Review on treatment technology of salt wastewater in coal chemical industry of China

A systematic review of supercritical carbon dioxide(S-CO2) power cycle for energy industries: Technologies, key issues, and potential prospects

Distributed solar desalination by membrane distillation: current status and future perspectives.

As policies have been implemented globally to limit the production of greenhouse gases (GHGs) and the effects of climate change, the generation of electricity by renewable technologies has started to increase. The development of sustainable energy storage solutions has also become more important. The continued use of conventional chemical batteries presents environmental issues such as heavy metal pollution and the use of unsustainable resources. An environmental Life Cycle Assessment (LCA) has been conducted to analyse the environmental impact of an innovative Thermal Battery (TB) and was compared with the impact of a Lithium Iron Phosphate Battery (LIPB) using a “cradle-to-gate” approach to establish the system boundaries. The study used the findings from existing literature to determine the environmental impact of the LIPB. The life cycle inventory for the TB was constructed based on a model and available literature. In this regard, the two products were compared on 10 impact categories, and the results indicated that the TB performed better in 8 categories on average. The highest impact observed from the TB was in terrestrial ecotoxicity, where it emitted above 7000 times more than the LIPB, amounting to approximately 0.0153 after normalisation. The highest normalised environmental load in the study was indicated to be in the category of marine ecotoxicity by the LIPB at 0.27, which was significantly higher than any load for the TB. Overall, the results obtained are encouraging for the TB, but it is recommended that a field study is completed to verify the assumptions made in this paper and to achieve a better comparability with studies conducted similarly.

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Comparative environmental life cycle assessment of conventional energy storage system and innovative thermal energy storage system

Multi-objective optimization of guide vanes for axial flow cyclone using CFD, SVM, and NSGA II algorithm

In recent years, renewable energy, particularly solar energy and wind energy, has demonstrated robust growth worldwide. However, the intermittent nature of these energy sources causes significant challenges for the security and reliability of grid, which limits the penetration growth in power market. To enable a higher penetration of renewable energy sources and satisfy the demand for peak shaving and valley filling of the grid, one possibility is to couple them with energy storage systems. In this study, two supercritical compressed carbon dioxide energy storage systems coupled with concentrating solar thermal storage are proposed. One is a simple compression cycle, and the other is a split compression cycle. Both thermodynamic and economic performance have been investigated numerically. The effects of energy storage pressure, heating temperature, thermal oil mass flow rate and split ratio are discussed. The results indicate that under the designed condition, there exists a maximum energy storage efficiency for the simple cycle when the heating temperature is lower than 538.15K. Continuing to increase heating temperature, the efficiency first increases from 64% to 73.9% rapidly as the total pressure ratio rises from 3 to 5. However, the improvement of it will be limited after the pressure ratio exceeds 5. Besides, if the thermal oil mass flow rate rises, the efficiency also has a maximum value, which appears between 150kg/s and 160kg/s. Finally, for the split cycle, there exists an optimal value. And the optimal condition can promote the Dynamic Payback Period and Levelized Cost of Energy to fall about 2 years and 6.1% compared to the simple cycle.

Thermodynamic and Economic Assessment on the Supercritical Compressed Carbon Dioxide Energy Storage System coupled with Solar Thermal Storage

In order to improve the performance of the separation device, a novel kind of cyclone separator is designed. The effects of the structure parameters and operation parameters on pressure drop and separation efficiency are investigated based on orthogonal experimental through the test platform. In addition, the internal flow characteristics in the optimized swirl generator are investigated by numerical simulation. Accordingly, the pressure drop of the optimized swirl generator is 170.9 Pa and its separation efficiency is 68.23% when extraction ratio is 5%. The blade shape and the blade outlet angle can influence the pressure drop and efficiency. The diameter of guiding cone has influence on pressure drop, but has no influence on the efficiency. When the extraction ratio is increased to 10%, the efficiency could be raised to 79.97%, and it has no significant increase at higher extraction ratio. The separation efficiency can reach to 88.10% when it is used to separate 180–250 u m sand. Finally, the simulation reveals that the flow features and distribution in the optimized swirl generator. Therefore, the new-type cyclone separator, which is expected to be applied in separation fields, has great actual using value.

Orthogonal experimental design of an axial flow cyclone separator

This paper presents a study of the combined system of vacuum membrane distillation (VMD) and mechanical vapor recompression (MVR) for the treatment of sulfuric acid solution. A lab-scale VMD setup with polytetrafluoroethylene (PTFE) microporous membranes using sulfuric acid solution as feed was used to investigate the effects of operating parameters on water production performance. The thermal efficiency in VMD process was then analyzed. Finally, further investigation about the energy recovery characteristic of the proposed system were carried out by analyzing the variation laws of the vapor saturated temperature rise of the compressor. The results showed that sulfuric acid solution could be concentrated up to 50 % by the VMD technology, and the separation efficiency was 99.9 %. However, the energy requirement was still larger due to lower thermal efficiency caused by the heat loss to the environment and the absence of recovery of latent heat of vaporization. The MVR process could achieve the enhancement of energy efficiency in the VMD process by recovering the latent heat of vaporization, the optimum permeate-side absolute pressure under different feed concentrations was obtained, which could ensure the minimum energy consumption, the energy saving of 65.5 % was observed in comparison with the conventional VMD system.

Performance analysis of treating sulfuric acid solution by the combined system of vacuum membrane distillation and mechanical vapor recompression

Supercritical Carbon Dioxide (S-CO2) Brayton cycles and Concentrating Solar Power (CSP) plants are gaining increasing attention due to environment pollution problems and their higher efficiencies. ...

Thermal performance analysis on steady-state and dynamic response characteristic in solar tower power plant based on supercritical carbon dioxide Brayton cycle

The invention discloses a trepanning electrolytic machining clamp for diffusers with insoluble blade trailing edges and a method thereof, and belongs to the field of electrolytic machining. The clampcomprises a left part and a right part, a cathode and an insulating block are located between a left clamp body and a right clamp body, a controllable liquid outlet gap is formed between the clamp bodies on two sides and the outer contour of the cathode, a liquid outlet corner type is used as the flowing way of electrolyte, the electrolyte flows in from the upper ends of blades and flows out fromthe liquid outlet gap, and a closed flow field is formed by the gap among an insulating sleeve, the cathode and the clamp. The insulating block is attached to the non-machining face of the cathode, sothat three-face machining of the leading edges, the concave surfaces and the convex surfaces of the blades is achieved. Concentric arc surfaces of leading and trailing edge supporting blocks are usedfor clamping annular workpieces. In the machining process, the adjacent machined blades are always sleeved with machined blade protecting sleeves, so that stray corrosion of the machined blades is effectively avoided. Through the trepanning electrolytic machining clamp and the method thereof, the problems of overlarge clamp pressure and electrolyte leakage easiness during diffuser trepanning electrolytic machining are solved, the stability of the flow field is improved easily, and machining quality is improved.

Chen Kaiqi

Papers

Thermodynamic and Economic Assessment on the Supercritical Compressed Carbon Dioxide Energy Storage System coupled with Solar Thermal Storage

Orthogonal experimental design of an axial flow cyclone separator

Performance analysis of treating sulfuric acid solution by the combined system of vacuum membrane distillation and mechanical vapor recompression

Thermal performance analysis on steady-state and dynamic response characteristic in solar tower power plant based on supercritical carbon dioxide Brayton cycle

Trepanning electrolytic machining clamp for diffusers with insoluble blade trailing edges and method thereof