Performance Of Coal-fired Power Plants Research Articles

Comparative investigation on the thermodynamic performance of coal-fired power plant integrating with the molten salt thermal storage system

One of the most critical challenges facing China is enhancing the operational flexibility of coal-fired power plants (CFPPs), given the increasing reliance on renewable energy for power generation. This study focuses on analyzing and comparing the molten salt thermal storage systems integrated in CFPP in consideration of peak-shaving capacity, equivalent round-trip efficiency, heat consumption rate, and exergy efficiency. Five charging schemes integrating thermal energy storage (TES), power to heat (P2H) and combination of TES and P2H are proposed and tested via their thermodynamic models. Results show that all five integrated molten salt thermal storage systems can enhance the peak shaving capability of the CFPP. When integrating P2H system, CFPP has the potential to achieve a zero-power output. Furthermore, comparing to the other four schemes, P2H-only integrating scheme has the highest equivalent round-trip efficiency of 36.23 % and the lowest heat consumption rate of 8288.87 kJ·(kW·h)−1. However, its exergy efficiency decreases to 36.51 % due to the electric heater experiencing the highest exergy loss of 132.56 MW, in contrast to the TES-coupled system which shows a higher exergy efficiency of 39.58 %. The P2H-only scheme boasts the largest investment of $33,353,100 and the longest repayment time, while also earning the highest compensation for peak shaving. This study provides a promising approach for molten salt thermal storage system designs in enhancing flexibility for CFPPs.

Analysis on temperature vacuum swing adsorption integrated with heat pump for efficient carbon capture

Carbon capture and storage (CCS) is gathering the momentum to achieve the ultimate target of carbon neutrality. Temperature vacuum swing adsorption (TVSA) has uncovered its superiority due to large working capacity, CO2 purity and recovery rate. However, high energy demand in the regeneration process of adsorbent leads to the loss of net efficiency of coal-fired power plant (CFPP) after retrofitted. This paper initially proposes and evaluates an integrated system which is composed of an adsorption carbon capture unit (ADCCU) and a single-effect absorption heat transformer (SAHT). Then a general concept of sorption carbon capture integrated with heat pump could be introduced. Results indicates that CO2 purity and recovery rate of the integrated system vary from 91.20 % to 92.75 % and from 95.62 % to 98.11 % when flowrate range from 48 NL·min−1 to 60 NL·min−1. Under the condition of 140 °C regeneration temperature of ADCCU and 80 °C generation temperature of SAHT, exergy efficiency of SAHT achieves the maximum value of 85.28 %. Moreover, a vapor compression heat pump (VCHP) system is coupled to provide moderate temperature heat for SAHT when waste heat of CFPP is inadequate. The effect of waste heat and electricity consumed on performance of CFPP is also taken into consideration. When recovery rate is lower than 27 %, performance of the proposed integrated system is more favorable than that using steam evacuated from the turbine. It is demonstrated that heat pump assisted adsorption capture for CFPP may be a promising solution to reduce energy consumption in the near future.

Thermal Performance of Coal-Fired Power Plant based on Number of Feedwater Heaters

This study aims to investigate the feasibility of using a feedwater heaters system with coal-fired power plant. Furthermore, the influence evaluation of the different coal consumption on the coal-fired power plants in terms of power output and thermal efficiency improvements. As well, this study focuses on the effect of different feedwater heaters' numbers which caused the highest exergy destruction of the coal-fired power plants. For different values of the coal consumption, a parametric study was conducted to determine the efficiency of the coal-fired power plant. The results show that, when the coal consumption increases the power output will increases too. The slight decreases in the efficiencies are due to the small differences in how the mass flow rates of different streams increase. The exergy destruction was increased by about 16% when the consumption of fuel increases by 40 kg/s. It was observed that operating the coal-fired power plant at high coal consumption leads to reduce the effective ness of the feedwater heaters and increases the power output.

