Comparative Energy and Exergy Analysis of a Thermal Power Plant with/without Retrofitted Inlet Air Cooler: A Case Study

Transcription

1 Comparative Energy and Exergy Analysis of a Thermal Power Plant with/without Retrofitted Inlet Air Cooler: A Case Study Sufianu A. Aliu, and Promise I. Ochornma Abstract The result of this study shows the performance of Ihovbor Gas Power Plant in Benin, Edo State Nigeria using first and second law of thermodynamics. Analysing the efficiency of the plant using first law of thermodynamics showed that with increase in inlet air temperature, the energy conversion efficiency of the plant reduces. The exergy efficiency of the plant also confirmed that increase in inlet air temperature results in decrease of the exergetic efficiency of the plant. Analysis of each of the components showed the greatest destruction of exergy was in the combustion chamber while the least is the Gas turbine section. Using numerical method in analyzing the gas turbine plant when retrofitting with an evaporative inlet air cooler showed better performance in energy conversion as power generation increased with an average of 1% per 1oC degree fall in temperature, the work ratio and thermal efficiency of the plant also increased. The analysis of the modified plant using second law of thermodynamics showed an increase in magnitude of both the exergy destroyed and the efficiency of the plant. Analysis showed that integrating evaporative cooler as component of the inlet air cooler increases the efficiency of the Air compressor by over 0.8% thus increasing the plant s exergetic efficiency. Index Terms Ambient Temperature; Efficiency; Energy; Evaporative Cooler; Exergy I. INTRODUCTION Benin is metropolitan city in Edo state Nigeria with an average temperature of 26.1 o C. A gas turbine power generation plant is located at Ihovbor a suburb of the city. Gas turbine plants are designed to operate optimally and more efficiently under International Organization for Standardization (ISO) specifications, but due to the atmospheric condition of the city, which is above ISO specification, the plant has not been operating at its optimal efficiency. Therefore, to increase the performance of gas turbine plants in high temperature climates, retrofitting an air cooler that will reduce the compressor inlet to or close to the design temperature before compression is necessary [1]. According to [2], since gas turbine is an air-breathing engine, its performance is changed by anything that affects the density and/or mass flow of the air intake to the compressor. The technologies developed to reduce inlet air temperature include evaporative inlet air cooler, mechanical Published on June 2, S. A. Aliu is with the Department of Mechanical Engineering, Faculty of Engineering, University of Benin, Benin City, Nigeria. ( sufianu.aliu@uniben.edu). P. I. Ochornma is with the Deeper Christian Life Ministry, Nigeria. ( ochornmapromise@gmail.com). chiller, refrigerant cycles. Evaporative cooler was selected because it is simpler and cheaper to operate and maintain [3]. The incorporation of an inlet air cooler to gas power plant reduces the compressor inlet temperature which results in reduction of turbine inlet temperature, thus increasing the turbine gross work output, the plant s efficiency and net power output. Evaporative cooler also increases the density of the inlet air which leads to increase in power output [4]. Systems and processes that degrade the quality of energy resources can only be identified and improved through a detailed analysis of the whole system [5]. Energy and exergy analysis are important and comprehensive tools that predict plants performance, efficiency of energy conversion and the extent of energy degradation under certain conditions. Energy is the ability to do work while exergy of a substance is a measure of its usefulness or quality. The energy content of a plant is