Dynamically Operated Fischer–Tropsch Synthesis in PtL—Part 2: Coping with Real PV Profiles

Abstract

Climate change calls for a paradigm shift in the primary energy generation that comes with new challenges to store and transport energy. A decentralization of energy conversion can only be implemented with novel methods in process engineering. In the second part of our work, we took a deeper look into the load flexibility of microstructured Fischer–Tropsch synthesis reactors to elucidate possible limits of dynamic operation. Real data from a 10 kW photovoltaic system is used to calculate a dynamic H2 feed flow, assuming that electrolysis is capable to react on power changes accordingly. The required CO flow for synthesis could either originate from a constantly operated biomass gasification or from a direct air capture that produces CO2; the latter is assumed to be dynamically converted into synthesis gas with additional hydrogen. Thus two cases exist, the input is constantly changing in syngas ratio or flow rate. These input data were used to perform challenging experiments with the pilot scale setup. Both cases were compared. While it appeared that a fluctuating flow rate is tolerable for constant product composition, a coupled temperature-conversion relationship model was developed. It allows keeping the conversion and product distribution constant despite highly dynamic feed flow conditions.

Options for demand side management in biofuel production: A systematic review

“…Loewert and Pfeifer 95 highlighted and evaluated a system for fluctuating feed gas and temperature in a pilot scale FT synthesis. In a subsequent work by Loewert et al 96 it was proven that highly load flexible operation in micro‐structured FT reactors in combination with a dynamic H 2 electrolyser with multi‐parameter changes in the 1‐min regime is feasible and fully controllable.…”

A Holistic Consideration of Megawatt Electrolysis as a Key Component of Sector Coupling

“…For dynamic synthesis operation, it was also shown via experiments on a relevant lab scale (H 2 feed equivalent to 500 W el electrolyzer load) that the ability of micro-structured reactors to cope with feed fluctuations does not influence the product quality, nor does it induce complete hydrogen consumption in the FT reactor, which could harm the catalyst due to the presence of the remaining CO. This is affected by the possibility of effectively controlling the reactor temperature [86].…”

Trendbericht Technische Chemie 2021

“…Loewert und Coautoren untersuchten den Betrieb solcher mikrostrukturierter FT-Reaktoren unter einem dynamischen Lastprofil vorgegeben durch die Einspeisedaten eines realen PV-Tischs. 47,48) Ihren Ergebnissen zufolge lässt sich mit dem eingesetzten Reaktorkonzept die FT-Synthese auch mit stark fluktuierenden Eingangsparametern effizient betreiben.…”