Electrical charge loss during pyrolysis of single coal particles

Westerholt and Ibbenbüren coal particles were devolatilized by means of a laser using an electrodynamic balance. The devolatilization occurred at ambient pressure and in a pure nitrogen atmosphere. The heating rate was moderate below 100 K/s. The particle temperature and the balancing voltage (to keep a single particle in the center of the balance) were measured continuously. Particle size and shape, and the aerodynamic drag force were measured before and after the reaction. Charge loss of the reacted particle was determined and it was found to be proportional to weight loss, indicating that at least a fraction of the evolved devolatilization products can carry charge which seems only to be possible for high molecular weight products such as a condensed phase