Fly ash utilization in the Western United States

摘要

More than 55% of the energy consumed in the United States is generated from coal combustion. This process creates coal combustion products (CCPs) in the form of fly ash, bottom ash, boiler slag, and flue gas desulphurization products. In 1998, 97.8 Mt of CCPs were generated by United States electrical utilities. Only 29% of this total was used for other applications, with the remaining 69.4 Mt landfilled. Fly ash is the major constituent of the total CCPs produced (57Mt) and 33.5% of this total was used primarily in cement and concrete, waste stabilization, structural fill, road base and mining applications. In the Western United States, 10.8 Mt of CCPs were produced (1998) and 19% utilized. The Western Regionleads in coal production in the United States and Wyoming is the principal coal-producing state. Most states in this area rely heavily (85%) on coal for electrical generation. Both Class C (high calcium) and Class F (high silica) fly ash are produced in this region. A survey of 38 power plants in this region found 44% utilization of fly ash. Distance to market and transportation influence the use of fly ash in the West. However, quality and class of fly ash can be the deciding factor as to whether a fly ash has a large market and is shipped greater distances. The significance of quality gives fly ash some characteristics of a speciality mineral.