Steam Turbine Power Plant Research Articles

Further Improvement of the Mathematical Model of Thermo and Gas-Dynamic Processes in a Turbine without Working Blades of Some Stages

The current state of the Ukrainian power system is characterized by significant stress and a shortage of generating capacities. Restoration and implementation of new generating capacities require a huge amount of appropriate resources and a lot of time. The optimal low-cost and relatively fast option for improving the state of the power system may be the temporary use of damaged power equipment after taking appropriate preventive and repair measures. The emergency state of steam turbines of many power plants requires a special tool for assessing their efficiency and power, as well as the possibility and feasibility of their further use after damage. This paper gives consideration to an improved mathematical model of thermo and gas-dynamic processes in a turbine without working blades of some stages. The test calculation data obtained for the flow parts of the cylinders of various steam turbines in the absence of working blades were presented both for individual stages and the groups of stages. Characteristic patterns of the effect of the location of the stage without working blades in the turbine cylinder on the efficiency of the flow part have been established. The greatest decrease in the efficiency and power of the cylinder occurs in the case of the absence of working blades in the stages located closer to the cylinder head. The lowest efficiency and power losses are observed in the absence of working blades of the last stage. In the nozzle cascades of the stages located directly behind the stages without working blades, the levels of energy losses are increased significantly. The use of the developed mathematical model allows us to find solutions to increase the efficiency of turbines with missing working blades in some stages by changing the geometry of the appropriate nozzle cascades.

Numerical investigation and optimization of heterogeneous-homogeneous coupled condensation in steam turbines of tower solar power system

The significant potential for stage efficiency improvement is in steam turbines of solar thermal power plants, which operate in difficult atmospheric conditions contributing to the high pressure in the condenser and steam impurities. Presented study aims to examine the influence of three steam impurities on the condensing flow through turbine stage rotor. Firstly, the modified condensation model is validated using experimental data. Next, the flow characteristics and losses of pure steam and steam containing heterogeneous particles in three-dimensional turbine are investigated separately, and the effects of particles on the flow process and system performance are analyzed. Finally, the effect of backpressure on the condensation flow and the turbine performance is investigated. The results reveal that homogeneous condensation predominantly occurs at higher blade height, NaCl particles have the most significant impact on condensation. At a particle concentration of 10151/kg, the thermal efficiency of heterogeneous condensation on solid particles and tiny droplets increases by 1.6 % and 2.3 %, respectively, compared to homogeneous condensation. Conversely, NaCl particles exhibit a reduction of 0.2 %. Lastly, by strategically raising the backpressure, it is feasible to decrease the humidity on the final stage blades, enhancing thermal efficiency and ultimately optimizing tower solar power generation system operation.

Electromagnetic–thermal–mechanical coupling analysis of bent rotor straightening via electromagnetic induction heating

Abstract Rotors of steam turbines in power plants can be locally deformed by undesired situations, such as rubbing between the rotors and stationary parts. A straightening process is required to correct bending without causing additional damage because a rotor bending displacement of approximately 0.15 mm can stop turbine unit operation. In this study, a numerical framework was established to simulate the straightening process using electromagnetic induction heating, which is straightforward and economical among the methods for straightening bent rotors. The straightening process involves complex coupling of electromagnetic, thermal, and mechanical phenomena. For efficiency, sequential coupling was used in the simulations, dividing the multiphysics phenomena into electromagnetic–thermal and thermal–mechanical fields. The temperature distributions resulting from electromagnetic induction heating were calculated through two-way coupling of the electromagnetic–thermal analysis. The thermal deformations of the rotors were obtained by solving the coupled equations for the thermal field obtained from the electromagnetic–thermal analysis and the mechanical field. Using the established numerical framework, the thermal–mechanical behaviors and straightening mechanisms of bent rotors were investigated. Furthermore, the effects of process parameters, including the direction of gravity and heating and cooling conditions, on the straightening performance were determined. Appropriate parameters were identified to achieve the desired straightening performance with final bending displacements of less than 0.1 mm for bent rotors with initial bending displacements of 0.15–0.3 mm. For a rotor made of A182 F11 Class 2, the best straightening performance was obtained by heating the rotor to a maximum temperature of 650 °C for 20 h under insulation, followed by natural cooling. The simulation results revealed that the straightening performance can be improved when the rotor is rapidly heated to a high maximum temperature and cooled immediately, as long as the temperature conditions do not cause phase transformation or unintended plastic deformation of the bent rotors.

