关键词: 褐煤, 流化床, 气固两相流, 干燥, 传热

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 3.33-5.40r/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%.

Key words: lignite, fluidized-bed, gas-solid flow, heat transfer, drying