Carbon dioxide reforming of methane over cobalt supported on activated carbon catalysts for syngas production

Carbon dioxide reforming of methane (CDRM) utilizes two major greenhouse gases (GHG) of methane (CH4) and carbon dioxide (CO2) for syngas production. The transformation of GHG satisfies the requirements of synthesis processes and is a great interest for reducing gas emission. In this work, cobalt catalysts were synthesized by wet impregnation method onto oil palm shell activated carbon (OPS‒AC) and zeolite socony mobil-5 (ZSM‒5). The characterizations of supported cobalt catalysts were performed by elemental analysis, Brunauer-Emmett- Teller, thermogravimetric analysis, x-ray diffraction, temperature programmed reduction, temperature programmed desorption, scanning electron microscope, field emission scanning electron microscopy and transmission electron microscopy analysis. In comparison of both supported cobalt catalysts, OPS‒AC supported catalysts exhibited superiority in physical and chemical properties than that of ZSM‒5. Four manipulated parameters of the micro reactor system namely operating pressure, operating temperature, feedstock ratio of CH4/CO2 and gas hourly space velocity (GHSV) were investigated. In catalyst screenings, cobalt 14wt% of OPS‒AC (OPS-AC(14)) gave better catalytic performance than cobalt 14wt% of ZSM‒5 (ZSM‒5 (14)) with 15 % conversion and 60 % yield at 1023 K. The feedstock gases and products of syngas were analyzed by gas chromatography with thermal conductivity detector for yield of hydrogen (H2) and carbon monoxide (CO) and conversion (CH4 and CO2). Then, activity testings of OPS-AC(14) showed high temperature at 1173 K which favoured the conversion (CH4, 15 %; CO2, 12 %) and yield (H2, 80 %; CO, 47 %). However, conversion and yield disfavoured at high pressure of 7 bar and less effect by CH4/CO2 ratio and GHSV. Multi-responses of both yields (H2 and CO) were optimized at 903 °C, 0.88 bar, 1.31 CH4/CO2 and 4488 mL/h.g-catalyst for a global optimum value by desirability function analysis. Kinetics study of CDRM was performed for OPS-AC(14) using a power law, Arrhenius plot and equation. The reaction orders of CH4 and CO2 were 0.92 and 0.88, respectively which are close to the first order. The average activation energy of CO2 was lower (66.0 kJ/mol) than that of CH4 (77.3 kJ/mol). The potential side reactions were graphically plotted using Mathematica

Dry Reforming of Methane Over Oil Palm Shell Activated Carbon and ZSM-5 Supported Cobalt Catalysts

In this study, cobalt supported oil palm shell activated carbon (Co/OPS-AC) and ZSM-5 zeolite (Co/ZSM-5) catalysts have been prepared for dry reforming of methane. Cobalt ratios of 6.0 and 14.0 wt% were deposited via wet impregnation method to the OPS-AC and ZSM-5 catalysts. The catalysts were characterized by XRD, N2 adsorption--desorption isotherms, BET surface area, SEM, FESEM-EDX, TPR-H2, and TPD-NH3. The dry reforming of methane was performed using a micro reactor system under the condition of 10,000 ml/h.g-cat, 3 atm, CH4/CO2 ratio of 1.2:1.0 and temperature range from 923 K to 1023 K. The gaseous products were analyzed by gas chromatography (GC) with thermal conductivity detector (TCD) and further quantified to determine the conversions of CH4 and CO2, and the yields of CO and H2. Experimental results revealed both catalysts exhibited lower conversions of CO2 and CH4 with the increase in temperature from 923 K to 1023 K. The reduced conversions may be due to the formation of carboneous substance on the catalyst known as coking. Comparatively, Co/OPS-AC gave higher conversions of CO2 and CH4 as well as higher yields of H2 and CO as it has a higher surface area than Co/ZSM-5 which subsequently rendered higher activity for the reforming of methane. With the increasing cobalt loadings and reaction temperature, OPS-AC(14) catalyst exhibited improved activity and H2/CO ratio. Based on these results, cobalt supported OPS activated carbon catalyst was suggested to be more effective for CO2 and CH4 conversions

