Modeling of aromatics formation in fuel-rich methane oxy-combustion with an automatically generated pressure-dependent mechanism

Abstract

An automatic generated mechanism for methane-rich combustion captures the chemistry from small molecules to three-ring aromatic species.

Moving from postdictive to predictive kinetics in reaction engineering

“…Particularly noteworthy is how well the model predicts the changes in the yield of desired products as the feed composition is changed, in some cases quite dramatically. Those interested in this chemistry should also see the follow‐on study of Chu et al 106 In Chu's study, more of the rate and thermo parameters were computed using high accuracy quantum chemistry methods, more reactions of high‐molecular‐weight species were included, and the chemical kinetic model was tested against much more detailed data from laboratory experiments, including measurements of minor byproducts up to C 12 H 8 . It is impressive that it is now possible to accurately predict the yield of C12 byproducts from a C1 feed—there are quite a large number of elementary‐step reactions between C1 and C12, and the reaction network is complex including autocatalytic cycles.…”

“…In all cases, the predicted C 2 H 2 yields are within a factor of 2 of what was measured in the pilot plant, and in most cases the predictions are within 30% of the measured yields. For updated models with many more predictions and comparisons with both pilot plant and laboratory experiments, and full discussion, see 105,106 …”

From benzene to naphthalene: direct measurement of reactions and intermediates of phenyl radicals and acetylene

“…2. In our previous study on methanerich combustion at high temperature (41400 K), the Frenklach route was the most important pathway of naphthalene formation, 6 which involves external H abstraction from phenylacetylene (C 8 H 6 ) forming a C 8 H 5 radical before the second C 2 H 2 addition. However, this route is not expected to be significant under the experimental conditions (600-700 K, 10-50 Torr) of this work where H atoms are generated from H-loss reactions.…”

“…Polycyclic aromatic hydrocarbons (PAHs) have attracted wide attention in combustion as precursors of soot, [1][2][3][4][5] and their build-up process from small molecules has a significant impact on process efficiency and the desired product selectivity. [6][7][8] A number of kinetic models have been proposed to understand the formation of naphthalene, one of the simplest two-ring PAHs, most notably the hydrogen-abstraction-C 2 H 2 -addition (HACA) mechanism starting from benzene and a phenyl radical (C 6 H 5 ) due to its accessible entrance barrier and significant exothermicity. 1,3,9 The potential energy surface (PES) of C 6 H 5 + acetylene (C 2 H 2 ) was reported by Richter et al at the B3LYP/cc-PVDZ level of theory with pressure-dependent rate constant calculations.…”

Predicting polycyclic aromatic hydrocarbon formation with an automatically generated mechanism for acetylene pyrolysis

“…39 Previously, we have described efforts towards expanding the RMG database with the necessary pathways and data to predict formation of one-and two-ring aromatic species. 40 Those efforts included the addition of new kinetics families for propargyl recombination and rate calculations for pathways-forming naphthalene and acenaphthylene, which were combined to generate a pressure-dependent mechanism for methane oxidation using RMG. In this work, we focus on further improving the RMG database with key thermochemical and rate parameters for modeling PAH formation in acetylene pyrolysis.…”