国内外水泥工业汞排放现状及汞减排的思考

通过分析UNEP发布的《全球汞评估报告》,总结了国内外水泥工业汞排放现状,对比了全球主要水泥生产国的汞排放系数,研究了燃煤对水泥工业汞排放的重要影响.2015年全球水泥工业汞排放总量为277t,我国水泥工业汞排放总量为134.05t.结合水泥工业特点,分析了汞减排技术及效率,提出了我国水泥工业汞减排的最佳途径.     

石油中汞的分析方法进展

综述了石油中汞的来源、汞含量及汞形态的分析方法以及石油中汞的危害。     

燃煤电厂汞排放与控制技术研究进展

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。     

新型高效除汞器在氯乙烯合成气除汞中的应用

针对传统除汞器存在的除汞效果差、系统阻力大、劳动强度高等弊端,研发设计出了气相汞回收高效除汞器,满足了生产装置的使用要求。     

气田水中汞的形态分析

汞具有高挥发性、高毒性及腐蚀性,对人身、设备及环境具有重大危害,严重影响了气田开发和利用的安全性,目前已引起了涉汞油气田的高度关注。气田水中不同汞形态主要由难溶性汞(悬浮汞),可溶态汞(单质汞、无机汞、有机汞)组成。气田水中汞形态分析的前处理方法主要有金管富集法、液液萃取法、蒸馏法和膜分离法等。汞形态分析方法主要有气相色谱法、高效液相色谱法、质谱法、原子吸收光谱法及各分析方法之间的联用技术。研究分析气田水中汞的形态,可为气田水选择适当的净化处理技术。同时为气田作业区汞防护措施研究提供依据,做好汞污染的防控。     

天然气中汞的脱除技术

鉴于环保、设备安全以及人身健康的要求,有效脱除天然气中汞的应用技术日渐受到重视。简述了物理吸附、化学吸附、溶液吸收和低温分离等具有代表性的天然气脱汞的工艺进展。对活性炭汞吸附剂、负载金属吸附剂、卤化或载硫活性炭和其他类型汞吸附剂在天然气中汞脱除的应用进展进行了阐述。研究了入口天然气的温度和湿度对脱汞效果的影响,较低的温度和湿度有利于汞的脱除。     

电石法聚氯乙烯生产中汞消耗与汞污染的降低

分析了影响汞消耗和汞污染的相关因素,并针对性地提出了降低汞消耗与汞污染的方法,指出开发应用低汞触媒具有现实意义。     

低固汞触媒工业化应用

介绍了新疆天业(集团)有限公司自主研发和生产的低固汞触媒的工业化应用效果和优点,提出确保和延长低固汞触媒使用寿命的措施,以及低固汞触媒工业化应用在汞减排方面取得的显著成绩。     

硫化铜脱汞剂的制备及脱汞性能研究

以氧化铝分子球为载体、硫化铜为活性物质,采用浸渍工艺制备了硫化铜脱汞剂。利用固定床汞吸附装置研究了铜盐浓度、浸渍比、焙烧温度及烘干温度等工艺参数对硫化铜脱汞剂脱汞性能的影响,结合XPS对制备的各个步骤中前驱体有效成分进行了表征。实验结果表明,铜盐质量分数为15%、浸渍比为60 m L铜盐溶液:20 g氧化铝、焙烧温度为150℃及烘干温度为30℃时,实验制备得到的硫化铜脱汞剂脱汞性能最佳,汞容达到8. 925×10^-4g/g。其脱汞性能随焙烧温度、铜盐质量分数和浸渍比的增大先升后降,随烘干温度升高持续降低。     

