燃煤锅炉烟气脱硝技术的研发与应用

选择性催化还原技术（SCR）是燃煤锅炉最有效的烟气脱硝技术，NH3／NOx混合效果是该技术工程设计时遇到的难点之一。QI^2-SCR技术在“主动利用不均”理念的指导下，开发了关于喷氨格栅的专利技术，充分发挥了有限体积催化剂的性能，在较小氨逃逸率的前提下，实现了较高的脱硝效率。     

烟气高效脱硝一体化技术的研究及应用

对某电力公司4号600MW机组烟气脱硝超低排放改造中,应用烟气高效脱硝一体化技术,采用特殊布置SCR反应器和高效催化剂,利用计算机流场分析优化烟道的设计、喷氨及混合装置,实现烟气脱硝的超低排放,同时控制飞灰、SO_3、氨逃逸等含量,避免对下游的脱硫、除尘设备产生不利影响而降低脱除效率。     

超低排放背景下煤电机组氨管控存在的问题及对策探析

近年来,我国大气污染防治成效显著,煤电机组超低排放政策实施对此做出了突出贡献。氮氧化物是煤电机组超低排放中的重要控制指标之一。然而,受现有氮氧化物排放监测和喷氨控制技术的精度、反馈时效等因素的限制,为提高脱硝效率保证性,电厂在实际运行中存在过量喷氨现象,未完全反应的氨进入大气后可能造成二次颗粒物增加。针对这一现象,本文回顾了我国火电行业氮氧化物排放标准和治理措施的演化及实施效果,对煤电机组氨排放现状和存在的问题进行了深入分析,提出在推进氮氧化物超低排放过程中应开展脱硝过量喷氨现状调研,鼓励企业开展脱硝系统优化,加强复杂烟气环境下氨监测技术研发,完善脱硝氨逃逸日常环境监管,推动氨排放全生命周期转化规律基础研究和大气环境效应评估,进一步提升煤电机组超低排放政策实施的综合环境效益,也对其他行业超低排放政策推进起到示范作用。     

“填料+丝网”除雾技术在石化电厂氨法脱硫的工业应用

采用“填料+丝网”除雾的氨法脱硫工艺技术解决氨法脱硫“烟气拖尾”及气溶胶等问题，并在克拉玛依石化公司热电厂进行应用实践。实际的脱硫效率达到了98%以上，出口烟尘尘小于10mg/m3。     

尿素催化水解精准喷氨联合技术在燃煤锅炉脱硝领域的应用

尿素催化水解技术是在普通尿素水解技术的基础上衍生出的改进技术,具有安全、稳定、灵活、经济等优点,结合CFD模拟、分区控制,实现精准喷氨,克服了常规技术的缺点,结果表明,这种联合技术效果良好,有广阔的发展前景.     

骑行新安江：沉醉山水画廊

一年一度的“五一”小长假，照例要单车远游。在路上，我血脉喷张，却不能信马由缰，因为这一次我的身份是领队，而我仅有的队员天际同学是个“菜驴”。这次我选择了骑行新安江，三百公里的旅程，风景有“山水画廊”之灵秀，人文有“唐诗之路”之厚重，足够吸引眼球。     

水泥窑炉SNCR工艺主要运行参数控制

结合西安西京公司1200t/h生产线烟气脱硝技改工程总承包项目的设计及调试,介绍了SNCR工艺的运行特点,总结出还原剂、氨氮比、喷枪安装位置及数量、喷氨量等工艺参数的合理规范及控制方法。调试运行证明,在合理的设计范围内,其整体运行情况良好,系统的脱硝效率可达到国家环保要求。     

危险废物焚烧工艺急冷系统的研究应用

危险废物焚烧处置过程中会生成包含二噁英在内的有毒有害物质，必须对烟气进行严格的净化处理。目前，危险废物焚烧采用温度骤降方式（雾化液滴与高温烟气混合实现对气体污染物组分的急冷降温），以减少二噁英异相合成的时间。急冷控制是焚烧尾气净化的重要技术，在以往项目中经常出现急冷雾化不良、水/气压力调节反应迟缓、急冷过喷、急冷欠喷等问题，对项目的顺利验收与运营造成影响。文章通过分析危废焚烧处理的工艺特点、结合项目经验，对急冷系统的设计与控制进行了研究与完善。该设计研究结果已在后续项目中予以应用。     

V_2O_5-WO_3/TiO_2催化剂在玻璃窑SCR脱硝中的应用

氨气选择性催化还原(SCR)脱硝技术已成熟应用于玻璃窑炉脱硝工艺。文章介绍了SCR脱硝工艺的核心V_2O_5-WO_3/TiO_2蜂窝催化剂应用方案的设计要素,并列举了典型工程实例的设计方案,进行催化剂性能分析。设计要素包括催化剂节距的选择、体积用量及元件长度的计算、催化剂层数、模块布置和最低喷氨温度等。通过催化剂性能分析,得出结论:脱硝效率与烟气流量及入口NO_x浓度成反比,而与NH_3/NO_x摩尔比成正比,NH_3/NO_x摩尔比的增高会加大氨逃逸;在一定温度范围内,烟气温度与脱硝效率及SO_2/SO_3转化率均成正比;烟气流量的增大和催化剂化学使用时间的延长,导致了催化剂压降的升高。     

