SF-86-14-1 -- Introducing Coal-Water Mix Fuels PDF

General considerations associated with the formulation and use of coal-water fuels (CWF) in heating applications are discussed in this overview. Selection of coal for CWF involves consideration of coal volatiles, heating value, ash composition and content, and equilibrium moisture.

Additives that can be used to modify the fuel mix properties include dispersants, pH modifiers, stabilizers, and biocides. The flow properties of the formulations produced are non-Newtonian (both time-dependent viscosity (thixotropic) and shear rate dependent viscosity). Pressure drops in piping systems are, however, still predictable and some discussion of techniques and results is included.

The carrier water in CWF leads to reduced boiler efficiency, lowered flame temperatures, and increased boiler flue gas flow. The magnitude of these effects is quantified as a function of fuel water content. Approaches toward achieving flame stability are also discussed .

BNLs combustion experience with boiler systems in the 1,000,000 Btu/h size class is reviewed . Studies have included moderately loaded slurries, highly loaded slurries, oil cofiring, and combustion air preheat.

Units: Dual