二氧化硅微粉干燥系统干燥过程分析

介绍了采用旋转闪蒸干燥机进行二氧化硅微粉干燥的工作原理。并针对微粉物料的特性进行分析,合理配置干燥系统。通过对干燥系统的分析及实际调试得出适用于微粉物料干燥的干燥系统的工作参数。     

高湿物料真空连续复合管束烘干设备研制初步探讨

从分析影响烘干设备干燥效果的烘干时间、加热温度、运行距离、物料与加热系统的接触面积入手，研制出高湿物料真空连续复合管束烘干设备。干燥主机采用三个不同直径的同心圆筒组成多级干燥室，各个干燥室内设有一定数量的加热管束，利用真空连续干燥、热能按需分配的原理，延长物料在干燥主机内的烘干时间、运行距离，加大物料与加热系统的接触面积，提高烘干设备的空间利用率。从而有效踺提高了烘干效率，降低烘干成本，改善了物料品质；改变了传统管束烘干设备采用一级干燥室的空间利用率低、热能不被充分利用的局面。     

适用于堆密度大的粉状物料的混合器

<正> 通常采用成批生产的带式和行星-螺旋式混合器对堆密度不大于1500千克/米~3散粒物料进行混匀加工。乌克兰化工机械制造科学研究所北顿涅茨克分所研制出一种新型混合器,它能对堆密度达2500～4800千克/米~3(颗粒大小为1～3.5微米)各种牌号粉状羰铁作混匀加工。由这类粉状物料的物理-     

内加热流化床在草甘膦干燥中的应用

针对草甘膦物料的干燥特点，分析对比了不同的干燥方法。设计了一套内加热流化床干燥系统，并进行了测试分析与对比。结果表明设计中采用的措施合理有效，设计参数可靠。新系统能显著提高热效率、降低动力消耗，明显改善产品质量。     

粉体干燥-造粒-微波加热干燥新工艺

从讨论粉体干燥、粉体造粒、颗粒干燥等技术特性出发，试图科学地建立一条新的粉体前期干燥一造粒一微波加热干燥工艺路线。先进行恒速阶段的物料干燥，使物料除湿，成为湿含量低于20％（湿基）的物料。低湿含量的物料用压力法造粒，此时不仅易于成粒，成粒率高，且颗粒粒度均匀，强度高，将这种颗粒物料用微波加热进行干燥，可以使颗粒内部的湿分迅速排除，从而获得合格湿分要求的产品。     

惰性粒子流化床干燥器的研究

本文在以内径为145mm、粒径为1．5mm的玻璃珠作为惰性粒子的流化床中对钛白粉浆料进行了干燥实验研究．实验结果表明，惰性粒子流化床能有效地对浆状物料进行脱水干燥，与其它几种浆状物料干燥器相比，具有容积传热系数大、热效率高、对物料适应性大等优点．实验发现浆料在情性粒子流化床内干燥，其过程可能表现为两种操作状态：’稳定操作和非稳定操作．在系统参数和操作条件给定时，干燥器存在一最大干燥能力．若加入的浆料速率超出其干燥能力而得不到及时的干燥脱水，湿料粘结在壁和玻璃珠的表面上，导致玻璃珠聚结成团，最终会形成死床…     

苯胺黑干燥袋滤器爆燃事故原因分析及处理预防措施

苯胺黑是染料和添加剂，其制作过程中干燥是反复必经步骤。在苯胺黑干燥时采用闪蒸干燥系统进行干燥，干燥后的物料细粉可随气流送至袋滤器收集。但收集过程中袋滤器多次发生事故，对人身安全与财产带来危害，因此对此事故原因，处理方法与预防措施进行了分析整理。     

中央物料输送系统

中央物料输送系统显然很复杂，对于习惯在机床边加料和进行原料干燥的人，它可能很吓人。但中央物料输送系统是可以学会的，你一旦学会，它就能发挥强大的功能。而且，这种设备不占生产车间的地面空间。     

旋转闪蒸干燥机系统参数的选择

简述了ＳＫＳＺ型旋转闪蒸干燥机的工作原理，并通过对国内数十家不同含湿物料的干燥工艺实践，归纳出三种干燥工艺系统的设备配置和相应的操作压力降分布状态，进而提出相应状态下对各种配套设备的选择，特别是对离心式通风机、管道、旋风分离器、袋式过滤器等参数选择原则。此外还列举了某厂对滤饼状物料选用ＳＫＳＺ１２５型旋转闪蒸干燥机系统进行干燥的应用情况。     

