The solid fraction obtained by mechanical separation of digestate from anaerobic digestion plants is an attractive feedstock for the pyrolysis process. Especially in the case of digestate obtained ...from biogas plants fed with energy crops, this can be considered a lignin rich residue. The aim of this study is to investigate the pyrolytic kinetic characteristics of solid digestate. The Starink model-free method has been used for the kinetic analysis of the pyrolysis process. The average Activation Energy value is about 204.1 kJ/mol, with a standard deviation of 25 kJ/mol, which corresponds to the 12% of the average value. The activation energy decreased along with the conversion degree. The variation range of the activation energy is about 99 kJ/mol, this means that the average value cannot be used to statistically represent the whole reaction. The Master-plots method was used for the determination of the kinetic model, obtaining that n-order was the most probable one. On the other hand, the process cannot be modeled with a single-step reaction. For this reason it has been used an independent parallel reactions scheme to model the complete process.
Selective oxidation of alcohol to the corresponding aldehyde plays a pivotal role in organic synthesis. In the present study, 3D cubic cage-like mesoporous SBA-16 was synthesized by a one-pot ...hydrothermal route. Then SBA-16 supported MnMoO
4
catalysts, designated as MnMoO
4
(1, 3, and 5wt.%)/SBA-16, were prepared by the wet impregnation method. The catalysts were thoroughly characterized by various analytical techniques to verify phase purity, mesoporous structure, morphology, and oxidation state of the catalytic active sites. Further, catalytic activity was performed for the liquid phase oxidation of salicyl alcohol and its family members to obtain the respective aldehydes between 50 and 90 °C. MnMoO
4
(3 wt.%)/SBA-16 showed higher catalytic activity than other catalysts by giving 88% salicyl alcohol conversion with 81% salicylaldehyde selectivity. The recovered catalyst retained activity for five cycles, thus proving MnMoO
4
(3 wt.%)/SBA-16 is a better choice for commercial production of salicylaldehyde.
Graphical abstract
In the present work, birch and spruce woodchips were pyrolyzed in a fixed bed reactor under different pyrolysis conditions. The effects of pyrolysis temperature and atmosphere (i.e., with and without ...gas purging) on yield and chemical composition of liquid products were investigated. The liquid products from the pyrolysis experiments were condensed, collected and analysed by using a gas chromatograph equipped with a mass spectrometer (GC/MS). The results showed that the yields of liquid products from pyrolysis of birch and spruce wood were different upon changes of pyrolysis temperature, purge gas flow rate and the different initial fuel chemical compositions. Higher yield of liquid products was obtained from pyrolysis of the birch wood at higher temperature or with purging of N2. The organic composition of liquid products from pyrolysis of spruce and birch wood is dominated by acetic acid, levoglucosan, and oxygenated aromatic compounds consisting mainly of phenol and phenol derivatives. Change of pyrolysis conditions caused changes in the chemical composition of liquid products from pyrolysis of birch wood. The chemical composition of liquid products from pyrolysis of birch and spruce wood are different, which is mainly related to different chemical composition of these two kinds of wood, being respectively hardwood and softwood.
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Catalytic pyrolysis of digestate to produce aromatic hydrocarbons can be combined with anaerobic fermentation to effectively transform and utilize all biomass components, which can ...achieve the meaningful purpose of transforming waste into high-value products. This study explored whether catalytic pyrolysis of digestate is feasible to prepare aromatic hydrocarbons by analyzing the thermogravimetric characteristics, pyrolysis characteristics, and catalytic pyrolysis characteristics of digestate. For digestate pyrolysis, an increase in temperature was found to elevate the CO, CH4, and monocyclic aromatic hydrocarbon (benzene, toluene, and xylene; BTX) content, whereas it decreased the contents of phenols, acids, aldehydes, and other oxygenates. Furthermore, the catalytic pyrolysis process effectively inhibited the acids, phenols, and furans in the liquid, whereas the yield of BTX increased from 25.45% to 45.99%, and the selectivity of xylene was also increased from 10.32% to 28.72% after adding ZSM-5. ZSM-5 also inhibited the production of nitrogenous compounds.
