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 Low temperature steam reforming of ethanol over cobalt doped bismuth vanadate [Bi4(V0.90Co0.10)2O11-δ (BICOVOX)] catalysts for hydrogen production(Elsevier, 2021-01) Roy, BanasriThe atmospheric pressure low temperature steam reforming of ethanol over Bi4(V0.90Co0.10)2O11-δ (BICOVOX) catalysts, synthesize by a solution combustion synthesis method and calcined at 400, 600 and 800 °C, has been investigated at different reactor temperatures, H2O: EtOH molar ratios and feed flow rates. For fresh catalysts amount, crystallinity and particle size of pure γ-BICOVOX phase is observed to increase with increasing calcination temperature. Phase purity and crystallinity of the catalysts are almost retained till 30 h of activity study with some amount of carbon formation as derived from XRD, XPS, FESEM and simultaneous DTA-TGA study. Catalyst calcined at 600 °C (BICOVOX-600) exhibits the highest ethanol conversion (100%) with maximum H2 selectivity (80%) under reaction conditions of 400 °C, 23:1H2O: EtOH molar ratio and 0.35 cc min−1 feed flow rate. The maximum O2− vacancy present in lattice and lowest coke deposition could explain the best performance of BICOVOX-600 catalyst.Item A review on ethanol steam reforming for hydrogen production over Ni/Al2O3 and Ni/CeO2 based catalyst powders(Elsevier, 2022-02) Srinivas, Appari; Roy, BanasriHydrogen is contemplated as an alternative clean fuel for the future. Ethanol steam reforming (ESR) is a carbon-neutral, sustainable, green hydrogen production method. Low cost Ni/Al2O3 and Ni/CeO2 powder catalysts demonstrate high ESR activity. However, acidic nature of Al2O3 and instability of CeO2 lead to deactivation of the catalysts easily. This article examines the research articles published on the modification of Ni by various noble and non-noble metals and on alteration of the supports by different metal oxides in detail and their effect on ESR all through 2000–2021. The ESR reaction mechanisms on Ni/Al2O3 and Ni/CeO2 powder catalysts and basic thermodynamics for different possible reactions and H2 yield are explored. Manipulation of catalyst morphology (surface area and particle size) via preparation method, selection of active metal promoter and support modifier are found to be significantly important for H2 production and minimizing carbon deposition on catalysts.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.Item Recent progress in thermochemical techniques to produce hydrogen gas from biomass: A state of the art review(Elsiever, 2019-10-04) Sheth, P.N.The present work comprehensively covers the literature that describes the thermochemical techniques of hydrogen production from biomass. This survey highlights the current approaches, relevant methods, technologies and resources adopted for high yield hydrogen production. Prominent thermochemical methods i.e. pyrolysis, gasification, supercritical water gasification, hydrothermal upgrading followed by steam gasification, bio-oil reforming, and pyrolysis inline reforming have been discussed thoroughly in view of the current research trend and latest emerging technologies. Influences of important factors and parameters on hydrogen yield, such as biomass type, temperature, steam to biomass ratio, retention time, biomass particle size, heating rate, etc. have also been extensively studied. Catalyst is a vital integrant that has received enough attention due to its encouraging influence on hydrogen production. Literature confirms that hydrogen obtained from biomass has high-energy efficiency and potential to reduce greenhouse gases hence, it deserves versatile applications in the coming future. The study also reveals that hydrogen production through steam reforming, pyrolysis, and in-line reforming deliver a considerable amount of hydrogen from biomass with higher process efficiency. It has been identified that higher temperature, suitable steam to biomass ratio and catalyst type favor useful hydrogen yield. Nevertheless, hydrogen is not readily available in the sufficient amount and production cost is still high. Tar generation during thermochemical processing of biomass is also a concern and requires consistent efforts to minimize it.