College of Engineering

A master thesis was discussed in Department of Mechanical Engineering / College of Engineering at University of Mosul entitled “Energy and Exergy Analysis of combined Gas Turbine generator” submitted by (Rafal Khalid Jasim Alswediani), Supervised By Assist. Prof. Dr. Abdul Rahman Habo Mohammed Habo on Wednesday, March 30, 2022.The current research involve a theoretical study to evaluate the thermal performance of a combined gas turbine through the 1st and 2st law of thermodynamics. Which included several parts and different operating parameters. In the first part, the effect of temperature increase on the performance of the simple gas turbine unit was examined under different operating parameter. The obtained results show that as the atmospheric temperature increase from10 0C to 50 0C, the power out, thermal efficiency and mass flow rate of air would decreased which is demonstrate in chapter 4.The gathered results show a significant effect of steam pressure on the performance of HRSG and particularly when the steam pressure changed from 50bar to 85 bar, the amount of heat gained would be decrease nearly by 6.4%. However the low steam pressure increase from 2 bar to 8 bar, then the heat gained in HRSG and the mass flow rate will be decrease nearly by 5.9% and 26.98% respectively which the flow rate of working fluid for higher pressure HRSG would not change. The performance of combined gas turbine unit is carried out under different operating parameter when the atmospheric temperature increase from 10 0C to 50 0C. The results show that the power output will increase nearly by 29.31% when the unit operate at 10 0C and pressure ratio 12 in comparison to the simple gas turbine unit. Moreover the thermal efficiency is increased to be 42.29%, this means that thermal efficiency increased by 22.53% in comparison to simple gas turbine unit. While the S.F.C is found to be 28.5% less than the simple unit .Also results show that the combined unit thermal efficiency will be decrease nearly by 2.66% when the pinch point increase from 10 0C to 40 0C. However, to assess the exergy destruction, the 2st law of thermodynamics has been introduced in order to find the higher amount of exergy destruction for combined gas turbine components including simple unit, heat recovery steam generator, steam turbine and finally the whole unit. Result show that the maximum destruction take place in the combustion chamber which is found nearly by (228.9MW), while the exergy destruction in HRSG is found to be (138.9 MW), the steam turbine unit was also affected by the increase in the external ambient temperature and the highest value of the exergy destruction analysis is (5.654 MW) at the ambient temperature is 50 0C and the highest amount of exergy destruction in a combined gas turbine unit is (496.356 MW) at an ambient temperature of 10 0C.