燃煤电厂SCR烟气脱硝技术的研究

选择性催化还原(SCR)技术是目前燃煤电厂应用最多且最成熟的烟气脱硝技术.介绍了SCR烟气脱硝技术的化学反应机理、工艺流程等,重点对影响SCR法脱硝效率的多种因素进行了深入分析,并对SCR技术的未来研究方向进行了展望.     

SCR脱硝催化剂失活机理研究综述

在烟气脱硝系统中,选择性催化还原催化剂的中毒和再生是广泛关注的问题。从催化剂的烧结、As、Ca、碱金属中毒等方面阐述了SCR脱硝催化剂的失活机理。通过总结催化剂的各种失活机理,可以有针对性地根据锅炉特性、燃料特性以及飞灰的成分进行SCR脱硝系统的优化设计,制定防止选择性催化还原催化剂失活的措施,这对延长催化剂寿命,降低SCR脱硝系统的运行维护费用具有重要意义。     

SCR脱硝系统对锅炉设备的影响及对策

以绥中发电B厂的烟气脱硝工程为例,介绍了选择性催化还原（SCR）脱硝工艺,并对SCR脱硝系统对锅炉设备的影响进行了分析,提出了解决对策,为新建脱硝系统及脱硝装置改造提供借鉴。     

选择性催化还原烟气脱硝技术及其在我国的应用研究

详细介绍了发达国家大量使用的选择性催化还原(SCR)烟气脱硝技术的原理、工艺流程及应用实例，同时对我国火电厂烟气脱硝SCR技术的实施进行了探讨。     

SCR氨区的运行维护

液氨是选择性催化还原脱硝法（ SCR）工艺首选的脱硝反应剂,它属于危险化学品。氨区的安全运行是SCR系统安全运行的基础保障。从氨区的运行、维护、人员防护和事故处理等方面阐述了SCR系统运行维护中需要注意的一些关键点。     

SCR系统中板式和蜂巢式催化剂的选取

选择性催化氧化还原法(SCR)是当今国际上最为成熟、有效的烟气脱硝技术。催化剂作为SCR工艺流程中最重要的设备部件，对SCR工艺的效率起着决定性的作用。分析了2种脱硝催化剂的物理、化学特性，以及它的优缺点，为催化剂的选取提供参考。     

嵩屿电厂烟气SCR脱硝工艺及特点分析

介绍了厦门嵩屿电厂4×300MW燃煤机组烟气选择性催化还原法(SCR)脱硝工程所选用的工艺,分析了SCR脱硝系统的主要技术特点,为日益增多的同类型脱硝装置的工艺设计与设备选型提供一定的借鉴。     

选择性非催化还原烟气脱硝技术在流化床锅炉上应用的探讨

对选择性非催化还原（SNCR）烟气脱硝技术与选择性催化还原（SCR）烟气脱硝技术在流化床锅炉上应用的适应性进行了对比分析。分析结果显示,相对于SCR技术,SNCR技术更适于流化床锅炉,指出了SNCR技术在流化床锅炉上应用存在的问题,N2O难以去除。     

SO2/SO3对选择性催化还原烟气脱硝的影响研究

研究表明，燃料燃烧过程中不同的SO2/SO3转化率对选择性催化还原（ Selective Catalytic Reduction，SCR）烟气脱硝的最低运行温度影响大，温度变化幅度为10~15℃。对燃烧高硫煤锅炉的SCR烟气脱硝，应控制更低的SO2/SO3转化率；对燃烧低硫煤锅炉的SCR烟气脱硝，通过适当提高SO2/SO3转化率，最大催化剂用量可减少一半、烟气阻力降低一半，可大幅降低SCR烟气脱硝建设成本和运行成本。     

W火焰600MW超临界锅炉中SCR脱硝岛的设计要求

从分析W火焰炉燃烧机理入手,着重分析了选择性催化还原(SCR)脱硝原理、工艺流程、脱硝岛在W火焰炉上整体布置方案、催化剂及脱硝烟道优化设计对后续设备的影响.     

Forestry best management practices for timber harvesting and site preparation in the eastern United States: An overview of water quality and productivity research during the past 20 years (1982–2002)

Forestry Best Management Practices (BMPs) were developed to protect water quality. In the eastern US, those BMPs were often expanded to include maintenance of site productivity. Generally, BMPs recommend the use of pre-harvest planning and careful design for construction of roads and other activities that expose bare soil, minimizing trafficking and areas of bare soil, maintaining streamside management zones, ensuring rapid revegetation following harvesting, minimizing soil disturbance, and ameliorating severe trafficking with site preparation. This review of peer-reviewed research from the past 20 years examined the effects of forest harvesting and site preparation on water quality and site productivity in the eastern US. The review was subdivided into areas having relatively similar physiography and land management (New England, Lake States, Appalachian Plateau, Ridge and Valley, Blue Ridge, Piedmont, Atlantic Coastal Plain, Gulf Coastal Plain, and Ouachitas-Ozarks). In general, data from steeper physiographic regions indicated that forest harvesting and site preparation can increase erosion, sediment and nutrient losses to streams. However, the quantities introduced into streams tended to be relatively low, generally below the values that are considered acceptable for alternative land uses. Also most research indicated that water quality recovers within two to five years following forest operation disturbances, particularly if BMPs are employed. Research from the less mountainous and often more poorly drained Lake States and Coastal Plain regions indicated that soil compaction and rutting may or may not cause site productivity effects, depending on soil types, natural ameliorative properties and site preparation. Overall, the research supports the forestry BMPs recommended in the eastern states.     

