1
1..00 IINNTTRROODDUUCCTTIIOONN
Acrylic acid’s chemical nature makes it a highly desirable component in a polymer Acrylic acid’s chemical nature makes it a highly desirable component in a polymer system. Beside
system. Besides polymer applications, the molecule also follows the s polymer applications, the molecule also follows the charactercharacteristics of both istics of both aa carboxyli
carboxylic acid c acid and acrylate ester, makinand acrylate ester, making it g it suitable for chemical intermedisuitable for chemical intermediates as ates as well. Thewell. The largest application for acrylic acid is in the industrial coatings area. And, because it is largest application for acrylic acid is in the industrial coatings area. And, because it is miscible with water, alcohols, and ethers, the wetting ability can be enhanced based on the miscible with water, alcohols, and ethers, the wetting ability can be enhanced based on the specific employm
specific employment. An area of ent. An area of growth for acrylic acid is growth for acrylic acid is with acrylic acid homo-polymerswith acrylic acid homo-polymers and acrylic acid/starch grafts. These combinations proide a high rate of absorption, perfect and acrylic acid/starch grafts. These combinations proide a high rate of absorption, perfect for use in hygiene products. !ther minor uses include iscosity modifiers for rubber lattices for use in hygiene products. !ther minor uses include iscosity modifiers for rubber lattices and adhesies, detergents, fiber si"ing, and soil conditioner.
and adhesies, detergents, fiber si"ing, and soil conditioner. Acrylic acid is formed by the following reaction#
Acrylic acid is formed by the following reaction# $
$%%&&'' ( ).* ! ( ).* !++ →→ $$%%&&!!++ ( & ( &++!!
$omplicating matters are two competing side reactions# $omplicating matters are two competing side reactions#
$
$%%&&'' ( +.* ! ( +.* !++ →→ $ $++&&!!++ ( $! ( $!++ ( & ( &++!!
$ $%%&&'' ( .* ! ( .* !++ → → % $! % $!++ ( % & ( % &++!!
The first competing reaction forms acetic acid, which is a marketable commodity. The second The first competing reaction forms acetic acid, which is a marketable commodity. The second competing reaction simply forms completely useless products.
competing reaction simply forms completely useless products. The specifications to meet for the production of acrylic acid were# The specifications to meet for the production of acrylic acid were#
•
• eedstock# ropyleneeedstock# ropylene •
• roduct spec# . wt0 minimumroduct spec# . wt0 minimum •
• &as to consider competing side reactions inside the reactor &as to consider competing side reactions inside the reactor •
• roduct capacity# *1,111 2TAroduct capacity# *1,111 2TA
2
2..00 CCHHEEMMIICCAAL PL PRROOCCEESSS SS SEELLEECCTTIIOONN
3election )# 2anufacture of Acrylic Acid by 3ingle-step $atalytic ropylene !xidation. 3election )# 2anufacture of Acrylic Acid by 3ingle-step $atalytic ropylene !xidation. 43elected for 35 in the case study6
43elected for 35 in the case study6
The first process inoles direct catalytic oxidation of propylene to acrylic acid in a single The first process inoles direct catalytic oxidation of propylene to acrylic acid in a single stage operation which comprises passing a starting reactant gas mixture containing propylene, stage operation which comprises passing a starting reactant gas mixture containing propylene, com
comprespressed air sed air 4com4comprespressor6 and sor6 and steasteam m 4mi4mixer6 througxer6 through h in in a a singsingle le reacreactor 4lug tor 4lug flowflow reactor6. The reactor effluent is sent to a separation unit 4separator6 in which all light gases reactor6. The reactor effluent is sent to a separation unit 4separator6 in which all light gases are separated as apor in top stream. Bottom stream that contains mixture of li7uid mainly are separated as apor in top stream. Bottom stream that contains mixture of li7uid mainly water, acetic acid and acrylic acid are distilled to produce purified acrylic acid 4distillation water, acetic acid and acrylic acid are distilled to produce purified acrylic acid 4distillation column6.
column6.
