燃煤电厂湿法烟气脱硫废水零排放工艺研究进展

燃煤电厂湿法烟气脱硫废水具有弱酸性、氯离子浓度高、易结垢等特点。针对上述特点,国内采用不同方法处理脱硫废水,本文介绍了低温烟气蒸发工艺、旁路烟道蒸发工艺、旁路蒸发塔工艺、正渗透MBC浓缩结晶工艺以及低温浓缩高温干燥工艺的流程,并讨论了几种工艺的优劣。此外介绍了一种处于研究阶段的浓缩固化脱硫废水零排放工艺,旨在为燃煤电厂脱硫废水零排放工艺改造提供参考。     

燃煤电厂脱硫废水零排放技术研究进展

燃煤发电会产生大量的含硫危害气体,烟气湿法脱硫工艺是燃煤电厂最常使用降低烟气污染的技术,脱硫效果显著,但湿法脱硫产生的废水会造成二次污染,须要进行特殊处理.从烟气脱硫废水的处理现状入手,简述了脱硫废水产生来源、水质特点及其危害,重点介绍了基于蒸发结晶技术和烟气余热干化技术的脱硫废水零排放工艺路线,分析了其核心技术原理及优缺点,比对了其应用效果,并从知识产权角度分析了零排放的技术主体,并展望了脱硫废水零排放技术的发展趋势.     

高镁型脱硫废水零排放处理技术研究

国内燃煤电厂湿法烟气脱硫工艺产生的脱硫废水具有pH呈酸性、成分复杂、硬度高、TDS高等特点。尤其当石灰石原料中含有较多白云石时,脱硫废水中镁离子高达10 g/L以上,属于典型高镁型脱硫废水。以国内某燃煤电厂产生的高镁型脱硫废水为例,提出了一种新型适用于高镁型脱硫废水零排放工艺。主要分为预处理工艺、浓缩工艺、固化工艺三个阶段。其中预处理工艺采用石灰-硫酸钠联合软化工艺去除废水中硬度,生成高品质石膏产品。浓缩工艺采用NF-HSRO膜浓缩工艺进行分盐浓缩减量,废水中TDS可被浓缩至12%～15%,后续固化工艺采用MVR蒸发结晶工艺得到高纯度氯化钠结晶盐,从而实现真正意义的脱硫废水零排放,具有较好的经济效益、环境效益和社会效益,也为其他类型脱硫废水提供了参考及借鉴。     

燃煤电厂脱硫废水零排放处理技术与应用

燃煤电厂生产过程中产生的废气主要采用石灰石—石膏湿法脱硫技术处理,其废水具有含盐量高、腐蚀性强、硬度高等特点;介绍了脱硫废水的水质与排放标准,阐述了烟道蒸发和蒸发结晶技术两种常见零排放技术的原理和工艺流程,并总结了目前该技术在国内外的应用现状。     

燃煤电厂湿法烟气脱硫废水零排放技术进展

燃煤电厂湿法烟气脱硫废水具有含盐量大、腐蚀性强、易结垢等特点,是制约电厂废水零排放的关键因素。从预处理、浓缩减量、末端处理三个方面详细介绍了脱硫废水的处理技术,分析各自的优劣,研究进展,并对烟道蒸发技术进行深入分析。最后通过工程实际案例,为燃煤电厂废水零排放提供了参考。     

燃煤电厂湿法烟气脱硫废水零排放技术进展

燃煤电厂湿法烟气脱硫废水具有含盐量大、腐蚀性强、易结垢等特点,是制约电厂废水零排放的关键因素。从预处理、浓缩减量、末端处理三个方面详细介绍了脱硫废水的处理技术,分析各自的优劣,研究进展,并对烟道蒸发技术进行深入分析。最后通过工程实际案例,为燃煤电厂废水零排放提供了参考。     

燃煤发电厂脱硫废水零排放处理技术

从燃煤发电厂脱硫废水形成机理、危害影响以及主要特点入手,详细分析了当前常用的脱硫废水零排放处理技术,包括蒸发结晶技术、旁路热烟气蒸发技术以及低温烟气旁路蒸发浓缩技术等,最后结合电厂实际情况,提出了脱硫废水零排放处理技术方案,最终取得了良好使用效果。     

燃煤电厂脱硫废水综合处理工艺

针对燃煤电厂采用石灰石-石膏湿法脱硫后的废水含有无机盐、重金属以及悬浮物等污染物的特点,以某电厂废水处理中试为例,介绍了脱硫废水零排放综合处理的新工艺,提出了正渗透或机械式蒸汽再压缩蒸发器(MVR)与烟道余热蒸发结合的处理方案。中试结果表明,回收的淡水经生化或反渗透进一步处理后,实现了COD100 mg/L,SS和NH_3-N的质量浓度分别10、15 mg/L。该工艺适合燃煤电厂废水的综合处理,可有效降低运行成本,实现真正意义上的零排放。     

燃煤电厂脱硫废水零排放技术现状与发展

燃煤电厂脱硫废水存在水质差、水量大、处理成本高等问题,废水处理技术也在不断更新换代。不同电厂其脱硫废水的水质、水量相差较大,处理技术的选择也存在较大区别,为了更科学有效地选择脱硫废水处理技术,汇总分析了目前燃煤电厂脱硫废水处理技术,根据实际案例详细分析各处理技术的优缺点,为燃煤电厂对脱硫废水零排放技术的选择提供参考。研究结果显示,目前燃煤电厂脱硫废水零排放处理技术主要包括脱硫废水的预处理技术、浓缩减量技术、蒸发结晶技术以及转移固化技术,各废水零排放处理技术参差不齐。详细分析了预处理技术中的三联箱法、双碱法,根据废水特点,该预处理环节可省略,以减少投资成本;浓缩减量技术包含膜法浓缩(RO、FO、ED等)和热法浓缩(利用蒸汽浓缩、烟气余热浓缩),膜法浓缩可实现较高的浓缩倍率且系统稳定,但其较高的投资运行成本有待解决;热法浓缩依靠其低成本、高效率逐渐成为主流浓缩技术。蒸发结晶技术利用烟气余热蒸发(旁路烟道蒸发、烟道蒸发),其运行中的腐蚀、结垢问题有待解决;转移固化技术中的水泥化固定技术,不仅能够固定脱硫废水中的高浓度氯离子,同时对废水中的多种重金属离子具有较好的固定效果,该技术对处理产生的终端高浓度含盐水指明去处,其固化体得以二次利用;高浓度氯离子也可制备净水剂,实现废水中盐分的二次利用。同时,提出了脱硫废水处理技术选择的四原则。低成本、低风险、高成效的脱硫废水零排放工艺路线更符合当前企业需求。     

火电厂湿法脱硫废水零排技术研究进展

综述了石灰石-石膏法脱硫废水零排放主流技术工艺,对化学混凝沉淀、电渗析、正渗透、反渗透等预处理工艺和MVR、MED以及烟道蒸发等蒸发结晶工艺进行了简要阐述。脱硫废水零排放的实现主要通过对废水进行预除盐和浓缩减量后,对浓缩废水进行蒸发结晶处理,介绍了脱硫废水零排放改造几种主流技术路线组合,以期为脱硫废水零排放技术的应用和研究提供参考。在选择脱硫废水零排放工艺时,注重处理效果的同时,还应考虑零排放工艺设施的引入,是否产生其他衍生问题,从而影响设备本身以及下游设备的运行维护。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。