2.3 Market :
According According to CMAI (2007), global butadiene butadiene demand is expected to grow at just under 3!"#$ear t%roug% 20&2, slig%tl$ abo'e t%e a'erage o 32"#$ear growt% o t%e past i'e $ears emand in India will be t%e largest, growing nearl$ &!"#$ear or t%e next i'e $ears $ears eman emand d in Asia is expec expecte ted d to excee exceed d !"#$ !"#$ear ear,, alt%ou alt%oug% g% demand demand in som somee countries, primaril$ C%ina, will be at more t%an &0", anal$sts sa$ emand in *ort% America and +estern urope is expected to rise at less t%an &" Most o t%e capacit$ will be added in Asia, particularl$ C%ina, w%ic% will account or nearl$ 7!" o new capacit$, added beore 20&2 -perating rates in Asia are expected to be strong at .!"/0", w%ile operating op erating rates in urope will be %ig%est, at about 0", anal$sts sa$ -perating rates in *ort% America are expected to %o'er in t%e 70" range, t%e$ sa$ 1able 23 s%ows t%e butadiene producer and production rate in Asia *otice t%at in Mala$sia, t%ere is onl$ &00,000 mt #$ear production totall$
Country
C%ina
India
apan
@orea
Producers
angi 4etroc%emical C*--C 5%ell 4etroc%emicals6 Maoming 4etroc%emical ilin C%emical 8ilu 4etroc%emical 9an%ou 4etroc%emical 5%ang%ai 4etroc%emical ans%an 4etroc%emical -t%ers 1otal :eliance Industries -t%ers 1otal apan 5$nt%etic :ubber C%iba
a$ama ing Centre @orea @um%o 4etroc%emical
Production Rate (in thousands of MT./year) &. ! &! ! &! 0 &6 0 &3 0 &2 0 &2 0 &&3 3 ! & ! 0. &! 0 &7 2 32 2 2; . &7 7 &!0 &6 0 &3 0 &0 ! 70 & 0 60 2& . 20 !
Mala$sia 5ingapore 1aiwan
1%ailand
9? C%emical 9otte aesan 4etroc%emical 5amsung 4etroc%emicals 9? aesan 4etroc%emical 5@ Corp 5@ nerg$ 1otal 1itan 4etc%em 1otal 1otal ormosa 4etroc%emical C%inese 4etroleum 1otal o> 5$nt%etics I:4C! 1otal Average:
&6 ! &0 . 72 72 & 0 &. &0 0 &0 0 ;0 ;0 37 3 &7 3 !6 ; &6 0 ;! 20 ! !"."#$%&
2.! 'utadiene Manufacturing Process nforation :
&) 5team Crac>ing Crac>ing o 4arainic 4arainic $drocarbonsB $drocarbonsB In t%is process, process, butadiene butadiene is a co/ product product in t%e manuacture o et%$lene (t%e et%$lene co/product process) 2) Catal$tic Catal$tic e%$drogenati e%$drogenation on o n/
ac% o t%ese processes produces a stream commonl$ reerred to as crude butadiene t%at is ric% in &,3/butadiene
2.!. 'utadiene Production *ia +tea Cracking of Paraffinic ,ydrocar-ons
1%e steam crac>ing process is reported to be t%e predominant met%od o t%e t%ree processes o production, prod uction, accounting or o r greater t%an &" o t%e worldEs wor ldEs butadiene suppl$ igure depicts a low c%art or a t$pical oleins plant +%ile t%is does not represent an$ particular plant, and t%ere are certainl$ man$ 'ariations among oleins plants, t%is representation represen tation will pro'ide t%e reader read er wit% a general understanding under standing o t%e process
1%e indicated eedstoc>s (et%ane, propane, butane, nap%t%a and gas oil) are ed to a p$rol$sis (steam crac>ing) urnace w%ere t%e$ are combined wit% steam and %eated to temperatures between approximatel$ &6!0/&!2! F (70/.30 FC) +it%in t%is temperature range, t%e eedstoc> molecules Gcrac>G to produce %$drogen, et%$lene, prop$lene, butadiene, benene, toluene and ot%er important oleins plant co/products Ater t%e p$rol$sis reaction is Huenc%ed, t%e rest o t%e plant separates t%e desired products into streams t%at meet t%e 'arious product speciications 4rocess steps include distillation, compression, process gas dr$ing, %$drogenation (o acet$lenes), and %eat transer 1%e ocus o t%is re'iew is &,3/butadiene%owe'er, since butadiene is created in t%e oleins plant p$rol$sis urnace, and is present in t%e crude butadiene product stream at concentrations up to approximatel$ 7! wt", t%e oleins plant process and t%e crude butadiene stream are addressed in t%is publication to a limited degree
