Characterization of Thermal Stability and Heat Absorption for Suppressant Agent/Combustible Dust Mixtures via Thermogravimetric Analysis/Differential Scanning Calorimetry

Abstract

Combustible dusts continue to present a critical threat toward personnel and process equipment in a wide variety of bulk solids processing industries. The addition of noncombustible inert material to combustible dust mixtures, either through premixing or high-rate injection as the flame front begins to develop, is common practice for preventative inhibition or explosion protection via active suppression, respectively. Metal dusts in particular present an extremely reactive explosion risk due to amplified heat of combustion, burning temperature, flame speed, explosibility parameters (KSt and Pmax), and ignition sensitivity. Establishment of proper prevention and mitigation designs for metal fuel deflagrations has posed challenging. The aim of this paper is to propose a method for the characterization of the inhibition efficiency of five suppressant agents (sodium bicarbonate [SBC], potassium bicarbonate [PK], monoammonium phosphate [MAP], diammonium phosphate [DAP], and sodium chloride-based [Met-L-X]) when mixed with both organic (cornstarch) and metallic (zinc) fuels. For each 1:1 wt % fuel/agent mixture, thermal stability and heat absorption have been evaluated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC).