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Modeling and scaling processes to generate high-pressure hydrogen (H2) from ammonia

Problem statement

The increasing world energy demand accelerates the depletion of fossil fuels, which consequently boosts the research and development of alternative and viable energy sources. Ammonia (NH3) is a dense, carbon-free energy and hydrogen vector. It can provide on-site hydrogen via catalytic decomposition or cracking.

Our work covers the fundamentals of the microkinetics (using benchmark catalysts such as Ru-based and cheaper, novel alternatives such as Co-Ba-Ce-based) to the reactor modeling.

We use DFT-guided and microkinetic modeling to help understand the rates and catalyst performance. Whereas the reactor modeling from the laboratory scale to the industrial-scale mandates considering the heat-mass transfer effects for efficient implementation of the process.

Goals

  • Develop a microkinetic modeling framework to analyze the catalyst performance and the effect of the role of promoters
  • Dimensionless number analysis to transcend the scale of operation and scale up
  • Using reactive computational fluid dynamics and process modeling: model and simulate an ammonia cracker unit at different scales, including a repurposed steam reformer
  • Model and simulate different reactor configurations, such as packed bed reactors with and without membranes
AMD

Related People

Gontzal Lezcano

Related Publications

Modeling-aided coupling of catalysts, conditions, membranes, and reactors for efficient hydrogen production from ammonia

by Realpe, Kulkarni, Cerrillo, Morlanes, Lezcano, Kekalainen, Paglieri, Rakib, Solami, Gascon, Castaño
React. Chem. Eng. Year: 2023 DOI: https://doi.org/10.1039/D2RE00408A

Abstract

The production of high-purity, pressurized hydrogen from ammonia decomposition in a membrane catalytic reactor is a feasible technology. However, because of the multiple coupled parameters involved in the design of this technology, there are extensive opportunities for its intensification. We investigated the coupling between the type of catalyst, process conditions, type of membrane, and reactor operation (isothermal and non-isothermal) in the catalytic decomposition of ammonia. First, we developed an agnostic dimensionless model and calculated the kinetic parameters for a set of lab-made Ru- and Co-based catalysts and the permeation parameters of a Pd–Au membrane. The non-isothermal model for the Pd–Au membrane reactor was validated with the experiments using Co-based catalysts. Finally, we analyzed the coupling conditions based on the model predictions, results obtained in the literature and our experimental results, including several case studies. The thorough analysis led us to identify optimized combinations of catalyst–conditions–membrane–reactor that yield similar or improved results compared to the ones of Ru-based catalyst in a non-membrane reactor. Our results indicate that optimizing a single factor, such as the catalyst, may not lead to the desired outcome and a more holistic approach is necessary to produce pressurized and pure hydrogen efficiently.

Keywords

AMD MKM