introduction 6

5/28/2018 Introduction 6

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Design of a Process for Production of Isopropyl Alcohol byHydration of Propylene in a Catalytic Distillation Column

Yan Xu, Karl T Chuang and Alan ! "anger

Department of Chemical and Materials Engineering

University of AlbertaEdmonton, AlbertaCanada T6G 2G6

A#"T!ACT

A novel process flo sheet has been developed for the application of catalytic distillation

technology to the prod!ction of isopropyl alcohol "#$A% by hydration of propylene& 'peration

of the catalytic distillation col!mn has been sim!lated !sing both e(!ilibri!m)stage and

e(!ilibri!m)reaction models& *igh p!rity #$A "++&+vol% is prod!ced as a li(!id prod!ct


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I$T!%D&CTI%$

Isopropyl Alcohol Production

#sopropyl alcohol "#$A% has been called the first modern synthetic petrochemical&

.eca!se #$A has physical characteristics compatible ith those of alcohol, ater, and

hydrocarbons, it is a versatile and ine/pensive solvent !sed idely in the chemical and

cosmetics ind!stries& Unli0e ethanol, #$A is s!b1ect to fe government reg!lations, and no

special ta/es are levied on cons!mption of #$A& #$A is !sed as feedstoc0 for the man!fact!re

of acetone and other compo!nds& #$A is !sed idely as an antiseptic and disinfectant for

home, hospital, and ind!stry applications "*ancoc0-, roschit32%&

4everal methods are available for man!fact!re of #$A& The methods !sed most idely are

direct hydration and indirect hydration of propylene "roschit32%& .oth processes !se

propylene and ater as ra materials&

# di t h d ti i b d t t i hi h t i f d d th


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#ndirect hydration is based on a to stage process in hich an ester is formed and then

Etherification5

OCHCHOHCHOHCH 2222 %%""%"2 +

There are three propylene direct hydration processes in commercial operation5 vapor)

phase hydration over a fi/ed)bed catalyst "roschit32%< mi/ed vapor)li(!id)phase hydration

!sing strongly acidic proton )e/change resin catalyst "=eier and >eollner %< and li(!id)phase

hydration in the presence of a homogeneo!s catalyst "'no!e et al&?

%&

The p!rity of #$A prod!ct re(!ired depends on the intended application& The @t #$A

a3eotrope prod!ced issold as s!ch or is dehydrated by a3eotropic distillation to prod!ce an

anhydro!s prod!ct& Minor imp!rities are removed and the odor of #$A is improved by !se of

either intense a(!eo!s e/tractive distillation, or post)treatment by a fi/ed)bed absorption

process !sing activated carbon, molec!lar sieves or metals and ;or metal o/ides of Gro!p #.,

B#. and B### of the $eriodic Table "4avini8%& Essence grade #$A is prod!ced by distillation of

dehydrated #$A)ater a3eotrope in nonferro!s e(!ipment&

A typical process scheme for direct hydration of propylene is shon in ig!re -& The

principal difference beteen the direct and indirect processes is that m!ch higher press!re is

"2%


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Catalytic Distillation

Catalytic distillation "CD% comprises the processes of heterogeneo!s catalytic reaction

and m!ltistage distillation carried o!t sim!ltaneo!sly in a single vessel& A CD col!mn

replaces the separate fi/ed)bed reactor and a series of distillation col!mns, thereby red!cing

the n!mber of process vessels and materials transfer and control e(!ipments re(!ired& Th!s,

capital costs are red!ced "DeGarmo et al&6%&

CD is a viable option hen the temperat!re and press!re of a process are s!ch that the

rate of reaction is s!fficiently high !nder conditions for separation of prod!cts by distillation&

E(!ilibri!m)limited reactions are e/cellent candidates for catalytic distillation< by

contin!o!sly separating prod!cts from reactants hile the reaction is in progress, the reaction

can proceed to a m!ch higher level of conversion than is attainable !sing a conventional

process "oc0, 4hoema0er and :ones @%&

C!rrently, the largest !sers of reactive distillation technology are f!el)ether prod!cing

!nits& A variety of ethers can be prod!ced by reacting olefins having fo!r, five, or si/ carbon


