间接加热式列管回转干燥机传热系数的测试方法

在对列管回转干燥机内传热过程进行深入分析的基础上,设计了简便、可靠的实验系统,并运用非稳态传热理论导出列管壁面与物料颗粒间的传热系数与被测量参数的关系式,从而建立了一套用于间接加热式列管回转干燥机的加热管壁面与物料颗粒间传热系数的测试方法。实验装置的传热系数测量结果显示,列管壁面与颗粒间的瞬时传热系数随筒体转动呈现周期性的变化规律,随着列管位置的升高,传热系数呈逐渐降低的趋势。通过对测试结果的误差分析表明,对传热系数测量精度影响最大的因素是紫铜管表面积,其余依次为壁面升温速率、加热电流、列管壁面温度和物料温度的测量。对常见的6种运行工况的传热系数测试结果进行了可靠性分析,结果表明,所产生的最大相对误差小于3.5%,壁面升温速率的测量误差是总误差的主要构成部分。     

煤干燥蒸汽管回转干燥机换热管泄漏检测及处理方法

针对目前工业使用的蒸汽管回转干燥机换热管泄漏、设备传热恶化和产能下降的问题,在分析换热管泄漏原因基础上,总结现场的检修经验,提出了换热管泄漏检测及快速维修的方法。     

蒸汽回转干燥机换热管开裂分析及对策

通过宏观检验、化学成分分析、力学性能测试、金相检验、扫描电镜断口分析以及能谱分析等方法,对某焦化厂蒸汽回转干燥机换热管失效原因进行了分析。结果表明:蒸汽回转干燥机换热管受到管外介质冲刷磨损减薄,形成管壁穿孔,SUS329J4L换热管成型过程中产生轴向密集型微裂纹缺陷,微裂纹的存在使得换热管的性能下降,最终开裂,S、Cl-的存在对开裂的进一步扩展起到了促进作用。更换后的SUS329J3L换热管在S、Cl-环境下发生晶间腐蚀和应力腐蚀开裂。     

大型煤泥蒸汽回转干燥装置换热管应力腐蚀失效分析

针对某大型煤泥干燥项目蒸汽回转干燥装置换热管泄漏的问题,采用X射线荧光光谱仪、扫描电镜和X射线能量色谱仪对泄漏换热管进行化学成分分析、应力腐蚀形貌和腐蚀产物分析研究,探讨加热管泄漏主要原因。结果表明,换热管泄漏的主要原因是管外环境的影响导致的应力腐蚀失效,为蒸汽回转干燥机换热管的设计制造提供有益的参考。     

金隆蒸汽回转干燥机国产化改造实践简

金隆公司充分利用公司冷修期间对蒸汽回转干燥机进行了国产化改造,在对改造前蒸汽回转干燥机存在问题进行分析基础上,重点介绍了对干燥机的改造过程。改造后,蒸汽回转干燥机运行状况稳定,达到改造目的。     

金隆蒸汽回转干燥机国产化改造实践

金隆公司充分利用公司冷修期间对蒸汽回转干燥机进行了国产化改造,在对改造前蒸汽回转干燥机存在问题进行分析基础上,重点介绍了对干燥机的改造过程。改造后,蒸汽回转干燥机运行状况稳定,达到改造目的。     

直流蒸汽发生器蒸干及蒸干后传热数值分析

准确预测直流蒸汽发生器流动沸腾及蒸干对其设计、安全可靠运行极其重要。通过对B&W公司直流蒸汽发生器进行合理简化,引入两流体三流场数学模型及壁面热通量分区模型,分别进行基于常热通量和耦合传热的蒸汽发生器流动沸腾数值模拟。结果表明：蒸干发生时传热性能急剧下降,常热通量边界下壁温升高的幅度相当大（约300 K·m^-1）,而耦合传热边界下壁温飞升幅度约为25 K·m^-1,与实际情形相一致;两种热边界中预热区会发生过冷沸腾,壁面处传热由液相对流换热、淬火换热和蒸发换热3部分构成,核态沸腾区蒸发换热为主要换热方式,同时伴随着液相对流换热和淬火换热,蒸干发生时淬火换热和蒸发换热全部降到0,在蒸干后传热区域换热方式为气相对流换热。     

金属硫化物精矿的干燥特性及干燥设备

介绍金属硫化物精矿的干燥特性、常用干燥设备的结构及使用情况.重点论述蒸汽管回转干燥机的结构、工艺流程和应用效果.蒸汽管回转干燥机通过在筒体内以同心圆的方式布置换热管及通入中低压饱和蒸汽作为加热介质,对精矿进行干燥.它具有设备处理能力大、能耗低、工艺简单、需处理的尾气量小并且含尘低等优点,适合与大型硫铁矿焙烧和有色金属硫化矿熔炼配套使用.     

直流蒸汽发生器蒸干及蒸干后传热数值分析

准确预测直流蒸汽发生器流动沸腾及蒸干对其设计、安全可靠运行极其重要。通过对BW公司直流蒸汽发生器进行合理简化,引入两流体三流场数学模型及壁面热通量分区模型,分别进行基于常热通量和耦合传热的蒸汽发生器流动沸腾数值模拟。结果表明:蒸干发生时传热性能急剧下降,常热通量边界下壁温升高的幅度相当大(约300K·m~(-1)),而耦合传热边界下壁温飞升幅度约为25K·m~(-1),与实际情形相一致;两种热边界中预热区会发生过冷沸腾,壁面处传热由液相对流换热、淬火换热和蒸发换热3部分构成,核态沸腾区蒸发换热为主要换热方式,同时伴随着液相对流换热和淬火换热,蒸干发生时淬火换热和蒸发换热全部降到0,在蒸干后传热区域换热方式为气相对流换热。     

