The Chinese Journal of Process Engineering•2026•DOI: 10.12034/j.issn.1009-606X.225185
Sulfur hexafluoride (SF6), widely used as an insulating gas in high-voltage electrical equipment, possesses a global warming potential (GWP) 25,200 times that of CO2, necessitating efficient degradation technologies. This study employed computational fluid dynamics (CFD) to simulate the thermal catalytic degradation of SF6 in a fixed-bed reactor, integrating models for porous media, heat transfer, turbulence, and chemical kinetics. The simulations revealed significant radial non-uniformities in pressure, velocity, temperature, and species concentration distributions, with temperature identified as the dominant factor influencing degradation efficiency. Radial temperature gradients caused uneven reaction rates, with degradation rates near the wall substantially exceeding those at the central axis, thereby reducing overall SF6 conversion. To address this, structural optimizations were implemented, including reducing the reactor tube diameter and incorporating inert porous media with high thermal conductivity at both ends of the catalytic section. These modifications enhanced radial heat transfer, homogenized the temperature field, and improved the uniformity of reaction rates and species concentrations. Parametric studies on inlet gas velocity showed that both excessively low and high flow rates were detrimental: low velocities led to underutilization of the downstream catalyst and increased energy consumption, while high velocities deteriorated heat transfer and exacerbated radial temperature gradients. The optimal inlet velocity range was determined to be 0.4–0.8 m/s for a reactor tube inner diameter of 10 mm, balancing catalyst utilization, energy consumption, and degradation efficiency. This research provides data-driven guidance for the design and scale-up of SF6 catalytic degradation reactors.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202511047
Ultra-high voltage (UHV) transmission lines are critical infrastructure for China's energy strategy. Compared with conventional voltage lines, UHV lines exhibit nonlinear growth in resource and capital consumption, complex supply chains, and strong spatiotemporal heterogeneity in carbon emission factors, resulting in substantial and uncertain construction-phase emissions. Accurate accounting is essential for achieving carbon peaking and carbon neutrality goals in the power sector. To address issues of ambiguous system boundaries, weak characterization of input parameter uncertainty, and poor cross-year applicability of input-output carbon intensities, this study defines the accounting boundary using budget quotas and develops a hybrid life cycle assessment (HLCA) model. For easily traceable emission sources, process-based LCA (PLCA) is applied, with uncertainty analysis via distribution fitting and Monte Carlo simulation. For difficult-to-trace sources, input-output LCA (IO-LCA) is used with carbon intensity correction. A case study of a ±800 kV transmission line yields a construction-phase carbon emission intensity of 1,858.91 t·km⁻¹ (CO₂ equivalent), with a 95% confidence interval of [1,379.73, 2,486.45] t·km⁻¹. Sobol global sensitivity analysis identifies key emission reduction pathways. The method's validity is confirmed by comparison with existing studies, providing quantitative support for low-carbon design, construction optimization, and carbon auditing of UHV projects.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3895-7
Flexible transparent electrodes are vital for next-generation electronics, but conventional silver nanowire (AgNW) networks suffer from non-uniform current and “hot spots” due to their random arrangement. To address this, we present a facile rubber pressure treatment that enables the controlled self-assembly of ordered AgNW micromesh (Ag NMs) on hydrophilic surfaces. This simple physical treatment simultaneously modifies surface energy and topography through molecular chain transfer from the rubber, creating optimal wetting conditions for coffee-ring assembly. This dual modification transforms droplet evaporation from constant contact angle to constant contact radius mode, enabling the universal fabrication of well-defined Ag NMs on diverse substrates like glass, polymers, and even curved surfaces. The resulting Ag NMs/colorless polyimide (CPI) electrodes (2 cm × 2 cm, ~30 Ω/sq), fabricated via single-step transfer and embedding, demonstrate desirable uniform sheet resistance distribution (<5% variation), outstanding mechanical durability, and environmental stability. These electrodes exhibit superior performance in practical applications, including stable electrical heating (159 ± 3°C at 8 V) with uniform temperature distribution and excellent electromagnetic interference (EMI) shielding (26.4 dB), while maintaining high optical transparency (~78%). This scalable approach offers a promising platform for advanced flexible electronics.