Integration of Renewable Hydrogen Production in Steelworks Off-Gases for the Synthesis of Methanol and Methane

Abstract

The steel industry is among the highest carbon-emitting industrial sectors. Since the steel production process is already exhaustively optimized, alternative routes are sought in order to increase carbon efficiency and reduce these emissions. During steel production, three main carbon-containing off-gases are generated: blast furnace gas, coke oven gas and basic oxygen furnace gas. In the present work, the addition of renewable hydrogen by electrolysis to those steelworks off-gases is studied for the production of methane and methanol. Different case scenarios are investigated using AspenPlusTM flowsheet simulations, which differ on the end-product, the feedstock flowrates and on the production of power. Each case study is evaluated in terms of hydrogen and electrolysis requirements, carbon conversion, hydrogen consumption, and product yields. The findings of this study showed that the electrolysis requirements surpass the energy content of the steelwork’s feedstock. However, for the methanol synthesis cases, substantial improvements can be achieved if recycling a significant amount of the residual hydrogen.

Economic Evaluation of Renewable Hydrogen Integration into Steelworks for the Production of Methanol and Methane

“…Those off-gases have several uses within the plant, mostly for heating and electricity production. It is assumed that approximately 50% of the total generated amounts are available for the synthesis of methanol and methane, after the rest is utilized in applications within the plant [7,29].…”

“…In this work, three case studies are evaluated that differ on the utilization of different amounts of steelworks off-gases and on the end-product (methane and/or methanol). Those case studies are of particular interest to the steel industry and refer to the short-and medium-term deployment horizon of this technology, with the final aim to move towards the decarbonization of the steel industry [7].…”

“…This approach requires enormous amounts of subsidies, extensive infrastructure modification, as well as large amounts of electricity [4]. The second approach, which is investigated in this work, is to fully convert steelworks off-gases to useful products such as methane and methanol (MeOH), again using large amounts of renewable hydrogen [7,8]. In contrast to the first approach, there is no deviation from the existing steel production routes.…”

“…This approach uses this surplus to produce useful chemicals that have a significant market value (methanol) or can be used internally for power/heat generation (methane). The advantages of this approach are multi-fold since the external purchase of fossil-based methane is avoided; methanol is sold externally to generate additional revenues; and, simultaneously, an environmental problem is tackled [7]. To achieve the required stoichiometries for methanol synthesis and methanation, additional hydrogen is required, since the contained hydrogen in those off-gases is not sufficient for the synthesis processes [8].…”

Multi-agent systems to improve efficiency in steelworks

“…The project entitled "Integrated and intelligent upgrade of carbon sources through hydrogen addition for the steel industry" (i3upgrade), which is funded by Research Fund for Coal and Steel (RFCS) of European Union (EU), aims at efficiently managing process off-gases to increase the economic and environmental sustainability of the integrated steelworks production. Through the addition of H2 produced by electrolysis powered by renewable sources it is possible to reduce CO 2 emissions by improving the sustainability of the steel production cycle [37,38]. Another aspect covered by i3upgrade is the evaluation of long-term economic profitability of hydrogen-intensified syntheses in integrated steelworks as well as the derivation of potential business models and implementation strategies for the European steel industry and beyond.…”