低成本去除电弧炉废气中二恶英的方案

钢铁工业承受着不断降低工艺废气中所含二恶英和其他有害排放物的巨大压力。在20世纪90年代初,奥钢联开始研究用于烧结厂和电弧炉的新型废气净化系统并显著提高了净化效率。对新方案及其实际应用效果进行介绍。     

干法净化氟化盐富集氧化铝中除去杂质

采用新鲜氧化铝作为净化剂并采用干法净化工艺清理铝电解槽废气。新鲜氧化铝在电解槽回路系统中通过氟化盐和痕量杂质富集。杂质主要是在出铝时除去。开发出了一种比早期的脱模系统更有效的先进技术。在富集氧化铝中含杂质较多的细颗粒（〈１０μｍ）地附着于粗颗粒氧化铝上，这种结合必须要打破。在特殊的和适当的条件下采用选择性冲击磨和气流分级已证明是一种经济有效的除杂质的方法。通过分离０．５－１％的氧化铝可除去约３０－     

燃气轮机废气再燃烧烧嘴的开发

最近，燃气轮机废气再燃烧的合成循环系统作为增强现有火力发电输出功率和提高火力发电效率的有效手段特别引人注目．在本系统中，由于锅炉采用燃气轮机的废气进行燃烧，因此，如果废气中的氧浓度过低，燃烧火焰会变得不稳定．为解决这个问题，三菱重工公司成功地开发出了燃烧火焰稳定性好的新型废气再燃烧烧嘴，即使废气的浓度为１２％（湿体积）时这种烧嘴也能进行稳定的着火燃烧。本文介绍其试验结果。     

MEROS——烧结废气净化新工艺

为达到更多的环保及生态要求,解决钢铁厂烧结机废气净化问题,西门子下属VAI工程技术有限公司开发一项名为MEROS的钢厂废气净化新技术。MEROS是英文该词中每个字头一个字母的拼合,含义是:最大限度地减少烧结排放。经过数阶段净化废气中存在的粉尘,有害元素及有机物质能以采用传统净化方法无法达到的效果被清除。世界首套MEROS高效净化装置目前正在奥地利的林茨奥钢联公司一家大型钢铁厂现场施工及安装,不久即将投产运行。根据MEROS工艺流程,在对废气进行净化处理当中采用这样一些污染物吸附材料,例如经专门处理的木质褐煤焦炭,或活性炭,以及脱硫反应剂,例如熟石灰或碳酸氢纳等。使用这些材料时,以均匀的料流及与废气流方向相反,用极快的流速将这些吸附材料投入烧结废气流中。在调节反应器的特殊装置里上述各种吸附材料与重金属类,含硫化合川的及有机化合物(二恶英、呋喃)等化合。接着用此反应装置中下部所装双作用(水———压缩空气)高效率喷嘴湿润废气及降低废气温度,借此加速二氧化硫及其它含硫成分的化学化合反应。数量很少的零星颗粒物(碎烧结矿及烧结混合料残粒),从反应装置底部卸出用皮带运输机系统收集,待运。从反应装置出来的烧结废气充满灰尘(内...     

硫金精矿火法熔炼二氧化硫废气治理的研究

本文对低浓度SO_2(1～0.7％)废气净化治理工艺进行了论述。其一,采用石灰乳和含碱选矿尾水交替使用,有效控制硫酸盐结垢,实现了废气、废水综合治理,SO_2净化效率91.58％。其二,采用碳酸钠法吸收工艺,SO_2净化效率97.2％,硫资源得到回收利用,产出无水亚硫酸钠产品。     

从含金钯废气敏元件中回收金钯工艺的研究

研究了一种从含金钯废气敏元件中优先分离金,然后回收钯的工艺。废料经溶解－两次还原可获得９９．９９％的高纯金,总效率为９９．５％,获得的钯纯度为９９．９９％,直收率为９８．５％。     

