探讨高炉出铁场颗粒物无组织排放治理——以天津市某钢铁企业为例

铜铁企业在污染物有组织排放控制技术上比较成熟面对日益严峻的环保形势和要求,企业必须加强无组织排放控制,对高炉出铁场无组织控制技术进行改造创新,以提升其除尘效果、减少污染物排放,改善现场环境本文以天津市某铜铁企业为例,介绍其高炉出铁场颗粒物无组织排放治理改造方案的具体情况及污染物减排量,以期为其他企业的环保治理作为借鉴。     

布袋除尘+湿式电除尘器改造应用

本文是针对350MW燃煤机组烟尘超净排放改造应用实践进行的论述,介绍了原有布袋除尘器的情况以及存在的问题,并围绕布袋除尘器开展改造方案的论证,提出了布袋除尘器加设湿式电除尘器与脱硫系统协同除尘的方案,介绍了湿式静电除尘器原理以及应用于本工程的技术优势。工程改造后通过性能测试满足性能保证值出口粉尘不大于5mg/m~3,同时SO_3的脱除效率为70.5%,满足不小于70%性能要求。布袋除尘器加设湿式电除尘器与脱硫系统协同除尘实现超净排放,取得了显著的环保效益,也为其他机组的改造提供了应用经验。     

3×300t转炉二次除尘系统改造工程

宝钢股份公司第一炼钢厂除尘系统扩容改造项目中,风量为300万m3/h的转炉二次脉冲布袋除尘器是目前国内冶金行业最大的布袋除尘器改造工程。针对除尘工艺流程、主要设备参数、系统技术优势以及实际运行效果进行了叙述,项目投产后运行良好,车间环境得到有效的改善,烟气排放达标。     

高炉炼铁工艺细颗粒物PM2.5排放特性分析

采用静电低压撞击器(electrical low pressure impactor,ELPI)对高炉出铁场、矿槽除尘后细微颗粒物(PM2.5)的粒径及质量浓度分布进行在线分析.结果表明,出铁场除尘后PM2.5粒数浓度在105~106cm-3数量级范围内,主要为粒径小于0.1μm的颗粒物,而矿槽除尘后PM2.5粒数浓度在104~105cm-3数量级范围内,主要为粒径1.0μm以下的颗粒物,质量浓度呈单峰分布;PM2.5化学组成分析表明水溶性离子SO2-4、K+、Ca2+含量较高,分别为10.32%~28.55%、10.36%~12.15%、3.97%~15.4%;主量元素主要为Fe、Si、Al,含量分别为16.8%~31.62%、2.24%~8.76%、1.24%~5.89%;含碳组分OC和EC在PM2.5中的含量也较为丰富,分别为2.7%~4.6%和0.8%~1.3%.PM2.5单体颗粒形态主要为球状颗粒和不规则颗粒.高炉出铁场、矿槽除尘后PM2.5的排放因子分别为0.045~0.085 kg·t-1、0.042~0.071 kg·t-1.     

首钢2#高炉出铁场除尘技术历次改造的剖析

通过对首钢 2 #高炉三次改造的剖析 ,陈述了高炉出铁场除尘系统从无到有 ,不断改进和完善 ,直至实现清洁化生产的典型发展历程。文中从技术角度分析了出铁场除尘的难点 ,特别指出结合出铁工艺 ,设计合理的捕集罩是解决问题的关键     

宝钢中厚板分公司煤干燥机除尘系统风量调整技术探究

文章针对宝钢股份中厚板分公司炼铁厂煤干燥机除尘系统吸尘点冒灰,粉尘无组织排放超标的现象进行了测试分析,数据表明主要由除尘系统风量匹配不佳、吸尘点风量不合理造成。笔者通过不断调整阀门及风机档板开摩,测试调整后的风量、除尘性能、岗位粉尘浓度等参数,确定了一个合理的系统风量,不仅可以达到环境排放及职业卫生的要求,而且充分挖掘了除尘系统潜力,达到了节能降耗、经济运行的目的,同时对类似除尘系统风量匹配不佳、扬尘等问题也形成了有效的解决方案。     

大型高炉除尘工程设计

目前国家钢铁行业政策明确要求:炼铁高炉应大型化以更好满足环保和节能减排的要求。新建大型高炉有效容积一般在3 200～5 500 m3之间,其除尘系统一般划分为供料、出铁场、炉顶等三个除尘系统,采用高效捕集罩、高效布袋除尘器、高效电机变频调速节能等技术。国内大型高炉的设计、建设、生产水平,已经达到国际先进水平。     

运煤系统粉尘综合治理方案评估

通过对运煤系统的除尘系统的设计及评估,将3种除尘过程进行详细的比较分析,得出,布袋除尘器方案技术合理,初投资最低,运行费用适中。因此推荐布袋除尘器作为本工程输煤系统除尘方案。     

一种高效超低排放组合式除尘净化装置

依据现行的技术规范、以往工程项目的设计经验,介绍了一种高效超低排放组合式烟气除尘净化装置降阻提效技术,组合式烟气除尘净化装置是由进气烟箱机械振打预除尘部分、一个电场电除尘器部分、布袋除尘器部分组成,组合式烟气除尘净化装置阻力的优化设计降低了总体阻力,延长布袋除尘器滤袋、脉冲阀的使用寿命,同时可以降低布袋除尘器总体阻力,节省电耗,降低除尘器的运行、维护费用,保证了除尘净化装置出口排放浓度长期在15 mg/m3以下高效运行,同时延长了系统的使用寿命,节省能耗,具有一定的经济意义。     

炼铁厂的烟尘控制

炼铁厂是钢铁企业中散发污染物的主要车间之一,国内现有高炉烟尘控制尚不够完善,至今还是钢铁厂的一个薄弱环节。炼铁厂的烟尘控制必须妥善解决高炉矿槽、出铁场及铸铁机室的除尘,特别是矿槽卸料小车、料坑、出铁场、以及铸铁机等处的除尘。从目前国内的实际情况出发,只要提高认识,认真总结经验,加强综合防治,炼铁厂的烟尘是有办法治理的,也是可以治理好的。     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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