Solvent dewaxing process

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. 

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. 

MEK dewaxing a continuous solvent dewaxing process in which the solvent is generally a mixture of methyl ethyl ketone and toluene. 

Figure 5.28 Simplified flow schemes of (a) a conventional and (b) Mobil Oil s membrane solvent dewaxing processes. Refrigeration economizers are not shown. The first 3 million gallon/day commercial unit was installed at Mobil s Beaumont refinery in 1998. Polyimide membranes in spiral-wound modules were used [41-43]...

Another process that is used for treating is the solvent dewaxing process (Fig. 13.15) that accepts lubricating oil and, on occasion, deasphalted oil as the feedstock. 

In solvent dewaxing, the oil is diluted with a solvent that has a high affinity for oil, chilled to precipitate the wax, filtered to remove the wax, stripped of solvent, and dried. The solvents (principally propane, naphtha, methyl ethyl ketone-MEK) act as diluents for the high molecular weight oil fractions to reduce the viscosity of the mixture and provide sufficient liquid volume to permit pumping and filtering. Wax produced by the solvent dewaxing process is used to make (1) paraffins for candle wax, (2) microwax for cosmetics, and (3) wax for petroleum jelly. 

The octane boosting processes allow us to reduce cost by increasing yield without sacrificing product quality. To reduce cost, a new catalytic dewaxing process replaces an expensive noncatalytic process. Catalytic dewaxing does not have the temperature limitation of a solvent dewaxing process. Thus, it creates a new class of super-low freeze point or pour point products for low temperature applications. The... 

The solvent dewaxing process involves addition of solvent during the chilling of the waxy feed. The chilling process induces crystallization of the wax and the solvent is added to maintain the fluidity. The wax crystals are filtered by rotating drum filters, resulting in a lube oil filtrate and a slack wax with entrained solvent and oil. In both fractions, the solvent is recovered by successive vaporization and distillation. 

Figure S Simplied flow diagramm of ExxonMobil s solvent dewaxing process employing reverse osmosis. (Adapted from [16], with permission).

I 7 Membrane Technology in the Chemical Industry Future Directions (a) Conventional solvent dewaxing process... 

Hexyldecyl benzoate Jsopropyl palmitate SD alcohol 23-A solvent, dermatologicals Propylene glycol dioctanoate solvent, desulfurization Diisopropanolamine solvent, detergents Ethylene glycol diethyl ether solvent, dewaxing process Ethylene dichloride solvent, dichloramine-T Paraffin, chlorinated... 

Although the wax distillate and the cylinder stocks from vacuum units are usually dewaxed without difficulty, some refiners have found that an intermediate heavy wax distilliEite ciit must be produced to the amount of 3 to 6 per cent if the wax distillate and the cylinder stock are to have good dewaxing characteristics. The use of solvent dewaxing processes has eliminated most of these difficulties. 

Low-temperature Services. With the advent of solvent dewaxing processes and ethylene manufacture, the lack of impact or shock resistance of metals became an important consideration. Three general types of... 

The use of two dewaxing methods, i.e., pressing and centrifuging, has been a source of great expense to refiners. Almost all new plants employ solvents (Table 11-1). The Weir filter-aid process (patented in 1924) was the first commercial solvent dewaxing process. It involved the filtration of chilled naphtha oil solution mixed with about 15 per cent of filter aid (fuller s or diatomaceous earth). Modem solvent processes employ special solvents, such as acetone-benzene, trichlorethylene, ethylene dichloride-benzol (Barisol), smd particularly propane and methyl ethyl ketone-benzol. ... 

Wax Finishing. Slack wax from solvent dewaxing processes contains only about 8 per cent oil. Upon sweating, a scale wax containing less than 1 per cent oil is obtained. 

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