硫酸铵微波干燥特性及动力学模型分析

采用微波干燥技术进行了硫酸铵干燥的研究.通过系统实验分析了硫酸铵微波干燥特性,并采用薄层干燥模型进行数值分析.结果表明:修正Page模型(Ⅱ)较之其他模型更适于薄层硫酸铵微波干燥的模拟.应用Fick第二定律得到微波功率230-700 W,物料质量150-300 g条件下薄层硫酸铵微波干燥的有效扩散系数的变化范围分别为:...     

城市污泥热风与微波干化特性研究

采用热风和微波加热两种方式对城市污泥进行薄层干化实验研究,分别考察污泥薄层厚度和其他操作条件对污泥干燥特性及能耗的影响。研究发现:在热风干燥过程中,由于污泥的塑性,污泥表面容易结壳,从而严重阻碍了水分向外迁移,使得干燥速率呈阶梯状下降。微波干燥污泥具有时间短、干燥速率大,同时节省能源。     

干燥动力学研究综述

对现有的几种干燥速率定义及其数学表达式进行了分析和比较。简述了多孔介质的干燥动力学特性及其湿分迁移机理。对薄层干燥的半理论模型、半经验模型和经验模型作了评述。     

颗粒状氯化天然橡胶穿透式干燥动力学模型

本试验通过氯化天然橡胶的薄层干燥试验,探讨风温、风速以及粒径对CNR含水量的影响规律,建立薄层干燥方程。试验结果表明,预测值与实测值一致性较好,所建数学模型可用于描述氯化天然橡胶的薄层干燥。     

油页岩干燥特性实验研究

以柳树河油页岩颗粒为原料,在恒温介质干燥器内进行油页岩干燥动力学研究,考察干燥介质温度和颗粒直径对油页岩干燥性能的影响,采用薄层干燥模型中的Lewis模型,对油页岩干燥实验数据进行模拟,确定油页岩干燥方程和干燥速率方程,建立油页岩干燥常数表达式。研究结果表明:薄层干燥模型中Lewis模型能较好的描述油页岩在恒温介质干燥器内的干燥过程;其干燥过程主要发生在降速干燥阶段;200℃时油页岩无性质变化,干燥达到平衡时,油页岩含水量可降到0.5%左右,油页岩表观活化能为17～19kJ/mol。     

氢氧化铝薄层干燥的节能方法探讨

氢氧化铝的洞道式薄层干燥在生产中有重要应用，但要消耗大量的能量。对氢氧化铝的干燥的基础特性进行了研究，并着重探讨了变温干燥的节能方法。试验结果表明：氢氧化铝的洞道式薄层干燥主要由水分内部迁移控制，强化其干燥速率应着重从改善物料状况着手；并采用冷热风交替的干燥方法将取得较好的节能效果。这些工作对改进生产中的氢氧化铝的干燥方法具有一定的指导意义。     

木薯酒糟在旋转闪蒸干燥器中的干燥特性

对木薯酒糟在旋转闪蒸干燥器中的基本干燥特性进行了实验研究。结果表明该物料干燥后的含水质量分数与干燥介质温度呈直线关系 ,与干燥时间呈指数曲线关系 ,这一特性与其薄层干燥过程相似。某些研究结果还为该物料的工业化干燥提供了依据     

番木瓜的自身特性及干燥温度对干燥特性的影响研究

对番木瓜片进行了热风薄层干燥实验,主要考察了番木瓜自身的不同条件(包括成熟度、厚度、形状)与干燥温度对干燥速率的影响,通过实验数据建立了番木瓜片的热风干燥的水分比与干燥时间关系的联系,根据Page模型进行了拟合检验,结果显示模型的预测值与实测值拟合良好。     

干燥数学模型和动态模拟进展

对近几年的干燥过程动态模拟的基本方法进行了总结.以干燥过程的薄层干燥理论为基础,进一步对深层干燥模型的建立作出详细解释,包括深层干燥模拟过程中物理模型、数学模型的确立原则,并对固定干燥床和传动干燥床分别进行了讨论.干燥动态模拟以热质传递为基础,利用热力学以及数值分析等相关知识,对物料内部的干燥情况进行了具体分析.最后,...     

碱式氯化镁纳米棒的干燥动力学研究

以六水氯化镁和轻质氧化镁为原料,采用液相法制得长度约为10μm、直径为100～150hm的碱式氯化镁纳米棒。通过干燥动力学实验得到碱式氯化镁纳米棒的干燥曲线和干燥速率曲线。采用薄层干燥模型及热分析动力学对干燥动力学实验数据进行数学处理,获得碱式氯化镁纳米棒的干燥方程、干燥速率方程、指前因子A和表观活化能E。     

Emerging food drying technologies with energy-saving characteristics: A review

Abstract

Drying is one of the most vital preservation techniques used in the food industry. It demands different levels of energy to produce commercially high-quality-dried food products. Novel drying technologies minimize deterioration of the food ingredients and produce novel products for consumers. In recent years, there have been many developments in the technology connected with the industrial drying of foods. Recent research has shown that novel food drying technologies could be utilized to improve the efficiency of drying by lowering the energy consumption and also to enhance the product quality. This article reviews selected energy- saving techniques in drying and discusses some novel combined drying technologies. These include solar-assisted, infrared-assisted, microwave-assisted and similar hybrid drying methods for food drying. Recommendations are also made for future research and development.     

