scholarly journals Thermal performance of a gas turbine based on an exergy analysis

2019 ◽  
Vol 128 ◽  
pp. 01027
Author(s):  
Abdallah Haouam ◽  
Chaima Derbal ◽  
Hocine Mzad

This work concerns the calculation and the analysis of the thermal performance of the components ofan MS 7001 type gas turbine with a nominal power of 87 MW using the concept of exergy. The exergy balance is used in addition to the energy balance to estimate the irreversibility of the air compressor, the combustion chamber and the turbine. The exergy analysis is carried out by applying the equilibrium equations obtained from the general definitions of the irreversibility of the thermodynamic processes and the data provided by the manufacturer. The results show that the exergy destruction of the gas turbine depends on the variation of the thermodynamic parameters: ambient temperature, compression ratio, air–fuel ratio. The combustion chamber has the highest exergy destruction estimated at 36.34 MW. The air compressor has an exergy efficiency of 84.19% that of the combustion chamber is 75.91% whilethat of the turbine expansion is 92.58%. The total exergy destruction of the gas turbine is 53.51 MW and itsefficiency is 32.44%. Improving the performance of the gas turbine requires decreasing the temperatureof the intake air.

2000 ◽  
Author(s):  
Zelong Liu ◽  
Hongguang Jin ◽  
Rumou Lin

Abstract Integrated Gasification Combined Cycle (IGCC) is considered as one of the advanced clean coal power technologies. Here, we have investigated an IGCC with air separation unit (ASU) on the basis of exergy analysis, and clarified the distribution of exergy destruction in sub-systems including air separation unit, coal gasifier, coal gas clean-up unit, air compressor, combustor of gas turbine, gas turbine, heat recovery steam generation and steam turbine. Particularly, we have focused on the interaction between the ASU and the gas turbine (GT). The results obtained disclosed the significant role of the integration between air separation unit and air compressor in the GT, and the effect of nitrogen injection to the combustor on IGCC overall performance. The study also points out that larger exergy destruction take place in the processes of gasification, combustion in GT, and air separation, and so does the change of exergy destruction distribution with the air integration degree and the nitrogen injection ratio. We have demonstrated the potential for improving the IGCC system. This investigation will be valuable for the synthesis of next-generation IGCC.


2015 ◽  
Vol 12 (3) ◽  
pp. 283-300 ◽  
Author(s):  
S.O. Oyedepo ◽  
R.O. Fagbenle ◽  
S.S. Adefila ◽  
Md. Mahbub Alam

In this study, exergoeconomic analysis and performance evaluation of selected gas turbine power plants in Nigeria were carried out. The study was conducted using operating data obtained from the power plants to determine the exergy efficiency, exergy destruction, unit cost of electricity and cost of exergy destruction of the major components of a gas turbine engine in the selected power plants. The results of exergy analysis confirmed that the combustion chamber is the most exergy destructive component compared to other cycle components as expected. The total efficiency defects and overall exergetic efficiency of the selected power plants vary from 38.64 to 69.33% and 15.66 to 30.72% respectively. The exergy analysis further shows that the exergy improvement potential of the selected plants varies from 54.04 MW to 159.88 MW. The component with the highest exergy improvement potential is the combustion chamber and its value varies from 30.21 MW to 88.86 MW. The results of exergoeconomic analysis show that the combustion chamber has the greatest cost of exergy destruction compared to other components. Increasing the gas turbine inlet temperature (GTIT), both the exergy destruction and the cost of exergy destruction of this component were found to decrease. The results of this study revealed that an increase in the GTIT of about 200 K can lead to a reduction of about 29% in the cost of exergy destruction. From exergy costing analysis, the unit cost of electricity produced in the selected power plants varies from cents 1.99 /kWh (N3.16 /kWh) to cents 5.65 /kWh (N8.98 /kWh).


