A novel cogeneration cycle based on a recompression supercritical carbon dioxide cycle for waste heat recovery in nuclear power plants

2012 ◽  
Vol 10 (3) ◽  
pp. 346 ◽  
Author(s):  
Mortaza Yari
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Heat Recovery ◽  
Nuclear Power ◽  
Waste Heat Recovery ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Waste Heat ◽  
Cogeneration Cycle ◽  
Supercritical Carbon

scholarly journals Design optimization of supercritical carbon dioxide (s-CO2) cycles for waste heat recovery from marine engines

2021 ◽  
pp. 1-44
Author(s):  
Md. J. Hossain ◽  
Jahedul Islam Chowdhury ◽  
Nazmiye Balta-Ozkan ◽  
Faisal Asfand ◽  
Syamimi Saadon ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Thermal Efficiency ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Recovery System ◽  
Heat Recovery System ◽  
State Models ◽  
Supercritical Carbon

Abstract The global climate change challenge and the international commitment to reduce carbon emission can be addressed by improving energy conversion efficiency and adopting efficient waste heat recovery technologies. Supercritical carbon dioxide (s-CO2) cycles that offer a compact footprint and higher cycle efficiency are investigated in this study to utilize the waste heat of the exhaust gas from a marine diesel engine (Wärtsilä-18V50DF, 17.55 MW). Steady-state models of basic, recuperated and reheated s-CO2 Brayton cycles are developed and optimised for net work and thermal efficiency in Aspen Plus to simulate and compare their performances. Results show that the reheated cycle performs marginally better than the recuperated cycle accounting for the highest optimised net-work and thermal efficiency. For the reheated and recuperated cycle, the optimized net-work ranges from 648–2860 kW and 628–2852 kW respectively, while optimized thermal efficiency ranges are 15.2–36.3% and 14.8–35.6% respectively. Besides, an energy efficiency improvement of 6.3% is achievable when the engine is integrated with an s-CO2 waste heat recovery system which is operated by flue gas with a temperature of 373 °C and mass flow rate of 28.2 kg/s, compared to the engine without a heat recovery system.

Effect of Multicomponent Mixtures on Cycles With Supercritical Carbon Dioxide

2017 ◽  
Author(s):  
Ladislav Vesely ◽  
Vaclav Dostal
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Binary Mixtures ◽  
Power Plants ◽  
Waste Heat ◽  
The Other ◽  
Multicomponent Mixtures ◽  
Other Hand ◽  
Cycle Efficiency ◽  
Supercritical Carbon

With the increasing interest in solar and geothermal power plants as well as waste heat recovery systems from many technologies, the whole world is more focused on gas power cycles. Especially, the supercritical carbon dioxide (S-CO2) cycles are very interesting for these applications. This is due to many advantages of the S-CO2 cycles over the other cycles such as a steam-water cycle or helium cycle. On the other hand, S-CO2 cycles have also disadvantages. One of the disadvantages is presence of impurities in the cycles. The big question is the effect of these impurities in the CO2, which can occur as impurities or can be suitably added to the pure CO2. From the previous research, it is obvious that binary mixtures affect the cycle as they influence cycle component design and thus the overall efficiency of the power cycle. The biggest effect of mixtures is on the heat exchangers and compressor, which operate close to the critical point. The positive effect of the binary mixtures is observed in the recuperative heat exchanger. On the other hand, negative effects occurs in the cooler. Therefore, the Czech Technical University in Prague (CTU) conducted research on supercritical carbon dioxide cycles, which is focused on the effect of the gaseous admixtures in S-CO2 on the different cycle components. The main goal of this paper is to describe the effect of gaseous admixtures on the efficiency of the cycles and their effect on each component. The first part of the study is focused on the calculation of the basic cycles for binary mixtures and description of the effect on the compressor and the cycle efficiency. The second part of the study is focused on the calculation of the basic cycles for multicomponent mixtures. In this part, the effect of the mixtures for different compositions and amounts of the individual mixture components will be presented. The calculations are performed for pure CO2 and then for selected multicomponent mixtures. A basic multicomponent mixture includes mixtures from technology of carbon capture and storage. Other multicomponent mixtures are combinations of previously investigated gaseous admixtures such as He, CO, O2, N2, H2, CH4 and H2S. The last part of the study is focused on the optimization of individual basic cycles for different amount of admixtures in CO2. The result of this study defines the optimum composition of multicomponent mixtures and describes their effect on the cycle efficiency for the particular utilization of S-CO2 cycle.

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