Power Plant Unit Research Articles

Investigation into the Evolution of Unsteady Flow of Lubricating Oil System in Guide Bearing of a Pump Turbine Unit

The water-guide bearing lubricating oil system of pumped storage unit is prone to oil dumping and oil spillage during the start-up of the unit, which seriously threatens the safe and stable operation of the unit. In this study, a three-dimensional unsteady numerical simulation is performed to investigate the causes of oil dumping and oil spillage of a water-guide bearing lubricating oil system of a pumped storage power plant unit based on the VOF (volume of fluid) multiphase flow model and Realizable k-ε model. The unsteady flow characteristics inside the rotating oil basin and pump-type Pitot tube during the start-up process are analyzed. The results demonstrate that the change of the external characteristics of the lubricating oil system can be divided into two stages, the initial formation process of the lubricating oil flow and the stable circulation process of the lubricating oil flow. In the initial formation process, the pressure inside the rotating basin is uniformly distributed in the circumferential direction, and a high-pressure zone is generated near the inlet of the pump-type Pitot tube, driving the lubricant flow to the stationary basin above; in the stable flow cycle process, the internal lubricant flow velocity gradually decreases along the radius direction, and a large vortex zone appears behind the pump-type Pitot tube and at the inlet of it. This phenomenon leads to the lubricating oil pressure here to be lower than the saturation vaporization pressure, which may trigger lubricating oil atomization and then overflow from the seal ring. This study is committed to provide theoretical analysis and engineering reference for the investigation of the causes of oil dumping and oil spillage in the lube oil system of water guide bearings of pumped storage units.

A Novel Integrated Design for Heat and Water Recovery from Exhaust Flue Gas of Bandar Abbas Power Plant

This study concerns a theoretical design of a condensing heat exchanger for a 320 MW unit of Bandar Abbas thermal power plant in the south of Iran. A film theory in conjunction with heat and mass transfer analogy is used as the theoretical basis of the design. The condensing unit is used for heat and mass recovery from the natural gas-fired boiler flue gases. The assumed condensing unit includes 4 equal capacity condensing heat exchangers, each of which is supposed to reduce the flue gas temperature from 160 ℃ to 53℃. Decreasing the flue gas temperature to below the dew point temperature of its water vapor causes condensation (latent) and sensible heat transfer. The analysis was done for 13%, 15%, and 17% of the water vapor volume fraction in the flue gases, and based on the 17% water vapor fraction, 52.8 tons/hr of water was recovered. This recovered water could be used as the cooling tower makeup, and accordingly, almost 14% of water consumption is saved. The recovered heat by the condensing unit is also being used as the heat source of an ORC cycle, and up to 2.8 MW power is estimated to be generated depending on the evaporation temperature.

Health Index Estimation of Wind Power Plant Using Neurofuzzy Modeling.

According to the Tamil Nadu Energy Development Agency (TEDA) in the 2019-20 academic year, the wind power plant produces 23% of the biomass power supply in the Indian electrical commodities. To maintain the power withstanding capability needed for future electrical commodities, a yearly power shutdown program is implemented. An additional wind power plant unit will be erected and create more electricity, thereby balancing India's commercial electricity needs. Even in a nonstationary working environment, continuous monitoring and analyzing the efficiency of wind turbines is a more difficult task. Consequently, in this paper, a health index calculation for wind power plants is proposed utilizing neurofuzzy (NF) modeling. Wind generator efficiency can be measured mathematically by recording three crucial primitivistic such as observed rotation speed, generation wound temperature, and gearbox heat. Fuzzy rules are used to design the parameters of the neural network (NN), and the accumulated signal is compared using the nonlinear extrapolation approach to determine the wind generator's behavior and evaluate the hazards. During the experimental study, two windows of 24 hours and 60 hours are used, where the deviation signal required for the hazard induction is investigated. The proposed approach can accurately calculate the wind generator's health state. As a result of an improved health operating and management (HOM) system, the amount of power generated by industrials and domestic appliances has increased dramatically.

Derivation of a new dose constraint applicable to radioactive discharges from Korean nuclear power plants through retrospective dose assessment

A new methodology to derive a dose constraint for radioactive effluent from a unit of nuclear power plant (NPP) through retrospective assessment was developed to reflect operational flexibility in line with international standards. The new dose constraint can retain the safety margin between the offsite dose and the past dose constraints. As case studies, the new approach was applied to 24 Korean NPPs to address the limitations of the existing seven dose constraints that do not fully comply with current international radiation protection standards. Therefore, an effective dose constraint for Korean NPPs was proposed as no less than 0.15 mSv/y, which is comparable to the international practices and previous studies (0.05–0.3 mSv/y). Although the lower bound of the equivalent dose constraint was calculated as 0.17 mSv/y, it is not proposed in this study since the compliance with the derived effective dose constraint can prevent accompanied equivalent doses to any organs from exceeding equivalent dose limits. The new framework and the case studies are expected to contribute toward and support the revision of existing dose constraints for radioactive effluent from NPPs, ensuring better compliance with the current international safety standards as well as reflect the operational flexibility in practice.

