A110—1H型预还原氨合成催化剂的工业应用

催化剂生产厂采用最佳条件对氨合成催化剂预先进行还原处理，可获得最佳的催化剂活性，并可为氨厂赢得有效的生产时间，经济效益显著。本文拟以小型以及日产千吨的大型氨厂为例，说A110－1H型预还原氨合成催化剂的活化、运转及其经济效益进行分析评价。     

ZA—3型氨合成催化剂升温还原小结

我厂是年产8万吨合成氨的中氮厂，合成氨系统为两套并联使用。新合成塔内径为1000mm，采用内部换热三套管内件，中置锅炉。旧合成塔内径为800mm，采用双层并联扁平管并流内件。今年旧合成塔更换催化剂时选用活性温度低的ZA－3型催化剂，代替以往使用的A110－1型催化剂。为了不影响生产，在维持新塔满负荷生产的情况下，对旧塔进行升温还原。现将此次催化剂升温还原小结如下。1工艺流程及主要设备简况1．1工艺流程我厂氨合成的工艺为传统流程，即合成塔出口气经水冷一次分氨，循环气加压后在滤油器中与新鲜气混合除油水，冷凝塔、氨蒸发器…     

A110-1-H预还原氨合成催化剂的应用

1　概况我厂有两套 (Φ80 0mm ,Φ10 0 0mm)氨合成系统 ,操作压力P≤ 3 1.4Mpa ,属中压合成氨 ,内件采用双层并联扁平冷管并流型流程。A110— 1—H型预还原型氨合成催化剂 ,在我公司分别于一九九八年 ,Φ80 0mm塔 ,二 0 0 0年Φl0 0 0mm塔 ,二 0 0三年Φ80 0mm塔 ,三次装填于绝热层中 ,实践证明与以往全炉装填A110— 1型全氧化态相比 ,使我公司在氨合成催化剂的工作上了一个新台阶。2　采用A110— 1一H型氨合成催化剂的背景 :2 .l　流程简介 :双层并联扁平冷管并流型流程中 ,循环气从主线经与出塔气换热后与付线来气体一起经中心管电炉丝…     

常用氨合成催化剂的反应速率常数和最佳活性使用温度

根据常用的6种氨合成催化剂的本征活性测定数据，用焦姆金动力学方程回归得到反应速率常数与温度的关系。利用所得反应速率常数，模拟了这6种氨合成催化剂在中型氮肥厂φ1000mm三套管氨合成塔的反应结果。从催化剂的使用温度来看，从A106、A109、A110－1、A110－2、ICI74－1到ZA－5最佳活性使用温度不断降低。     

A110-1型氨合成催化剂升温还原总结

叙述了A110－1型氨合成催化剂的装填、升温还原的原则及过程,并与其它类型催化剂升湿还情况进行比较,总结了使用效果。     

A301型氨合成催化剂应用小结

总结了A301型低温、低压、高活性氨合成催化剂在Φ1 800 mm合成塔的实际应用情况。介绍了合成系统的配置、工艺流程以及催化剂的装填情况,通过催化剂升温还原状况和生产过程运行数据的比较,对A301型氨合成催化剂的应用效果进行了评价,充分反映出A301型氨合成催化剂活性高、使用压力低、氨产量大等优良的性能特点。     

A202型低温氨合成催化剂的工业应用

本文报导了A202型低温氨合成催化剂的工业应用情况。工厂使用表明,该催化剂的各项性能优于 A201。在同等条件下,氨合成率比A110 系列提高7%~17%。比A201提高4%~10%，并具有低温、低压活性高、耐热性和抗毒性好的特点,是一种节能、高效的新型氨合成催化剂。     

A2O3型低温氨合成催化剂的分段升温还原

0 前言 南阳德润化工有限公司已形成年产80kt／a合成氨联醇生产能力，现有2套φ800mm并联氨合成系统，均采用JR型内件，每塔催化剂筐有效容积4．11m^3。由于前几年催化剂选型较杂乱、更换频繁，造成氨合成系统压力偏高。经慎重考察论证，从2001年起我公司开始使用A203型低温氨合成催化剂，到目前为止氨合成系统运行良好。现就该催化剂的升温还原进行总结。     

浅谈Ф1500氨合成塔内件的改进及应用

对氨合成塔内件使用过程中存在的塔壁超温、同平面温差大、轴向温升低、3#冷激存在冷管效应等问题进行分析,针对生产中出现的情况提出改进措施并实施,同时采用新型的低温高效A301型催化剂及A110-2型氨催化剂,对催化剂快速彻底还原,解决了合成高压圈原有的问题,稳定了操作,提高了产量,同时降低了能耗,并对该塔型在今后的应用提...     

A110—2氨合成催化剂在我厂的应用

A110—2型氨合成催化剂是一种高活性、低温性能好、容易还原的高效合成催化剂。1982年10月,我们在单管并流式轴向合成塔中装填了A110—2型合成催化剂。一、设备状况和装填情况: 我厂是老三千吨型厂。原四版设计,合成系统于80年由φ450合成塔改为φ505合成塔,其余设备基本未加改变。从文献上知道A110—2型氨合成催化剂活性好、氨产率高、反应热大,浙江化工学院为这种催化剂重新设计了一个单管单环折流式合成塔内     

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.     

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.     

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.     

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.