Thermal and Economic Analyses of Energy Saving by Enclosing Gas Turbine Combustor Section

摘要

An infrared (IR) thermography inspection indicated a high-temperature area (500~560°F) at the combustor section of the GE Frame 5 gas turbine of Dynegy Gas Processing Plant at Venice, Louisiana. To improve the thermal efficiency and reduce energy cost, thermal and economic analyses are conducted by enclosing the hot combustor section. This paper presents the methodology and procedure developed to calculate the thermal losses from the gas turbine combustor surface with and without the enclosure. Both natural convection and thermal radiation are considered. Iteration is employed to obtain the enclosure surface temperature. Sensitivities of the thermal losses to surface temperature, emissivity and radiation view factor are examined. It is found that the thermal losses from the combustor surface of the studied gas turbine are about 0.26 MMBtu/h (77.35 kW). The proposed enclosure can reduce the thermal loss to 0.029 MMBtu/h (8.5 kW). The saving is equivalent to about 0.17% in fuel saving. The return of investment is estimated to be one year. However, implementation of this proposed insulation enclosure requires approval from the turbine manufacturer.