共查询到18条相似文献,搜索用时 78 毫秒
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大气汞污染问题已引起各国的重视,其中汞污染物主要来源于燃煤电厂,防治燃煤电厂汞污染是21世纪电力工业急待解决的问题。针对该问题,笔者对燃煤电厂汞排放控制途径进行了分析,并对燃煤电厂采用的除尘脱硫系统的附带脱汞效果进行了比较和分析,探讨了燃煤电厂控制汞排放的控制途径。 相似文献
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燃煤锅炉排放的汞已成为我国最大的人为汞排放污染源。汞具有神经剧毒性、大气迁移性和生物累积性等特征,对自然环境和人类健康构成严重危害,已在全球范围内引起广泛关注。目前我国燃煤电厂汞排放控制主要采用现有污染物控制装置(APCDs)的协同脱汞技术。随着我国燃煤电厂"近零排放"目标的实施,烟气汞排放浓度、灰渣和废水汞含量的排放限值将日趋严格。笔者首先概述了当前我国燃煤电厂汞污染物大气排放标准快速更新的现状,指出应对日趋严格的汞排放限值需要对燃煤锅炉系统进行深度脱汞。然后介绍了烟气汞浓度检测技术的发展,以应对大气汞排放浓度的监测和监管。第三,综述了燃煤脱汞技术,详述了APCDs协同脱汞、烟气喷射吸附剂脱汞技术的研究进展,指出了新型脱汞吸附剂的研发趋势。第四,论述了我国燃煤电厂正在实施的超低排放改造对汞减排的效果。最后,针对目前燃煤电厂脱汞技术存在的问题,提出前瞻性的脱汞研究课题,以期对燃煤电厂实现"汞零排放"和副产物中汞的稳定化提供科学参考。 相似文献
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燃煤电厂在日常经营管理过程中,主要是通过燃煤的方式实现对电力的供应。但是这种方式,很有可能会对大气造成严重的污染,因此对燃煤电厂超低排放改造前后的汞污染情况进行分析,为大气环境提供良好的保护措施。 相似文献
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《洁净煤技术》2021,27(5)
目前燃煤电厂烟气汞的治理主要依靠常规污染物净化装置协同脱除。为了解我国超低排放电厂污染物净化设施的协同脱汞能力,对电厂汞排放现场测试数据进行统计分析。研究发现相同类型的污染物净化设施对汞的脱除能力有很大差别,选择性催化还原法(SCR)的汞氧化效率在13.2%~91.1%,平均氧化效率为52.7%;不同类型除尘器对汞的去除效果差异很大,其中低低温电除尘器(LLT-ESP)电袋除尘器(ESP+FF)普通电除尘器(ESP)。湿式石灰石-石膏法(WFGD)脱硫系统脱汞平均脱汞效率为54.3%,大部分WFGD的脱汞效率主要由Hg~(2+)的去除贡献得到。不同超低排放改造技术路线中以低低温电除尘器为核心的技术路线的平均脱汞效率最高,为91.3%。超低排放改造后机组的平均脱汞效率为80.1%,相比改造前提高约10%。 相似文献
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燃煤电厂汞污染已经成为继SO2污染之后的又一重大污染问题。燃煤烟气中汞污染的控制研究是目前重要的环保课题之一,开发高效、低成本、无二次污染的烟气脱汞技术已成为研究重点。本文综述了国内外在汞的监测方法、汞在燃煤电厂中的迁移规律以及汞污染物控制措施等方面的研究进展,并做了简要的分析与总结,对未来燃煤烟气汞污染控制技术的发展进行了展望。 相似文献
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总结了排污权交易制度的主要作用,在此基础上分析了这一制度在我国实施中可能存在的问题,最后讨论了该制度对我国燃煤电厂污染排放的影响。 相似文献
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电厂煤燃烧过程中汞的形态分布及迁移转化行为分析 总被引:3,自引:0,他引:3
阐述了煤炭燃烧过程中汞的形态分布和迁移转化行为。说明煤炭燃烧过程,汞主要以Hg^0形态存在。用化学热力学的理论对不同的煤样中汞的燃烧形态变化进行了计算分析,并描述了温度对其迁移转化的影响和作用。 相似文献
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《Journal of Sulfur Chemistry》2013,34(5):457-475
Coal combustion continues to be a major source of energy throughout the world and is the leading contributor to anthropogenic mercury emissions. Effective control of these emissions requires a good understanding of how other flue gas constituents such as sulfur dioxide (SO2) and sulfur trioxide (SO3) may interfere in the removal process. Most of the current literature suggests that SO2 hinders elemental mercury (Hg0) oxidation by scavenging oxidizing species such as chlorine (Cl2) and reduces the overall efficiency of mercury capture, while there is evidence to suggest that SO2 with oxygen (O2) enhances Hg0 oxidation by promoting Cl2 formation below 100 °C. However, studies in which SO2 was shown to have a positive correlation with Hg0 oxidation in full-scale utilities indicate that these interactions may be heavily dependent on operating conditions, particularly chlorine content of the coal and temperature. While bench-scale studies explicitly targeting SO3 are scarce, the general consensus among full-scale coal-fired utilities is that its presence in flue gas has a strong negative correlation with mercury capture efficiency. The exact reason behind this observed correlation is not completely clear, however. While SO3 is an inevitable product of SO2 oxidation by O2, a