5 10 15 20


Figure 2.13. Steam stripping of petroleum fractions in four actual trays (with permission of Oil and Gas Journal).

ASTM boiling range which, as was pointed out earlier, is a loose specification for composition of matter. The following general classes of distillate products are obtained from petroleum.

Liquefied Petroleum Gas (LPG)—ethane, propane, butanes (mixed and separated) and isopentane. These products cannot be produced directly from crude distillation and require further high pressure distillation.

Naphtha (Gasoline)-pentane through 400 degrees F ASTM end point. There are many grades and boiling ranges of naphthas, the properties of which are influenced by their planned end use. Many refineries produce a 400 degree F end point naphtha as an overhead distillate from the atmospheric tower and then fractionate it as required in separate facilities. If the product pattern can be defined well enough it is more economical to produce a light naphtha as the overhead distillate and a heavy naphtha as the lightest side-

stream froim the crude tower. Most naphthas are used in motor gasoline, either directly or as catalytic reformate. There is some demand for naphtha boiling range liquids as petrochemical feedstocks, principally for thermal cracking to olefins otr for reforming and extraction of aromatics.

Light Distillate—ASTM end points in the range of 525 to 575 degrees F. A full range light distillate is kerosene having an ASTM boiling range of 325 to 550 degrees F. An important distillate is JP-4 jet fuel which has an ASTM boiling range of approximately 150 to 475 degrees F. This product is'^blended from suitable stocks of naphtha and light distillate. However, under proper operating conditions, this material could be yielded directly from the atmospheric tower aS a light distillate, ri

Heavy pistillate—ASTM end points in the range of 650 to 700 degrees F. Diesel fuel is a blend of light distillate and

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