NH3 Formation and Destruction during the Gasification of Coal in Oxygen and Steam

• Published in: Environmental science & technology Vol. 41; no. 15; pp. 5505 - 5509
• Main Authors: Mckenzie, Lachlan J, Tian, Fu-Jun, Li, Chun-Zhu
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.08.2007
• Subjects: Air pollution caused by fuel industries; Ammonia - chemistry; Applied sciences; Atmospheric pollution; Carbon - chemistry; Charcoal - chemistry; Coal; Coal Ash; Combustion and energy production; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Nitric Oxide - analysis; Oxygen - chemistry; Particulate Matter - chemistry; Pollution; Pollution reduction; Prevention and purification methods; Steam; Temperature; Time Factors; Nitrogen oxide; Fluidized bed reactor; Power plant; Pollution control; Pollution prevention; Pollutant formation; Fixed bed reactor; Nitrogen compounds; Chemical degradation; Pollutant emission; Precursor; Operating conditions; Ammonia; Coal power plant; Air pollution; Gasification
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es0705691

This study was conducted to investigate the formation and destruction of NH3 during the gasification of coal in atmospheres containing O2 and steam. A Victorian brown coal was gasified in a novel bench-scale fluidized-bed/fixed-bed reactor at 800 °C in atmospheres containing 2000 ppm O2, 15% H2O, or 2000 ppm O2 + 15% H2O. A NH3 standard gas was also used to study the destruction of NH3 in the gas phase and through gas−solid interactions. Sand, char, and coal ash were all found to enhance the destruction of NH3. An atmosphere containing O2 alone does not favor the conversion of char-N into NH3 but favors the destruction of NH3 through various mechanisms. The introduction of H2O into the gasification system greatly favors the conversion of char-N into NH3 and inhibits the destruction of NH3. The formation and destruction of NH3 in an atmosphere containing 15% H2O was similar to that in an atmosphere containing 15% H2O and 2000 ppm O2, indicating the dominant effects of steam in the formation and destruction of NH3 in a gasifier.