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

: In this paper are investigated and presented the most influential operating parameters and the guidelines for proper arrangement of pumps in the condensing/feedwater heating system. The observed system operates in marine steam propulsion power plant. In the analyzed system operates three pumps: Condensate Pump (CP), Auxiliary Pump (AP) and FeedWater Pump (FWP). Considering all observed pumps, FWP is the dominant mechanical power consumer because it operates with the highest pressure difference and with the highest fluid mass flow rate. Used mechanical power and losses (energy and exergy) of all observed pumps are directly proportional to fluid mass flow rate through the pump – higher fluid mass flow rate through the pump will result with higher mechanical power used by pump and with higher losses (both energy and exergy) and vice versa. Energy and exergy efficiencies of the observed pumps have reverse proportional trends. The most influencing factor related to the pump efficiency (both energy and exergy) is the pump inlet pressure. Pump inlet pressure is directly proportional to the pump exergy efficiency, but simultaneously pump inlet pressure is reverse proportional to pump energy efficiency.

In this paper are presented results of the energy and exergy analyses related to the steam generator from nuclear power plant at four observed operating regimes. It is shown how the optimization processes and algorithms influence observed steam generator operation. The highest steam generator energy outlet is equal to 3012.17 MW and the lowest energy loss is 0.07 MW – both of them are obtained by using Genetic Algorithm (GA). Whale Optimization Algorithm (WOA) gives fluid operating parameters which will result with the lowest steam generator exergy destruction (107.05 MW) and the highest exergy efficiency (92.709%) in comparison to all other operating regimes. During the increase in ambient temperature from 5 °C up to 45 °C the lowest decrease in steam generator exergy efficiency (equal to 2.0136%) is obtained in the second operating regime which operating parameters are defined by using WOA. Final conclusion which can be derived from the observed research is that WOA has the most beneficial influence on the steam generator operation.

This paper presents an exergy analysis of a complex four-cylinder steam turbine, which operate in a coal-fired power plant. Analyzed steam turbine consists of high pressure single flow cylinder (HPC), intermediate pressure dual flow cylinder (IPC) and two low pressure dual flow cylinders (LPC1 and LPC2). The highest part of cumulative mechanical power (787.87 MW) is developed in IPC (389.85 MW) and HPC (254.67 MW), while both low pressure cylinders develop a small part of cumulative mechanical power (70.29 MW in LPC1 and 73.06 MW in LPC2). Cylinder exergy destruction (cylinder exergy power loss) continuously increases as the steam expands through the turbine. The lowest exergy destruction has HPC (13.07 MW), followed by the IPC (20.95 MW), while the highest exergy destructions are noted in low pressure cylinders (24.37 MW in LPC1 and 27.17 MW in LPC2). Cylinder exergy efficiency continuously decreases as the steam expands through the turbine. The highest exergy efficiency has HPC (95.12%), followed by the IPC (94.90%) and LPC1 (74.25%), while the lowest exergy efficiency of all cylinders is obtained in LPC2 (72.89%). Exergy efficiencies of LPC1 and LPC2 are much lower in comparison to other low pressure dual flow cylinders from comparable steam power plants. The whole observed steam turbine has exergy
efficiency equal to 90.20%.