回转窑内传热模型的研究现状

建立传热数学模型,预测回转窑内的温度场及其热工特性是研究回转窑传热过程的一种有效手段。本文综述了回转窑传热模型的国内外研究现状,并指出建立的回转窑传热模型所存在的局限性,在此基础上,提出了自己的观点,并对以后的发展前景进行了展望。     

石油焦煅烧回转窑综合传热过程数值模拟

研究了石油焦煅烧回转窑内的物理和化学反应过程对回转窑内传热过程的影响,并在对回转窑内的物料输送过程、传质过程和传热过程具体分析的基础上,建立了石油焦煅烧回转窑的综合传热数学模型. 应用数值计算方法对传热数学模型进行计算求解,预测了窑内气体、物料和窑壁内外表面的轴向温度分布. 结果表明,窑内的高温区域主要集中在挥发分大量燃烧的区段上,三次风的注入会引起窑内气相温度的明显下降,但不会造成料床温度的明显变化;在物料与气体、窑内壁之间热交换过程中,物料与被覆盖的窑内壁表面之间的对流换热和气体与料床表面间的辐射换热为主要的传热机制. 计算预测的结果与测量数据在规律上和数值上都能较好地符合,从而为石油焦煅烧回转窑的优化设计和经济运行提供了指导和依据.     

回转窑内传热传质数学模型的建立

在深入了解回转窑内的各种物理化学现象的基础上,建立能描述高温热处理条件下回转窑内的质量与能量传递过程的数学模型,以达到指导生产过程中相对较优的操作参数的目的。并针对本文建立的回转窑传热传质数学模型提出了改进的措施,并对以后的发展前景进行了展望。     

窑炉燃烧室传热过程的数学模拟

本文对火焰传热过程中能量方程进行了离散发射处理及概率模拟计算,得出了窑炉燃烧室辐射传热过程的数学模型,并对所建立的数学模型进行了数字模拟且在计算机上实现.作为应用研究,文中对某实际窑炉燃烧室进行了理论计算及验证实验.验证结果表明:所建立的数学模型及其概率模拟的求解方法符合窑炉燃烧室实际传热过程,从而为窑炉燃烧室传热过程的数值计算指明了方向.     

回转窑内滚动状态下颗粒横向运动的影响因素的实验研究

回转窑内物料颗粒的横向运动使物料的传热和传质得到加强,其研究对于回转窑的优化设计和运行是十分重要的。本文在数学模型的基础上采用数码摄像的方法对多种物料颗粒在旋转筒体内的横向运动进行了实验研究,考察了筒体直径、旋转速度、料床内物料的动态休止角等参数对于泻落层厚度、颗粒运动速度、流量以及物料在料床表面停留时间的影响,并通过实验验证了数学模型。     

隧道窑内制品温度的研究

一、前言近年来,国内外许多学者致力于研究隧道窑内的传热过程。如日本学者高津学提出了一种用于数学模拟的隧道窑传热数学模型。中国学者谷同恩、宋耑1985年提出了多种过程的火焰隧道窑预热带的传热数学模型。本文采用连续测定全窑的气体温度、流量等有关数据,然后建立窑内制品传热的二维数学模型。用此模型分析制品的传热特点。     

回转窑内物料运动与传热特性分析

回转窑燃烧具有产能大、投入少的特性,主要通过在回转窑内利用高温进行加热,排除原料中的水分以及挥发的部分,促使原料的密度以及自身稳定性等都有一定的改变。利用回转窑进行的燃烧,能够适用于大部分原料,生产过程的操作也比较容易实现。本文简要阐述了回转窑料床特性以及床态特性等内容,并在此基础上详细分析了回转窑横截面内传热特性等。     

多孔介质内部传热传质规律的研究进展

多孔介质中的热质交换理论及其实验研究是一个涉及面广、研究难度大而又颇具工程应用价值的课题。本文对多孔介质内部传热传质规律的研究从理论和实验两方面作了简要的综述及展望,并对一些描述热质传递过程的数学模型及方程作了介绍。     

提高金属换热器换热效率的研究

本文主要研究应用蒙特卡洛法模拟辐射式金属换热器内的辐射传热过程，并建立了换热器综合传热的数学模型，在蒙特卡洛法中，系统被分为体积区和表面区，利用概率论原理，把辐射能迁移过程模拟为一定累积概率分布下的随机过程。所建立的数学模型分别考虑了辐射传热和对流传热，烟气的吸收系数的变量，能较好地反映换热器内传热过程的真实状况。运用本文叙述的方法可以计算出换热器内烟气、筒壁、空气的温度和壁面热流分布，以及研究烟     

危险废物回转窑焚烧炉在线红外热成像测温及其耐材状态监测研究

回转窑作为危险废物焚烧装置的核心生产设备,对其工艺状况进行全面监控显得尤为重要。在实际生产过程中,回转窑内耐材减薄、裂纹、表面爆裂脱落、坍塌等损坏引起的斑点窑、红窑甚至窑筒体腐蚀穿是影响危险废物焚烧装置长期安全稳定运行的关键问题,如能实现实时回转窑工艺状况全面的动态监测进而更好的采取技术措施,将有利促进危险废物焚烧装置回转窑安全平稳运行。本文结合传热学知识,分析了回转窑的传热类型,且进行了详细的传热模型计算,以期望基于此能够为回转窑耐火材料的动态实时监测提供理论支撑。     

Drehrohrreaktoren in der Chemietechnik

Rotary kiln in chemical engineering. This review stresses the importance of rotary kilns in industry. After a brief account of design considerations, the following processes are treated: particle and product motion, longitudinal and transverse transfer of solids, mass- and heat transfer, as well as chemical reactions. Common models used for rotary kilns are discussed. Typical industrial processes employing rotary kilns are presented. The present status of control and automation of these plants are discussed.     

