An Overview of Response Surface Methodology Approach to Optimization of Hydrogen and Syngas Production by Catalytic Reforming of Greenhouse Gases (CH4 and CO2)

Catalytic reforming of Methane (CH4) and carbon dioxide (CO2) is one of the techniques used for the production of hydrogen and syngas. This technique has dual advantages of mitigation of greenhouse gases and production of hydrogen and syngas which are often used as intermediates for the synthesis of valuable chemical products and oxygenates. This study presented an overview of the application of response surface methodology (RSM) in the optimization of hydrogen and syngas production from catalytic reforming of CH4 and CO2. The different catalytic system that has been employed together with the nature of experimental design, input parameters, responses, the optimum conditions and the maximum values of their responses were examined. The future research direction in the application of RSM to optimization of hydrogen and syngas production by catalytic reforming of CH4 and CO2 was recommended

Samarium Promoted Ni/Al2O3 Catalysts for Syngas Production from Glycerol Pyrolysis

The current paper reports on the kinetics of glycerol reforming over the alumina-supported Ni catalyst that was promoted with rare earth elements. The catalysts were synthesized via wet impregnation method with formulations of 3 wt% Sm-20 wt% Ni/77 wt% Al2O3. The characterizations of all the as-synthesized catalysts were carried out, viz.  BET specific surface area measurements, thermogravimetri analysis for temperature-programmed calcination studies, FESEM for surface imaging, XRD to obtain diffraction patterns, XRF for elemental analysis, etc.. Reaction studies were performed in a stainless steel fixed bed reactor with reaction temperatures set at 973, 1023 and 1073 K employing weight hourly space velocity (WHSV) of 4.5×104 mL g-1 h-1. Agilent GC with TCD capillary column was used to analyze gas compositions. Results gathered showed that the BET specific surface area was 2.09 m2.g-1 for the unpromoted Ni catalyst while for the promoted catalysts, was 2.68 m2.g-1. Significantly, the BET results were supported by the FESEM images which showed promoted catalysts exhibit smaller particle size compared to the unpromoted catalyst. It can be deduced that the promoter can increase metal dispersion on alumina support, hence decreasing the size of particles. The TGA analysis consistently showed four peaks which represent water removal at temperature 373-463 K, followed by decomposition of nickel nitrate to produce nickel oxide. From reaction results for Sm promotion showed glycerol conversion, XG of 27% which was 7% higher than unpromoted catalyst. The syngas productions were produced from glycerol decomposition and created H2:CO product ratio which always lower than 2.0. The H2:CO product ratio of 3 wt% Sm promoted Ni/Al2O3 catalyst was 1.70 at reaction temperature of 973 K and glycerol partial pressure of 18 kPa and suitable enough for Fischer-Tropsch synthesis. 

Hydrogen Production From catalytic reforming of greenhouse gases (CO2 and CH4) Over Neodymiun (III) oxide supported Cobalt catalyst

Hydrogen production from CO2 reforming of methane over 20wt%.Co/Nd2O3 has been investigated in a fixed bed stainless steel reactor. The 20wt%.Co/Nd2O3 catalyst was synthesized using wet impregnation method and characterized for thermal stability, textural property, crystallinity, morphology and nature of chemical bonds using techniques such as TGA, XRD, N2 adsorption-desorption, FESEM, EDX and FTIR. The CO2 reforming of methane was performed at feed ratio (CH4:CO2) between 0.1-1 and reaction temperature ranged 973-1023 K. The catalyst displayed good activity towards selectivity and yield of hydrogen as well as CO, a by product. The selectivity and yield of Hydrogen increases with feed ratio and reaction temperature. The 20wt%.Co/Nd2O3 catalyst displayed promising catalytic activity for hydrogen production with the highest yield and selectivity of 32.5% and 17.6% respectively.Keywords: Cobalt; Greenhouse gases; Hydrogen; Reforming;; Neodymium (III)Oxid

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Process Modelling, Thermodynamic Analysis and Optimization of Dry Reforming, Partial Oxidation and Auto-Thermal Methane Reforming for Hydrogen and Syngas Production