3election +# 2anufacture of Acrylic Acid by Two-step $atalytic ropylene !xidation. 3election +# 2anufacture of Acrylic Acid by Two-step $atalytic ropylene !xidation.
Another process inoles producing acrylic acid from propylene through acrolein as an Another process inoles producing acrylic acid from propylene through acrolein as an intermediate by catalytic apor phase oxidation, which comprises passing a starting reactant intermediate by catalytic apor phase oxidation, which comprises passing a starting reactant gas mixture containing propylene, compresse
gas mixture containing propylene, compressed air d air 4compres4compressor6 and sor6 and steam 4mixer6 through asteam 4mixer6 through a first-stage reactor packed with a molybdenum-containing multi-component catalyst 4plug first-stage reactor packed with a molybdenum-containing multi-component catalyst 4plug
flow reactor6, passing the resulting acrolein containing gas through a second-stage reactor packed with a multi-component catalyst containing anadium and molybdenum 4plug flow
reactor6. The resulting acrylic acid-containing gas is separated 4separator6, and absorbed in water 4absorber6. A part of the exhaust gas is incorporated in the starting reactant gas mixture 4recycle6.
3.0 DESIGN METHOD
3oftware 8sed# 8ni3im 3oftware 42odular Based 2ethod6
Unit Operation Fn!tion
$ompressor 49-)116 To compress air from atmospheric pressure and increase the temperature.
2ixer 42:;-)116 To mix propylene, compressed air and steam.
&eater 4<-)116 To heat incoming mixture to re7uired temperature for reaction to be occurred. lug flow reactor 4=-)116 !xidation of propylene to final desired
product acrylic acid, acetic acid as by- product.
3eparator 4>-)116 To separate gases and li7uid components in reactor effluent.
5istillation column 4T-)116 To produce purified distillation column after gases and li7uid components are separated. ".0 SIMULATION OF PSD
lease refer to A<?5:; A.
#.0 RESULTS
lease refer to A<?5:; A.
$.0 ANAL%SIS
:mproement to the 35#
• @ower temperature of incoming feed of reactant gases from +**.' ℃ to +*1 ℃
4min temperature re7uired for the function of catalyst6 increase mass flow of acrylic acid since it is an exothermic reaction. (Refer APPENDIX B for results after improvement)
hen perform economic analysis, a number of economic criteria should be used. :t is the e7uialent annual operating cost 4<A!$6. A negatie <A!$ means there is a profit. :t is desirable to minimi"e the <A!$ i.e., a large negatie <A!$ is ery desirable.
2aterial $ost C Total eed $ost ( Total <nergy $ost C D 4,E1,11 ( +1*,FE),11*6
C & 2##'3"1'"0#
8nit !peration $ost C Total urchase $ost ( :nstallation $ost C D 4%1,+%' ( *,+*,+)6
C& $'1(#'"##
<A!$ C - D 4product alue - feed cost - other operating costs - capital cost annuity6 C - D 4)%),F,E+1 G ,E1,11 G +1*,FE),11*G ),+%1,E+6
) & 12"'#(3'1#(
ayback period C D4,E1,11 ( +1*,FE),11*( ),+%1,E+6/ D )%),F,E+1 ) 1.*" +ear,
&oweer, since this only considers the main unit operations of the process, true profit cannot be calculated at this time. Also, there are assumed errors in such a cost study as the labor cost,
maintenance cost, other pumps or ales that are not considered.
Note: Economic or environmental analysis are shown in APPENDIX !
(.0 DISCUSSION
This process produces *%,'1 metric tons per year of . mole 0 of acrylic acid 4AA6 product. The number of operating hours should be taken as F111/yr, about %%1 days which allows the plant for periodic shut down and maintenance. The reactor in the process shown uses a proprietary catalyst that eliminates the production of the intermediate, acrolein. Therefore, this process re7uires only a single reactor.
