MINIMIZATION OF CARBON LOSS IN COAL REBURNING

This project develops Fuel-Flexible Reburning (FFR), which combines conventional reburning and Advanced Reburning (AR) technologies with an innovative method of delivering coal as the reburning fuel. The FFR can be retrofit to existing boilers and can be configured in several ways depending on the boiler, coal characteristics, and NOx control requirements. Fly ash generated by the technology will be a saleable byproduct for use in the cement and construction industries. FFR can also reduce NOx by 60%-70%, achieving an emissions level of 0.15 lb/106 Btu in many coal-fired boilers equipped with Low NOx Burners. Total process cost is expected to be one third to one half of that for Selective Catalytic Reduction (SCR). Activities during reporting period included design, manufacture, assembly, and shake down of the coal gasifier and pilot-scale testing of the efficiency of coal gasification products in FFR. Tests were performed in a 300 kW Boiler Simulator Facility. Several coals with different volatiles content were tested. Data suggested that incremental increase in the efficiency of NOx reduction due to the gasification was more significant for less reactive coals with low volatiles content. Experimental results also suggested that the efficiency of NOx reduction in FFR was higher when air was used as a transport media. Up to 14% increase in the efficiency of NOx reduction in comparison with that of basic reburning was achieved with air transport. Temperature and residence time in the gasification zone also affected the efficiency of NOx reduction