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结合燃煤电厂电袋复合除尘器的入口烟道气流分布的工程案例,采用计算流体动力学(简称CFD)数值模拟技术,对烟道内的速度场进行三维数值模拟;根据分析结果进行烟道的导流板的设置,改善烟道的流场,并使入口烟道的各分支烟道流量分配均匀。对比现场烟道流量分配的测试结果,验证了CFD模拟计算的准确性。 相似文献
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《中国环保产业》2019,(8)
由于部分火电厂燃煤锅炉采用低氮改造+SNCR或SCR脱硝技术的氮氧化物排放浓度达不到现行超低排放标准,因此就必须采用脱硝效率更高的SCR脱硝技术对原有系统进行改造,由于SCR对烟气温度的要求和厂区场地限制,SCR脱硝系统烟气的引出和接入位置空间狭小(2~4m),进出烟道甚至要共用烟道壁板,这样就产生烟气偏流和烟道内积灰现象。文章首先以某燃煤锅炉烟气脱硝工程的直角弯头改造为研究对象,采用FLUENT数值模拟方法研究直角弯头烟气的流动分布,在此基础上,对导流板进行优化设计,直角弯头在改造前积灰严重,影响锅炉工况,经改造后积灰状况得到极大改善,保证了系统正常运行。 相似文献
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烟尘的测定,通常是用采样管从烟道中抽取一定体积的烟气,通过捕集装置捕集尘粒,然后根据捕集的尘粒量和抽取的烟气量,求出烟尘浓度.根据烟尘浓度和烟气的流量计算其排放量.为了从烟道中取得有代表性的烟尘样品,需等速采样,即气体进入采样嘴的速度应与采样点的烟气速度相等.这样,样品浓度才与实际浓度相等.采样速度若大于或小于采样点的烟气速度都将使采样结果产生偏差.烟气压力参数的测定直接影响烟尘测定结果的准确性.根据《空气和废气监测分析方法》,烟尘采样有预测流速法、平行采样法和压力平衡法,三种方法中,常用压力平衡法,此法又分动压平衡法和静压平衡法,动压平衡法是利用装置在采样管上的孔板差压与皮托管指示的测点烟气动压相平衡来实现等速采样.动压平衡法的优点是不需要预先测出烟气流速和烟气状态参数和计算等速采样流量,而是通过调节动压达到平衡即可进行等速采样,不但操作简单,并且能跟踪烟气速度变化而随时保持等速条件,提高等速精度.但是,笔者运用此法测定烟尘多年,发现还有不足和局限性. 相似文献
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电解槽密闭排烟系统包括排烟管道( 含水平烟道及支烟管) ,槽盖板及集气罩。目前集气罩内部阻力过大,造成对烟气吸抽量过小。改进的方法是:①水平烟道通过测试得出单台槽的负压变化量,调节支烟管蝶阀的开启角度平衡烟道负压;②进一步提高槽盖板完好率、盖放率及槽盖板的制作安装精度,以达到提高集气效率的目的。 相似文献
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苏州市环保局在市中级人民法院的支持、帮助下,建立环境污染纠纷调解、仲裁组织,依照仲裁程序对一些环境污染纠纷进行了调解和仲裁,有效她调整了矛盾双方的关系,维护了国家、集体、个人的利益,有力地推动了工矿企业对于污染源的治理。下面列举几个用仲裁方式解决环境污染纠纷的案例: (一) 苏州市柳巷17号居民陈长乐在一九八一年十月十四日正式向苏州市环境保护局提出申诉:被告苏州乳胶厂因锅炉烟道紧贴原告的墙壁,由于烟道散热和烟道壁(包括墙壁)裂缝,使原告紧靠烟道的一间住房(约13.5m~2),室内温度升高,空气受 相似文献
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Richard D. Horan Marc O. Ribaudo 《Journal of the American Water Resources Association》1999,35(5):1023-1035
In this paper, we review the physical characteristics of agricultural non point pollution and discuss the implications for setting appropriate pollution control objectives and designing incentive-based pollution control policies. First, we discuss that policy objectives must be designed carefully to ensure positive economic net benefits can be expected from pollution control. Next, we review several classes of incentives and recommend the use of design-based incentives (i.e., incentives based on variable input use, management practices, and land use) for controlling non point pollution. Cost-effectiveness requires that incentives elicit three types of responses from farmers: (1) use variable inputs at appropriate levels, (2) adopt appropriate management practices, and (3) make appropriate land use decisions at the extensive margin of production. If a set of incentives fails to induce the correct responses, the resulting runoff levels and hence ambient pollution levels and damages will be too large relative to policy goals. A review of existing programs suggests that greater program coordination and improved targeting of incentives are needed for further water quality improvements. Alternatively, properly designed market-based systems may be effective alternatives. These systems would reduce overall pollution control costs by allowing markets to allocate point source and non point source control costs more efficiently. 相似文献
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Sheryl Luzzadder-Beach 《Environmental management》1995,19(3):383-392
What size sample is sufficient for spatially sampling ambient groundwater quality? Water quality data are only as spatially accurate as the geographic sampling strategies used to collect them. This research used sequential sampling and regression analysis to evaluate groundwater quality spatial sampling policy changes proposed by California's Department of Water Resources. Iterative or sequential sampling of a hypothetical groundwater basin's water quality produced data sets from sample sizes ranging from 2.8% to 95% coverage of available point sample sites. Contour maps based on these sample data sets were compared to an original (control), mapped hypothetical data set, to determine at which point map information content and pattern portrayal are not improved by increasing sample sizes. Comparing series of contour maps of ground water quality concentration is a common means of evaluating the geographic extent of groundwater quality change. Comparisons included visual inspection of contout maps and statistical tests on digital versions of these map files, including correlation and regression products. This research demonstrated that, down to about 15% sample site coverage, there is no difference between contour maps produced from the different sampling strategies and the contout map of the original data set. 相似文献
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Anthony R. Prestigiacomo Steven W. Effler Rakesh K. Gelda David A. Matthews Martin T. Auer Benjamin E. Downer Anika Kuczynski M. Todd Walter 《Journal of the American Water Resources Association》2016,52(1):31-47
