【作者】 何必繁；

【导师】 王里奥；

【作者基本信息】 重庆大学 ， 环境工程， 2011， 博士

【摘要】 污泥（sewage sludge）是污水处理过程产生的主要副产物,因其含有大量致病菌和重金属而往往具有长期毒性和不可降解性,对于污泥的处理处置和资源化利用研究一直以来都是深受关注的重大课题。本次研究通过X射线衍射分析、傅里叶红外光谱分析、激光粒径分析、氮气静态吸附比表面积测试与孔径分析、原子吸收分光光度法、TG-DSC综合热分析法和量热仪燃料热值分析等技术手段研究污泥、粉煤灰、河道底泥以及陶粒配方坯料球的物理、化学及热反应动力学特性表征;根据描述试样物质主要热反应阶段特征的最概然机理函数,采用二次多项式非线性拟合方法模拟TGA变化趋势。根据正交实验设计方法,结合适宜烧制膨胀型陶粒的最佳原材料化学组成设计坯料配合比实验,通过重复实验找寻烧制污泥陶粒的最佳物料配合比;以正交实验设计方法开展弧叶型旋转窑烧制陶粒轻集料的焙烧工艺参数最优化研究,探索焙烧工艺参数影响陶粒主要产品性能品质的变化规律。结合前文研究所得烧制污泥陶粒的最佳原材料质量配合比以及烧制污泥陶粒的弧叶型旋转窑焙烧工艺参数,依托中型弧叶型旋转窑开展烧制污泥陶粒轻集料放大实验实验研究,分析焙烧流程烟道气体产生特征;通过附带X射线微区能谱分析设备的扫描电子显微镜观察陶粒产品表面、剖面的微观结构特征以及产品微区元素含量分析;全面分析了污泥陶粒产品的建材特性品质和环境安全性指标;简要论述了污泥陶粒的应用范畴。通过以上各方面的研究得到以下主要结论:1)实验用污泥试样的挥发性固体含量约为32.09%;样本的粒径大致呈现正态分布,其粒径处于39.9μm¹002.37μm范围的污泥颗粒物占总量的89.1%,平均粒径为235.793μm;BET比表面积较小,多孔结构不明显。污泥可能包含的官能团物质有:水合结晶物、CO₃^2-、酰胺类C=O、SiO₄^2-、-CH₃、R₂CH₂和苯环异构体基团物质等;干基污泥的结晶度不高,样本中含有一定量砂粒,含有粘土类矿物质,所含晶体种类主要为α-石英相。2)随着升温速率的增大,污泥试样最大失重速率以及最大失重速率对应的转化率单调减小,达到最大失重速率的温度单调升高;试样总失重率受升温速率的影响无明显规律可循;污泥试样综合燃尽特性指数随升温速率提高单调减小。试样在空气氛围下的热反应过程遵循独立而又平行开展的简单热反应机理模式;最概然机理函数绘制的模拟TGA曲线能够精确揭示实验TGA曲线的热失重变化过程。污泥试样的干燥无灰基热值约为23.25 MJ/kg,具有燃料价值,能够在一定条件下实现自持燃烧。3)实验用粉煤灰的硅、铁、钙等主要元素的百分含量稍高于我国粉煤灰含量的平均值,铝和氧元素的含量以及烧失量低于平均水平;粉煤灰的堆积密度为835.24 kg/m³,其粒径分布大致呈现正态分布,平均粒径为106.504μm;粉煤灰试样的BET比表面积较小,约为0.56 m²/g;其BJH平均孔径为7.4982 nm,孔容仅为0.001027 cm³/g,多孔结构不明显。粉煤灰试样在空气氛围、不同升温速率下存在一个主要的热失重阶段。河道底泥主要氧化物含量与粘土背景值比较接近,主要存在碳酸盐、硅酸盐化学基团物质;底泥样本的BET约为13.0893m²/g,BJH平均孔径为12.39552nm;孔容仅有0.041187cm³/g,试样多孔结构不明显,样本平均粒径为38.25μm。试样总的热失重率较小且随升温速率的影响变化规律不明显。4)实验获得最佳坯料配合比干基（wt%）为:污泥/粉煤灰/河道底泥=25%/15%/60%,最优化工艺参数分别为:预热温度350℃、焙烧终温1190℃、升温速率36K·min^-1、保温时间1min以及窑体旋转速率18π·min^-1;按照坯料配比和最优工艺参数开展烧制污泥陶粒放大实验研究,制得陶粒产品外观呈现浅棕褐色,产品圆润且颗粒大小相对均匀;测得焙烧流程烟道气体最高温度为306.75℃,烟道所含气体浓度极大值分别为:SO₂为30.07mg/m³,NO为17.93 mg/m³、NO₂为2.06mg/m³、CO为88.39mg/m³;均符合大气污染物综合排放标准（GB16297-1996）之污染物综合排放标准浓度限值规定。5)测试了陶粒产品的主要建材品质以及陶粒浸出毒性,结果显示陶粒产品可做建材用且产品符合环境安全性要求;实验试配陶粒混凝土强度等级LC30混凝土标准件,在室温20±2℃,相对湿度为95%以上的标准养护室中养护28天后的抗压强度为30.0MPa,符合LC30强度等级陶粒混凝土要求;干基混凝土试件的导热系数为0.75 W·（m*K）^-1保温隔热性能优异。6)配方坯料球试样总的热失重率随升温速率的增加而单调减小,DSC曲线峰值温度随升温速率的提高而单调升高,综合燃尽特性指数随升温速率提高单调减小,配方坯料球在空气氛围、不同升温速率下的热反应服从各主要热反应进程独立而平行开展的简单热反应机理模式,模拟TGA曲线准确描述实验TGA曲线变化趋势。陶粒产品主要的物相构成包括石英（SiO₂）、方石英（SiO₂）、蓝晶石（Al₂SiO₅）、高温钠长石（NaAlSi₃O₈）和类似多铝红柱石(Al₆Si₃O₁₃)的Al-Si-O结构等;重金属化合物（如铅、锰氧化物等）含量较少,其中石英是陶粒的主要物相构成。更多还原

【Abstract】 Sewage sludge is a by-product of wastewater treatment plant. It always contained pathogen and heavy metals, the longterm toxicity and non-degradable characters of sewage sldudge is threatening the disposal and further utilization of the sludge. How to properly treat and make use of sewage sludge is becoming a focus.In this case, many useful method such as XRD, FT-IR, laser-particle size analyzer, BET surface area, atomic absorption spectrophotometry, Thermogravimetry and differential scanning calorimetric analyzer were employed to study the physical, chemical and thermal characters of sewage sludge, PFA, river sludge and green pellets prepared by sewage sludge, PFA and river sludge. According to the most probable mechanism functions of thermal process, it