Energy Efficiency Of Power Plants Research Articles

A comparative study of polyamine and piperazine as promoter for CO2 absorption performance in aqueous methyldiethanolamine blend system: 430 MW power plant data simulation and economic assessment

Fossil fuel power plants play a significant role in fulfilling global energy demands but are also responsible for high CO2 emissions. Amine-based post-combustion CO2 capture (PCC) is one of the technologies used in such power plants to reduce CO2 emissions. However, high energy consumption in amine-based PCC technology causes a reduction in the overall energy efficiency of power plants. The energy consumption significantly depends on the solvents used in the PCC process. Therefore, in this work, we performed CO2 absorption in the piperazine (PZ), triethylenetetramine (TETA), and N-methyldiethanolamine (MDEA) blend and tri-blend solvents. For the absorption performance and energy consumption calculation, a simulation is performed for the 430 MW power plant data in the DWSIM software. Initially, solvent screening was done, and four solvents are selected based on the optimum energy consumption of various solvents. Further, the solvents’ performance in terms of energy consumption is done based on the effect of different temperatures, CO2 composition in feed, and %CO2 recovery. Overall, the TETA+PZ MDEA tri-blend solvent showed optimum energy consumption for most of the conditions. Additionally, a techno-economy assessment was done considering annual capital cost and annual operating cost, and results revealed that the cost per ton of CO2 capture in 5 %TETA+ 5 %PZ+ 20 %MDEA solvent is 27.33 % lesser than industrial MEA solvent, and 1.56 % lower than 10 %PZ+ 20 %MDEA.

Comprehensive energy efficiency analysis of ultra-supercritical thermal power units

At present, ultra-supercritical power plant is the most advanced technology, which can achieve ultra-low pollutant emissions and greatly improve the energy efficiency of power plant. In this paper, the key factors affecting the energy efficiency of thermal power unit are analyzed. Moreover, the way in which these factors affect the energy efficiency of thermal power unit is obtained. Besides, this study lay a solid foundation for subsequent improvements in the energy efficiency of thermal power unit. First, a mathematical mechanism model of ultra-supercritical thermal power units is established. In addition, Aspen Plus software is used to build a full process simulation model of thermal power unit. In addition, a methodology for energy efficiency analysis based on the exergy balance theory is presented, and energy efficiency evaluation indicators are defined. Finally, the TOPSIS method was used to rank the key factors affecting the energy efficiency of thermal power unit. Based on experimental analysis, this study found that in comparison to general unit, the ultra-supercritical thermal power units has improved boiler efficiency by approximately 2%, power generation efficiency by approximately 6.77%, carbon emissions by approximately 0.027 t/h and the exergy efficiency by approximately 2.91%, providing better energy efficiency and lower carbon emissions.

Review of Closed SCO2 and Semi-Closed Oxy–Fuel Combustion Power Cycles for Multi-Scale Power Generation in Terms of Energy, Ecology and Economic Efficiency

Today, with the increases in organic fuel prices and growing legislative restrictions aimed at increasing environmental safety and reducing our carbon footprint, the task of increasing thermal power plant efficiency is becoming more and more topical. Transforming combusting fuel thermal energy into electric power more efficiently will allow the reduction of the fuel cost fraction in the cost structure and decrease harmful emissions, especially greenhouse gases, as less fuel will be consumed. There are traditional ways of improving thermal power plant energy efficiency: increasing turbine inlet temperature and utilizing exhaust heat. An alternative way to improve energy efficiency is the use of supercritical CO2 power cycles, which have a number of advantages over traditional ones due to carbon dioxide’s thermophysical properties. In particular, the use of carbon dioxide allows increasing efficiency by reducing compression and friction losses in the wheel spaces of the turbines; in addition, it is known that CO2 turbomachinery has smaller dimensions compared to traditional steam and gas turbines of similar capacity. Furthermore, semi-closed oxy–fuel combustion power cycles can reduce greenhouse gases emissions by many times; at the same time, they have characteristics of efficiency and specific capital costs comparable with traditional cycles. Given the high volatility of fuel prices, as well as the rising prices of carbon dioxide emission allowances, changes in efficiency, capital costs and specific greenhouse gas emissions can lead to a change in the cost of electricity generation. In this paper, key closed and semi-closed supercritical CO2 combustion power cycles and their promising modifications are considered from the point of view of energy, economic and environmental efficiency; the cycles that are optimal in terms of technical and economic characteristics are identified among those considered.