Exergoeconomic analysis of a steam turbine power plant in a sulfuric acid factory

This study presents an exergoeconomic analysis of a steam turbine power plant (STPP) implemented within a sulfuric acid production facility. The plant harnesses waste heat from an exothermic chemical reaction to generate electricity. A detailed mathematical model was developed in Engineering Equation Solver (EES) to perform the exergoeconomic assessment on individual components and the overall system.The STPP generates 4.7 MW of electricity, with an exergoeconomic factor of 33 %. The exergy cost and unit exergy cost of the electricity are 455.8 $/h and 26.94 $/GW, respectively. The turbine represents the highest capital cost within the system. The steam produced incurs an exergy cost of 640.7 $/h, with a unit exergy cost of 2.2 $/GW. The waste heat boiler exhibits the highest exergy destruction cost at 112 $/h, and the major exergy destruction cost ratios are observed for the waste heat boiler (0.23 W/$) and the turbine (0.51 W/$). Additionally, the impact of variations in steam inlet temperature and pressure on the exergoeconomic performance was analyzed.These findings provide valuable, cost-based indicators such as exergy destruction cost, exergoeconomic factor, and exergy destruction cost ratio, which can guide the optimization and practical implementation of STPPs in the sulfuric acid industry.

COMBUSTION OF HYDROGEN IN OXYGEN-STEAM MIXTURE FOR INCREASING THE STEAM TEMPERATURE OF POWER PLANTS

In the work the problems that arise at combustion of hydrogen in oxygen-steam mixture for the purpose of combustion products (steam) mixing for heating steam, which is planned to be used in steam turbines of power plants were researched. The main problem is the formation of underburning H2 and, accordingly, the presence of O2, which have a negative effect on metals, and it will also prevent steam condensation in the condenser was determined. For solve this problem, calculations of the equilibrium concentrations of chemical reaction products in the combustion zone depending on the amount of ballast steam added to the oxidizer (oxygen) for the initial conditions: T0=528 K, p=0.1 MPa; T0=​​528 K, p=3.1 MPa; T0=​​584 K, p=10 MPa were made. The corresponding adiabatic temperatures were calculated. The dilution of the oxidant (oxygen) with steam significantly decreases the adiabatic temperature (Tb) and reduces the equilibrium concentrations of other substances in the combustion zone, but at the same time the laminar flame propagation velocity (SL) also significantly decreases was established. It is important when a certain concertation of ballast steam is achieved (the final percentage is determined by the design of the burner) there will be a sharp deterioration of combustion or even the formation of a flame will be impossible. The principal design of the hydrogen-oxygen-steam combustion chamber was proposed. The necessity of heating oxygen and hydrogen and the principle of determining the pressure under which it is advisable to supply oxygen and hydrogen to ensure the maximum intensification of mixing first of oxygen and steam, and then of the formed mixture and hydrogen, were substantiated. Bibl. 20, Fig. 5, Table 3.

Influence of oscillatory hydromagnetic field with mixed convection driven Sutterby nanofluid flow over a stretching cylinder

A nonlinear mixed convective sutterby nanofluid flow along a stretching cylinder is being studied in this article. The set of partial differential equations (PDEs) that control fluid flow is nonlinear and subject to surface constraints and similarity transformation reduces a system of PDEs to non-dimensional ordinary differential equations (ODEs), which are then solved in MATLAB Bvp5c solver which is based on the Runge–Kutta method and Shooting technique. We provide a graphic evaluation of the significant contributions made by the various physical terms to engineering measurements in the curiosity and transport domains. The study discovers that temperature distribution increases heat border viscosity but reduces thermal diffusion, whereas nonlinear convection heat improves surface heat transfer. The periodic magnetic field raises the fluid temperature while decreasing the rate of energy transfer. Furthermore, experiments have demonstrated that oscillating magnetic fields induce fluctuations with a sinusoidal pattern. Furthermore, the current study has applications in the design and manufacture of cylinder-shaped objects in various fields such as aerospace engineering, geophysics, and nuclear engineering. These include core catchers in nuclear power plant steam turbines, waxy crude oils or foodstuffs in centrifugal pumps, and deformation rates that frequently occur in practical turbomachinery and other industrial processes.

