【作者】 王明超；

【导师】 柴立和；

【作者基本信息】 天津大学 ， 环境科学， 2008， 硕士

【摘要】 循环流化床锅炉是近年来发展起来的一种新型炉型,作为一种新型高效低污染燃煤技术,在国内外已得到广泛应用。为了保证锅炉工作的安全可靠和节约能源,当今锅炉工作者的工作重点往往着眼于锅炉受热面外部过程,即燃烧产物对锅炉受热面烟气侧工作的影响。但是随着煤粉炉大型化及以生物质为新开发燃料的应用之后,流化床锅炉遇到了普遍性的积灰结渣危害问题。本文采用新的视角和研究方法对流化床积灰结渣过程和形态进行研究,从以下4个方面进行了具体分析:首先,分析流化床积灰结渣的机理以及影响因素,比较不同的运行参数在数学建模和实际工程中对积灰结渣的影响,并分析工程中常用的数学模型存在的问题和优缺点;第二,以扩散限制凝聚模型为基础,对灰颗粒在炉内凝聚生长的过程进行模拟和分析;第三,对燃料和灰颗粒在受热面上的积灰结渣生长过程进行建模和模拟,并对模拟结果进行分析;第四,利用迭代函数系统(IFS)方法对积灰结渣的结构建立数学模型,并对其动力学过程进行分析。本文在分析和解决循环流化床积灰结渣问题中提出了新的观点和方法,即利用分形理论对灰粒凝聚体和受热面上积灰结渣的生长过程进行模拟和分析,并提出建立函数迭代系统模型对积灰结渣结构进行研究和模拟。运用此新的方法,模拟结果取得理想的结果。本文的最大成果即利用分形理论对积灰结渣过程进行分析建模,特别是利用MATLAB语言编写计算机程序,模拟颗粒凝聚体的形成过程和特性、受热壁面上积灰结渣的动态生长过程、以及利用迭代函数系统对积灰结渣结构建立数学模型,此三方面是本文的创新点。文章最后对以后的研究方向和分形理论在流化床锅炉燃烧过程中的应用进行了前景分析和展望。更多还原

【Abstract】 Circulating fluidized bed boiler developed to be a new furnace in recent years. As a new type of high efficiency and low pollution technology, it has been widely used at home and abroad. In order to ensure safe and economizing energy of boiler, nowadays boiler workers always focus on boiler heating surface external process, that is, the effect of combustion production to boiler heating surface. But as boiler becomes large and biomass is applied as new development fuels, fluidized bed boiler fouling encountered universal harm of slagging and fouling. This paper, adopting new perspective and research methods, studies the slagging and fouling process and form of circulating fluidized bed boiler, and does specific analysis from the following four aspects: First of all, analyzes the mechanism and impact factors of fluidized bed slagging, compares the impact of different operating parameters on slagging and fouling in mathematical modeling and practical engineering, and analyzes the advantages and disadvantages of mathematical model generally used in engineering; Secondly, based on diffusion and limited aggregation model, simulates and analyzes the process of ash particles agglomeration and growth in the furnace; Thirdly, modeling and simulates the process of fuel and ash particles fouling and slagging in heating surface, and analyzes simulation results; Fourthly, using IFS (IFS) method, establishes mathematical model of the structure of fouling and slagging, and analyzes its dynamics process.This paper puts forward new viewpoints and methods in analyzing and solving the problem of circulating fluidized bed fouling and slagging, that is, using fractal theory simulates and analyzes fouling and slagging growth process of ash particles agglomeration and heating surface, and proposes establishing iteration system model to study and simulate the structure of fouling and slagging. Using this new method, simulation achieves desired results. The biggest achievement of this paper is using fractal theory for analyzing and modeling fouling and slagging process, especially using MATLAB language for compiling computer program to simulate the formation process and characteristics of particle cohesion, dynamic growth process of fouling and slagging on heating wall, and using IFS to establish mathematical model of the structure of fouling slagging, these three aspects are creative achievements of this paper. Finally, analyzes intending research orientation and the prospects of the application of fractal theory in fluidized bed boiler combustion process.更多还原