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Records with Keyword: Steam Reforming
Dynamic Modeling and Control of a Coupled Reforming/Combustor System for the Production of H2 via Hydrocarbon-Based Fuels
Dimitris Ipsakis, Theodoros Damartzis, Simira Papadopoulou, Spyros Voutetakis
April 27, 2021 (v1)
Keywords: C1–C4 feedstock, distributed control system, Dynamic Modelling, hydrogen production, PID control, Steam Reforming
The present work aims to provide insights into the dynamic operation of a coupled reformer/combustion unit that can utilize a variety of saturated hydrocarbons (HCs) with 1−4 C atoms towards H2 production (along with CO2). Within this concept, a preselected HC-based feedstock enters a steam reforming reactor for the production of H2 via a series of catalytic reactions, whereas a sequential postprocessing unit (water gas shift reactor) is then utilized to increase H2 purity and minimize CO. The core unit of the overall system is the combustor that is coupled with the reformer reactor and continuously provides heat (a) for sustaining the prevailing endothermic reforming reactions and (b) for the process feed streams. The dynamic model as it is initially developed, consists of ordinary differential equations that capture the main physicochemical phenomena taking place at each subsystem (energy and mass balances) and is compared against available thermodynamic data (temperature and concent... [more]
Ultra-Pure Hydrogen via Co-Valorization of Olive Mill Wastewater and Bioethanol in Pd-Membrane Reactors
David Alique, Giacomo Bruni, Raúl Sanz, José Antonio Calles, Silvano Tosti
April 14, 2020 (v1)
Keywords: bioethanol, Hydrogen, membrane reactor, olive mill wastewater, palladium membrane, Steam Reforming
Olive mill wastewater (OMW) presents high environmental impact due to the fact of its elevated organic load and toxicity, especially in Mediterranean countries. Its valorization for simultaneous pollutants degradation and green energy production is receiving great attention, mainly via steam reforming for hydrogen generation. Following previous works, the present research goes into detail about OMW valorization, particularly investigating for the first time the potential benefits of OMW−bioethanol mixtures co-reforming for ultra-pure hydrogen production in Pd-membrane reactors. In this manner, the typical large dilution of OMW and, hence, excess water can be used as a reactant for obtaining additional hydrogen from ethanol. Fresh OMW was previously conditioned by filtration and distillation processes, analyzing later the effect of pressure (1−5 bar), oxidizing conditions (N2 or air as carrier gas), gas hourly space velocity (150−1500 h−1), and alcohol concentration on the co-reforming... [more]
Production of Hydrogen by Methane Steam Reforming Coupled with Catalytic Combustion in Integrated Microchannel Reactors
Junjie Chen, Baofang Liu, Xuhui Gao, Deguang Xu
September 21, 2018 (v1)
Keywords: catalytic combustion, Computational Fluid Dynamics, hydrogen production, Process Intensification, process optimization, Steam Reforming, thermal management, thermally integrated microchannel reactors
This paper addresses the issues related to the rapid production of hydrogen from methane steam reforming by means of process intensification. Methane steam reforming coupled with catalytic combustion in thermally integrated microchannel reactors for the production of hydrogen was investigated numerically. The effect of the catalyst, flow arrangement, and reactor dimension was assessed to optimize the design of the system. The thermal interaction between reforming and combustion was investigated for the purpose of the rapid production of hydrogen. The importance of thermal management was discussed in detail, and a theoretical analysis was made on the transport phenomena during each of the reforming and combustion processes. The results indicated that the design of a thermally integrated system operated at millisecond contact times is feasible. The design benefits from the miniaturization of the reactors, but the improvement in catalyst performance is also required to ensure the rapid pr... [more]
Effects of Catalysts and Membranes on the Performance of Membrane Reactors in Steam Reforming of Ethanol at Moderate Temperature
Manabu Miyamoto, Yuki Yoshikawa, Yasunori Oumi, Shin-ichi Yamaura, Shigeyuki Uemiya
July 30, 2018 (v1)
Keywords: amorphous alloy membranes, Ethanol, membrane reactor, Steam Reforming
Steam reforming of ethanol in the membrane reactor using the Pd77Ag23 membrane was evaluated in Ni/CeO₂ and Co/CeO₂ at atmospheric pressure. At 673 K, the H₂ yield in the Pd77Ag23 membrane reactor over Co/CeO₂ was found to be higher than that over Ni/CeO₂, although the H₂ yield over Ni/CeO₂ exceeded that over Co/CeO₂ at 773 K. This difference was owing to their reaction mechanism. At 773 K, the effect of H₂ removal could be understood as the equilibrium shift. In contrast, the H₂ removal kinetically inhibited the reverse methane steam reforming at low temperature. Thus, the low methane-forming reaction rate of Co/CeO₂ was favorable at 673 K. The addition of a trace amount of Ru increased the H₂ yield effectively in the membrane reactor, indicating that a reverse H₂ spill over mechanism of Ru would enhance the kinetical effect of H₂ separation. Finally, the effect of membrane performance on the reactor performance by using amorphous alloy membranes with different compositions was evalua... [more]
Dynamic modeling of integrated mixed reforming and carbonless heat systems
Leila Hoseinzade, Thomas A. Adams II
June 12, 2018 (v1)
Keywords: Carbonless Heat, Dry Reforming, Dynamic Modelling, Integrated Systems, Steam Reforming, Syngas
In the previous study, a dynamic and two-dimensional model for a steam methane reforming process integrated with nuclear heat production was developed. It was shown that the integrated high temperature gas-cooled reactor (HTGR)/steam methane reforming (SMR) is an efficient process for applications such as hydrogen production. In this study, it is demonstrated that combining nuclear heat with the mix of steam and dry reforming process can be a promising option to achieve certain desired H2/CO ratios for Fischer-Tropsch or other downstream energy conversion processes. The model developed in the previous study is extended to the combined steam and dry reforming process. The resulting model was validated using reported experimental data at non-equilibrium and equilibrium conditions. The dynamic and steady state performance of the integrated mixed reforming of methane and nuclear heat system was studied and it was found that in addition to desired H2/CO ratios, higher methane conversion and... [more]
Biomass-Gas-and-Nuclear-To-Liquids Aspen Plus Simulations
Leila Hoseinzade, Thomas A. Adams II
December 7, 2018 (v2)
In this paper, several new processes are proposed which co-generate electricity and liquid fuels (such as diesel, gasoline, or dimethyl ether) from biomass, natural gas and heat from a high temperature gas-cooled reactor. This carbonless heat provides the required energy to drive an endothermic steam methane reforming process, which yields H2-rich syngas (H2/CO>6) with lower greenhouse gas emissions than traditional steam methane reforming processes. Since downstream Fischer-Tropsch, methanol, or dimethyl ether synthesis processes require an H2/CO ratio of around 2, biomass gasification is integrated into the process. Biomass-derived syngas is sufficiently H2-lean such that blending it with the steam methane reforming derived syngas yields a syngas of the appropriate H2/CO ratio of around 2. In a prior work, we also demonstrated that integrating carbonless heat with combined steam and CO2 reforming of methane is a promising option to produce a syngas with proper H2/CO ratio for Fischer... [more]
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