Edeleanu process

Edeleanu process An extraction process utilizing liquid sulphur dioxide for the removal of aromatic hydrocarbons and polar molecules from petroleum fractions. 

Another sulfur dioxide appHcation in oil refining is as a selective extraction solvent in the Edeleanu process (323), wherein aromatic components are extracted from a kerosene stream by sulfur dioxide, leaving a purified stream of saturated aHphatic hydrocarbons which are relatively insoluble in sulfur dioxide. Sulfur dioxide acts as a cocatalyst or catalyst modifier in certain processes for oxidation of o-xylene or naphthalene to phthaHc anhydride (324,325). 

Throughout this period Avon weed killer, a highly aromatic residue from the Edeleanu process, was about the only oil sold for purely herbicidal purposes. Meanwhile, Diesel oil was becoming popular as an automotive fuel and attempts were being made to improve its quality by removing its aromatic ingredients, a process that decreased its toxicity to plants. 

This process, commercialized by Edeleanu Gesellschaft, m.b.H., employs a solvent mixture composed of benzene and liquid sulfur dioxide. The same solvents are used in the Edeleanu process for selective solvent refining. Generally, the volume ratio of the two solvents is 80 parts of benzene to 20 parts of sulfur dioxide for dewaxing (58). For selective solvent refining the solvents are blended in the proportion of about 75% sulfur dioxide and 25% benzene. 

Edeleanu Process (Liquid Sulfur Dioxide). The forerunner of ail commercial solvent extraction processes, the Edeleanu process, has been pre-eminently successful for treating low molecular weight stocks in the kerosene-spray oil boiling range. 

An interesting modification of the Edeleanu process was the sulfur dioxide-benzene process utilized by the Union Oil Co. at Oleum, Calif. (6). In order to overcome the low solvent power of sulfur dioxide, benzene was added to the solvent. The immediate result of such addition is to reduce the selectivity of the process. However, selectivity can be improved by reducing temperatures. Therefore, a combination of reduced temperature and increased quantity of solvent provides a reasonably wide range of operating conditions in which satisfactory selectivity can be obtained. 

Edeleanu process a process for refining oils at low temperature with liquid sulfur dioxide (S02), or with liquid sulfur dioxide and benzene applicable to the recovery of aromatic concentrates from naphthas and heavier petroleum distillates. 

Edeleanu process. A solvent extraction process using liquid sulfur dioxide for the removal of undesirable aromatics from heavy lubrication oils. 

A modified Edeleanu process for the recovery of aromatic hydrocarbons from petroleum fractions has been described 65). 

In the Edeleanu process, waxy feed is mixed (Figure 9.15) in one of several reactors with urea and with recycled and fresh methylene chloride whose vaporization controls the exothermic reaction with urea. Prior to filtration, the adduct passes through a series of baffles to encourage complete reaction. After washing, the adduct is filtered from the oil, which proceeds to a stripper (to remove the methylene chloride) and then to product storage. The separate adduct stream from the filter is decomposed by steam at 75°C, then sent to a separator and subsequently stripped of solvent to yield the n-parafflns. The dewaxed oils disengage from the aqueous phase in a separator. 

Edeleanu Process. The first commercially successful application of extraction of petroleum-refining processes was established by Edeleanu (38, 39), who extracted aromatic hydrocarbons from kerosenes with liquid sulfur dioxide to improve their burning qualities. The solvent is extremely selective for this purpose and acts without chemical reaction. 

Fig. 11.1. Simplified flowsheet of Edeleanu process for kerosenes. [Adapted from Defize (33).]...

Recovery of Aromatics. A most interesting adaptation of the Edeleanu process was used during the Second World War for production of toluene and other aromatic hydrocarbons for high-octane-number aviation fuels. A description of the process as used at the Abadan refinery of the Anglo-Persian Oil Co. is given by Moy (124). The ordinary Edeleanu process, since it operates with Type 1 phase diagrams, cannot produce a concentra-... 

Defize, J. C. L. On the Edeleanu Process for the Selective Extraction of Mineral Oils (in English), D. B. Centenos Uitgevers-Maatschappij, N. V., Amsterdam, 1938. 

Sulphur dioxide will normally oxidize metals at elevated temperatures, simultaneously forming metal sulphides and oxides. Liquid sulphm- dioxide is a relatively efficient solvent with some water-like properties. Polar inorganic compounds are usually insoluble or only sparingly soluble in liquid sulphur dioxide, whereas covalent inorganic and organic compoimds are often dissolved, mostly forming stable solutions. The fact that aromatic hydrocarbons will dissolve more readily than aliphatics in sulphur dioxide is exploited on an industrial scale for the extraction of aromatics from crude oil according to the Edeleanu process. 

Today, phenol, furfural, and cresylic acid are widely used as solvents. In the past, some refiners installed the Edeleanu process, in which the solvent is liquid sulfur dioxide, but the hazards of potential leaks made it imdesirable. Chlorinated ethers and nitrobenzene also have been used. 

On the industrial scene, the most prominent applications both in scale and number are seen in the petroleum industry. Liquid extraction is used here to separate petroleum fractions selectively and to purify or otherwise refine them. In the Edeleanu process, which is close to a century old, liquid sulfur dioxide is used to extract aromatics from various feedstocks. The removal of the ever-present sulfur compounds is accomplished by extraction with sodium hydroxide solutions. In addition, a wide range of organic solvents is used in the purification and refining of various lubricants. 

An example of this type of process of selective solute partitioning is urea based adductive crystallization. A saturated solution of urea in water at 70 °C may be mixed with a mixture of aromatic and paraffinic hydrocarbons present in a solvent at 40 °C (the Edeleanu process). Under conditions of appropriate refrigeration, lumps of urea-n-paraffin adducts appear as crystals (Findlay, 1962 Fuller, 1972). As shown in Figure 4.1.23(a), the host compound, urea, has crystallized into a form having a central tunnel open at both ends the tunnel accommodates the "guest paraffinic hydrocarbon molecule and holds it by van der Waals forces with m urea molecules forming the tunnel ... 

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