Optimisation of low-carbon hydrogen production via sorption enhanced autothermal membrane technology and ammonia cracking
File(s)
Author(s)
Eluwah, Chidozie
Type
Thesis
Abstract
This PhD thesis presents the development and optimization of innovative hydrogen production technologies for sustainable, low-carbon fuel generation. The research focuses on three key innovations: The Industrial Sorption Enhanced Autothermal Membrane (ISEAM) process for blue hydrogen production, the Hybrid Air-Volt Ammonia Cracker (HAVAC) for centralized ammonia cracking, and a novel on-board ammonia cracker for light-duty fuel cell vehicles. The research methodology is underpinned by rigorous process flowsheeting and numerical modelling techniques, developed to simulate and evaluate the performance of the proposed processes. The modelling framework is validated against existing experimental data and benchmarks reported in peer-reviewed literature, with reference to established studies conducted by reputable research groups in the field. By drawing on this body of experimental work, the reliability and accuracy of the simulation outputs are enhanced, ensuring that the models presented reflect practical operating behaviour and remain grounded in experimentally observed phenomena. The ISEAM process advances blue hydrogen production by integrating membrane separation, sorption-enhanced reforming, and chemical looping combustion technologies. It achieves high-purity hydrogen (99.99%) with a production efficiency of 97.5% and methane conversion rates exceeding 99.9%. Compared to conventional steam methane reforming (SMR), ISEAM shows ≥ 32% improvements in most of the technical parameters that were evaluated and reduces the levelized cost of hydrogen (LCOH) by 37.5% and CO₂ removal costs by 57.5%, offering a cost-effective and sustainable solution for industrial-scale hydrogen production.
The HAVAC process introduces a dual-fuel capability, enabling ammonia cracking to produce hydrogen using either renewable electricity or an autothermal ammonia-air mixture. With ammonia conversion rates of up to 99.4% and hydrogen yields ranging from 84% to 99.5%, HAVAC offers high flexibility and efficiency. Its thermal efficiency of 94-95% outperforms traditional ammonia cracking technologies. The process demonstrates financial viability with a competitive LCOH between $4.10/kg-H₂ and $4.73/kg-H₂.
The HAVAC process introduces a dual-fuel capability, enabling ammonia cracking to produce hydrogen using either renewable electricity or an autothermal ammonia-air mixture. With ammonia conversion rates of up to 99.4% and hydrogen yields ranging from 84% to 99.5%, HAVAC offers high flexibility and efficiency. Its thermal efficiency of 94-95% outperforms traditional ammonia cracking technologies. The process demonstrates financial viability with a competitive LCOH between $4.10/kg-H₂ and $4.73/kg-H₂.
Version
Open Access
Date Issued
2025-04-17
Date Awarded
01/11/2025
License URL
Advisor
Fennell, Paul
Publisher Department
Department of Chemical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)