异丁烷脱氢过程催化剂结焦与焦性质研究

在固定床反应装置上,采用YBD型Cr/Al_2O_3催化剂催化异丁烷脱氢,通过热分析技术研究结焦催化剂,考察反应条件对催化剂结焦量及焦性质的影响。结果表明,Cr/Al_2O_3催化剂对异丁烷脱氢有较好的催化活性,当反应温度580℃,空速800 h^(-1)时,异丁烷转化率60%以上,异丁烯选择性90%以上,异丁烯收率约60%。反应温度、空速以及异丁烯对结焦催化剂的焦含量有明显影响,当反应温度超过580℃,随着原料气中异丁烯含量的增加,催化剂的结焦量迅速增加。     

原料油汽化特性对催化裂化反应结焦过程影响的CFD模拟

为考察原料油汽化特性影响,在一套百万吨级工业FCC提升管中,基于多相欧拉模型耦合EMMS曳力和传质、油滴汽化和十二集总反应动力学模型,采用三维CFD模拟研究气液固三相流动、汽化、反应、结焦的复杂过程,新开发结焦预测模型定量预测结焦状况,对比研究不同原料油雾化液滴粒径和起始汽化温度下各相和反应组分浓度场、温度场分布和结焦程度。结果表明,模拟方法可较准确预测汽化、反应生焦和结焦过程,不同雾化液滴粒径和起始汽化温度通过流场分布和汽化快慢影响液相油滴汽化率和反应转化率;合适液滴粒径(60 μm)和起始汽化温度(654 K)可提升轻油、汽油、液化石油气目标产品收率并改善结焦程度。     

原料油汽化特性对催化裂化反应结焦过程影响的CFD模拟

为考察原料油汽化特性影响,在一套百万吨级工业FCC提升管中,基于多相欧拉模型耦合EMMS曳力和传质、油滴汽化和十二集总反应动力学模型,采用三维CFD模拟研究气液固三相流动、汽化、反应、结焦的复杂过程,新开发结焦预测模型定量预测结焦状况,对比研究不同原料油雾化液滴粒径和起始汽化温度下各相和反应组分浓度场、温度场分布和结焦程度。结果表明,模拟方法可较准确预测汽化、反应生焦和结焦过程,不同雾化液滴粒径和起始汽化温度通过流场分布和汽化快慢影响液相油滴汽化率和反应转化率;合适液滴粒径(60 μm)和起始汽化温度(654 K)可提升轻油、汽油、液化石油气目标产品收率并改善结焦程度。     

在 AF-5分子筛催化剂上乙烯对苯的气相烷基化反应结焦规律的研究

本研究采用玻璃结构的磁驱动内循环无梯度反应器,考察了反应温度为340℃～420℃,苯/乙烯为5～1的分子比范围内,AF—5分子筛催化剂在乙烯对苯的气相烷基化反应中的结焦规律。在试验范围内,得到了结焦速率式,结焦量与反应时间,结焦量与催化剂活性的关联式。研究结果表明,结焦反应可用平行连串反应历程来表示:苯→乙苯→二乙苯焦母体焦测定了反应温度、反应时间、乙烯分压,空速和催化剂颗粒度等参数对结焦的影响。本研究还推测了 AF—5分子筛催化剂的失活机理;0t_b,单分子焦层的活性位覆盖和多分子焦层引起孔道狭窄的联合效应。     

低碳烃芳构化催化剂烧炭再生动力学

以结焦的ZSM-5分子筛催化剂为研究对象,在热重分析仪上进行催化剂再生烧炭实验,在500~650℃和氧分压10~25 k Pa的条件下,考察了再生温度、氧分压及时间对烧炭过程的影响,计算得到含碳量1.3%(质量分数)的催化剂的再生动力学参数,回归得到ZSM-5分子筛催化剂再生动力学模型。结果表明,适宜的再生烧炭温度在600℃左右,适宜的氧分压为15~20 k Pa。ZSM-5结焦催化剂的烧炭反应速率与炭含量和氧分压的关系符合一级反应规律,该模型能较好地拟合实验数据。     

桃金娘烯醛催化异构成紫苏醛的动力学研究

研究和探讨了桃金娘烯醛催化 -异构成紫苏醛的反应动力学及其模型。对影响动力学的主要因素 :压力 ,温度进行了讨论 ,得出催化异构的最佳反应条件 :温度 450°C,真空度 1 0～ 1 1 .6k Pa,且得出了此气固反应的动力学模型 ,并对模型进行了理论验证。     

催化轻柴油芳烃热脱烷基制萘

本试验是以催化裂化轻柴油芳烃为原料油、工业氢为原料气,热法脱烷基制萘。试验主要围绕测定结焦位置和减少结焦倾向,同时做了一些温度、压力、气油比和停留时间对脱烷基反应深度的影响。尚未做寿命试验。通过这一阶段工作,可以看出:     

乙烯三聚制己烯-1催化剂的反应行为和动力学

采用微机采集数据的搅拌釜反应器对实验室自制的催化剂进行了反应行为和动力学研究。讨论了催化剂加入量、反应温度和压力对催化剂活性的影响。当催化剂加入量在 0 .5～ 2ml时 ,最大反应速率与催化剂加入量呈一级动力学关系 ;反应压力为 4.0～ 6 .0MPa时 ,最大反应速率与乙烯压力呈三级动力学关系 ,并据此求出反应温度为 95～ 130℃时催化剂上乙烯三聚反应的表观活化能     

Shell粉煤气化制氨工艺中变换反应的分段研究

采用动力学方程式,针对某厂Shell粉煤加压气化工艺条件,设计了动力学模型,对变换反应的分段问题,特别是第一段反应器反应深度的控制问题进行了研究和讨论;考察了水／气、反应压力和床层热点温度对甲烷化副反应的影响。     

添加结焦抑制剂的轻柴油裂解反应和结焦反应模型

本文研究了有结焦抑制剂YZS1存在时的轻柴油裂解和结焦反应动力学.考虑了结焦抑制剂的功能,组合了裂解反应新的反应图式,提出了添加结焦抑制剂YZS1的轻柴油裂解反应动力学模型.实验证明裂解反应的结焦前兆体是乙烯、丙烯和芳烃,进而提出了简化的结焦动力学模型.     

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。