Decoupling combustion characteristics of biomass pellets and their mixture with bituminous briquettes

Abstract

Co-firing coal and biomass has been thought to be a promising way to achieve the efficient and clean combustion of them, but few researches were concentrated on the application of the co-firing technology in the residential field. In this study, the decoupling co-combustion characteristics of bituminous briquettes (BB) and biomass pellets (BP) were first evaluated by thermalgravimetric mass spectrometer (TG/MS) measurements, followed by the experiments on the pollutant emissions of burning blending fuels in a typical household decoupling stove as well as the thermodynamic equilibrium calculation and X-ray powder diffractometer (XRD) analysis of their slagging/fouling characteristics. The synergistic effect of co-firing coal and biomass is clarified. The addition of BP improves the combustion performance of blending fuels, while bituminous briquettes enhance the combustion stability of blending fuels. In the decoupling combustion stove, the stable coal char layer together with biomass pyrolysis gases plays an important role in the suppression of NOx, which also promotes the burnout of combustibles and thus favors the reduction of CO emission. Possible ash-related issues of ultrafine/fine particle emissions and severe slagging/fouling tendency caused by burning BP alone can be effectively alleviated by the capturing and regulating effect of BB. Co-firing bituminous briquettes and biomass pellets directly in the decoupling furnace can be anticipated to find wide use in the residential field.