Advances in Combustion Chemistry: Mechanisms and Applications

Emphasizing hydrocarbon reactions and kinetics, this paper investigates the chemical mechanisms of burning. Recent developments and uses in the fields of energy and environmental sciences are examined to underline potential directions of study.

Introduction to Combustion Chemistry

Comprising about 90% of the world’s primary energy consumption, combustion chemistry is a basic feature of energy generation (Fiorina et al., 2014). This field includes complex processes including radical assaults on hydrocarbons or hydrocarbon breakdown generating alkyl radicals (Power et al., 2019). Gas phase chemistry and greatly affect flame structure and computational combustion modeling (Okyay et al., 2018), so the chemistry of combustion is closely related to the generation of soot and char.

Over time, combustion chemistry has evolved really dramatically. From the first discovery of platinum-catalyzed combustion of gaseous mixtures by Davy to current investigations on the ignition and flame propagation of dual fuels like ammonia/n-heptane, continuous efforts have been made to grasp the complexity of combustion reactions (Jacobse et al., 2017; Zhao, 2023). Processes like hydrogen atom transfer have become more important in many different fields, including hydrocarbon combustion and atmospheric chemistry (Darcy et al., 2018).

Development of models that help to quantify uncertainty and improve our knowledge of combustion processes has been made possible by advances in combustion chemistry (Wang & Sheen, 2015). Studies have shown that parameters including fuel qualities and injection timing can clearly affect combustion modes; autoignition chemistry is therefore quite important in defining combustion properties (Naser et al., 2017). Moreover, the use of molecular dynamics simulations has shed light on the influence of electric fields on ethanol oxidation events, therefore exposing comprehensive data on chemical reactions during combustion (Luo, 2021).

A multifarious field with important environmental consequences as well as driving energy generation is combustion chemistry. Optimizing energy processes, reducing emissions, and supporting the evolution of greener technology all depend on an awareness of the complex dynamics underlying combustion.

Mechanisms and Kinetics of Combustion Reactions

Particularly involving hydrocarbons, combustion reactions are complex events impacted by variables including temperature and pressure. Chemical kinetics of hydrocarbon combustion have been extensively investigated in order to clarify reaction paths, intermediates, and the effect of ambient factors on reaction speeds Elbe 1955

Studies on noble metals such as Rhodium have shown that hydrocarbons oxidize using certain chemical paths. This process starts with hydrocarbon dissociation creating methylidyne (CH), which is then oxidised to CHO and finally dissociates to CO and H (Inderwildi et al., 2008). This emphasizes the need of knowing the processes by which hydrocarbons burn to produce different intermediates and goods.

The rates of combustion events are strongly influenced by temperature and pressure. Often used to explain the kinetics of combustion events, models grounded on the Arrhenius equation link the rate of reaction to temperature and activation energy (Eskola et al., 2019). Research on the effects of particle size and heating rate on combustion reactions has also looked at how different reaction mechanisms might be connected with different activation energies (Altun et al., 2002).

Furthermore, ReaxFF molecular simulations and other computational techniques have provided understanding of combustion reaction kinetics and processes. These simulations have given a thorough knowledge of main reaction routes during hydrocarbon combustion, so stressing the dominance of bond dissociation reactions in the early stages of combustion and the importance of unimolecular reactions in the first phases of combustion processes (Chen et al., 2018).

Particularly those containing hydrocarbons, the study of combustion processes calls for careful analysis of reaction mechanisms, intermediates, and the effect of temperature and pressure on reaction speeds. Combining computational simulations, theoretical models, and experimental methods helps scientists to constantly find the complex aspects of combustion chemistry, so advancing environmental sustainability and energy production.

Advancements and Applications

Not only in industrial environments, transportation, and energy generation but also in many other sectors thanks to recent technological developments in combustion processes. Low-temperature combustion technologies, such reactivity-controlled compression ignition engines, which provide the twin advantage of lower NOx and soot emissions together with improved fuel economy, are one obvious trend. Paykani and associates (2015).

