Feedwater Pump Research Articles

A Reduced-Order Model of a Nuclear Power Plant with Thermal Power Dispatch

This paper presents reduced-order modeling of thermal power dispatch (TPD) from a pressurized water reactor (PWR) for providing heat to nearby heat consuming industrial processes that seek to take advantage of nuclear heat to reduce carbon emissions. The reactor model includes the neutronics of the reactor core, thermal–hydraulics of the primary coolant cycle, and a three-lump model of the steam generator (SG). The secondary coolant cycle is represented with quasi-steady state mass and energy balance equations. The secondary cycle consists of a steam extraction system, high-pressure and low-pressure turbines, moisture separator and reheater, high-pressure and low-pressure feedwater heaters, deaerator, feedwater and condensate pumps, and a condenser. The steam produced by the SG is distributed between the turbines and the extraction steam line (XSL) that delivers steam to nearby industrial processes, such as production of clean hydrogen. The reduced-order simulator is verified by comparing predictions with results from separate validated steady-state and transient full-scope PWR simulators for TPD levels between 0% and 70% of the rated reactor power. All simulators indicate that the flow rate of steam in the main steam line and turbine systems decrease with increasing TPD, which causes a reduction in PWR electric power generation. The results are analyzed to assess the impact of TPD on system efficiency and feedwater flow control. Due to the simplicity of the proposed reduced-order model, it can be scaled to represent a PWR of any size with a few parametric changes. In the future, the proposed reduced-order model will be integrated into a power system model in a digital real-time simulator (DRTS) and physical hardware-in-the-loop simulations.

Integration and capacity optimization of molten-salt heat storage in coal-fired power plant with carbon capture system

Developing a new generation of economical, low-carbon, and flexible coal-fired power plants (CFPP) is crucial for achieving the low-carbon transformation of the energy industry. Deploying molten salt heat storage (MSHS) in the CFPP can effectively enhance its peak shaving capability and reduce the limitations of carbon capture on wide range operation of the plant. To this end, this paper proposes four integration schemes for MSHS into the power plant-carbon capture system. The thermal efficiencies, exergy efficiencies, and peak shaving capabilities of the entire plant under different integration schemes are evaluated and compared. The results indicate that the optimal integration scheme involves utilizing hot reheat steam to heat the cold molten salt and further provide heat for the carbon capture system during the heat charging process and utilizing hot molten salt to heat the outlet water of the feed water pump during the heat discharging process, which achieves the highest thermal efficiency of 38.00 % and exergy efficiency of 37.09 % across the entire cycle. A novel integrated design, scheduling, and control optimization (IDSCO) method is proposed to find the optimal capacity configuration of MSHS, in which the investment, maintenance, fuel, carbon emission, and long-timescale and short-timescale load tracking deviation penalty costs are fully considered. A design parameter-aware control system is developed based on a multi-parametric programming model predictive control approach to ensure a fair evaluation of closed-loop dynamic performance under different configuration capacities. The simulation results demonstrate that the deployment of MSHS can significantly enhance the flexibility of the power plant-carbon capture system and the proposed IDSCO approach can reduce 17.05 % of load tracking deviation penalty cost and 1.38 % of totalized cost compared to the conventional configuration approach. This paper effectively leverages the potential of MSHS in enhancing the operational flexibility of CFPP-PCC system, thereby providing useful guidance for future deployment of MSHS within CFPP-PCC system.

Analysis of the reasons for the fracture of the heat-engine plant turbine vane of the power plant feedwater pump

Analysis of the reasons for the fracture of the heat-engine plant turbine vane of the power plant feedwater pump

Determination of Gain Scheduling Parameters for Loss of a Feedwater Pump Transient Mitigation Using Neural Networks

Transient mitigation for nuclear power plants is essential for safe operation. The fourth industrial revolution brings with it the potential for data-based predictive maintenance and identifying remaining time of life for degrading components. An improvement to predictive maintenance would be to address continued operation with faulty components between the time of identification and eventual replacement. The ability to perform data analysis and contemporary digital control systems allows for data-driven control system actions. A methodology is developed herein to train a neural network that can map desired system performance and current plant component capability to control system settings. Simulations of plant transients were recorded and used to train a neural network. This neural network was tested with different target performance goals. The results show that the trained neural network recommended settings that affected the control system response so as to meet the target performance goals.

