Hexafluoropropylene (HFP) is used as an advanced fire extinguishing agent with high thermal stability, excellent fire suppression performance, and environmentally friendly characteristics. In this study, the inhibition mechanism of HFP during H₂ combustion was analyzed, focusing on its reaction behavior with H and OH radicals to verify its interruption of the combustion chain reaction by scavenging key reactive radicals. The unimolecular pyrolysis process of HFP was investigated to characterize the heat absorption effect when it dissociates into small molecular fragments. The gas-phase kinetic properties of the proposed reaction pathway were analyzed by combining high-level quantum chemical calculations with the RRKM/master equation. The results show that the unimolecular dissociation reaction of HFP has a significant rate difference at low temperatures, but this difference gradually decreases with increasing temperature. In the substitution reaction pathway, the reaction rates of HFP with H and OH were much higher than those of H-abstraction, suggesting that it has an important influence in inhibiting H₂ combustion. In addition, the addition reaction of HFP with H and OH also plays a key role in inhibiting combustion at low temperatures due to the presence of CC double bonds in the molecule. It is particularly noteworthy that the rate of the addition reaction of HFP with H increases significantly with increasing temperature, while the rate of the addition reaction with OH is lower than that of the former at high temperatures. The present study lays a data foundation for the establishment of a more accurate kinetic mechanism of combustion inhibition, which is of great significance for the design of new flame retardants.

This study examines the issue of wind power smoothing in renewable-energy-grid integration scenarios. Under the “dual-carbon” policy initiative, large-scale renewable energy integration (particularly wind power) has become a global focus. However, the intermittency and uncertainty of wind power output exacerbate grid power fluctuations, posing challenges to power system stability. Consequently, smoothing strategies for wind power energy storage systems are desperately needed to improve operational economics and grid stability. According to current research, single energy storage technologies are unable to satisfy both the system-level economic operating requirements and high-frequency power fluctuation compensation at the same time, resulting in a trade-off between economic efficiency and precision of frequency regulation. Therefore, hybrid energy storage technologies have emerged as a key research focus in wind power energy storage. This study employs the SE-SGMD method, utilizing the distinct characteristics of lithium batteries and supercapacitors to decompose frequency regulation commands into low- and high-frequency components via frequency separation strategies, thereby controlling the output of supercapacitors and lithium batteries, respectively. Additionally, the GA-GWO algorithm is applied to optimize energy-storage-system configuration, with experimental validation conducted. The theoretical contributions of this study include the following: (1) introducing the SE-SGMD frequency separation strategy into hybrid energy storage systems, overcoming the performance limitations of single energy storage devices, and (2) developing a power allocation mechanism on the basis of the inherent properties of energy storage devices. In terms of methodological innovation, the designed hybrid GA-GWO algorithm achieves a balance between optimization accuracy and efficiency. Compared to PSO-DE and GWO-PSO, the GA-GWO energy storage system demonstrates improvements of 21.10% and 17.47% in revenue, along with reductions of 6.26% and 12.57% in costs, respectively.

With the development of new synthetic methods, 2-vinylfuran (V2F) has become a potential renewable biofuel. In this work, the potential energy surfaces for the V2F unimolecular dissociation reaction, the H-addition reaction, and the H-abstraction reaction were constructed at the G4 level. The temperature- and pressure-dependent rate constants for the relevant reactions on the potential energy surfaces were calculated by solving the master equation based on the transition state theory and Rice-Ramsperger-Kassel-Marcus theory. The results show that the rate constant for the intramolecular H-transfer reaction of V2F with H atoms from the C(5) site to the C(4) site to form 2-vinylfuran-3(2H)-carbene, followed by the decomposition to form h145te3o, is the highest. The rate constants for the H-abstraction reaction of V2F with H atoms were the largest at C(6) on the branched chain, followed by C(7), and the rate constants for the H-abstraction reaction at C(3), C(4), and C(5) on the furan ring were not competitive. Negative temperature coefficient effects are observed for the rate constants of the addition reactions of V2F with H atoms at low pressures, with the H-addition rate constant at the C(5) site being the largest. This work not only provides the necessary rate constants for the reaction mechanism of V2F combustion but also provides theoretical guidance for the practical application of furan-based fuels.

With the development of synthetic methods, 2-acetylfuran (AF2) has become a potential biomass fuel. The potential energy surfaces of AF2 and OH including OH-addition reactions and H-abstraction reactions were constructed by theoretical calculations at the CCSDT/CBS/M06-2x/cc-pVTZ level. The temperature- and pressure-dependent rate constants of the relevant reaction pathways were solved based on transition state theory and Rice-Ramsperger-Kassel-Marcus theory, as well as Eckart tunneling effect correction. The results showed that the H-abstraction reaction on CH₃ on the branched chain and the OH-addition reaction at the C (2) and C (5) sites on the furan ring were the main reaction channels in the reaction system. At low temperatures, the AF2 and OH-addition reactions dominate, and the percentage decreases gradually to zero with increasing temperature, and at high temperatures, the H-abstraction reactions on the branched chains become the most dominant reaction channel. The rate coefficients calculated in the current work improve the combustion mechanism of AF2 and provide theoretical guidance for the practical application of AF2.

HFC-236fa (1,1,1,3,3,3-hexafluoropropane) is regarded as a potential fire extinguishing alternative to halon, and the present study delves into its mechanism in hydrogen combustion suppression. Based on the master equation solved by the transition state theory, the reaction kinetics of HFC-236fa were analyzed, revealing that it tends to undergo heat-absorbing reactions when dissociating into smaller species. The study focuses on the key roles of hydrogen atoms (H) and hydroxyl radicals (OH) in the radical scavenging reaction. The results show that the differences in the rate constant of the unimolecular dissociation and intramolecular elimination reactions of HFC-236fa are significant at low temperatures, and the differences gradually decrease with increasing temperatures. The reaction generating CF₃CHCF₂ and HF was the fastest rate reaction channel, suggesting that it plays an important role in combustion inhibition. Overall, the combustion inhibition mechanism of HFC-236fa is mainly dominated by the H-abstraction reaction of the OH in the carbon center, while the trifluoromethyl-related reaction contributes little to the inhibition. This study provides an important theoretical basis for the design and evaluation of fire extinguishing agents.

Oxymethylene ether-2 (CH3-O-CH2-O-CH2-O-CH3, OME2), a carbon-neutral fuel, was hydrogenated from CO2 captured in air or exhaust gases and reused for synthesis with renewable electricity. In the current work, two different potential energy surfaces (PESs) for the reaction of OME2 radicals with O-2 were constructed at the CCSD(T)/CBS//M062X/6-311++G(d,p) level. Based on the Rice-Ramsperger-Kassel-Marcus (RRKM) theory and transition state theory, the temperature- and pressure-dependent rate constants for the relevant reactions on the PES were calculated by solving the master equation. The Arrhenius equation has been used to fit the temperature- and pressure-dependent reaction rate constants. The main reaction channels on the PES are discussed, showing that initial adduct generation and intramolecular H-transfer reactions are the key reaction channels for low-temperature combustion. Among them, the HO2 concerted elimination reaction channel needs to overcome higher energy barriers leading to uncompetitive HO2 concerted elimination reactions. The calculated rate constants were updated to the OME2 combustion model, and the updated model is in considerable agreement with experimentally measured data on the ignition delay time in the shock tube. The present work provides support for further studies on the oxidation reaction of long-chain OME..