Gas-phase hydrodeoxygenation of phenol over Zn/SiO2 catalysts: Effects of zinc load, temperature, weight hourly space velocity, and H2 volumetric flow rate

Pourzolfaghar, Hamed; Abnisa, Faisal; Daud, Wan Mohd Ashri Wan; Aroua, Mohamed Kheireddine

doi:10.1016/j.biombioe.2020.105556

Cited by 15 publications

(5 citation statements)

References 44 publications

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“…Owing to the increasing air pollution levels and decreasing supplies of fossil fuels, bio-oil is considered a promising chemical raw material and liquid fuel. [ 1 , 2 , 3 ]. However, the bio-oils produced by liquefaction or fast pyrolysis have very high oxygen contents (up to 50 wt %), which not only decrease energy density to a value lower than that of petroleum fuel by a factor of two (17 kJ/kg versus 40 kJ/kg), but also result in high viscosity, low pH values, and poor chemical stability.…”

Section: Introductionmentioning

confidence: 99%

Effects of Crystallite Sizes of Pt/HZSM-5 Zeolite Catalysts on the Hydrodeoxygenation of Guaiacol

et al. 2020

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Herein, Pt/HZSM-5 zeolite catalysts with different crystallite sizes ranging from nanosheet (~2 nm) to bulk crystals (~1.5 μm) have been prepared for the hydrodeoxygenation of guaiacol, and their effects on the reaction pathway and product selectivity were explored. HZSM-5 zeolites prepared by seeding (Pt/Z-40: ~40 nm) or templating (Pt/NS-2: ~2 nm) fabricated intra-crystalline mesopores and thus enhanced the reaction rate by promoting the diffusion of various molecules, especially the bulky ones such as guaiacol and 2-methoxycyclohexanol, leading to a higher cyclohexane selectivity of up to 80 wt % (both for Pt/Z-40 and Pt/NS-2) compared to 70 wt % for bulky HZSM-5 (Pt/CZ: ~1.5 μm) at 250 °C and 120 min. Furthermore, decreased crystallite sizes more effectively promoted the dispersion of Pt particles than bulky HZSM-5 (Pt/Z-400: ~400 nm and Pt/CZ). The relatively low distance between Pt and acidic sites on the Pt/Z-40 catalyst enhanced the metal/support interaction and induced the reaction between the guaiacol molecules adsorbed on the acidic sites and the metal-activated hydrogen species, which was found more favorable for deoxygenation than for hydrogenation of oxygen-containing molecules. In addition, Pt/NS-2 catalyst with a highly exposed surface facilitated more diverse reaction pathways such as alkyl transfer and isomerization.

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Section: Introductionmentioning

confidence: 99%

Effects of Crystallite Sizes of Pt/HZSM-5 Zeolite Catalysts on the Hydrodeoxygenation of Guaiacol

et al. 2020

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“…By elevating the zinc metal loading of the catalysts, the total conversion increased, and the highest conversion efficiency was achieved with 3% doping of the active site. In a separate study [42], we observed that a loading of 4% of the active metal (Zn) on the support surface (SiO 2 ) resulted in a slight reduction in the HDO conversion efficiency. The main reason was found to be the occupation of the support surface pores by zinc metal.…”

Section: Reactivitymentioning

confidence: 88%

“…Using the model compounds, one can attain enough data regarding the mechanism and reaction networks of the process. Phenol and its derivatives are known as the most refractory compound in the bio-oil and, hence, it has been selected as the model compound in this investigation [42].…”

