Low Solids Coal Water Slurry Cofiring for NOx Trim

Over the past decade, members of the Upgraded Coal Interest Group and EPRI, the Department of Energy, the Energy and Environmental Research Corporation (GE-EER), Washington Energy Processing (WEP), Penn State University and the previous owners and operators of Seward Station located in western Pennsylvania, conducted a series of formulation and combustion tests using coal waste fines as a low solids coal water slurry cofiring fuel for electric power generation. The fine coal was recovered from coal fines impoundments and fresh coal cleaning plant fines that were cleaned, thickened and then cofired with pulverized coal in utility scale boilers. This paper explains the need for a program to eliminate these impoundments and describes the results of some of the tests conducted on the technology that demonstrate the effectiveness of trimming NOx emissions by the use of slurry cofiring. This method of trimming NOx emission has been shown to have the capability of reducing NOx emissions by 20% to 35% below the levels achieved by some low NOx burners and selective non-catalytic reduction systems (SNCRs).