玄武岩催化甲烷裂解制 C2 烃

以天然玄武岩为甲烷裂解催化剂,通过XRF、XRD、SEM及XPS对催化剂组成、结构、表面活性物种进行了研究。利用固定床反应装置考察了不同反应温度、空速条件下玄武岩催化甲烷裂解制C_2烃的效果。结果表明,在气体空速为4 L·h-1条件下,当反应温度为1 225 K时,甲烷的转化率为7.66%,C_2烃的选择性为33.64%;当反应温度升至1 325 K时,甲烷的转化率可达17.13%,同时C_2烃的选择性为27.21%。相同温度下,气体空速越大,乙烷的选择性越高,乙炔的选择性越低。催化剂活性因表面积炭的产生而降低,积炭类型为芳烃积炭。     

合成气甲烷化制替代天然气热力学分析

根据热力学分析建立了等温条件和绝热条件下的合成气甲烷化的热力学模型,选取CO甲烷化反应、水汽变换反应、CO歧化反应为独立反应,CO、CH4和H2O为关键组分.基于此热力学模型可以得到等温条件下的输出气体组成、CO转化率与CH4选择性和绝热条件下的输出气体温度、组成、CO转化率与CH4选择性.并在绝热条件下讨论了输入温度...     

电弧等离子体裂解甲烷制乙炔

对C-H单相及多相热力学平衡体系进行了比较和计算,在H/C为4时,单相体系中乙炔收率最大值为98.6%,而多相体系中乙炔收率最大值为53.1%。实验考察了影响甲烷转化率、乙炔选择性、乙炔收率以及乙炔能耗的因素,分析了乙炔收率、浓度、能耗三者的关系。实验结果表明,随着甲烷进气量的增加,产品气乙炔等碳氢化合物的浓度逐渐增大,甲烷转化率、乙炔选择性以及收率呈减小趋势,乙炔能耗在出现一个最低值后开始增大。当甲烷进气量达到4.0 m3·h^-1时,得到乙炔能耗的最小值为9.68 kW·h·kg^-1,此时乙炔体积分数为11.4%,乙炔收率为86.2%。淬冷后,乙炔收率增加的最大幅度为18%,减小反应气体的停留时间使乙炔收率提高的最大幅度达到55%     

添加气对直流等离子体转化甲烷制C_2烃的影响

在低温(300~500 K)常压下,考察了不同性质的添加气二氧化碳(CO2)、氩气(Ar)和氢气(H2)(添加气摩尔浓度0%~80%)对直流冷等离子体转化甲烷制C2烃反应的影响。研究结果表明:CO2虽能在一定程度上提高甲烷转化率,但不利于C2烃的生成;Ar和H2有利于提高甲烷的转化率和C2烃选择性;添加气体对C2产物的分布研究发现:CO2有利于C2H4的生成,添加气Ar不影响产物C2烃的分布,H2在一定程度上促进了C2H4的生成;在实验考察范围内,增加体系的能量密度有利于提高甲烷的转化率;CH4-CO2体系中,C2烃选择性随能量密度的增加而升高;CH4-Ar体系中,C2烃选择性随能量密度的增加变化不大:CH4-H2体系中,C2烃的选择性随能量密度的增加呈现先升后降的趋势。     

提高等离子体裂解煤制乙炔收率的方案研究

将反应体系的温度升高到升华点以上 ,是提高等离子体裂解煤制乙炔收率的必由之路 .采用最小自由能方法研究了煤的 C- H- O热力学平衡体系 ,在此基础上提出了一种以煤层气甲烷为冷却剂的等离子体裂解煤制乙炔方案 ,初始反应体系的温度在 40 0 0 K以上 .理论的计算和分析结果表明 ,这种方案可获得较高的乙炔收率 ,而单位质量乙炔的比能耗很低 ,具有很好的经济效益和环境效益 .     