the difference between energy input and output while exergy is the maximum quantity of work a system can do if their ambient properties are brought under a state of equilibrium with the environment. Exergy analysis makes it possible to characterize the optimal analysis technique on energy systems as well as to identify energy levels and thermodynamic adverse processes clearly in a system [6]. Exergy is based on the first and second laws of thermodynamics, and combines the principles of conservation of energy and non-conservation of entropy [7]. Exergy analysis is a useful method; to complement but not to replace energy analysis [8]. Reference [4] and [9] from their study of the behaviour of gas power plants showed that an inlet air temperature rise of 1 C reduces the power output by 1% while raising the heat rate of the gas turbine plant. Reference [10] from the analysis of Omotosho Power Plant Phase 1 using numerical methods showed that for ambient temperature in the range of o C that the overall efficiency of the plant decreased from 35-28% and that the incorporation of intake air cooling increases the power output of the plant by MW while [1] from modelling and simulation of an operational Rolls Royce, Industrial Olympus-SK 30 gas turbine plant located at Imiringi, Bayelsa State, Nigeria observed that the effect of incorporating evaporative cooling is that a drop in ambient temperature of 2.4 C leads to an increase of about 0.14% and 2.02kJ/kg in efficiency and network of the turbine respectively with an 0.002kg/kWh drop in specific fuel consumption. Reference [11] Demonstrated from their model of an H- 25MW Hitachi single shaft turbine plant with an inlet air cooler incorporating spray cooling technology using component-wise modelling and kotas exergy model that DOI: 1

2 when the inlet air was cooled the power output increases by 7% and efficiency by 2.7%. It also showed a reduction of 0.32% in total irreversibility rate (exergy destruction rate) for the cooled cycle and 0.39%, 0.29%, and 0.17% reduction of exergy destruction rate in the compressor, turbine and combustion chamber respectively. In their comparing the performance of Fogging and Steam Injection Gas Turbine (FSTIG) plant, and Steam Injection Gas Turbine (STIG) plant, [12] showed that the energy and exergy efficiencies, respectively, of the FSTIG plant are about 0.5% and 0.4% higher than those of the STIG plant. Reference [13] and [14] in their exergy analysis of power plant showed that the exergy destruction rate of the combustion chamber or boiler is higher than that of other components because combustion reactions are the most significant sources of exergy destruction and this large amount of exergy losses are traced to the high firing temperatures, incomplete combustion and possible mechanical losses in the combustion chamber. This paper seeks to investigate thermodynamic performance and advantage of incorporating an evaporative inlet air cooler to Ihovbor Gas Power Plant and compare its performance with the thermodynamic performance of the plant without an inlet air cooler using data generated from the plant. A. Gas Turbine A typical schematic diagram of an open gas power turbine where the properties of the working fluid is modified in the combustion chamber and is exhausted after doing work is shown in Fig. 1. Fig. 1. A practical gas turbine The air compressor is used to energize the working fluid by increasing its pressure through a pressure ratio (r p) by reducing its volume [15]. To be able to increase the pressure of the gas by reducing its velocity the moving and fixed blades are shaped as diffusers [16]. The increase in pressure of the inlet air allows the air to flow through the other components of the gas turbine. In order to achieve this an axial flow compressor is used. In the combustion chamber, the chemical properties of the fluid are changed and there is an increase of thermal energy