In practical engineering, electro-osmotic treatment of large-scale silt projects will cause a lot of electricity waste.Some scholars have made an electro-osmotic method to treat silt and combine pile-loading to reduce the energy consumption of electric energy.In this paper, the effects of electro-osmotic treatment combined with pile-loading experiment on the consolidation of municipal sludge and the content of heavy metals in the sludge before and after electro-osmosis are analyzed and the conclusions are drawn.(1)Thecombination of electro-osmotic method and pile-loading experiment has strong capacity of drainage consolidation.(2)Thecontents of copper and zinc decreased obviously, and the electro-osmotic method combined with pile-loading method had a certain effect on the treatment of heavy metals in silt.
Considering rotation-induced centrifugal stiffening, spin softening, and Coriolis effects, the three-dimensional finite element model of a rotating blade with a dovetail structure is built through the contact dynamics theory. The fixed-interface component mode synthesis method is then adopted to reduce the model for high computational efficiency and adequate model accuracy. The effects of the number of normal modes on the first-six-order modal characteristics of the model varying with the rotating speed are studied between the reduced and full models. Next, the influence of rotating speed and friction factor on the nonlinear dynamic characteristics of the model under the action of aerodynamic force are elaborately discussed. The results show that: (1) tenon-mortise joint contact-induced nonlinearity under low rotating speeds results in the intermittent interference of contact surfaces and frequency multiplications of aerodynamic excitation frequency in the spectrum cascades, while that under high rotating speeds causes the continuous interface contact and asynchronous excitation at the tenon-mortise joint; (2) the increase of friction factor results in a lower contact pressure distribution and the right shift of the resonance peak (i.e., hard nonlinearity).
Abstract The intensification of carbon emissions and the energy crisis have made the safe and reliable application of renewable energy in the energy supply system significantly urgent. Liquid air energy storage (LAES) system is an effective means to solve the time and space mismatch between energy supply and demand. The LAES has the advantages of no geographical restrictions, high energy storage density and flexible operation, making it available to integrate with other industrial processes. In traditional LAES, the heat generated in the compression process is used to supplement the heat in the expansion process, and the excess heat is dissipated. In this study, the compressor inlet air is cooled by absorption refrigeration cycle to avoid excess compression heat, which reduces the power consumption of the compressor and improves the efficiency of the system. The sensitivity analysis of the ambient temperature and the compressor stages on the system efficiency is performed. Furthermore, a comparative analysis between the absorption refrigeration cycle driven by the waste heat and the compression refrigeration cycle driven by electricity for air precooling of the compressor inlet was carried out, and the system round-trip efficiency, exergy efficiency and initial investment cost was selected as indicators for system evaluation.
Abstract Liquid air energy storage (LAES) is one of the most recent technologies introduced for grid-scale energy storage. The cryogenic regenerator, which can greatly affect the system efficiency, is the key component of the system. A non-ideal packed bed regenerator for the LAES system was investigated. The cold energy loss and the axial heat conduction of the packed bed regenerator exist in the intermittent period between the charging and discharging process, which significantly degrades the system performance. With rock particles used as the cold energy storage medium, the axial temperature distributions of the packed bed regenerator with different initial temperatures and intermittent periods were compared. Also, the cold energy loss with different boundary conditions was analysed. The results show that the intermittent period exacerbates the negative impact of the axial heat conduction on the performance of the packed bed, and the thickness of the thermocline decreases as the inlet temperature of the cold end decreases. Moreover, as the cold energy loss increases, the cold energy storage efficiency of the packed bed decreases significantly.
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