Thermo-physical properties of coal under transient conditions

Abstract Coal samples were obtained along the vertical axis in an eight-inch diameter experimental moving bed coal gasifier. This system had a throughput of half a tonne of sized (6 × 20 mm) coal per day. The specific heat and thermal conductivity were measured using the line heat-source method with a transient sample temperature. The coal sample was heated at a rate of 4 K/min during the property measurement. The heat capacity and thermal conductivity were obtained from an iterative fit of the experimental data to the heat conduction equation taking due account of the probe size and contact resistance. The apparatus was tested with samples of known properties such as alumina powder and glass micro-beads. The measurements reported here cover the range from 300–700 K. Effects of surface moisture and pyrolysis reactions can be identified. The results are compared with data in the literature measured at constant sample temperatures. The line source technique is well suited to transient property measurements.