1%e low pat% o t%e C6 components (including butadiene) are indicated b$ bold JredK lines
+%ile some oleins plant designs will accommodate an$ o t%e listed eedstoc>s, man$ oleins plants process onl$ *atural ?as 9iHuids (*?9s) suc% as et%ane, propane and sometimes butane 1%e mix o eedstoc>s, t%e conditions at w%ic% t%e eedstoc>s are crac>ed, and t%e p%$sical plant design, ultimatel$ determine t%e amount o eac% product produced, and or some o t%e streams, t%e c%emical composition o t%e stream
2.!.2 'utadiene Production via Cataytic ehydrogenationof n0'utane and n0 'utene (the ,oudry 1rocess)
1%e catal$tic de%$drogenation o n/butane is a two/step process initiall$ going rom n/ butane to n/butenes and t%en to butadiene
In t%e oudr$ process, n/butane is de%$drogenated o'er c%romium#alumina catal$sts 1%e reactors normall$ operate at &2/&! centimeters g absolute pressure and approximatel$ &&00/&2;0 F (;00/;.0 FC) 1%ree or more reactors can be used to simulate continuous operationB w%ile t%e irst reactor is on/line, t%e second is being regenerated, and t%e t%ird is being purged prior to regeneration :esidence time or eed
in t%e reactor is approximatel$ !/&! minutes As t%e endot%ermic reaction proceeds, t%e temperature o t%e catal$st bed decreases and a small amount o co>e is deposited In t%e regeneration c$cle, t%is co>e is burned wit% pre%eated air, w%ic% can suppl$ essentiall$ all o t%e %eat reHuired to bring t%e reactor up to t%e desired reaction temperature
1%e reactor eluent goes directl$ to a Huenc% tower, w%ere it is cooled 1%is stream is compressed beore eeding an absorber#stripper s$stem, w%ere a C6 concentrate is produced to be ed to a butadiene extraction s$stem or t%e reco'er$ o %ig% purit$ butadiene
2.!.3 'utadiene Production via idative ehydrogenation of n0'utenes (the o0 or 040 1rocess)
-xidati'e de%$drogenation o n/butenes %as replaced man$ older processes or commercial (on/purpose) production o butadiene 5e'eral processes and man$ catal$st s$stems %a'e been de'eloped or t%e ox$de%$drogenation o eit%er n/butane or o n/ butene eedstoc>s in t%is process ma$ not be practical
In general, in an ox$de%$drogenation process, a mixture o n/butenes, air and steam is passed o'er a catal$st bed generall$ at low pressure and approximatel$ 30/&&&0 F (!00/;00 FC) 1%e %eat rom t%e exot%ermic reaction can be remo'ed b$ circulating molten %eat transer salt, or b$ using t%e stream externall$ or steam generation An alternate met%od is to add steam to t%e eed to act as a %eat sin> 1%e %eat can t%en be reco'ered rom t%e reactor eluent:eaction $ields and selecti'es can range rom 70/ 0", ma>ing it unnecessar$ to reco'er and rec$cle eedstoc>
'utadiene Production via idative ehydrogenation
In t%e -xo/ process s%own in igure, a mixture o air, steam, and n/butenes is passed o'er t%e de%$drogenation catal$st in a continuous process 1%e air eed rate is suc% t%at an ox$gen#butene molar ratio o approximatel$ 0!! is maintained, and t%e ox$gen is totall$ consumed A steam to butene ratio o &0B& %as been reported as necessar$ to absorb t%e %eat o reaction and to limit t%e temperature rise