Parametric Assessment of The Thermal Performance of Coal-Fired Power Plant

Exergy analysis has been found to be a useful method for improving the conversion efficiency of energy resources, since it helps to identify locations, types and true magnitudes of wastes and losses. It has also been applied for other purposes, such as distinguishing high- from low-quality energy sources or defining the engineering technological limits in designing more energy-efficient systems. To identify locations, types, and actual magnitudes of energy losses; exergy analysis has been found to be a valuable way for enhancing the conversion efficiency of the different energy systems. The aim of this research is to analyze the effect of the operation conditions on the performance of coal-fired power plants. As well, this study focuses on the effect of different feedwater heaters' numbers that lead to the highest exergy destruction of the coal-fired power plants. For different values of the superheated steam temperature and the pressure, a parametric study was conducted to determine the efficiency of the coal-fired power plant. The results show that, when the pressures and temperature of the superheated steam increases the evaporator temperature will increases too. Increasing the temperature of evaporator rises the average maximum temperature of the cycle, which improves the thermal efficiency of the cycle as well as the powerplant efficiency. The results show that, at higher boiler pressures and temperatures, the temperature difference between the water/steam and hot gases of the boiler is reduced which means the irreversibility associated with the heat transfer process decreases. Therefore, by increasing the pressure and temperature of the superheater, the exergy efficiency of the thermal cycle is improved. It was observed that operating the coal-fired power plant at high superheated pressure and temperatures produce lead to reduce the exergy losses.

An empirical analysis of the environmental performance of China’s overseas coal plants

China’s ongoing commitment to overseas infrastructure investment through the Belt and Road Initiative (BRI) has ignited concern over environmental impacts. The BRI’s environmental impacts will be determined by China’s decisions not only on what kinds of projects to fund, but also how those projects end up operating relative to projects without Chinese involvement. It is critical to understand current performance and establish a baseline understanding of the environmental impacts of China’s overseas projects thus far. We examine the environmental performance of coal-fired power plants in Asia in terms of carbon dioxide emissions intensity. Using generating unit-level data and a regression-based analysis, we estimate the comparative emissions intensity of overseas coal plants owned, designed, or constructed, by Chinese and non-Chinese companies. We find that Chinese coal plants tend to have significantly lower emissions intensity than similar non-Chinese coal plants. Given that total emissions rather than relative emissions intensity primarily drive the global warming impact of a plant, we also estimate total annual emissions and committed lifetime emissions of the plants in our dataset. We find that while Chinese plants may have relatively lower emissions intensity, their total emissions will grow as a proportion of the coal plant emissions in Asia over time.

Improving the Efficacy and Efficiency of the Environmental Management System in the Romanian Powerplants on Coal – the Condition of the Environmental Performance

After a decade-long evolution, the use of coal for energy production is growing again. Carbon is still an important source of energyin Europe, covering about one-fourth of electricity production. There are plans to open around 50 new coal-fired power plants.But the continued use of coal has a price, we pay all, mainly with our health can be affected by excessive environmental pollutionToday more and more emphasis on the concept of „green economy” that should be reflected in improving people’s lives througheffective management of environmental issues and reducing environmental risks Thus, through the present paper we aim to highlightthose aspects that would allow the improvement of the environmental performance of coal-fired power plants in Romania byimproving the efficiency and effectiveness of the Environmental Management System (EMS) as a component of the Integrated ManagementSystem along with the Quality, Health and Safety Management System . We start from the premise that the developmentand implementation of an effective and efficient environmental management system (EMS) becomes a priority for all companies inthe field , especially since their activities based on coal burning , are considered among the most polluting.

