Enhancement of Coal Quality by Microbial Demetalization and Desulfurization

摘要

Microbial demetalization and desulfurization of Illinois No. 6, Pittsburgh No. 8, and Ohio Quarto No. 8 coals were studied. In addition to significant removal of sulfur (80%) and iron (45%); calcium, magnesium, sodium, and small amounts of aluminum and other trace metals were solubilized from all coal types tested. The process variables such as slurry concentration, particle size, degree of agitation, temperature, and CO sub 2 and nutrient concentrations affected demetalization and desulfurization to varying degrees. Microbial demetalization and desulfurization of coals not only reduced the ash quantity but increased the ash fusion temperature of various coal samples by altering the ash composition. An increase in ash fusion temperature is generally beneficial because of reduced slagging and fouling in coal-fired boilers. A preliminary economic analysis indicates that microbial cleaning of coal prior to combustion may be a more suitable process for the upgrading of low rank coals than other convectional methods. (ERA citation 12:015269)