The integration of the phosphorus (P) bioavailability concept into a P loading analysis for Cayuga Lake, New York, is documented. Components of the analyses included the: (1) monitoring of particulate P (PP), soluble unreactive P (SUP), and soluble reactive P (SRP), supported by biweekly and runoff event‐based sampling of the lake's four largest tributaries; (2) development of relationships between tributary P concentrations and flow; (3) algal bioavailability assays of PP, SUP, and SRP from primary tributaries and the three largest point sources; and (4) development of P loading estimates to apportion contributions according to individual nonpoint and point sources, and to represent the effects of interannual variations in tributary flows on P loads. Tributary SRP, SUP, and PP are demonstrated to be completely, mostly, and less bioavailable, respectively. The highest mean bioavailability for PP was observed for the stream with the highest agriculture land use. Point source contributions to the total bioavailable P load (BAPL) are minor (5%), reflecting the benefit of reductions from recent treatment upgrades. The BAPL represented only about 26% of the total P load, because of the large contribution of the low bioavailable PP component. Most of BAPL (>70%) is received during high flow intervals. Large interannual variations in tributary flow and coupled BAPL will tend to mask future responses to changes in individual inputs. 相似文献
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Barry N. Haack 《Journal of the American Water Resources Association》1981,17(4):704-707
: A method is described for obtaining surface slope information for analysis with other land resource and water quality data in hydrologic models of nonpoint sources of water pollution. The method described requires a point sampling scheme, topographic maps, and a coordinate digitizer. Sample point elevation, slope direction, and slope magnitude are calculated from locations of the sample point and the nearest upper and lower contour lines. Details of the data collection methodology and associated problems are discussed. 相似文献
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Kent W. Thornton Robert H. Kennedy A. Dale Magoun Gary E. Saul 《Journal of the American Water Resources Association》1982,18(3):471-480
ABSTRACT: The design of monitoring programs often serves as one of the major sources of error or uncertainty in water quality data. Properly designed programs should minimize uncertainty or at least provide a means by which variability can be partitioned into recognizable components. While the design of sampling programs has received recent attention, commonly employed strategies for limnological sampling of lakes may not be completely appropriate for many reservoirs. Based on NES data, reservoirs are generally larger, deeper, and morphologically more complex than natural lakes. Reservoirs also receive a majority of their inflow from a single tributary located a considerable distance from the point of outflow. The result is the establishment of marked physical, biological, and chemical gradients from headwater to dam. The existence of horizontal as well as vertical gradients, and their importance in water quality sampling design were the subject of intensive transect sampling efforts at DeGray Lake, a U.S. Army Corps of Engineers reservoir in southern Arkansas. Data collected were used to partition Variance, identify areas of similarity, and demonstrate how an equitable sampling program might be designed. 相似文献
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Marc O. Ribaudo Jessica Gottlieb 《Journal of the American Water Resources Association》2011,47(1):5-14
Ribaudo, Marc O. and Jessica Gottlieb, 2011. Point‐Nonpoint Trading – Can It Work? Journal of the American Water Resources Association (JAWRA) 47(1):5‐14. DOI: 10.1111/j.1752‐1688.2010.00454.x Abstract: Water quality trading between point and nonpoint sources is of great interest as an alternative to strict command and control regulations on point sources for achieving water quality goals. The expectation is that trading will reduce the costs of water quality protection, and may speed compliance. The United States Environmental Protection Agency has issued guidance to the States on developing point‐nonpoint trading programs, and United States Department of Agriculture is encouraging farmer participation. However, existing point‐nonpoint trading programs have resulted in very few trades. Supply side and demand side impediments seem to be preventing trades from occurring in most trading programs. These include uncertainty over the number of discharge allowances different management practices can produce, high transactions costs of identifying trading partners, baseline requirements that eliminate low‐cost credits, the reluctance of point sources to trade with unfamiliar agents, and the perception of some farmers that entering contracts with regulated point sources leads to greater scrutiny and potential future regulation. Many of these problems can be addressed through research and program design. 相似文献