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

This paper presents exergy analysis results of a complex three cylinder steam turbine with nominal power 210 MW. The analysis is performed for each cylinder, cylinder part and whole turbine as well as for each segment of each turbine cylinder. In the observed turbine, Low Pressure Cylinder (LPC) has the highest exergy destruction (8668.15 kW) and the lowest exergy efficiency (87.19%), while Intermediate Pressure Cylinder (IPC) has the highest exergy efficiency (92.15%) of all cylinders. Exergy efficiency is the highest for each segment at each cylinder entrance and continuously decreases for all segments during steam expansion through each cylinder. In each cylinder, a segment which is the lowest influenced by the ambient temperature change is inlet segment – as steam expands through each cylinder, further segments became more and more influenced by the ambient temperature change. Steam re-heating process has a very beneficial influence on the exergy efficiency of the first two IPC segments (Seg. 3 and Seg. 4) which have the highest exergy efficiency in comparison to all other segments.

In this paper are presented results of the isentropic analysis related to the cylinders, segments and whole three cylinder steam turbine from the conventional power plant. In the analyzed steam turbine Low Pressure Cylinder (LPC) is the dominant mechanical power producer of all cylinders – it produces 130.16 MW of mechanical power in the real expansion process and it can produce 142.80 MW of mechanical power if the expansion conditions are ideal. The satisfactory isentropic performance of the whole High Pressure Cylinder (HPC) is a combination of two segment’s isentropic performance – one of these segments show extremely good isentropic performance (Seg2), but another segment (Seg1) shows very poor isentropic performance. Both Intermediate Pressure Cylinder (IPC) segments (Seg3 and Seg4) show similar isentropic performance, what result with the balanced IPC operation. LPC has an isentropic efficiency of 91.15%, what is the highest isentropic efficiency of all cylinders from the observed steam turbine. Whole observed steam turbine has an isentropic efficiency of 88.42% what is better isentropic performance in comparison to similar steam turbines from conventional power plants.

In this paper are presented isentropic analysis results of a steam turbine and each of its cylinders which operate in Municipal Solid Waste (MSW) power plant. Low Pressure Cylinder (LPC) which produces the highest real mechanical power has the lowest isentropic loss of all cylinders equal to 4344.75 kW, while High Pressure Cylinder (HPC) which produces the lowest real mechanical power has the highest isentropic loss of all cylinders equal to 5204.54 kW. Isentropic losses and isentropic efficiencies are reverse proportional, because the cylinder with the lowest isentropic loss (LPC) has the highest isentropic efficiency equal to 88.92%, while the cylinder with the highest isentropic loss (HPC) has the lowest isentropic efficiency equal to 84.58%. Surprisingly, isentropic efficiency of the Intermediate Pressure Cylinder (IPC) is equal to 86.80% only, which is higher in comparison to HPC but notably lower than LPC. The observed turbine strongly differs from other comparable steam turbines from the literature where IPC has notably higher isentropic efficiencies than both HPC and LPC. Whole observed steam turbine produces real mechanical power equal to 97513 kW, while its isentropic efficiency is equal to 86.87%.

This paper presents isentropic analysis results of the whole steam turbine (as well as turbine cylinders) from nuclear power plant. In the analyzed steam turbine, LPC (Low Pressure Cylinder) is the dominant mechanical power producer – mechanical power produced in the LPC is more than two times higher in comparison to mechanical power produced in the HPC (High Pressure Cylinder). Whole analyzed steam turbine produces real mechanical power equal to 1372.47 MW, while the highest possible mechanical power which can be produced in the whole turbine when all the losses are neglected (ideal mechanical power) equals 1686.96 MW. LPC has a notably higher isentropic efficiency than HPC, regardless of higher isentropic loss (isentropic efficiencies of the LPC and HPC are 84.41% and 74.84%, respectively). HPC has notably higher specific steam consumption and specific heat consumption in comparison to LPC. Whole turbine has an isentropic efficiency equal to 81.36%, isentropic loss equal to 314.48 MW, specific steam consumption of 9.15 kg/kWh and specific heat consumption of 3799.06 kJ/kWh, what is in the range of similar comparable steam turbines from nuclear power plants.

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%.

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.

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%.

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%.