Suppression performance and mechanism of water mist containing compound potassium salts on hydrogen-enriched natural gas jet flame

Abstract

A non-premixed jet fire could be caused when a gaseous fuel leakage occurs during the storage and transport of hydrogen-enriched natural gas when the fuel is ignited in still air. Water mist systems exhibit limitations in fully addressing both the fire suppression efficiency challenges and environmental contamination concerns associated with hydrogen-enriched natural gas fires. Therefore, it is necessary to mitigate the risk of hydrogen-enriched natural gas leakage by using water mist containing potassium compound salt. Simulated experiments were designed and conducted to evaluate the suppression performance of water mist containing potassium compound salt. The diameter of the nozzle (3.15, 4.0, 4.94, 5.65, and 6.0 mm), the volume flow rates (10, 20, 30, 40, 50, and 60 L/min), and the spray pressure (0.2, 0.3, and 0.4 MPa) were the variables. The characteristic parameters of the water mist containing potassium compound salt were analyzed to evaluate the feasibility and effectiveness of water mist containing potassium compound salt. Combining the flow field of water mist containing potassium compound salt and hydrogen-enriched natural gas jet flame via PIV, the competitive behavior and quantitative relationship of the gas-spray interaction was revealed, analyzed, and elucidated. The results show that the nozzle has high fire extinguishing effectiveness under high spray pressure conditions. Furthermore, the flame height under spray pressure suppression was shown to decrease with the increase in spray pressure. To sum up, a prediction model for leakage gas suppression is proposed based upon the gas-spray momentum ratio. A simplified reaction kinetic mechanism containing gaseous KOH was constructed to elucidate the suppression mechanism of hydrogen-enriched natural gas jet flame by fine water mist containing potassium compound salt. The research results have vital reference value for optimizing water mist-containing additions systems to suppress gas leakage in such applications. The proposed model and mechanism can provide valuable information to develop more accurate and efficient combustion models, thus improving the safety and applicability of industrial processes.