OIL PRICES
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of hydrocarbons, this first and basic refining process is aimed at
separating the crude oil into its fractions or broad boiling ranges of
the various component hydrocarbons. Crude oil is heated and put
into a still (distillation column) and different products boil off and
can be recovered at different temperatures. The lighter products,
including liquid petroleum gases (LPG), naphtha, and so-called
straight run gasoline (i.e. the gasoline fraction distilled directly
from the crude oil without further processing), are recovered at the
lowest temperatures. Middle distillates; such as jet fuel, kerosene,
home heating oil, and diesel fuel distill next. Finally, the highest
molecular weight fractions (residual fuel oil and residuum) are
recovered. Additional processing follows crude distillation and
involves the use of a variety of highly complex units designed for
very different upgrading processes to produce the most desirable
lower molecular weight products.
At this point, the lower boiling fractions from the distillation
tower are sent to treating units while the higher boiling fractions
are converted into streams (intermediate components) that eventually become finished products, such as gasoline.
The most widely used conversion method uses high temperature and pressure to convert (crack) higher molecular weight (highboiling) hydrocarbons into lower molecular weight (low-boiling)
products. Fluid catalytic cracking (cat cracking), is the basic gasoline-making process. Using heat of approximately 500°C, 932°F, low
pressure, and a catalyst (a substance that accelerates chemical reactions), the cat cracker can convert most relatively heavy fractions
into lower molecular weight gasoline constituents. Hydrocracking
applies the same principles but uses a different catalyst, slightly
lower temperatures of approximately 450°C, 842°F, much greater
pressure, and hydrogen to obtain conversion to the desired products.
Some refineries employ coking units, which use heat of approximately 500°C, 932°F to convert the distillation residuum into lowerboiling products and coke, which may be used as an industrial fuel.
Cracking and coking are not the only forms of conversion and
other refinery processes, instead of splitting molecules, rearrange
them to add value. Alkylation, for example, makes gasoline components by combining some of the gaseous byproducts of cracking. Reforming uses heat, moderate pressure and catalysts to turn
naphtha, a low-boiling, relatively low-value fraction, into highoctane gasoline components. To make gasoline, refineries carefully
combine a variety of streams from the processing units to produce
185
of hydrocarbons, this first and basic refining process is aimed at
separating the crude oil into its fractions or broad boiling ranges of
the various component hydrocarbons. Crude oil is heated and put
into a still (distillation column) and different products boil off and
can be recovered at different temperatures. The lighter products,
including liquid petroleum gases (LPG), naphtha, and so-called
straight run gasoline (i.e. the gasoline fraction distilled directly
from the crude oil without further processing), are recovered at the
lowest temperatures. Middle distillates; such as jet fuel, kerosene,
home heating oil, and diesel fuel distill next. Finally, the highest
molecular weight fractions (residual fuel oil and residuum) are
recovered. Additional processing follows crude distillation and
involves the use of a variety of highly complex units designed for
very different upgrading processes to produce the most desirable
lower molecular weight products.
At this point, the lower boiling fractions from the distillation
tower are sent to treating units while the higher boiling fractions
are converted into streams (intermediate components) that eventually become finished products, such as gasoline.
The most widely used conversion method uses high temperature and pressure to convert (crack) higher molecular weight (highboiling) hydrocarbons into lower molecular weight (low-boiling)
products. Fluid catalytic cracking (cat cracking), is the basic gasoline-making process. Using heat of approximately 500°C, 932°F, low
pressure, and a catalyst (a substance that accelerates chemical reactions), the cat cracker can convert most relatively heavy fractions
into lower molecular weight gasoline constituents. Hydrocracking
applies the same principles but uses a different catalyst, slightly
lower temperatures of approximately 450°C, 842°F, much greater
pressure, and hydrogen to obtain conversion to the desired products.
Some refineries employ coking units, which use heat of approximately 500°C, 932°F to convert the distillation residuum into lowerboiling products and coke, which may be used as an industrial fuel.
Cracking and coking are not the only forms of conversion and
other refinery processes, instead of splitting molecules, rearrange
them to add value. Alkylation, for example, makes gasoline components by combining some of the gaseous byproducts of cracking. Reforming uses heat, moderate pressure and catalysts to turn
naphtha, a low-boiling, relatively low-value fraction, into highoctane gasoline components. To make gasoline, refineries carefully
combine a variety of streams from the processing units to produce