ADSORPTION AND STRIPPING OF ETHANOL FROM AQUEOUS

SOLUTION USING SEPABEADS207 ADSORBENT

M A ZIN ABDULHUSSEIN BEDEN

U N IV ERSITI TE K N O L G I M ALAYSIA

ADSORPTION AND STRIPPING OF ETHANOL FROM AQUEOUS

SOLUTION USING SEPABEADS207 ADSORBENT

M A ZIN ABDULHUSSEIN BEDEN

A dissertation subm itted in fulfillm ent of the

requirem ents fo r the aw ard o f the degree of

M aste r o f E ngineering (Chemical)

Faculty o f Chem ical E ngineering

U niversiti Teknoiogi M alaysia

JANUARY 2015

To my beloved family

ACKNOWLEDGEMENT

I would like express my sincere gratefulness to Allah for giving me strength

and wisdom in whole my studying. Also I want to take this opportunity to introduce

my gratefully acknowledge to my supervisors Dr. MUHAMMAD ABBAS AHMAD

ZAINI and Dr. TUAN AMRAN TUAN to help me in this work. Their dedication,

skillful guidance, helpful suggestions and encouragement made me able to deliver a

dissertation in an appreciable quality and standard, also I want to introduce my

thanks to Dr. UMI AISAH to help me in first part o f the thesis.

Deep appreciation I want to introduce to my family especially my dear wife to

give me the hope and concentrate on my study.

I owe my special thanks to my friend Safaa Abdulhussein and to lab. mates

Mr. Mohammad Latfi, Mr. Ahmad Bukhairy, Mr. Mohammed Rafiza, Mr. zulkifli,

Miss.Saadiah, Mr.Mohamad Halim and Miss. Aishah for their kindness, helping me

and sharing their experience. Great thanks to all staff o f chemical engineering

department to support and advise me to finalize my project.

ABSTRACT

There is a problem of increasing of CO2 and CO in environment from the

use o f fossil fuel. Ethanol is a good alternative fuel or additive to gasoline to

improve octane number, using ethanol will decrease CO and CO2 emissions. For

these reasons, production o f ethanol by fermentation is a promising solution. This

work aimed to evaluate suitable technique of separation using adsorption method.

Best conditions of adsorption and stripping processes were studied in this work. The

ethanol solution with 10wt% concentration, i.e., similar to the product of

fermentation process was used as feed. The separation was occurred in adsorber tube

containing polymer Sepabeads207 at different temperatures (20 - 40°C), also (pH) (4

- 7), time o f adsorption (5 - 25 minutes). Also time of stripping (desorption) was

studied between 15 and 35 minutes at different temperatures of air (80 - 95°C). The

evaporated ethanol was condensed by cold water and the concentration o f liquid

ethanol was measured using refractometer and gas chromatography. The results

show the best conditions for adsorption process are: time = 5 minutes; temperature =

20 °C and pH= 4, while the best conditions for striping process are: time = 15

minutes and temperature = 80 °C. By applying the best conditions for both

adsorption and stripping processes, ethanol concentration o f 46wt% was able to be

obtained. The adsorbent capacity o f Sepabeads207 is 0.22g ethanol/g adsorbent,

while the adsorbent selectivity is 7.75 — g e th a n o l/ g w ater ( adsorbed)— theg e th a n o l/g w ater (original so lu tio n )

efficiency o f adsorbent is 100%. From this study can be concluded that using of

Sepabeads207 to adsorb ethanol in static solution better than continues with applying

best conditions.

