Ni-BTC metal-organic framework loaded on MCM-41 to promote hydrodeoxygenation and hydrocracking in jet biofuel production

To improve catalytic performance of metal active sites in hydrodeoxygenation and hydrocracking conversion of methyl palmitate into high-quality jet biofuel, Ni-1,3,5-benzenetricarboxylate (Ni-BTC) metal-organic framework loaded on MCM-41(Mobil Composition of Matter No. 41) was prepared to enhance the accessibility of Ni active sites, facilitating hydrodeoxygenation to increase alkane yield with suitable arene content. The distance (0.98 nm) between Ni active sites within Ni-BTC structure, which was much larger than that (0.20 nm) within Ni nanoparticles, enabled methyl palmitate with maximum molecule width of 0.68 nm to go through Ni-BTC crystalline plane and get access to Ni active sites more easily. Ni-BTC nanosheets newly assembled in pore channels of MCM-41 were beneficial to effectively screen chain molecules of alkane products. With the largest BET surface area of 1014.2 m²/g, the Ni-BTC@MCM-41 catalyst with 2.5 wt% nickel (2.5Ni-BTC@MCM-41) reduced the nickel metal consumption by 75% comparing to nickel nanoparticle loading (10Ni@MCM-41), but achieved the best catalytic performances through hydrodeoxygenation on Ni active sites and hydrocracking on -SiOH acid sites. The alkane yield increased from 23.3% to 33.9%, while arene yield reduced from 22.4% to 6.5% in jet biofuel products. This resulted in an overall jet biofuel yield of 53.2% with uniform distribution along carbon numbers. The higher heating value of jet biofuel products thus increased to a peak of 45.90 MJ/kg.     

Assessment of basic properties and thermal analysis of hybrid biofuel blend

Among the alternative fuels, vegetable oil is seen as a potential source of energy due to its readily available variety of sources and its certain physical properties that are comparable to those of diesel fuels. However, higher contents of triglyceride in vegetable oil contribute to higher viscosity and density that is affecting the inferior engine performance and emissions. The key properties, such as viscosity, density, and calorific value (CV), have a significant effect on fuel atomization, fuel combustion, and exhaust emissions. In this study, refined palm oil (RPO) was blended with a newly introduced novel biofuel, Melaleuca cajuputi oil (MCO), in order to reduce the viscosity and density and enhance blend properties. This blend is analyzed and compared with RPO–diesel and RPO–ethanol blends in terms of viscosity, CV, and density. These hybrid binary biofuel (HBB) blends were prepared on the volumetric basis of 10%, 20%, 30%, and 50% of MCO, ethanol, and diesel with RPO. The basic fuel properties and the correlation of temperature–viscosity–blend ratio were analyzed. The results showed that the MCO has comparable key properties to those of diesel fuels. The viscosity and density of HBB decrease as the fraction of MCO/ethanol/diesel increases in the blend. The higher the fraction of MCO/diesel in the blend, the higher is the CV observed. Notably, the viscosity of neat RPO and its blends is strongly influenced by temperature variations. The combination of blend technique and preheating had a substantial effect in reducing the viscosity and density of the HBB. Remarkably, the blend of MCO–RPO has the potential to highly considered as a new source of biofuel.     

Catalytic fast pyrolysis of pressure-sensitive adhesives wastes using Py-GC/MS

Catalytic fast pyrolysis of pressure-sensitive adhesives (PSAs) wastes was tested by Py-GC/MS for potential preparation of fuels from PSAs wastes. The effects of ZSM-5 and the ash from the combustion of PSAs on the compositions of the condensable and incondensable products were investigated. It was found that the oxygen content in the condensable product is reduced with more generated aromatics over ZSM-5. Ash presented positive effects on the upgrading of incondensable products with a favorable H₂/CO ratio of 2 and a higher caloric value. Reaction routes of chain aliphaticcompounds under the catalysis of ZSM-5 and ash were respectively proposed.     

In-situ catalytic upgrading of biomass-derived vapors using HZSM-5 and MCM-41: Effects of mixing ratios on bio-oil preparation

In this paper, two molecular sieves with different pore sizes, namely HZSM-5 and MCM-41, were mixed using different ratios and used in the in-situ catalytic pyrolysis of rape straw. The effects of different HZSM -5 and MCM -41 mixing ratios on the quality of the bio-oil were studied by physicochemical properties, product yields and compositions. Moreover, Brunauer-Emmett-Teller (BET) catalyst analysis was performed. The results showed that the liquid yield and organic phase decreased first and then increased, whereas the gas yield showed an opposite trend. The density, O/C and kinematic viscosity of the bio-oil organic phase decreased first then increased, whereas the H/C, pH values and higher heating values initially increased, then declined. The oxygen content, H/C, O/C, kinematic viscosity, density, higher heating value and pH value of the bio-oil organic phase obtained at 1:1 mixed ratio were 12.81%, 1.701, 0.126, 5.06 mm²/s, 0.94 g/cm³, 34.31 MJ/kg and 5.41, respectively. The organic phase included numerous organic compounds, such as carboxylic acids, aldehydes, ketones, hydrocarbons, alcohols, ethers and esters. The hydrocarbon content in the bio-oil organic phase gradually increased and the carbonyl groups content gradually decreased as the MCM-41 content increased from 0 to 50%. In contrast, the hydrocarbon content gradually decreased and the carbonyl groups content gradually increased as the MCM-41 content increased from 50% to 100%. The hydrocarbon and carbonyl groups contents were 53.83% and 6.35%, respectively, at the MCM-41 content of 50%. The mixed catalyst activity increased with the increase in MCM-41 content (up to 50%), and tended to be stable once the MCM-41 contents surpassed 50%.     

