Deoxygenation Activity Research Articles

Low-oxygenated biofuels production from palm oil through hydrocracking process using the enhanced Spent RFCC catalysts

Utilization of the enhanced Spent Residue Fluid Catalytic Cracking (SRFCC) catalysts through the acid treatment was conducted for the palm oil hydrocracking process to produce biofuels. The catalysts were characterized using Pyridine-probed Fourier Transform Infrared (Pyridine-FTIR) spectroscopy and Brunauer−Emmett−Teller-Barrett−Joyner−Halenda (BET-BJH) method. The higher number of Brønsted acid sites on the enhanced SRFCC catalysts leads to the lower conversion of palm oil as well as lower deoxygenation activity because of the slower carbocations formation process as the initiation reaction. On the other hand, the Lewis acid sites on the enhanced SRFCC catalysts have a significant role in the deoxygenation reaction mechanism. Meanwhile, the catalysts surface area and pore size are responsible for tailoring the diffusion mechanism of the mass transfer process of reactant molecules. The introduction of hydrogen gas in the reaction system has a significant role in deoxygenation, double bond cleavage, and de-coking process mechanisms.

Biofuels Production from Catalytic Cracking of Palm Oil Using Modified HY Zeolite Catalysts over A Continuous Fixed Bed Catalytic Reactor

The increase in energy demand led to the challenging of alternative fuel development. Biofuels from palm oil through catalytic cracking appear as a promising alternative fuel. In this study, biofuel was produced from palm oil through catalytic cracking using the modified HY zeolite catalysts. The Ni and Co metals were impregnated on the HY catalyst through the wet-impregnation method. The catalysts were characterized using X-ray fluorescence, X-ray diffraction, Brunauer–Emmett–Teller (BET), Pyridine-probed Fourier-transform infrared (FTIR) spectroscopy, and Scanning Electron Microscopy (SEM) methods. The biofuels product obtained was analyzed using a gas chromatography-mass spectrometry (GC-MS) method to determine its composition. The metal impregnation on the HY catalyst could modify the acid site composition (Lewis and Brønsted acid sites), which had significant roles in the palm oil cracking to biofuels. Ni impregnation on HY zeolite led to the high cracking activity, while the Co impregnation led to the high deoxygenation activity. Interestingly, the co-impregnation of Ni and Co on HY catalyst could increase the catalyst activity in cracking and deoxygenation reactions. The yield of biofuels could be increased from 37.32% to 40.00% by using the modified HY catalyst. Furthermore, the selectivity of gasoline could be achieved up to 11.79%. The Ni and Co metals impregnation on HY zeolite has a promising result on both the cracking and deoxygenation process of palm oil to biofuels due to the role of each metal. This finding is valuable for further catalyst development, especially on bifunctional catalyst development for palm oil conversion to biofuels.

New Insights for the Future Design of Composites Composed of Hydrochar and Zeolite for Developing Advanced Biofuels from Cranberry Pomace

This study provides fundamental insight and offers a promising catalytic hydrothermal method to harness cranberry pomace as a potential bioenergy and/or hydrochar source. The physical and chemical properties of Canadian cranberry pomace, supplied by Fruit d’Or Inc., were examined and the optimum operational conditions, in terms of biocrude yield, were obtained by the I-optimal matrix of Design Expert 11. Afterward, cranberry pomace hydrochar (CPH) and zeolite were separately introduced to the hydrothermal liquefaction (HTL) process to investigate the benefits and disadvantages associated with their catalytic activity. CPH was found to be a better host than zeolite to accommodate cellulosic sugars and showed great catalytic performance in producing hydrocarbons. However, high amounts of corrosive amino and aliphatic acids hinder the practical application of CPH as a catalyst. Alternatively, zeolite, as a commercial high surface area catalyst, had a higher activity for deoxygenation of compounds containing carbonyl, carboxyl, and hydroxyl groups than CPH and resulted in higher selectivity of phenols. Due to the low hydrothermal structural stability, coke formation, and narrow pore size distribution, further activations and modifications are needed to improve the catalytic behavior of zeolite. Our results suggest that a composite composed of CPH and zeolite can resolve the abovementioned limitations and help with the development and commercialization of advanced biofuels from cranberry pomace.