1%e reactor eluent is cooled and t%e C6 components are reco'ered in an absorber#degasser# stripper column combination 1%e lean oil lows rom t%e bottom o t%e stripper bac> to t%e absorber, wit% a small amount passing t%roug% a sol'ent puriication area Crude butadiene is stripped rom t%e oil, reco'ered in t%e o'er%ead o t%e stripper, t%en it is sent to a puriication s$stem to reco'er t%e butadiene product
2.!.! Concusion of Product +eection :
Comparisons or all our products %a'e been tabulated in 1able 26
Increasing mar>et demand especiall$ in Asia region emand in Asia will grow at a more rapid rate, at !" #$ear, alt%oug% demand in some countries, particularl$ C%ina, will be at more t%an &0"#$ear (CMAI, 2007)
•
•
•
•
ig% mar>et pricing o L5 0;6#lb w%ic% will gi'e %ig%er proit -nl$ one competitor in Mala$sia, w%ic% is 1itan 4etc%em (M) 5dn <%d *earb$ neig%bor, 5ingapore is onl$ producing ;0mt#$r Aiming to be t%e major butadiene supplier in Asia
Ta-e B Comparison between potential
Poyiso-utyene
Maeic Anhydride
Pro1yene ide
'utadiene
Mar>et
&30 per pound
0;3 per pound
0;6 per pound
0;6 per pound
pricing Complexit$
(&;/200&) Copol$meriation
(2007) -xidation o
(&!/2000) 2 routes
(200;) Catal$tic
o t%e
o isobut$lene
aromatic
/c%loro%$drin
de%$drogenation
compound
/indirect
o normal butane
Mature mar>et
oxidation 4rice stable and
4resent mar>et
rising demand
irmed and
reactions 5trengt%s
1ires,tubes t%e largest end user
+ea>nesses
accounting or 7!/
increasing
.0" total
ig% mar>et
consumption
potential
ortunes tied
?rowt% slowed
emand dri'en b$
ea'il$ relied on
%ea'il$ to tires
down and *o
automoti'e,
automoti'e
industr$
growt%
%ousing and
industr$
agriculture
construction
c%emical
mar>et
and oil additi'es 1%e process w%ic% is %ere described in t%e project among t%ese t%ree processes is t%e production o t%e n/
2.& C5C6PT7A8 6+95 A5A8++
1%e ierarc%ical ecomposition Approac% suggested b$ ouglas (&..) is consisted o 3 %ierarc%$ o decisions, w%ic% areB
9e'el &B
2.&.
'ATC, vs. C5T577+
Continuous processes are designed so t%at e'er$ unit will operate continuousl$ or close to a $ear at almost constant conditions beore t%e plant s%ut down or maintenance -n t%e ot%er %and, batc% processes normall$ contain se'eral units t%at are designed to be started and stopped reHuentl$ uring a normal batc% operating c$cle, t%e units are illed wit% material and perorm t%eir desired unction or a speciied period Ater t%at, t%e units will be s%ut down, drained and cleaned beore t%e c$cle is repeated (ouglas M, &..) According to ouglas (&..), t%ere are a ew criteria t%at needed to be considered w%en selecting t%e t$pe o process, w%ic% areB
. Production rates:
4lant t%at %as a capacit$ t%at is greater t%an &0 x &0; Ib#$r is usuall$ continuous In contrast, i t%e plantNs capacit$ is less t%an & x &0; Ib#$r, t%en batc% process will be c%osen
It is 'er$ diicult to build continuous processes w%en a low capacit$ o slurries must be %andled 1%is is because it is 'er$ %ard to pump slurries at low low rate wit%out %a'ing t%e solid settling out o t%e suspension and plugging t%e eHuipment problem 5ome materials tend to oul t%e eHuipment reHuentl$ t%at t%e eHuipment must be s%ut down and cleaned 'er$ oten ence, batc% process is suitable or t%is >ind o process instead o continuous
A decision to puri$ t%e eeds beore t%e$ enter t%e process is eHui'alent to a decision to design a preprocess puriication s$stem 5ome design guidelines to be considered are as ollows (ouglas, &..)B i
I a eed impurit$ is not inert and is present in signiicant Huantities, remo'e it -t%erwise it will lead to raw/material losses, and usuall$ a muc% complicated separation s$stem is reHuired to reco'er t%e additional b$/products