从润滑油源中将钼输送到燃料燃烧系统

本发明涉及一种将钼从润滑油源中输送到燃烧系统或其废气中的设备和方法。通过本发明，润滑油或燃料中的钼与来自燃烧产物中磷、硫、和／或铅进行反应。照这样，钼对聚集于燃料或燃烧产物中的有害物质进行净化或使其失活，这些有害物质否则会毒害催化转化器、传感器和／或汽车携带的诊断设备。本发明也可使排气后处理系统耐用性提高。     

相关行业

净化汽车尾气的三元催化剂日本马自达汽车公司日前开发出比原产品更能有效降低汽车尾气中所含有害物质的汽油发动机三元催化剂。通常安装在汽车排气管中的催化剂达到250℃—300℃的活性温度后,可净化汽车尾气中所含的有害物质碳化氢、一氧化碳和氮氧化物。为进一步净化汽车尾气,在     

锻造用高强度低合金钢的发展

杂质成分和热处理工艺对高强度合金钢结构和性能的影响已经进行试验，在此基础上，对0．2％的这些钢通过增加（0．17％－0．23％）的铌，同时增加0．2％的镍，0．4％-0．6％的铬和1．5％－1．8％的锰，开发出具有贝氏体或自动回火马氏体的基体的高强度锻造用的钢是可能的，这些钢的微观结构和力学性能对冷却速度和热处理工艺是灵敏的。     

汽车尾气净化用金属载体

汽车尾气净化用的载体中,陶瓷载体的市场覆盖率达９０％,但为了缩短开始净化的时间和提高产品性能,新日本制铁公司开发出废气净化用不锈钢载体,即用耐热性能良好的不锈钢（２０Ｃｒ５Ａｌ）生产不锈钢箔,再将这种不锈钢箔加工成蜂窝状,在其内侧附着催化剂便形成了金属载体。为了提高产品性能和降低生产成本,该公司于１９９７年开发出３０μｍ厚的不锈钢箔。目前丰田汽车公司已有７个车种采用了这种新产品,主要是用于高级轿车。预计使用３０μｍ不锈钢箔的汽车尾气净化用金属载体将占主导地位。汽车尾气净化用金属载体@凤林     

Research and industrial testing of dioxin emission reduction technology in the sintering process

Based on an analysis of the chlorine elements in each component of the sintering mixture,industrial tests of the use of dioxin reduction techniques in the sintering process were found to reduce the chlorine sources and inhibit the formation of dioxins.The dioxin reduction effect obtained in the industrial experiment was better than that in the sintering pot experiment,but their patterns were consistent.When urea is used as an inhibitor,the dioxins can be significantly reduced.When a 0.02％ratio of urea was added,a maximum dioxin emission reduction of 79％was obtained.Reducing the chlorine sources also had an obvious dioxin reduction effect,enabling a 69.49％reduction.In addition,when these two technologies were applied simultaneously,a significant emission reduction rate of 92.23％ was achieved.The concentration of dioxins in flue gas dropped to 0.2421 ng TEQ/m3 before desulfurization,which meets the emission standard for dioxins in the final exhaust gas.     

烧结过程二噁英减排技术研究与工业试验

在完成烧结混合料中各组分氯元素分析的基础上,通过工业试验,分别对降低氯源以及阻滞生成这两种烧结过程中的二噁英减排技术进行了验证。工业试验的二噁英减排效果优于烧结锅试验,但规律一致。以尿素为阻滞剂时,二噁英减排效果显著,但存在最优配比。当尿素添加配比达到0.02%时,减排效果最佳,可达79%;降低氯源也具有明显的二噁英减排作用,减排率可达69.49%;同时采取两种技术,减排效果更加显著,减排率达92.23%,脱硫前烟气中二噁英浓度降至0.2421 ng TEQ/m^3,已可满足最终排放废气中二噁英的排放标准。     

Decrease in levels and body burden of dioxins, dibenzofurans, PCBS, DDE, and HCB in blood and milk in a mother nursing twins over a thirty-eight month period

