Relating the Stickiness Property of Foods Undergoing Drying and Dried Products to their Surface Energetics

Stickiness is a common problem encountered in food handling and processing, and also during consumption. Stickiness is observed as adhesion of the food to processing equipment surfaces or cohesion within the food particulate or mass. An important operation where this undesirable behavior of food is manifested is drying. This occurs particularly during drying of high-sugar and high-fat foods. To date, the stickiness of foods during drying or dried powder has been investigated in relation to their viscous and glass transition properties. The importance of contact surface energy of the equipment has been ignored in many analyses, despite the fact that some drying operations have reported using low-energy contact surfaces in drying equipment to avoid the problems caused by stickiness. This review discusses the fundamentals of adhesion and cohesion mechanisms and relates these phenomena to drying and dried products.     

Problems Associated With Spray Drying Of Sugar-Rich Foods

ABSTRACT

Stickiness is a major reason that limits the spray drying of various sugar-rich food products.Higher hygrmopicity of amorphous powder, increase in solubility of sugars with temperature, and lower melting point and glass transition temperature, contribute to the aickiness problem. So far, the glass transition temperature has been widely accepted as a ben indicator for stickiness. There are various manawm that have been applied to spray dry such product. Some of them are the addition of drying aids, modilication of drier design and use of mild drying temperature conditions. This review paper highlights the major research works that deal with the stickiness property of sugar-rich foods.     

Measurement of Glass–Rubber Transition Temperature of Skim Milk Powder by Static Mechanical Test

Abstract

Stickiness behavior of skim milk powder was investigated based on the mechanical property of the material during the glass–rubber transition. A thermally controlled device was developed for the static mechanical test. This device was attached to a texture analyzer, and skim milk powder, which was used as a model sample, was tested for its glass–rubber transition temperature (T_g-r) using static compression technique (creep test). Changes in compression probe distance as a function of temperature were recorded. T_g-r was determined, in the region where changes in the probe distance were observed, by using linear regression technique. The effect of sample quantity, compression force, and heating rate on the determination of T_g-r was investigated. All these parameters significantly influenced the T_g-r determination (p < 0.05). The T_g-r of skim milk powder measured by this novel technique was found closely correlated to its glass transition temperature (T_g) measured by DSC.     

聚氨酯涂料中粉料的分布特征与漆膜发白行为

固体粉料在漆基中的润湿与分散是涂料制造的重要过程，直接关系到漆膜的各项性能。为了揭示粉料在聚氨酯涂料中的分布特征及其对漆膜抗发白行为的影响规律，本文研究了粉料在润湿与分散过程中的微观物理形态、以及粉料在漆膜表层与不同厚度处的分布特征，分析了粉料用量及其分散均匀性对漆膜发白现象的影响，初步探讨了粉料影响漆膜发白行为的内在机理。     

水泥磨前掺加粗矿粉的实践应用

粒化高炉矿渣粉是水泥生产中的重要活性混合材料,矿粉活性的高低直接影响水泥产品质量。生产过程中存在磨机开停或检修后磨合阶段,此阶段所生产的矿粉存在细度偏粗、比表面积低、早期活性偏低等问题。针对此问题,我公司将该部分矿粉通过水泥磨头物料仓微机计量入磨与熟料、石膏和其它辅助混合材共同粉磨,达到稳定水泥质量,实现最终消化的目的。     

聚丙烯酰胺粉末降尘技术研究

介绍了一种聚丙烯酰胺粉末降尘技术。通过室内评定、工业化降尘应用试验和现场配注应用试验证明,该涂层剂具有很好的降低聚丙烯酰胺粉末扬尘效果。室内对照实验表明涂层后聚丙烯酰胺的抗剪切能力、耐盐能力和热稳定性均有一定程度的提高,说明涂层后的聚丙烯酰胺更适用于三次采油领域。涂层操作简便易行,利用聚丙烯酰胺生产现有工艺设备就可进行工业化生产。采用本降尘技术可在聚丙烯酰胺正常生产中和处理库存细粉中创巨大的经济效益和社会效益,同时,大大改善了生产装置和现场配制的粉尘问题,给生产和应用操作人员创造了更好的工作环境。     

聚乙烯蜡超细粉的生产工艺和应用

对物料进行超细化处理 ,使其物理化学性能发生许多特殊的变化 ,这一高新技术正日益受到重视 ,有着广阔的应用前景。通过对聚乙烯蜡超细粉生产工艺的比较 ,确定冷冻喷雾粉化生产工艺是最好的。利用现有的氧化聚乙烯装置 ,建成 30 0t/a聚乙烯蜡超细粉生产装置。介绍了此产品的生产工艺过程 ,以及其作为添加剂使油墨和涂料的性能得到提高 ,用途更加广泛     

