Acrylonitrile 150311102858 Conversion Gate01

8/16/2019 Acrylonitrile 150311102858 Conversion Gate01

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PRODUCTION OF

ACRYLONITRILE BY

AMMOXIDATION OFPROPYLENE


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GROUP MEMBERS

Waheed Ahmed

(2k11-ChE-09)

Adnan Rafi

(2k11-ChE-16) Ahmed Haroon

(2k11-ChE-23)

Shahzad Ali Zahid

(2k11-ChE-49)

1a


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CONTENTSIntroductionProcess DescriptionSite SelectionHazop study and EIA

1b


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Introduction

Waheed Ahmad

(2k11-Che-09)

2a


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INTRODUCTION

It was first prepared in 1893 by the French

chemist Charles

Chemical Formula C3H3N.

This pungent-smelling colorless liquid It ismonomer for the manufacture ofplastics.

It produce toxic combustion products

2b

http://en.wikipedia.org/wiki/Monomerhttp://en.wikipedia.org/wiki/Plastichttp://en.wikipedia.org/wiki/Plastichttp://en.wikipedia.org/wiki/Monomer


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PHYSICAL PROPERTIES

colorless liquid and faint characteristic odor.

Other trade names.

Acrylonitrile polymerizes explosively.

3b


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Property Value

Molecular weight 53.06Boiling point,0C 77.3 At 103.3 kPa

Critical temperature,0C

246.0

Density, g/L 806.0 At 20"C

Explosive limit at 250C, vol

%

3.05-17.0

Flash point0C -5

Freezing point,0C -83.55

Heat of polymerization,kJ/mol

-72.4

Ignition temperature, °C 481.0

Viscosity at 25°C, cP 0.34

Heat capacity, 2.094


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CHEMICAL PROPERTIES

Reactions of the Nitrile Group

Hydration and Hydrolysis

Alcoholysis

NH-HX

CH2=CHCN + ROH + HX XCH2CH2—C—OR

3d


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Reactions of the Double Bond

Diels-Alder Reactions

Hydrogenation

Halogenations Hydrodimerization.

3e


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Reactions of Both Functional Groups

Cyanoethylation Reactions (Michael-Type

Additions)

CH2=CHCN + RH RCH2CH2CN

4a


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USES AND APPLICATION

Acrylic Fibers.

Copolymer Resin ("Plastics'').

Nitrile Rubbers and Resins.

4b


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Shahzad Ali Zahid

(2k11-Che-49)


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MANUFACTURING PROCESSES

Early Processesa.Passage through ethylene cyanohydrin

The following reactions are involved:

CH2-CH2+ HCN CH2OH-CH2-CN

O

CH2OH-CH2-CN CH2=CH-CN+H2O

Temperature 200°C

Yield 90%


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b. Addition of hydrogen cyanide to acetylene

HC CH +HCN CH≡ 2=CH-CN

∆H0298≈ -175 kJ / mol

catalyst consisting of cuprous chloride and

ammonium chloride in solution in hydrochloric acid

temperature of 80 to 90°C

molar yield is up to 90 per cent

by-products are acetaldehyde, vinyl acetylene,divinylacetylene, vinyl chloride, cyano butene, lacto nitrile,

methyl vinyl ketone


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C. Passage through lactonitrile

CH3-CHO + HCN CH3CHOH-CN (10-20) °C

CH3CHOH-CN CH2-CH-CN + H2O

Yield 90 percent

D. Nitric oxide with propylene

4CH2=CH-CH3+6NO 4CH2=CH-CN + 6H2O + N2

E. From Propionitrile.

CH3CH2CN CH2= CHCN + H2


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F. From Propionaldehyde.

