Steam Turbine Power Plant Research Articles

Study on ultrasonic attenuation characteristics in air-droplet two-phase flow

The wetness of exhaust steam in nuclear power plant steam turbine is an important index to evaluate the safety and economy of nuclear power plant and the ultrasonic attenuation method has the advantages of quick response and non-contact in the steam wetness measurement of nuclear power plant steam turbine. The saturated steam-droplet medium and the air-droplet medium have many similar thermal fluid characteristics, in order to simplify the experiment, the air-droplet two-phase flow is used to simulate the wet steam discharged from steam turbine of nuclear power plant, and the ultrasonic attenuation coefficient in the air-droplet two-phase flow is measured. The correlation between wetness and ultrasonic attenuation coefficient was studied by calibrating the wetness of the air-droplet two-phase flow and measuring the ultrasonic attenuation coefficient under different wetness conditions. Meanwhile, the static characteristics of ultrasonic transducer and the influence of flow velocity on attenuation coefficient are studied experimentally. According to the results of experiment and numerical calculation, the ultrasonic attenuation coefficient is very sensitive to the change of wetness. The ultrasonic attenuation coefficient and wetness has a good linear relationship in the wetness range (0–16%), the ultrasonic attenuation method is appropriate for the wetness measurement of turbine steam exhaust and has high precision when the droplet size is stable.

Special issue on “Optimal design and operation of energy systems”

Special issue on “Optimal design and operation of energy systems”

Research on Technical supervision of Steam turbine in nuclear power plant

Based on the technical characteristics of nuclear power turbine, the technical differences between nuclear power turbine and thermal power turbine are analyzed. Based on the premise of nuclear safety and combined with the characteristics of nuclear power plants, the feasible supervision mechanism of conventional island turbine and the daily management responsibilities of nuclear power supervision are studied. Extensive research and collection of nuclear power related data, including technical specifications, operation procedures, maintenance procedures, etc., through the analysis and collation of these data, the technical supervision content of nuclear power conventional island turbine is studied, highlighting the differences with thermal power turbine technical supervision.

Life cycle cost and environmental assessment of CO2 utilization in the beverage industry: A natural gas-fired power plant equipped with post-combustion CO2 capture

Besat is a natural gas-fired steam-turbine power plant in Tehran, Iran’s only power station equipped with a monoethanolamine-based post-combustion CO2 capture unit (PCCU). The PCCU operates at a low recovery rate of 4.7% and produces 58 t-CO2/day. Captured CO2 is encapsulated and sold to beverage companies for carbonated soft drink production. Before developing this CO2 capture and utilization (CCU) route, a beverage company like ZamZam produced CO2 on-site, capturing CO2 from flue gas of diesel-fired boilers using a 95%-efficient absorption-refrigeration unit. This paper conducts an attributional, comparative life-cycle assessment/costing of applying the CCU technology to supply the beverage industry with CO2. ReCiPe, cumulative energy demand, and AWARE impact assessment methods are adopted to assess changes in the life-cycle economic, energy, and environmental impacts of electricity, liquid CO2, and carbonated water supply chains with the CCU route. As per findings, the CCU route significantly improves the sustainability profile of liquid CO2 supply for carbonated water production. Compared to on-site production, the CCU route reduces the average economic, energy, and environmental impacts of liquid CO2 supply by 55, 44, and 62%, respectively. However, the figures for carbonated-water production are reduced by only 10.1, 0.85, and 0.77%, respectively, since associated impacts primarily result from citric acid and polyethylene terephthalate value chains rather than liquid CO2. The CCU route, in comparison, increases most environmental burdens of electricity generation. With an efficiency of 4.7%, the PCCU reduces the global warming potential of electricity generation by 6.22% while increasing average toxicity- and eutrophication-related impacts by 55 and 30%, respectively, and production costs by 8%.

A Model for Managing the Lifecycle of Thermal Power Plant Steam Turbine Bearings Using Digital Technologies

The article discusses the problems of monitoring the condition of bearings, which are among the important components of steam turbine installations, the information about the lifecycle of which at thermal and nuclear power plants is currently not available almost completely. A model of an automated bearing lifecycle management system (ABLMS) based on digital technologies is presented, in which, according to the principles of interoperability, data come from all information systems involved in managing the component lifecycle at all its stages (designing, manufacture, operation, and repair). The use of this system at power industry enterprises will make it possible to set up stable information links between the developer's personnel (turbine manufacturing plants) and operating personnel, and enhance the quality of equipment and its competitiveness.

