初始非饱和多孔物料对冷冻干燥影响理论分析  

Theoretical analysis for freeze-drying of initially unsaturated porous material

作　　者：王维[1,2] 陈墨[3,4] 王威[3] 潘艳秋[3] 陈国华[5] 

机构地区：[1]大连理工大学化工机械学院,辽宁大连116024 [2]大连民族学院生命科学学院,辽宁大连116600 [3]大连理工大学化工学院,辽宁大连116024 [4]大连市第四人民医院职业卫生科,辽宁大连116001 [5]香港科技大学化学与生物分子工程系

出　　处：《大连理工大学学报》2014年第1期6-12,共7页Journal of Dalian University of Technology

基　　金：国家自然科学基金资助项目(21076042);中央高校基本科研业务费专项资金资助项目(DUT14RC(3)008)

摘　　要：为提高过程的经济性,提出了液体物料初始非饱和冷冻干燥的技术思想．推导了冷冻干燥质、热耦合传递模型,模型采用了新的吸附-解吸平衡关系,并考虑了吸湿效应．控制方程用有限容积法进行数值求解．待干水溶液中的溶质选用典型的药物赋形剂——甘露醇．结果表明,初始非饱和多孔物料能够显著减少干燥时间,达到强化冷冻干燥的目的．随初始孔隙率 ε_0（1-S_0） 的不断增大,干燥时间逐渐缩短；在物料初始饱和度 S_0为0.30~0.35时,干燥时间达到最短．依据干燥过程中饱和度和温度的分布,分析了物料内部质、热传递机理和干燥速率控制因素．对有效质量扩散系数 K_S 和有效导热系数 λ＋K_T ΔH 的分析显示,随着冷冻干燥的进行,物料瞬时孔隙率 ε_0（1-S） 不断增大,过程将由传质控制逐渐变为传热控制．To improve the process economy ,freeze-drying of initially unsaturated frozen material from aqueous solution is put forward in the present investigation .A novel heat and mass transfer model of freeze-drying with hygroscopic effect was derived on the basis of a new adsorption-desorption relationship .The finite-volume method was adopted in solving the governing equations .Mannitol ,a typical pharmaceutical excipient , was selected as the solute in aqueous solution to be dried . Experimental results show that the freeze-drying process can be enhanced indeed using the initially unsaturated frozen material ,and drying time decreases with increase in the initial porosity ,ε0 （1 -S0 ） .There is the shortest drying time in correspondence with about 0 .30-0 .35 of initial saturation , S0 .According to the profiles of temperature and saturation ,heat and mass transfer mechanism was discussed and the drying rate-controlling factor was analyzed . Inspection on the effective mass diffusivity ,KS and the effective heat conductivity ,λ＋ KTΔH displays that the rate-controlling factor would change from mass transfer to heat transfer with increase in instantaneous porosity ,ε0 （1-S） .

关 键 词：初始非饱和 冷冻干燥 数值模拟 传热传质 多孔介质 

分 类 号：TQ028.5[化学工程]