took a quadratic polynomial nonlinear fitting method to simulate the TGA （thermogravimetry analysis） curves.In accordance with the orthogonal design method and the optimal raw materials chemical composition, it designed experiments to carry out optimal mixture ratio. It also used orthogonal design method to arrange experiments to find out the optimal of firing processing parameters, and discover the influence of processing parameters against variation regularity of the main performance of ceramisite.A pilot-scale experiment of producing sewage sludge ceramisite was carried out with the optimal mixture ratio and firing processing parameters. The flue gas generated in the firing process was analysed. The microstructure of ceramisite surveyed through SEM and EDS methods. In this study, main building characteristics were tested, and the application category of ceramisite discussed.Through the researches above, the findings as follows were obtained;1)The volatile solid of sewage sludge is at about 32.09%, the distribution of particle size submit Gaussian distribution, the particles between 39.9μm¹002.37μm were about 89.1% in the samples, the average particle diameter is 235.793μm; the BET surface area was small, and the vesicular structure was not obvious. The probably contained functional group were including hydrate, CO₃^2-, SiO₄^2-, -CH₃, R₂CH₂, amide C=O, benzene ring isomer, etc. The crystallinity of sewage sludge were low and sand grain could be seen in it. The main crystal phase of sewage sludge wasα-SiO2.2)According to the heating rates increasing, the maximum weightless speed rate and the corresponding conversion rate were monotone decreasing, the temperature of reaching maximum weightless speed rate point was monotone increasing. There were no regularities between the weightlessness and heating rate. The synthesis combustion characteristics of sewage sludge were monotone decreasing with the increasing heating rate. The thermal process of sewage sludge under atmosphere was following a simple thermal reaction mechanism that could describe as individual and paralleled carried out reactions. The numerical simulated TGA curves could describe the change characters of experimental TGA weightlessness well. The dry ash-free basis of sewage sludge possessed heat value was at about 23.25 MJ/kg, this indicated that the sewage sludge could self-support combust in some certain cases.3)The main constituent such as Si, Fe, Ca content of PFA used in this study was higher than the average level of PFA in China. The LOI, Al and Oxygen constituent of PFA was lower than the average level. The packing density of PFA was 835.24 kg/m³, the particle size distribution of PFA was following Gaussian distribution and the average particle size was 106.504μm. The BET surface area was 0.56m²/g, BJH average pore size was 7.4982nm, pore volume was 0.001027cm³/g and the vesicular structure was not obvious. There was one main weightlessness course of PFA under atmosphere and different heating