Gas explosion suppression performance of modified gel-type dry waters

In this paper, the gas explosion (methane-air mixture explosion) suppression properties of the gel and modified dry water powders were investigated using a transient flame propagation system. The results revealed that the moisturising ability of dry water powders containing gel or ammonium dihydrogen phosphate (the chemical formula is NH4H2PO4, and its abbreviation is MAP) has been improved. The optimal explosion suppression performance was achieved when the concentration of MAP in the aqueous solvent was 10% and the dry water concentration was 520 g/m3. In a 10 vol% gas explosion, the gellan gum gel dry water, calcium alginate gel dry water, 10 mass% MAP–modified dry water, 10 mass% MAP–modified gellan gum dry water, and 10 mass% MAP–modified calcium alginate dry water decreased the maximum flame propagation velocity by 17.50%, 20.63%, 25.62%, 26.76%, and 28.44%, respectively; decreased the maximum flame temperature (as measured at a point in the lower part of the pipeline) by 37.84%, 42.47%, 45.55%, 46.31%, and 53.71%, respectively; and decreased the maximum explosion venting pressure by 6.43%, 9.16%, 13.77%, 16.50%, 21.08%, and 36.70%, respectively. According to thermogravimetric analysis, the mass losses of the MAP-modified dry waters during pyrolysis were greater than those of the unmodified dry waters. Studies have revealed that MAP-modified calcium alginate dry water can effectively suppress explosions and has a stable particle structure. [Display omitted] •A method for preparing dry water powder with stable structure was obtained.•Composite gel modified dry water has superior explosion suppression effect.•Calcium alginate type 10% MAP modified dry water is the optimal inhibitor.•The inhibition mechanism is mainly endothermic and free radical adsorption.