Advancements in combustion processes have brought creative ideas like thermally stratified compression ignition (TSCI), which uses direct water injection to control temperature distribution before ignition, so allowing cycle-to- cycle control over heat release in low-temperature combustion (Lawler et al., 2017). Furthermore promising in satisfying strict emissions rules and increasing fuel economy in next-generation powertrains is the employment of sophisticated combustion techniques such homogenous charge compression ignition and premixed charge compression ignition (Modiyani et al., 2011).

Regarding the generation of energy, developments in combustion technologies have created fresh opportunities for more effective and environmentally friendly energy creation. For coal-fired power boilers, oxy-fuel combustion technology has become increasingly important for reaching CO2 collection and storage, hence supporting environmental sustainability (Shan et al., 2022). Moreover, the creation of synthetic fuels tailored for particular uses emphasizes the possibility of renewable synthetic fuels to fit very well into current energy and transportation systems (Pregger et al., 2019).

Advances in combustion techniques have also helped transportation; spark-assisted compression ignition (SACI) engines broaden the load range and improve combustion control while keeping great thermal efficiency (Zhou et al., 2018). Furthermore proving the possibility for increased engine efficiency (Zhou et al., 2018) the application of exhaust gas recirculation (EGR) with split injection techniques in engines has shown increases in combustion performance and knock resistance.

Future studies in combustion processes are probably going to concentrate on even more lowering emissions, improving fuel flexibility, and raising energy efficiency. Researchers want to reach sustainable energy solutions that fit decarbonization targets by using advanced combustion ideas such MILD combustion and biofuels (Sabia et al., 2021). Furthermore considered to be very important in progressing technology and reaching more effective energy usage is the incorporation of machine learning techniques for estimating ignition delay and optimizing combustion processes (Molana, 2024).

Finally, recent developments in combustion techniques have not only transformed industrial operations, transportation, and energy generation but also hold the key to solve environmental problems and propel the change towards greener and more sustainable energy systems.

References

Darcy, J., Koronkiewicz, B., Parada, G., & Mayer, J. (2018). A continuum of proton-coupled electron transfer reactivity. Accounts of Chemical Research, 51(10), 2391-2399. https://doi.org/10.1021/acs.accounts.8b00319

Fiorina, B., Veynante, D., & Candel, S. (2014). Modeling combustion chemistry in large eddy simulation of turbulent flames. Flow Turbulence and Combustion, 94(1), 3-42. https://doi.org/10.1007/s10494-014-9579-8

Jacobse, P., Moret, M., Gebbink, R., & Swart, I. (2017). Tracking on-surface chemistry with atomic precision. Synlett, 28(19), 2509-2516. https://doi.org/10.1055/s-0036-1590867

Luo, K. (2021). Reactive and electron force field molecular dynamics simulations of electric field assisted ethanol oxidation reactions. Proceedings of the Combustion Institute, 38(4), 6605-6613. https://doi.org/10.1016/j.proci.2020.06.318

Naser, N., Jaasim, M., Atef, N., Chung, S., & Im, H. (2017). On the effects of fuel properties and injection timing in partially premixed compression ignition of low octane fuels. Fuel, 207, 373-388. https://doi.org/10.1016/j.fuel.2017.06.048

Okyay, G., Bellayer, S., Samyn, F., Jimenez, M., & Bourbigot, S. (2018). Characterization of in-flame soot from balsa composite combustion during mass loss cone calorimeter tests. Polymer Degradation and Stability, 154, 304-311. https://doi.org/10.1016/j.polymdegradstab.2018.06.013

Power, J., Somers, K., Zhou, C., Peukert, S., & Curran, H. (2019). Theoretical, experimental, and modeling study of the reaction of hydrogen atoms with 1- and 2-pentene. The Journal of Physical Chemistry A, 123(40), 8506-8526. https://doi.org/10.1021/acs.jpca.9b06378

