International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

In this paper, two-cylinder steam turbine, which operates in nuclear power plant is analyzed from the energy viewpoint. Along with the whole turbine, energy analysis is performed for each turbine cylinder (High Pressure Cylinder – HPC and Low Pressure Cylinder – LPC). A comparison of both cylinders shows that the dominant mechanical power producer is LPC, which also has much higher energy loss and much lower energy efficiency. Therefore, any potential improvement of this steam turbine should be based dominantly on th e LPC, which also has a dominant influence on energy analysis parameters of the whole observed turbine. The whole turbine produces real (polytropic) mechanical power equal to 1247.69 MW, has energy loss equal to 352.70 MW and energy efficiency equal to 77.96%. According to obtained energy efficiency value it can be concluded that the whole analyzed steam turbine is comparable to main marine propulsion steam turbines, while its energy efficiency is much lower in comparison to steam turbines from conventional steam power plant s which operates by using superheated steam.

This paper presents an energy analysis of middle-power steam turbine with two cylinders (High Pressure Cylinder – HPC and Low Pressure Cylinder – LPC) and steam re-heater after the HPC (and before the LPC). Based on a steam operating parameters from the literature, performed energy analysis show that LPC develops higher power and has higher energy efficiency (81.45%) in comparison to HPC (which energy efficiency equals 80.12%). Re-heater is a heat exchanger (flue gases are used for steam heating) which has low energy loss (824.19 kW) and high energy efficiency (97.76%), what is expected energy performance of such heat exchanger. The entire analyzed turbine develops a power of 127480.60 kW and has energy loss equal to 29848.21 kW with energy efficiency of 81.03%.

In this paper is performed exergy analysis of high pressure feed water heating system and all of its components which operates in nuclear power plant. Four cases are observed: system operation in the base case and system operation in three optimized cases. Exergy analysis show that optimization by using different algorithms has a different influence on the exergy destructions, while all the algorithms increase whole system and its components exergy efficiencies. An increase in the ambient temperature increases exergy destructions and decrease exergy efficiencies of the whole observed system and its components, regardless of operation case. The highest exergy efficiency of the whole analyzed system is 96.12% and is obtained by using an IGSA algorithm at the lowest observed ambient temperature of 5 °C. By observing exergy destructions only, it should be noted that GA and IGSA algorithms give almost identical results.

This paper present analysis of energy flow streams through the main steam turbine (the turbine is used for commercial LNG carrier propulsion) at three different loads. An increase in the propulsion plant (and proportionally increase in the main turbine) load resulted with an increase in energy flow streams and with an increase in the amount of water droplets inside steam at the main turbine outlet. Analyzed turbine has three steam extractions which opening as well as the amount of energy flow stream delivered through each extraction, significantly differs at various loads. The analysis shows that the highest energy flow stream consumers from the main turbine are deaerator and high pressure feed water heating system.