Influence of frequency and power control modes on the technical condition of hydraulic units of hydroelectric power plants

The features of the operation of hydroelectric power plants, which are used to regulate the frequency and power in the power system with a wide range of load variations and with varying degrees of intensity of operation mode variations, are considered. An approach is proposed to assess the impact on the reliability of hydraulic turbine equipment used in these modes. When examining the equipment of existing hydroelectric power plants, it has been revealed that the mode of automatic secondary regulation of frequency and power flows in the power system has the greatest impact on the technical condition of hydraulic turbines. Intense participation in regulation leads to an increase in dynamic loads on the hydraulic unit, loads on the friction pairs of the regulating elements of the turbine compared to the basic, semipeak and peak modes and leads to additional wear, reduced reliability and deterioration of the technical condition of the equipment. The operation in the automatic secondary regulation mode of hydraulic units at different HPPs differs depending on the function performed in the power system. To determine the loading of a hydraulic unit with transient load variation modes during operation in the mode of automatic secondary regulation of frequency and power flows, it is proposed to introduce a parameter characterizing the intensity of operation of hydraulic units of HPP in the aforesaid mode and to take it into account in order to accumulate data on the actual operating modes of hydraulic units and use it in assessing and predicting the technical condition of equipment.

PERBAIKAN DAN PEMELIHARAAN MOTOR LISTRIK PENGGERAK WATER JET PUMP DI AREA WASTE HEAT RECOVERY SYSTEM PT CEMINDO GEMILANG

Electricity is one of the vital needs that is indispensable for all humans and other places, one of which is PT. Cemindo Gemilang, engaged in the cement-producing industry, requires a huge electricity capacity. To reduce or reduce the cost of electrical energy, a power plant unit and a WHRS (waste heats recovery system) were made to supply electrical energy to the cement plant area. PT. Cemindo Gemilang and the Power Plant rely heavily on electric motors, almost all of which operate using electric motors. The electric motor is a single-phase or three-phase type with a voltage of 11 KV, 6.6 KV or 400 volts. When all generating units operate, all electric motors that play an essential role will continue to be active so that damage is often caused by operation and service life therefore in the power plant department, and there is an electrical and mechanical maintenance division to maintain the continuity of the power plant operational system. This study's aim 1). Explain about electric motors, 2). Explain the definition of the water jet pump, 3). Explain how the water jet pump works 4). Explain the components used in electric motors and their repair and maintenance.

Optimizing the Potential of Solar Energy PT PJB UP Muara Karang Rooftop Area Using HelioScope

Year after year, there has been a rise in use of electrical power. The industrial, home, commercial, and public sectors accounted for 234,617.88 GWh of PLN's electrical energy sales in 2018. Meanwhile, the household, industrial, commercial, social sector, government office buildings, and public street lighting consumed 2,857.06 GWh of electrical energy in DKI Jakarta. The majority of the energy resources required by interconnected networks are fossil (coal). As a result, a future alternative to fossil fuels is required. Optimizing solar energy that may be employed in urban settings is one of the uses of renewable energy. The building sector consumes up to 40% of the total annual energy. By installing a renewable energy system on the roof of PT PJB Muara Karang power plant unit. The solar power plant energy potential on the roof of PT PJB UP Muara Karang administration building was simulated with HelioScope and using Quantitative Descriptive Method to maximize the rooftop area by installing 143 solar panel modules. which is capable of supplying 75.11 percent of the energy needs at PT. PJB UP Muara Karang.

Expert express assessment of the impact of heat and mass transfer processes on the residual life of the WWER-1000 reactor vessel due to metal embrittlement