我国粉末涂料市场现状及发展趋势

1 990～ 2 0 0 2年我国粉末涂料产量年均增长率为 2 4 % ,2 0 0 2年产量为 1 6万t,居世界前列。介绍了我国粉末涂料的生产现状及其在相关行业的应用 ,分析了粉末涂料制造技术与涂装技术今后的发展趋势。指出了粉末涂料行业产品结构调整方向及应重点开发的新品种     

Nonisothermal Synthesis of Yttria-Stabilized Zirconia Nanopowder through Oxalate Processing: I, Characteristics of Y-Zr Oxalate Synthesis and Its Decomposition

To obtain powder with a composition of 3 mol% Y₂O₃–97 mol% ZrO₂, a process of Y-Zr oxalate powder production has been optimized, to produce an oxalate with minimal particle size. The methodology of the nonisothermal decomposition of Y-Zr oxalate has been explained. Characteristics of the nonisothermal decomposition of different oxalates have been studied. Nanocrystalline Y₂O₃-stabilized ZrO₂ (YSZ) powder with a narrow size distribution of primary particles and aggregates was produced. The zirconia powder that was obtained from the smallest oxalate powder via nonisothermal decomposition had a particle size of 8–10 nm. The YSZ powder was weakly aggregated, with a narrow aggregate-size distribution of 70–90 nm.     

工业氧化铝在电瓷配方中的应用研究

随着国家对煅烧铝矾土加工行业生产管理的逐渐规范化,部分环保要求不达标煅烧矾土粉加工企业停产或在整顿改造中,导致煅烧铝矾土粉加工企业生产量下降,品质不达标,行业供货紧张。而煅烧铝矾土为电瓷生产行业使用的主要原料,在铝矾土粉供货紧张的局势下,为保证生产能正常进行,特进行工业氧化铝在湿法电瓷配方中的应用研究试验。     

Effect of bed material,lignin content,and origin on the processability of biomass in fast pyrolysis reactors

Lignin has great potential for the production of valuable aromatic compounds and has attracted considerable attention. The development of high value applications for Kraft lignin would boost the profitability of pulp and paper operations. A potential solution is the pyrolytic conversion of lignin to valuable liquids and solids. However, Kraft lignin is a thermally sensitive powder which tends to agglomerate under pyrolysis conditions. A mechanically fluidized reactor (MFR) can be used to monitor both the generation of vapours and gas during pyrolysis and how cohesive a feedstock becomes when pyrolyzed. The MFR was, therefore, used to evaluate alternative solutions to improve Kraft lignin behaviour by mixing it with non‐problematic feedstocks or by modifying its bed material. Finally, Kraft lignin behaviour and products were compared to those of hydrolysis lignins from different origins.     

Atomization of metal and alloy powders: Processes,parameters, and properties

Additive manufacturing (AM) has been intensively studied over this decade due to the increasing demand of functional and precise materials in various industries. AM process leverages on the concept of layer by layer deposition or joining of a material at micro- or nano-scale to produce the final products. As such, AM technology is widely used to manufacture products of complex geometries with high precision in a short time. As the quality and the performance of AM manufactured functional products depend on the quality and the cost of the atomized metal or alloy powder used, the use of powders of high size uniformity, high purity, high sphericity, high flowability, low cost, and no trapped gas bubble porosity is necessary. To this end, various metal production technologies were investigated and one of the popular technologies is atomization. This article reviewed the working principles of the various atomization technologies for the production of fine metal and alloy powders. The key atomization conditions discussed in this article include atomization type, material feed rate and temperature, atomizing fluid flow rate, type and temperature, cooling rate, and atomization pressure. In addition, several outlooks on the prospect and the optimization of atomization technologies were also discussed in this article.     

Si_3N_4粉连续生产用氮化炉

Ｓｉ３Ｎ４粉连续生产用氮化炉，可在高温下连续生产Ｓｉ３Ｎ４粉，避免了间歇生产中因装料、升温、降温、出料时造成的能源、时间的浪费，提高了生产效率，节约了能源；同时它还适宜采用二次氮化工艺，促进氮化反应。缩短了硅粉氮化生产周期，提高了产品的质量     

高温烧结刚玉SG抛光微粉的研制

本文关键在于突破磨料具行业传统的刚玉微粉制造工艺，作者采用了将氧化铝粉高温烧结，利用沉降法制取ＳＧ微粉有关工艺方法，并最终取得预期的理想效果，研制的微粉具有单特度高，自锐性好，磨削抛光效率高，研磨抛光效果明显优于棕刚玉微粉，完全可以达到白刚玉微粉的性能。     

