Abstract |
The report gives results of a study to help characterize the various waste streams by identifying the mass flow rates of the minor and trace elements in each waste stream of a coal-fired utility boiler. In obtaining the mass balances for 28 elements, the inlet and outlet flows associated with three major pieces of equipment were used: the pulverizer, boiler, and electrostatic precipitator (ESP); Kingston Unit 6 has two ESPs. Thus, the mass balance presented reflected a good picture of Unit 6 at near-full-load operation. The mass imbalance for the entire system ranged from -12.5 to +6.3%. However, the mass imbalance for each element was quite different: in many cases, it greatly exceeded + or -12.5%. Nevertheless, 10 elements--Al, Be, Ca, Cr, Fe, Mg, S, Si, Ti, and V--had imbalances of < + or -10%; these elements represented about 93% of the total fly ash and bottom ash mass flow rates. Improved sampling for elements in the vapor phase is needed because most concentrations were below detection limits. Improved sampling for both the bottom ash and inlet to the mechanical collector would drastically improve the mass flow rate estimates and remove some of the assumptions of this report. |