压气储能洞室气密性影响因素分析

Analysis of Influence Factors on Air Tightness of Underground Cavern for Compressed Air Energy Storage

压缩空气储能技术可以解决可再生能源发电的不稳定性和间歇性的缺点,而地下储气洞室是压气储能工程的重要组成部分.人工开挖并施作内衬的硬岩洞室因受地质条件限制小、适应范围广、气密性和稳定性好而受到关注.研究了内衬混凝土渗透率对洞室气密性的影响,基于达西定律,推导了计算储气洞室气体泄漏量的理论公式,获得了典型压缩空气储能压力条件下洞室内部气体的泄漏情况,并在此基础上分析了衬砌渗透率、衬砌厚度和洞室形状三种因素对气密性的影响.结果表明,在洞室内压8 MPa的情况下,利用P8等级的抗渗混凝土作为混凝土内衬,可以使洞室内气体日泄漏量低于1%,满足压缩空气储能电站的运行要求.同时,气体泄漏量随着内衬渗透率的增加而线性增加;在相同的渗透率条件下气体泄漏量随衬砌厚度的增加而减小;在相同容积条件下,圆柱形地下储气库的密封效果好于球形洞室.研究结果证明内衬硬岩洞室作为压缩空气的地下储气库在理论上具有良好的可行性.

Renewable energy resources are usually intermittent and instable. Compressed air energy storage （CAES） provides a good solution to this problem. Underground air storage cavern is an important part of CAES. Artificially-excavated hard rock cavern attracts wide attention for its little restriction to geology and wide adaptability. The influence of concrete lining permeability on air tightness ofunderground cavern was investigated. Based on the Darcy＇s law, analytical formulas for calculating the amount of air leakage within underground cavern were derived. Using the derived formulas, air leakage condition under a typical CAES operation pressure was analyzed. Furthermore, some influence factors, including lining permeability, lining thickness and cavern shape, were also analyzed. The results show that, when the inner pressure is 8 MPa and impervious concrete of P8 level is used as lining, air leakage rate will be less than 1%, meeting the operational requirements of compressed air energy storage power station. Air leakage will increase linearly with the increase of lining permeability. Compared with spherical cavern, cylindrical cavern has a better leakage-proof effect.