三通道喷煤管的改进

我公司中3.75×57m回转窑的燃烧器采用三通道喷煤管。由于原结构设计的缺陷,该三通道喷煤管投运后煤粉入口处的内风管磨损严重,通常运转两个月就被磨穿,致使煤粉窜至内风道,不仅使火焰失去控制,且将喷嘴烧坏,窑运转率下降。为此,我们在实践的基础上,对煤粉风管和内风管作了改进,基本解决了因煤粉冲刷对内风管严重磨损的问题。 原喷煤管煤粉入口段的结构如图1。     

TJB型四风道喷煤管在我厂立筒预热器窑上的应用

0 前言 我厂φ3 m/2.5 m×40m“三旋一立”立筒预热器窑系由φ2.5 m×40 m径阳型立筒预热器窑改造而成的,年产高标号水泥20万t。该窑的煤粉燃烧一直使用传统的单风道喷煤管,由于这种喷煤管的风、煤混合较差,又不能调节,造成窑系统热耗高、产量低,熟料质量差,工艺事故多。 为解决这一问题,我们通过广泛调查研究,决定用天津博纳建材高科技研究所生产的TJB四风道喷煤管取代原单风道喷煤管。本次改造于2000年8月完成并点火投料,2a来的运行实践表明,该燃烧器对煤种的适应性强,点火容易且升温快,火焰调节灵活,操作简单可靠。本文拟介绍我厂立筒预热器窑喷煤管改造情况及其效果。     

回转窑煤燃烧器的理论及实践（上）

介绍了煤粉燃烧器前端的热化学反应与传热,给出了单风道煤粉燃烧器的计算公式及喷头几何尺寸参数,简略简明了双风道及多风道煤粉燃烧器的工作原理,以利我国煤粉燃烧器的研制、应用与推广。     

回转窑煤粉燃烧器的发展趋势、特点及选择(一)

当前回转窑煤粉燃烧器的发展趋势是:由三风道向四风道发展;由分割式向旋流式发展;由烧优质烟煤向烧低质煤和废燃料发展;在大中型生产线上,由引进向国产发展.四风道煤粉燃烧器的特点:一次风用量小,节能显著;风速高,推力大;调节灵活,火焰形状可以多变;火焰形状好,没有峰值温度;外风从间断出口喷出,永不变形.四风道煤粉燃烧器为低质煤的运用提供了技术支持.一些四风道煤粉燃烧器头部件易烧损磨蚀,下煤处易磨漏磨穿,中间容易弯曲,浇注料寿命短,企业在选用时必须重视,对国内外燃烧器要正确评认,应认真落实性价比.在燃烧器的采购中应搞清楚有关煤粉燃烧器名词术语的基本概念,还要了解国内外煤粉燃烧器市场状况,做到准确地采购.     

多风道煤粉燃烧器的适用性

多风道煤粉燃烧器不仅适用于新型干法窑,也适用于其它任何回转窑窑型,并且都会取得明显的经济效益。采用四风道煤粉燃烧器来改造现有十分落后的单风道、已显逊色的双风道和三风道煤粉燃烧器符合当前国内外的发展趋势,是花钱少,见效快,又不需停产的一项有力的技术措施。     

单风道喷煤管法兰盘联接的改造

我厂现有２台回转窑，燃烧装置一直采用单风道喷煤管。使用中经常出现喷煤嘴与喷煤管法兰盘联接处有煤粉呲出的现象。并随着使用时间的延长，煤粉呲出现象逐渐加重并有时燃烧，缩短了喷煤嘴的使用寿命，造成火焰形状不规则、看火操作困难、视物不清，影响窑的煅烧。其原因为喷煤嘴与喷煤管联接法兰盘使用一段时间后，受热变形。现将法兰盘联接形式由简单的密封改为迷宫式密封后（见图１），收到了理想的效果。原喷煤嘴２～３个月必须更换１次，改造后延长至５～６个月更换１次，呲煤粉现象再没有发生过。图１喷煤管法兰盘联接改造前后示意值…     

确定燃烧器在窑口端面位置的一种方法

随着技术水平的不断发展和创新,用于回转窑的煤粉燃烧器(习惯称喷煤管)亦越来越先进和完善。各种类型的三通道、四通道喷煤管已普遍应用到了各类新型干法窑系统。 实践证明,喷煤管的使用效果,除了其自身要     

双风道煤粉燃烧器的结构性能分析

为了有空间插入多种燃料输送管以满足燃烧多种燃料的需求，某煤粉燃烧器取消了中心风，采用了双风道结构；并且为了使高温二次风尽快地与煤风中的煤粉接触，将煤风道置于最外层；为了在操作时根据需要随时能够调节旋流度，该燃烧器净风采用万向可调的多个小喷嘴喷射，随时可以调节火焰形状，以满足窑工况变化或者熟料烧成的需要。实践证明，这种燃烧器一次风用量并非最小，性价比不高，但设计理念值得借鉴。     

TJB四风道煤粉燃烧器在NSP窑上的使用

换用燃烧器前,煤粉不能完全燃烧,窑内长厚窑皮、结后圈频繁、烟室缩口结皮甚至堵塞,窑产提不上去。改用TJB-KP-7型煤粉燃烧器后,使用更低低位热值的煤粉,烧成系统以上现象大大减少。实践证明,该燃烧器火焰调节方便灵活,各个风道的喷出速度调节可控,一次风用量低,燃烧器的推力大。     

国产四风道煤粉燃烧器及应用效果

０引言回转窑煤粉燃烧器已由单风道发展到三风道、四风道和烧两种或三种燃料的五风道。风道越多,性能越好,可是结构就越复杂。性能优良的四风道煤粉燃烧器一次风用量一般已可降到５％－７％,甚至３％－４％,既可以烧优质烟煤,也可以烧劣质煤、低挥发分煤、无烟煤、石油焦、煤页岩、废轮胎和生活垃圾等。但国内目前还不能供应四风道的燃烧器,现用厂家都是从国外进口,价格昂贵。为填补这项空白,尽快赶上世界先进水平,天津市博纳建材高科技研究所开发研制了ＴＪＢ型旋流式四风道煤粉燃烧器。１国产四风遭煤粉燃烧器的结构特点在国外旋…     

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。