Externally Fired Gas Turbine: Layout optimization for micro CHP generation with residual biomass firing

摘要

The Externally Fired Gas Turbine (EFGT) systems allows the use of unrefined fuels, such as biomass and waste in cogeneration arrangement for adequate efficiencies and high reliability, with respect to internal combustion systems based on gasification. The technology has some technological barriers related to thermal and mechanical resistance of the high temperature heat exchanger (HTHE), which is subject to fouling and corrosion phenomena of the parts exposed to flue gas and fly ash deposits. In this paper an investigation aimed to optimize a 100 kWel, Externally Fired micro Gas Turbine (EFmGT) for combined heat and power generation is presented and discussed. A techno-economic analysis was performed for different plant layouts which are energetically analysed for the case of complete external combustion and co-firing with natural gas, comparing power production, electrical and global efficiency. Each layout was studied by means of mass and energy balance. An economic analysis is also provided, focused on a comparison of initial investment, NPV and IRR. In the economic analysis the best feed in tariff for energetic valorisation of residual biomass was used to calculate the revenue of electric energy generated from biomass.