Page 26 - Synthetic Fuels Handbook

14 CHAPTER ONE

Corporation. Following the sale of the Elk Hills by the U.S. Department of Energy, two
of the Naval Oil Shale Reserves, both in Colorado are being transferred to Department of
Interior’s Bureau of Land Management, thereby offering commercial mining leasing for
gas and petroleum production. Considering the environmental success of Elk Hills field
project, it is foreseeable that many of the oil shale fields in the world can be more seriously
explored for commercial exploitation for petroleum (shale oil crude) and gas (natural gas
and LPG) generation.
Environmental technology has also been constantly enhanced for better management of
underground waterways and surface water treatment, thus alleviating the burden of envi-
ronmental constraints from oil shale industries. The most significant merits of shale oil are
in its relative ease of producing high-quality liquid fuel via relatively simple processing of
oil shale rock. High-quality liquid fuels, especially from alternative sources, are going to be
more and more strongly demanded due to their minimal impact on lifestyle changes. Other
factors, that may have significant effects on boosting the interest in oil shale commercial-
ization, may include the ever-increasing petroleum market price, the fluctuating supply of
petroleum resources, the steeply rising cost of natural gas, the nondwindling appetite of
petroleum-like liquid fuels, and the public fear of petroleum depletion.
It may not be a long stretch in prediction for the world energy market in the future that
oil shale will be a very valuable commodity as an alternative source for clean liquid fuel
and the resource is not easily depletable. Transportation of oil shale will then become a
very important issue, since the fuel cost structure is more likely to justify the long distance
transportation of oil shale. However, until that time, oil shale will always remain as a
contingency plan, as an invaluable alternative source for petroleum-like liquid fuel. There
is always the advantage and temptation of using oil shale since it minimizes the lifestyle
change in energy consumption pattern even without relying on the petroleum resource.

1.2.4 Natural Gas
Natural gas is a gaseous fossil fuel consisting primarily of methane but including significant
quantities of ethane, butane, propane, carbon dioxide, nitrogen, helium, and hydrogen sulfide.
It is found in natural gas fields (unassociated natural gas, non-associated natural gas), oil
fields (associated natural gas) and in coal seams or beds (hence coalbed methane).
Natural gas is often informally referred as simply gas and before it can be used as a fuel,
it must undergo extensive processing (refining) to remove almost all materials other than methane.
The by-products of that processing include ethane, propane, butanes, pentanes and higher
molecular weight hydrocarbons, elemental sulfur, and sometimes helium and nitrogen.
Natural gas is colorless in its pure form and is a combustible mixture of hydrocarbon
gases and while the major constituents is methane, ethane, propane, butane and pentane are
also present but the composition of natural gas varies widely.
Natural gas can also be used to produce alternative liquid fuels and the process is often
referred to as gas-to-liquid (GTL) (Table 1.4). The term alternative fuel includes methanol,
ethanol, and other alcohols, mixtures containing methanol, and other alcohols with gasoline
or other fuels, biodiesel, fuels (other than alcohol) derived from biologic materials, and any
other fuel that is substantially not a petroleum product.
The production of liquid fuels from sources other than petroleum broadly covers liq-
uid fuels that are produced from tar sand (oil sand) bitumen, coal, oil shale, and natural
gas. Synthetic liquid fuels have characteristics approaching those of liquid fuels generated
from petroleum but differ because the constituents of synthetic liquid fuels do not occur
naturally in the source material used for the production. Thus, the creation of liquids to be
used as fuels from sources other than natural crude petroleum broadly defines synthetic
liquid fuels. For much of the twentieth century, the synthetic fuels emphasis was on liquid