Pyrolysis Gas Composition for a Phenolic Impregnated Carbon Ablator Heatshield

Published physical properties of phenolic impregnated carbon ablator (PICA) are compiled, and the composition of the pyrolysis gases that form at high temperatures internal to a heatshield is investigated. A link between the composition of the solid resin, and the composition of the pyrolysis gases created is provided. This link, combined with a detailed investigation into a reacting pyrolysis gas mixture, allows a consistent, and thorough description of many of the physical phenomena occurring in a PICA heatshield, and their implications, to be presented

Biologically derived diesel fuel and NO formation

International audiencePart 1 of this two part series presented a chemical kinetic model for the simulation of high pressure shock tube pyrolysis and oxidation data of two representative biodiesel surrogate components and the application of this model for predicting prompt NO at practical diesel combustion conditions. The present work discusses in greater detail the model’s development, structure, and rate parameters as well as expands the model’s validation range to include complementary 10 atm jet stirred reactor (JSR) oxidation experiments conducted at lower temperatures (550–1200 K) and longer reaction times of 0.7 s. In addition, shock tube ignition delay measurements of 1-heptene and 1,6-heptadiene, analogs of the hydrocarbon side chains of the methyl esters, have also been performed and are presented to further constrain the model

Theoretical study of unimolecular decomposition of catechol

This study develops the reaction pathway map for the unimolecular decomposition of catechol, a model compound for various structural entities present in biomass, coal, and wood. Reaction rate constants at the high-pressure limit are calculated for the various possible initiation channels. It is found that catechol decomposition is initiated dominantly via hydroxyl H migration to a neighboring ortho carbon bearing an H atom. We identify the direct formation of o-benzoquinone to be unimportant at all temperatures, consistent with the absence of this species from experimental measurements. At temperatures higher than 1000 K, water elimination through concerted expulsion of a hydroxyl OH together with an ortho H becomes the most significant channel. Rice-Ramsperger-Kassel-Marcus simulations are performed to establish the branching ratio between these two important channels as a function of temperature and pressure. All unimolecular routes to the reported major experimental products (CO, 1,3-C4H6 and cyclo-C 5H6) are shown to incur large activation barriers. The results presented herein should be instrumental in gaining a better understanding of the decomposition behavior of catechol-related compounds