Effect of Ultrafine Iron and Mineral Matter on Conversion of Nitrogen and Carbon During Pyrolysis and Gasification of Coal

Abstract

A subbituminous coal was used to determine the distribution of N 2 , NH 3 , and HCN during slow rate heating pyrolysis in He and gasification in 10% CO 2 +He balance. During pyrolysis, the N 2 was the major product followed by NH 3 and HCN. During gasification, the N 2 yields were significantly enhanced and those of NH 3 and HCN decreased. Partial demineralization of coal resulted in a decrease in carbon and nitrogen conversion. This effect was also evident by comparing the nitrogen and carbon conversions of chars prepared at 500 o C from the fresh and demineralized coals. The addition of ultrafine Fe to coal increased conversion of carbon and nitrogen to N 2 during gasification but had little effect during pyrolysis. Thus, during the former more than 80% of the coal nitrogen was released ax N 2 . Also, in the presence of Fe the temperature of N 2 release was decreased by about 100 o C both during pyrolysis and gasification. During gasification of chars prepared at 1000 o C, the conversion of the coal nitrogen to N 2 was much lower than that of carbon