Ultra-low emission flexible plants for blue hydrogen and power production, with electrically assisted reformers

Abstract

This study investigates the potential of natural gas-based plants designed to produce blue hydrogen and decarbonized electric power, conceived to operate flexibly depending on the electricity price. This paper considers plants based on fired-tubular reforming (FTR) and auto-thermal reforming (ATR) technologies, with MDEA-based pre-combustion CO2 capture process and partial electrification of the reformer, designed to achieve CO2 capture efficiency higher than 95 %. Heat and mass balances for the chemical and power island are evaluated at both full and part load to define the corresponding operating maps. With pre-combustion CO2 capture only, FTR plants can achieve CO2 capture rates higher than 90 %, H2 production efficiency of 73–74 % and power generation efficiency of around 47 %. Reformer electrification allows increasing overall capture efficiency to 95 %. Plants based on ATR can approach 95 % capture efficiency without electrification and achieve H2 efficiency similar to FTR but higher electric efficiency, close to 51 %. An economic analysis is performed to assess profitability of the plants under electricity price scenarios with different penetration of renewables. The economic analysis shows that flexible plants may be profitable in future scenarios with high penetration of renewables and high price variance, resulting in IRR around 10–17 % for hydrogen selling prices of 2.0–2.5 €/kg, natural gas price of 9 €/GJ and carbon tax of 100 €/tCO2.