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"2% *ydration can ta0e place in the li(!id phase< catalyst pellets ill remain completely

etted&

"% The reaction ill be cond!cted at a temperat!re and press!re e(!ivalent to the boiling

point of the li(!id prod!ct< distillation and reaction ill be carried o!t sim!ltaneo!sly in the

same col!mn&

"?% *ydration is e/othermic< the heat of reaction ill provide energy re(!ired for

separation of the reaction mi/t!re by distillation&

"8% D!rable heterogeneo!s hydration catalysts ith s!itable physical properties are

commercially available "!o and Chen-9, 4onnemans --, 4onnemans -2, 'dios, et al&-%&

"6% #n a CD hydrolysis process, ater ill be contin!o!sly cons!med by fresh propylene,

and an #$A)rich stream ill be contin!o!sly prod!ced& *ence, the prod!ct stream ill have a

higher #$A content than prod!ct streams !sing conventional processes&

A ma1or advantage of catalytic distillation over conventional fi/ed)bed reactors is the

red!ction in capital investment "=g and empel -?, $odrebarac and =g +, oc0 et al&%& The

chemical reaction and distillation are carried o!t in the same vessel, th!s simplifying the


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'%D() %* A CD P!%C("" *%! IPA P!%D&CTI%$

4im!lation has become an essential component of reactive distillation process design, and

is even more important for CD process design than for design of conventional distillation

systems& The interaction beteen sim!ltaneo!s reaction and distillation processes increases

the comple/ity of CD systems compared ith systems comprising conventional reactors

folloed by distillation systems& Modeling methods are of even greater importance hen

there is no available satisfactory shortc!t or empirical methods for the determination of 0ey

parameters "$ilavachi-8%& eliable sim!lation softare allos a ne CD process to be

modeled !sing 0non thermodynamic and 0inetic data& Bal!es for 0ey design parameters can

be identified ith a high degree of confidence& 4im!lation can also be applied to an e/isting

process to st!dy the effect of varying 0ey parameters, and thereby provide g!idelines for

f!rther optimi3ation of the process&

"imulation #asis


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ass!mption introd!ces no significant error for steady)state sim!lations& #n the first stage of the

development of the model, propylene direct hydration to #$A as the only reaction ta0en into

acco!nt, since the propylene hydration catalyst "3eolite or proton)e/changed resin% has high

selectivity toard the desired prod!ct "+8t Eg!chi, et al& -6% in the operating temperat!re

range& *oever, no catalyst has yet been developed that selectively cataly3es conversion of

propylene to #$A itho!t also forming D#$E& Therefore the present model incl!des #$A and

D#$E as e(!ilibri!m prod!cts of the hydration reaction&

The al0ene)alcohol)ater)ether system is non)ideal& Conse(!ently, the selection of

physical property ro!tines is of great importance& The U=#AC method has been !sed

s!ccessf!lly to predict li(!id phase activity coefficients and e(!ilibri!m constant e/pressions

of similar non)ideal systems in sim!lation of ET.E, ME.E, and DAA "diacetone alcohol%

prod!ction processes "$odrebarac et al&-, 4neesby et al&-@%& U=#AC also has been !sed to

acc!rately model the vapor)li(!id behavior of the #$A)ater system& The U=#AC method

therefore has been shon to be s!itable for the calc!lation of the li(!id phase activity

coefficients and e(!ilibri!m constants re(!ired for the present st!dy& The edlich)ong


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CD process by !sing Aspen$l!s& adrac distillation !nit b!ilt into Aspen$l!s as !sed to

obtain the data reported herein&

Catalytic Distillation Column

The core of the CD process is the catalytic distillation col!mn "ig!res 2 and %& A

col!mn in hich propylene hydration is to be performed has three ma1or sections& The

reaction occ!rs over one or more catalyst beds mo!nted in the middle section of the col!mn&

ectification of the volatile components of the reaction mi/t!re occ!rs in the top section&

Fi(!id prod!cts are recovered from the bottom of a loer stripping section& *erein e ill

describe CD col!mns having either a single catalyst bed "ig!re 2% or d!al catalyst beds

"ig!re %& eaction of propylene hydration to #$A and #$A etherification to D#$E over the

catalyst in the middle section proceed sim!ltaneo!sly ith distillation in the rectifying and

enriching sections of the col!mn& Unreacted volatiles rise from the reaction 3one to the

rectifying section and are separated from heavier components before being removed from the


