Treatments of low rank coals for improved power generation and reduction in Greenhouse gas emissions

Autor: Pietro. Barilla, G. Domazetis, Bruce D. James, R. Glaisher
Rok vydání: 2008
Předmět:
Zdroj: Fuel Processing Technology. 89:68-76
ISSN: 0378-3820
DOI: 10.1016/j.fuproc.2007.07.004
Popis: Reduction in ash constituents by water washing, and also at specific pH values, was systematically studied for three low-rank coals. Acid treatment removed inorganic constituents if accompanied by efficient water washing; at elevated temperatures this can also reduce moisture. The ash components are present in the coal matrix and also as numerous aluminosilicates particles containing K, Na, Mg, Fe and Ca; acid treatment reduced the ash constituents to mainly quartz and clay particles. The ash chemistry of treated and untreated coals was studied over the temperature range 800 °C to 1400 °C. The ash from treated coals consisted mostly of α-quartz, and when heated at 800 °C to 1500 °C, was transformed into mainly amorphous silica and cristobalite, and melted at 1300–1500 °C. Ash from untreated coals melted at or below 1100 °C. The impact of low rank coals with lower moisture, and also coals with lower ash and moisture, was assessed for power generation using the GateCycle™ package. The results show: (i) moisture reduction lowers CO2/MWh by a small amount but often increases fouling, and (ii) reduction in ash and moisture would eliminate ash fouling and significantly reduce the CO2/MWh compared with current power plant.
Databáze: OpenAIRE