Effect of nucleating agents on fire prevention of dry ice from compound inert gas

Abstract

To effectively mitigate hazards caused by mine fires and enhance the antifire effects of inert gas, herein, an antifire technology of dry ice made from compound inert gas is proposed and the preparation effect and firefighting performance of dry ice under the influence of different nucleating agents and their mass are studied. Results showed that adding a nucleating agent could reduce the cold source required for CO2 condensation and increase the CO2 conversion rate. Calcium chloride possessed the strongest ability to promote dry ice nucleation, and the mass of dry ice generated was proportional to the mass of the added nucleating agent (below 640 g). When a 640-g nucleating agent was added, the tube temperature approached a minimum value (153 K), accompanied by the optimal nucleation effect of CO2. After injecting the compound inert gas slurry with calcium chloride into a loose coal body, the temperature at each measuring point in the box continued to decrease; the low-temperature area was conical, the coal temperature increased slowly after the injection was stopped, and the temperature in the box was low at the end of the return temperature. The aforementioned technology has an excellent effect on coal cooling and reheating.