乙烯装置中的结焦抑制剂

介绍了烃类裂解制乙烯装置的结焦抑制剂，根据抑制结焦的机理对结焦抑制剂进行了分类，并从技术方面初步探讨了乙烯装置上采用结焦抑制剂的可能性。     

乙烯裂解炉结焦控制技术近况

系统地总结了国内外在控制结焦技术方面的成果和进展，对我国开发结焦抑制技术、提高乙烯装置竞争能力，提出了建议。     

乙烯裂解炉结焦抑制技术进展

综述了近年来国内外乙烯裂解过程中结焦抑制技术研究及工业应用进展;介绍了添加结焦抑制剂、炉管涂覆技术研究、新材料炉管的工业应用;对中国乙烯装置开发结焦抑制技术提出了建议。     

乙烯裂解炉的结焦原理及其抑制方法

乙烯裂解炉的结焦是影响乙烯装置正常运行的一个重要因素,本文依据结焦原理介绍了使用结焦抑制剂、改善炉管材质以及炉管表面处理三种抑制乙烯裂解炉结焦的方法,并着重阐述了国内外抑制结焦的研究现状。     

乙烯裂解结焦抑制剂的研究进展

指出了乙烯工业在石油化工中的重要地位;讨论了炉管结焦给工业生产带来的危害;综述了乙烯裂解结焦抑制技术的进展;探讨了结焦机理;介绍了抑制结焦的技术、结焦抑制剂的种类与发展趋势;对我国结焦抑制技术的发展提出了建议。     

原位涂层抑制结焦技术在燕山乙烯裂解炉上的应用

介绍了原位涂层抑制结焦技术在中国石化北京燕山分公司化工一厂乙烯装置新区60 kt/a乙烯SRT-Ⅳ-HC型裂解炉上的应用情况,应用结果表明:原位涂层技术抑制裂解炉辐射段炉管结焦效果明显,裂解炉运行周期大幅延长,SRT-Ⅳ-HC型裂解炉石脑油裂解运行周期超过230 d。     

乙烯裂解炉及急冷锅炉结焦抑制技术研究进展

当前工业上普遍采用结焦抑制处理的技术防范来减少和杜绝乙烯裂解炉以及急冷炉出现结焦的问题,从而提升生产效率与安全性。立足于现状,文章首先分析了乙烯裂解炉与急冷锅炉结焦的基本原理,其次对抑制乙烯裂解炉结焦技术的发展情况进行了分析,并在最后对抑制急冷锅炉结焦技术的发展进行了解析,希望可以为结焦抑制技术的进步与发展创造条件。     

乙烯裂解炉技术进展

裂解炉是乙烯装置的核心,裂解炉的改进对整个乙烯装置操作的经济性有直接的影响.综述了乙烯蒸汽裂解炉的大型化、炉型结构、炉管材料、抑制结焦技术、急冷锅炉、燃烧器的研究现状.介绍了乙烯裂解炉技术的最新发展状况,提出了我国乙烯裂解炉技术的发展方向.     

表面技术在抑制乙烯裂解炉结焦领域的应用研究进展

分析了乙烯裂解炉炉管表面成分对结焦机理的影响;在此基础上介绍了表面技术在抑制乙烯裂解炉炉管结焦上的应用现状,并比较了各种表面技术的优缺点,展望了表面技术在抑制炉管结焦领域的应用前景以及今后的研究重点。     

乙烯裂解炉结焦抑制剂的研究进展

在乙烯装置中,裂解炉结焦是制约装置运行的重要因素。在裂解原料或稀释蒸汽中添加结焦抑制剂是目前延长装置运转周期较为有效的方法之一。综述了国内外乙烯裂解炉结焦抑制剂的技术进展和发展方向,结合我国乙烯裂解装置的情况,提出应加强结焦抑制剂的研究开发,降低抑制剂的成本,优化工业化加剂方案,提高抑制剂的应用技术水平等建议。     

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.     

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.     

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。