烟气脱硝反应器计算流体力学模拟研究

SCR烟气脱硝系统中的流场与喷氨格栅设计,是影响系统主要技术指标的关键环节,采用计算流体动力学模拟方法建立计算模型,对某企业的锅炉烟气脱硝反应器进行模拟研究和工程设计,实践证明,该计算流体动力学模型能够满足烟气脱硝工程设计的精度要求,计算结果对工程设计具有较好的指导意义,对同类工程也具有一定的参考价值。     

Conversion of temperate forests into heaths: Role of ecosystem disturbance and ericaceous plants

Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation.     

Urban ecological systems: scientific foundations and a decade of progress

Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs.     

Neighbourhood characteristics and urban gardens in the Toledo metropolitan area: staffing and voluntarism,food production,infrastructure, and sustainability practices

Urban gardens are important sources of sustenance for communities with limited access to food. Hence, this study focuses on food production in gardens in the Toledo metropolitan area in Northwest Ohio. We administered surveys to 150 garden managers from November 2014 to February 2015 in our attempt to better understand how neighbourhood racial composition and poverty levels are related to staffing and voluntarism, food production and distribution, the development of infrastructure, and the adoption of sustainability practices in urban gardens. The results from 30 gardens are presented in this paper. We used Geographic Information Systems to map the gardens and overlay the map with 2010 census data so that we could conduct demographic analyses of the neighbourhoods in which the gardens were located. Though the gardens were small – two acres or less – up to 46 varieties of food were grown in a single garden. Gardens also operated on small budgets. Food from the gardens was gifted or shared with friends, family, and neighbourhood residents. Gardens in predominantly minority neighbourhoods tended to have fewer institutional partners, less garden infrastructure, and had adopted fewer sustainable practices than gardens in predominantly White neighbourhoods. Nonetheless, residents of predominantly minority and high-poverty neighbourhoods participated in garden activities and influenced garden operations. Volunteering and staffing were racialised and gendered.     

Using Paleo Reconstructions to Improve Streamflow Forecast Lead Time in the Western United States

In water stressed regions, water managers are exploring new horizons that would help in long‐range streamflow forecasts. Oceanic‐atmospheric oscillations have been shown to influence streamflow variability. In this study, long‐lead time streamflow forecasts are made using a multiclass kernel‐based data‐driven support vector machine (SVM) model. The extended streamflow records based on tree ring reconstructions were used to provide a longer time series data. Reconstructed data were used from 1658 to 1952 and the instrumental record was used from 1953 to 2007. Reconstructions for oceanic‐atmospheric oscillations included the El Niño‐Southern Oscillation, Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation, and North Atlantic Oscillation. Streamflow forecasts using all four oscillations were made with one‐year to five‐year lead times for 21 gages in the western United States. This is the first study that uses both instrumental and reconstructed data of oscillations in SVM model to improve streamflow forecast lead time. SVM model was able to provide “satisfactory” to “very good” forecasts with one‐ to five‐year lead time for the selected gages. The use of all the oscillation indices helped in achieving better predictability compared to using individual oscillations. The SVM modeling results are better when compared with multiple linear regression model forecasts. The findings are statistical in nature and are expected to be useful for long‐term water resources planning and management.     

Predicting deer-vehicle collisions in an urban area

Collisions with deer and other large animals are increasing, and the resulting economic costs and risks to public safety have made mitigation measures a priority for both city and wildlife managers. We created landscape models to describe and predict deer-vehicle collision (DVCs) within the City of Edmonton, Alberta. Models based on roadside characteristics revealed that DVCs occurred frequently where roadside vegetation was both denser and more diverse, and that DVCs were more likely to occur when the groomed width of roadside right-of-ways was smaller. No DVCs occurred where the width of the vegetation-free or manicured roadside buffer was greater than 40 m. Landscape-based models showed that DVCs were more likely in more heterogeneous landscapes where road densities were lower and speed limits were higher, and where non-forested vegetation such as farmland was in closer proximity to larger tracts of forest. These models can help wildlife and transportation managers to identify locations of high collision frequency for mitigation. Modifying certain landscape and roadside habitats can be an effective way to reduce deer-vehicle collisions.     

