Developing an analytical model to predict the energy and exergy based performances of a coal-fired thermal power plant

Khaleel, Omar J.; Ibrahim, Thamir K.; Ismail, Firas Basim; Al-Sammarraie, Ahmed T.

doi:10.1016/j.csite.2021.101519

Cited by 29 publications

(5 citation statements)

References 23 publications

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“…Specifically, the maximum ramping rate is R I u when P TPUR,min u ≤ P TPU u,t ≤ P TPU,max u , and R II u when P TPUD,min u ≤ P TPU u,t ≤ P TPUR,min u . The variation in maximum ramping rates is attributable to the fact that a reduction in TPU output during the DPR state can lead to increased losses and diminished performance [31]. Moreover, Equation (13) also clarifies that the ramping constraints do not affect the on-off transitions of the TPU between adjacent time steps; these on-off transitions are only permissible within a certain output range.…”

Section: Constraintsmentioning

confidence: 98%

Enhancing Renewable Energy Accommodation by Coupling Integration Optimization with Flexible Retrofitted Thermal Power Plant

Zou,

Xia,

Chi

et al. 2024

Applied Sciences

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Thermal power units (TPUs) play a crucial role in accommodating the high penetration of renewable energy sources (RESs) like wind turbines (WTs) and photovoltaics (PVs). This paper proposes an evaluation framework to quantitatively analyze the flexibility potential of retrofitted TPUs in enhancing the accommodate capability of RESs through coupling integration and optimal scheduling. Firstly, the coordination framework for coupling TPUs with RESs is outlined, including a comprehensive analysis of benefits and implementation strategies. Secondly, an annual optimal scheduling model for TPUs and RESs is developed, incorporating deep peak regulation services, ladder-type constraints for retrofitted TPUs, and their operational characteristics before and after the coupling integration. Thirdly, indices to evaluate RES accommodation levels and TPU regulation capacities are proposed to quantify the performance of power sources. Finally, a real-world case study is conducted to demonstrate that integrating retrofitted TPUs with RESs through coupling significantly enhances RES utilization by 3.6% and boosts TPUs’ downward regulation capabilities by 32%.

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Section: Constraintsmentioning

confidence: 98%

Enhancing Renewable Energy Accommodation by Coupling Integration Optimization with Flexible Retrofitted Thermal Power Plant

Zou,

Xia,

Chi

et al. 2024

Applied Sciences

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“…The estimated mass flow rate of water needed to operate a hypothetical power plant with an aimed electric power capacity (P) is 49…”

Section: Governing Equationsmentioning

confidence: 99%

Subcritical and supercritical Rankine steam cycles, under elevated temperatures up to 900°C and absolute pressures up to 400 bara

Marzouk

2024

Advances in Mechanical Engineering

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The Rankine cycle is a conceptual arrangement of four processes as a closed vapor power thermodynamic cycle, where a working fluid (especially water as a liquid, as a vapor, and as a liquid-vapor mixture) can be used to convert heat into mechanical energy (shaft rotation). This cycle and its variants are widely used in electric power generation through utility-scale thermal power plants, such as coal-fired power plants and nuclear power plants. In the steam-based Rankine cycle, water should be pressurized and heated to be in the form of very hot high-pressure water vapor called “superheated steam,” before the useful process of expansion inside a steam turbine section occurs. If the absolute pressure and temperature of the superheated steam are both above the critical values for water (220.6 bara and 374.0°C), the cycle is classified as “supercritical.” Otherwise, the cycle is classified as “subcritical.” This study considers the impact of the temperature and pressure, independently, on the performance of a steam Rankine cycle. Starting from a representative condition for a subcritical cycle (600°C peak temperature and 50 bara peak absolute pressure), either the peak temperature or the peak absolute pressure of the cycle is increased with regular steps (up to 900°C, with a temperature step of 50°C, and up to 400 bara, with a pressure step of 50 bar). The variation of five scale-independent performance metrics is investigated in response to the elevated temperature and the elevated pressure. Thus, a total of 10 response curves are presented. When the temperature increased, all the five response variables were improved in a nearly linear profile. On the other hand, increasing the pressure did not give a monotonic linear improvement for each response variable. In particular, the cycle efficiency seemed to approach a limiting maximum value of 45% approximately, where further increases in the pressure cause diminishing improvements in the efficiency. When varying the peak pressure, an optimum minimum ratio of (water-mass-to-output-power) is found at 203 bara, although the cycle efficiency still increases beyond this value. In the present research work, the web-based tool for calculating steam properties by the British company Spirax Sarco Limited, and the software program mini-REFPROP by NIST (United States National Institute of Standards and Technology) were used for finding the necessary specific enthalpies (energy content) of water at different stages within the steam cycle. Both tools were found consistent with each other, as well as with the Python-based software package Cantera for simulating thermo-chemical-transport processes. The results showed that if the peak temperature reaches 900°C, a gain of about 5 percentage points (pp) in the thermal cycle efficiency becomes possible (compared to the case of having a base peak temperature of 600°C), as the predicted efficiency was found to increase from 38.60% (base case) to 43.67%. For the influence of the steam peak pressure, operating in the subcritical regime but close to the critical point appears to be a good choice given the gradual decline in efficiency gains at higher pressures. About 4.7 percentage point increase was found at the high subcritical peak pressure of 200 bara (compared to a base subcritical peak pressure of 50 bara). The results of this study also showed that the liquid water droplet mass fraction at the steam turbine exit diminishes from 11.00% at 600°C to only 1.48% at 900°C, which is favorable. This mass fraction grows from 11.00% at 50 bara to 27.89% at 400 bara, which is not acceptable. Every 100°C increase in the superheating temperature between 600°C and 900°C was found to cause aa increase in the cycle thermal efficiency by about 1.69 percentage points, and simultaneous a beneficial increase in the steam quality at the turbine exit by about 3.17 percentage points.

