Specific heat and thermal conductivity of softwood bark and softwood char particles

Very few data exist regarding the thermal properties of softwood bark and therein derived softwood chars. This work describes the measurement of specific heat and particle thermal conductivity of softwood (SW), softwood bark (SB) and therein derived softwood char (SC). Differential scanning calorimetery (DSC) was used to measure the specific heat. At 313 K, the measured specific heat was found to be 1172, 1364 and 768 J kg⁻¹ K⁻¹ for SW, SB and SC, respectively. The specific heat of SW and SB increased linearly from 1172 to 1726 and 1364 to 1777 J kg⁻¹ K⁻¹, respectively, with an increase in temperature from 313 to 413 K. With an increase in temperature from 313 to 713 K, the specific heat of SC doubled from 768 to 1506 J kg⁻¹ K⁻¹ and followed a polynomial relationship with temperature. A modified Fitch apparatus was constructed, calibrated and used for measurement of particle conductivity of SW, SB and SC. The particle thermal conductivity of SB was found to be twice that of SC, i.e. 0.2050 and 0.0946 W m⁻¹ K⁻¹, respectively, at 310 K. The particle thermal conductivity of SW, SB and SC followed a linear increase with temperature.