Search Results (51)

In this study, citric acid-esterified ginger starches with different esterification degrees (EGSC10, EGSC20, and EGSC30) were prepared via a dry-heat method by adjusting the dosage of citric acid (10%, 20%, 30%, w/w). Their multi-scale structures were systematically characterized, and Pickering high internal phase emulsions (Pickering HIPEs) synergistically stabilized by EGSC30 and β-cyclodextrin (β-CD) were constructed. The results showed that esterification modification reduced the relative crystallinity and short-range order of starch but significantly increased the content of resistant starch (RS) and thermal processing stability, indicating that the ordered regions of starch molecules were reconstructed to form a structural system with better anti-digestion properties. With the increase in the degree of esterification substitution, the surface of starch granules gradually became rough, the particle size increased, the solubility and swelling power decreased, and the contact angle increased. EGSC30 could synergistically stabilize Pickering HIPEs with β-CD. As the total concentration of composite particles increased and the β-CD/EGSC30 mass ratio was optimized to 3:1, the droplet size of Pickering emulsions decreased, the gel strength and storage modulus increased significantly, and the system exhibited typical elastic-dominant gel properties and shear-thinning behavior, with the most compact and stable network structure. The obtained results can promote the deep processing of ginger and provide a reference for the construction of novel food-grade Pickering emulsions. Full article

With the increasing penetration of wind power, enhancing the renewable energy accommodation rate and reducing the carbon footprint of the IES, this study proposes a comprehensive evaluation method to assess the impact of a novel dynamic Green Certificate Trading (GCT) and Green Hydrogen Certificate Trading (GHCT) joint mechanism. First, considering the integration of the IES into the carbon trading market, a coupled dynamic GCT-GHCT framework is established. This framework links dynamic green electricity certificate revenues with green hydrogen certificate revenues, leveraging cross-subsidization to incentivize renewable energy consumption. Subsequently, an optimal operation model for the IES is formulated with the objective of minimizing comprehensive costs, which encompass energy procurement, green certificates, carbon trading, and wind curtailment penalties. A piecewise linearization approach is applied to transform the optimization model into a Mixed-Integer Linear Programming problem for efficient solving. Furthermore, based on the dispatch results, a multidimensional evaluation index system is constructed, extracting key indicators from economic, technical, and environmental perspectives. To ensure the rationality of the evaluation, a dynamic reward–penalty asymmetric cloud matter-element (ACME) comprehensive evaluation method based on game theory combinatorial weighting is introduced to calculate the index weights and the final comprehensive evaluation value. Finally, multi-scenario simulations are conducted to verify the superiority of the integrated GCT-GHCT trading framework. The results reveal that the proposed approach not only maximizes renewable energy integration but also provides a robust decision-making tool for the low-carbon transition of multi-energy systems. Full article

The steam generator is a core component of nuclear power plants that facilitates heat exchange between the primary and secondary circuits, directly impacting the overall operation of the plant in terms of safety and reliability. During prolonged operation, the heat transfer tubes of the steam generator are subjected to erosion, corrosion, and cracking due to high-temperature, high-pressure fluid impact and vibration. Existing in-service inspection strategies for heat transfer tubes generally employ fixed intervals and coverage, failing to effectively differentiate the actual risk of tubes in various regions, leading to wasted inspection resources or safety hazards. This paper proposes a dynamic inspection and plugging management strategy based on flow-induced vibration (FIV) analysis, specifically utilizing the flow stability ratio (FSR). By calculating the FSR of heat transfer tubes, the strategy categorizes them into high-risk, medium-risk, and low-risk regions, and dynamically adjusts inspection frequency and coverage based on these risk levels. Theoretical analysis and validation with actual data demonstrate that this strategy can improve inspection efficiency and ensure the safety of the steam generator. Full article

