(371an) Synthesis and Comparison of Carbon Dioxide Emissions Free Hydrogen Production

Hydrogen is being considered as a possible large-scale carbon-free industrial combustion and transportation fuel. Steam methane reforming (SMR) reaction is the most dominant industrial hydrogen production method. The SMR reaction is extremely endothermic, so the reaction equilibrium is favored by high temperatures. The significant heat required to drive the reaction is typically provided by external combustion of fossil fuels leading to substantial carbon dioxide emissions. Recently, there has been interest in producing hydrogen by water electrolysis using renewable electricity.

As more electricity is either renewable or otherwise carbon-free, powering more process industry operations with electricity becomes a decarbonization strategy. Electricity can generate heat via resistance, induction, dielectric, arc, and gas compression mechanisms, among others [1]. Electrically generated heat can be delivered with high precision and tight control. Furthermore, electricity can also facilitate chemical reactions that are thermodynamically difficult, especially the electrolysis of water to produce hydrogen. The key is to match the right electrical heating technology at the right temperature with the right application at the right scale.

This work uses an Attainable Region Framework to synthesize hydrogen production processes using carbon-free electricity as energy sources. We synthesize an SMR based hydrogen production process that uses electrically driven reactors and process units and also synthesize an electrolyzer based hydrogen production process. We integrate the Attainable Region analysis with process modeling and optimization techniques to identify optimal configurations for both process types and then compare different technological and economic factors such as efficiency, capital and operating costs.

[1] CM Masuku, RS Caulkins, JJ Siirola, Process decarbonization through electrification, Curr. Opin. Chem. Eng. 44 (2024) 101011.