Wang, S. and Sheen, D. (2015). Combustion kinetic model uncertainty quantification, propagation and minimization. Progress in Energy and Combustion Science, 47, 1-31. https://doi.org/10.1016/j.pecs.2014.10.002

Zhao, W. (2023). Numerical study on the ignition and flame propagation of ammonia/n-heptane dual fuels. Energy & Fuels, 37(17), 13354-13365. https://doi.org/10.1021/acs.energyfuels.3c02251

Altun, N., Kök, M., & Hiçyılmaz, C. (2002). Effect of particle size and heating rate on the combustion of silopi asphaltite. Energy & Fuels, 16(3), 785-790. https://doi.org/10.1021/ef0102519

Chen, Z., Sun, W., & Zhao, L. (2018). Combustion mechanisms and kinetics of fuel additives: a reaxff molecular simulation. Energy & Fuels, 32(11), 11852-11863. https://doi.org/10.1021/acs.energyfuels.8b02035

Elbe, G. (1955). Chemical kinetics of hydrocarbon combustion. Proceedings of the Combustion Institute, 5(1), 79-85. https://doi.org/10.1016/s0082-0784(55)80015-x

Eskola, A., Pekkanen, T., Joshi, S., Timonen, R., & Klippenstein, S. (2019). Kinetics of 1-butyl and 2-butyl radical reactions with molecular oxygen: experiment and theory. Proceedings of the Combustion Institute, 37(1), 291-298. https://doi.org/10.1016/j.proci.2018.05.069

Inderwildi, O., Jenkins, S., & King, D. (2008). Mechanistic studies of hydrocarbon combustion and synthesis on noble metals. Angewandte Chemie, 47(28), 5253-5255. https://doi.org/10.1002/anie.200800685

Lawler, B., Splitter, D., Szybist, J., & Kaul, B. (2017). Thermally stratified compression ignition: a new advanced low temperature combustion mode with load flexibility. Applied Energy, 189, 122-132. https://doi.org/10.1016/j.apenergy.2016.11.034

Modiyani, R., Kocher, L., Alstine, D., Koeberlein, E., Stricker, K., Meckl, P., … & Shaver, G. (2011). Effect of intake valve closure modulation on effective compression ratio and gas exchange in turbocharged multi-cylinder engines utilizing egr. International Journal of Engine Research, 12(6), 617-631. https://doi.org/10.1177/1468087411415180

Molana, M. (2024). Machine learning approaches for predicting ignition delay in combustion processes: a comprehensive review. Industrial & Engineering Chemistry Research, 63(6), 2509-2518. https://doi.org/10.1021/acs.iecr.3c04097

Paykani, A., Kakaee, A., Rahnama, P., & Reitz, R. (2015). Progress and recent trends in reactivity-controlled compression ignition engines. International Journal of Engine Research, 17(5), 481-524. https://doi.org/10.1177/1468087415593013

Pregger, T., Schiller, G., Cebulla, F., Dietrich, R., Maier, S., Thess, A., … & Aigner, M. (2019). Future fuels—analyses of the future prospects of renewable synthetic fuels. Energies, 13(1), 138. https://doi.org/10.3390/en13010138

Sabia, P., Sorrentino, G., Ariemma, G., Manna, M., Ragucci, R., & Joannon, M. (2021). Mild combustion and biofuels: a minireview. Energy & Fuels, 35(24), 19901-19919. https://doi.org/10.1021/acs.energyfuels.1c02973

Shan, S., Chen, B., Zhou, Z., & Zhang, Y. (2022). A review on fundmental research of oxy-coal combustion technology. Thermal Science, 26(2 Part C), 1945-1958. https://doi.org/10.2298/tsci210329238s

Zhou, L., Dong, K., Hua, J., Wei, H., Chen, R., & Han, Y. (2018). Effects of applying egr with split injection strategy on combustion performance and knock resistance in a spark assisted compression ignition (saci) engine. Applied Thermal Engineering, 145, 98-109. https://doi.org/10.1016/j.applthermaleng.2018.09.001