Managing a Major Lube Oil Leak on a 150 MW Steam Turbine Power Plant

This paper focuses on the management of a major lube oil leak from bearing box No. 2 at the Sumsel-5 Power Plant. The steam turbine, a super high-pressure has been operational since April 2016. Overhauls in 2019 and 2023 addressed issues such as wear on oil deflectors, abnormal gland sealing clearances, and oil sealing wear. However, oil leakage persisted, necessitating further interventions. Rectification efforts included replacing oil deflectors, adjusting clearance, installing additional venting lines, the addition of a fiber gasket at bearing box No. 2 aimed to reduce and manage oil leakage. These measures resulted in a significant reduction in the oil leakage rate, from approximately 2826 ml/hr to 75 ml/hr during full load operation, representing a decrement of around 97.3%. Additionally, the frequency of lube oil top-ups decreased dramatically, leading to substantial cost savings for the plant. From a safety and environmental perspective, rectification measures mitigated fire hazards and reduced oil wastage, minimizing environmental impact. Regular monitoring of lubrication oil quality further ensures operational reliability. Although complete elimination of the oil leak was not achieved, the turbine continues to operate smoothly under manageable oil leakage conditions.

Thermal Hydraulic Analysis of Turbulent Flow of Superheated Steam Through Multiple Configurations of 3D Angular Piping Bend in Power Plant Installations

Abstract One of the most vulnerable parts in high-pressure and temperature pipeline networks in steam turbine power plant installations is pipe bends, due to intense fluctuation of velocity and pressure of the superheated steam flowing through the piping bend. On the other hand, because of unique chemical and physical properties, the transportation of superheated steam can adversely effect on the integrity of the pipe bends in the piping network. Therefore, the potential risk of pipeline failure becomes more probable at bends. Therefore, to ensure the survivability of the piping network, thorough investigations of the superheated steam flowing through pipe bends are of great significance in better understanding its flow behavior. However, to predict flow behavior at piping bend, intensive research by direct experiment at high temperature and pressure might not be possible to some extent. In that case, computer codes and models can help us analyze flow behavior of superheated steam at pipe bends. The current work is a computational fluid dynamics investigation, where numerical examination is carried out by commercial code ansys fluent for thermal hydraulic analysis of flow behavior of superheated steam through multiple configurations of 3D angular piping bend: 90 deg, 120 deg, and 135 deg. Validation of credibility of the computational approach is done against Sudo et al.'s experiment. With relatively good agreement between the experiment and numerical result using air flowing through 90 deg elbow, single-phase turbulent flow of superheated steam is examined by the application of realizable turbulence model (k–ɛ). The final assessment of the computed results has been done using qualitative and quantitative analyses. The study reveals that unlike the pressure profiles, the radial velocity profiles at the bend exit are noticeably different from those at the bend inlet, since they exhibit more rounded peaks and gentler velocity gradients. The study also shows that the radial pressure and velocity profiles do not display any sign of the existence of a pair of vortices.

Performance optimization of generator in steam turbine power plants using computational intelligence techniques

Performance optimization of generator in steam turbine power plants using computational intelligence techniques

Comparative study of steam, organic Rankine cycle and supercritical CO2 power plants integrated with residual municipal solid waste gasification for district heating and cooling

Among the different waste-to-energy solutions, gasification is considered a promising option and an alternative to landfilling of residual municipal solid waste (RMSW). Therefore, the potential of RMSW air gasification in combination with three different power cycles for district cooling and heating applications is investigated. The model of a fluidized bed air gasifier developed in Aspen Plus is integrated with the models of steam turbine (ST), organic Rankine cycle (ORC), and supercritical CO2 (sCO2) Brayton cycle power plants for the combined cooling, heating, and power production in district networks.The results of the numerical study show that the ST power plant provides higher electrical power compared to the other systems, while sCO2 exhibits better thermal power and the maxima combined energy conversion efficiency. In between, ORCs prove to be a reliable and flexible solution for varying RMSW compositions and temperature levels of the district network. The size of the district network strongly varies with scenarios and in the best case, more than 1,400 residential buildings can be connected to the trigeneration plant considering 20 ktons/year of RMSW input to the gasifier.

