超细煤粉NOx和SO2排放特性与燃烧特性

将合山煤分别制成常规粒度的煤粉与超细化煤粉 .在单只水平直流燃烧器燃烧室内进行了常规煤粉与超细化煤粉的燃烧特性、空气分级燃烧NOx 排放特性、炉内喷钙对超细化煤粉与常规煤粉燃烧SO2 排放特性的影响的燃烧试验研究 .试验研究表明 ,超细化煤粉与常规煤粉比较 ,着火提前 ,着火稳定性好 ,燃尽效果好 ;分级燃烧对超细煤粉的NOx 排放量的降低效果更显著 ;在Ca/S摩尔比相同的条件下 ,超细化煤粉的固硫特性明显优于常规煤粉 .     

超细煤粉NOχ和SO2排放特性与燃烧特性

将合山煤分别制成常规粒度的煤粉与超细化煤粉．在单只水平直流燃烧器燃烧室内进行了常规煤粉与超细化煤粉的燃烧特性、空气分级燃烧NOχ排放特性、炉内喷钙对超细化煤粉与常规煤粉燃烧SO2排放特性的影响的燃烧试验研究．试验研究表明，超细化煤粉与常规煤粉比较，着火提前，着火稳定性好，燃尽效果好；分级燃烧对超细煤粉的NOχ排放量的降低效果更显著；在Ca／S摩尔比相同的条件下，超细化煤粉的固硫特性明显优于常规煤粉．     

Fe2O3和K2CO3对高灰分煤催化燃烧影响及机理分析

为提高淮北矿区高灰分煤的燃烧效率,采用热重分析实验对比分析了Fe2O3和K2CO3对煤粉着火与燃尽温度、燃烧特性指数、放热面积的影响.结果发现Fe2O3和K2CO3可分别将煤粉的着火温度由480.3℃降低470.4℃和397.3℃,燃尽温度由628.4℃降到609.7℃和547.7℃,燃烧特性指数提高,放热量增大.利用SEM、XRD和FTIR测试技术对煤粉燃烧残余物的微观结构、物相组成及官能团变化进行研究,分析燃煤催化剂在燃烧反应中的作用机理;通过BET方程计算燃烧煤焦的比表面积,分析其孔隙结构的变化.结果表明Fe2O3和K2CO3的主要作用机理是促进燃烧反应过程中挥发分的析出,增强煤粉的吸附性能,加快燃烧反应过程中固定碳的燃烧.     

H2O(g)对富氧燃烧超细颗粒物生成特性影响

为实现富氧燃烧技术的广泛推广,对煤粉燃烧在富氧气氛下的颗粒物排放特性进行了研究。在1800 K管式炉内进行煤焦燃烧试验,研究了富氧气氛下H₂O(g)体积分数(0、5%、10%、20%、30%)对煤焦燃烧超细颗粒物的影响;采用荷电低压撞击器(ELPI+)获得超细颗粒物质量和数量浓度粒径分布并进行分析。结果表明,H₂O(g)对超细颗粒物质量浓度和数量浓度粒径分布无影响,但会导致超细颗粒物的峰值波动。超细颗粒物总数量由最小粒径超细颗粒物决定,5种水蒸气浓度下EL?PI+第1级撞击器收集到的超细颗粒物数量占比均超过65%。超细颗粒物总质量由最大粒径超细颗粒物决定,5个水蒸气浓度下ELPI+第7级撞击器收集到的超细颗粒物质量占比均超过94%。低H₂O(g)浓度会抑制超细颗粒物生成,H₂O(g)体积分数为5%时的抑制作用最显著;高H₂O(g)浓度会促进超细颗粒物生成。这是因为一方面H₂O(g)与煤焦发生气化反应,使煤焦颗粒周围产生还原性气氛,促进矿物质还原为单质,进一步促进矿物质蒸发;另一方面气化反应是吸热反应,会降低煤焦颗粒燃烧温度,同时H₂O(g)加入也导致烟气热容增加进一步降低,煤焦燃烧温度抑制煤中矿物质的蒸发,导致超细颗粒物生成减少,是2种作用相互竞争的结果。此外,H₂O(g)的加入使超细颗粒物平均粒径增大,0~5%H₂O(g)时超细颗粒物平均粒径增大最迅速。     

循环流化床中谷壳与煤共燃SO2生成特性研究

在循环流化床实验台上,对谷壳与煤共燃的SO2生成特性进行了实验研究,着重研究了床温、过量空气系数对SO2生成特性的影响.实验表明,谷壳与煤共燃能够使煤燃烧的SO2生成量降低50%以上;加入谷壳的比例存在一个最佳范围,不超过30%;共燃时SO2的生成量随床温的升高而增加,SO2的减排率随床温的升高呈起伏变化,温度为850℃时减排率最大;共燃时过量空气系数变化对SO2的生成量无显著影响.     

小龙潭褐煤燃烧细粒子生成演化的实验研究

为了解煤燃烧过程中细粒子的分布特征和形成机理 ,进行了小龙潭褐煤的滴管炉燃烧实验 .收集的细粒子尺寸分布和形貌已经在不同的操作参数下进行了测量 ,由此得到细粒子的分布特征并探讨燃烧过程中温度对细粒子生成的影响 ,同时利用 SEM分析细粒子生成演化的过程 .煤粉燃烧细粒子的粒径分布呈典型的双峰分布 .不同燃烧温度下 ,细粒子尺寸的变化说明细粒子的形成机理是气化—成核—凝聚机理 ,并且测得的细粒子生成演化的 SEM图样与细粒子生成机理相吻合 .     