Fuel consumption monitoring of power plants based on the recording of current power values

Among the main methods of increasing the energy efficiency of power plants, the most significant in terms of achieving positive results and the possibility of their implementation are organizational methods. When choosing a methodology for determining the energy efficiency of a ship's power plant, it is necessary to take into account a combination of the following necessary conditions: ensuring control taking into account stochastic changes in the current fuel consumption values ​ ​ and minimizing the cost of purchasing and using control tools. Solving these two problems is an interconnected process. With respect to diesel generator sets, this is achieved by continuously measuring the current values at each of the three phases of the generator and the voltage in a short time interval in a discrete manner, followed by calculating the current power consumption values and approximating them to energy efficiency indicators. Tests of a prototype of an analytical energy efficiency control system implementing the proposed control algorithm on a transport diesel showed a sufficiently high correlation of the obtained results with data on monitoring fuel consumption by a volumetric method, satisfactory reliability of the system, as well as the possibility of saving fuel and energy resources. A further development of the proposed approach to energy efficiency control can be the use for these purposes of the current values ​ ​ of the torque and power of the diesel engine obtained by analyzing the dynamic characteristics of the torsional and oscillatory systems of marine power plants.

Energy Analysis of Diesel Engine With B30 at PLTD Selat Panjang

Many efforts have been made in energy efficiency in power plants. One way to improve the efficiency of energy use is to conduct analysis. The purpose of this study was to analyze the thermal efficiency of a diesel engine with B30 at PLTD Selat Panjang unit 4. The data were collected using a daily operation report log sheet for Caterpillar 3512B diesel with duration 3x24. From the calculation carried out, the average thermal efficiency of diesel engine with B30 as fuel at PLTD Selat Panjang was 47.52%.

Novel Approach to Energy Management via Performance Shaping Factors in燩ower Plants

The literature that a lack of integration between the performance shaping factors (PSFs) and the energy management performance (EMP) is one of the critical problems that prevent performance improvement and reduces the power plant’s efficiency. To solve this problem, this article aims to achieve two main objectives: (1) Systematically investigate and identify the critical success factors (CSFs) for integration with PSFs and EMP; (2) Develop a novel modelling approach to predict the performance of power plants based on innovative integrated strategies. The research methodology is grounded on the theoretical and practical approach to improving performance. The Newcastle Ottawa Scale (NOS) was used to assess the quality of the literature that met the criteria. To ensure the reliability and accuracy of the proposed model, the researchers developed a hypothesis and evaluated the CSFs via a case study in the Iraqi power plants. The findings of this study succeeded in developing a novel modeling approach to predict the performance by integrating the CSFs of both the PSFs and EMP to increase the positive interaction and energy efficiency of power plants. The results confirmed the validity of the selected hypotheses and verified the positive and important relationship with the success and improvement of the performance in power plants. However, the lack of consistency and balance in the current studies indicates that the performance strategy in power plants did not receive sufficient attention and needs further investigations.

Individual Heat Substations Integrated with Heat Pumps for District Heating Systems in Ukraine

Energy systems around the world require a sustainable way for energy supply that does not add carbon to the atmosphere and thus does not enlarge the greenhouse effect, which is seen nowadays as the main cause of climate change. Urban housing consumes the most energy in European countries accounting for up to 43 % of final energy, while 65 % of it is spent on house heating and hot tap water supply. The reduction of carbon dioxide emissions and increasing of energy efficiency of power plants in Ukrainian cities, where district heating systems are centralised, and heat carriers are supplied from central combined heat and power stations based on fossil fuels, can be performed by modifying the existing district heating systems. One of the promising ways is the transition to low-temperature heat carriers from combined heat and power stations, which suppose the use of renewable energy sources, which can be integrated with individual heat substations of houses, and should satisfy the needs of residents in heating and hot water, with the possibility of air conditioning. In the present work, the possible implementation of individual heat substations integrated with heat pumps for low-temperature district heating systems is discussed. The analysis of the possibilities to increase the energy efficiency of the dormitory building with old construction is provided. The method for the design of individual heat substations for heating and hot water supply systems is discussed, including the recommendations for the building renovation.

Evaluation of Optimal Occasional Tilt on Photovoltaic Power Plant Energy Efficiency and Land Use Requirements, Iran

The paper studies the optimum panel horizontal orientation angle toward the Sun and the optimum time interval of the panel’s movement. The optimum time intervals or panel movement can change the rate of input energy to the panel surface in Iran. For this purpose, a neural network has been trained to estimate the intensity of solar radiation in Iran. After model validation, the intensity of solar radiation has been estimated by selecting adequate geographical regions. Based on the intensity of sunlight, Iran has been divided into ten regions. In these regions, 40 cities have been randomly selected to study the effect of the panel’s angle variations within appropriate time intervals, as well as equal time intervals. The results show that the choice of the mounting system with the possibility of five angles’ implementation can increase the amount of solar energy between 3.9% and 7.4%. Compared to this number of angles at the equal time intervals, the amount of incoming solar energy has increased by 3% to 7%. In the first and second cases, the area of the power plant increases by about 12% to 24% compared to the yearly optimum tilt angle. Moreover, the amount of radiation incoming to the panel with the optimum operating angle is in alignment with the results of PVsyst software.

