A novel nano-grade organosilicon polymer:Improving airtightness of compressed air energy storage in hard rock formations

Enhancing cavern sealing is crucial for improving the efficiency of compressed air energy storage(CAES)in hard rock formations.This study introduced a novel approach using a nano-grade organosilicon polymer(NOSP)as a sealant,coupled with an air seepage evaluation model that incorporates Knudsen diffusion.Moreover,the initial coating application methods were outlined,and the advantages of using NOSP compared to other sealing materials,particularly regarding cost and construction techniques,were also examined and discussed.Experimental results indicated a significant reduction in permeability of rock specimens coated with a 7–10μm thick NOSP layer.Specifically,under a 0.5 MPa pulse pressure,the permeability decreased to less than 1 n D,and under a 4 MPa pulse pressure,it ranged between4.5×10^(-6)–5.5×10^(-6)m D,marking a 75%–80%decrease in granite permeability.The sealing efficacy of NOSP surpasses concrete and is comparable to rubber materials.The optimal viscosity for application lies between 95 and 105 KU,and the coating thickness should ideally range from 7 to 10μm,applied to substrates with less than 3%porosity.This study provides new insights into air transport and sealing mechanisms at the pore level,proposing NOSP as a cost-effective and simplified solution for CAES applications.

Gas leakage mechanism in bedded salt rock storage cavern considering damaged interface

During the long-time operation of salt rock storage cavern,between its formations,damaged interfaces induced by discontinuous creep deformations between adjacent layers will possibly lead to serious gas leakage.In this paper,damaged interfaces are considered as main potential leakage path:firstly in meso-level,gas flow rule along the interface is analyzed and the calculation of equivalent permeability is discussed.Then based on porous media seepage theory,gas leakage simulation model including salt rock,cavity interlayers and interface is built.With this strategy,it is possible to overcome the disadvantage of simulation burden with porous-fractured double medium.It also can provide the details of gas flowing along the damaged zones.Finally this proposal is applied to the salt cavern in Qianjian mines(East China).Under different operation pressures,gas distributions around two adjacent cavities are simulated;the evolvement of gas in the interlayers and salt rock is compared.From the results it is demonstrated that the domain of creep damage area has great influence on leakage range.And also the leakage in the interface will accelerate the development of leakage in salt rock.It is concluded that compared with observations,this new strategy provides closer answers.The simulation result proves its validity for the design and reasonable control of operating pressure and tightness evaluation of group bedded salt rock storage caverns.