This paper presents measured dioxin, dibenzofuran, PCB, DDE and HCB blood and milk levels and estimated body burdens in a mother who nursed twins for thirty-eight months. A total of thirteen milk samples and three blood samples were collected and analyzed. Measured PCDD and PCDF levels in milk decreased from 309 and 21 ng/kg (ppt) to 173 and 9 ng/kg, respectively, between March 1993 and September 1995. Based on the decrease in breast milk dioxin levels, we estimate that the nursing mother reduced her dioxin body burden from 310 to 96 ng dioxin toxic equivalents (TEQs), or approximately 69%. In two and one half years the level of HCB in the mother's milk decreased from 10.7 to less than 1.8 ng/g (ppb), the level of DDE decreased from 246 to 46 ng/g and the total level of non-coplanar PCBs decreased from 285 to 63 ng/g, on a lipid basis. We estimate that the twin's consumption of dioxins, dibenzofurans, and coplanar PCBs from breast feeding was approximately 115 ng TEQ per twin.     

Relationships between dioxins in soil, air, ash, and emissions from a municipal solid waste incinerator emitting large amounts of dioxins

The Columbus Municipal Waste-to-Energy (Columbus WTE) facility in Columbus, Ohio, began operation in June, 1983 and ceased operation in December, 1994. During its operation, it was estimated to have released nearly 1,000 grams of dioxin Toxic Equivalents (TEQs) per year. This compares to a 1994 estimate of 9,300 g TEQ/yr from all sources emitting dioxins into the air in the United States (EPA, 1994), and to total releases of dioxins near or below 1,000 grams TEQ/Yr for England (Eduljee and Keyke, 1996), Belgium (Wevers and De Fre, 1995), and West Germany (Fiedler and Hutzinger, 1992). Because of the magnitude of emissions from this single source, studies were undertaken to evaluate the impacts to air and soil near the incinerator. This paper presents analyses evaluating dioxin concentrations and profiles in four media: stack gas, ambient air within 3 km of the incinerator, soil samples up to 8 km from the incinerator, and incinerator ash. Principal findings include: 1) an "incinerator signature" profile, as defined by stack gas emissions, was found in the ash and in subsets of the air and soil matrices, 2) soil concentrations declined from directly outside the incinerator property to the city at large, 3) an urban background soil concentration of dioxin Toxic Equivalents (TEQs) was estimated at 4 pg/g, while concentrations generally within 2 km of the incinerator ranged from 4-60 pg TEQ/g, 4) an urban background air concentration was estimated at 0.05 pg TEQ/m3, while air concentrations at a specific location about 2 km in the downwind direction of the incinerator had concentrations of 0.17 and 0.35 pg TEQ/m3 during two sampling dates, 5) analysis of the soil monitoring data in combination with the stack test data suggests that less than 2% of emitted dioxins can be found in the soil near the incinerator, and 6) principal component analysis suggests that the fraction of total concentration of OCDD is the single feature explaining most of the variation of all concentration profiles. This paper discusses these and other findings, and their implications.     

Dioxins, dibenzofurans, dioxin-like PCBs, and DDE in U.S. fast food, 1995

Food, especially dairy products, meat, and fish, is the primary source of environmental exposure to dioxins in the general population. Little data exists on dioxin levels in the popular and widely consumed "fast foods". Data presented in a previously published pilot study was limited to measuring only the levels of dioxins and dibenzofurans in three types of U.S. fast food. This study adds to the previous paper by presenting data, in addition to dioxins and dibenzofurans, on the closely related dioxin-like polychlorinated biphenyls (PCBs), and the persistent metabolite of DDT, 1,1-dichloro-2,2-bis (p-chlorophenyl) ethylene (DDE), in four types of popular U.S. fast food. These include McDonald's Big Mac Hamburger, Pizza Hut's Personal Pan Pizza Supreme, Kentucky Fried Chicken (KFC) three piece original recipe mixed dark and white meat luncheon package, and H?agen-Daz chocolate-chocolate chip ice cream. Dioxin plus dibenzofuran dioxin toxic equivalents (TEQ) ranged from 0.03 to 0.28 TEQ pg/g wet or whole weight for the Big Mac, from 0.03 to 0.29 for the Pizza, from 0.01 to 0.31 for the KFC, and from 0.03 to 0.49 TEQ pg/g for the ice cream. Daily TEQ consumption per kilogram body weight (kg/BW), assuming an average 65 kg adult and a 20 kg child, from one serving of each of these fast food ranged between 0.046 and 1.556 pg/kg in adults whereas in children the values were between 0.15 and 5.05 pg/kg. Total measured PCDD/Fs in the Big Mac, Personal Pan Pizza, KFC, and the H?agen-Daz ice cream varied from 0.58 to 9.31 pg/g. Measured DDE levels in the fast foods ranged from 180 to 3170 pg/g. Total mono-ortho PCB levels ranged up to 500 pg/g or 1.28 TEQ pg/g for the KFC and for di-ortho PCBs up to 740 pg/g or 0.014 TEQ pg/g for the pizza sample. Total PCB values in the four samples ranged up to 1170 pg/g or 1.29 TEQ pg/g for the chicken sample.     

