Dewaxing process

Although lubricant base stocks have been subjected to dewaxing processes, they still contain large amounts of paraffins that result in a high pour point for the oil. In the paragraph on the cold behavior of diesel fuels, additives were mentioned that modify the paraffin crystalline system and oppose the precipitation of solids. 

Dewaxing, catalytic Dewaxing process Dewaxing processes Dexamethasone... 

Solvent Treatment. Solvent processes can be divided into two main categories, solvent extraction and solvent dewaxing. The solvent used in the extraction processes include propane and cresyHc acid, 2,2 -dichlorodiethyl ether, phenol (qv), furfural, sulfur dioxide, benzene, and nitrobenzene. In the dewaxing process (28), the principal solvents are benzene, methyl ethyl ketone, methyl isobutyl ketone, propane, petroleum naphtha, ethylene dichloride, methylene chloride, sulfur dioxide, and iV-methylpyrroHdinone. 

Insofar as they are used to purify other products, several processes used in the refinery fall under the classification of dewaxing processes however, such processes must also be classified as wax production processes (2). Most commercial dewaxing processes utilize solvent dilution, chilling to crystallize the wax, and filtration (28). The MEK process (methyl ethyl ketone—toluene solvent) is widely used. Wax crystals are formed by chilling through the walls of scraped surface chillers, and wax is separated from the resultant wax—oil—solvent slurry by using fliUy enclosed rotary vacuum filters. 

On the other hand, intermediate paraffin distillates contain paraffin waxes and waxes intermediate in properties between paraffin and microwaxes. Thus, the solvent dewaxing process produces three different slack waxes depending on whether light, intermediate, or heavy paraffin distillate is processed. The slack wax from heavy paraffin distillate may be sold as dark raw wax, the wax from intermediate paraffin distillate as pale raw wax. The latter is treated with lye and clay to remove odor and improve color. 

Bari-Sol A petroleum dewaxing process using solvent extraction by a mixture of dichloroethane and benzene. 

Iso-CDW [Isomerization and catalytic dewaxing] A general term for dewaxing processes which include these two processes. Exemplified by Isodewaxing, MSDW. 

Isodewaxing A catalytic dewaxing process developed by Chevron Research Technology. It incorporates catalysts that achieve both wax isomerization and shape-selective cracking. 

MSDW [Mobil selective dewaxing] A catalytic dewaxing process which uses a catalyst containing a shape-selective molecular sieve and a noble metal. 

Genis, 0. (1997) UOP catalytic dewaxing process, in Handbook of Petroleum Refining Processes, 2nd edn (ed. R.A. Myers), McGraw-Hill, pp. 8.49-8.53... 

The problem received concentrated attention. One method (87) introduced used naphtha as a diluent, with an inert material, such as diatomaceous earth, to build up the wax crystal structure artificially, so that relatively good filtration rates were obtained and a wash could be applied to the wax cake on the filter to displace the retained oil.. This method was identified as the Weir process or filter-aid dewaxing process and was placed in commercial operation about 1928 (30). It was the first commercial process capable of successfully dewaxing the intermediate distillates, as well as paraffin distillates of lowest viscosity and residual stocks of highest viscosity. 

In operation of the filter-aid dewaxing process, the waxy stock is diluted with naph-... 

The first commercial installation employing special organic solvents in dewaxing was made by the Indian Refining Co. in 1927 (32). The process as originally used employed a mixture of acetone and benzene as the special solvents, based on the inventions of F. X. Govers. The process as further developed employs a mixture of methyl ethyl ketone and aromatic solvents such as benzene and toluene. It is known as the solvent dewaxing process. 

This process is the most widely used dewaxing process in the petroleum industry today. Sixty-one units have been installed throughout the world. 

This dewaxing process is always installed in combination with Edeleanu solvent extraction because recovery of the solvents from the preceding step is not required. For example, if dewaxing follows the refining operation, the raffinate solution is taken directly from the extraction unit and the solvent composition is adjusted to that used for dewaxing by the addition of a benzene-rich solvent which is readily recovered from the dewaxed oil solution because of the wide difference in boiling points of the solvents. 

Twenty-five years ago the dewaxing processes available to the refiner of lubricating oils were the cold pressing method applicable only to low viscosity distillates and the cold settling and centrifuge methods applicable to certain residual oils. A vast amount of... 

Dewaxing process - [PETROLEUM - REFINERY PROCESSES, SURVEY] (Vol 18)... 

Acetone-benzol process a dewaxing process in which acetone and benzol (benzene or aromatic naphtha) are used as solvents. 

Bari-Sol process a dewaxing process that employs a mixture of ethylene dichloride and benzol as the solvent. 

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