Three New Ash Beneficiation Processes for the 21st Century


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Title: Three New Ash Beneficiation Processes for the 21st Century

Author(s): Bruce W. Ramme, Bryan C. Fisher, and Tarun R. Naik

Publication: Special Publication

Volume: 199


Appears on pages(s): 325-342

Keywords: aggregate; carbon; cement

Date: 6/1/2001

Several new coal-fired combustion system modifications have been designed to improve the quality of air emissions from power plants. These plant modifications have led to changes in the character of fly ash, and presented challenges for many of it’s conventional uses. For example, low NOx burner systems improve air emissions but also have the side effect of increasing the carbon in the fly ash. Wisconsin Electric Power Company (WE) has developed three new coal ash beneficiation processes for carbon and/or ammonia removal. These new processes have been demonstrated at various Wisconsin Electric coal fired-power plants located in Michigan and Wisconsin. The processes take advantage of utilizing the residual energy in high carbon fly ash and bottom ash; while also producing high quality fly ash for use as a supplementary cementing material for the concrete industry. These beneficiation processes are also designed to remove any residual ammonia contained in the fly ash from advanced NOx reduction systems such as Selective Catalytic Reduction (SCR), Selective Non-Catalytic Reduction (SNCR), and Amine Enhanced Fuel Lean Gas Rebum (AEFLGR). These new ash beneficiation processes are designed both as stand alone systems or potential additions to existing power plants. In some cases it may be advantageous to rebum high carbon coal ash from one power plant by transporting it to another where more complete combustion normally occurs.