分馏塔超温运行安全性分析

某炼油厂催化裂化车间分馏塔下部油气入口温度由原设计的480℃提高到525℃,因此需对其超温运行的安全性进行分析。用常规强度计算方法和有限元法对塔体和局部区域进行了应力分析计算。计算结果表明,强度足够,结构安定。但分馏塔长时间处在油气入口温度525℃的条件下运行,塔体20g钢材的金相组织会逐渐发生变化,化学性能会下降,蠕变损伤不断积累。因此,该塔再继续服役一个检修期后,应对高温段塔体内壁进行硬度测定和金相复膜分析,以确定能否继续使用。     

产品分馏塔风致开裂失效分析及横风向共振

使卡曼旋涡脱落的频率等于塔设备自身固有频率,以此来求解得塔设备发生横风向共振时的临界风速,确定产品分馏塔(位号:C-302)在强度计算时需要计入横风向载荷。经对该塔体上裂纹的开裂位置、裂纹处金相和断口等特点分析后,认定该塔所产生的裂纹为横风向作用下产生的疲劳开裂,并从塔设备的强度、结构、制造、现场施工等方面出发,提出抵抗横风向共振的措施。     

分馏塔在不移位情况下对底部筒体更换

某公司重油裂解装置分馏塔在试压过程中出现塔体下部筒体立焊缝出现破裂并带动上下两块壁板受损现象,裂缝位置在塔底上方约10m处,对裂纹周边塔体母材经过力学性能试验未发现异常,符合要求。考虑施工成本与周期,决定对在分离塔不移位的情况下对开裂的3层筒体进行更换。对塔体破损部分进行结构加固,防止塔体在维修过程中垮塌,通过载荷计算,在最恶劣的载荷工况下,采取12根钢管立柱的加固方案,计算的强度和稳定性为116MPa,能满足筒体91.1MPa的需求。在加固措施安装完成后,按照一定顺序对壁板逐块更换,并按设计要求对焊缝进行100%无损检测,立式水压试验0.483MPa合格,保证设备能安全运行。     

基于正交试验的输油管道压降敏感性分析

多相混输管道的压降计算是油气集输管道设计和生产运行方案制定的基础。明确影响管道压降的主要因素及其敏感性,对管道设计及运行方案的优化具有重要意义。根据塔河油田集输管网实际运行情况,以沿程百米压降为目标函数,分析了原油黏度、管道管径、液相含水率及管道入口温度(管道入口处油气水混合物温度)对混输压降影响程度。选择Beggs-Brill压降模型,并用实测数据拟合当量表观黏度,对模型进行修正,利用修正后的模型进行正交试验计算。通过对正交试验结果的极差分析,可知各因素的影响程度为:管道入口温度管道内径液相含水率原油黏度。可为输油管线结构设计和运行方案提供参考。     

加氢精制装置分馏塔顶油气线的管道设计

在加氢精制装置管道设计中,分馏塔顶油气管线是具有代表性的重要管道。文章从平面布置、管道设计、应力分析和支吊架设置等方面对分馏塔顶油气管线进行了分析比较。对分馏塔顶油气管线的管道设计优化和支吊架的合理设置,可以降低管道对设备嘴子的受力,提高该管系及设备的安全性。     

延迟焦化装置防结焦技术改造

针对焦化装置实际运行过程中存在的焦炭塔顶部油气携带焦粉、分馏塔底部管线及其过滤器结焦等问题,进行技术分析,并采取切实可行的技改措施,解决了焦炭塔顶部油气携带焦粉问题,缓解了分馏塔底部管线及其过滤器的结焦,产生了可观的经济效益,为装置的安全长周期运行夯实了基础。     

重油催化裂化装置结盐原因及应对措施

分析了在重油催化裂化装置中,分馏塔结盐的根本原因是反应生成的氨盐和HCl与混有少量水蒸气的油气在上升过程中温度逐渐降低,当温度达到此压力环境下水的露点时,就会有凝结水产生,形成的氯化铵溶液沉淀析出塔盘上,堵塞塔盘,从而使塔盘压降逐渐升高。利用原料电脱盐技术,可使催化原料中所含氯盐减少,达到减轻分馏塔结盐目的;重点介绍了分馏塔在线技术,即从分馏塔冷回流系统注除盐水,至柴油系统水洗出,从而带走结盐杂质,达到去除分馏塔所结盐分。电脱盐技术及分馏塔在线水洗技术可以有效遏制分馏塔结盐现象,从而保证装置正常生产。     

乙烯装置急冷油系统稳定运行分析

针对乙烯装置急冷油系统运行难点进行分析,对引起汽油分馏塔的聚合物堵塞原因进行总结,对汽油分馏塔内的聚合物堵塞过程进行分析,指出聚合组分浓度和塔内温度是汽油分馏塔聚合堵塞的关键因素,对急冷油系统的焦粉颗粒细小的原因进行分析,提出了焦粉清除的有效方案.并指出了在运行期间急冷油系统需要关注的重要参数点.     

延迟焦化装置焦炭塔顶油气管线的管道设计

延迟焦化装置中的焦炭塔顶油气管线是多工况的复杂管道系统,其设计的合理与否直接影响到整个焦化装置的运行。焦炭塔顶油气管线的设计不但与焦炭塔、焦化炉及分馏塔的平面布置分不开,而且管道的选材、应力分析、支架设置、操作检修措施也决定着油气管线的设计,配管的优劣会直接影响装置的运行。     

现场金相分析技术应用于海上锅炉检验

锅炉是海上油气开采过程中的重要设备，使用过程中需承受较高的温度，长期运行易引起材质劣化。利用便携式金相分析仪可以直接和材料上进行取样、观察并拍摄金相组织照片，通过对材质的组织结构进行分析，判断其劣化程度，为锅炉的安全状况评定提供依据。     

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.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

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.     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。