Optimization of praseodymium oxide based catalysts for methanation reaction of simulated natural gas using Box-Behnken design

Malaysia energy demand on natural gas is increasing, leading to the purification of sour natural gas through the removal of carbon dioxide using catalytic conversion technique. Praseodymium oxide is preferred due to its properties which are suitable in the production of catalysers, polish glass and also as alloying agent. Therefore, a series of praseodymium oxide catalyst was prepared by incipient wetness impregnation method and was calcined at 400oC for 5 hours during screening reaction. The experimental Box-Behnken design was applied for optimizing the parameters in catalytic methanation reaction. The optimum parameters were found to be compatible with the experimental result which showed that Ru/Mn/Pr (5:35:60)/Al2O3 calcined at 800°C with 65% Pr loading and 7 g of catalyst dosage gave 96% of CO2 conversion, determined using FTIR, and yielded about 41% of CH4 at reaction temperature of 400°C. In the stability test, the catalyst’s performance showed an increase and was stable up to 7 hours with 96% of CO2 conversion. X-ray Diffraction (XRD) analysis showed an amorphous structure while Field Emission Scanning Electron Microscope (FESEM) illustrated the presence of small and dispersed particles with undefined shape covering the catalyst surface. EDX analysis revealed that when calcination temperature increased, the mass ratio of Ru increased. Meanwhile Nitrogen Adsorption (NA) analysis revealed that Ru/Mn/Pr (5:35:60)/Al2O3 catalyst attained surface area of 134.39 m2/g

Characteristic of praseodymium oxide doped manganese/ruthenium catalyst in methanation: effect calcination temperature

Methanation reaction using carbon dioxide gas is one of favorable green technology to form methane gas by converting carbon dioxide in the presence of hydrogen. This technology needs the catalyst to achieve a higher catalytic activity. Therefore, a catalyst of Ru/Mn/Pr (5:30:65)/Al2O3 (RMP, 5:30:60) was prepared via wetness impregnation method and investigated on the effect of calcination temperatures with respect to catalytic performance using FTIR analysis. The RMP (5:30:60) catalyst calcined at 800oC was chosen as an excel catalyst with 96.9% of CO2 conversion and 45.1% CH4 formation at 350oC reaction temperature. From the EDX mapping, it can be observed that the distribution of all element is homogeneous at 800oC except Ru, O and Al at 900oC and 1000oC calcination temperature. The image from FESEM also shows the presence of some crystal shape on the catalyst surface. From the FTIR analysis, the peaks stretching and bending mode of O-H bonding decreased when the calcination temperature increased

Effectiveness of Ru/Mg/Ce supported on alumina catalyst for direct conversion of syngas to methane: Tailoring activity and physicochemical studies

The century of urbanisation and industrialisation had a great impact on the environment due to the rapid growth of the flue gas sectors. Thus, green technology is enforced to convert carbon dioxide (CO2) gas into methane (CH4) gas as an alternative fuel in electricity generation, particularly coal and natural gas sources. Cerium (Ce) was recognised as one of the most basic and unique redox characteristics utilised in the promising methanation reaction among catalysts used. The trimetallic catalyst used in this work was prepared with Ce as the based catalyst and ruthenium/magnesium (Ru/Mg) as the impregnated metal. Response surface methodology projected the CO2 conversion to be less than 0.3% of the experimental value of 78.82% using the indicated parameters of 593 °C calcination temperature and 61 wt.% ratios. Ru/Mg/Ce/Al2O3 catalyst with 60 wt.% of Ce loading calcined at 600 °C produced 58.08% of CH4. The characterisation results revealed that CeO2, Mg(Al2O4), and RuO2 species were the active species for CO2 methanation selectivity, as observed in XRD and XPS analyses. The mesoporous structure and particle agglomeration resulted in a surface area of 147 m2/g

Optimization and physicochemical studies of alumina supported samarium oxide based catalysts using artificial neural network in methanation reaction

