大型回转窑节能运行关键问题的科学基础

It is the problem of low thermal efficiency and high energy consumption that is awaiting for change in the rotary kiln operation period. So this project intends to provide scientific basis for energy-saving operation of rotary kiln. The heat and mass transfer mechanism of feed, multi-movement patterns and multiple fluid will be studied: firstly, motion model of the discrete elements will be built based on the research in the transmission rule of the mixture and diffusion of the feed at particle level; secondly, heat exchange model of multiphase will be constructed after the influences that phase stat, particle motion and contact deformation have on the heat and mass transfer, and the laws of scientific regulation will be explored in bettering the heat transferring efficiency. In addition, the mechanism of heat transfer and diffusion in wall, kiln liner, kliner coating and multi-layer ring structure of feed will be researched: firstly, the formation mechanism of kiln liner will be revealed and the heat and mass transfer model will be set up; secondly, the contact thermal resistance between the multi-layer circular structures and its influencing factors will be analyzed; thirdly, the multi-layer contact heat transfer model and the heat diffusion model of the kiln body will be founded, in order to reveal the scientific regulation in reducing heat diffusion of rotary kiln. Furthermore, holographic simulation analysis in the integrated thermal processes will be conducted, so as to provide scientific basis and theoretical support for energy-saving operation of rotary kiln.

回转窑运行热效率低、能耗高的现状迫切需要改变。本项目以为回转窑节能运行提供科学基础为目标展开研究。 研究窑内多相态、多运动形态、多种类流动体的传热传质机理：从颗粒层面研究物料的混合、扩散、传输规律，建立窑料的离散元运动模型；研究窑料相态、颗粒运动和接触变形等对传热传质过程的影响规律，建立窑内气-固-液多相流的热交换模型，揭示提高回转窑热交换效率的科学调控规律。研究筒壁、窑衬、窑皮、窑料多层环形结构的热量传递及耗散机理：揭示窑皮的形成机制，建立描述窑皮形成过程的传热传质模型；分析多层环形结构层与层之间的接触热阻及影响因素，建立多层接触体接触传热模型和筒体的热量耗散模型，揭示降低回转窑热量损耗的科学调控规律。进行大型回转窑综合热工过程全息仿真分析，优化运行参数，为回转窑的节能运行提供科学基础支撑和理论指导。

回转窑在冶金、建材、化工等行业中应用广泛，其运行过程中热效率低、能耗高，物料在回转窑内的运动及传热过程复杂，其规律尚未被完全揭示。本课题首先从微观颗粒角度研究物料运动、混合、扩散、分离等传质规律及颗粒导热、对流、辐射等传热规律；随后研究了窑衬材料耐热、耐腐蚀性的变化规律，建立了回转窑筒体热量耗散模型；最后研究了回转窑内气体燃烧模型，并将燃烧模型与离散元传质模型、离散元传热模型及筒体耗散模型进行耦合。本课题从微观颗粒层面研究了影响回转窑传热效率的关键科学问题，并从宏观上建立了物料、烟气、窑衬、筒壳的气-固-颗粒多相耦合模型，为改善回转窑高能耗问题及运行过程中最佳工况的改进提供了理论基础。