盘式干燥器在硫酸钾生产中的应用

本文介绍了盘式干燥器的特点、设备结构、干燥机理及在硫酸钾生产中的应用情况与经济效益分析。     

盘式干燥器在硫酸钾生产中的应用

本文介绍了盘式干燥器的特点、设备结构、干燥机理及在硫酸钾生产中的应用情况与经济效益分析。     

盘式干燥器加热盘的设计

文章通过对盘式干燥器主要承压部件──加热盘的受力分析，建立了加热盘上、下板的力学模型，并推出了板的挠曲线方程式和应力计算公式，由此得到了板厚度的计算方法。     

干燥设备在甘露醇生产中的应用

主要阐述微波干燥器与沸腾流化床干燥器两种设备的原理和特点,分别就它们在甘露醇生产中的干燥效果、灭菌效果和动力消耗等方面进行了比较。     

国外的食品干燥设备

干燥既是一种主要的食品保存方法,也是许多种食品的一种重要加工技术。目前,国外生产的食品干燥设备主要有四类:传送带式干燥器,喷雾干燥器,鼓轮式干燥器和真空干燥器。这些基本型式的干燥器常用于固体、半固体和流体食品的脱水。对干燥设备的要求是:     

正弦曲线气浮干燥器与气翼干燥器简介

１涂布机常用干燥器型式涂布机所采用的干燥型式,以热风干燥居多;有的采用热风干燥辅之以红外加热。热风干燥器按结构形式可分为两种：一种是涂布纸在干燥器中受到导辊承托的直喷式热风干燥器;另一种是无导辊承托的平衡干燥器。而平衡式干燥器又分为互平衡式干燥器（正...     

ROSIN环形干燥器

在ROSIN工程公司制造的众多干燥器(流化床干燥气流干燥器、环形干燥器、ROSINARIE浆式干燥器、旋转干燥器、塔式子燥器)中,环形干燥器具有热效率高,投资成本低,设计布置灵活,低的高度需要和垂直自身支撑等特点。可广泛应用于化学、制药、食品等工业领域,如食品工业中的淀粉,小麦面筋,黄原胶等产品的干燥。环形干燥器是一种气流干燥器,它可以控制干燥时间、干燥温度、物料流动。干燥管是一个两端连接的环,湿物料在其中循环直至干燥,干空气不断更新。要被干燥的物料可以在一个较广泛范围内自由选择的条件下随气体运动。热敏性物料在低温下干燥,同时,在需要时也可在高温下应用。ROSIN环形干燥器的处理量范围从每小时蒸发50kg水至十几吨水。干燥介质可以是空气、燃烧产品、或在蒸发溶剂     

涂布纸的新干燥法

一般采用３种方法干燥涂布纸：红外线辐射（IR）干燥、气浮式干燥及烘缸干燥。涂布机干燥部通常组合了这些元件。由于需要节能和减少投资费用，因而影响了涂布机干燥部的发展。目前的趋势是朝着高效、易于维护的简单干燥器和干燥布置的方向发展。因此，在一些质量问题已经解决的刮刀涂布机中采用了OptiSizer中简单的空气干燥器布置。本文讨论了涂布纸干燥的发展情况并介绍了干燥是如何影响纸页质量的一些新的结果（见图１）。１IR干燥器近１０年来，在涂布干燥领域，气体红外线干燥器已代替电气红外线干燥器。但气体IR干燥器的缺点是节…     

影响空气干燥器干燥效果的分析

压缩空气是发电厂重要的公用系统。在使用过程中,常会导致干燥效果恶化。文章假设干燥器的每个循环周期内都再生塔均能完全再生,通过分析压缩空气运行中可能变化的参数(空压机入口空气湿度、干燥器进口温度、干燥器工作压力、干燥器再生流量、干燥器再生压力)对干燥效果的影响,判断运行过程中露点升高的原因,及解决方法。     

