提高注汽锅炉热效率浅析

热效率就是锅炉输出的热量占燃料燃烧放出的热量的百分数。影响锅炉热效率的主要因素是排烟热损失、气体不完全燃烧热损失、炉体散热损失。其中排烟热损失是影响热效率的重要因素。通过对各项因素的分析,找出提高锅炉热效率的途径:降低排烟温度和过剩空气系数以降低排烟热焓;选用高效保温材料,提高辅射段、对流段、过渡段保温效果,降低炉体散热损失;调整合理的过剩空气系数,保证锅炉良好燃烧,降低气体不完全燃烧损失。     

排烟热损失对燃煤工业锅炉热效率的影响

为了研究排烟热损失对燃煤工业锅炉热效率的影响程度和变化规律,通过分析近年来1205台燃煤工业锅炉测试数据,得到了当其他参数达到GB/T 15317—2009《燃煤工业锅炉节能监测》规定合格指标且排烟温度在100~200℃时,锅炉热效率-排烟热损失、排烟热损失-排烟温度、排烟热损失占锅炉热损失的比例-排烟温度和锅炉热效率-排烟温度的变化规律曲线及相对应的一元线性回归方程。结果表明:排烟热损失每增加1.0%,锅炉热效率降低1.12%;锅炉排烟温度每增加10℃,排烟热损失增加0.5%,排烟热损失占锅炉热损失的比例增加1.5%,锅炉热效率降低0.6%。     

给水预热器及膜式水冷壁对注汽锅炉热效率的影响

提出多种注汽锅炉改进方案,包括去除给水预热器、辐射段采用膜式水冷壁和在只具有烟气转向作用的过渡段增设膜式水冷壁。通过热力计算综合对比不同改进方案对注汽锅炉热效率、排烟温度、换热温压及燃料消耗量等重要参数的影响,并确定最佳改进方案。结果表明:去除给水预热器可以大幅提高油田注汽锅炉热效率。辐射段与过渡段采用膜式水冷壁对排烟温度影响较小,但可以有效降低对流段入口烟温,降低对流段管子超温烧毁的几率。     

远红外节能剂在油田注汽系统的应用

我国稠油主要采用蒸汽吞吐和蒸汽驱的热采方式,稠油热采所用的注汽锅炉消耗了大量的燃料,平均燃油单耗为63kg/t,热采锅炉已成为稠油油田最大的耗能设备。为降低热注锅妒燃油量,提高锅炉热效率,对热注锅炉节能涂料进行了攻关研究,经过室内研究与现场试验,锅炉表面平均温度降低12.85℃,平均热效率提高3.35%,节能效果显著。     

金马油田提高注汽锅炉热效率研究与应用

注汽锅炉是稠油热采的主要设备，稠油热采注汽系统成本占稠油开采总成本的60%以上，由此可见确保注汽锅炉高效经济运行，是降低稠油开发成本，提高经济效益的关键。在深入开展注汽锅炉热效率理论分析的基础上，加强技术创新和技术革新，强化产汽、输汽、注汽环节过程管理，从而实现了热效率的稳步提升，为热注系统优质低耗注汽提供了有力支撑。     

注汽锅炉烟气余热回收

注汽锅炉是油田热采的主要动力设备、耗能设备之一。由于注汽锅炉在油田分布比较分散,从而烟气余热大多随烟气排入大气,能量被白白的浪费掉了,这就使得注汽锅炉的热效率不高。利用螺杆膨胀机回收烟气余热,通过螺杆膨胀机输出动力来代替给原注汽锅炉给水泵等动力设备提供动力的电能,从而提高了注汽锅炉的热效率,达到节能减排的目的,有利于社会的可持续发展。     

提高油田注汽锅炉系统热效率技术研究

我国有丰富的稠油资源,稠油油田开发过程中,注汽锅炉系统能耗占总能耗的绝大部分,因此提高注汽锅炉系统热效率是节能降耗、降本增效的重要研究方向。本文主要论述了提高油田注汽锅炉燃烧控制系统热效率的新技术,以有效促进节能降耗,提升经济效益。     

火电厂如何提高锅炉热效率

排烟热损失,化学不完全燃烧热损失,机械不完全燃烧热损失,散热损失,灰渣物理热损失是锅炉的主要热损失。其中排烟热损失,机械不完全燃烧热损失在锅炉各项热损失中所占比例较大,本文通过对燃煤锅炉风量的调整、煤粉细度的控制等方面来降低排烟热损失、机械不完全燃烧热损失,从而提高锅炉效率。     

浅析稠油热采注汽锅炉的维护与保养

稠油油藏进行开发时,根据稠油油藏地下原油的物性特点,蒸汽吞吐热采是各大稠油油田普遍采用的一种有效的开采方式。对于注汽开采的油田,注汽锅炉是一个最常见也是最重要的设备之一,其在油田开采过程中的重要性不言而喻,注汽锅炉的能否安全稳定的运转直接影响到整个油田的正常生产和开发,为了使注汽锅炉能够保持持久的平稳运行,做为设备管理人员,我们必须从日常的使用入手,从基础的管理细节出发,加强对注汽锅炉设备的日常维护和保养,延长设备的使用寿命,降低设备的故障率,减少热效率的损失,提高工作效率,降低生产成本,为油田的提供充足、优质的蒸汽。     

如何降低注汽锅炉排烟热损失

注汽锅炉的热损失包括排烟热损失、机械不完全燃烧热损失、化学不完全燃烧热损失、散热损失和灰渣物理热损失,其中,排烟损失是最大的一项,一般占到燃料总热值的7⁸%,第二是机械不完全燃烧损失占到18%,第二是机械不完全燃烧损失占到1²%,而化学不完全燃烧损失、散热损失、灰渣物理热损失只占很少份额。所以在研究锅炉经济性时应重点控制排烟损失,而影响排烟损失的主要因素是排烟容积(用排烟氧量来标志大小)和排烟温度,这三个指标是研究锅炉效率最应注意的。     

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。