高塔熔体复合肥造粒温度在料浆三相点附近的优点

针对高塔造粒生产复合肥存在塔壁结疤、产品结块的问题,开发了高塔熔体复合肥在造粒料浆三相点温度附近造粒的技术,阐述造粒料浆三相点温度的确定方法,以及在三相点附近造粒之优点。由于该造粒技术可使造粒温度比原来降低15℃左右,有效地防止了复合肥产品结块,降低了生产成本。     

影响尿基复合(混)肥造粒的主要因素分析

针对转鼓喷浆造粒工艺生产尿基复合(混)肥所存在的问题,分析造粒温度、湿度、时间,物料的溶解度、黏度、粒度、均匀程度,料浆雾化程度,返料状况,以及造粒设备、干燥方式等影响造粒的主要因素;提出控制造粒温度与湿度的方法,为生产尿基复合(混)肥工艺参数的优化提供了可借鉴的思路.     

导热油进口速度对造粒模板造粒带温度均匀性影响

造粒模板是切粒系统的主要部位之一，造粒模板内部包括加热通道与物料通道，通道内部流动介质分别为导热油和聚乙烯。探究在同等条件下，导热油进口速度分别为0.01、0.05、0.1 m/s的情况下物料挤出速度与造粒带温度分布的均匀性。应用SolidWorks软件对造粒模板进行三维建模，采用ANSYS软件对聚合物与导热油的流动与传热进行数值模拟，获得了造粒模板的温度分布与流体流场分布。结果表明，导热油的进口速度对造粒模板温度场的影响明显，导热油进口速度在0.01、0.05、0.1 m/s 3个条件下，物料的挤出速度变化不大，造粒带的温差分别为14.08、7.14和5.39 ℃。在导热油进口速度为0.1 m/s时，造粒带温度分布最均匀。     

浮法玻璃配合料粒化的研究

通过粒化实验确定了具有较好粒化性能的工艺参数,通过高温熔制实验得出熔化粒化后的配合料可以达到节能的目的.     

牛初乳粉低温造粒的实验研究

为考察料液流量、料液浓度和料液种类等影响牛初乳颗粒生长速率的因素,得到牛初乳颗粒的生长规律及工艺参数,为流态化低温造粒装置的研制提供依据,以牛初乳粉为原料,采用低温流态化喷雾造粒技术制取了牛初乳颗粒。结果表明,低温造粒能够保护产品质量不变,保持物质原有的色、香、味及营养。     

影响磷酸二铵造粒的因素

讨论中和度、料浆密度、二次补氨、造粒温度、造粒时间、返料等工艺指标对磷铵造粒的影响程度与状况,以期获得外观好、养分合格(主要指氮)的磷酸二铵产品。     

Cooling and Solidification of Melted Drops in an Immiscible Cooling Medium

The cooling and solidification of melted drops during their movement in an immiscible cooling medium is widely employed for granulation in the chemical industry, and a study of these processes to provides a basis for the design of the granulation tower height and the temperature of the cooling medium is reported. A physical model of the cooling and solidification of the drop is established and the numerical calculation is performed. The influences of the key factors in the solidification, i.e., Bi number, drop diameter, temperature of the cooling medium, etc. are presented. The cooling and solidification during wax granulation in a water‐cooling tower and during urea granulation in an air‐cooling tower (spraying tower) are described in detail. Characteristics of the solidification and temperature distribution within the particle at different times are shown. The model and calculations can be used for structure design of the granulation tower and optimization of the operation parameters.     

流化床喷雾造粒过程的传热传质

This article presents a mathematical model of heat and mass transfer for the process of fluidized-bed spray granulation, which can be applied in the analysis of bed temperature profile, temperature and humidity of outlet gas and moisture content of particles. Effects of operation parameters on the batch granulation are investigated. The theoretical calculation agrees reasonably well with the experimental data.Keywords fluidized-bed spray granulation, mathematical model, heat and mass transfer     

Granulation time in fluidized bed granulators

Size enlargement of particles in fluidized bed granulation involves mixing of particles with a binder liquid to form larger wet granules and drying them to form dry granules. Identification of the time for completion of granulation process is critical as further fluidization of dry granules is providing extra energy for their attrition. Monitoring the bed pressure drop and bed temperature of a batch fluidized bed granulator with time can provide information on the time for completion of the granulation process. Experimental observations on granulation time and size of granules in a lab-scale batch fluidized bed granulator are presented. Model based equations are developed for the estimation of granulation time and size of granules.     

转鼓流化床熔体造粒生产硝基复合肥造粒技术的分析与探讨

采用转鼓流化床熔体造粒技术生产硝基复合肥时,造粒过程不仅受喷嘴的影响,还受混合料浆的特性、喷浆压力、造粒温度、返料比等因素的影响.另外,生产硝酸铵磷和硝酸铵钙时也有所不同,生产硝酸铵磷的料浆是用熔融硝酸铵与一定比例的粉状磷酸一铵进行搅拌混合而成,而生产硝酸铵钙是用熔融硝酸铵与一定比例的178 ～ 150 μm（80～100目）白云石粉搅拌混合而成.生产中,硝酸铵磷造粒温度宜控制在110～ 115℃,硝酸铵钙造粒温度可控制在100～105℃.     

