Renewable Energy最新文献

In the process of modified basic NaZSM-5 precursor by its impregnating in M(NO₃)_n (M = Al, Cu, Fe, Co, Ni, Cr, Mn, Zn) or SnCl₄ acidic aqueous solutions, we shed light on the solvation effect of M^x+ cations on surface acid-base strength, and further on enhanced catalytic reactivity. The obtained results indicated that M(Sn, Fe, Cr)/NaZSM-5 prepared with pK_a values of the metal salts <4 present high catalytic reactivity due to their stronger solvation prone to produce acid-base site balance on the surface. To further understand the influence of solvation, the catalytic performance of Sn/NaZSM-5 for methanol, particularly the water-containing methanol dehydration was examined, achieving high conversion and selectivity for high-water-content methanol dehydration. Meanwhile, the catalytic stability test of the catalyst was carried out and above 1000 h run lifetime was actualized without the catalyst surface composition and structure changed.

Optimizing the cathode catalyst layer (CCL) composition and operating conditions to enhance the dynamic performance of proton exchange membrane fuel cells garners significant attention. Although machine learning surrogate models are efficient for fuel cell analysis and optimization, the varied voltage dynamic response patterns (e.g., loading failure, voltage undershoot, and voltage hysteresis) challenge regression surrogate models designed for steady-state performance predictions. In response, this study introduces a joint framework combining classification and regression models for dynamic performance prediction. For training, a transient, two-phase, non-isothermal fuel cell model with integrated catalyst agglomerate is developed. The dynamic voltage deviation (${\sigma }_V$) is proposed as an index to characterize the dynamic performance of the fuel cell. This joint surrogate model achieves correlation coefficients of 0.9976 and 0.9961 for predicting ${\sigma }_V$ in training and test sets, respectively. Through this model, sensitivity analyses of the CCL composition and operating conditions are conducted to quantify their impact and interactions on the fuel cell's dynamic performance. Besides, the analysis reveals a trade-off between dynamic performance and steady-state output. To balance these, a multi-objective optimization is conducted. The results indicate that, compared to the base case, dynamic and steady-state performance improved by 44 % and 8 %, respectively.

Bioenergy is a water-intensive renewable energy and its upstream energy consumption and carbon emission during biomass planting, harvesting, collection, and transportation cannot be ignored. Biomass-based power systems necessarily have sustainable characteristics in energy, water, and carbon emissions. In this paper, a biomass-syngas-fueled solid oxide fuel cell system integrated gas turbine and organic Rankine cycle is designed. An exergy-based exergy-water-carbon-cost nexus method is developed to present the analysis of interactive relationships of the integrated system. The Sankey flows of cumulative exergy destruction, water footprint, and carbon footprint under the design working conditions are obtained and their corresponding intensities of the generated power are determined. The sensitivity analysis of biomass parameters, such as cumulative exergy, water footprint, and carbon footprint is implemented. The system exergy efficiency reaches 50.37 %. The accompanied cumulative exergy consumption to generate 1 kWh power exergy reaches 1.616 kWh. The water and carbon footprints of power are 63.59kg/kWh and 345.7 g CO₂-eq/kWh, respectively. Considering the exergy-water-carbon cost, exergy, water, and carbon account for 92.54 %, 0.63 %, and 6.83 % of total power cost, respectively.

Considered as one of the effective approaches to address the energy crisis and develop green and sustainable energy, the application of solar energy in multiple stages was investigated in this study. By designing a WS₂/ZnIn₂S₄ heterojunction, a multifunctional coupling system based on interfacial water evaporation technology was constructed. In this system, the water evaporation rate was 1.67 kgꞏm⁻²ꞏh⁻¹, and the photocatalytic degradation efficiency of rhodamine B reached 96.5 %. Moreover, the electric energy output from thermoelectric conversion was innovatively in situ applied for photocatalytic hydrogen production, which increased the photocatalytic hydrogen production efficiency by five times, with a hydrogen production rate of 40.3 μmolꞏcm⁻²ꞏh⁻¹. This study successfully integrated thermoelectric power generation, photocatalytic hydrogen production, and photocatalytic degradation of dye wastewater into an advanced solar-driven interface evaporation system, enabling the simultaneous conversion of solar energy into multiple forms of energy, improving solar energy utilization efficiency, which was of great significance for promoting the practical application of solar energy.