Thermodynamic modeling and performance evaluation of a supercritical coal-fired power plant situated in Western India

ABSTRACT Energy consumption in India is increasing drastically due to the increase in its population every year. In this severe condition, it is highly desirable to focus on the performance of existing and upcoming power plants in India using thermal performance analysis of each plant. The subcritical power plants are going to be replaced by supercritical power plants (SUPP) in the present scenario in the country. The present study deals with the thermal performance analysis of a 660 MW capacity coal-fired SUPP situated in western India. The thermodynamic modeling with empirical relation of each of its components is done and executed in MATLAB programming interface. The pure sliding pressure with variation in plant load is taken for constructing a semi-empirical model. The properties of steam are considered as per the IAPWS IF-97 standard. The results obtained from the simulation model are validated with actual operational data of the plant. The amount of coal consumption, steam mass flow rate, plant overall efficiency with variation in plant load is analyzed and compared with the operational data. The output obtained from the simulated program found to be satisfactory by comparing it with the actual operational plant data under study. The condenser rejects 36.42% of total heat to cooling water. The predicted steam generator efficiency of 86.04% is validated with actual steam generator efficiency. The simulated model of the SUPP will help those technologists and investigators who are putting their effort into improving the performance of coal-fired power plants.

Unified efficiency measurement of coal-fired power plants in China considering group heterogeneity and technological gaps

Abstract China's coal-fired power generation has accounted for a large proportion of the power supply for a long time and the resulting environmental pollution and waste of resources have hindered the sustainable development of the power industry. To solve this problem, this study combines the concept of natural and managerial disposability with the non-concave meta-frontier method to determine the unified efficiency measurement of 251 coal-fired power plants in China from 2012 to 2014 and to investigate the sources of inefficiency in different areas. The results show that although the unified efficiency of China's coal-fired power plants improved significantly during 2012–2014, much room for improvement remains in terms of power generation and environmental performance. Due to the advanced technology of coal-fired power plants, the eastern area has the highest unified efficiency in terms of natural and managerial disposability. The western region has the lowest operational performance and the northeast region has the lowest environmental performance. The decomposition of the sources of inefficiency indicates that the inefficiency of coal-fired power plants in eastern China is mainly caused by management factors, whereas the inefficiency in northeastern China is due to a lag in technology. In the central and western areas, technical inefficiency and management inefficiency both account for a considerable proportion in their sources of inefficiency. Therefore, these regions need to improve both the management (e.g., reasonable allocation of utilization hours) and technology (e.g., clean coal technology) aspects to improve the unified performance of coal-fired power plants.

Cost and environmental efficiency of U.S. electricity generation: Accounting for heterogeneous inputs and transportation costs

In this paper we conduct an empirical analysis of the environmental and economic performance of coal-fired power plants in the United States. Using nonparametric methods for efficiency analysis we propose a theoretical framework that builds upon the restrictions of mass balances for production possibilities and explicitly takes into account heterogeneous fuel quality and prices of the fuel input. This heterogeneity influences both the cost of the production and the emission of environmentally harmful pollutants. Moreover, we analyze how the incorporation of transportation costs influences the cost efficiency of the electricity generating units and quantify the trade-off between environmentally efficient and cost-minimizing production of electricity.

Study on the performance of coal-fired power plant integrated with Ca-looping CO2 capture system with recarbonation process

This paper studies the performance of a coal-fired power plant integrated with Ca-looping CO2 capture system with recarbonation process. The Ca-looping CO2 capture system with/without the recarbonation process are simulated using the ASPEN PLUS™ software and integrated in a coal-fired power plant with the net system efficiency of 41.57%. Simulation results of the two systems are compared, and a sensitivity analysis of the key parameters is taken. The results show that, when the CO2 capture rate is 85%, the net system efficiency of the coal-fired power plant integrated with the traditional Ca-looping CO2 capture system without recarbonation process is 30.66%. The efficiency penalty is 10.91% compared with that of the benchmark coal-fired power plant without CO2 capture. While the net efficiency of the coal-fired power plant integrated with the Ca-looping CO2 capture system with recarbonation process is 34.3% and the efficiency penalty is only 7.27%. The analysis results show that reducing the amounts of both calcium sorbents and the fresh sorbent supplement in cycles can further improve the efficiency of the overall system. The achievements from this paper will provide the valuable reference for the CO2 capture from the coal-fired power plant with lower energy consumption.

