【作者】 刘贤信；

【导师】 郑津洋；

【作者基本信息】 浙江大学 ， 化工过程机械， 2012， 博士

【摘要】 氢能以其来源丰富、无污染、燃烧效率高、可再生等优点成为新世纪最具发展前景的二次能源。氢能可储存和输送,是能量密度低、难储存、稳定性差的可再生能源利用的重要桥梁,是人类战略能源的发展方向。经济、安全、可靠的储氢是氢能规模化利用的关键之一。高压储氢具有设备结构简单、压缩氢气制备能耗低、充放速度快等优点,是目前占绝对主导地位的储氢方式。高压储氢容器是高压储氢系统的关键设备。随着高压氢系统从应用示范向工业应用转变进程的加快,对高压储氢的规模和安全性的要求将越来越高,与之相适应高压储氢容器将继续朝着大容积、高压力、高可靠性的方向发展,随之而来的大容积高压储氢容器结构强度优化设计和金属材料高压氢脆问题,也将越来越突出。在国家高技术研究发展计划(“863计划”)项目“高压容器储氢技术和装备”(项目编号：2006AA05Z143)和“70MPa高压氢气储存加注系统关键技术及装置研究”(项目编号：2009AA05Z118)的支持下,针对浙江大学发明的大容积全多层高压储氢容器结构,本文围绕容器筒体等强度优化设计、封头与筒体连接结构强度、容器安全性及氢在金属中的富集特性等关键问题开展研究,完成的主要工作有：(1)基于带宽方向有效正应力和切应力模型,推导出考虑钢带层间摩擦力的缠绕预应力及工作状态下应力分析方法,完善和发展了钢带错绕筒体弹性应力分析方法,在此基础上,建立了一种基于逆向递推思想的钢带缠绕预拉应力计算方法,开发了大容积全多层高压储氢容器优化设计软件(登记号为：2011SR060577),并以自主研制的75MPa、2.5m3大容积全多层高压储氢容器为例,将本文建立的钢带缠绕预拉应力确定方法与前人提出的低应力内筒法及未考虑摩擦力的等切应力缠绕法进行比较,本文建立的方法既实现了钢带层沿壁厚方向的等强度,又将内筒应力控制在较低的水平,具有显著的优点。(2)以自主研制的75MPa、2.5m3高压储氢容器为对象,开展了大容积全多层高压储氢容器封头和筒体连接结构强度试验研究,获得了加强箍、封头及其连接部位应力随内压的变化情况。建立了精度较高的大容积全多层高压储氢容器封头和筒体连接结构弹塑性有限元分析模型。基于该模型,对封头和筒体连接结构在容器超压过程中的变形特征,及封头与加强箍配合面形成裂纹尖端在多次加载时的稳定性进行了分析,验证了加强箍结构经验设计方法的合理性。(3)从介质、设备、环境、操作与管理等方面,对大容积全多层高压储氢容器可能面临的风险进行了辨识,并提出了相应的风险控制措施。结合大容积全多层高压储氢容器自身的结构特点,从设计要点、实践基础和标准制定等方面对保障容器安全性的措施进行了分析。利用大容积全多层高压储氢容器封头和筒体均为多层结构的特点及其“只漏不爆”的失效特性,开发了容器泄漏监控系统,实现了容器安全状态的远程实时监测。(4)基于弹塑性断裂力学理论和广义扩散定律,建立了局部应力场作用下氢在金属中扩散行为的顺序耦合分析模型。基于该模型,揭示了裂纹尖端应力应变场、温度和材料界面等因素对氢的扩散行为与富集特性的影响规律,并在此基础上提出了防止氢在局部富集的措施。更多还原

【Abstract】 Hydrogen for its advantages of non-polluting, high combustion efficiency and renewable, has become the most promising secondary energy of the new century. Hydrogen can be obtained from other renewable energies which are of low energy density or poor stability, or difficult to store, therefore bridge up the gap for these energies’ direct usage.Economic, safe and reliable hydrogen storage is one of the key technologies for hydrogen industrialization. High pressure gaseous hydrogen storage, primarily for its technical simplicity and fast filling-releasing rate, has become the most popular and mature method. High pressure hydrogen storage vessel is the key for high pressure hydrogen storage system.The process for hydrogen changing from demonstration to industrialization is speeding up day by day. And high pressure storage vessels with larger volume, higher pressure and reliability are needed. Therefore, more and more attention should be paid on the issues such as optimal design of large volume high pressure hydrogen storage vessel and high pressure hydrogen embrittlement of metal.This research is supported by the National High Technology Research and Development Program of China (863Program)"Technology and equipment of high pressure hydrogen storage vessels"(No.2006AA05Z143) and "Key technology and equipment for70MPa high-pressure hydrogen storage and refueling system"(No.2009AA05Z118). For large volume layered high-pressure hydrogen vessels, problems such as the optimal design of the cylinder, the strength of the joint structure for head and reinforce ring, safety of the vessel and hydrogen accumulation characteristic in metal, are studied in this thesis. The main contents and conclusions are as follows:(1) Based on the effective normal stress in the ribbon wide direction and shear stress model, an elastic stress analysis method is developed in which the friction between ribbon layers are fully considered. Then, a calculation method for the pre-tension stress of the ribbon is established based on reverse recursive thinking, and the optimum design software (Registration No:2011SR060577) for large volume layered high-pressure hydrogen vessels is developed. Taken the self-developed hydrogen storage vessel with the design pressure of75MPa and the volume of2.5m3for example, compared with other methods, the pre-tension stress calculation method established in this thesis can fulfill equal strength along the vessel’s thickness direction, and at the same time keeps the inner shell with low-stress level, therefore with obvious advantage.(2) Experimental study has been taken on the strength of the joint structure for the vessel’s head and reinforce ring which is of the design pressure of75MPa and the volume of2.5m3. And the stress distribution around the area of the head, reinforce ring and their joint is obtained from experimental study. A finite element analysis model was established to study the deformation characteristics of the joint structures for the head and reinforce ring. Based on this model, the deformation characteristics of the joint structures for the cylinder and the head during over-pressure process, and the stability of the crack tips which is formed by the weld between the head and reinforce ring during cyclic loading process is studied. The results showed that the joint structures is of enough strength, so the empirical design method is fit for the reinforce ring’s design.(3) Various hazardous factors are indentified systematically through five aspects-medium, equipment, environment, operation and management, and some risk control policies are put forward accordingly. Considering the structural characteristics of the large volume layered high-pressure hydrogen vessels, the safety of the vessel is analyzed from the viewpoint of the key points of the design, the experience in the use and the development of standard. Based on the unique multi-layered structure characteristics and failure characteristics which is only leak but never burst, the leakage monitoring system is developed which can realize real time remote monitoring of the vessel’s safety status.(4) Based on the elastic-plastic fracture mechanics theory and the general law of diffusion, a sequentially coupled mass diffusion analysis method for hydrogen diffusion in metals under local stress fields has been established, and the influence of stress intensity factor, material interface and temperature on hydrogen diffusion and accumulation behaviors has been studied by this numerical analysis method. The mechanism of hydrogen accumulation at the interface of different materials has been revealed. And the reason why hydrogen will not accumulated at the interface of clad steel plate during working conditions has been analyzed. On the basis of above results, measures to prevent hydrogen accumulation in local areas have been proposed.更多还原