林业剩余物棒状燃料的成型技术研究

对不同林业剩余物的棒状燃料的成型技术进行研究,重点分析进料间隙和进料速度对不同材性、粒度的林业剩余物的成型效果.结果表明：1）所有的林业剩余物只要将其含水率控制在15％～25％之间,最大粒度的宽、厚规格不超30 mm,通过调整进料间隙和速度均可加工成棒状燃料.2）进料间隙与原料粒度呈负相关,进料速度又与进料间隙呈负相关.即木屑、竹屑等粒度小的物料进料间隙要大,可调至4～5 mm,进料速度应控制在中速或中速以下（电机频率为6Hz或6 Hz以下）;而杂灌、油茶果壳等粒度较大的物料进料间隙要小,可调至1～3 mm,进料速度应控制在较高速或高速间（电杌频率为8～11 Hz）.3）成型燃料的密度取决于成型时的压力.通过选用孔长径比大的环模或控制进料间隙和进料速度来调节成型时的压力,可使不同林业剩余物的棒状燃料密度达到1 g/cm3以上.4）原料的物质组成和性质是成型燃料热值的决定因素.锯末、竹屑的棒状燃料热值在4 000 kcal/kg左右,而杂灌和油茶果壳一般在4 000 kcal/kg以下.

Study on Molding Technology of Rod-like Biofuel of Forest Residues

The molding technology of rod-like biofuel of different forest residues was studied and the molding effect of feeding gap and feeding rate on different wood properties and particle size was mainly analyzed. The results showed that all of forest residues can be moldied by adjusted feeding gap and feeding rate when containing water ratio was 15%-25% and particl diameter was not exceeded 30 mm. Secondly, feeding gap was negative correlated with particle size and feeding rate. The molding of sawdust and bamboo chips, little particle size, was under large feeding gap （4-5 mm） and middle feeding rate that motor frequency was 6 Hz or below 6 Hz. While the molding of miscellaneous shrubs and fruit shell of Camellia oleifera, large particle size, was under small feeding gap（1-3 mm） and high feeding rate that motor frequency was 8-11 Hz. In addition, density of rod-like biofuel depended on molding pressure. The densities of rod-like biofuel of different forest residues can exceed 1 g/ cm^3 by adjusted molding pressure, by using loop die of large length and diameter ratio or controlling feeding gap and feeding rate. Finally, material composition and property of forest residues were the determinants of caloric value of rod-like biofuel. The caloric value of rod-like biofuel of forest sawdust and bamboo chips was about 4 000 kcal/kg, and the caloric value of rod-like biofuel of miscellaneous shrubs and fruit shell of C. oleifera was below 4 000 kcal/kg.