In this work, process modelling, thermodynamic analysis and optimization of stand-alone dry and partial oxidation reforming of methane as well as, the auto-thermal reforming processes were investigated. Firstly, flowsheet models were developed for both the stand-alone systems and auto-thermal reforming process using ASPEN HYSYS®. Furthermore, thermodynamic studies were conducted for the stand-alone and auto-thermal reforming processes for temperatures range of 200–1000°C and pressure range of 1–3 bar using Gibbs free energy minimization methods which was also performed using ASPEN HYSYS®. The simulation of the auto-thermal reforming process was also performed at 20 bar to mimic industrial process. Process parameters were optimized in the combined reforming process for hydrogen production using desirability function. The simulation results show that 84.60 kg/h, 62.08 kg/h and 154.7 kg/h of syngas were produced from 144 kg/h, 113 kg/h and 211 kg/h of the gas fed into the Gibbs reactor at CH4/CO2/O2 ratio 1:1:1 for the stand-alone dry reforming, partial oxidation reforming and auto-thermal processes respectively. Equilibrium conversion of CH4, CO2, O2 were thermodynamically favoured between 400 and 800°C with highest conversions of 100%, 95.9% and 86.7% for O2, CO2 and CH4 respectively. Highest yield of 99% for H2 and 40% for CO at 800°C was obtained. The optimum conditions for hydrogen production were obtained at CH4/CO2, CH4/O2 ratios of 0.634, 0.454 and temperature of 800°C respectively. The results obtained in this study corroborate experimental studies conducted on auto-thermal reforming of methane for hydrogen and syngas production

Biorefinery for the Production of Biodiesel, Hydrogen and Synthesis Gas Integrated with CHP from Oil Palm in Malaysia

Malaysia is presently the world’s largest exporter of palm oil with total production of 19.22 million tonnes of crude palm oil (CPO) in 2013. Aside CPO, by-products such as empty fruit bunch (EFB), palm kernel shell (PKS), palm kernel oil (PKO), palm kernel cake (PKC) and pressed palm fibres (PPF) are produced from the palm oil mills. These biomasses can be used as potential feedstock for the production of biofuels, biogas and bioelectricity. One of the ways to fully harness the potentials of these biomasses is by employing the biorefinery concepts where all the products and by-products from oil palma reutilized for production of valuable bio-products. In this study, technological feasibility of biorefinery for the production of biodiesel, hydrogen, Fischer-Tropsch liquids (FTLs) integrated with combined heat and power (CHP) generation was investigated. Flowsheet was designed for each of the processes using Aspen HYSYS® v 8.0. Material balance was performed on a palm oil mill processing 250 tonnes per year of fresh fruit palm (FFP). Results from the material balance shows that 45.1 tonnes of refined bleached deodorized palm oil (RDBPO) and 52.4 tonnes of EFB were available for the production of biodiesel, hydrogen, FTLs and the CHP generation. The annual plant capacity of the biodiesel production is estimated to be 26,331.912 tonnes.The overall energy consumption of the whole process was estimated to be 36.0GJ/h. This energy demand was met with power generated from the CHP which is 792GJ/h leaving a surplus of 756GJ/h that can be sold to the grid.The process modelling and simulation of the biorefinery process shows technological feasibility of producing valuable products from oil palm

Kinetics and Mechanistic Studies of CO-Rich Hydrogen Production by CH4/CO2 Reforming over Praseodymia Supported Cobalt Catalysts