ii I a eed impurit$ is present in a gas eed, as a irst guess process t%e impurit$ iii I a eed impurit$ in a liHuid eed stream is also a b$/product or a product component, usuall$ it is better to eed t%e process t%roug% t%e separation s$stem
i' I a eed impurit$ is present in large amounts, remo'e it ' I a eed impurit$ is present as an aeotrope wit% a reactant, oten it is better to process t%e impurit$ 'i I a eed impurit$ is inert but is easier to separate rom t%e product t%an t%e eed, it is better to process t%e impurit$ 'ii I a eed impurit$ is a catal$st poison, remo'e it
1able s%ows t%e composition o t%e component in eed 1%e main component t%at is to be used in butadiene production is n/butane owe'er, t%e amount o isobutane in t%e stream is large (33 mole ") I isobutane is not separated rom t%e eed and is processed, additional b$ product mig%t be produced and t%us complicated t%e separation process downstream 1%is will imposed additional cost (capital and operating) to t%e plant ence, wit% reerence to guideline i and i', t%e team decided to puri$ t%e stream irst beore entering to t%e reactor
Ta-e : Composition of the Components in the Feed Co1onent
;orua
Moe <
4ropane
C3.
0
i/
C6&0
2!
n/
C6&0
722
-t%er $drocarbon
C!O
&0
;igure : 4uriication o t%e eed
igure s%ows t%e sc%ematic diagram o t%e eed puriication section istillation column is used to separate t%e impurities rom t%e eed As s%own in t%e diagram, n/butane will be wit%drew as side draw product, w%ile isobutane and propane will be wit%drew rom t%e distillation column as t%e top product and C!O as bottom product 1o con'ert n/butane to butadiene, two stages o de%$drogenation reaction are in'ol'ed (non/oxidati'e and oxidati'e de%$drogenation) 1%e b$ product o t%e processes are %$drogen (2), carbon monoxide (C-), carbon dioxide (C-2), s%ort c%ain %$drocarbon (C&/C3) and steam (2-) igure 63 s%ows t%e sc%ematic diagram o two stages o de%$drogenation process -nl$ approximatel$ 33" o n/butane will be con'erted to butadiene ence t%e unreacted n/butane will be rec$cled
;igure : 1wo 5tages e%$drogenation o n/butane
5ince onl$ approximatel$ 33" o n/butane will be con'erted to butadiene, t%e unreacted n/butane will be rec$cled ater separated o t%e product stream It is impossible to ac%ie'e s%arp separation in t%e separation process ence, t%e rec$cle stream will consist o low raction o impurities ence, part o t%e rec$cle stream will be purged to a'oid accumulation o t%e impurities in t%e process stream
2.# n1ut ut1ut +tructure B
2.% R6CC86 / R6ACTR +5T,6++
?ood reactor perormance is o paramount importance in determining t%e economic 'iabilit$ o t%e o'erall design and undamentall$ important to t%e en'ironmental impact
o t%e process (5mit%, 200!) 1%ereore, issues to be addressed or a good reactor design s%ould include & :eactor t$pe 2 Catal$st 3 5ie 6 -perating Conditions (1emperature and 4ressure) ! 4%ase ; eed Conditions (Concentration and temperature) At earl$ stages in design, a >inetic model normall$ is not a'ailable 1%us, material balance calculations s%ould be based on a correlation o t%e product distribution (ouglas, &.) 1%is t$pe o >inetic anal$sis is 'er$ crude but in most cases t%e reactor cost is not nearl$ as important as t%e product distribution costs
2.%. Reactor +eection
1%e selection o reactor is cruciall$ important in order to ma>e sure t%at t%e eed operates at its maximum or single reaction, t%e %ig%est rate o reaction is maintained b$ t%e %ig%est concentration o eed (5mit%, 200!)