Hybrid gas and steam turbine power plant for FPSO vessel

Hybrid gas and steam turbine power plant for FPSO vessel

Failure analysis steam turbine in sugar factory thermal power plant: a Review

Generating electricity from thermal energy is one of the main ways of generating electricity. However, it must be generated in the most efficient and effective way. Due to the urgency of electricity generation, it is essential that it is produced in the most efficient way to minimize losses, maximise output, optimise resource utilisation and reduce overall costs of the power plant. These outputs are even more critical in the current era where sustainability has become the top priority. A thermal power plant is a converter of fossil fuels to electricity in which steam is used during a cycle to spin a turbine driving generator to produce electricity. It is important to maintain a power plant if it runs without failure. Reliability analysis is a standard tool for designing, scheduling and maintaining any system. Reliability of a power plant refers to the ability to generate electricity efficiently and more cost-effectively with an acceptable quality assurance. This paper provides an in-depth analysis of power generation in a sugar factory by steam turbine and the reasons for steam turbine failure. It also analyzes the maintenance models employed to enhance steam turbine availability in thermal power plants.

Thermodynamic analysis of an innovative steam turbine power plant with oxy-methane combustors

Thermodynamic analysis of an innovative steam turbine power plant with oxy-methane combustors

The Effect of The L/G Ratio on SO2 Removal Efficiency in Seawater Absorption Columns

Steam Turbine Power Plants are widely known as one of the primary sources of electricity generation, utilizing coal combustion. However, this process leads to the emission of air pollutants, including sulfur dioxide (SO2), which is considered harmful. To mitigate this issue, Seawater Flue Gas Desulfurization (SWFGD) has been implemented as a control device to reduce the concentration of SO2. Previous studies on SWFGD have mainly focused on operational factors such as gas flow rate and liquid flow rate using artificial seawater as the absorbent. However, there is a lack of research on utilizing natural seawater, particularly from Indonesia, as the absorbent. Hence, this study aims to determine the efficiency of SO2 removal using Indonesia's natural seawater and investigate the influence of varying the L/G (liquid-to-gas) ratio on the overall removal efficiency. The study employed a packed tower reactor with a counter-current flow configuration. The gas concentration of SO2 used in this study is 1500 ppm, which is adjusted to match the existing conditions in the Steam Turbine Power Plant. The variations in seawater flow rate range from 150 to 250 liters/hour, while the variations in gas flow rate range from 1 to 10 m3/hour at 30oC. So, the L/G ratio value is within the range of 20.9 to 104.5. The results indicated that an increase in the L/G ratio corresponded to an increase in the total removal efficiency. The highest achieved efficiency reached 98.5%, while the lowest efficiency recorded was 84%.

A novel concept to improve the flexibility of steam power plants using an electric feedwater heater

The concepts of operational flexibility enhancement for steam turbine power plants described in the trade literature focus on thermal energy accumulation and utilization. In this paper a new concept of flexibility improvement is presented for steam turbine power plants, using an electric heater to preheat the feedwater for the boiler. The proposed method does not require extensive alterations in the power plant process systems, and no large thermal energy storage is necessary. It is important to note that this solution is only applicable if the boiler and its control system have the capability to work under this reduced load condition. By using electric feedwater heating it is possible to reduce the power transferred to the grid and keep the plant in operation at low loads. Thanks to the developed model of a 200 MW reference power plant using the Ebsilon Professional 15 software, the authors carried out simulation tests, based on which it has been proven that it is possible to reduce the minimum load for grid production from 92 MW to 78 MW. Although the efficiency of the electricity production decreased, the cost analysis has shown that the proposed modifications are reasonable, thanks to the improved cooperation of the 200 MW power plant with the grid. The NPV in the analysed system was PLN 35 million, and the sensitivity analysis showed that the profitability will increase with the increased number of necessary shutdowns of power plants without modifications. This is particularly important considering the development of renewable energy sources and the random and stochastic nature of their electricity generation.

Expert Knowledge Transfer from CAE Models to CNN Models Using Enhanced Adversarial Domain Adaptation

It is a common belief that convolutional neural networks (CNN) are incapable of acquiring knowledge from domain experts for fault detection and diagnosis. To address the challenge, this paper proposes a knowledge-transfer scheme from computer-aided engineering (CAE) models to CNN models. Domain experts build the CAE models that emulate the faulty behavior of rotating machines by incorporating fault symptom and controlling the degree of fault severity. Fault data are hardly acquired from rotating machines in the field, while a sufficient number of fault data can be generated using the CAE models. Then, a domain adaption model is trained using synthetic data (i.e., normal and fault data) from the CAE models and real data (i.e., normal data only) from rotating machines. To evaluate the validity of the proposed method, a small-scale testbed is regarded as the target system that does not have any fault data. This study contributes to resolve the dearth of fault data from most safety-related engineering assets such as power plant steam turbines, wind turbines, and urban air mobility.

