栲胶脱硫工艺操作条件的优化

采用正交实验法,分别将2 h和4 h的脱硫效率及碱耗作为评价指标,考察了碱度、栲胶浓度、偏钒酸钠浓度及温度的影响。结果表明,对脱硫效率的影响程度为碱度>温度>栲胶浓度=钒浓度,对碱耗的影响却是随时间变化的;栲胶浓度和钒的浓度对脱硫效率及碱耗的变化趋势相同;胶钒比宜控制在1.5~1.7,温度在25~30℃。     

栲胶脱硫液电位及其应用讨论

栲胶法脱硫是广西化工研究所等近年开发的湿式氧化脱硫工艺,已有若干小氮肥厂和中型氮肥厂相继使用。为了从氧化还原电位理论了解碱性氧化栲胶溶液的氧化能力,以便估价溶液的适宜操作组份以及有助于降低腐蚀的探索,使栲胶法趋向完善。本实验依据生产实际溶液之碱度和含量,在Na_2CO_3～NaHCO_3介质(Na_2CO_3和NaHCO_3折以Na_2CO_3计算的两者总量为25.0克/升)、溶液pH=8.5～10.0、原料栲胶含量1～5克/升条件下,测定了25℃时溶液的电极电位。得出pH～毫伏呈线性反比关系;原料栲胶含量浓度的对数与溶液电极电位亦呈线性关系。此外,还考察了五价钒、四价钒离子对碱性氧化栲胶溶液电极电位的影响,得出溶液对四价钒有相当可观的氧化能力,並且从电位和光谱实验数据推测出五价钒与氧化栲胶不形成络合物。继之,根据上述实验结果,对栲胶法脱硫的操作,从理论上提出一些看法。     

栲胶法回收黑药生产中释放的高浓度硫化氢试验

在自行组装的脱硫再生实验装置上，采用模拟的工业气体研究了栲胶溶液处理黑药生产中释放的高浓度硫化氢气体以回收硫磺的工艺条件。结果表明，适宜的工艺条件为：栲胶溶液pH11．0～11．5，栲胶浓度为1．2g／L，偏钒酸钠浓度为0．9g／L，吸收温度35～40℃。在适当的条件下.用栲胶溶液处理高浓度硫化氢气体，脱硫率高，可生产纯度〉99．32％的硫磺。     

栲胶-偏钒酸钠高硫容脱硫小试验

四川天然气研究所在广西研究所等开发的栲胶-偏钒酸钠法脱硫的基础上,使用成都橡碗栲胶-偏钒酸钠溶液提高硫容脱除天然气中低硫的试验。通过静态及动态试验确定了溶液组成、考查了工艺条件的影响;并在500小时连续试验运转中考查了溶液的化学性能、工艺性能及物料的化学消耗指标。静态试验试验条件:原料天然气41标升/时,H_2S(原)7～8克/标米~3,CO_2(原)10％,空气75标升/时,温度40℃,脱硫液300毫升。静态试验以栲胶/NaVO_3重量比(简称胶钒比)、NaVo_3浓度及总碱度为因子安排了     

准确、快速测定栲胶脱硫液中总碱和悬浮硫含量的新方法

以煤焦为原料的合成氨生产装置中，大多数厂家已经由原来的加压A．D.A脱硫改为效率较高、经济性较好的栲胶脱硫。栲胶脱硫液中主要含有栲胶、碳酸氢钠、碳酸钠、钒酸钾、悬浮硫、硫氢化钠、硫代硫酸钠等，栲胶脱硫的反应机理是利用碱性溶液吸收半水煤气中的H2S，然后借助栲胶和钒做为载体和膣化剂将吸收的H2S转化为单质硫。其中总碱的含量高低是栲胶脱硫液实现高效脱硫的重要指标，而悬浮硫的含量则影响栲胶溶液的脱硫能力，它将为溢硫操作提供依据。     

栲胶在加压变换气中脱硫的应用

1　变脱系统的运行情况1 .1　溶液的配制溶液在配制时 ,应该把握好 :①必须使用熟化质量好的栲胶 ,否则会出现发泡和腐蚀现象 ;②保证碱与钒的量比 >4∶1。在溶液中能起到将单质硫氧化出的物质是钒 ,所以应该保证溶液中钒的含量 ;③保持变脱溶液系统的总碱度 0 .45mol/L ;④变脱溶液 pH值应控制在 8.5左右。1 .2　系统运行系统运行时应该把握好 :①控制溶液温度在45℃左右 ,栲胶使用的最佳环境在 43～ 48℃ ;②减少塔釜出废液直接回系统的回收量 ;③保证再生空气与溶液的比为 1 .2～ 1 .5。在使用过程中发现 ,栲胶在脱除硫化氢的过程中 ,不…     

栲胶脱硫副产物对脱硫液密度影响的研究

模拟栲胶脱硫液中副产物的积累过程,配制了含有不同浓度副产物的仿栲胶脱硫液,考察了栲胶脱硫液中副产物对脱硫液密度的影响,得出这些副产物的积累均会使栲胶脱硫液密度增大,其中副产物Na2S2O3和NaSCN是影响栲胶脱硫液密度的主要因素。讨论了脱硫液密度与溶液中主要副产物浓度之间的关系,并用Excel软件对实验数据进行了回归分析,得到很好的线性关系,为实际生产中估算栲胶脱硫液的密度提供了一定的理论依据。     

海水脱硫效率的影响因素考察

研究了海水的盐度(实用盐度31-41)、温度(13～55℃)、碱度及填料塔填料类型对海水烟气脱硫效率的影响.实验结果表明在相同装填高度及比表面接近情况下规整填料具有更高的脱硫效率;相比海水盐度而言海水的温度及碱度则对海水的体脱硫效率影响更大,尤其是在低液气比下温度的影响尤为显著.     

栲胶脱硫副产物对脱硫液粘度的影响

模拟栲胶脱硫液中副产物的积累过程,配制了含有不同浓度副产物的仿栲胶脱硫液,考察了栲胶脱硫液中Na2SO4、Na2S2O3、NaHCO3、NaSCN等副产物对脱硫液粘度的影响。结果表明,这些副产物的积累均会使栲胶脱硫液粘度增大,其中Na2S2O3和NaSCN是影响栲胶脱硫液粘度的主要因素;讨论了脱硫液粘度与主要副产物浓度之间的关系,用Excel软件进行了回归分析,得到很好的线性关系,为实际生产中估算栲胶脱硫液的粘度提供了一定的理论依据。     

栲胶脱硫工艺中含硫副产物生成的热力学分析

采用热力学方法研究了栲胶脱硫工艺中HS-与钒的反应机理和副反应的吉布斯自由能变。研究结果表明,脱硫液中五价钒主要是以HV2O3-7形式存在,四价钒主要是以V4O2-9形式存在。HS-与五价钒反应可瞬间生成多硫离子S2-x,然后S2-x转化为单质硫。在栲胶脱硫工艺的操作温度下,HS-和S2-x与氧气作用均可生成副产物,但S2-x比HS-活泼,更易发生副反应,且S2-x中x的值越小越活泼。在S2-x转化为副产物S2O2-3的过程中,温度越高,越有利于副反应的发生。对栲胶脱硫工艺而言,S2-x是生成副产物的活性中间产物,因此,栲胶脱硫液在进入再生系统前,应使S2-x尽可能多地转化为S8结构。     

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。