Power and Hydrogen Co-Production in Flexible “Powdrogen” Plants

Abstract

This study investigates the potential of “Powdrogen” plants for blue hydrogen and decarbonized electric power production, conceived to operate flexibly depending on the electricity price and to increase the capacity factor of the hydrogen production and CO2 separation units. The hydrogen production is based on fired tubular reforming or autothermal reforming technologies with precombustion CO2 capture by a methyl diethanolamine (MDEA) process. The power island is based on a combined cycle with an H2-fired gas turbine and a triple pressure reheat heat recovery steam generator (HRSG). The analysis considers three main plant operating modes: hydrogen mode (reformer at full load with hydrogen export and combined cycle off) and power mode (reformer at full load with all hydrogen burned in the combined cycle), plus an intermediate polygeneration mode, producing both hydrogen and electricity. The possibility of integrating the HRSG and the reformer heat recovery process to feed a single steam turbine has been explored to allow keeping the steam turbine hot also in hydrogen operating mode. The economic analysis investigates the competitivity of the plant for different operating hours in hydrogen and power modes. Results suggest that these plants are likely to be a viable way to produce flexibly low-carbon hydrogen and electricity following the market demand.