Comparative analysis of thermodynamic and mechanical responses between underground hydrogen storage and compressed air energy storage in lined rock caverns

Underground hydrogen storage(UHS)and compressed air energy storage(CAES)are two viable largescale energy storage technologies for mitigating the intermittency of wind and solar power.Therefore,it is meaningful to compare the properties of hydrogen and air with typical thermodynamic storage processes.This study employs a multi-physical coupling model to compare the operations of CAES and UHS,integrating gas thermodynamics within caverns,thermal conduction,and mechanical deformation around rock caverns.Gas thermodynamic responses are validated using additional simulations and the field test data.Temperature and pressure variations of air and hydrogen within rock caverns exhibit similarities under both adiabatic and diabatic simulation modes.Hydrogen reaches higher temperature and pressure following gas charging stage compared to air,and the ideal gas assumption may lead to overestimation of gas temperature and pressure.Unlike steel lining of CAES,the sealing layer(fibre-reinforced plastic FRP)in UHS is prone to deformation but can effectively mitigates stress in the sealing layer.In CAES,the first principal stress on the surface of the sealing layer and concrete lining is tensile stress,whereas UHS exhibits compressive stress in the same areas.Our present research can provide references for the selection of energy storage methods.

A preliminary site selection system for underground hydrogen storage in salt caverns and its application in Pingdingshan,China

Large‐scale underground hydrogen storage(UHS)provides a promising method for increasing the role of hydrogen in the process of carbon neutrality and energy transition.Of all the existing storage deposits,salt caverns are recognized as ideal sites for pure hydrogen storage.Evaluation and optimization of site selection for hydrogen storage facilities in salt caverns have become significant issues.In this article,the software CiteSpace is used to analyze and filter hot topics in published research.Based on a detailed classification and analysis,a“four‐factor”model for the site selection of salt cavern hydrogen storage is proposed,encompassing the dynamic demands of hydrogen energy,geological,hydrological,and ground factors of salt mines.Subsequently,20 basic indicators for comprehensive suitability grading of the target site were screened using the analytic hierarchy process and expert survey methods were adopted,which provided a preliminary site selection system for salt cavern hydrogen storage.Ultimately,the developed system was applied for the evaluation of salt cavern hydrogen storage sites in the salt mines of Pingdingshan City,Henan Province,thereby confirming its rationality and effectiveness.This research provides a feasible method and theoretical basis for the site selection of UHS in salt caverns in China.

Rock mass response for lined rock caverns subjected to high internal gas pressure

The storage of hydrogen gas in underground lined rock caverns(LRCs)enables the implementation of the first fossil-free steelmaking process to meet the large demand for crude steel.Predicting the response of rock mass is important to ensure that gas leakage due to rupture of the steel lining does not occur.Analytical and numerical models can be used to estimate the rock mass response to high internal pressure;however,the fitness of these models under different in situ stress conditions and cavern shapes has not been studied.In this paper,the suitability of analytical and numerical models to estimate the maximum cavern wall tangential strain under high internal pressure is studied.The analytical model is derived in detail and finite element(FE)models considering both two-dimensional(2D)and three-dimensional(3D)geometries are presented.These models are verified with field measurements from the LRC in Skallen,southwestern Sweden.The analytical model is inexpensive to implement and gives good results for isotropic in situ stress conditions and large cavern heights.For the case of anisotropic horizontal in situ stresses,as the conditions in Skallen,the 3D FE model is the best approach.

Spalling failure of deep hard rock caverns

Spalling is a typical brittle failure phenomenon of hard rock in deep caverns under high geostress.In this study,key issues are systematically studied concerning the spalling failure of deep hard rock caverns.First,the prismatic rock specimens with small thicknesses(i.e.width×thickness×height:20 mm×50 mm×100 mm)are employed in our tests which not only successfully simulate the spalling failure of hard rock in the laboratory but also obtain a reasonable spalling strength similar to that of the rock mass.Then,a series of spalling experiments is carried out to investigate the mechanism of spalling failure of deep hard rock caverns.Our results show that the intermediate principal stress,weak dynamic disturbances,and rock microstructure have significant effects on the spalling failure.The spalling strength is approximately(0.3–0.8)UCS,where UCS is the uniaxial compressive strength of the cylindrical rock sample with a diameter of around 50 mm.The spalling strength increases first and then decreases with increasing intermediate principal stress.Moreover,an empirical spalling strength criterion and a numerical method of spalling failure are proposed.This numerical method can not only simulate the spalling failure zone formed by tangential compressive stress concentration after excavation under different intermediate principal stresses,but also successfully simulate the failure transition from tensile mode to shear mode associated with confinement change in deep hard rock caverns.Furthermore,an acoustic emission-based early warning method using neural network is proposed to predict the spalling failure.Finally,a technical roadmap for preventing and controlling spalling failure of deep hard rock caverns is presented after summarizing the successful experiences in a typical engineering case.

