Failure analysis on circulating water pump of duplex stainless steel in 1000MW ultra-supercritical thermal power unit

Ma, Yue-Yue; Yan, Shi; Yang, Zhen‐Guo; Qi, Guo-Shui; He, Xin-You

doi:10.1016/j.engfailanal.2014.09.014

Cited by 18 publications

(4 citation statements)

References 31 publications

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“…There is a screening system to filter seawater in seawater so that water pumped by CWP avoids solid waste that can interfere with the cooling system's performance. A circulating Water Pump (CWP) is a pump used to pump seawater towards the condenser [10]. In PLTGU Grati Block I there are two CWPs with the same specification.…”

Section: Cooling Systemmentioning

confidence: 99%

Optimization of Condenser Backwash Method to Maintain Condenser Performance During the Backwash Process in PLTGU Grati

Nurrohman,

Suwandono,

Sahbana

et al. 2022

j. of sci. and appl.eng.

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The condenser is a device used to change the water vapor phase that has been used to rotate the turbine blade into a liquid phase by condensing it. When the condenser tube is dirty, it can disrupt the steam condensation process which affects the efficiency of the condenser. To overcome this problem a condenser backwash is carried out.Â Â Condenser backwash has a good influence on unit efficiency but backwash activities also reduce production by decreasing vacuum condensers and steam turbine loads. When the vacuum condenser backwash process decreases + - 24 mmHg and the steam turbine load decreases + - 8 MW.The condenser backwash process is carried out from the control room with the observation of parameters from the local area or equipment. Backwash condensers are done one by one as needed. The condenser type in PLTGU Grati Block I is a type of crossflow with two sides, namely, side A and side B. Each side of the condenser has a different sequence backwash condition. This study will be carried out a backwash method that is different from the sequence of automatic sequences.In the normal condenser backwash activity of data table 3 we can know there is a decrease in steam turbine load Â± 8MW and a decrease in vacuum Â± 24 mmHg. This is because at a certain period the condenser performance is reduced because at the time of switching valve one side of the condenser is not irrigated by seawater so that the heat transfer in the condenser is reduced which has an impact on a load of steam turbine and vacuum condenser. After the research was obtained that the greater the opening of the valve inlet when the condenser backwash then the decrease in vacuum and steam turbine load decreased even no decrease in load.The backwash method that can be done to keep the vacuum condenser and steam turbine load stable is by maneuvering the valve inlet, outlet, and condenser backwash valve. The results of the analysis obtained were a more stable decrease in steam turbine production in 0 MW and a decrease in the vacuum of 14 mmHg.

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Section: Cooling Systemmentioning

confidence: 99%

Optimization of Condenser Backwash Method to Maintain Condenser Performance During the Backwash Process in PLTGU Grati

Nurrohman,

Suwandono,

Sahbana

et al. 2022

j. of sci. and appl.eng.

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“…Nowadays, nuclear energy technology is developing rapidly, and nuclear electricity accounts for 11% of the global electricity generation [3]. The Circulating Water Pump (CWP) is an important facility in the cooling system of nuclear power plants, which is used to pump seawater into a condenser for cooling steam [4,5]. Unstable flow can exacerbate pump vibration and flow-induced force pulsation, while excessive loads can lead to damage in the rotor system, thereby impacting the long-term stable operation of the CWP and reducing the efficiency of the power generation system.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Unsteady Internal Flow and Its Induced Structural Response in a Circulating Water Pump

