Effects of an environmentally-friendly, inexpensive composite iron-sodium catalyst on coal gasification

摘要

The objective of this research is to study the effect of the composite catalyst, FeCO_3-Na_2CO_3, on gasification of a low-sulfur sub-bituminous Wyodak coal from the Powder River Basin (PRB) of Wyoming. The catalytic effects of the composite catalysts were evaluated by comparing their effluent gas compositions and carbon conversion kinetics to those achieved in the presence of either FeCO_3 or Na_2CO_3 catalyst alone or without the presence of any catalyst. All of the evaluation work was conducted in a fixed bed gasifier at atmospheric pressure. Compared to raw coal with no catalyst, the composite catalyst is efficient in increasing the carbon conversion rate constant by as much as two times within the 700-800 ℃ range due to its ability to reduce the activation energy of gasification by about 30-40%. Compared to pure sodium and iron catalysts, the composite catalyst can increase the yields of desired products H_2 and CO at 800 ℃ by 15% and 40%, respectively. The composite catalyst can not only synergize the advantages, but also overcome the challenges of pure iron or pure sodium based catalytic coal gasification processes.