To facilitate the design, analysis, and optimization of the hydrogen liquefaction system, this study developed a MATLAB-based independent simulation program encompassing unit equipment models and exergy analysis models. The program incorporated REFPROP software to accurately calculate fluid physical properties and the heat of conversion between ortho- and parahydrogen. The proposed hydrogen liquefaction process utilized LN₂ precooling, the helium Joule-Brayton cryogenic cycle, and a throttle valve to efficiently produce liquid hydrogen. The simulation results were rigorously validated using the industry standard Unisim Design software. For the 0.5 t/d hydrogen liquefaction system, the exergy efficiency stood at 28.82%, accompanied by a specific energy consumption of 9.82 kW h/kg_LH2. Notably, the compressor contributed the highest exergy loss ratio, accounting for 38.79% of the total. Increasing the compressor efficiency could significantly improve the exergy efficiency and reduce energy consumption. A comparative analysis revealed that at a larger scale of 50 t/d, the exergy losses of both the compressor and expander decreased, whereas the heat exchanger accounted for 36.29% of the total. In conclusion, the independent simulation program established in this study served as a valuable tool for simulating and analyzing the hydrogen liquefaction system, providing a crucial reference for design improvements and optimization efforts.

Non-thermal plasma-driven advanced oxidation is a promising method for treating organic wastewater, which exhibits rapid reaction kinetics and high pollutant removal and does not need chemical reagents. However, its practical application is often limited by high specific energy consumption and the inefficient mass transfer of short-lived reactive species across the gas–liquid interface. This review summarizes the fundamentals of non-thermal plasma chemistry and the process intensification of plasma multiphase reactors by mass transfer enhancement and waste energy-driven conversion. This review focus on four coupling approaches: microbubble-assisted plasma to expand the reactive interfacial area; plasma coupled with hydraulic cavitation to enhance convection and radical formation; plasma–piezoelectric catalysis coupling to harvest hydraulic energy and promote charge-driven reactions; and plasma-assisted Fenton oxidation to improve the utilization of weakly oxidizing species (H₂O₂). The energy efficiency of various plasma-based oxidation systems is compared and discussed clearly. Key remaining challenges are also discussed, including standardized energy efficiency assessment, scale-up and hydrodynamic control, catalyst stability and fouling, by-product formation and toxicity, and long-term operational reliability. Overall, this review aims to provide guidance for developing efficient plasma-based wastewater treatment systems for large-scale applications.

Sustainable power-system operation requires carbon-reduction strategies that are emission-effective, physically deliverable, economically feasible, and compatible with user-side decarbonization claims. As Scope 2 carbon accounting increasingly emphasizes temporal, spatial, and physical consistency, dispatch models need to link user-level carbon claims with network-constrained power delivery. This paper proposes a User-Centric Carbon Cost-Constrained Low-Carbon Dispatch (CCC-LCD) framework that integrates carbon emission flow (CEF), nodal carbon intensity (NCI), network-constrained optimal dispatch, and endogenous demand response. A PTDF-based DC-OPF model represents active-power deliverability, while dual virtual flow variables determine carbon-flow directions endogenously. The model minimizes the target user’s physically traced Scope 2 emissions under a cost-tolerance budget and flexible-load constraints. Case studies on a modified IEEE 14-bus system show that nodal decarbonization is topology-dependent: high-load and high-NCI nodes obtain larger reductions from source-side generation substitution, whereas renewable-adjacent nodes exhibit limited marginal gains. The CEF-DR strategy outperforms single-mechanism cases, indicating the value of coordinating physical carbon-flow constraints with flexible demand. From a sustainability perspective, the proposed framework supports verifiable low-carbon electricity consumption, improves the economic feasibility of user-side decarbonization, and provides a practical dispatch tool for sustainable energy transition and corporate Scope 2 emission reduction.