rate.The oxide of river sludge was familiar with clay and the main chemical group was including carbonas and silicate. The BET surface area of river sludge was 13.0893m²/g, BJH average pore size was 12.39552nm, pore volume was 0.041187 cm³/g and the vesicular structure was not obvious. The average particle size was 38.25μm. The total weightlessness of river sludge is relative small. There were no regularities between total weightlessness and heating rate.4)Here came out the optimal mixture ratio of green pellets in dried basis （wt%） was sewage sludge/PFA/river sludge equal to 25%/15%/60% through experiments, and the optimal firing processing parameters were the pre-heat temperature 350℃, final temperature 1190℃, heating rate 36K?min-1, holding time 1 mins and the rotary speed 18π?min-1. In accordance with the optimal mixture ratio and firing processing parameters, a pilot-scale experiment carried out. The results showed that the ceramisites appearance was light brown and the shape was uniform. The maximum temperature of flue gas during the firing process was about 306.75℃, and the gas composition analyzed results could describe as following （maximum content）: SO2 was 30.07mg/m³, NO was 17.93mg/m³, NO2 was 2.06mg/m³ and CO was 88.39mg/m³. The results showed that the flue gas generated in firing process could fit the Chinese Integrated emission standard of air pollutants.5)The extraction toxicity and building material characters of ceramisite were tested, and the results showed that the ceramisite could be used as building materials, the ceramisite and its manufactures could fit environmental safety requirements. Try producing light concrete with ceramisite at the intensity level of LC30, by standard curing after 28 days to test the compression strength and coefficient of heat conductivity of the light concrete. The testing results showed that light concrete compression strength could fit the quality requirement of LC30 light concrete and coefficient of heat conductivity of the light concrete is significantly lower than normal concrete.6)The total weightlessness of pellets prepared by sewage sludge, PFA and river sludge was monotone decreasing with the increasing of heating rate. The DSC curves main peaks temperature was monotone rising with the increasing of heating rate, the synthesis combustion characteristics of pellets was monotone decreasing with the increasing of heating rate. The pellets thermal reactions under atmosphere with different heating rate could described as a simple thermal reaction mechanism that indicated the main thermal process submit individual and paralleled thermal mechanisms. The simulated TGA curves could discover the experimental TGA curves variation trend exactly. The main phase composition of ceramisite was including quartz （SiO2）, cristobalite （SiO2）, kyanite （Al2SiO5）, albite （NaAlSi3O8）, mullite （Al6Si3O13） and so on. The heavy metal compounds such as oxide of Pb and Mn were less, and quartz is the main phase composition in ceramisite.更多还原