scholarly journals Study of the soil temperature effect on the operation of a low-capacity power plant’s condenser

2020 ◽  
Vol 6 (1) ◽  
pp. 118-134
Author(s):  
Aleksandr E. Kishalov ◽  
Almir A. Zinnatullin
Keyword(s):  
Power Plant ◽  
Soil Temperature ◽  
Power Plants ◽  
Heat Removal ◽  
Energy Generation ◽  
Temperature Fields ◽  
Working Fluid ◽  
Stable Operation ◽  
Temperature State ◽  
Decentralized Energy

Every year, the share of decentralized energy generation in Russia is increasing. The following factors contribute to the development of this scenario: increased wear of the country’s energy system equipment, energy shortages, and lack of centralized energy supply in a number of regions and constantly rising tariffs. One of the methods of decentralized energy generation is the use of low-capacity power plants based on the Rankine cycle with an organic working fluid. The operation of such plants requires cooling and condensation of the working fluid by transferring its heat to the environment. This study discusses the design of such a power plant and the heat removal system to a cold source. is the authors consider the design of a condenser which is a horizontal pipeline placed in the ground. Seasonal fluctuations of the soil temperatures affect the operation of the condenser. Thereby, to ensure the stable operation of the power plant, it is necessary to quantitatively assess the effect of the annual dynamics of the soil temperature state on cooling and condensation of the coolant. The study of the temperature fields of the soil, pipeline and working fluid, as well as the lengths required for cooling and condensation of the working fluid, was carried out in the ANSYS CFX software package for numerical hydrodynamic modeling. A homogeneous flow model was chosen to simulate the momentum and condensation of a vapor-liquid medium. Also, the calculations were conducted in a one-dimensional formulation using an engineering method. A methodology for modeling complex processes of heat transfer to the soil using numerical modeling has been developed and verified. 12 calculations were made; the distributions of the steam dryness and temperature in the simulated region depending on the time of the year were obtained. The functions of the total length of the pipeline, cooling and condensation lengths on the soil temperature are analyzed. It has been established that the harmonic change in the temperature of the soil set as the initial condition determines a similar change in the lengths required for cooling and condensation of the working fluid. Using this technique, it is possible to calculate pipelines of more complex shapes. The obtained temperature distributions in cross sections allow to establish the optimal distance between the axes of the pipes when designing a condenser in the form of a bundle of horizontal pipes or a bent pipeline.

scholarly journals Seismic safety evaluation during site selection for the nuclear power plants in Bangladesh

2018 ◽  
Vol 4 (4) ◽  
pp. 251-256 ◽  
Author(s):  
Sergey Shcheklein ◽  
Ismail Hossain ◽  
Mohammad Akbar ◽  
Vladimir Velkin
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Spent Nuclear Fuel ◽  
Heat Removal ◽  
Good Time ◽  
Diagnostics System ◽  
Seismic Impacts

Bangladesh lies in a tectonically active zone. Earlier geological studies show that Bangladesh and its adjoining areas are exposed to a threat of severe earthquakes. Earthquakes may have disastrous consequences for a densely populated country. This dictates the need for a detailed analysis of the situation prior to the construction of nuclear power plant as required by the IAEA standards. This study reveals the correlation between seismic acceleration and potential damage. Procedures are presented for investigating the seismic hazard within the future NPP construction area. It has been shown that the obtained values of the earthquake’s peak ground acceleration are at the level below the design basis earthquake (DBE) level and will not lead to nuclear power plant malfunctions. For the most severe among the recorded and closely located earthquake centers (Madhupur) the intensity of seismic impacts on the nuclear power plant site does not exceed eight points on the MSK-64 scale. The existing predictions as to the possibility of a super-earthquake with magnitude in excess of nine points on the Richter scale to take place on the territory of the country indicate the necessity to develop an additional efficient seismic diagnostics system and to switch nuclear power plants in good time to passive heat removal mode as stipulated by the WWER 3+ design. A conclusion is made that accounting for the predicted seismic impacts in excess of the historically recorded levels should be achieved by the establishment of an additional efficient seismic diagnostics system and by timely switching the nuclear power plants to passive heat removal mode with reliable isolation of the reactor core and spent nuclear fuel pools.

