A
Selecvit!
( n A )feed ( n A )stoich ( n A )stoich −
=
Supplied Theo Exce Theo The −
=
=
Selectivity =
molesof desired desired product product formed molesof undesired undesired product product formed
(Example (Example 4.6-1, Felder, Felder, page 120) Acrloni!rile is "roduced in !he
#raconal Conversion
f =
molesreacted moles moles fed
M$l%le reacon, Yiel an Selecvit! Yiel Felder, Himmelblau and Gen. Chem. Defniton:
reacton o# "ro"lene, ammonia and o$%en: o$%en: C H' ( )H ( *+ + CH) ( H +. -he #eed con!ains /./ mole0 "ro"lene, +./0 ammonia, and 12./0 air. A #ractonal con3ersion o# /./0 o# !he limitn% limitn% reac!an! reac!an! is achie3ed achie3ed.. -akin% akin% // mol o# #eed #eed as basis, basis, de!ermine 4hich reac!an! is limitn%, !he "ercen!a%e b 4hich each o# !he o!her reac!an!s is in e$cess, and !he molar amoun!s o# all "roduc! "roduc! %as const!uen const!uen!s !s #or a /0 con3ersion con3ersion o# !he limitn% limitn% reac!an!. (Example 4.6-3, Felder, page 124) -he reactons C+H'
molesof desired desired product product formed Yield = molesthat molesthat would would have have beenformedif there there were were no side reactions reactions∧thelimiting reactant reactant had reacted reacted completely completely Yield =
Actual Theoretical
C+H5 ( H+ and
C+H' ( H + + CH5 !ake "lace in a contnuous reac!or reac!or a! s!ead s!a!e. -he #eed con!ains 26./ mole0 e!hane 7C +H'8 and !he balance iner!s 798. -he #ractonal con3ersion o# e!hane is /.6/, and !he #ractonal ield o# e!hlene is /.51. Calcula!e !he molar com"ositon o# !he "roduc! %as and !he select3i! o# e!hlene !o me!hane "roducton. (Old (Old Testa estame ment nt)) -he e!h e!hle lene ne o$ide o$ide reac! reac!an! an! used used in %lco %lcoll
Bha & Vora and Asokan:
moles moles of desire desired d produ product ct × Stoich. Stoich. Facto Facto r Yield = molesof specific specific reactant reactant consumed consumed
"roducton is made b "artal o$idaton o# e!hlene 4i!h an e$cess o# air o3er a sil3er ca!als!. -he "rimar reacton is +C +H5 ( + +C+H5. n#or! n#or!una una!el !el , some some o# !he e!hle e!hlene ne also also under under%o %oes es com"le!e o$idaton !o carbon dio$ide and 4a!er. ;u""ose !ha! 4i!h a #eed con!ainin% /0 e!hlene e!hlene and an e!hlene con3ersion con3ersion o# +60,
where, where, Stoich. Stoich. Factor Factor stoichiometricreuirement of the the specific specific reactant reactant per per mole of the desired desired product product =
B:
a ield o# 2/0 o$ide is ob!ained #rom !his reac!an!. Calcula!e !he com"ositon o# !he reac!or ou!le! s!ream.
& |STOICHIOMETRY (L.R., E.R., Extent of Reacon, Conversion, Yiel, Selecvit!"
(Old Testament) Ace!aldehde, CHCH, can be "roduced b
ca!altc dehdro%enaton o# e!hanol, 3ia !he reacton C +H6H CHCH ( H+. -here is, ho4e3er, a "arallel reacton "roducin% e!hl ace!a!e +C+H6H
CHCC+H6 ( +H+. ;u""ose !ha! in a %i3en
reac!or !he conditons are ad>us!ed so !ha! a con3ersion o# ?60 e!hanol is ob!ained 4i!h an 2/0 ield o# ace!aldehde. Calcula!e !he com"ositon o# !he reac!or "roduc! assumin% !he #eed consis!s o# "ure e!hanol.