reaction that hinders Hg0 oxidation, it readily reacts with water vapor, forms sulfuric acid (H2SO4) at the surface of carbon, and physically blocks active sites of carbon. On the other hand, H2SO4 on carbon surfaces may increase mercury capacity either through the creation of oxidation sites on the carbon surface or through a direct reaction of mercury with the acid. However, neither of these beneficial impacts is expected to be of practical significance for an activated carbon injection system in a real coal-fired utility flue gas. 相似文献
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燃煤烟气中的SO3会对机组运行及大气环境造成不利影响。为研究燃煤电厂SO3排放特征,本文采取异丙醇吸收法对某300MW超低排放机组污染物控制装置进出口SO3采样,以分析SO3在燃煤机组中的迁移及脱除特性。结果表明:炉膛燃烧过程以及选择性催化还原装置(selective catalytic reduction,SCR)均将部分SO2转化为SO3,炉膛燃烧生成SO3的质量浓度为SO2的0.86%,SCR内SO2/SO3转化率为0.45%。烟气经过空气预热器,SO3浓度降低了5.7%;静电除尘器(electrostatic precipitator,ESP)脱除SO3效果较差,主要由于ESP内烟温在110℃以上,H2SO4酸雾凝结量较少;双级湿法脱硫装置(wet flue gas desulfurization,WFGD)对SO3脱除效率达到81.3%,比国内单级脱硫装置SO3脱除效果高30%~50%;湿式静电除尘器(wet electrostatic precipitator,WESP)脱除SO3效率为23.0%。机组烟囱排放SO3质量浓度为2.025mg/m3(标准),SO3排放因子EF为0.034kg/t。 相似文献
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On-site measurements of volatile organic compounds (VOCs) in different streams of flue gas were carried out on a real coal-fired power plant using sampling bags and SUMMA canisters to collect gas samples,filters to collect particle samples,Gas chromatography-flame ionization detector/mass spectrometry and gas chromatography-mass spectrometry was the offline analysis method.We found that the total mass concentration of the tested 102 VOC species at the outlet of wet flue gas desulfuration device was (13456 ± 47) μg·m-3,which contained aliphatic hydrocarbons (57.9%),aromatic hydrocarbons(26.8%),halogen-containing species (14.5%),and a small amount of oxygen-containing and nitrogen-containing species.The most abundant species were 1-hexene,n-hexane and 2-methylpentane.The top ten species in terms of mass fraction (with a total mass fraction of 75.3%) were mainly hydrocarbons with a carbon number of 6 or higher and halogenated hydrocarbons with a lower carbon number.The mass concentration of VOC species in the particle phase was significantly lower than that in the gas phase.The change of VOC mass concentrations along the air pollution control devices indicates that con-ventional pollutant control equipment had a limited effect on VOC reduction.Ozone formation potential calculations showed that aromatic hydrocarbons contributed the highest ozone formation (46.4%) due to their relatively high mass concentrations and MIR (maximum increment reactivity) values. 相似文献
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制备了具有工业应用价值的V2O5/TiO2负载WO3与MoO3的蜂窝状SCR催化剂,并在某燃煤电厂烟气环境下,对其催化性能进行了测试,结果表明:增大催化剂体积能够提高脱硝效率,但活性增量逐步下降,当脱硝效率达到80%以上时,继续增大催化剂体积其活性提高不显著。催化剂的脱硝活性随着积灰时间的延长而降低,脱硝系统运行4 h后,催化剂脱硝活性减少9.4%。在燃煤电厂尾气飞灰浓度约为0.031 kg·m-3环境下,为满足尾气中NOx浓度排放要求(<200 mg·m-3),每连续运行6 h需进行一次吹灰。催化剂的脱硝性能随着运行时间的延长,先急剧下降,后缓慢降低。在连续运行48~168 h范围内,脱硝活性下降值小于1%,SO2氧化率下降值小于0.1%。在12个月内,平均每连续运行700 h,脱硝活性降低1%。 相似文献
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对目前国内外各种脱碳技术进行了介绍和分析,并根据烟气特点提出了燃煤电厂烟气脱碳技术的选择条件,推荐了目前适合于燃煤电厂烟气脱碳的醇胺法脱碳技术。在此基础上,对醇胺法吸收剂的选择及工艺配置给出了具体的建议。 相似文献