5ince t%e reaction is carried out in gas p%ase o'er a selecti'e catal$st, t%e options or t$pe o reactor selection or t%is t$pe o reaction are ixed/bed catal$tic reactor and luidied bed reactor 1%e structure o ixed bed catal$tic reactor is similar to a s%ell and tube %eat exc%anger It is a tubular reactor t%at is pac>ed wit% solid catal$st particles It gi'es t%e %ig%est con'ersion per weig%t o catal$st o an$ catal$tic reactor It is suitable to be used or %ig% pressure reaction w%ere smaller diameter c$linder 'essels are used to allow usage o t%inner 'essel walls ixed bed catal$tic reactor is also suitable or process t%at uses catal$st wit% a long lie time owe'er, it %as diicult$ wit%
temperature control because %eat loads 'ar$ t%roug% t%e bed 1emperature in t%e catal$st mig%t become locall$ excessi'e, w%ic% ma$ lead to undesired product and catal$st deacti'ation 1%e catal$st is usuall$ troublesome to replace too
-n t%e ot%er %and, luidied bed reactor is designed to be operated in a well mixed condition between t%e gas p%ase reactant and catal$st, w%ic% result in an e'en temperature distribution t%roug%out t%e bed 5ince t%e temperature is relati'el$ uniorm t%roug%out t%e reactor, t%e possibilit$ o %a'ing %ot spots n t%e reactor can be eliminated 1%e %eat transer rate is %ig% due to t%e rapid motion o t%e catal$st It can also %andle large amounts o eed and solids and %as good temperature control -ne o t%e disad'antages o luidied bed reactor is %ig% operating cost urt%ermore, t%e attrition o catal$st can cause generation o catal$st ines w%ic% could be carried o'er and lost in t%e s$stem 1%is ma$ cause ouling in t%e pipelines or eHuipment downstream ence, luidied bed reactor is 4reerable or gas/solid non/catal$tic reactions 1%e ad'antages and disad'antages o bot% t$pes o reactors are summaried in 1able
Ta-e : Ad'antages and isad'antages o 4ac>ed
Reactor
;ied 'ed Cataytic Reactor •
It gi'es t%e %ig%est
;uidi=ed 'ed Reactor •
con'ersion per weig%t o catal$st o an$ catal$tic reactor •
Ad'antages
to rapid motion o catal$st •
Lsed or %ig% pressure
o t%inner 'essel walls
1%e temperature is relati'el$ uniorm t%roug%out t%e
reaction w%ere smaller diameter c$linder 'essels is used to allow usage
ig% %eat transer due
catal$st, t%us a'oiding %ot spots •
Can %andle large amounts o eed and solids and %as good temperature control
iicult to control t%e
•
temperature because %eat loads 'ar$
and catal$st regeneration
t%roug% t%e bed
eHuipment
1emperature in t%e catal$st
•
isad'antages
ig% cost o t%e reactor
•
•
Attrition o catal$st
becomes locall$ excessi'e, w%ic% ma$
can cause generation o catal$st
lead to undesired product and catal$st
ines w%ic% could be carried o'er
deacti'ation
and lost in t%e s$stem, and ma$ cause ouling in pipelines and
1%e catal$st is usuall$
•
eHuipment downstream
troublesome to replace C%anneling o t%e gas low
•
•
occurs, resulting in ineecti'e use o
4reerable or gas/solid non/catal$tic reactions
parts o t%e reactor bed
Ater comparing bot% t$pes o reactor, tubular ixed/bed catal$tic reactor is c%osen or all t%ree reactors in'ol'e in t%e process 1%is is due to t%eB a
lower capital and operating cost •
1%e reactions in'ol'ed in t%e butadiene production are reHuired to be operated in %ig% pressure condition
•
1%e reHuired 'olume or tubular ixed bed catal$tic reactor is smaller compared to luidied bed reactor or %ig% pressure operation, and t%us lower capital cost
