Influence of the Syngas Feed on the Combustion Process and Performance of a Micro Gas Turbine with Steam Injection

Micro gas turbines (MGT) are promising devices for distributed cogeneration, offering a great opportunity for primary energy savings and reduction of pollutants and greenhouse gas emissions. The possible use of low-carbon fuels like syngas from biomass gasification, allows to further reduce the carbon footprint of distributed generation and to reduce the energy supply chain. In this work, the performance of a 100 kW MGT fed by natural gas and a biomass-derived synthesis gas have been assessed through a Matlab simulation algorithm, both in standard and steam injection configuration (STIG). An additional Matlab algorithm using Cantera's library has been created in order to study the combustion kinetics of the two fuels and to assess the turbine's emissions. Results show that for equal thermal power fed in the combustor, syngas combustion involves a reduction of NOx emissions of about by 75%, while CO emissions slightly increase with respect to natural gas combustion; in terms of performance, the use of syngas slightly reduces the power output and the efficiency of the machine. It was also found that the STIG configuration with the recovery of the heat content of the exhaust allows to inject up to 56 g/s of steam. A proper injection strategy is proposed and the electric power enhancement is evaluated in as much as 24%; also electric efficiency is slightly increased up to 29%. Moreover, steam injection in the combustion chamber, allows to dramatically reduced CO and NOx emissions. (C) 2017 The Authors. Published by Elsevier Ltd.