CH3CH2CHO + NH3 CH2 = CHCN + H20 + 2H2

G. Acrylonitrile Manufacture by ammoxidation of

propylene (Sohio Process)CH2=CH-CH3+NH3+3/2O2 CH2=CH-CN+3H2O

∆H0298 ≈ -515kJ/mol

Better quality product

Economical Its conversion in a single pass is high

Energy efficient process


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PROCESS DESCRIPTION

Raw Material

Ammonia (NH3) Air

Propylene(C3H6)

FEED RATIO= PROPENE/AMMONIA/AIR=1/1.2/9.5


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the oxygen (air) is introduced below

mixed propylene and ammonia through

“spiders” positioned above the grid

The operating pressure should be low to preventthe by-ptoducts

The residence time in the reactor is between

2 and 20 s

The main reaction isCH2=CH-CH3+NH3+3/2O2 CH2=CH-CN+3H2O

∆H0298 ≈ -515kJ/mol


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It now appears clear that this overall result can

be explained by the production of Acrolein as the

main intermediate

CH2 = CH – CH3 + O2 CH2 = CH – CHO + H2O

CH2 = CH – CHO + NH3 CH2 = CH – CH = NH + H2O

CH2= CH – CH = NH +1 /202 CH2 = CH – CN + H2O


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EFFECT OF DIFFERENT VARIABLES

ON CONVERSATION

Effect of residence time

Effect of reaction temperature

Effect of reaction pressure

Effect of Catalyst


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REACTION MECHANISM


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PROCESS FLOW DIAGRAM


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QUENCHER

It is used to remove ammonia from the reactor

effluent and low down its temperature using sulphuric

acid. It produces ammonium sulphate salt ((NH4)2SO4)

at bottom which is used as a fertilizer and the top

effluent is sent to absorber.

No. of Stages : 10

Sulphuric acid: 30% concentrated H2SO4

Bottom stream coming out of quencher mainly consists

of ammonium sulphate. This stream is further passed

into Crystallizer where crystals of ammonium sulphateare produced which is used as fertilizer.


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ABSORBER

Function of Absorber is to remove the residual gases,

containing unconverted propylene, CO2 and other VOC.

Random Packing: 5 segments of Raschig rings made up of

ceramic, diameter=0.375in

Height of each packing segment=10ft Column Diameter=5ft


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RECOVERY UNIT

Idea is to recover the useful components from the

aqueous solution like ACN, AN etc.

No. of stages: 10

Random Packing: Saddles made up of ceramic,diameter=0.5in

Total tower height=40ft

Column diameter=5ft


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CATALYST

Sohio, who initially employed bismuth phosphomolybdate

in 1967 by a mixture based on oxides of antimony and

uranium

In 1972, Sohio then returned to an iron and bismuth

phosphomolybdate doped by additions of cobalt, nickel andpotassium

The catalysts used in the process are mostly based on

mixed metal oxides such as bismuth-molybdenum oxide,

iron-antimony oxide, uranium-antimony oxide, tellurium

- molybdenum oxide etc.


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Adnan Rafi

2k11-Che-15


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HAZOP STUDY

A HAZOP survey is one of the most common and

widely accepted methods of systematic

qualitative hazard analysis.

It is used for both new or existing facilities and can

be applied to a whole plant, a production unit, or

a piece of equipment

4c


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OBJECTIVES OF A HAZOP STUDY

To identify areas of the design.

To identify and study features of the design.

To familiarize the study team.

To ensure a systematic study.

To identify pertinent design information.

To provide a mechanism for feedback.

4d


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STEPS OF HAZOP STUDY

1. Specify the purpose

2. Select the HAZOP study team

3. Collect data

4e


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5a


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HAZOP GUIDE WORDS AND

MEANINGS

5b

Guide Words Meanings

No Negation of design Intent

Less Quantitative decrease

More Quantitative increase

Part of Qualitative decrease

As well as Qualitative increase

Reverse Logical opposite of

Other than Complete substitution


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4. Conduct the study

5. Write the report

HAZOP Study of Storage Tank for Propylene

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Acrylonitrile 150311102858 Conversion Gate01