due to the occurence of combustion as fuel is added [17]. Combustion is initiated by a spark plug while the fuel is introduced through a nozzle, and to maintain continuous flow a pilot recirculation zone is created in the main flow [18]. The flue gas leaving the combustion has temperature or enthalpy that can be utilized in driving a turbine. Mechanical power is extracted from the energized high temperature flue gas in the gas turbine section. The expansion of the gas takes place in more than one stage in an axial flow turbine. Energy extracted from the gas can be used to turn the shaft that drives an external load such as a propeller, fan or generator. The gas turbine used is mainly axial flow turbine [18]. B. Evaporative cooler Evaporative cooling makes use of heat transfer by convection to cool the temperature of the inlet air by evaporating demineralized water droplets. As its temperature is lowered, its relative humidity is increased. The gas turbine though a constant volume system; the evaporative inlet air cooler modifies the relative humidity, and pressure of the air, thus increasing the density and mass of the working fluid [19]. For an ideal evaporative inlet air cooler, the temperature of the air is cooled from its dry bulb temperature to its wet bulb temperature. Thus the evaporative inlet air cooler works as an adiabatic saturator that delivers air to the compressor with 100% relative humidity at lowered temperatures [20]. An example of evaporative cooling is high pressure fogging, where nozzle is used to split a high pressured water. As the air comes in contact with the water droplets, the air losses its sensible heat by evaporating the water droplets and a mist eliminator removes any water carryover, as condensation or carryover of water can exacerbate compressor fouling and degrade performance [2]. Fogging system is used as a method for cooling the air to the compressor by the direct injection of water, in order to reduce the ambient air temperature until it reaches the wet bulb temperature and thus increasing the net power [12], [21]. The major components of an evaporative are the centrifugal pump, mist eliminator, cooling media. The cooling performance of a typical fog system is around 80% 95%, and its effectiveness is limited by the difference between dry and wet bulb temperatures, which depend on the relative humidity at the plant location [21]. The cooling process by fogging is shown on a psychometric chart by drawing a constant enthalpy line in the direction of saturated air, like the adiabatic cooling process [12]. Referernce [22] has in their work shown the equations for determining the blowdown rate of an evaporative inlet air cooler. II. MATERIAL AND METHOD The data used for this study was obtained from available data log sheets of Ihovbor Gas Power Plant from Analysis of each of the plant components was carried out using the data obtained. The performance of each of the components of the plant was compared between the plant with retrofitted inlet air cooler and one without using equations written on Microsoft Excels. Shown in Fig. 2 is a schematic representation of a gas power plant retrofitted with an inlet air cooler. It consists of a spray cooler, compressor, combustion chamber and gas turbine. The unsaturated humid air passes through the spray cooler, where it becomes denser and cooler. To analyse the performance of the plant, the power output and other thermodynamic parameters of the plant is calculated using the equation of first law of thermodynamics, conservation of mass and equation of DOI: 2

