The Grate-Firing Boilers Grate Movement Impact onto NOx, SO2 Emissions

Abstract

Measurements of pollutant concentrations in the flue gases of a biofuel boiler show that pollutants concentrations fluctuate by 10-100% and more at short time intervals. Large fluctuations in concentrations hinder the effective application of pollution reduction measures. During the research, flue gas composition measurements were performed in 4 MW, 8 MW industrial biofuel boilers and 20 kW experimental model. The results of the research showed that the change of CO, NO, NO₂, SO₂, H₂S, O₂ and particulate matter concentrations is related to the periodicity of the boiler grate movement. During the movement of the grate, the surface of the fuel bed is mechanically disrupted. The different composition of the fuel layers is mixed and this affects the changes in the concentration of combustion products. The clarity of the concentration fluctuations depends on the emissions, the type of fuel and the combustion parameters.