复合型塔板填料参数对流体力学性能影响的研究

在内径600 mm的有机玻璃塔内,以空气-水为实验物系,测定了不同参数(筛板-填料安装间距、填料结构)的填料段与孔径8 mm、开孔率14.66%的穿流筛板组成的T/P型复合塔板的流体力学性能。实验结果表明,筛板-填料安装间距为5.5 mm时测试板干板压降较间距为0 mm时减少10%以上,液泛点延后,板上泡沫层高度增加10%~15%;各喷淋密度下,350Y型测试板在填料载点之前,压降呈线性增长,板上清液层高于250Y型,不易吹干,操作稳定性更强。喷淋密度为20 m3/(m2·h),N3/2型塔板泛点F因子为2.98(m·s-1)(kg·m-3)0.5,比250Y型增大8.4%,操作弹性提高17%,泡沫层高度也有提高。喷淋密度为60 m3/(m2·h),N5/3型测试板操作下限F因子为0.51(m·s-1)(kg·m-3)0.5,低于250Y型,操作弹性提高21%。     

高气液比复合填料板的压降与持液性能研究

为实现对低压大气量废气中的污染物进行高效的分离与富集,开发了一种高气液比复合填料板,以空气-水为实验物系,对该复合填料板的压降和持液性能进行了研究。结果表明,复合填料板的干板压降Δp与气相动能因子F的关系符合幂函数关系,在相同喷淋密度(L=30.6L·m~(-2)·h~(-1))条件下,复合填料板的动持液量较BX500填料的整体高了58～130倍。在相同L条件下F从3.2增长到6.5 m·s~(-1)·kg~(1/2)·m~(-3/2),复合填料板的湿板压降增长了162%～201%;而相同F条件下L从30增长到60L·m~(-2)·h~(-1),湿板压降增长了67%～108%。与普通填料相比,复合填料板在高气液比条件下表现出了低压降和高持液量的显著优势。     

泡沫铁铬镍规整填料的性能实验研究

为了考察泡沫铁铬镍规整填料的性能,对电沉积法制备的泡沫铁铬镍规整填料进行了流体力学和传质性能实验。结果表明:泡沫铁铬镍规整填料的压降随F因子和喷淋密度的增大而增大,液泛点的Ff因子达到2 m/(s·kg~(0.5)·m~(1.5))以上,且每米填料的理论板数达到3块板以上。相比铸造法制备的泡沫铝和泡沫碳化硅规整填料,泡沫铁铬镍规整填料的压降低、持液量小、操作弹性大,其传质性能与传统规整填料M250Y和BX500相当。在实验基础上,拟合了泡沫铁铬镍规整填料的压降关联式和液泛气速关联式,为今后的工业化设计提供指导。     

一种新型催化精馏填料的流体力学性能

填料的流体力学性能数据是填料塔设计的基础,通过实验对一种新型催化精馏填料的流体力学性能进行了测量.实验首先观测了不同气速和喷淋密度下的气液流动状况,然后对压降,泛点气速和持液量等基础数据进行了系统的测量.利用实验数据回归了不同喷淋密度下压降与气相F因子的计算关系式,给出了泛点气速的计算表达式.     

生物滴滤塔净化处理硫化氢的实验研究

在常温条件下,以陶粒和悬浮改性填料WD-F10-4为填料的生物滴滤塔系统对硫化氢废气进行净化处理,考察了不同硫化氢负荷、营养液喷淋量和气体停留时间对生物滴滤塔性能的影响。实验结果表明,当进气质量浓度为400 mg/m3,硫化氢负荷为32 g/(m3·h),喷淋量为4 L/h,气体停留时间为46 s,系统的平均去除效率为97%。系统运行期间,填料未出现堵塞现象,证明悬浮改性填料可用作生物滴滤塔的填料。     

旋转填料床中2种填料压降和传质特性的对比

分别以空气-水和磷酸钠溶液吸收模拟烟气中SO2为实验体系,对装填有θ环和波纹丝网填料的逆流旋转填料床压降和传质特性进行了对比研究,结果表明:在实验操作范围内,逆流旋转填料床的湿床压降随气量、超重力因子的增大而增大,受液量的影响很小;2种填料的湿床压降相差不大,且均低于750 Pa。2种填料的Kya均随喷淋密度、空床气速和超重力因子的增加而增大,当U=6 m3/(m2·h),u=0.73 m/s,β=85及更高的操作范围时,θ环填料的Kya比波纹丝填料高25%以上,说明θ环填料的传质性能明显优于波纹丝填料;最后得到装填θ环和波纹丝填料的旋转床湿床压降和体积传质系数的经验关联式。文中的研究结果对旋转填料床的设计和选型有重要意义。     

新型垂直板规整填料流体力学及传质性能

采用氧解吸实验,在直径190 mm的有机玻璃塔内,液相喷淋密度10～38 m³·m^-2·h^-1,F因子0.2～3.2 m·s^-1·（kg·m^-3）^0.5的实验条件下测定了一种新型垂直板规整填料的流体力学及传质性能。实验结果表明：垂直板填料的操作压降及传质性能均显著优于商业波纹填料。通过与几种经改进的250型波纹填料相比发现,两者泛点F因子整体上相当;在较高液体喷淋密度下,垂直板填料传质性能及压降均高于改进250型波纹填料;在低喷淋密度下,垂直板填料可实现压降低于改进250型波纹填料,而两者传质性能相当。此外,对填料结构改进对其性能的影响进行了单因素考察。     

计算梅花扁环压降和泛点气速的新方法

随着装置大型化和节能减排要求的不断提高,有必要对QH-2型扁环填料用于气液传质过程的设计计算方法作进一步研究,为推广应用提供更为可靠的依据。文中在Φ600mm的实验塔内用水-空气体系,在很宽的喷淋密度范围内[0—200m3/(m2·h)],系统研究了QH-2型扁环填料的流体力学性能。在大量实验数据和对多种数学模型进行比较的基础上,提出了采用改进的Billet模型计算压降和基于流动参数计算液泛气速的新方法。     

共轭环翅填料的流体力学与传质性能

以正犁削金属表面翅成形技术加工出共轭环翅填料,用富氧水解吸方法测定了38 mm铝材共轭环翅填料的流体力学和传质性能,并在相同喷淋密度和气速条件下,与同尺寸光滑表面的共轭环填料进行比较。结果表示,共轭环翅填料的单位填料高度压降比普通共轭环填料平均增加15.2%,而传质单元高度则平均降低18.3%;在中等喷淋密度60 m3/(m2.h)以下,共轭环翅填料具有较好的综合性能。     

一种适用于催化反应精馏的新型填料

为适应催化反应精馏填料需要高持液量及高效率的应用特点,开发了一种新型多层丝网填料PACTU-800,并通过设计中试装置对其进行了流体力学性能测试及传质性能测试。以空气-水为测试物系的冷模实验表明,F因子为0—0.55时,喷淋密度增大则压降增大,F>0.55时,压降变化没有明显规律;并经拟合得到泛点气速公式,与贝恩-霍根公式计算值相对误差为9.1%;以正庚烷-甲基环己烷为测试物系的热模实验表明:该填料理论板数较高,且F因子对其影响不大;F>2.3时,压降开始急剧增大。结果说明:PACTU-800操作弹性大,持液量大,适合高气液负荷下操作;其通量大,压降变化小,停留时间长,效率较高且较恒定。     

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。