Page:Popular Science Monthly Volume 89.djvu/402

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388

��Popular Science Motithly

��separate each group into the final market form of the many products contained.

The secondary purpose of refining is to remove the impurities, color-bearing, and unstable or unsaturated compounds and free carbon. It may be well to point out at this time that in the first group distillation there is no sharp line of demarcation between gasoline and illu- minating oil or between any other similar fractions. Heavy constituents are mechanically carried over with the light portions and more volatile products are mix- ed with the heavy parts. In order to completely separate these, further distillation is necessary.

The crude naphtha dis- tillate is pumped from the running tank to an agita- tor where it is treated with sulphuric acid, washed with water to remove the free acid and neutralized with caustic soda, again washed and separated from the water. The treated naphtha is next sent to a steam still where it is divided by distillation into various market grades of gasoline and pumped from there to the finished naphtha storage tanks. (Fig. 2.)

The illuminating oil distillate is pumped to a steam still where the crude naphtha contained is sep- arated by distillation and sent to the crude naphtha still. The illuminating oil remaining is sent lo an agitator where it is acid treated, washed, neutralized, rewashed and filtered through Fuller's earth (Fig. 3) and pumped to the finished kerosene lamp oil storage tanks.

The crude light lubricating distillate passes from the running tank to a steam and fire still, for the purpose of changing (by heat) the character of the paraliin wax from the amorphous condition to wax that may be crystallized and for si'parating the fuel oil content. The lubricating distillate then goes to a chilling tank where its temperature is

��OPENING Fon DlSCHaOCiNfi

���Fig. 3. FuUer's Earth Filter

��lowered to such a degree as to cause crystallization of the wax. In this chilled condition it is then pumped to a wax filter press, under high pressure, where it is separated into crude scale wax and pressed lubricating distillate. The pressed distillate then goes to a steam and fire still, where the gas oil is separated from it. The remaining distillate is then divided into lubricating oils of different viscosity, varying from very light to me- dium light, by fractional distillation.

The oils of diflferent viscosities resulting from this fractional distillation are next sent to a Fuller's earth filter for the removal of color-bearing com- pounds and free carbon. From the filter, these oils are pumped to the finished lubricating oil storage tanks.

The crude scale wax is sent from the wax filter press to a sweater, where it is separated into scale wax and oil. The scale wax then goes to a Fuller's earth filter, through which it passes to the finished paraffin wax tanks.

The crude hea\-y lubri- cating distillate follows the same course in pro- cessing as that indicated for the light distillate. Fuel oil and paraffin wax are separated in the same manner. The fractional tlistillation of the remain- ing oil results in lubricatingoilsof heavier body than those recovered b\' the process- ing of the light lubricating distillate.

Crude cylinder stock is greatly thimied with naphtha, and then sent to a chilling lank where the paraffin wax, from which \aseline is made, settles out. The oil- naphtha portion is pumped to a I'uller's earth filter for the removal of color-bear- ing compounds and free carbon. From the filter it passes on to a steam still wluTc it is separated into naphtha and low cold test cylinder slock, l-'rom the still the oil is sent to a tank where it is blown with air to remove traces of mois- lurcmd llun to ihefinisiifd storage tanks.

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