化工用加热炉出口温度控制和热平衡监测系统

将加热介质的入口温度和出口温度相结合,通过预估控制法计算燃气量,采用模糊控制技术评价出口温度,最终实现出口温度的快速调节,同时测量正平衡法参数实现加热炉热效率的同步测算,并设计了一种快速调节加热炉出口温度和测算加热炉效率的自动控制系统.     

糠醛抽出液加热炉出口温度模糊控制

加热炉两路进料量的波动和不平衡，是造成炉出口温度难以控制的主要原因。该方案以出口温度和两路温差为控制对象，以流量调节为主要手段，以操作经验值为参考，编写了BASIC语言程序，应用效果较好。     

多路进料加热炉的控制

总结了加热炉自动控制的各方面 ,包括炉出口温度的控制 ,防止炉管结焦控制 ,炉膛压力控制 ,氧含量控制和加热炉的联锁系统。提出了对多路进料加热炉用热量均衡控制防止炉管结焦的思路 ,并将热量均衡控制方案和流量均衡方案加以比较 ,说明了两种方案的适用条件和优缺点。     

基于PCS的加热炉控制系统设计

以工业上常见的强制通风加热炉为被控对象,分析其工艺流程、动态特性和控制要求,综合考虑安全、节能及环保等目标,设计了加热炉物料出口温度、烟气含氧量、炉膛压力和物料入口流量的控制方案。采用高级多功能过程控制实训系统(SMPT-1000)和西门子PCS7过程控制系统,实施并验证了所设计的加热炉控制系统。控制结果表明,该加热炉系统能很好地满足控制要求。     

多液位与加热炉复合系统的协调控制

多液位与加热炉复合系统是一类具有液位和加热炉支路间的强耦合性及大滞后与非线性等特性的复杂工业过程。针对这类系统的多液位控制与加热炉支路温度平衡控制问题,根据解耦与平衡的思想,提出了一种基于总容量平衡的变周期液位控制的协调控制方法,从结构上实现了多液位控制与支路温度平衡控制的分离,耦合性分析也说明了方法的可行性,最终实现了复合系统的整体协调控制。基于HYSYS流程模拟的仿真实验表明了所提出控制方法的有效性。     

基于分布式偏差的加热炉支路温度一致控制

针对现有集中式温度支路平衡控制存在的问题,提出基于分布式偏差的支路温度一致性控制方案：仅利用相邻支路的温度信息,将各支路与相邻支路的温度偏差作为控制输入,使加热炉所有支路的温度达到一致的同时,确保调节过程中总进料流量不变。由于仅利用了相邻支路的温度信息,使得所提分布式偏差控制方案在大规模支路情形下更显优势。最后仿真实例表明了该分布式控制方案的有效性与可行性。     

加氢装置反应进料炉出口两路温差大分析总结及问题探讨

中海油舟山石化1.7Mt/a馏分油加氢装置运行过程中,原料油加热炉F2101出口两路温度频繁波动,温度偏差多达14℃,造成加热炉热效率大幅下降,并且损害加热炉的平稳运行,对设备不利。通过加热炉运行过程中各相关曲线分析,查出具体原因后,对加热炉各火嘴配风量、燃料气量及燃烧情况进行调整,使加热炉出口两路温差得到有效控制,并且在后续3个月运行期间加热炉出口两路温差平稳地控制在3℃以内。     

基于分布式偏差的加热炉支路温度一致控制

针对现有集中式温度支路平衡控制存在的问题,提出基于分布式偏差的支路温度一致性控制方案:仅利用相邻支路的温度信息,将各支路与相邻支路的温度偏差作为控制输入,使加热炉所有支路的温度达到一致的同时,确保调节过程中总进料流量不变。由于仅利用了相邻支路的温度信息,使得所提分布式偏差控制方案在大规模支路情形下更显优势。最后仿真实例表明了该分布式控制方案的有效性与可行性。     

基于PCS7的加热炉控制方案设计及实施

针对工业生产中常见的加热炉装置,设计了基于西门子公司PCS7过程控制系统的控制方案。为了保证物料出口温度、烟气含氧量和物料流量达到需要,采用了比值-串级控制系统、前馈控制系统和史密斯滞后补偿器。同时为了达到节能的目的,引入变频调速技术调节物料和燃料的流量。控制过程采用高级多功能过程实训系统仿真加热妒,利用PCS7控制系统实施控制方案并利用上位机软件进行在线的实时监控。     

前馈控制策略在德士古水煤浆气化炉进氧流量压力控制中的应用

介绍了一种使用前馈控制策略提高多台并列运行德士古水煤浆气化炉入口氧气总管流量压力控制稳定性的方法,该方法将水煤浆气化炉事故停炉过程中的支管氧气流量变化量、氧气总管放空阀的流量特性和开关速度及支管氧气切断阀关断时间综合起来生成前馈控制信号,将此前馈控制信号加到氧气总管放空回路中,及时放掉事故停炉过程中多余的氧气,以达到稳定剩余运行气化炉支管入口氧气流量压力的目的。实际使用证明,此方法控制效果良好,提高了德士古气化炉的运行安全性。     

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。