Free-H2 deoxygenation of Jatropha curcas oil into cleaner diesel-grade biofuel over coconut residue-derived activated carbon catalyst

Diesel-like hydrocarbons were produced by the catalytic deoxygenation (DO) of Jatropha curcas oil (JCO) over novel Agx/AC and Niy-Agx/AC catalysts under an H2-free atmosphere. The AC was synthesized from coconut fibre residues (CFR), where CFR is the by-product from coconut milk extraction and is particularly rich in soft fibres with high mineral content. The Niy-Agx/AC catalyst afforded higher DO activity via the decarboxylation/decarbonylation (deCOx) route than Agx/AC due to the properties of Ni, synergistic interaction of Ni and Ag species, adequate amount of strong acid sites and large number of weak acid sites, which cause extensive C-O cleavage and lead to rich formation of n-(C15+C17) hydrocarbons. The effect of Ag and Ni content were studied within the 5 to 15 wt% range. An optimum Ni and Ag metal content (5 wt%) for deCOx reaction was observed. Excess Ni is not preferable due to a tendency for cracking and Ag-rich containing catalyst weakly enforced triglycerides breaking. The Ni5-Ag5/AC govern exclusively decarbonylation reaction, which corroborates the presence of Ni²⁺ species and a high amount of strong acid sites. Ultimately, Ni5-Ag5/AC in the present study shows excellent chemical stability with consistent five reusability without drastic reduction of hydrocarbon yield (78–95%) and n-(C15+C17) selectivity (82–83%), which indicate favourable application in JCO DO

Catalytic gasification of oil palm frond biomass in supercritical water using MgO supported Ni, Cu and Zn oxides as catalysts for hydrogen production

Non-noble metal supported catalysts such as 20NiO/MgO, 20CuO/MgO and 20ZnO/MgO were catalyzed the gasification of oil palm frond biomass in supercritical water for hydrogen production. All the catalysts are found to be pure with no impurities present. The specific surface area of these catalysts can be arranged in the order of 20NiO/MgO (30.1 m2 g–1) > 20CuO/MgO (16.8 m2 g–1) > 20ZnO/MgO (13.1 m2 g–1). Although catalysts with larger specific surface area are beneficial for catalytic reactions, in this study, the largest specific surface area did not lead to the highest catalytic performance. It is found that the 20ZnO/MgO catalyst (118.1 mmol ml−1) shown the highest H2 yield than the 20CuO/MgO (81.1 mmol ml−1) and 20NiO/MgO (72.7 mmol ml−1) catalysts. In addition, these supported catalysts also shown higher H2 selectivity with reached 83.8%, 84.9% and 87.6% for 20CuO/MgO, 20NiO/MgO and 20ZnO/MgO catalysts. Other factors such as dispersion, basicity and bond strength play more important roles in supercritical water gasification of biomass to produce hydrogen

Production of renewable diesel from Jatropha curcas oil via pyrolytic-deoxygenation over various multi-wall carbon nanotube-based catalysts

Jatropha curcas is a highly toxic plant that produces seed containing viscous oil with productivity (2 ton/ha), it grows in tropical and sub-tropical regions and offer greater adaptability to a wide range of climatic and soil conditions. Its oils have been noted as an important alternative to produce green diesel via deoxygenation reaction. This study, deoxygenation of jatropha curcas oil (JCO) was carried out over NiO–Fe2O3 and NiO–ZnO catalysts that supported onto multi-walled carbon nanotube (MWCNT). It had found that high Fe and Zn dosages were ineffective in deoxygenation and greatest activity was observed on NiO(20) Fe2O3(5)/MWCNT catalyst. Structure-activity correlations revealed that low metal loading, large density of weak + medium acidic sites and strong basic sites play key role in enhancing the catalytic activities and n-(C15+C17) selectivity. Comparing carbon nanostructures and carbon micron size supported NiO-Fe2O3 revealed that green diesel obtained from NiO–Fe2O3/MWCNT catalysed deoxygenation had the highest heating value and the lowest amounts of oxygen content. Thereby, it confirmed the importance of carbon nanostructure as the catalyst support in improving the diesel quality. Considering the high reusability of NiO-Fe2O3/MWCNT (6 consecutive runs) and superior green diesel properties (flash point, cloud properties and cetane index) demonstrated the NiO–Fe2O3/MWCNT catalyst offers great option in producing excellent properties of green diesel for energy sector

