Page 33 - New Trends In Coal Conversion

2 New Trends in Coal Conversion

prehistoric times, its properties as a fuel seem to have been known since some 1000
years ago. In fact, the use of coal as a fuel probably dates back from its first use in
China, 1000 years BC (Finkelman and Greb, 2008). The National Coal Council
(2015) reported that during the second and third centuries, AC coal was used in
Rome basically as an energy source (heating source). By the 18th century coal had
replaced wood charcoal mainly because coal burned cleaner and gave off more heat.
At that time coal also contributed to the industrial revolution. More recently, in
most industrialized countries, coal has been a key source of energy and a major
contributor to their economic growth.
Coal is the world’s cheapest, most abundant, and widely distributed fossil fuel, and
today it is still a primary energy source for electric power, accounting for 41% of en-
ergy generation in the world (National Coal Council, 2015). According to recent esti-
mates, and despite its slight decline in recent years, coal is expected to remain the
second largest energy source worldwide until 2030e40 (U.S. Energy Information
Administration, 2016, 2017).
In addition to electric power generation, the main uses of coal are for steel industry
as well as for the production of cement and chemicals. In the steel industry, coal is
used to produce coke which is used in blast furnaces for smelting iron ore to produce
molten iron, which is a primary component of steel. Seventy percent of the steel pro-
duced in the world is made using coal (National Coal Council, 2015). Coal is also used
in the manufacturing process of cement, ferroalloys, nonferrous metals such as
aluminum, lime, and bricks. Cement is produced in kilns that use coal as fuel to
heat the raw materials to produce the clinker, which is one of the components in
the manufacture of cement. Moreover, coal is an important feedstock in the production
of carbon materials such as coal-based activated carbon with a high surface area for air
and water treatments and chemical-derived products such as oils, tar, and pitches for a
wide range of chemical products such as fertilizers and primary chemicals among
others.
However, at the same time, coal is also an intensive source of pollutant emissions,
mainly carbon emissions which are directly related to the global warming and climate
change. Despite recent environmental policies in some developed countries against
the use of coal, the world continues to be heavily dependent on this fossil fuel.
The future of coal utilization in a sustainable development scenario will be condi-
tioned by the capacity of reducing associated emissions through the construction
of advanced coal power plants in case of power generation and to make industrial
processes using coal so efficient that they reduce pollutant emissions to the point
of near-zero emissions.
Because of the importance of coal in the economic development of many countries,
this natural resource has been thoroughly researched over the years, particularly during
the last century to the point where all its characteristics and properties that make it such
a versatile product are known. This chapter describes and summarizes the general
knowledge acquired about coal in relation to its formation, worldwide resources and
reserves, coal composition and properties, and all the characteristics relevant for
describing the quality of a coal when it is used in the main conversion processes: com-
bustion, gasification, and cokemaking.