SO3体系中碘催化甲烷的选择性氧化反应

在SO3体系中,采用碘系列化合物作为催化剂进行甲烷部分氧化反应的研究.对催化剂进行筛选,考察反应工艺条件的影响,并对反应机理进行探讨.最终确定I2为最佳催化剂,反应的最优工艺条件为:催化剂0.099 mol·L-1,温度T=433K,初始压力P=4.0 MPa,搅拌速度500 r/min.该工艺条件下甲烷转化率可达63.57％,目的产物收率为52.6％,产物选择性82.74％.     

乙炔氢氯化反应体系热力学分析

对乙炔氢氯化反应体系主反应与副反应的热力学性质进行了计算。采用Aspen Plus11.1中的Gibbs反应器模块并结合Sensitivity工具对单一产物、不考虑聚合反应与考虑聚合反应3种情况下各产物在90~420℃下的平衡收率进行计算。结果表明:从热力学角度讲,各反应均为强放热反应,标准状态下能自发进行;210℃以下各反应单独进行时均能达到接近100%的转化率,随温度升高,各反应乙炔平衡转化率逐渐降低且非聚合副反应降低的最快;当考虑非聚合副反应时,氯乙烯收率仍能达到97%以上;但当考虑聚合反应时,氯乙烯收率最高仅为0.6%,主要生成氯丁二烯。表明生成的氯乙烯容易与乙炔发生串联聚合,实际反应过程中应及时将氯乙烯移除,并避免乙炔过量。反应过程中应考虑催化剂的积炭失活因素,降低积炭。     

太阳能甲烷干重整复杂反应体系的热化学储能特性

基于热力学第一和第二定律对太阳能甲烷干重整复杂反应体系的热力学特性进行建模分析,研究该体系在不同太阳光照强度时的反应器温度响应及热化学储能特性,以及副反应和各部分能量损失对整个体系能量效率的影响规律。通过平衡常数法计算反应器平衡状态时的物质组成,并进而利用热力学模型计算不同条件下入口气转化率、选择性、功效率和能量转换效率的变化规律。结果表明：进料比n(CO₂)/n(CH₄)的升高有助于提高甲烷转化率、选择性、功效率和能量转换效率;反应器温度的变化对系统热化学储能特性的影响显著,在较低温区（923～1123K）,副反应较多,且随着温度的升高副反应逐渐受到抑制,积炭减少,功效率和能量转换效率逐渐升高,并在1123K时达到峰值;温度继续升高（>1123K）,反应器辐射损失显著增加,导致功效率和能量转换效率随温度升高而降低;高温区（>1200K）,副反应受到抑制,复杂反应体系的系统效率同单一反应体系趋于一致,副反应基本对系统性能无影响。     

Rh/MgO/γ-Al2O3上的毫秒级甲烷蒸汽重整过程

采用负载型Rh/MgO/γ-Al2O3催化剂研究了毫秒级甲烷蒸汽重整过程,在水碳比为1和3的条件下,详细考察了反应温度、空速和催化剂Rh含量对反应转化率和选择性的影响。研究结果表明,Rh/MgO/γ-Al2O3催化剂在毫秒级操作条件下具有良好的催化性能,使用5%(质量分数)Rh催化剂,在水碳比3、反应温度1150K、空速641.11 L·(gcat)-1·h-1时,CH4转化率约90%,CO2选择性约20%,毫秒级接触时间反应行为即可接近热力学平衡。高温有利于毫秒级甲烷蒸汽重整过程。     

负载型纳米金催化剂在乙炔选择性加氢反应中的研究进展

介绍了乙炔选择性加氢制乙烯催化剂的研究和开发进展。针对负载型纳米金催化剂的发展趋势及其对乙炔加氢反应产物中乙烯的独特选择性,重点对比单金属纳米金催化剂及合金型催化剂的催化性能差异,发现合金型纳米金催化剂具有较高的乙炔转化率和稳定性。影响催化性能的主要因素有纳米粒子的大小及活性组分之间的相互协同作用。分析积炭的形成以及导致催化剂失活的原理。展望低温条件下具有高转化率与高稳定性的合金型纳米金催化剂的应用前景。     

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。