The Hydrodeoxygenation of Glycerol over NiMoSx: Catalyst Stability and Activity at Hydropyrolysis Conditions

AbstractCatalytic activity tests were run to elucidate the chemistry and catalyst stability for the hydrodeoxygenation of glycerol and other aliphatic oxygenates over a NiMoSx/Al2O3 catalyst at different pretreatments at hydropyrolysis conditions in a continuous flow reactor. Reactivity metrics were developed to quantify and compare the reactivity of NiMo for deoxygenation, hydrogenation, and C−C cleavage. Activity experiments showed sulfided NiMo and reduced NiMo catalysts had similar deoxygenation and hydrogenation activity for glycerol HDO at 400 °C and 270 psig H2 with the NiMoSx catalyst showing higher C−C cleavage activity. Without a sulfur co‐feed, both the NiMoSx and NiMoOx catalysts lost >40 % deoxygenation activity over 30 h time on stream. With a 2100 ppm H2S co‐feed the NiMoSx catalyst showed a 12 times decrease in the deactivation rate for deoxygenation and 6 time decrease in the deactivation rate for hydrogenation. The main products at high conversion were propylene, propane, ethylene, methane, CO, methanol, ethanol, and 1‐propanol. At low conversion, the major products were unsaturated allyl alcohol, acrolein, hydroxyacetone, and acetaldehyde. With no H2S co‐feed at short contact times, there was a significant amount of carbon loss possibly due to condensation reactions, while at 2100 ppm H2S in the feed, the carbon balance was 102.4 %. Temperature programmed oxidation of the spent NiMoSx catalysts after 30 h of glycerol HDO without an H2S co‐feed showed that one of the causes of deactivation was coking.

Effects of reaction parameter on catalytic hydrothermal liquefaction of microalgae into hydrocarbon rich bio-oil

Hydrothermal liquefaction (HTL) of Spirulina microalgae was studied over different metal supported (Co, Ni and Fe) on carbon nanotube (CNT) in the presence of different solvents (water, ethanol and methanol) for 30 min Reaction time. Maximum bio-oil yield (43.6 wt%). was found with Co/CNT catalyst at 290 °C under ethanol solvent. The catalytic HTL up-gradation decreased the bio-char yield significantly. However the bio-oil quality significantly improved with using the Co/CNT and Ni/CNT catalyst. Also, improved performance with higher amount of bio-oil and lower amounts of bio-char and gas were achieved, which is due the several reactions are happening during the HTL process. Catalytic HTL also revealed that introducing catalysts accelerates the microalgae macromolecules degradation. Being impregnated by metal, catalysts with improved acid sites and thereby, advanced deoxygenation and hydrogenation activities were achieved. Moreover higher percentage of hydrocarbon was obtained with the catalytic liquefaction of microalgae under ethanol solvent. Elemental analysis showed that during the liquefaction reaction promotes the hydrogenation/hydrodeoxygenation and produced less oxygenates bio-oils.

Catalyst structure-based hydroxymethylfurfural (HMF) hydrogenation mechanisms, activity and selectivity over Ni

Catalytic hydrodeoxygenation of hydroxymethylfurfural was investigated in a three-phase batch reactor over a range of reaction temperatures (170–230 °C), under 5 MPa of hydrogen, and tetrahydrofuran solvent. Nickel-based carbon-supported catalysts were also promoted by lanthanum and niobium, despite promoters alone demonstrated no activity. Based on experimentally-obtained liquid products, a reaction pathway was proposed and a microkinetic model was established, by considering adsorption, desorption and surface reaction kinetics, mass transfer and thermodynamics. An unpromoted Ni/C resulted in primarily unsaturated furan diol, a highly desirable intermediate in the polymer industry. As reaction temperatures increased > 200 °C, dehydration yielded deoxygenated products suitable for solvents and biofuel. In spite of enhancements to reducibility, La-promotion significantly decreased both hydrogenation (8-times) and deoxygenation (25-times) rate constants. Alternatively, Nb-incorporation offered additional acidity, while lower activation energies resulted in 200% higher deoxygenation rates via dehydration reactions and humin formation at lower temperatures. It exhibited the highest deoxygenation activity.

