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761.
Formation and removal of PCDD/Fs in a municipal waste incinerator during different operating periods
The PCDD/F concentrations and removal efficiencies achieved with air pollution control devices (APCDs) during different operating periods (start-up, normal operation, and shut-down) at an existing municipal waste incinerator (MWI) in Taiwan are evaluated via stack sampling and analysis. The MWI investigated is equipped with electrostatic precipitators (EP), wet scrubbers (WS), and selective catalytic reduction system (SCR) as APCDs. The sampling results indicate that the PCDD/F concentrations at the EP inlet during start-up period were 15 times higher than that measured during normal operation period. The PCDD/F concentration observed at shut-down period was close to that measured at normal operation period. The CO concentration was between 400 and 1000 ppm during start-up period, which was about 50 times higher compared with the normal operation. Hence, combustion condition significantly affected the PCDD/F formation concentration during the waste incineration process. In addition, the distributions of the PCDD/F congeners were similar at different operating periods. During the normal operation and shut-down periods, the EP decreases the PCDD/F concentration (based on TEQ) by 18.4-48.6%, while the removal efficiency of PCDD/Fs achieved with SCR system reaches 99.3-99.6%. Nevertheless, the PCDD/F removal efficiency achieved with SCR was only 42% during the 19-h start-up period due to the low SCR operating temperature (195 degrees C). 相似文献
762.
763.
几种金属氧化物TPS性能比较 总被引:4,自引:2,他引:2
通过程度升温硫化研究了CuO,Fe2O3,SnO2,MnO2,CaO及ZnO等金属氧化物的脱硫性能,对各种金属氧化物的TPS曲线进行比较发现,其硫化温度及速度都不相同,氧化锰的硫化温度最低,从345K开始有较强的硫化氢吸收峰出现;氧化铜的硫化在373K左右进行;对氧化铁和氧化锌,硫化从473K开始,而氧化锡的硫化在650K左右发生;氧化钙的硫化发生在735K。粒度对TPS曲线有较明显的影响,粒度减 相似文献
764.
Yingying Zhang Juncheng Wang A. M. Vorontsov Guangli Hou M. N. Nikanorova Hongliang Wang 《Environmental monitoring and assessment》2014,186(1):515-524
The international marine ecological safety monitoring demonstration station in the Yellow Sea was developed as a collaborative project between China and Russia. It is a nonprofit technical workstation designed as a facility for marine scientific research for public welfare. By undertaking long-term monitoring of the marine environment and automatic data collection, this station will provide valuable information for marine ecological protection and disaster prevention and reduction. The results of some initial research by scientists at the research station into predictive modeling of marine ecological environments and early warning are described in this paper. Marine ecological processes are influenced by many factors including hydrological and meteorological conditions, biological factors, and human activities. Consequently, it is very difficult to incorporate all these influences and their interactions in a deterministic or analysis model. A prediction model integrating a time series prediction approach with neural network nonlinear modeling is proposed for marine ecological parameters. The model explores the natural fluctuations in marine ecological parameters by learning from the latest observed data automatically, and then predicting future values of the parameter. The model is updated in a “rolling” fashion with new observed data from the monitoring station. Prediction experiments results showed that the neural network prediction model based on time series data is effective for marine ecological prediction and can be used for the development of early warning systems. 相似文献
765.
In this semi-arid area, many studies focused on the two-phase vegetation pattern were carried out to explore a changing vegetation trajectory on degraded land. However, this study conducted an analysis of a two-phase vegetation pattern and explored the successional vegetation trajectories in a positive succession without disturbance. In this work, 60 randomly distributed plots (1?×?1 m) were invested on four abandoned land areas (4-, 12-, 22-, and 50-year abandoned land) to determine attributes of vegetation, and soil physical and nutritional properties. It was found that vegetation distribution development went from homogeneous on 4-year abandoned land to heterogeneous on 50-year abandoned land, with a positive succession. Meanwhile, there was a significant difference in soil physical and nutritional properties for the inside and outside of vegetation patches. Vegetation patches can supply better soil physical and nutritional properties for vegetation than bare patches along the abandoned time. Vegetation diversity changes without a regular trend which may be due to the effect of environment and interspecies competition. This work picked up the slack for vegetation patterns succession research and provided a quantitative analysis approach. 相似文献
766.