Discussion on Reasonable Utilization of Heat Energy by Heat Exchange Equipment of Steam Turbine in Power Plant

Discussion on Reasonable Utilization of Heat Energy by Heat Exchange Equipment of Steam Turbine in Power Plant

Myths about Lack of Competitiveness of Combined Electricity and Heat Production by Combined Heat and Power Plant Steam Turbine Units in Comparison with the Best Available Technology of Their Separate Production

Myths about Lack of Competitiveness of Combined Electricity and Heat Production by Combined Heat and Power Plant Steam Turbine Units in Comparison with the Best Available Technology of Their Separate Production

Methods for Competitiveness Improvement of High-Temperature Steam Turbine Power Plants

The paper is concerned with the problem of the development of high-temperature steam turbine power plants with ultra-supercritical (USC) initial parameters. One of the main disadvantages of the USC power unit’s creation is high price due to the application of expensive heat-resistant materials for boiler, live and reheat steam pipelines in turbines. To solve this problem, the following technical improvements to reduce the application of the heat-resistant materials and equipment metal consumption are proposed: horizontal boiler layout, high temperature steam turbine with a cooling system, oxy-hydrogen combustion chambers, and two-tier low-pressure turbine. The influence of the above-mentioned solutions on the high-temperature steam turbine power plant efficiency was estimated using thermodynamic analysis. The promising equipment design was developed based on the results of numerical and experimental research. The analysis of the proposed solutions’ influence upon the economic parameters of a high-temperature power facility was investigated based on the developed cost analysis model, which included the equipment metal and manufacturing expenses. The introduction of all the mentioned cost reduction methods led to a decrease in the facility’s price by RUB 10.5 billion or 15%. The discounted payback period was reduced from 27.5 to 10 years and the net present value increased by RUB 9.6 billion or 16 times.

Stochastic modeling and availability optimization of condenser used in steam turbine power plants using GA and PSO

AbstractThe prominent objective of the present study is to optimize the availability of condenser units in steam turbine power plants. For this purpose, a novel stochastic model is proposed by considering a condenser as a system consisting of seven subsystems. All the time‐dependent random variables associated with failure rates followed exponential distribution while repair rates are arbitrarily distributed. Furthermore, to attain the optimum value of system availability nature‐inspired algorithm has been applied. Predicting the future phenomena is very difficult and most of the existing algorithms have some limitations like stuck at local minima, and slow convergence rate, and so forth. So, in this study proposed model has been optimized using a genetic algorithm (GA) and particle swarm optimization (PSO)The expressions for steady‐state availability of the system have been assessed using Chapman‐Kolmogorov differential‐difference equations developed by applying the Markov birth‐death process. The supplementary variable technique has been adopted to solve differential‐difference equationsFor a comparative analysis, the steady‐state values, GA, and PSO results are compared. It is revealed that the GA gives the maximum value of availability as 0.9886 corresponding to crossover probability 0.65, population size 50, evaluation 300, and mutation probability 0.5. While using PSO optimum availability value is 0.998152 at 27 iterations, population 55, inertia weight 1, damping ratio 0.85, personal best 1.5, and global best 2. So, PSO results outperform the steady‐state and GA results. It is revealed that mixed bed filter and ejector are the most sensitive components of the condenser those influences most the system effectiveness.