Catalytic hydrothermal liquefaction of Gracilaria corticata macroalgae: Effects of process parameter on bio-oil up-gradation

Hydrothermal liquefaction (HTL) of Gracilaria corticata (GC) macroalgae was studied over a series of nickel–iron-layered double oxides (NiFe-LDO) supported on activated bio-char catalysts at 280 °C and different solvents medium. Maximum bio-oil yield (56.2 wt%) was found with 5%Ga/NiFe-LDO/AC catalyst at 280 °C under ethanol solvent. The catalytic HTL up-gradation decreased the bio-char yield significantly. However the bio-oil quality significantly improved with using the 5%Ga/NiFe-LDO/AC catalyst. Also, improved performance with higher amount of bio-oil and lower amounts of bio-char and gas were achieved, which is due the several reactions happening during the HTL process. Catalytic HTL also revealed that introducing NiFe-LDO nanosheets into the activated char could result in NiFe-LDO/AC catalysts of higher surface area and increased active sites. Being impregnated by 5%Ga, catalysts with improved acid sites and thereby, advanced deoxygenation and aromatization activities were achieved. Hence Ga/NiFe-LDO/AC could be considered as a promising catalyst HTL bio-oil upgrading.

RETRACTED: Catalytic co-pyrolysis of rice straw and ulva prolifera macroalgae: Effects of process parameter on bio-oil up-gradation

Co-pyrolysis of rice straw (RS) and ulva prolifera macroalgae (UPM) was studied over a series of nickel-iron-layered double oxides (NiFe-LDO) supported on activated bio-char catalysts. Results showed that, co-pyrolysis produced higher bio-oil yield compared to the individual pyrolysis. Maximum bio-oil yield (46.68 wt%). was found with RS/A-UPM mixture biomass at 500 °C. While RS and UPM and it mixture (RS/UPM) without acid treated UPM was showed lower bio-oil yield. The catalytic pyrolysis up-gradation decreased the bio-oil due to the coke formation. However the bio-oil quality significantly improved with using the 5%Ga/NiFe-LDO/AC catalyst. Also, improved performance with higher amount of bio-oil and lower amounts of char and gas were achieved by acid washing the macroalgae, which is due the removal of ash content or partially fragmented the macromolecule compositions. Catalytic co-pyrolysis of feedstocks also revealed that introducing NiFe-LDO nanosheets into the activated char could result in NiFe-LDO/AC catalysts of higher surface area and increased active sites to adsorb oxygenated and nitrogenated compounds. Being impregnated by 5%Ga, catalysts with improved acid sites and thereby, advanced deoxygenation and aromatization activities were achieved. This implied that the synthesized Ga/NiFe-LDO/AC could be considered as a promising catalyst for RS/A-UPM bio-oil upgrading. • High quality bio-oil by co-pyrolysis of rice straw and ulva prolifera macroalgae. • Acid washing pretreatment considered to enhance the feedstocks synergistic effects. • Highly dispersed NiFe-LDO nanosheets synthesized over obtained activated bio-char. • NiFe, AC, and Ga were used as active phase, support, and promoter. • Advanced catalysts were achieved using Ga impregnation to promote bio-oil quality.

