Hydrogen production via steam gasification of ash free coals

The kinetics of the coal to hydrogen conversion can be significantly enhanced by introducing catalysts. The catalysts are, however, commonly deactivated by irreversible interaction with mineral matters in coal. This work addresses hydrogen production via steam gasification of ash free coals. Following the production of ash free coals (AFCs) derived from various raw coals (brown, bituminous, and coking coal), fixed-bed steam gasification of the AFCs was performed as a function of temperature and which was compared with one another and also with that of the matching raw coals. In the absence of a catalyst, AFCs produced from different parent coals exhibited similarly low gasification reactivity, comparable to a high rank coal (coking coal) at 700 °C. As expected, the reaction became faster with increasing temperature in the range, 700–900 °C. The steam gasification of AFCs was highly activated by K2CO3 above 700 °C. It was very likely that water–gas shift reaction associated with the gasification of AFCs was also catalyzed.

► AFCs derived from raw coals of various ranks were produced.
► Gasification behavior of AFCs were characterized.
► Reactivity of AFCs was less dependent on the rank of the parent raw coals.
► The steam gasification of AFCs was highly activated by K2CO3.