After reaction, it is essential to cool the products 4reactor effluent6 7uickly to aoid further homogeneous oxidation reactions. The homogeneous combustion reactions will not take place so long as the reactor effluent is cooled to below )11o$ immediately after the
reactor. Additional recoery of AA and acetic acid 4a by-product6 from the gas leaing the phase separator is achieed in the distillation column.
The kinetics used for the % reactions inoled are alid in the temperature range, +*1 G %%1o$ 4=efer to Appendix $6. Aboe %%1o$ the catalyst starts to coke, and below +*1o$ the
rate of reaction drops off rapidly. :t is recommended that the steam-to-propylene ratio at the reactor inlet neer be set less than #) on a mole basis. This steam is used to inhibit the formation of coke on the catalyst below temperatures of %%1o$.
As a conclusion, oxidation of propylene produces acrylic acid as main product with .0 purity after purification in distillation column. Two other competing reactions which produced acetic acid as useful by-product and carbon dioxide as non-added alue by product
are also considered in the designing of the process. Acrylic acid is produced at a rate of ''F+.*kg/h, which is e7ual to *%,'1 metric tons per annum.
*.0 APPENDI
*.1 APPENDI A/ PSD AND RESULTS A.)# 3imulation of 35#
4a6 3imulation with producing acrylic acid#
4b6 3imulation with further purification of acetic acid 4predicted using shortcut distillation6#
A.+# =aw material 4$ompressed air, propylene and steam6# $ompressed air#
ropylene#
3team#
A.# By-product 4>ent gas and acetic acid6 >ent gas#
Acetic acid for further purification#
Acetic acid 4predicted using short cut distillation6#
Analysis results for lowering the temperature of incoming feed#
Teperatre 2##.$ ℃ 2#0 ℃
5uty of heater 4kH/h6 ,'*F,E)1 *E,FF+ &eater electricity 4D6 '+),)+1 E%,1*1
Acrylic acid 4kg/h6 ''F+.* 'E+.+
rofit of acrylic acid per annum 4D6
)%),F,E+1 )%+,F+%,11
Analysis results for reducing si"e of reactor#
Analysis results for reducing pressure of compressed air#
Pre,,re # at ".#at " at
5uty of compressor 4k6 +''+.1% +%E.'' +)'.%* $ompressor electricity 4D6 ),+EE,E'1 ),)E1,1E' ),1*,+F Temperature of reactants inlet stream 4 ℃¿ +**.' +.E +%%.1
Acrylic acid 4kg/h6 ''F+.* ''E+.F ''*'. rofit of acrylic
acid per annum 4D6
*.3 APPENDI C/ ECONOMIC OR ENIRONMENTAL ANAL%SIS
Raw material: ropylene D1. / lb
Pro"uct: Acetic acid D1.'F / lb
Acrylic acid D).)+ / lb
#tility: @ow pressure steam 4'11ka saturated6 D'.'+/)111kg
<lectricity D1.1'/k h
$ooling water 4*)'ka and %1 ° C 6 return pressure I%1Fka
D1.)'/JH return temperature is no higher than * ° C =efrigerated water 4*)'ka and )1 ° C 6
return pressure I%1Fka D).'1/JH
return temperature is no higher than +1 ° C
=efrigeration D'1/JH
E$uipment: Khttp#//www.matche.com/e7uipcost/=eactor.htmlI $ompressor 4Air, $entrifugal, )+*psi6
&eater
3eparator 4*E.'cm diameter6
lug flow reactor - D+1 to D*1 per s7uare foot of surface area 45C%.'m, @C)1m AC)%%.*m+K%E.FftI6
5istillation column 4ft diameter, )ft high6 E$uipment cost factors:
ressure 4absolute6 K )1atm, 1.1 )1-+1atm, 1.' +1-1atm, %.1 1-*1atm, *.1 *1-)11atm, )1 $arbon steel 1.1 3tainless steel .1
Co,t Crrent Pro!e,, &4 ropylene eed ,E1,11 =eboiler <lectricity 1,)+,111 $ondenser <lectricity 1,),111 Air $ompressor <lectricity
),+EE ,E'1 &eater <lectricity
'+),)+1 =eactor <lectricity
++,%',F11 3team from Boiler
*),%+* Total
255,341,405
E5ipent Pr!6a,e Co,t &4 In,ta77e8 !o,t &4 =eactor 4=-)116 +),F1 %1','1 Air $ompressor 49-)116 '1,11 +,E'),'11 &eater 4<-)116 ),'+ *F+,F1' 2ixer 42:;-)116 ),*11 +),111 3eparator 4>-)116 )*,11 )%,)11 5istillation $olumn 4T-)116 )*F,)E ),%1,+*% %otal &'*'+ ,*-,*.&
Total Capital Cost
<A!$ C - 4product alue - feed cost - other operating costs - capital cost annuity6
$apital cost annuity C $:
i
(
i+
1)
n(
i+
1)
n−
1where $: is the installed cost of all e7uipment i is the interest rate, i C 1.)* and n is the plant life for accounting purposes, n C )1.
