隔膜碱蒸发工艺改进的探讨

天津化工厂为满足10万t／a隔膜烧碱的生产能力，对原双效六体自然循环蒸发工艺进行了改造。改造后的蒸发采用了三效顺流部分强制循环工艺。控制系统采用恒河DCS，调节阀采用模拟量调节阀，进科、过碱、循环全都实现连续进行。离心机采用推科式离心机与卧式刮刀离心机共存的分离工艺。改造中增加了生蒸汽、二次蒸汽去过热增湿系统，使过热度保持在2℃以内，提高各效的传热效率，改造后生产装置汽耗显著下降。     

自动控制技术在烧碱蒸发工艺中的应用

哈尔滨华尔化工有限公司为满足新上项目层状偏硅酸钠的需要，2006年10月将烧碱生产能力扩大1万t／a，总能力达到了5万t/a。为确保蒸发装置稳定运行，提高烧碱产量和质量，对蒸发系统进行了改造，实现了自动控制，稳定了效体液位，提高了蒸发效率，减轻了操作人员的劳动强度，降低了蒸汽消耗。     

离子膜双效顺流蒸发工艺计算

本文采用计算机模拟，以年产２万ｔ离子膜烧碱为例，通过对烧碱蒸发双效顺流工艺的计算，利用最优化方法，得出了生蒸汽量与加热面积的最佳配比；通过计算考察了生蒸汽、加热面积、传热系数和真空度等对生产的影响情况。     

双效蒸发系统深度节能工艺的探索

针对双效蒸发系统末效的二次蒸汽潜热未加以利用的问题,提出一种双效蒸发系统深度节能工艺,并对工艺的节能效果进行定量计算.结果表明,利用末效二次蒸汽作为热源加热空气和废水,再通过空气吹脱对废水进行一定程度的预浓缩,最终可节省8.58％的新鲜蒸汽用量,年节省运行成本约20万元.该工艺操作性强,经济效益好.     

皂化废碱液双效蒸发设计

以10万t/a环己酮生产装置操作数据为基础,结合化工模拟软件计算,开发出高效的双效皂化废碱液蒸发工艺。与单效皂化废碱液蒸发工艺相比,采用双效蒸发工艺处理皂化废碱液,扣除初期建设投资费用,每年可节省费用855.6万元。     

三效顺流强制循环蒸发工艺情况介绍

蒸发在隔膜法制碱过程中占有相当重要的地位,因此如何提高蒸发器的生产强度及降低汽耗一直是氯碱行业十分重视的问题。众所周知,三效蒸发由于蒸汽可多利用一次,蒸汽消耗可比双效蒸发大幅度下降。在当前能源十分紧张的情况下,蒸发工艺由双效向三效转变是势在必行的。一九七九年初,我厂有关单位共同努力开始了蒸发工艺的改革工作,已初见成效。但由于我们的工作做得还很不够,所以只能     

蒸发工段扩建总结

蒸发工段扩建总结抚顺有机化工厂的烧碱蒸发工段，原来采用双效蒸发工艺流程，生产能力为１．５万ｔ／ａ．为了满足扩产２．５万ｔ／ａ生产规模的要求，将原工艺改为三效三体顺流部分强制循环逆向来盐工艺，改后的工艺经生产实践证明，效果较好，现简介如下。１工艺流程（...     

粗磷酸的双效蒸发

在湿法磷酸蒸发工序中用双效蒸发代替单效蒸发,使酸的含量(以 P_2O_5计)从28—9%浓缩至42%,双效蒸发不但减少了所需要的蒸汽量,还可降低最初的温度(225℉),由于比     

脱硫双效蒸发工艺系统改进分析研究

本套脱硫装置采用双效蒸发结晶系统。该套蒸发结晶系统是在负压的情况下,利用新蒸汽通过加热器对浆液进行升温,在分离室闪蒸出饱和蒸汽,冷凝闪蒸汽,从而达到浓缩浆液,产生硫酸铵结晶体。通过对双效蒸发改造,能够使双效运行的方式多样化,一效、二效可串联运行、并联运行及单独运行。使得脱硫装置能够连续运行,以便于在装置运行期间对设备设施进行检维修工作。通过调整一二效运行参数,保障设备安全、长周期稳定运行。从而大大改善脱硫装置目前的运行状况。     

小型化肥厂尿素"六改十"运行总结

在尿素装置设计能力由6万t／a提高到10万t／a的改造中,介绍了采用双塔并联工艺流程和改进尿素合成塔塔板的优越性,分析和论述了中压系统、低压系统、蒸发系统以及相关设备的改进目的和改造方案,结果表明,改造后生产能力达到了16万t／a,日产尿素达到520t／d,吨尿素蒸汽消耗从投产时的1,58t降低到1,3t,吨尿素氨耗从590kg降低到573kg。     

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。