Applying multicomponent dry water agent for explosion suppression of pulverized biomass fuels

The explosion hazards of pulverized biomass fuels have threatened the safe processing and utilization of biomass energy. To suppress the biomass explosions, monosodium phosphate (MSP) and gellan gum (GG) were introduced as additives to produce the multicomponent dry water (DW) agents in this study. The modified MSP-DW and MSP-GG-DW suppressants presented core-shell structures with better stability if compared to the binary DW particles. Their suppression effects on two typical biomass fuels categorized in St1 explosion hazard, e.g., corn stalk and pine sawdust, were investigated in a 20-L chamber. The results showed the biomass explosion parameters including maximum overpressure P_max, maximum rate of pressure rise (dP/dt)_max, and flame propagation speed V_f all gradually decreased with increasing the proportions of DW suppressants, wherein the MSP-DW performed the superior suppressing efficiency. Applying 50 % of modified MSP-DW and MSP-GG-DW was found promising to completely suppress both corn stalk and pine sawdust explosions. Thermogravimetric analysis indicated that DW suppressants slow down the biomass pyrolysis and inhibit the release of flammable volatiles. The decomposition of MSP brought additional chemical effects along with thermal quenching, leading to advantages in explosion suppression. The multicomponent DW is suggested to replace the traditional inert powders in suppressing biomass explosions.