Evaluation of development potential of pumped hydroelectric storage and geothermal utilization system in abandoned coal mine

废弃矿井抽水蓄能与地热利用系统开发潜力评估

Every year in China,a significant number of mines are closed or abandoned.The pumped hydroelectric storage(PHS)and geothermal utilization are vital means to efficiently repurpose resources in abandoned mine.In this work,the development potentials of the PHS and geothermal utilization systems were evaluated.Considering the geological conditions and meteorological data available of Jiahe abandoned mine,a simple evaluation model for PHS and geothermal utilization was established.The average efficiency of the PHS system exceeds 70%and the regulatable energy of a unit volume is over 1.53 kW·h/m^(3).The PHS system achieves optimal performance when the wind/solar power ratio reaches 0.6 and 0.3 in daily and year scale,respectively.In the geothermal utilization system,the outlet temperature and heat production are significantly affected by the injection flow rate.The heat production performance is more stable at lower rate flow,and the proportion of heat production is higher in the initial stage at greater flow rate.As the operating time increases,the proportion of heat production gradually decreases.The cyclic heat storage status has obvious advantages in heat generation and cooling.Furthermore,the energy-saving and emission reduction benefits of PHS and geothermal utilization systems were calculated.

随着我国煤炭在一次能源消费结构中的比例逐年下降,关停矿井数量逐年增多,然而矿井直接关停或废弃会造成巨大的资源浪费,还有可能诱发安全、环境等问题。矿井地下具有丰富的水、热及空间资源,使得建立地下抽水蓄能(PHS)和地热利用系统成为废弃矿井开发再利用的重要手段。本文以徐州夹河废弃煤矿为案例背景,根据当地气象数据和煤矿地质条件,建立了PHS和地热利用系统的评估模型,评估了夹河煤矿抽水蓄能和地热利用系统的开发潜力。结果表明PHS系统的平均效率超过70%,单位体积可调节能量超过1.53 k W·h/m^(3)。当风能/太阳能占比分别达到0.6和0.3时,PHS系统在日和年尺度上达到最佳性能。在地热利用系统中,出水温度和产热量受开采流量的影响显著。在较小的开采流量下,产热性能较为稳定,而在较大开采流量的初始阶段,产热效率较高。随着运行时间的增加,产热效率逐渐降低。循环储热模式在供热、制冷和可持续开发等方面均具有明显的优势。此外,本文以上述评估结果为依据,计算了PHS和地热利用系统的节能减排效益。