玉米真空干燥特性的实验研究

研究了供热温度、真空度、物料层厚度等对玉米干燥速率，裂纹率和发芽率的影响。实验结果表明，提高供热温度使干燥速率加快，但玉米裂纹率增加，发芽率下降；真空度对干燥速率的影响主要表现在干燥的初始阶段，压力越低，初始的干燥速率越大；料层厚度的增加使干燥时间增加，但在一定厚度内提高了设备的干燥强度；初始水分低的玉米，干燥后的裂纹率和发芽率要好于初始水分高的玉米。综合分析实验结果，对于初始水分较高（37％）的玉米可以采用真空度为9000Pa，供热温度为70℃的干燥条件；而对于初始水分为25％的玉米可以采用真空度为9000Pa，供热温度为80℃的干燥条件；两者可选5cm为参考料层厚度，以保证干燥后玉米的品质和较高的干燥效率。     

带辐射的真空冷冻联合干燥系统的实验研究

设计了一套带辐射的真空冷冻干燥系统实验装置,以对虾为物料,进行干燥过程实验,分析研究干燥过程随辐射温度、真空度、含水率及时间等参数的变化规律。实验结果表明:物料中水份的升华干燥阶段与解析干燥阶段具有明显的转折点;辐射温度主要影响升华干燥阶段的水份升华速率,对于解析干燥阶段的水份升华速率只有略微影响,因此较低的辐射温度即能满足解析干燥的要求。     

核壳型复合乳胶膜干燥速率的研究

采用饥饿态加料的两阶段乳液聚合法,制备了由苯乙烯-丙烯酸丁酯无规共聚物和甲基丙烯酸甲酯-丙烯酸丁酯无规共聚物组成的核壳型复合乳液,测定了该复合乳液成膜过程中水的蒸发速率,根据干燥速率的变化将苯丙核壳型乳液的成膜过程分为3个阶段.此外,考察了不同温度、压力、固含量、乳化剂用量、AAc用量、壳层玻璃化转变温度等因素对乳液的失水量、干燥速率的影响.结果表明,增加温度、降低压力可显著增加乳液的失水量和干燥速率;而改变其它因素仅仅影响失水量但不影响恒速干燥速率.     

振动流化干燥技术的研究

在卧式，连续型振动流化干燥装置上，详细考察了活性炭和阳离子交换树脂的干燥过程，及其空气动力学，传热和干燥特性，所取得的规律性认识，对于工艺过程的参数选取有指导意义。     

载惰性颗粒喷动—气流干燥的实验研究

在实验室条件下研究了ＭｎＯ２浆料在载有惰性颗粒（玻璃珠）的喷动－气流干燥器中的温度，气流速度等条件对传热速率，产品含水和物料停留时间的影响，确定了这种干燥装置的适宜操作条件。     

胡萝卜热泵干燥特性及动力学模型分析

目的 优化胡萝卜的热泵干燥工艺,并提升胡萝卜干燥后的品质。方法 研究干燥初始温度、干燥温升值和切片厚度对胡萝卜热泵干燥特性的影响,并探讨上述条件与有效水分扩散系数和干燥活化能的关系。确定可以精确预测胡萝卜热泵干燥时含水率变化的干燥动力学模型,进而预测胡萝卜在不同热泵干燥条件下的体积变化规律。结果 干燥速率的变化与初始干燥温度、温升值的变化呈正相关,与切片厚度呈负相关;胡萝卜在热泵干燥过程中表现为降速过程,其中,切片厚度对干燥速率的影响最大,温升值对干燥速率的影响最小;对比分析了4种薄层干燥模型,Page模型能更好地描述胡萝卜的热泵干燥过程和水分迁移规律,模型所得拟合值相对于试验值的平均误差为5.76%;在此次试验范围内,胡萝卜的有效水分扩散系数介于3.0401×10^-10～7.1555×10^-10m²/s之间。该系数随着干燥温度的提高、温升值的增大及切片厚度的减小而呈增加的趋势。通过Arrhenius方程计算得到该试验条件下胡萝卜的干燥活化能为13.374 kJ/mol。结论 Page模型能够更好地预测胡萝卜在热泵干燥过...     

