Numerical investigation on freeze-drying of aqueous material frozen with pre-built pores

来源 :Chinese Journal of Chemical Engineering | 被引量 : 0次 | 上传用户:wangfei871010
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
Freeze-drying of the initially porous frozen material with pre-built pores from liquid material was found experimentally to save drying time by over 30% with an initial saturation being 0.28 compared with the conventional operation with the initial saturation being 1, using mannitol as the solid material. In order to understand the mass and heat transfer phenomena of this novel process, a two-dimensional mathematical model of coupled mass and heat transfer was derived with reference to the cylindrical coordinate system. Three adsorption–desorption equilibrium relationships between the vapour pressure and saturation value namely, power-law, Redhead’s style and Kelvin’s style equation, were tested. Kelvin’s style in exponential form of adsorption equilibrium relation gave an excellent agreement between the model prediction and experimental measurement when the equation parameter, γ, of 5000 was applied. Analyses of temperature and ice saturation profiles show that additional heat needs to be supplied to increase the sample temperature in order to promote the desorption process. Simulation also shows that there is a threshold initial porosity after which the drying time decreased with the increase in the initial porosity. Enhanced freeze-drying is expected to be achieved by simultaneously enhancing mass and heat transfer of the process. Freeze-drying of the initially porous frozen material with pre-built pores from liquid material was found experimentally to save drying time by over 30% with an initial saturation being 0.28 compared with the conventional operation with the initial saturation being 1, using mannitol as the solid material. In order to understand the mass and heat transfer phenomena of this novel process, a two-dimensional mathematical model of coupled mass and heat transfer was derived with reference to the cylindrical coordinate system. Three adsorption-desorption equilibrium relationships between the vapor pressure and saturation value namely, power-law, Redhead’s style and Kelvin’s style equation, were tested. Kelvin’s style in exponential form of adsorption equilibrium relation gave an excellent agreement between the model prediction and experimental measurement when the equation parameter, γ, of 5000 was applied Analyzes of temperature and ice saturation profiles show that additional heat need s to be supplied to increase the sample temperature in order to promote the desorption process. Simulation also shows that there is a threshold initial porosity after drying time decreased with the increase in the initial porosity. by simultaneously enhancing mass and heat transfer of the process.
其他文献
如今印刷行业各类数字技术层出不穷.使得印刷数字化战场硝烟四起,但尘埃落定后哪些才是会对印刷行业产生最深远影响的新生代数字技术呢?也许,7月16日刚刚出炉的2008年度 Inte
该文从挂篮荷载计算、施工流程、支座及临时固结施工、挂篮安装及试验、合拢段施工、模板制作安装、钢筋安装、混凝土的浇筑及养生、测量监控等方面人手,介绍了S226海滨大桥
该文从挂篮荷载计算、施工流程、支座及临时固结施工、挂篮安装及试验、合拢段施工、模板制作安装、钢筋安装、混凝土的浇筑及养生、测量监控等方面人手,介绍了S226海滨大桥
该文从挂篮荷载计算、施工流程、支座及临时固结施工、挂篮安装及试验、合拢段施工、模板制作安装、钢筋安装、混凝土的浇筑及养生、测量监控等方面人手,介绍了S226海滨大桥
南京紫藤制版印务公司(以下简称南京紫藤印务)成立于1996年,是以出版物设计制作、排版印刷为主的专业印务公司.自成立以来,南京紫藤印务始终坚持“精心设计、细心制作、热心
该文从挂篮荷载计算、施工流程、支座及临时固结施工、挂篮安装及试验、合拢段施工、模板制作安装、钢筋安装、混凝土的浇筑及养生、测量监控等方面人手,介绍了S226海滨大桥
The removal of copper ions from wastewater by ion exchange has been studied using an iminodiacetate resin.The capacity of the resin for the copper ions has been
介绍了用相对漏磁法推导自耦有载旁柱调压变压器电抗电压的计算方法.
介绍了光电式电流互感器的一种类型--混合式光电电流互感器的传感头采样线圈,即Rogowski线圈的原理、结构及实验结果.
该文从挂篮荷载计算、施工流程、支座及临时固结施工、挂篮安装及试验、合拢段施工、模板制作安装、钢筋安装、混凝土的浇筑及养生、测量监控等方面人手,介绍了S226海滨大桥