Power Plant Unit Research Articles

Матричное моделирование и диагностика состояния регенеративных подогревателей высокого давления

Increasing the efficiency of heat exchangers is a promising area of energy saving, which is one of the priority areas of the development of science, engineering, and technology in the Russian Federation. Improvement of heat and mass transfer in regenerative heaters and condensers of turbine units of thermal power plants can significantly increase the operating efficiency of power equipment. Diagnostics of the condition and improvement of operating modes of the high-pressure regenerative heater which are an integral part of regenerative heating systems for feedwater of turbine units, are urgent scientific and practical tasks. To develop a model of a high-pressure regenerative heater, the methodology of matrix formalization of the description of heat and mass transfer processes has been used. To solve problems of diagnosing the state of heating surfaces of heat exchange equipment, mathematical programming methods have been applied. Within the framework of the matrix formalization methodology, an approach to modeling and solving diagnostic problems of multi-stage heat exchangers considering the phase transition in coolants has been developed. The sensitivity of the resulting model to input signals has been studied. Solutions of the problem of diagnosing the state of a high-pressure regenerative heater have been obtained and analyzed. Analysis of the obtained calculated results has shown an adequate description using the model of the real heat exchange process for the analyzed heater and the possibility to use the proposed model for monitoring and operational diagnostics of power equipment. The proposed approach allows us to formulate and solve inverse problems of diagnosing the state of equipment of heat exchange installations for various purposes.

Design and performance evaluation of an off-grid hybrid solar system in a remote location: A case study of Legundi Island

Legundi Island, located in Lampung Bay, Indonesia, has high solar energy potential but still relies on Diesel Power Plants. This research aims to design a hybrid Solar Power Plant and Diesel Power plant system that is environmentally friendly and reliable. Analysis was conducted using the Homer software.•This research designs a hybrid Solar Power Plant system with a capacity of 170.2 kWp and a battery of 1,036 kWh, integrated with three existing Diesel Power Plants units with a capacity of 200 kW.•This system can generate electricity of 296,391 kWh/year with a renewable energy fraction reaching 79.9% and an electricity surplus of 0.988%.•Fuel consumption decreased by 79.3% compared to the existing Diesel Power Plant system.

A Hybrid Soft Sensor Model for Measuring the Oxygen Content in Boiler Flue Gas.

As an indispensable component of coal-fired power plants, boilers play a crucial role in converting water into high-pressure steam. The oxygen content in the flue gas is a crucial indicator, which indicates the state of combustion within the boiler. The oxygen content not only affects the thermal efficiency of the boiler and the energy utilization of the generator unit, but also has adverse impacts on the environment. Therefore, accurate measurement of the flue gas's oxygen content is of paramount importance in enhancing the energy utilization efficiency of coal-fired power plants and reducing the emissions of waste gas and pollutants. This study proposes a prediction model for the oxygen content in the flue gas that combines the whale optimization algorithm (WOA) and long short-term memory (LSTM) networks. Among them, the whale optimization algorithm (WOA) was used to optimize the learning rate, the number of hidden layers, and the regularization coefficients of the long short-term memory (LSTM). The data used in this study were obtained from a 350 MW power generation unit in a coal-fired power plant to validate the practicality and effectiveness of the proposed hybrid model. The simulation results demonstrated that the whale optimization algorithm-long short-term memory (WOA-LSTM) model achieved an MAE of 0.16493, an RMSE of 0.12712, an MAPE of 2.2254%, and an R2 value of 0.98664. The whale optimization algorithm-long short-term memory (WOA-LSTM) model demonstrated enhancements in accuracy compared with the least squares support vector machine (LSSVM), long short-term memory (LSTM), particle swarm optimization-least squares support vector machine (PSO-LSSVM), and particle swarm optimization-long short-term memory (PSO-LSTM), with improvements of 4.93%, 4.03%, 1.35%, and 0.49%, respectively. These results indicated that the proposed soft sensor model exhibited more accurate performance, which can meet practical requirements of coal-fired power plants.