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•The KIT-6/HZSM-5 was synthesized by the hydrothermal method in an acidic medium.•The different wt.% of RuO2-NiO over KIT-6/HZSM-5 was impregnated.•All the synthesized catalysts were ...characterized by XRD, FT-IR, N2 sorption, TPR, TPD, TGA, HR-SEM, HR-TEM, and XPS techniques.•The synthesized catalysts were investigated for HDO of Eugenol in a fixed bed reactor under optimized reaction conditions.•The optimized catalyst showed 100% conversion and high selectivity toward Hydrocarbon due to the synergetic effects of Ru-Ni, and the KIT-6/HZSM-5.
A novel hierarchical Zeolite composite was successfully synthesized for bio-fuel application via catalytic hydrodeoxygenation of Lignin-Derived Phenolic Model Compound (LDPMC) in a downflow fixed bed reactor. The utilization of massive noble metals in the hydrodeoxygenation process in factories leads to an increase in the total cost of LDPMC technology. A fractional replacement of Ruthenium (Ru) by another transition metal Nickel (Ni), is a potentially effective method. The core asset of the novel synthesized catalyst displayed the advantageous properties of both micro- and mesoporous. This could be confirmed by the results of XRD, BET, and surface analyzing microscopes. The synthesis of Rux-Ni10-x/KIT-6-HZSM-5 (x = 2, 4 & 6) bimetallic-monometallic catalysts and their catalytic performance for hydrodeoxygenation of Eugenol are reported in the present study. The hierarchical Zeolite composite catalysts were synthesized by a wet-chemistry method. The active catalysts were characterized by ATR-IR, H2-TPR, NH3-TPD, HR-SEM, HR-TEM, XPS, and TGA techniques. The synthesized 2 %Ru-8 %Ni/KIT-6-HZSM-5 exhibited 100 % conversion with a maximum yield of 48.70 % of the complete deoxygenated product (Jet A range fuel) due to the synergistic effect between Ru and Ni on hierarchical Zeolite composite support and superior catalytic activity compared to the other synthesized catalysts with the highest metal dispersion. The stability and reproducibility of catalysts were steady even after 4 cycles. The Ruthenium and Nickel loaded hierarchical Zeolite composite support showed superior activity related to other reported catalysts even at atmospheric pressure under variable experimental conditions.
A cluster of eleven research and innovation projects, funded under the same call of the EU's H2020 programme, are developing breakthrough and game-changing renewable energy technologies that will ...form the backbone of the energy system by 2030 and 2050 are, at present, at an early stage of development. These projects have joined forces at a collaborative workshop, entitled '
', at the 10th Sustainable Places Conference (SP2022), to share their insights, present their projects' progress and achievements to date, and expose their approach for exploitation and market uptake of their solutions.
A cluster of eleven research and innovation projects, funded under the same call of the EU’s H2020 programme, are developing breakthrough and game-changing renewable energy technologies that will ...form the backbone of the energy system by 2030 and 2050 are, at present, at an early stage of development. These projects have joined forces at a collaborative workshop, entitled ‘
Low-TRL Renewable Energy Technologies
’, at the 10th Sustainable Places Conference (SP2022), to share their insights, present their projects’ progress and achievements to date, and expose their approach for exploitation and market uptake of their solutions.
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•Two-step reactions process via catalytic methane decomposition and Reverse Boudouard Reaction.•First convert methane to CO22-free hydrogen and a second step to convert the solid ...carbon via CO2 gasification to CO.•Effect of catalyst preparation method via solution combustion synthesis and impregnation on 5wt% Ni supported on SiO2.•Key factors are Ni nanoparticle size and distribution, strength of metal support interaction, & nature of graphitic carbon.
