DEVELOPMENT OF HIGH ACTIVITY, COAL-DERIVED, PROMOTED CATALYTIC SYSTEMS FOR NOx REDUCTION AT LOW TEMPERATURES

Calo, Joseph M.

Federal Energy Technology Center (U.S.)

关键词: Desorption;    Chemical Reaction Kinetics;    By-Products;    Spectra;    Activated Carbon;   

DOI  :  10.2172/783591
RP-ID  :  FG26-97FT97267--05
RP-ID  :  FG26-97FT97267
RP-ID  :  783591

美国|英语

来源: UNT Digital Library

【 摘 要 】

This project is directed at an investigation of catalytic NO{sub x} reduction mechanisms on coal-derived, activated carbon supports at low temperatures. Promoted carbon systems offer some potentially significant advantages for heterogeneous NO{sub x} reduction. These include: low cost; high activity at low temperatures, which minimizes carbon loss; oxygen resistance; and a support material which can be engineered with respect to porosity, transport and catalyst dispersion characteristics. During the reporting period, the following has been accomplished: (1) Steady-state reactivity studies in the packed bed reactor were extended to the NO/CO-carbon reaction system as a function of temperature and NO and CO concentrations. It was found that the NO reaction rate increased in the presence of CO, and the apparent activation energy decreased to about 75 {+-} 8 kJ/mol. In addition, the influence of mass transfer limitations were noted at low NO and CO concentrations. (2) The packed bed reactor/gas flow system has been applied to performing post-reaction temperature programmed desorption (TPD) studies of intermediate surface complexes following steady-state reaction. It was found that the amount of CO-evolving intermediate surface complexes exceeded that of the N{sub 2}-evolving surface complexes, and that both increased with reaction temperature. The TPD spectra indicates that both types of complexes desorb late, suggesting that they have high desorption activation energies. Plans for the next reporting period include extending the temperature programmed desorption studies in the packed bed reactor system to the NO/CO reaction system, including exposure to just CO, as well as NO/CO mixtures.