Generation of renewable hydrogen from sewage sludge — Quantitative and energy-based technology evaluation.

The paper presents a critical analysis of a commercial pre-feasibility study for hydrogen generation from sewage sludge generated in a wastewater treatment plant sized Population Equivalent (PE) = 160,000 Three commercial offers based on hydrothermal carbonization, gasification/plasma gasification and gas separation, are analysed and validated in terms of chemical reactions and energy balance. The obtained hydrogen yield equals 10 kg H 2 /Mg sludge for Technology#2 and 5.5 kg H 2 /Mg sludge for Technology#3, while the process efficiency equals 31.4% and 41.2%, respectively. The offer for Technology#1 is inconsistent. The potential market can be built in the transport sector, based on buses (8–12/day) or locomotives (1–2/day) and complemented by passenger cars (16–22/day). Hydrogen surplus can be disposed into the natural gas network at a city gate station, with target concentration <2%. Alternatively, it is possible to install a fuel cell unit for on-site electricity generation of 1780 MWh/a sold to the public grid. • Commercial technologies of hydrogen production from sewage sludge were studied. • Technologies of hydrothermal carbonization and plasma gasification were validated. • 1 of 3 commercial offers was found inconsistent regarding thermodynamics. • Hydrogen yield was found 5.5–10 kg/Mg sludge. • Process energy efficiency was found 31.4%–41.2%. [ABSTRACT FROM AUTHOR]