黄原胶生产中的盘式连续干燥器

本文分析了食品添加剂——黄原胶生产中连续干燥器的技术特性和应用情况,通过试验证实该干燥器具有热效率高、不污染环境等优点。     

用颗粒热传递模型计算旋转管排式干燥机的传热系数

论述了应用基于移动加热板的颗粒热传递模型计算大型旋转管排式干燥机传热系数的方法。在料床完全混合的简化假设下,按物料在干燥机内的实际干燥过程,分35段计算各段的传热系数及整机总传热系数,所得结果与干燥机的实际运行情况基本相符。     

造纸机的新型多通道烘缸

目前的造纸机烘缸大多采用虹吸管式冷凝水排出装置,由于受烘缸积水的影响,导致传统烘缸的干燥效率下降,纸页受热不均匀。基于此,介绍了对该传统结构进行改进的方法,采用多通道式冷凝排水装置,并将2种烘缸在干燥机理、传热效率和干燥设备的技术性能指标等方面进行了详细的比较,得出了多通道式烘缸干燥效率高。能耗小等优点。     

核桃热泵穿流干燥特性

为研究核桃深层装载形式下的热泵穿流干燥特性,探讨干燥温度对不同装载深度层核桃含水率及干燥速率的影响。本文以陕西省"香玲"核桃为实验原料,研究风速恒定条件下,装载深度为0.3、0.6、0.9 m时,各装载深度核桃在35、45、55 ℃干燥温度下的含水率、干燥速率、干燥均匀性。综合干燥均匀度、能耗及干燥温度对核桃品质的影响,确定热泵穿流干燥最佳干燥工艺参数为:干燥温度45 ℃,风速1 m/s,装载深度0.9 m。采用最佳干燥工艺参数,对比分析热泵穿流干燥设备与盘式烘干设备的干燥性能,表明热泵穿流干燥设备在能耗、干燥效率、干燥容积利用率等方面均优于HG-400型盘式核桃烘干机,单位耗电量是HG-400型盘式烘干设备的40%,装卸料耗时缩短1.9 h,且装卸料耗时是HG-400型盘式烘干设备的20%。     

DETERMINATION of HEAT TRANSFER COEFFICIENTS DURING DRYING of FOODSTUFFS

Heat transfer coefficients during drying of foods were evaluated from drying data and heat and mass balances. Experimental drying curves for slices and cylinders of potato, apple and carrot were obtained in a laboratory dryer under different drying conditions. the specific heat of the foodstuffs was measured as a function of water content and modelled through a linear relationship. Experimental heat transfer coefficients were correlated by the dimensionless expression Nu_D= 0.249 Re_D^0.64 and compared with predictions of different equations.     

DRYING of COFFEE BERRIES IN A VIBRATED TRAY DRYER OPERATED WITH SOLIDS RECYCLE and SINGLE‐STAGE1

A vibrated tray dryer was tested for drying coffee berries. It consists of a vertical chamber (0.33 m × 0.18 m × 1.30 m) provided with four trays. the trays are supported by a vibrated shaft. Experimental tests were carried out at a vibration amplitude of 1 mm and at a variable frequency. the process itself consisted of feeding the vibrated tray dryer with an initial mass of coffee berries: after leaving the dryer through the discharge channel, the berries were fed again to the top of the dryer by a bucket elevator (intermittent operation with recycle of the coffee berries). Drying tests were carried out with drying air velocity of 2.4 m/s. the drying air control temperature was related with the temperature of the coffee berries at the discharge (under 45C). the drying time required for coffee berries to reach 12.6% (wb) moisture was 28 h, initial mass (moisture of 67% wb) was 5.54 kg. In this work the influence of vibration in single‐stage drying is also shown. the single‐stage operation shows that vibration (besides promoting the conveyance of coffee berries) also reduces the time of drying.     