The co-combustion of sewage sludge and biomass has demonstrated significant potential for reducing carbon emissions and realizing the resource utilization of solid waste. In this study, the co-combustion behavior and pollutant emissions of sewage sludge and corncob were systematically investigated using thermogravimetric-Fourier transform infrared spectroscopy-mass spectrometry (TG-FTIR-MS) and a fixed-bed reactor. When the corncob blending ratio reached 30 %, the ignition temperature was 179.01 °C lower than that of sewage sludge, and the comprehensive combustion index increased by 13.92 times. The corncob in the mixed fuel dominated the volatiles' release and combustion process. The interaction strength increased as the corncob blending ratio increased. When the corncob blending ratio reached 70 %, it promoted the thermal weight loss process of sewage sludge. The release rate of CO₂ increased as the biomass ratio increased, and a 30 % corncob content could inhibit CO₂ emissions. Simultaneously, the interaction between sewage sludge and corncob inhibited the emissions of CO and NO during the co-combustion process, improving the combustion efficiency. This study provides theoretical support for developing the fuel value of sewage sludge, improving the amount of solid waste collaborative disposal, and realizing the leading carbon peak in thermal power industry.

The conversion of lignocellulose into valuable products is an area of interest to achieve sustainable development. Nowadays, the corn stover-ethanol biorefinery just produces lignin as a waste. However, lignin valorization can enhance profitability, improve resource utilization efficiency, and reduce carbon emissions. Thus, the objective of this work is to comprehensively evaluate the benefits of integrating lignin thermochemical conversion to generate bioproducts within ethanol biorefineries. Herein, 2000 metric tonne per day corn-stover biorefineries with various lignin utilization processes (combustion for power, pyrolysis to produce arenes, and gasification-syngas fermentation to produce ethanol) were modeled. Then, a comparative analysis was conducted across various dimensions of energy, environment, and economy (3E). The results suggest that integrating lignin valorization instead of combustion enhances carbon and energy recovery, as well as environmental and economic benefits. The minimum ethanol selling price has been estimated to be 834–873 $/t for various lignin utilization processes. Notably, lignin gasification-syngas fermentation demonstrates the best performance in all 3E metrics. However, related lignin thermochemical conversion processes still face high levels of uncertainty, necessitating further laboratory and pilot-scale research to improve technology readiness levels. This work is valuable for future advancements in the full conversion of lignocellulose into biofuels and chemicals.

To further investigate the hydrodynamic performance of a novel 10 MW semi-submersible floating offshore wind turbine (FOWT) OUCwind and the dynamic response of the FOWT, especially the high-frequency dynamic response induced by the high-order high-frequency hydrodynamic loads, an experimental study for OUCwind is carried out. A novel regular wave condition design method is proposed, i.e., making incidence wave periods that exactly meet an integer multiple of the natural period of the wind turbine, to stimulate the structural resonance of the tower. To determine the natural period of the wind turbine with an elastic boundary, an irregular wave test is carried out and the natural period of the wind turbine with the elastic boundary is proved to be 3 s. Different parts of the FOWT model are verified to satisfy the corresponding scale similarity through a series of validation tests. The hydrodynamic performance of OUCwind is investigated. Linear response is obtained by applying the band-pass filter to the total response. The pitch motions have apparent high-frequency components aligned with the natural frequency of the wind turbine under the environmental conditions with a wave periods of 6 s. For surge and heave motion, the linear component dominates these two responses and the effect of the high-frequency component on these two responses is negligible. The second-order doubling and third-order tripling wave effects have a tremendous impact on the tower-top shear force and mooring line tension. The experimental data providing high-frequency dynamic responses up to the quadruple order can be used for the validation and correction of mid-fidelity and high-fidelity numerical models. Finally, the mechanisms of the generation of the high-frequency dynamic response of the FOWT are also concluded in an illustrative form.