ABSTRAK

Terdapat masalah dengan peningkatan CO2 dan CO dalam persekitaran hasil

daripada penggunaan bahan api fosil. Etanol adalah pilihan bahan api yang baik atau

sebagai bahan tambah dalam petrol untuk meningkatkan nombor oktana, penggunaan

etanol akan mengurangkan pelepasan CO dan CO2. Justeru, penghasilan etanol

melalui penapaian merupakan bakal jalan penyelesaian. Kajian ini bertujuan untuk

menilai teknik pemisahan yang sesuai dengan kaedah penjerapan. Keadaan terbaik

proses penjerapan dan pelucutan telah dikaji. Larutan etanol berkepekatan 10wt%,

iaitu kepekatan yang sama dengan produk proses penapaian digunakan sebagai

suapan. Pemisahan berlaku dalam turus penjerapan yang mengandungi polimer

Sepabeads207 pada suhu (20 - 40°C), juga pH (4-7), dan masa penjerapan (5 - 25

minit) yang berbeza. Juga masa pelucutan (penyahjerapan) dikaji di antara 15 dan 35

minit, dan pada suhu udara yang berbeza (80 - 95°C). Etanol tersejat telah dicairkan

dengan air sejuk dan kepekatan cecair etanol diukur dengan refraktometer dan gas

kromatografi. Keputusan menunjukkan keadaan terbaik untuk proses penjerapan

ialah: masa = 5 minit; suhu = 20°C dan pH = 4, manakala keadaan terbaik untuk

proses pelucutan ialah: masa = 1 5 minit dan suhu = 80°C. Dengan menggunakan

keadaan terbaik untuk kedua-dua proses penjerapan dan pelucutan, kepekatan etanol

46wt% telah diperolehi. Muatan penjerap Sepabeads207 ialah 0.22g etanol / g

penjerap, manakala pemilihan penjerap ialah 7.75 dan kecekapan 100%. Daripada

kajian ini dapat disimpulkan bahawa Sepabeads207 menjerap etanol lebih baik dalam

larutan statik berbanding turus dengan mengenakan keadaan terbaik.

