Effect of Feedstock Water Leaching on Ignition and PM1.0 Emission During Biomass Combustion in a Flat-Flame Burner Reactor

In this work, the effects of feedstock water leaching on ignition and PM1.0 emission during biomass combustion were studied, for the first time, in a Hencken flat-flame burner reactor (HFFBR). A high-speed video camera and high-resolution electrical low-pressure impactor were respectively employed to diagnose ignition and PM1.0 along the height of the burner. The mineral composition of PM10+ was measured as a function of height to demonstrate the potassium release during the early stage of biomass combustion. The results show that water leaching does not change the functional group of the biomass (straw), but increases the BET surface area and pore volume. Water leaching removes 90% of the potassium and all the chlorine, reducing the same amount of PM1.0 emission. The effect of water leaching on ignition delay observed in the flat-flame burner reactor agrees with the delay of biomass-devolatilization in TGA. Profiles of mineral composition in the PM10+ with height shows that a large amount of the potassium is released before biomass ignition. This indicates that, at realistic heating rates, the catalytic promotion of water-soluble minerals on biomass ignition is primarily through promoting devolatilization. The ignition delay of biomass particles caused by water leaching is more significant at lower temperature, e.g., ignition is delayed from 20 to 24 ms at 1000 degrees C. and from 9.2 to 10.2 ms at 1300 degrees C. (C) 2018 The Combustion Institute. Published by Elsevier Inc. All rights reserved.