摘要
盐穴压气蓄能是当前利用风、光等可再生能源实现电网调峰的重要技术。然而,在电站的日循环注采工况下,盐穴内湿环境会呈现高频高幅振荡。当盐穴温度因采气而骤降时,相对湿度可接近100%,该条件下腔周盐岩将发生潮解,导致腔体的横向扩展,影响盐穴的稳定性与密闭性。将损伤盐岩置于压气蓄能工况对应的干湿循环中,统计其潮解量。利用表观形貌分析了盐岩表面潮解速率随偏应力水平的变化规律,并建立了两者的拟合关系。开发了针对FLAC3D软件的单元凋亡法,嵌入模拟盐穴长期变形的数值程序中,基于试验结果计算腔周盐岩网格单元的潮解量并适时使之凋亡,从而表征潮解对盐穴宏观可用性的影响。结果表明:在长期运行后,腔体轮廓会因围岩潮解而略微向外延伸,使得腔周位移与安全系数轻微恶化,但仍能充分满足经验性的安全判据。然而,潮解的盐将固定盐穴空气中的水分,转化为卤水汇集于腔体底部从而显著降低盐穴可用体积。这一影响远高于地层蠕变导致的腔体收缩,须通过增设地面除湿装置与定期排卤等措施予以控制。
Salt cavern compressed air energy storage(CAES)is currently an important technique for grid peak regulation using renewable energy sources such as wind and solar power.However,daily gas injection and withdrawal result in high-frequency and high-amplitude fluctuations in the wet environment within the salt cavern.When the cavern temperature drops during gas withdrawal,the relative humidity can reach nearly 100%,causing the surrounding rock salt to deliquesce,which leads to lateral expansion of the cavern and affects its stability and tightness.This study involved exposing damaged rock salt to dry-wet cycles that mimic CAES operation conditions,and measuring the amount of deliquescence.The variation of the deliquescent rate on the salt surface with the deviation stress level was analyzed using the visual morphology,and their fitting relationship was established.A cell apoptosis method for FLAC3D was developed,which was embedded in the numerical program simulating the long-term deformation of salt caverns.The subroutine calculates the deliquescent amount of the surrounding rock salt cells and induces their apoptosis at appropriate time,to characterize the macroscopic effect of deliquescence on the usability of salt caverns.The results show that after long-term operation,the cavern slightly extends outward due to the deliquescence of the surrounding rock,causing a slight deterioration in the displacements and the safety factor of the cavern wall,but still adequately satisfying the empirical safety criterion.However,deliquescent salt traps moisture in the air,which accumulates at the cavern bottom as brine,significantly reducing the cavern’s available volume.This change is more significant than creep shrinkage and requires control through the use of ground dehumidifiers and regular brine discharging.
作者
曾真
马洪岭
梁孝鹏
李航
王轩
李文韬
ZENG Zhen;MA Hong-ling;LIANG Xiao-peng;LI Hang;WANG Xuan;LI Wen-tao(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2024年第12期3510-3522,共13页
Rock and Soil Mechanics
基金
湖北省重点研发计划(No.2022BAA093,No.2022BAD163)
江西省重大科技研发专项(No.2023ACG01004)。
关键词
盐穴压气蓄能
盐岩
干湿循环
潮解
二次开发
salt cavern compressed air energy storage(CAES)
rock salt
dry-wet cycle
deliquescence
secondary development
