转筒干燥器中物料运动模型的研究现状

综述了近年来国内外关于转筒干燥器物料运动模型的研究现状,分析了各种模型的特点及适用性,并对其今后的发展方向进行了展望。     

抄板式转筒烘干机扬料板的改造

１存在问题老式抄板式转筒烘干机（以下简称老式烘干机）因扬料板的设计不合理,烘干机热效率低,限制了生产能力的发挥。主要体现在以下几个方面。１）扬料板对物料的提升与携带能力差,在烘干机同一横截面上的不同区域物料的分布情况差别很大,热交换分布不均,因此热效率低。２）采用单一形状与结构的扬料板,使得各横截面上的物料分布情况相似,在烘干机内形成一个很大的无料空洞,热气流会在这里发生短路现象,大量的热量从这里流失。３）顺流式与逆流式烘干机工作时有不同的特点,而同一种烘干机筒体内的不同部位的工作条件又存在很大…     

转筒干燥器工艺计算顺序及参数优选

针对磷肥和磷复肥以及其他物料干燥工序常用的转筒干燥器暴露的设计问题,阐述了工艺计算之前应掌握的原始数据.介绍了工艺计算顺序及参数优选,认为许多物料的干燥都应考虑其预热段的容积;转筒干燥器的水分蒸发强度须在流体力学相似和热工条件相似的工况下选用;由于进料口处有漏风,因此热风炉至转筒干燥器的进气口处应设置低压热风机,才能达到预期的水分蒸发强度,这对燃煤热风炉尤为重要.     

炭黑工艺研究与转筒干燥器工艺计算

本文介绍了较为成熟的碳黑生产工艺,并针对碳黑干燥工序常用的转筒干燥器的设计问题,阐述了工艺计算之前需要掌握的原始数据、工艺计算顺序和参数选择。     

三弧抄板

现有转筒烘干机的抄板不能把料撒在整个转筒内 ,而且撒料也不合理 .用力学理论和实验结合得出的三弧抄板克服了这些缺点 ,并且填充率高 (>2 0 % ) .如果用于工业生产 ,必将有显著的节能效果 .     

基于Rocky DEM的松散润叶筒内抄板作用的模拟与优化

为深入研究松散润叶筒内叶片在抄板上的掉落过程,提升叶片的耐加工性,利用三维建模软件建立松散润叶筒三维模型,通过Rocky 2021 R2离散元仿真软件创建薄片柔性叶片进行数值模拟,对叶片在松散润叶筒内抄板上的运动进行可视化计算。根据抄板上叶片的持料量百分比曲线和落料速率曲线,将叶片的掉落过程分为两个阶段。结果表明：片状颗粒的受力区别于刚性球体间的点对点接触受力,叶片形状不可忽略;松散润叶筒转速为15 r/min时,叶片在筒体底部分布较少,筒体上半部分分布较多;抄板安装角度为80°时,板上持料量增多,抄板倾角较合理,增温增湿效果最优;松散润叶筒倾角对叶片在抄板上掉落的轴向速度影响显著。通过仿真得出叶片在抄板上掉落过程的优化参数,有助于松散润叶过程调控,指导实际工业生产。     

浅谈流化床干燥器布风板的设计

介绍流化床干燥器所用各种形式布风板的结构。并对其使用情况作了分析。特别对高温布风板的形式进行了探讨。     

三聚氰胺干燥器的物料衡算及热量衡算

通过对三聚氰胺干燥器进行全面的物料和热量衡算,得出一定负荷下干燥器需要的最低热空气量、蒸汽消耗、废空气露点及三聚氰胺在干燥器中的停留时间,为干燥器的运行提供了理论依据,对实际生产具有指导意义。     

三聚氰胺干燥器的物料衡算及热量衡算

通过对三聚氰胺干燥器进行全面的物料和热量衡算，得出一定负荷下干燥器需要的最低热空气量、蒸汽消耗、废空气露点及三聚氰胺在干燥器中的停留时间，为干燥器的运行提供了理论依据，对实际生产具有指导意义。     

三胺干燥器的物料衡算和热量衡算

通过对三胺干燥器进行全面的物料和热量衡量，得出一定负荷下干燥器需要的最低热空气量，蒸汽消耗，废空气露点及三胺在干燥器中的停留时间，为干燥器的运行提供了理论依据，对实际生产具有指导意义。     

Modelling and Simulation of a Direct Contact Rotary Dryer

ABSTRACT

A mathematical model able to predict solid and drying gas temperature and moisture content axial profiles along a direct contact rotary dryer was developed. The study was focused on the drying kinetics based on phenomenological models. Two different drying mechanisms in the decreasing drying rate period were tested: proponional to the unbound moisture content and moisture diffusion inside the particle. Experimental data collected in a pilot-scale direct contact rotary dryer was used to validate the model. Soya and fish meals were used as drying material.     

Modelling and Simulation of a Direct Contact Rotary Dryer

A mathematical model able to predict solid and drying gas temperature and moisture content axial profiles along a direct contact rotary dryer was developed. The study was focused on the drying kinetics based on phenomenological models. Two different drying mechanisms in the decreasing drying rate period were tested: proponional to the unbound moisture content and moisture diffusion inside the particle. Experimental data collected in a pilot-scale direct contact rotary dryer was used to validate the model. Soya and fish meals were used as drying material.     

