Front velocity in the combustion of blends of poultry litter with straw

The paper presents experimental studies on the burning characteristics of poultry litter and its blends with straw in the context of their potential usage in small-scale heat and power generation. For comparison purposes classic fuel such as wooden pellets was also investigated. The samples were analyzed in terms of water content, chemical composition and devolatilization, heating values, ash composition and ignition temperatures. An experimental analysis was performed of the combustion process of various sample beds in a small laboratory reactor that covered the temperature measurements and visual observations. This resulted in estimation of the speeds of ignition front propagation in the studied fixed beds, which is of general importance in the design of grate-fired furnaces. The combustion dynamics was discussed in terms of the physical properties of the bed, such as bulk density and porosity. The authors concluded that the main issue regarding the efficiency of poultry litter combustion was closely connected to a low bulk density of the fuel bed, which led to faster combustion front propagation but lower temperatures compared to a more dense fuel bed such as a wood pellet bed.