Comparative Performance Assessment of CRGT Power Plants Fuelled by Hydrogen Energy Carriers

Chemically Recuperated Gas Turbines (CRGT) perform the exhaust heat recovery through the endothermic steam reforming process of the primary fuel, which produces an H₂-rich fuel. In particular, methanol, ethanol and DME are very suitable fuels for CRGT power plants owing to their low reforming temperature, which leads to a very effective waste heat recovery, especially in comparison with CRGT solutions fuelled by natural gas. This paper reports a comparative performance analysis of CRGT power plants fuelled by methanol, ethanol and DME. The performance analysis has been carried out with reference of two 40 MW class commercial turbines (the aeroderivative GE LM6000 unit and the heavy-duty GE PG6561 one). The best operating conditions have been pointed out by considering different operating parameters for the reforming process (pressure, temperature and water/fuel molar ratio). Thermochemical recuperation in CRGT power plants allows to achieve a significant performance improvement in comparison with the performance of the reference gas turbines without any exhaust heat recovery. In particular, the CRGT solutions here considered show maximum efficiencies in the range 54–57%, according to the primary fuel considered, with a corresponding increase of the power output and a decrease of the specific CO₂ emissions.