Influence of Gas Injection Pipe on CO2 Decomposition by CaCl2-CaO Molten Salt and ZrO2 Solid Electrolysis

The electrochemical decomposition of carbon dioxide to form carbon and oxygen gas was studied in CaCl2-CaO molten salt. The water model experiment was carried out to study on the influence of the tip shape of the pipe, the pipe diameter and wettability to the gas injection pipe for the bubble shape in molten salt. Bubbles were formed in both conditions of horizontal and oblique tip with good wettability of the gas injection pipe. The specific surface area of bubble using oblique tip of the pipe was smaller than horizontal tip. On the other hand, slug flows appeared with poor wettability. In the hot mode experiment, the current density was measured, and the carbon dioxide gas concentration decreased. The carbons were detected from the sample after the experiment. The decrease of carbon dioxide gas concentration using oblique tip were more remarkable than the case using horizontal tip with the same pipe. It is likely that the form of carbon dioxide gases in the molten salt were bubbles shape.