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"imulation !esults

irstly, for each col!mn config!ration, the effect of varying the press!re and temperat!re

on the process as determined& Distillate flo rate and feed ratio ere ad1!sted to obtain

optim!m high p!rity prod!ct& Then the n!mber of plates in the rectifying 3one, above the

catalyst bed"s%, and in the stripping 3one, belo the catalyst bed"s%, ere varied

independently, and the impact of the location of either a single catalyst bed or d!al catalyst

beds as systematically e/amined& The optim!m config!ration has been determined

>e ill sho that the optim!m config!ration is a col!mn having d!al catalyst beds, an

!pper rectifying section having 2 plates, and a loer stripping section having 2- plates& The

effect of changing each of the 0ey variables ill be described&

K(Y +A!IA#)("


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%perating Pressure and Temperature

#n conventional distillation, the press!re range !sed is determined by the condenser

coolant and reboiler heating media temperat!res& #n a CD process, the selection of operating

press!re m!st ta0e into acco!nt the effect of press!re on the reaction 3one temperat!re, hich

depends on the relative volatility of reactants, prod!cts and a3eotropes "DeGarmo et al&6%&

#n a CD col!mn, the reaction 3one temperat!re is determined by the boiling point of the

li(!id mi/t!re in the catalyst bed, hich in t!rn is determined by the composition of the li(!id

and the operating press!re& *oever, beca!se separation and reaction occ!r sim!ltaneo!sly in

the col!mn, the composition of the li(!id phase is a f!nction of temperat!re and ratio of feed

rates& or the present propylene)ater)#$A)D#$E system, the reaction 3one temperat!re

increases ith increase in press!re& The propylene hydration reaction and #$A etherification

are highly e/othermic& $ropylene conversion decreases ith an increase in reaction 3one

temperat!re& Conse(!ently, the content of #$A in the reaction mi/t!re is red!ced ith an

increase in col!mn press!re& *oever, the reaction rate increases ith increasing


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The relative volatility of reactants and prod!cts declines ith increasing press!re& The

change in the relative volatility ith press!re is grad!al and small, and does not significantly

affect reaction and separation&

The loer limit of the operating press!re is set at conditions, hich allo a reasonable

reaction rate and the !se of ater as coolant in the condenser& The operating press!re of the

CD col!mn as varied in the range of 9&-)8 M$a& The coolant inlet temperat!re, reaction

3one temperat!re, conversions of propylene and ater, and prod!ct p!rity have been !sed to

determine the optim!m operating press!re range& or the present model, it has been fo!nd that

the optim!m press!re for operation of a d!al catalyst bed CD col!mn is 2 M$a& #f a catalyst

can be fo!nd that is selective for formation of #$A, and not D#$E, the operating press!re can

be increased to ? M$a "Table 2%

&

)ocation of !eaction one

The location of the reaction 3one in the CD col!mn is determined by the relative


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*eed )ocation

The inlet to the col!mn for each feed has been located so as to ma/imi3e reactant

concentration in the reaction 3one, itho!t hindering the separation process occ!rring in the

other parts of the col!mn& #n the optim!m d!al catalyst bed CD col!mn config!ration, li(!id

ater is fed closely above the top of each of the catalyst beds, and propylene is fed

immediately belo the loer catalyst bed "ig!re %&

Alternative designs in hich feed streams are located higher in the stripping section or

loer in the rectifying section give !nsatisfactory performance& eeding reactants to the

stripping or the rectifying section leads to a red!ction in #$A concentration and an increase in

ater concentration in the li(!id prod!ct& This effect is a conse(!ence of a loer conversion

of ater to #$A in the reaction 3one, and red!ced efficiency in separation in the stripping

section&

4imilarly, for the single catalyst bed CD col!mn, ater is fed closely above the catalyst

bed, and propylene immediately belo the catalyst bed "ig!re 2%&


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than ater and #$A, and more than @t of each a3eotropes is D#$E& Therefore D#$E

concentrates in the middle of the CD col!mn "ig!re ?%& Fi(!id mi/t!re in the stripping

section of the CD col!mn comprises mainly ater and #$A& As #$A forms a3eotropes ith

ater, it ill only concentrate at the bottom of stripping section hen the #$A concentration

in the total reaction mi/t!re is higher than the concentration of #$A in the a3eotrope "9&6

mole fraction #$A%& >hen propylene and ater are fed to an e(!ilibri!m reactor of ?-9 at