The WWER-1000 reactor is operated at 13 of the 15 operating power units of Ukraine's nuclear power plants (NPPs). Ensuring long-term and safe operation of such reactors is the basis for reliable operation of all 13 Ukrainian nuclear power plants units and the guarantor of Ukraine's energy security. The determining and leading factor influencing the safety and proper residual life of the WWER-1000 reactor vessel is the radiation embrittlement of the reactor steel. The consequences of radiation embrittlement of reactor steel are negatively manifested in emergencies with cooling of the core. This process itself – radiation embrittlement – accumulates constantly and gradually. Therefore, it is important to monitor it by periodically performing ongoing rapid assessments of the brittle strength of the WWER-1000 reactor vessel (along with other factors, including cyclic damage, as discussed in a previous publication). Therefore, it is important to use the calculated express methods of periodic assessment of the brittle strength of the WWER-1000 reactor vessel with guaranteed accuracy. The effectiveness of the approach is supported by low cost of resources – engineering staff, fast and relatively simplified use of computers and software. As an example and confirmation of the applicability of the proposed approach, an expert rapid assessment of the fragile strength and residual life of the reactor vessel of Unit № 1 of the South-Ukrainian Nuclear Power Plant was performed. This takes into account the actual, passport characteristics of its metal. The negative impact of the rigid regime with cooling of the WWER-1000 reactor of Unit № 1, not taken into account by the operating organization (South-Ukrainian Nuclear Power Plant) when extending its designated resource / service life, is shown. timely to clarify complex factors, technical aspects and parameters, as well as – their possible negative effects on the safe operation of systems and elements of nuclear power plants.

EFFECT OF FLY ASH ON GROWTH OF VIGNA MUNGO L.

Parichha thermal power plant is a unit of national thermal power plant situated in Jhansi district of Uttar Pradesh India, which uses bituminous coal for electricity generation. After combustion in boilers this coal comes out from the chimneys and get mixed with air then precipitated in the surrounding area in the form of fly ash which is bring together by electronic precipitators. Present work has been taken to work out the effect of different concentrations of fly ash on the growth and yield of Vigna mungo L. variety T-9 obtained from certified seed centre. Seeds of Vigna mungo L. have been examined under different concentrations of fly ash amended soil. Different plant parameters such as percent of germination, plant height in terms of shoot and root length, fresh weight, dry weight and chlorophyll content have been analyzed along with crop yield. Maximum germination percent i.e. 94% have been recorded from the sample mixed with 25% fly ash and 75% field soil. For other vegetative parameters it has been found that sample 25% fly ash and 75% soil is highly supportive for plant growth. This has been supported by the leaf samples analyzed for chlorophyll content in the fresh leaves, where maximum amount of chlorophyll content has been recorded.

The Design of Thermodynamic System Instrument & Control for the Daya Bay Turbine High Pressure Cylinder Retrofit

Before the retrofit, the equipments of the turbine high pressure cylinder of the Daya Bay Nuclear Power Plant is of the old technology. The design of the leaf shape and the steam runner is not advanced, and the equipments are aged after more than 20 years’ operation. From the point of increasing the power and improving the reliability of the equipments, it’s decided to retrofit the turbine high pressure cylinder of Daya Bay Nuclear Power Plant unit 1 and unit 2. The retrofit relates to the design and modification of many secondary loop thermodynamic systems’ instrument & control parameters, in order to match with the first loop reactor control systems, and also the mechanism and electric systems, it’s necessary to verify and optimize these designed parameters of the units after the retrofit. This design and analysis method and experience of the secondary loop thermodynamic systems’ instrument & control parameters can be referred by the similar retrofit of other nuclear power plants.

Identification of Potential Geothermal Energy Used for Vaccine COVID-19 Cold Storage Box Using Absorptive Refrigeration

A variety of vaccines of Covid 19 have been developed by different drug makers. Each vaccine brand requires different storage temperature ranged from 2-8°C, which then requires a cold storage box. In Indonesia, vaccine transportation and storage become big challenges to ensure the vaccines in good condition before use. This research focused to find out the possibility of using geothermal energy from Lahendong geothermal power plant unit 5 in Tompaso, North Sulawesi, for 5 liters-cold storage for Covid-19 vaccine using ammonia-water absorptive refrigeration and to identify the possible temperatures for storage of vaccine. Based on the absorption refrigeration system calculation, the current study found that the average evaporator temperature is 3°C, with cooling load of 1.03 kW and COP of 0.43. This cooling load requires a brine of 59.98 kg/s from the Lahendong geothermal power plant.

Techno-environmental assessment of gas-based power plant and renewable unit in the presence of power to gas system and gas storages for emission reduction using information gap decision theory

Carbon dioxide is the most common greenhouse gas and a major contributor to global warming. Utilization of power to gas systems (P2G) in conventional power plants to reduce the CO2 emissions is one of the promising approaches. In this paper, a P2G system combined from electrolysis and methanation units is proposed for recycling CO2 emission. This P2G system is considered to operate environmentally and economically integrated with a gas-based power plant (GBPP) and renewable energy resources like wind generation unit. In addition, wind generation uncertainty parameter is modeled through three various strategies as robustness, opportunity, and basic functions by using the information gap decision theory (IGDT) optimization method considering the wind generation uncertainty parameter, which has a major impact on the optimal operation of the proposed GBPP-P2G system. Furthermore, CH4 and CO2 gas storage units are utilized in the P2G system to enhance the reduction of CO2 emission. Results reveal the effectiveness of the proposed GBPP-P2G system in sharply decreasing the CO2 emission and wind curtailment.