"rocess !o manu#ac!ure ace!lene, "ure o$%en and "ure me!hane are #ed !o !he ace!lene burner. -he cracked %as #rom !he burner has !he #ollo4in% com"ositon: H+: 6'.60, CH5: 6.+0, C+H5: /.0, C+H+: 1.60, CH': /.60, C: +6.20, C+: 5./0 and +: /.+0 7mole0 on dr basis8. Assume !ha! #ormaton o# o!her com"ounds, such as aromatcs, is ne%li%ible. For // kmol cracked %as, calcula!e 7a8 me!hane reuiremen!, 7b8 o$%en reuiremen!, 7c8 "roducton o# 4a!er, 7d8
(Problem 4., !"a# and $ora, page 1%) ;elect3e dehdro%enaton o# alkanes !o alkenes is a 4ell es!ablished "rocess. 9n !his "rocess, dehdro%enaton o# i@bu!ane is carried ou! on a "latnum
im"re%na!ed ca!als! a! 6/ ka % and 11 76// 8. -he #eed !o !he reac!or is "ure i@bu!ane alon% 4i!h /.16 kmol H + "er kmol o# i@ bu!ane. Hdro%en s!ream con!ains ?/0 H + and /0 me!hane 7b mole8. Follo4in% reactons are kno4n !o !ake "lace. i@C5H/ i@C5H2 ( H+ 78 i@Bu!ane i@Bu!lene Hdro%en i@C5H/ i@Bu!ane
(Problem 4.6, !"a# and $ora, page 1%) 9n !he BA;F oil uench
CH' ro"lene
(
CH5 e!hane
7+8
Ei!era!ure re"or!s 6/0 "er "ass con3ersion in a baer o# !hree reac!ors 4i!h 220 ield o# i@bu!lene. Calcula!e !he com"ositon o# !he "roduc! s!ream lea3in% !he fnal reac!or. (&e'on 4.%a, Felder, page 12) -he Dehdro%enaton o# e!hane !akes "lace in a s!ead@s!a!e contnuous reac!or. -he reacton is C +H'
C +H5 ( H+. ne hundred kmol*min o# e!hane is #ed !o !he reac!or. -he molar o4 ra!e o# H + in !he "roduc! %as s!ream is 5/ kmol*min. Calcula!e !he molar com"ositon o# !he "roduc! %as.
con3ersion o# me!hane, and 7e8 ield o# ace!lene "roducton. (Problem 4., !"a# and $ora, page 1*) 9n !he Deacon "rocess #or
manu#ac!urin% chlorine, hdrochloric acid %as is o$idied 4i!h air. -he reacton !akin% "lace is: 5 HCl ( + + Cl + ( + H+ 9# !he air is used in e$cess o# /0 o# !ha! !heoretcall reuired, and i# !he o$idaton is 2/0 com"le!e, calcula!e !he com"ositon b 3olume o# dr %ases lea3in% !he reac!or chamber. (Problem 4.12, !"a# and $ora, page 1*) -he analsis o# !he %as
en!erin% !he secondar con3er!er in a con!ac! sul"huric acid "lan! is 50 ;+, 0 + and 20 )+ 7on 3olume basis8. -he %as lea3in% !he con3er!er con!ains /.560 ;+ on ;@#ree basis 7b 3olume8. Calcula!e !he "ercen!a%e o# ;+ en!erin% !he con3er!er %eIn% con3er!ed !o ;. (Problem 4.13, !"a# and $ora, page 1*) A mi$!ure o# "ure carbon
dio$ide and hdro%en is "assed o3er a nickel ca!als!. -he !em"era!ure o# !he ca!als! bed is 622 76
8 and !he reac!or
"ressure is + a %. -he analsis o# !he %ases lea3in% !he reac!or
B:
' |STOICHIOMETRY (L.R., E.R., Extent of Reacon, Conversion, Yiel, Selecvit!"
sho4ed C+: 61.0, H+: 5.0, CH5: .'20 and C: /.+0 7b
(/llstraon 4, +adas'", page 3*) A "ure hdrocarbon %as a! 1/
3olume8 on a dr basis. -he reacton !akin% "lace in !he reac!or are:
burn! in a #urnace %i3in% a ue %as con!ainin% /.20 C+, .20 +,
is
C+ ( 5 H+ CH5 ( + H+
and !he res! ni!ro%en and iner!s. Calcula!e !he a!omic rato, H*C, and
and C+ ( H+ C ( H+
#rom !his !he #ormula o# !he #uel.
Find 7a8 !he con3ersion o# C+ "er "ass, 7b8 ield o# CH 5 in !erms o# C+ reac!ed, and 7c8 !he com"ositon o# !he #eed 73olume basis8.
