The dispatching optimization of power grid is to obtain the greatest benefits on the basis of safe and stable operation of the power grid, which is of great significance for the energy-saving, reliability of the power...
The dispatching optimization of power grid is to obtain the greatest benefits on the basis of safe and stable operation of the power grid, which is of great significance for the energy-saving, reliability of the power grid. Therefore, a multi-objective model of power grid dispatching which considers the heat-power coupling characteristics of CHP units is developed in this study. The economic benefit and minimum wind power abandonment are taken as optimizing targets in the model. Meanwhile, the detail operation characteristics of condensing power plants and CHP units are considered in this model based on off-design models of power plant. Besides, the regional heat load and power load are scheduled together. Finally, the AHP-entropy method is used to obtain the weights of the two optimizing targets of economic benefit and wind power abandonment, and the multi-objective is converted into a single-objective.
Hydrogen (H 2 ) is a clean and environmentally friendly energy carrier. The depletion of fossil fuels makes renewable H 2 production highly desirable. Water reforming of renewable biomass to hydrogen, with a relay of ...
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Hydrogen (H 2 ) is a clean and environmentally friendly energy carrier. The depletion of fossil fuels makes renewable H 2 production highly desirable. Water reforming of renewable biomass to hydrogen, with a relay of natural photosynthesis to biomass, would be an indirect pathway to realize the ideal but extremely challenging photocatalytic overall water splitting to hydrogen, with favorable thermodynamics. Since the seminal work of water reforming of biomass in 1980, great endeavors have been made. Nevertheless, hitherto, the entire kinetic pathway has been elusive, which seriously limits the reforming processes. Using a designed well-organized redox-neutral cleavage of C−C, O−H and C−H bonds enabled by photoelectrocatalysis, here, we show the efficient water reforming of biomass to hydrogen at room temperature, with a yield up to 93 %. The clear insights into the kinetic pathway with oxidation of carbon radicals to carbon cations as the indicated rate-determining step, would cast brightness for efficient and sustainable hydrogen production to accelerate the hydrogen economy.
The influences of the preset angle on the dynamic responses of the typical airfoil section with cubic nonlinear stiffness were investigated under consideration of the aerodynamic flutter onset due to certain angle of ...
The influences of the preset angle on the dynamic responses of the typical airfoil section with cubic nonlinear stiffness were investigated under consideration of the aerodynamic flutter onset due to certain angle of attack. The typical airfoil model with cubic nonlinear stiffness is developed to analyze the plunging and the pitching motions for the airfoil section. Based on the Grossman’s quasi steady aerodynamic model, the aerodynamic lift and the moment can be obtained and then the equation of motion for the airfoil section is derived by applying the Lagrange theorem. The effects of the preset angle and the oncoming flow speed on the nonlinear dynamics are analyzed by means of the bifurcation diagram, the frequency-amplitude diagram, the time history, etc. Simulation results show that the preset angle influences the intensity of the vibration, moderate or severe, stable or unstable, even under certain circumstance, the jump and chaos phenomenon occur; and the oncoming flow speed affects the distribution of the vibration energy for the plunging and the pitching motions. The unstable stall region for the responding parameters should be avoided to keep the airfoil safe in engineering practice. Some qualitative and quantitative rules are obtained for the airfoil design and the flutter suppression.
Advancing catalyst design is pivotal for the enhancement of photocatalytic processes in renewable energy conversion. The incorporation of structural chirality into conventional inorganic solar hydrogen nanocatalysts p...
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Advancing catalyst design is pivotal for the enhancement of photocatalytic processes in renewable energy conversion. The incorporation of structural chirality into conventional inorganic solar hydrogen nanocatalysts promises a significant transformation in catalysis, a feature absent in this field. Here we unveil the unexplored potential of geometric chirality by creating a chiral composite that integrates geometric chiral Au nanoparticles (NPs) with two-dimensional C 3 N 4 nanosheets, significantly boosting photocatalytic H 2 evolution beyond the achiral counterparts. The superior performance is driven by the geometric chirality of Au NPs, which facilitates efficient charge carrier separation through the favorable C 3 N 4 -chiral Au NP interface and chiral induced spin polarization, and exploits high-activity facets within the concave surfaces of chiral Au NPs. The resulting synergistic effect leads to a remarkable increase in photocatalytic H 2 evolution, with an apparent quantum yield of 44.64 % at 400 nm. Furthermore, we explore the selective polarized photo-induced carrier separation behavior, revealing a distinct chiral-dependent photocatalytic HER performance. Our work advances the design and utilization of chiral inorganic nanostructures for superior performance in energy conversion processes.
To enhance knowledge about efficiency improvement and reactor optimization in supercritical water gasification,an experimental system was designed to study the pressure and temperature distribution of subcritical and ...
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To enhance knowledge about efficiency improvement and reactor optimization in supercritical water gasification,an experimental system was designed to study the pressure and temperature distribution of subcritical and supercritical water in a channel,representing a simplified continuous *** pressure drop and temperature distribution along and perpendicular to the forced flow are studied by the measure points inserted inside the test *** results show that the pressure drop in the test section is linearly negatively correlated with the average enthalpy of the inlet and outlet,eventually reaching negative values(-0.177 MPa)at high average enthalpy(2300 kJ kg^(-1)).Temperature and specific enthalpy along the flow direction match theoretical estimates,except near the pseudocritical *** subcritical cases,horizontal temperature differences are positively correlated with enthalpy differences and mass flow rates but remain nearly constant in supercritical ***,with fluid temperature rising from the pseudocritical point,the horizontal temperature difference first increases,then decreases,and reaching a peak of 4.29 K at a fluid temperature of 664 *** of the obtained data reveals that the negative correlation and values of the pressure drop are caused by fluid volume ***,fluid volume expansion,near-wall natural convection,and turbulent forced flow fluctuations contribute to horizontal temperature non-uniformity.
The use of carbon nitride-based materials and light to drive catalytic water splitting has enormous potential for the production of hydrogen. Revealing the processes of molecular conjugation, nucleation, and crystalli...
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Organic Rankine cycle (ORC) which recovers waste heat in the temperature range of 80°C-140°C was investigated. Exergy efficiencies of various components and ORC system were paid great attention. The working ...
Organic Rankine cycle (ORC) which recovers waste heat in the temperature range of 80°C-140°C was investigated. Exergy efficiencies of various components and ORC system were paid great attention. The working fluids of R245fa and R600a are used. It is found that, for saturated ORCs, the expander inlet temperature has the optimum value, so the system exergy efficiency is maximum. With the increase of heat source temperature, the optimal inlet temperature of the expander is also increased. And also for saturated ORCs, the exergy efficiencies of evaporator and expander are highest efficiency, when evaporator exergy efficiency is increased with increase of heat source temperatures, the expander exergy efficiency is unchanged. The condenser decreased exergy efficiencies by increasing the heat source temperatures.
This research focuses on the preparation and properties of rice hull ash(RHA). We prepared RHA from combustion of rice husk in the fluidized-bed reactor. The temperature field of the furnace was steady and bellow 850&...
This research focuses on the preparation and properties of rice hull ash(RHA). We prepared RHA from combustion of rice husk in the fluidized-bed reactor. The temperature field of the furnace was steady and bellow 850°C to keep SiO2 amorphous. XRD, BET and SEM were applied in the characterization tests to investigate the effect of flow rate(u), the higher primary-secondary wind ratio(i) and relative height of bed material. The optimal combustion condition for preparing RHA was discussed. RHA obtained from rice hull contains abundant amorphous SiO2 (>90%) and the characterization results of RHA show its potential to be a good catalyst supporter.
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