Appropriate feed-in tariff of solar–coal hybrid power plant for China’s Inner Mongolia Region

Middle-temperature solar heat can be used to preheat feed water before it enters the boiler in a coal-fired power plant. Previous studies have shown that this approach can improve the performance of coal-fired power plants. The present study estimates the first solar–coal hybrid power plant in the Inner Mongolia Region. It will have a potential net solar power output of 10MW on the basis of the operating data of a traditional 200MW coal-fired power plant. Economic feasibility analysis is then performed on the solar–coal hybrid power plant. The appropriate feed-in tariff prices are provided on the basis of different financing scenarios, solar field cost, collector area size, and other conditions. The results obtained in this study are expected to provide suggestions for the further development of solar–coal hybrid technology.

Thermodynamic Modeling and Validation of a 210-MW Capacity Coal-Fired Power Plant

This paper presents the thermodynamic modeling and validation of a 210-MW subcritical coal-fired power plant situated in North India. In the era of high computing facilities available, modeling and simulation have become a very pertinent tool for design and development. As such, the objective of the present work is not to enhance the thermal conversion efficiency, but to represent the thermal system in a simplistic yet functional manner. The thermal performance module consists of the following main sections such as steam boiler, economizer, superheater, reheater, steam turbine, condensate extraction pump, boiler feed pump, feedwater heaters and condenser. Thus, a semi-empirical module has been developed to predict thermal performance of coal-fired power plant. It includes the mass balance, energy balance, thermodynamic property relations for working substance followed by empirical correlations for steam bled pressure and thermodynamics of a steam power cycle. By using the MATLAB calculation tool, a process-based computer program of the coal-fired power plant has been successfully validated for thermal efficiency, steam flow rate and coal consumption rate at wide plant load range. The predictions were compared with operating data of 210-MW thermal power plant at different power output levels. The predicted results agree with plant operating data.

Undesirable congestion under natural disposability and desirable congestion under managerial disposability in U.S. electric power industry measured by DEA environmental assessment

This study discusses a new use of DEA environmental assessment to measure a possible occurrence of desirable congestion, or eco-technology innovation, in electric power plants. The phenomenon is compared with an occurrence of undesirable congestion in this study. The identification of undesirable congestion is important to avoid a cost increase and a shortage of generation. However, the identification of desirable congestion is much more important than that of undesirable congestion from the perspective of environmental assessment. This study looks for a sustainable economic growth by identifying eco-technology innovation that can be effectively used to reduce the amount of air pollution so that electric power companies satisfy a governmental standard on environmental protection. The proposed approach is applied to evaluate the performance of coal-fired power plants in the United States. This study finds two policy implications. First, power plants operated by bituminous coal (i.e., black coal) outperform those with sub-bituminous coal (i.e., brawn coal). The result implies that power plants with sub-bituminous coal should be replaced by bituminous coal. Second, the undesirable congestion, due to a line limit between points of power generation and consumption, may occur on most of coal-fired power plants. In contrast, desirable congestion, due to eco-technology innovation, may occur on a limited number of power plants. Thus, the identification of desirable congestion assists us in selecting which technology, or the type of power plant, should be invested to facilitate eco-technology innovation and its related engineering management for a future sustainable economic growth.

Evaluation and Modeling of Part-Load Performance of Coal-Fired Power Plant with Postcombustion CO2 Capture

The share of the fossil-fuel power systems in the European Union energy portfolio has recently increased, even with new environmental incentives aimed at the reduction of CO2 emissions from the power sector. Implementation of carbon capture technologies has been identified as a critical step toward reduction of CO2 emissions. As the power plants usually operate with changing loads to meet the electricity demand, it is important to evaluate the process performance under different operating loads. Therefore, this study provides a methodology for modeling of part-load operation of coal-fired power plants in a process simulator, such as Aspen Plus. The part-load power plant model is validated using data from the literature, and it was demonstrated that a maximum discrepancy of 5% was obtained for the live steam pressure prediction at 40% load, while the discrepancy for all other compared parameters at other loads did not exceed 3%. Furthermore, the part-load model is used to evaluate the performance of the retrofitted power plant with the CO2 capture plant at different loads, with monoethanolamine as a solvent, revealing that the net efficiency varied between 28.2%HHV and 21.1%HHV. Moreover, the analysis showed that neglecting the off-design conditions due to steam extraction would result in overestimating the net thermal efficiency by up to 1.3%HHV points at 100% load operation and steam extracted at 11.9 bar.

