关于净化系统液氮洗工序裸冷问题的探讨

介绍了液氮洗工序裸冷的工艺流程;简述了液氮洗裸冷的工艺原理;阐明了液氮洗裸冷过程的操作要点;分析了液氮洗裸冷的监测数据。     

浅谈低温液氮洗装置操作维护

煤制合成氨工艺中关于净化气中CO脱除一般选择低温液氮洗技术,但低温液氮洗工艺工作条件苛刻,对工艺操作、设备维护要求较高,本文就我公司液氮洗装置出现的问题及正常维护相关工作进行分享。     

大型合成氨装置液氮洗工艺流程的优化研究

液氮洗工艺在合成氨系统中应用效果良好,同时具备经济性、环保性特点。液氮洗工艺流程包括冷却、洗涤、换热等,装置压力、合成气组成差异,导致工艺流程也有所不同。本文对大型合成氨装置液氮洗工艺流程进行分析,结合具体案例对液氮洗工艺流程进行优化,对比工艺优化后系统应用的成效进行对比分析,工艺具有良好的经济效益,运行过程稳定,满足高负荷运转的基本需求。     

液氮洗尾气回收对液氮洗系统运行的影响及对策

山西中煤平朔能源化工有限公司300kt/a合成氨装置液氮洗系统采用法液空公司工艺包,在制取氨合成原料气的同时副产LNG,设计上将液氮洗尾气提压至3.2MPa后返回变换系统予以回收(传统上液氮洗尾气直接用作燃料气).实际生产中,液氮洗尾气回收后,变换系统、低温甲醇洗系统工况正常,但对液氮洗系统的影响较大,表现为同等生产负...     

脱除合成气中微量CO的方法探讨

介绍了脱除合成气中微量CO的常用方法。通过对低温甲醇洗串甲烷化工艺和液氮洗工艺的比较,说明大型合成氨装置采用液氮洗脱除微量CO具有一定的优势。     

常温进料液氮洗工艺的开发与应用

针对某厂液氮洗工艺进行改造,进行常温进料,突破原料气来自低温甲醇洗的限制。提出了3种改良方案,分别为减少板翅式换热器数量(方案Ⅰ、Ⅱ)和增设甲烷回收装置(方案Ⅲ),以达到与甲醇洗工艺解偶联、节约设备成本、提高经济效益等目的。使用Aspen Plus和Aspen Process Economic Analyzer软件进行模拟优化,结果显示,常温进料液氮洗工艺及其改良方案均符合工艺要求,方案Ⅰ可节约成本达45.78%,方案Ⅲ可回收甲烷达99.16%,为常温进料液氮洗工艺在实际生产中应用指明方向,为优化工艺设计、节约设备成本、提高经济效益提供理论指导。     

国电“3052”项目液氮洗装置开车过程中的问题及解决

1概述 我公司“3052”项目净化装置包括低温甲醇洗、液氮洗、甲烷转化3个工序,是国内首套鲁奇气化流程配套类林德工艺的液氮洗装置。液氮洗装置由中国寰球化工工程公司设计,冷箱及冷箱内部的换热器、分离器以及氮洗塔等主要设备由杭氧股份有限公司提供并负责安装。液氮洗装置自2011年10月投人生产试车以来,发生了冷箱冻堵和氮洗塔漏液等问题,为后工序试车造成了障碍。     

PR方程用于液氮洗工艺物性的计算

采用PR方程对低温液氮洗工艺中所涉及物质的纯组分物性、二组元相平衡数据以及三元相平衡数据进行了模拟计算。结果表明:PR方程用于计算液氮洗组分的热力学性质时,对H2定压比热容的计算存在较大偏差,对N2与CO之间的相平衡数据计算存在一定偏差。针对偏差进行数据回归后的物性方法,计算三元相平衡数据的与文献数据有较好的吻合,可用于低温液氮洗深冷工艺的模拟。     

甲醇系统进水引起的事故简析

山西化肥厂合成氨装置是我国目前唯一的以鲁奇气化炉为龙头的制取合成氨的大型合成氨装置。其净化流程采用低温甲醇洗和液氮洗工艺,低温甲醇洗主要脱除硫化物和CO_2,液氮洗脱除CO和CH_4,脱除下来的CH_4再经转化制取合成原料气—H_2。流程     

浅谈低温液氮洗装置运行问题与操作维护

结合液氮洗装置运行中出现的问题,简述液氮洗工艺流程,总结液氮洗装置存在的主要问题,介绍液氮洗装置的日常维护经验。     

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。