TABLE OF CONTENT

C H A PT ER T IT L E PA G E

D ECLA RA TIO N ii

D ED CA TIO N iii

A C K N O W LED G EM EN TS iv

ABSTRA CT v

A B STR A K vi

TABLE O F C O N TEN T vii

LIST O F TABLES x

LIST O F FIG U R ES xi

LIST O F SYM BOLS xiii

L IST O F A BBREVIATION S xv

LIST O F A PPEN D EC IES xvi

1 IN TR O D U C TIO N 1

1.1 Background of the Study 1

1.2 Problem Statement 2

1.3 Objectives 3

1.4 Scope 3

2 LITR A TU R E R EV IEW

2.1 Introduction 5

2.2 The Behavior of Azeotropic Ethanol / W ater 6

2.3 Various Types of Distillation Processes 11

2.4 Process of Extractive Distillation 12

2.4.1 Extractive Distillation by Salt 14

2.4.2 Extractive Distillation with Liquid Solvent 17

2.4.3 Extractive Distillation with the Combination ofLiquid Solvent and Solid Salt 18

2.4.4 Extractive Distillation with Ionic Liquid 19

2.5 Pervaporation Technique 20

2.6 Adsorption Technique 22

2.6.1 Zeolite 23

2.6.2 W ater Adsorption 27

2.6.3 Ethanol Adsorption 29

2.7 Concluding Remarks 30

3 M ETH O D O LO G Y

3.1 Introduction 32

3.2 Chemicals and apparatus 33

3.2.1 Chemicals 33

3.2.2 Apparatus 33

3.3 Preparation of ethanol Solution 36

3.4 Experimental Set-Up 37

3.5 Methodology 38

3.5.1 Adsorbing Study 38

3.5.2 Stripping Study 40

3.5.3 Adsorption Performance o f Sepabeads207 40

3.6 Determination o f Calibration Curve for Ethanol Concentration 41

4 RESULTS AND DISCUSSION

4.1 Introduction 43

4.2 Parameters Affecting Adsorption Process 44

4.2.1 Effect of Temperature on Adsorption Process 44

4.2.2 Effect of pH on Adsorption Process 46

4.2.3 Effect of Time on Adsorption Process 48

4.3 Stripping Process 50

4.3.1 Effect of Time on Stripping Process 51

4.3.2 Effect of Temperature on Stripping Process 53

4.4 Evaluation o f Best Conditions for Adsorption and Desorption Processes 55

4.4.1 Adsorbent Capacity 56

4.4.2 Adsorbent Selectivity 57

4.4.3 Efficiency o f Adsorbent 58

4.5 Comparison between the Results of Gas Chromatography andRefractometer 58

5 CO N CLU SIO N AND RECO M M EN D A TIO N

5.1 Conclusion 61

5.2 Recommendation for Future W ork 62

R E FER E N C E S 63

A PPEN D ICES 67

LISTS OF TABLES

TABLE NO. T IT L E PA G E

2.1 Properties o f Ethanol 6

2.2 Summary o f the binary systems with different salts 16

2.3 Examples o f the liquid solvents commonly used in the extractive Distillation 17

2.4 The influence of various solid salt and liquid solventson the relative volatility of ethanol and water 18

2.5 Comparison for techniques of separation ethanol fromwater ethanol mixture 31

3.1 Adsorbent Properties (Sepabeads207) 33

4.1 Adsorbed ethanol concentration by applying bestconditions 55

4.2 Error analysis o f the results o f G.C and refractometer 60

LIST OF FIGURES

FIG U R E NO. T IT L E PAGE

2.1 Ethanol (1) -Water (2) Composition Curve 8

2.2 VLE plot for ethanol (1)/ water (2) system showing liquid composition C2 produces and vapor composition C3 9

2.3 Ethanol-W ater hydrogen bonding 10

2.4 Two column for extractive distillation process 12

2.5 The process o f extractive distillation with salt 15

2.6 Pressure pervaporation process 21

2.7 Sweep gas pervaporation process 21

2.8 Primary building units (PBUs) in zeolites and an exampleof linking 24

2.9 Some examples of secondary building units (SBUs)present in zeolites 25

3.1 The methodology chart for adsorption and strippingprocesses 35

3.2 Experimental Set-up 38

3.3 Flow diagram of adsorption process 39

3.4 Flow diagram of stripping process 40

3.5 Calibration o f ethanol concentration using refractive index 42

4.1 Effect of temperature on adsorbed ethanol 44

4.2 Volume of adsorbed ethanol at varying temperature 45

4.3 Effect of pH on ethanol adsorption 46

4.4 The acidity o f ethanol solution affecting the linkingbetween ethanol and water molecules 47

4.5 Effect of pH on ethanol volume 47

4.6 Effect of time on ethanol concentration 49

4.7 Volume of ethanol adsorbed at different adsorption time 50

4.8 Effect of time on concentration o f stripped ethanol in stripping process 51

4.9 Effect of time on the stripped ethanol volume in stripping process 52

4.10 Effect of temperature on the concentration o f stripped ethanol in stripping process. 53

4.11 Effect of temperature on the volume of stripped ethanol in

stripping process 54

LIST OF SYMBOLS

M - Adsorbent capacity

S - Adsorbent selectivity

0 - Efficiency o f adsorbent

Al - Aluminum

Co - Cobalt

CO2 - Carbon Dioxide

Ge - Germanium

GE - Gibbs Energy

H2O - W ater

HCl - Hydrochloric Acid

Mg - Magnesium

Mn - Manganese

N 2 - Nitrogen

NaA - Zeolite

NaOH - Sodium Hydroxide

nD - refractive index

-N -H - Nitric Group

NOx - Nitrogen Oxygen Compound

O2 - Oxygen

-O -H - Hydroxide Group

P - Phosphor

Pi - Pressure of component i

pH - Magnitude o f acidity

Psat - Saturated Pressure

R - Gas Constant

S - Solvent

Si-O-H - Silanol groups

SOx - Sulfur Oxygen Compound

T - Temperature

X - Mole / Mass Fraction in Liquid Phase

Xi - Mole Fraction of i Component in Liquid phase

Y - Mole / Mass Fraction in Gas Phase

Zn - Zinc

LIST OF ABBREVIATIONS

ACN - Acetonitrile

C2H5OH - Ethel alcohol ( Ethanol )