Power Compatibility of Induction Motors in Industrial Grids Containing Synchronous Generators

Starting an induction motor causes voltage sag in the industrial grid that may disturb the operation of grid equipment. Direct-on-line starting is the simplest and most cost-effective method for starting induction motors, but also the most problematic. Large industries often use internal power plants with synchronous generators and starting powerful motors may impact the generator operations. The synchronous generators could be operated with the automatic or manual mode of voltage control. As the operation experience proves, the generator voltage control mode has a significant impact on the transient behaviours in the industrial power grid when starting a large induction motor. This article presents a case study of the synchronous generator tripping within a true medium-voltage industrial grid during the direct-on-line starting of a large induction motor driving the feed water pump. An analysis of the generator protection logs after the tripping showed that the synchronous generator was controlled in manual mode and its protection relay settings were exceeded. The transients initiated by induction motor starts were studied for possible configurations and operating conditions of the grid using a model developed on the Matlab/Simulink Software platform. The simulations have shown that concern about starting large motors in industrial grids containing internal synchronous generators needs to be solved considering the grid configurations and the coordination of generator protection and control devices.

Extended FOGI-FLL Based Seamless Control of Grid Synchronized BES-PV Fed Water Pump System

Extended FOGI-FLL Based Seamless Control of Grid Synchronized BES-PV Fed Water Pump System

Digital twin modeling and operation optimization of the steam turbine system of thermal power plants

The increasing deployment of renewable energy sources necessitates peak regulation services from thermal power plants, impacting their energy efficiency. Central to these plants, the steam turbine system significantly influences their operational efficiency. A digital twin model of this system was developed, integrating mechanism-driven and data-driven modeling methods. The neural network data-driven approach was specifically utilized for parameters such as feedwater pump speed and steam flow rate to the pump turbine. Other parameters were modeled with mechanism data hybrid driven modeling method. This model computes vital metrics such as low-pressure turbine exhaust steam enthalpy, work done and heat absorption per unit mass of steam, system efficiency, feedwater mass flow rate, and water-coal ratio—key for evaluating and enhancing the system's energy efficiency. An investigation into a reference case showed a decline in efficiency below design levels due to aging. By optimizing the live steam pressure and the cold-end system, relative improvements in energy efficiency of 0.35 % and 0.14 %, respectively, were achievable.

Waste to Energy

Boiler feed water pumps are at the heart of new energy production.

Energy management of solar photovoltaic fed water pumping system based BLDC motor drive using NBO–SDRN approach

Energy management of solar photovoltaic fed water pumping system based BLDC motor drive using NBO–SDRN approach

Performance analysis of small steam turbine in high back pressure heating unit

In view of the change of the operation mode of the small steam turbine of the high back pressure modified unit, the performance evaluation formula of the small steam turbine and the feed water pump is given. Through the performance test, the performance indexes of the small steam turbine and the feed water pump set are obtained, and the detailed data analysis is carried out. It is found that the modified small steam turbine and the feed water pump set do not meet the design requirements. The analysis of the test results, found the reasons for the performance is not up to the standard, and gave the next step.

Tribological behavior of diamond coated reaction-bonded silicon carbide under dry and seawater environment

Ceramic seal materials such as Silicon carbide (SiC) and Reaction-Bonded SiC (89%SiC and 11 % free Silicon) are widely used in mechanical pumps, compressors, and feed water pumps to prevent the fluid leakage between the two rotating shafts. In a continuously harsh environment, these mechanical seal materials undergo high friction and wear due to the high asperity-to-asperity contact between the two mating parts and generate high frictional heat at the interface. This scenario induces seal failure under high operating conditions. Especially in corrosive mediums such as acids, high pH value solutions, and hard abrasive media can cause aggressive seal failure. To reduce production downtime and improve the longevity of the mechanical seal, the surface of the seal material needs to be engineered with a suitable coating that will satisfy the required properties of high hardness, chemically inertness, and low friction coefficient. In this regard, we have come up with a super hard coating material such as diamond (Micro-crystalline) on the surface of Reaction-Bonded SiC using the hot filament CVD (HFCVD) method to meet the above-required properties. In this work, we have carried out a systematic study on the tribological effect of uncoated, and diamond-coated seal material against silicon nitride ceramic under a dry and seawater environment. The initial physical characteristics such as surface morphology, surface roughness, and Raman analysis were performed on the samples before and after coating. To understand the friction and wear characteristics, the linear reciprocating tribometer test (Ball on Flat) was conducted on the uncoated and diamond-coated samples using a universal tribometer for an operating period of 36,000 cycles. The experimental results show that the diamond-coated sample exhibits a low friction coefficient (0.05 ± 0.01) compared to the uncoated sample (Friction coefficient (CoF) = 0.24 ± 0.037) at a normal load of 10 N with a frequency of 10 Hz under a seawater environment. Similarly, under dry conditions for the same tribo-test parameters, the diamond-coated sample (CoF = 0.06 ± 0.02) outperforms compared with the uncoated sample (CoF = 0.42 ± 0.17) at a percentage improvement of 85 %. From the observed results, we conclude that diamond-coated ceramic seals are considered a suitable alternative to commercially available seals in terms of high operating conditions and durability under both wet (seawater) and dry running operations.

