Page 20 - Synthetic Fuels Handbook

8 CHAPTER ONE

Currently, the only commercial production of bitumen from tar sand deposits occurs in
northeastern Alberta (Canada) where mining operations are currently used to recover the tar
sand. After mining, the tar sands are transported to an extraction plant, where a hot-water
process separates the bitumen from sand, water, and minerals. The separation takes place
in separation cells. Hot water is added to the sand, and the resulting slurry is piped to the
extraction plant where it is agitated. The combination of hot water and agitation releases
bitumen from the oil sand and causes tiny air bubbles to attach to the bitumen droplets,
which float to the top of the separation vessel, where the bitumen can be skimmed off.
Further processing removes residual water and solids. The bitumen is then transported and
converted to synthetic crude oil by thermal processes. Approximately 2 tons of tar sands
are required to produce 1 bbl of oil.
Both mining and processing of tar sands involve a variety of environmental impacts,
such as global warming and greenhouse gas emissions, disturbance of mined land and
impacts on wildlife and air and water quality. The development of a commercial tar sands
industry in the United States would also have significant social and economic impacts on
local communities. Of special concern in the relatively arid western United States is the
large amount of water required for tar sands processing. Currently, tar sands extraction and
processing require several barrels of water for each barrel of oil produced, though some of
the water can be recycled.
To some observers, this proves the viability of the entire process while to others the
energy requirements for the production of the synthetic crude oil make it marginally
feasible for a significant percentage of world oil production to be extracted from tar
sand.
Nevertheless synthetic crude oil is produced that has given Canada a measure of self
sufficiency (at a cost) that is currently moving toward 1,500,000 bbl of synthetic crude
oil per day.

1.2.2 Coal

Coal is a fossil fuel formed as an organic sediment (Fig. 1.2) in swamp ecosystems where
plant remains were saved by water and mud from oxidization and biodegradation. Coal is
a combustible black or brownish-black organic rock and is composed primarily of carbon
along with assorted other elements, including sulfur. It is extracted from the ground by coal
mining, either underground mining or open-pit mining (surface mining).
As geologic processes apply pressure to peat over time, it is transformed successively
into: (a) lignite—also referred to as brown coal and is the lowest rank of coal and used
almost exclusively as fuel for steam-electric power generation; (b) sub-bituminous coal—
whose properties range from those of lignite to those of bituminous coal and are used
primarily as fuel for steam-electric power generation; (c) bituminous coal—a dense coal,
usually black, sometimes dark brown, often with well-defined bands of bright and dull
material, used primarily as fuel in steam-electric power generation, with substantial quan-
tities also used for heat and power applications in manufacturing and to make coke; and
(d) anthracite—the highest rank; a harder, glossy, black coal used primarily for residential
and commercial space heating.
The crude oil price has been sharply rising in the twenty-first century and there are
indications that the high crude oil price is here to stay, rather than a temporary phe-
nomenon. Even after considering the changes in various economic factors involving
energy industries, production of transportation fuels or fuel oils via coal liquefaction is
certainly an outstanding option for the sustainable future. Further, the products
of coal liquefaction can be refined and formulated to possess the properties of