天然气水合物的研究现状与发展趋势

介绍了天然气水合物的形成机制,阐述了天然气水合物作为新型清洁能源的巨大潜在价值;国内外对天然气水合物的研究进展。介绍了天然气水合物在开采中可能存在的环境问题,对比了热激发开采法、减压开采法以及化学试剂注入开采法等开采方式的优劣。介绍了天然气水合物在储运天然气以及作为汽车燃料方面的发展趋势,并对天然气水合物的未来市场前景进行了展望。     

二氧化碳置换法开采天然气水合物的研究现状

天然气水合物在开采过程中形态会发生变化，从固态变为液态和气态，即发生相变。因此，水合物的开采原理主要是围绕改变水合物稳定存在的条件(温度和压力为主要因素),促使水合物分解，从而产生天然气。目前，天然气水合物开采技术主要有注热法、降压法、化学试剂法和二氧化碳置换法。其中，二氧化碳置换法开采天然气水合物具有十分重要的现实意义。这种方法可以弥补传统开采方法的不足，并有望成为未来工业化天然气水合物开采的主要技术之一。     

二元复合技术开采天然气水合物可行性分析

目前常规的天然气水合物开采方法均处于试验阶段,针对单一开采方法均表现出不同程度的缺点,本文提出了一种二元复合的开采天然气水合物技术。通过对现有的五种常规开采方法进行二元随机组合,在技术、经济、环境安全可行性等几个方面上对组合后的十种方法进行理论可行性分析。结果显示热采联合降压法、热采联合地面分解法、热采联合置换法、注抑制剂联合地面分解法、注抑制剂联合置换法初步显示具有较好的理论可行性,对于剩余的五类二元复合开采方法,由于经济效益差、环境污染大、安全可控系数低等条件限制,目前还不具备理论可行性。提出了二元复合开采天然气水合物的理论技术思路,并通过对二元复合开采技术进行理论分析,总结出较目前常规单一开采方法具有一定理论优势的开采技术,以期为天然气水合物的稳定试采研究提供借鉴意义。     

天然气水合物资源开采方法研究

自然界中存在大量的水合物,这些水合物已经被认为是将来重要的能源,本文分析了天然气水合物资源的特点,并综合介绍了现阶段提出的天然气水合物开采方法及模型,对比分析了典型开采方法,如热激发、降压和注抑制剂等的优缺点和经济性,评述了研究中存在的问题,并提出了今后研究的重点。     

天然气水合物勘探与开发研究进展

天然气水合物的勘探技术主要包括似海底反射层、钻孔取芯和测井方法，天然气水合物的开采技术则包括热激发法、降压法和化学剂法。但由于天然气水合物的赋存状态与物化性质，开采时可能会加深全球温室效应、钻井平台及海底滑塌等问题，致使国际上天然气水合物的开采技术研究比较缓慢，目前仍处于探索实验性开采阶段。据有关专家预测，开采技术一旦被突破，日本或美国将在2010年以后，率先实现天然气水合物的商业生产。     

天然气水合物的有效能量及CO_2排放强度分析

与天然气、石油、煤等常规化石能源以富集态赋存、以赋存态开采不同,天然气水合物大都以固态分散赋存于地层的孔隙中,对其中所含天然气的开采要求水合物的原位分解。天然气水合物原位分解需要能量输入,既包括水合物的分解焓,也包括水合物和多孔地层(介质)升温所需的热量。由于天然气水合物的赋存条件差异很大,开采时水合物和多孔地层升温所需的热量不同,一些条件下天然气水合物的可利用能量(有效能量)会远低于常规天然气,单位有效能量所产生的总CO2排放量甚至会高于石油和煤。为了量化认识这个现象,本文进行了天然气水合物开采能耗的热力学计算,分析了水合物赋存状况与产出天然气的有效(净)能量的关系,计算和讨论了不同赋存条件下天然气水合物在热能利用过程中的二氧化碳排放强度,并与常规化石能源进行了对比。     

我国可燃冰开采研究取得重要进展

中国科学院广州能源研究所天然气水合物中心承担的中科院知识创新工程方向性项目———天然气水合物 (可燃冰 )开采中若干关键问题的研究 ,在天然气水合物在多孔介质中的形成 /分解条件、外场控制天然气水合物分解速度、化学药剂对天然气水合物分解的影响、天然气水合物热物理性质等相关基础研究方面取得了重要进展。据介绍 ,天然气水合物俗称“可燃冰” ,是近 2 0年来在海洋和冻土带发现的新型洁净优质能源 ,资源量巨大。近几年初步调查证实我国海域存在“可燃冰” ,这为我国研究和开发清洁天然气水合物能源展示出美好前景。目前 ,国际上对…     

天然气水合物置换开采的能源效率研究

天然气水合物分解是一个相变过程，开采时涉及各种形式能量的消耗和转化，如电能、化学能、热能等。为了科学地评价天然气水合物开采技术的经济性，建立了以有效能（）为核心的能源效率计算方程，并以CO₂置换法开采天然气水合物为例，介绍任意生产周期内能源效率的计算方法和流程框图。在CO₂置换开采天然气水合物的工艺过程中，注气量、产气量和产气中甲烷含量是三个关键参数，将产气量与注气量之比定义为采注比，分析采注比及产气中甲烷含量对能源效率的影响。结果表明：在设定条件下CO₂置换开采天然气水合物的整体能源效率介于0.31～6.4之间；增大采注比，有利于提高能源效率；产气中甲烷的摩尔分率越高，气体分离的能耗越低，能源效率也可显著提高。因此，调控产气量和产气中甲烷摩尔分率是提高CO₂置换法能源效率的主要途径。通过所建立的能效计算方程为天然气水合物开采工艺的优化提供指导。     

天然气水合物热采数值模拟研究

天然气水合物是一种重要的新型能源。在数值模拟方面,目前国内还没有较完善的天然气水合物注热开采数值模拟软件。本文在调研了国内外关于天然气水合物开采的数学模型的基础上,建立三维三相五组分水合物注热开采数学模型,模型中特别考虑了盐这种抑制剂对水合物分解的影响。模型中包含:各组分质量守恒方程,能量守恒方程,水合物分解动力学方程;考虑了气水两相渗流过程、热对流、热传导,更兼顾考虑了水合物层与盖底层的热交换的影响,使模型更完善。     

注热水盐度对水合物开采影响的实验研究

天然气水合物是目前备受关注的新型洁净优质能源,注热盐水是一种有效的开采方式。采用自制的一维天然气水合物(NGH)开采模拟实验装置,首先在填砂模型中生成初始条件相同的天然气水合物藏,之后注入盐度为2%、10%、20%的热水进行开采实验。结果表明:当注热水盐度较大(达到10%后)时,水合物快速分解,与自由气同时产出,产气速率峰值较大;而当注热水盐度较小(2%)时,自由气首先产出,然后水合物分解气体产出。注热水盐度越大,水合物分解速度越快,热前缘移动速率越大,水合物大量分解阶段的能量效率越高。因此,注热水盐度的增加可以加快天然气水合物的开采速率,增大注热开采的经济可行性。     

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.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

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。     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.