【作者】 周陵生；

【导师】 姜秀民；

【作者基本信息】 上海交通大学 ， 热能工程， 2009， 博士

【摘要】 含油污泥是石油开采和加工过程中产生一种有害污泥,它不仅占用大量的土地资源,对周围的土壤、空气、地下水都会造成污染。针对含油污泥自身的燃烧特性,上海交通大学提出一种采用异密度循环流化床焚烧处理含油污泥的方法。异密度循环流化床是一种采用石英砂颗粒作为流化床媒体物料、组合式高温漩涡分离器、炉膛为变截面结构形式的循环流化床。为了更好地应用这种异密度循环流化床焚烧处理含油污泥的技术,本文结合含油污泥的燃烧特性,建立了异密度循环流化床炉内焚烧含油污泥的整体数学模型,通过编制程序计算出相关炉内参数,并与现场试验数据进行对比与分析。首先,对含油污泥的燃烧特性进行了实验研究,给出了含油污泥样品的理化特性数据,进行了含油污泥的热解与燃烧热重分析与差热分析实验,通过对比分析了含油污泥的燃烧与热解的热重曲线,发现含油污泥的可燃物质来自于其热解产物。为此,在不同温度下,进行了含油污泥的恒温热解研究,测定了含油污泥在不同温度下主要热解产物的产率,并给出了这些热解产物的产率以及挥发分析出的实验关联方程式。另外,还在一个小型流化床实验台进行了含油污泥的燃烧实验,实验表明含油污泥不仅在密相区发生燃烧,而且在稀相区已有一部分挥发分燃烧。其次,建立了异密度循环流化床相关的子模型,主要包括炉内传热模型与流动模型。并重点研究了石英砂床料磨损与破碎模型、密相区表面固体颗粒夹带率的数学模型、组合式高温漩涡分离器的分级分离效率模型等。在完成这些子模型之后,结合这些子模型构建了非等高小室模型。即依据所建各子模型,构建各小室的质量平衡方程与能量平衡方程来求解炉内的温度分布、炉内传热系数分布以及气相成分分布等炉内燃烧特性参数。最后,进行了20t/h异密度循环流化床炉内焚烧含油污泥现场实验。描述了20t/h异密度循环流化床焚烧处理含油污泥现场启动、调试与运行测试方法。对比分析了掺烧水煤浆的三种工况实验数据与整体数学模型结果,发现模拟计算值与实验值都基本吻合,这说明本论文所建立的异密度循环流化床焚烧处理含油污泥炉内整体数学模型是合适的、可靠的。之后,以所建立整体数学模型为基础,通过改变整体数学模型中的相关参数,包括含油污泥的焚烧处理量、含油污泥挥发分含量、灰分含量与水分含量、过量空气系数、炉膛高度及受热面面积等参数,来模拟分析这些参数的变化对炉内燃烧特性的影响。模拟发现炉内温度一般随含油污泥的焚烧处理量的增加、含油污泥挥发分含量的增加、灰分含量与水分含量减少、炉膛高度与炉内受热面面积的减少而增加。但是,过量空气系数的变化对炉内温度的影响在炉膛下部和上部呈现出不同的特点。在炉膛下部,当过量空气系数增加时,由于送入的冷风量增加,床温会随着过量空气系数增加而降低,而在炉膛上部,过量空气系数过高或过低都可能导致炉温下降。除此之外,还同时模拟分析了其他炉内燃烧特性参数如炉内换热系数、烟气成分随这些参数变化的影响结果。更多还原

【Abstract】 Oily sludge is one kind of hazardous sludge, which is usually, generated during the crude oil exploitation and processing activities. Oily sludge has contamination on soil, air, and underground water. According to the combustion characteristics of oily sludge, incineration of oily sludge in the differential density circulating fluidized bed is generally adopted. As mentioned herein, the term“different density circulating fluidized bed”refers to a circulating fluidized bed with an interior horizontal cyclone separator, variable section, and quartzite particles as its bed materials. In order to optimize this kind technology, an overall mathematical model on differential density fluidized beds for the incineration of oily sludge was developed. Some parameters were obtained from a compute program. And the computed value from the overall model was close to the experimental value.Firstly, the proximate analysis, ultimate analysis, low heating value, contents and group composition of chloroform extract and the inorganic materials of the oily sludge were given. In order to further investigate and obtain the combustion characteristics of oily sludge, the pyrolysis and combustion of oily sludge were studied through some thermal analyses, which included the thermogravimetric (TG) analysis and the differential thermal analytical (DTA) analysis. It was found that the combustion of oily sludge might be the combustion of the products of its pyrolysis. Secondly, an experiment for measurements of main components of the volatile from oily sludge pyrolysis was carried out. Some mathematic correlations about the compositions of volatile from oily sludge devolatilization were achieved on the experimental results. Finally, the combustion experiment of oily sludge was carried out in a lab-scale circulating fluidized bed. It was found that the release and combustion of volatiles from oily sludge took place not only in the dense region but also in the dilute region.Secondly, some sub-models of the differential density circulating fluidized bed including the heat transfer model and the hydrodynamics model were developed. Morevoer, the model on attrition and fragmentation of quartzite particles as medium material, the model on solids entrainment flux on the surface of the dense region, and the model on separation efficiency on cyclone separator, and so on, were especially studed. On the other hand, a kind of so-called unequal height cell model combining the above-discussed sub-models was developed so as to achieve the temperature distribution, the heat exchange coefficient distribution, and concentration profiles of the main combustible components of the oily sludge combusted in the bed.Finally, some experiments were carried out in one 20t/h differential density circulating fluidized bed. To the beginning, the startup, debug, and operation of the 20t/h differential density circulating fluidized bed were introduced. And then, we compared the experimental results of three behaviour of co-firing of oily sludge with coal–water slurry with their predicted results. It was found that the experimental results were close to the simulation results from the developed overall mathematical model, which showed that the overall mathematical model was appropriate and reliable for simulation of the incineration of oily sludge in a differential density fluidized bed. Based on this developed overall mathematical model, some main parameters were introduced to simulate incineration of oily sludge in a differential density fluidized bed. Those parameters included the feed of oily sludge, the volatile content of oily sludge, the ash content of oily sludge, the water content of oily sludge, the excess air factor, the height of the bed, and the aera of the heat exchange. The results of simulations showed that the bed temperature increases with the increase of the feed of oily sludge, the increase of the volatile content of oily sludge, the decrease of the ash content of oily sludge, the decrease of the water content of oily sludge, the decrease of the height of the bed, and the decrease of the area of the heat exchange. However, in the lower part of bed, the bed temperature decreases with the increase of the excess air factor, but in the upper part of bed, it was found that the bed temperature would decrease while the excess air factor deviates from some value of the excess air factor. In addition, the simulations of the changes of those parameters to the heat transfer coefficient and the main flue components were done simultaneously.更多还原