克拉2气田乙二醇再生装置回流泵密封失效分析和解决措施

磁力泵由于结构简单、无机械密封点、维修方便等优点而广泛用于油气化工行业,主要用于清洁液体介质输送。在克拉2气田天然气处理厂乙二醇再生装置内,磁力泵作为回流泵用于乙二醇再生回流液输送,由于介质含杂质而出现轴承磨损造成密封失效,影响到装置平稳生产。在统计分析该回流泵历年运行状况,得出磁力泵轴承磨损加剧和密封失效的原因,结合工艺流程提出在回流泵入口改造增加手摇式过滤器,将磁力泵替换为立式屏蔽泵,并修订回流泵维修保养制度的解决方案,实现了装置平稳生产和机械完整性管理目标。     

屏蔽泵轴承磨损破碎故障分析

中原油田石油化工总厂液化气后处理装置脱乙烷塔回流泵使用的屏蔽泵,在开工运行两年后出现了轴承磨损破碎现象,针对故障进行了原因分析,提出了防范措施。     

高温分离型屏蔽泵故障分析及解决办法

兰州石化乙苯装置高温分离型屏蔽泵P-202运行中故障频发,为保证该机泵能够平稳运行,结合该屏蔽泵运行工况对机泵的径向力、轴向力进行分析,找出故障产生的原因,通过调整运行工况、采取改进措施,最终达到平稳运行的目的。     

屏蔽泵故障与处理方法

对屏蔽泵在实际生产中遇到的故障：泵体高温、电机故障、泵振动杂音,进行故障分析。根据生产中遇到的实际问题,指出屏蔽泵操作要点。同时,在装置正常生产中,我们要分析设备出现故障的原因并控制检修质量。只有屏蔽泵长周期运行,才能保证生产装置的平稳生产。     

屏蔽泵的故障分析与解决措施

屏蔽泵是由屏蔽电机和泵组合的密封整体,具有无泄漏的优点,适合输送易燃、易爆、剧毒、易挥发的液体。根据我厂发泡剂生产单元的输送介质,主要为异戊烷,具有易燃、易挥发的的特点,也选择屏蔽泵作为主要的输送泵。本文通过对生产装置中屏蔽泵使用中存在的问题以及产生的故障进行归纳总结,对故障产生的原因进行分析,并在维护中提出相应的解决措施,以保证屏蔽泵长期平稳运行。     

海密梯克屏蔽泵,德国品质 持续为炼油行业提供液体输送解决方案

<正>海密梯克屏蔽泵自动水力平衡轴向力,采用哈氏合金定子屏蔽套,经过特殊工艺滚压成型,精度高、品质好,无焊接缺陷,导磁率高,抗腐蚀性强;滑动轴承材质采用晶体碳化硅(SSIC,SIC30),强度高,耐磨性好,抗腐蚀性强,使用寿命是石墨轴承的10倍以上;与带机械密封的泵相比,平均故障间隔时间长,磨损和维修率低,总运行费用低;高压内循环,不需要外接排气管。广泛应用于烷基化装置、硫磺回收装置、减压蒸馏装置、加氢装置、加氢裂化装置、烃抽提装置(苯)、     

永磁屏蔽泵在乙烯装置的应用

低温甲烷泵是乙烯生产装置深冷分离技术中的关键设备.原工艺技术专利商针对该泵输送的介质具有介质轻、温度低、易燃易爆等工艺特性,选择了以甲醇为密封介质带压密封罐结构的密封形式.运行以来,该密封频繁失效,造成冷箱甲醇冻堵,乙烯损失严重,多次进行改造和试用,效果不佳.借装置升级改造时机,换型为永磁屏蔽泵,有效地解决低温甲烷泵机...     

己内酰胺装置无泄漏泵选型浅析

己内酰胺生产系统中涉及的化工原料多为强腐蚀性、有毒有害、易燃易爆的介质,运行中对无泄漏的要求高于一般化工产品,无泄漏泵(主要包括磁力泵和屏蔽泵)的选型尤为关键。结合兖矿鲁南化工有限公司拟建300 kt/a己内酰胺装置工艺流程的特点,简介磁力泵和屏蔽泵的工作原理,对比分析磁力泵和屏蔽泵之结构参数、性能参数、采购成本、运行维护和故障处理等方面的优缺点,总结国内部分己内酰胺及类似产品生产装置内无泄漏泵的选型情况,并对己内酰胺装置之氨肟化系统和己内酰胺精制系统的无泄漏泵选型提出建议。     

液下屏蔽电泵在氟化氢领域的应用

输送无水氟化氢的液下屏蔽泵常发生泵被卡死、电流偏高、打不起流量等故障,分析了输送无水氟化氢的液下屏蔽泵产生故障的原因,并进行了轴承、轴套、推力盘等相应的改造,保证了屏蔽泵的长周期稳定运行。     

屏蔽泵在醋酐系统中的应用及故障分析

介绍了屏蔽泵的基本结构及特点。详述了屏蔽泵常见的轴承碎裂、出现汽蚀现象,诱导轮叶片断裂、轴套烧结,运转时间短、泵出口压力下降,流量达不到泵的设计要求等方面故障的原因及排除方法。根据屏蔽泵的汽蚀现象、产生原因及泵不同流量时与装置汽蚀余量的关系,提出了解决汽蚀问题的方案。     

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.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.