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Fundamental study of impurities influence on hydrate nuclaeation

杂质对水合物成核影响的基础研究

基本信息

批准号：
18560775
负责人：
YAMANE Kenji
金额：
$ 2.57万
依托单位：
National Maritime Research Institute
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

It is important to elucidate the knowledge of hydrate nucleation for not only hydrate basic field but also engineering and industrial field. However the knowledge of hydrate nucleation is lacked due to the difficulty of formation of hydrate even under the suitable pressure and temperature conditions on the phase diagram experimentally.The objective of the present study is to elucidate the conditions which influence on hydrate nucleation. In this study, we used the liquid CO_2 related to the ocean as a guest and measured the induction time under the various conditions of the surrounding water as a host (temperature, dissolved CO_2 concentration, and initial H_2O cluster)We measured the time from putting liquid CO_2 droplet into the pressure chamber (30MPa, 3〜5℃) to forming the hydrate film. Relationship between dissolved CO_2 concentration, water temperature in the chamber and induction time was evaluated respectively and following results were obtained.・The relation between CO_2 concen … More tration and induction time wasn't confirmed.・There is the tendency that the lower temperature and the larger volume of putted liquid CO_2 droplet cause the shorter the induction time.We putted liquid CO_2 droplet and measured the induction time after the temperature and pressure history of a host water side have been changed, (Initial H_2O cluster have been changed) We obtained following results.・In the case of using the water that had previously left under the atmospheric pressure and low temperature, hydrate formation was hardly observed.・In the case of using the water that had previously frozen as ice and melted at atmospheric pressure, hydrate formation was not observed.・In the case of using the water that had previously frozen as ice and melted at hydrate formation pressure, hydrate formation was identified. In addition the ratio of melted water weight was changed. The lager quantity of melted water causes the shorter the induction time.From above knowledge, we elucidated that CO_2 concentration hardly influence on hydrate nucleation in the range of CO_2 concentration of this study and the condition of H_2O cluster of the host water side may influence on hydrate nucleation greatly. Less

阐明水合物成核知识不仅对于水合物基础领域而且对于工程和工业领域都具有重要意义。然而，由于即使在实验相图上合适的压力和温度条件下也难以形成水合物，因此缺乏水合物成核的知识。本研究的目的是阐明影响水合物成核的条件。本研究以与海洋相关的液态CO_2为客体，测量了以周围水为主体的各种条件（温度、溶解CO_2浓度、初始H_2O簇）下的诱导时间，测量了从将液态CO_2液滴放入压力室（30MPa，3〜5℃）到形成水合物膜的时间。分别评估了溶解CO_2浓度、室内水温和诱导时间之间的关系，得到了以下结果。・CO_2浓度和诱导时间之间的关系尚未确定。・存在温度越低、投入的液态CO_2液滴体积越大，诱导时间越短的趋势。我们投入液态CO_2液滴，在主机水侧的温度和压力历史记录之后，测量了诱导时间。改变，（初始H_2O簇已改变）我们得到了以下结果。・使用先前在大气压和低温下放置的水的情况下，几乎观察不到水合物的形成。・使用先前冻结为冰并在大气压下融化的水的情况下，未观察到水合物的形成。・使用先前冻结为冰并在水合物形成压力下熔化的水的情况下，水合物的形成被观察到。确定。另外，改变了融化水重量的比例。融水量越大,诱导时间越短。由以上认识,我们阐明在本研究的CO_2浓度范围内,CO_2浓度对水合物成核几乎没有影响,而主体水侧H_2O团簇的状况可能对水合物成核影响较大。较少的