The temporal changes in road stormwater runoff quality and the implications to first flush control in Chongqing, China 总被引:1,自引:0,他引:1
Qianqian Zhang Xiaoke Wang Peiqiang Hou Wuxing Wan Yufen Ren Zhiyun Ouyang Le Yang 《Environmental monitoring and assessment》2013,185(12):9763-9775
This study investigates the quality of stormwater runoff from a driveway in the southwest mountainous urban area of Chongqing, China, from 2010 to 2011. The results showed that the mean concentrations of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) were 4.1, 2.4, and 2.2 times the grade V levels of the national surface water standard of China. The pollutant concentration peak preceded or synchronized with the rainfall intensity peak and occurred 10 min after the runoff started. The significant high pollutant concentration in the initial stage of the rainfall suggested that first flush control is necessary, especially for the most polluted constitutes, such as total suspended solids, COD, and TN. Three potential pollution sources were identified: the atmospheric dry and wet deposition (TN, NO3 ?-N, NH4 +-N, and DCu), the road sediment and materials (total suspended solids, COD, and TP), and the vehicle emissions (DPb and DZn). Therefore, this study indicates that reductions in road sediments and material pollution and dry and wet deposition should be the priority factors for pollution control of road stormwater runoff in mountainous urban areas. 相似文献
767.
采用膜分离—变压吸附耦合工艺处理DQ催化剂载体生产过程产生的高浓度挥发性有机物(VOCs)废气。实验结果表明:在进气正己烷和非甲烷总烃的质量浓度分别为95 000~212 000 mg/m3和100 000 ~220 000 mg/m3、渗余侧压力0.25 MPa、渗透侧真空度0.09 MPa、进气流量15 Nm³/h的条件下,膜分离单元对废气中正己烷及非甲烷总烃的平均去除率分别为97.88%和97.29%;变压吸附单元对正己烷及非甲烷总烃的平均去除率分别为99.35%和99.33%;整套装置对正己烷及非甲烷总烃的平均总去除率分别为99.99%和99.98%。平均正己烷回收率达95.56%。处理后废气中非甲烷总烃质量浓度小于70 mg/ m3,达到北京市DB 11/ 447—2007 《炼油与石油化学工业大气污染物排放标准》的一级指标。 相似文献
768.
M. T. Heitzmann M. Veidt C. T. Ng B. Lindenberger M. Hou R. Truss C. K. Liew 《Journal of Polymers and the Environment》2013,21(2):366-374
A single-plant biobased composite material was prepared from fibre and matrix constituents produced from the castor plant, ricinus communis. It is shown that the mechanical properties of the castor plant fibres are comparable to those of other bast fibres and that the stiffness and strength characteristics of the castor fibre/polyamide 11 biocomposite compare well with those of other natural fibre composites. By using a biobased thermoplastic matrix material the reliance on non-renewable feedstock sources is reduced and end-of-lifetime recyclability is improved. The analysis of the environmental performance of the new castor plant composite suggests that the biobased material has great potential as a sustainable alternative replacing glass fibre-reinforced plastics. 相似文献
769.
770.
Seasonal variations of CH(4) and N(2)O emissions in response to water management of paddy fields located in Southeast China 总被引:2,自引:0,他引:2
Water management is one of the most important practices that affect methane (CH4) and nitrous oxide (N2O) emissions from paddy fields. A field experiment was designed to study the effects of controlled irrigation (CI) on CH4 and N2O emissions from paddy fields, with traditional irrigation (TI) as the control. The effects of CI on CH4 and N2O emissions from paddy fields were very clear. The peaks of CH4 emissions from the CI paddies were observed 1-2 d after the water layer disappeared. Afterward, the emissions reduced rapidly and remained low until the soil was re-flooded. A slight increase of CH4 emission was observed in a short period after re-flooding. N2O emissions peaks from CI paddies were all observed 8-10 d after the fertilization at the WFPS ranging from 78.1% to 85.3%. Soil drying caused substantial N2O emissions, whereas no substantial N2O emissions were observed when the soil was re-wetted after the dry phase. Compared with TI, the cumulative CH4 emissions from the CI fields were reduced by 81.8% on the average, whereas the cumulative N2O emissions were increased by 135.4% on the average. The integrative global warming potential of CH4 and N2O on a 100-year horizon decreased by 27.3% in the CI paddy fields, whereas no significant difference in the rice yield was observed between the CI and TI fields. These results suggest that CI can effectively mitigate the integrative greenhouse effect caused by CH4 and N2O emissions from paddy fields while ensuring the rice yield. 相似文献