木薯酒糟临界含水量与干燥曲线

绘制了木薯酒糟薄层干燥过程曲线,对实验数据进行了拟合,并预测了一定条件下该物料的临界含水量,为设计适合该物料的干燥系统提供了基础数据     

Impact of agitated drying on the powder properties of an active pharmaceutical ingredient

In this study, the impact of agitated drying on the physical and bulk powder properties of an active pharmaceutical ingredient (API) is presented. The effects of different agitated drying conditions such as agitation rate, drying temperature, drying time pre-agitation, drying time during agitation and number of solvent wash cycles on the bulk density, millability, flow and specific surface area is reported. The crystal morphology is altered from fibrous needles to agglomerates when switching from tray to agitated drying. An increase in bulk density and specific surface area was evident when using agitated drying compared to tray drying as hard coarse granules were produced with an increase in the number of fine particles < 10 μm. The bulk density was found to increase with an increase in agitation speed, drying time and number of solvent wash cycles used during filtration. Controlling both fine and coarse particle size of the granules for this API during agitated drying was difficult to achieve due to the fibrous crystal habit. However, the increase in the bulk density observed has the potential to facilitate improvements in the ease of drug product development. In the case of this system further particle size control was required through the use of dry milling.     

EFFECT OF DRYING METHOD ON SHRINKAGE AND POROSITY

The effect of drying method on bulk density, particle density, specific volume and porosity of banana, apple, carrot and potato at various moisture contents was investigated, using a large set of experimental measurements. Samples were dehydrated with five different drying methods: conventional, vacuum, microwave, freeze and osmotic drying. A simple mathematical model was used In order to correlate the above properties with the material moisture content. Four parameters with physical meaning were incorporated in the model: the enclosed water density p_w, the dry solid density p_s, the dry solid bulk density p_bo and the volume shrinkage coefficient β'. The effect of drying method on the examined properties was taken into account through its effect on the corresponding parameters. Only, dry solid bulk density was dependent on both material and drying method. Freeze dried materials developed the highest porosity, whereas the lowest one was obtained using conventional air drying.     

SOME THEORETICAL AND EXPERIMENTAL CONSIDERATIONS ON THE THIN-LAYER DRYING OF FISH CRACKERS: PRODUCT EXPANSION ASSESSMENT

Fish crackers are semi-prepared starch-based products which must be expanded just prior to consumption. This work aims at the experimental and theoretical study of the thin-layer drying process of fish crackers in a thin disc geometry. The process was carried out in an insulated cabinet dryer and the experimental kinetic drying data were fitted using the analytical solutions resulting from both a drying model governed by the Fick' s second law and a model based on the lumped system, highlighting the adequacy of each of them. Therefore, it was possible to calculate the mass transfer coefficients for seven different blends offish crackers. Also, the effect of the drying time on the bulk density of the puffed product was evaluated for these seven blends. Both the kinetic drying parameters and the optimal bulk density responses were analyzed using the Simplex-Lattice Design over a mixture triangle within a minimal number of experiments.     

SOME THEORETICAL AND EXPERIMENTAL CONSIDERATIONS ON THE THIN-LAYER DRYING OF FISH CRACKERS: PRODUCT EXPANSION ASSESSMENT

ABSTRACT

Fish crackers are semi-prepared starch-based products which must be expanded just prior to consumption. This work aims at the experimental and theoretical study of the thin-layer drying process of fish crackers in a thin disc geometry. The process was carried out in an insulated cabinet dryer and the experimental kinetic drying data were fitted using the analytical solutions resulting from both a drying model governed by the Fick' s second law and a model based on the lumped system, highlighting the adequacy of each of them. Therefore, it was possible to calculate the mass transfer coefficients for seven different blends offish crackers. Also, the effect of the drying time on the bulk density of the puffed product was evaluated for these seven blends. Both the kinetic drying parameters and the optimal bulk density responses were analyzed using the Simplex-Lattice Design over a mixture triangle within a minimal number of experiments.     

EFFECT OF DRYING METHOD ON SHRINKAGE AND POROSITY

ABSTRACT

The effect of drying method on bulk density, particle density, specific volume and porosity of banana, apple, carrot and potato at various moisture contents was investigated, using a large set of experimental measurements. Samples were dehydrated with five different drying methods: conventional, vacuum, microwave, freeze and osmotic drying. A simple mathematical model was used In order to correlate the above properties with the material moisture content. Four parameters with physical meaning were incorporated in the model: the enclosed water density p_w, the dry solid density p_s, the dry solid bulk density p_bo and the volume shrinkage coefficient β'. The effect of drying method on the examined properties was taken into account through its effect on the corresponding parameters. Only, dry solid bulk density was dependent on both material and drying method. Freeze dried materials developed the highest porosity, whereas the lowest one was obtained using conventional air drying.     

