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1.
介绍了长袋低压脉冲袋式除尘器的工作原理,比较客观详实的分析了在实际除尘过程中的前景及应用除尘效果。实践证明,袋式除尘器在水泥机立窑烟气除尘中适应性强,除尘效率可达99%以上,经济效益显著,是一种较理想的除尘设备.尤其适合在水泥行业中的应用。  相似文献   

2.
新疆油田公司供热公司为提高除尘效率,减少SO_2排放量,将多管除尘器改造为湿式除尘器,介绍了湿式除尘器的结构和除尘原理。针对存在的问题,通过改进溢流箱结构解决了水位控制问题,烟气含尘量和SO_2排放量均达到GB 13271—2001《锅炉大气污染物排放标准》。介绍了利用纯碱、电石渣、锅炉的冲渣水与除尘器流出的冲灰水混合这三种烟气脱硫方法,其中,锅炉的冲渣水与除尘器流出的冲灰水混合的烟气脱硫方法综合效果最好。  相似文献   

3.
袋式除尘器是一种高效除尘设备,它除尘的机理主要是过滤,用附着在滤袋上的一次尘,过滤二次尘。也就是说,用粉尘来过滤粉尘。国外也将袋式除尘器叫作过滤式除尘器。袋式除尘器的最大优点是除尘效率高,在实验室试验,除尘效率高达99.9999%,在实际应用中也达到了99.99%;每标准立方米排放浓度可达到2毫克,甚至卫毫克,这是袋式除尘的机理所决定的。袋式除尘器在实施污染物总量控制进行大气污染、粉尘污染、二氧化硫污染治理方面大有用武之地。我国的袋式除尘器,五十年代主要采用原苏联型式的产品。在国内开始有专业除尘…  相似文献   

4.
介绍了袋式除尘新技术在机立窑烟气治理中的应用,多台机立窑采用一台唧玻纤袋除尘器集中除尘,其技术已经非常成熟,可以说是机立窑玻纤袋除尘技术的重大突破,也是一次飞跃式的发展。文章对袋式除尘器的技术发展等做了论述。  相似文献   

5.
分析了电石法生产PVC项目危险废物产生的节点和产生方式,归纳了电石法PVC生产项目运行期间危险废物产生的重点类型、主要方式、关键节点及基本规律,为环境管理工作提供依据。  相似文献   

6.
近年来,电袋复合除尘技术在燃煤锅炉烟气除尘行业的应用取得了快速发展,并实现了600MW、1000MW大型机组的突破。电袋复合除尘器已成为继电除尘器、袋式除尘器之后的新一代高效除尘设备。应用实践表明,电袋复合除尘器对煤种变化的适应性强,可长期保持低排放,并具有运行阻力低、占地面积小等优点。介绍了世界上首台1000MW机组电袋复合除尘器的开发和应用情况。  相似文献   

7.
翟俊 《矿山环保》2003,(2):38-40
首钢矿业公司烧结厂结合自身生产特点,开展清洁生产工艺实践,应用了小球烧结、重油乳化、余热锅炉、除尘灰制粒等节能、低污染的清洁生产技术,将原低效除尘器全部改造成高效电除尘器,在生产全过程中有效预防、控制、削减污染物的产生量,既减少了环境污染,又提高了综合经济效益,形成有矿业烧结特色的清洁生产管理方法。  相似文献   

8.
旋转喷吹袋式除尘器结合了脉冲技术与常压反吹技术的优点,在含尘浓度高、风量大的烧结烟气治理行业中的应用较脉冲固定行喷吹袋式除尘器有着更为明显的优势。文章介绍了旋转喷吹除尘器的结构特点及其在实际工程中的应用。  相似文献   

9.
除尘脱硫一体化袋式除尘器   总被引:3,自引:0,他引:3  
火电厂和垃圾焚烧炉废气处理采用除尘脱硫一体化袋式除尘器,可简化工艺,减少系统阻力;已在国内的垃圾焚烧炉上应用。  相似文献   