Analysis Stability Of Asphalt Concrete Binder Course (AC-BC) With Fly Ash And Bottom Ash Substitution Material

Fly ash and bottom ash are ash produced from the process of burning coal as a source of energy in the steam generating unit of a coal-fired power plant (PLTU). Bottom ash is ash that forms at the bottom of a coal-burning furnace and settles there. In this research, fly ash is used as filler substitution and bottom ash is used as fine aggregate substitution (sand). The purpose of the study was to obtain a suitable Job Mix Design (JMD) for Asphalt Concrete - Binder Course (AC-BC) with fly ash and bottom ash substitution materials. To determine the effect of optimum asphalt content on the values of stability, flow, Marshall Quotient, VMA, VIM and VFB obtained from result of the Masrhall test. Based on the results of Marshall testing, the results show that Analysis Stability Of Binder Course Asphalt Concrete (AC-BC) With Fly Ash And Bottom Ash Substitution Material produces the highest VMA value of 14.462% and the highest VIM value of -1.88%, meaning that there are many gaps in the mixture containing asphalt so that it becomes waterproof and hermetic. The highest stability and MQ values are stability of 1955.55.34 kg and MQ of 1241.13 kg/mm. The appropriate Job Mix Design (JMD) for Asphalt Concrete - Binder Course (AC-BC) with fly ash and bottom ash substitution materials is the composition of Fly Ash at 0%, 50%, and 60% of the total cement while for the use of Bottom Ash from the total sand at 0%, 50%, and 60%.

Development of optimal operation algorithm for rotation mechanism of refuelling machine television rod

The paper examines the issues of optimizing the operation of the rotation mechanism of the television rod of the refuelling machine during the refueling campaign during the scheduled preventive maintenance at the NPP. The task under consideration is to minimize the time spent on turning the television rod during a reloading campaign in order to save time and money on technological operations, and thereby reduce the downtime of the nuclear power plant unit. A description of the design and purpose of the work area, the refuelling machine and other objects involved in technological operations is provided. In all parts of the working area there is a certain number of «problem» cells in which interference and/or blocking of rotation of the television rod may occur. The exact location of all «problem» cells and the permissible angles of movement and observation for them are revealed. The list of operations is compiled as a table containing: operation numbers, markings of the corresponding cluster, as well as the initial and target positions in coordinates. This table comes complete with a cartogram with coordinates and cell labels. It is calculated how long it takes to turn from one permissible viewing angle to another. An example of time calculation for an operation with a reloading machine is given.

Gas-particle flow induced erosion of economizer in low-low temperature electrostatic precipitators: Numerical prediction and engineering application

In this work, the gas-particle flow and the induced erosion in the economizer region in low-low temperature electrostatic precipitator were investigated by CFD-DPM-EPM coupling approach. The results show that positioning the economizer on the vertical flue or employing a vertical tubes arrangement for the heat exchange tubes, utilizing a small expansion angle (less than 35°) in the expansion section, ensuring a more uniform distribution of inlet gas velocity and dust concentration, and incorporating short and densely positioned guide plates in the expansion section can effectively reduce erosion in the low-temperature economizer. The above results were applied to the economizer equipped with the low-low temperature electrostatic precipitator of a 1000 MW unit in a certain power plant, and the wear situation was significantly improved. The research findings can serve as a reference for diagnosing and analyzing erosion phenomena in low-temperature economizer, and can guide the improvement design to prevent erosion.

ISSUES OF WATER USE IN THERMAL POWER PLANTS. PROBLEMS AND SOLUTIONS

The article considers the most effective methods of water treatment for thermal power plants. Water treatment is one of the most important processes in the operation of thermal power plants (TPP). The quality of water treatment for use in boiler units of thermal power plants is of fundamental importance to ensure the efficiency and durability of process equipment. This article reviews the main aspects of water treatment in TPP plants, including treatment methods, water quality characteristics and standards, and the impact of water treatment on the overall energy efficiency and safety of power generation in TPP plants.

Optimization of Injection Source Settings for SNCR Numerical Simulation of Low-Water Content Biomass Boilers with Blending.

In order to control NOx emissions and meet China's ultralow emission standards, a numerical simulation based on the computational fluid dynamics (CFD) approach is performed for the optimization of the reductant injection volume, number of injection sources, distribution, and injection direction for the flue gas denitrification process of a circulating fluidized bed boiler (CFB) blended with low-water content biomass in a 168 MW unit of a thermal power plant. Using the target power plant boiler entity as a template, a simplified geometric model is established, 1:1, and the mass fractions of each flue gas component set by the inlet boundary conditions are O22, H2O11.6, CO216.2%, and NO0.05%(about 134 ppm), and the reduction reactions under different optimized conditions are numerically simulated using the SNCR model in ANSYS Fluent 2021 R1. The simulation results under each condition were analyzed. The results show that the optimal ammonia-to-nitrogen ratio should be taken as NSR = 1.25, the denitrification efficiencies of 81.00, 81.63, and 82.74% at the three outlets are high, and the ammonia escapes of 1.76, 2.08, and 9.42 mg/s are within a reasonable range; increasing the number of injection sources can significantly reduce the disturbance of the flue gas flow field by reductant injection; the direction of injection is parallel to the direction of the flue gas flow, and the line of the injection source is orthogonal to the direction of the flue gas flow, which is conducive to the mixing of the reductant and flue gas; the optimized boiler denitrification efficiency reaches 74.2%, meeting the ultralow emission requirements of nitrogen oxides and ammonia escape.