•
1%e operating cost or luidied bed reactor is 'er$ %ig% because it is more diicult to maintain t%e gas p%ase reactant and catal$st to be in t%e well mixed condition i it is operated in %ig% pressure
b
less losses in catal$st
•
1%ere will be losses in catal$st i luidied bed reactor is selected
•
1%e losses in catal$st are resulted romB •
catal$st will settle at t%e bottom o t%e reactor i it is not well mixed wit% t%e gas p%ase reactant
•
catal$st ine mig%t be generated during t%e operation o t%e reactor w%en t%e catal$st %it on t%e wall o t%e reactor or t%roug% attrition 1%e catal$st ine will
be broug%t to t%e downstream o t%e process w%en toget%er wit% t%e product stream c
lower maintenance cost •
I luidied bed reactor is selected, t%e catal$st t%at settle at t%e bottom o t%e reactor will oul and plug t%e reactor w%ile t%e generated catal$st ine will cause ouling in t%e pipeline and eHuipment downstream
•
4lant mig%t need to be s%ut down oten or maintenance
2.$ +6PARAT5 +TR7CT7R6
1%e core reaction in butadiene production is t%e de%$drogenation using n/butane as t%e reactant owe'er, t%e eed stream contains signiicant amount o i/butane w%ic% is up to 33" 1%us, in order to increase $ield, we need to con'ert i/butane into n/butane 1%e con'ersion is done in t%e Isomeriation :eactor 1%e deisobutanier column in pretreatment section emplo$s side draws to $ield puriied n/butane 1%e n/butane stream is drawn as a 'apor side product a ew tra$s abo'e t%e bottom, lea'ing a small %ea'$ end stream w%ic% is onl$ about &" o t%e eed stream to be t%e bottom product 1%us, t%e s$stem consists o two prominent products and we can assume t%at t%e small stream does not exist 1%e initial assumption or distillation columns is to %a'e 002 mole percent o lig%t >e$ component in bottom and 00& mole percent o %ea'$ >e$ component in t%e o'er%ead product Also, we assume t%at all t%e component lig%ter t%an t%e lig%t >e$ lea'e wit% o'er%ead and t%at all components %ea'ier t%an t%e %ea'$ >e$ are ta>en at t%e bottoms 2.$. esign of 6tractive istiation Coun :
According to 5eader (&.), extracti'e distillation is a partial 'aporiation process in t%e presence o a miscible, %ig%/boiling, non/'olatile mass separation agent, normall$ called t%e solvent, w%ic% is added to an aeotropic or non/aeotropic eed mixture to alter t%e 'olatilities o t%e >e$ components wit%out t%e ormation o an$ additional aeotropes
2.$.2 +ovent seection:
5ince t%e sol'ent is t%e %eart o extracti'e distillation, more attention s%ould be paid on t%e selection o potential sol'ents 1%e ainit$ o %$drocarbon to polar sol'ent depends directl$ on t%eir degree o un/saturation A %ig%l$ unsaturated %$drocarbon is more soluble in a polar sol'ent, and t%e sol'ent decreases t%e 'olatilit$ o t%e %$drocarbon , se'eral eatures are essentialB & 1%e sol'ent must be c%osen to aect t%e liHuid/p%ase be%a'ior o t%e >e$ components dierentl$ ot%erwise no en%ancement in separabilit$ will occur 2 1%e sol'ent must be %ig%er boiling t%an t%e >e$ components o t%e separation and must be relati'el$ non'olatile in t%e extracti'e column, in order to remain largel$ in t%e liHuid p%ase 3 1%e sol'ent s%ould not orm additional aeotropes wit% t%e components in t%e mixture to be separated 6 1%e extracti'e column must be a double/eed column, wit% t%e sol'ent eed abo'e t%e primar$ eed t%e column must %a'e an extracti'e section rom LllmanNs %andboo> (&.!), t%ere are i'e