Catalytic supercritical water gasification of oil palm frond biomass using nanosized MgO doped Zn catalysts

In this work, nanosized MgO doped Zn catalysts (Mg1-x Znx O; x = 0.05, 0.10, 0.15, 0.20) were catalyzed the supercritical water gasification (SCWG) of oil palm frond (OPF) biomass for hydrogen production. Increased the amount of Zn in the catalyst enlarged the crystallite size, thus, reduced the surface area. Interestingly, all the synthesized catalysts have crystallite sizes of less than 50 nm. In-depth Rietveld refinement analysis revealed that the enlargement of the crystallite size is due to the phenomenon of cell expansion when the smaller Mg2+ ions being replaced by the larger Zn2+ ions during the doping process. Increased the Zn content also improved the basicity properties. Among the synthesized catalysts, the Mg0.80 Zn0.20 O exhibited the highest total gas volume of 213.5 ml g-1 of the biomass with 438.1% of increment in terms of H2 yield. The metal oxide doped materials serve as a new catalyst structure system for the SCWG technology

Structural and catalytic studies of Mg1-xNixO nanomaterials for gasification of biomass in supercritical water for H2-rich syngas production

Nowadays, catalytic supercritical water gasification (SCWG) is undoubtedly used for production of H2-rich syngas from biomass. The present study reported the synthesis and characterisation of Mg1-xNixO (x ¼ 0.05, 0.10, 0.15, 0.20) nanomaterials that were obtained via self-propagating combustion (SPC) method, and catalysed the SCWG for the first time. It had found that increased the nickel (Ni) content in the catalyst reduced the crystallite size, thus, increased the specific surface area, which influenced the catalytic activity. The specific surface area followed the order of Mg0.95Ni0.05O (36.2 m2 g1 ) < Mg0.90Ni0.10O (58.9 m2 g1 ) < Mg0.85Ni0.15O (63.6 m2 g1 ) < Mg0.80Ni0.20O (67.9 m2 g1 ). From the Rietveld refinement, the Ni that was successfully partial substituted in the cubic crystal structure of MgO resulting in a cell contraction which ascribed the reduction of crystallite size. Increased the amount of Ni also narrowed the pore size distribution ranging between 4.17 nm and 6.23 nm, as well as increased the basicity active site up to 5741.0 mmol g1 at medium basic strength. All the synthesised nanocatalysts were catalysed the SCWG of OPF (oil palm frond) biomass. Among them, the mesoporous Mg0.80Ni0.20O nanocatalyst exhibited the highest total gas volume of 193.5 mL g1 with 361.7% increment of H2 yield than that of the non-catalytic reaction

Single-step catalytic deoxygenation-cracking of tung oil to bio-jet fuel over CoW/silica-alumina catalysts

Bifunctional Co-W catalysts with variable Co-W dosages on silica-alumina (SA) were prepared and tested for the catalytic deoxygenation-cracking of tung oil (TO) for the production of jet fuel (n-(C10-C16)) fractions. The CoW/SA catalyst appeared to be most active (hydrocarbon yield = 69%, jet fuel selectivity = 60%) and outperformed the monometallic Co and W analogues. Based on the effect of metal dosage, Co– and W-rich catalysts do not provide a workable approach in enhancing deoxygenation-cracking of the TO for jet fuel production, and overly cracking can be successfully controlled at lower metal dosages (5 wt% Co, 10 wt% W). The CoW/SA reusability study showed a consistent deoxygenation-cracking ability for four runs with hydrocarbon yields within the range of 77–84% and 64–77% jet fuel selectivity. GCMS analysis and physicochemical properties of TO oil fuel (TO-gasoline, TO-jet, TO diesel) confirmed that rich aromatic species in TO-diesel negatively affected the quality of the fuels. TO-fuels with a short chain had better combustion properties than those with a longer chain hydrocarbon. The TO-jet qualities are complied with standard Jet A-1 in accordance to ASTM D1655 and DEF STAN 91–91 specification standards. The TO-jet also exhibited excellent cold properties and superior combustion characteristic than Jet A-1

