水泥厂余热发电励磁系统的几种运行方式

本文概述了水泥厂余热发电项目励磁系统的几种运行模式,以适用于水泥厂余热发电的并网运行。以梅州市梅盛伟业水泥有限公司的余热发电的励磁系统为例,并通过现场的试验报告来验证励磁系统的运行效果。     

余热发电励磁系统常见故障分析

余热发电机组容量较小,一般采用并激式直流发电机作为同轴直流励磁机。励磁系统能否正常运行,对同步发电机可靠的发供电起着重要作用。因此,针对余热发电的一些特殊性,我们对励磁系统常见的一些故障加以分析,以供参考。1 励磁系统接地     

微机励磁装置在硫酸装置余热发电中的应用

分析了BLK-5同步发电机微机励磁装置在120 kt/a硫铁矿制酸余热发电3 000 kW发电机组励磁系统的相应配置和使用情况,实践证明:该微机励磁装置功能齐全,结构简单,维护方便,性能优越,使用后不仅提高了系统控制精度、可靠性和稳定性,而且有效解决了余热发电装置运行可靠性差、励磁系统故障率高等一系列的问题,大大降低了余热发电机组的故障率,减少了维修工时和员工的劳动强度,增加了一定的社会效益和经济效益。     

余热发电励磁系统常见故障分析

干法中空窑的余热发电机组容量较小,一般均采用并激式直流发电机作为同轴直流励磁机。励磁系统能否正常运行,对同步发电机可靠的发供电起着重要作用。因此,针对余热发电的一些特殊性,我们对励磁系统常见的一些故障加以分析,以供参考。     

7000kW小型自备发电机组励磁系统初探

介绍了我厂7000kW小型自备发电机组励磁系统,并对励磁柜内励磁调节器、移相触发单元、过励限制单元、低励限制单元做进一步阐述。     

微机励磁系统在硫酸装置余热发电中的应用

励磁调节是发电装置的重要控制设备,随着微电子技术和计算机技术的飞速发展,微机励磁控制在硫酸装置余热发电中得到了应用.介绍其主要功能、特点和在300 kt/a硫磺制酸装置余热发电系统中的配置情况,运行证实该技术投资少、功能全、结构简单、维护方便、运行可靠性高、动态性能指标优良,值得推广.     

余热发电并网后对原供电系统的影响

<正>我公司在2007年对2005年投产的某条5 000t/d生产线增加了装机容量为9MW的纯低温余热发电系统,由于发电机组是一个新的电源供给点,它的并网接入必然会对原有系统的短路能力、功率因数和保护参数等造成一定的影响。1电气接入系统方案余热发电系统接入单线图见图1。9MW发电机型号为QF1-W9-2,无刷励磁。余热电站侧6.3k V母线经单回电缆线路与总降的6.3k V母线连接,实现并网运行,运行方式为并网电量不上网。该系统在电站侧的发电机联络开关和发电机出口     

大型硫磺制酸装置余热发电电气技术与实践

硫磺制改装置余热发电是否作为企业的一个独立电源是普遍关心的问题。介绍了余热发电系统的主接线、发电配电并网、发电机励磁调节和各种保护措施，指出余热发电是按热电结合、以热定电而设计的，虽不能作为一个独立电源，但可缓解电力供需矛盾，且在外电网计划停电时，发电机组可与外电网解列，单独运行，实行硫磺制酸系统发电自保。     

某硫铁矿制酸装置余热发电机励磁控制系统的改造

针对某硫铁矿制酸余热发电装置原有励磁设备存在的系统稳定性和抗干扰能力差、故障率高、维修困难等情况,对发电励磁控制系统进行了改造.介绍了GER3000微机励磁调节装置的优点,分析了其用于该项目改造的可行性,阐述了该改造方案及改造过程.改造后新的励磁控制系统安全可靠,运行稳定,操作维护简单便捷,保障了发电机组安全稳定运行.     

发电机欠励运行的危害

由于励磁回路的部件及自动励磁调节装置发生故障或由于系统事故造成发电机欠励运行,严重时将破坏电力系统的稳定运行,威胁发电机的自身安全。为限制发电机的进相无功不超过允许范围需装设欠励限制器以限制励磁电流的减少。     

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。