Regular Article

Hydrogen role in the valorization of integrated steelworks process off-gases through methane and methanol syntheses^☆

¹ Scuola Superiore Sant’Anna, TeCIP Institute – ICT-COISP, Via Moruzzi 1, 56124 Pisa, Italy
² Chemical Process & Energy Resources Institute, Centre for Research and Technology Hellas, 6th km Charilaou-Thermi Road, 57001 Thessaloniki, Greece
³ K1-MET GmbH, Stahlstraße 14, 4020 Linz, Austria
⁴ Friedrich-Alexander-Universität Erlangen-Nürnberg, Chair of Energy Process Engineering, Fürther Str. 244f, 90429 Nuremberg, Germany
⁵ Montanuniversität Leoben, Chair of Process Technology & Industrial Environment Protection, Franz-Josef-Str. 18, 8700 Leoben, Austria
⁶ Air Liquide Research & Development, Innovation Campus Frankfurt, Air Liquide Forschung & Entwicklung GmbH, Gwinnerstraße 27-33, 60388 Frankfurt, Germany
⁷ voestalpine Stahl GmdH, Research and Development Ironmaking, Technical Department, Business Unit Slab, voestalpine-Strasse 3, 4020 Linz, Austria
⁸ Central Mining Institute, Plac Gwarkow 1, 40-166 Katowice, Poland

^* e-mail: i.matino@santannapisa.it

Received: 15 September 2021
Accepted: 27 January 2022

Abstract

The valorization of integrated steelworks process off-gases as feedstock for synthesizing methane and methanol is in line with European Green Deal challenges. However, this target can be generally achieved only through process off-gases enrichment with hydrogen and use of cutting-edge syntheses reactors coupled to advanced control systems. These aspects are addressed in the RFCS project i³upgrade and the central role of hydrogen was evident from the first stages of the project. First stationary scenario analyses showed that the required hydrogen amount is significant and existing renewable hydrogen production technologies are not ready to satisfy the demand in an economic perspective. The poor availability of low-cost green hydrogen as one of the main barriers for producing methane and methanol from process off-gases is further highlighted in the application of an ad-hoc developed dispatch controller for managing hydrogen intensified syntheses in integrated steelworks. The dispatch controller considers both economic and environmental impacts in the cost function and, although significant environmental benefits are obtainable by exploiting process off-gases in the syntheses, the current hydrogen costs highly affect the dispatch controller decisions. This underlines the need for big scale green hydrogen production processes and dedicated green markets for hydrogen-intensive industries, which would ensure easy access to this fundamental gas paving the way for a C-lean and more sustainable steel production.