Aqueous extraction of blue dye from butterfly pea flower

Dyes are widely used in industries such as textiles, leather, paper and plastics to colour their final products. In this research, Clitoria Ternatea flower was used as the source of natural dyes. The objective of this study is to determine the optimum condition of extraction natural dye where the parameters for extraction of natural dye are temperature: 30°C, 40°C, 60°C, 70°C and 90°C, solid to liquid ratio: 1:20, 1:30, 1:40, 1:50 and 1:60 and time: 30 min, 40 min, 60 min, 70 min and 90 min with one factor at one time (OFAT). The extraction temperature at 60°C, solid-to-liquid ratio at 1:30 g/ml and extraction time at 60 min contributed to the maximum yield of extraction. The dry weight of Clitoria Ternatea flower also determined. The results showed that with an adequate operating condition, it was possible to reach good yields using a simple extraction process

Methane dry reforming using oil palm shell activated carbon supported cobalt catalyst: Multi-response optimization

Dry reforming of methane with carbon dioxide was investigated using oil palm shell activated carbon (OPS-AC) supported cobalt catalyst. The cobalt loaded OPS-AC catalysts were prepared by wet-impregnation method and characterized using SEM, FESEM, BET, TPR and TPD. Surface morphology of OPS-AC supported cobalt catalysts exhibited higher porosity, surface area and micropore volume with different densities of cobalt particles and support. Furthermore, greater amount of H2 chemisorbed and acidity were observed with increasing cobalt contents. Response surface methodology (RSM) was employed to design the experiments based on factorial central composite design. Catalytic testing was performed using a micro reactor system by varying four variables: temperature, gauge pressure, CH4/ CO2 ratio and gas hourly specific velocity (GHSV). H2 and CO yields were analyzed and quantified by gas chromatography with thermal conductivity detector (TCD). Both responses (H2 and CO) yields were optimized simultaneously using desirability function analysis. Reaction temperature was the most influential variable with high desirability prevalent for both responses. The optimum response values of H2 and CO yields corresponded to 903 °C, 0.88 bar(g), CH4/ CO2 = 1.31 and GHSV = 4,488 mL/h.g-catalyst

Catalytic cracking of castor oil via microwave assisted method

Castor oil extracted from seeds of Ricinus Communis plant has an immense potential being used to yield valuable hydrocarbons with shorter chain length. Castor oil contains chemical structures of heavy hydrocarbons and long chains may undergo a cracking process which are similar to that as in petrochemical industries. However, cracking process requires extremely high temperature and energy input. This research came by with an attempt to reduce waste of energy using both microwave assisted method and modified metal catalyst, Zn/ZSM-5 to provide sufficient energy for cracking process to occur at comparatively low temperature. Wet impregnation method was used for Zn/ZSM-5 catalyst preparation and the experiments were carried out via microwave-assisted method. The microwave effect on the temperature and mass of condensate formed was investigated at three different output powers; 650, 700 and 750 W, under different Zn/ZSM-5 concentrations; 5, 8 and 10 wt% for 1 h. Results showed that cracking of castor oil is feasible at low temperature (<250 ◦C) using modified Zn/ZSM-5 via microwave assisted method. The highest yield of total mass of condensate (5.61%) was obtained from 750 W output power and 10 wt% Zn/ZSM-5 catalyst concentration. In addition, the highest cracking percentage (97.7%) was obtained from 750 W output power and 5 wt% Zn/ZSM-5 catalyst concentration. Valuable cracked compounds such as octane for fuel products and undecylenic acid for pharmaceutical uses were obtained

Thermal Process of Castor and Plant Based Oil

Castor oil is an oil derived from castor seed from a plant Ricinus communis. The versatility of castor oil is highly attributed by 12-hydroxy-9-octadecenoic acid (ricinoleic acid) and its functional group. It is an oil that cannot be consumed by a human. However, castor oil actually can be used to produce many valuable products such as chemicals, paint, and cosmetics due to its unique characteristic which contains a high percentage of ricinoleic acid that helps in producing many valuable products. The utilization of vegetable oils is currently in the highlight of the chemical industry, as they are one of the most important renewable resources due to their universal availability, inherent biodegradability, low price, and eco-friendly. Therefore, the main aim of this paper is to focus on the thermal cracking of castor oil with Zeolite ZSM-5 as the catalyst generates products consisting alcohol, methyl esters and fatty acids which are valuable raw materials for industries. The background, characteristics, composition, properties and industrial application of castor oil have also been discussed. The important properties and various applications of castor oil which can be obtained from toxic seeds have much greater potential than other available vegetable oils

