Performance of a Burner with Coal and Coal-Bio-Solid Fuel Blends

Abstract

Powerplants spend nearly 50 billion dollars a year on fuel cost, and coal accounts for over 55% of the fuel used in the utility industries. The fuel cost could be reduced by supplementing coal fuels with alternative renewable fuels such as the byproducts of industries located in the vicinity of the powerplants. One of the byproducts of feedlots is manure, a biosolid fuel that is cheaper than coal, on a tonnage and heat-value basis. Coal-manure or, more simply, blend technology is proposed as a beneficial use of manure for powerplants located near feedlots. Experiments were performed in a small-scale boiler burner facility with coal only, and then for 80:20 blends on a wet-weight (as-received basis). Data were taken during the warm up, gasification, and combustion. Three types of feedlot manure were examined for blending: raw feedlot, partially composted feedlot, and finished composted feedlot. A summary of the findings is as follows: 1) Manure contained up to 80% volatile matter (VM) on a dry ash-free basis, which was twice the VM of conventional coal. 2) Combustion efficiency was slightly higher with the coal-manure than with coal. 3) NO A emission increased from 420 ppm at 80% burned fraction (BF) to 550 ppm at 95% BF for coal, whereas corresponding numbers for the were 620-550 ppm. 4) SO* increased from 30 to 180 ppm for coal, whereas for the it was nearly 0 ppm up to 90 % BF, but increased to 10 ppm at 95% BF.