Discussion on Application of Energy-saving Technology in Operation of Steam Turbine in Power Plant

Discussion on Application of Energy-saving Technology in Operation of Steam Turbine in Power Plant

Efficient Stochastic Model for Operational Availability Optimization of Cooling Tower Using Metaheuristic Algorithms

Metaheuristic algorithms are extensively utilized to find solutions and optimize complex industrial systems’ performance. In this paper, metaheuristic algorithms are utilized to predict the optimum value of the operational availability of a cooling tower in a steam turbine power plant. These techniques have some flaws like poor convergence speed, being stuck in local optima, and premature convergence. For this purpose, a novel efficient stochastic model is proposed for a cooling tower that is configured with six subsystems. The Markovian birth-death process is utilized to develop the Chapman-Kolmogorov differential-difference equations. All the random variables are statically independent, and repairs are perfect. Failure rates are exponentially distributed, while repair rates follow the arbitrary distribution. Steady-state availability (SSA) of the system is derived concerning various failure and repair rates. The sensitivity analysis of SSA is also performed to identify the most critical component. Further, system availability is optimized using genetic algorithm (GA) and particle swarm optimization (PSO) because they are found to be more suitable for such types of problems. It is revealed that the PSO outperforms GA in predicting the availability of cooling towers used in steam turbine power plants.

Integration of MHD System to The Gas Turbine and The Steam Turbine Power Plant: A Brief Review

Electrical energy generation is essential for the survival of the modern society. Fossil fuels are limited and create pollution. Also the conventional power generation systems using fossil fuel have lesser efficiency due to higher amount of losses in different sections of the plants. The Magnetohydrodynamic (MHD) is found as a nonconventional energy generation system which has the capability to enhance the thermal power plant efficiency significantly. The MHD is a direct energy conversion system that describes the interactions of a magnetic field and an electrically conductive fluid to produce electrical power. The system is simple and it avoids the difficulty of choosing a rotating turbine or engine and massive number of complex calculations. The high temperature tolerable materials can be used in the system due to the exponential development of material science. In MHD system, energy of plasma or ionized gas is directly converted into electric power. The conversion process of the system is based on the principle of Faraday’s Laws of electromagnetic induction and fluid dynamics. The MHD generator uses hot conductive ionized gas or plasma as the moving conductor whereas in the mechanical dynamo, in contrast, uses the motion of mechanical devices to accomplish this. Seeding materials such as potassium carbonate, potassium sulphates are used to enhance the conductivity of the ionized gas. The focus of the present study is to investigate alternative methods through which an MHD power generator can be coupled to the existing gas turbine and steam plants. In doing so, the thermal cycle efficiency of these conventional plants can be improved. A case study is also presented to calculate the power output and efficiency in a simple way.

The Development of A Reliability Evaluation Application for Power Plant Steam Turbine Vibrations to Predict Its Failure

A steam turbine is the most critical component in a thermal power plant. Due to its crucial function, it should be maintained to be able to operate without failure. This paper aims to develop an application that can be used to analyze the reliability and synchronization of vibrations in a single evaluation through the application. The application is helpful to decide the proper time the maintenance should be performed in order to provide a better maintenance strategy. In this paper, the application was used to make an ease in evaluating the reliability and vibration of a 670 MW power plant steam turbine. The reliability was analyzed by qualitative and quantitative methods. The vibration evaluation using Fast Fourier Transform (FFT) was done by diagnosing the failure symptoms from vibration spectrum. The analysis of synchronization of vibrations conducted by comparing the vibration frequency and the natural frequency of the system which can be calculated easily using the application. The algorithm program of both evaluations was built using GNU Octave software to make a friendly user interface. From the evaluation result, the most critical components of the steam turbine are coupling, labyrinth seals, bearing, diaphragm, turbine control valve, and turbine stop valve. The maintenance interval based on the expected reliability of 90% produces the highest reliability improvement. Based on the vibration analysis, there is no failure symptoms detected in the turbine bearings. Furthermore, the dominant frequencies of vibration are distant from the natural frequency. Therefore, the steam turbine condition is acceptable to operate.

PI control based on parameter space approach supported metaheuristic optimization algorithms and ANFIS in a natural gas combined cycle power plant

