(631b) Process Modeling and Optimal Operational Strategies for Integrated Chemical Looping Hydrogen Production and Biomass Gasification Under Feedstock Uncertainty

The escalating environmental concerns and the critical need for sustainable energy solutions have heightened the interest in hydrogen as a clean, renewable energy carrier. Steam methane reforming, while the most common and developed method of hydrogen production process, is hampered by its complex structure and significant carbon dioxide emissions, contributing to environmental pollution. Efforts to incorporate carbon capture and storage systems to mitigate these emissions introduce prohibitive costs. Moreover, water electrolysis, despite being a promising method for hydrogen production, faces challenges due to high capital and operational costs associated with membrane separation and acid-stable catalysts. As an alternative to address these issues, chemical looping hydrogen production (CLHP) has emerged, offering a simpler configuration and eliminating the need for expensive additional units through its in-situ carbon dioxide capture unit [1]. This presents CLHP as a cost-effective and environmentally friendly method for hydrogen production, with many studies currently being conducted on its potential benefits.

Ongoing research in CLHP primarily utilizes iron-based oxygen carriers due to their favorable thermodynamics for higher steam reactor conversion efficiency, low raw material costs, and environmentally friendly properties. Despite these advantages, iron-based carriers exhibit poor catalytic activity and low water splitting conversion in steam reactors, necessitating an additional air reactor due to insufficient oxidation. In contrast, perovskite oxygen carriers demonstrate significantly enhanced catalytic efficiency, resulting in higher conversion rates in water splitting [2]. Moreover, CLHP process demonstrates higher efficiency in converting gas fuels compared to solid fuels, leading to extensive research focused on gas fuels such as natural gas. For hydrogen to be recognized as a sustainable energy resource, ensuring its derivation from carbon-neutral sources (i.e., biomass) is crucial. In existing studies integrating chemical looping processes with biomass gasification for process modeling, variables (e.g., biomass composition, steam to biomass ratio, and gasification temperature) have been examined to determine optimal operational conditions [3,4]. However, the biomass gasification process involves uncertainties related to the quality of biomass feedstock (e.g., ash, moisture, carbon, hydrogen, and oxygen content), which impact the syngas yield and composition [5]. Variations in syngas yield and composition sequentially impact CLHP operational condition. Additional research is necessary to understand the impacts of these uncertainties on CLHP and to establish optimal operational conditions under these conditions.

Acknowledging these research gaps, this work conducts process modeling for a combined chemical looping process with biomass gasification utilizing a perovskite-based oxygen carrier in the reaction. Subsequently, the developed model is validated using experimental results and applied to determine the optimal operating conditions of the integrated CLHP process, considering uncertainties such as variations in biomass composition resulting from the biomass gasification process. To verify the economic and environmental feasibility of the integrated process under the identified optimal operating conditions, in this work, techno-economic analysis and carbon dioxide life cycle assessment are conducted using process simulation results. Notably, this research provides more accurate operational insights by understanding the effects of uncertainties in the advanced CLHP process.

Reference

[1] Paolo Chiesa, Giovanni Lozza, Alberto Malandrino, Matteo Romano, Vincenzo Piccolo, “Three-reactors chemical looping process for hydrogen production,” International Journal of Hydrogen Energy, Volume 33, Issue 9, 2233-2245, 2008.

[2] Yikyeom Kim, Hyun Suk Lim, Hyeon Seok Kim, Minbeom Lee, Jae W. Lee, Dohyung Kang, “Carbon dioxide splitting and hydrogen production using a chemical looping concept: A review,” Journal of CO2 Utilization, Volume 63, 2022.

[3] Mehdi Mehrpooya, Mohammad Mehdi Moftakhari Sharifzadeh, Mahsa Rajabi, Mortaza Aghbashlo, Meisam Tabatabai, Soleiman Hosseinpour, Seeram Ramakrishna, “Design of an integrated process for simultaneous chemical looping hydrogen production and electricity generation with CO2 capture,” International Journal of Hydrogen Energy, Volume 42, Issue 12, pp. 8486-8496, 2017.

[4] Onur Oruc, Ibrahim Dincer, “Evaluation of hydrogen production with iron-based chemical looping fed by different biomass,” International Journal of Hydrogen Energy, Volume 45, Issue 60, pp. 34557-34565, 2020.

[5] Yi Fang, Li Ma, Zhiyi Yao, Wangliang Li, Siming You, “Process optimization of biomass gasification with a Monte Carlo approach and random forest algorithm,” Energy Conversion and Management, Volume 264, 2022.