Sulfolane aromatic extraction

Ethylbenzene is separated from mixed xylenes by fractionation using 360 trays and a high reflux ratio. Ethylbenzene is separated from the closest isomer paraxylene whose normal boiling point is only 3.90°F higher. The average relative volatility between ethylbenzene and paraxylene in the fractionation is about 1.06. The fractionator feed is entirely Cg aromatics which are prepared by the extraction of powerformate by the sulfolane process and by fractionation of the aromatic extract. 

The reformate produced in the OCR Platforming unit is sent to a debutanizer column, which strips off the light ends. The debutanizer bottoms are sent to a reformate splitter (3). The C7 fraction from the overhead of the reformate splitter is sent to a Sulfolane unit (4). The C8+ fraction from the bottom of the reformate splitter is sent to a xylene fractionation section. The Sulfolane unit extracts the aromatics and then individual high-purity benzene and toluene products are recovered in a BT fractionation section (5 6). 

Low capital investment and low operating costs—about 30% lower than sulfolane liquid-liquid aromatics extraction process... 

UOP LLC, A Honeywell Co. Aromatics extraction Reformate, pyrolysis gasoline or coke oven light oil UOP Sulfolane process recovers high-purity C -Cg aromatics from hydrocarbon mixtures, such as reformed petroleum naphtha (reformate), pyrolysis gasoline (pygas), or coke oven light oil (COLO), by extractive distillation with or without liquid-liquid extraction 139 NA... 

UOP LLC, A Honeywell Co. Aromatics extractive distillation BT Reformate UOP Extractive Distillation (ED) Sulfolane process recovers high-purity aromatics from hydrocarbon mixtures by extractive distillation. Extractive Distillation is a lower cost, more suitable option for feeds rich in aromatics containing mostly benzene and/or toluene 139 2010... 

The rotating-disk contactor (RDC), developed in the Netherlands (158) in 1951, uses the shearing action of a rapidly rotating disk to interdisperse the phases (Eig. 15b). These contactors have been used widely throughout the world, particularly in the petrochemical industry for furfural [98-01-1] and SO2 extraction, propane deasphalting, sulfolane [126-33-0] extraction for separation of aromatics, and caprolactam (qv) [105-60-2] purification. Columns up to 4.27 m in diameter are in service. An extensive study (159) has provided an excellent theoretical framework for scale-up. A design manual has also been compiled (160). Detailed descriptions and design criteria for the RDC may also be found (161). 

Gycloaliphatics and Aromatics. Cychc compounds (cyclohexane and benzene) are also important sources of petrochemical products (Fig. 14). Aromatics are ia high concentration ia the product streams from a catalytic reformer. When aromatics are needed for petrochemical manufacture, they are extracted from the reformer s product usiag solvents such as glycols (eg, the Udex process) and sulfolane. 

Aromatic Hydrocarbons. Sulfolane is used principally as a solvent for extraction of benzene, toluene, and xylene from mixtures containing aHphatic hydrocarbons (33—37). The sulfolane process was introduced in 1959 by SheU Development Company, and that process is Hcensed by Universal OH Products. A sulfolane extraction process is also Hcensed by the Atlantic Richfield Company. In 1994, worldwide consumption was estimated at ca 6974 t/yr of sulfolane for 137 sulfolane extraction units (see Bix processes Extraction, liquid-liquid Xylenes and ethylbenzene). 

In general, the sulfolane extraction unit consists of four basic parts extractor, extractive stripper, extract recovery column, and water—wash tower. The hydrocarbon feed is first contacted with sulfolane in the extractor, where the aromatics and some light nonaromatics dissolve in the sulfolane. The rich solvent then passes to the extractive stripper where the light nonaromatics are stripped. The bottom stream, which consists of sulfolane and aromatic components, and which at this point is essentiaHy free of nonaromatics, enters the recovery column where the aromatics are removed. The sulfolane is returned to the extractor. The non aromatic raffinate obtained initially from the extractor is contacted with water in the wash tower to remove dissolved sulfolane, which is subsequently recovered in the extract recovery column. Benzene and toluene recoveries in the process are routinely greater than 99%, and xylene recoveries exceed 95%. 

M-iscellaneousFxtractions. Additional extractive separations using sulfolane involve (/) mercaptans and sulfides from sour petroleum (45) (2) /-butylstyrene from /-butylethjlbenzene (46) (J) mixtures of close boiling chlorosHanes (47) and (4) aromatics from kerosene (48—50), naphtha (49,51—53), and aviation turbine fuel (54). 

Sulfur dioxide acts as a dienophile ia the Diels-Alder reaction with many dienes (253,254) and this reaction is conducted on a commercial scale with butadiene. The initial adduct, sulfolene [77-79-2] is hydrogenated to a solvent, sulfolane [126-33-0] which is useful for selective extraction of aromatic hydrocarbons from... 

Extraction and Extractive Distillation. The choice of an extraction or extractive distillation solvent depends upon its boiling point, polarity, thermal stabiUty, selectivity, aromatics capacity, and upon the feed aromatic content (see Extraction). Capacity, defined as the quantity of material that is extracted from the feed by a given quantity of solvent, must be balanced against selectivity, defined as the degree to which the solvent extracts the aromatics in the feed in preference to paraffins and other materials. Most high capacity solvents have low selectivity. The ultimate choice of solvent is deterrnined by economics. The most important extraction processes use either sulfolane or glycols as the polar extraction solvent. 

Benzene, toluene, xylenes (BTX), and ethylbenzene are obtained mainly from the catalytic reforming of heavy naphtha. The product reformate is rich in Ce, C7, and Cg aromatics, which could be extracted by a suitable solvent such as sulfolane or ethylene glycol. 

Liquid solvents are used to extract either desirable or undesirable compounds from a liquid mixture. Solvent extraction processes use a liquid solvent that has a high solvolytic power for certain compounds in the feed mixture. For example, ethylene glycol has a greater affinity for aromatic hydrocarbons and extracts them preferentially from a reformate mixture (a liquid paraffinic and aromatic product from catalytic reforming). The raffinate, which is mainly paraffins, is freed from traces of ethylene glycol by distillation. Other solvents that could be used for this purpose are liquid sulfur dioxide and sulfolane (tetramethylene sulfone). 

The sulfolane process is a versatile extractant for producing high purity BTX aromatics (benzene, toluene, and xylenes). It also extracts aromatics from kerosines to produce low-aromatic jet fuels. 

Sulfolane is a water-soluble biodegradable and highly polar compound valued for its solvent properties. Approximately 20 million pounds of sulfolane are consumed annually in applications that include delignification of wood, polymerization and fiber spinning, and electroplating bathes.It is a solvent for selectively extracting aromatics from reformates and coke oven products. 

Sulfolane A process for removing aromatic hydrocarbons from petroleum fractions by liquid-liquid extraction using sulfolane (tetramethylene sulfone tetrahydrothiophene-1,1-dioxide) at approximately 190°C. Developed by Shell Development Company in 1959 and first commercialized in 1962 now licensed through UOP. It replaced the Udex process. Sulfolane is used for another purpose in the Sulfinol process. 

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