• DOMINANT TECHNOLOGIES IN “INDUSTRY 4.0”

    Energy and exergy analysis of steam generator from nuclear power plant at four operating regimes

    Industry 4.0, Vol. 9 (2024), Issue 5, pg(s) 160-163

    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.

  • TRANSPORT TECHNICS. INVESTIGATION OF ELEMENTS. RELIABILITY

    Analysis of main feedwater pump from steam power plant at three loads

    Trans Motauto World, Vol. 9 (2024), Issue 1, pg(s) 6-9

    This paper presents results of the Main Feedwater Pump (MFP) isentropic and exergy analyses at three power plant loads. Observed MFP is a constituent component of condensate/feedwater sub-system from conventional steam power plant. In real exploitation conditions, MFP uses mechanical power higher than 3000 kW, considering all observed power plant loads. Main isentropic and exergy parameters of the MFP at various plant loads show the same general trends (increase in power plant load simultaneously increases MFP losses and efficiencies and vice versa, from both isentropic and exergy viewpoints). Analyzed MFP has high isentropic and exergy efficiencies, considering all plant loads and ambient temperatures (at any plant load MFP isentropic efficiency is higher than 85%, while the lowest MFP exergy efficiency is equal to 89.24% at the lowest observed plant load and the highest observed ambient temperature). The change in isentropic and exergy efficiency of the MFP is small if all observed plant loads and ambient temperatures are taken into consideration.

  • INNOVATIVE SOLUTIONS

    Exergy analysis of a two-cylinder steam turbine from combined cycle power plant at three operating regimes

    Innovations, Vol. 12 (2024), Issue 1, pg(s) 29-32

    This paper presents an exergy analysis of a two-cylinder low power steam turbine from combined cycle power plant at three operating regimes. The highest mechanical power produced in the whole turbine is 6807.24 kW in Operating regime 1. Cylinders of the observed turbine did not have the same operation dynamics in relation to produced mechanical power in all operating regimes. In each operating regime High Pressure Cylinder (HPC) has lower exergy destruction and higher exergy efficiency in comparison to Low Pressure Cylinder (LPC) due to the influence of wet steam which expands through the last LPC stages (water droplets in wet steam increases LPC exergy destruction and decreases LPC exergy efficiency). Whole turbine exergy efficiency is between 51.62% (in Operating regime 2) and 64.98% (in Operating regime 1). This range of exergy efficiencies can be expected for a low power steam turbine. An increase in the ambient temperature decreases exergy efficiency of the whole turbine and both turbine cylinders, regardless of the observed operating regime. The exergy efficiency of the LPC is low in all operating regimes, so any improvements should be based on this cylinder first.

  • SCIENCE

    Nuclear power plant steam re-heating system – exergy analysis at four different operating regimes

    Science. Business. Society., Vol. 7 (2022), Issue 2, pg(s) 38-41

    In this paper is performed exergy analysis of steam re-heating system, through all of its components, which operate in nuclear power plant. Analyzed re-heating system consists of the moisture separator (MS) and two re-heaters (RH1 and RH2) and is observed in four different operating regimes. MS has significantly lower exergy destructions and significantly higher exergy efficiencies in comparison to both re-heaters, regardless of the observed operating regime. MS and both re-heaters did not achieve the lowest exergy destructions and the highest exergy efficiencies in the same operating regime which notably complicated possible improvements. Further research of presented re-heating system will be based on operation improvement of RH1 and RH2 – performed exergy analysis shows that MS operation in any operating regime leaves no room for further improvement.

  • MACHINES

    Exergy analysis of a complex three-cylinder steam turbine at various loads

    Machines. Technologies. Materials., Vol. 18 (2024), Issue 1, pg(s) 3-6

    Exergy analysis results for the Whole observed steam Turbine and each of her cylinders at three loads are presented in this paper.
    Observation of all cylinders shows that LPC (Low Pressure Cylinder) is the dominant mechanical power producer at the highest observed load, while at partial loads the dominant mechanical power producer is IPC (Intermediate Pressure Cylinder). At Load 100% Whole Turbine produces mechanical power equal to 341.11 MW. IPC is the cylinder with the lowest exergy destruction and the highest exergy efficiency (higher than 95%) at all observed loads. The exergy efficiency of the Whole Turbine (WT) continuously increases during the increase in turbine load (WT exergy efficiency is the lowest at Load 50% and equal to 91.36%, while at the Load 100% WT exergy efficiency is the highest and equal to 92.93%). Analyzed turbine is projected to operate dominantly on the Load 100% because at that load the exergy efficiencies of all cylinders and Whole Turbine are higher than 91%.

