An experimental and modeling study of heating rate and particle size effects in bituminous coal pyrolysis

Heating rate (10-20 000 K/s) and particle size (63-75 μm at 1073 K; 106-125 μm at 1073 and 1273 K) effects on tar yields and total weight loss from pyrolysis of Pittsburgh No. 8 bituminous coal in an electrical screen heater were measured under 1 atm of helium. Tar molecular weight distributions and gravity column elution behavior were also determined. With increasing heating rate, weight loss increased for both particle sizes. For the 106-125-μm particles, tar yield plateaued or maximized at about 1000-2000 K/s. Tar yields at 1073 K were similar for both particle sizes at 10 K/s, but larger for the 63-75 μm particles at all other heating rates