-5- mole ratio, and chemical e(!ilibri!m is attained, the #$A molar ratio in the #$A and ater

mi/t!re of li(!id o!tlet is only 9&-8, loer than that in the ater and #$A a3eotrope

"sim!lation res!lt !sing e(!ilibri!m reactor model%& Therefore it is necessary that the ater

content of the li(!id mi/t!re is cons!med beyond the e(!ilibri!m limit attainable !sing a

stoichiometric feed to prod!ce high p!rity #$A& This is achieved by feeding an e/cess of

propylene into the reaction 3one& >hen the propylene;ater molar feed ratio is 2&+5-,

conversion of propylene to #$A in the d!al catalyst bed CD col!mn is 8, and the

concentration of #$A in the bottom stream is as high as ++&+mol& #n contrast, the e(!ilibri!m

conversion to #$A of the same feed mi/t!re is only @&?mol at the same temperat!re and


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hich in t!rn is a f!nction of the operating press!re& Conse(!ently, the amo!nt of propylene

converted to prod!ct and the amo!nt of propylene recycled vary ith temperat!re& At 2M$a

and propylene;ater molar feed ratio is 2&+5-, the reaction temperat!re is ?98 in the !pper

catalyst bed and ?-9 in the loer catalyst bed, nearly -99 of propylene cons!med in

reaction is converted to #$A& The optim!m val!es "2&+5-% for the feed ratio and the

temperat!re of reaction at 2M$a provide for optim!m col!mn performance hich 0eeping the

costs for recycling propylene at a reasonably lo val!e&

Distillate *lo. !ate

The distillate from the CD col!mn consists mainly of !nreacted propylene inerts carried

by the propylene feed stream& $ropylene is separated from the ma1ority of the propane and

other imp!rities in a separation !nit, and the propylene is recycled to the CD col!mn&

Contin!o!sly feeding and recycling propylene serves to increase the propylene concentration

in the reaction 3one, and thereby to drive the reaction beyond the e(!ilibri!m limitation&


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#$A concentration in the li(!id prod!ct stream on the ratio of distillate flo rate to propylene

feed rate is sho in ig!re 8& The concentration c!rve of #$A is volcano shaped& The #$A

concentration in the li(!id prod!ct reaches highest "++&+ mol% hen distillate;propylene

feed molar ratio is 9&68@ "Table %& At the optim!m temperat!re and press!re, D#$E forms

lo boiling point a3eotropes ith ater and #$A, and remains in the !pper part of stripping

section and the reaction 3one hile high p!rity #$A gathers at the bottom of the col!mn

"ig!re ?%& The compositions of different a3eotropes are listed in Table - ".erge et al& 28%& The

high concentration of D#$E in the reaction 3one inhibits formation of additional D#$E, and

propylene is hydrated to #$A& The li(!id mi/t!re floing don from reaction 3one into the

stripping section of the CD col!mn consists mainly of #$A as essentially all ater is

cons!med in the hydration reaction& #$A and ater form lo boiling point a3eotrope& The #$A

concentration in the li(!id stream on the top of the stripping section is higher than the #$A

content of a3eotropic mi/t!re& Therefore, #$A is collected at the bottom of the stripping

section and the a3eotrope rises to the top of the stripping 3one& Unli0e conventional propylene

hydration processes here e/tra col!mns are re(!ired to separate D#$E and ater from #$A,


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hen the distillate;propylene feed molar ratio 9&6-, the #$A mole fraction in the li(!id

prod!ct is only 9&@@ tho!gh total conversion of propylene is ?9&? mol& Up to @&8 mol of

propylene forms by)prod!ct D#$E, and only -&+mol propylene is converted to #$A& As

distillate;propylene feed molar ratio increases, D#$E concentration in the li(!id prod!ct

stream decreases hile #$A concentration increases "ig!re 8%& >hen the distillate;propylene

feed molar ratio goes higher than the optim!m val!e, less propylene is cons!med in the

reaction 3one& Therefore less #$A is formed and more !nreacted ater flos into stripping

section& >ater concentration in the li(!id prod!ct goes !p& Th!s, it is necessary to caref!lly

control the distillate flo rate to optimi3e the conversion of ater and p!rity of #$A prod!ced&