Supercritical carbon dioxide (SC-CO₂) power cycles offer a promising solution for offshore platforms’ gas turbine waste heat recovery due to their compact design and high thermal efficiency. This study proposes a novel parallel-preheating recuperated Brayton cycle (PBC) using SC-CO₂ for waste heat recovery on offshore gas turbines. An integrated energy, exergy, and economic (3E) model was developed and showed good predictive accuracy (deviations < 3%). The comparative analysis indicates that the PBC significantly outperforms the simple recuperated Brayton cycle (SBC). Under 100% load conditions, the PBC achieves a net power output of 4.55 MW, while the SBC reaches 3.28 MW, representing a power output increase of approximately 27.9%. In terms of thermal efficiency, the PBC reaches 36.7%, compared to 21.5% for the SBC, marking an improvement of about 41.4%. Additionally, the electricity generation cost of the PBC is 0.391 CNY/kWh, whereas that of the SBC is 0.43 CNY/kWh, corresponding to a cost reduction of approximately 21.23%. Even at 30% gas turbine load, the PBC maintains high thermoelectric and exergy efficiencies of 30.54% and 35.43%, respectively, despite a 50.8% reduction in net power from full load. The results demonstrate that the integrated preheater effectively recovers residual flue gas heat, enhancing overall performance. To meet the spatial constraints of offshore platforms, we maintained a pinch-point temperature difference of approximately 20 K in both the preheater and heater by adjusting the flow split ratio. This approach ensures a compact system layout while balancing cycle thermal efficiency with economic viability. This study offers valuable insights into the PBC’s variable-load performance and provides theoretical guidance for its practical optimization in engineering applications. Full article

This study employs CFD simulations carried on ANSYS Fluent 2022 R1 (ANSYS Inc., Canonsburg, PA, USA), to address the design, development, and thermodynamic analysis of a biomass burner, based on mass and energy balances, combustion efficiency, flame temperature, and thermodynamic properties. The prototype incorporates a flow deflector located before the combustion chamber. This component improves the air-fuel mixture to maximise thermal efficiency and minimise pollutant emissions. The burner is specifically designed to use sawdust as fuel and is intended for industrial applications such as heating or drying processes. The integration of the flow deflector results in uniform, complete combustion, achieving 90% thermal efficiency and an adjustable thermal power output of 0–100 kW. Compared to conventional burners, this design reduces CO emissions by 20% and NO_x emissions by 15%, demonstrating significant environmental improvements. The design methodology is based on mass and energy balance equations to evaluate combustion efficiency as a function of the stoichiometric ratio, along with experimental testing. These experimental tests were conducted using an ECOM (America Ltd., Nashua, NH, USA) gas analyser and anemometer. The internal temperature was monitored with a K-type thermocouple (Omega Engineering Inc., Norwalk, CT, USA). The results confirmed the positive influence of the structural design on thermal performance. The proposed burner aims to maximise heat generation in the combustion chamber, offering an innovative alternative for biomass combustion systems. Full article

This research investigates a methane-fueled open gas system, enhanced by Prof. Szewalski’s idea of venting exhaust gases at various turbine stages. It assesses the impact of hydrogen co-combustion, which can range from 0% to 100%, on system parameters. The novel approach increased the gas turbine’s electrical efficiency to 41.25%. Two additional heat exchangers raised the inlet fluid temperature, affecting the exhaust gases entering the turbine. The highest exhaust gas temperature reached was 1491.08 °C. A higher hydrogen ratio significantly lowered CO₂ emissions. The study’s originality lies in its innovative technology combination, allowing flexible combustion adjustments to meet energy demands and fuel availability. The gas turbine model provides a detailed analysis of cooling air at each expander stage, enhancing understanding of efficiency factors. Integration with Power-to-Fuel technology facilitates the creation of energy systems that efficiently store and use renewable energy. This contributes to sustainable energy technology development, crucial for achieving climate goals and reducing emissions. Full article

