TY - THES

T1 - Oxygen provision for a steel mill via flexible electrolyser operation

AU - Wallner, Stefan

N1 - no embargo

PY - 2022

Y1 - 2022

N2 - Due to the lower energy consumption and carbon dioxide emissions, steel production via electric arc furnaces represents a promising alternative to integrated steel production via blast furnace and basic oxygen furnace. Nevertheless, steelmaking through the electric arc furnace route consumes high amounts of electric energy, natural gas and oxygen. This thesis deals with feasible ways to provide carbon dioxide neutral oxygen while also cutting back on natural gas demands via the implementation of a power-to-gas plant. Hydrogen produced by electrolysis could be used to substitute natural gas, either directly by combusting hydrogen or by creating synthetic natural gas via methanation, whereas by-product oxygen could be utilized in the steelmaking process. Moreover, electrolysis would provide a flexibility option, enabling better integration of intermittent energies into the electricity grid and the optimal exploitation of varying electricity prices. Using an energy system model of a steel mill, different scenarios for the application of electrolysis and subsequent methanation are studied. Then, the flexibility and the economic feasibility of these scenarios are assessed. It turns out that economic performance mainly depends on the utilization of hydrogen. Using technical parameters and prices from 2020, only scenarios focusing on selling hydrogen are profitable, while scenarios focusing on substituting natural gas are not viable under the specified conditions.

AB - Due to the lower energy consumption and carbon dioxide emissions, steel production via electric arc furnaces represents a promising alternative to integrated steel production via blast furnace and basic oxygen furnace. Nevertheless, steelmaking through the electric arc furnace route consumes high amounts of electric energy, natural gas and oxygen. This thesis deals with feasible ways to provide carbon dioxide neutral oxygen while also cutting back on natural gas demands via the implementation of a power-to-gas plant. Hydrogen produced by electrolysis could be used to substitute natural gas, either directly by combusting hydrogen or by creating synthetic natural gas via methanation, whereas by-product oxygen could be utilized in the steelmaking process. Moreover, electrolysis would provide a flexibility option, enabling better integration of intermittent energies into the electricity grid and the optimal exploitation of varying electricity prices. Using an energy system model of a steel mill, different scenarios for the application of electrolysis and subsequent methanation are studied. Then, the flexibility and the economic feasibility of these scenarios are assessed. It turns out that economic performance mainly depends on the utilization of hydrogen. Using technical parameters and prices from 2020, only scenarios focusing on selling hydrogen are profitable, while scenarios focusing on substituting natural gas are not viable under the specified conditions.

KW - demand side management

KW - elctric steel mill

KW - power-to-gas

KW - PEM-electrolysis

KW - flexible oxygen production

KW - energy system modelling

KW - energy system optimization

KW - Demand Side Management

KW - Elektro-Stahlwerk

KW - Power-to-Gas

KW - PEM-Elektrolyse

KW - flexible Sauerstoffproduktion

KW - Energiesystem Modellierung

KW - Energiesystem Optimierung

M3 - Master's Thesis

ER -