DMF - Dimethethylformanide

E10 - 10 percent ethanol and 90 percent gasoline

E85 - 85 percent ethanol and 15 percent gasoline

HPLC - High Performance Liquid Chromotography

MTBE - Methyl t-butyl ether

NMP - N-methyl-pyrrolidone

PDMS - Polydimethylsiloxane

PDMS - PS IPN polydimethysiloxane-polystyrene interpenetrating polymer network

PVA - Polyvinyl acetate

SBUs - Secondary Building Units

THF - Tetrahydrofuran

VLE - Vapor Liquid Equilibrium

LIST OF APPENDECIES

A PPEN D IX T IT L E PA GE

A Data for refractometer 67

A.1 Data for standard ethanol/water solutions link between nDand Percent o f ethanol for 1st batch 67

A.2 Data for standard ethanol/water solutions link between nDand percent of ethanol for 2nd batch. 68

B Data of ethanol percent at various temperatures o f adsorption 69

B.1 Data of ethanol concentration and volume at different temperaturefor adsorption process for 1st and 2nd batch 69

B.2 Data of average ethanol concentration and volume at different

temperature o f adsorption process 69

C Data of ethanol percent at various adsorption times 70

C.1 Data of ethanol concentration and volume at different timefor adsorption process for 1st and 2nd batch 70

C.2 Data of average ethanol concentration and volume at differenttime o f adsorption process 70

D Data of ethanol percent at various pH of feed solution 71

D.1 Data of ethanol concentration and volume at different pH offeed for adsorption process for 1st and 2nd batch 71

D.2 Data of average ethanol concentration and volume at differentpH of feed of adsorption process 71

E Data of ethanol percent at various stripping time 72

E.1 Data of ethanol concentration and volume at different time for stripping process for 1st and 2nd batch 72

E.2 Data of average ethanol concentration and volume at differenttime of stripping Process 72

F Data of ethanol percent at various temperatures o f stripping 73

F.1 Data of ethanol concentration and volume at differenttemperature for stripping process for 1st and 2nd batch 73

F.2 Data o f average ethanol concentration and volume at differenttemperature o f stripping process 73

C H A PT ER 1

IN TR O D U CTIO N

1.1 B ackground of the Study

Fuel grade bioethanol production has gained interest globally because of its

use as fuel oxygenate and as alternative fuel. Bioethanol is repeatedly being utilized

as a fuel oxygenate instead o f methyl t-butyl ether (MTBE) or fuel additive to

increase the octane number. Fermentation process is the main way to produce

bioethanol fuel from the sugar; although there are many ways to manufacture ethanol

by the chemical process or as a by-product o f some chemical processes (Vane, 2005).

The main sources o f bioethanol are sugar from crops including corn, maize and

wheat crops. Recently, there is more research has been done to produce bioethanol

from lignocellulosic biomass such as from oil palm biomass, woods and plant waste.

Bioethanol or chemically called ethyl alcohol (C2H5OH) is a clear colorless

liquid, low in toxicity, biodegradable, and makes little pollution to the environment if

spilt (O 'Brien and Craig, 1996). Burning o f ethanol produces water and carbon

dioxide. Bioethanol is applicable alternative fuel and virtually limitless potential for

growth. The production of alternative fuel is due to the limitation of fossil fuel such

as crude oil, hence the going towards more different sources of renewable of energy.

Generally, ethanol is going to be one o f alternative environmental friendly

fuel friendly and harmless to the environment than gasoline. Using ethanol as a fuel

for vehicles introduce benefit to minimize emissions o f carbon dioxide and carbon

monoxide, the same or lower emissions levels o f hydrocarbon and oxides of

nitrogen. For example E85 fuel is produced by blending of 85 percent ethanol and

15 percent gasoline, this blending decreases the consumption of fossil fuel and has

lower percent o f volatile components than pure gasoline, leading to the decrease of

emissions occurred by evaporation. Low percentage o f blending ethanol with

gasoline, such as 90 percent gasoline and 10 percent ethanol (E10) leads to reduce

emissions of carbon monoxide and improving the octane number for the fuel. Fuel

o f the vehicles becomes more flexible by using (E85). In United States, the use of

E85 is growing due to the increase number of fuel stations (ethanolrfa, 2013).

