Performance Analysis On Gas Engine – Gas Turbine Combined Cycle Integrated With Regenerative Gas Turbine

Abstract

The gas engine-gas turbine combined cycle was developed as the ETCS (Engine Turbo Compound System) that has a potential to be a future high performance combined cycle. The reciprocating engine operates with a maximum pressure and temperature in the cylinder, higher than that of the conventional gas turbines. When the gas engine is integrated with a gas turbine instead of a turbocharger, the concept of the ETCS with ERGT (Engine Reheat Gas Turbine) is available. In order to attain a better ETCS performance, a natural gas firing RGT (Regenerative Gas Turbine) was selected as the core gas turbine. For the system integration, the recuperator of RGT was exchanged for a gas engine. Focusing on the effect of engine exhaust temperature, we found that the ETCS cycle with ERGT has the potential to achieve a higher thermal efficiency than that of a re-generative cycle gas turbine with no change of TIT (Turbine Inlet Temperature). The engine exhaust temperature of 900°C increases the system power generation efficiency from 39% of RGT to 45% in ERGT (GT-Gas Engine) and up to 59% in ETCS (GT-Gas Engine-Steam Turbine) (TIT 1200°C).