THE FUTURE
253
Thus, as geological processes increase their effect over time, the coal
precursors are transformed over time into the following:
1. Lignite, also referred to as brown coal, is the lowest
rank of coal and used almost exclusively as fuel for
steam-electric power generation.
2. Sub-bituminous coal: the properties range from those
of lignite to those of bituminous coal and are used primarily as fuel for steam-electric power generation.
3. 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
quantities also used for heat and power applications
in manufacturing and to make coke.
4. Anthracite: the highest rank; a harder, glossy, black
coal used primarily for residential and commercial
space heating.
The rank of a coal indicates the progressive changes in carbon,
volatile matter, and probably ash and sulfur that take place as coalification progresses from the lower-rank lignite through the higher
ranks of sub-bituminous, high-volatile bituminous, low-volatile
bituminous, and anthracite. The rank of a coal should not be confused with its grade. A high rank (e.g., anthracite) represents coal
from a deposit that has undergone the greatest degree of metamorphosis and contains very little mineral matter, ash, and moisture.
On the other hand, any rank of coal, when cleaned of impurities
through coal preparation will be of a higher grade.
The production of liquid fuels from coal is not new and has
received considerable attention because the concept does represent
alternate pathways to liquid fuels (Berthelot, 1869; Batchelder, 1962;
Anderson and Tillman, 1979; Whitehurst et al, 1980; Gorin, 1981;
Stranges, 1983; Stranges, 1987; Argonne, 1990; Speight, 2008). The
first major use of Fischer Tropsch technology was during the Second
World War, when Germany produced about 90% of the diesel and
aviation fuel. South Africa began liquefying coal in response to
apartheid-era sanctions, and in part as a result of its investment back
then, continues to derive about 30% of its fuel from liquefied coal.
In fact, the concept is often cited as a viable option for alleviating
projected shortages of liquid fuels as well as offering some measure
253
Thus, as geological processes increase their effect over time, the coal
precursors are transformed over time into the following:
1. Lignite, also referred to as brown coal, is the lowest
rank of coal and used almost exclusively as fuel for
steam-electric power generation.
2. Sub-bituminous coal: the properties range from those
of lignite to those of bituminous coal and are used primarily as fuel for steam-electric power generation.
3. 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
quantities also used for heat and power applications
in manufacturing and to make coke.
4. Anthracite: the highest rank; a harder, glossy, black
coal used primarily for residential and commercial
space heating.
The rank of a coal indicates the progressive changes in carbon,
volatile matter, and probably ash and sulfur that take place as coalification progresses from the lower-rank lignite through the higher
ranks of sub-bituminous, high-volatile bituminous, low-volatile
bituminous, and anthracite. The rank of a coal should not be confused with its grade. A high rank (e.g., anthracite) represents coal
from a deposit that has undergone the greatest degree of metamorphosis and contains very little mineral matter, ash, and moisture.
On the other hand, any rank of coal, when cleaned of impurities
through coal preparation will be of a higher grade.
The production of liquid fuels from coal is not new and has
received considerable attention because the concept does represent
alternate pathways to liquid fuels (Berthelot, 1869; Batchelder, 1962;
Anderson and Tillman, 1979; Whitehurst et al, 1980; Gorin, 1981;
Stranges, 1983; Stranges, 1987; Argonne, 1990; Speight, 2008). The
first major use of Fischer Tropsch technology was during the Second
World War, when Germany produced about 90% of the diesel and
aviation fuel. South Africa began liquefying coal in response to
apartheid-era sanctions, and in part as a result of its investment back
then, continues to derive about 30% of its fuel from liquefied coal.
In fact, the concept is often cited as a viable option for alleviating
projected shortages of liquid fuels as well as offering some measure