AbstractIn this article, proportional‐integral (PI) control to ensure stable operation of a steam turbine in a natural gas combined cycle power plant is investigated, since active power control is very important due to the constantly changing power flow differences between supply and demand in power systems. For this purpose, an approach combining stability and optimization in PI control of a steam turbine in a natural gas combined cycle power plant is proposed. First, the regions of the PI controller, which will stabilize this power plant system in closed loop, are obtained by parameter space approach method. In the next step of this article, it is aimed to find the best parameter values of the PI controller, which stabilizes the system in the parameter space, with artificial intelligence‐based control and metaheuristic optimization. Through parameter space approach, the proposed optimization algorithms limit the search space to a stable region. The controller parameters are examined with Particle Swarm Optimization based PI, artificial bee colony based PI, genetic algorithm based PI, gray wolf optimization based PI, equilibrium optimization based PI, atom search optimization based PI, coronavirus herd immunity optimization based PI, and adaptive neuro‐fuzzy inference system based PI (ANFIS‐PI) algorithms. The optimized PI controller parameters are applied to the system model, and the transient responses performances of the system output signals are compared. Comparison results of all these methods based on parameter space approach that guarantee stability for this power plant system are presented. According to the results, ANFIS‐ PI controller is better than other methods.

Structural and Parametric Optimization of S-CO2 Thermal Power Plants with a Pulverized Coal-Fired Boiler Operating in Russia

The Rankine cycle is widely used for electricity production. Significant weight and size characteristics of the power equipment working on superheated steam are the main disadvantages of such power plants. The transition to supercritical carbon dioxide (S-CO2) working fluid is a promising way to achieve a significant reduction in equipment metal consumption and to increase energy efficiency. This paper presents the results of thermodynamic analysis of S-CO2 thermal power plants (TPPs) utilizing the heat of combustion products of an energy boiler. It was found that the net efficiency of the developed S-CO2 TPP with a pulverized coal-fired boiler reached 49.2% at an initial temperature of 780 °C, which was 2% higher compared to the efficiency level of steam turbine power plants (STPPs) at a similar turbine inlet temperature.

Sensitivity analysis of low-pressure gland seal deformation behavior during vacuuming for a 1000 MW nuclear steam turbine based on thermo-mechanical coupling method

In startup process of steam turbine in nuclear power plant, undue deformation of gland seal (GS) may cause rubbing fault. Due to small gland seal clearance, modern advanced steam turbine requires precise control of gland seal deformation (GSD). In line with the above mentioned situations, firstly, a comparison study to reveal GSD behavior on low pressure (LP) casing of a 1000 MW nuclear steam turbine was carried out in startup process by using thermo-mechanical coupling method. The most serious condition for GSD was found out. Further, sensitivity analysis of GSD was conducted. The influence of back pressure and temperature of GS and bearing on GSD during vacuuming (VA) were researched. Finally, to evaluate the risk of rubbing fault, a formula for predicting the bottom clearance of GS during VA was proposed. The results indicate that, in startup process, the GS moves up significantly during VA. The calculated data are in good agreement with on-site measurements. The temperature rise of exhaust hood, which is influenced by GS temperature, makes the GS to lift up. The GS temperature is the most sensitive factor affecting GSD during VA. Rubbing fault may occur when the temperature of GS reaches 112 °C during VA. The results of this research has been used as a guidance for analyzing and improving operational reliability of steam turbine in nuclear power plants.

Coal-fired steam turbine power plant using oxygen-rich air as oxidizer

Mitigation of harmful and greenhouse gas emissions produced by the coal combustion in thermal power plant is a topic goal. Reduction of the nitrogen oxides, sulfur and ash emissions makes remarkable progress but the carbon dioxide emission still meets considerable difficulties mostly caused by the low greenhouse gas content in the flue gas. A prospective solution to this problem may be the fuel combustion in oxygen-enriched air, which increases the flue gas carbon dioxide content. In this technology, the carbon dioxide content in flue gas is higher and this results in its easier capture. This paper presents the thermodynamic analysis results of a steam turbine power production facility that burns coal in the air with high oxygen content. The computer simulation shows that the oxygen content increase from 21 to 95.6% increases the carbon dioxide content in flue gas by a factor of 3.3 and lowers the power consumption for carbon dioxide capture by 11%. On the other side, the power consumption for pure oxygen production reduces the facility’s net efficiency from 28.54 to 21.59%.