"ingle and 'ultiple Catalyst #ed CD Column

The CD col!mn ith a single catalyst bed located on the 8 thplate as first modeled, the

potential benefits of having to or more catalyst beds has also been determined& A higher

conversion of propylene is attainable, depending on the location and the n!mber of catalyst

bed& %& *igher conversion of #$A is achieved hen the second reaction is located on the rd


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A CD col!mn ith three catalyst beds each mo!nted on rd, 8th, and +th plates as also

st!died& es!lt shos the temperat!res of the !pper to catalyst beds decrease too& Foer

temperat!re in the catalyst bed leads to lo reaction rate and larger amo!nt of catalyst to be

!sed, therefore avoided in the present design& The #$A concentration in the prod!ct stream of

the single catalyst bed model increases to ++&+ hen the propylene;ater feed ratio is

increased to &@5-, b!t the conversion of propylene decrease to ?mol& The CD col!mn of

d!al catalyst beds mo!nted on the rdand 8thplates is the optim!m config!ration ith highest

propylene conversion and s!itable catalyst bed temperat!re&

Theoretical "eparation Plates

*aving determined the re(!irements for location of the reaction 3one and the optim!m

feed ratio, the n!mber of theoretical plates re(!ired for each of the rectifying and stripping

sections can be determined& The d!al bed CD col!mn model has been r!n to determine the

optim!m n!mber of plates in each section independently& The level of separation of the


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(ffect of %ther %perating and Design +ariables

The reactor can be operated so that the reaction 3one is at the temperat!re at hich the

catalyst is active& #on)e/changed resin, t!ngsten o/ide and 3eolite have been reported to have

high activity for the li(!id phase hydration of propylene to #$A "Eg!chi, et al& -6, aiser, et

al&2, $etr!s, et al&2?,%& >hen the reaction is in the range of 2 to ?8, an acid ion)

e/change resin catalyst "e&g& Amberlyst resin% can be !sed as the catalyst& The disadvantage

for the application of ion)e/change resins as heterogeneo!s catalysts is the increasing thermal

instability at elevated temperat!re "$etr!s, et al&28%& Therefore, for high temperat!re hydration

reactions it is necessary to !se acidic inorganic catalysts having high thermal stability&

The feed temperat!re has only a slight effect on the operation of the process& *oever,

the reaction is highly e/othermic, and so feeds that are slightly cooler than the catalyst beds

temperat!re have a beneficial effect in controlling reaction 3one temperat!re&

#n an alternative model, a combination of a pre)reactor and a CD col!mn can be !sed& #f

the rate of reaction is slo, a large amo!nt of catalyst is re(!ired& #n s!ch a case, !se of a pre)


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the state)of)the)art conventional processes and the ne CD process& E(!ipment for

conventional propylene hydration processes !s!ally consists of reactors ith cooling system

and a series of separation col!mns& >ater is a large component of the li(!id prod!ct stream&

Conse(!ently, e/cess ater has to be removed first thro!gh distillation to obtain the a3eotrope

mi/t!re& Then, e/tractive distillation is applied to brea0 the a3eotrope& inally, the e/tractive

agent remaining in the #$A has to be removed to meet the #$A prod!ct standards& Typically,

fo!r distillation col!mns are re(!ired to treat the prod!ct stream from a conventional reactor

to get high p!rity #$A "=eier and >oellner%& The proposed CD process consists of one

col!mn having a catalyst bed in the middle section& *igh p!rity #$A "++&+mol% is obtained

directly from the col!mn&

Clearly, the CD process is m!ch simpler to constr!ct and operate "Table ?%& !rther, it is

operated at a m!ch loer press!re and temperat!re than conventional li(!id phase hydration

processes& *ence, the capital and operating cost are red!ced dramatically, and operation is

more straightforard& The CD process also offers red!ction in operating costs arising from

reactor cooling, catalyst recycle, and ater recycle& A cost associate ith the ne process


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C%$C)&"I%$"

A process for the prod!ction of #$A ith a catalytic distillation col!mn has been

modeled& The !se of a CD process alleviates e(!ilibri!m limitation& The model shos that

high p!rity #$A "++&+mol% can be prod!ced as a li(!id prod!ct stream containing virt!ally

no ater, in contrast to conventional processes& The red!ction of ater content belo the

a3eotrope ater content occ!rs by reaction ith a 2&+5- optim!m molar e/cess of propylene&