ECOLOGICAL AND POWER INDICATORS OF CONTROL TECHNOLOGIES OF THE INTEGRATED POWER SYSTEM OF UKRAINE WITH THE USE OF ELECTRIC HEAT GENERATORS

The article presents the results of determining the power and ecological indicators of the implementation of innovative control technology of the Integrated Power System (IPS) of Ukraine using electric heat generators (EHG). This control technology is based on the use of modern principles of interaction of power-generating and heat-generating systems, which will take place during the performance of Daily curve of electricity load (DCEL) compaction processes controlled by the load of EHG complexes. The implementation of this control technology involves the introduction in the IPS from 1 GW to 2 GW of electric power EHG systems. A simplified method of calculating the amount of electricity to ensure the operation of EHG complexes during the year. During the compaction of DGEN in the hours of night falling during the year will be generated an additional 3,629 billion kWh of electricity. If this energy is generated by the existing coal-fired thermal power plants, an additional 1659.2 thousand tpp/year will be consumed. The thermal energy that will be produced at the EHG will reduce the consumption of natural gas for heating and the hot water by gas boilers of district heating systems. The operation of EHG complexes will save 353.5 million m3 of natural gas. The results of calculations of ecological and power indicators in the implementation of EHG for the control of IPS are presented for two successive stages. At the first stage, an increase in the minimum level of DCEL by 1 GW is considered. This will allow to move away from the daily practice of stopping 7-10 power units of coal-fired power plants. In the second stage, an increase in the minimum level of DCEL by another 1 GW is considered. This will allow to change about 25 maneuverable power units of TPPs with a capacity of 200 and 300 MW each to the basic mode of operation during the night falling of DCEL. With the use of this control technology it will be possible to form in the IPS self-sufficient reserves of shunting capacity for secondary and tertiary power regulation in the power system. Increasing the share of thermal power plants that will operate in the basic mode of electricity generation allows us to consider the possibility of replacing thermal generation with nuclear power plants in the future. Bibl. 16, Fig. 3, Tab. 4.

Simplified Assessment Methodology of Radionuclide Contamination for Subsurface Soil

Determining whether to release a site after decommissioning a nuclear facility should be preceded by an environmental impact assessment of the exposure radiation dose according to the radionuclides in the soil. Currently, in Korea, various evaluation methodologies and decommissioning technologies are being studied for the first decommissioning of nuclear power plants, starting with Kori Nuclear Power Plant Unit (Kori-1), which is based on the “Multi-Agency Radiation Survey and Site Investigation Manual MARSSIM” developed in the United States. The scope and evaluation targets of deep soil may differ depending on the purpose, but it has been confirmed that the International Atomic Energy Agency and the U.S. Nuclear Regulatory Commission are targeting subsurface soil. MARSSIM outlines the need for an evaluation of this subsurface soil but does not suggest specific methods. In NUREG-1757, which complements MARSSIM, it is confirmed that subsurface soil specifically means a soil layer that is 15 to 30 cm deep in the surface layer. In the current study, using the previously verified computational code RESidual RADioactivity (RESRAD)-ONSITE, a methodology for summation is proposed to evaluate the impact of subsurface soil more flexibly and realistically while minimizing the exposure dose evaluation procedure. When using RESRAD-ONSITE according to this evaluation methodology, it was confirmed that it is possible to respond to changes in the depths of various soil layers. In addition, it was also confirmed that this methodology is adaptable to the contamination of nuclides, such as 60Co, 137Cs, 152Eu, and 154Eu, which are expected to be major nuclides when decommissioning nuclear facilities.

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.

Critical speed calculation of a refurbishment of 11MW hydro power plant unit

Hydro generator design is a significant issue in terms of safety, efficiency, and energy production sustainability. One of the most crucial issues about design criteria is to satisfy the needs of the project?s critical speed. In this work, the critical speed calculation of an 11 MW hydro power plant was investigated with several design steps. Numerical solution methodologies were implemented using ARMD?. A generator design was developed, and the implementation of the rotor was carried out in Antalya, Turkey. Vibration and displacements of the hydro generator are adequate. The generator unit is active for 3 years and have never encountered runaway speeds. No critical speed or resonance speed is anticipated for the designed hydro generator unit.

