Udex extraction process

Section, which appears every month. It also has a special section on Patents which lists new patents according to their classification. The Process Issue of the Petroleum Refiner is now carrying a special section on Petrochemical Processes. In the September 1952 issue for example, Extractive Distillation for Aromatic Recovery, Modified SO2 Extraction for Aromatic Recovery, Udex Extraction, Ethylene Manufacture by Cracking, Ethylene Production, Hypersorption, Hydrocol, Dehydrogenation (for butadiene), and Butadiene Process, were described. These descriptions include the main essentials of the process, simplified flow diagrams, and the name of the company offering it. Formerly these processes were described under the Process Section. 

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. 

Extraction (discussed in Chapter 5) uses the selective adsorption of a component in a liquid to separate specific molecules from a stream. In application extraction may be coupled with its cousins, extractive distillation and azeotropic distillation, to improve extraction efficiency. Typical refinery extraction applications involve aromatics recovery (UDEX) and lubricants processing (furfural, NMP). Extractive distillation and azeotropic distillation are rarely employed in a refinery. The only... 

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. 

The most common form of extraction involves two immiscible liquids and a solute that is soluble in both and will be recovered. Liquid-liquid extraction requires (1) extraction, (2) medium recovery, and (3) raffinate desolventizing. The Udex process is a cost-effective liquid-liquid fractionation process for the separation of aromatics from aliphatics. The extraction solvent (diethylene or triethylene glycol) is recovered by steam distillation, and the raffinate and extract streams are desol-ventized by water extraction. 

The first economic version of aromatics extraction, available industrially, was the Udex process, developed by Daw and licensed by UOP since 195Z Due to competition from new techniques, it has been practically abandoned since 1965, or its facilities altered and their production capacities increased. 

Solvent Extraction. Diethylene glycol extraction of benzene, toluene, and xylene from Platformates is one commercial method for the recovery of these materials. The process has been named the Udex process and has been described by Read (70). 

FIGURE 7.8-9 Udex process flowsheet for aromatics extraction. From Ref. 22 with perarission.)... 

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