固态食品常压流态化冷冻干燥的研究

至今为止,冷冻干燥技术得到应用的只有真空冷冻干燥一种,本文提出了常压吸附剂流化冷冻干燥,并具体阐述了数学和实验装置。通过与真空冷冻干燥进行比较,认为常压吸附流化冷值得进一步深入研究,具有发展和应用前景。     

常压吸附流化冷冻干燥技术的研究与探索

阐述了常压吸附流化冷冻干燥与真空冷冻干燥的原理、特点、研究概况和能耗分析,提出常压吸附流化冷冻干燥可能成为一种新型冷冻干燥技术而具有较高的研究开发价值.     

常压吸附流化冷冻干燥技术的研究与探索

阐述了常压吸咐流化冷冻干燥与真空冷冻干燥的原理，特点，研究概况和能耗分析，提出常压吸附流化冷冻干燥可能成为一种新型冷冻干燥技术而具有较高的研究开发价值。     

真空冷冻干燥在食品中的应用

介绍了真空冷冻干燥技术的原理、工艺流程和应用。通过水的相平衡图及三相点示意图。阐述了真空冷冻干燥技术的原理;分析了真空冷冻干燥过程中各阶段的特点;论述了真空冷冻干燥在食品加工中的应用。     

气凝胶制备的干燥技术

气凝胶是一种新型轻质的三维纳米多孔固态材料,由于其独特的物理化学性能,在许多领域存在潜在的应用价值而备受关注。本文简要介绍了湿凝胶的干燥理论和气凝胶的超临界干燥制备技术,评析了气凝胶的亚临界干燥、常压干燥、常压阶梯干燥及真空冷冻干燥等非超临界干燥制备技术。     

螺杆式制冷压缩机在真空冷冻干燥机中的最新应用

本文首先介绍了真空冷冻干燥的优点,真空冷冻干燥机的组成;其次叙述了传统真空冷冻干燥机所采用的制冷压缩机形式,以及最新应用的螺杆式制冷压缩机的优势及特点。     

真空冷冻干燥技术在生物制药种的应用

近些年来,我国生物制药行业的发展已经达到了顶峰,生物制药水平也越来越高,真空冷冻干燥技术在生物制药中也得到了广泛应用。就真空冷冻干燥技术进行分析,探讨出真空冷冻技术在我国生物制药当中的应用。对真空冷冻干燥的过程进行探讨,以此来提升我国的真空冷冻干燥技术,把真空冷冻干燥技术科学合理地融入到我国的生物制药中,发挥真空冷冻干燥技术的最大功效,从而提高我国的生物制药水平,保障人们的生活用药,解决好我国的民生问题,促进我国经济发展。     

螺杆式制冷压缩机在真空冷冻干燥机中的最新应用简

本文首先介绍了真空冷冻干燥的优点，真空冷冻干燥机的组成；其次叙述了传统真空冷冻干燥机所采用的制冷压缩机形式，以及最新应用的螺杆式制冷压缩机的优势及特点。     

我国真空冷冻干燥设备的发展趋势及其在石化领域的应用前景

本文主要介绍了真空冷冻干燥机的最近发展，及真空冷冻干燥技术在化工石油领域的应用。     

微波真空组合干燥在食品加工中的应用

微波真空组合干燥技术是将微波干燥和真空干燥或真空冷冻干燥技术结合起来,弥补了微波干燥过程中物料温度高导致热损伤、真空或真空冷冻干燥干燥时间长的缺点,使物料在较低温度下短时间内完成干燥过程,具有干燥温度低、营养成分损失少、干燥速度快等优点。本文针对微波真空冷冻干燥技术在食品加工中的应用,详细阐述了其干燥原理、干燥特点、干燥设备和未来的研究和发展方向。     

A STUDY OF THE PRIMARY PHASE OF FOOD FREEZE-DRYING IN VACUO

In the development of a novel freeze-drying technique in a fluidized bed at atmospheric pressure, a parallel study was undertaken using a conventional vacuum equipment. Two kinetically distinct phases were observed during freeze drying of representative Pood samples:

(1) a period during which the rate of drying was constant and (2) a second period during which the drying rate sufferedcontinual reduction. This paper focused attention on the primary drying period which corresponded with the kinetics of sublimation of pure     

ATMOSPHERIC FREEZE-DRYING PART 1 : DESIGN,EXPERIMENTAL INVESTIGATION AND ENERGY-SAVING ADVANTAGES

This paper describes the experimental study of a new process for freeze-drying based on a fluidized bed of dry adsorbent working at atmospheric pressure. Process feasibility has been demonstrated. The kinetics of dehydration have been established systematically for thin-sliced potatoes. A comparison has been carried out with vacuum freeze-drying. Processing time is longer than under vacuum freeze-drying, but energy savings of 35% can be expected from a continuous duty facility.     

