Inspiration from a thermosensitive biomass gel: A novel method to improving the stability of core-shell “dry water” fire extinguishing agent

Dry Water as a Promoter for Gas Hydrate Formation: A Review

Applications of clathrate hydrate require fast formation kinetics of it, which is the long-standing technological bottleneck due to mass transfer and heat transfer limitations. Although several methods, such as surfactants and mechanical stirring, have been employed to accelerate gas hydrate formation, the problems they bring are not negligible. Recently, a new water-in-air dispersion stabilized by hydrophobic nanosilica, dry water, has been used as an effective promoter for hydrate formation. In this review, we summarize the preparation procedure of dry water and factors affecting the physical properties of dry water dispersion. The effect of dry water dispersion on gas hydrate formation is discussed from the thermodynamic and kinetic points of view. Dry water dispersion shifts the gas hydrate phase boundary to milder conditions. Dry water increases the gas hydrate formation rate and improves gas storage capacity by enhancing water-guest gas contact. The performance comparison and synergy of dry water with other common hydrate promoters are also summarized. The self-preservation effect of dry water hydrate was investigated. Despite the prominent effect of dry water in promoting gas hydrate formation, its reusability problem still remains to be solved. We present and compare several methods to improve its reusability. Finally, we propose knowledge gaps in dry water hydrate research and future research directions.

Insight to hydrophobic SiO2 encapsulated SiO2 gel: Preparation and application in fire extinguishing

Micron-sized hydrophobic SiO₂ encapsulated SiO₂ gel (HSESG) was prepared successfully by using SiO₂ gel as the solid core and hydrophobic nano-SiO₂ particle as the shell under high-speed shear stirring. The flowability, stability, particle size distribution, bulk density and water repellency of the powder were measured separately, and it was concluded that this type of product can exhibit smaller static angle, larger flow rate and lower bulk density. After the formation of a stable spatial network of SiO₂ gel in its interior, relevant fire extinguishing experiments were carried out and HSESG exhibits higher efficiency in suppressing wood stack fires than that of ordinary dry water (DW) and ABC dry powder. As a high-efficiency fire-extinguishing material, it also exhibits excellent environmental friendliness and non-toxicity, which will make it have the potential to develop a new application market.