Use of alternative fuels obtained from renewable sources in Brayton cycles

Analysis and simulation of the behaviour of gas turbines for power generation using different nonconventional
fuels obtained from different renewable sources are presented. Three biomass-tobiofuel
processes are considered: anaerobic digestion of biomass (biogas), biomass gasification
(synthesis gas) and alcoholic fermentation of biomass and dehydration (bioethanol), each of them
with two different biomass substrates (energy crops and municipal solid waste) as input.
The gas turbine behaviour in a Brayton cycle is simulated both in an isolated operation and in
combined cycle. The differences in gas turbine performance when fired with the considered biofuels
compared to natural gas are studied from different points of view related with the current complex
energetic context: energetic and exergetic efficiency of the simple/combined cycle and CO2
emissions. Two different tools have been used for the simulations, each one with a different
approach: while PATITUG (own software) analyses the behaviour of a generic gas turbine allowing a
total variability of parameters, GT-PRO (commercial software) is more rigid, albeit more precise in
the prediction of real gas turbine behaviour. Different potentially interesting configurations and its
thermodynamic parameters have been simulated in order to obtain the optimal range for all of them
and its variation for each fuel.