Simulation of Wood Particle Motion Through a Concurrent Triple-Pass Rotary Dryer

The retention time of solids in a drum is an important parameter for the design of rotary dryers, since it directly influences the mass and heat transfer rates. If it is too short, the wood particles do not become adequately dried. If it is too long, they become over-dried. Therefore, having an appropriate retention time is useful in terms of both energy and plant capacity. Wood particle mean retention time in a rotary dryer is affected by several variables, such as dryer dimensions, solid characteristics, and operational parameters. The purpose of this work was to simulate the effects of some wood particle characteristics and operational parameters on the mean retention time, drum holdup, and velocity of the wood particles during drying in a pilot-scale, closed-loop, triple-pass rotary dryer by means of a computer code. The simulation results of wood particle motion can be used for modeling, design, and optimization of closed-loop, triple-pass rotary dryers.     

Modeling and Simulation of a Co-Current Rotary Dryer Under Steady Conditions

A model which joins the overall design algorithm of a rotary dryer with the drying kinetics equations derived from experimental data and with a finite segment algorithm is implemented in order to verify the dryer dimensions obtained from a basic sizing procedure. Total energy and mass balances and well-known correlations for the overall heat transfer coefficient are employed to develop it. Moreover, a one-dimensional finite segment model is solved to obtain the length profiles of temperature and water content for the air and solid phases. An experimental correlation for the mass transfer coefficient between solid and air phases is included in the finite segment model. The chosen heat transfer unit number for the basic sizing is verified with the outlet temperature and water content calculated by the finite segment scheme.     

回转干燥器的设计改进

论述传统回转干燥器的技术改进 ,并指出其发展方向     

A Three-Dimensional Simulation of a Spray Dryer Fitted with a Rotary Atomizer

Spray dryers fitted with rotary atomizers are commonly used in diverse industries to produce engineered powders on a large scale. Scale-up of such units is still largely empirical and based on prior experience and know-how. In the present study, a three-dimensional spray dryer with rotary atomizer is investigated numerically with a commercial CFD code. Continuous-phase, i.e., air, conservation equations are formulated in the Eulerian model while the droplet or particle equations are set up in the Lagrangian model. Two-way coupling between the continuous and dispersed phases is taken into account in the governing equations. The stochastic approach is used to predict the particle trajectories. The RNG k - ε turbulence model was used. Typical results, viz. air velocity, temperature, humidity profiles, and particle trajectories are presented and discussed. Compared with the pressure nozzle spray dryer, more volume of drying chamber is used effectively by the rotating disc type spray dryer. It is found that evaporation and drying take place mainly in the region and in the vicinity of first contact between air and spray. A parametric study is presented and, where appropriate, comparison is made with experimental data obtained with the simulated spray dryer.     

A Three-Dimensional Simulation of a Spray Dryer Fitted with a Rotary Atomizer

Abstract

Spray dryers fitted with rotary atomizers are commonly used in diverse industries to produce engineered powders on a large scale. Scale-up of such units is still largely empirical and based on prior experience and know-how. In the present study, a three-dimensional spray dryer with rotary atomizer is investigated numerically with a commercial CFD code. Continuous-phase, i.e., air, conservation equations are formulated in the Eulerian model while the droplet or particle equations are set up in the Lagrangian model. Two-way coupling between the continuous and dispersed phases is taken into account in the governing equations. The stochastic approach is used to predict the particle trajectories. The RNG k ? ? turbulence model was used. Typical results, viz. air velocity, temperature, humidity profiles, and particle trajectories are presented and discussed. Compared with the pressure nozzle spray dryer, more volume of drying chamber is used effectively by the rotating disc type spray dryer. It is found that evaporation and drying take place mainly in the region and in the vicinity of first contact between air and spray. A parametric study is presented and, where appropriate, comparison is made with experimental data obtained with the simulated spray dryer.     

Modeling of a Cocurrent Rotary Dryer

Parametric mathematical models of drying plants include balance equations and correlations that should be adjusted for each case depending on the material to be dried and the installation. In some cases, variable parameters are simplified as constants, providing an inaccurate model.

This article presents a model of a cocurrent dryer, showing the process by which it is arrived at, and raises suggestions for some improvements in the determination of the drying rate to obtain a more accurate analytical expression.

Preliminary tests are presented that can be performed on the solid material and the model of a pilot plant is validated.     

PTA回转干燥机的工艺设计

以某1000kt／a PTA国产化依托项目中精制干燥机为例,在研究了PTA工业装置中回转蒸汽列管式干燥机的工作原理和干燥机理、综合分析现有工业装置精制干燥机的设计与标定数据、实际物料干燥实验数据的基础上,总结了回转蒸汽列管式干燥机工艺设计方法,提出干燥机物料停留时间、总传热系数等关键设计参数的计算方法。设计结果已应用于实际项目的工程设计中。     

过磷酸钙回转圆筒干燥机的工艺计算

分析了粒状过磷酸钙的干燥特点,列举了粒状过磷酸钙回转圆筒干燥机的工艺计算,指出计算过程应考虑物料预热升温所需的热量,以及传递这部分热量所需的容积。