Kinetics of Ethylene Glycol: The first validated reaction scheme and first measurements of ignition delay times and speciation data

Abstract

The reaction kinetics of Ethylene Glycol (EG) is studied, due to its similarity in chemical composition and physical properties, as a model fuel for pyrolysis oil. Recently, the combination of fast pyrolysis of residual biomass and subsequent gasification of the pyrolysis oil has gained high interest. In the gasification process, oxygen is often used as a gasifying agent (e.g. autothermal gasification) which led us to study EG under oxidation condition. This study has experimental and modeling objectives: We obtain novel experimental data that we use for validation of our EG oxidation model that enable predictive modeling and optimization of gasifiers through multi-dimensional CFD simulations. Both, detailed and reduced skeletal models are obtained. The validation data needed for the model is studied in two different types of experiments namely, (1) ignition delay times obtained behind reflected shock waves in the temperature range of 800-1500 K at 16 bar and, (2) quantitative species profiles measured in a high temperature flow reactor setup for fuel equivalence ratios  = 1.0 and 2.0 in the temperature range of 700-1200 K. Both experiments are performed in the EG-system for the first time providing the relevant basis for the understanding on how EG decomposes and for the optimization of the reaction mechanism. The influence of different product channels on the reactivity of the EG system is investigated and leads us to pose the question, if enol can be formed in this combustion (oxidative) environment.

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

“…Careful characterization of the system allows assignment of a distinct axial temperature profile for each oven temperature, which is afterwards used as input for kinetic modeling using the plug flow approximation. 67 Due to the change in temperature, Reynolds numbers vary from 113-161, which assures the plug flow approximation; also, the residence time of gas ranges from 1.2-1.8 s. 66 The experimental and numerical methods have been shown to give valid targets for development of kinetic mechanisms. [67][68][69][70] A brief summary of the experimental conditions may be found in Table 1; the original publication gives more details.…”

“…67 Due to the change in temperature, Reynolds numbers vary from 113-161, which assures the plug flow approximation; also, the residence time of gas ranges from 1.2-1.8 s. 66 The experimental and numerical methods have been shown to give valid targets for development of kinetic mechanisms. [67][68][69][70] A brief summary of the experimental conditions may be found in Table 1; the original publication gives more details. 3 For the present study, the full dataset was reanalyzed with respect to soot precursors and aromatic species.…”

“…As was done previously, the experiment was modeled as a plug flow reactor with predefined temperature profiles. 3,66,67 The assumptions made in the modeling are: (1) no axial diffusion, (2) no radial gradients, and (3) uniform axial velocity through the reactor. Therefore, the residence time (t) can be directly transformed to the spatial position (x) in the plug flow reactor model.…”

“…73 For all the temperature profiles, the gas temperature at 1 cm intervals in the reactor was given by a correlation to the respective oven temperature from a scaling procedure based on experimentally determined centerline temperature profiles. 67 To make a fair comparison with the experimental measurement by EI-MBMS and consider the limitation of EI-MBMS on distinguishing isomers, the mole fractions of important isomers predicted by the model were lumped at the end of the reactor and the lumped concentration was used in the model vs. data comparison. In Table S2 (ESI †), the names and structures of the important isomers in the Chu mechanism are listed.…”

A wide-range experimental and modeling study of oxidation and combustion of n-propylbenzene

“…Ignition delay times have been measured in a high pressure shock tube with an internal diameter of 46 mm, a driver section of about 10 m and a driven section of 3.25 m in length [31]. The driven section was heated to 433 K. He/Ar mixtures were used to achieve tailored interface conditions.…”