Section: Introductionmentioning

confidence: 99%

Catalyst Characteristics and Performance of Silica-Supported Zinc for Hydrodeoxygenation of Phenol

et al. 2020

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The present investigation aimed to study the physicochemical characteristics of supported catalysts comprising various percentages of zinc dispersed over SiO2. The physiochemical properties of these catalysts were surveyed by N2 physisorption (BET), thermogravimetry analysis (TGA), H2 temperature-programmed reduction, field-emission scanning electron microscopy (FESEM), inductively coupled plasma-optical emission spectrometry (ICP-OES), and NH3 temperature-programmed desorption (NH3-TPD). In addition, to examine the activity and performance of the catalysts for the hydrodeoxygenation (HDO) of the bio-oil oxygenated compounds, the experimental reaction runs, as well as stability and durability tests, were performed using 3% Zn/SiO2 as the catalyst. Characterization of silica-supported zinc catalysts revealed an even dispersion of the active site over the support in the various dopings of the zinc. The acidity of the calcinated catalysts elevated clearly up to 0.481 mmol/g. Moreover, characteristic outcomes indicate that elevating the doping of zinc metal led to interaction and substitution of proton sites on the SiO2 surface that finally resulted in an increase in the desorption temperature peak. The experiments were performed at temperature 500 °C, pressure 1 atm; weight hourly space velocity (WHSV) 0.32 (h−1); feed flow rate 0.5 (mL/min); and hydrogen flow rate 150 (mL/min). Based on the results, it was revealed that among all the prepared catalysts, that with 3% of zinc had the highest conversion efficiency up to 80%. However, the selectivity of the major products, analyzed by gas chromatography flame-ionization detection (GC-FID), was not influenced by the variation in the active site doping.

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“…These conditions promote the efficient catalytic hydrotreatment of oils. Some studies have found a correlation between higher H 2 flow and reduction in the HDO rates, which could be caused by hydrogen saturation on the catalyst surface. However, other research demonstrates successful catalytic HDO at atmospheric pressure. , These findings suggest that the appropriate catalyst can retard coke formation even under low or atmospheric H 2 pressure.…”

Section: Introductionmentioning

confidence: 99%

Progress and Perspectives in the Catalytic Hydrotreatment of Bio-Oils: Effect of the Nature of the Metal Catalyst

Gil,

Sancho-Sanz,

Korili

2024

Ind. Eng. Chem. Res.

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In recent years, there has been a surge of interest in transforming biomass into fuel, driven by its potential as the only realistic renewable carbon resource. Several conversion methods have been explored to achieve this, including gasification for producing synthesis gas, fast pyrolysis or hydrothermal liquefaction for obtaining bio-oils, and hydrolysis for generating aqueous sugars. Bio-oils offer environmental benefits due to their lower CO 2 emissions, but their direct use as fuels is hindered by limitations such as thermal instability, high viscosity and acidity, and low calorific value. Consequently, advancements in treatment methods are necessary before bio-oils can be used as direct fuels. This review focuses on the catalytic hydrotreatment of bio-oils, which has been shown to be an effective approach for the removal of heteroatoms at moderate temperatures (between 300 and 450 °C) but at high pressures (up to 20 MPa). Oxygenated compounds are transformed into H 2 O, and N and S are transformed into NH 3 and H 2 S, respectively. The analysis examines how process temperature, residence time, hydrogen pressure, solvent selection, and type of catalyst influence the properties of the improved bio-oil. Mo/W sulfide-supported catalysts have been traditionally used as active phases in hydrotreatment processes, as the presence of S limits catalyst deactivation, while the presence of Ni or Co as promoters enhances hydrogenation reactions. New research trends are exploring alternative catalyst formulations, such as metal phosphides, carbides, nitrides, and mesoporous materials as supports with controlled acid-basic properties.

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Gas-phase hydrodeoxygenation of phenol over Zn/SiO2 catalysts: Effects of zinc load, temperature, weight hourly space velocity, and H2 volumetric flow rate

Cited by 15 publications

References 44 publications

Effects of Crystallite Sizes of Pt/HZSM-5 Zeolite Catalysts on the Hydrodeoxygenation of Guaiacol

Effects of Crystallite Sizes of Pt/HZSM-5 Zeolite Catalysts on the Hydrodeoxygenation of Guaiacol

Catalyst Characteristics and Performance of Silica-Supported Zinc for Hydrodeoxygenation of Phenol

Progress and Perspectives in the Catalytic Hydrotreatment of Bio-Oils: Effect of the Nature of the Metal Catalyst

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