15 Search Results

Palm oil, one of the most widely used vegetable oils, offers significant potential as a sustainable feedstock for biofuel production. This study explores the deoxygenation of palm oil using glycerol as a hydrogen donor, with nickel-molybdenum (NiMo) catalysts supported on commercial alumina (Al₂O₃), and zeolite (HZSM-5) comparing with self-prepared zirconia (ZrO₂). The catalysts were synthesized via incipient wetness impregnation and evaluated for their performance in biofuel production. NiMo/Al₂O₃ exhibited the lowest oxygen removal efficiency (68.5 %), while NiMo/HZSM-5 achieved a higher oxygen removal (74.3 %) but also demonstrated the highest coke formation. The type of support material influenced the resultingmore » biofuel range, with NiMo/HZSM-5 and NiMo/ZrO₂ favoring jet fuel production, whereas NiMo/Al₂O₃ was more suitable for diesel production. Notably, NiMo/ZrO₂ exhibited the highest performance in palm oil deoxygenation while minimizing coke formation. These findings highlight NiMo/ZrO₂ as a promising catalyst for efficient and stable biofuel production, with the support material significantly influencing product yield and fuel quality.« less

Biofuels offer a promising solution in the fight against climate change. With a global increase in waste cooking oil, this research investigated the production of bio-hydrogenated diesel (BHD) from waste cooking oil, using ethanol as a hydrogen donor in the deoxygenation process. A hydrolyzed waste cooking oil model compound served as the feedstock, and the deoxygenation was performed at 300–400 °C. The catalysts used in the experiments were 2.6 wt% Ni and 7.8 wt% Mo (2.6Ni-7.8Mo) and 10 wt% Ni and 5 wt% Mo (10Ni-5Mo) on γ-Al₂O₃. The results showed that ethanol is an effective hydrogen donor for biofuel productionmore » without the need for external hydrogen at an elevated pressure. The increasing temperature enhanced the free fatty acid (FFA) conversion and n-alkane selectivity in the oil product, with the highest FFA conversion and alkane selectivity of 100 % and 46 %, respectively, observed at 400 °C for the sulfided 10Ni-5Mo catalyst. On the other hand, 2.6Ni-7.8Mo offers 100 % FFA conversion with a lower n-alkane selectivity of 35 % at identical temperatures. The total acid number (TAN) of the oil products decreased from 174.03 mg KOH/g of feedstock to 9.43 and 8.67 mg KOH/g with the sulfided 2.6Ni-7.8Mo and 10Ni-5Mo catalysts, respectively. Both the catalysts achieved similar heating values (~43 MJ/kg) at 400 °C. This is a significant improvement to the HHV of the feedstock, which was 36.02 MJ/kg. Additionally, aromatic compounds, mainly BTXE (benzene, toluene, xylene, and ethylbenzene), were also produced. Compared to glycerol as a hydrogen donor, ethanol more effectively increased n-alkane selectivity due to its higher effective hydrogen-to-carbon ratio (H/C_eff). Conversely, glycerol was more advantageous for achieving greater selectivity towards BTXE compounds due to its lower H/C_eff, which potentially leads to coke formation. Since aromatic compounds are intermediates in coke production, glycerol provides higher aromatic selectivity than ethanol. Finally, this study presents an alternative pathway for producing diesel fuel from waste cooking oil using ethanol as a hydrogen donor.« less

The growing demand for renewable energy has generated interest in biofuels as alternatives to fossil fuels. Second-generation biofuels, derived from deoxygenating fats and oils, have garnered a higher level of interest from industry and academia due to their potential for direct replacement of diesel and jet fuels. Palm oil, mostly cultivated in Thailand and composed of C16 and C18 fatty acids, is a primary feedstock sought for biofuel production. Palm oil deoxygenation contains several pathways that may or may not require hydrogen gas. This study aimed to produce biofuels in different fuel ranges, such as gasoline, jet fuel, and diesel,more » through palm oil deoxygenation using glycerol as a hydrogen source. Glycerol, a low-value byproduct, was used as a hydrogen donor, whereas nickel-molybdenum-supported catalysts were chosen for their high efficiency in deoxygenation and cost-effectiveness. The study investigated the impact of reaction time, temperature, and catalyst activation method on palm oil deoxygenation. Catalyst characterization methods, including XRD, SEM, TEM, XPS, FTIR, TGA, and nitrogen-sorption, were employed to understand the role of catalysts’ activity during palm oil upgrading. Findings indicated that alkane hydrocarbons are the major components in liquid products. The presence of excess hydrogen in post reaction gaseous phase proves the hydrogen donation capability of glycerol. Increased reaction time and temperature facilitated the removal of oxygen from palm oil. Nickel-molybdenum on zirconia activated by sulfidation demonstrated higher stability than by reduction activation.« less

