Page 75 - Synthetic Fuels Handbook

CHAPTER 3

FUELS FROM PETROLEUM
AND HEAVY OIL

3.1 HISTORY

A petroleum refinery is a group of manufacturing plants (Fig. 3.1) which are used to sepa-
rate petroleum into fractions and the subsequent treating of these fractions to yield mar-
ketable products, particularly fuels (Kobe and McKetta, 1958; Nelson, 1958; Gruse and
Stevens, 1960; Bland and Davidson, 1967; Hobson and Pohl, 1973). The configuration of
refineries may vary from refinery to refinery. Some refineries may be more oriented toward
the production of gasoline (large reforming and/or catalytic cracking) whereas the configu-
ration of other refineries may be more oriented toward the production of middle distillates
such as jet fuel and gas oil.
In general, crude oil, once refined, yields three basic groupings of products that are
produced when it is broken down into cuts or fractions (Table 3.1). The gas and gasoline
cuts form the lower boiling products and are usually more valuable than the higher boiling
fractions and provide gas (liquefied petroleum gas), naphtha, aviation fuel, motor fuel, and
feedstocks, for the petrochemical industry. Naphtha, a precursor to gasoline and solvents,
is extracted from both the light and middle range of distillate cuts and is also used as a
feedstock for the petrochemical industry. The middle distillates refer to products from the
middle boiling range of petroleum and include kerosene, diesel fuel, distillate fuel oil, and
light gas oil. Waxy distillate and lower boiling lubricating oils are sometimes included in
the middle distillates. The remainder of the crude oil includes the higher boiling lubricating
oils, gas oil, and residuum (the nonvolatile fraction of the crude oil). The residuum can also
produce heavy lubricating oils and waxes but is more often used for asphalt production. The
complexity of petroleum is emphasized insofar as the actual proportions of light, medium,
and heavy fractions vary significantly from one crude oil to another.
The refining industry has been the subject of the four major forces that affect most
industries and which have hastened the development of new petroleum-refining processes:
(a) the demand for products such as gasoline, diesel, fuel oil, and jet fuel; (b) feedstock
supply, specifically the changing quality of crude oil and geopolitics between different
countries and the emergence of alternate feed supplies such as bitumen from tar sand,
natural gas, and coal; (c) environment regulations that include more stringent regulations
in relation to sulfur in gasoline and diesel; and (d) technology development such as new
catalysts and processes.
The general trend throughout refining has been to produce more products from each bar-
rel of petroleum and to process those products in different ways to meet the product speci-
fications for use in modern engines. Overall, the demand for gasoline has rapidly expanded
and demand has also developed for gas oils and fuels for domestic central heating, and fuel
oil for power generation, as well as for light distillates and other inputs, derived from crude
oil, for the petrochemical industries.

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