RESUMEN
Coking coal is a precious resource in the world and an important raw material for the production of steel, but it is easy to cause explosion accidents in the process of coking coal mining, which is very detrimental to safe production. In order to reveal the influencing factors of coking coal dust explosion intensity and the suppression effect of inert dust on coking coal dust explosion, an experimental study was carried out in this paper. The results show that the particle size and the mass concentration of coal dust have a great influence on the explosion pressure and flame. By analyzing the suppression effects of NaCl, KCl, and NH4H2PO4 on coking coal dust explosion, it is got that NH4H2PO4 has the best explosion suppression effect. When the mass percentage of NH4H2PO4 mixed into coking coal dust increases to 60%, the maximum explosion pressure decreases by 0.47 MPa, and the maximum flame length decreases by 0.50 m. As the particle size of NH4H2PO4 decreases, the explosion intensity continue to decrease. When the particle size of NH4H2PO4 is 0 ~ 25 µm, and the mass percentage of NH4H2PO4 mixed into coking coal dust is 50%, the explosion doesn't occur anymore.
RESUMEN
Coal is an important strategic resource in the world; coal production safety has always been widely concerned. In coal mine production, inert dust can effectively reduce coal dust explosion accidents in mine tunnels. To reveal the suppression effect of inert dust on lignite dust explosion, CaCO3, SiO2, and NH4H2PO4 are selected for suppression experiments. It is found that the lignite dust explosion pressure decreases continuously as the mass percentages of inert dust mixed into lignite dust increase. By calculating the molar mass, the suppression effects of CaCO3 and SiO2 on lignite dust explosion are compared. The lignite dust no longer explodes when the mass percentage of NH4H2PO4 dust mixed into lignite dust is 70%, indicating that NH4H2PO4 is more effective than that of CaCO3 and SiO2. The smaller the particle size of NH4H2PO4, the better the suppression effect on explosion. The lignite dust does not explode when the mass percentage of NH4H2PO4 is 60% and the particle size of NH4H2PO4 is 25-38 µm, which proves that decreasing the particle size of NH4H2PO4 is important to suppress explosion. The research results are of great significance for grasping the explosion suppression effect of inert dust on lignite dust.
RESUMEN
Bismuth halide perovskites have recently been considered a potential alternative to lead halide analogues due to their low toxicity and high stability. However, the layered flake structure and wide band gap limit their applications in perovskite solar cells (PSCs). We herein show that large-grained all-inorganic bismuth-based perovskites with a narrow band gap can be obtained from a Lewis acid-base adduct reaction under ambient conditions. Thiourea (CH4N2S) is utilized as a Lewis base to interact with BiI3, confirmed with infrared (IR) spectra. The strong coordination between thiourea and the Bi3+ center could slow down the perovskite crystallization and promote the preferred orientation of the perovskite crystals with a hexagonal phase. The morphology of the perovskite films varies dramatically with an increase of molar ratio of BiI3 and thiourea in the precursor. The perovskites derived from a BiI3/thiourea ratio of 1:2 display extrathick grains, higher surface coverage, extended light absorption, higher crystallinity, and similar air stability compared to the pristine sample. The power conversion efficiency (PCE) of the thiourea-induced bismuth perovskite solar cells is significantly enhanced due to the higher surface coverage and the broader absorption of the perovskite film.