Electrical charge loss during pyrolysis of single coal particles

Westerholt and Ibbenburen coal particles were devolatilized by means of a l aser using an electrodynamic balance. The devolatilization occurred at ambi ent pressure and in a pure nitrogen atmosphere. The heating rate was modera te below 100 K/s. The particle temperature and the balancing voltage (to ke ep a single particle in the center of the balance) were measured continuous ly. Particle size and shape, and the aerodynamic drag force were measured b efore and after the reaction. Charge loss of the reacted particle was deter mined and it was found to be proportional to weight loss, indicating that a t least a fraction of the evolved devolatilization products can carry charg e which seems only to be possible for high molecular weight products such a s a condensed phase. (C) 1999 Elsevier Science Ltd. All rights reserved.