Progress on Modified Calcium Oxide Derived Waste-Shell Catalysts for Biodiesel Production

The dwindling of global petroleum deposits and worsening environmental issues have triggered researchers to find an alternative energy such as biodiesel. Biodiesel can be produced via transesterification of vegetable oil or animal fat with alcohol in the presence of a catalyst. A heterogeneous catalyst at an economical price has been studied widely for biodiesel production. It was noted that various types of natural waste shell are a potential calcium resource for generation of bio-based CaO, with comparable chemical characteristics, that greatly enhance the transesterification activity. However, CaO catalyzed transesterification is limited in its stability and studies have shown deterioration of catalytic reactivity when the catalyst is reused for several cycles. For this reason, different approaches are reviewed in the present study, which focuses on modification of waste-shell derived CaO based catalyst with the aim of better transesterification reactivity and high reusability of the catalyst for biodiesel production. The catalyst stability and leaching profile of the modified waste shell derived CaO is discussed. In addition, a critical discussion of the structure, composition of the waste shell, mechanism of CaO catalyzed reaction, recent progress in biodiesel reactor systems and challenges in the industrial sector are also included in this review

A promoter effect on hydrodeoxygenation reactions of oleic acid by zeolite beta catalysts

In this study, various metal-modified zeolite beta-based catalysts such as La(10)zeo(90), Co(10)zeo(90), Fe(10)zeo(90), Mg(10)zeo(90), Mn(10)zeo(90) and Zn(10)zeo(90) were investigated in the hydrodeoxygenation (HDO) of oleic acid (OA) to produce renewable diesel. The La(10)zeo(90) catalyst showed a conversion of OA up to 99 % with 83 % C15 and C17 selectivity after the reaction at 350 ◦C for 2 h under 4 MPa H2 pressure. The superior activity of La(10)zeo(90) was attributed to the synergistic interaction between La-Si-Al, a sufficient amount of weak+ medium acid sites and excellent textural properties (large pore diameter). Larger pore diameter of La(10)zeo(90) is highly desirable as it will generate greater diffusion of bulky molecules, thereby improving the accessibility of the reactant and hence excellent catalytic activity. The vacuum distillation was used to purify the crude liquid product (CLP), producing high-quality diesel fractions mainly comprising C14, C15, and C17 fractions

SiO2-rich sugar cane bagasse ash catalyst for transesterification of palm oil

This study demonstrated the performance of the sugarcane bagasse ash (SCBA) impregnated with calcium oxide (CaO) as a novel heterogeneous basic catalyst in biodiesel production. The SCBAwas prepared by calcination for 2 h at 500 to 800 °C and impregnated with CaO loadings (10 to 40 wt.%). The prepared SCBA/CaO catalyst was characterized using Fourier transform infrared spectros-copy (FTIR), scanning electron microscopy(SEM), X-ray diffraction (XRD), temperature programmed desorption of carbon dioxide(TPD-CO2), thermal gravimetric analysis (TGA), X-ray fluorescence (XRF) and Brunauer-Emmett-Teller (BET) surface characteristics. A series of transesterification reactions were conducted to evaluate the performance of the catalysts. As a result, highest FAME yield of 93.8% was obtained by using SCBA600°CCaO (40%) catalyst at 20:1 methanol-to-oil molar ratio, reaction temperature of65 °C, with 6 wt.% catalyst in 3 h. Besides, the catalyst can be reused up to 5 reaction cycles with biodiesel yield of 93.0% and 70.3%at first and fifth cycles, respectively. In this work, it was found that the natural SiO2in the SCBA has a significant role to enhance the catalytic performance and reduce the catalyst’s deactivation drawback by minimizing the leaching of active sites