Power Generation - Hydrogen and Fuel Cells: Advances in Transportation and Power - page 190

Coal is the most abundant fossil fuel in the U.S. and many other coun-
tries. In the U.S. coal makes up about 95% of all fossil energy reserves. These
reserves could last several hundred years at the current level of coal con-
sumption. Major developing countries such as China and India, which are
now using more and more of the world's oil, also have large coal reserves.
Coal is also a source of hydrogen. The coal is gasified and the impu-
rities are removed so the hydrogen can be recovered. This results in sig-
nificant emissions of CO 2 .
GASIFICATION TECHNOLOGIES
The Tampa Electric Company plant in Polk County, Florida uses coal
gasification to generate some of the nation's cleanest electricity. Coal gas-
ification represents the next generation of coal-based energy production.
The first pioneering coal gasification power plants are now operating in
the United States and other nations. Coal gasification is gaining increasing
acceptance as a way to generate extremely clean electricity and other high-
value energy products.
Instead of burning coal directly, coal gasification reacts coal with
steam and carefully controlled amounts of air or oxygen under high tem-
peratures and pressures.
The heat and pressure breaks the chemical bonds in coal's complex
molecular structure with the steam and oxygen forming a gaseous mix-
ture of hydrogen and carbon monoxide. Gasification may be one of the
better ways to produce hydrogen.
Pollutants and greenhouse gases can be separated from the gaseous
stream. As much as 99% of sulfur and other pollutants can be removed
and processed into commercial products such as chemicals and fertilizers.
Unreacted solids can be collected and marketed as co-products such as
slag for road building.
The primary product is fuel-grade, coal-derived gas which is similar
to natural gas. The basic gasification process can also be applied to other
carbon-based feedstocks such as biomass or municipal waste.
Coal gasification offers a more efficient way to generate electric
power than conventional coal-burning power plants. In a conventional
plant, heat from the coal furnaces is used to boil water, creating steam for
a steam-turbine generator.
In a gasification-based power plant, the hot, high pressure coal gases