Mitigating CO2 emission in pulverized coal-fired power plant via co-firing ammonia: A simulation study of flue gas streams and exergy efficiency

Coal-fired power plants are one of the major sources of CO2 emission, and the novel application of directly co-firing the carbon-free fuel ammonia into the coal-fired power plants is emerging as a promising method of CO2 emission reduction. In this study, simulations of the boiler system of a 600 MWe coal-fired power plant unit were performed in both coal-fired condition and ammonia-coal co-firing conditions, and the impacts of ammonia co-firing on the emission and thermal properties of flue gas, exergy loss, and exergy efficiency were analyzed. Two co-firing scenarios (identical adiabatic flame temperature scenario and identical excess air coefficient scenario) were compared, both assuming that the total heating value of the fuel into the furnace kept unchanged with different ammonia co-firing ratios (5%, 10%, 15%, 20% on heating value basis). The results showed that CO2 emission was effectively reduced by 24.08 t/h for every 5% increase in the ammonia co-firing ratio. The amount of total flue gas was also reduced while both the content and the emission rate of H2O were increased with ammonia co-firing. Consequently, the specific heat capacity of flue gas increased and further changed its temperature distribution profile. Compared with the coal-fired base case, the exergy loss in the furnace under the ammonia co-firing conditions increased continuously as the ammonia co-firing ratio increased, suggesting that the irreversible loss of the ammonia combustion process was greater than that of coal. By contrast, the exergy loss of heat exchangers and fans decreased in ammonia co-firing conditions. Finally, the exergy efficiency of the boiler system was only slightly reduced (53.82% vs. 53.27%–53.22%) in ammonia co-firing conditions, showing that co-firing ammonia in coal-fired power plant would not significantly deteriorate the thermal economy.

Development and Research of Composite Coatings of Ti-B System, Sprayed by Microplasma Method

The paper presents the results of development and study of a composite powder of Ti-TiB2 system. Comprehensive studies of composite coatings formed by microplasma spraying of the developed powders are carried out. It is determined that the developed composite materials are promising for use in elements and friction units of wind power plants and shipbuilding engineering objects.

An intelligent optimization method of reload core loading pattern and its application

Reload core loading pattern design is the key content related to safety, economy and flexibility of the operation after refueling in nuclear power plant. The optimization design of the reload loading pattern is a very short time requirements, great difficulty, high experience requirements and repeatable work. According to these above rigorous requirements, based on statistical learning and random sampling, this study proposes an intelligent method of reload core loading pattern optimization——Probability Sampling Loading Pattern Optimization (PSLPO). This method intelligently extracts the characteristic law in the optimization space of the reload core loading pattern by statistical learning method to establish the probability model. And the probability model is embedded into PSLPO by the random sampling method. Finally, PSLPO method is constantly updated and evolved in the optimization process by intelligent means such as dynamic adjustment weight factor, probability model adaptive adjustment mechanism and combined simulated annealing design, which realizes the improvement of the optimization ability of the algorithm continuously. According to the actual reload design verification for cycle 5 of Hainan nuclear power plant unit 2, it is shown that the recommended pattern of PSLPO is better than manual search pattern in the aspect of cycle length and power distribution, and the method can intelligently give multiple design patterns, which users can have many choices. Through the optimization evaluation with a single computer core, the optimization efficiency of the method can meet the needs of core reload design. The global optimization ability can be further improved through parallelization and algorithm parameter optimization.

Evaluation of the gas turbine unit in the Kirkuk gas power plant to analyse the energy and exergy using ChemCad simulation

Abstract The purpose of the study is to evaluate the thermal performance of the gas turbine unit represented by (K3) under actual weather conditions by applying the first and second laws of thermodynamics, the design production of the unit (283.6 MW) at standard conditions (1 bar) and temperature (15) Celsius, which included the analysis of the unit energy and available energy. Hence, to find out the weaknesses and losses in the system ChemCad simulation has been used to estimate the effects of external factors (ambient temperature, compression ratio and relative humidity) for a whole year on the performance of the turbine unit. Overall results showed that the maximum exergy efficiency was obtained in November; it was ~37% when Ta was 19.39°C. The maximum efficiency obtained at Ta equal to 19.39°C, which was ~37.67%. Higher ambient temperature increases specific fuel consumption (SFC). The results show that the SFC for the practical and program calculations increases with the increase in the temperature of the external environment and reached the maximum rate in the practical calculations in September (0.224) at 33.27°C. Thus, it economically affects the price of power production. Moreover, the results showed that the combustion chamber occupied the first place for the destruction of available energy, and the results of energy efficiency and available energy were 39.20% and 30.83%, respectively.