Grindelia squarrosa (curlycup gumweed) biomass possesses unique biochemistry, cell wall composition, and leaf architecture tailored for prolific growth in arid and semiarid climates. Most notably, this plant has developed high levels of extractable resins that have high effective H/C_eff ratios ((mol H - 2 x mol O)/mol C), which is hypothesized to lead to low coke formation during catalytic fast pyrolysis (CFP) over the ZSM-5 catalyst. In microscale experiments with high ZSM-5 loadings (biomass-to-catalyst mass ratio (B/C) ~ 0.1), in situ CFP generated high yields of aromatic hydrocarbons (30% carbon yield) while ex situ CFP favored aliphatic hydrocarbons (25% carbonmore » yield). The difference between the two configurations was attributed to the constant catalyst temperature during ex situ CFP. Deactivation leading to partially deoxygenated vapor products occurred rapidly until B/C ≤ 0.5 by the adsorption of organic species blocking access to acid sites inside the micropores of the catalyst. This was followed by more gradual deactivation leading to primary vapor breakthrough, which we attribute to coke formation on acid sites on the external surface of ZSM-5 crystallites. Noncatalytic fast pyrolysis of Grindelia in a bench scale reactor produced oils with oxygen content (18 wt % on dry basis) and carbon yield (33%) comparable to those of CFP of woody biomass. The CFP of Grindelia further reduced the oxygen content to 7 wt % for in situ CFP and 4 wt % for ex situ CFP at B/C of 2-3. The good deoxygenation was attributed to a combination of a high H/C_eff ratio and overall better quality of the pyrolysis vapors that were passed over the ZSM-5 catalyst. The high inorganic content of the Grindelia likely catalyzed pyrolysis to remove oxygenated coke precursors. This integrated CFP study demonstrated that Grindelia could be an important feedstock for generating stabilized noncatalytic and CFP oils for downstream processing into fuels and/or extraction of high-value chemicals. The preprocessing of this feedstock will be required to remove inorganics, which cause an irreversible deactivation of ZSM-5.« less

Gasification is one of the methods of generating biopower or biofuels from biomass waste. In this study, a benchscale fluidized bed reactor was used for biomass air and air-steam gasification. Gasification was performed under constant operating conditions (~780 °C, equivalence ratio = ~0.32) to investigate the effect of biomass (switchgrass, pine residues) and bed materials (sand, CaO+ sand, Al₂O₃, and CaO + Al₂O₃). All gasification products, such as synthesis gas (syngas), contaminant gases, tar, and biochar (solid) were comprehensively analyzed. The composition of biomass significantly impacted CO and H₂ yield from volatile combustible matter and fixed carbon. Further, the presencemore » of CaO made the condition favorable for the water-gas shift (WGS) reaction combined with the CO₂ carbonation reaction, which increased H₂ concentration. Additional steam with CaO increased H₂ concentration closer to 50% (N₂ free condition) through the combination reactions of steam hydrocarbon reforming and WGS by producing 44 g_H2/kg_dry biomass and 143 g_CO/kg_{dry biomass}. The usage of steam reduced the overall yield of contaminant gases, whereas the usage of CaO or Al₂O₃ decreased the amount of gasification tar by approximately 5.8–6.5 g_tar/kg_{dry biomass}. In conclusion, this study can provide valuable experimental data for biomass waste to produce better quality syngas.« less

Polylactic acid (PLA) and organosolv lignin were mixed at different ratios and extruded to obtain PLA-lignin composite filaments. PLA was replaced with lignin up to 20 wt%. Two plasticizers (polyethylene glycol (PEG) 2000 and struktol TR451) were added in varying concentrations to enhance the properties of PLA_L20 (20% lignin in PLA) composite filaments. Furthermore, the effect of lignin in PLA, and PEG, and struktol in PLA_L20 composites was investigated via tensile test, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, Fourier transform infrared spectroscopy of the filaments, and dynamic mechanical analysis of 3D printed samples. A 2 wt% PEG wasmore » able to enhance both tensile stress and elongation at maximum load of PLA_L20 composite by 19% and 35%, respectively, whereas struktol TR451 was able to improve elongation at maximum load by 24%.« less

A pilot scale pressurized (50 psi) fluidized bed gasification was performed to investigate the effects of the jet/ grid air ratio (5:95–90:10) and equivalence ratio (ER = 0.23–0.45) on the gasification products such as syngas, tar, contaminant gas, and biochar. There was a noticeable effect of the jet/grid ratios on the syngas concentration. An increase in CO, CH₄, and C₂ gases was obtained at the condition closer to jet/grid = 50:50, whereas a higher jet/grid ratio favored water–gas shift reaction by increasing CO₂ and H₂ gases under the pressurized condition. The highest lower heating value (LHV) of 7.7 MJ/Nm³ wasmore » obtained at the lowest ER = 0.23. Both the jet/grid ratio and ER were important parameters in determining the H₂ concentration. The cold gasification and carbon conversion efficiencies were obtained as high as 66% and 94%, respectively. Also, higher temperature and ER promoted a reduction in contaminant gases as well as tar yield. Tar product yield was also reduced significantly after a wet scrubber, and the tar consisted of chemicals of a carbon number less than 13 (≤C₁₂). Here, the gasification biochar was also analyzed and showed an effective carbon sequestration property with a relatively higher surface area (105 m²/g). Furthermore, computational fluid dynamics simulation was performed to determine the effects of different jet/grid air ratio and pressure conditions on the hydrodynamics in the fluidized bed reactor.« less