Technical, economic, and environmental analyses of CCHP systems with waste incineration power plant as prime mover

ABSTRACT In recent years, population growth and community development have increased the volume of waste in many parts of the world, including in Iran. If management measures are not taken to reduce the volume of waste at the surface, the problem of increasing waste will become a major and serious threat to human life. Therefore, incineration plants will be built to reduce the volume of waste, which have potential to generate power. Accordingly, the purpose of the present study is potential analysis of exhaust gases from the incineration plant for use in the combined cooling, heating, and power system, as well as the environmental analysis of the power plant. Using Aspen software, an initial model of the trigeneration cycle power plant is designed and the layout and arrangement of the cycle are accomplished. The mass flow of waste consumed at the power plant is 8333 kg/h and power generation is 3 MW. Heat losses from boiler exhaust gases are inserted into a heat exchanger modeled by EES software to meet the heat requirement. The heat exchanger efficiency is 70%, and the outlet water temperature is calculated as 70°C. The exhaust gases from the heat exchanger have been fed into the water-ammonia absorption chiller to meet the cooling requirement. The cooling capacity of the first evaporator is 1111 kW and for the second evaporator, it is calculated to be 529 kW. The power plant energy efficiency is 35%, and when it is converted into a combined cooling, heating, and power (CCHP) system the total efficiency of the system increases by 70%. The economic feasibility of the project has been checked, and the payback period has been estimated to be about 2.5 years. This study shows that CCHP systems using incineration plants as prime movers can play an important role in providing energy requirements and sustainable development.

Experimental investigation of the microclimate effects on floating solar power plant energy efficiency

Experimental investigation of the microclimate effects on floating solar power plant energy efficiency

Development of Co3-xNixO4 materials for thermochemical energy storage at lower red-ox temperature

Heat storage technologies are subject of great research efforts aimed at improving the energy efficiency of power plants and heat recovery processes. In this context, the development of highly efficient and low-cost materials for thermal energy storage is imperative for a large use of this technology. The storage of thermal energy using reversible thermo-chemical reactions can provide large storage capacities especially at high temperatures. Within this class of materials, the red-ox reactions have particular interest due to the low cost of the materials involved (metal oxides) and the use of air both as reacting gas and heat transfer fluid. Therefore, many efforts are doing to improve the efficiency and reversibility of this type of reactions. In this work the synthesis and thermal performances of a novel mixed metal oxide based on cobalt/nickel metals with spinel structure Co3-xNixO4 is reported. A deep study was carried out in order to find the best synthesis conditions and optimum relative metal content in the structure with the objective of decreasing as much as possible the red-ox temperature. The study allowed to determine the optimum Ni content in the oxide structure in order to minimize the reaction temperature. In particular, a linear relationship of the red-ox temperature as a function of the Ni content was observed, enabling reaching red-ox temperature below 700 °C. These results are very promising and open the perspective of using of these types of materials to a wider field of application.

Energy efficiency of power plants meeting multiple requirements and comparative study of different carbon tax scenarios in Thailand

The most recent power generation policy adopted by the government of Thailand focusses on three different areas: security, to ensure a stable power supply; economy, to ensure that the costs associated with implementation of facilities is appropriate; and ecology, to reduce environmental emissions and social impacts. In order to address these requirements, this study proposes a practical model modification for assessing the energy efficiency of power plants. Specifically, stochastic frontier analysis (SFA) with inefficiency effects was applied to both renewable energy and fossil fuel-fired power plants in Thailand. The empirical results showed that power plant capacity was positively correlated with plant efficiency, and that plant age was negatively correlated with efficiency. In addition, in terms of efficiency scores, renewable power plants tended to be 7.13% more efficient than fossil-fuel plants, and base-load power plants were 9.44% more efficient than peak-load plants. In addition, the efficacy of four different carbon tax scenarios and their effects on the technical efficiency of power plants were evaluated. The results of the tax-rate analysis demonstrated that even low carbon taxes (e.g., 1 USD/tCO2e) can encourage the notable cleaner energy system.

