流化床喷雾造粒的研究

<正> 流化床喷雾造粒(简称流化造粒)是将溶液、悬浮液、熔融液或粘结液喷雾到已经干燥或部分干燥颗粒的流化床床层内,在同一设备内一步完成蒸发、结晶、干燥或化学反应的造粒过程。由于流化造粒法与传统的造粒法相比,不仅工艺流程简单、设备装置紧凑、投资省、生产强度大、能耗低等优点,而且所得到的产品颗粒度要比喷雾干燥法大十倍,同时,产品无灰、无块,具有良好的流动性能,大大改善了生产和使用过程中的飞灰损失和环境污染。又由于流化床的床层温度分布均匀,     

洗涤用酶制剂的造粒技术研究

阐述了洗涤用酶微丸的3种常用造粒方法。并进一步阐述了造粒设备的基本原理和优缺点及其工业化生产的可能性。喷雾造粒法一般应用于生产粉剂和微小颗粒。挤压造粒法的处理量大、成本低,适合大规模生产。流化床造粒喷雾法制出的微丸颗粒圆整、储存性好,极大地增强了颗粒的湿热能力,并且在设备中一步完成混合、喷雾、制粒和干燥等过程,但对设备要求高,设备较为昂贵。造粒是一项复杂的物理过程,要综合考虑造粒设备、成本、生产效率和颗粒质量等因素,将上述3种造粒方法结合也是如今的研究热点。     

喷雾流化床造粒的层式生长模型试验

本文对喷雾流化床造粒过程中颗粒的层式生长进行了理论分析研究,得出了造粒层式生长模式下颗粒质量随操作时间变化的线性增长模型,并通过喷雾流化床对玻璃球的包衣试验对此进行了验证。试验表明,颗粒相对质量的增长速率大小可用来初步判断造粒过程颗粒的成长方式。     

喷雾流化干燥试验研究分析

本文在实验研究和生产运行实践的基础上,提出了流化床内颗粒上的薄膜干燥物理模型。并用此来对流化床内的流化状况、流化床内床层温度的分布、颗粒上薄膜厚度以及薄膜干燥时间等问题进行了分析,最后导出了喷雾流化生产设备最大生产能力关系式,可供设计及生产运行分析时参考。     

制取颗粒肥料的新型流化床造粒塔

本文介绍一种新型结构的流化床造粒塔,在此设备中可以同时进行干燥和造粒过程。镇江硫酸厂用于制取粒状钾硫磷铵三元高效复合肥料,经较长时间连续运转,操作稳定,制取了合格的产品,该设备还可根据要求调节产品的颗粒大小。     

杭州钱江干燥设备有限公司：GPQ微型多功能干燥实验机

公司简介 杭州钱江干燥设备有限公司是中国通用机械干燥设备行业协会副理事长单位和首批重点骨干企业、浙江省优秀科技型企业。是一家从事热力干燥技术开发、设备制造、销售、安装和技术咨询服务于一体的高新技术企业。公司成立二十多年来,已为化工、石化、精细化工、轻工、制药、食品、农副产品、矿产品、陶瓷、冶金、建材、木材、造纸、磁性材料等行业提供了近千套干燥设备。公司还相继开发了内加热流化床干燥机、耙散卧式流化床干燥机。粗颗粒喷雾造粒流化床千燥机、过热蒸汽干燥机等新产品,也受到了用户的好评。     

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     

硝铵磷铵混肥振动流化床喷雾造粒实验研究

以油菜籽为模型晶种 ,进行硝铵磷铵混合液的流态化喷雾造粒实验 ,比较了固定流化床和振动流化床两种喷雾造粒工艺。实验结果表明 :振动流化床造粒产品粒径均匀 ,表面平整 ,颗粒强度高。建立了振动流化床造粒产品粒径简化模型 ,并与实验数据进行比较 ,验证了模型的正确性     

内热式振动流化床喷雾造粒试验研究

为了开发内热式振动流化床造粒技术的潜在应用价值,对流化床喷雾造粒装置进行改进,同时引入了机械振动和内置加热管群,并以1.6 mm磷酸铵颗粒为晶种,磷酸铵溶液为浆料,在不同操作条件下进行喷雾造粒特性试验.试验结果表明:①在同样的进气温度下提高流化气速会加快颗粒生长,过大则导致粉尘生成率增加;②内加热功率的增大有利于提高颗粒的生长速度;③振动频率和振幅对颗粒成长的影响相似,适度的振动有利于颗粒成长,过大则使粉尘生成率提高.根据试验数据拟合了颗粒生长的经验公式,计算值与试验数据的误差在15%以内.     

法国K-T公司的大颗粒尿素工艺

１简要介绍Ｋ－Ｔ公司的流化床转鼓造粒（ＦＤＧ）工艺结合了转鼓造粒和流化床技术的特点,能适应多种不同物料,可用于熔化盐造粒,增大晶粒尺寸或加厚涂层,密质挤压,灰浆造粒。其主要特点如下：（１）操作简单。仅用一台设备就保证造粒和干燥效果,造粒的尺寸通过调整...     

CFD Simulation on Drying and Dust Integration in Fluidized Bed Spray Granulation

Fluidized bed spray granulation is used to produce porous granular particles from suspensions, solutions, and melts. In this work, the drying of the spray and the drying of the particles in the fluidized bed are simulated using the Two Fluid Model (TFM) with the Eulerian-Eulerian approach. Using the wetted surfaces of the particle, the dust integration is implemented. The model is used to simulate the particle growth for a semi-batch fluidized bed spray granulation process.     