Catalytic methane decomposition is a promising reaction to produce CO2-free hydrogen from methane-rich feedstock with solid carbon as a by-product. Significant research conducted on this reaction to find ways to manage and utilize this solid carbon. In this work, the methane decomposition reaction is followed by Reverse Boudouard Reaction using CO2 feedstock to convert the solid carbon to carbon monoxide, which is a valuable starting component for many chemical applications. Realizing this promising concept would require a catalyst that is efficient for both reactions. Herein, we explored the potential of using solution combustion synthesis (SCS) to make a 5 wt% of Ni supported SiO2 catalyst and benchmarked it versus the conventional impregnation method. The catalyst prepared by SCS showed an improved performance at different temperatures, space velocities, and catalyst pellet sizes. The SCS catalyst successfully completed five repeated cycles reaching up to 38.1 h of stable time on stream operation, whereas the impregnated catalyst was not able to complete the second testing cycle with only 14 h of time on stream operation. A thorough characterization using XRD, H2 and O2 TPR, TEM, SEM, XPS, and Raman spectroscopy were conducted to provide an adequate explanation for the observed performances for both catalysts. The Ni nanoparticles size and distribution, the strength of the metal support interaction, and the nature of graphitic carbon were the key factors affecting the catalytic performance. Insights on how to make an optimal catalyst for this promising process is identified which is a step forward toward making separated H2 and CO streams from methane feedstock and CO2, respectively.
In this work, different metal oxides (MO) supported on two types of zeolites:
1) natural clinoptilolite (NZ) and 2) synthetic zeolite, ZSM-5 were prepared
and tested as catalysts in the fast ...pyrolysis of hardwood lignin. NZ was
modified with the CaO and MgO by a simple two steps procedure consisting of
an ion exchange reaction and a subsequent calcination at 773 K. The synthetic
ZSM-5 was modified with several MO species (Ni, Cu, Ca, Mg) by a wet
impregnation and calcination at 873 K. ?he prepared catalysts were
characterized by X-ray diffraction analysis (XRD), scanning electron
microscopy and energy dispersive X-ray analysis (SEM/EDS) and measurement of
specific surface area (BET method). Acid sites were characterized and
quantified by pyridine (py) absorption using Fourier transform infrared
spectroscopy (FTIR). The catalysts exhibit catalytic activity depanding on
modification, reaction temperature and of the MO contents. The highest yield
of useful phenol in bio-oil was obtained with NiO/ZSM-5 (34.8 wt.%) which
exhibits the highest specific surface area and the highest concetration of
Br?nsted and Lewis acid sites. The studied catalysts did not increase
significantly the content of polycyclic aromatic hydrocarbons (PAHs) and
heavy compounds compared to non-catalytic experiment.
Abstract
Biodiesel, an important sustainable fuel used in the transportation sector, demands a stable, recyclable and green catalyst for its economical and environmentally benign production. A novel ...green heterogeneous acid catalyst was developed by extracting sodium silicate from bamboo leaf ash (BLA), using which SBA-16 (BLA) was synthesized and then impregnated with 10 wt% each of WO
3
and ZrO
2
, characterized and evaluated for the transesterification of Ankol seed oil with methanol to biodiesel. XRD, SEM, TEM and pore size characterization indicated that impregnated WO
3
and ZrO
2
were present outside the mesopores of SBA-16 (BLA) as monoclinic phases, thus 3D cubic cage-like Im3m mesopores of SBA-16 were unaltered. NH
3
-TPD indicated the presence of acid sites of two distinct strengths, attributed to the Lewis and Brønsted acidity of WO
3
–ZrO
2
impregnated into SBA-16 (BLA) and hence gave the highest biodiesel yield of 98 %. In contrast 10 wt% of WO
3
and 10 wt% of ZrO
2
separately impregnated into SBA-16 gave 65 and 57 % of biodiesel yield respectively, possibly due to the presence of Lewis acidity alone in them. Among the WO
3
(10 %)–ZrO
2
(10 %) impregnated mesoporous supports viz. SBA-16 (BLA), SBA-16 (synthesized using tetraethyl orthosilicate), SBA-15, MCM-41, MCM-48, KIT-6, FDU-5, and TUD-1, the highest biodiesel yield of 98 % was given by SBA-16 (BLA), attributed to its spherical morphology and strong interaction with WO
3
–ZrO
2
as inferred from SEM and XPS characterizations respectively. From the effect of process parameters on the WO
3
(10 %)–ZrO
2
(10 %)/SBA-16 (BLA) catalyst, maximum biodiesel yield was obtained at the temperature of 65 °C, catalyst amount of 200 mg, methanol:oil weight ratio of 10:1 and reaction time of 3 h. Under these reaction conditions, it retained the same biodiesel yield for six recycles after regeneration every time, confirmed its catalytic stability and recyclability.
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