Undesirable factors in stochastic DEA cross-efficiency evaluation: An application to thermal power plant energy efficiency

In this study using an input-oriented data envelopment analysis (DEA) model with undesirable outputs a new stochastic model called Expected Ranking Criterion is proposed. The proposed model employs statistical techniques to evaluate the efficiency of decision making units (DMUs) with stochastic data. Based on the proposed model, a stochastic DEA (SDEA) cross-efficiency model is suggested for ranking and discrimination of DMUs. Then, given the non-uniqueness of resulting optimal solution, a stochastic model is introduced for rating priorities by which cross-efficiency evaluation is performed using aggressive approach. Finally, the proposed models are implemented for evaluating 32 thermal power plants. The results show the applicability of the proposed models.

Energy saving technologies and energy efficiency of motor transport power plants

The perspective energy sources alternative to hydrocarbons, which are currently used in the world, are considered. Energy-saving technologies for the use of hydrocarbon fuel in vehicles are analyzed.
 The need to develop the use of electric drives on automobiles is noted. The importance of systematical accumulation and analyzing of the existing experience of operating vehicles with electric drives abroad and in the Russian Federation is considered. Monitoring the technologies developed abroad and the problems arising during the operation of electric vehicles will make it possible to determine the priority ways of their development and to concentrate the efforts of researchers in the direction ensuring the maximum efficiency of their application.
 One of the currently attractive and economically viable ways of developing road transport for domestic practice is the use of vehicles with hybrid power plants. It is shown that the production of hybrid vehicles and electric vehicles abroad is successfully developing and is nowadays one of the most dynamic in the world.
 Indicators of efficiency of electric power consumption of vehicles with electric drive of various automobile manufacturers are given. A comparative analysis of technologies for the use of electric automobiles to improve the environmental situation in megalopolises is carried out and the problems of increasing the efficiency of automobile power plants are considered.
 It is shown that the climatic conditions of the Russian Federation with long periods of low temperatures of atmospheric air strongly affect the energy losses associated with heating the passenger compartment, and to a large extent - on the energy efficiency of the power plant of electric vehicles.
 To assess the efficiency of using electric vehicles, it is proposed to use a universal indicator of the efficiency of energy consumption. It is proposed to carry out a comparative assessment of the energy consumption of various vehicles by the energy parameter qEL.
 The calculated data show that the use of vehicles with electric drive and, in particular, rechargeable hybrids is more profitable in comparison with the use of vehicles equipped exclusively with internal combustion engines.

Повышение энергоэффективности силовых электроэнергетических установок малотоннажных пассажирских судов

The article is devoted to solving the problem of improving the energy efficiency of power plants of high-speed lowtonnage (planing) vessels used for passenger transportation between coastal settlements on the example of the port of Vladivostok located on the Muravyov-Amursky Peninsula, which has mainly land communication with settlements located on the coast. The oversaturation of motor transport, due to the need for communication between localities, which are usually characterized by dense buildings, is one of the main causes of many hours of traffic congestion, which worsen the environmental situation and increase social tension in society. At the same time, the tourist attractiveness of Primorye is also decreasing. One of the promising areas for solving this transport problem is the use of low-tonnage passenger vessels, in particular planing vessels, with hybrid electrified power propulsion systems. According to the available data, such vessels have reduced consumption of fuel and lubricants necessary for the operation of power plants and reduction in harmful emissions into the surrounding atmosphere by more than two times compared to similar traditional diesel vessels. In addition, the prospects of the proposed scientific and technical solution are due to the reduction in the time of passenger transportation while reducing the cost of travel

Improving the energy efficiency of a solar power plant

The urgency of the work is due to the feasibility of increasing the energy efficiency of solar power plants through the use of solar energy concentrators. Ways to improve the energy efficiency of solar panels using a sys-tem of directional mirrors, flat Fresnel lenses, spherical concentrators and trackers have been investigated. It is established that the most optimal way to improve the energy efficiency of solar panels is to use inexpensive track-ers with a simple design. The analysis of known types of solar panels, which differ in materials from which their elements are made, and the coefficients of efficiency – dependence of energy produced by a photocell on the intensity of solar radiation per unit of its surface has been carried out, and the type of solar panels by the criterion “price-quality” has been selected. A tracker design has been developed to track the angle of inclination of solar panels to increase efficiency. The electricity generated by the proposed solar power plant was calculated using an online calculator. It is projected to reduce losses when generating electricity for a given power plant due to the use of a tracker compared to a fixed power system, with the same number of solar panels. In order to reduce the cost of the tracker, it is suggested to orientate it to the south at once, and to change the inclination angles twice a year (in early April and late August). The energy efficiency of the power plant is calculated in two stages. At the first stage the amount of electricity from solar panels per year when adjusting only the angle of inclination of the panels to the south is calculated. At the second stage energy efficiency of the power plant is calculated taking into account the increase of energy efficiency of the solar power plant when using the tracker system. The calculated electricity generation of the proposed solar power plant with tracker confirmed the efficiency and feasibility of using the designed tracker system. The application of the designed tracker system allows to increase the energy efficiency of solar panels by an average of 25%.