This review relates the kinetics of anaerobic digestion (AD) to energy outcomes, including typical ranges of methane yields and volumetric methane productivities (down to hourly g L⁻¹ h⁻¹ scales relevant for industrial plants). It further translates these relationships into practical control principles that support stable, high methane productivity. Evidence spans substrate selection and co-digestion with emphasis on carbon/nitrogen (C/N) balance, pretreatment strategies, and reactor operation, linking process constraints with operating parameters to identify interventions that raise performance while limiting inhibition. Improving substrate accessibility is the primary step: pretreatment and co-digestion shift limitation beyond hydrolysis and allow safe increases in organic loading. Typical mesophilic operation involves hydraulic retention times of about 10–40 days for food waste and 20–60 days for different types of livestock manure and slowly degradable energy crops, with stable performance achieved when the solids retention time (SRT) is maintained longer than the hydraulic retention time (HRT). Stability is further governed by sustaining a low hydrogen partial pressure through hydrogenotrophic methanogenesis. Temperature and pH define practicable operating ranges; meanwhile, mixing should minimise diffusion resistance without damaging biomass structure. Early-warning indicators—volatile fatty acids (VFAs)/alkalinity, the propionate/acetate ratio, specific methanogenic activity, methane (CH₄)% and gas flow—enable timely adjustment of loading, retention, buffering, mixing intensity and micronutrient supply (Ni, Co, Fe, Mo). In practice, robust operation is generally associated with VFA/alkalinity ratios below about 0.3 and CH₄ contents typically in the range of 50–70% (v/v) in biogas. The review consolidates typical feedstock characteristics and biochemical methane potential (BMP) ranges, as well as outlines common reactor types with their advantages and limitations, linking operational choices to energy yield in combined heat and power (CHP) and biomethane pathways. Reported pretreatment effects span approximately 20–100% higher methane yields; for example, 18–37% increases after mechanical size reduction, around 20–30% gains at 120–121 °C for thermal treatments, and in some cases nearly a two-fold increase for more severe thermal or combined methods. Priorities are set for adaptive control, micronutrient management, biomass-retention strategies, and standardised monitoring, providing a coherent route from kinetic understanding to dependable energy performance and explaining how substrate composition, pretreatment, operating parameters, and kinetic constraints jointly determine methane and energy yield, with particular emphasis on early-warning indicators. Full article

With the application and continuous development of green energy within the park integrated energy systems (PIESs), environmental pollution and resource depletion caused by traditional energy sources have been effectively mitigated. However, the existing research primarily focuses on fixed operating conditions, leading to significant wastage of renewable energy. To enhance the integration of renewable energy and improve overall energy efficiency, in this paper, a seasonal park integrated energy system (SPIES) based on an adjustable cooling–heating–power ratio (SPIESchpr) strategy is proposed to maximize the energy utilization efficiency and system operational economy. In SPIESchpr, to achieve additional carbon emission reductions, a novel seasonal laddered carbon trading mechanism (SLCTM) is proposed. Compared to traditional carbon trading methods, the SLCTM significantly improves the low-carbon performance of PIES. Finally, the effectiveness of the proposed SPIESchpr is validated through three scenario analyses and a detailed case study of typical daily operations. The experimental results demonstrate that, compared to fixed heat-to-cool ratios and conventional carbon trading mechanisms, the proposed SPIESchpr significantly reduces both total operational costs and carbon emissions during both heating and cooling seasons. Consequently, the proposed SPIESchpr not only enhances the energy efficiency, economic benefits, and carbon reduction potential of PIES but also provides a valuable reference for year-round operational dispatching strategies. Full article

The integration of renewable energy and power-to-gas (P2G) technology into park-level integrated energy systems (PIES) offers a sustainable pathway for low-carbon development. This paper presents a low-carbon economic dispatch model for PIES that incorporates uncertainties in renewable energy generation and load demand. A novel two-stage P2G, replacing traditional devices with electrolysers (EL), methane reactors (MR), and hydrogen fuel cells (HFC), enhances energy efficiency and facilitates the utilisation of captured carbon. Furthermore, adjustable thermoelectric ratios in combined heat and power (CHP) and HFC improve both economic and environmental performance. A ladder-type carbon trading and green certificate trading mechanism is introduced to effectively manage carbon emissions. To address the uncertainties in supply and demand, the study applies information gap decision theory (IGDT) and develops a robust risk-averse model. The results from various operating scenarios reveal the following key findings: (1) the integration of CCT with the two-stage P2G system increases renewable energy consumption and reduces carbon emissions by 5.8%; (2) adjustable thermoelectric ratios in CHP and HFC allow for flexible adjustment of output power in response to load requirements, thereby reducing costs while simultaneously lowering carbon emissions; (3) the incorporation of ladder-type carbon trading and green certificate trading reduces the total cost by 7.8%; (4) in the IGDT-based robust model, there is a positive correlation between total cost, uncertainty degree, and the cost deviation coefficient. The appropriate selection of the cost deviation coefficient is crucial for balancing system economics with the associated risk of uncertainty. Full article

