| 高压水热体系CH4电化学传感器的研制 | |
| 唐镜淞 | |
| Thesis Advisor | 徐丽萍 |
| 2014 | |
| Degree Grantor | 中国科学院研究生院 |
| Place of Conferral | 北京 |
| Degree Name | 硕士 |
| Degree Discipline | 地球化学 |
| Keyword | Ch4传感器 水热体系 高温高压 Ysz 电势型传感器 |
| Abstract | 随着陆地油气资源的日渐枯竭，各国都将目光聚焦到海洋资源的开发上，海洋油气资源尤其是天然气水合物资源将是未来世界油气资源勘探和开发的重点。天然气水合物中，CH4的储量巨大，是已探明的煤、石油、天然气总和的两倍。对于天然气水合物的研究在当前世界范围内还主要处于勘探阶段。目前，许多国家都在使用地震探测、海底热流探查、海底地质取样、地热方法等勘探手段对天然气水合物进行勘探，但是对于与天然气水合物形成相关的海底火山和热液喷口处的CH4来源则很少进行探测，更未见使用化学传感器原位探测此高温高压环境中CH4逸度/活度的报道。因此，本论文研制的可用于海底火山口和热液喷口处CH4直接探测的化学传感器补充了国际上现有的天然气水合物勘探方法，且对探明天然气水合物的分布具有非常重要的指导意义。 本论文研究将高温、常压、非水环境下固体电解质基CH4等烃类电化学传感器的测量原理引入高压水热体系，自行设计并制作了可用于高压水热体系中CH4逸度/活度原位测量的固体电解质基电势型传感器。该传感器由高压釜（模拟高温高压水热环境）、高压釜釜塞（传感器元件承载装置）、YSZ圆台（YSZ，钇稳定氧化锆固体电解质）、Al2O3圆台（含轴向贯通的两根Pt丝，用于将信号由高温高压水热体系引出至常温常压环境）、Pt电极（活性电极）、Au电极（惰性电极）以及Pt引线等组成。 使用注浆成型法加工制作了YSZ陶瓷和Al2O3陶瓷圆柱体，并利用课题组拥有的磨床、金刚石切片机等将陶瓷圆柱体进一步加工成传感器的主要部件YSZ圆台和Al2O3圆台。使用浆料烧结法在YSZ圆台表面上分别烧制互相不连通的半圆形活性电极Pt电极与惰性电极Au电极，在Al2O3圆台表面上烧制两互相不连通的半圆形Pt电极。上述传感器元件制作完毕后，将各元件按一定次序组装并接入数据测试系统，测试不同温度条件下传感器对不同浓度CH4的电势响应信号。 采用课题组研制的高压釜装置模拟高温高压水热环境。在通入CH4气之前对传感器系统强度、密封性以及电导通进行了测试。设定实验温度为500 oC，压力为500 bar。结果表明该传感器具有一定强度、信号传输稳定且密封性较好，满足实验要求。 使体系在300和400 oC不同温度条件下恒温，并分别向水热体系内通入1、3、5、7 bar的CH4气体，考察体系温度和CH4浓度对传感器响应信号值的影响。实验结果表明：传感器对CH4的响应信号值随着CH4浓度的增大而增加，且在考察的CH4浓度范围内，响应信号值与CH4浓度呈线性关系，说明传感器在300和400 oC恒温时对CH4浓度变化具有良好的响应能力。传感器在400 oC恒温时的响应信号值比在300 oC恒温时的响应信号值要高，亦即传感器的响应信号值随温度的升高而增大。 使体系在300、330、360、400和450 oC条件下恒温，并分别向水热体系内通入3 bar的CH4气体，考察不同温度下，传感器对体系内相同CH4气体浓度变化的响应速率快慢。实验结果显示：传感器的响应速率随着温度的升高而加快，且传感器在400 oC以上时响应非常快速。 |
| Other Abstract | As the dwindling of the oil and natural gas resources on land, countries in the world will focus on development of the marine resources. Marine oil and gas resources, especially the natural gas hydrate will be the key point for exploration and development of the world’s oil and gas resources in the future. Natural gas hydrate contains huge reserves of CH4, which is twice the sum of the proven coal, oil and gas reserves. It is mainly in the stage of exploration for the research of the natural gas hydrate in the current world. At present, many countries are using seismic exploration, submarine heat flow measurements, seafloor soil sampling and geothermal method for the exploration of the natural gas hydrate, but rarely using them for the detection of the thermogenic CH4 gas, which forms the natural gas hydrate in submarine volcano and hydrothermal vents. As for the chemical sensor for in situ measurement of CH4 fugacity/activity in submarine volcano and hydrothermal vents has not been reported. Therefore, it is a very important guiding significance for ascertaining the distribution of gas hydrate by developing a kind of chemical sensor for in situ measurement of CH4 in submarine volcano and hydrothermal vents, which supplies the existing detection methods internationally. The theory of the solid electrolyte based electrochemical sensors for the detection of CH4 or other hydrocarbon gases in high temperature and normal pressure non-hydrothermal system is introduced in high temperature hydrothermal system. Then solid electrolyte based potentiometric sensor is developed for in situ measurement of CH4 fugacity/activity in high pressure hydrothermal system in this experiment. The sensor is made up of various components, including an autoclave (modeling temperature and pressure environment in submarine volcano and hydrothermal vents), an autoclave plug (sensor’s elements bearing device), YSZ frustum of a cone (YSZ, solid electrolyte yttria stabilized zirconia), Al2O3 frustum of a cone (two Pt wires axially interpenetrating the Al2O3 aiming at leading potential signal from high temperature and high pressure hydrothermal system to normal temperature and normal pressure environment), Pt electrode (active electrode), Au electrode (inert electrode), and Pt wire. YSZ and Al2O3 ceramic cylinders are prepared by slip casting method，and then are processed from cylinders into YSZ and Al2O3 frustum of cones of the major parts of sensor by grinding machine and diamond cutting machine in our research group. Paste sintering techniques are used to fire the semicircle Pt active electrode and semicircle Au inert electrode respectively on the top surface of the YSZ frustum of a cone ensuring so that the two electrodes are not contacted with each other. As for the Al2O3 frustum of a cone, two semicircle Pt electrodes are fired on it separately. After completing the above components of the senor, the elements are assembled in a certain order into the data testing system. Under the condition of different temperature, the potential response signals of sensor to different concentrations are tested. An autoclave manufactured by our group is used for modeling high temperature and high pressure hydrothermal environment. Before piping the CH4 gas into the system, the strength, gas-tight, and conducting of the signal of the sensor system are tested. The experiment temperature and pressure is set at 500 oC and 500 bar, results show that the sensor has certain strength, stable signal transmission and good sealing property, which satisfies the requirement of experiment. The experiment temperature is sustained at 300 and 400 oC, and then 1, 3, 5, 7 bar CH4 are piped into the hydrothermal system respectively to research on the influence of the system temperature and the CH4 concentrations on sensor response signal values. The experiment results indicate that the response signal values of CH4 sensor increase with the growth of CH4 concentrations, and within the invest |
| Subject Area | 地球深部物质与流体作用地球化学 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.gyig.ac.cn/handle/352002/5911 |
| Collection | 研究生_研究生_学位论文 |
| Recommended Citation GB/T 7714 | 唐镜淞. 高压水热体系CH4电化学传感器的研制[D]. 北京. 中国科学院研究生院,2014. |
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