Evaluating the Performance of a Ni Catalyst Supported on La2O3‑MgAl2O4 for Dry Reforming of Methane in a Packed Bed Dielectric Barrier Discharge Plasma Reactor
Asif Hussain Khoja,†,‡ Muhammad Tahir,† and Nor Aishah Saidina Amin*,†
Ni/La2O3-MgAl2O4 has been investigated for dry reforming of methane (DRM) in a cold plasma dielectric barrier discharge (DBD) ﬁxed-bed reactor. Ni/La2O3-MgAl2O4 was prepared according to the modiﬁed coprecipitation assisted hydrothermal method. The samples were characterized by X-ray diﬀraction (XRD), ﬁeld emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX) mapping, N2 adsorption−desorption, H2-TPR, CO2-TPD, the coaxial dielectric probe method, and thermogravimetric analysis (TGA). Incorporating web structured-like La2O3 into MgAl2O4 changes the irregular structure of MgAl2O4 into ﬂakes. The addition of La2O3 as a cosupport enhances the Ni−support interaction and basicity of Ni/La2O3-MgAl2O4. Ni/La2O3-MgAl2O4 signiﬁcantly improves the conversion of CH4 and CO2 to 86% and 84.5%, respectively. The selectivity for H2 and CO is 50% and 49.5%, respectively. The syngas ratio (H2/CO) signiﬁcantly improves from 0.86 to 1.01, while the overall energy eﬃciency is 26% higher than that of plasma only DRM. The enhanced DRM activity is ascribed to the higher basicity and better dielectric properties of the catalyst. The formation of intermediate carbonate (La2O2CO3) inhibited carbon deposition as evident by TGA and EDX mapping. Furthermore, the catalyst is also successfully regenerated, and stable DRM performance is maintained during cyclic runs. The stability of the reported plasma-catalyst system is encouraging for further investigation to make DBD plasma DRM economically viable.
click here to read more:
on 2015, Prof NASA was invited as a keynote speaker for ICOOPCHE 2015 in Riau. Here is a keynote speaker slide entitle “BIOMASS CONVERSION
TO BIO-BASED PRODUCTS”
slide keynote speaker ICOOPCHE Profnasa
The compact design of OzBiONY® system was successfully developed. The system is user friendly and safe for laboratory operation with automatic setting system equipped with exhaust fan. The dry ozone was supplied into the biomass surface in the horizontal reactor equipped with ribbon mixer and washing with NaOH for complete separation. The experimental results revealed 2.20 g/g material of glucose concentration yield was collected for pretreated OPF compare to 1.65 g/g material of glucose concentration yield for untreated OPF at moderate process conditions. By using dilute H2SO4 (4 wt%) as catalyst at moderate process condition (180°C, 1h), 2.5 wt.% LA yield was obtained using untreated OPF. In contrast, the hydrolysis process was enhanced by using ozonolysis pretreated OPF with the LA yield obtained was 13 wt.%, comparable with LA yield attained from commercial cellulose as feedstock (14 wt%). The new prototype pretreatment system is one-step closer to being commercialized.
OzBiONY system in laboratory
A new biomass pretreatment system known as OzBiONY tm has been developed. OzBiONY tm consists of three main parts: ozone generator, ozone reactor, and ozone destructor. Using oil palm fronds (OPF), the ozone pretreatment method degrades 90% lignin with 0.8 mm OPF particle size. The total reducing sugar (TRS) yield reveals about 33% of glucose recovery compared to raw OPF at moderate process conditions. Meanwhile, the levulinic acid (LA) yield is enhanced up to 4-fold at 180°C within 1h for TRS hydrolysis using dilute H2SO4 (4 wt%) compared to commercial cellulose. Moreover, this technology helps to mitigate the abundance of agricultural biomass and forest residue by utilizing the biomass for high value-added products.
The OzBiONY tM system is ready for commercialization to pretreat various LB feedstocks such as OPF, EFB, sugar bagasse and pineapple waste to cellulose-rich component. The cellulose obtained after the pretreatment process is comparable to the commercial microcrystalline cellulose.
