Impact of Inlet Fogging and Fuels on Power and Efficiency of Gas Turbine Plants

Abstract

A computational study to assess the performance of different gas turbine power plant configurations is presented in this paper. The work includes the effect of humidity, ambient inlet air temperature and types of fuels on gas turbine plant configurations with and without fogger unit. Investigation also covers economic analysis and effect of fuels on emissions. GT frames of various sizes/ratings are being used in gas turbine power plants in Saudi Arabia. 20 MWe GE 5271RA, 40 MWe GE-6561B and 70 MWe GE-6101FA frames are selected for the present study. Fogger units with maximum mass flow rate of 2 kg/s are considered for the present analysis. Reverse Osmosis unit of capacity 4 kg/s supplies required water to the fogger units. GT PRO software has been used for carrying out the analysis including; net plant output and net efficiency, break even electricity price and break even fuel LHV price etc., for a given location of Saudi Arabia. The relative humidity and temperature have been varied from 30 to 45 % and from 80 to 100° F, respectively. Fuels considered in the study are natural gas, diesel and heavy bunker oil. Simulated gas turbine plant output from GT PRO has been validated against an existing gas turbine plant output. It has been observed that the simulated plant output is less than the existing gas turbine plant output by 5%. Results show that variation of humidity does not affect the gas turbine performance appreciably for all types of fuels. For a decrease of inlet air temperature by 10 °F, net plant output and efficiency have been found to increase by 5 and 2 %, respectively for all fuels, for GT only situation. However, for GT with Fogger scenario, for a decrease of inlet air temperature by 10 °F, net plant output and efficiency have been found to further increase by 3.2 and 1.2 %, respectively for all fuels. For all GT frames with fogger, the net plant output and efficiency are relatively higher as compared to GT only case for all fuels. More specifically, net plant output and efficiency for natural gas are higher as compare to other fuels for all GT scenarios. For a given 70 MWe frame with and without fogger, break even fuel price and electricity price have been found to vary from 2.2 to 2.5 USD/MMBTU and from 0.020 to 0.0239 USD/kWh respectively. It has been noticed that turbines operating on natural gas emit less carbon relatively as compared to other fuels.

Keywords

Dates

  • Submission Date2011-07-08
  • Revision Date2012-10-15
  • Acceptance Date2012-12-03
  • Online Date2013-05-05

DOI Reference

10.2298/TSCI110708042B

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