AN APPLICATION RUNOFF MODEL STRATEGY FOR UNGAGED WATERSHEDS1

ABSTRACT: Mathematical models for predicting watershed surface flow responses are available, most of which are elaborate nonlinear numerical surface and channel flow models linked with infiltration models. Such models may be used to make predictions for ungaged areas, assuming an acceptable fitting of the model to the topography and roughness of the real system. For some application purposes, these models are impractical because of their complexity and expensive computer solutions. A procedure is developed that uses a complex model of an ungaged area to derive a simpler parametric nonlinear system model for repetitious simulation with input sequences. The predicted flow outputs are obtained with the simpler model at significant savings of money and time. The procedures for constructing a complex kinematic model of a 40 acre (161,880 m²) reference watershed and deriving the simpler system model are outlined. The results of predictions from both models are compared with a selected set of measured events, all having essentially the same initial conditions. Peak discharges ranged from 3 to 118 ft³/sec (0.085 to 3.34 m³/sec), which includes the largest event of record. The inherent limitations of lumped systems models are demonstrated, including the bias caused by their inability to model infiltration losses after rainfall ceases. Computer costs and times for the models were compared. The derived simple model has a cost advantage when repeated use of a model is required. Such an applications hydrologic model has an engineering tradeoff of reduced accuracy, and lumping bias, but is more economical for certain design purposes.     

MANGANESE CYCLE IN IMPOUNDMENT WATER

Manganese entering impounded water will undergo a cyclic transformation. Oxidation precipitates manganese from top waters. At the bottom of the lake, biological activity will render manganese soluble by both intracellular as well as extracellular activity. The study was made to demonstrate that biological reduction and transformation, organometallic complexation, together with the presence of carbon dioxide and the lowering of pH all have some effect on the solubility of manganese. Dissolved manganese may be brought back to top waters during the lake overturn and therefore deteriorates the water quality.     

Surface applied water treatment residuals affect bioavailable phosphorus losses in Florida sands

Water treatment residuals (WTR) can reduce runoff P loss and surface co-application of P-sources and WTR is a practical way of land applying the residuals. In a rainfall simulation study, we evaluated the effects of surface co-applied P-sources and an Al-WTR on runoff and leacheate bioavailable P (BAP) losses from a Florida sand. Four P-sources, namely poultry manure, Boca Raton biosolids (high water-soluble P), Pompano biosolids (moderate water-soluble P), and triple super phosphate (TSP) were surface applied at 56 and 224kgPha(-1) (by weight) to represent low and high soil P loads typical of P- and N-based amendments rates. The treatments further received surface applied WTR at 0 or 10gWTRkg(-1) soil. BAP loss masses were greater in leachate (16.4-536mg) than in runoff (0.91-46mg), but were reduced in runoff and leachate by surface applied WTR. Masses of total BAP lost in the presence of surface applied WTR were less than approximately 75% of BAP losses in the absence of WTR. Total BAP losses from each of the organic sources applied at N-based rates were not greater than P loss from TSP applied at a P-based rate. The BAP loss at the N-based rate of moderate water-soluble P-source (Pompano biosolids) was not greater than BAP losses at the P-based rates of other organic sources tested. The hazards of excess P from applying organic P-sources at N-based rates are not greater than observed at P-based rates of mineral fertilizer. Results suggest that management of the environmental P hazards associated with N-based rates of organic materials in Florida sands is possible by either applying P-sources with WTR or using a moderate water-soluble P-source.     

Sources and Transport of Phosphorus to Rivers in California and Adjacent States,U.S., as Determined by SPARROW Modeling

The SPARROW (SPAtially Referenced Regression on Watershed attributes) model was used to simulate annual phosphorus loads and concentrations in unmonitored stream reaches in California, U.S., and portions of Nevada and Oregon. The model was calibrated using de‐trended streamflow and phosphorus concentration data at 80 locations. The model explained 91% of the variability in loads and 51% of the variability in yields for a base year of 2002. Point sources, geological background, and cultivated land were significant sources. Variables used to explain delivery of phosphorus from land to water were precipitation and soil clay content. Aquatic loss of phosphorus was significant in streams of all sizes, with the greatest decay predicted in small‐ and intermediate‐sized streams. Geological sources, including volcanic rocks and shales, were the principal control on concentrations and loads in many regions. Some localized formations such as the Monterey shale of southern California are important sources of phosphorus and may contribute to elevated stream concentrations. Many of the larger point source facilities were located in downstream areas, near the ocean, and do not affect inland streams except for a few locations. Large areas of cultivated land result in phosphorus load increases, but do not necessarily increase the loads above those of geological background in some cases because of local hydrology, which limits the potential of phosphorus transport from land to streams.     

Animal Consciousness and Ethics in Asia and the Pacific

The interactions between humans, animals and the environment have shaped human values and ethics, not only the genes that we are made of. The animal rights movement challenges human beings to reconsider interactions between humans and other animals, and maybe connected to the environmental movement that begs us to recognize the fact that there are symbiotic relationships between humans and all other organisms. The first part of this paper looks at types of bioethics, the implications of autonomy and the value of being alive. Then the level of consciousness of these relationships are explored in survey results from Asia and the Pacific, especially in the 1993 International Bioethics Survey conducted in Australia, Hong Kong, India, Israel, Japan, New Zealand, The Philippines, Russia, Singapore and Thailand. Very few mentioned animal consciousness in the survey, but there were more biocentric comments in Australia and Japan; and more comments with the idea of harmony including humans in Thailand. Comparisons between questions and surveys will also be made, in an attempt to describe what people imagine animal consciousness to be, and whether this relates to human ethics of the relationships. This revised version was published online in July 2006 with corrections to the Cover Date.