共查询到19条相似文献,搜索用时 93 毫秒
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新型空调蓄冷材料四丁基溴化铵-水相变条件和相变热实验研究 总被引:3,自引:0,他引:3
四丁基溴化铵水溶液在适当的浓度范围内可在常规空调冷冻水温区内发生固-液相变,形成半笼水合物,是一种潜在的空调蓄冷理想材料.利用实验室的水合物形成实验装置测量了四丁基溴化铵水溶液固-液相变条件,实验结果表明当溶液的质量浓度低于45%时,相变温度随着溶液浓度的增大而增大,但当溶液浓度超过25%,相变温度增加的幅度减小.四丁基溴化铵水溶液的浓度超过45%后,其固一液相变温度反而下降.利用DSC测量了四丁基溴化铵水溶液的相变热,相变热达到195.9kJ/kg. 相似文献
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实验中将相变微胶囊乳液与聚乙烯醇(PVA)溶液复合,通过物理发泡法制得具有形状记忆性能的多孔定形复合相变材料,研究了相变微胶囊对多孔定形复合相变材料孔结构及吸水保水性、相变性能、形状记忆性能等的影响。结果表明,所制备多孔定形复合相变材料的孔结构随着微胶囊乳液用量的增大出现并泡现象,孔径与开孔率增大;吸水率与保水率明显提高,吸水率最大可达1025%;相变焓值随相变微胶囊乳液用量的增大而增大,可达10.85 J/g,具有良好的相变储热性能;多孔定形复合相变材料经弯折形变固定后,热致形变回复率5 min内可达77.8%,湿致形状回复率在1 min内可达到83.3%,具有较好的形状记忆特性。 相似文献
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《中国计量学院学报》2016,(3):276-280
煤炭自燃是我国煤矿生产和煤炭储运过程中重要的事故灾害之一.今基于表征体元(REV)尺度的格子Boltzmann方法,建立了模拟煤氧物理吸附过程的模型,对煤氧吸附的相关特性进行了定性研究.数值模拟的结果表明,煤炭的孔隙度和环境温度对煤体多孔介质的物理吸氧量有显著的影响,吸氧量随着孔隙度的增大而逐渐增加,随着温度的升高而逐渐减小,这与先前学者研究所得相吻合. 相似文献
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由美国地质勘探局(USGS)和碳氢化合物管理总局领导的一个考察队正在印度近海进行天然气水合物的研究与勘探,后者是印度石油与天然气部的一个下属机构。科学家们进行了海洋钻探、提取岩芯、实行航测并进行分析以便对地质储量、地域构造及天然气水合物的矿床特征进行评估。 相似文献
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随着海底矿物开采越来越普遍,技术人员面对越来越复杂的钻探技术挑战。特别是极端条件下的深海开采,开采矿产之前,要先处理好表层的可燃冰。通过PVT仪器直接目测来观察气体水合物的形成是一种比较常用的方法。通过记录测量过程中的温压变化来确定气体水合物的形成热力学条件。但是笨重的PVT仪使得实验受限制,并且实验过程中不能有固体微粒出现。本文通过微量热法来确定水合物的成分,研究形成及分解机理,测量比热容。为了满足高压微量热试验需求,法国塞塔拉姆公司特别提出了完全革新的测试手段(法国石油学会专利技术),运用高压MICRODSC来建立气体水合物的形成热力学模型及生成动力学理论,表征水合物相变与时间、温度、压力的对应关系。MicroDSCVII是研究气体水合的专业高压微量热仪,一经推出就广受好评,样品量为0.7ml的全新样品池,并可与专业的高压控制面板相接,最大压力可以达到1000bars,温度范围为-45℃andl20℃。目前,高压MicroDSCVII已经被运用于各种条件下的气体水合物研究,诸如:气体水合物的形成机理,特别是甲烷气体水合物的研究;气体水合物在海底沉积物中的成藏机理;石油开采中水合物形成的抑制;天然气运输及储存过程中气体水合物的形成;冷藏过程中的气体水合的形成及分解等。 相似文献
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新型畜冷工质气体水合物研究现状及其应用 总被引:1,自引:1,他引:1
介绍了新型畜冷工质气体水合物以及制冷剂气体水合物的理论研究现状。总结了气体水合物畜冷的影响因素,重点介绍气体水合物畜冷装置研究应用。提出今后的研究重点。 相似文献
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One of the new approaches for capturing carbon dioxide from treated flue gases (post-combustion capture) is based on gas hydrate crystallization. The basis for the separation or capture of the CO(2) is the fact that the carbon dioxide content of gas hydrate crystals is different than that of the flue gas. When a gas mixture of CO(2) and H(2) forms gas hydrates the CO(2) prefers to partition in the hydrate phase. This provides the basis for the separation of CO(2) (pre-combustion capture) from a fuel gas (CO(2)/H(2)) mixture. The present study illustrates the concept and provides basic thermodynamic and kinetic data for conceptual process design. In addition, hybrid conceptual processes for pre and post-combustion capture based on hydrate formation coupled with membrane separation are presented. 相似文献
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The present work investigates TBPB (tetra-n-butylphosphonium bromide) hydrate slurries based on focused beam reflectance measurement (FBRM) method. Hydrates can be used as phase change materials (PCM) for thermal energy storage due to their high latent heat of melting. In this study, hydrates were formed from TBPB-water mixtures, suitable for air-conditioning applications. Moreover, hydrate slurries, composed of hydrate-particles dispersed in liquid, are appropriate solutions for cold distribution. Nevertheless, flow properties of hydrate slurries, depending on hydrate crystallization kinetics, must be controlled. In this work, FBRM was used for analysing TBPB-hydrate-particle size distribution. This work showed that FBRM can detect system phase changes (nucleation, growth, agglomeration). In addition, a bimodal distribution of particles was observed. This work could be useful to understand rheological behaviour of hydrate slurry, not only for secondary refrigeration applications, but also for natural gas hydrate transportation, pipeline plugging prevention, and gas capture. 相似文献
