“双碳”目标下煤田区地热资源开发利用与储能技术

Geothermal energy exploitation and storage in coal field under the dual carbon goal

开发煤田地热不仅可以改善煤田开采的温度环境,还可以通过地热能的清洁利用变“害”为“利”,尤其是在目前“双碳”目标下利用煤田采空区储能大有前景。评估获得我国主要赋煤区地热资源热储量为1.12×10^(19) kJ,折合标煤3795.39亿t,可采热储量1.71×10^(18) kJ,折合标煤569.31亿t。其中,华北赋煤区的可采热储量约占74.7%,特别西区(晋陕蒙宁分区)拥有神东、晋北、晋东、晋中、陕北、黄陇(华亭)、宁东7大煤炭基地,资源最为丰富,占近48.7%。进一步指出“煤−热共采”是煤田区地热开发利用的主要形式,包括充填埋管取热、采空区矿井水取热和深部煤矿含水层取热等。此外,提出将采空区以及排水后腾出来的空间作为“储层”加以利用是下一步的工作方向,并对回填(相变)材料储热、废弃煤田抽水蓄能和废弃煤田压缩空气蓄能做了详细评述。最后,对煤田热害防治技术进行了简要评述。总之,煤田规模化储能与热害防治和地热利用将成为煤田地热研究和开发利用的主要方向,是实现煤矿绿色转型和国家“双碳”目标的重要抓手。

The development of geothermal energy in coalfield can not only improve the temperature environment of coal mining,but also turn waste into treasure through the clean utilization of geothermal energy.Especially,it is of great prospect to store energy in the mined-out area of coalfield under the“dual carbon”goal at present.Herein,in this paper,it was estimated that the geothermal reserves in the main coal-bearing areas of China were 1.12×10^(19) kJ,equivalent to 379.539 billion tons of standard coal,and the recoverable geothermal reserves were 1.71×10^(18) kJ,equivalent to 56.931 billion tons of standard coal.Among them,the recoverable geothermal reserves of the coal-bearing area in North China account for about 74.7%,especially in the western area(Jin‒Shaan‒Meng‒Ning sub-region),where seven coal bases were distributed,including Shendong,Jinbei,Jindong,Jinzhong,Shaanbei,Huanglong(Huating)and Ningdong,with the richest coal resources,accounting for nearly 48.7%.It was further pointed out that the“synergetic mining of coal and geothermal energy”would be the main form of geothermal development and utilization in coalfield areas,which included three methods of heat extraction,such as pipe filling and burying,mine water in coal mine goaf and deep coal mine aquifers.In addition,it was proposed to utilize the coal mine goaf and the space freed up after drainage as the“geothermal reservoirs”,which should be taken as the direction of working in the next step.Besides,a detailed review was presented regarding the heat storage with backfill(phase-change)material,pumped storage with abandoned coalfield and energy storage with compressed air in the abandoned coalfield.Last but not least,a brief introduction was presented for the thermal disaster prevention and control technology of coal mine.In conclusion,the scaled coalfield energy storage,thermal disaster prevention and control,and geothermal utilization will be the main directions of coalfield geothermal research,development and utilization.Which is also an important channel to achieve the green transformation of coal mines and the national"dual carbon"goal.