A New Drying Approach to Enhance Quality of Konjac Glucomannan Extracted from Amorphophallus muelleri

A new drying approach to enhance physical quality of konjac glucomannan extracted from Amorphophallus muelleri was studied. It consisted of a comparison between microwave vacuum drying and conventional hot-air drying. The effects of microwave vacuum drying and hot-air drying on drying kinetics and physical and structural properties such as color, bulk density, particle density, porosity, viscosity, and morphology of konjac glucomannan (KGM) flour were investigated. It can be concluded that microwave vacuum drying significantly reduced drying time and increased porosity of dehydrated products which have a positive effect on the viscosity of the KGM solution. In contrast, it decreased bulk density and particle density when compared with conventional hot-air drying. Microstructure observations revealed the presence of large cavities in the granules of microwave-vacuum-dried KGM samples. However, there was a slight change in color of the microwave-vacuum-dried samples, resulting in a lower whiteness index than the whiteness index of hot-air-dried samples. Hence, microwave vacuum drying was found to have a number of advantages over the conventional hot-air drying method. Therefore, microwave vacuum drying has potential to become a useful drying method for the industrial production of KGM flour.     

HIGH HUMIDITY DRYING OF CORN: EFFECT ON DRYING RATE AND PRODUCT QUALITY

Drying of corn was studied at high and low humidity condiitions. Drying rate was measured, and test weight (bulk density), solid density, stress cracks, and breakage susceptibility of the dried grain at 15% (w.b.) were measured. Twenty four 350-g samples were dried under eight drying conditions in the 71° -104°C temperature range and 0.8%-80% RH relative humidity range. Each sample was exposed to the drying wnditions by using a semi-closed air flow cycle through a thin-layer of grain. High humidity drying reduced the drying rate by up to 44% and did not increase bulk density or solid density significantly as wmpared with low humidity drying. However, high humidity drying did reduce the multiple stress cracks in the corn kernels by up to 33.0 percentage points, increased the number of kernels with no stress cracks by up to 28.7 percentage points, and reduced Wisconsin and Stein breakage susceptibilities by up to 8.9 and 13.5 percentage poinu, respectively.     

Determination of porosity change from shrinkage curves during drying of food material

Based on a very simple model of mass conservation, three experimental properties (solid density, liquid density and initial bulk density) and the simultaneous acquisition of the reduced moisture content and the volume shrinkage during drying, a simple method is proposed to calculate the bulk porosity of a material during drying. This model allows a graphical interpretation to visualize the porosity change by comparing the experimental shrinkage curve with an ideal shrinkage curve. In the present work, several examples were taken from the literature to illustrate the application of this method to foodstuffs (apple, banana, carrot, garlic, pear, potato and sweet potato) with two different processes (convective drying, freeze-drying) and different drying conditions. Porosity calculations including error estimations showed a good agreement with experimental values reported in the literature.     

Spray Drying of Tomato Pulp: Effect of Feed Concentration

The effect of feed concentration on spray drying of tomato pulp preconcentrated to 78, 82, and 86% wet basis is investigated in two spray drying systems: a pilot scale spray dryer (Buchi, B-191) with cocurrent regime and a two-fluid nozzle atomizer, and the same connected with an absorption air dryer (Ultrapac 2000). Data for the residue on the chamber and cyclone walls were gathered and two types of efficiencies were calculated as an indication of the spray dryer performance. Tomato powders were analyzed for moisture, particle size, and bulk density. In both spray drying systems, with increases in tomato pulp concentration overall thermal efficiency, evaporative efficiency, material loss in the cyclone, powder moisture content, and bulk density decreased, whereas powder particle size increased. On the contrary, the effect of feed solids content on residue formation and product recovery was dependent on the drying medium. In the standard dryer, the higher the feed concentration, the higher was the residue accumulation, and the lower the product recovery, whereas in the modified system increases in pulp concentration resulted in lower residue formations and higher product yields.     

应用超临界流体干燥技术制备气凝胶的研究进展

超临界流体干燥技术广泛应用于气凝胶的制备中，是制备具有高比表面积、低堆积密度及大孔体积气凝胶的重要途径之一。综述了超临界流体干燥技术原理、历史背景及其研究现状，并对超临界流体干燥技术中的工艺条件进行了简要评述。