This project has been awarded:
- Silver medal in INATEX 2019, UTM Johor Bahru, Johor
- Bronze medal in MRCIE 2015, UNiKL Pasir Gudang, Johor
- Silver medal in INATEX 2015, UTM Johor Bahru, Johor
- Gold Medal in INATEX 2016, UTM Johor Bahru, Johor
OzBIONY tm is a novel biomass pretreatment process to fractionate biomass into cellulose-rich and lignin-rich components without damaging its properties. By introducing dry ozone onto the biomass surface in a horizontal reactor equipped with a ribbon mixer, the lignin in the biomass could be degraded. Washing the degraded sample with NaOH could completely separate the biomass and obtain cellulose-rich component. The prototype is available for upgrading the reactor system to a smart machine for commercial applications. The name of the process have been file in class 42.
Well-designed Ag-La modified protonated graphitic carbon nitride nanotubes (pCNNT) are fabricated via a template-free sonicated assisted one-pot hydrothermal method. The structure and properties of the catalyst samples are obtained by XRD, SEM, TEM, EDX, N2-sorption, XPS, UV–vis DRS and PL spectroscopy characterization techniques. The effect of Ag-La-modified pCNNT is evaluated for different CH4 reforming processes such as dry reforming of methane (DRM) and bi-reforming of methane (BRM), carried out in a fixed-bed and monolithic honeycomb photoreactor systems under UV and visible light irradiations. The optimized 3%Ag-5%La/pCNNT performance displayed increased productivity under UV-light due to more production of charges with strong ability for cleaving both stable CO2 and CH4 molecules. More importantly, the performance of Ag-La loaded pCNNT is 1.45 and 2.10 folds higher for CO and H2 production, respectively compared with Ag-La loaded pCN nanosheets. CO and H2 evolutions prevailed in a monolith photoreactor compared to fixed-bed reactor. Besides, the amount of CO, H2 and CH3OH are 1.79, 2.12 and 2.13 folds higher in BRM compared to DRM. The improved performance can be ascribed to effective interfacial carrier separation due to Ag-La synergistic effect with suitable redox potentials for BRM process. The quantum yield is significantly enhanced with BRM in the monolithic honeycomb photoreactor loaded with Ag-La modified pCNNTs due to greater photon energy utilization, larger illuminated surface area, improved sorption process and surface reactions with efficient charge carrier utilization for CO2 reduction and CH4/H2O oxidation. Reaction mechanism is proposed to commensurate with the performance of Ag-La/pCNNT for BRM process based on characterization analysis and experimental results. The experimental results could provide guidance for further development of advanced and highly efficient hetero-structures for photocatalytic BRM applications.
- Tahir, B., Tahir, M. and Amin, N. (2019). Ag-La loaded protonated carbon nitrides nanotubes (pCNNT) with improved charge separation in a monolithic honeycomb photoreactor for enhanced bireforming of methane (BRM) to fuels. Applied Catalysis B: Environmental, 248, pp.167-183.
The synthesis of ethyl levulinate, a fuel additive, by catalytic esterification of levulinic acid with ethanol over carbon cryogel has been investigated. The carbon cryogel catalyst, coupled with a large surface area and strong acidity, has been identified as an effective carbon-based catalyst for obtaining high ethyl levulinate yield of 86.5 mol%. The pseudo-homogeneous kinetic model is adopted to evaluate the different reaction orders. The first-order pseudo-homogeneous model is considered most suitable (R2 > 0.98) while the selection of kinetic model is also clarified and supported by the linearity of the parity plot. The activation energy of the esterification reaction is estimated to be 20.2 kJ/mol. Based on the thermodynamic activation parameters, the reaction is classified as endergonic and more ordered. The results from this study could provide valuable information for reactor modeling and simulation purposes in the future.
- Zainol, M., Amin, N. and Asmadi, M. (2018). Kinetics and thermodynamic analysis of levulinic acid esterification using lignin-furfural carbon cryogel catalyst. Renewable Energy, 130, pp.547-57.
- DOI :https://doi.org/10.1016/j.renene.2018.06.085