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从流化床锅炉的旋风分离器出口烟道抽取高温烟气进行污泥干化,干化后的污泥与煤掺烧,是污泥处置方法之一.为掌握这种污泥干化掺烧系统的性能,通过热平衡计算分析了污泥掺烧比例和干化污泥含水率对烟气量、燃烧温度、受热面吸热量分配比例、抽取热烟比例、燃煤量的影响.结果表明:污泥掺烧会降低理论燃烧温度,增加炉内总烟气量.随着污泥干化程度和掺烧比例的升高,污泥干化所需抽热烟气的比例、炉膛和尾部烟道中受热面吸热量的比例都会增大;过大的污泥掺烧比例会导致炉膛尺寸显著大于尾部烟道,给锅炉设计带来困难.污泥干化程度和掺烧比例对节煤量的影响很小,污泥干化不能直接产生显著的节能效果;优选干化污泥含水率和掺烧比,其作用在于控制炉内烟气量和温度水平,优化焚烧炉和干化设备的配置,降低总投资成本. 相似文献
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《热能动力工程》2016,31(9)
本文介绍了污泥的基本特性,对直接热干化、间接热干化、直接-间接联合热干化和其它污泥干化技术的工作原理和优缺点进行了比较,重点讨论单独焚烧、电站锅炉掺烧、垃圾焚烧炉掺烧和水泥窑掺烧等污泥焚烧技术的工艺路线、应用情况和技术特点。分析可知,污泥干化焚烧技术类型多样,采用烟气或蒸汽对污泥进行干化都是可行的,干化污泥单独焚烧、电站锅炉掺烧或者水泥窑协同处置等都有成功案例,应根据具体条件选择合适的工艺,其中将污泥干化后利用流化床焚烧炉进行单独焚烧或在电站锅炉上进行掺烧是最具应用前景的技术路线,而污泥输送、高效干化技术与设备开发及厂区臭气治理等是有待进一步研究的问题。 相似文献
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为了得到燃煤电厂掺烧生活污泥燃烧及环保特性规律,基于国内某电厂的330 MW亚临界四角切圆燃煤锅炉,针对6个工况开展现场试验研究。结果表明:燃煤、污泥与混合后的燃料在成分含量上区别较大;掺烧污泥会导致锅炉燃烧温度与热效率降低,最大的降幅分别为28℃和0.19%,总体降幅较小;掺烧污泥后,飞灰与炉渣中重金属含量及氯含量稍微上升,不会明显提高结渣风险;掺烧污泥后,现有的净化工艺仍能确保常规烟气污染物的排放浓度能满足燃煤烟气超低排放要求;随着掺烧比例的提高,NOx的排放量呈现先增加后降低的趋势,SO2的排放量逐渐降低,粉尘颗粒的排放量稍微提高;掺烧污泥不会对二噁英类和重金属及其化合物等非常规烟气污染物造成明显影响,排放情况能够满足燃煤电厂限制要求;风烟系统各级风机用电量普遍随着掺烧污泥量增加而提升,最大的提升幅度为5.4A,适当调整后均能够正常运行。 相似文献
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为了有效处理产量日益增加的污水处理厂污泥,减少其对环境的二次污染,将污泥干化后与煤粉在锅炉中混燃是被公认为较佳的方式。然而在现场试验中由于污泥物性与煤粉的差别会对实际的锅炉运作带来很多影响。了解污泥掺烧对锅炉带来的影响,将会为污泥在煤粉炉中的掺烧提供指导作用。 相似文献
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以上海某污水处理厂为例,通过理论计算和工程设计分析,研究了入炉污泥含水率(质量分数)对污泥干化焚烧工艺的影响.结果表明,随着干化程度的提高,对干燥机处理能力的要求提高,对干燥机型式的选择余地缩小,对焚烧炉、余热锅炉等设备的要求也将提高,对设备材质、系统安装、运行管理的要求也将相应提高.随着污泥干化程度的降低,进料量和烟气量增大,导致焚烧和烟气处理设备体积庞大.由于污泥泥质特性随时间变化大,在污泥热值整体偏低的地区,采用60%入炉污泥含水率存在一定的风险.污泥入炉含水率对污泥焚烧处理工程中的工艺选择及布置影响较大,工程设计中不应简单照搬国内外类似工程,而应根据当地污泥泥质特性、热值、辅助热源等实际情况,合理选择入炉污泥含水率. 相似文献
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A boiler plant is presented, in which the fuel is dried before combustion in a silo with air. The drying air is heated in a recuperative heat exchanger by the heat of flue gases. Hot air is then blown through the bed of fuel in the drying silo, while the fuel dries and the air cools down and becomes humidified. Heat of the moist exhaust air of the silo is recovered for the drying air and combustion air by a recuperative heat exchanger. Modelling of the thermal behaviour of the plant helps in understanding complex interdependencies of the two heat exchangers, the boiler and the dryer. The models of the heat exchangers and applications in analysing the boiler system are described in this paper. Calculating the combinations of extreme operational conditions gives the input data needed in comparing different types of heat exchangers, dimensioning the heat transfer area, choosing the control strategy and selecting the operating parameters and set‐values of the control system. Results of verification measurements and practical operation at a 40 kWth pilot plant and a 500 kWth demonstration plant are also discussed. Using engineering correlation formulas for heat and mass transfer, an adequate accuracy between the model and the measurements was achieved. Fouling was detected to be a major problem with the flue gas heat exchanger. However, in absence of condensation, the increase of a fouling layer with respect to time was observed to be low. Fouling was also a problem with the drying exhaust gas heat exchanger, but after the installation of a simple dust collector, a reasonable cleaning period was achieved. A mixed‐flow configuration was found to be the most appropriate for the flue gas heat exchanger. In order to avoid condensation of the flue gas the drying exhaust gas heat exchanger is indispensable in Finnish climate in the considered system. In addition to this, it decreases the need of fuel. A parallel‐flow type was found the most appropriate as the drying exhaust gas heat exchanger. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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The objective of this work is to survey the fate of potassium in the gas phase of a fluidised bed boiler and gain deeper understanding of the involved mechanisms during co-firing of municipal sewage sludge with biomass containing high amounts of potassium and chlorine. The results show that formation of alkali chlorides in the flue gas and corrosive deposits on heat transfer surfaces can be controlled by addition of municipal sewage sludge even though the fuel is highly contaminated with chlorine. The beneficial effects are partly due to the content of sulphur in the sludge, partly to the properties of the sludge ash. The sludge ash consists of both crystalline and amorphous phases. It contains silica, aluminium, calcium, iron and phosphorus which all are involved in the capture of potassium. 相似文献