Author(s):  
Lalatendu Pattanayak

In this study an exergy analysis of 88.71 MW 13D2 gas turbine (GT) topping cycle is carried out. Exergy analysis based on second law was applied to the gas cycle and individual components through a modeling approach. The analysis shows that the highest exergy destruction occurs in the combustion chamber (CC). In addition, the effects of the gas turbine load and performance variations with ambient temperature, compression ratio and turbine inlet temperature (TIT) are investigated to analyse the change in system behavior. The analysis shows that the gas turbine is significantly affected by the ambient temperature which leads to a decrease in power output. The results of the load variation of the gas turbine show that a reduction in gas turbine load results in a decrease in the exergy efficiency of the cycle as well as all the components. The compressor has the largest exergy efficiency of 92.84% compared to the other component of the GT and combustion chamber is the highest source of exergy destruction of 109.89 MW at 100 % load condition. With increase in ambient temperature both exergy destruction rate and exergy efficiency decreases.


Author(s):  
Awaludin Martin ◽  
Nur Indah Rivai ◽  
Rahmat Dian Amir ◽  
Nasruddin

In this study, exergoeconomic analysis was carry out on a 21.6MW gas turbine power plant by using logbooks record Pekanbaru Unit. The exergy analysis was start to determine the exergy destruction of each component of the power plant based on the first and second laws of thermodynamics and in this study, exergy and economic analysis were combined and used to evaluate the accrued cost caused by irreversibility, including the cost of investment in each component. The exergy analysis results showed that the location of the largest destruction was in the combustion chamber with 21,851.18 kW, followed by the compressor and gas turbine with 8,495.48 kW and 3,094.34 kW, respectively. The economic analysis resulted that the total cost loss due to exergy destruction was 2,793.14$/hour, consisting of compressor 1,066.43$/hour, combustion chamber 1,561.46$/hour and gas turbine 165.25$/hour. The thermal and exergetic efficiency of gas turbine power plant were 24.51% and 22.73% respectively.


Author(s):  
Nayyer Razmara ◽  
Rahim Khoshbakhti Saray

Exergy analysis provides useful information about the system optimization. An exergy analysis identifies the sources of thermodynamic inefficiencies by evaluating the exergy destruction within each system component. Splitting the exergy destruction into endogenous/exogenous parts represents a new development in the exergy analysis of energy conversion systems. The present work is an attempt to investigate the combustion process in a simple gas turbine and a cogeneration power plant based on the general concept of endogenous and exogenous exergy destruction. Therefore, using a graphical approach, the advanced exergy analysis is applied to both cycles with different fuels such as methane and diesel. Also, dual-fueling of combustion chamber is investigated based on the aforementioned approach in which 90% substitution of methane fuel for diesel one is considered. It is found that, in both cycles the combustion chamber has the largest value of the endogenous exergy destruction. The exergetic efficiency of combustion chamber increases when methane fuel is substituted for diesel fuel. Therefore, cycles efficiencies have been enhanced when fuel is substituted for diesel one. The results obtained here may provide some useful information for the optimal design and performance improvement of these cycles.


2017 ◽  
Vol 115 ◽  
pp. 977-985 ◽  
Author(s):  
Thamir K. Ibrahim ◽  
Firdaus Basrawi ◽  
Omar I. Awad ◽  
Ahmed N. Abdullah ◽  
G. Najafi ◽  
...  

Author(s):  
Maria Jonsson ◽  
Jinyue Yan

This paper is the second part of a two-part paper. The first part contains an introduction to the evaporative gas turbine (EvGT) cycle and the methods used in the study. The second part contains the results, discussion, and conclusions. In this study, exergy analysis of EvGT cycles with part flow humidification based on the industrial GTX100 and the aeroderivative Trent has been performed. In part flow EvGT cycles, only a fraction of the compressed air is passed through the humidification system. The paper presents and analyzes the exergetic efficiencies of the components of both gas turbine cycles. The highest cycle exergetic efficiencies were found for the full flow case for the GTX100 cycles and for the 20% part flow case for the Trent cycles. The largest exergy destruction occurs in the combustor, and the exergetic efficiency of this component has a large influence on the overall cycle performance. The exergy destruction of the heat recovery system is low.


