Thermophysical characterization of mustard husk (MSH) and MSH char synthesized by the microwave pyrolysis of MSH

Abstract Thermophysical properties are calculated to determine performance parameters comprising specific heat capacity, thermal conductivity, thermal diffusivity and they are directly related to the dynamics of the material at atomic level and for thermal treatment of mustard husk (MSH) and MSH char, they play a vital role. Temperature dependence of thermophysical properties of MSH and MSH char have been investigated within the temperature range between 30 and 110 °C. MSH char is synthesized by the microwave pyrolysis of MSH. Thermogravimetric analysis of MSH and MSH char confirmed that MSH is more thermally stable as compared to MSH char. Moreover, it gave information about the degradation behaviour of MSH and MSH char. Thermophysical properties are measured by thermal analyser, based on the transient hot wire technique which is suitable to measure the thermal conductivity at elevated temperatures. At room temperature, thermal conductivity and thermal diffusivity of MSH are 0.187 W m−1 K−1 and 0.132 mm2 s−1, respectively. Specific heat capacity of MSH and MSH char are found to be almost same (1.349 kJ kg−1 K−1 for MSH and 1.310 kJ kg−1 K−1 for MSH char). Thermal conductivity and thermal diffusivity values are decreasing on increasing the temperature while specific heat capacity is increasing linearly on increasing the temperature. Low thermal conductivity and thermal diffusivity values of MSH imply that the conventional conductive heating is less effective and inefficient for the thermal treatment of MSH.