Inhibition of hydrogen oxidation by HBr and Br2

Abstract

The high-temperature bromine chemistry was updated and the inhibition mechanisms involving HBr and Br 2 were re-examined. The thermochemistry of the bromine species was obtained using the Active Thermochemical Tables (ATcT) approach, resulting in improved data for, among others, Br, HBr, HOBr and BrO. Ab initio calculations were used to obtain rate coefficients for selected reactions of HBr and HOBr, and the hydrogen/bromine/oxygen reaction mechanism was updated. The resulting model was validated against selected experimental data from literature and used to analyze the effect of HBr and Br 2 on laminar, premixed hydrogen flames. Our work shows that hydrogen bromide and molecular bromine act differently as inhibitors in flames. For HBr, the reaction HBr + H ⇀ ↽ H 2 + Br (R2) is rapidly equilibrated, depleting HBr in favor of atomic Br, which is the major bromine species throughout the reaction zone. The chain-breaking

High‐temperature rate constants for H/D + C2H6 and C3H8

“…The two most current versions of the ATcT TN (ver. 1.110 29–31 and 1.112 32) contain sufficient experimental and theoretical determinations to produce reliable thermochemistry for the reactions studied here (see Table I). As noted previously 31, the thermochemistry of n ‐ and i ‐propyl radicals, for which the listed ATcT values are provisional, relies heavily on the determinations and ATcT‐like analysis of Bodi et al 33.…”

Intumescent fire‐retardant coatings for plastics based on poly(vinylphosphonic acid): Improving water resistance with comonomers

“…The monomers chosen for this study were dimethylvinylphosphonate (DMVP), acrylonitrile (AN), dibromostyrene (DBS), and a reactive polydimethylsiloxane (PDMS). Previously, incorporation of diethyl vinyl phosphonate (analogous to DMVP) in copolymers with MMA has been shown to improve its fire‐retardance, whereas both AN and DBS have the potential to improve fire‐retardance when used as comonomers, the former through its char‐forming abilities and the latter through the release of HBr, a gas‐phase inhibitor of combustion …”

The Importance of Detailed Chemical Mechanisms in Gas Turbine Combustion Simulations

“…The correct prediction of the inhibition of the radical chain propagation during hydrogen ignition and hydrogen oxidation under a wide range of technical relevant conditions [55] as well as the extension of the validation range of detailed syngas (H 2 / CO) combustion model to technical relevant high pressure conditions [56] shows that using reliable thermochemical and kinetic data together allows constructing detailed chemical models with predictive behavior over a wide range of conditions in terms of concentration, pressure, and temperature.…”