Role of metal support during ru-catalysed hydrodeoxygenation of biocrude oil

Hydrodeoxygenation (HDO) of guaiacol (a lignin-derived species) and biocrude oil was studied in a batch-type reactor operating at 4.0 MPa hydrogen over a series of Ru-based catalysts. Ru/BEA and Ru/ZSM-5, with varying Si/Al ratios, were investigated to examine the effect of pore size and acidity of supports on HDO of guaiacol and biocrude oil. In addition to this, large pore Ru/Al2O3 (possessing weak acid sites, 9.2 nm) and Ru/SiO2 (absence of acid sites, 15.2 nm) were also prepared and examined.It was observed that a decrease in the Si/Al ratio of the support results in an increase in the yield of cyclohexane and a decrease in the yield of 2-methoxycyclohexanol in HDO of guaiacol. This data also discloses the influence of the concentration of acid sites on the deoxygenation of 2-methoxycyclohexanol. Both Ru/BEA and Ru/ZSM-5, with both possessing low Si/Al ratios, display a high activity for HDO for guaiacol, while only the Ru/BEA catalyst exhibits a high activity for HDO of biocrude oil.Catalyst characterisation (BET, NH3-TPD and NH3 and acetonitrile-d3-FTIR) shows that the Ru/BEA catalyst, with a low Si/Al ratio, not only possesses strong Brønsted acid sites but also contains extensive mesoporosity. Notably, these mesopores appear to facilitate the hydrogenation, deoxygenation, and ring-opening of large oxygenated and condensed-ring hydrocarbons in biocrude oil which then leads to a high yield of cycloalkanes. As expected, the Ru/Al2O3 and Ru/SiO2 catalysts exhibit a high hydrogenation activity but a lower deoxygenation activity in the HDO of guaiacol and biocrude oil.These results suggest that the larger pore support, with strong Brønsted acid sites, engendered the HDO activity observed. The reaction pathway for the main components of biocrude oil was proposed based on the observed reaction product distribution.

Performance-screening of metal-impregnated industrial HZSM-5/γ-Al2O3 extrudates for deoxygenation and hydrodeoxygenation of fast pyrolysis vapors

Screening of catalysts for deoxygenation and atmospheric hydrodeoxygenation of fast pyrolysis vapors from biomass (wheat straw) was performed using a micro-scale setup. Steam-treated HZSM-5/Al2O3 extrudates were impregnated with metals by incipient wetness impregnation. 18 different metal modifiers (Pt, Pd, Ru, B, Li, Nb, Ga, Ca, Mg, Ce, Zn, Fe, Ni, Cu, Mo, Co, La, Zr) were tested, of which 14 were tested under inert atmosphere and 10 were tested in H2 containing atmosphere. The catalysts were evaluated based on the yield of individual product groups (incl. gas and coke), the oxygen content of the vapors, and the yield of vapor compounds containing, zero, one, and two-or-more oxygen atoms. The deactivation was monitored during 16 consecutive vapor pulses and cumulative product properties at B:C ∼4 were compared.In He atmosphere, a slight improvement of the deactivation behavior and the resulting cumulative vapor properties was observed for impregnation with Mg, B, Fe and Zr, but generally, the benefits were moderate or absent. Ga, Co, Ni, Fe, Cu, Mo, Nb, Pt, Ru, and Pd-modified HZSM-5/Al2O3 were tested in H2-containing atmosphere. A clear enhancement in catalytic activity resulted for Co, Fe, and Pd, achieving 21–26 % lower oxygen content compared to the unmodified HZSM-5/Al2O3. Even higher deoxygenation activity resulted for Ni, Mo, and Pt impregnated HZSM-5/Al2O3, achieving 35 %, 40 %, and 46 % lower oxygen content compared to HZSM-5/Al2O3. The results are attributed to a more favorable reaction chemistry such as hydrodeoxygenation and hydrogenation of coke precursors. Coke yields were clearly decreased compared to the parent HZSM-5/Al2O3 for the majority of the metal modifiers under H2 atmosphere, while under He atmosphere coke yields tended to be higher. Based on the high yields of gasoline-range hydrocarbons and considering catalyst costs, Mo-promoted HZSM-5/Al2O3 appears to be a promising catalyst that should be tested in hydrogen-containing atmosphere at larger scale allowing for further assessment of the liquid yield and properties.