Effect of rock joints on lined rock caverns subjected to high internal gaspressure

The storage of hydrogen gas in lined rock caverns(LRCs)may enable the implementation of the firstlarge-scale fossil-free steelmaking process in Sweden,but filling such storage causes joints in the rockmass to open,concentrating strains in the lining.The structural interaction between the LRC componentsmust be able to reduce the strain concentration in the sealing steel lining;however,this interaction iscomplex and difficult to predict with analytical methods.In this paper,the strain concentration in LRCsfrom the opening of rock joints is studied using finite element(FE)analyses,where the large-and small-scale deformation behaviors of the LRC are coupled.The model also includes concrete crack initiation anddevelopment with increasing gas pressure and rock joint width.The interaction between the jointed rockmass and the reinforced concrete,the sliding layer,and the steel lining is demonstrated.The results showthat the rock mass quality and the spacing of the rock joints have the greatest influence on the straindistributions in the steel lining.The largest effect of rock joints on the maximum strains in the steellining was observed for geological conditions of“good”quality rock masses.

Determination of convergence of underground gas storage caverns using non-invasive methodology based on land surface subsidence measurement

Undergroundgas storage caverns aremonitoredfor environmental safety in termsof equipmentandpotential emissions,particularly methane emissions from the underground and above-ground parts of the storage facility.Periodical measurements of land surface deformations and costly echometric measurements of convergence of individual storage facilities are carried out.The aims of environmental monitoring are:(1)to eliminate potential hazards in the shortest time,(2)assess the overall impact of intensive operation of storage facilities on the environment,(3)developmonitoringmethods relevant to environmental protection,and(4)take actions in case of failure.The paper presents a solution to the problem of determination of the convergence of underground caverns in a salt rock mass based on the results of land surface subsidence measurements carried out using the Gauss-Markov equalization algorithm.Themethod makes it possible for ongoing control of cavern volume convergence after each subsidence measurement on the ground surface and determining the actual impact of the use frequency(injection-mediumconsumption)on the convergence in time.The presentedmethodology is universal and verified on caverns located in a salt rockmass.The Gauss-Markov inversion model is the first used in this area,hence its application is significant.

压气储能地下储气库衬砌裂缝分布特征及演化规律研究

地下储气库衬砌的主要作用是将内压传递给围岩,且同时作为柔性密封层的附着基层。高内压作用下衬砌开裂可导致密封层出现反射型裂缝,进而引起高压气体的泄漏。为深入认识地下储气库衬砌的开裂特征,开发了基于FLAC3D平台的衬砌裂缝分析程序,研究了衬砌配筋方式、配筋率、钢筋保护层厚度、围岩类别和温压循环荷载作用等因素对衬砌开裂演化特征的影响。研究成果表明:对衬砌采取合理的配筋方式和改善围岩质量的措施可有效控制衬砌裂缝的宽度;采用分区配筋的方式可有效控制圆形断面隧洞式储气库衬砌中的最大裂缝宽度,同时降低衬砌的配筋量。空气压力和温度同步变化引起的热力耦合效应还有助于减小衬砌中出现的裂缝宽度。

新能源用钢管的应用现状、需求分析及思考

“双碳”战略下新能源及相关产业发展给钢管带来新的应用场景,对钢管的功能和性能提出新的需求。聚焦于碳捕获、利用与封存技术领域中的CO_(2)输送用管、氢能领域中的氢气输送用管和储能领域中的盐穴压缩空气储能用注采管,总结了新能源用钢管的应用现状和研究进展,分析了各领域用管需求,并就“双碳”背景下新能源用钢管的基础理论研究、关键技术开发和标准体系建设等方面进行了思考,提出了建议。

