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In an effort to control dust pollution in open-air environments such as pit coal mines and coal transportation systems, a new dust suppressant with a cross-linked network structure was prepared. Graft copolymerization of soy protein isolate (SPI) and methacrylic acid (MAA), using potassium persulfate (KPS) as the initiator and hexametaphosphoric acid (SHMP) as the cross-linking agent, formed the network structure. The optimal MAA/SPI mass ratio for the dust suppressant was determined through a single-factor experiment to be 3:4, with 0.8 and 0.2 g of SHMP and KPS, respectively. The grafting reaction required 30 min at 60 °C. Scanning electron microscopy, energy-dispersive x-ray spectroscopy, Fourier-transform infrared spectroscopy, and differential scanning calorimetry were used to characterize the structure and application performance of the dust suppressant. The experimental results showed that the graft copolymerization reaction successfully formed the desired cross-linked network, and that when the cross-linked network material was sprayed on coal dust, it formed a dense, solidified shell, which effectively resisted wind erosion and served as a dust suppressant. The average reduction of the total suspended particulate matter of an open-air coal pile reached 79.95%, demonstrating effective dust suppression. [ABSTRACT FROM AUTHOR]

The polyethylene (PE) industry is in a stage of rapid development. However, PE dust floating in the air is frequently associated with unexpected explosions. To find a proper way of preventing and mitigating the potential of PE dust explosion, a study was carried out in which (NH 4) 2 CO 3 and SiC were used for the first time to suppress PE deflagration flames. In a Hartmann tube apparatus, PE deflagration flame propagation in the presence of (NH 4) 2 CO 3 and SiC powders as the suppressant was observed. The suppression effects of these two powders at different mass fractions were compared. The results showed that flame propagation velocity and acceleration decrease with increasing mass fraction of (NH 4) 2 CO 3 and SiC. Through XRD, FIRT, TG-DSC, GC–MS and sensitivity test, explosion products and combustion reactions were characterized and the PE explosion suppression mechanisms of (NH 4) 2 CO 3 and SiC for PE were compared and investigated. PE explosion is suppressed by SiC physically by reducing temperature and pressure of explosion combustion, while the explosion combustion of PE was suppressed by physical and chemical effect of (NH 4) 2 CO 3. As a result, (NH 4) 2 CO 3 is better able to suppress explosion flames. The study provides a theoretical and practical basis for the prevention and control of explosion fire accidents in the polyethylene industry. [Display omitted] • (NH 4) 2 CO 3 and SiC were used for the first time to suppress PE deflagration flames • The advantages of synergistic inhibition were illustrated by comparative study • The inhibition mechanism of PE deflagration for two novel inhibitors was revealed [ABSTRACT FROM AUTHOR]

[Display omitted] The properties of a green waste molecular sieve-based powder suppressor in inhibiting the flame propagation of coal dust were studied. Waste molecular sieve (S) was pretreated and selected as the carrier, potassium oxalate (K) and ferric citrate (T) as the active components. The reverse dissolution crystallization method was adopted and S@K/T, S@T/K, S@ T -K suppressors with different core–shell structure were prepared by different loading sequences. Their particle size, morphology and thermal pyrolysis behavior were compared. The results showed that the particle distribution of three powders is uniform and the dispersity of them is good. The active components of explosion suppression are evenly loaded on the waste molecular sieve carrier and they have different coating structure. The thermal desorption heat of them is 44.64 J/ g, 66.95 J/g and 92.9 J/g, respectively. Furthermore, the flame propagation characteristics of coal dust were tested by the Hartmann flame propagation device. The results showed that all powders had the effect of inhibiting the flame propagation of coal dust and the inhibition effect is S@ T -K, S@T/K and S@K/T from strong to weak. Combined with characterization results, the influence mechanism of the difference in the flame propagation inhibition effect of three suppressants was investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] To explore ways of further guaranteeing the production safety of coal processing, novel powder suppressors with core–shell structure were prepared through anti-solvent crystallization method by loading potassium oxalate (K) and ferric citrate (T) on treated waste molecular sieve. Flame propagation experiments were performed to investigate the effects of suppressors prepared under different conditions on coal dust flame propagation. The results showed that when K and T were added simultaneously at the loading of 30 wt%, the suppressor S@T-K showed best suppression performance. The pyrolysis-oxidation mechanism of coal dust with and without suppressor S@T-K was analyzed using Coats-Redfern (C-R) method. After the suppressor was added, the activation energy increased by 11.55 kJ/mol and 15.37 kJ/mol in the rapid and slow pyrolysis stages, respectively. The activation energy values of the coal sample with and without the suppressor under different conversion ratios were further calculated using Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods. The average activation energy values during the rapid and slow pyrolysis stages both agree well with the C-R calculation, which verifies the appropriateness of using C-R method to identify the reaction mechanism. By combining the coal dust flame propagation behaviors with the pre- and post-explosion characterization results, it is proposed that waste molecular sieve composite powders with core–shell structure suppress flame propagation through the synergy of physical and chemical reactions. [ABSTRACT FROM AUTHOR]