Post on 16-Dec-2015
Acetic Acid Separation Methods
Supervisore: Prof. H. S. Ghaziaskar By: H. Rastegari
Contents
Acetic Acid Uses
Acetic Acid Production
Acetic Acid Separation methods
Conclusion
References
1
In vinyl acetate monomer productionIn acetic anhydride production As solvent in production of terphetalic acid As recrystalization solventIn SilageIn production of various acetates such as:
Sodium acetate Copper acetate Aluminum acetate Palladium acetate
Acetic Acid Uses
2
Acetic Acid Production
Chemical processes for acetic acid production:
Reaction of methanol with carbon monoxide Reaction of acetylene with water followed by air oxidation Fermentation of ethanol Butane oxidation
3
Other chemical processes which produce acetic acid as a by-product:
Manufacture of cellulose esters
Reactions involving acetic anhydride
Synthesis of glyoxal from acetaldehyde and nitric acid
Wood distillate
4
Problem
Separating acetic acid from water
5
6
Separation Methods
Separation Involving Phase Changes:
Simple Distillation Azeotropic Distillation Extractive Distillation Reactive Distillation
Separation involving membranes:
Pervaporation Evapomeation Temperature Difference Evapomeation Electrodialysis Bipolar Membrane Electrodialysis
Simple Distillation
Physical separation process based on differences in volatilities
7
Advantage
Simple and easy to operate
8
Disadvantage Large energy consumption
Azeotropic Distillation
Distillation in the presence of entrainer
9
Desirable properties for an azeotropic entrainer :
Heterogeneous azeotrope
Commercially available and inexpensive
Nontoxic
Chemically Stable
Noncorrosive
Low heat of vaporization
The best entrainer is:
Alkyl Acetate
10
Effective parameters for alkyl acetate selection
Azeotropic temperature
Azeotropic composition
Aqueous phase composition and entrainer pricing
11
Advantage
Improving the economics of the separation
Disadvantage
Requiring large amount of entrainer
12
Extractive Distillation
Distillation in the presence of solvent
13
Desirable properties for solvent:
Nonvolatile
High boiling point
Make large difference in volatility between components
Miscible with mixture and doesn´t form azeotropic mixture
Commercially available and inexpensive
Noncorrosive
Physically and chemically stable
14
The best solvent is:
Trialkyl Amine
Advantage
Relatively little energy consumption
Disadvantage
Need additional heat requirement on the column
Some what larger plates
15
Reactive Distillation
Chemical separation method which combines simultaneous chemical reaction and multicomponent distillation in the same vessel
16
Mechanism of reaction:
First Step:
Second Step:
Third Step:
17
Effect of various parameters on the acid conversion
Total feed flow rate
Optimum value:192 mL/h
Mole ratio
18
Reflux configuration Feed position
19
Pervaporation (PV)
separation of liquid mixtures by partial vaporization through membrane
20
Used membrane
Polydimethylsiloxane (PDMS)
Cross-linked polybutadiene
Silicalite-1 as adsorbent filler in PDMS membrane
Carbon molecular sieve in PDMS membrane
Silicalite-1(pure silica)
Ge-ZSM-5
Sn-ZSM-5
20
Effective parameters on separation performance
Si/Sn
Temperature
Acid concentration
Disadvantage
Shrinking and swelling of the membrane
21
Evapomeation(EV)
Vaporization of feed solution then permeation through polymeric membrane
22
Effective parameters on separation performance
Temperature
Acid concentration
Disadvantage
membrane condensation in high acid concentration
23
Temperature Difference Evapomeation (TDEV)
Decreasing temperature in the membrane surrounding than in the feed solution
24
Electrodialysis (ED)
Ion transportation from one solution through ion- exchange
membranes to another solution under the influence of an
electric potential difference
25
Application
Concentrating acetic acid from water containing %1(w/w)
acid to %10(w/w)
26
Importance
Make full use of our limited resources
Protect our environment
Disadvantage Concentration efficiency up to %10
Low electric current efficiency (around %20)
27
Bipolar Membrane Electrodialysis (BME)
28
Application
Concentrating acetic acid from water containing %0.2(w/w)
acid to %14(w/w)
Disadvantage
Low electric current efficiency (around %40)
29
Conclusion
For high purity (%99.9) acetic acid Azeotropic Distillation
For reasonably pure acetic acid Extractive Distillation
For ester production Reactive Distillation
For separation from solution containing % (5-15) acid PV
30
References
[1] Garwin, L., Hutchisoni, K., E., 1950. Industrial And Engineering
Chemistry 42(4), 727-730.
[2] Othmer, D., F., 1935. Industrial And Engineering Chemistry 27(3),
250-255.
[3] Lee, F., M., Wytcherley, R., W., Distillation, Academic Press, USA,
2000.
[4] Chien, I., L., Kuo, C., L., 2006. Chemical Engineering Science 61,
569-585.
[5] Wang, S., J., Lee, C., J., Jang, S., S., Shieh, S., S., 2008. Process
Control 18, 45-60.
[6] Garwin, L., Haddad, P., O., 1953. Industrial And Engineering Chemistry
45(7), 1558-1562.
[7] Lei, Z., Li, C., Li, Y., Chen, B., 2004. Separation And Purification
Technology 36, 131-138.
[8] Taylor, R., Krishna, R., 2000. Chemical Engineering Science 55, 5183-
5229.
[9] Saha, B., Chopade, S., P., Mahajani, S., M., 2000. Catalysis Today 60,
147-157.
[10] Yu, L., Guo, Q., Hao, J., Jiang, W., 2000. Desalination 129, 283-288.
[11] Sun, W., Wang, X., Yang, J., Lu, J., Han, H., Zhang, Y., Wang, J.,
2009. Membrane Science 335, 83-88.
[12] Li, G., Kikuchi, E., Matsukata, M., 2003. Separation Purification
Technology 32, 199-206.
[13] Toti, U., S., Kariduraganavar, M., Y., Soppimath, K., S., Aminabhavi,
T., M., 2002. Applied Polymer Science 83, 259-272.
[14] Asman, G., Anl, O., 2006. Separation Science And Technology 41(6)
1193-1209.[15] Asman, G., Sanli, O., 2006. Applied Polymer Science 100, 1385-1394.
[16] Chien, I., L., Zeng, K., L., Chao, H., Y., Liu, J., H., 2004.Chemical Engineering Science 59, 4547-4567.
[17] Kittur, A., A., Tambe, S., M., Kulkarni, S., S., Kariduraganavar, M.,
Y., 2004. Applied Polymer Science 94, 2101-2109.
Thanks for your attention
Glyoxal:
Acetic Acid Production
VHAC= (yHAC) / (xHAC)
VH2O= (yH2O) / (xH2O)
Dalton's Law:
PH2O= (yH2O) * pt
Raoult's law: PH2O= (xH2O) * p0
H2O
Simple Distillation
α = VH2O / VHAC
Fenske Equation:
(yH2O)/(1- yH2O) = αn+1 (xH2O)/(1- xH2O)
Azeotropic Distillation
Extractive Distillation
Solvent volume