Influence of a Variable in Time Heat Transfer Coefficient on Stresses in Model of Power Plant Components

2013 ◽  
Author(s):  
Jerzy Okrajni ◽  
Mariusz Twardawa
Keyword(s):  
Heat Transfer ◽  
Power Plant ◽  
Mechanical Behaviour ◽  
Power Plants ◽  
Thermal Loading ◽  
Computer Modelling ◽  
Temperature Fields ◽  
Fluid Medium ◽  
Stress Changes ◽  
Plant Components

The paper discusses the issue of modelling of strains and stresses resulting from heating and cooling processes of components in power plants. The main purpose of the work is to determine the mechanical behaviour of power plant components operating under mechanical and thermal loading. Finite element method (FEM) has been used to evaluate the temperature and stresses changes in components as a function of time. Temperature fields in the components of power plants are dependent, among parameters, on variable heat-transfer conditions between components and the fluid medium, which may change its condition, flowing inside them. For this reason, evaluation of the temperature field and the consequent stress fields requires the use of heat-transfer coefficients as time-dependent variables and techniques for determining appropriate values for these coefficients should be used. The methodology of combining computer modelling of the temperature fields with its measurements performed at selected points of the pipelines may be used in this case. The graphs of stress changes as a function of time have been determined for the chosen plant components. The influence of the heat transfer conditions on the temperature fields and mechanical behaviour of components have been discussed.

Cycle Calculations of a Small-Scale Heat Removal System With Supercritical CO2 As Working Fluid

2017 ◽  
Author(s):  
Marcel Strätz ◽  
Jörg Starflinger ◽  
Rainer Mertz ◽  
Michael Seewald ◽  
Sebastian Schuster ◽  
...  
Keyword(s):  
Power Plant ◽  
Supercritical Co2 ◽  
Heat Removal ◽  
Working Fluid ◽  
Small Scale ◽  
Brayton Cycle ◽  
Additional Heat ◽  
Decay Heat ◽  
Heat Removal System ◽  
Removal System

In case of an accident in a nuclear power plant with combined initiating events, (loss of ultimate heat sink and station blackout) additional heat removal system could transfer the decay heat from the core to and diverse ultimate heat sink. On additional heat removal system, which is based upon a Brayton cycle with supercritical CO2 as working fluid, is currently investigated within an EU-funded project, sCO2-HeRo (Supercritical carbon dioxide heat removal system). It shall serve as a self-launching, self-propelling and self-sustaining decay heat removal system to be used in severe accident scenarios. Since a Brayton cycle produces more electric power that it consumes, the excess electric power can be used inside the power plant, e.g. recharging batteries. A small-scale demonstrator will be attached to the PWR glass model at Gesellschaft für Simulatorforschung GfS, Essen, Germany. In order to design and build this small-scale model, cycle calculations are performed to determine the design parameters from which a layout can be derived.

scholarly journals THERMOACOUSTIC ENGINE AS A LOW-POWER COGENERATION ENERGY SOURCE FOR AUTONOMOUS CONSUMER POWER SUPPLY

2021 ◽  
Vol 18 (2) ◽  
pp. 60-66
Author(s):  
A.D. Mekhtiyev ◽  
Keyword(s):  
Power Plant ◽  
Low Power ◽  
Power Supply ◽  
Thermal Power Plant ◽  
Power Plants ◽  
Thermal Power ◽  
Saturated Steam ◽  
Working Fluid ◽  
Thermoacoustic Engine ◽  
Basic Principles