E/cess propylene is recycled& The e(!ilibri!m ether content of the reaction mi/t!re is retained

in the reaction 3one& The optim!m operating press!re is 2)? M$a, and the col!mn temperat!re

range is 8)82, to allo sim!ltaneo!s reaction and separation of the reaction mi/t!re&


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!(*(!($C("

-& *ancoc0, E&G&, -+,Propylene and Its Industrial Derivatives&

2& roschit3, :& #&, -++-, ir0)'thmer Encyclopedia of Chemical Technology, 295 2-6)2?9&

& =eier, >&, >oellner :&, -+, #sopropyl alcohol by Direct *ydration, CHE!ECH, "eb%5

+8)++&

?& 'no!e, H&, Mi3!tani, H&, A0iyama, 4&, #3!mi, H&, -+@, *ydration ith >ater,

CHE!ECH, @5 ?2)??9&

8& 4avini, C&, -+@,Process for Improvin" Odor of Isopropanol# $ower %lcohols and Other

O&y Derivatives of $ower %lcohols, U $atent =o ,@,@6&

6& DeGarmo, :& F&, $ar!le0ar, B& =&, $in1ala, B&, -++2, Consider eactive Distillation,

Chemical En"ineerin" Pro"ress, March5 ?)89&

& oc0, &, Gildert, G&, McG!ir0, T&, -++, Catalytic Distillation, Chemical En"ineerin",

:!ly5 @)@?&

@& 4hoema0er, :& D&, :ones, E& M&, -+@, C!mene by Catalytic Distillation# Hydrocar'on


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-2& 4onnemanes, M& *& >&, -++, *ydration of $ropene over Acid Ieolites, %pplied

Catalysis %: +eneral# +?5 2-8)22+&

-& 'dioso, & C&, *en0e, A& M&, 4ta!ffer, *& C&, rech, & :&, -+6-, Direct *ydration of

'lefins ith Cation E/change esins,Industrial and En"ineerin" Chemistry, 8"%5 29+)

2--&

-?& =g, & T& T&, empel, G& F&, -+++, Catalytic Distillation, Canadian Chemical ,ews,

:!ly;A!g!st5 -+)29&

-8& $ilavachi, $& A&, -++, Modeling and 4im!lation of eactive Distillation 'perations, Ind)

En") Chem) *es&, 65 -@@)-+&

-6& Eg!chi, &, odiai, T&, Arai, *&, -+@, *igh $ress!re Catalytic *ydration of 'lefins over

$roton)E/changed Ieolites,%pplied Catalysis, ?5 28)2@&

-& $odrebarac, G& G&, =g, & T& T&, empel, G& F&, -++@, The $rod!ction of Diacetome

Alcohol ith Catalytic Distillation $art ##5 A ate).ased Catalytic Distillation Model for

the eaction Ione, Chemical En"ineerin" Science, 85 -9)-9@@&

-@& 4neeby, M& G&, Tade, M& '&, Datta, &, 4mith, T& =&, -++, ET.E 4ynthesis via eactive


23/35

22& ran0, .& D&, Dodge, .& &, -+8+, Bapor)Fi(!id E(!ilibri!m at *igh $ress!res, (ournal of

Chemical and En"ineerin" Data, ?"2%5 -9)-2-&

2& aiser, :& &, .e!ther, *&, Moore, F& D&, 'dioso, & C&, -+62, Direct *ydration of

$ropylene over #on)E/change esins,I/EC Product *esearch and Development, -"?%5

2+6)92&

2?& $etr!s, F&, De oo, & >&, 4tamh!is, E& :&, :oosten, G& E& *&, -+@?, inetics and

E(!ilibria of The *ydration of $ropene over a 4trong Acid #on E/change esin as

Catalyst, Chemical En"ineerin" Science, +"%5 ?)??6&

28& $etr!s, F&, 4tamh!is, E& :&, :oosten, G& E& *&, -+@-, Thermal Deactivation of 4trong)Acid

#on)E/change esins in >ater,Ind) En") Chem) Prod) *es) Dev&, 295 66)-&

26& 4!baalla, *, air, :& &, -+++, Design G!idelines for 4olid)Cataly3ed eactive

Distillation 4ystems,Ind) En") Chem) *es)#65 6+6)9+&


24/35

ADDE44

Correspondence concerning this paper sho!ld be addressed to $rofessor &T& Ch!ang,

Department of Chemical and Material Engineering, 86 Chemical and Material Engineering

