Acetic Acid Separation Methods

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 DistillationPhysical 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:NonvolatileHigh boiling point Make large difference in volatility between componentsMiscible with mixture and doesn´t form azeotropic

mixtureCommercially available and inexpensiveNoncorrosivePhysically 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