3 state, while the exergy of the plant and its efficiency is calcuated using the second law of thermodynamics, conservation of mass and irreversibility generated due to the change in entropy of the system. The plant is analysed first using the data of the plant at point 1,2,3,4 as shown in Fig. 2 and values goten recorded. The performance of plant when cooled is analysed using calculated values gotten from using (1)-(4) for point 1, 2 assumming that the evaporative inlet air cooler only cools the tempearture of the inlet air while point 3 and 4 are same as the data used in analysing the plant when uncoled as their temperatures remain unaffected by the evaporative inlet air cooler. The pressure of the system whether cooled or uncooled is same at point 1-4 In an ideal situation the temperature after cooling T 1 will be the wet bulb temperature in Kelvin(K) but in a real operating situation T 1 depends on the evaporative cooler effectiveness while T a is the ambient temperature in Kelvin (K). Work done by the compressor is given by (5) Where W AC, m humid, C Phumid and h v denote Work done by by Air compressor in MW, mass of humid air (saturated air) in kg, specific heat capacity of the humid air at constant pressure and enthalpy of water vapour (steam) at given temperature respectively W AC = m humid (C phumid T 2 C phumid air T 1 ) + ω(h v2 h v1 ) (5) Since there is no water carry-over then ω(h v2 h v1 ) = 0. C phumid is given in (6) where C pa and C pv are specific heat capacity of the dry air and water vapour(steam) at constant presuure respectively. The algebraic formular proposed by [23] are used in (7) and (8) to get C pa and C pv respectively. Where t is the ambient temperature mesured in degree celcius ( o C). c phumid = c pa + ωc pv (6) The algebraic formular proposed by [25] are used to get C pa and C pv. c pair = (t + 30) 2 (7) c pv = ( t 100 Mass of humid air is given in (9) ) ( t 100 )2 (8) Fig. 2. A gas turbine retrofitted with inlet air cooler A. Energy Analysis The temperature of the air after cooling in the evaporative cooler is given as shown in (1) T 1 = T a (T a T wb )η evapo (1) where T, η denotes temperature and eficciency while 1, a, wb and evapo denote point 1, ambient air, wet bulb and evporative inlet air cooler respectively. 1, 2, 3 and 4 refers to point 1, 2, 3 and 4 respectively in the plant. The wet bulb temperature is gotten from psychometric chart. The relative humidity of the air after cooling is obtained from (2) where ω denote relative humidity, while h fg denote enthalpy of vapourazation in kj/kg and C pair specific heat capacity of air in kj/kgk. (ω 1 ω a )h fg = C pair (T a T 1 ) (2) After cooling, the cooled air is compressed in an air compressor (AC) to temperature T 2 and is gotten using (3) and (4). γ 1 T 2S = ( P 2 γ ) T 1 P 1 (3) T 2 = T 1 + T 2S T 1 η AC (4) m humid = m air (1 + ω) (9) During combustion fuel is combusted in the compressed air and heat is added to the system. Heat added in MW Q add is gotten using (10) where m g is the mass of flue gas (exhaust gas) and T is temperature Q add = m g (T 3 T 2 ) (10) The exhaust discharge temperature of the gas turbine is gotten from the (11) and (12) where P is pressure. γ 1 T 3 = ( P 3 γ ) T 4s P 4 (11) T 4 = T 3 η GT (T 3 T 4 ) (12) The work done by the turbine, W GT is gotten using (13) where C pg is the specific heat capacity of flue gas (exhaust gas). W GT = (m g ) (C pg T 3 C Pg T 4 ) + ω(h v3 h v4 ) (13) Since there is no carry-over ω(h v3 h v4 ) = 0. The performance of the plant is determined and analysed using (14) (18), where W net, η, SFC, HR WR are the power output, thermal efficiency, specific fuel consumption in kg of fuel per MWhr, heat rate in MJ/kWhr and work ratio of the plant respectively. m f and LHV, are the mass of fuel and the lower heating value of the fuel respectively. W net = W GT W AC (14) DOI: 3

