A cold vent is an area where methane-rich fluid seepage occurs. This seepage may alter the local temperature, salinity, and subsequent accumulation of the gas hydrate. Using a kinetic gas hydrate formation model and i...A cold vent is an area where methane-rich fluid seepage occurs. This seepage may alter the local temperature, salinity, and subsequent accumulation of the gas hydrate. Using a kinetic gas hydrate formation model and in situ measurement of tempera- ture, salinity and fluid flux at the southern summit of Hydrate Ridge, we simuIate the gas hydrate accumulation at three distinct fluid sites： clam, bacterial mat, and gas discharge sites. At the clam sites （pore water flux 〈 20 kg m-2 yr-1）, pore water advec- tion has little influence on temperature and salinity. However, the salinity and temperature are increased （peak salinity 〉 0.8 tool kg-1） by the formation of gas hydrate causing the base of the hydrate stability zone to move gradually from -115 to -70 meters below seafloor （mbsf）. The gas hydrate saturation at the clam sites is relatively high. The water flux at the bacterial mat sites ranges from 100 to 2500 kg m-2 yr-1. The water flow suppresses the increase in salinity resulting in a salinity close to or slightly higher than that of seawater （〈 0.65 mol kg-l）. Heat advection by water flow increases temperature significantly, shifting the base of the hydrate stability zone to above 50 or even 3 mbsf. The gas hydrate saturation is relatively low at the bacterial mat site. At the gas discharge sites, the pore water flux could reach 10^10 kg m-2 yr-1, and the temperature could reach that of the source area in 9 min. There is no gas hydrate formation at the gas discharge sites. Our simulative analysis therefore reveals that a lower pore water flux would result in lower salinity, higher temperature, and a shallower base of the hydrate sta- bility zone. This in turn induces a lower gas hydrate formation rate, lower hydrate saturation, and eventually less gas hydrate resources.展开更多
This paper aims at solving the problems of low thermal collection rate,inconvenient maintenance,hindering indoor using during the application of passive solar technologies in rural houses in severe cold region.All the...This paper aims at solving the problems of low thermal collection rate,inconvenient maintenance,hindering indoor using during the application of passive solar technologies in rural houses in severe cold region.All these defects prevent the passive solar houses' further development. This paper chooses trombe wall,which has higher thermal efficiency of the passive solar house,as research object. The traditional vent is improved into a new type of ventilation device. This improvement overcomes the shortcoming,which traditional vent loses huge heat,and simplifies the construction of vent. Comparing with traditional trombe wall,the energy saving rate is 15. 69%.展开更多
总结了油气田冷放空设计的原则和依据,以及放空气体大气扩散的主要影响因素。基于冷放空的本质和流体的物性,引用了射流理论的密度弗劳德数定义式来描述放空气扩散运动的特征。分别介绍了API Standard 521和流体动力学中放空气浓度和扩...总结了油气田冷放空设计的原则和依据,以及放空气体大气扩散的主要影响因素。基于冷放空的本质和流体的物性,引用了射流理论的密度弗劳德数定义式来描述放空气扩散运动的特征。分别介绍了API Standard 521和流体动力学中放空气浓度和扩散距离的关系式,阐述了确定冷放空管尺寸和高度的方法。介绍了雷诺数判据和密度弗劳德数定义式在扩散模拟分析中的应用。基于对理查逊数用于Pasquill大气稳定度的研究成果,提出了使用CFD软件模拟放空气扩散时大气环境的模拟方法。最后通过软件仿真计算结果对比了放空口水平朝向和垂直朝向对扩散的不同影响。展开更多
南海东沙东北部碳酸盐岩和泥质沉积物中的生物标志化合物组合及其碳同位素组成分析表明,研究区内甲烷缺氧氧化作用(anaerobic oxidation of methane-AOM)发育。研究区内碳酸盐岩中含丰富的AOM标志化合物,2,6,11,15-四甲基十六烷(Croceta...南海东沙东北部碳酸盐岩和泥质沉积物中的生物标志化合物组合及其碳同位素组成分析表明,研究区内甲烷缺氧氧化作用(anaerobic oxidation of methane-AOM)发育。研究区内碳酸盐岩中含丰富的AOM标志化合物,2,6,11,15-四甲基十六烷(Crocetane-Cr.)、2,6,10,15,19-五甲基番茄烷(Pentamethylicosane-PMI)和2,6,10,15,19,23-六甲基二十四烷(Squalane-Sq角鲨烷)的13C亏损强烈(δ13C值介于-74.2‰^-119.0‰PDB之间),表明碳酸盐岩形成于AOM,同时反映该研究区曾发生过强烈、持续的富CH4流体释放活动。柱状泥质沉积物中,AOM生物标志化合物在硫酸岩-甲烷过渡带(SMI—Sulfate-Methane Interface)边界附近相对丰度高,SMI之上样品中含量低,或未检出,表明现代环境在SMI附近有大量嗜甲烷微生物生长,使得深部上升的甲烷被大量消耗,很少有甲烷逸出海底。AOM生物标志化合物可用来指示SMI边界。不同站位、不同岩性AOM生物标志化合物组成(包括碳同位素组成)的差异反映了嗜甲烷古细菌组成的不同。展开更多
