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分析了电除尘器高频电源节能减排的机理,介绍了国内外高频电源的研究与应用情况,并指出其相对于传统工频电源的优越性。以上海外高桥第三发电有限责任公司8号炉的电除尘器改造为例,介绍了高频电源在1 000 MW燃煤机组电除尘器上的节能减排效果:在日常运行期间,改造后除尘器出口烟尘排放浓度由42 mg/m3下降至17 mg/m3,减排59.5%,电除尘器能耗降低71.7%。结合所选案例以及高频电源在其他电厂燃煤机组上成功应用的经验,分析了电除尘器高频电源对我国电力行业节能减排潜力:在2009年电力行业有关统计数据的基础上,若火电行业电除尘器全部进行高频电源改造,每年可节电31.5亿kW·h,相当于节约标准煤107.7万t,可减少120~210万t烟尘排放,1.07万t SO2排放,6 462~9 693 t NOx排放,310万t CO2排放。 相似文献
995.
Magdalna Pichlerov Jozef Výbook Dilek
nkal Kiki Ekiawan Lamatungga Dhanalakshmi Tamatam Lenka Marcinekov Viliam Pichler 《Ambio》2023,52(3):647
Public expectations of forests as high-quality restorative environments that facilitate subjective well-being and stress relief along with numerous health benefits have been rising sharply during recent decades. In addition, the COVID-19 pandemic and its accompanying restrictive measures also transformed forests into some of the few places to spend time away from home. The presented study drew on the assumption that the pandemic situation and a rise in the number of forest visits would affect the experience, recognition, and appreciation of the well-being aspects related to spending time in forests. The study goal was to elucidate the potential effects of the COVID-19 pandemic on the relationships between forest visits, well-being and stress relief, emotions, perception of nature and forest value and importance, pro-environmental behavior, and societal expectations of the role of forests and forest ecosystem services. A survey using a digital questionnaire was conducted several months after the pandemic outbreak on a representative sample of the Slovak population. The Wilcoxon test and ordinal regression analysis were used to identify significant relationships, e.g., between the recency of anger episodes and the number of forest visits. The results showed that the pandemic strengthened the perception of forests as a high-quality restorative environment and that emotions associated with forest visits played an important role in the perceived importance of forests and their possible overexploitation. The results underscore the urgent need to put demands for forest recreation on par with the forest bioeconomy and to sensitize forest visitors to management and conservation requirements. 相似文献
996.
Amenity values of private forests are implicit but play a critical role in decision and policy making. This study presents an innovative valuation approach integrating techniques of operations research and economic theory of pricing environmental goods. A forest planning problem was inversed through altering its reward function of timber values so that the observed harvesting behavior became optimal. The discrepancy between the original and new rewards uncovered amenities values which were linked to forest attributes via hedonic models. This method was applied to a case study of the U.S. southern pine region. Depending on forest conditions, total economic values of amenities varied from zero to just under one thousand dollar per ha. At a discount rate of 3%, a typically managed forest generated on average $243 ha−1 of amenities values per annum, more than twice of harvested timber values. Structural diversity and density of large pine trees were the key determinants to preserving forests for environmental amenities. 相似文献
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998.
公路隧道发生火灾开启横通道后,形成通风网络。本文以重庆地区吕家梁隧道为工程依托,进行了斜井前后不同位置发生火灾的通风网络模拟。结果表明,斜井前发生火灾时,受斜井浮力效应、风流密度变化等的影响,主风机的工作压力降低,而体积流量增加;当火灾发生在斜井前隧道时,采用斜井单抽方式可实现全部火灾烟流从竖井中排除,斜井前设射流风机增压调节、斜井后设射流风机增阻调节是一较好方案;对于斜井后发生火灾,采用全射流火灾通风和斜井压入两种通风方案均能满足火灾风流控制要求,虽然后者需要开启轴流风机,通风能耗大,但火灾通风的时效性要好于前者。 相似文献
999.
The root uptake of lead (Pb) by trees and the transfer of Pb by leaf litter deposition to the forest floor were investigated through a pot experiment with Norway spruce. Natural Pb and radio isotopic lead (210Pb) were determined in needles and twigs and in the pot soil spiked with 210Pb. Calculations of the specific activity in plant material and in the supporting pot soil showed that less than 2% of the Pb content of needles and twigs originates from root uptake and approximately 98% are deposited from the atmosphere. Atmospheric Pb has declined by a factor of 7 from 1980 to 2007 but is still a major pathway of Pb to vegetation and topsoils. The conclusion from the experiment is that the internal circulation of Pb through root uptake, translocation and litterfall, gives an insignificant input of Pb to the forest floor compared to atmospheric deposition. 相似文献
1000.
Manuela Baumgarten Christian Huber Patrick Büker Hans-Peter Dietrich Christian Heerdt Rainer Matyssek 《Environmental pollution (Barking, Essex : 1987)》2009,157(7):2091-2107
Exposure and flux-based indices of O3 risk were compared, at 19 forest locations across Bavaria in southern Germany from 2002 to 2005; leaf symptoms on mature beech trees found at these locations were also examined for O3 injury. O3 flux modelling was performed using continuously recorded O3 concentrations in combination with meteorological and soil moisture data collected from Level II forest sites. O3 measurements at nearby rural open-field sites proved appropriate as surrogates in cases where O3 data were lacking at forest sites (with altitude-dependent average differences of about 10% between O3 concentrations). Operational thresholds of biomass loss for both O3 indices were exceeded at the majority of the forest locations, suggesting similar risk under long-term average climate conditions. However, exposure-based indices estimated higher O3 risk during dry years as compared to the flux-based approach. In comparison, minor O3-like leaf injury symptoms were detected only at a few of the forest sites investigated. Relationships between flux-based risk thresholds and tree response need to be established for mature forest stands for validation of predicted growth reductions under the prevailing O3 regimes. 相似文献