Page 183 - Synthetic Fuels Handbook

CHAPTER 6

FUELS FROM OIL SHALE

Oil shale is an inorganic, nonporous sedimentary marlstone rock containing various
amounts of solid organic material (known as kerogen) that yields hydrocarbons, along with
non-hydrocarbons, and a variety of solid products, when subjected to pyrolysis (a treatment
that consists of heating the rock at high temperature).
Thus, by definition, kerogen is naturally occurring insoluble organic matter found in
shale deposits. However, shale oil is the synthetic fuel produced by the thermal decomposi-
tion of kerogen at high temperature [>500°C (>932°F)]. Shale oil is referred to as synthetic
crude oil after hydrotreating.
The oil shale deposits in the western United States contain approximately 15 percent
organic material by weight. By heating oil shale to high temperatures, kerogen can be
released and converted to a liquid that, once upgraded, can be refined into a variety of
liquid fuels, gases, and high-value chemical and mineral by-products. The United States
has vast known oil shale resources that could translate into as much as 2.2 trillion bar-
rels of known kerogen oil-in-place. Oil shale deposits concentrated in the Green River
Formation in the states of Colorado, Wyoming, and Utah account for nearly three-quarters
of this potential.
Because of the abundance and geographic concentration of the known resource, oil shale
has been recognized as a potentially valuable U.S. energy resource since as early as 1859,
the same year Colonel Drake completed his first oil well in Titusville, Pennsylvania (Chap. 1).
Early products derived from shale oil included kerosene and lamp oil, paraffin, fuel oil,
lubricating oil and grease, naphtha, illuminating gas, and ammonium sulfate fertilizer.
Since the beginning of the twentieth century, when the U.S. Navy converted its ships
from coal to fuel oil, and the nation’s economy was transformed by gasoline-fueled auto-
mobiles and diesel-fueled trucks and trains, concerns have been raised about assuring ade-
quate supplies of liquid fuels at affordable prices to meet the growing needs of the nation
and its consumers.
America’s abundant resources of oil shale were initially eyed as a major source for these
fuels. Numerous commercial entities sought to develop oil shale resources. The Mineral
Leasing Act of 1920 made petroleum and oil shale resources on federal lands available for
development under the terms of federal mineral leases. Soon, however, discoveries of more
economically producible and refinable liquid crude oil in commercial quantities caused
interest in oil shale to decline.
Interest resumed after World War II, when military fuel demand and domestic fuel
rationing and rising fuel prices made the economic and strategic importance of the oil
shale resource more apparent. After the war, the booming post–World War II economy
drove demand for fuels ever higher. Public and private research and development efforts
were commenced, including the 1946 U.S. Bureau of Mines Anvil Point, Colorado oil shale
demonstration project. Significant investments were made to define and develop the resource
and to develop commercially viable technologies and processes to mine, produce, retort, and
upgrade oil shale into viable refinery feedstocks and by-products. Once again, however,
major crude oil discoveries in the lower-48 United States, off-shore, and in Alaska, as well

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