The article deals with the issue of using a thermoacoustic engine as a low-power cogeneration source of energy for autonomous consumer power supply capable of operating on various types of fuel and wastes subject to combustion. The analysis of the world achievements in this field of energy has been carried out. A number of advantages make it very promising for developing energy sources capable of complex production of electrical and thermal energy with a greater efficiency than that of present day thermal power plants. The proposed scheme of a thermal power plant is based on the principle of a Stirling engine, but it uses the most efficient and promising thermoacoustic converter of heat into mechanical vibrations, which are then converted into electric current. The article contains a mathematical apparatus that explains the basic principles of the developed thermoacoustic engine. To determine the main parameters of the thermoacoustic engine, the methods of computer modeling in the DeltaEC environment have been used. A layout diagram of the laboratory sample of a thermal power plant has been proposed and the description of its design has been given. It has been proposed to use dry saturated steam as the working fluid, which makes it possible to increase the generated power of the thermoacoustic engine.

scholarly journals Performance Modeling of the Weather Impact on a Utility-Scale PV Power Plant in a Tropical Region

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Ajith Gopi ◽  
K. Sudhakar ◽  
Ngui Wai Keng ◽  
Ananthu R. Krishnan ◽  
S. Shanmuga Priya
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Research Work ◽  
Energy Generation ◽  
Plant Performance ◽  
Tropical Region ◽  
Weather Impact ◽  
Weather Parameters ◽  
Utility Scale ◽  
Solar Generation

Solar photovoltaics and the associated applications are now considered the most promising technologies for a sustainable future. The performance of the PV power plants is not studied in detail with respect to the influence of various weather parameters like rain, relative humidity, and atmospheric pressure on energy generation. The objective of this research work is to analyze and model the weather impact of a utility-scale PV power plant in a tropical region. The methodology involves the detailed analysis of the PV plant performance for various weather seasons and modeling the energy generation based on important weather parameters obtained from a Solar Radiation Resource Assessment (SRRA) station installed at the PV power plant location itself. Solar generation and its performance are affected during the rainy seasons, and it turns out to be a typical phenomenon in the humid tropical region. A regression model of solar generation for all the weather seasons is generated based on different weather parameters.

scholarly journals ANALISIS KEGAGALAN OPERASI COOLING TOWER FAN UNIT 2B PLTU ASAM ASAM

JTAM ROTARY ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 65
Author(s):  
Andhika Bayu Oktavianto ◽  
Mastiadi Tamjidillah
Keyword(s):  
Power Plant ◽  
Preventive Maintenance ◽  
Power Plants ◽  
Cooling Tower ◽  
Cooling Water ◽  
Working Fluid ◽  
Steam Power ◽  
Steam Power Plant ◽  
Plant Uses ◽  
Engineering Team

Salah satu pembangkit listrik di Indonesia adalah pembangkit listrik Asam Asam yang terletak di dekat mulut tambang batubara. Setiap pembangkit listrik membutuhkan sejumlah besar air sebagai fluida kerja atau sebagai air pendingin. Pembangkit Listrik Tenaga Uap Asam Asam Batubara menggunakan air sungai sebagai air pendingin dengan mesin pendingin sebagai mesinnya. Pada bulan September 2017, menara pendingin unit 2B dari PLTU Asam Asam Batubara mengalami kegagalan operasi karena spacer rusak dan membuat PLTU Asam Asam Batubara mengalami penurunan dan kerugian lainnya. Tim teknik mendiagnosis kasus tersebut karena ketidakselarasan. Berdasarkan uraian akar penyebab masalah, ada tiga masalah utama yang mungkin terjadi yaitu: misalignment, unbalance, dan rotasi gearbox berat. Misalignment adalah pemicu utama untuk serangkaian masalah yang menyebabkan kegagalan operasi menara pendingin. Maka perlu mempelajari masalah utama yang menyebabkan kegagalan operasi menara pendingin untuk ditindaklanjuti dengan pemeliharaan preventif sesuai dengan kondisi saat ini untuk mencegah kegagalan yang serupa di unit 2B dan unit serupa lainnya. One of the power plants in Indonesia is the Asam Asam power plant located near the mouth of the coal mine. Each power plant requires large amounts of water as a working fluid or as a cooling water. Asam Asam Coal Fired Steam Power Plant uses river water as a cooling water with the cooling towers as its engine. In September 2017, the cooling tower unit 2B of Asam Asam Coal Fired Steam Power Plant experienced an operation failure because of the spacer was broken and made the Asam Asam Coal Fired Steam Power Plant to experience derating and other losses. The engineering team diagnoses the case due to misalignment. Based on the description of the root causes of the problem, there are three main problems that might occur namely : misalignment, unbalance, and heavy gearbox rotation. Misalignment is the main trigger for a series of problems causing failure of cooling tower operations. Then it is necessary to study the main problems causing the failure of the cooling tower operation to be followed up with preventive maintenance in accordance with the current conditions to prevent similar failures in unit 2B and other similar units.