我国盐穴资源评价及调查技术研究

在“双碳”目标大背景下,盐穴是实现地质储能、碳封存的重要方式之一,但我国盐穴资源数量、质量不明,盐穴调查技术体系不完善,严重制约盐穴资源开发利用。通过分析我国主要盐矿区地质勘探报告、储量核实报告、企业年报及文献报道等,形成了我国盐穴资源数量、可利用性的科学认识和基本判断;在盐穴集中区开展综合探测技术试验并结合前人试验成果,初步构建了盐穴资源调查技术体系。结果表明:(1)我国盐穴资源丰富,储量大、分布广、埋深适宜、具备规模化开发利用条件,其中华东和华中地区已有盐穴资源最为丰富。(2)通过建立盐穴资源可利用性评价体系,将全国盐穴资源分为Ⅰ、Ⅱ、Ⅲ3级,Ⅰ级已有盐穴资源占比约29.4%,主要分布在华东、华中地区的江苏、湖北、河南等省份,是开发利用的优选区;Ⅱ级已有盐穴资源占比约65.4%,广泛分布于华中、西北和西南地区,可作为开发利用远景区;Ⅲ级已有盐穴资源占比约5.2%,整体地质条件不适宜开发利用。(3)地面物探可查明盐矿区区域地质、盐层地质、水文地质及盐腔分布情况,指导盐穴建库选址;井中物探精度高,可获取盐矿品味、腔体结构等信息,服务储库建设及运行监测。研究结果可为我国盐穴资源规划及开发提供基础数据和技术支撑。

中国大规模盐穴储氢需求与挑战

氢能是来源广泛且低碳清洁的能源,大力发展氢能产业是实现双碳目标和应对全球能源转型的重要举措。在氢能“制备―储存―运输―应用”全产业链中,储氢难问题长期制约着氢能产业高质量发展。盐穴储氢具有成本低、规模大、安全性高和储氢纯度高等突出优势,是未来氢能大规模储备的重要发展方向,也是我国能源低碳转型的重大战略需求。综合调研了我国制氢产业和氢能消费现状,分析了我国盐穴储氢的需求。调研了国外利用盐穴储存天然气和氢气的技术及工程现状,总结了我国盐穴储气库发展和建设历程。对比了利用盐穴储存天然气、氦气、压缩空气和氢气的异同点,提出我国盐穴储氢面临三大科技挑战:层状盐岩氢气渗透与生化反应、盐穴储氢库井筒完整性管控、储氢库群灾变孕育与防控。研究成果明确了我国氢气储备需求的快速增长趋势和大规模盐穴储氢的重点攻关方向。

DWI联合3D动脉自旋标记技术对鞍旁脑膜瘤与海绵状血管瘤的鉴别诊断价值

目的:探讨DWI联合3D-ASL技术在鞍旁脑膜瘤与海绵状血管瘤的鉴别诊断价值。方法:回顾性分析经手术病理证实的鞍旁脑膜瘤与海绵状血管瘤各20例的MRI资料,分析平扫、增强扫描、DWI、3D-ASL图像特点,并测量最小ADC值及最大相对脑血流量(rCBF)。结果:鞍旁脑膜瘤多呈类圆形,T_(2)WI多呈等信号,增强扫描以早期中等程度强化常见,常见瘤周水肿及脑膜尾征;DWI多呈等高信号,最小ADC值(0.67~1.12)×10^(-3)mm^(2)/s,平均(0.76±0.13)×10^(-3)mm^(2)/s;多呈中高灌注,rCBF为5.072~9.683,平均7.062±3.571。海绵状血管瘤多呈哑铃状,T_(2)WI多呈高信号,增强扫描以充填式显著强化为主,未见瘤周水肿及脑膜尾征;DWI多呈低信号,最小ADC值(1.48~1.83)×10^(-3)mm^(2)/s,平均(1.56±0.25)×10^(-3)mm^(2)/s;多呈低灌注,rCBF为1.356~3.014,平均1.696±1.028。2组肿瘤形态、T_(2)WI信号、DWI信号、最小ADC值、强化方式、灌注信号及rCBF的差异均有统计学意义(均P<0.05)。结论:DWI联合3D-ASL技术在鞍旁脑膜瘤与海绵状血管瘤的鉴别诊断中具有较高的应用价值。

