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791.
792.
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
793.
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
794.
Liyuan Chai Xu Yan Qingzhu Li Bentao Yang Qingwei Wang 《Environmental science and pollution research international》2014,21(21):12436-12444
Abiological granular sludge (ABGS) formation is a potential and facile strategy for improving sludge settling performance during zinc removal from wastewater using chemical precipitation. In this study, the effect of pH, seed dosage, and flocculant dosage on ABGS formation and treated water quality was investigated. Results show that settling velocity of ABGS can reach up to 4.00 cm/s under optimal conditions, e.g., pH of 9.0, zinc oxide (ZnO) seeds dosage of 1.5 g/l, and polyacrylamide (PAM) dosage of 10 mg/l. More importantly, ABGS formation mechanism was investigated in NaOH precipitation process and compared with that in bio-polymer ferric sulfate (BPFS)–NaOH precipitation process regarding their sludge structure and composition. In the NaOH precipitation process, ABGS formation depends on some attractions between particles, such as van der Waals attraction and bridging attraction. However, during the BPFS–NaOH sludge formation process, steric repulsion becomes dominant due to the adsorption of BPFS on ZnO seeds. This repulsion further causes extremely loose structure and poor settling performance of BPFS–NaOH sludge. 相似文献
795.
796.
Studies of the history and current status of forest resources in Northeast China have become important in discussions of sustainable
forest management in the region. Prior to 1998, excessive logging and neglected cultivation led to a series of problems that
left exploitable forest reserves in the region almost exhausted. A substantial decrease in the area of natural forests was
accompanied by severe disruption of stand structure and serious degradation of overall forest quality and function. In 1998,
China shifted the primary focus of forest management in the country from wood production to ecological sustainability, adopting
ecological restoration and protection as key foci of management. In the process, China launched the Natural Forest Conversion
Program and implemented a new system of Classification-based Forest Management. Since then, timber harvesting levels in Northeast
China have decreased, and forest area and stocking levels have slowly increased. At present, the large area of low quality
secondary forest lands, along with high levels of timber production, present researchers and government agencies in China
with major challenges in deciding on management models and strategies that will best protect, restore and manage so large
an area of secondary forest lands. This paper synthesizes information from a number of sources on forest area, stand characteristics
and stocking levels, and forest policy changes in Northeastern China. Following a brief historical overview of forest harvesting
and ecological research in Northeast China, the paper discusses the current state of forest resources and related problems
in forest management in the region, concluding with key challenges in need of attention in order to meet the demands for multi-purpose
forest sustainability and management in the future. 相似文献
797.
主要分析了河北省发展低碳经济优化升级产业结构的驱动力,借鉴发达国家低碳经济与产业结构调整运行机制的实践经验,提出了发展河北省低碳经济与产业结构调整运行机制的策略。 相似文献
798.
以乳化炸药螺杆泵为研究对象,画出系统功能方框图和可靠性方框图,应用故障模式及影响分析方法(FMEA),确定螺杆泵的各种可能故障模式、故障原因和故障影响。同时计算出各故障的风险度,并依次对故障进行分级,找出对螺杆泵危害严重的故障。最后建立FMEA表格,并根据分析结果提出提高其可靠性的建议措施。 相似文献
799.
Khan Irfan Hou Fujun 《Environmental science and pollution research international》2021,28(5):5049-5062
Environmental Science and Pollution Research - We examine the impact of energy consumption and tourism growth on the ecological footprints and economic growth of 38 International Energy Agency... 相似文献
800.
五氟磺草胺的光解特性研究 总被引:1,自引:0,他引:1
通过室内模拟的试验方法研究了五氟磺草胺在高压汞灯下的光解特性。五氟磺草胺在pH5、7、9的缓冲溶液中光解半衰期分别为23 min、20.6 min、18.7 min,随着pH的升高光解速率加快。在五氟磺草胺浓度为1 mg/kg、2 mg/kg、5 mg/kg的水溶液中半衰期分别为14.2 min、17.5 min、22.1 min,光解速率随着浓度的升高而减慢。在1 g/L、2 g/L的腐殖酸溶液中五氟磺草胺的半衰期分别为6.6 min、4.6 min,其光解速度是水中的4~5倍。五氟磺草胺在0.1 g/L的UV531溶液中半衰期为27.8 min,在0.2 g/L的溶液中半衰期为35.8 min,半衰期比在水溶液中延长60%。 相似文献