Search results for "Fuel Technology"
showing 10 items of 323 documents
POSS-Al-porphyrin-imidazolium cross-linked network as catalytic bifunctional platform for the conversion of CO2 with epoxides
2023
Two heterogeneous catalysts were prepared with the aim of following the promising path of CO2 fixation into epoxides. The synthetic procedure involves a radical copolymerization of an octavinylsilsesquioxane as inorganic core building block and tetrastyrylporphyrin aluminum chloride monomer (TSP-AlCl) in presence (POSS-TSP-AlCl-imiBr) or in absence (POSS-TSP-AlCl) of a bis-vinylimidazolium bromide salt (bis-imiBr), in order to investigate if the bifunctional heterogeneous material can display better catalytic performance than the separate species. All the solids were fully characterized and tested in the synthesis of cyclic carbonates starting from CO2 and several epoxides. The synergic coo…
Exergy analysis of electrodialysis for water desalination: Influence of irreversibility sources
2022
The increasing freshwater demand is pushing the development and adoption of desalination technologies. In this framework, electrodialysis has a consolidated role in brackish water desalination, but to make it competitive with other technologies for the desalination of more concentrated solutions (e.g., seawater), the specific energy consumption should be reduced. Exergy analysis provides a useful tool for determining the contribution of each thermodynamic inefficiencies on the process efficiency and the specific energy consumption. In this regard, this paper presents an exergy analysis of the electrodialysis process. A 1-D model is used for evaluating the performance of industrial-scale sys…
Simplified models for the performance evaluation of desiccant wheel dehumidification
2002
In the present communication, simple models have been presented to evaluate the performance of rotary desiccant wheels based on different kind of solid desiccants e.g. silica gel and LiCl. The first part of the paper presents ‘Model 54’ which is developed for silica gel desiccant rotor. The model has been derived from the interpolation of experimental data obtained from the industry and the correlations have been developed for predicting outlet temperature and absolute humidity. The ‘Model 54’ consists of 54 coefficients corresponding to each correlation for outlet absolute humidity and temperature and it is found that the model predicts very well the performance of silica gel desiccant rot…
Update on desiccant wheel model
2004
This short communication presents the update on the desiccant wheel models, developed earlier by the present authors. It is to be mentioned here that the psycrometric model presented earlier (Int. J. Energy Res., 2003; 27:17) is valid only for the desiccant wheel running with identical volume air-flows in supply and regeneration sides. However, when system runs with volume air flow ratio between supply and regeneration side (α), different from 1 (one), the model need further modifications. In the present work, correction factors were developed and incorporated in order to update the earlier model for predicting correctly the temperature and humidity of processed air at the outlet of desicca…
An experimental investigation on the poor hydrogen sorption properties of nano-structured LaNi5 prepared by ball-milling
2011
Abstract Nano-structured LaNi5 hydrogen storage materials prepared by ball-milling is analysed using differential scanning calorimetry (DSC) and x-ray photoelectron spectroscopy (XPS). DSC results indicate a partial elimination of defects at 500 °C in a more efficient way for the short-time ball-milled powders compared to the long-time ball-milled ones. XPS results show almost no change in the core-level electronic structure for La and Ni of LaNi5 in the bulk and the nano-structured forms, but gives an indication that the self-restoring mechanism of the active surface observed in the bulk sample (Siegmann et al. Phys. Rev. Lett. 40, 972) may not be occurring in the nano-powders. Results fro…
Sensitivity analysis and process optimization of a natural gas dehydration unit using triethylene glycol
2019
Abstract Dehydration of natural gas by absorption using triethylene glycol (TEG) is a common industrial offshore procedure to ensure the compliance with the required water dew point specifications for midstream transportation. Two thermodynamic models, the UMR-PRU and the TST/NRTL, are applied for the process simulation while a preliminary economic evaluation has been conducted revealing that both yield overall similar results as for the fixed capital cost which is found to be in good agreement with reported literature values. Moreover, sensitivity analysis of several operational parameters of the process has been performed and optimized values are suggested aiming to reduce its energy requ…
Stability analysis of load frequency control for power systems with interval time-varying delays
2023
This study investigates the stability problem of load frequency control (LFC) for power systems with interval time-varying delays. The two categories of time delays, the lower bound being zero and non-zero, are considered. The systems can be described as time delay systems of load disturbances. First, an augmented Lyapunov–Krasovskii functional (LKF) is constructed. Some delay-dependent nonintegral terms and single integral terms are additionally introduced to make full use of the information on the system state variables and the time-varying delays. Second, to overcome the problem of nonlinear inequalities caused by the augmented LKF, the nonlinear inequalities are converted into linear ma…
Computational Screening of Doped Graphene Electrodes for Alkaline CO2 Reduction
2020
The electrocatalytic CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR) is considered as one of the most promising approaches to synthesizing carbonaceous fuels and chemicals without utilizing fossil resources. However, current technologies are still in the early phase focusing primarily on identifying optimal electrode materials and reaction conditions. Doped graphene-based materials are among the best CO<sub>2</sub>RR electrocatalysts and in the present work we have performed a computational screening study to identify suitable graphene catalysts for CO<sub>2</sub>RR to CO under alkaline conditions. Several types of modified-graphene frame…
Experimental analysis of materials in proton exchange membrane electrolysis cells
2019
Abstract An accelerated supply and demand of energy has resulted in an increased need for efficient energy storage options, where storing energy in hydrogen gas emerges as one of the most attractive. In this study, a singular proton exchange membrane (PEM) electrolysis cell was designed using adequately low-cost materials, and tested using polarisation curves, cyclic voltammetry and AC impedance. A comparative study of various micro porous layer (MPL) materials was performed in an effort to find suitable options which are able to steadily operate under anodic conditions. The best performance was achieved using carbon cloth, however this material was unstable. Untreated porous titanium and n…
Effect of coatings on long term behaviour of a commercial stainless steel for solid oxide electrolyser cell interconnect application in H2 /H2O atmos…
2014
Abstract K41X (AISI 441) stainless steel evidenced a high electrical conductivity after 3000 h ageing in H 2 /H 2 O side when used as interconnect for solid oxide electrolyser cells (SOEC) working at 800 °C. Perovskite (La 1 − x Sr x MnO 3 − δ ) and spinel (Co 3 O 4 ) oxides coatings were applied on the surface of the ferritic steel for ageing at 800 °C for 3000 h. Both coatings improved the behaviour of the steel and give interesting opportunities to use the K41X steel as interconnect for hydrogen production via high temperature steam electrolysis. Co 3 O 4 reduced into Co leading to a very good Area Specific Resistance (ASR) parameter, 0.038 Ω cm 2 . Despite a good ASR (0.06 Ω cm 2 ), La …