如何提高碱液蒸发的生产效益

我厂蒸发工序的生产能力为1.5万t/a,采用三效顺流逆向采盐部分强制循环工艺。 蒸发工序的主要任务是:制取合格的商品液碱及将析出结晶盐化成回收液送盐水工序。它的主要成本有蒸汽消耗、水耗、电耗、中小维修费等,要提高蒸发工序的经济效益还必须加强对自用碱和碱损的管理。 蒸汽消耗是蒸发工序最为关键的消耗指标,从蒸发的传热方程式q/F=α△t     

浓效蒸发器失稳分析及改进设计

我厂烧碱装置规模为8万t/a,电解槽为一套16型石墨槽、一套27型石墨槽。与之匹配的蒸发为三套,即A蒸发年产3万t;B、C蒸发各为年产2.5万t,其中A蒸发为三效五体强制循环工艺设计。该装置浓效蒸发器于1995年10月18日在洗效过程中,突然异响,蒸发罐体产生严重变形,导致其循环管拉     

优化蒸发工艺 降低烧碱汽耗

为满足6万t/a烧碱生产规模的要求,山东滩坊亚星化学股份有限公司改造了原5万t/a烧碱蒸发装置淡碱预热采用板式换热器二级预热工艺;Ⅱ效加热室加热面积由原来的284m2增到384m2;Ⅲ效抽真空管道直径增大;喷射冷凝器规格由Ф1 200增大到Ф1 600;I效加料泵扬程增高了30m.改造后的蒸发系统完全满足6万t/a烧碱生产要求,而且蒸发综合汽耗由原来的3.6t/(t.NaOH)降到3t/(t.     

烧碱蒸发工艺的改造

针对烧碱蒸发系统的生蒸汽压力不稳定、末效真空度低、设备腐蚀严重等问题，将三效顺流强制循环工艺改为三效四体，并更换了循环水泵。工艺改进后，设备运行平稳、腐蚀减轻，末效真空度由0．070MPa提高到0．083MPa，生产能力由4万t/a提高到5万t/a，并对改进后工艺存在的问题提出了改进建议。     

盐泥增浓工艺在隔膜碱蒸发中的应用

隔膜碱蒸发过程中盐的处理是关键问题。我公司原有1套双效顺流蒸发装置,生产能力为年产4万t;1套三效顺流部分强制循环蒸发装置,生产能力为年产2.5万t。1998年4月,我公司为满足用户需要新建了1套旋转薄膜蒸发装置生产45％碱,生产能力为年产2万t。其过滤掉的盐泥由三效顺流部分强制循环蒸发装置(以下简称:新蒸发)进行处理。由于30％液碱蒸至45％过程中产生的盐泥颗粒细、粘度大、含碱量高、处理集中,离心机(双级     

优化蒸发工艺 提高生产能力

内蒙古三联化工股份有限公司氯碱厂为满足6万t/a烧碱装置的生产能力，对蒸发工艺进行了优化：增加1台50m^2的螺旋板预热器；采用了目前较先进的加料泵及采盐泵；对离心机运行的控制也进行了改进，由原来使用的各效冷凝水作为冲洗水，改为使用一次水为冲洗水，冲洗时间由原来的10s改为2－4s，并对离心机各个部件也进行了更换；凉水系统进行了技术改造；洗效周期及洗效方法进行了完善。蒸发工艺经改造后，生产能力达到了公司扩产的要求，一次水单耗由原来的2．5万t/月降到5kt／月，并且环境得到了改善。     

烧碱蒸发工艺现状及节能改造的建议

分析了隔膜法烧碱装置三效顺流部分强制循环蒸发工艺中影响蒸汽消耗和产量的主要因素:蒸汽压力,末效蒸发器真空度,结晶盐、采盐及分离。三效顺流部分强制循环与三效四体两段蒸发工艺存在蒸汽消耗高的问题,建议将生产30%碱液装置改为生产42%或50%的碱液装置,并将三效顺流部分强制循环工艺改造为三效逆流工艺以达到降低汽耗的目的。概述了离子膜法烧碱蒸发及固碱生产技术,分析了离子膜法烧碱蒸发、浓缩工艺采用国产化装置的优势。介绍了蒸发系统真空设备的选型问题,认为真空设备以表面冷凝器加机械真空泵组合为好。     

吉兰泰碱厂25万t/a纯碱装置技术改造

介绍了吉兰泰碱厂 2 5万t/a纯碱装置技术改造情况 ,碱厂通过技术改造后 ,生产能力增加了2 5 % ,年增加产值在 5 0 0 0多万元 ,氨耗及盐耗大幅度下降 ,每年因消耗降低而节约的费用在 5 0 0多万元。技术改造后 ,碱厂设计能力达 2 5万t/a,实际生产能力已达 31万t/a纯碱。     

膜损伤原因及对电流效率的影响

1 国内离子膜制碱技术发展概况我国第一套1万t/a离子膜制碱技术自1986年6月在盐锅峡化工总厂投产以来,到1997年8月,离子膜制碱技术已达104万t/a,占全国烧碱产量的1/5,其中国产化装置设计能力达22万t/a,已有9万t/a投入生产。引进的电解槽技术分别为旭硝子的单极槽,ICI的单极槽,迪诺拉单极槽,旭化成的     

循环水在丙烯腈联合装置运行中的季节性优化节能

中国石化某厂丙烯腈装置最初设计2。5万t／a,经过技术改造后达到4万吨／年;2011年进行“两头一尾”改造,保留原反应部位（流化床反应器至吸收塔）,新建5万t／a的反应部分和8万t／a的精制部分、四效蒸发部分及乙腈部分,并增加一套空压机组和丙烯制冷机组。本文论述了丙烯腈联合装置运行过程中循环水的季节性优化节能。     

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。