Fluidized bed and tray drying of thinly sliced mango (Mangifera indica) pretreated with ascorbic and citric acid

The purpose of this work was to determine the influence of air temperature, sample diameter and antioxidants on water activity, moisture content and colour difference of thinly sliced mango in a fluidized bed and tray dryer. Mango samples were treated with antioxidants solutions (ascorbic and citric acid) before the drying process. Fluidized bed and tray drying of control and treated samples were carried out at two temperatures: 50 and 60 °C. A fractional factorial design 2^4?1 was used in both drying methods. The Newton semi‐theoretical model was found to represent thin‐layer drying kinetics of mango. For both drying types, moisture content of thinly sliced mango was well characterised (R² ≥ 0.975) by the model. The temperature increment increases the drying constant and decreases the equilibrium moisture content and water activity of the dehydrated samples. Colour closest to the original colour of fresh mango was obtained when 2 cm diameter mango pretreated with citric acid (1%) was dehydrated by fluidized bed at 60 °C. In addition, it was observed that the drying time at equilibrium by using fluidized bed was lower (60 min) than the tray dryer (120 min).     

滚筒干燥数学模拟的研究进展

滚筒干燥机因其操作简便、适应性广、热效率高、干燥时间短而被广泛应用于食品工业中.以经验为基础的滚筒干燥工艺不能满足生产需要.建立滚筒干燥过程的数学模型有助于优化工艺参数、提高产品质量、改进滚筒干燥机设计.本文对滚筒干燥原理及其传热传质机理进行了概述,重点介绍了滚筒干燥过程数学模拟的研究进展,并通过对文献的分析总结,对数...     

扰流棒在提高热传导性能和冷凝水排出过程中的作用

扰流棒位于纸机烘缸内部,用来提高热传导,提高干燥均匀度.当扰流棒配置正确,冷凝水达到最佳深度时,采用扰流棒不仅能提高传热速度,还能取得良好的干燥均匀度.本文主要介绍在JOCO 4000试验烘缸内安装扰流棒,从而得出达到最佳性能需要考虑的各种因素.     

Studies on the effects of microwave drying and cabinet tray drying on the chemical composition of volatile oils of garlic powders

Garlic cloves in the form of bits were dried in a cabinet tray dryer and a microwave dryer, and pulverized to obtain free flowing powder. The volatile oil was obtained by hydro-steam distillation method. Fresh cloves and the powders resulting from the two drying methods were used for obtaining the volatile oil, which was analyzed by GC-MS. The studies were mainly restricted to comparing the effect of drying methods on the volatile oil composition of the powders. Although the drying time was reduced considerably from 8 h in a cabinet dryer to 0.25 h in a microwave dryer, essential oil yield and color values were lower, and flavor quality varied considerably. The relative concentrations of major peaks such as diallyl disulfide, diallyl tetrasulfide increased in both the drying methods, and it was more so in microwave-dried samples. However, the concentrations of the other two major peaks, diallyl trisulfide and allyl methyl trisulfide, decreased in both drying methods, and they were lower in microwave-dried samples. Hunter values of L and b were lower for samples obtained by microwave drying as compared to those of cabinet-dried samples.     

Beseitigung von Geruchsbelästigungen,verursacht durch Trockner in der Maisstärkeindustrie

Elimination of Odors caused by Dryers in the Corn Starch Industry . The rotary tube dryer is suited for drying pressed hulls. The vapors emitted by the dryer are odorless. Subsequent mixing with steepwater depends essentially on the absorption power of the material. This is best when the hulls, upon leaving the first dryer, still show sufficient moisture and when the inlet moisture at the second dryer — adjusted by dry material recycling — is kept below 35% H₂O. The vapors produced when drying the hulls mixed with steepwater emit a distinct odor which can be eliminated by burning the vapors at temperatures above 800 °C, for instance in the furnace of a boiler. The decrease in efficiency during steam generation accounts for about 0.5 to 0.8%. To avoid that the temperature in the boiler falls below the dew point, it is recommended to heat the vapors emitted by the dryer on their way to the boiler furnace. A steam-heated heat exchanger should be used if washing of the vapors was necessary as otherwise the heating system will be encrusted quickly.