10.0 REFERENCES
Acrylic Acid rices and ricing :nformation. 4+1)), August6. =etrieed %rd April +1)' from
http#//www.icis.com/resources/news/+11E/))/1)/1EF'/acrylic-acid-prices-and -pricing-information/
Acrylic Acid roduction and 2anufacturing rocess. 4+11E, ?oember 1)6. =etrieed +nd
April +1)' from http#//www.icis.com/resources/news/+11E/))/1)/1EFE+/acrylic-acid-production-and-manufacturing-process/
Acrylic Acid 8ses and 2arket 5ata. 4+11E, ?oember 1)6. =etrieed %rd April +1)' from
http#//www.icis.com/resources/news/+11E/))/1)/1EFE1/acrylic-acid-uses-and-market-data/
Anonymous. 4+1)6. 5esign of Acrylic Acid roduction. =etrieed %rd April +1)' from
http#//www.chemeng.kmutt.ac.th/cheps/roLect-MAcrylic-Acid.pdf
$ampbell, . <., 2c5aniel, <. @., =eece, . &., illiams, H. <., Noung, &.3. 4)E16. !xidation of ropylene to Acrylic Acid oer a $atalyst $ontaining !xides of Arsenic, ?iobium, and 2olybdenum. =etrieed )st April +1)' from
http#//pubs.acs.org/doi/abs/)1.)1+)/i%'11%*a1)+OLournal$odeCiepra'.)
&an, 3. 4+1)%6. 2ethod for preparing acrylic acid from propane and propylene. =etrieed +nd
April +1)' from http#//www.google.com/patents/!+1)%1*FFFFA)OclCen
@akowski, $., &ayenga, 2., $astillo, 2. 4)F6. Acrylic Acid roduction ia the $atalytic artial !xidation of ropylene. =etrieed %rd April +1)' from
http#//www.owlnet.rice.edu/Pceng1%/gr)F/AcrylicAcid.htm
rocess for producing acrylic acid from propylene. 4)E6. =etrieed +nd April from
http#//www.google.com/patents/83)EFF*
=eactor $ost <stimate. 4n.d.6. =etrieed %rd April +1)' from
http#//www.matche.com/e7uipcost/=eactor.html
3ood, 3. 4)*6. !ne 3tep !xidation of ropylene to Acrylic Acid. =etrieed %rd April +1)'
from http#//www.collectionscanada.gc.ca/obL/s/f+/dsk%/ftp1*/m7++1.pdf
Qhao, $., achs, :. <. 3electiity oxidation of propylene to acrolein oer supported >+!*/?b+!* catalysts. =etrieed )st April +1)' from
http#//lehigh.edu/operando/ublications/+11'0+1ropylene0+1to0+1acrolein0+1>- ?b+!*.pdf
