Method and device for building underground storehouse by dissolving limestone with carbon dioxide

Abstract

A method for building an underground storehouse by dissolving limestone with carbon dioxide, the method comprising the following steps: a.) drilling two wells extending from the ground surface () to a limestone layer (), building a channel () allowing the two wells to communicate, and installing casing pipes () respectively in the two wells; b.) introducing COgas having at least 1 MPa of pressure into a COabsorbing solution having the same pressure to form a COsolution, flowing the COsolution into underground via the casing pipe () to react with the limestone to form a calcium bicarbonate solution, forming a cavern in the meanwhile, and discharging the calcium bicarbonate solution via the other casing pipe (); c.) decompressing the discharged calcium bicarbonate solution to decompose the calcium bicarbonate contained in the solution into CO, water and calcium carbonate, and recycling the separated COabsorption solution and the CO; repeating steps b.) and c.) until a cavern meeting design requirements is formed, and discharging the solution from the cavern to form the underground storehouse (). Also disclosed is a device for building an underground storehouse by dissolving limestone with carbon dioxide, the device comprising a COstorage tank (), an absorption tower (), a crystallizer (), a pressure relief valve (), a gas-liquid separator (), a vacuum pump (), a buffer () and booster pumps ().