现代暖期气候变暖对南海北部陆坡天然气水合物分解潜在影响     

贾永刚  阮文凤  胡乃利  乔玥  李正辉  胡聪 《地学前缘》2022,29(4):191-201

现代暖期(Current Warm Period,CWP,1850—至今)以来全球气温升高,南海北部陆坡底层海水温度升高、海平面上升影响海底天然气水合物稳定性。为探究现代暖期气候变暖对南海北部陆坡水合物分解影响,本文模拟计算了东沙海域、神狐海域、西沙海域、琼东南海域水合物赋存水深最浅处水合物的饱和度在1 000年内变化情况,评估了受现代暖期气候变暖影响水合物赋存水深范围,讨论了水合物分解量及其对环境影响。结果发现:(1)受现代暖期气候变暖影响,东沙海域、西沙海域、琼东南海域水合物分解,神狐海域水合物不分解;当东沙海域、西沙海域、琼东南海域水深分别超过665、770、725 m,水合物不分解;(2)现代暖期自始以来,南海北部陆坡水合物分解量为9.36×10⁷~3.83×10⁸ m³,产生的甲烷量为1.54×10¹⁰~6.28×10¹⁰ m³;(3)受现代暖期气候变暖影响,南海北部陆坡每年水合物分解量为5.5×10⁵~2.25×10⁶ m³,产生的甲烷量为9.02×10⁷~3.69×10⁸ m³,这些甲烷中3.61×10⁵~1.48×10⁶ m³能够进入大气,对温室效应贡献度为每年我国人类生活的0.01%~0.06%;与此同时,1.77×10⁷~7.23×10⁷ m³甲烷可能会在海水中被氧化形成弱酸,加重南海北部陆坡海水酸化。  相似文献   

Model test of stratum failure and pore pressure variation induced by THF hydrate dissociation     

Tao Liu  Lei Zhou  Hai-lei Kou  Mei-xin Zhang 《Marine Georesources & Geotechnology》2013,31(5):539-546

ABSTRACT

A model test program for studying soil stratum failure and pore pressure variation during tetrahydrofuran (THF) hydrate dissociation considering the effects of heating and drainage conditions is presented in this paper. The temperature and pore pressures are recorded during heating. Test results show that the THF hydrate would dissociate to be liquid and then gas when heating. Once pore pressure generated by the flow of released gas/water exceeded the strength of over layer, the layered fractures and soil-gas/water mixture outburst would occur. The high heating temperature and low permeability of over layer both cause excess pore pressure generation and more serious stratum failures.  相似文献   

新型常压热解离化学电离装置的研制及应用   总被引：1，自引：1，他引：0  

欧阳永中  韩京  鲍廷义  贾滨  李超  汪志成 《岩矿测试》2012,31(1):64-70

为了克服常压热解离化学电离装置(TDCI)热源控制不稳定、背景干扰较大、实验重现性相对较差等问题。文章在前期研究的基础上,分别对仪器各组成部件进行优化和改进,研制出能够根据待测物的热稳定性、极性、挥发性、熔点等性质,能够对仪器的温度、加热时间、加速电压等仪器参数连续、精确可调的新型常压热解电离源实验装置,并进行了优化和表征。与原研制的TDCI实验装置相比,新型TDCI电离装置的高压调节和温度控制的连续性和精确度以及热源的稳定性得到了极大的提高。高压调节的最小刻度从原来的1 V减小到0.1 V,温度控制系统的调控精确由原来的±5℃减小到±1℃。采用新型TDCI-MS技术,在常压和无需样品预处理的条件下,实现了实际样品可乐中痕量兴奋剂可卡因和牛奶中弱极性物质三聚氰胺的快速检测,单个样品检测时间都小于30 s,检出限低,可卡因和三聚氰胺的最低检出限分别为1.12×10^-12 g/mL和2.62×10^-11 g/mL,重现性好,相对标准偏差(RSD)为4.61%~9.80%,优于原TDCI电离装置的检测结果,完全满足实际样品的检测需要。由于其具有独立稳定的加热装置,与表面解吸常压电离源相比,本仪器装置更适于难挥发性化合物的快速分析。  相似文献   

Bond dissociation energies and bond orders for some astrophysical molecules     

R. R. Reddy  R. Viswanath 《Journal of Astrophysics and Astronomy》1989,10(2):157-160

The bond dissociation energies for astrophysically important diatomic molecules have been estimated based on the derived relation D_AB = D_AB + 32.058 Δ_χ where D_AB = (D_AA D_BB)1/2, Δ_χ represents Pauling electronegativity difference χ_A – χ_B) Based on the formula suggested by Reddyet al., bond orders are estimated. The ambiguity arising from Parr & Borkman relation is discussed. The present study supports the view of Politzer thatq/(0.5r _e)² is the correct definition of bond order. The estimated bond energies are in reasonably good agreement with the values in the literature. The bond energies estimated with the relation we suggested, for the molecules in the present study, give an error of 8.0 per cent. The corresponding error associated with Pauling’s equation is 26.8 per cent.  相似文献   

2-[2-(5-甲基苯并噻唑)偶氮]-5-二乙氨基苯甲酸的离解平衡及其与铁的显色反应     

张教强  樊学忠  张国防 《岩矿测试》1999,18(3)