蒸汽管回转干燥机换热管泄漏的检测及处理方法

煤泥用蒸汽管回转干燥机的换热管易受杂质砸击、化学元素腐蚀、煤泥磨损、热应力等作用而发生泄漏;论述了采用水压、气压、蒸汽和仪表元件检测其漏点的方法,介绍了换热管的维修及更换步骤。     

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。     

用颗粒热传递模型计算旋转列管干燥机的传热系数

采用基于移动加热板的颗粒热传递模型计算大型旋转列管干燥机的传热系数。在料床完全混合的简化假设下 ,按物料在干燥机内的实际干燥过程分段计算各段的传热系数及整机总传热系数 ,其结果与干燥机的实际运行情况基本相符。     

Modeling the Fractional Drying and Aerodynamic Separation of Alfalfa into Leaves and Stems in a Rotary Dryer

A computerized mathematical model was developed to predict fractional drying and aerodynamic separation of alfalfa into leaves and stems in one process in a rotary dryer. Aerodynamic separation was characterized by separation efficiency or the total amount of the desired component (leaf or stem) recovered, relative to the amount entering the process, and by purity of leaf or stem component collected at exit ports of the dryer. The model development assumed 100% separation efficiency and purity. The model was validated by comparing model predicted results with measured experimental and field test data obtained from a small industrial rotary dryer and a full-scale industrial dryer. Changes in leaf, stem, and drying gas moisture contents and temperatures were measured and predicted by the model under various drying conditions. The model-predicted results agreed well with measured data. The model was also used to simulate the performance of industrial rotary dryers under various operating conditions. The model can be used to determine the optimum drying and aerodynamic separation parameters. It can also be used to design and redesign new and existing industrial rotary dryers in order to combine drying and aerodynamic separation into one process.     

多管回转式煤调湿工艺模拟与分析

基于Fluent软件,采用欧拉多相流模型,模拟回转管内烟气(焦炉烟气)与干燥器内煤粉的流场分布、湿度和温度变化情况. 结果表明,烟气速度在入口处最大,为9.65 m/s,在回转管内最小,为3.22 m/s,烟气经转弯处汇集于中心管,速度约为6~7 m/s;靠近回转管的煤粉速度最大,远离回转管的煤粉速度最小;煤粉与水分离后,水分比例减少,煤粉比例增加,脱水率约为7%;由干燥器周边到中心煤粉密度减弱;烟气和煤粉均有温度梯度,烟气温度差约为65 K,煤粉温度差约为31 K.     

Modeling the Fractional Drying and Aerodynamic Separation of Alfalfa into Leaves and Stems in a Rotary Dryer

A computerized mathematical model was developed to predict fractional drying and aerodynamic separation of alfalfa into leaves and stems in one process in a rotary dryer. Aerodynamic separation was characterized by separation efficiency or the total amount of the desired component (leaf or stem) recovered, relative to the amount entering the process, and by purity of leaf or stem component collected at exit ports of the dryer. The model development assumed 100% separation efficiency and purity. The model was validated by comparing model predicted results with measured experimental and field test data obtained from a small industrial rotary dryer and a full-scale industrial dryer. Changes in leaf, stem, and drying gas moisture contents and temperatures were measured and predicted by the model under various drying conditions. The model-predicted results agreed well with measured data. The model was also used to simulate the performance of industrial rotary dryers under various operating conditions. The model can be used to determine the optimum drying and aerodynamic separation parameters. It can also be used to design and redesign new and existing industrial rotary dryers in order to combine drying and aerodynamic separation into one process.     

PIA预干燥技术的开发和应用

以中国石油化工股份有限公司北京燕山分公司30kt／a PIA工业装置改造为依托,通过技术调研、试验研究、方案论证,成功开发了一种盘式桨叶预干燥机＋蒸汽管回转干燥机的组合干燥技术及专用型PIA盘式桨叶干燥机技术。     

PTA装置氧化回转蒸汽列管干燥机腐蚀失效分析

PTA装置氧化回转蒸汽管干燥机因腐蚀等原因造成加热管和筒体多次泄漏 ,通过对加热管进行取样分析 ,查找腐蚀失效机理 ,为检修提供了依据     

Mathematical Modeling the Drying of Poplar Wood Particles in a Closed-Loop Triple Pass Rotary Dryer

Closed-loop drying systems are an attractive alternative to conventional drying systems because they provide a wide range of potential advantages. Consequently, type of drying process is attracting increased interest. Rotary drying of wood particles can be assumed as an incorporated process involving fluid–solid interactions and simultaneous heat and mass transfer within and between the particles. Understanding these mechanisms during rotary drying processes may result in determination of the optimum drying parameters and improved dryer design. In this study, due to the complexity and nonlinearity of the momentum, heat, and mass transfer equations, a computerized mathematical model of a closed-loop triple-pass concurrent rotary dryer was developed to simulate the drying behavior of poplar wood particles within the dryer drums. Wood particle moisture content and temperature, drying air temperature, and drying air humidity ratio along the drums lengths can be simulated using this model. The model presented in this work has been shown to successfully predict the steady-state behavior of a concurrent rotary dryer and can be used to analyze the effects of various drying process parameters on the performance of the closed-loop triple-pass rotary dryer to determine the optimum drying parameters. The model was also used to simulate the performance of industrial closed-loop rotary dryers under various operating conditions.     

蒸汽管回转干燥机在铅精矿干燥中的应用

介绍了铅精矿蒸汽管回转干燥机系统的工艺流程，针对铅精矿的特性，对干燥系统的进料方式、密封形式、除尘器、冷凝水排放系统进行了设计改进。该干燥系统运行稳定、易于操作，各项运行指标达到设计值，并且生产负荷可在30％～110％范围内调节。