Hybrid-energy approach enabled by heat storage and oxy-combustion to generate electricity with near-zero or negative CO2 emissions

We assess a hybrid-energy approach that modifies a steam-turbine power plant to use renewable energy sources (electricity, plus options for geothermal and solar heat), plus fossil fuel (natural gas and coal) and/or waste biomass (e.g., Douglas fir woodchips). Heat storage allows heat to be created during periods of excess energy supply and for that heat to be converted to electricity when demanded. Excess electricity, such as from variable renewable energy (VRE), is used to generate oxygen for oxy-combustion furnaces that create very-hot, high-purity CO2 that heats granular rock beds in insulated vessels. Cool CO2 leaving the beds is dried, sent to compressors powered by excess VRE electricity, before being sent by pipeline to geologic CO2 storage. Very-hot CO2 transfers high-grade heat from storage to the power plant in a closed loop that returns medium-grade heat back to storage, allowing low- and medium-grade renewable-heat sources to be stacked beneath combustion heat, with all heat sources being converted to electricity at the same (high) thermal efficiency. Reliable, on-demand power may be generated with near-zero CO2 emissions with fossil fuel and with negative CO2 emissions with waste biomass. Our analyses show that with fossil fuel, up to 35% of gross power can be derived from renewable sources, while for waste biomass, it can be entirely derived from renewable sources. Because our approach has the potential to ensure that grids have a continuous supply of clean energy and because electricity is only generated once, when demanded, it could serve as an efficient alternative to bulk energy storage.

The influence of various optimization algorithms on nuclear power plant steam turbine exergy efficiency and destruction

This paper presents an exergy analysis of the whole turbine, turbine cylinders and cylinder parts in four different operating regimes. Analyzed turbine operates in nuclear power plant while three of four operating regimes are obtained by using optimization algorithms – SA (Simplex Algorithm), GA (Genetic Algorithm) and IGSA (Improved Genetic-Simplex Algorithm). IGSA operating regime gives the highest developed mechanical power of the whole turbine equal to 1022.48 MW, followed by GA (1020.06 MW) and SA (1017.16 MW), while in Original operating regime whole turbine develop mechanical power equal to 996.29 MW. In addition, IGSA causes the highest increase in developed mechanical power of almost all cylinders and cylinder parts in comparison to the Original operating regime. All observed optimization algorithms increases the exergy destruction of the whole turbine in comparison to Original operating regime - the lowest increase causes IGSA, followed by GA and finally SA. The highest exergy efficiency of the whole turbine, equal to 85.92% is obtained by IGSA, followed by GA (85.89%) and SA (85.82%), while the lowest exergy efficiency is obtained in Original operating regime (85.70%). Analyzed turbine, which operates by using wet steam is low influenced by the ambient temperature change. IGSA, which shows dominant performance in exergy analysis parameters of the analyzed turbine, in certain situations is overpowered by GA. Therefore, in optimization of steam turbine performance, IGSA and GA can be recommended.

Nuclear cogeneration for cleaner desalination and power generation – A feasibility study

Abstract Population growth, economic development, groundwater impairment due to salt water intrusion and local vulnerabilities caused by rising sea levels prompt immediate necessity for customized adaptation strategies for the cities of Homestead and Miami in Florida. This paper presents a feasibility study of nuclear energy driven cogeneration plant for water and power production in Homestead, FL. Miami-Dade and Homestead, Florida is home to the Turkey Point Nuclear Generating Facility. The focus of this study is to investigate the economic feasibility of a seawater desalination facility on the site of an existing nuclear generating plant. While the cost of seawater desalination is often too great to overcome, it is hypothesized that sharing the infrastructure and processes with a power generating facility will lower the cost of producing freshwater. The analysis was completed with the aid of the desalination modeling software, DEEP. First, we estimate the population growth and water demands for Homestead, FL and then identify a suitable water desalination plant configuration based on freshwater and power production costs. We then compare cogeneration (water and power) schemes based on different energy sources and desalination technologies. The energy sources considered are nuclear energy, oil and natural gas for steam turbine and combined cycle power plants. In addition, we evaluate the water and power production costs for hybrid desalination configurations. Finally, the freshwater costs through nuclear desalination were assessed with other options and conventional ground water system costs. Environmental emissions saved through nuclear desalination and the need for considering this option despite the high costs are discussed in detail. The study concluded that reverse osmosis desalination plant powered by nuclear energy produced water at the lowest cost which is still three times the cost of current water rates in Homestead, Florida.