背压式汽轮机管道的设计与分析

背压式汽轮机是一种高速旋转式原动机,为压缩机提供动力,其将蒸汽的热能转换成机械能,这类设备管嘴的受力十分敏感。本文通过某装置中背压式汽轮机进汽及排气管道的布置,支吊架的选型及对相关管道应力的计算,给此类汽轮机管道布置提供参考。     

CAESARⅡ软件在汽轮机蒸汽管道布置中的应用

利用基于有限元的管道应力分析软件CAESARⅡ对汽轮机蒸汽管道进行建模与应力分析,通过对三种不同支吊架设置及管道走向的方案进行比选,得出了汽轮机蒸汽管道的最优布置方案。该方案不仅满足NEMA SM23标准的要求,更为同类型管道的布置提供借鉴。     

汽轮机主蒸汽管道的多工况应力分析

利用管道应力分析软件CAESAR Ⅱ针对汽轮机主蒸汽管道进行多工况应力分析,通过对操作工况、设计工况、暖管1工况、暖管2工况、安装工况等多种工况进行模拟与计算,得出了汽轮机主蒸汽管道的最恶劣工况为汽轮机冲转前的暖管2工况,该工况的提出与应力分析方法对深入探索汽轮机蒸汽管道的布置具有一定的借鉴意义.     

汽轮机进口管道应力分析

利用CAESARII应力分析软件程序对汽轮机进口管道进行了应力分析,根据ASMEB31.3《工艺管道》标准要求进行应力校核,管口受力按照NEMA SM23进行核定,进而对汽轮机进口管道的布置提出一般性解决方案。     

背压式汽轮机管道柔性设计分析

石油化学工业使用汽轮机做驱动机是降低能耗的有效途径，合理的管道设计是实现汽轮机安全运行的保障。由于对汽轮机管口允许的力与力矩具有严格的要求，这给管道设计带来非常大的难度。通过总结工程实例，利用CAESAR II应力分析软件对汽轮机进出口管道进行了应力分析，通过调整支吊架的形式和管道布置方式使汽轮机管口受力满足NEMA SM23标准的要求，总结了减小汽轮机管口受力的一些方法，为汽轮机同类蒸汽管道设计提供参考。     

汽轮机蒸汽进口管道应力分析

利用CAESARII管道应力分析软件对汽轮机蒸汽进口管道进行应力分析,并针对可能存在的几种工况进行模拟分析与计算通过调整支吊架及弹簧架的位置和形式,不断优化管道布置,使得汽轮机管口综合受力和综合力矩满足设备厂家提出的许用荷载。提出了特殊工况下的模拟和计算方法,以及减小管口受力的一些方法。     

高压抽注凝汽式汽轮机主蒸汽管道的应力分析

介绍了大型合成氨尿素项目中高压抽注凝汽式汽轮机主蒸汽管道的特点,为了保证高温高压管道的安全稳定运行及此类汽轮机的顺利开车,采用CASER II应力分析软件,对此类汽轮机的高温高压管道的配管进行了应力分析和优化设计,通过合理设置支吊架以及增加管系柔性,使汽轮机管口受力、管系的应力及位移满足标准规范的要求,并对弹簧的选型进行了论述。     

汽轮机高压蒸汽管道配管设计浅析

通过分析汽轮机管口受力要求及高压蒸汽管道的工况,得出汽轮机蒸汽管道布置的基本原则,在此原则指导下,介绍了几种典型的汽轮机管道布置方式。     

汽轮机蒸汽进排汽管道的优化设计

阐述了某空分装置空气压缩机汽轮机在正常运行过程中出现的振动值偏高以及检修时发现轴端汽封的磨损,利用CAESAR II软件对现场布置的进、排汽管道进行应力分析,发现汽轮机进、排汽管口的力和力矩均超过厂家设计值的要求,由此确定汽轮机转子的振动值偏高和汽封磨损是由于进排汽管道热膨胀对汽轮机缸体的作用力而引起。采取对进、排汽管道增加自然补偿或膨胀节来增加管道的柔性,减小管道作用于汽轮机管口的力和力矩,消除了汽轮机的振动值偏高的问题。     

石油化工压力管道柔性设计的浅析

管道柔性的好坏通常与管道应力有关,目前对于管道柔性与应力分析问题的研究越来越多。在这一背景下首先阐述了石油化工管道应力分析方法,然后分析了管道应力的设计要求,之后说明了管道应力分析步骤及管道布置调整问题,最后通过几种管道应力分析设计,对石油化工压力管道柔性设计要点进行说明,希望能为相关人员带来一定的启示,提高压力管道的设计与布置水平。     

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。