Study on Fracture Mechanism of Low-Pressure Blades of Steam Turbines in Power Plants

With the continuous improvement of steam turbine design technology and production level, steam turbine blade fracture accidents have dropped significantly, and blade fracture accidents are no longer the main reason for the forced shutdown of thermal power generation units. Due to the bad working conditions of turbine blades, blade designers still need help to accurately analyze their dynamic stress and evaluate their high cycle fatigue life. Up to now, blade fracture accidents still occur frequently. In this paper, a comprehensive analysis is made of the causes of the fracture of the low-pressure 16th stage blade of a 25 MW steam turbine in a thermal power plant. The fracture property of turbine moving blades is that small corrosion pits are formed first, and then the fatigue propagation fracture occurs. The main cause of corrosion is poor steam quality.

Condition Evaluation of Steam Turbine Generator Using Minute-Interval Integrated Vibration Signals

Vibration levels are a primary indicator for condition monitoring of Electrical Machine (EM) systems. This work employs Singular Spectrum Analysis (SSA) to analyze vibration time series of shaft and bearings of a real 250MW industrial power plant steam turbine Synchronous Generator (SG) in Greece. The SG operates under reduced power due to increased vibration conditions according to threshold guidelines. This work attempts to retrieve fault indications from the minute-interval integrated signal sample via its trend and periodicity components to predict vibrations under full load operation and establish correlations to discern whether the reduced output is justified. The successful application of this novel procedure is important due to ease of storing and handling low frequency signals, especially in remote environments. Rules are established using fuzzy logic due to the nature of the dataset and industrial application. The predictor employed is based on Sugeno-based Adaptive Neuro Fuzzy Inference System (ANFIS).

Analysis and Comparison of Main Steam Turbines from Four Different Thermal Power Plants

This paper presents an analysis and comparison of four steam turbines and their cylinders from four different power plants (marine, conventional, ultra-supercritical and nuclear power plants). The main goal was to find which steam turbine and their cylinders show the best performances, the highest efficiencies, the lowest specific steam consumption and which turbine is the lowest influenced by the ambient temperature change. The highest efficiencies, both isentropic and exergy, are observed in the steam turbine and their cylinders from the ultra-supercritical power plant (whole turbine from ultra-supercritical power plant has an isentropic efficiency equal to 88.36% and exergy efficiency equal to 91.05%). Also, this turbine has the lowest specific steam consumption (7.32 kg/kWh) and exergy parameters of this turbine are the lowest influenced by the ambient temperature change. The worst performance (the lowest efficiencies, high specific steam consumption and the highest sensitivity to the ambient temperature change) show the cylinders and whole turbine from marine propulsion power plant. The same analysis and comparison are also performed for several other steam turbines from four mentioned power plants, so the presented relations and dominant conclusions have general validity. It can be concluded that steam turbines in ultra-supercritical power plants show the best performances in comparison to steam turbines from any other power plant.

Mixed convective magnetized GO‐MoS2/H2O hybrid nanofluid flow about a permeable rotating disk

AbstractThe primary objective of the present numerical analysis is to investigate the effect of a mixed convection flow around a disk containing hybrid nanofluid as graphene oxide (GO)‐molybdenum disulfide (MoS2) nanoparticles and water (H2O). This study examines the impacts of surface suction/injection, slip effect, magnetohydrodynamic effect, the shape of nanoparticles, and heat transfer characteristics, on a disk is analyzed. This research applies to disk‐shaped structures in aeronautical engineering, geophysics, and nuclear engineering, such as core catchers in nuclear power plant steam turbines, waxy crude oils or food products in centrifugal pumps, turbo‐machinery, and other industrial processes. Nonlinear partial differential equations (PDEs) with subjected surface restrictions represent this study's governing equations. It's a PDE. The Von Karman transformation can simplify PDEs into non‐dimensional ordinary differential equations, which can be solved using the MATLAB bvp5c function. The research findings indicate that the presence of hybrid nanoparticles results in a significant increase in the heat transfer rate compared to that of the nanoliquid. Increasing the strength of the magnetic field slows down the flow of a hybrid nanofluid. The gradient value pronounces impacts with increasing slip factor. The heat transfer rate increases significantly with the increase of sphericity of the nanoparticles.