الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Simple and combined cycle gas turbines account for 50% of electricity generation in Egypt. Despite of their numerous advantages, they are nevertheless, negatively impacted by higher ambient temperatures. Therefore, the output of gas turbines falls to a value that is less than the rated power, in the meanwhile, the electricity demand is significantly increased during the summer season. Gas Turbine Inlet Air Cooling (GTIAC) can help to overcome this problem and improve the cycle performance. The present thesis is a 4E (Energy, Exergy, Economic, and Environmental) analysis applied to an integrated combined power station. The proposed system includes absorption-cooling system driven by flue gases integrated to conventional combined power plant. A unique analytical system of equations for the proposed overall cycle was developed. The overall performance was investigated based on the thermodynamic approach. The study was extended to include the economic and environmental aspects with respect to the data of Nubaria power plant, Egypt, which was chosen as a case study of the present work. The nominal capacity of the plant is 2250 MW as it comprises three identical generation modules. Each 750 MW module includes 2*250 MW gas turbine and 250 MW steam turbine. The introduced 4E study assured the feasibility of the proposed system to be used in gas or combined power plants. Performance improvement in the combined cycle is expected as a direct result of adding GTIAC system to the existing power plant. The results of the proposed integrated system indicated an average power augmentation for Nubaria power plant of 6.4 %. In addition, the annual power generation can be increased by 412.25 GWh /module. Exergy analysis was conducted to identify the areas of major energy losses. The processes associated with major energy degradation in the existing combined cycle have been clearly identified. The overall exergy destruction in the cycle is 360.5 MW, of which, 37.64 MW is the destruction of the exhaust flue gases. The maximum destruction (115.9 MW) takes place in the combustion chamber where huge amount of heat is created and added to the cycle. The minimum exergy destruction is the one of the HRSG (26.56 MW). The potential improvement in the exergy destruction can take place at the area just before the flue gases leave to the stack. This could be achieved by applying different waste heat recovery options. The overall cycle destruction has been increased after the integration with the proposed cooling system. This increase was due to additional exergy destruction brought to the system by the absorption cooling cycle. However, the maximum available power has been increased from 1110 to 1170 MW (at ISO condition). Despite of the mentioned increase in the integrated cycle’s exergy destruction, the cycle’s useful power has also increased from 750 to 791.4 MW. The parametric study shows that adjusting exhaust gases temperature to 122 oC will ensure the best operational scenario and stability of the integrated combined cycle. COP of the absorption-cooling machine will be higher than 0.8 at most cases due to relatively high evaporating temperatures. In addition, the cooling system will keep working for longer period even in relatively lower ambient temperatures. The estimated cooling capacity needed for each module (two gas turbines) is 4000 TOR approximately representing the minimum and optimum size at the same time. To increase the calculations margin of safety and achieve more smooth and reliable operations, the economic calculation was based on 6000 TOR for each module, which was recommended to be installed. In addition to the augmented power achieved by the implementation of inlet air-cooling, there are some other operation and maintenance benefits. For example; first, harvesting of the chilled water separated from the ambient air dehumidification. There is an opportunity to harvest an amount of 50 ton/hr. from Nubaria plant. It can be used in utility as cooling or make-up water supply with a potential annual saving of $100000 represents the eliminated cost of boilers’ feed water chemical treatment. Second, like all desert areas, the air filters in Nubaria plant used to suffer from the excessive fine dust that leads to the continuous formation of mud in the presence of high humidity at dawn times. Therefore, a surplus benefit of inlet air-cooling is increasing the lifetime of the filter elements of the air intake by preventing the formation of mud. This will lead to improving maintenance cost and saving time as well. Increasing the filter element lifetime will improve the plant availability with a potential annual saving of $250000. In more advanced stage, the analysis has extended to include the economic and environmental impacts of the proposed integration. The LCA (Life Cost Analysis) of the intended modification indicates a NPV (net present value) of MM$60 during lifetime of 20 years. The payback period is 3.5 years, based on an initial capital cost of MM$27, electricity sales price of $0.04/kWh, and fuel price of $4/MMBTU. Sensitivity analysis was conducted to predict the changes in both fuel and electricity prices. The plant estimated fuel demand was increased by 6.5% due to additional power generated. In the meantime, the specific fuel consumption has decreased from 164 g / kWh to 163.5 g / kWh (0.5 g/kWh). This decrease means an improvement of the combined cycle heat rate by 0.3%. The environment will benefit from a considerable reduction in CO2 emissions (30 Kilo-Ton/year) as one of the most important Green House Gases. Finally, the conducted analysis in this work has shown the necessity of GTIAC and indicated the positive impacts in all areas (Energy, Exergy, Economic, and Environmental) when applying it. The achieved results can provide certain reference for optimal design and economic operation of inlet air cooling system for electrical power generation enterprises in Egypt.