Green diesel production by solvent-free deoxygenation of oleic acid over nickel phosphide bifunctional catalysts: Effect of the support

An alternative to non-renewable fuels is the production of green diesel from deoxygenation of vegetable oils. In this study, the effect of the supports on nickel phosphide catalysts for deoxygenation of oleic acid to produce hydrocarbons was investigated. Nickel phosphide catalysts supported on USY, H-ZSM-5 and Al-SBA-15 were synthetized by temperature programmed reduction (TPR) of metal phosphate precursors and the prepared catalysts were characterized by atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), small angle X-ray scattering (SAXS), temperature programmed reduction of hydrogen (TPR), nitrogen physisorption, temperature programmed desorption of ammonia (TPD), transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR). The catalytic tests were performed in an autoclave batch reactor at 260 °C, 280 °C and 300 °C and 50 bar of hydrogen. The production of hydrocarbons (C10-C18) at 300 °C followed the order: Ni2P/Al-SBA-15 > Ni2P/H-ZSM-5 > Ni2P/USY. The Ni2P/Al-SBA-15 exhibited a remarkable deoxygenation activity, compared to noble metals. All the catalysts achieved more C17 than C18 hydrocarbons, therefore, decarbonylation/decarboxylation reactions prevail. With regard the temperature effect, the amount of hydrocarbons increased from 260 °C to 280 °C but it decreased from 280 °C to 300 °C for all catalysts, which can be ascribed to catalyst deactivation.

Effective catalytic deoxygenation of palm fatty acid distillate for green diesel production under hydrogen-free atmosphere over bimetallic catalyst CoMo supported on activated carbon

Palm fatty acid distillate (PFAD) is considered as an inedible and renewable feedstock for the production of green diesel. In the current study, green diesel was successfully synthesised via catalytic deoxygenation of PFAD in an environment free of H2 using a mesoporous activated carbon (AC) supported CoMo catalyst with various molybdenum (Mo) concentrations (5–20 wt%). Based on the study results, bimetallic catalyst Co10Mo10/AC formulation exhibited excellent catalytic performance with 92% hydrocarbon components (C8-C20) yield and 89% selectivity for n-(C15 + C17) with a total acid number of 24 mg KOH mg−1. Based on a comparison study with various supports (AC, γ-Al2O3, TiO2), the AC-supported CoMo catalyst showed higher deoxygenation activity than both Co10Mo10/γ-Al2O3 and Co10Mo10/TiO2 owing to the super acid-base sites as a result of synergism between the CoMo and AC support. The Co10Mo10/AC catalyst demonstrated excellent stability during the study as it maintained the hydrocarbon components yield and selectivity of n-(C15 + C17) >80% until the sixth run.

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 Intermediate Pyrolysis of Cellulose for Hydrocarbons Production in the Presence of Zeolites by Using TGA-FTIR Method

Pyrolysis plays a vital role in biomass conversion as one of the most promising thermal conversion routes. Solid, liquid and gaseous products are obtained from biomass pyrolysis. The liquid is considered as perspective fuel; however, the direct use of bio-oil as fuel may present many difficulties due to its high viscosity, poor heating value and relative instability. This creates a significant economic barrier for production of transportation fuel by pyrolysis process. Catalytic pyrolysis has been widely used as a convenient method for the direct conversion of biomass into higher quality liquid bio-fuels. Intermediate pyrolysis of cellulose (as a model substance for biomass) with or without catalysts was investigated using TGA-FTIR method in order to determine the influence of zeolite on the relative yield of the compounds. The addition of zeolite with medium and weak acidity increased the production of volatile matter from 86.1% to 88.5% and 88.9% under the catalyst of MCM-41 and ZSM-5 (70). Zeolite with high acidity contributes to the formation of coke and simultaneously causing the deactivation of the catalyst, thus decreasing the volatile matter of cellulose from 86.1% to 83.6% and 83.2% by using H-ZSM-5 (23) and H-ZSM-5 (50). All catalysts showed deoxygenation activity. Zeolites had higher activity in the deoxygenation of compounds containing hydroxyl group than compounds containing carbonyl and carboxyl groups. H-ZSM-5 (23) had a substantial effect on the production of monoaromatic hydrocarbons whereas the yield of olefins notably increased in the presence of ZSM-5 (70).

