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。     

流化床与颗粒剂

流化床造粒融合了设备、辅料和颗粒设计等多项技术。本文分析了造粒机理 ,并从造粒芯、辅料及颗粒设计等方面介绍了流化床造粒技术的最新进展     

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。     

硫基复合肥工艺路线的比较与优化

介绍了圆盘、转鼓、喷浆造粒技术生产硫基复合肥的工艺流程及技术特点;对这几种造粒技术的优缺点进行分析比较;介绍了南京化学工业有限公司对转鼓造粒技术的进一步优化,实现多元化生产。     

尿素熔融转鼓造粒技术生产有机—无机复混肥

介绍尿素熔融转鼓造粒技术和目前普遍采用的挤压造粒技术生产有机无机复混肥的工艺流程及其技术特点;对目前国内已采用的几种有机无机复混肥造粒技术的优缺点进行了分析比较;介绍了湖北中化东方肥料有限公司采用尿素熔融转鼓造粒技术生产有机无机复混肥技术方案的比较选择情况,以及装置的试生产情况。     

大颗粒尿素造粒工艺简介

介绍了大颗粒尿素造粒工艺，着重介绍了荷兰NSM公司的流化床造粒技术和法国K－T公司的流化床转鼓造粒（FDG）技术。     

尿素和硝铵造粒工艺的最新进展

尿素、硝铵的造粒一直采用造粒塔造粒。但是,随着市场对造粒塔不可能得到的大颗粒尿素和硝铵的需要量的增加,大颗粒肥料造粒新技术得到了发展,包括盘式造粒、流态床和流态鼓造粒技术。     

磷复肥造粒干燥工序中新技术的研制与开发

介绍了我国磷复肥造粒干燥工序中的喷浆造粒干燥“三内”技术和转鼓造粒干燥“封闭返料”技术的研究现状和工业应用情况。这些技术研制开发的成功为我国的磷复肥粒干燥技术的发展提供了成功的经验。     

磷复肥喷浆造粒粉料封闭循环的研究

介绍喷浆造粒“三内”技术在造粒机内实现粉料的封闭循环技术，探讨了磷复肥喷浆造粒干燥机内返料、内筛分、内破碎对造粒的影响。表明该技术根除了传统喷浆造粒过程中因破碎、筛分引起的粉尘污染，减少了物料损失，提高了热量利用率，同时彻底改善了操作环境。     

挤压造粒复混肥料之配方及其评价

近几年,我国复混肥料发展比较迅速。其加工工艺除传统的转鼓造粒或圆盘造粒外,新开发了挤压造粒技术。作为肥料的二次加工,挤压造粒工艺具有流程短、投资省、能耗低、无三废、效益高等特点,已在国内22个省(市)得到推广。我厂在挤压造粒技术跟踪服务中,根据用户的不同要求推荐了各种挤压造粒复混肥     

氮化钒粉末造粒用胶粘剂的选择

氮化钒是VT包芯线粉芯材料的一种,经过破碎后细粉很多。为了改善粉末的流动性、提高细粉的利用率,提出了分级→造粒→干燥的工艺。该工艺流程的核心是造粒,而造粒工艺的关键是选择合适的胶粘剂。通过干球成粒率、干球落下强度、干球压缩强度、干球搅拌强度和干球外观形貌的对比,证明了淀粉胶粘剂的粘合效果优于石蜡粉,说明以低温淀粉胶粘剂为造粒用胶粘剂是合适的。     

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。     

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。     

聚丙烯降解母粒的制备及应用

采用粉体造粒技术制备聚丙烯降解母粒,使降解母粒能均匀分散在聚丙烯粉料中,防止粉末状或液态降解剂形成架桥或出现黏壁造成产品波动,能在聚丙烯装置使用化学降解法生产高熔体流动速率的聚丙烯,使熔体流动速率波动范围控制为±3g/10min。     

橡胶硫化促进剂N-环己基-2-苯并噻唑次磺酰胺的团粒法造粒技术

采用团粒(聚)法制备了橡胶硫化促进剂N-环己基-2-苯并噻唑次磺酰胺(CBS)粒状产品,确定了团粒造粒工艺的最佳条件,并在此条件下进行了稳定运行实验.结果表明,用脱水后含水率为20%的CBS湿粉料为造粒原料,采用团粒法制备CBS粒状成品的最佳工艺条件:黏结剂乙烯-乙酸乙烯酯共聚物质量分数为CBS干基料的8%、湿粒含水率为34.77%,造粒盘倾角为35～45°、造粒盘转速为65 r/min,黏结剂乳液喷加时间约为10 min,造粒周期为50～60 min,烘箱干燥温度为(55±2) ℃,烘干时间为210 min;在最佳工艺条件下制得的粒状CBS性能均达到指标要求:初熔点不小于96.0 ℃,粒径为2.0～4.5 mm,粒子的平均强度在2.0～8.0 N,加热减量不大于1.00%,灰分不大于0.40%,成粒率超过60%.该粒状CBS能完全取代粉状产品,对橡胶的硫化性能无不良影响.     