  • MACHINES

    Exergy analysis of steam turbine from ultra-supercritical power plant

    Machines. Technologies. Materials., Vol. 17 (2023), Issue 3, pg(s) 98-101

    In this paper is presented an exergy analysis of steam turbine (along with analysis of each cylinder and cylinder part) from ultrasupercritical power plant. Observation of all the cylinders shows that IPC (Intermediate Pressure Cylinder) is the dominant mechanical power producer (it produces mechanical power equal to 394.44 MW), it has the lowest exergy loss and simultaneously the highest exergy efficiency (equal to 95.84%). HPC (High Pressure Cylinder) has a very high exergy efficiency equal to 92.37% what confirms that ultrasupercritical steam process is very beneficial for the HPC (and whole steam turbine) operation. LPC (Low Pressure Cylinder) is a dissymmetrical dual flow cylinder, so both of its parts (left and right part) did not produce the same mechanical power, did not have the same exergy loss, but their exergy efficiency is very similar and in a range of entire LPC exergy efficiency (around 82.5%). Whole observed steam turbine produces mechanical power equal to 928.03 MW, has exergy loss equal to 93.45 MW and has exergy efficiency equal to 90.85%. The exergy efficiency of the whole analyzed steam turbine is much higher in comparison to other steam turbines from various conventional power plants.

  • MACHINES

    Exergy analysis of a complex four-cylinder steam turbine

    Machines. Technologies. Materials., Vol. 16 (2022), Issue 1, pg(s) 3-7

    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%.

  • TRANSPORT TECHNICS. INVESTIGATION OF ELEMENTS. RELIABILITY

    Exergy analysis of three cylinder steam turbine from supercritical coal-fired power plant

    Trans Motauto World, Vol. 6 (2021), Issue 2, pg(s) 34-37

    In this paper is performed exergy analysis of three cylinder steam turbine from the supercritical coal-fired power plant. Exergy analysis parameters were calculated for the whole turbine and each cylinder for the ambient temperature range between 5 °C and 45 °C. The dominant mechanical power producer of all the cylinders is a low pressure cylinder (LPC) which produces 262.06 MW of mechanical power. An increase in the ambient temperature increases exergy destructions and decreases exergy efficiencies of the whole turbine and each cylinder. Exergy analysis shows that LPC is a cylinder with the highest exergy destruction (between 24.67 MW and 28.24 MW) and the lowest exergy efficiency (between 82.27% and 84.16%) in comparison to the other cylinders. Exergy destruction of the whole observed turbine is between 67.85 MW and 77.62 MW, while the whole turbine exergy efficiency ranges between 89.47% and 90.67%. Inside the observed steam turbine, LPC is the most influenced by the ambient temperature change, therefore future research and possible optimization should be specifically based on this cylinder.

  • TECHNOLOGIES

    Exergy analysis of base and optimized high pressure feed water heating system from nuclear power plant

    Machines. Technologies. Materials., Vol. 15 (2021), Issue 3, pg(s) 103-106

    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.

  • VEHICLE ENGINES. APPLICATION OF FUELS TYPES. EFFICIENCY

    Energy and exergy evaluation of co2 closed-cycle gas turbine

    Trans Motauto World, Vol. 5 (2020), Issue 4, pg(s) 143-146

    This paper present energy and exergy evaluation of CO2 closed-cycle gas turbine process. The most important operating parameters of the whole observed cycle, as well as of each of its constituent components are presented and discussed. In the observed process, produced useful mechanical power for the power consumer drive is equal to 5189.78 kW, while the energy efficiency of the whole cycle is equal to 36.6%. Heat Regenerator is a crucial component of the observed process – without its operation energy efficiency of the whole cycle will be equal to only 16.91%. From the exergy aspect, Turbocompressor (TC) and Turbine (TU) shows good performances because its exergy efficiencies are higher than 90%. Regenerator exergy efficiency could be increased by lowering the temperature of the ambient in which analyzed CO2 closed-cycle gas turbine operates.

  • VEHICLE ENGINES. APPLICATION OF FUELS TYPES. EFFICIENCY

    Energy and exergy analysis of deaerator from combined-cycle power plant

    Trans Motauto World, Vol. 5 (2020), Issue 2, pg(s) 64-67

    Energy and exergy analysis of deaerator from combined-cycle power plant is presented in this paper. The deaerator is analyzed in three operating regimes and in various ambient conditions. The lowest deaerator energy loss of 525.60 kW and the highest energy efficiency of 78.21 % are obtained for the lowest water temperature at the deaerator outlet – in the same operating regime is obtained the lowest deaerator exergy efficiency. Decrease in the ambient temperature resulted simultaneously with an increase in deaerator exergy destruction and with increase in exergy efficiency. Deaerator exergy efficiency in each operating regime and for each observed ambient temperature significantly varies (from 13.82 % to 45.94 %). From the efficiency aspect, deaerator energy and exergy analysis show diametrically opposed results in two observed operating regimes.

  • MACHINES

    Exergy analysis of steam condenser at various loads during the ambient temperature change

    Machines. Technologies. Materials., Vol. 14 (2020), Issue 1, pg(s) 12-15

    The paper presents an exergy analysis of steam condenser at three different loads and in the ambient temperature range between 5 °C and 20 °C. An increase in the condenser load and increase in the ambient temperature resulted with an increase in steam condenser exergy destruction (exergy power losses). At low load, condenser exergy destruction is for the order of magnitude lower if compared to middle and high condenser loads. Decrease of the condenser load and decrease of the ambient temperature resulted with an increase in condenser exergy efficiency. The highest steam condenser exergy efficiencies are obtained at the lowest observed ambient temperature of 5 °C and amounts 81.47 % at low condenser load, 76.10 % at middle condenser load and 74.54 % at high condenser load. From the exergy viewpoint, the optimal condenser operating regime is low load and the lowest possible ambient temperature.