This study conducts a simulation-based approach to improve microwave (MW) convective drying using a temperature-responsive pulse ratio (TRPR) method. Traditional fixed-time pulse ratio (TimePR) techniques often result in uneven heating and reduced product quality due to uncontrolled temperature spikes. To address this, a physics-based model was developed using COMSOL Multiphysics 6.3, executed on a high-performance computing (HPC) platform. The TRPR algorithm dynamically adjusts MW ON/OFF cycles based on internal temperature feedback, maintaining the maximum point temperature below a critical threshold of 75 °C. The model geometry, food materials (apple) properties, and boundary conditions were defined to reflect realistic drying scenarios. Simulation results show that TRPR significantly improves temperature and moisture uniformity across the sample. The TRPR method showed superior thermal stability over time-based regulation, maintaining a lower maximum COV of 0.026 compared to 0.045. These values are also well below the COV range of 0.05–0.26 reported in recent studies. Moreover, the TRPR system maintained a constant microwave energy efficiency of 40.7% across all power levels, outperforming the time-based system, which showed lower and slightly declining efficiency from 36.18% to 36.29%, along with higher energy consumption without proportional thermal or moisture removal benefits. These findings highlight the potential of the temperature-responsive pulse ratio (TRPR) method to enhance drying performance, reduce energy consumption, and improve product quality in microwave-assisted food processing. This approach presents a scalable and adaptable solution for future integration into intelligent drying systems. Full article

This study demonstrates that hydrogen enrichment in lean-burn spark-ignition engines can simultaneously improve three key performance metrics, thermal efficiency, combustion stability, and nitrogen oxide emissions, without requiring modifications to the engine hardware or ignition timing. This finding offers a novel control approach to a well-documented trade-off in existing research, where typically only two of these factors are improved at the expense of the third. Unlike previous studies, the present work achieves simultaneous improvement of all three metrics without hardware modification or ignition timing adjustment, relying solely on the optimization of the air–fuel equivalence ratio $\lambda$. Experiments were conducted on a six-cylinder engine for combined heat and power application, fueled with hydrogen–natural gas blends containing up to 30% hydrogen by volume. By optimizing only the air–fuel equivalence ratio, it was possible to extend the lean-burn limit from $\lambda \approx 1.6$ to $\lambda >1.9$, reduce nitrogen oxide emissions by up to 70%, enhance thermal efficiency by up to 2.2 percentage points, and significantly improve combustion stability, reducing cycle-by-cycle variationsfrom 2.1% to 0.7%. A defined $\lambda$ window was identified in which all three key performance indicators simultaneously meet or exceed the natural gas baseline. Within this window, balanced improvements in nitrogen oxide emissions, efficiency, and stability are achievable, although the individual maxima occur at different operating points. Cylinder pressure analysis confirmed that combustion dynamics can be realigned with original equipment manufacturer characteristics via mixture leaning alone, mitigating hydrogen-induced pressure increases to just 11% above the natural gas baseline. These results position hydrogen as a performance booster for natural gas engines in stationary applications, enabling cleaner, more efficient, and smoother operation without added system complexity. The key result is the identification of a $\lambda$ window that enables simultaneous optimization of nitrogen oxide emissions, efficiency, and combustion stability using only mixture control. Full article

With the rapid development of energy transformation, the proportion of new energy is increasing, and the efficient trading mechanism of multi-microgrids can realize energy sharing to improve the consumption rate of new energy. A distributed multi-microgrid cooperative energy sharing strategy is proposed based on Nash bargaining. Firstly, by comprehensively considering the adjustable heat-to-electrical ratio, ladder-type positive and negative carbon trading, peak–valley electricity price and demand response, a multi-microgrid system with wind–solar-storage-load and combined heat and power is constructed. Then, a multi-microgrid cooperative game optimization framework is established based on Nash bargaining, and the complex nonlinear problem is decomposed into two stages to be solved. In the first stage, the cost minimization problem of multi-microgrids is solved based on the alternating direction multiplier method to maximize consumption rate and protect privacy. In the second stage, through the established contribution quantification model, Nash bargaining theory is used to fairly distribute the benefits of cooperation. The simulation results of three typical microgrids verify that the proposed strategy has good convergence properties and computational efficiency. Compared with the independent operation, the proposed strategy reduces the cost by 41% and the carbon emission by 18,490 kg, thus realizing low-carbon operation and optimal economic dispatch. Meanwhile, the power supply pressure of the main grid is reduced through energy interaction, thus improving the utilization rate of renewable energy. Full article