1.2 Problem Statem ent

Mostly, the production of bioethanol involves pretreatment stage with acid

or base solution, hydrolysis either with sulphuric acid, and fermentation with yeast

broth. Usually, the end stream contained ethanol, and impurities. There are many

techniques to separate ethanol from ethanol / water mixture such as distillation

process, extractive distillation with Salt, solvent liquid or with ionic liquid,

pervaporation process and adsorption process. It is critical to find the most suitable

method to separate ethanol from the impurities that requires less energy, simple and

low cost, yet, is efficient.

The difficulty o f separation o f ethanol from water (broth o f fermentation) is

come from the generation of an azeotrope in the mixture at certain temperature. This

azeotropic behavior appears because of presence o f hydrogen bonds. Hydrogen

bonds lead to interaction between molecules o f ethanol and water. This interaction

makes separation of ethanol become difficult. The Azeotropic point appears at

composition o f 95.6(wt) % for ethanol and the rest is water. Traditional technique

like distillation consumes high energy. Hence, adsorption techniques will be studied

as it is expected to give good separation at low cost, especially for low ethanol

concentration in water and impurities stream.

1.3 Objectives

In general, this work is aimed to study the efficiency o f the adsorption

technique to achieve good purity o f bioethanol production by manipulating the

operating condition, such as time of adsorption, time of stripping, mass ratio

ethanol/adsorbent (capacity o f adsorbent), temperature and acidity o f the feed.

Following are the objectives o f this study.

i) To study the effect o f operating conditions on the efficiency o f the

adsorption technique to achieve good purity o f bioethanol.

ii) To evaluate the best operating conditions for adsorption of model

bioethanol mixture.

iii) To evaluate the best operating conditions of stripping process, i.e., air

temperature and time.

1.4 Scope

The simulated mixture o f bioethanol has concentration 10wt%.

Sepabeads207 was used in the adsorption and stripping processes. The operation

parameters o f adsorption such as time o f adsorption (5 - 25 min.), temperature

(20 - 40 °C) and acidity of the feed (4-7) were varied and evaluated the best

conditions. The stripping process parameters were studied time (15- 35 min.) and

temperature (80-95 °C). The yield of bioethanol was determined by direct volume

measurement whereas the purity o f bioethanol was analysed by gas chromatography

and refractometer.

Delgado, J., Uguina, M., Sotelo, J., Agueda,V., Alvaro,G. and Roldan, A.(2012).

Separation of Ethanol-Water Liquid Mixtures by Adsorption on Silicalite.

CAew/ca/ EMg/'^eer/'^g JoMr^a/. 180, 137 - 144.

ETHANOLRFA. (2013).http://www.ethanolrfa.org. (Assessed on October 2013).

Fragoulis, D., Chaniotakis, E. and Stamatakis, M.G. (1997). Zeolitic Tuffs of

Kimolos Island, Aegean Sea, Greece and Their Industrial Potential. Cewe^f

& Co^crefe PesearcA. 27, 889-905.

Gao, Z., Wang, S., Sun, Q. and Zhang, F. (2003). Isobaric Phase Equilibria of the

System1-butanol + water Containing Penicillin G Potassium Salt at Low

Pressures. E/M/' PAase E M/'A' r/'a. 214, 137 - 149.

Gu, F. and Hou, Y. (2000). Salt Effects on the Isobaric Vapour-Liquid Equilibrium

for Four Binary Systems. JoMma/ o / CAew/ca/ E^gmeermg Dafa. 45, 467 - 470.

Huang, H-J., Ramaswamy, S., Tshirner, U.W. and Ramardo, B.V. (2008). A Review

of Separation Technologies in Current and Future Biorefiners. <S*eparaf/'o a ^

PMr//?cafo TecA^o/ogy. 62, 1 - 21.