Construction of the Dynamic Model and Control System for the Canadian Supercritical Water–Cooled Reactor Power Plant

Canada has proposed the supercritical water–cooled reactor (SCWR) concept as one of the Generation IV nuclear reactors. In the SCWR power plant, the supercritical water is heated in the reactor and then flows to the turbine directly. Therefore, knowledge of the dynamic behaviors of the system is necessary for the stable operation of the power plant. There is still a lack of study on the control system for the proposed SCWR power plant. In this study, a dynamic model for the entire SCWR power plant is constructed that includes the reactor, turbine, condenser, and feedwater pump. Based on the model, the open-loop characteristics of the system when subjected to perturbations in the inputs are analyzed. Subsequently, a feedback control strategy is adopted to regulate the outputs of the system when there are disturbances. The evaluation of the performance of the control system shows that the proposed control system can return the plant back to the operating conditions effectively.

Comparison of event tree/fault tree and convolution approaches in calculating station blackout risk in a nuclear power plant

Station blackout (SBO) risk is one of the most significant contributors to nuclear power plant risk. In this paper, the sequence probability formulas derived by the convolution approach are compared with those derived by the conventional event tree/fault tree (ET/FT) approach for the SBO situation in which emergency diesel generators fail to start. The comparison identifies what makes the ET/FT approach more conservative and raises the issue regarding the mission time of a turbine-driven auxiliary feedwater pump (TDP), which suggests a possible modeling improvement in the ET/FT approach. Monte Carlo simulations with up-to-date component reliability data validate the convolution approach. The sequence probability of an alternative alternating current diesel generator (AAC DG) failing to start and the TDP failing to operate owing to battery depletion contributes most to the SBO risk. The probability overestimation of the scenario in which the AAC DG fails to run and the TDP fails to operate owing to battery depletion contributes most to the SBO risk overestimation determined by the ET/FT approach. The modification of the TDP mission time renders the sequence probabilities determined by the ET/FT approach more consistent with those determined by the convolution approach.

BLDC Motor Driven Solar PV Array Fed Water Pumping System Employing Zeta Converter

Abstract—This paper proposes a simple, cost effective and efficient brushless DC (BLDC) motor drive for solar photovoltaic (SPV) array fed water pumping system. A zeta converter is utilized in order to extract the maximum available power from the SPV array. The proposed control algorithm eliminates phase current sensors and adapts a fundamental frequency switching of the voltage source inverter (VSI), thus avoiding the power losses INTERNATIONAL JOURNAL OF SCIENTIFIC RESEARCH IN ENGINEERING AND MANAGEMENT (IJSREM) VOLUME: 07 ISSUE: 09 | SEPTEMBER - 2023 SJIF RATING: 8.176 ISSN: 2582-3930 © 2023, IJSREM | www.ijsrem.com DOI: 10.55041/IJSREM25857 | Page 2 due to high frequency switching. No additional control or circuitry is used for speed control of the BLDC motor. The speed is controlled through a variable DC link voltage of VSI. An appropriate control of zeta converter through the incremental conductance maximum power point tracking (INC-MPPT) algorithm offers soft starting of the BLDC motor. The proposed water pumping system is designed and modeled such that the performance is not affected under dynamic conditions. The suitability of proposed system at practical operating conditions is demonstrated through simulation results using MATLAB/ Simulink followed by an experimental validation.

Statistical process control versus deep learning for power plant condition monitoring

This study compares four models for industrial condition monitoring including a principal components analysis (PCA) approach and three deep learning models, one of which is a new, lightweight version of another. We also propose a simple attention mechanism for enchancing deep learning models with better predictions and feature importance. Two datasets are used, one simulated from the Tennessee Eastman Process, the other from two feedwater pumps at a Danish combined heat and power plant. Our final results show evidence in favour of the PCA-based approach as it has detection ability comparable to the deep learning approaches as well as faster training time, fewer hyperparameters, as well as robustness to changing operating conditions. We conclude the paper by putting into perspective the importance of building up complexity incrementally with a recommendation to start modelling with simpler and well-tested models before the adoption of more advanced, less transparent models.

