Catalytic gasification of a Powder River Basin coal with CO2 and H2O mixtures

• Effect of sodium and iron on coal gasification with H2O and CO2 mixtures was studied.
• H2 yield was decreased by the added catalysts and the increasing reaction temperature.
• Sodium and iron in coal char during gasification were characterized by XRD and SEM/EDS.
• Sodium had better distribution and catalytic performance than iron in the coal gasification under the tested conditions.

CO2 capture and utilization caused more and more public attention because of its environmental impact. The objective of this work was to study the catalytic gasification of a sub-bituminous coal from the Powder River Basin (PRB) using a CO2 and H2O mixture as the gasifying agent. Sodium and iron, in the form of inexpensive compounds, were chosen to catalyze the coal gasification. The experiments were conducted between 700 and 900 °C in a fixed-bed laboratory gasifier under the atmospheric pressure. Results show that the added catalysts had an effect on the composition of gas products in a way different from it in pure steam gasification. Fitting models for kinetic data were examined and the results show that addition of 3 wt% Na or 3 wt% iron led to a 28.0% or a 19.5% reduction in the activation energy of the gasification reaction, respectively. The sodium and iron in the coal char were characterized and the results show that sodium is more evenly distributed than iron during gasification. Suggestions for improving the catalysts' performance in coal gasification were proposed accordingly.

Figure optionsDownload high-quality image (233 K)Download as PowerPoint slide