Lu,

Yao,

Zheng

et al. 2024

Water

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As critical equipment in nuclear power systems, the stability of circulating water pumps (CWP) directly impacts the efficiency of power plants. To investigate the impact mechanisms of the unsteady flow characteristics and flow-induced forces on the rotation system, numerical simulation methods were employed to calculate the internal flow of a volute mixed-flow CWP under different flow rates (0.8Qd, 1.0Qd, 1.2Qd). The flow field results indicate that, under the part-load condition, the flow within the volute is chaotic with high energy losses, while under the over-load condition, there is a significant velocity gradient within the impeller, leading to relatively severe flow losses. Additionally, the rotor–stator interface is a major factor in flow-induced pulsations, and the asymmetric pressure distribution within the volute results in radial force imbalance. The finite element method (FEM) results indicate that the position of maximum stress on the pump shaft is closely related to the ratio of radial and axial force. Increasing the flow rate appropriately has been noted to be advantageous in reducing flow-induced forces and their amplitude, consequently diminishing the forces on the rotation system and improving the long-term operational stability of the CWP.

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“…Ferrite/austenite duplex stainless steel (DSS) possesses excellent toughness, weldability, good corrosion resistance, and high strength, making it a promising material for numerous key energy fields, including marine engineering, petrochemicals, and nuclear power [1]. However, the welding process, which is typically employed to join components in DSS applications, may lead to the precipitation of unfavorable phases, such as Cr-rich carbides and sigma phases [2], or an unbalanced proportion of ferrite and austenite in the heat-affected zone (HAZ), resulting in local pitting corrosion, preferential corrosion, and mechanical property deterioration [3][4][5]. Andrea Putz [6] adopted a stationary arc to investigate the thermal treatment of multi-pass welding and found that the unfavorable precipitation of the secondary phase was observed at 575-1100 • C in both samples.…”

Section: Introductionmentioning

confidence: 99%

The Microstructure Evolution and Mechanical Properties of Rotary Friction Welded Duplex Stainless Steel Pipe

Zhang

Xie

et al. 2023

Materials

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The use of duplex stainless steel (DSS) in various fields is promising due to its excellent anti-corrosion properties, but traditional welding can lead to the formation of unfavorable phases that deteriorate its quality. This study aimed to use the rotary friction weld (RFW) technique to prevent the formation of harmful phases in the welding of an S32205 alloy pipe. The welding parameters used included a rotating speed of 20 m/s, a friction pressure of 10 MPa, a friction time of 30 s, and a forging pressure of 30 MPa. The microstructure and mechanical properties of the resulting RFWed joint were investigated. The results revealed that the weld zone exhibited a microstructure consisting of ferrite and austenite phases, with no deleterious phase detected. The ferrite content was measured to be 53.3%, 54.5%, and 68.7% in the base metal, thermomechanical affected zone (TMAZ), and weld, respectively, owing to the rapid cooling rate in the RFW process, which prevented any harmful phase formation in the weld zone. Furthermore, the RFW process successfully produced an ultrafine grain with a ferrite/austenite grain size of 0.40 μm and 0.41 μm, respectively. The weld zone and TMAZ contained more low-angle grain boundaries (LAGBs) compared to the base metal, which was attributed to the dynamic recovery (DRV) within a grain. The high heating and cooling rates and short welding time of the RFW process did not allow sufficient time for the dynamic recrystallization of the microstructure in the weld zone. However, a slight increase in the ferrite content in the weld zone resulted in grain refinement and an increase in the dislocation density, resulting in a slight increase in the 358 HV0.2 hardness and 823 MPa tensile strength of the weld zone. This study offers a novel approach for obtaining ultrafine grain duplex stainless steel pipes with exceptional mechanical properties through the application of RFW.

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Failure analysis on circulating water pump of duplex stainless steel in 1000MW ultra-supercritical thermal power unit

Cited by 18 publications

References 31 publications

Optimization of Condenser Backwash Method to Maintain Condenser Performance During the Backwash Process in PLTGU Grati

Optimization of Condenser Backwash Method to Maintain Condenser Performance During the Backwash Process in PLTGU Grati

Analysis of Unsteady Internal Flow and Its Induced Structural Response in a Circulating Water Pump

The Microstructure Evolution and Mechanical Properties of Rotary Friction Welded Duplex Stainless Steel Pipe

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