Estimation of Thermal and Kinetic Parameters of Sugarcane Bagasse and Cotton Stalks Dust Layers from Hot Surface Ignition Tests

摘要

A method to estimate thermal and kinetic parameters of sugarcane bagasse and cotton stalks subject to thermal runaway is presented using the standard and modified ASTM E2021 hot surface ignition test apparatus. These parameters include thermal conductivity (k), activation energy (E), and coupled term (QA). Experimental tests are used to determine the minimum hot surface temperature for dust ignition, ignition temperature of the dust itself, and ignition times. Four different dust layer thicknesses: 6.4 mm, 12.7 mm, 19.1 mm, and 25.4 mm, are tested for each material and their E and (QA) values are calculated by a widely known multiple test method. The average value of estimated k is 0.08 W/m. K and 0.068 W/m. K for sugarcane bagasse and cotton stalks, respectively. For sugarcane bagasse, the activation energy ranges from 178.7 kJ/mol to 181.3 kJ/mol and the corresponding value of (QA) is 3.5 x 10(6) for this range. For cotton stalks, the activation energy ranges from 147 kJ/mol to 149.8 kJ/mol and the corresponding value of (QA) is 10 x 10(5) for this range. Results also showed that as the dust layer thickness increases, the minimum hot plate ignition temperature (T-min) decreases and the ignition time (t(ign)) increases. Different photographs for ignition of dusts are presented and discussed. Gas emissions during ignition are measured and discussed.