Effects of Different Drying Methods on the Quality Changes of Granular Edamame

In this article, the quality changes of the granular fruits and vegetables dried by vacuum microwave drying, freeze drying, hot air drying, and combined hot air-vacuum microwave drying are investigated, and the quality parameters compared on the basis of vitamin C and chlorophyll contents, shrinkage and rehydration capacity, color, texture, and microstructure changes. The quality parameters of products dried by vacuum microwave drying are slightly lower than those obtained by freeze drying, but much better than those obtained using conventional hot air drying. The quality characteristics of product dried by combined hot air-vacuum microwave are significantly improved compared to those simply hot air-dried.     

Effects of Different Drying Methods on the Quality Changes of Granular Edamame

In this article, the quality changes of the granular fruits and vegetables dried by vacuum microwave drying, freeze drying, hot air drying, and combined hot air–vacuum microwave drying are investigated, and the quality parameters compared on the basis of vitamin C and chlorophyll contents, shrinkage and rehydration capacity, color, texture, and microstructure changes. The quality parameters of products dried by vacuum microwave drying are slightly lower than those obtained by freeze drying, but much better than those obtained using conventional hot air drying. The quality characteristics of product dried by combined hot air–vacuum microwave are significantly improved compared to those simply hot air–dried.     

微型多功能干燥实验机的研制

微型多功能干燥实验机是新推出的一款专利产品，可在单机上实现流化床干燥、喷雾干燥、喷雾造粒、蒸发浓缩、蒸发结晶、气流干燥等多种工艺过程，且占地面积小于0．5m^2，水分蒸发量可达1kg／h；采用PLC自动控制系统。可对进出风温度、风量等进行设定与自动控制。适合于大学、科研院所、企业等从事新产品研发与昂贵产品的实验研究。     

亚麻胶的喷雾干燥技术

研究了亚麻胶水溶液的各种喷雾干燥特性（工艺）。试验结果表明离心喷雾干燥为最佳的亚麻胶干燥方法。干燥产品具有粘度高，色泽好，颗粒均匀，流动性好，溶解性好等特点。     

干燥系统的设计分析模拟软件

对现有的干燥过程模拟商业软件做了简要回顾。这些软件在用于设计、分析、故障排除以及控制与优化干燥系统中可大大降低成本。推荐并分析了一款新的干燥分析软件（Simprosys）。讨论了该软件产品成功的关键因素,并介绍了该软件开发的动机和原理及其应用。     

A Two-Stage Vacuum Freeze and Convective Air Drying Method for Strawberries

Strawberries were dehydrated in a two-stage combination drying consisting of vacuum freeze drying (FD) followed by hot air drying (AD), and in a two-stage hybrid method involving FD and finish AD(FAD) to obtain dehydrated strawberries of high quality at reduced cost. Energy consumption and physicochemical properties of the FAD product were compared with single-stage AD and single-stage FD. The quality parameters of the products were also analyzed. It was found that the quality of combined FAD-dried products approximated that of single-stage FD. Hence, the proposed two-stage combination drying method is recommended for dehydration of strawberries to obtain a high-quality product at lower cost when compared with vacuum freeze drying alone.     

A Two-Stage Vacuum Freeze and Convective Air Drying Method for Strawberries

Strawberries were dehydrated in a two-stage combination drying consisting of vacuum freeze drying (FD) followed by hot air drying (AD), and in a two-stage hybrid method involving FD and finish AD(FAD) to obtain dehydrated strawberries of high quality at reduced cost. Energy consumption and physicochemical properties of the FAD product were compared with single-stage AD and single-stage FD. The quality parameters of the products were also analyzed. It was found that the quality of combined FAD-dried products approximated that of single-stage FD. Hence, the proposed two-stage combination drying method is recommended for dehydration of strawberries to obtain a high-quality product at lower cost when compared with vacuum freeze drying alone.     

卫生陶瓷坯体干燥技术的发展

本文从干燥的方式、设备、制度、操作以及特异型产品的干燥等方面介绍了国内卫生陶瓷坯体干燥技术的发展情况,并分析了影响干燥质量的因素。     

QUALITY INTERACTION IN A JET SPOUTED BED DRYER FOR BIO-PRODUCTS

An experimental study was conducted to apply the jet spouted bed (JSB) dryer with inert bodies for drying of fodder antibiotic; (zinc-salt bacitracin and tylosin) and baker's yeast which are extracted from fermentation broth. After establishing the drving properties of these products (e.g. sorption isotherm, water activity and thermostability), the influence of basic drying parameters (temperature of drying agent, bed loading, gas flow rate) on drying characteristics and quality of the products was determined. The results proved that a JSB dryer may be successfully applied to fodder antibiotics; especially to Zn-bacitracin; however, for a highly labile live organism like baker's yeast, this method cannot be used. The optimal parameters for drying of Zn-bacitracin have been presented.