Plant Information Management System Using OSIsoft PI System: A Case Study of Cilacap Power Plant Units 1 and 2

In the dynamic industrial sector, the ability to combine and manage data from various sources is essential. This study focuses on the utilization of the PI System to integrate operational data from multiple data sources at power plants, facilitating data driven decision making and enhancing operational efficiency. The application of the PI System in collecting data from Distributed Control Systems (DCS) and asset management systems like Maximo is examined, as well as its potential for integrating data from other power plant units. The study utilizes systems analysis methods to understand the potential of data integration in improving operational visibility and control. Findings from testing reveal that effective data integration can extend monitoring and management capabilities, indicating an overall improvement in operational performance. This study contributes to the literature on industrial data management by demonstrating the effective use of the PI System as a comprehensive tool for integrating data from various systems within power plants. It showcases the system's adaptability in enhancing operational decision-making and providing a cohesive platform for real-time performance monitoring. Additionally, the research offers insights into the practical application of systems analysis methods in the context of power plant operations, contributing to the ongoing discourse on digital transformation in the energy sector.

Influence of the type of woody biomass on energy and environmental characteristics of the thermal preparation processes and ignition of bio-water-coal fuel particles

The article presents the results of studies of ignition and combustion processes of droplets (during the initial period of heating), and then particles (after drying the surface layer) of bio-water-coal fuel (Bio-WCF) under conditions corresponding to typical furnace spaces of boiler units of thermal power plants (TPPs). The ignition delay times for Bio-WCF droplets of typical (for modern spray devices) sizes (diameter d=3 mm) have been established. The component compositions of the combustion products of significantly inhomogeneous bio-water-coal suspensions have also been established in a wide range of variations in the temperature of the oxidizing medium. A large-scale analysis of the influence of the type and concentration of woody biomass in a bio-water-coal suspension on energy (ignition delay time of WCF) and environmental (intensity of formation of anthropogenic combustion products of fuel) characteristics was carried out. It is shown that the addition of woody biomass to the water-coal suspension leads to a significant acceleration (by 10–20%) of the ignition process. An analysis of the component composition of combustion products showed that the introduction of wood biomass into the composition of water-coal fuel leads to a decrease in the intensity of the formation of anthropogenic combustion products. It has been established that an increase in the concentration of the vegetable component of the fuel leads to a significant sequestration of sulfur and nitrogen oxides.

Development and Research of non-alkali FGD Gypsum Products

The set-up of desulphurization units in domestic coal-fired power plants has brought increasing output of FGD gypsum, which results in a wide application of FGD gypsum products. During the application of such products, people found that they are prone to alkalization, i.e., a phenomenon significantly affecting the appearance and performance of the products. In this study, fly ash, another kind of waste from coal-fired power plants, was introduced to inhibit the alkalization of FGD gypsum products under the action of the alkali-activator for better utilization of waste resources.

Use of the Power Line Communication System (PLC) at Low Voltage (0.4 kV) Noisy Electrical Networks – Introducing a New Concept at Power Quality

Micro grids, smart grids, small power plants in range of household size stay in the lime-light. Nowadays, smart metering system stays directly before installation. All of the above mentioned systems require complex and discrete concepts and knowledge. Definitions and use of the right concepts and correct knowledge belong to actual questions of energetics. Small size distributed power plant units, drivers, controllers and switches belong to the power plants connecting to power grids can introduce high-frequency noises. In this work the spectra and the impact of the high-frequency noises have been investigated. After analysing the measured spectra followings can be declared: High-frequency noises can trouble the Power Line Communication (PLC) system at smart metering systems. Noise can destroy propagating parameters of the useful signal affecting the safety of data communication.