This study proposes an improved multi-objective black-winged kite algorithm (MOBKA-QL) integrating Q-learning with adaptive mutation strategies for optimizing multi-objective scheduling in integrated energy systems (IES). The algorithm dynamically selects mutation strategies through Q-learning to enhance solution diversity and accelerate convergence. First, an optimal scheduling model is established, incorporating a carbon capture system (CCS), power-to-gas (P2G), solar thermal, wind power, and energy storage to minimize economic costs and carbon emissions while maximizing energy efficiency. Second, the heat-to-power ratio of the cogeneration system is dynamically adjusted according to load demand, enabling flexible control of combined heat and power (CHP) output. The integration of CCS+P2G further reduces carbon emissions and wind curtailment, with the produced methane utilized in boilers and cogeneration systems. Hydrogen fuel cells (HFCs) are employed to mitigate cascading energy losses. Using forecasted load and renewable energy data from a specific region, dispatch experiments demonstrate that the proposed system reduces economic costs and CO₂ emissions by 14.63% and 13.9%, respectively, while improving energy efficiency by 28.84%. Additionally, the adjustable heat-to-power ratio of CHP yields synergistic economic, energy, and environmental benefits. Full article

Titanium nitride (TiN) is a widely used industrial hard coating material, known for its excellent hardness and chemical stability. However, its relatively high coefficient of friction (COF) often leads to interfacial heat accumulation and adhesive wear during service, limiting its applicability in high-temperature tribological environments. To enhance its tribological performance, a TiN–WS₂ soft–hard composite coating was fabricated on cemented carbide substrates using reactive co-sputtering magnetron deposition. By adjusting the sputtering parameters and target power ratio, a synergistic deposition of the hard (TiN) and lubricating (WS₂) phases was achieved and compared with a pure TiN coating. The results revealed that the incorporation of WS₂ significantly reduced the COF at both room temperature (25 °C) and an elevated temperature (200 °C), with the average values decreasing from 0.61 to 0.39 at 25 °C and from 0.53 to 0.36 at 200 °C. A white light interferometry analysis showed that the TiN–WS₂ coating exhibited narrower wear tracks and less surface damage than TiN at elevated temperatures, demonstrating superior friction-reducing and wear-resistant capabilities. In terms of mechanical properties, the composite coating showed a reduction in the hardness, the reduced elastic modulus (Er), and the adhesion strength by 27.3%, 19.8%, and 9.5%, respectively, compared to pure TiN. These findings indicate that the introduction of a quantitatively controlled lubricating WS₂ phase allows for a balance between nanoscale hardness and wear resistance, offering promising potential for engineering applications under complex working conditions. Full article

The massive integration of renewable electricity places significant regulatory pressure on urban power grids. This has also promoted the development of virtual power plant technology. The air conditioning systems of public buildings, as one of the main cores of virtual power plants, have flexible regulation capability that is difficult to quantify accurately, leading to slow development in practical engineering applications. This study proposes quantifying the flexible regulation capability of public building air conditioning systems based on heat and light transfer coefficient (HTC and LTC). Taking a public building in Shanghai as an example, this study combines 3D modeling and simulation and sliding window and correlation analysis techniques to investigate changes in influencing factors under different time periods, levels of insulation performance, and window-to-wall ratios. Drawing an analogy with energy storage batteries, two quantification indicators, response time (RT) and response energy loss (RL), are proposed and combined with heat and light transmission systems for nonlinear fitting. Finally, a sensitivity analysis of the impact of external environment and building performance is conducted. The results of sliding window and correlation analysis show that surface irradiance has the highest correlation with air conditioning energy consumption (over 0.8). However, through linear and nonlinear fitting, it was found that HTC can better characterize the two key indicators of RT and RL in air conditioning flexible adjustment, with fitting degrees (R²) of 80% and 72%, respectively. The results obtained from this study can provide a quantitative reference for quantification and response control research into the flexible regulation capability of public building air conditioning systems. Full article