Department of Chemical Engineering
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Item Asymmetric mixed matrix membranes with zeolite imidazolate frameworks (ZIF-8, ZIF-67, bimetallic ZIF-8/67) and polyethersulfone for high flux and high selective hydrogen separation(Wiley, 2025-03) Pani, Ajaya Kumar; Kuncharam, Bhanu Vardhan ReddyFor producing high-purity hydrogen (H2) from hydrocarbon reforming, membrane-based separation can be used. In this study, mixed matrix polymer membranes using metal–organic framework (MOF) nanoparticles are explored to overcome the permeability-selectivity trade-off of traditional polymeric membranes. Highly permeable and highly H2 selective MMM using ZIF-8, ZIF-67, and bimetallic ZIF-8/67 MOFs were fabricated via a non-solvent induced phase inversion method by incorporating an intermediate solvent evaporation step. MMMs with 5, 10, and 15 wt.% of nanofillers loadings were prepared and tested for single gas (H2, CO2, CH4, and N2) permeability at 1–2 bar pressures. MMMs permeability and selectivities exceeded the Robeson upper bound (2008) for H2/CO2 separation, demonstrating the potential for obtaining high-purity hydrogen at low pressures. H2/N2 selectivity of 43.4, H2/CO2 selectivity of 27.86 for and H2/CH4 selectivity of 31.36 were obtained. Analytical techniques such as XRD, FTIR, and DSC were used to explain the transport mechanism in the MMMs. The cross-sectional structure and morphology of MMMs were analyzed with field-emission scanning electron microscope (FESEM) to provide insights into the membrane's porous structure.Item Multi-scale two-dimensional packed bed reactor model for industrial steam methane reforming(Elsevier, 2020-04) Kuncharam, Bhanu Vardhan ReddyA non-isothermal heterogeneous steady-state model was developed for a packed bed reactor for steam methane reforming employing a multi-scale approach. The model consists of two-dimensional fluid-phase mass and heat transport equations accounting for axial and radial dispersion in the reactor tube, as well as accounting for mass and heat transfer resistances at the fluid-solid phase boundary, calculated using empirical equations. Reaction, mass and heat transfer in the catalyst particle are directly coupled with the fluid-phase equations using a 1D pellet model, thus avoiding the use of a catalyst effectiveness factor for reaction. The performance of the packed-bed reactor is compared using three pressure drop equations: the Ergun equation which neglects wall effects and the Eisfeld-Schnitzlein and Di Felice-Gibilaro correlations which include them. This multi-scale model also accounts for the effects of temperature, pressure and molar change of gas species due to reaction on superficial velocity using a separate equation. The impact of neglecting these effects through simplified models is evaluatedItem Multi-scale two-dimensional packed bed reactor model for industrial steam methane reforming(Elsiever, 2020-04) Kuncharam, Bhanu Vardhan ReddyA non-isothermal heterogeneous steady-state model was developed for a packed bed reactor for steam methane reforming employing a multi-scale approach. The model consists of two-dimensional fluid-phase mass and heat transport equations accounting for axial and radial dispersion in the reactor tube, as well as accounting for mass and heat transfer resistances at the fluid-solid phase boundary, calculated using empirical equations. Reaction, mass and heat transfer in the catalyst particle are directly coupled with the fluid-phase equations using a 1D pellet model, thus avoiding the use of a catalyst effectiveness factor for reaction. The performance of the packed-bed reactor is compared using three pressure drop equations: the Ergun equation which neglects wall effects and the Eisfeld-Schnitzlein and Di Felice-Gibilaro correlations which include them. This multi-scale model also accounts for the effects of temperature, pressure and molar change of gas species due to reaction on superficial velocity using a separate equation. The impact of neglecting these effects through simplified models is evaluated.