铜仁市汞矿区内土壤汞污染的调查分析

为深入了解铜仁汞矿区内土壤总汞和气态汞的污染特性,应用原子荧光吸收光谱法,分别对铜仁万山、云场萍和路腊村汞矿区不同位置土壤中的总汞和气态汞进行了测定。结果表明铜仁市汞矿区土壤中总汞和气态汞的均值为162.75 mg/kg和86.26 mg/kg,明显高于其他城市,这可能与铜仁的工业历史有关。研究表明,炼汞废渣可能是农田土壤中汞污染的主要来源和大气的沉降作用是农田土壤中汞污染的主要途径。     

Radiometric studies of mercury loss from fungicidal paints III. Loss from three paints with various mercury contents

Losses of mercury have been measured over a period of 220 days from paint films prepared from polyvinyl acetate emulsion (PVA), styrene/acrylic emulsion or alkyd gloss paints containing concentrations of mercury as phenyl mercuric acetate (PMA) from 0.005 to 0.16%. At all concentrations, simple PVA films lose mercury at lower rates than do comparable films prepared from PVA containing coalescing agent, or from styrene/acrylic emulsion. Mercury losses from alkyd gloss films are lower than those from other films at the lower mercury concentrations studied, but percentage loss rates for alkyd films increase somewhat with increasing mercury concentration. A simple explanation for this difference is offered in terms of physical structures of the paint films.     

加强汞污染防治 实现聚氯乙烯清洁生产

介绍了电石乙炔法生产氯乙烯工艺中氯化汞催化剂汞的流向、汞的流失查定及汞的削减措施等。     

Radiometric studies of mercury loss from fungicidal paints. 1. Loss of phenyl mercuric acetate

Exposure tests have been made on paint films prepared from an emulsion paint containing phenyl mercuric acetate (PMA) labelled with ²⁰³Hg. Loss of mercury from the films has been followed radiometrically. Films exposed indoors in a confined space (no air circulation) showed little, if any, mercury loss for up to 8 months. Films exposed in the open laboratory lost from 20 to more than 60% of mercury after 250 days. This agrees qualitatively with the results of other workers on similar paints. At 50°, films lost mercury at rates about 10 times greater than those at ambient temperature. Films exposed out-of-doors lost the majority of their mercury after a few days of rain. Pre-treatment of films, e.g. by u.v. radiation, had no effect on their subsequent outdoor behaviour. Even well-dried films lost mercury at the same rate as newly applied films. Films with a low PMA content (0·02% Hg) lost mercury at a higher percentage rate than films with a high one (0·2% Hg). Thick films (0·002 in.) lost mercury at a lower rate than thin ones (0·001 in.). A mercury-free top coat also reduced loss rate. All loss rates decreased with increasing time. These trends applied to all the exposure conditions studied. Mercury loss appears to be due to both volatilisation and dissolution of PMA and not to decomposition. The results indicate a non-homogeneous distribution of PMA throughout the paint film, and a diffusion-controlled process.     

Surface chemical characterization of deactivated low-level mercury catalysts for acetylene hydrochlorination

Mercury-containing catalysts are widely used for acetylene hydrochlorination in China. Surface chemical characteristics of the fresh low-level mercury catalysts and spent low-level mercury catalysts were compared using multiple characterization methods. Pore blockage and active site coverage caused by chlorine-containing organics are responsible for catalyst deactivation. The reactions of chloroethylene and acetylene with chlorine free radical can generate chlorine-containing organic species. SiO₂ and functional groups on activated carbon contribute to the generation of carbon deposition. No significant reduction in the total content of mercury was observed after catalyst deactivation, while there was mercury loss locally. The irreversible loss of HgCl₂ caused by volatilization, reduction and poisoning of elements S and P also can lead to catalyst deactivation. Si, Al, Ca and Fe oxides are scattered on the activated carbon. Active components are still uniformly absorbed on activated carbon after catalyst deactivation.     