Optimisation and thermo-mechanical analysis of a coated steam dual pipe system for use in advanced ultra-supercritical power plant

Improving the energy efficiency of power plants by increasing steam operating temperature up to 700 °C can be achieved using novel engineering design concepts such as coated steam pipe systems. This paper presents an optimised design for a novel coated dual pipe system to be used in advanced ultra-supercritical power plant. The approach developed in this study uses a combination of an optimisation algorithm and FE simulation, based on the reduction of the hoop stress at top coat/bond coat interface generated by the thermal and mechanical stresses. This allows determination of the optimum dimensions and material properties of the system. A unified viscoplastic model which combines a power flow rule with non-linear anisothermal evolution of isotropic and kinematic hardening has been used for the thermo-mechanical analysis of the coated dual pipe system under the cyclic loading. The results of the optimisation show that the value of the hoop stress at the top coat/bond coat interface is reduced significantly, compared with that in the baseline model. Finally, the potential technical challenges and future works for the proposed steam dual pipe system are discussed.

A universal Bayesian inference framework for complicated creep constitutive equations

Evaluating the creep deformation process of heat-resistant steels is important for improving the energy efficiency of power plants by increasing the operating temperature. There is an analysis framework that estimates the rupture time of this process by regressing the strain–time relationship of the creep process using a regression model called the creep constitutive equation. Because many creep constitutive equations have been proposed, it is important to construct a framework to determine which one is best for the creep processes of different steel types at various temperatures and stresses. A Bayesian model selection framework is one of the best frameworks for evaluating the constitutive equations. In previous studies, approximate-expression methods such as the Laplace approximation were used to develop the Bayesian model selection frameworks for creep. Such frameworks are not applicable to creep constitutive equations or data that violate the assumption of the approximation. In this study, we propose a universal Bayesian model selection framework for creep that is applicable to the evaluation of various types of creep constitutive equations. Using the replica exchange Monte Carlo method, we develop a Bayesian model selection framework for creep without an approximate-expression method. To assess the effectiveness of the proposed framework, we applied it to the evaluation of a creep constitutive equation called the Kimura model, which is difficult to evaluate by existing frameworks. Through a model evaluation using the creep measurement data of Grade 91 steel, we confirmed that our proposed framework gives a more reasonable evaluation of the Kimura model than existing frameworks. Investigating the posterior distribution obtained by the proposed framework, we also found a model candidate that could improve the Kimura model.

New Engineering Solutions for the Traction Electric Drive of a Gazelle-Next Medium-Duty Van

A procedure for choosing the optimal gear ratio for a reducing gear train is proposed for the traction electric drive of the workshop electric automobile based on the GAZ A22R22/32 chassis and its modified versions, taking into account the requirements for the top linear speed of the automobile, acceleration, and power plant energy efficiency that will allow achieving a required reserve. The optimization procedure consists of three phases. In phase one, the traction electric drive’s top speed was achieved. Then, the time was minimized for which the electric drive reached the rated speed. In phase two, the gear ratio was adjusted proceeding from the conditions in which the drive was used in the field attenuation zone. Taking into account the system’s operation in the attenuation mode against the loss minimization criteria, the procedure of selecting the gear ratio allowed reaching a cruising range of 200 km and the traction electric drive’s acceleration to the rated speed in 9 s. A charge control system is proposed that allows making the battery work stably in operational and charge modes. It is confirmed by experiment that, at a cell imbalance of no more than 3%, the full balancing takes only up to 4 min.

Improvement of tribological characteristics of rubbing surfaces as one of ways to increase energy efficiency of power plants

In this study, the team of authors solves the problem of increasing the energy efficiency of power plants by reducing losses while lowering the coefficient of friction. This problem is solved with the help of a multifunctional additive to lubricating oils, which are a surface-active substance (surfactant) capable of changing the friction conditions of contacting surfaces in a small amount when introduced into tribological units. The tests were carried out on a friction machine II5018 on a block-roller friction pair (the material of the roller is gray cast iron SCh20, the material of the block is steel 65). During the study, the moment and coefficient of friction were determined. A friction coefficient decrease of up to 50 % was obtained, which proves the effectiveness of the proposed compositions.