sol'ents t%at are commonl$ used in industr$B a n/met%$l/2/p$rrolidone (*M4), b dimet%$lormamide (M) c imet%$lacetamide (MAC) d Acetonitrile (AC*) e urural - all possible sol'ents t%at can be used or t%e separation o butadiene/butane mixture we %a'e c%osen dimet%$lormamide (M) M is recommended as a potential entrainer because it gi'es great alteration in relati'e 'olatilit$ 1%is in turn will ma>e t%e separation easier and c%eaper, as t%e utilities and tra$s reHuired are lesser 'en t%oug% *M4 gi'es greater 'alue, it costs almost twice t%e M
C,APT6R 3: PRC6++ 6+CRPT5
Process escri1tion
In t%is project, butadiene is produced in continuous process ere t%e &,3/butadiene is produced b$ oxidati'e de%$drogenation reaction
3. Pre1rocess Purification > eiso-utani=er :
E-102
6
C-101
4
E-101
3
;igure : 4reprocess 4uriication 5ection
1%e main objecti'e o t%is pre/treatment unit is to extract n/butane rom t%e eed 1%e extracted n/butane will be used as t%e reactant or t%e de%$drogenation process in order to produce butadiene
1%e eed omposition is as ollows B
Ta-e : eed Composition Co1onent
;orua
Moe <
4ropane
C3.
0
i/
C6&0
2!0
n/
C6&0
722
-t%er $drocarbon
C!O
&0
rom t%e table, it can be seen t%at t%e eed also contains signiicant amount o i/butane w%ic% is 2!0 " In order to ull$ utilie t%e eed, t%e separated i/butane will be sent to isomeriation section to undergo t%e isomeriation process t%at will con'ert i/butane to n/butane
1%e distillation column, C/&0& will reco'er i/butane as t%e top product 1%e o'er%ead product o t%e column also consists o signiicant amount o n/butane or t%e sa>e o purit$, t%e o'er%ead product will enter t%e 'apor reco'er$ s$stem w%ic% is t%e condenser (/&02) 1%e operating temperature and pressure o /&02 are 607&oC and 300 >4a 1%e condensed product w%ic% is mainl$ n/butane will be rec$cled bac> to C/ &0& w%ile t%e 'apor product w%ic% is mainl$ i/butane will be sent to t%e Al>$lation 5ection */butane is extracted as t%e side product 1%is n/butane will enter t%e :eaction 5ection to undergo t%e de%$drogenation process 1%e bottom product o t%is column consists o t%e %ea'ier product w%ic% is t%e condensate (C!O) toget%er wit% considerable amount o n/butane 1%e bottom stream o column will t%en enter t%e reboiler (/&0&) to reco'er t%e n/butane 3.2 ehydrogenation +ection
1%e t%ird section o t%e plant is t%e de%$drogenation unit 1%e main objecti'e o t%e unit is to con'ert t%e n/butane to t%e product desired,
;igure : ehydrogenation +ection
1%e process gas rom 5ection &, t%e preprocess unit enters t%e urnace (30&) at 622oC 1%e urnace will %eat up t%e process gas up to ;00oC 1%e %eated process gas will enter t%e e%$drogenation :eactor (:30&) w%ere t%e n/butane will be con'erted in to butenes $drogen and ot%er b$product suc% as C& P C3 will also orm1%e e%$drogenation :eactor (:30&) is a ixed bed tubular reactor operating at temperature o !00oC and pressure o 3 bar 1%e reaction is an exot%ermic reaction and t%e temperature is maintained using molten salt at t%e s%ell side o t%e reactor 1%e catal$st used in t%e reactor is t%e Pt?.3 +n?.#Cs?.&@ ?.& 8a3.? w%ic% gi'es t%e con'ersion o 32 " and selecti'it$ o ;" 1%e butenes rom :30& will be cooled down rom ;00oC to 620oC b$ e%$drogenation Inter/cooler (30&) beore urt%er supplied to -xidati'e e%$drogenation :eactor (:302) 1%e :302 is also a ixed bed tubular reactor and is operating at temperature o 330oC and pressure o 3 bar