Cleaner production of porcelain tile powders. Granule and green compact characterization

A new ceramic powder preparation process, the droplet-powder granulation process (DPGP), was recently proposed in pursuit of energy/water conservation and environment protection for sustainable development of the ceramic industry.This study characterizes the DPGP granules and resulting pressed green compacts and compares them with those obtained using traditional spray-drying (hereafter SD) and granulation (hereafter G) processes. Powder and granule properties (granule size distribution, flowability, microstructure, yield pressure, etc.), powder pressing behaviour, and green compact properties (microstructure, bending strength, etc.) were determined. The properties of the DPGP powder and the resulting compacts displayed an intermediate performance between those of the powders and compacts obtained by the SD and G processes, demonstrating the feasibility of the DPGP process in the pre-firing stage of porcelain tile manufacture. The study also shows that, in addition to the key spray-mixing step, the subsequent rolling treatment also plays a major role in DPGP granule formation.     

双螺杆湿法制粒关键质量属性调控机理模拟研究

针对我国造粒工艺存在关键质量属性（粒径分布均匀性、颗粒表观质量和制粒收率）难以调控的行业共性问题,基于Edinburgh Elastic?Plastic Adhesion接触模型,构建了连续异向啮合双螺杆高剪切湿法制粒过程的仿真方法,模拟研究了过程参数?粒径分布均匀性和收率的协同耦合演化规律,以此诠释了双螺杆湿法制粒关键质量属性的调控机理。结果表明,连续异向啮合双螺杆高剪切湿法制粒机能制备表面光滑的球化颗粒,粒径与粉体喂料速度呈正关联关系,而与螺杆转速呈负关联关系,制粒收率与粉体喂料速度、螺杆转速均呈现先增后减的演化规律;在粉体喂料速度为360 kg/h或螺杆转速为1 400 r/min时,制粒收率处于最佳状态,其最优制粒收率值分别为87.9 %和83.91 %;制粒粒径主要受控于颗粒平均停留时间和持有颗粒质量,且呈正关联关系,以此提出了通过粉体失重喂料装置螺杆和异向啮合双螺杆高剪切湿法制粒机螺杆的变频转速控制,在线实时调控合格颗粒粒径和收率的技术方法。     

Process intensification in particle technology: Characteristics of powder coatings produced by nonisothermal flow‐induced phase inversion

The characteristics of powder coatings manufactured through a novel processing technique based on nonisothermal Nlow‐induced phase inversion granulation enhanced by fluid injection to promote phase inversion and particle formation from melt state is summarized. Experiments were carried out in a purpose‐built granulator, which operates in a parallel disk rotor‐stator arrangement, so that the mechanism of granulation could be studied. The product of this intensive granulation was compared with that of the conventional powder coating manufacturing process. Understanding the mechanism of intensive granulation helped to redesign the equipment that resulted in smaller particles. Pigment dispersion characteristics were improved by intensive granulation. Also, the particle size span can be significantly reduced by dry granulation and gas‐phase granulation, and the flowability can be improved by wet granulation. Chemical analysis of particles by Fourier transform infrared spectroscopic analysis showed that the injection of coolant fluid had no effect on the chemical composition. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

影响压力式喷雾造粒的因素和提高效率的途径

本文对工业陶瓷生产中喷雾造粒系统工作原理及粉料工艺性能作了综述,分析了生产中压力式喷雾造粒工艺的影响因素,就如何改善粉料质量和提高运转效率提出意见.     

Quantifying liquid coverage and powder flux in high-shear granulators

A key aspect to high-shear wet granulation is the coverage of binding fluid as it first comes into contact with the surface of a powder bed. Quantifying the parameters that determine liquid coverage with respect to powder flux could improve the ability to rationally characterize and scale wet granulation processes. In this work, the surface velocity of a powder bed was measured during wet granulation in high-shear mixers (Aeromatic-Fielder) ranging from lab (25 l) to pilot (300 l) scale. High-speed video analysis revealed that surface velocity is strongly dependent on impeller speed, mixer scale, fill level, and extent of granulation. Surface velocity results were coupled with the dimensionless spray flux concept reported by Litster et al. [Powder Technol. 114 (2001) 32] to quantify liquid coverage relative to powder flux for operating conditions commonly used to granulate pharmaceutical powder blends. Dimensionless spray flux calculations suggest that granule nucleation in high-shear mixers does not take place in the drop-controlled regime. The density of spray drops at the surface of the powder bed is sufficiently high to cause a significant amount of drop overlap, thereby hindering the formation of nuclei from individual spray drops. Dimensionless spray flux calculations predict an approximate 2.5-fold increase in liquid coverage upon scaling a standard high-shear wet granulation process from 25 to 300 l. The use of multiple spray nozzles could potentially minimize differences in liquid coverage between scales. Practical limitations of the dimensionless spray flux concept are discussed and an empirically modified version of the original spray flux equation is presented.