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• Lee Jian

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Process and Plant Design 1 • Group 11 • Members: Andy Tan Eng Tat Leonard Tan Jian Zheng Lim Su Wei Leow Kok Chung Ong Ching Yeh

Production Of Ethyl Acetate

Purpose of The Presentation • To investigate the current problems or issues pertaining to the ethyl acetate production process and formulate solutions in overcoming the problems • Three parts - Task 1,2,3 • Task 1 – Market Demand, Location, Pathway • Task 2 – Process Description, Preliminary Process Synthesis, Heuristics • Task 3 – Unit Operation and Simulation

Task 1 Outlines 1. 2. 3. 4. 5. 6. 7.

Properties of Ethyl Acetate Applications of Ethyl Acetate Problem Statement Global Market of Ethyl Acetate Choosing the Right Plant Location Selecting the Most Promising Reaction Pathways Drawbacks and Improvements of Esterification Reaction

Properties of Ethyl Acetate • • • • • • •

Organic Compound Formula C4H8O2 Colorless Volatile Flammable Fruit Smell Slightly Soluble In Water/ Soluble In Organic Solvents

Applications of Ethyl Acetate • Artificial Fruit Enhancer

Applications of Ethyl Acetate • Solvent/Thinner

Applications of Ethyl Acetate • Flexible Packaging

Problem Statement Two Aspects 1. Business • To Find The Most Promising Pathway • Maximize Profits • Minimize Production Cost • Sustainability of Market 2. Social and Moral • Environmental Concerns

Global and Regional Markets of Ethyl Acetate • 2005-2013

Global Markets of Ethyl Acetate

Choosing The Right Plant Location Consider following factors 1. Political Stability and Government Policies 2. Availability of Raw Materials 3. Connectivity/Transportation 4. Power and Water Supply 5. Waste Management Disposal 6. Flood and Fire Prevention 7. Human Resources (Skilled/Unskilled) 8. Proximity to The Market

Locations Considered 1. Yanbu Industrial City, Yanbu Al-Bahr, Saudi Arabia (THE SELECETED LOCATION) 2. Mount Kuring-Gai, New South Wales, Australia 3. YanTianGang Free Trade Zone, Yantian District, Shenzhen City, China

Why Yanbu Industrial City in Saudi Arabia ? • Petroleum derived raw materials are cheap in Saudi Arabia • Shortage of ethyl acetate supply in Saudi Arabia • Strategic Location(Located along Red Sea and near Suez Canal) which can cater for Western Asia and Europe markets • China’s market is saturated • Expensive labor cost in Australia

Yanbu Industrial City, Yanbu Al-Bahr Saudi Arabia

Yanbu Industrial City, Yanbu Al-Bahr Saudi Arabia

Selecting the Most Promising Reaction Pathways 1. 2. 3. 4. 5.

Esterification (The Selected Pathway) Tischenko Reaction Addition of Ethylene and Acetic Acid Dehydrogenation of Ethanol Oxidation of Ethanol

Esterification •

CH CH OH

+ CH COOH



.



CH COOCH CH

+ H O( )

• Reversible reaction • Remove water by-product to drive reaction to the right Advantages

Disadvantages

• Ease of raw material availability • Non-toxic, less harmful raw materials • Less cost of catalyst

• Ethanol conventional air pollutant • Water as waste product impeding reaction eventually

Tishchenko Reaction •





‘

• Two equivalents of acetaldehydes Advantages

Disadvantages

• Raw material acetaldehyde is not costly

• Acetaldehyde is a very toxic substance

Addition of Ethylene and Acetic Acid • Avada • H C = CH

+ CH COOH





CH COOCH CH

Advantages

Disadvantages

• Energy efficient, environmentally friendly

• Ethylene requires special safety and fire fighting facilities

Oxidation of Ethanol • C H OH + O

CH CHO + H O

• CH CHO + O • C H OH + CH COOH

CH COOH CH COOC H + H O

Advantages

Disadvantages

• Availability of raw material ethanol

• Weak metal support interaction • High risk of explosion requires larger reactor size and costs

Dehydrogenation of Ethanol • Carried out in four process stages • 2CH CH OH g → CH COOCH CH g + 2H g Advantages

Disadvantages

• Ethanol is easily available

• Complicated Unit Operations • Acetaldehyde has high toxicity

Why Esterification is Chosen ?