NEW APPLICATIONS OF HEAT PUMPS IN DRYING PROCESSES

Heat pumps in combination with fluidized bed driers have been investigated extensively at The Norwegian Institute of Technology. A laboratory plant was constructed and a series of experiments on different types of temperature sensitive products were executed. By using heat pump, good temperature and humidity regulation is achieved. Drying temperatures can be regulated from -20°C to 50°C. This gives the possibility of freeze-drying at atmospheric pressure, and drying at temperatures above 0°C in the same plant. By using a temperature program, including an initial period of freeze drying, it is possible to regulate the products' physical properties. Examples are: the sinking velocity of fish fry feed, rehydration ability, colour and taste of dried fish, meat and vegetable products. Further, biotechnological products like bacterial cells and biomolecules/enzymes were dried with improved biological activity of the products compared to traditional drying methods like vacuum freeze drying or spray drying.     

A Review of: “FLUIDIZATION VI” Editors: J.R. Grace,L.W. Shemilt and M.A. Bergougnou Publisher: AIChE (for Engineering Foundation) 345 East 47th St., New York,N.Y. 10017, 1989, 750 p.

ABSTRACT

Heat pumps in combination with fluidized bed driers have been investigated extensively at The Norwegian Institute of Technology. A laboratory plant was constructed and a series of experiments on different types of temperature sensitive products were executed. By using heat pump, good temperature and humidity regulation is achieved. Drying temperatures can be regulated from ?20°C to 50°C. This gives the possibility of freeze-drying at atmospheric pressure, and drying at temperatures above 0°C in the same plant. By using a temperature program, including an initial period of freeze drying, it is possible to regulate the products' physical properties. Examples are: the sinking velocity of fish fry feed, rehydration ability, colour and taste of dried fish, meat and vegetable products. Further, biotechnological products like bacterial cells and biomolecules/enzymes were dried with improved biological activity of the products compared to traditional drying methods like vacuum freeze drying or spray drying.     

Drying of solids in vacuum fluidized bed

A drying process in a fluidized bed under vacuum conditions is experimentally and theoretically studied. A fluidized bed operating in reduced pressure presents a possibility for a better quality of production, with safer process conditions. A mathematical model is developed for the reduced‐pressure drying process in a fluidized bed. Some parameters were analyzed by comparing experimental results with model predictions. The predictions from the model agreed quite closely with the experimental data. The results showed that a decrease in pressure reduces the interparticular resistance. A good agreement was also found applying the model to data, at atmospheric pressure, from other authors.     

黑加仑真空冷冻与微波真空联合干燥工艺研究

以黑加仑为原料,对其进行了真空冷冻与微波真空联合干燥工艺的研究。结果表明：先真空冷冻后微波真空干燥（FDMV）的组合方式是可行的;联合干燥合理工艺参数为：微波功率1．34kW。绝对压力11kPa,转换含水率为20％（wb）;通过试验验证,联合干燥生产的脱水黑加仑的感官品质和营养成分接近真空冷冻干燥,联合干燥方式对节省干燥时间和降低能耗是有效的。     

Modeling of Vacuum Desorption in Freeze-Drying Process

A mathematical model of multicomponent vacuum desorption, which occurs in vacuum freeze-drying process, was developed. In freeze-drying porous biomaterials and pharmaceuticals are considered and the vacuum freeze-drying process, especially the moisture desorption in its final stage, is investigated. In this article, the drying with conductive heating and constant contact surface temperature was considered. Pressure drop is taken into account in the model formulation but was neglected in process simulation because of thin material layers undergoing freeze-drying. Model equations were solved by numerical method of lines. Moisture content and temperature distributions within the drying material were predicted from the model as a function of drying time.     

A novel atmospheric freeze dryer using simultaneous application of subzero and hot air streams using a vortex chiller

The objective of this research was to develop an atmospheric freeze-drying (AFD) system for heat-sensitive materials. A laboratory scale AFD system consisting of a vortex chiller was designed and fabricated. A vortex tube was used to convert compressed air into a subzero and a hot air stream. The system used the simultaneous application of subzero air stream and hot air carrier gas coupled with radiant heat input for drying heat-sensitive materials. A parametric evaluation of this drying system was performed. Comparison of drying characteristics and the physical quality (e.g., color, shape, size) with vacuum freeze and traditional AFD was also performed. Results revealed that the proposed system is a suitable and viable alternative without compromising the quality compared to traditional freeze-drying system.     

Modeling of Vacuum Desorption in Freeze-Drying Process

Abstract

A mathematical model of multicomponent vacuum desorption, which occurs in vacuum freeze-drying process, was developed. In freeze-drying porous biomaterials and pharmaceuticals are considered and the vacuum freeze-drying process, especially the moisture desorption in its final stage, is investigated. In this article, the drying with conductive heating and constant contact surface temperature was considered. Pressure drop is taken into account in the model formulation but was neglected in process simulation because of thin material layers undergoing freeze-drying. Model equations were solved by numerical method of lines. Moisture content and temperature distributions within the drying material were predicted from the model as a function of drying time.