Modeling and analysis of optimal performance of a coal-fired power plant based on exergy evaluation

Khaleel, Omar J.; Ibrahim, Thamir K.; Alnaimi, Firas Basim Ismail; Al-Sammarraie, Ahmed T.; Hassan, Saiful Hasmady Abu

doi:10.1016/j.egyr.2022.01.072

Cited by 20 publications

(6 citation statements)

References 38 publications

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“…As a result, the temperature differential between the cooling water and condensing steam widens. thus, this lead increases entropy generation and irreversibility, this finding line up with earlier research as [20]. The net power has decreased from 229.63 MW to 221.3 by 0.92 MW for every 0.02 bar increased, which is consistent with as [21,22], indicating that the condenser pressure has a considerable effect on the load produced.…”

Section: Resultssupporting

confidence: 86%

Evaluation Performance of the Steam Power Plant in Iraq Based on Energy and Exergy Analysis

Shaheed¹,

Mohammed²,

Radhi³

2023

IJHT

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Al-Mosyab thermal power station in Iraq is the subject of a case study to apply energy and exergy analysis in this presented paper. The methodical equations derived from mass, energy, and exergy balancing equations for each part of the cycle were computed using software Engineering Equation Solver (EES). The exergy analysis shows that the plant's second law efficiency and entire exergy destruction are 34.91% and 412.6 MW, respectively. The boiler experiences the most significant losses since they destroy the most exergy. The effect of the condenser pressure rise and the change in cooling water temperature on the performance of the thermal unit was studied. The thermal and exergy efficiency are reduced by 0.16% and 0.14%, respectively; the net power output decreased by 3.61%, demonstrating the significant impact of condenser pressure on the load produced. As a result of a rise in cooling water inlet temperature, the thermal and second law efficiency decrease by 1.196% and 1.203%, respectively, while the net power decreases by 0.57%.

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Section: Resultssupporting

confidence: 86%

Evaluation Performance of the Steam Power Plant in Iraq Based on Energy and Exergy Analysis

Shaheed¹,

Mohammed²,

Radhi³

2023

IJHT

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“…Optimizing some of these parameters or the components of a steam-based power plant through research studies helps in reducing the input heat energy needed, and thus in reducing the consumed fuel (in the case that fuel combustion is the method of generating the required heat energy for operating the steam cycle) for generating the same amount of electricity output. 23 The design parameters of a steam cycle include the temperature and pressure of the superheated steam (thus, the temperature and pressure of the steam as it exits a boiler and enters a steam turbine). The superheated steam temperature is here referred to as the ''superheating temperature.''…”

Section: Introductionmentioning

confidence: 99%

“…In another study, 26 the EES software was used to examine multiple effects of the turbine inlet temperature (TIT), the ambient temperature, and the condenser pressure for the unit 1 of Manjung coal-fired power in Malaysia. The turbine inlet temperature is the peak temperature of the superheated steam as it leaves the superheater.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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“…Combining the inlet flue gas temperature adjustment with the waste heat recovery of flue gas is the way to maximize the economic benefits [22]. At present, an effective way to utilize the waste heat of flue gas is to add a heating surface in the flue before the desulfurization system, and use the recovered waste heat to heat the feed water of the unit, preheat the cold air, dry the pulverized coal, or use it for cooling and heating [23].…”

Section: Introductionmentioning

confidence: 99%

An Efficient Method for Heat Recovery Process and燭emperature燨ptimization

Naser¹,

Dauwed²,

Alkhayyat³

et al. 2023

Computers, Materials &Amp; Continua

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Flue gas heat loss accounts for a significant component of the overall heat loss for coal-fired boilers in power plants. The flue gas absorbs more heat as the exhaust gas temperature rises, which reduces boiler efficiency and raises coal consumption. Additionally, if the exhaust gas temperature is too high, a lot of water must be used to cool the flue gas for the wet flue gas desulfurization system to function well, which has an impact on the power plant's ability to operate profitably. It is consequently vital to take steps to lower exhaust gas temperatures in order to increase boiler efficiency and decrease the amount of coal and water used. Desulfurization performance may be enhanced and water use can be decreased by reasonable flue gas characteristics at the entry. This study analyzed the unit's energy consumption, investment, and coal savings while proposing four coupling strategies for regulating flue gas temperature and waste heat recovery. A graded flue gas conditioning and waste heat recovery plan was presented under the condition of ensuring high desulfurization efficiency, along with the notion of minimizing energy loss owing to energy inflow temperature difference. Numerical results show that the proposed methods improved the system performance and reduced the water consumption and regulated the boiler temperature.

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Modeling and analysis of optimal performance of a coal-fired power plant based on exergy evaluation

Cited by 20 publications

References 38 publications

Evaluation Performance of the Steam Power Plant in Iraq Based on Energy and Exergy Analysis

Evaluation Performance of the Steam Power Plant in Iraq Based on Energy and Exergy Analysis

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

An Efficient Method for Heat Recovery Process and燭emperature燨ptimization

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