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

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.

Valorizing Steelworks Gases by Coupling Novel Methane and Methanol Synthesis Reactors with an Economic Hybrid Model Predictive Controller

“…The first phase of the simulation campaign was devoted to a fine tuning of the controller and optimizer parameters to balance the aggressiveness of the control action on the plants and the computational time; some simulated control trends were reported in [56,59] where the results of a preliminary investigation on economic cost improvement were also presented. In [59], the authors reported a first attempt at sensitivity analysis, varying the price of renewable sources of electricity for producing green hydrogen, and an estimate of CO 2 emission reductions.…”

“…The COG was exploited only in the PP, while the produced methane was distributed to the PP and market with a certain variability. Regarding the CO 2 reduction in the SC1 period, an approximate evaluation was conducted by starting from the rough estimate provided in [59]. The reduction in CO 2 in the SC1 period was about 1151 t, corresponding to a reduction of about 62% with respect to the CO 2 emissions that would have been obtained by feeding the same amount of POGs exploited in the synthesis reactors directly to a power plant.…”

Hydrogen intensified synthesis processes to valorise process off-gases in integrated steelworks

“…Their composition makes them suitable to be valorised both energetically and chemically. Currently, POGs are generally exploited to produce heat and electricity to satisfy the internal demands [9] and different research works on this topic can be found in literature for the optimisation of POGs distribution for thermal and energetic usage [10][11][12].…”

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

“…The global leaders in steel production are currently investigating and developing processes to almost completely de-fossilize their conventional steelmaking processes. There are two main approaches which, in their full Energies 2022, 15, 4650 2 of 26 deployment, both require large amounts of renewable hydrogen [5,6]. The first approach requires the development of new production processes and differ from the current processes which are already exhaustively optimized.…”