4 η = W net m f LHV. (15) SFC = m f 3600 W net (16) HR = SFC LHV (17) WR = W net W GT (18) B. Exergy Analysis The exergy at different Points of the plant is gotten using T P (19) and (20), where E k and E k are the thermal and pressure exergy at any point respectively measured in MW. m, C p, T K, T ref, are the mass of working fluid at any point, specific heat capacity of the working fluid at any point within the plant, temperature of the working fluid at any point within the plant, and the ambient temperature respectively. The entropy at any point S K is goten using (21). E k T = mc P [(T k T ref ) T ref In T k T ref ] (19) E k P = mrt ref In P k P ref (20) S k = m[c p In T k T ref RIn P k P ref ] (21) The exergy of each component of the plant is gotten using (22) (24), where E T, E P, E D, are the Thermal exergy, pressure exergy, and Exergy destroyed in the component all measured in MW where o and i are the outlet and inlet point. The Chemical Exergy of a fossil fuel C ah b is determined using (25) which is a formular proposed by [24]. E T = (E o T E i T ) (22) E P = (E o P E i P ) (23) E D = T ref (S o S i ) (24) E CHE = m f ( b ) (25) a The total exergy of a plant is gotten using (26) where Q CC is the heat transfered from or to an external system and E W is the power output (work done) by the plant. E CHE + (E o T E i T ) + (E o P E i P ) + T ref (S o S i ) + Q CC + E W = 0 (26) The efficiencies of the system for the air compressor, combustion chamber, gas turbine and the overall plant are gotten using (27) (31) respectively. Where, ε AC, ε CC, ε GT, ε and ε D are the air compressor efficiency, combustion chamber efficiency, gas turbine efficiency, plant exergy efficiency and exergy destruction rate of the plant. E D,AC, E D,CC, E D,GT, E D,PLANT are the exergy destroyed in the air compressor, combustion chamber, gas turbine and the total exergy destroyed in the plant respectively, while E W,AC and E W,GT are the work done by the air compressor and the gas turbine respectively. ε AC = 1 E D,AC EW,AC (27) ε CC = 1 E D,CC ECHE (28) ε GT = 1 E D,GT EW,GT (29) ε = 1 E D,PLANT ECHE (30) ɛ D = E D,PLANT ECHE (31) The data in Table I are the average performance parameters of GT ONE based on ambient temperature. The average performance data of the plant based on inlet air temperature was gotten using Microsoft Excel sheet. The data represent the calculated performance of GT ONE. a TABLE I: ACTUAL PERFORMANCE DATA OF THE GAS TURBINE ONE AT DIFFERENT AMBIENT TEMPERATURE T 1 (K) T 2 (K) T 3 (K) T 4 (K) P 1 (10 5 Pa) P 2 (10 5 Pa) P 3 (10 5 Pa) P 4 (10 5 Pa) m f (kg/s) m a (kg/s) T f (K) Humidity % III. RESULTS AND DISCUSSION A. Results Shown in Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11 are the comparative power output, thermal efficiency, work ratio, heat rate, air compressor efficiency, combustion chamber efficiency, gas turbine efficiency, plant exergy efficiency and the exergy destruction rate of Unit One of Ihovbor Gas Power Plant with/without an inlet air cooler. Table II, Table IV and Table VI are the results of Unit Two, Unit Three and Unit Four of Ihovbor Gas Power Plant when uncooled while Table III, Table V and Table VII are the results of Unit Two, Unit Three and Unit Four of Ihovbor Gas Power Plant when cooled. The graphs represented below were drawn using Microsoft Excel. DOI: 4

5 WORK RATIO EFFICIENCY (%) THERMAL EFFICIENCY (%) EFFICIENCY (%) POWER OUTPUT [MW] HEAT RATE (MJ/kWhr) EJERS, European Journal of Engineering Research and Science Fig. 3. Power Output at Different Ambient Temperature Fig. 6. Heat Rate at Different Ambient Temperature 35 34, , , Fig. 4. Thermal Efficiency at Different Ambient Temperature Fig. 7. Air Compressor Efficiency at Different Ambient Temperature 0,488 0,486 0,484 0,482 0,48 0,478 0,476 0,474 0,472 0,47 0,468 Fig. 5. Work Ratio at Different Ambient Temperature 65 64,8 64,6 64,4 64, ,8 63,6 63,4 63,2 63 Fig. 8. Combustion Chamber Efficiency at Different Ambient Temperature DOI: 5

6 EFFICIENCY (%) EFFICIENCY % EFFICIENCY (%) EJERS, European Journal of Engineering Research and Science 99 98, , , , , , ,5 Fig. 9. Gas Turbine Efficiency at Different Ambient Temperature 38 UN Fig. 11. Plant Exergy Destruction Rate of the Gas Turbine at Different Ambient Temperature 61, , , ,5 UN Fig. 10. Plant Exergy Efficiency (%) of the Gas Turbine at Different Ambient Temperature TABLE II: RESULT OF COMPARATIVE ANALYSIS OF UN GAS TURBINE TWO UN Temp (K) WNET (MW) η WR HR (MJ/kWhr) ε AC ε CC ε GT ε ε D TABLE III: RESULT OF COMPARATIVE ANALYSIS OF GAS TURBINE TWO Temp (K) W NET (MW) η WR HR (MJ/kWhr) ε AC ε CC ε GT ε ε D DOI: 6