scholarly journals The use of organic zeotropic mixture with high temperature glide as a working fluid in medium-temperature vapor power plant

2017 ◽  
Vol 21 (2) ◽  
pp. 1153-1160 ◽  
Author(s):  
Aleksandra Borsukiewicz
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Electrical Energy ◽  
Hot Water ◽  
Working Fluid ◽  
Large Temperature ◽  
Medium Temperature ◽  
Calculation Results ◽  
Zeotropic Mixture ◽  
Selection Of

The paper presents the idea of using organic substances as working fluids in vapor power plants, in order to convert the low and medium temperature thermal energy sources into electrical energy. The calculation results of the power plant efficiency for butane-ethane zeotropic mixtures of different mass compositions, for the power plant supplied with hot water having a temperature of 120?C. Based on the results of thermal-flow calculations it was found that the use of zeotropic mixture does not allow to increase the efficiency and output of the power plant (these values appeared as slightly lower ones). However, it was found that, through the selection of a mixture of sufficiently large temperature glide, the heat exchange surface of the condenser can be reduced or a co-generation system can be implemented.

scholarly journals Performance Analyses and Evaluation of Co2 and N2 as Coolants in a Recuperated Brayton Gas Turbine Cycle for a Generation IV Nuclear Reactor Power Plant

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Emmanuel O. Osigwe ◽  
Arnold Gad-Briggs ◽  
Theoklis Nikolaidis ◽  
Pericles Pilidis ◽  
Suresh Sampath
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Reactor ◽  
Reactor Power ◽  
Critical Conditions ◽  
Working Fluid ◽  
Closed Cycle ◽  
Gas Turbine Cycle

Abstract As demands for clean and sustainable energy renew interests in nuclear power to meet future energy demands, generation IV nuclear reactors are seen as having the potential to provide the improvements required for nuclear power generation. However, for their benefits to be fully realized, it is important to explore the performance of the reactors when coupled to different configurations of closed-cycle gas turbine power conversion systems. The configurations provide variation in performance due to different working fluids over a range of operating pressures and temperatures. The objective of this paper is to undertake analyses at the design and off-design conditions in combination with a recuperated closed-cycle gas turbine and comparing the influence of carbon dioxide and nitrogen as the working fluid in the cycle. The analysis is demonstrated using an in-house tool, which was developed by the authors. The results show that the choice of working fluid controls the range of cycle operating pressures, temperatures, and overall performance of the power plant due to the thermodynamic and heat properties of the fluids. The performance results favored the nitrogen working fluid over CO2 due to the behavior CO2 below its critical conditions. The analyses intend to aid the development of cycles for generation IV nuclear power plants (NPPs) specifically gas-cooled fast reactors (GFRs) and very high-temperature reactors (VHTRs).

