Evaluation of Technical and Economic Efficiency of the Closed Hydrogen Cycle at the Nuclear Power Plant

Abstract

The article deals with the technical and economic efficiency of combining NPP with a hydrogen energy complex based on a closed hydrogen cycle. At the present stage of the study, the use of electrolysis hydrogen is a well-known approach to providing NPP with a base load during hours of minimum electrical load in the power system. Despite the existing concerns about the safety of using hydrogen fuel in the cycles of thermal power plants, this approach can improve the efficiency of NPP by accumulating unclaimed nighttime electricity and then generating additional electricity during hours of maximum electrical loads in the power system. This provides the further development of clean energy based on atomic-hydrogen technologies. The article conducts a study of the technical and economic efficiency of closed hydrogen cycle implementation at NPP depending on the cost of off-peak electricity for the needs of the hydrogen energy complex. The assessment of the main indicators of the technical and economic efficiency of hydrogen energy complex main equipment based on a closed hydrogen cycle which prevents hydrogen entering into the main steam cycle allows us to analyze the efficiency of combining NPP with a hydrogen energy complex. For this purpose, an increase in the power generated at a steam turbine installation is estimated due to an increase in steam consumption and efficiency of the flow part; based on the calculation of heat and mass transfer processes, the required area of heat exchange surfaces of a closed system of hydrogen superheating of steam is determined; the main capital and operating costs are calculated. As an example, a comparative assessment of two options for the closed hydrogen cycle implementation is carried out: at elevated and atmospheric pressure of combustion products. As a result of the calculations, we have obtained the main indicators of comparative technical and economic efficiency of the implementation of the proposed schemes for combining nuclear power plants with a hydrogen energy complex based on a closed hydrogen cycle. The zones of economic efficiency are determined depending on the cost of off-peak electricity for the needs of the hydrogen energy complex. As shown by calculations, reducing the pressure of combustion products to atmospheric leads to a certain decrease in the efficiency of the closed hydrogen cycle. The results obtained can be used in the development and optimization of systems for increasing the economically feasible maneuverability of NPP based on a combination with a hydrogen energy complex.