7 TABLE IV: RESULT OF COMPARATIVE ANALYSIS OF UN GAS TURBINE THREE UN Temp (K) W NET (MW) η WR HR (MJ/kWhr) ε AC ε CC ε GT ε ε D TABLE V: RESULT OF COMPARATIVE ANALYSIS OF GAS TURBINE THREE Temp (K) W NET (MW) η WR HR (MJ/kWhr) ε AC ε CC ε GT ε ε D Table VI: Result of Comparative Analysis of Uncooled Gas Turbine Four Temp (K) W NET (MW) η WR HR (MJ/kWhr) ε AC ε CC ε GT ε ε D TABLE VII: RESULT OF COMPARATIVE ANALYSIS OF GAS TURBINE FOUR Temp (K) W NET (MW η WR HR (MJ/kWhr) ε AC ε CC ε GT ε ε D B. Discussion Energy Analysis; The result of the comparative energy analysis of Ihovbor Gas power are shown and discussed in the Fig. 3, Fig. 4, Fig. 5, Fig. 6, Table II, Table III, Table IV, Table V, Table VI and Table VII From the Figs. and the Tables; the power output and the thermal efficiency of the GT decreased as the ambient temperature increases whether it was cooled or uncooled [10]. The power output of the plant did not reach the plant specification 126MW because it is based on ISO specification of 288K. For each of the temperature, it was discovered that incorporating an inlet air cooler will increase the power output of the gas turbine by 4.30 MW which 4.22% increase on the average for GT 1, 4.11 MW, 2.52MW, and 4.30 MW which is 4.07%, 2.49% and 4.11% increase for GT2, GT3 and GT4 respectively [10],[11] and almost equivalent to one percentage (1%) increase per degree fall in temperature as reported by [4], [9]. The increase in power output is due to the increase in the mass DOI: 7

8 flow rate of the working fluid (Humid air) and the increase work ratio of the gas turbine by 1.02%, 1.56%, 1.52% and 1.70% for GT1, GT2, GT3 and GT4 respectively on the average in the cooled gas turbine as the increase in magnitude of work done by the compressor is less when compared to the increased gross work output. Despite the increase in magnitude of fuel consumption necessitated by the decrease in working fluid Turbine inlet temperature and the mass of the humid air, the thermal efficiency of the plant increased when the inlet is cooled by 0.74%, 1.25%, 2.42%, 4.26% for GT1, GT2, GT3 and GT4 respectively on the average and this gave a decrease in Heat Rate of the power plant when cooled by 77.56kJ/kWhr, kJ/kWhr, kJ/kWhr, kJ/kWhr for GT1, GT2, GT3 and GT4 respectively on the average showing that fuel is more efficiently utilized as the inlet temperature decreases [1], [4], [9]. Exergy Analysis; The result of the comparative energy analysis of Ihovbor Gas power are shown and discussed in the Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig.11, Table II, Table III, Table IV, Table V, Table VI and Table VII From the Figs. and the Tables, the combustion chamber had the lowest efficiency and this is due to high temperature of the combustion/heat addition process [13], [14]. By incorporating an inlet air cooler, the exergy destroyed in the air compressor decreased thus increasing its efficiency increase by 1.09%, 0.80%, 0.81% and 0.86% for GT1, GT2, GT3 and GT4 respectively [11], [12]. This improvement in performance is due to the decrease in inlet air temperature while for the combustion chamber, exergy destroyed increased and this is due to the increase in mass flow rate of fuel. For the Gas Turbine the exergy destroyed also increased this increase is due to increase in flue gas flow rate, while its exergy efficiency remained the same because the Turbine inlet and outlet temperature are the same either cooled or uncooled. In general, the incorporation of an inlet air cooler will increase the exergy efficiency of the plant by 1.11%, 0.13%, 0.48% and 0.80% for GT1, GT2, GT3 