Effects of particle size on the desorption kinetics of water from Beulah-Zap lignite coal: Differential scanning calorimetry results

The drying kinetics of water from three particle-sized Beulah-Zap lignite coal samples were probed using the differential scanning calorimetry technique at 295 < T < 480 K. The measurements undertaken under flowing N{sub 2} gas environment indicate that water is lost from this coal by two independent but simultaneously operative kinetic mechanisms. Our results suggest that the unimolecular decay kinetics are obeyed by those water molecules which are near the mouths of large pores and/or surround the coal particles. Most of the water, about 80% of the water lost in our experiments, was removed via a 2nd-order diffusion mechanism. As expected, the desorption activation energies of the 2nd-order diffusion kinetics were much larger than the decay mechanism`s activation energies. Our results also suggest, at least for particle sizes < 841 {mu}m, < 106 {mu}m, and < 37 {mu}m, that the coal particle size has little effect on the desorption activation barriers

A perspective on the status of coal research from shipments of samples

Research on all aspects of coal research, at least for more small scale work, involves the use of samples at the beginning of experimental work. Most research workers for smaller scale work do not collect their own coal samples, but rather order them from a group of sample suppliers. The number of suppliers meeting the major needs in the US, as well as for the world, is not very large. An examination of the shipments of samples from each of these suppliers will give an interesting insight into the general trends in volume of work in the field. The suppliers involved in this study include the Argonne Premium Coal Sample Program, the Illinois Basin Coal Sample Program, the SBN and the several groups of samples from the Pennsylvania State University Coal Sample Bank. Each of these supplies a different number of samples in varying quantities. The quantities and variety of samples is important to the individual worker in selecting a supplier. The type of work to be done frequently affects the quantities and choice of sample, which in turn affects the choice of supplier. In general these data indicate that researchers realize the advantages of acquiring samples from centralized sample banks. These advantages include a lower cost than would be incurred from individual sampling and preparation; availability of analyzed samples; preservation of samples and the possibility of comparing results with others who have worked on the same samples