Effect of CaCl₂, Al(OH)₃ and NH₄H₂PO₄ and their dosages on the explosion intensity of pulverized coal

ABSTRACT

In this paper, the TGA-DSC curve of coal powder explosion inhibitors was analyzed. At the same time, the influence of the explosion inhibitor type and mass fraction on the five explosion intensity parameters of pulverized coal P_ex,(dp/dt)_ex,K_st,t₁, and t₂ was explored. The results show that CaCl₂ and NH₄H₂PO₄ go through three main stages: dehydration stage, decomposition stage and crystal transformation stage after high-temperature heating. Calcium chloride absorbs heat through the process of water volatilization and crystal transformation to prevent the combustion of pulverized coal. Meanwhile, NH₄H₂PO₄ absorbs heat through decomposition, evaporation and sublimation reactions to prevent the combustion of pulverized coal. For these two explosion inhibitors, the explosion intensity of pulverized coal decreases with the increase of mass fraction. The increase of Al(OH)₃ mass fraction basically does not enhance its explosion suppression effect. After adding NH₄H₂PO₄, the maximum decrease of P_ex was 32.08%, which was 11.89% and 16.99% higher compared to the addition of CaCl₂ and Al(OH)₃, respectively. The maximum decrease of (dp/dt)_ex was 98.47%, which was 29.45% and 33.38% higher compared to the addition of CaCl₂ and Al(OH)₃, respectively. Therefore, the order of explosion suppression performance was determined as: NH₄H₂PO₄ > CaCl₂ > Al(OH)_3.

KEYWORDS:

• Flame retardant
• explosion intensity
• dust explosion inhibitor
• explosion suppression performance
• TGA-DSC

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15567036.2022.2087802

Additional information

Funding

This work was supported by the Fundamental Research Funds for the Central Universities [2021YJSAQ18].