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“…Gürtürk and Oztop [11] reported an energy efficiency of 84.65% for the circulating fluidized bed boiler, suggesting that 84.65% of the input energy was efficiently converted into usable work. Kabeyi and Olanrewaju [12] and Khaleel et al [13,14] investigated the feasibility of export-based cogeneration by a large Kenyan sugar company and assessed the impact of operational parameters on power plant performance, respectively. Ciuła et al [15] sought to improve the energy balance of the landfill plant and optimize energy management from a renewable source.…”

Section: Introductionmentioning

confidence: 99%

Constant Steam Inlet Conditions and their Impact on the Thermal Efficiency of a Cogeneration Power Plant

Sumanraju,

Rao,

Sanke

2023

IJHT

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Cogeneration, a process facilitating the simultaneous production of electricity and useful heat from a singular energy source, has been investigated in this study. The primary objective of this research was to assess the performance dynamics of a cogeneration power plant under constant steam inlet conditions. Results revealed that the thermal efficiency (Ƞth) oscillated between 23.76% and 24.44%. The maximum thermal efficiency recorded was 24.44%, corresponding to an Energy Utilization Factor (EUF) of 0.85, under an inlet temperature of 502℃. Conversely, the lowest thermal efficiency measured was 23.76%, with an EUF of 0.72, observed at an inlet temperature of 503℃. These findings underscore the system's proficient energy utilization, notwithstanding minor fluctuations in steam parameters, such as inlet and various stages of operating conditions. A positive relationship was established between the heat-to-power ratio and the overall efficiency, which varied between 70.59% and 76.49% across different pressure values. The peak efficiency was noted at 84.7 kgf/cm 2 . Moreover, the EUF exhibited a range from 0.72 to 0.85, indicative of the system's energy use efficiency. A higher EUF value implies a more effective use of energy. At an EUF of 0.85, the cogeneration power plant demonstrated an impressive overall efficiency of 75.13%, signifying highly efficient energy conversion and utilization. However, at an EUF of 0.72, the overall efficiency declined to 70.59%, pointing to reduced efficiency in energy utilization. These results emphasize the critical role of maintaining a constant mass flow rate of steam and optimizing inlet parameters to enhance the efficiency of cogeneration power plants. Consequently, this study provides valuable insights into the operational optimization of cogeneration power plants.

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Developing an analytical model to predict the energy and exergy based performances of a coal-fired thermal power plant

Cited by 29 publications

References 23 publications

Enhancing Renewable Energy Accommodation by Coupling Integration Optimization with Flexible Retrofitted Thermal Power Plant

Enhancing Renewable Energy Accommodation by Coupling Integration Optimization with Flexible Retrofitted Thermal Power Plant

Subcritical and supercritical Rankine steam cycles, under elevated temperatures up to 900°C and absolute pressures up to 400 bara

Constant Steam Inlet Conditions and their Impact on the Thermal Efficiency of a Cogeneration Power Plant

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