NH line broadening coefficients and intensities measurement and impurities determination in emerging applications: CCUS, Biomethane and H.

A mid-infrared quantum cascade laser (Mid-IR QCL) coupled with a Single Pass Cell and a Multi Pass Cell, was utilized to measure ammonia (NH) absorption spectroscopic parameters and determine NH impurities toward three emerging applications. We for the first time measured the pressure broadening coefficients perturbed by Air, O, N, He, CO, CH, and H and the line intensities of six NH transition lines near 1084.6 cm.

Exploring the Effect of Different Reactivity Promoters on the Oxidation of Ammonia in a Jet-Stirred Reactor.

The low reactivity of ammonia (NH) is the main barrier to applying neat NH as fuel in technical applications, such as internal combustion engines and gas turbines. Introducing combustion promoters as additives in NH-based fuel can be a feasible solution. In this work, the oxidation of ammonia by adding different reactivity promoters, i.

Reaction kinetics of hydrogen atom abstraction from isopentanol by the H atom and HO˙ radical.

Isopentanol is a potential next-generation biofuel for future applications to Homogeneous Charge Compression Ignition (HCCI) engine concepts. To provide insights into the combustion behavior of isopentanol, especially to its auto-ignition behavior which is linked both to efficiency and pollutant formation in real combustion systems, detailed quantum chemical studies for crucial reactions are desired. H-Abstraction reaction rates from fuel molecules are key initiation steps for chain branching required for auto-ignition.

Theoretical Investigation of Intramolecular Hydrogen Shift Reactions in 3-Methyltetrahydrofuran (3-MTHF) Oxidation.

3-Methyltetrahydrofuran (3-MTHF) is proposed to be a promising fuel component among the cyclic oxygenated species. To have detailed insight of its combustion kinetics, intramolecular hydrogen shift reactions for the ROO to QOOH reaction class are studied for eight ROO isomers of 3-MTHF. Rate constants of all possible reaction paths that involve formation of cyclic transition states are computed by employing the CBS-QB3 composite method.

Experimental and Modeling Study of the Temperature and Pressure Dependence of the Reaction C2H5 + O2 (+ M) → C2H5O2 (+ M).

The reaction C2H5 + O2 (+ M) → C2H5O2 (+ M) was studied at 298 K at pressures of the bath gas M = Ar between 100 and 1000 bar. The transition from the falloff curve of an energy transfer mechanism to a high pressure range with contributions from the radical complex mechanism was observed. Further experiments were done between 188 and 298 K in the bath gas M = He at pressures in the range 0.

Reaction kinetics of hydrogen abstraction reactions by hydroperoxyl radical from 2-methyltetrahydrofuran and 2,5-dimethyltetrahydrofuran.

Highly accurate rate parameters for H-abstraction reactions by HO2 radicals are needed for development of predictive chemical kinetic models for ignition. In this article, we report the rate coefficients for reaction of hydroperoxyl radical (HO2) with 2-methyltetrahydrofuran (MTHF) and 2,5-dimethyltetrahydrofuran (DMTHF) computed employing CBS-QB3 and CCSD(T)/cc-pVTZ//B3LYP/cc-pVTZ level of theory in the temperature range of 500-2000 K. Conventional transition state theory (CTST) with hindered rotor approximation for low frequency torsional modes and RRHO (rigid-rotor harmonic oscillator) approximation for all other vibrational modes is employed to evaluate the high pressure rate constants as a function of temperature.

Low-temperature combustion chemistry of biofuels: pathways in the initial low-temperature (550 K-750 K) oxidation chemistry of isopentanol.

The branched C(5) alcohol isopentanol (3-methylbutan-1-ol) has shown promise as a potential biofuel both because of new advanced biochemical routes for its production and because of its combustion characteristics, in particular as a fuel for homogeneous-charge compression ignition (HCCI) or related strategies. In the present work, the fundamental autoignition chemistry of isopentanol is investigated by using the technique of pulsed-photolytic Cl-initiated oxidation and by analyzing the reacting mixture by time-resolved tunable synchrotron photoionization mass spectrometry in low-pressure (8 Torr) experiments in the 550-750 K temperature range. The mass-spectrometric experiments reveal a rich chemistry for the initial steps of isopentanol oxidation and give new insight into the low-temperature oxidation mechanism of medium-chain alcohols.

Contribution of the radical-complex mechanism to the rate of the reaction CH(3) + O(2) (+ M) → CH(3)O(2) (+ M) at high pressures.

Earlier experimental studies of the falloff curves of the reaction CH(3) + O(2) (+ M) → CH(3)O(2) (+ M) in the bath gases M = Ar and N(2) (Fernandes et al., J. Phys.

Formally direct pathways and low-temperature chain branching in hydrocarbon autoignition: the cyclohexyl + O2 reaction at high pressure.

The OH concentration in the Cl-initiated oxidation of cyclohexane has been measured between 6.5-20.3 bar and in the 586-828 K temperature range by a pulsed-laser photolytic initiation-laser-induced fluorescence method.

Shock wave study on the thermal unimolecular decomposition of allyl radicals.

We present the first direct study on the thermal unimolecular decomposition of allyl radicals. Experiments have been performed behind shock waves, and the experimental conditions covered temperatures ranging from 1125 K up to 1570 K and pressures between 0.25 and 4.

Falloff curves for the Reaction CH3 + O2 (+ M) --> CH3O2 (+ M) in the pressure range 2-1000 bar and the temperature range 300-700 K.

The reaction CH(3) + O(2) (+M) --> CH(3)O(2) (+M) was studied in the bath gases Ar and N(2) in a high-temperature/high-pressure flow cell at pressures ranging from 2 to 1000 bar and at temperatures between 300 and 700 K. Methyl radicals were generated by laser flash photolysis of azomethane or acetone. Methylperoxy radicals were monitored by UV absorption at 240 nm.