Developed countries are increasing their demand for natural gas as it is an industrial requirement for fuel transportation. Most of modern society relies heavily on vehicles. However, the presence of CO2 gas has led to the categorization of sour natural gas which reduces the quality and price of natural gas. Therefore, the catalytic methanation technique was applied to convert carbon dioxide (CO2) to methane (CH4) gas and reduce the emissions of CO2 within the environment. In this study, samarium oxide supported on alumina doped with ruthenium and manganese was synthesized via wet impregnation. X-ray diffraction (XRD) analysis revealed samarium oxide, Sm2O3 and manganese oxide, MnO2 as an active species. The reduction temperature for active species was at a low reaction temperature, 268.2oC with medium basicity site as in Temperature Programme Reduction (TPR) and Temperature Programme Desorption (TPD) analyses. Field Emission Scanning Electron Microscopy (FESEM) analysis showed an agglomeration of particle size. The characterised potential catalyst of Ru/Mn/Sm (5:35:60)/Al2O3 (RMS 5:35:60) calcined at 1,000oC revealed 100% conversion of CO2 with 68.87% CH4 formation at the reaction temperature of 400oC. These results were verified by artificial neural network (ANN) with validation R2 of 0.99 indicating all modelling data are acceptable

Investigation of active species in methanation reaction over cerium based loading

A series of cerium oxide based catalyst has been studied by various cerium loadings that calcined at 1000oC using wet impregnation method. The potential Ru/Mn/Ce (5:35:60) /Al2O3 catalyst calcined at 1000oC was characterized using XRD, XPS, and BET analyses. As could be observed from the XRD analysis, at Ce ratio of 55% and 65%, both revealed the presence of RuO2 with tetragonal phase and intense, sharper peaks indicating to high crystallinity and in line with lower surface area, 50.95 m2/g in BET analysis. Meanwhile, CeO2 (cubic phase) and MnO2 (tetragonal phase) were also observed for 55%, 60%, and 65%, respectively. However, the presence of Al2O3 with rhombohedral phase at 55% and 65% was revealed as an inhibitor which decreased the CO2 conversion. The presence of active species on Ru/Mn/Ce (5:35:60) /Al2O3 catalyst has been confirmed using XPS analysis with the deconvolation peaks belonged to Ce4+ with the formation of CeO2 compound and Mn4+ for MnO2. The product formed in catalytic methanation was proposed to be H2O and CH3OH from GC and HPLC analysis

Catalytic transesterification of coconut oil in biodiesel production: A review

Biodiesel is one of the renewable energy (RE) sources that has received much interest due to its promising properties. Recently, the use of coconut oil as biodiesel has caught the attention of many researchers. As a result, this paper presents a comprehensive overview of the current catalysts used to produce coconut oil biodiesel via the transesterification method

Design and optimization of lanthanide oxides based catalysts for carbon dioxide methanation

The Malaysian crude natural gas contains toxic and acidic gases such as carbon dioxide, CO2 (20-30%), and hydrogen sulfide, H2S (0-1%), therefore it should be treated. The current gases treatment process including chemical solvents, adsorption process using hybrid solvents and membrane failed to meet the processing requirement. Instead, catalysts used for the CO2 methanation have been extensively studied and high potential towards converting CO2 gas to methane. In this research, a series of lanthanide oxide based catalysts supported on alumina and doped with manganese and ruthenium were prepared by wetness impregnation method. The lower performance of monometallic and bimetallic oxide catalysts have steered the exploration of trimetallic oxide catalyst. The potential trimetallic oxide catalysts were calcined at 400oC, 700oC, and 1000oC for 5 hours separately. In-home-built micro reactor, Fourier transform infrared (FTIR) spectroscopy and gas chromatography analysis (GC) were used to study the catalytic performance by determining the percentage of CO2 conversion and also the percentage of CH4 formation. From the catalytic screening, it was found that the catalysts with Ru/Mn/Ce (5:35:60)/Al2O3 calcined at 700oC, and Ru/Mn/Sm (5:35:60)/Al2O3 calcined at 1000oC achieved 100% CO2 conversion, Ru/Mn/Pr (5:30:65)/Al2O3 calcined at 800oC achieved 96% CO2 conversion were potential catalysts. The active species in the methanation reaction for each catalyst were MnO2, and RuO2 and CeO2 or Sm2O3 or Pr2O3 respectively. Using two series furnace reactors, all three potential catalysts showed the increasing of CH4 formation. For optimization, the parameters studied were calcination temperatures, based loadings, and catalyst dosage. The optimization was done by using response surface methodology (RSM) with Box-Behnken design which showed the significant parameters and optimum result of cerium with calcination temperature of 697.47oC, based metal ratio of 60.38% and catalyst dosage 6.94 g as suggested by RSM. This result was tested and verified experimentally with difference of only 1%. X-rays diffraction analysis showed that the catalysts imposed an amorphous phase, while field emission scanning electron microscopy illustrated the catalyst surface was covered with small and dispersed particles with undefined shape. From electron dispersive X-rays analysis revealed that there were a reduction of Ru in the used catalyst compared to the fresh catalyst for each potential catalysts. Nitrogen gas adsorption showed that the catalysts were mesoporous structure with type H3 hysteresis loop and Type IV isotherm. Electron spin resonance spectrum showed a free electron interaction due to the presence of the peak for each potential catalyst. Temperature programmed reduction analysis of Ru/Mn/Ce (5:35:60)/Al2O3 catalyst showed more reducible species compared to catalysts containing Sm and Pr due to the presences of more reduce species at lower reduction temperature. The postulated methanation reaction follows the Langmuir Hinselwood mechanism which initially involves adsorption of CO2 and H2 gases on the catalyst surface. For Ru/Mn/Ce (5:35:60)/Al2O3 and Ru/Mn/Sm (5:35:60)/Al2O3 catalysts the product obtained were CH4, CH3OH and H2O. Meanwhile, for Ru/Mn/Pr (5:30:65)/Al2O3 catalyst only CH4 and H2O were observed as a products of the reaction. Lastly, the spent catalysts were successfully regenerated by running under O2 flow at 100oC for 1 hour