新型高效脱汞器在氯乙烯气相脱汞中的应用

介绍了一种新型高效的脱汞设备及脱汞工艺。该脱汞器用于电石法氯乙烯生产过程中气体汞的脱出,汞脱出率平均达到80％,脱汞器的压降比传统脱汞器下降50％。     

DMA-80汞分析仪测定粗制氧化锌中的汞

建立了DMA-80型汞分析仪直接固体进样测定粗制氧化锌中汞的方法。试样经干燥和高温分解处理,采用催化分解和吸附净化使分解产物转变为氧化汞蒸气,通过金质汞齐化器还原并以金汞齐形式被捕集,最后在波长253.65 nm处进行原子吸收测量,依据朗伯-比尔定律定量。优化了干燥时间和温度、分解时间和温度等实验条件,同时做了方法检出限、精密度、回收率等实验。结果表明：方法检出限为0.015 ng,线性范围为0.02~100 ng,相关性系数≥0.999,回收率为93.2%~102.7%,精密度（RSD,n=7）≤5.0%,可用于进口粗制氧化锌的快速检验。     

电石法聚氯乙烯汞减排路线的探讨与实践

介绍了电石法聚氯乙烯生产过程中汞的流向及聚氯乙烯发展面临的巨大挑战。探讨和分析了汞减排路线：①使用高品质低汞催化剂;②发挥除汞器的作用,力争将汞污染控制在最短流程;③应用组合吸收一常规解吸一深度解吸工艺,杜绝含汞废酸污染;④采用硫化钠类沉降剂处理含汞废水。阐述了无汞催化剂的研发现状。     

Atomic fluorescence determination of mercury in fresh water ecosystems

This paper reports on an investigation into determining nanogram/l quantities of mercury in marine and fresh water matrices using a cold vapour generation of mercury, followed by fluorescence detection. Samples were prepared for analysis using a free bromine oxidation technique. A high efficiency gas-liquid separator was used to enhance the detection of mercury. For fresh water, typical method detection limits (MDL) were determined at less than 1 nanogram/l (ng/l). For near shore seawater, the MDL was 1.2 ng/l. Method spikes, which were performed at 20 ng/l, showed mean recoveries within US EPA Contract Laboratory Protocol (CLP) acceptance criteria. System blanks averaged 0.12 ng/l, and recoveries of NIST 1641c diluted to 29.4 ng/l averaged 93.4%. A number of local rivers and streams were sampled, and mercury was determined. All results to date indicate mercury levels below the US EPA chronic water quality criteria for mercury.     

可循环再生吸附剂脱汞技术现状及发展趋势

总结了当前燃煤烟气脱汞常用的协同脱汞技术和贵金属、金属氧化物基可再生吸附剂技术发展现状,分析了各方法的优势与存在的问题,对未来磁性可回收吸附剂的发展方向和趋势进行了展望。针对现有脱汞技术效率低、易造成二次污染等缺陷,提出了使用飞灰磁珠制备廉价可回收脱汞吸附剂的新思路。通过大量试验开发了负载Co_3O_4或CuCl_2的磁珠改性方法以增强脱汞能力和抗烟气组分干扰能力,从而能够适用于低氯复杂烟气气氛。设计了改性磁珠吸附剂喷射脱汞工艺流程,可兼顾高效脱汞与低廉的运行成本,并通过磁珠回收再利用彻底避免汞进入环境造成污染。     

Capillary electrophoretic separation and post-column electrochemical detection of mercury and methyl mercury and applications to coal samples

A study of the electrochemistry of mercury and organo mercury complexes with cysteine indicated the formation of stable complexes which can be utilized for the determination of the species in environmental matrices. A technique based on capillary electrophoresis and amperometric detection (CE-AD) has been developed for the speciation of mercury with a newly developed cross hair design electrochemical detector. This technique has the capability to detect mercury species that are electrochemically active. For CE-AD the detection limits were 0.005 ± 0.002 μg L⁻¹ for Hg²⁺ and 0.4 ± 0.05 μg L⁻¹ for MeHg⁺. These detection sensitivities are very attractive for environmental monitoring and the method was utilized for the determination of mercury in coal.