Dense Slurry Ash Management: Ash/Water Mixes to Maximize Economics and Environmental Performance

摘要

The Effluent Limitations Guidelines (ELG) and the Coal Combustion Residuals (CCR) rules are finalized. Coal plants are making major changes to comply. Dense slurry technology is an economical alternative to more traditional ash and wastewater management techniques. The technology combines ash and wastewater to stabilize both wastes and complies with the CCR and ELG rules by eliminating liquefaction risks, reducing dust, eliminating discharge of ash transport water, reducing or eliminating leachate and by improving leach performance of cured products. The chemistry of plant effluents varies regardless of similarities in the fuel burned. Variations in fuel, boiler type, combustion temperature, emission controls and other factors all affect ash and wastewater properties. Testing of a variety of ash and wastewater mixes helps quantify scale-up engineering, costs and optimization of long term environmental performance. Data and case studies of dense slurry system (DSS) laboratory studies, pilot tests and commercial installations are presented which describe the tests performed, the results of the tests and the effect of additives on the environmental performance of the cured products.