用界限含水率指导复混肥的生产

引入土工学中的界限含水率,将其测定方法改进后测定一定温度下复混肥原料混合物的液限和塑限,考察其与复混肥生产的关系。结果表明:合适的塑性指数范围是衡量一个物系是否能良好成粒的一个重要参考依据。特别是塑限的测定和改变,对低水分造粒的研究有很大的帮助,有助于减少造粒水分,降低能耗,指导团粒法复混肥的生产。     

再生远红外丙纶生产工艺探讨

以远红外聚丙烯废料为原料 ,在普通涤纶纺丝设备上纺制再生远红外丙纶短纤维 ,并对造粒、干燥、纺丝成形、拉伸等工艺进行了探讨。远红外聚丙烯经过再造粒后 ,其熔体流动指数较原料高出 10左右 ,干燥温度一般控制 10 0～ 12 0℃ ,干燥时间 4～ 8h ,纺丝温度设定高于熔点 10 0℃左右 ,拉伸倍数 2～ 3较适宜     

如何提高高浓度复合肥的成球率

根据多年经验,从设备性能、原料特性、操作控制(如物料细度、均化、造粒水分与温度、干燥温度与风量等)等方面论述对提高复合肥造粒成球率的影响;说明造粒机出口物料出现小粒多(>15%)、大粒多(>15%)、大小粒均多、干燥机内物料产生粉化等不正常现象的原因及处理方法。     

Experimental study of the thermal granulation process in a spouted bed

Experimental study is made of the granulation of fine dispersed materials in spouted beds. According to the first method, the granulation is carried out by blowing the gas-dust flow through the bed of coarse particles, whose surface is melted by a high-temperature fluidizing gas. According to the second method, the granulation occurs in the spouted bed of fine particles, a part of which has a melting temperature lower than the fluidizing gas. The effect of spouted bed parameters on granulation kinetics is studied. Correlations are obtained for calculation of a mean final diameter of granulated particles. A granule size distribution is shown to be close to the normal one.     

大颗粒尿素造粒工艺简述

大颗粒尿素具有硬度高、肥效好、用途广等特点。目前,其造粒技术主要有流化床造粒、喷射流化床造粒、转鼓流化床造粒及高温盘式造粒等技术,简要介绍了上述几种造粒技术的工艺流程,评述了其各自的特点,指出发展大颗粒尿素造粒技术将是未来国内外尿素市场的发展方向。     

氯乙烯本体预聚合动力学和成粒过程的研究

对氯乙烯(VC)本体预聚合动力学和成粒过程进行了研究。通过称重法测定了VC预聚合阶段的转化率,同时研究了搅拌转速、聚合温度和引发剂用量对聚合动力学的影响。采用LS-230Coulter激光粒度仪测定聚合过程PVC粒子的体均粒径及其分布,考察了搅拌转速、聚合温度和引发剂用量对临界转化率和临界粒径的影响。根据实验结果并结合低转化率下VC本体聚合的微观成粒机理,提出了VC本体预聚合的成粒过程。     

Heat assisted twin screw dry granulation

A new “assisted” dry granulation method has been devised for the twin‐screw granulator. The method may be beneficial to drug preparation as it limits heat exposure to only one barrel zone, much shorter than melt granulation. Its mechanism was investigated using four placebo formulations, each containing a polymer binder with a glass transition temperature lower than 130°C. Variables of study included screw configuration, screw speed, barrel zone temperature, and moisture content. Granulated samples were characterized for size and porosity while feed powders were examined for their thermal transitions, interparticle friction, cohesion, and sintering rate. Results indicated that granule coalescence relied on melting of polymer binder in the kneading blocks by a combination of heat conducted from barrel and generated from screw speed friction. Successful granulation was possible with minimal addition of water, although varying the moisture content showed the relevance of the polymer's glass transition temperature and sintering progress. © 2017 American Institute of Chemical Engineers AIChE J, 2017     

无需干燥的团粒法复混肥料生产工艺研究

在原有团粒法复混肥料生产工艺技术中省去干燥单元,能降低能耗并减少环境污染.实施无干燥工艺生产高浓度复混肥时,要求造粒机出口物料含水质量分数在0.8%～1.5%,造粒物料的温度在75～85℃.比较实用和经济的手段是直接利用尿素装置的高温浓缩尿液,然后再酌情将部分原料预热至一定温度.实施无干燥工艺后,返料量比传统团粒法工艺...     

强化好氧颗粒污泥稳定性的研究进展

系统回顾了有关好氧颗粒污泥稳定性方面的研究进展,简要介绍了好氧颗粒污泥的形成机理,主要包括“丝状菌假说”、“胞外聚合物假说”、“选择压驱动假说”、“自凝聚假说”;着重分析了影响好氧颗粒污泥稳定性的主要因素有温度、pH值、有机负荷率与氨氮浓度、溶解氧与颗粒粒径、饱食-饥饿期、水力剪切力、污泥龄和有毒有害物质等;详细论述了抑制丝状膨胀、促进胞外聚合物的分泌、富集慢速增长的微生物和强化颗粒内核等措施可以强化好氧颗粒污泥的稳定性,并提出了对好氧颗粒污泥的形成机理以及功能菌群进行更深入的研究将会是今后的研究重点,进而为好氧颗粒污泥的工业化应用作铺垫。     

用磷石膏处理麦饭石配制复混肥增效调理填充料

介绍磷石膏处理麦饭石配制复混肥增效调理填充料。磷石膏与麦饭石以1：1（质量比）掺混,常温下堆闷3～5d,制成水分含量适中的造粒填充料配入复混肥中,可灵活调整复混肥料的总养分。通过5—6年大田试验表明,加入该增效调理填充料的复混肥有明显的增产作用。