Comprehensive parametric investigation of methane reforming and hydrogen separation using a CFD model

[Display omitted] •Comprehensive parametric study of membrane integrated reforming reactor (MRR)•Sweeping steam on the permeate side increases H2 recovery and CH4 conversion.•Flow direction of permeate had no effect on CH4 conversion or H2 recovery.•Longer reactor length results in better CH4 conver...

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Bibliographic Details
Published in:	Energy conversion and management Vol. 249; p. 114838
Main Authors:	Ben-Mansour, Rached, Azazul Haque, M.D., Harale, Aadesh, Paglieri, Stephen N., Alrashed, Firas S., Raghib Shakeel, Mohammad, Mokheimer, Esmail M.A., Habib, Mohamed A.
Format:	Journal Article
Language:	English
Published:	Oxford Elsevier Ltd 01-12-2021 Elsevier Science Ltd
Subjects:	CAD Carbon dioxide Carbon sequestration Catalysts Computational fluid dynamics Computer aided design Computer applications Conversion Emissions Energy consumption Flow rates Fluid dynamics Greenhouse gases Hydrodynamics Hydrogen Hydrogen production Hydrogen-selective membrane Mass flow rate Mathematical models Membranes Methane Nuclear fuels Recovery Reforming Steam flow Steam-methane reforming Sweep flow effect Sweeping Hydrogen-selective membrane Steam-methane reforming Sweep flow effect Hydrogen production
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Summary:	[Display omitted] •Comprehensive parametric study of membrane integrated reforming reactor (MRR)•Sweeping steam on the permeate side increases H2 recovery and CH4 conversion.•Flow direction of permeate had no effect on CH4 conversion or H2 recovery.•Longer reactor length results in better CH4 conversion and H2 recovery.•Retentate side high pressures decreases CH4 conversion but increases H2 permeation.•Optimum performance requires moderate retentate pressure and steam sweeping. Steam-methane reforming is the primary method for industrial hydrogen production. High energy consumption and elevated greenhouse gas (GHG) emissions call for a significant improvement in the reforming process for optimum methane conversion and hydrogen production. Enhanced fuel conversion also produces more CO2 than CO, making the carbon capture process easier, consequently reducing harmful emissions. In this work, a membrane-integrated reformer reactor (MRR) has been investigated through an experimentally validated computational fluid dynamics (CFD) model using ANSYS-Fluent. The MRR model constitutes of Ni-based catalyst filled reforming zone, Pd-based hydrogen-selective membrane, and permeate zone for hydrogen recovery. The developed model has been examined for several parameters including steam-to-methane ratio, flow rate, sweeping conditions, flow direction, reformer pressure and membrane length. The results indicated a substantial increase in methane conversion with a higher steam-to-carbon (S/C) ratio for a given feed flow rate. The methane conversion increased from 34% to 63% when the S/C ratio is increased from 2 to 6 at a methane mass flow rate of 0.0018 kg/s. The results also indicate an increase in hydrogen recovery with the decrease in feed flow rate for a fixed steam-to-methane ratio. Hydrogen recovery decreased from 28% to 2% when the mass flow rate of methane is increased from 5 × 10-5 kg/s to 1.8 × 10-3 kg/s, at a fixed S/C of 4. The incorporation of sweeping steam demonstrated a significant improvement in hydrogen recovery increasing from 15% to 33% with a sweep flow rate equal to the feed flow rate and methane mass flow rate of 1.8 × 10-4 kg/s. Further increase in sweep flow rate showed very small increase in hydrogen recovery, therefore in order to minimize the use of sweeping steam, a sweeping steam flow rate equal to the feed flow rate is suggested. Furthermore, flow direction, reformer pressure and membrane length were also found to play vital role in MRR performance.
ISSN:	0196-8904 1879-2227
DOI:	10.1016/j.enconman.2021.114838