Pyrolysis of the pineapple waste biomass using an atmospheric pressure microwave plasma ensures satisfactory syngas production as a renewable energy source. The pineapple waste biomass samples used in the study were crowned and peeled in dry and wet conditions. The study used Taguchi experimental methods to find the optimum parameters for the experiment. Material mass was the most influential parameter, followed by input power, carrier gas flow, and material type. Increasing input power can reduce carbon dioxide emissions while increasing the production of carbon monoxide and hydrogen. The syngas production with 800 and 1000 W power peaked for 6 and 7 min, respectively, while the plasma with 1200 power peaked at 5 min. The wet pineapple waste sample with 1200 W had the highest syngas molar ratio (H₂/CO) output, the wet peel sample reached 4.18, and the wet crown sample reached 4.00. The dry sample had a lower ratio, with only 2.43 for the pineapple peel and 2.42 for the pineapple crown. The highest energy efficiency of biomass conversion is 72.59 %, achieved by a dry crown sample with 1000 W, followed by a dry crown sample with 1200 W power of 72.01 % efficiency. This finding shows that pineapple waste can be a viable feedstock in syngas production using an atmospheric pressure microwave plasma system with a rapid pyrolysis process and without catalyst added. It contributes to producing renewable energy and sustainable agricultural practices, reducing the environmental impact of conventional waste disposal methods, chemical costs, and carbon emissions to the environment.

N-doped porous biochar is considered as a promising carbon material for supercapacitor electrodes application. However, the intrinsic relations and effect mechanisms of the pore structure and N-doping to the capacitive performance are still inscrutable, giving rise to the challenges for enhancing the capacitive performance by regulating the physicochemical properties of N-doped biochar. In this study, various machine learning models were established to predict the specific capacitance of N-doped biochar electrodes based on the pore structure and N-doping properties. The effect mechanisms of pore structure and N-doping to the specific capacitance were also explored. Results showed that Random Forest model predicted the specific capacitance most accurately. The generalization performance of the model was verified to be quite well with our experiments. It is suggested that developing pore structure with abundant micropores plays more important role than N-doping in enhancing the specific capacitance. The optimal interval of each physiochemical property of N-doped biochar were also determined to maximize the specific capacitance. Furthermore, synergistic effects of pore structure and N-doping to the specific capacitance were revealed. This study provides a useful guideline for N-doped porous biochar production with the aim of capacitive performance enhancement.

Accurately measuring and analyzing the effective thermal conductivity of metal hydride beds is critical to design the structure of solid-state hydrogen storage tanks. On the basis of the steady-state radial heat flow method, a measurement cell of effective thermal conductivity was manufactured. The effective thermal conductivities of nonactivated and activated LaNi₅ powder beds were measured in helium, nitrogen, and argon atmospheres with the temperature changing from 20 to 60 °C and pressure from 0.1 to 4.0 MPa. Then, the effective thermal conductivities were further analyzed using the Zehner–Schlünder–Damköhler model. Results show that the effective thermal conductivities can be enhanced by increasing gas thermal conductivity, gas pressure, and bed temperature. In addition, the effective thermal conductivities can be accurately predicted using the modified Zehner–Schlünder–Damköhler model considering the Smoluchowski effect (error < ± 5 %). With the use of the modified Zehner–Schlünder–Damköhler model, the contributions of different heat transfer pathways to the entire heat transfer of LaNi₅ powder beds were analyzed. Approximately 70 %–91 % of the effective thermal conductivity of LaNi₅ powder beds is contributed by the conduction of the particle–gas–particle pathway.