Why Esterification is Chosen? 6 Points • Raw Material • Safety, Health and Environment • Utilities • Simplicity of The Process • Operating Conditions • Conversion and Selectivity

Why Esterification is Chosen? • Raw Materials for Tishchenko Reaction cannot be found in Saudi Arabia • Technology of dehydrogenation of ethanol is still developing • Catalysts used in oxidation of ethanol are expensive despite the reaction gives highest profit

Why Esterification is Chosen? • Avada process has short reaction rate and depends highly on the performance of catalysts • Avoid usage of Acetaldehyde as raw material as it is toxic and very harmful

Drawbacks and Improvements of Esterification Reaction • Heterogeneous catalyst replaces homogeneous catalyst • Reactive Distillation is suggested for Esterification Reaction • Heuristic studies are conducted to avoid repeating the same mistakes in the future

Drawbacks and Improvements of Esterification Reaction Reactive Distillation • Shifting chemical equilibrium and thus results in an increase of conversion of raw material by simultaneous reaction and separation product. • Suppression of side reaction and thus higher purity of desired product can be obtained. • Utilization of heat of reaction (esterification is an exothermic reaction) for mass transfer operation. • These features on the process can further lead to economic benefits which are shown below: • Lower capital investment (reactive distillation combined both the function of reactor and distillation column) • Lower energy cost (heat generated from the process in used as the mass transfer purpose) • Higher product yield (Suppression of water by-product )

Task 2 Outlines 1. Process Description 2. Preliminary Process Synthesis 3. Heuristics

Process Description • EtOH + HAc ⇌ EtAc + H2O • Azeotropic mixture • Total of 4 azeotropes Mixtures

Compositions (mole fraction)

Temperature (oC)

EtOH/H2O

(0.9037, 0.0963)

78.18

EtAc/EtOH

(0.6885, 0.3115)

71.81

EtAc/H2O

(0.6885, 0.3115)

70.37

EtAc/EtOH/H2O

(0.1126, 0.5879, 0.3085)

70.09

Compositions and Temperatures for EtAC System

Ternary Azeotrope Diagram

Process Description • • •

Single double-feed reactive distillation column incapable to produce high purity EtAc Two-column design with decanter Decanter as liquid-liquid separator

Preliminary Process Synthesis • Step 1: Eliminate Differences in Molecular Types • Step 2: Distribution of Chemicals • Step 3: Eliminate Differences in Composition • Step 4: Eliminate Differences in Temperature, Pressure and Phase • Step 5: Task Integration

Step 1: Eliminate Differences in Molecular Types Reaction

Pathway 1

Pathway 2

Pathway 3

Pathway 4

Pathway 5

Availability

Easily

Not easily

Easily

Available

Available

available

available

available

0.3566

0.2951

0.3221

0.6667

0.6873

Corrosive

Highly toxic

Corrosive

Flammable

Flammable

and

and

and

raw material

raw material

flammable

flammable

flammable

raw material

raw material

raw material

Gross Profit ($/Ib EtAc)

Safety Consideration

• Reaction Pathway 1 (Esterification): CH3CH2OH + CH3COOH → CH3COOCH2CH3 + H2O • Reaction Pathway 2 (Tishchenko Reaction): CH3CHO → CH3COOCH2CH3 • Reaction Pathway 3 (Avada): C2H4 + CH3COOH → CH3COOCH2CH3 • Reaction Pathway 4 (Oxidation of Ethanol): CH3CH2OH + CH3COOH → CH3COOCH2CH3 + H2O • Reaction Pathway 5 (Dehydrogenation of Ethanol): 1 C H OH + O 2 1 CH CHO + O 2 C H OH + CH COOH

CH CHO + H O CH COOH CH COOC H + H O

Step 2: Distribution of Chemicals • Assumptions: 1) Conversion of acetic acid, HAc is 100% 2) Operation time for plant set to 8400 hours per year; 350 days per year: 6012.35 kg/hr for 10,000 tonnes of product 3) Outlet composition of the reactive distillation column is near minimum ternary azeotrope 4) Outlet composition of the stripper is obtained from the process design of the stripper 5) Components in the decanter is in equilibrium

• Overall balance:

• • • •

A = 3471.582068 kg Ethanol/hr B = 4198.91034 kg HAc/hr C = 1658.142408 kg/hr Ethyl acetate product at 6012.35 kg/hr

Step 3: Eliminate Differences in Composition • Reactive distillation column for reversible chemical reaction • Simultaneous separation of products and recycle of incompletely consumed reactants

Part of Process Flow Diagram – Top of RDC and Decanter

Step 4: Eliminate Differences in Temperature, Pressure and Phase

Process Flow Diagram

• Reboiler heated up before feed stream is fed to reboiler • Top RDC product as vapour passes through condenser and changed to liquid form • Liquid phase to decanter • Manipulating heat input to stripper to maintain same temperature of bottom temperature to stripper • Final product stream passed through cooler to reduce temperature of final product

