桉木屑颗粒燃料固体桥结构构建与燃烧特性研究OA北大核心CSTPCD

It is an effective way to improve the physical properties of biomass pellets by constructing"solid bridge"structures inside the pellets.A way of constructing"solid bridge"structured pellets was proposed by blending different particle sizes from one material.The construction scheme was set to add eucalyptus sawdust with(4 mm,5 mn]particle size into eucalyptus sawdust with(0,1 mm]particle size.The blending amount(referred to mass fraction of material with(4 mm,5 mm]particle size in the total materials)was 0,1％,3％,5％,7％,10％,15％,20％,25％,30％,40％and 100％,respectively.The cross-sectional structures of the made pellets showed that with 5％～10％blending amount,a proper amount of"solid bridge"structures can be constructed by long fiber particle mechanical interlocking.Under this condition,short fiber particles were filled among these mechanical interlocks sufficiently and thus the pellet possessed particle tightly arrangements.The appropriate blending amount was 5％,under which condition the relaxed density,Meyer hardness and specific energy consumption of the pellets reached the relatively higher,the highest and the lowest values of 1 074.79 kg/m3,23.93 MPa and 27.06 kJ/kg,respectively.Meanwhile,the equilibrium moisture content and moisture absorption rate of the pellets was 11.65％and 0.015 3 min-1,respectively.Then,the heating value analysis given the information that the structured pellets maintained the same higher heating value as the eucalyptus sawdust,which was 18.44 MJ/kg.At the heating rates of 10～40℃/min,the ignition temperature of pellet combustion(with 5％blending amount)was evaluated at 246.60～265.00℃,the burnout temperature was measured at 504.40～508.40℃,the maximum mass loss rate was assessed at-6.84～-29.10％/min,and the mean mass loss rate was calculated at-6.84～-29.10％/min,the integrated combustion index was determined at 7.26×10-12～1.09 ×10-10 min-2·K-3.Besides,the slagging and fouling indices predicted a high or medium tendency for combustion.