Literature Survey Mohammed Al-Mohsen 204114376Yaqoub Bader Ali 205216198Mohammed Al-Faraj 204111522Nasser Al-Ajmi 205114238Ali Shamsaldein 204113616

Introduction

Uses of Ethylbenzene:

Reactions and Thermodynamic

Catalyst used

Process technology of producing ethylbenzene

Major equipments

Conclusions

Ethylbenzene is an organic compound used almost exclusively as an intermediate in the production of Styrene.

It’s chemical formula is

• C6H5CH2CH3

About 90% of all ethylbenzene used in the chemical industry is produced via the alkylation of benzene with ethylene.

1.Alkylation step.

2.Trans alkylation step.

3.Separation step.

Generally benzene alkylation process consists of the following three steps:

Ethylbenzene is almost exclusively used as an intermediate for the manufacture of styrene.

Styrene is processed to produce polystyrene, ABS, styrene-butadiene rubber, styrene-butadiene latexand other.

These materials are used in rubber, plastic, insulation, fiberglass, pipes, automobile and boat parts, food containers, and carpet backing.

Text

TextEthylene

Benzene

Ethylbenzene

Styrene

.

ABSPolystyrene

In the liquid-phase Alkylation Reactor Section, polymer grade Ethylene is reacted with in excess Benzene to form Ethylbenzene

Vapor phase: ΔHRo= −25.20 ,kcal.g.molLiquid phase: ΔHRo= −27.19 ,kcal.g.mol

Minor amounts of Polyethylbenzene are produced as byproduct.

Vapor phase: ΔHRo= −24.83 ,kcal.g.molLiquid phase: ΔHRo= −25.82 ,kcal.g.mol

In the liquid-phase Transalkylator Reactor Section the polyethylbenzenes (PEB) produced from the Alkylation Reaction are reacted with Benzene to form Ethylbenzene.

Liquid phase: ΔHRo= −1.3  ,kcal.g.mol

• Zeolite catalysts:

Until 1980, almost all EB was manufactured with aluminum chloride catalyst, but the ease of operation of Zeolite base process and the absence of the maintenance and environmental problem have allowed zeolite catalysts to completely replace the old catalyst.

Zeolites offer several advantages over others catalyst types.

1.Environmentally harmless and non-corrosive.

2.Alkylations do not require catalyst preparation and neutralization stages.

3.Eliminate the waste problems.

Zeolite is deactivated by:

1.Poisoning of acid sites.

2.Blockage of the pores.

3.Coke formation.

1.Vapor phase alkylation of benzene with ethylene to produce ethyl benzene using Zeolite catalyst.

I. Second Generation

II.Third Generation

2.Liquid phase alkylation of benzene with ethylene to produce ethyl benzene using Zeolite catalyst.

Vapor phase alkylation of benzene with ethylene to

produce ethyl benzene using Zeolite catalyst

Second Generation

Third Generation

The development of third-generation vapor phase alkylation process from the second-generation:

1.The prefractionater has been eliminated.

2.Only one alkylation reactor is required.

3.A smaller ethylbenzen column has been used.

4.Higher overall selectivity to ethylbenzen.

Liquid phase alkylation of benzene with ethylene to

produce ethyl benzene using Zeolite catalyst

• The advantage of liquid phase alkylation process.

1.The alkylation reactor operate at higher pressure and low temperature.

2.The Xylene formation is minimized.

• The Ethylbenzene production unit consists of two main sections, reaction section and distillation section:

I. The reaction section consist of two reactor:

1. Alkylation reactor

2. Transalkylation reactor

Fix bed reactor consists of four stages, each stage packed with Zeolite catalyst.

The operating pressure is 3.4 MPa (500 psig) and the reactor temperature is 235-270 C.

All of the benzene required for the alkylation is feed into the first stage, and the ethylene is introduced into all the four stages.

Aromatic stream

Ethylene

EB & PEP

1

2

3

4

Feed

Heat exchange

Catalyst bed

Baffle

Single stage reactor packed with Zeolite catalyst.

The reaction is carried out almost isothermally at 250°C and 3.5 Mpa (510 psig).

II.The distillation section consists of three columns:

1.Benzene Fractionator.

2.Ethylbenzene Column.

3.Polyethylbenzene Column.

Separate the reactor feed benzene from the crude EB.

Uses 36 valve trays.

The operating temperature at the top of the column is 160 C.

Separate the EB product from the PEB and heavy product.

Uses 26 valve trays.

The operating temperature at the top of the column is 152 C.

Separate PEB and EB from a heavies(residue).

The column operate under vacuum pressure.

Uses 14 valve trays.

100% of the PEB is condensed in the overhead stream.

Essentially all commercial ethylbenzene productions are consumed for the manufacture of styrene.

ProcessCapital Investment

Estimated

Second generation vapor phase process

41.6 million $

Third generation vapor phase process

39.7 million $

Liquid phase alkylation process

37.5 million $

Liquid phase alkylation process is comparatively cheap.

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