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《工程(英文)》2018,4(3):321-329
Gas hydrates are solid inclusion compounds that are composed of a three-dimensional hydrogen-bonded network of water cages that can trap small gas molecules, such as methane and carbon dioxide. Understanding the rheological properties of gas hydrate crystals in solution can be critical in a number of energy applications, including the transportation of natural gas in subsea and onshore operations, as well as technological applications for gas separation, desalination, or sequestration. A number of experimental and modeling studies have been done on hydrate slurry rheology; however, the link between theory and experiment is not well-defined. This article provides a review on the current state of the art of hydrate slurry viscosity measurements from high- and low-pressure rheometer studies and high-pressure flowloops over a range of different sub-cooling (ΔTsub = Tequil − Texp) and fluid conditions, including for water and oil continuous systems. The theoretical models that have been developed to describe the gas hydrate slurry relative viscosity are also reviewed. Perspectives’ linkage between the experiments and theory is also discussed. 相似文献
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Some current challenges in clathrate hydrate science: Nucleation,decomposition and the memory effect
《Current Opinion in Solid State & Materials Science》2016,20(6):344-351
Among outstanding issues still to be understood regarding the clathrate hydrates are the mechanism of the processes involved in the formation and decomposition of clathrates: nucleation, decomposition, and the memory effect during reformation. The latter involves the shorter induction times required for solutions of decomposed hydrate to nucleate as compared to those for freshly prepared solutions. The formation of the clathrate hydrate phases of insoluble gases in water is accompanied by a ∼6000 fold concentration of the gas content in the solid phase compared to the aqueous phase from which it forms. The nucleation mechanism for the solid hydrate which allows the delivery of such high concentration of gas and water in one location has been the subject of much experimental and computational study. While these studies have improved our understanding of the nucleation process, many unknown aspects remain. These developments are described in this Opinion. 相似文献
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为研究双层连续管内管举升水合物的井筒多相流动规律,建立了采用双层连续管固态流化开采天然气水合物的井筒多相流动模型,采用有限差分法对模型进行求解。基于以上模型,对南海某实例井采用双层连续管固态流化开采天然气水合物的井筒多相流动行为进行了模拟。研究结果表明,随着流体上升,双层连续管内管温度和压力逐渐降低;在海底 1 600 米至 700 米时,固相含量以及液相含量相对稳定,含气率为 0;当流体上升至 700 多米的高度时,固相水合物开始逐渐分解。当钻井液密度与排量过高或者过低,都会使得井底压力脱离安全窗口,威胁到井控安全。因此,合理地选用钻井参数,对确保井控安全尤为重要。 相似文献
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水合物技术应用可归纳为分解应用和生成应用,本文就这两大应用方向对水合物进行了分类综述。从水合物分解角度,阐述了天然气水合物资源勘探开发、管道水合物解堵、水合物抑制防控等技术应用的研究进展;从水合物分解的逆过程(生成)角度,阐述了水合物储气、二氧化碳捕获与封存、海水淡化、溶液提浓、污水处理、混合气体分离、蓄冷等应用技术。同时论文结合气体水合物发展历程,概括了气体水合物技术在诸多领域的应用,指出了水合物技术发展取得的诸多成果,也提出了新形势下水合物发展所面临的问题,希望能为今后水合物技术的发展带来一定指导。 相似文献