化工学报Issue(2)：25-32,8.DOI:10.11949/j.issn.0438-1157.20141065
具有初始孔隙的多孔物料冷冻干燥
Freeze-drying of porous frozen material with initial porosity
摘要
Abstract
Freeze-drying of porous frozen material with initial porosity was experimentally investigated. Mannitol was selected as the primary solute in aqueous solution to be dried. The liquid nitrogen ice-cream making method was used to prepare frozen materials with initial porosity. Freeze-drying experiments were performed using two kinds of frozen materials, the initially unsaturated one and the conventionally saturated one for comparison. Freeze-drying could be significantly enhanced with the initially unsaturated frozen material. SEM images of dried products showed that such prepared initially unsaturated material had larger void space and more tenuous solid matrix that was continuous and uniform than those with the conventionally saturated one. This would be beneficial to migration of sublimed vapor and reduction of mass transfer resistance. There was indeed an overall sublimation for the initially unsaturated frozen material, and a primary sublimation region still existed through examining temperature variations at different locations inside the material. Predominant drying rate-controlling factor was heat transfer for the initially unsaturated frozen material, and mass transfer for the conventionally saturated one. Operating pressure had little influence on the freeze-drying process. Combination of radiation heating with conduction heating was able to improve heat transfer in freeze-drying of initially unsaturated porous materials, further shortening drying time.关键词
冷冻干燥/初始饱和度/干燥曲线/组合加热/传质/传热Key words
freeze-drying/initial saturation/drying curve/combination heating/mass transfer/heat transfer分类
化学化工引用本文复制引用
赵延强,王维,潘艳秋,单宇,于凯,陈国华..具有初始孔隙的多孔物料冷冻干燥[J].化工学报,2015,(2):25-32,8.基金项目
中央高校基本科研业务费专项资金（DUT14RC（3）008）；国家自然科学基金项目（21076042）。 （）