ProCell technology: Modelling and application

Spouted bed processing can be considered a special processing option in particle technology. In contrast to standard fluidized beds, particles are fluidized by a gas jet in a strongly conical or prismatic process chamber.Based on this technology, Glatt developed the innovative ProCell processing unit in order to carry out various processes like spray granulation, coating, agglomeration and heat transfer.The first part of this paper is an introduction into the principle of ProCell units.In the main part results of basic research activities on fluid mechanical behaviour of ProCell apparatuses are explained and discussed. Studies on particle movement are shown which are simulated based on CFD using the Euler-granular approach. Finally a short overview on the main fields of application closes the article.     

3D simulation of effect of geometry on minimum fluidization velocity and flow regimes in a spout-fluidized bed

Spout–fluid beds are used for a variety of processes involving particulate solids, like coating, drying, granulation and etc. The spout–fluidized bed combines a number of favorable properties of both spouted and fluidized beds. In this study, the Granular Eulerian model is used in 3-D hydrodynamic simulation of spout fluidized bed for calculation of minimum fluidization velocity. The results of simulation were compared with experimental data and good agreement was obtained. Then the effect of geometry on minimum fluidization velocity was studied. Also a review of flow regimes in different spout fluidized bed geometries was studied.     

Study of dynamic multi-dimensional temperature and concentration distributions in liquid-sprayed fluidized beds

A physically based model was developed for heat and mass transfer processes in liquid-sprayed fluidized beds. Such fluidized beds are used for granulation, coating and agglomeration. The complex correlations of a number of microprocesses, spraying, wetting, drop deposition, heat transfer, drying and mass transfer were studied, and transient three-dimensional distributions of air humidity, air temperature, particle wetting efficiency, liquid film temperature, particle temperature, local liquid loading and local evaporation rate were calculated. For the evaluation of the model, the stationary spatial air temperature distributions were measured at a fluidized bed pilot plant of the institute. The fluidized bed of monodisperse wood- or glass beads was sprayed with clear water. Conclusions are drawn on the relevance of particle dispersion, spraying and drying to simulating temperature and concentrations distributions.     

Granulation of a hardmetal powder for spark plasma sintering

A fluidized bed granulation method, pressure swing granulation (PSG), was applied to granulation of a hardmetal powder without pressing lubricants for making the upstream process of spark plasma sintering (SPS) more efficient.

The properties of the granules were examined and compared with those of spray dried granules and extruded ones under the present system using a sieve.

Spherical granules between 0.15 and 0.84 mm in diameter difficult to obtain by the spray drying were obtained with high yield. The flowability of the granules was far better than that of spray dried granules and similar to that of extruded ones. Iron contamination and oxidization during pressure swing granulation were tolerable to the real production.     

污泥干燥焚烧一体化中热量计算的探讨

介绍了几种常用的污泥干燥焚烧一体化技术及其设备,分析了污泥在转筒干燥-循环流化床焚烧一体化设备中的热量输入、输出过程,对污泥干燥以及焚烧设备的设计有一定的参考价值。     

Kontinuierliche Wirbelschicht-Sprühgranulation

Continuous fluidized bed spray granulation. Spray granulation in a fluidized bed can transform originally liquid products (suspensions, melts, solutions) into freeflowing, largely dust-free granular solids. In the ideal case, the process steps of nucleation, drying/crystallization, shaping, and selective exiting of those particles which have reached the desired size proceed simultaneously in a single unit. The present contribution describes the state of the art of this process as presented in the literature.     

大型射流流化床混沌特性的研究

1 INTRODUCTIONJetting fluidized beds have been widely applied in suchprocesses as catalytic and flame reactions,combustionand gasification of coal,treatment of waste,cleaningof dusty gases,coating and granulation.The flowcharacteristics of jetting fluidized beds are relevant tothe stable gas jet and the high rates of heat transfer     

Effect of injection-nozzle operating parameters on the interaction between a gas-liquid jet and a gas-solid fluidized bed

The objective of the present study was to provide insight into the effect of operating conditions on the performance of gas-assisted nozzles injecting liquid into gas-solid fluidized beds. Acquisition of such knowledge is relevant to many industrial applications where liquid injections into fluidized beds of solid particles are performed via spray nozzles. In the fluid coking process, for example, product yields and reactor operability strongly benefit from a rapid and uniform distribution of the liquid feed on fluidized solid particles, which, in turn, is greatly affected by the performance of the liquid-injection system used.A novel experimental technique was employed to investigate the effect of varying the air-to-liquid ratio (ALR), the liquid mass flow rate, and the nozzle size on the contact efficiency of injected liquid on fluidized bed particles. Increasing the ALR or the liquid flow rate increased the nozzle spraying efficiency. On the contrary, increasing the nozzle size while keeping the gas and the liquid flow rates constant, and hence decreasing the pressure at the nozzle tip, lowered the liquid-solid contact efficiency.The effect of increasing the ALR on the liquid-solid contact resulting from nozzle-injections into the fluid bed, was correlated to both the nozzle atomization performance, as determined by open-air tests using a laser-photocell equipment, and the solids entrainment into the gas-liquid jet, as predicted by a model.     

Coupled CFD-PBE Simulation of Nucleation in Fluidized Bed Spray Granulation

Fluidized bed spray granulation is used to produce porous granular particles from suspensions, solutions, and melts. It is the general aim of our work to provide a physics-based simulation tool for this process. For this the process-relevant mechanisms such as droplet deposition, dust integration, and drying are implemented using computational fluid dynamics (CFD) to generate growth kinetics of the granules and of the dust particles. The latter gives rise to the nucleation rate. This kinetics is applied to simulate the development of the particle size distribution of granules for a continuously operated fluidized bed spray granulation process using population balance equations of the granules.