and GT4 respectively while reducing its exergy destruction rate and this agrees with [11], [12], [13]. This showed that the increase in exergy destroyed is less in ratio to the increase in useful exergy of the system as a result of the incorporation of Inlet air cooler. IV. CONCLUSION The comparative energy and exergy analysis of Ihovbor Gas Power Plant with/without a retrofitted inlet air cooler was carried out. The result of the study showed the plant didint reach its specified power output 126.1MW because of its ambient conditions and that the incorporation of evaporative inlet air cooler will increase the power generation of the plant and that every 1K decrease in temperature of inlet air temperature leads to above 1% increase in power generation. The increase in efficiency of the plant as temperature decreses both for the cooled and uncooled plant shows that average ambient temperatue of the operating site of the plant is a factor in determing the expected performance of the plant. The incorporation of evaporative inlet air cooler increased the efficiency by 0.74%, 1.25%, 2.42%, and 4.26% for GT1, GT2, GT3 and GT4 respectively on the average and this gives a decrease in Heat Rate of the power plant when cooled by 77.56kJ/kWhr, kJ/kWhr, and kJ/kWhr, kJ/kWhr for GT1, GT2, GT3 and GT4. The exergy analysis of the plant demonstrated that the incorporation of inlet air cooler leads to increase in magnitude of exergy destroyed necessitated by the increase in mass of air and mass of fuel consumed by the plant. The seeming disadvantage of incorporating evaporative inlet air cooler is the increase in exergy destroyed as result of increase in mass of working fluid (Air and Fuel). Despite the increase in magnitude of exergy destruction, the plant performed better as the efficiency of the plant increased by 1.11%, 0.13%, 0.48% and 0.80% for GT1, GT2, GT3 and GT4 respectively while reducing its exergy destruction ratio. ACKNOWLEDGMENT The authors appreciate the staff of Niger Delta Power Holding Company (NDPHC): Benin Generating Station, Ihovbor, Edo State, Nigeria led by the Plant Manager; Engr. Peter Okougbo for providing the data and technical information used for this research work. REFERENCES [1] R. Poku, E.A. Ogbonnaya, Effects of Evaporative Cooling on the Performance of a Gas Turbine Plant Operating in Bayelsa State, Nigeria, International Journal of Engineering and Technology Volume 4 No. 8, pp , August [2] F.J Brooks, GE Gas Turbine Performance Characteristics, GE Power systems, New York, 2010, pp [3] A. P. Santos, C. R. Andrade, Analysis of Gas Turbine Performance with Inlet Air Cooling Techniques Applied to Brazilian Sites, J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 3, pp , Jul-Sep 2012 [4] T. K Ibrahim, M.M Rahman, A. N. Abdalla, Improvement of gas turbine performance based on inlet air cooling systems: A Technical Review, International journal of physical sciences, Vol 6 No 4, pp , Feb [5] B.T. Lebele-Alawa, J.M. Asuo, Exergy Analysis of Kolocreek Gas- Turbine Plant, Canadian Journal on Mechanical Sciences & Engineering Vol. 2 No. 8, pp , Dec [6] A. Mousafarash, M. Ameri, Exergy and exergo-economic based analysis of a gas turbine power generation system, Journal of Power Technologies Vol 93, pp , Jan [7] S.O. Oyedepo, R. O. Fagbenle, S. S. Adefila, and M. M. Alam, Exergy costing analysis and performance evaluation of selected gas turbine power plants, Cogent Engineering, Vol 2 No 1, pp Nov [8] A. Bejan, Fundamentals of Exergy Analysis, Entropy Generation Minimization, and the Generation of Flow Architecture, International Journal of Energy Research, Vol. 26, No. 7, pp June [9] H. Kim, H. Ko and H. Perez-Blanco, Exergy analysis of gas-turbine systems with high fogging compression, International Journal of Exergy, Vol 8 Issue 1, pp. 6 32, Jan [10] H.O. and Egware, A.I. Obanor, Exergy Analysis of Omotosho Phase I Gas Thermal Power Plant International