研究了新显色剂２－［２－（５－甲基苯并噻唑）偶氮］－５－二乙氨基苯甲酸（５－Ｍｅ－ＢＴＡＥＢ）的离解平衡及与Ｆｅ２＋形成配合物的条件。在十二烷基硫酸钠的存在下,５－Ｍｅ－ＢＴＡＥＢ与Ｆｅ２＋形成稳定的蓝紫色２∶１配合物,其最大吸收波长为６４０ｎｍ,表观摩尔吸光系数为１．０３×１０５Ｌ·ｍｏｌ－１·ｃｍ－１。Ｆｅ２＋的质量浓度在０～４８０μｇ／Ｌ时服从比尔定律。方法用于部级铝合金标样中微量铁的测定,结果与推荐值相符,对ｗ（Ｆｅ）为０．１％～０．５％的样品测定１０次,ＲＳＤ在０．８５％～１．９５％,用于测定矿泉水中ｗ（Ｆｅ）／１０－６铁的测定,ＲＳＤ＜１．５％（ｎ＝７）,加标回收率９８．９％～９９．４％  相似文献   

水合物地层中考虑相变的轴对称热传导问题     

张旭辉  鲁晓兵  李清平  姚海元  赵京  王爱兰 《地学前缘》2012,19(4):327-333

沉积层中水合物热分解是一个含有水合物相变的热传导过程,相变界面的演化过程是水合物分解规律及相关灾害分析的最基本问题。文中在试验观测和分析实际物理过程的基础上,建立了水合物沉积层中混相多相变阵面多区域的热传导理论模型,并针对轴对称问题进行了系列数值模拟;模型试验测定了四氢呋喃水合物沉积物中不同热源温度下水合物相变阵面的演化过程。通过对比,水合物分解相变阵面扩展的数值与试验结果吻合较好。  相似文献   

饱和粗砂、粉土内甲烷水合物形成与分解过程中的水分迁移规律          下载免费PDF全文

张鹏  吴青柏  王英梅 《地球物理学报》2011,54(4):1071-1078

用可探测土壤水分变化的pF-meter探头组装了新型水合物研究设备,并对两种饱和介质内甲烷水合物形成与分解过程中的水分迁移规律进行研究,以期望能为进一步探索多孔介质内甲烷水合物形成与分解机制提供参考.通过实验发现相同条件下,不同饱和介质内生成的甲烷水合物形态存在较大差异,且形成过程中的水分迁移规律也不同;水合物分解过程...  相似文献   

Gas outburst with sediments because of tetrahydrofuran hydrate dissociation          下载免费PDF全文

Xuhui Zhang  Xiaobing Lu  Ming Xiao 《国际地质力学数值与分析法杂志》2015,39(17):1884-1897

Methane hydrate (MH) is a new energy resource in the 21^st century. But the dissociation of MH from sediments during the MH exploration or oil/gas exploration under a hydrate layer accompanied by the softening of soils and formation of excess pore gas pressure may lead to ground failures and environmental disasters. In this study, experiments on modeling the weakening and failure of the sediment by heat‐induced dissociation of tetrahydrofuran (THF) hydrate were presented. The failure mode of gas outburst was observed. Gas outbursts is a process where gas and soils in hydrate‐dissociation zone burst out after the continuous skeleton of over‐layer is fractured during the expansion of the dissociation zone and the formation of gas zone and excess pore gas pressure. An analytical method is presented by decoupling heat transfer and soil deformation. The geometrical and mechanical similarities for gas outburst are obtained. An empirical criterion for the occurrence of outburst is proposed using the theory of thermal conduction, rigid plastic mechanics, and the experimental data. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Nuclear magnetic resonance study of the formation and dissociation process of nature gas hydrate in sandstone     

《China Geology》2022,5(4):630-636

In this work, the authors monitored the formation and dissociation process of methane hydrate in four different rock core samples through nuclear magnetic resonance (NMR) relaxation time (T₂) and 2D imaging measurement. The result shows that the intensity of T₂ spectra and magnetic resonance imaging (MRI) signals gradually decreases in the hydrate formation process, and at the same time, the T₂ spectra move toward the left domain as the growth of hydrate in the pores of the sample accelerates the decay rate. The hydrate grows and dissociates preferentially in the purer sandstone samples with larger pore size and higher porosity. Significantly, for the sample with lower porosity and higher argillaceous content, the intensity of the T₂ spectra also shows a trend of a great decrease in the hydrate formation process, which means that high-saturation gas hydrate can also be formed in the sample with higher argillaceous content. The changes in MRI of the sample in the process show that the formation and dissociation of methane hydrate can reshape the distribution of water in the pores.©2022 China Geology Editorial Office.  相似文献   

桂西堆积型铝土矿中三水铝石的成矿机理   总被引：6，自引：0，他引：6  

刘云华  毛晓冬  黄同兴 《地球科学与环境学报》2004,26(2):26-31

桂西堆积型铝土矿中红土矿物共生组合、矿物空间分布规律、产出特征、矿物的形成世代、化学成分、稀土元素和矿体内外的水质成分的研究结果表明，堆积型铝土矿中的三水铝石是由硬水铝石水解形成的，三水铝石的形成受到地下水溶液中Al^3 、[SiO4]^4-浓度及pH等多种因素的制约，经历了Al(OH)3的沉淀、固化、脱玻化、结晶几个阶段。在淋滤作用的早期，形成了高岭石；在淋滤作用较弱的位置，形成了次生石英。表明该类型铝土矿不仅是新类型矿床，其成因也是独特的，是正处于退化中的铝土矿。  相似文献