The production of hydrogen and syngas by catalytic methane dry reforming is often accompanied by carbon deposition. In order to mitigate the effect of carbon deposition, it is important to have a full understanding of the elementary steps involve in the methane dry reforming over a given catalyst. This will enable the proper design and optimization of such catalyst to minimize catalyst deactivation by carbon deposition. In this study, the kinetic and mechanistic features of 20 wt%Co/Pr2O3 catalyst in the methane dry reforming reaction has been investigated as a function of CH4 and CO2 partial pressures and reaction temperature. The 20 wt%Co/Pr2O3 catalyst was synthesized by wet impregnation method and characterized for its physicochemical properties by TGA, XRD, N2-physisorption analysis, TEM, FESEM, EDX, H2-TPR, NH3 and CO2. The excellent physicochemical properties of the 20 wt%Co/Pr2O3 catalysts resulted in a high rate of CH4(rCH4) and CO2(rCO2)consumption. The highest values of 3.6 mmol gcat−1 min−1 and 3.2 mmol gcat−1 min−1 were obtained for rCH4 and rCO2, respectively at 50 kPa and 1023 K. The kinetic behavior of the as-synthesized 20 wt%Co/Pr2O3 catalyst in the methane dry reforming reaction was measured in a fixed bed stainless steel reactor at CH4/CO2 partial pressure range of 5–50 kPa and temperature range of 923–1023 K. The data obtained from the kinetic measurement were fitted into seven Langmuir-Hinshelwood (LH) Models. The Model were statistically discriminated using root mean square deviation (rmsd) and coefficient of determination (R2). The statistical analysis revealed that LH kinetic Model 7 (2-step dual site rate determining steps (RDS) involving CH4 activation by metal Co and C gasification by adsorbed CO2 on support site) fits very well the experimental data. The R2 values of 0.962, 0.982, and 0.989 as well as, rmsd values of 0.095 0.038, and 0.035 were obtained at 923, 973, and 1023 K respectively. Activation energies of 61.67 and 32.52 kJ/mol were obtained for the rate of consumptions of CH4 and CO2, an indication that lower energy barrier is required for the activation of CO2 compared to CH4. Based on Model 7, the mechanism of the methane dry reforming reaction over the 20 wt%Co/Pr2O3 catalyst can best be described by 2-step dual site rate determining steps whereby the activation of CH4 by the metal Co resulted in hydrogen and carbon formation. The carbon formed was subsequently gasified by the lattice oxygen released from the activation of the CO2 by the support site

Catalytic Performance of Ceria-supported Cobalt Catalyst for CO-rich Hydrogen Production from Dry Reforming of Methane

Dry reforming of methane was studied over ceria-supported cobalt (20wt%) catalyst prepared via wet-impregnation method. The synthesized catalyst was characterized using thermogravimetric analysis (TGA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), N2 physisorption and Fourier transform infrared spectroscopy (FTIR). The catalytic methane dry reforming was carried out over the 20wt%Co/80wt%CeO2 catalyst in a fixed-bed reactor. The experiment was performed at atmospheric condition with time-on-stream (TOS) of 4 h, reaction temperatures of 923–1023 K, and CH4:CO2 feed ratios of 0.1–1.0. The XRD pattern showed good dispersion of the cobalt metal on the support. This was corroborated by the FESEM-EDX and FTIR spectrum. The N2 physisorption revealed that the BET specific surface area of the calcined catalyst was more than double the ceria support. The conversions of CH4 and CO2, respectively, as well as the H2 and CO yield, were found to increase with reaction temperature and CH4:CO2 feed ratios. The highest conversions for both CO2 and CH4 were 87.6% and 79.5%, respectively, at 1023 K. Moreover, highest yield of 40% was obtained for CO while that of H2 was 37.6%. Syngas ratio of 0.99 was obtained at a feed ratio of 0.9, which has further cemented the suitability of methane dry reforming over ceria-supported cobalt catalyst for production of syngas meant for Fischer–Tropsch synthesis

Production of CO-rich Hydrogen Gas from Methane Dry Reforming over Co/CeO2 Catalyst

Production of CO-rich hydrogen gas from methane dry reforming was investigated over CeO 2-supported Co catalyst. The catalyst was synthesized by wet impregnation and subsequently characterized by field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX), liquid N2 adsorption-desorption, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) for the structure, surface and thermal properties. The catalytic activity test of the Co/CeO2 was investigated between 923-1023 K under reaction conditions in a stainless steel fixed bed reactor. The composition of the products (CO and H 2) from the methane dry reforming reaction was measured by gas chromatography (GC) coupled with thermal conductivity detector (TCD). The effects of feed ratios and reaction temperatures were investigated on the catalytic activity toward product selectivity, yield, and syngas ratio. Significantly, the selectivity and yield of both H2 and CO increases with feed ratio and temperature. However, the catalyst shows higher activity towards CO selectivity. The highest H2 and CO selectivity of 19.56% and 20.95% respectively were obtained at 1023 K while the highest yield of 41.98% and 38.05% were recorded for H2 and CO under the same condition