压缩空气储能电站浅埋人工储气洞库设计基本理念和方法

抽水蓄能和新型储能是实现碳达峰碳中和,支撑以新能源为主体新型电力系统的重要技术和基础装备。压缩空气储能(compressed air energy storage, CAES)是一种利用压缩空气作为介质来储存能量和发电的技术,是目前除抽水蓄能以外规模最大的物理储能方式,而硬岩浅埋型人工储气洞库选址灵活,具有规模化、商业化的发展潜力。面对我国大中型压缩空气储能电站开发建设形势和要求,结合国内外相关研究和工程实践经验,本文提出了硬岩条件下浅埋人工储气洞库整体稳定、局部稳定、循环稳定和密封层稳定的工程设计基本理念,总结提炼了洞库选址及地质勘探要求、埋深设计、储气库布置、结构设计、密封系统设计等方法,为压缩空气储能电站浅埋人工储气洞库设计提供借鉴和参考。

基于ISM-SD的地下洞室群施工进度风险传递路径研究

针对水电工程地下洞室群施工进度风险存在传递问题,提出了基于解释结构模型(ISM)和系统动力学(SD)的地下洞室群施工进度风险传递路径分析方法。根据地下洞室群的施工特点,建立了地下洞室群施工进度风险指标体系;结合风险传递机理,运用解释结构模型分析风险因素间传递关系,建立了风险因素传递矩阵,并总结归纳出风险因素关系对照表,通过系统动力学分析风险因素间传递路径,揭示了施工进度风险传递路径网络;集成ISM-SD构建了地下洞室群施工进度风险传递路径分析模型,并结合西南地区某大型水电站地下洞室群工程进行分析。结果表明,该方法可有效识别施工进度风险重要因素和关键传递路径,为地下洞室群施工进度风险管理提供了决策依据。

妊娠合并颅内海绵状血管瘤15例临床分析

目的分析妊娠合并颅内海绵状血管瘤(cerebral cavernous malformation,CCM)的临床特征及妊娠结局,探讨妊娠合并CCM患者的围生期管理。方法回顾性分析2015年8月~2022年8月首都医科大学宣武医院诊治的15例妊娠合并CCM患者的病理资料。结果15例患者共经历16次妊娠,均于孕前发现CCM。初始临床表现癫痫5例,突发头痛4例,因头痛发现脑出血1例,一过性晕厥1例,共济失调1例,无临床症状3例;以癫痫为临床表现的病例中,4例患者孕前手术或放疗后癫痫发作减轻或消失,1例孕前未治疗者孕期癫痫发作频繁,给予药物加量后未再发作;无孕期手术治疗者,无新发脑出血病例;孕足月阴道分娩3例,剖宫产11例,孕18周引产1例;产后突发癫痫持续状态1例,其余母儿健康。结论妊娠合并CCM需要多学科团队(multi-disciplinary team,MDT)共同管理,妊娠可能增加癫痫发作风险;孕前应至神经外科行风险评估,孕期适时调整抗癫痫药物,分娩后仍要严密监测。分娩方式的选择需要产科、神经科、麻醉科及母胎医学组成的MDT团队共同讨论评估后决定。

地下洞室变形破坏物理模拟的力学相似畸变映射原理与实例分析

相似物理模拟是研究地下工程变形破坏问题的重要手段,然而经典相似理论关于相似模型与工程原型之间的几何相似比和材料力学参数相似比的相互约束,导致室内物理相似模型尺寸和材料力学参数一直面临难以完全满足相似准则的困局,从而产生力学畸变和模拟试验结果解译困难。为此,提出了地下洞室变形破坏物理模拟的力学相似畸变映射处理方法,引进畸变系数和映射系数,通过耦合解析法或数值法来映射畸变效应,实现地下洞室物理模拟结果对原型力学行为的定量解译;以圆形隧洞为工程原型,采用水泥基3D打印隧洞物理模型进行相似物理超载试验,基于提出的耦合力学相似畸变法与解析法对物理模拟结果进行了定量分析和对比验证;以某水电站地下洞室群为研究原型,通过砂岩3D打印洞室群物理模型的超载试验获得洞室破坏的变形值,采用耦合力学相似畸变法与数值方法对物理模拟结果进行定量分析。实例分析结果表明,在物理相似模拟中几何相似比和力学相似比不满足经典相似准则条件下,该方法可实现圆形隧洞或复杂洞室群原型的相似物理模拟结果的定量映射分析,对非恒定相似比的地下洞室物理模拟畸变分析具有普适性。

