Comparative analysis of the efficiency of using hydrogen and steam methane reforming storage at combined cycle gas turbine for cogeneration

Abstract

Combined cycle gas turbine cogeneration power plants provide maximal thermal efficiency. The facility thermal load depends upon ambient conditions and it may limit its unloading degree, or control range. Energy accumulation extends the control range by the energy storing during the power excess period and the energy discharge during the high consumption period. This paper considers two accumulation technologies, with the steam methane reforming and with hydrogen storage by using electrolyzer and fuel cell. In steam methane reforming technology a part of heat recovery steam generator steam passes to the synthetic gas production and reduces the electric power production during the low load periods. During the peak load periods, the synthetic gas is burned in combined cycle gas turbine and peak load gas turbine combustors. In hydrogen accumulation technology the excessive power produces hydrogen in an electrolyzer, which is stored and used during the peak load periods in fuel cells for additional electricity production. The simulation was carried out in the Aspen Plus software, the thermo-physical fluid properties were determined using the Peng-Robinson state equation. Application of the steam methane reforming accumulation technology increases the facility contribution margin by 2.6%, the hydrogen accumulation technology reduces this margin by 0.1%.