Huang, R. Y. M., (1991). Pervaporation Membrane Separation Processes. Mew&ra^e

<S*c/'e ce a ^ TecA^o/ogy ^er/'es. 20(1), 109 - 111

IZA-STRUCTURE. (2013). Affp.//www./'za-.sfrMcfMre.org/Wafa&a.ye.y.(Assesed on

November 2013).

Kato, M., Sato, T. and Hirata, M. (1971). Measurement of Salt Effect on Vapour-

Liquid Equilibria by Bubble and Condensation Point Method. JoMr^a/ o /

CAew/ca/ E^gmeermg o/Japa^. 4, 308 - 311.

Komaromine, M. K., Loksa, G., Csereklye, K. E., Bardoczyne, E. S. and Kallai, S.

(2008). Use of Zeolite to Improve Soil Amelioration and Takes Effects on

Microclimate. Cerea/ PesearcA CowwMw'caf/'om*. 36, 1783 - 1786.

Lee, L-S., and Huang, M-Y. (2000). The Vapour-Liquid Equilibrium of Ethanol-

Water Mixture in the Presence of Benzyltriethylammonium Chloride Salt at

Atmospheric Pressure. CAew/ca/ E^gmeermg CowwM /'caf/'o . 180(1), 19 - 38.

Malik, R. K, Ghosh, P. and Ghose, T. K. (1983). Ethanol Separation by Adsorption-

Desorption. B/otecAno/ogy and B/oeng/neer/ng. 25(9), 2277-2282.

O'Brien, D. J. and Craig, J. C. (1996). Ethanol Production in a Continuous

Fermentation/Membrane Pervaporation System. ^ppAe^ M/cro^/o/ogy

P/ofecA^o/ogy. 44, 699 - 704.

Tang, L. Q., Shi, L., Bonneau, C., Sun, J. L., Yue, H. J., Ojuva, A., Lee, B. L.,

Kritikos, M., Bell, R. G., Bacsik, Z., Mink, J. and Zou, X. D. (2008). A Zeolite

Family with Chiral and Achiral Structures Built From the Same Building Layer.

^afMre Mafer/'a/s. 7, 381- 385.

Vane, L. M. (2005). Pervoporaf/o^-M ew^ra^e Process ybr P/oefAa^o/ Recovery,

<S*o/ve f DeAy^raf/'o^ Co^faw/'^a^f Pewova/. Case Study, 1 - 5.

Veera, R. B., Subba, R. S., Damodara, R. M., Narasimha, R. M. and Ayyanna, C.

(2006). Optimization o f Fermentation Conditions for the Production of Ethanol

from Sago Starch by Co-immobilized Amyloglucosidase and Cell of

Zymomonas MobilisUsing Response Surface Methodology. Phzywe

M/'cro^/'a/ TecA^o/ogy.

38, 209 - 214.

Verhoef, A., Figoli, A., Leen, B., Bettens, B., Drioli, E., Van der and Bruggen, B.

(2008). Perfomance o f a Nanofiltration Membrane for Removal of Ethanol from

Aqueous Solutions by Pervapoaration. ^ e p a r a f o PMr/^caf/'o^ TecA^o/ogy.

60, 54 - 63.

Watanabe, Y., Yamada, H.,Tanaka, J., Komatsu, Y. and Moriyoshi, Y. (2004).

Ammonium Ion Exchange of Synthetic Zeolites: The Effect o f Their Open-

Windows Sizes, Pore Structures, and Cation Exchange Capacities. ^ e p a r a f o

<S*c/'e ce TecA^o/ogy. 20P7- 2704.

Zhigang, L., Biaohua, C. and Zhongwei, D. (2005). ^pec/'a/ D/sf/7/af/o^ Process.

British Library, U.K: Elsevier Publisher.

Zhou, W. Z. (2008). Microscopic Study of Crystal Defects Enriches Our Knowledge

o f Materials Chemistry. JoMr^a/ o/^Mhfer/a/s CAew/sfry. 18, 5321- 5325.