Study on dissolution kinetics of rock salt in the construction of underground energy storage salt cavern

Abstract

Water solution mining is one of the ways to construct a salt cavern in rock salt formation. However, current research on the dissolution mechanism of rock salt is unclear. In this paper, the dissolution mechanism of rock salt is revealed and a kinetic model is established by a series of dissolution tests. Results show that ion diffusion is the control step of rock salt dissolution under static conditions, the surface reaction rate constant is 5 ∼ 6.4 times that of the ion diffusion rate constant. The temperature increases from 20 to 50 °C under static conditions, the dissolving rate of rock salt increases by 20 %. The convection of solution significantly promoted the dissolution of rock salt. When the stirring speed of rock salt increases from 0 to 600 rpm, the dissolving rate of rock salt can increase by 218 %. The average relative error of the predicted dissolving rate of rock salt is 13.14 %.