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The separate and explosion-proof materials (SEPM) is one of the effective means to suppress explosion. The suppression effects of three SEPM on C3H8 explosion were experimentally studied. Based on experiments, explosion product analysis, and numerical simulation, the explosion suppression mechanism was revealed. The experimental results show that the explosion pressure and explosion pressure rise rate significantly decreased after filling with SEPM. The order of explosion suppression upon is iron velvet > aluminum velvet≈mesh extended aluminum alloy (EA). The explosion products are quantitatively analyzed by gas chromatography. After filling with SEPM, the contents of CO and CO2 obviously reduced, and the contents and species of hydrocarbons increased, such as C3H4, i-·C4H10, n-·C4H10, and i-·C5H10. The reaction mechanism of i-·C5H10 was added to the reaction mechanism file of propane. The explosion reaction of propane is numerically simulated by Chemkin-Pro software. The reaction paths of propane forming various explosive products are obtained. Furthermore, the explosion suppression mechanism of SEPM is revealed from physical mechanism and chemical mechanism. It is obtained different SEPM suppress explosion in different ways. These studies are expected to develop a new separate and explosion-proof technology to find more suitable materials in essence. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) with excellent mechanical properties have broad application scope and application prospects. However, it is difficult to obtain the optimized element composition, based on the traditional equiatomic or near-equiatomic statistical analysis of the phase selection rules. The non-equiatomic HEAs have abundant constituents combination by optimizing the type and content of elements. In this study, Ni10Cr6WFe9TiAlx (x = 0, 1.0 and 1.5, at.%) HEAs were prepared by vacuum arc melting. The effect of Al content x on microstructure and mechanical properties of HEAs was systematically studied. The results show that the HEAs are composed mainly of face-centered cubic (FCC) with hexagonal Al2W phase. The increase of Al content promotes the formation of the hexagonal Al2W phase. When the Al mole content is 1.0, the Ni10Cr6WFe9TiAl HEA material has achieved superior mechanical properties. The alloy exhibited a high ultimate tensile strength of 741 MPa and a large total elongation of 46%. The improvement in the mechanical properties of the Ni10Cr6WFe9TiAl HEA is mainly attributed to the precipitation strengthening of the high-density Al2W phase. This work provides a reference for the future design of Al2W precipitation-strengthened non-equiatomic HEAs with ideal properties. [ABSTRACT FROM AUTHOR]

Blended coal combustion technology is being adopted by more and more power plants as a clean coal combustion technology, while the combustion of coal coke accounts for more than 85% of the total combustion process of pulverized coal. In order to investigate the effects of different factors on the pore structure and fractal properties of the blended coal coke, a low-temperature nitrogen adsorption method and scanning electron microscopy are used to study the coal coke consisting of three types of coal after pyrolysis. The adsorption isotherm analysis indicates that the pore structure in blended coal coke consisted mainly of semi-open pores with semi-cates. Petroleum coke can severely inhibit microporosity when the content of petroleum coke in the blended coal sample exceeds 10%. The microporosity distribution of blended coal coke with different blending ratios is more concentrated than that of mesopores. In addition, it is found that the trend of D1 is consistent with the trend of the ratio of the microporous specific surface area to the total specific surface area in the blended coal coke. Bituminous coal will make the blended coal coke have a complex structure and petroleum coke will make it have a smooth surface. [ABSTRACT FROM AUTHOR]

The effects of hydrogen with volume fraction of 1%, 2% and 4% on the key free radicals in methane explosion were studied by using the CHEMKIN-PRO software. The results show that the elementary reactions with the greatest influence of hydrogen on methane explosion are R38(H+O2⇒O+OH) and R84(OH+H2⇒H+H2O). After the addition of hydrogen, the production of CO2 decreased, the production of H2O increased, the sensitivity of R155 (CH3+O2⇒O+CH3) and R156(CH3+O2⇒OH+CH2O) decreased, and the reaction rates of · H, · O, · OH and other key free radicals increased, resulting in an increase in the intensity of methane explosion. The bigger the volume fraction of hydrogen added, the greater the promotion effect on methane explosion. [ABSTRACT FROM AUTHOR]

For an air staged combustion boiler, the rational organization of jets to form closing-to-wall film using as little air as possible plays a key role in resolving the high temperature corrosion problems. In this work, a comprehensive computational fluid dynamics (CFD) model including hydrodynamics and coal combustion is established for a 660 MW opposed wall fired boiler. Based on the grid independence and model validation, the flow field, temperature profile, and species concentration are predicted, and the influences of the structure of nozzles and the operation parameter of jets are further evaluated. The results show that the corrosion area of the side wall is dependent on the jet projection velocity and nozzle structures. The increase of the jet velocity does not always have an active influence on the reduction of corrosive area. Only increasing the nozzle diameter does not always have a positive impact on the improvement of the corrosion. The increase of the jet inclination angle can extend the jet trajectory, contributing to increase the oxygen coverage area. Reasonably adjusting the jet inclination angle of each layer can obtain the lower corrosion area. The increase of jet row number leads to a decrease in the spacing between rows, which enables the downstream jet to penetrate deeper into the cross stream. By increasing the number of jet layers and reducing the jet velocity of each layer, the lowest corrosion area can be obtained. [ABSTRACT FROM AUTHOR]