Detailed Reaction Mechanism for 350–400 °C Pyrolysis of an Alkane, Aromatic, and Long-Chain Alkylaromatic Mixture

Abstract

Many technologically important systems involve mixtures of fairly large molecules and relatively unselective chemistry, leading to complex product mixtures. These corresponding reaction networks are quite complex since each molecule in the feed can form many isometric intermediates and a variety of byproducts in addition to its major product. A variety of modeling methods have been developed to attempt to deal with this, but building accurate reaction mechanisms for these complicated systems is challenging, and the methodology is still under development. To showcase the advancements that have been made in automatic generation of large mechanisms, we constructed such a model for a three-component mixture containing species with up to 18 carbon atoms. The generated model is able to predict many of the major and minor products with relatively high accuracy against gold-tube batch pyrolysis data collected for this system. The high fidelity between the predicted species profiles and the experimental data is notable given the low temperature pyrolysis conditions studied, as any errors in ab initio rate parameters become more significant at lower temperatures.

Fast Predictions of Reaction Barrier Heights: Toward Coupled-Cluster Accuracy

“…9 Indeed, recently several research groups have constructed models to quantitatively predict the time-evolution of diverse chemical systems, based largely on parameters derived from quantum chemistry rather than experiment. For example, earlier this year our group has published models for combustion, 10 pyrolysis, 11,12 and the degradation of pharmaceutical compounds. 13 However, because quantum chemistry calculations of rate coefficients are slow, only a small fraction of the numerous rate coefficients in these models have been computed accurately, which can make the predictions somewhat erratic.…”

Detailed Microkinetics for the Oxidation of Exhaust Gas Emissions through Automated Mechanism Generation

“…Using automated mechanism generation software, such as the “Reaction Mechanism Generator” (RMG), − instead of building the microkinetics based on chemical intuition, reduces personal bias and accelerates the procedure of the mechanism construction. RMG is a well-established open-source tool to automatically build comprehensive gas-phase mechanisms for combustion or pyrolysis reactions. − However, RMG has only recently been used for heterogeneously catalyzed reactions. − The publications on the heterogeneous catalysis branch of RMG are focused on demonstrating new features rather than developing a microkinetic model suitable to describe experimental results. Blöndal et al .…”

Detailed microkinetics for the oxidation of exhaust gas emissions through automated mechanism generation

“…RMG is a well-established open-source tool to automatically build comprehensive gas-phase mechanisms for combustion or pyrolysis reactions. [24][25][26][27][28] However, RMG has only recently been used for heterogeneously catalyzed reactions. [29][30][31][32] The publications on the heterogeneous catalysis branch of RMG are focused on demonstrating new features rather than developing a microkinetic model suitable to describe experimental results.…”