Specified Maintenance of Steam Turbines in Geothermal Power Plants

2013 ◽  
Author(s):  
Almar Gunnarsson ◽  
Ari Elisson ◽  
Magnus Jonsson ◽  
Runar Unnthorsson
Keyword(s):  
Power Plant ◽  
Condition Monitoring ◽  
Power Plants ◽  
Maintenance Management ◽  
Working Fluid ◽  
Steam Turbines ◽  
Effect Analysis ◽  
Geothermal Power Plant ◽  
Management Procedures ◽  
Geothermal Power

In a geothermal power plant the working fluid used to produce electricity is often wet steam composed of corrosives chemicals. In this situation, more frequent maintenance of the equipment is required. By constructing an overview for maintenance in geothermal power plants and how it can be done with minimum power outages and cost, the geothermal energy can be made more competitive in comparison to other energy resources. This work is constructed as a part of a project, which has the aim of mapping the maintenance management system at the Hellisheiði geothermal power plant in Iceland. The object of the project is to establish Reliability Centered Maintenance (RCM) program for Hellisheiði power plant that can be utilized to establish efficient maintenance management procedures. The focus of this paper is to examine the steam turbines, which have been defined as one of the main subsystems of the power plant at Hellisheiði. A close look will be taken at the maintenance needed for the steam turbines by studying for example which parts break down and how frequently they fail. The local ability of the staff to repair or construct turbine parts on-site is explored. The paper explores how the maintenance and condition monitoring is carried out today and what can be improved in order to reduce cost. The data collected is analyzed using Failure Mode and Effect Analysis (FMEA) in order to get an overview of the system and to help organizing maintenance and condition monitoring of the power plant in the future. Furthermore, the paper presents an overview of currently employed maintenance methods at Hellisheiði power plant, the domestic ability for maintaining and repairing steam turbines and the power plant’s need for repairs. The results show that the need for maintenance of the geothermal steam turbines at Hellisheiði power plant is high and that on-site maintenance and repairs can decrease the cost.

Organic Rankine Cycle as Bottoming Cycle to a Combined Brayton and Clausius - Rankine Cycle

2013 ◽  
Vol 597 ◽  
pp. 87-98
Author(s):  
Dariusz Mikielewicz ◽  
Jan Wajs ◽  
Elżbieta Żmuda
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Large Scale ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Working Fluid ◽  
Preliminary Evaluation ◽  
Organic Fluids ◽  
Steam Cycle

A preliminary evaluation has been made of a possibility of bottoming of a conventional Brayton cycle cooperating with the CHP power plant with the organic Rankine cycle installation. Such solution contributes to the possibility of annual operation of that power plant, except of operation only in periods when there is a demand for the heat. Additional benefit would be the fact that an optimized backpressure steam cycle has the advantage of a smaller pressure ratio and therefore a less complex turbine design with smaller final diameter. In addition, a lower superheating temperature is required compared to a condensing steam cycle with the same evaporation pressure. Bottoming ORCs have previously been considered by Chacartegui et al. for combined cycle power plants [ Their main conclusion was that challenges are for the development of this technology in medium and large scale power generation are the development of reliable axial vapour turbines for organic fluids. Another study was made by Angelino et al. to improve the performance of steam power stations [. This paper presents an enhanced approach, as it will be considered here that the ORC installation could be extra-heated with the bleed steam, a concept presented by the authors in [. In such way the efficiency of the bottoming cycle can be increased and an amount of electricity generated increases. A thermodynamic analysis and a comparative study of the cycle efficiency for a simplified steam cycle cooperating with ORC cycle will be presented. The most commonly used organic fluids will be considered, namely R245fa, R134a, toluene, and 2 silicone oils (MM and MDM). Working fluid selection and its application area is being discussed based on fluid properties. The thermal efficiency is mainly determined by the temperature level of the heat source and the condenser conditions. The influence of several process parameters such as turbine inlet and condenser temperature, turbine isentropic efficiency, vapour quality and pressure, use of a regenerator (ORC) will be presented. Finally, some general and economic considerations related to the choice between a steam cycle and ORC are discussed.

Sign in / Sign up

Export Citation Format

Share Document