浅析气源干燥处理的方法及应用

本文介绍了压缩空气干燥装置类型和特点，并在探论其应用的基础上，重点介绍了某特定容器产品的所用无热再生式压缩空气干部处理装置的应用背景、工作原理和设计特点。     

干燥温度对萝卜品质的影响及动力学模型建立

目的采用热风干燥的方式,优选出对萝卜最适的干燥温度。方法通过测定不同干燥温度下萝卜的含水率和干燥速率,绘制热风干燥曲线和失水速率变化曲线,测定复水比、总糖含量和维生素C含量,并观察萝卜的微观结构。结果当萝卜的干燥温度为70℃时,复水比值为2.01,总糖的质量分数为2.21%,维生素C的含量为112.4mg/kg。萝卜热风干燥的动力学模型满足Page方程:M_R=e~(-rt~N),其中r=e~(0.7078-0.0079θ+0.0003θ~2),N=0.7658-0.0057θ+0.0002θ~2。结论当干燥温度为70℃时,能较好地维持萝卜的品质,建立的模型也能描述萝卜干燥过程中的水分变化。     

射流冲击流化床干燥的试验研究

设计试制了一种可对颗粒物料进行连续与批式干燥的射流冲击综合试验装置。在此基础上，对颗粒物料射流冲击1二燥进行了系统试验研究，得出了射流冲击干燥装置的结构参数、工艺参数与干燥机性能问的关系，建立了射流冲击干燥的数学模型。     

纳米结构材料在锂离子电池中的应用进展

设计试制了一种可对颗粒物料进行连续与批式干燥的射流冲击综合试验装置。在此基础上，对颗粒物料射流冲击干燥进行了系统试验研究，得出了射流冲击下燥装置的结构参数、工艺参数与干燥机性能间的关系，建立了射流冲击干燥的数学模型。     

Spray Drying of Aqueous Solutions of Inorganic and Organic Materials

Since the characteristics of the solution and the hot drying air have major influence on the physical, structural, and granulometric properties of the powders obtained by spray drying, it is very important to properly select the process conditions which will result with the formation of a powder of desired properties. For that reason, the influence of process conditions on the properties of the powders produced by spray drying has been investigated on a laboratory scale. The aqueous solutions of two organic (glycine and pentaerythritol) and three inorganic (sodium chloride, potassium chloride and potassium sulfate) materials have been chosen. During very fast spray drying it is impossible to distinguish individual steps of simultaneous processes (crystallization and drying). Knowledge of solubility data and crystallization kinetics of selected materials may help to explain what happens during spray drying.

The experiments have been performed at different drying air temperature, flow rate of the solution and of the spraying air. The obtained powders are mostly crystalline and agglomerated. Investigated process conditions influence the polymorphic composition of glycine obtained by spray drying. In order to have real information about the granulometric composition of powders it is necessary to perform microscopic analysis of the obtained crystals.     

Evaporative Drying of Aqueous Dispersions of Solid Lipid Nanoparticles

Solid lipid nanoparticles (SLNs) have been proposed as alternative colloidal drug carriers. SLNs are obtained by dispersing warm oil-in-water microemulsions into cold water. The aim of this research was to investigate an evaporative drying process for aqueous dispersions of SLNs. For this purpose, a special apparatus, namely, a thermostatic minidesiccator having alumina as the drying medium, was designed to carry out the evaporative drying at a controlled temperature. Besides the water removal kinetics, the mean particle size and the size distribution of SLNs were measured during the drying with the aim of detecting the highest temperature at which the drying process can be carried out without significantly affecting the SLN average diameter. The SLN dispersions were evaluated with and without a hydrophilic excipient, commonly used as a cryoprotector (trehalose). The drying temperature of 10°C was found to be the most suitable for obtaining SLNs as a powder, maintaining almost the same size as that of the SLNs in dispersion.     

Determination of the kinetic curves of drying of blocks of adsorbents-dessicants with different cross sections of channels and of a granulated adsorbent on a change in the flow velocity

The kinetics of convective drying (regeneration) of different types of adsorbents-dessicants with different geometric parameters has been studied. It is shown that adsorbents of a “channel” (cellular) type have a long constant-rate stage of drying, whereas a granulated polydisperse adsorbent is mainly dried at a variable rate. Adsorbents having a maximum water yielding capacity have been revealed. It has been established that the velocity of a drying gas flow substantially influences the process of moisture extraction from all types of adsorbents. In order to describe the kinetic curves of the given phenomenon, a model of a relaxation kinetic equation that quite satisfactorily describes the kinetics of drying of the adsorbents studied was used. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 82, No. 1, pp. 65–68, January–February, 2009.     

Rehydration ratio of fluid bed-dried vegetables

Fluid-bed drying of vegetable pieces has been investigated. The vegetables used have been potatoes, parsley roots, celery roots and carrots of various dimensions. Starting water content was: potatoes 78%, parsley roots 85.1%, celery roots 93.6%, and carrots 88.6%. Temperatures of fluidisation have varied from 60‡ to 100‡C at velocities of 0.71 ms^-1. The goal has been to obtain dry vegetables with 6% to 10% water content and of good rehydration quality. Experimental data (bed height, gas temperature and velocity, pressure drop over the bed, drying time) have been measured and relevant values have been calculated. The results have shown that drying of vegetables in a fluidized bed produces dry vegetable pieces of excellent quality in a much shorter time than in continuous belt-dryers which are generally used     