Pyrolysis of soybean oil with H-ZSM5 (Proton-exchange of Zeolite Socony Mobil #5) and MCM41 (Mobil Composition of Matter No. 41) catalysts in a fixed-bed reactor

Soybean oil was pyrolyzed with various catalysts in a fixed-bed reactor under nitrogen flow at 420 and 450 °C. The H-ZSM5 catalysts (molar ratio SiO₂/Al₂O₃ = 28, 40, and 180) and 2 wt% (Ga, Al or Cu) impregnated MCM41 catalysts were used in order to investigate the effect of catalysts during the pyrolysis process. The gas products in all experiments were mainly methane, ethane and propylene. The liquid products in the presence of H-ZSM5 catalysts were mainly aromatic components while those with metal/MCM41 catalysts were a mixture of alkanes, alkenes, alkadienes, aromatic and carboxylic acids. The highest coke yield of 4.4 wt% was obtained with Ga/MCM41 catalyst at the pyrolysis temperature of 420 °C. The effect of catalysts on product yield and composition was systematically investigated.     

Hydrogen production by aqueous phase reforming of phenol derived from lignin pyrolysis over NiCe/ZSM-5 catalysts

Incipient wetness impregnation was used to synthesized the NiCe/ZSM-5 catalysts with different ratio of Ni:Ce, and CeO₂ was added as an assistant in the synthesis process. The physicochemical properties of the prepared catalysts were characterized by Transmission electron microscopy (TEM), X-ray diffraction (XRD), N₂-Sorption, H₂ temperature programmed reduction (H₂-TPR), X-ray photoelectron spectroscopy (XPS), Fourier Transform infrared Spectroscopy (FTIR) and ultraviolet–visible diffuse reflectance spectra (UV–Vis DR). The catalytic activities of the obtained catalysts were tested by using the reaction of aqueous phase reforming of phenol to produce hydrogen. Adding appropriate doze of Ce to the catalysts can increase the dispersion of nickel on the ZSM-5 support. The results showed that hydrogen selectivity was higher over 8Ni8Ce/ZSM-5 than using 8Ni/ZSM-5 as aqueous phase reforming catalysts. The content of carbon monoxide in the products after reaction over different catalysts was very low. However, the dispersion of carbon dioxide and hydrocarbons was significantly different over the two catalysts.     

Optimization of heterogeneous biodiesel production from waste cooking palm oil via response surface methodology

Heterogeneous transesterification of waste cooking palm oil (WCPO) to biodiesel over Sr/ZrO₂ catalyst and the optimization of the process have been investigated. Response surface methodology (RSM) was employed to study the relationships of methanol to oil molar ratio, catalyst loading, reaction time, and reaction temperature on methyl ester yield and free fatty acid conversion. The experiments were designed using central composite by applying 2⁴ full factorial designs with two centre points. Transesterification of WCPO produced 79.7% maximum methyl ester yield at the optimum methanol to oil molar ratio = 29:1, catalyst loading = 2.7 wt%, reaction time = 87 min and reaction temperature = 115.5 °C.     

Effect of metal based additive on performance emission and combustion characteristics of diesel engine fuelled with biodiesel

This study investigates the use of ferric chloride (FeCl₃) as a fuel borne catalyst (FBC) for waste cooking palm oil based biodiesel. The metal based additive was added to biodiesel at a dosage of 20 μmol/L. Experiments were conducted to study the effect of ferric chloride added to biodiesel on performance, emission and combustion characteristics of a direct injection diesel engine operated at a constant speed of 1500 rpm at different operating conditions. The results revealed that the FBC added biodiesel resulted in a decreased brake specific fuel consumption (BSFC) of 8.6% while the brake thermal efficiency increased by 6.3%. FBC added biodiesel showed lower nitric oxide (NO) emission and slightly higher carbon dioxide (CO₂) emission as compared to diesel. Carbon monoxide (CO), total hydrocarbon (THC) and smoke emission of FBC added biodiesel decreased by 52.6%, 26.6% and 6.9% respectively compared to biodiesel without FBC at an optimum operating condition of 280 bar injection pressure and 25.5^o bTDC injection timing. Higher cylinder gas pressure, heat release rate and shorter ignition delay period were observed with FBC added biodiesel at these conditions.