Carbon monoxide and nitric oxide concentrations in the flue gas during the combustion of agricultural biomass briquettes in a 25 kW log gasification boiler

A study was made of the two-stage combustion of agricultural biomass briquettes (rye straw, miscanthus, hay, corn stover) in a 25 kW wood log gasification boiler. The following correlations for selected fuel loads and biomass types were shown: fluctuation of temperature over time both in the gasification chamber and in the combustion zone, variation over time of carbon monoxide and nitric oxide concentrations, correlation between nitric oxide and carbon monoxide concentrations in the flue gas, and variation of carbon monoxide and nitric oxide concentrations versus oxygen concentration and temperature in the combustion zone. Two-stage combustion of agricultural biomass proved to be efficient, as slag was not generated. Relatively high carbon monoxide concentrations in the flue gas resulted from the lack of automated regulation of air supply to the gasification chamber and the combustion zone.