| 题名 | 城市污泥燃料化利用的相关研究 |
| 作者 | 王娟 |
| 学位类别 | 硕士 |
| 答辩日期 | 2012-04-01 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 潘峰 ; 刘会洲 |
| 关键词 | 垃圾衍生燃料 污泥燃料 干化 燃烧产物 |
| 其他题名 | Study on Fuel-oriented Utilization of Municipal Sludge |
| 学位专业 | 化学工艺 |
| 中文摘要 | 污泥是污水处理过程产生的二次产物，它是一种介于固体和液体之间的混合物，很难进行固液分离。随着社会和经济的发展，全国各城市加大了对污水处理的投入，污泥的产量也逐渐增多，由此带来的环境污染问题越来越被关注，如何有效的处置污泥成为了环保界关注的焦点。由于污泥本身的性质比较复杂，如果不妥善处置，会造成严重的二次污染。传统的污泥处置方式如填埋、堆肥、焚烧、投海等各有自身的缺点，使得污泥的处置逐渐寻求新的方式。近年来，垃圾衍生燃料（RDF）技术在处置固体垃圾方面取得了较好的成果。本论文将垃圾衍生燃料技术应用于污泥的处置，研究了污泥的基本性质和脱水干化的最佳条件，以及污泥燃烧过程中产生的污染排放物的特性和控制方法，并对污泥作为燃料利用的经济可行性进行了分析。 将污泥的基本性质进行分析并研究了污泥在脱水干化过程中含水率、热值等的变化情况，探寻了污泥干化的最佳时间和温度，考察了污泥与煤的一些基本性质以及污泥与煤混和燃烧的特性。结果表明，污泥在不同温度下干化4 h后，含水率降到10%以下，并且趋于稳定值；发热量在干化4 h后均达到18 MJ/kg，继续延长加热时间，发热量不变。通过将污泥在105和150℃下分别干化，发现污泥中可燃的有效成分基本没有发生变化，发热量变化较小，只是高温条件下干化，污泥颗粒表面变得更加粗糙，并且有鳞片状物质生成。污泥与煤粉具有不同的形貌结构和燃烧过程。前者形状不规则，颗粒松散粗糙，并且有较多的孔结构；而后者有较规则的形状，固体颗粒致密，表面光滑，没有孔结构。这也是污泥比煤容易燃烧，而煤比污泥耐烧的原因；污泥燃烧过程中主要以挥发分燃烧为主，而煤的燃烧过程中，固定碳的燃烧起主要作用。 分析污泥在微型流化床中燃烧情况，研究了污泥燃烧过程中污染气体的排放特性，并考察了加入添加剂后污泥燃烧排放气体的变化规律。结果表明，污泥在燃烧过程中不同的气体产生的时间几乎是同时的，这主要是因为反应是在900℃的高温下进行的，样品升温速率较快，瞬间燃烧，因此反应物质中各种组分热分解的难易程度几乎没有差别，所以气体释放时间上比较接近。实验选取氧化钙为添加剂来抑制污泥燃烧过程中污染气体的排放，结果发现，在添加氧化钙的比例为 nCa:nS=2:1和nCa:nS=4:1（物质的量之比）时，二氧化硫和氮氧化物的浓度均有所降低。添加剂氧化钙由于不能进行燃烧，所以在加入到污泥中时，使得污泥的热值有所降低。 将污泥燃烧灰渣中的重金属及灰渣形貌特征进行了研究，并对污泥质燃料的经济可行性进行了分析。结果表明，污泥燃烧灰渣中重金属含量较高，但是浸出毒性实验中重金属含量未超标。污泥灰渣的结构比煤松散，且表面有较多的孔结构，因此可以利用灰渣的这种结构将其制成吸附剂，用来吸附有机物和重金属。通过应用费用—效益的方法来评价污泥质燃料的生产情况得出，生产污泥质燃料在10年内的净效益是大于0的，说明此项目是可行的。 |
| 英文摘要 | The sewage sludge is the second product of waste water treatment. It is difficult to separate the solid from liquid. With the development of economic and society, many cities have increased the investment on the disposal of sewage in our country. The increasing of sewage sludge production has brought about environmental threats, which has aroused a wide public concern. How to dispose of the municipal sewage sludge is growing the focus of attention concern in the field of environment protection. Sludge has complex features, if it is not treated properly, the sludge will cause serious second pollution. The traditional disposal methods, for example, landfill, fertilization, incineration, oceanic jettison, have many shortcomings, so the disposal of sludge needs new ways. Recently, RDF(Refuse Derived Fuel) technology has been applied in the field of treatment of solid waste. In this paper, RDF technology was used in the disposal of sewage sludge, the properties of sludge and the best conditions of dehydration were studied, the pollution emission characteristics of sludge and the control methods were investigated, and the economic feasibility of RDF was also analyzed. The intrinsic properties of the sludge were studied, variations of moisture content and calorific value during the dehydration were measured, and analyzed for achieving the optimal drying conditions of sludge and the effect of proportion of adding pulverized coal playing in the combustion of sludge. The results showed that the optimal drying time was 4 h and the heating value of dried sludge was 18 MJ/kg, and the change of heating value of the sludge was the result of changes in water content and organic content. Besides, the effective ingredients of sludge almost had no change when the drying temperatures varied from 105 to 150℃, but the surface of the sludge became coarse after dried at 150℃. The sludge and coal have different structural features and burning process, the former has irregular shape, its particle are loose coarse, with porous structure; and the latter has regular shape and smooth surface, without porous structure, which is the reason why coal burning resistance than sludge. In addition, the sludge was burnt basically in the form of volatile matters, which is different from coal that combusted mainly based on fixed carbon. Micro fluidized bed was applied to sludge combustion, the pollution emission characteristics of sludge combustion and variation of sludge combustion emission gas after adding additives. The results indicated that different combustion gases release at the same time during the sludge combustion, because the combustion occurred at a temperature as high as 900℃, so the difficulty of material components thermal decomposition has almost no difference. CaO was selected as additive to control pollution emissions during sludge combustion, when the mole ratio of additive ratio is nCa:nS=2:1 and nCa:nS=4:1, the concentration of SO2, NOX emission has decreased , when the sludge was used for combustion experiment. Because the additives are not combustible, so the heating value of sludge mixed with additives is reduced. The heavy metals and morphological characteristics of sludge combusted ash were investigated, and the economic feasibility of sludge fuel was also analyzed. The results indicated that the content of heavy metals in sludge ash is very high, but the content of heavy metal in leaching solution does not exceed limit. The structure of sludge ash is looser than coal ash, and the surface of sludge ash is porous, so it can be made into adsorbent to adsorb organic matters and heavy metals. Cost-benefit analysis method was applied to analyze economic feasibility of production technology of sludge fuel, the results showed that the benefit of sludge fuel is positive, so the project of application is feasible. |
| 语种 | 中文 |
| 公开日期 | 2014-05-23 |
| 页码 | 75 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/8307]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 王娟. 城市污泥燃料化利用的相关研究[D]. 中国科学院研究生院. 2012. |
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