A Fault Detection Framework Based on Data-Driven Digital Shadows

Abstract The popularization of Industry 4.0 and its technological pillars has allowed prognostics and health management (PHM) strategies to be applied in complex systems to optimize their performance and extend their useful life by taking advantage of a digitalized, integrated environment. Due to this context, the use of digital twins and digital shadows, which are virtual representations of physical systems that provide real-time monitoring and analysis of the health and performance of the system, has been increasingly used in the application of fault detection, a key component of PHM. Taking that into consideration, this work proposes a framework for fault detection in engineering systems based on the construction and application of a digital shadow. This digital shadow is based on a digital model composed of a system of equations and a continuous, real-time communication process with a supervisory control and data acquisition (SCADA) system. The digital model is generated using monitoring data from the system under study. The proposed method was applied in two case studies, one based on synthetic data and another that uses a simulated database of an operational generating unit of a hydro-electric power plant. The method, in both case studies, was able to detect faults accurately and effectively. Besides, the method provides by-products that can be used in the future in other applications, helping with the PHM in other aspects.

Integrated Use of Expert Systems and Dynamic Models in the Intellectualized Operator Information Support System for NPP

The paper presents an approach for the integrated use of expert systems and dynamic models in an intellectualized operator information support system (IOISS) for power units (PU) of nuclear power plants (NPP). The main functions of IOISS for operators of NPP PUs are identified, and the full-scale implementation of these functions based on predictive dynamic modeling of PU parameters and the use of expert systems is shown. The structure of the expert system, which is part of the IOISS operators, is considered. This approach to the IOISS of operators is used in developing upper level systems for instrumentation and control (I&C) systems for NPPs.

Large-scale offshore wind energy integration by wind-thermal bundled power system: A case study of Yangxi, China

A large-scale offshore wind power integration has a reverse peak regulation effect on the electric load and requires newly built transmission corridors. This work adopts a wind-thermal (WT) bundled system for offshore wind power integration and transmission line capacity factor improvement. The Qingzhou I-VII offshore wind farms (5000 MW) and the Yangxi coal-fired power plant units #5, #6 (2 × 1240 MW) are taken as a case study. The offshore wind farms (OWF) act as the must-take generator to increase the renewable fraction while the thermal power plants (TPP) provide peak regulation service to trace the changing net load. The OWF and TPP share the transmission line and point of interconnection. The OWF integration level is determined by the 8760-h production simulation and the wind-thermal (W-T) capacity ratio is 1.4516:1 (3600 MW OWF) in the studied site. The curtailment rate, electricity shortage rate, transmission line capacity factor (CF), load following precision, renewable fraction, CO2 emission of WT-W3600 condition are 9.02%, 5.41%, 61.36%, 91.43%, 50.46%, 6.97 million ton/year. There is a trade-off relationship between renewable fraction and curtailment rate in the WT system which restricts higher OWF integration. The demand-side response technologies such as power-to-X and energy storage are required to break the trade-off relation and reduce the electricity shortage rate. The WT system is economically viable and the net present value (NPV), levelized cost of electricity (LCOE), internal rate of return (IRR) of WT-W3600 are 3.55 billion¥, 0.4859¥/kWh, 4.82%. Co-locating the OWF and the floating solar photovoltaic (PV) is the future direction that benefits the intensive exploitation of sea area and offshore renewable energy development.

Efficiency Analysis of the Third Unit in Al-Khoums Steam Power Plant, Libya

The thermal and overall efficiency of the third unit in the Al-Khoums steam power plant were investigated in this paper. Two samples of data have been used: the first was collected from the start-up data sheet of the power plant with a load of 120 MWH, and the second was collected in June 2023 with a load of 96 MWH. This study reveals that the thermal efficiency of the unit decreased by 9.4% (from 40.4% to 36.6%) due to the life of the plant and the stoppage of extraction lines, and the overall efficiency decreased by 8.7% (from 36.7% to 33.5%). Moreover, heat rejected by the condenser increased in the second sample by 44 kJ/kg. Steam cycles for both study samples were presented by T-S diagrams using Engineering Equation Solver software (EES), and it was clear from those diagrams that the efficiency of the high-pressure turbine in the first sample is higher than the second one.

