Zero-Emission Water Cycle When Developing Underground Gas Storage in Rock Salt Formation

Abstract

Abstract The aim of the work is the possibility of creating a closed water cycle during the development of underground gas storages in rock salt formations with obtaining commercial sodium chloride. Desalination experiments were carried out on standardized test solutions with various concentrations of sodium chloride (1%, 5%, and 10% solutions NaCl). Desalination was executed on a pilot electrodialysis unit, as this process has a higher degree of concentration than reverse osmosis. The dissolution rates of formation (NaCl) were determined under conditions of salt formation washing-out. Optimal concentrations of brine were defined experimentally. The possible salt rejection is determined. It is possible to direct the concentrate to the evaporation unit and obtain commercial salt - sodium chloride. Experiments have shown that it is possible to desalinate brine obtained by formation washing-out and reuse the desalted permeate. This reduces operational costs, as to obtain commercial product it is required smaller volume of evaporation unit. It also helps to reduce consumption of fresh water needed to salt formation washing-out. The flowsheet of the water cycle during the development of underground gas storages in salt formations with obtaining a commercial product at the output has been developed.