Institutional Repository of GuangZhou Institute of Energy Conversion, CAS
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Cobalt Nanoparticles Catalyzed <i>N</i>-Heterocycles Synthesis <i>via</i> Acceptorless Dehydrogenative Coupling
No full textThe acceptorless dehydrogenation reaction is a sustainable and atom-economical methodology in organic synthesis, resulting in the byproducts of only hydrogen or water. Herein, a robust Co-Si/CN catalyst (derived from ZIF@SiO2 composite) has been synthesized through a one-step assembly process via pyrolysis and etching. This catalyst has been employed for the acceptorless dehydrogenative coupling of 2-aminoalcohols with secondary alcohols, enabling efficient conversion of various substrates into desired quinoline or pyridine derivatives with a yield of up to 94 %
Two-Phase Relative Permeability Curves of Bingham Heavy Oil Under Different Types of Wettability: A Theoretical Model
No full textAs an important and universal petrophysics of heavy oil reservoirs, the two-phase flow ability inside porous medium is vital for heavy oil development. Utilizing the laminar flow theory and an ideal pore structure, especially cylinder model, the function of the relative permeability of heavy oil-water with water saturation is derived by incorporating the principles of momentum conservation and the characteristics of Bingham fluids, which was modified by validated experiment. Two-phase relative permeability, considering heavy oil as non-Newtonian fluid, is the function of water saturation, pore size, oil-water viscosity ratio, and yield stress. The results of the validated experiment show that the theoretical values calculated employing the modified equation exhibit better agreement with the experimental values, particularly when the viscosities of two-phase fluid are great. The results of the modified two-phase relative permeability show a decrease in water saturation interval corresponding to the two-phase flow area and a smaller value of permeability at equal two-phase relative permeability. The oil-water viscosity ratio in the hydrophobic pores affects the water-phase relative permeability, although the magnitude of its influence diminishes as the viscosity ratio increases. The behavior of relative permeability in hydrophilic pores is the opposite of that in hydrophobic pores. This work can afford good application prospects for mobility control in multilayered reservoirs through the heterogeneous-phase-composite fluid. The saturations of the remaining oil and irreducible water also play a vital role in the prediction of permeability. The work can afford good application prospects for the flow behavior of Bingham heavy oil in pores with different types of wettability
Effect of CO<sub>2</sub> Thickeners on CH<sub>4</sub>-CO<sub>2</sub> Replacement in Hydrate-Bearing Sediment
No full textCO2 fracturing is known as the best solution to improve the efficiency of the CO2 replacement of natural gas hydrates, but the effect of CO2 thickeners on CH4-CO2 replacement are barely noticed. In this work, the effect of four kinds of CO2 thickener-including DL-Lactic acid, polyvinyl acetate, ethyl trifluoroacetate and octamethyl trisiloxane-on the CH4-CO2 replacement in quartz sand was measured thermodynamically and kinetically. The results show that the majority of the CO2 thickeners had no effect on the equilibria of the CH4 and CO2 hydrates, except for DL-Lactic acid, where the temperature depression caused by the addition of 5.5 wt% DL-Lactic acid was about 0.52 and 0.48 K for the CH4 and CO2 hydrates, respectively. In the kinetic measurements, the CH4-CO2 replacement was promoted via the addition of the CO2 thickeners, except DL-Lactic acid. The CO2 thickeners were suggested to strengthen the CH4-CO2 replacement by enhancing the gas exchange in the pore space. Octamethyl trisiloxane, which could promote CH4 recovery and CO2 capture at a low concentration, was suggested to be an ideal CO2 thickener for CH4-CO2 replacement
Parametric analysis of a fully coupled USV-type wave energy converter: An approach based on wave-to-grid modelling
No full textThe integration of the wave energy converter and the unmanned surface vehicle (USV), which has the power generation capability and the mobile capability, is attracting increasing attention in concept design, control, and parametric study, as the integrated system can play a crucial role in the maritime sectors of commerce, science, and military. Enhancing the power generation of a USV-integrated wave energy converter contributes to prolonged USV operations or grid supply, but the power generation performance of this new-type device is significantly influenced by its various coupled subsystems, which requires a systematic methodology for distinguishing key design parameters. To address that problem, a comprehensive wave-to-grid model that reflects all subsystem coupling, energy losses, and constraints is developed to comprehensively describe system dynamics, and then a Taguchi method is employed to investigate the influence of selected design parameters on electric power generation. Results reveal that the piston area of the hydraulic cylinder and the accumulator pressure are the two most influential parameters affecting the time-averaged electric power of the proposed USV-type wave energy converter. The proposed methodology provides guidelines for technicians on how to design wave energy converters optimally
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