.!ilding, University of Alberta, Edmonton, Canada, T6G 2G6& $hone5 @9)?+2)?66, a/5

@9)?+2)2@@- E)mail5 arlT&Ch!angJUalberta&ca&


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EACT' 4E$AAT' AIE' C'FUM=

$'$HFE=E

F#G*T E=D C'FUM=

>ATE


26/35

0i"ure 2)Config!ration of single catalyst bed catalytic distillation col!mn&

$ropylene feed

>ater feed

#$A d

$ropylene ecycle


27/35

$ropylene ecycle

$ropylene feed

>ater feed

>ater feed


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0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Stage

MoleFraction

WATER

PROPYLENE

IPA

PROPANE

DIPE


29/35

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.61 0.62 0.63 0.64 0.65 0.66 0.67 0.68 0.69 0.70

M

oleFraction

0.86

0.88

0.90

0.92

0.94

0.96

0.98

1.00

1.02

MoleFraction

#$A

ater

D#$E


30/35

9&+@+8

9&++99

9&++98

9&++-9

9&++-8

-9 -8 29 28 69 68

$umber of Plates in "tripping "ection

IPA'ole*ra

ctionin)i/uidProduc

t


31/35

0i"ure 6) lo diagram of catalytic distillation isopropyl alcohol process&

a& The dashed line part of the diagram is incl!ded in the to reaction)3one catalytic distillation process

$ropylene

'lefin

efinery

4 -

4 2

>ater

$-

$2

$

*-

*2

$?

$8

*igh $!rity #$A

CD

4

*igh $!rity #$A


32/35

!a'le1) A3eotropes of >ater)#$A)D#$E 4ystem&

compo!nd boiling temperat!re composition of a3eotrope

or a3eotrope of a3eotrope ater #$A D#$E

"% t t t

ater &-

#$A 88&68

D#$E ?2&-8

aterK#$A 8&?8 -2&6 @&

#$AKD#$E +&8 9 -6& @&

aterKD#$E 8&8 ?&8 9 +8&8

aterK#$AKD#$E ?&8 ?& & @@&9

#$A5 isopropanol D#$E5 diisopropyl ether

2


33/35

!a'le 2) Effect of Distillate;$ropylene atio on CD Col!mn $erformance

distillate;propylene feed molar ratio 0.6170 0.6580 0.6890

#$A mole fraction in prod!ct stream 9&@@9 9&+++- 9&+9@6

total propylene conversion mol 40.4036 36.1801 32.8649

ater conversion mol 0.9976 0.9975 0.9060

propylene conversion to #$A mol 31.9373 36.1529 32.8528

propylene converison to D#$E mol 8.4663 0.0272 0.0121

Later;propylene molar feed ratio7-52&+


34/35

!a'le 3) Comparison of M!ltiple and 4ingle Catalyst .ed CD Col!mn&

catalyst b! catalyst b! t"#$at%$ &'( IPA )* l)+%)! #$,!%ct #$,#yl*-at$ #$,#yl* c,*/$s),*

3$! #lat 5t #lat 9 t #lat ",l $act),* ! ",la$ $at), ",l

1 409 0.994 2.91 34

1 410 0.999 3.81 26

2 324 409 0.993 2.91 34

3 322 324 409 0.993 2.91 34

2 405 410 0.999 2.91 35

?


35/35

!a'le 7& Comparison of $ropylene *ydration $rocesses&

direct hydration fi/ed)bed tric0le)bed

process vapor phase mi/ed phase li(!id phase catalytic distillation

$' feed stream "t%L ++ +2 +8 +8

catalyst >')In';*$'? ion)e/change resin a(!eo!s silicot!ngstate LL

catalyst regeneration no no yes no

reactor yes yes yes no

cooling of reactor yes yes yes no

distillation col!mn in process ? ? ? -

operating press!re "M$a% 2&8)6&6 @)-9 29& 2

operating temperat!re "% 8-)82 ?9)? 8-)86 ?)82

feed ratio "ater;$'% -5?)-9 -2)-85- -52&+

$' recycle;feed mole ratio +?)+8 28 9)?9 68

ater recycle;feed mole ratio ?9)@9 +?)+8 9

conversion 8)6 $' 8 $' 69)9 $' 8 $', ++ ater

#$A selectivity +6 + +@)++ +8

L $'7propylene LL 3eolite or proton)e/changed resin

8

introduction 6

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