Evaluation and Optimization Based on Exergy in Kamojang Geothermal Power Plant Unit 3

The quality of production well from the Kamojang geothermal power plant unit 3 diminishes annually, whereas there has been a substantial rise in the demand for electrical energy in the region. This research focuses on optimizing the vacuum pressure in the main condenser by employing exergy analysis, a methodology grounded in the principles of the second law of thermodynamics. Exergy analysis offers insights into each system component's exergy efficiency and irreversibility. Furthermore, an energy assessment is conducted to offer insights into each component's energy consumption or utilization. Energy and exergy rates are computed for every state and component within the power plant, encompassing the steam receiving header, separator, demister, turbine, main condenser, inter condenser, after condenser, and cooling tower. The exergy analysis findings reveal that the exergy rate derived from the production well amounts to 95327 kW, generating 52882 kW of electricity and producing a system exergy efficiency of 55.47%. The turbine experiences the highest irreversibility, totaling 12874 kW. Adjustments are made to the main condenser vacuum pressure to optimize the system, aiming to identify the optimal setting that maximizes both exergy efficiency and power output. The optimization outcomes indicate that reducing the vacuum pressure in the main condenser leads to enhanced exergy efficiency and increased power output. The optimal vacuum pressure obtained is 0.1 bar, resulting in the highest exergy efficiency and output power of 57.42% and 54738 kW, respectively, with the lowest irreversibility of 32751.07 kW.

Evaluation and Optimization Based on Exergy in Kamojang Geothermal Power Plant Unit 3

The quality of production well from the Kamojang geothermal power plant unit 3 diminishes annually, whereas there has been a substantial rise in the demand for electrical energy in the region. This research focuses on optimizing the vacuum pressure in the main condenser by employing exergy analysis, a methodology grounded in the principles of the second law of thermodynamics. Exergy analysis offers insights into each system component's exergy efficiency and irreversibility. Furthermore, an energy assessment is conducted to offer insights into each component's energy consumption or utilization. Energy and exergy rates are computed for every state and component within the power plant, encompassing the steam receiving header, separator, demister, turbine, main condenser, inter condenser, after condenser, and cooling tower. The exergy analysis findings reveal that the exergy rate derived from the production well amounts to 95327 kW, generating 52882 kW of electricity and producing a system exergy efficiency of 55.47%. The turbine experiences the highest irreversibility, totaling 12874 kW. Adjustments are made to the main condenser vacuum pressure to optimize the system, aiming to identify the optimal setting that maximizes both exergy efficiency and power output. The optimization outcomes indicate that reducing the vacuum pressure in the main condenser leads to enhanced exergy efficiency and increased power output. The optimal vacuum pressure obtained is 0.1 bar, resulting in the highest exergy efficiency and output power of 57.42% and 54738 kW, respectively, with the lowest irreversibility of 32751.07 kW.

Composite reliability evaluation of Integrated Nepal Power System

Abstract the worth of reliability has been increasing with the advancement of technology. Based on the involvement of the various functional zones, the assessment of the reliability of the power system is divided into 3 Hierarchy levels (HL). The composite reliability (HL II) involves the availability of generation systems and transmission systems in evaluating the reliability of power systems. In this paper, the composite reliability of the Integrated Nepal Power System (INPS) is assessed using sequential Monte Carlo Simulation (MCS). Based on the trip data of the various Hydro Electric Power Plant (HEPP) units of Nepal and of transmission line, the artificial UP and DOWN sequence of the composite system is simulated. The power output of the Hydro-Electric Power Plant (HEPP) is varied based on the variation of seasonal flow. The system state is compared with the hourly load data of various load centers of INPS to determine the reliability indices like LOLP, LOLE, and EENS. As the eastern part of INPS doesn’t have a generating unit, it is found to have lower reliability. The reliability of INPS can be improved by improving the reliability of load centers that have a lower value of reliability indices.

Optimization of load frequency control using grey wolf optimizer in micro hydro power plants

Micro hydro power plants (MHPP) is one of the renewable energy that can be utilized as a distributed generation with controllable power output. One common issue in MHPP systems is the non-constant rotation of the generator caused by load fluctuations. This instability leads to variable frequencies, which can potentially harm electrical equipment. To address this problem, the volume of water entering through the governor can be adjusted to synchronize the turbine and generator rotation with the load. This approach helps dampen frequency oscillations and ensures that the system operates within desired limits. Therefore, there is a need for technology that can enhance the performance of micro hydro power plant units, specifically load frequency control (LFC). This research proposes the application of the grey wolf optimizer (GWO) algorithm to optimize the PID controller parameters for MHPP LFC. MHPP has been modeled in both isolated and grid-connected modes using Simulink MATLAB R2020a. The best cost function value for an isolated mode system was obtained with ISEim, yielding a value of 0.067653, while for a grid-connected mode system, it was achieved with ISEgm, with a value of 0.015861. The results of the frequency deviation response performance of the LFC using GWO indicate that the fastest settling time was achieved with the cost function ITAEim in isolated mode, and with IAEgm in grid-connected mode. The cost function that produces the smallest peak overshoot and peak undershoot parameter values varied depending on changes in the system load.