Influence of short-term dietary measures on dioxin concentrations in human milk

Breast-feeding may expose infants to high levels of toxic chlorinated dioxins. To diminish intake of these lipophilic compounds by the baby, two diets were tested for their ability to reduce concentrations of dioxins in human milk. The diets were a low-fat/high- carbohydrate/low-dioxin diet. (about 20% of energy intake derived from fat) and a high fat /low-carbohydrate/low-dioxin diet. These diets were tested in 16 and 18 breast-feeding women, respectively. The test diets were followed for 5 consecutive days in the fourth week after delivery. Milk was sampled before and at the end of the dietary regimen, and dioxin concentrations and fatty acid concentrations were determined. Despite significant influences of these diets on the fatty acid profiles, no significant influence on the dioxin concentrations in breast milk could be found. We conclude that short-term dietary measures will not reduce dioxin concentration in human milk.     

除尘灰水洗对烟气颗粒物组成和二噁英的影响

为研究除尘灰配入烧结对烟气颗粒物组成和二噁英的影响,利用水洗方式对烧结除尘灰进行除杂改性,然后采用烧结杯测定改性前后配入对烧结矿性能的影响,并通过撞击式颗粒物采样器和二噁英采样器对烟气污染物进行采样分析,研究改性前后配入烧结对颗粒物组成碱金属和重金属含量以及烟气二噁英和前驱体物质排放量的影响.结果表明:烧结除尘灰中的K和Cl在水洗除杂改性过程中被有效去除,除杂后的除尘灰配加烧结有助于改善烧结矿粒度组成、减少烟气颗粒物和二噁英排放浓度;K组成在烧结颗粒物排放中占有较高比例,远高于金属Na、Pb和Zn的含量,且在粒度较细的细颗粒物中占比更高,水洗除杂后配入烧结可显著降低烧结配料中的K组成,使得烟气排放的K组成显著降低,进一步降低颗粒物的排放浓度,其中又以1.10~2.10 μm粒度范围的颗粒物和K组成的减排比例最高;烧结原料Cl组成和烧结过程中的有机前驱体氯苯、多氯联苯是烟气二噁英生成的重要诱因,除尘灰水洗在降低Cl组成的同时也显著降低烟气前驱体多氯联苯排放量达40%,有利于降低烟气中二噁英的排放浓度.      

Clinical laboratory manifestations of exposure to background levels of dioxins in the perinatal period

The effects of exposure to low levels of dioxins in infants (intrauterine and via breast milk) were studied. In a group of 35 babies, specially selected, laboratory tests were performed in cord blood and in blood sampled at 7 days and 11 weeks of age. The outcome of these laboratory tests was related to dioxin concentrations in milk fat and cumulative dioxin intake. At 11 weeks of age, alanine aminotransferase and aspartate aminotransferase activities in plasma were significantly related to cumulative dioxin intake. A significant negative relation was found between platelet count and cumulative dioxin intake. The results of this study suggest that exposure to background levels of dioxins, both intrauterine and via breast milk, may have effects in newborns.