《International Journal of Hydrogen Energy》2023,48(52):19846-19861

On Flores island (Azores, Portugal), energy production depends up to 47% on fossil fuels, namely Diesel. To minimize CO₂ emissions, the dependency on fuel prices, and to mitigate the consequences of variability and intermittency of renewable energy sources, a new energy system, based on H₂ storage was analysed. To achieve the optimal size of the system, a computer model was developed and a multi-objective genetic algorithm function was used to minimize three objectives: the difference of levelised cost of energy (△LCOE), CO₂ emissions and the percentage of renewable energy dumped (R_{RES, dump}). From the set of solutions obtained, one that meets R_{RES, dump} ≤ 1%, lowest CO₂ emissions and lowest △LCOE is chosen and an economical and energetic analysis is performed. The newly proposed system reduces Diesel consumption by 68,7% (1057487 L/year) and CO₂ emissions by 65,9% (2455,1 CO₂ tons/year) achieving a renewable energy sources (RES) penetration of 89% (36% increase), but fails to decrease the levelised cost of energy (56,62 €/MWh increase). However, a way to make the project viable through financial support is presented and an alternative to reduce the levelised cost of energy by commercialising the products of electrolysis, hydrogen and oxygen, is proposed. Finally, it is expected that with further research and development of H₂ technologies, economic and energetic results will get more advantageous, opening up new perspectives for the future.  相似文献   

    

《International Journal of Hydrogen Energy》2023,48(63):24242-24254

In this research study, orange peel-based biocatalysts developed from different acid protonation were used as a metal-free catalyst for hydrogen production from sodium borohydride (NaBH₄). In order to prepare the orange peel-based biocatalyst with higher catalytic activity, experiments were conducted with pure orange peel, different acid molar concentrations, and calcination temperatures. The physical morphology, surface texture, and chemical interaction were thoroughly analyzed by XRD, FTIR Raman, FESEM, BET, and TGA. As a result of the experiment, it was determined that the highly acid-treated biocatalyst (40% H₃PO₄, 40% H₂SO₄, 40% HCl) and calcinated at 450 °C for 1 h had higher catalytic activity. As a result, bio-hydrogen production at 35 °C and 70 °C methanolysis with 3% NaBH₄ catalyzed by a mixture of acid-treated catalysts were found as 46,213 and 63,842 ml min⁻¹g.cat⁻¹, respectively. However, with the increase of molar concentration of biocatalyst with 40% individual acid prolonged samples, the HGR rates will not have a satisfactory value in comparison with the 40% mixture of the acid-treated catalyst due to less number of active sites.  相似文献   

    

《International Journal of Hydrogen Energy》2023,48(35):12982-12999

This work aims at developing an approach for modelling and optimizing the operation of a reference alkaline electrolysis unit operating in transient state using orthogonal collocation on finite elements (OCFE). The main goal is to define the set of operating conditions that minimize the processing cost (associated to electricity cost) given a hydrogen yield. Three components of the electrolyzer are considered: the stack of electrolytic cells and two separators that single out the hydrogen and oxygen gas streams. The dynamic behavior is considered for the mass holdup in the separators as well as the energy accumulation for these three components. The associated mathematical model is derived in the paper. Its solving allows characterizing the influence of the transient operating parameters of the system on its working and associated final hydrogen production. Mathematical optimization aims at defining the ideal operating load in order to minimize costs associated to fluctuating price of electricity consumed by the stack given a defined hydrogen yield. The model has been validated according to experimental test runs and operating conditions have been optimized under a proof of concept scenario saving 17% of electricity costs if compared to constant plant capacity.  相似文献   

    

《ISA transactions》2018

Electric machines and drives have enjoyed extensive applications in the field of electric vehicles (e.g., electric ships, boats, cars, and underwater vessels) due to their ease of scalability and wide range of operating conditions. This stems from their ability to generate the desired torque and power levels for propulsion under various external load conditions. However, as with the most electrical systems, the electric drives are prone to component failures that can degrade their performance, reduce the efficiency, and require expensive maintenance. Therefore, for safe and reliable operation of electric vehicles, there is a need for automated early diagnostics of critical failures such as broken rotor bars and electrical phase failures.In this regard, this paper presents a fault diagnosis methodology for electric drives in electric ships. This methodology utilizes the two-dimensional, i.e. scale-shift, wavelet transform of the sensor data to filter optimal information-rich regions which can enhance the diagnosis accuracy as well as reduce the computational complexity of the classifier. The methodology was tested on sensor data generated from an experimentally validated simulation model of electric drives under various cruising speed conditions. The results in comparison with other existing techniques show a high correct classification rate with low false alarm and miss detection rates.  相似文献   

    