Mathematical modelling of rotary cement kilns by the zone method

A steady state mathematical model of rotary cement kilns based on the fundamental principles of the physical and chemical processes within the kiln was developed. The zone method of analysis was utilized together with the Monte Carlo method to simulate the radiative interchange within the kiln. Steady state energy balances including the chemical reaction terms for each zone were solved simultaneously to give temperature distributions in gas and solid charge, and composition distribution in solid charge. Predictions of the mathematical model were compared with dry process and wet process rotary cement kiln data.     

Simulating the mixing and segregation of solids in the transverse section of a rotating kiln

Rotating kilns are widely used in industry to process granular material. These processes include calcination of mineral ores, drying of foods and grains, combustion of wastes and manufacturing of pharmaceuticals. Since models developed for a particular process are often unique to that process there is a need to develop more generic models to predict the mixing and segregation in the transverse section of a rotary kiln.This paper presents a mathematical simulation - based on experimental observations - to estimate the mixing rate, final extent of mixing and the final distribution of material due to segregation. The models used in the simulation allow for scale-up of processes to produce a simulation that is applicable to a broad range of industrial processes. Independent experiments were used to verify the simulation and it was found that the mixing rate, the final extent of mixedness and the final segregated state could be predicted to within acceptable errors.     

Optimal control of annealing during the preparation of aluminum hydroxide and cement clinker in tubular rotary kilns

A mathematical model of the preparation of aluminium hydroxide and Portland cement in tubular rotary kilns has been developed. Experimental data have been obtained by TG DSC on a NETCH calorimeter; mathematical models of reactors have been obtained based on an analysis of the motion of multiphase systems. The models of reactors have been used to solve the problems of optimizing the temperature profile in apparatuses using technological criteria of optimization by nonlinear programming methods.     

水泥窑协同处置危废浅析

针对我国目前危险废弃物的处置方法主要以焚烧和安全填埋为主的现状,采用水泥窑协同处置危废的方法,利用已有回转窑,通过对水泥窑协同处置危废的工艺分析,该方法具体优点体现在:煅烧温度高,高温停留时间长,湍流碱性工况,危险废物无害化彻底;焚烧灰渣直接利用;危险废物中有机、无机成分得到了充分利用;排放气体高效处置;回转窑热容量大,工况稳定,危险废物处理量大。     

搅拌釜内流场实验研究与数值模拟的进展

概述了搅拌釜内流场实验研究与数值模拟的进展,介绍了速度场、混合时间、循环流量和温度场的各种测量方法,同时就搅拌釜内流场数值模拟中涉及的各种湍流模型以及旋转桨叶的处理方法进行了对比分析。最后指出传热特性、多相流以及多参数耦合数学模型是搅拌釜研究的重点。     

Temperature distribution within the moving bed of rotary kilns: Measurement and analysis

Inadequacies in the temperature measurement within the moving bed have hindered a thorough understanding of the processes occurring within rotary kilns. A new measuring system, consisting of thermocouple arrays, a radio-transmitter, a radio-receiver and a computer monitor is introduced in this paper. With it, the 3D temperatures within the moving bed, as well as the temperatures of the freeboard gas and the kiln wall, can be measured and saved automatically. Experiments with sand on a co-current pilot kiln demonstrated that, in the passive layer of the moving bed, the temperatures were approximately constant in the circumferential direction. In the radial direction, however, large temperature difference was observed within the bed near the feed end of the kiln, and the difference became smaller as the bed went progressed through the kiln. This temperature measuring system can be used to obtain data over a wide range of operating conditions for use in engineering design. The obtained results may give new thoughts in theoretical modeling of heat transfer within the moving bed of rotary kilns.     

热辐射涂料在陶瓷辊道窑中的节能机理与应用

基于辐射传热原理,本文详细分析了热辐射涂料在陶瓷辊道窑中应用的节能机理,理论分析和实际应用都表明在辊道 窑中应用热辐射涂料后可以有效地增强炉膛中的辐射传热,从而提高辊道窑的热效率,节能效果显著。     

在陶瓷梭式窑中应用高效热辐射强化剂的节能实践

基于辐射传热原理，本文详细分析了高效热辐射强化剂在陶瓷梭式窑中应用的节能机理，理论分析和工业试验都表明在梭式窑中应用高效热辐射强化剂后可以有效地增强窑内的辐射换热，从而提高梭式窑的热效率，达到显著的节能降耗效果。