Journal of Energy and Power Engineering, Vol. 2 No. 5 pp , Nov [11] F.A. Abam, I. U. Ugot., and D. I. Igbong, Performance Analysis and Components Irreversiblities of a (25 MW) Gas Turbine Power Plant Modeled with a Spray Cooler, American Journal of Engineering and Applied Sciences Vol 5, pp , Feb [12] H. Athari, S. Soltani, M. Rosen, S. Mahmoudi, and T. Morosuk, Comparative Exergoeconomic Analyses of Gas Turbine Steam Injection Cycles with and without Fogging Inlet Cooling, Sustainability, Vol 7 pp , Sept [13] M. Ameri, P. Ahmadi, and A. Hamidi, Energy, Exergy and Exergoeconomic Analysis of a Steam Power Plant: A case study, DOI: 8

9 International Journal of Energy Resarch, Vol. 33 pp , April [14] O. O. Ighodaro, B. A. Aburime, Exergetic Appraisal of Delta IV Power Station, Ughelli, Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) Volume 2, Issue 2 pp April [15] H.A. Arangi, P. Sivaram and H.N. Babu, Analysis of Inlet Air Temperature Effect on Gas Turbine Compressor Perfornance, International Research Journal of Engineering and Technology Volume: 2 Issue: 8 pp Nov [16] R.H. Perry, D.W. Green, Perry s Chemical Engineering Handbook 8th Edition McGraw-Hill, New York 1997 ch 10, pp [17] Y.A. Cengel, M.A. Boles, Thermodynamics: An Engineering Approach 7th Edition; Mcgraw Hill, New York 2011 ch 15, pp [18] H. Saravanamuttoo, H. Cohen, G.F.C. Roger, Gas Turbine Theory, 5 th edition, Pearson Education Ltd, England 1996 ch 6 pp [19] M.A. Ehyaei, A. Mozafari, M.H. Alibiglou, Exergy, economic & environmental (3E) analysis of inlet fogging for gas turbine power plant, Energy Vol. 36, Issue 12, pp , Dec [20] R. Ranu, K. Arif, Analysis of Effects of Evaporative Inlet Cooling on Gas Turbines", International Journal of Engineering Trends and Technology (IJETT), Vol 37, No. 2, pp July [21] K.Y. AL-Salman, Q.A. Rishack, S.J. AL-Mousawi, Parametric Study of Gas Turbine Cycle with Fogging System, J.Basrah Researches (Sciences) Vol. 33, No.4, pp , Dec [22] M. Ali, H. Abdalla, Thermo-Economic Analysis of inlet Air Cooling in Gas Turbine Plants, Journal of Power Technologies Vol 93, No. 2, pp , [23] M. Musa, Novel evaporative cooling systems for building applications, PhD thesis, The School of the Built Environment, The University of Nottingham, 2009 [24] A. Vosough, A. Noghrehabadi, M. Ghalambaz and S. Vosough, Exergy Concept and its Characteristic, International Journal of Multidisciplinary Sciences and Engineering, Vol. 2, No. 4, pp July [25] P.I. Ochornma, Comparative Energy and Exergy Analysis of Ihovbor Gas Power Plant With/Without Retrofitted Inlet Air Cooler, M.Eng Project; Department of Mechanical Engineering, University of Benin, Edo State, 2017 Sufianu A. Aliu was born in Kano, Nigeria on the 17th of February He is a native of Adavi-Eba, Adavi L.G.A., Kogi State, Nigeria. He obtained Bachelor of Engineering in Mechanical Engineering, University of Ilorin, Ilorin, Nigeria, (1998), Masters of Science in Mechanical Engineering, University of Ibadan, Ibadan, Nigeria, (2003) and PhD in Mechanical Engineering, University of Ibadan, (2014). He is a lecturer in the Department of Mechanical Engineering, Faculty of Engineering, University of Benin, Benin City, Edo State, Nigeria. His area of specialization is thermal-fluid engineering. Dr. Aliu is a corporate member of the Nigeria Society of Engineers and a registered Engineer with the Council for the Regulation of Engineering in Nigeria. engineering. Promise I. Ochornma was born on 17 May, 1990 in Asaba, Delta State, hails from Ase-Imonite, Ogba/Egbema/Ndoni LGA, Rivers State Nigeria. He obtained Bachelor of Engineering in Mechanical Engineering, Anambra State University, Nigeria, (2014), Masters of Engineering in Mechanical Engineering (Thermal Power Option), University of Benin, Benin City, Edo State Nigeria, (2017) He is an engineer with the Deeper Christian Life Ministry. His areas of specialization is thermal-fluid DOI: 9