Step 5: Task Integration Condenser

Decanter

Reactive Distillation

Reboiler

Process Flow Diagram Stripping Tower

• Reactive Distillation (RD) Column and Condenser Separation being done; consist of two sections:1) Reactive section 2) Rectifying zone • • • •

Stripper and Condenser Decanter Cooler Control Valves

Heuristics • Heuristic 1: “Select raw materials and chemical reactions to avoid, or reduce, the handling and storage of hazardous and toxic chemicals.” • Heuristic 2: “Use an excess of one chemical reactant in a reaction operation to completely consume a second valuable, toxic, or hazardous chemical reactant.” • Heuristics 8: “For reversible reactions, especially, consider conducting them in a separation device capable of removing the products, and hence, driving the reactions to the right. Such reaction-separation operations lead to very different distributions of chemicals.”

• Heuristics 9: “Separate liquid mixtures using distillation and stripping towers, and liquid-liquid extractors, among similar operations, and so on, with the unreacted chemicals recovered in a liquid phase and recycled to the reaction operation.” • Heuristic 22: “For less exothermic heats of reaction, circulate reactor fluid to an external cooler, or use a jacketed vessel or heating coils. Also, consider the use of intercoolers between adiabatic reaction stages.”

Task 3 Outline • Mass and energy balance • Hysys simulation

Mass Balance

Stream number

1 Acetic acid feed to C001

2 Ethanol feed to C001

3 RDC top product before condense r E002

Liquid

Liquid

Vapor

4 5 6 7 8 9 10 11 12 RDC top Organic Organic Organic Aqueous Stripper Stripper Ethyl Ethyl product part feed to reflux to product top top acetate acetate after from stripper C001 from product product product product condens decante C002 FL001 before after before after er E002 r FL001 condenser condenser cooler cooler E003 E003 E005 E005

Name of the stream

Phase

Mass flow rate (kg/hr)

Liquid

Liquid

Liquid

Liquid

Liquid

Vapor

Liquid

Liquid

Liquid

3471.58207 4198.91034 25940.15 25940.1 33310.4 16655.21 16655.21 1658.142 9028.4097 9028.4097 6012.35 6012.35

wt%

wt%

wt%

wt%

wt%

wt%

wt%

wt%

wt%

wt%

wt%

wt%

Ethyl acetate

0

0

82.6

82.6

92.03

92.03

92.03

1.58

95.77

95.77

99.5

99.5

Water

1

4.5

9

9

2.12

2.12

2.12

95.88

1.93

1.93

0

0

Ethanol

0

95.5

8.4

8.4

4.1

4.1

4.1

2.5

2.3

2.3

0.5

0.5

Acetic acid

99

0

0

0

0

0

0

0

0

0

0

0

Energy Balance

Enthalpy The enthalpy for each stream is given by

Hˆ T ,i  Hˆ

 f , 298.15 K



T

298.15 K

C p ,i dT

Stream

1

2

3

Acetic Acid Ethanol RDC top before Feed Feed condenser 1 Phase

Liquid

Liquid

Temperature (K) 298.15 298.15

4

RDC top after condenser 1

5

6

Organic part Organic feed from Decanter to Stripper

Vapour

Liquid

Liquid

Liquid

342.8

313.15

313.15

313.15

-277.605

-277.755

-277.755

-277.755

-450.1

-457.7

-457.7

-457.7

-284.316

-285.332

-285.332

-285.332

Enthaply (kJ/mol) Ethanol

-277.63

Acetic Acid -486.18

Ethyl Acetate Water

-285.84 -285.84

Stream

7 Organic Reflux

8

9

Aqueous Stripper Top Product Product before condenser

10 Stripper Top Product after condenser

11

12 Ethyl Acetate Ethyl Acetate Product after before cooler cooler

Phase

Liquid

Liquid

Vapour

Liquid

Liquid

Liquid

Temperature (K)

313.5

313.15

343.75

313.15

353.15

308.15

-277.755

-277.755

-277.615

-277.755

-277.47

-277.6105

-457.7

-449.2

-457.7

443.1

-460.15

-285.332

-284.1

-285.332

-283.977

-285.5

Enthaply (kJ/mol) Ethanol Acetic Acid Ethyl Acetate -457.7 Water

-285.332

Heat Duties Inlet Outlet Streams Streams

Difference in Enthaply (kJ/mol)

Heat Duty (kW)

Reboiler of RD

1,2,7

3

??

???

Condenser of RDC

3

4

??

???

Reboiler of Stripper

6

9,11

??

???

Condenser of Stripper

9

10

??

???

Cooler

11

12

??

???

Aspen HYSYS Simulation

Hysys simulation (proposed flowsheet)

Hysys simulation

Conclusion • • • • • •

Demand location Pathway Preliminary process synthesis Mass balance Simulation