基金supported by National Basic Research Program of China (Grant No.2009CB219508)Chinese Academy of Sciences (Grant No.KZCX2-YW-GJ03)+2 种基金National Natural Science Foundation of China (GrantNos. 91228206 & 40725011)GIGCAS 135 Program (Grant No.Y234021001)Scientific and Technological Program of Guangdong Province (Grant No. 2011A080403021)
文摘A cold vent is an area where methane-rich fluid seepage occurs. This seepage may alter the local temperature, salinity, and subsequent accumulation of the gas hydrate. Using a kinetic gas hydrate formation model and in situ measurement of tempera- ture, salinity and fluid flux at the southern summit of Hydrate Ridge, we simuIate the gas hydrate accumulation at three distinct fluid sites： clam, bacterial mat, and gas discharge sites. At the clam sites （pore water flux 〈 20 kg m-2 yr-1）, pore water advec- tion has little influence on temperature and salinity. However, the salinity and temperature are increased （peak salinity 〉 0.8 tool kg-1） by the formation of gas hydrate causing the base of the hydrate stability zone to move gradually from -115 to -70 meters below seafloor （mbsf）. The gas hydrate saturation at the clam sites is relatively high. The water flux at the bacterial mat sites ranges from 100 to 2500 kg m-2 yr-1. The water flow suppresses the increase in salinity resulting in a salinity close to or slightly higher than that of seawater （〈 0.65 mol kg-l）. Heat advection by water flow increases temperature significantly, shifting the base of the hydrate stability zone to above 50 or even 3 mbsf. The gas hydrate saturation is relatively low at the bacterial mat site. At the gas discharge sites, the pore water flux could reach 10^10 kg m-2 yr-1, and the temperature could reach that of the source area in 9 min. There is no gas hydrate formation at the gas discharge sites. Our simulative analysis therefore reveals that a lower pore water flux would result in lower salinity, higher temperature, and a shallower base of the hydrate sta- bility zone. This in turn induces a lower gas hydrate formation rate, lower hydrate saturation, and eventually less gas hydrate resources.
基金Sponsored by the National Science-Technology Support Plan Projects (Grant No.2011BAJ08B06-2)
文摘This paper aims at solving the problems of low thermal collection rate,inconvenient maintenance,hindering indoor using during the application of passive solar technologies in rural houses in severe cold region.All these defects prevent the passive solar houses' further development. This paper chooses trombe wall,which has higher thermal efficiency of the passive solar house,as research object. The traditional vent is improved into a new type of ventilation device. This improvement overcomes the shortcoming,which traditional vent loses huge heat,and simplifies the construction of vent. Comparing with traditional trombe wall,the energy saving rate is 15. 69%.
文摘总结了油气田冷放空设计的原则和依据,以及放空气体大气扩散的主要影响因素。基于冷放空的本质和流体的物性,引用了射流理论的密度弗劳德数定义式来描述放空气扩散运动的特征。分别介绍了API Standard 521和流体动力学中放空气浓度和扩散距离的关系式,阐述了确定冷放空管尺寸和高度的方法。介绍了雷诺数判据和密度弗劳德数定义式在扩散模拟分析中的应用。基于对理查逊数用于Pasquill大气稳定度的研究成果,提出了使用CFD软件模拟放空气扩散时大气环境的模拟方法。最后通过软件仿真计算结果对比了放空口水平朝向和垂直朝向对扩散的不同影响。
文摘南海东沙东北部碳酸盐岩和泥质沉积物中的生物标志化合物组合及其碳同位素组成分析表明,研究区内甲烷缺氧氧化作用(anaerobic oxidation of methane-AOM)发育。研究区内碳酸盐岩中含丰富的AOM标志化合物,2,6,11,15-四甲基十六烷(Crocetane-Cr.)、2,6,10,15,19-五甲基番茄烷(Pentamethylicosane-PMI)和2,6,10,15,19,23-六甲基二十四烷(Squalane-Sq角鲨烷)的13C亏损强烈(δ13C值介于-74.2‰^-119.0‰PDB之间),表明碳酸盐岩形成于AOM,同时反映该研究区曾发生过强烈、持续的富CH4流体释放活动。柱状泥质沉积物中,AOM生物标志化合物在硫酸岩-甲烷过渡带(SMI—Sulfate-Methane Interface)边界附近相对丰度高,SMI之上样品中含量低,或未检出,表明现代环境在SMI附近有大量嗜甲烷微生物生长,使得深部上升的甲烷被大量消耗,很少有甲烷逸出海底。AOM生物标志化合物可用来指示SMI边界。不同站位、不同岩性AOM生物标志化合物组成(包括碳同位素组成)的差异反映了嗜甲烷古细菌组成的不同。
