Investigation into the characteristics of Na2CO3-catalyzed steam gasification for a high-aluminum coal char

摘要

The effect of Na2CO3 additive on the steam gasification characteristics of Sunjiahao (SJH) coal char was studied in the present paper. Na2CO3-catalyzed steam gasification of SJH char was carried out in a thermogravimetric analyzer to study the effect of Na2CO3 loading on the gasification reactivity and in a fixed-bed reactor to investigate the evolution of char structure and the transformation of Na2CO3. The comparison result of the reactivity of char impregnated with various Na2CO3 catalyst loading indicates that the saturation level of Na2CO3 loading is 35 mass%. The catalytic gasification residues were characterized by a N-2 adsorption (77 K) technique, laser Raman spectra, and X-ray diffraction patterns. The analyses results of the BET surface of the catalytic gasification residues at different carbon conversion suggest that the block of Na2CO3 catalyst may lead to the smaller BET surface area of the catalytic gasification residue than that of uncatalyzed gasification residual sample. Raman spectra analyses show that the amount of amorphous carbon structure decreased with the process of catalytic char gasification. The results of XRD reveal that Na2CO3 changes into the mixture of sodium aluminosilicates during steam gasification and turns into NaAlSiO4 after complete gasification.