Bioassessment of silvicultural impacts in streams and wetlands of the Eastern United States

Bioassessment is a useful tool to determine the impact of logging practices on the biological integrity of streams and wetlands. Measuring biota directly has an intuitive appeal for impact assessment, and biota can be superior indicators to physical or chemical characteristics because they can reflect cumulative impacts over time. Logging can affect stream and wetland biota by increasing sedimentation rates, altering hydrologic, thermal, and chemical regimes, and changing the base of food webs. Biotic impacts of logging on streams compared to wetlands probably differ, and in this paper we review some of those differences. In streams, invertebrates, fishes, amphibians, algae, and macrophytes have been used as indicators of logging impacts. In wetlands, bioassessment is just beginning to be used, and plants and birds are the most promising indicator taxa. Various best management practices (BMPs) have been developed to reduce the impacts of logging on stream and wetland biota, and we review quantitative studies that have evaluated the efficacy of some of these techniques in streams and wetlands in the eastern United States. Remarkably few studies that address the overall efficacy of BMPs in limiting biotic changes in streams and wetlands after BMP implementation have been published in scientific journals, although some work exists in reports or is unpublished. We review these works, and compile conclusions about BMP efficacy for biota from this body of research.     

Bisolute Equilibrium Studies for the Sorption of Basic Dyes on a GAC from Almond Shells: A Nonlinear Approach

Aqueous phase adsorption of three textile dyes onto a granular activated carbon produced from acid activation of almond shells is presented. Primarily, the sorption of three basic dyes, methylene blue, rhodamine b, and malachite green oxalate were studied. Four models, the Freundlich, the Langmuir, the Redlich-Peterson, and the Toth isotherms were compared for their quality of fit to the single-solute sorption data. Next, sorption of the three likely binary systems was examined. Four bi-solute models, the extended Langmuir with and without an interaction term, the extended Redlich-Peterson with an interaction term, and the empirical extended Freundlich model were used to predict sorption in the binary systems. Nonlinearly determined constants of the corresponding single-solute isotherms were used in the binary models to compare with experimental binary sorption data. For the single-solute system, the three-parameter models of the Redlich-Peterson and the Toth isotherms outperformed the Langmuir and Freundlich models. The empirical extended Freundlich model produced the closest comparison to the binary data in each system. In general, the nonlinear method provided a simple and computationally effective technique of producing optimal fitting parameters for the bi-solute sorption models.     

百菌清污染土壤生物修复研究进展

针对百菌清具有在土壤中药效稳定、不易分解、代谢周期长、长期大量施加导致土壤严重污染等特点和问题,简要介绍了百菌清的毒性作用机制。总结了降解土壤中百菌清的物理法、化学法和生物法的原理及优缺点。重点阐述了生物修复百菌清污染土壤的主要降解菌株及其效果、降解途径以及降解产物及其毒性,分析了土壤性质、微生物种类、温度、土壤含水率等因素对百菌清降解效果的影响。指出今后的研究重点应为降解中间产物的毒性分析及其进一步的降解与转化问题,而复合菌制剂或多酶复合体系可实现百菌清的彻底降解和无害化。     

炼厂浮渣的超声强化脱水处理

针对炼厂浮渣乳化严重、脱水减量困难的问题,采用超声—离心分离工艺对其进行强化脱水处理。比较了单独离心、絮凝—离心和超声—离心3种方式对浮渣的脱水效果,考察了超声时间和超声温度对浮渣脱水效果的影响,表征了超声处理前后浮渣的微观结构,探讨了超声强化脱水的机理。实验结果表明:在未加任何药剂、超声频率25 kHz、超声功率240 W、超声时间5 min、超声温度30℃的最佳工艺条件下,浮渣脱水率为89.68%,较单独离心和絮凝—离心工艺分别提高了7.77和2.99百分点,底泥含水率为82.94%。表征结果显示:超声机械振动作用破坏了固体颗粒空隙和内部沟壑结构,降低了对油滴的吸附,促进了油滴凝并,实现了原油轻质化,说明超声作用可促进浮渣脱水。     

Solubility and Potential Mobility of Heavy Metals in Two Contaminated Urban Soils from Stockholm,Sweden

