Role of active components in composite dry water materials for suppressing hydrogen-blended natural gas explosions: An experimental investigation and discussion of plausible suppression mechanisms

Hydrogen blending can significantly alter the explosion behavior of natural gas and increase safety concerns. In this study, the explosion characteristics of hydrogen-blended natural gas and the suppression performance of composite dry water (DW) materials were investigated using a 20 L spherical explosion vessel. Mixtures with hydrogen blending ratios of 0–30% and equivalence ratios of 0.8, 1.0, and 1.2 were tested to obtain the explosion pressure, pressure rise rate, and flame propagation behavior. Based on the explosion-pressure results, the 30% H 2 mixture at φ = 1.0, which exhibited a relatively high maximum explosion pressure, was selected to evaluate the suppression effects of potassium bicarbonate (KHCO 3 ), potassium chloride (KCl), ammonium polyphosphate (APP), and monoammonium phosphate (MAP) dry water. The results show that increasing the hydrogen fraction increases the maximum explosion pressure, maximum pressure rise rate, and flame propagation intensity, with the most severe explosion occurring near φ = 1.0. Under the tested condition of 30% H 2 and φ = 1.0, KCl dry water at 150 g/m 3 reduced the maximum pressure rise rate from 12.8 MPa/s without suppressant to 2.6 MPa/s, corresponding to a 79.7% reduction. Flame development exhibited a non-monotonic response at relatively low dry-water concentrations and was generally delayed as the concentration increased. The observed suppression behavior may result from the combined effects of evaporative cooling, dilution, flame disturbance, and plausible interactions with radical-related reaction processes. These findings provide guidance for explosion mitigation in hydrogen blended natural gas systems.