FLY ASH BENEFICIATION

From 1997 CAER conference in Lexington, KY USA:

 

· School of Mechanical Engineering at Pusan National University. Pusan, Korea. Jae-Keun Lee and Seong-Chan Kim, et.al.

A dry two-stage process to remove unwanted and unburned carbon in fly ash:

Uses triboelectrostatic separation process to remove unburned carbon. Fly ash > 125 micro-meters contained most of the unburned carbon (33% LOI). Fly ash < 125 micro-meters was 4-5% LOI. Raw fly ash of 6-9.5% LOI is centrifugally classified to remove the fraction > 125 microns; then triboelectrostatic classification brings LOI down to <3% LOI. Recovery of 80% is reported.

 

· ReUse Technology. Kennesaw, GA. Blackstock,Tom and Fisher, Bryan.

Describes a process for removing ammonia from fly ash. Available NOx reduction technologies may contaminate the fly ash with various ammonia compounds or leave unburned carbon in ash.

 

· ASH PRO Liberation Process- Captures fly ash with filter receiver and transfers ash to hot air aeration chamber.

Separation Technologies, Inc. Needham, MA. Bittner, James and Gasiorowski, Stephan.

An electrostatic dry separation system to separate unburned carbon from ash at Brayton Point Power Plant of New England Power Co. Particles are triboelectrically charged by inter-particle contact. Carbon particles retain an opposite charge to the fly ash particles. The STI plant under one silo processes 20 tons/hr. and operates 24/7. LOI goes from 8.23% to 1.10%. Combined capacity of two separators =300,000 tons/yr.

From 1999 CAER conference in Lexington, KY USA:

· Separation Technologies, Inc. Needham, MA. Bittner, James and Gasiorowski, Stephan.

5 years of commercial fly ash beneficiation: The 5 separators triboelectrically separate unburned carbon from the fly ash at: US Generating Co.-Brayton Point (2 separators), Carolina Power and Light-RoxboroStation (2 separators), and Baltimore Gas and Electric-Brandon Shores Station. A new installation planned at Jacksonville’s Electric’s St. Johns River Power Plant.

Feed ash at 4.5-30% LOI is beneficiated to 2% LOI.

 

· The SEFA Group (www.sefagroup.com/)

Carbon Burnout (CBO) Technology is used on raw fly ash to reduce its carbon. Several ashes are blended in raw fed silo. A two- foot thick layer of ash covers the bottom of combustor where ash is burned. The flu gas is used to pneumatically convey the product ash through shell and tube heat exchanger where ash is cooled from 1300-300F. See the Wateree Plant in Wateree, SC and the Winyah plant in Georgetown, SC.

 

● Ash grinding and classification to produce superfine fly ash.