Corrosion Detection and Surface Repair with Coatings on Condensate Storage Tanks Internal Surfaces

In the Nuclear power plant Krško, there are two single hull condensate storage tanks with floating diaphragm each containing up to 757 m3 of demineralized water. The main purpose of these two storage tanks is to provide a capacity of cooling water for cooling the reactor coolant system via steam generators with the use of auxiliary feedwater pumps. This is a very important function from the safety point of view and that is the reason that both storage tanks are listed as safety class 3 components. It is also possible to fill up the condensate system if other means are not available. Condensate storage tanks are subject to periodic testing and periodic inspections to determine the condition of the components. Both tanks are in operation since the start-up of the powerplant, are located outside, and are exposed to different degradation processes. There was a concern that the tanks are leaking because there were often small puddles of water near the tanks. There were no changes in the levels of tanks. The design of tanks is a single hull, so there is no indication if a small leak is present.In the outage 2018, both tanks were emptied and examined with NDE methods to find any corrosion damage of bottom plates and any untight spots on adjacent welds.The article is about the NDE methods that were used (Magnetic Flux Leakage, Ultrasonic and Vacuum Box inspection) to determine the condition of the floor plates and adjacent welds as well as the process of internal surface reparation with coatings. Process of coatings qualification for use in safety class components is also explained: dedication process for material up-grade from non-safety related to safety-related because CY tank linings are classified as safety-related according to RG 1.54, rev 2 and corresponding ASTM standards and NEK technical specification SP-A5001. All activities for surface repair with coatings shall comply with safety-related requirements. Also, extensive immersion tests with selected and specially defined parameters were performed in NEK chemical laboratory in order to select the most suitable coating system for surface repair of CY tank floor lining. Further details concerning immersion tests are presented below.

Integrated thermohydraulic transient testing of steam extraction loop system to support joint electricity-hydrogen production using generic boiling water reactor

The economic competitiveness of the current fleet of light water reactors may be improved by coupling nuclear reactors to industrial facilities. This will allow flexible use high-quality steam or electric power from the reactor when the cost of electricity is low compared to the generation cost. One promising application is hydrogen production. Understanding the nuclear plant response to steam offtake is important for safe operation of the reactor facility. Conceptual analysis has been performed for coupling pressurized water reactors (PWRs) to high temperature steam electrolysis hydrogen production; however, corresponding work done for boiling water reactors (BWRs) has not been published, even though BWRs make up 30% of the US operating fleet. This paper demonstrates the feasibility of coupling a generic BWR to a hydrogen production facility. The system response is analyzed for a 15% reduction in the electrical power output. This work shows that when steam is extracted from the main steam header without appropriate controls modifications, reactor power will increase beyond 100% rated power. We present addition analysis to maintain power below rated conditions by varying feedwater recirculation pump speeds.

Analysis and Referential Significance of a Breakdown Accident of the Main Feed Water Pump in a 350 MW Supercritical CFB Boiler

Analysis and Referential Significance of a Breakdown Accident of the Main Feed Water Pump in a 350 MW Supercritical CFB Boiler

Multi-Resonant Third-Order Generalized Integrator Based PLL for Seamless Control of Solar-Battery Fed Grid Synchronized Water Pumping System

The solar photovoltaic array and battery energy storage fed grid interfaced water pumping system operates in islanding mode under grid outage. There is a need to synchronize such system to grid on recovery of grid to facilitate interconnection and interoperability between the two. Thus, a multi-resonant third-order generalized integrator (MR-TOGI) based phase-locked loop (PLL) to realize seamless control for grid synchronization of solar-battery fed water pumping system is presented in this paper. The presented MR-TOGI-PLL rejects lower-order harmonics and DC-offset by using developed MR-TOGI based quadrature signal generation (QSG). Besides, MR-TOGI-QSG based current control is realized under grid-connected mode to improve power quality at grid in accordance to the IEEE-519 standard. This current control even operates photovoltaic array at its peak power, thereby enabling its direct connection to DC-link. While MR-TOGI-QSG based voltage control is realized for islanding mode to ensure uninterrupted operation of system under grid outage. Meanwhile, power management system is also developed to manage power flow among different system components. The detailed analysis of MR-TOGI-PLL is performed to illustrate its advantages. Test performances of system are obtained for various operating scenarios including MR-TOGI-PLL based synchronization to demonstrate effective operation of the system.

Feasibility Study on Frequency Conversion Transformation of Electric Feedwater Pump in Nuclear Power Plant

In order to study the feasibility of frequency conversion of electric feedwater pump in nuclear power plant, and to provide reference for the improvement of electric feedwater pump in nuclear power plant and new nuclear power plant, this paper discusses the technical and economic aspects, and analyzes the feasibility of frequency conversion transformation of electric feed pump in nuclear power plant. The results show that there is no technical difficulty for the electric feedwater pump of nuclear power plant from the technical point of view, and the economic analysis shows that it will take about 4 years to recover the cost for the frequency conversion of the electric feedwater pump of nuclear power plant. Therefore, the frequent participation in the peak load of the power grid units can be considered for transformation, For the nuclear power units that serve as the base load of the power grid, the cost can be recovered in about 6 years by eliminating the loss of capacity, and they can be retrofitted according to the needs of the plants themselves.