| Autor: |
Panteleev SV; NanoScienece Technology Center, University of Central Florida, 12424 Research Parkway, Ste 400, Orlando, FL, 32826, USA.; N.I. Lobachevsky State University of Nizhny Novgorod, Gagarin Av. 23, Nizhny Novgorod, 603950, Russia., Masunov AE; NanoScienece Technology Center, University of Central Florida, 12424 Research Parkway, Ste 400, Orlando, FL, 32826, USA. amasunov@ucf.edu.; School of Modeling, Simulation, and Training, University of Central Florida, 3100 Technology Pkwy, Orlando, FL, 32826, USA. amasunov@ucf.edu.; South Ural State University, Lenin pr. 76, Chelyabinsk, 454080, Russia. amasunov@ucf.edu.; National Research Nuclear University MEPhI, Kashirskoye shosse 31, Moscow, 115409, Russia. amasunov@ucf.edu., Vasu SS; Center for Advanced Turbomachinery and Energy Research (CATER), Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida, 32816, USA. |
| Abstrakt: |
Fossil fuel oxy-combustion is an emergent technology where habitual nitrogen diluent is replaced by high pressure (supercritical) carbon dioxide. The supercritical state of CO 2 increases the efficiency of the energy conversion and the absence of nitrogen from the reaction mixture reduces pollution by NO x . However, the effects of a supercritical environment on elementary reactions kinetics are not well understood at present. We used boxed molecular dynamics simulations at the QM/MM theory level to predict the kinetics of dissociation/recombination reaction HCO • + [M] ↔ H • + CO + [M], an important elementary step in many combustion processes. A wide range of temperatures (400-1600 K) and pressures (0.3-1000 atm) were studied. Potentials of mean force were plotted and used to predict activation free energies and rate constants. Based on the data obtained, extended Arrhenius equation parameters were fitted and tabulated. The apparent activation energy for the recombination reaction becomes negative above 30 atm. As the temperature increased, the pressure effect on the rate constant decreased. While at 400 K the pressure increase from 0.3 atm to 300 atm accelerated the dissociation reaction by a factor of 250, at 1600 K the same pressure increase accelerated this reaction by a factor of 100. Graphical abstract Formyl radical surrounded by carbon dioxide molecules. |
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