Literature Survey Mohammed Al-Mohsen Yaqoub Bader Ali Mohammed Al-Faraj Nasser Al-Ajmi Ali Shamsaldein

Outlines: Introduction Uses of Ethylbenzene: Reactions and Thermodynamic Catalyst used Process technology of producing ethylbenzene Major equipments Conclusions

Introduction: Ethylbenzene is an organic compound used almost exclusively as an intermediate in the production of Styrene. It’s chemical formula is C 6 H 5 CH 2 CH 3 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:

Uses of Ethylbenzene: 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 Ethylene Benzene Ethylbenzene Styrene. ABS Polystyrene

Reactions and Thermodynamic: Ethylbenzene is produced via a catalytic process which selectivity dehydrogenates the ethyl group, and can be written as following:

Successive alkylations occur, producing diethylbenzene and higher ethylated benzenes:

The polyethylbenzenes produced by successive alkylations can be transalkylated with benzene to produce additional ethylbenzene. These reactions are slower than alkylation and limited in extent by equilibrium. The following reaction is typical:

Reactions and Thermodynamic: 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.mol Liquid phase: ΔHRo= −27.19,kcal.g.mol

Minor amounts of Polyethylbenzene are produced as byproduct. Vapor phase: ΔHRo= −24.83,kcal.g.mol Liquid 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

Catalyst used: 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.

Catalyst used: Zeolite catalyst : zoelites are a microporous aluminium-silicate that have a structure that accomodates variety of cations like Na+, K+, Ca2+ and Mg 2+. Agent selectivity in zeolites depends on 1. silica to alumina ratio. 2. chemical composition of the catalyst. 3. preparation procedure.

Advantage of Zeolite 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.

Catalyst Deactivation Zeolite is deactivated by: 1. Poisoning of acid sites. 2. Blockage of the pores. 3. Coke formation.

Process technology of producing ethylbenzene: 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

Second Generation The development of second-generation vapor phase alkylation process from the first-generation: 1. The Fresh benzene is feed to the vent gas scrubber. 2. A condenser has been added to the overhead of the vent gas scrubber to generate low-pressure steam. 3. The recycled PEB stream has been routed through the flue stack of the feed process.

Third 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

Liquid phase alkylation of benzene with ethylene to produce ethyl benzene using Zeolite catalyst. liquid phase is an advanced process to produce Ethylbenzene using Zeolite catalyst that Xylene impurity is not produced and an Ethylbenzene product of superior quality is produced.

Liquid phase: The advantage of liquid phase alkylation process. 1. The alkylation reactor operate at higher pressure and low temperature. 2. The Xylene formation is minimized.

Major equipments: 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

Alkylation 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 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

Feed Heat exchange Catalyst bed Baffle

Transalkylation reactor 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.

Benzene Fractionator 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.

Ethylbenzene Column 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.

Polyethylbenzene Column 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.

Conclusions: 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 process37.5 million $ Liquid phase alkylation process is comparatively cheap.

THANK YOU FOR LISTENING AND WE ARE READY FOR THE QUESTIONS