Improvement of particulate matter emission from biomass pellet fuel combustion by adding pulping effluent during preparation

Low particulate matter(PM) emissions are a research hotspot pursued in biomass fuel fields. Herein, pulping effluent, an industrial byproduct of the pulping industry, was employed to prepare biomass pellet fuel by combining with reed residue through biomass densification technology. The pyrolysis behavior of pellet fuel particle size and concentration of PM emissions, as well as the composition of solid residual after combustion were investigated to study the influence mechanism of pulping effluent on PM emissions. Results showed that the organic component in pulping effluent can act as adhesive to endow pellet fuel with high density, which effectively enhanced the mechanical properties of pellet fuel by 46 % and notably reduced the concentration and size of PM emission by hindering the discharge of alkaline metals. Meanwhile, the mineral in pulping effluent diminished the production of PM pollutants via limiting the conversion of alkaline metals to PM. The concentration of PM emissions of pellet fuel at 10 % pulping effluent addition was 0.15 mg/g, significantly lower than that of pellet fuel without pulping effluent(4.05 mg/g), representing a 96 % reduction. The beneficial effect of pulping effluent addition on the discharge of PM pollutants can provide a new approach to construct high-performance biomass-based pellet fuels. • Pulping effluent added cut PM emissions by reducing concentration and size. • Organics acted as binder, boosting mechanical strength and densification. • Minerals suppressed alkaline metal conversion into PM, curtailing emissions.