Environmental assessment on coal-fired power plants in U.S. north-east region by DEA non-radial measurement

This study discusses a new use of DEA (Data Envelopment Analysis) environmental assessment to measure unified (operational and environmental) and scale efficiencies among inputs, desirable and undesirable outputs. In particular, the measurement of scale efficiency is discussed by two non-radial models. That is a new methodological contribution. To discuss these efficiency measures, this study first examines a concept of disposability from the perspective of corporate strategies to adapt a regulation change on undesirable outputs. The concept is separated into natural and managerial disposability. After discussing how to measure the degree of scale efficiency within the non-radial approach, this study applies the proposed DEA environmental assessment to measure the performance of coal-fired power plants in the U.S. north-east region. The region has been long producing a large amount of coal from the Appalachian Mountains. The coal mining industry has supported U.S. energy utility and other industries. Because of the long history, the quality of coal became worse and the coal-fired power plants have been producing a large amount of undesirable gases. This study has statistically confirmed that there is a significant difference between the two types (BIT: bituminous coal and SUB: subbituminous coal) of coal-fired power plants in terms of their unified efficiency measures, including their scale efficiencies, under the concept of managerial disposability (the first priority: environment performance and the second priority: operational performance). In contrast, under the natural disposability (the first priority: operational performance and the second priority: environmental performance), this study cannot find such a statistical significance between them. The fact, in which BIT outperforms SUB in terms of their unified and scale efficiencies, suggests the policy implication that these power plants need to shift their coal combustions from SUB to BIT in the United States. Besides the empirical finding, this study cannot confirm the other hypothesis on whether coal-fired power plants with small operation (less than 50% in plant capacity factor) outperform ones with large operation (more than 50% in plant capacity factor), and vice versa, in terms of their unified and scale efficiency measures under natural and managerial disposability. An exception is found in environmental performance under variable returns to scale. The rationale is because their plant operations are frequently monitored by regulatory agencies. As a consequence, this study cannot find such a statistical difference between them on operational performance. This result implies that the regulation on coal-fired power plants has been effective on their unified performance but large power plants may have a potential to improve their environmental performance.

Off-design thermodynamic performances on typical days of a 330 MW solar aided coal-fired power plant in China

The contribution of mid-temperature solar thermal power to improve the performance of coal-fired power plant is analyzed in the present paper. In the solar aided coal-fired power plant, solar heat at<300°C is used to replace the extracted steam from the steam turbine to heat the feed water. In this way, the steam that was to be extracted could consequently expand in the steam turbine to boost output power. The advantages of a solar aided coal-fired power plant in design condition have been discussed by several researchers. However, thermodynamic performances on off-design operation have not been well discussed until now. In this paper, a typical 330MW coal-fired power plant in Sinkiang Province of China is selected as the case study to demonstrate the advantages of the solar aided coal-fired power plant under off-design conditions. Hourly thermodynamic performances are analyzed on typical days under partial load. The effects of several operational parameters, such as solar irradiation intensity, incident angle, flow rate of thermal oil, on the performance of solar field efficiency and net solar-to-electricity efficiency were examined. Possible schemes have been proposed for improving the solar aided coal-fired power plant on off-design operation. The results obtained in the current study could provide a promising approach to solve the poor thermodynamic performance of solar thermal power plant and also offer a basis for the practical operation of MW-scale solar aided coal-fired power plant.