《Utilities Policy》2018

Natural gas utilities in New England face increasing natural gas transmission system congestion and volatile spot gas prices. We observe that prevailing evaluation methods for natural gas efficiency programs value avoided firm pipeline capacity based on its total (‘gross') cost. We propose, consistent with deregulated electricity markets, to value avoided firm pipeline capacity at its ‘net’ cost. Specifically, we account for revenues associated with selling excess capacity during periods when the firm capacity holder does not fully utilize its rights. Our evaluation of commercial building efficiency programs suggests that prevailing evaluation methods could over-estimate the value of efficiency programs when those programs are intended to offset new capacity investments (i.e., the utility is in need of additional firm capacity). The situation is more complex for a utility with sufficient firm pipeline capacity to meet forecast load (i.e., consumption). In this case, the prevailing evaluation methods have the potential to under- or over-estimate the value of efficiency programs. The value of avoided infrastructure investments is likely to vary with the specific circumstances of the utility and the expected revenues associated with short-term sales enabled by available capacity. In the future, we recommend that economic regulators of natural gas distribution utilities, the state public utility commissions (PUCs), value avoided infrastructure investments at the ‘net' cost of the investment instead of the ‘gross' cost.  相似文献   

    

《Advanced Powder Technology》2020,31(8):3507-3520

This paper presents a scale-up procedure of parameter estimation in the selection function and breakage function from single particle impact breakage to inform the predictions at the process scale of an impact pin mill. The selection and breakage functions used in population balance model (PBM) for particle breakage in the literature are briefly reviewed. Single particle breakage tests are conducted in a vertical impact tester subject to varying impact velocities. The single particle breakage results further serve to provide the database for the parameter estimation in Vogel and Peukert model (Vogel and Peukert, 2005). The estimated parameters in the particle level are upscaled in an impact pin mill using the population balance model, which is implemented in the software gPROMS (Process Systems Enterprise, UK) (gPROMS® 4.1 Release Notes, 2016). The impact milling tests were carried out in an impact pin mill UPZ100 subject to four feed rates, providing the dataset for model validation. The sensitivity analysis of the PBM parameters was conducted to help identify their leverage on the particle size distribution. The scale-up procedure by specifying the parameters from single particle level to the process level of PBM demonstrates an approach to help predict the size reduction process subject to the prevailing mechanism in an impact pin mill and other milling processes alike.  相似文献   

    

《International Journal of Hydrogen Energy》2020,45(7):4821-4828

A new catalyst promoting an overall anodic oxidation reaction is suggested. In this catalytic structure, glucose oxidase (GOx) is immobilized onto polyethyleneimine (PEI) and carbon nanotube (CNT) (CNT/PEI/GOx) before polymerized methyl red (PMR) mediator coupled with PEI is further entrapped onto the CNT/PEI/GOx to complete CNT/PEI/GOx/[PEI-PMR]. With this, entrapped mediator-based electron transfer is well established. According to the related characterizations, when the glucose is used as reactant, overall oxidation reactions including glucose oxidation reaction are significantly improved by synergetic effect between GOx as a catalyst and PMR as an entrapped mediator. The optimal amount of embedded PMR determines the overall oxidation reaction rate because the amount of PMR that is obtained from the methyl red (MR) concentration of 3 mg mL⁻¹ can maximize the electron shuttling effect between GOx and electrode, followed by the overall oxidation reaction rate. Based on this, it is shown that CNT/PEI/GOx/[PEI-PMR3] is the best catalytic structure for promoting the overall oxidation reaction.  相似文献   

    

《International Journal of Hydrogen Energy》2020,45(24):13387-13397

Long-lasting charge/discharge cycling (−0.5C/+0.5C) of a super-stoichiometric hydrogen storage alloy with LaNi_4.5Co_0.5Al_0.32Sn_0.34Zn_0.10 composition has been carried out in a 6 M KOH solution to evaluate the role of selective dissolution of amphoteric elements (Al, Sn and Zn) in electrochemical hydrogenation properties and corrosion behaviour of the hydride electrode. Among alloy constituents, leaching efficiency is the most evident for Sn and Zn additions. Rates of Ni and Co leaching are 2 orders of magnitude lower whereas La is not leached at all. Selective leaching of Al, Sn and Zn is prone to improved material activation and has a minor effect on material passivation and capacity fade. Selective leaching of amphoteric elements as a result of alkaline cycling follows a first-order chemical kinetics law.  相似文献   

    

《International Journal of Hydrogen Energy》2020,45(38):19691-19706

The cold energy in many liquefied natural gas (LNG) satellite stations is directly carried away by air or seawater. This causes cold energy waste and environmental cold pollution. To solve this problem, a combined power, heating and cooling system (CCHP) driven by LNG is established based on solid oxide fuel cell (SOFC) and humid air turbine (HAT), namely SOFC-HAT-CCHP system, in which, not only can the waste cold energy cool compressor inlet air to decrease power consumption, but supply cold energy for the cold storage and CO₂ recovery. Based on FORTRAN and Aspen Plus, the thermodynamic performance calculation models and the simulation work of the new system are carried out, such as the exergy and energy analysis, as well as the effects of the selected important variables. The results indicate that total exergy efficiency and total power efficiency are 64.7% and 54.4%, and the total thermal efficiency is 79.1%. Besides, the capture rate and purity of the CO₂ are 98.7% and 98.9% respectively. The novel system is environmental protective, energy-saving and efficient, which may provide a new direction to reasonably utilize the waste cold energy in LNG satellite stations.  相似文献   

    

《Fuel Cells Bulletin》2020,2020(3):9-10

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