Economic analysis with multiscale high-throughput screening for covalent organic framework adsorbents in ammonia-based green hydrogen separation

Abstract

Because green ammonia is an emerging transportation medium for carbon-free hydrogen, technologies for efficient and cost-effective separation and purification of green hydrogen have attracted significant attention in recent years. Among the various options for hydrogen separation, pressure swing adsorption (PSA) has the highest technology readiness level, but the optimal adsorbent for this application is still under investigation. This study evaluates the viability of covalent organic framework (COF) adsorbents for ammonia-based green hydrogen separation processes. The feasibility of the adsorbents was estimated based on the economic analysis of the entire green hydrogen production process with a newly proposed multiscale high-throughput screening (HTS) approach. This approach addresses an existing knowledge gap, where the molecular- and process-scale viewpoints are not fully considered together during adsorbent evaluation. The proposed HTS approach incorporates a new algorithm for simulations with reduced computational cost and a procedure for estimating the economic viability of the adsorbents. The results show that among 648 COFs in a COF database, MPCOF was the most efficient for ammonia-based green H2 separation with a H2 recovery of 72% and levelized cost of USD 8.30/kg H2. This result was obtained with only 31% of the computational cost required by an existing HTS approach.