Gasification reactivity of Chilean coals

Abstract

Gasification reactivities of raw and acid-washed coal chars obtained from the three most important coal-bearing regions in Chile have been determined in 0.1 MPa of oxygen using a thermobalance. Oxygen chemisorption capacities of the demineralized chars were also measured gravimetrically at 373 K in 0.1 MPa of oxygen. The subbituminous coals of Catamutun and Peckett are more reactive than the bituminous coals of Lota and Trongol due to the catalytic effect of their inorganic constituents. However, in the absence of catalytically significant mineral matter, coal rank is not an important parameter of char reactivity. The reactivity of chars based on carbon active surface areas, estimated from gravimetric chemisorption measurements, agreed very well with the previously reported value based on active surface areas obtained in a volumetric system. These results supply additional evidence that active surface area is the fundamental parameter that can explain most of the observed differences in the kinetic behaviour of coal chars and carbons in general.