The solubility and potential mobility of heavy metals (Cd, Cu,Hg, Pb and Zn) in two urban soils were studied by sequential andleaching extractions (rainwater). Compared to rural (arable) soils on similar parent material, the urban soils were highlycontaminated with Hg and Pb and to a lesser extent also with Cd,Cu and Zn. Metal concentrations in rainwater leachates were related to sequential extractions and metal levels reported fromStockholm groundwater. Cadmium and Zn in the soils were mainly recovered in easily extractable fractions, whereas Cu and Pb were complex bound. Concentrations of Pb in the residual fractionwere between two- and eightfold those in arable soils, indicatingthat the sequential extraction scheme did not reflect the solidphases affected by anthropogenic inputs. Cadmium and Zn conc. inthe rainwater leachates were within the range detected in Stockholm groundwater, while Cu and Pb conc. were higher, whichsuggests that Cu and Pb released from the surface soil were immobilised in deeper soil layers. In a soil highly contaminatedwith Hg, the Hg conc. in the leachate was above the median concentration, but still 50 times lower than the max concentration found in groundwater, indicating the possibilityof other sources. In conclusion, it proved difficult to quantitatively predict the mobility of metals in soils by sequential extractions.     

Urban Metal Flows – A Case Study of Stockholm. Review and Conclusions

Metals have rapidly accumulated in the anthroposphere, especiallyin urban areas, indicating possible environmental and resource problems. Here, Stockholm City was chosen for a case study of urban metal flows, i.e. metal inflow to, metals in the stock of,and metal outflow from the anthroposphere to the biosphere. Themetal stock of Stockholm is large and still growing. The large amounts of metals in the solid waste fraction totally dominatethe outflow from the city. For major parts of the stock, the emissions from goods in use are negligible. There are, however,goods applications corresponding to significant emissions: e.g. the traffic sector (Cu, Zn, Cr, Ni, Pb), the tapwater system (Cu), roofs/fronts or other metal surfaces (Cu, Zn). Today's known metal flows from the anthroposphere of Stockholm to the biosphere and sewage sludge are quantitatively dominated by Zn(34 ton y^-1) and Cu (14 ton y^-1). Historical and present emissions have resulted in high metal concentrations insediments (especially Cd, Hg and Pb, but also Cu and Zn), groundwater (Cu, Hg) and in soils (Hg, Cu, Pb). At present theannual median concentrations are below the Swedish limits for metals in sewage sludge, even if the safety margins aresmall for Cd, Hg and to some extent Cu. The flows of Cu and Zn to Stockholm soils are high with a significant accumulationindicating an environmental impact in a longer time perspective.High levels of metals in surface sediments in the waterenvironments reflects an ongoing input where these metals aretransported from known (Cu, Zn) and or partly unknown (Cd, Hg, Pb) sources. In future urban areas, monitoring of metal flows must be performed both in the anthroposphere and the biospherein order to have a pro active approach to urban environmentalproblems and to get prompt answers to measures taken.     

人工湿地构造及生物因素研究进展

介绍了近10年报道的不同构造人工湿地(CW)的污水处理性能及CW中微生物、植物、动物的相关研究进展.分析了各种CW构造优缺点、CW与其他技术的结合、CW微生物群落的特征、影响因素和研究手段、CW植物与动物对CW处理性能的贡献及作用机制.提出今后应重点研究:复合人工湿地(ICW)工艺优化;CW强化技术及其参数;CW微生物...     

Heavy Metal Sediment Load from the City of Stockholm

A transect of upstream lake sitesand downstream coastal sites surrounding the cityof Stockholm, capital of Sweden, wereinvestigated for heavy metals in sediments.Concentrations of Cd, Cu, Hg, Pb and Zn increasedclose to the city. In the most central areas ofStockholm, sediment deposition was increasedabout 5-fold for Cd, Cu, Hg and Pb and 3-fold forZn, as compared to the surrounding areas. Thesediment load from the city was estimated bycorrecting for a background concentration. It canbe concluded that most of the load of Hg and Pbwas trapped in the sediments close to the citywhile Ni, Cu, Cd and Zn to a higher degree weretransported through the archipelago towards theBaltic Sea.     

超声协同Fenton法处理有机废水的研究进展

超声协同Fenton法是利用超声的空化效应及自由基效应强化Fenton法对废水的处理效率,实现两者对废水中有机污染物的协同降解。概述了超声与Fenton法处理废水的协同机制。综述了废水pH、催化剂和H₂O₂投加量、超声功率、温度等工艺条件的优化研究,催化剂的研发以及共存物质的影响研究等方面的进展。指出开发新型高效、可重复利用、廉价易得的催化剂是提高超声协同Fenton法降解有机污染物效率的关键,还可将超声、Fenton法或超声协同Fenton法与其他的氧化法或生化方法相结合,寻找更加安全、高效、低成本的新途径。