深度空气分级下煤粉耦合氨燃烧及NO生成特性

氨作为一种富氢的无碳燃料,具有能量密度高、成本低、储运安全等优势,与煤粉耦合燃烧可降低煤燃烧过程中CO₂的排放。以某20 k W沉降炉(氨从煤粉火焰高温区喷入)为研究对象,在深度空气分级下对煤粉耦合氨燃烧特性及NO生成规律进行研究,通过Fluent数值模拟探究了氨掺混比例(0、10%、20%、30%)、氨燃烧区过量空气系数(1.08、0.96、0.84、0.72)、氨不同送入位置(0.5、0.6、0.7、1.0 m)对煤粉燃尽特性及NO生成特性的影响。结果表明:(1)与纯煤粉燃烧相比,煤粉中掺混氨后飞灰含碳量增加、NO生成量降低;氨掺混比例进一步提高会增加飞灰含碳量、降低NO生成量。考虑燃烧经济性和NO排放量,氨掺混比例维持在20%左右较为合适。(2)氨燃烧区过量空气系数大于1时,氧量过剩会导致反应NH₃+O₂→■NO+H₂O+0.5H₂发生,生成大量NO;氨燃烧区过量空气系数小于1时,未完全燃烧的氨发挥还原作用,有利于反应NH₃+NO■→N_2<...     

流化床富氧气氛对SO2排放特性的影响

为了研究富氧燃烧气氛下煤在流化床中燃烧SO2排放特性,利用小型流化床反应器,以褐煤和无烟煤为试验原料,分别在21%、29%、42%和56%O2/CO2气氛下进行了燃烧试验,探究了燃烧气氛对流化床煤燃烧中SO2排放的影响。结果表明,在O2/CO2气氛下,随着氧气浓度的提高,2种不同类型的煤在770℃燃烧后,SO2排放量逐渐升高,褐煤SO2排放量从925×10-6增加到6 526×10-6,无烟煤的SO2排放量从1 310×10-6增加到5 357×10-6。与无烟煤相比,褐煤升高趋势更为明显。氧气浓度对SO2析出速率的影响显著,在15 s甚至更短时间使得SO2析出达到更高的峰值。氧气浓度从21%增至29%时,转化S显著增加,之后随着氧浓度增加,转化S增长趋缓。从机理上解释,高氧浓度为硫化物析出提供了更充足的氧气,促进了SO2的生成,同时高氧浓度加速了挥发分和焦炭的燃烧速度,改善了煤的燃烧和燃尽特性。通过增强煤本身的自热效应,煤燃烧过程加快,促进煤中硫元素的释放,SO2排放量也相应增加。随着氧浓度的增加,褐煤的CO保持在相对稳定的水平,说明氧浓度的变化对此影响较小。褐煤挥发分高,容易出现停留时间不足,导致不充分燃烧,烟气中含有一定量CO等气体。SO2的排放除了与氧气浓度有关外,主要还与煤中含硫量有关,通常含硫量越高,煤燃烧产生的SO2越多。由于试验煤种含硫量均较高,因此SO2排放量处于较高水平,在富氧燃烧过程中,针对含硫量较高的煤种,应充分考虑SO2排放控制问题。灰分也会影响SO2排放量,SiO2和Al2O3对SO2转化为SO3的影响较小,而CaO和MgO作用明显,煤灰中Fe2O3、K2O等含量对此转化过程也有一定影响。     

超细煤粉快速热解动力学特性实验研究

采用居里点裂解器及气相色谱仪研究了3种超细煤粉的快速热解特性。实验发现:超细煤粉挥发分的快速热解释放主要发生在升温阶段,烟煤与无烟煤挥发分中焦油的质量分数均最大,其中烟煤焦油释放量占挥发分的质量分数达到50%以上,高于无烟煤。烟煤气态挥发分中CO质量分数最大,达到40%以上,其次为CO2,然后依次为CH4、其他碳氢化合物CnHm,H2。无烟煤的CO,CO2,CH4释放质量分数基本相当,H2质量分数与CnHm接近。根据热解产物的释放数据,采用单方程反应模型计算出了煤粉升温速率、热解频率因子及活化能,为进一步研究超细煤粉的着火及燃烧提供了理论基础。     

煤粉添加高炉除尘灰混合燃烧特性及动力学研究

利用热重分析天平,采用非等温燃烧方法对除尘灰与2种煤粉的混合试样的燃烧特性及其反应动力学参数进行了实验研究. 考察了不同配比的混合试样的着火温度、燃烧速率最大时温度、燃尽温度和最大燃烧速率等燃烧特征参数,计算了反应的动力学参数活化能Ea和指前因子A. 结果表明,两参数均随混煤中除尘灰比例的增加而降低,存在"动力学补偿效应". 煤中掺入除尘灰后,试样燃烧的第一和第二阶段的Ea均呈现下降规律,但对不同煤粉影响效果程度有较大差别. Ea的计算表明,除尘灰的存在有助于改善煤的着火性能,对煤的燃烧有催化促进作用,且5%为最佳掺混比例.     

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。