Hydrogen-rich gas as a fuel for the gas turbines: A pathway to lower CO2 emission

Hydrogen-rich fuel for the gas turbines can be considered as a transient way from hydrocarbon fuel to zero-carbon hydrogen fuel. In this paper, thermodynamic analysis of a combined cycle power plant (CCPP) fired with a hydrogen-rich fuel obtained via various ways is performed to understand the effect of a transient to this fuel on the CO2 emission as well as the efficiency of a power plant. Hydrogen-rich fuel with different content of hydrogen is analyzed. Two types of hydrogen-rich fuel are considered: fuel obtained via methane dilution with hydrogen (hydrogen from internal fuel supply infrastructure) - first case; fuel obtained via steam methane reforming (on-board hydrogen production technology) - second case. The first case showed that hydrogen addition to methane non-linearly leads to a decrease in CO2: hydrogen-rich fuel with 20% of H2 volume fraction gives a reduction in CO2 emission of 7.2%; 50% of H2 gives 23.5% reduction; 75% of H2 gives 51.1% reduction. The second case is considering hydrogen-rich fuel obtained via steam methane reforming using a renewable energy source. Hydrogen volume fraction up to 75% in hydrogen-rich fuel can be obtained after the reforming process. When 100% of methane is reformed, the reduction in CO2 emission up to 27% can be achieved. The minimum achievable level in CO2 emission is 75.17 gCO2/kW for an on-board hydrogen production technology via steam methane reforming which is corresponding to a hydrogen-rich fuel obtained via H2 dilution up to 53%.