10.
综述了我国袋式除尘技术的发展概况,重点分析了袋式除尘技术在水泥、钢铁、电力等行业的应用情况,详细介绍了袋式除尘器的专用纤维和滤料,以及袋式除尘器的配件等。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
ABSTRACT: Sustained interest in and concern about the health status of the aquatic environment has resulted in extensive research focused on (1) effects of pollution on survival, growth, and reproduction of resource species at all life stages; (2) diseases of fish and shellfish, as they may be related to pollution and as they may serve as indicators of environmental stress; and (3) contaminant body burdens in fish and shellfish - their effects on the aquatic animals and their potential effects on humans. Effects, lethal and sublethal, of pollutants on life history stages of fish and shellfish have been documented, as have impacts on local stocks in badly degraded habitats, but as yet there has been no adequate quantitative demonstration of effects on entire aquatic species - probably because of the difficulty in sorting out relative effects of the many environmental factors that influence abundance. Sublethal effects, especially those that result in disease, have been examined intensively, and some diseases and disease syndromes have been associated statistically with pollution. Other pollution indicators (biochemical, physiological, genetic, behavioral, and ecological) have also received some attention, as have body burdens of contaminants in aquatic species. Research, especially that conducted during the past decade, has done much to clarify the many pathways and toxic effects of contaminants on aquatic animals, and has also helped to identify mechanisms for survival of fish and shellfish in the presence of environmental changes caused by human activities.  相似文献   

14.
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.  相似文献   

15.
Urban ecological systems: scientific foundations and a decade of progress   总被引:9,自引:0,他引:9  
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.  相似文献   

16.
All major journalism ethical codes explicitly state that journalists should protect editorial copy from undue influence by outside sources. However, much of the previous research on agricultural information has concentrated on what information various media communicate (gatekeeping studies) or communication's role in increasing innovation adoption (diffusion studies). Few studies have concentrated specifically on organizational and structural constraints that might adversely affect agricultural journalists' ethical standards; those that have, focus largely on farm magazines. A study of newspaper reporters who cover agricultural news found that the most pressing ethical concern is the effect of advertiser (agri-business) pressure on editorial copy, and that their concerns in general parallel those of farm magazine writers and editors. The majority reported being in situations in which they might be exposed to advertiser pressure, including pressures to change or withhold editorial copy. Large minorities suggested that advertising pressures affect the overall environment in which agricultural journalists work, and more than one in ten said they allow advertiser pressures to influence editorial decisions. The newspaper reporters who cover agricultural beats showed slightly more resistance to advertiser pressure than did farm magazine editors in a parallel study.  相似文献   

17.
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.  相似文献   

18.
Mapped environmental classifications are defined using various procedures, but there has been little evaluation of the differences in their ability to discriminate variation in independent ecological characteristics. We tested the performance of environmental classifications of the streams and rivers of France that had been defined from the same environmental data using geographic regionalization and numerical classification of individual river valley segments. Test data comprised invertebrate assemblages, water chemistry, and hydrological indexes obtained from sites throughout France. Classification performance was measured by analysis of similarity (ANOSIM). Geometric regions defined by a regular grid and without regard to environmental variables and a posteriori classifications based on clustering the test datasets defined lower and upper bounds of performance for a given number of classes. Differences in classification performances were generally small. The ANOSIM statistics for the a posteriori classifications were around twice that of all environmental classifications, including geometrically defined regions. The hydro-ecoregions performed slightly better for the invertebrate data and the network classification performed slightly better for the chemistry and hydrological data. Our results indicate that environmental classifications that are defined using different procedures can be comparable in terms of their ability to discriminate variation of ecological characteristics and that alleged differences in performance arising from different classification procedures can be small relative to unexplained variation. We conclude that definition procedures might have little effect on the performance of large-scale environmental classifications and decisions over which procedures to use should be based primarily on pragmatic considerations.  相似文献   

19.
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.  相似文献   

20.
The maintenance of biodiversity is urged from many quarters and on grounds ranging from aesthetic considerations to its usefulness, particularly for biotechnology. But regardless of the grounds for preserving biodiversity, writers are generally in agreement that it should be preserved. But, in examining the various references biodiversity, such as species diversity, genetic diversity, and habitat diversity, it is apparent that we cannot aim to preserve biodiversityas such, since there are a number of conflicts in any such undertaking. In preserving one aspect of biodiversity, we damage another aspect. Five arguments which attempt to ground our moral concern for biodiversity are reviewed and critiqued, not only for their consistency but also for their power to move us to action. The final section of the paper shows how conflicts in the values of personal and environmental health can impair ethical action and especially policy formation.An earlier version of this paper was read at the conference on Agriculture, Food, and Human Values: Tradition and Change, Orlando, Florida, October 7–9, 1987.  相似文献   

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