Economic analysis of amine based carbon dioxide capture system with bi-pressure stripper in supercritical coal-fired power plant

Post-combustion CO2 capture and storage is among the most mature technologies to capture, compress, transport and store CO2 from flue gas in coal-fired power plant. This paper presents the simulation of monoethanolamine (MEA) based CO2 capture and compression process integrated within a 600MWe supercritical coal-fired power plant using chemical process simulators. Comparison between bi-pressure stripper and single-pressure stripper reveals that improved CO2 capture system with bi-pressure stripper minimizes energy penalty of CO2 capture and compression by up to 6.3% at full unit load. The study also explores optimization of some important process parameters affecting the performance of coal-fired power plant by taking into account both CO2 capture process and CO2 compression at full unit load. These parameters include operating stripper pressure, CO2 capture efficiency and steam extraction location. Results show that the optimal stripper pressure is within the range of 1.9–2.1bar and feasible CO2 capture efficiency is between 60% and 90%. Results also show that low-pressure steam extraction reduces energy penalty. Evaluation of improved CO2 capture system is also performed at part flue gas load ranging from 40% to 90%. The study reveals that operating at part flue gas load, as compared with full load, increases energy penalty of carbon capture. Not only energy penalty but also lean solution flow rate and plant efficiency are studied at different flue load levels in this paper. In addition, results show that bi-pressure stripper configuration is also effective in reducing energy penalty at part unit load.

Expert elicitation of cost, performance, and RD&amp;D budgets for coal power with CCS

There is uncertainty about the ex-ante returns to research, development, and demonstration programs in the United States on carbon capture and sequestration (CCS) technology. To quantify this uncertainty, we conducted a written expert elicitation of thirteen experts in fossil power and CCS technologies from the government, academia, and the private sector. We asked experts to provide their recommended budget and allocation of RD&D funds by specific fossil power and CCS technology and type of RD&D activity (i.e. basic research, applied research, pilot plants, and demonstration plants) for the United States. The elicitation instrument was structured around estimating the cost and performance of coal-fired power plants with and without CCS in the years 2010 and 2030 under four funding scenarios for federal fossil energy RD&D in the USA. The most important areas identified for basic research were chemical looping combustion and membrane technology. The most important area for commercial demonstration was integrated gasification combined cycle (IGCC). There was substantial disagreement between experts on both the current and future capital cost to build a new coal-fired power plant with CCS. There was also disagreement across experts as to whether the capital cost of a new coal plant with CCS would increase or decrease if federal RD&D funding stayed constant at current levels. However, there was a consensus among our experts that accelerated federal RD&D would (weakly) lower the capital cost requirements for a new coal plant with CCS. On average, experts estimated that if their recommended RD&D portfolio was implemented, the capital cost of new coal plants with CCS in 2030 would decrease by 10% in addition to the cost reductions/increases that would occur by 2030 through non-public RD&D related factors.

Performance analysis of US coal-fired power plants by measuring three DEA efficiencies

Data Envelopment Analysis (DEA) has been widely used for performance evaluation of many organizations in private and public sectors. This study proposes a new DEA approach to evaluate the operational, environmental and both-unified performance of coal-fired power plants that are currently operating under the US Clean Air Act (CAA). The economic activities of power plants examined by this study are characterized by four inputs, a desirable (good) output and three undesirable (bad) outputs. This study uses Range-Adjusted Measure (RAM) because it can easily incorporate both desirable and undesirable outputs in the unified analytical structure. The output unification proposed in this study has been never investigated in the previous DEA studies even though such a unified measure is essential in guiding policy makers and corporate leaders. Using the proposed DEA approach, this study finds three important policy implications. First, the CAA has been increasingly effective on their environmental protection. The increased environmental performance leads to the enhancement of the unified efficiency. Second, the market liberalization/deregulation was an important business trend in the electric power industry. Such a business trend was legally prepared by US Energy Policy Act (EPAct). According to the level of the market liberalization, the United States is classified into regulated and deregulated states. This study finds that the operational and unified performance of coal-fired power plants in the regulated states outperforms those of the deregulated states because the investment on coal-fired power plants in the regulated states can be utilized as a financial tool under the rate-of-return criterion of regulation. The power plants in the deregulated states do not have such a regulation premium. Finally, plant managers need to balance between their environmental performance and operational efficiency.