Group Members

Syed Muhammad Obaid Ur RehmanCH-018 Hosh Muhammad ShiekhCH-025 Syed Muhammad Shaheer FayyazCH-042 Syed Zaki Haider NaqviCH-061

BTX SEPARATION

BENZENE

Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6.

Benzene is a natural constituent of crude oil, and is one of the most basic petrochemicals. Benzene is an aromatic hydrocarbon and the second [n]-annulene ([6]-annulene), a cyclic hydrocarbon with a continuous pi bond. It is sometimes abbreviated Ph–H. Benzene is a colorless and highly flammable liquid with a sweet smell. Because it is a known carcinogen, its use as an additive in gasoline is now limited, but it is an important industrial solvent and precursor to basic industrial chemicals including drugs, plastics, synthetic rubber, and dyes.

STRUCTURE OF BENZENE

TOLUENE

Toluene, formerly known as toluol, is a clear, water-insoluble liquid with the typical smell of paint thinners. It is a mono-substituted benzene derivative, i.e., one in which a single hydrogen atom from the benzene molecule has been replaced by a univalent group, in this case CH3.

It is an aromatic hydrocarbon that is widely used as an industrial feedstock and as a solvent. Like other solvents, toluene is sometimes also used as an inhalant drug for its intoxicating properties; however, inhaling toluene has potential to cause severe neurological harm.[1][2] Toluene is an important organic solvent, but is also capable of dissolving a number of notable inorganic chemicals such as sulfur.

STRUCTURE OF TOLUENE

XYLENE

Xylene encompasses three isomers of dimethylbenzene. The isomers are distinguished by the designations ortho- (o-), meta- (m-), and para- (p-), which specify to which carbon atoms (of the benzene ring) the two methyl groups are attached. Counting the carbon atoms from one of the ring carbons bonded to a methyl group, and counting towards the second ring carbon bonded to a methyl group, the o- isomer has the IUPAC name of 1,2-dimethylbenzene, the m- isomer has the IUPAC name of 1,3-dimethylbenzene, and the p- isomer has the IUPAC name of 1,4-dimethylbenzene. The mixture is a slightly greasy, colourless liquid commonly encountered as a solvent. Several million tons are produced annually.

STRUCTURE OF XYLENE

World Wide Applications

World Wide Applications

Toluene Adhesives Manufacture Carpet adhesive solvents Electroplating Cold-

cleaning Solvents Vapor Degreasing Solvents Laboratory

ChemicalsSolvents Dilution Laboratory Chemicals

Solvents

Metal DegreasingPaint Manufacture

Hydrocarbon Solvents Paint StrippingSolvents Paint Stripping Paper Coating Solvents Pesticide Mfg (Insecticides) Solvents Insecticide

Manufacture Pharmaceuticals MfgSolvents PharmaceuticalsPrinting Solvents for Flexograph Solvents

World Wide Applications

Applications (xylene) Terephthalic acid and related

derivatives

Solvent applications

Laboratory uses

Precursor to other compounds

BTX Production Methods

1) Sulfolane process 2) Tatory process 3) Parex process 4) Toulene de-alkylation unit 5) Mixed xylene separation by

crystallization process

Process Flow Diagram

Feed or Raw Material

Naphtha

Cracked naphtha feeds such as FCC naphtha and coker naphtha are upgraded to produce chemical grade BTX (benzene, toluene, xylene with ethylbenzene) while co-producing a low sulfur gasoline of relatively high octane number. The cracked, sulfur-containing naphtha is processed by hydrodesulfurization followed by treatment over an acidic catalyst, preferably a zeolite such as ZSM-5 or zeolite beta with a hydrogenation component, preferably molybdenum. The treatment over the acidic catalyst in the second step restores the octane loss which takes place as a result of the hydrogenative treatment and results in a low sulfur gasoline product to permit a low sulfur gasoline of blending quality to be obtained with the BTX. The BTX can be extracted from the second stage effluent, preferably from a C6 -C8 fraction of this effluent.

Process Description

The key process technologies include: Reforming – The process selectively reforms

naphtha to aromatics (BTX) and high purity hydrogen.

Para-xylene Separation – The Parex™ process separates high purity para-xylene from mixed C8 aromatics isomers.

Isomerization – The Isomar™ process re-establishes an equilibrium mixture of isomers via xylene isomerization and conversion of ethyl benzene to benzene or xylenes.

Toluene and Heavy Aromatics Conversion – The UOP Tatoray™ Process disproportionates toluene and transalkylates toluene with C9/C10+ aromatics to produce benzene and xylenes.

Process Description

Toluene Selective Disproportionation – The PX Plus™ Process selectively disproportionates toluene to produce benzene and xylenes with near 90% para-xylene content, significantly above the equilibrium. 

Extractive Distillation – The Sulfolane™ process extracts benzene and toluene from the reformate using an extractive distillation flow scheme.

Thermal Hydro-Dealkylation – The THDA process converts toluene and heavier aromatics to benzene.

Aromatic Petrochemical Complex

Naphtha and gas oil is also catalytically reformed at high temperatures in the presence of catalysts to yield aromatic intermediate chemicals, such as benzene, toluene and xylene . These are liquids at ordinary temperatures and pressures and can be easily transported to desired locations where they are used as raw materials in the production of a variety of secondary chemical products as shown in Fig.

Products and By Products

Industries Producing and Consuming BTX

Producers National RefineryUnder Development of BTX plant BYCO Refinery Attock RefineryConsumers Tufail Chemicals