Drying of Rubber Wood Sawdust Using Tray Dryer

The present study attempts to understand drying characteristics of rubber wood sawdust in a tray dryer as it is the simplest and oldest of the dryers known commercially. An increase in temperature, flow rate of the heating medium, and initial moisture content was found to increase the drying rate. However, an increase in the particle diameter and bed height was found to reduce the drying rate. The increase in drying rate with temperature and moisture content was attributed to increase in the diffusion coefficient, while the increase due to the flow rate is attributed to reduction in the external mass transfer resistance during early stages of drying while the drying rate was high. An increase in bed height as well as particle size increases the diffusion path length for moisture, which contributes to the reduction in drying rate. The experimental data were modeled using Fick's diffusion equation, and the effective diffusivity coefficient was evaluated by minimizing the error between the experimental data and the prediction using the model equation. The effective diffusion coefficient was found to increase with increase in temperature, initial moisture content, and the flow rate of the heating medium, while it was found to decrease with increase in particle size. The diffusion coefficient was not found to vary with the bed height/solid loading. The effective diffusion coefficient was found to vary within 9.1 × 10^-9to 22 × 10^-9 m²/min. The standard deviation of error between the experimental data and prediction using the model, using the estimated effective diffusivity coefficient, was found to be less than 0.07 for the entire set of data, indicating the appropriateness of the model in predicting drying kinetics.     

基于厚度变化的纸浆模塑模内干燥特性研究

目的 探究模内干燥纸浆模塑制品厚度变化规律及干燥特性。方法 使用纸浆模塑成型机在不同干燥温度下，对3种不同初始厚度的纸浆模塑制品进行热压干燥实验，对实验所得产品的厚度变化和质量变化数据进行分析，并绘制干燥特性曲线。结果 纸浆模塑制品热压干燥过程可分为预压阶段、恒速干燥阶段和降速干燥阶段3个过程。在预压阶段，蓬松的纸浆模塑湿坯被模具挤压致密，厚度值出现瞬时减薄的趋势，减厚率高达40%以上，在恒速及降速阶段厚度则会逐步递减至一个平衡值。结论 根据实验结果获得了基于厚度变化的纸浆模塑制品的干燥特性。     

韭菜花酱热泵干燥特性及干燥数学模型研究

目的 研究韭菜花酱热泵干燥特性,并建立其干燥动力学模型。方法 以韭菜花酱为实验材料,对其进行热泵干燥处理,研究不同风温、风速、装载量、铺料厚度对韭菜花酱干燥时间和速率的影响,并根据实验数据对干燥模型进行非线性回归。结果 韭菜花酱热泵干燥过程无明显恒速阶段,当风温升高、风速增大时,干燥速率增大,干燥时间缩短,物料的色泽和气味会受到较大影响,干物料品质会降低;增大铺料厚度能显著地降低干燥速率,延长干燥时间。在所有实验工况下,Midilli模型预测的数据和实验数据拟合结果较好。结论 风温、风速、装载量和厚度均会不同程度地影响韭菜花酱热泵干燥过程,Midilli模型是描述韭菜花酱干燥过程中水分变化规律的最优模型。     

“Salt in a porous matrix” sorbent and sawdust as air driers for ventilation systems

The processes of moisture desorption by a sorbent-drier of the type of “salt in a porous matrix” and sawdust in convective flow, as well as under the acoustoconvective action, have been investigated. It has been shown that at a flow velocity of 31 m ⁄ sec the sorbent has a rather prolonged drying stage with a constant rate, and at a flow velocity of 13 m ⁄ sec this drying stage ends faster. It has been established that the velocity of the convective flow strongly influences the drying process of the sorbent, and the action of the acoustic field therewith produced no marked effect on the drying process. Moisture desorption from sawdust proceeds with a variable rate, and its intensity markedly increases under the action of the acoustic field. The influence of acoustic vibrations on the rate of moisture removal has a nonmonotonic character. The kinetics of the process of humidification of the sorbent-drier has been investigated. On the basis of the investigations made, a basic circuit for ventilating closed rooms by dried air with the use of sawdust or an IK-011-1 sorbent-drier has been proposed. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 82, No. 2, pp. 252–257, March–April, 2009.     

小型太阳能热泵联合干燥系统的设计与分析

根据湛江市的气候条件,设计了小型的太阳能热泵联合干燥装置,并对该装置的热泵单独运行和太阳能热泵联合运行的制热系数进行了讨论,结果表明太阳能热泵联合运行可以提高热泵系统的制热效率。     

冻结过程与冷冻干燥的关系

冷结干燥是一种高能食品保存方法,其中的干燥过程与冻结过程密切相关,优化冻结过程是降低能耗的途径之一。分析了溶液制品的冻结过程和影响冻结制品结构的因素,探讨了冷冻干燥过程中冻结与干燥的关系以及提高干燥速率的方法。