Elementary mechanism for gas phase mercury conversion in H2, O2, chloro and bromo C1-hydrocarbon and NOx combustion environments

Document Type

Conference Proceeding

Publication Date

1-1-2009

Abstract

Emissions of gaseous mercury from combustion sources are one of the major environmental concerns facing power generators. The removal of mercury by conversion to mercury halides is evaluated by use of an elementary reaction mechanism that is developed from fundamental principles of thermodynamics and statistical mechanics. Thermochemical properties have been calculated for needed species using CBS-QB3 and density functional methods, and an elementary reaction mechanism have been constructed. . Elementary reaction mechanisms have been constructed for: (i.) Hg halides, Hg hydroxides and Hg halide-hydroxides, (ii.) bromine and C1 bromocarbons, (iii.) H2/O2, (iv.) chlorine and C1 chlorocarbons, (v.) NOx, nitrogen and C1 nitrogen compounds. Comparisons of mercury loss versus halogen, halocarbon, H2, H2O, O2, CH4, and NOx presence in a typical combustion effluent stream are performed. Results illustrate that bromine results in a higher conversion than bromine. Moreover H2 and H2O inhibit the conversion of mercury, whereas the presence of some O2 is important; it oxidizes hydrogen and hydrocarbons to H2O and CO2, allowing the Cl or Br to oxidize the Hg. Nitrogen oxides decrease the conversion of mercury through catalytic reactions that remove chlorine and bromine radicals.

Identifier

84946544134 (Scopus)

ISBN

[9781615676682]

Publication Title

Fall Meeting of the Eastern States Section of the Combustion Institute 2009

First Page

182

Last Page

203

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