This paper investigates process modelling and reactor design for the reducer in the chemical looping hydrogen production (CLHP) process. The CLHP process adopts a three-reactor technology that can ...provide an efficient and sustainable alternative to the current hydrogen production technology via steam methane reforming (SMR), which suffers from several limitations during industrial operation. CLHP can achieve higher thermal efficiency than SMR and provide a carbon capture and storage (CCS) system. So far, no report on the modelling analysis of the reducer despite its critical dependence on temperature. The modelling study adopts the modified pellet-grain model at the micro-scale and counter-current moving bed model reactor at the reactor level. Simulation results of the gas-solid behavior based on the multi-scale model agree with the literature evidence. Critical information from the model revealed that the oxygen carriers (solids) can attain a desired state, but the syngas remains underutilized. The model simulation further suggests that lowering the gas-solid velocity ratio (Vgs) can substantially promote the syngas conversion. However, the Vgs value must remain above a threshold value (170), defined through the limitation of gas-solid velocities in a moving bed reactor. Since a CCS system requires high purity (>95%) of the product gas, rigorous temperature-pellet size optimization is vital to achieving the target purity while maintaining desired solid state.
This article thoroughly assesses the Chemical Looping Hydrogen Production (CLHP) process, aiming to enhance understanding of detailed dynamic simulations. It includes a concise historical overview of ...chemical looping technology, emphasizing recent commercial applications like combustion engines. The article discusses several cases of pilot and sub-pilot scale investigations, along with critical insights to identify the issues surrounding the commercialization of this technology. Furthermore, the review is extended to analyze several aspects of the process to develop a dynamic simulation model, including reactants, operating modes, kinetic parameters, and the process models. Key process materials such as reduction fuel, oxygen carriers and solid supports are carefully chosen to achieve target conversions and net-zero carbon emissions. The three-reactor system is meticulously defined, focusing on closed-loop production's thermodynamic and economic benefits. Detailed information is provided on reactions within each unit and the required operating regimes for continuous solid circulation. The review also examines mathematical modeling methods for dynamic simulation implementation to determine gas-solid profiles at pellet and reactor scales. Simulations derived from this study's concepts can be refined through parameter modification for optimal process operation and control system analysis for real-world industrial applications. Ultimately, this review contributes significantly to the commercialization of CLHP, offering an economically viable solution for sustainable hydrogen production.
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•Chemical looping is an economically viable solution for producing hydrogen fuel.•Dynamic models can further the knowledge of chemical looping hydrogen production.•Mathematical simulations can quantify the acclaimed advantages of the process.•Quantified results can drive further investment towards process industrialization.
In this article, Chemical Looping Hydrogen Production (CLHP) technology is investigated as a potential substitute for the existing Steam Methane Reforming (SMR) process. CLHP is preferred over ...conventional methods due to thermodynamic advantages and inherent carbon capture capabilities, demonstrating sustainability criteria along with economic efficiency. Through this comprehensive review, we analyze the reactor design and control criteria involved in the development of dynamic models for this hydrogen (H2) production process. The selection of process reactants, along with key specifications of each reactor was reviewed as an initial basis for developing the simulation model. Additionally, the reactor operation modes were compared based on their performance capabilities in CLHP. Finally, gas-solid reaction models were reviewed, along with additional derivations to develop a realistic process simulation. This study highlights the importance of dynamic modelling for optimization and control system analysis. In-depth analysis of processes through dynamic simulations provides the necessary information to design a large-scale production plant. Therefore, this article contributes to research pursuing process engineering and equipment design of the CLHP method, aimed at its commercialization.
