Date of Award

1990

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemical Engineering

First Advisor

Arthur M. Sterling

Second Advisor

Wei-Yin Chen

Abstract

The effect of fuel type on reburning of a simulated flue gas containing 1000 ppm of NO is studied. Stable nitrogen species concentrations are provided for reburning experiments with five fuels in a premixed, laminar flow reactor. The reactor was operated at atmospheric pressure and gave a maximum gas temperature of approximately 1100$\sp\circ$C for a residence time near 0.2 seconds. The experimental facility used to collect this data is described including a novel coal feeding device. A new gas chromatographic method used to analyze fixed-nitrogen species is described. For each of the five fuels, the fixed-nitrogen speciation as a function of stoichiometry is studied. The first three fuels, methane, hexane, and benzene, demonstrate the influence of fuel type on homogeneous gas-phase nitrogen chemistry. The last two fuels, lignite coal and bituminous coal, introduce heterogeneous and catalytic effects as well as fuel-bound nitrogen. For lignite coal, the heterogeneous reduction of NO on char and the catalytic conversion of HCN to NH$\sb3$ are shown to be important contributors to N$\sb2$ formation. For lignite coal and bituminous coal the gas-phase nitrogen speciation is separated by origin using isotopically labelled N$\sp{15}$O and GC/MS for isotope separation. Probability analysis is used to show that significant NO reduction occurs through non-NO mechanisms. Nitrogen evolution for both coals is observed to be delayed beyond the onset of NO conversion to N$\sb2$.

Pages

182

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