Integrating a gas turbine system and a flameless boiler to make steam for hydrogen production in a solid oxide steam electrolyzer

Solid oxide steam electrolyzer (SOSE) uses both electricity and steam to produce hydrogen in a large scale. Considering losses in the electrical power transmission and significant amounts of fuel for steam making, it is affordable to integrate the gas turbine (GT) system to the SOSE in the power plant to generate hybrid electrical power-hydrogen fuel. In this paper, design and performance of a hybrid electrical power generation-hydrogen production system are analytically analyzed. To make steam, a flameless boiler is coupled to the GT system using the GT extremely hot exhaust gases as the oxidizer. The results revealed that the turbine inlet temperature (TIT) should be kept more than 1314 K to obtain GT exhaust gases at temperatures higher than 870 K (auto-ignition temperature of methane) to maintain flameless combustion mode in the boiler. By increasing the flameless boiler temperature and consequently enhancing the SOSE steam temperature from 950 K to 1350 K, the rate of overall fuel consumption in the flameless boiler slightly increases, however the hydrogen production rate escalates from 2.2 mol/s to 10.2 mol/s. The novelty of this paper lies on the using the GT exhaust gases enthalpy to run a flameless boiler to drastically mitigate fuel consumption in hydrogen production system. The presented model in this paper can be used to perform more thermochemical analyses to attain insightful understanding of the hybrid electrical power-hydrogen production systems. © 2020 Elsevier Lt