(Example 6, arto page 1*) A "ure sa!ura!ed hdrocarbon 7CnH+n(+8
is burned 4i!h e$cess air. rsa! analsis o# !he "roduc!s o# (Problem 4.14, !"a# and $ora, page 1) Ace!aldehde is o$idied
combuston sho4s ?./20 C+, .'0 C, 6.+20 + and no #ree H+.
o3er silica %el 4i!h !he hel" o# air. -he mi$!ure is "assed o3er !ha!
Calcula!e: 7a8 -he #ormula o# !he hdrocarbon 7b8 0 e$cess air 7c8 k%
ca!als! a! 21 75 8. -he ou!%oin% dr %ases are #ound !o
dr air*k% o# hdrocarbon
con!ain 5.260 C+, 2.'60 ace!aldehde, 5.?0 acetc acid, +.660 + and '?./60 )+ b 3olume 7on dr basis8. For carrin% ou! dr
Based on !he "rocess dra4n in !he dia%ram, 4ha! is !he k% reccle *
analsis, 4a!er 4as frs! remo3ed #rom !he mi$!ure. Durin% !he
k% #eed i# !he amoun! o# K 4as!e is // k% L -he kno4n
4a!er remo3al, some acetc acid is also condensed.
com"ositons are inser!ed on !he "rocess dia%ram.
Calcula!e 7a8 !he "ercen!a%e con3ersion o# ace!aldehde, 7b8 !he "ercen!a%e ield o# acetc acid, 7c8 mass rato o# air !o ace!aldehde in incomin% #eed, 7d8 !he "ercen!a%e remo3al o# acetc acid durin% !he remo3al o# 4a!er, and 7e8 !he ac!ual analsis o# !he %ases lea3in% !he reac!or. (Problem 3, +adas'", page 3) Calcula!e 4ha! should be !he rsa!
analsis resultn% #rom !he com"le!e combuston 4i!h //0 e$cess air o# 7a8 J!hane, C+H' 7b8 )a"h!halene, C/H2. (Problem 1, arto, page 24) Calcula!e !he rsa! analsis o# !he
"roduc!s o# combuston u"on burnin% "ure he$ane 4i!h 20 e$cess air i#: 7a8 Combuston is com"le!e 7b8 260 o# !he C burns !o C +, !he res! !o C, molar rato o# H + !o C is :+.
B:
|STOICHIOMETRY (L.R., E.R., Extent of Reacon, Conversion, Yiel, Selecvit!"
(Problem 4.6, Felder, page 1%%) A ca!altc reac!or is used !o
"roduce #ormaldehde #rom me!hanol in !he reacton CHH M HCH ( H+ A sin%le@"ass con3ersion o# '/./0 is achie3ed in !he reac!or. -he me!hanol in !he
reac!or "roduc!
is se"ara!ed
#rom !he
#ormaldehde and hdro%en in a mult"le@uni! "rocess. -he "roducton ra!e o# #ormaldehde is ?//./ k%*h. a8 Calcula!e !he reuired #eed ra!e o# me!hanol !o !he "rocess 7kmol*h8 i# !here is no reccle. b8 ;u""ose !he reco3ered me!hanol is reccled !o !he reac!or and !he sin%le "ass con3ersion remains '/0. De!ermine !he reuired #resh #eed ra!e o# me!hanol 7kmol*h8 and !he ra!es 7kmol*h8 a! 4hich me!hanol en!ers and lea3es !he reac!or. -iCl 5 can be #ormed b reactn% t!anium dio$ide 7-i+8 4i!h hdrochloric acid. -i + is a3ailable as an ore con!ainin% 12 0 -i + and ++ 0 iner!s. -he HCl is a3ailable as 56 4!0 soluton 7!he balance is 4a!er8. -he "er "ass con3ersion o# -i + is 16 0. -he HCl is #ed in!o !he reac!or in +/ 0 e$cess based on !he reacton. ure unreac!ed -i+ is reccled back !o mi$ 4i!h !he -i + #eed. N
N-i+ ( 5 HCl M -iCl 5 ( + H+
For k% o# -iCl5 "roduced, de!ermine: a. !he k% o# -i+ ore #ed. b. !he k% o# 56 4! 0 HCl soluton #ed. c. !he rato o# reccle s!ream !o #resh -i + ore 7in k%8. 7K : -i+ 1?.?O HCl '.51O -iCl5 2?.18
B:
