Optimization-based technoeconomic analysis of molten-media methane pyrolysis for reducing industrial sector CO2 emissions

Abstract

The industrial sector accounts for nearly a quarter of global greenhouse gas emissions. To achieve climate change mitigation targets, reductions in energy-related and process emissions from industry are crucial. Methane pyrolysis could be used to produce low-carbon hydrogen (H₂) for distributed energy end-uses and for industrial processes while generating a solid carbon product that can be permanently sequestered or sold as a manufacturing feedstock. This work analyzes methane pyrolysis via a molten media that continuously catalyzes the reaction and separates the produced carbon. We perform design optimization to evaluate the technoeconomics of this technology. We model a template small-scale 50 MW boiler (10.4 ktonne per year H₂) as a base case for combustion applications, because such boilers are particularly challenging to decarbonize (are expensive to electrify and too small-scale for post-combustion CO₂ capture and sequestration (CCS)). We find that the levelized cost of low-carbon energy is $11.09 per MMBTU, equivalent to an abatement cost of $115 per tonne CO₂ avoided. In addition, we examine a policy-informed case study of H₂ production at refineries subject to the California Low Carbon Fuel Standard (LCFS). In the absence of CO₂ credits, the levelized cost of hydrogen is $1.75 per kg H₂, but when LCFS credits are included at recent prices of $190 per tonne CO₂ eq., we find a levelized cost of hydrogen as low as $0.39 per kg H₂. Optimization was conducted under a range of economic sensitivities, finding that, as long as catalyst losses can be minimized, costs could be competitive with decarbonization methods such as CCS or other low-carbon H₂ production pathways.