Methanation reaction over samarium oxide based catalysts

Malaysia produces an acidic crude natural gas which contains 23% of CO2 and 95 % of CO2 conversion at 300 oC reaction temperature and yielded about 93.46 % of CH4 at reaction temperature of 400 °C. XRD analysis showed the potential catalysts are an amorphous phase, while FESEM analysis illustrated the surface of the catalysts were covered with small and dispersed spherical particles. EDX analysis revealed that there were 0.3 % reduction of Ru in the Ru/Mn/Sm (5:35:60)/Al2O3 ofused catalysts compared to fresh catalysts. Meanwhile NA analysis showed that Ru/Mn/Sm (5:35:60)/Al2O3 catalystattained surface area of 47.38 m2/g

Physicochemical study of supported cobalt-lanthanum oxide-based catalysts for Co-2/H-2 methanation reaction

A series of Ru/Co/La/Al2O3 supported on alumina (Al2O3) were prepared to investigate its catalytic study which aimed the performance of the catalyst. The potential catalysts were subjected to calcination at various temperatures in order to investigate the physicochemical properties of the oxides affected by the parameter. The samples were then characterized by X-ray diffraction (XRD), field emission scanning electron microscopy–energy dispersive X-ray (FESEM–EDX), and Brunauer, Emmett, and Teller analyses. It was found that phase evolutions took place after subjected to calcination at various temperatures. However, the calcination temperatures did not significantly affect the morphology, surface area, and particle size of the catalysts. The FESEM analysis revealed that fresh nanosized Ru/Co/La(5:35:60)/Al2O3 catalyst was obtained with agglomeration and not homogenously dispersed. In the reduction process, smaller particles were found to be more difficult to be reduced than the larger particles. From the EDX, the expected elements were observed, and aluminum (Al) was found to be the most dominant. Besides that, the XRD analysis performed on Ru/Co/La(5:35:60)/Al2O3 catalyst at calcination temperatures of 900, 1,000, and 1,100 °C showed very low degree of crystallinity and were dominated by Al2O3 as the support

Insight mechanistic study of samarium oxide based catalyst in methanation reaction

An understanding of the mechanism of chemical reactions is needed to optimize the reaction process and improve performance. The adsorption of reactant molecules, formation of reaction intermediates, and finally the distribution of products depend on the composition and surface structure of the catalyst. This research work deployed Fourier transform infrared (FTIR), high performance liquid chromatography (HPLC), and gas chromatography (GC) to identify the mechanism of Sm/Mn/Ru (60:35:5)/Al2O3 catalyst. The envisioned methanation reaction initially follows the Langmuir Hinselwood mechanism with the adsorption of CO2 and H2 gases on the catalyst surface. From the gaseous product, only methane peak was observed. Meanwhile, from the liquid product, methanol peak is observed at retention time 20 mins which accordance with standard methanol. Therefore, the final products acquired from the methanation reaction of Sm/Mn/Ru (60:35:5)/Al2O3 catalyst are CH4, CH3OH and H2O