STRATEGIES AND TECHNOLOGY FOR MANAGING HIGH-CARBON ASH

The overall objective of the present project is to identify and assess strategies and solutions for the management of industry problems related to carbon in ash. Specific research issues to be addressed include: (1) the effect of parent fuel selection on ash properties and adsorptivity, including a first ever examination of the air entrainment behavior of ashes from alternative (non-coal) fuels; (2) the effect of various low-NOx firing modes on ash properties and adsorptivity; and (3) the kinetics and mechanism of ash ozonation. This data will provide scientific and engineering support of the ongoing process development activities. During this third project period, an extensive battery of surface analysis tools was used to characterize the surfaces of untreated, air-oxidized, and ozone-treated carbons. Most of the work focused on carbon black chosen as a model carbon material suitable for understanding the fundamental surface mechanisms without interference from inorganic matter. In addition to the XPS work described in previous reports, the overall analytical test battery includes: FTIR spectrometry, thermal desorption in nitrogen and in hydrogen/helium, mixtures, surface acidity, hygroscopic behavior, contact angle measurement with standard liquids to determine surface energy and its polar and dispersive components. Most of this characterization work was completed this quarter, with the remainder planned for next quarter. The present report gives only a brief overview of the new data. By the end of next quarter, a complete picture of the ozone surface mechanism should be at hand and a comprehensive discussion of this phase of the work will be presented in that report--the fourth period covering March 1, 2002 to August 31, 3002