Experimental Results Contributed to Early Detection of Smouldering Milk Powder as an Integrated Part of Maintaining Spray Drying Plant Safety

Smoldering milk powder lumps deposited on dryer walls or falling through the hot air could potentially start a fire or even an explosion in milk powder dryers. Explosive behavior is more frequently experienced in the modern industry, where high production throughputs are desired. It has been known that powder at such a state emits carbon monoxide (CO). The work reported in this article is the study of the characteristics of CO generation during the incomplete combustion of milk powders. The powders used in the study were whole milk and skim milk. Samples placed in a reactor were heated using air at 300°C. The exhaust air of the reactor was continuously measured for CO concentration using a highly sensitive CO analyzer. Temperatures were monitored, and the smoke produced during the combustion of whole milk powder was collected and analyzed using gas-chromatography mass-spectroscopy (GC-MS). Whole milk powder was found to produce significantly higher amounts of CO than skim milk powder. Hydrocarbons, alcohols, and carboxylic acids were tentatively identified during the GC-MS analyses. Results from the study are definitely useful in optimizing the use of an early fire detection system in milk powder plants.     

Experimental Results Contributed to Early Detection of Smouldering Milk Powder as an Integrated Part of Maintaining Spray Drying Plant Safety

Smoldering milk powder lumps deposited on dryer walls or falling through the hot air could potentially start a fire or even an explosion in milk powder dryers. Explosive behavior is more frequently experienced in the modern industry, where high production throughputs are desired. It has been known that powder at such a state emits carbon monoxide (CO). The work reported in this article is the study of the characteristics of CO generation during the incomplete combustion of milk powders. The powders used in the study were whole milk and skim milk. Samples placed in a reactor were heated using air at 300°C. The exhaust air of the reactor was continuously measured for CO concentration using a highly sensitive CO analyzer. Temperatures were monitored, and the smoke produced during the combustion of whole milk powder was collected and analyzed using gas-chromatography mass-spectroscopy (GC-MS). Whole milk powder was found to produce significantly higher amounts of CO than skim milk powder. Hydrocarbons, alcohols, and carboxylic acids were tentatively identified during the GC-MS analyses. Results from the study are definitely useful in optimizing the use of an early fire detection system in milk powder plants.     

优质水煤浆的研发与燃烧设备的技术改造

渗花抛光砖粉料、微粉抛光砖的面料生产一般使用重油或是煤气。成本比较高，笔者通过对水煤浆的理化性能作为研发重点。使之适合作为渗花抛光砖粉料、微粉抛光砖的面料的燃料。从而代替重油或煤气。降低生产成本。为了做到清洁生产．优化了水煤浆的配方．使用合适的添加剂，使用全酚水制浆．并按一定的比例添加煤气站的副产品——煤粉．从而降低生产成本．并对水煤浆的燃烧设备进行了技术改造．改善了除尘器除尘效果不佳的状况．取得了很好的效果。     

SCC-1型高效复合黏结剂在型焦生产中的应用

为了解决焦粉的再利用问题,提高能源利用效率,缓解焦粉露天堆放造成的粉尘污染,采用无机矿物质和有机高分子化合物复配制得SCC-1型复合黏结剂用于焦粉成型生产型焦。研究了焦粉的成型工艺,对工艺路线和工艺参数进行了选择和优化。用SEM分析了型焦的成型机理,并对型焦的性能进行研究。结果表明：采用SCC-1型复合黏结剂制备型焦,具有成型工艺简单,黏结剂用量少,不需要烘干工序,设备投资少,生产成本低等优点,大部分焦粉颗粒被SCC-1型复合黏结剂润湿后通过“黏结剂固体桥”连接而成型,制得型焦的冷压强度、落下强度、耐水性、热稳定性、反应活性等性能指标均满足工业生产工艺要求,具有很高的推广应用前景。     

Spherical particles for automotive powder coatings

Clear powder coatings that consist of spherical particles with a narrow particle size distribution were produced via a suspension method that involves the agglomeration and unification of smaller particles. These powder coatings have the advantages of excellent powder flowability and high transfer efficiency. This behavior is attributable to the spherical particle shape and absence of finer particles. This production method has been developed for thinner film build clear coats with improved surface smoothness as compared to powder coatings produced by conventional methods.     

两段竖式石墨化炉的设计及其生产实践

人造石墨粉当前在国内国际市场供不应求，如何用新工艺、新设备生产高质量的人造石墨粉是急需探讨研究的新课题。本文着重就这一课题阐述通过市场调研、科学实验、设计调研等阶段完成两段竖式石墨化电炉的实践过程。