Thermal process of castor and plant based oil

Castor oil is an oil derived from castor seed from a plant Ricinus communis. The versatility of castor oil is highly attributed by 12-hydroxy-9-octadecenoic acid (ricinoleic acid) and its functional group. It is an oil that cannot be consumed by a human. However, castor oil actually can be used to produce many valuable products such as chemicals, paint, and cosmetics due to its unique characteristic which contains a high percentage of ricinoleic acid that helps in producing many valuable products. The utilization of vegetable oils is currently in the highlight of the chemical industry, as they are one of the most important renewable resources due to their universal availability, inherent biodegradability, low price, and eco-friendly. Therefore, the main aim of this paper is to focus on the thermal cracking of castor oil with Zeolite ZSM-5 as the catalyst generates products consisting alcohol, methyl esters and fatty acids which are valuable raw materials for industries. The background, characteristics, composition, properties and industrial application of castor oil have also been discussed. The important properties and various applications of castor oil which can be obtained from toxic seeds have much greater potential than other available vegetable oils

Development of Graphene Oxide/Polyethylene to enhance mechanical properties through melt mixing technique

Graphene Oxide (GO) was added to Low-Density Polyethylene (LDPE) to test the mechanical properties of the compound. Compared to other types of polyethylene, LDPE provides a good balance of mechanical properties and processability, which leads to its being chosen as the research's matrix material. This experiment aims to prepare LDPE/GO through melt mixing technique and analyse mechanical properties of tensile strength/tensile elongation of LDPE/GO composite based on GO concentration (0, 0.5, 1.0 and 1.5 wt%). The compounding of LDPE/GO was blended using a five-stage twin-screw extruder under specific conditions before going through the moulding process at melting temperature. The composites were cut according to ASTM D638 specimen dimension. The tensile properties of LDPE composites were filled separately with different weight fractions of GO at a 50 mm/min rate. It was found that the values of Young's modulus of the composites increased, but the values of the tensile elongation at break decreased with increasing the GO weight fraction. The relatively big interfacial area and excellent interfacial adhesion between the matrix and the GO may be responsible for the composites' reinforcement. This study provided a basis for further development of GO-reinforced LDPE composites with desirable mechanical performance and good damage behaviour

Explosion characteristics assessment of premixed biogas/air mixture in a 20-L spherical vessel

The understanding of biogas explosion characteristics is needed to describe the severity of the explosion. Biogas is a flammable gas and will explode when ignited. This study reports the experimental results on biogas explosion characteristics in a standard 20-L spherical vessel under quiescent conditions using electric spark (10 J) as an ignition source. Computational Fluid Dynamic (CFD) code FLame ACcelaration Simulator (FLACs) was used to simulate the biogas explosion based on the experimental case study. The dependence of explosion characteristics such as explosion pressure (Pmax), rate of pressure rise (dP/dt), and deflagration index (KG), on biogas concentration and carbon dioxide, CO2 composition is demonstrated. The data allow for the evaluation of the potential severity of biogas explosion, which in turn helps engineers design the explosion mitigation and prevention device related to this gas. The experimental data reported from this study concluded that Pmax = 8–8.50 bar, the dP/dt = 100–400 bar/ms and the KG = 32.7–121 bar m/ms were recorded at equivalence ratio, (ER) = 1.2 with CO2 composition in the biogas = 30% vol/vol. It was found that the severity of the biogas explosion increased proportionally with the biogas concentration. On the contrary, the explosive intensity was weakened by increasing the CO2 concentration due to the physical effects of CO2 and thermal instability. This study also recorded that the biogas explosion was categorized under hazard level = St-3 indicating a catastrophic explosion. These data are important for preventing and mitigating the biogas explosion