【摘要】 在传统流化床内,加入中空水平螺旋叶片,其内通入饱和蒸汽。对粒度分布很广的褐煤物料,借助气力和机械力联合作用,建立一种新型的内热式移动-流化床干燥模型。研究了操作气速、进口气体温度、机械力作用强度等因素对褐煤干燥过程的影响。采用因次分析的方法,建立了气固间传热系数关联式。实验结果表明,机械力场的加入,使床层内形成了稳定的大小颗粒共存的气固两相流场,并使干燥速率增大,传热系数增大。其中,叶片转速在3.33~5.40r/min范围时,传热系数增大了约35%。叶片内饱和蒸汽以内热源的形式,通过叶片传导换热,大大强化了传热和干燥效果。在其他条件不变的情况下,传热量增加了约45%。更多还原

【Abstract】 The hollow horizontal spiral blade where saturated steam flows was equipped in the conventional fluidized-bed.A new moving-fluidized bed drying model for large particles size distribution of lignite materials with internal heat was established,under combined pneumatic and mechanical force.The influence of factors such as operating gas velocity,inlet gas temperature and mechanical force strength on the lignite drying process were analyzed,and the relative formula of heat transfer coefficient was established by dimensional analysis method.The experimental results showed that the mechanical force formed a stable gas-solid flow field with all size particles coexisted,increased the drying rate and the heat transfer coefficient.And in the range 3.33—5.40 r/min of the blade speed,heat transfer coefficient increases by about 35%.The saturated steam within the blade in the form of the internal heat source conducts heat through the blade,greatly strengthened the effect of heat transferring and drying.In the case of other conditions unchanged,the capacity of heat transmission improved by about 45%.更多还原