1996 ◽  
Vol 118 (4) ◽  
pp. 782-791 ◽  
Author(s):  
Si-Doek Oh ◽  
Hyo-Sun Pang ◽  
Si-Moon Kim ◽  
Ho-Young Kwak

A general exergy balance equation that is applicable to any component of thermal systems has been formulated in this study. One of distinct features of this formulation is that the exergy involved in the component of any thermal system can be decomposed into exergy flows, entropy production flows, and the appropriate exergy rate terms such as fuel and available work. The exergy analysis based on this equation permits one to predict the thermal efficiency of the system, the exergy destruction in each component as well as the mass flow rate, the composition, and the temperature of the exhaust gases. We have examined the performance of a 1000 kW gas turbine cogeneration system when it is operated at part and full-load conditions through this analysis. We have also tested the effect of the inlet air temperature and the relative humidity of the inlet air on the performance of the system. The predicted values of the performances for the system have been compared with the actual performance data provided by the gas turbine manufacturer. It has been found that the measured data of net power and the properties of exhaust gases are in good agreement with calculation ones, differing by less than 3 percent. The exergy balance equation may be utilized in the exergoeconomic analysis to estimate the production costs depending on various input costs in a gas turbine cogeneration system.


Author(s):  
Soheil Fouladi ◽  
Hamid Saffari

In this paper, the thermodynamic modelling of a gas turbine power plant in Iran is performed. Also, a computer code has been developed based on Matlab software. Moreover, both exergy and exergoeconomic analysis of this power plant have been conducted. To have a good insight into this study, the effects of key parameters such as compressor pressure ratio, gas turbine inlet temperature (TIT), compressor and turbine isentropic efficiency on the total exergy destruction, total exergy efficiency as well as total cost of exergy destruction have been performed. The modelling results have been compared with an actual running power plant located in Yazd city, Iran. The results of developed code have shown reasonable agreement between the simulation code results and experimental data obtained from power plant. The exergy analysis revealed that the combustion chamber is the must exergy destructor in comparison with other components. Also, its exergy efficiency is less than other components. This is due to the high temperature difference between working fluid and burner temperature. In addition, it was found that by the increase of TIT, the exergy destruction of this component can be reduced. On the other hand, the cost of exergy destruction is high for the combustion chamber. The effects of design parameters on exergy efficiency have shown that increase in the air compressor ratio and TIT, increases the total exergy efficiency of the cycle. Furthermore, the results have revealed that by the increase of TIT by 350°C, the cost of exergy destruction is decreased about 22%. Therefore, TIT is the best option to improve the cycle losses. In addition, an optimization using a genetic algorithm has been conducted to find the optimal solution of the plant.


Author(s):  
Otujevwe P. Ogbe ◽  
Nnamdi B. Anosike ◽  
Ugochukwu C. Okonkwo

In this study, the probabilistic exergoeconomic analysis was performed for four industrial gas turbine (GT) units comprising of two   (GT16 and GT19) units of 100MW GE engine and two (GT8 and GT12) units of 25MW Hitachi engine at Transcorp Power Limited, Ughelli. These four industrial GT engine units were modelled and simulated using natural gas as fuel. The design point (DP) simulation results of the modelled GT engines were validated with the available DP thermodynamic data from original equipment manufacturer (OEM). This was done before the off-design point (ODP) simulation was carried out which represents the plant operations. The results obtained from exergy analysis at full load operation show that the turbine has the highest exergy efficiency followed by compressor and combustion having the least. For turbines these were 96.13% for GT8 unit, 98.02% for GT12 unit, 96.26% for GT16 unit, and 96.30% for GT19 unit. Moreover, the combustion chamber has the highest exergy destruction efficiency of 55.16% GT8 unit, 56.58% GT12 unit, 43.90% GT16 unit, and 43.30% GT19 unit respectively. The exergy analysis results obtained from the four units show that the combustion chamber (CC) is the most significant exergy destruction with lowest exergy efficiency and highest exergy destruction efficiency of plant components. The exergoeconomic analysis results from four units showed combustion chamber energy destruction cost of 531.08 $/h GT8 unit, 584.53 $/h GT12 unit, 2351.81$/h GT16, and 2315.93$/h GT19 unit. The probabilistic results analysis based on the input parameters distributions evaluated and discussed.


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