The scheme of a refinery is simple. It consists of : (a) Crude oil storage tanks, to hold oil preparatory to refining.
(b) Stills in which to distil the oil.
(c) Condensers in which to cool the product as it comes off the stills.
(d) Agitators for the treatment of the condensed product to remove bad odors and impurities.
(e) Tanks in which to store the final products after treatment in the agitators or to hold the products left in the still.
(f) Filters to filter the oils.
(g) Wax presses and wax machine.
Once the character of the oil and knowledge obtained as to its best use has been determined, refining operations are commenced in earnest.
Refining Practice.—The refining of crude oil is divided into two stages: (A) The separation into groups or "cuts" by distillation.
(B) The separation and finishing of the groups or "cuts." The first stage is well illustrated in Figs. 87 and 88. The crude oil is run into the crude still and heated. The products are separated in the aerial condenser tower and then cooled in the water condenser box.
The products as they leave the condensers or coolers are conducted by carrying pipes to the re ceiving house (see Fig. 88).
in this house the pipes are exposed, and at points in each of them there are glass-covered "look" boxes, through which the operative can see the color of the liquid, by which the quality is gauged. Samples are also taken here. There is a system of mainfolds here so that the stream of liquid can be switched to any desired tank by the opening of one valve and the closing of another.
The resulting groups or fractions are: 1. Gasoline distillate.
2. Illuminating-oil dis tillate.
3. Gas-oil distillate.
4. Crude lubricating dis tillate.
5. Crude cylinder stock residuum.
Each of these groups con tains some of the product of the group above it. Illuminating-oil distillate contains some gasoline dis tillate. Gas-oil distillate contains some illuminating-oils distillate, and so on through each group. Further distillation called reducing is necessary. These products must not only be separated but all impurities must be removed.