复杂系统视角下洞室施工人员安全认知仿真研究

为制定有效的安全认知提升策略及减少安全事故的发生,需深入探究洞室施工人员安全认知的演化过程和特征。首先,基于复杂社会技术系统和“2-4”模型(24Model)等相关知识,识别安全认知影响因素,构建洞室施工人员安全认知指标体系;然后,通过Super Decisions软件计算指标权重;随后利用系统动力学(SD)理论,明确各因素间的相互关系,建立包含组织安全管理等4个子系统的SD仿真模型,将以安全投入为基础的认知纠偏机制应用到SD仿真模型;最后,结合实际工程算例开展SD仿真以及敏感性分析。研究表明:随着工程进展,通过增加安全投入,并发挥认知纠偏机制作用,施工人员的整体安全认知由下降趋势转变为缓慢上升趋势;组织安全管理对洞室施工人员安全认知影响程度最大,结果与24Model的基本假设一致,从而验证了SD仿真模型的科学性和有效性。

马陵山站硐室改造前后VS型垂直摆倾斜仪数据质量分析

利用潮汐分析法,分析和评价了马陵山站VS型垂直摆倾斜仪硐室改造前后数据质量的变化情况,结果表明:(1)历年数据观测精度m_γ均小于0.02,仪器搬迁至改造后硐室又有显著提升,数据质量优于搬迁前,超越全国形变优秀台的标准;(2)搬迁后仪器观测噪声水平M_l始终在0.005″左右,稳定性更好;(3)校正后发现搬迁前仪器安装方位角存在较大偏差,影响M_(2)波相位滞后。硐室环境优化改造是有效改善观测数据精度,提高数据质量的重要保证。

基于多影响因素联合的某抽水蓄能电站主厂房洞室围岩变形预测

为保证地下洞室围岩环境的安全状态,提出了一种以变分模态分解(VMD)方法分解原始数据和粒子群优化算法(PSO)提高预测精度为基础,基于多影响因素联合核极限学习机(KELM)方法的洞室围岩变形预测方法。该方法首先采用VMD方法将监测位移分解为受趋势性因素影响的趋势项位移和受周期性因素影响的周期项位移,去除影响因素的干扰项,其次将演化状态及影响因素作为PSO-KELM的输入数据,预测各影响因素所对应的趋势项或周期项位移,最后叠加两种分项位移,并将多影响因素结合的KELM方法与其他预测方法进行精度比较。对某抽水蓄能电站工程实测数据的验证结果表明,预测结果与原始位移的RRMSE相差仅0.76%,且二者的R为0.986,所提预测方法具有较高的预测精度,可为同类工程的围岩变形预测提供参考。

基于U型盐穴储气库的新型CCUS方法

我国江苏、广东等东部地区碳排放量高、碳减排压力大,且缺少适用于大型碳减排的油气藏地质构造,但存在丰富的盐矿资源,以及多年采盐形成大量盐穴老腔。在双碳目标严峻形势下,如何将这些盐腔利用起来实现碳减排具有重要的研究意义。文章基于U型盐穴储气库的特点提出了一种新型CCUS方法,并进行了碳封存量和垫底气替代量计算。结果表明,1对井组可封存二氧化碳8.2万t,天然气垫底气可降低3766×10^(4)m^(3),具有较好的经济效益和社会效益。

压缩空气储能地下储气库热力学改进模型研究

【目的】明晰地下储气库的热力学过程是压缩空气储能(compressed air energy storage,CAES)电站安全设计与运行调度的重要基础。【方法】现有地下储气库热力学模型在计算热量交换时,存在高压储气阶段热损失偏大和低压储气库阶段补热过多的不足。本文在全面分析地下储气库热力学模型理论基础合理性的前提下,先分析储气库热量计算偏差的形成根源;再提出改进模型。【结果】研究结果表明:现有的热力学计算解析模型忽略了CAES地下储气库在运行过程中温度分布的不均匀性,这种温度分布的不均匀导致储气室洞壁与压缩空气之间的对流换热模型失真,导致温度计算结果偏差大。考虑混合对流换热的改进模型二可以较好地解决储气阶段温度计算结果与真实结果之间偏差过大的问题。算例分析证明了改进模型二的合理性。【结论】本文的改进模型二可为CAES地下储气库容积优化设计与效率分析提供计算依据。