A new method for exploiting mine geothermal energy by using functional cemented paste backfill material for phase change heat storage: Design and experimental study. (October 2022)

• Record Type: Journal Article
• Authors: Liu, Hengfeng; Rodriguez-Dono, Alfonso; Zhang, Jixiong; Zhou, Nan; Wang, Yanjun; Sun, Qiang; Zhang, Luobin
• Is Part Of: Journal of energy storage. Volume 54(2022)
• Publication Date: 2022-10
• Subjects: F-CBM Functional cemented paste backfill material utilizing coal-based solid waste for phase change heat storage -- C-BSW Coal-based solid waste -- GE-COSM Geothermal-coal synergetic mining -- PCM Phase change material -- F-CBM TECH Functional cemented paste backfill mining technology -- GE-COSM TECH Geothermal-coal synergetic mining technology -- T-CBM Traditional cemented paste backfill material -- PSD Particle size distribution -- SEM Scanning electron microscopy -- EDS Energy dispersive spectrometry -- DSC Differential scanning calorimetry -- EG Expanded graphite -- F-PCM Form-stable phase change material -- MIP Mercury intrusion porosimetry -- TC Thermal conductivity -- SHC Specific heat capacity -- HSC Heat storage coefficient; Phase change material -- Waste valorization -- Geothermal-coal synergetic mining -- Latent heat storage -- Deep mines; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2022.105292
• Languages: English
• ISSNs: 2352-152X

Abstract

Abstract: The research on mine geothermal energy exploitation has attracted global interest for many years. This paper proposes an innovative new method for geothermal-coal synergetic mining (GE-COSM) to expand the valorization of coal-based solid waste (C-BSW), reduce the environmental damage caused by coal utilization, and achieve a low-carbon transformation of the energy structure. A functional cemented paste backfill material (F-CBM) utilizing C-BSW for phase change heat storage was invented through orthogonal testing. This study obtained the main factors influencing raw material proportions on F-CBM working properties. Moreover, the optimal ratio of F-CBM raw materials was determined. F-CBM prepared with the optimal ratio showed improved working properties: the thermal conductivity (TC) and specific heat capacity (SHC) were increased by 75.70 % and 111.90 %, respectively, and the highest latent heat value was 17.37 J/g. The F-CBM's strength loss mechanism was discussed in terms of its mesostructure. In addition, it is shown that the backfilling layer formed by F-CBM in the goaf act as a thermal insulation and a phase change heat storage layer. Finally, the mine design principles of GE-COSM at different stages are summarized. These findings provide a reference for the application of F-CBM in engineering practice, and lay the groundwork for exploiting the mine geothermal energy. Graphical abstract: Unlabelled Image Highlights: Proposed a phase change heat storage for geothermal–coal synergetic mining method. The main factors affecting the working properties of the F-CBM were identified. The aperture of F-CBM was concentrated in the more harmful pores at 810.84 nm. F-CBM prepared with the optimal ratio showed superior heat storage properties. F-CBM acted as thermal insulation and a phase change heat storage layer.