Effect of Composition of Iron-Cobalt Oxide Catalyst and Process Parameters on The Hydrothermal Liquefaction of Sugarcane Bagasse

Development of catalyst with high deoxygenation activity and optimum process parameters are the key for getting the highest biooil yield with the least oxygen content by hydrothermal liquefaction. With this view, iron-cobalt oxides of Co/Fe ratio 0.33, 1.09, 2.35, and 3.52 were prepared by co-precipitation method, and characterized by XRD, BET surface area, chemical composition by EDX method, and evaluated for hydrothermal liquefaction of sugarcane bagasse in a high-pressure batch reactor under subcritical conditions using CO as process gas to find the optimum Co/Fe ratio and process parameters. Optimum Co/Fe ratio was found to be 1.09 as it gave the highest bio-oil yield of 57.6% with the least oxygen content of 10.8%, attributed to the cobalt ferrite, the major phase present in it. The optimum temperature, initial CO pressure, water/biomass ratio, catalyst/biomass ratio and reaction time for the highest oil yield with the least oxygen content were found to be 250 °C, 45 bar, 28, 0.4, and 120 min, respectively. From the effect of reaction time, it was found that much of the hydrolysis of lignocellulose to water soluble oxygenates, its deoxygenation to bio-oil and its deoxygenation to low oxygen containing bio-oil took place in initial 15 min, 15 to 60 min, and from 30 to 120 min, respectively. Total oil yield (%) was lower by 21% and % oxygen in total oil was higher by 9.9% for spent catalyst compared to fresh catalyst indicating the erosion in the deoxygenation activity of catalyst and thus need for improving its hydrothermal stability. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Prevention of CaO deactivation using organic calcium precursor during multicyclic catalytic upgrading of bio-oil

The conversion of biomass wastes into upgraded bio-oil has been successfully implemented by catalytic fast pyrolysis (CFP) with CaO catalyst. The bottleneck of CFP technology is catalyst deactivation. Ex-situ catalytic pyrolysis of biomass wastes with multiple recycling of CaO from different calcium precursors were performed in a continuous fixed-bed at 500 °C. The objectives were to intensify the anti-deactivation and regenerative stability of CaO using organometallic precursor, and comprehensively distinguish the effects of calcium precursors on deactivation mechanism in terms of coke yield, coke species, structural and chemical changes et al. The results demonstrated that organic calcium precursor strengthened the recyclability of CaO catalyst during upgrading of bio-oil by showing longer lifetime and better recycling stability. Compared with conventional CaO from Ca(OH)2 (CH-CaO), the stronger deoxygenation and superior porosity of CaO from organic calcium precursors (Org-CaO) facilitated the removal of coke precursors and suppressed pore plugging. The average coke yields of CH-CaO and Org-CaO were respectively 5.1 and 2.2 g/m2. Moreover, CH-CaO promoted the aromatization of coke precursors, leading to coke existing in form of hard diamond-like structure. But coke deposited on Org-CaO exhibited softer layered graphite structure and contained more aliphatic matters. After 10 reaction/regeneration cycles, Org-CaO still kept 50% deoxygenation activity whereas CH-CaO showed almost complete deactivation. Organic calcium precursors delayed irreversible deactivation of CaO, since these precursors physically prevented the sintering and agglomeration of CaO, and chemically alleviated the loss of both the strength and density of basic sites on CaO.

Solvent-Free Hydrodeoxygenation of Triglycerides to Diesel-like Hydrocarbons over Pt-Decorated MoO2 Catalysts.

In the present work, the solvent-free hydrodeoxygenation of palm oil as a representative triglyceride model compound to diesel-like hydrocarbons was evaluated in a batch reactor using Pt-decorated MoO2 catalysts. The catalysts with various Pt loadings (0.5–3%) were synthesized by an incipient wetness impregnation method. The metallic Pt and MoO2 phases were detected in the XRD patterns of as-prepared catalysts after the reaction and acted as active components for the deoxygenation reactions. The XPS experiments confirmed the existence of metallic Pt and PtOx species. The XANES investigation of Mo L3-edge spectra elucidated a change in the valence state by the transformation of MoO3 into MoO2 species after the deoxygenation reaction. The TEM observation revealed the formation of Pt nanoparticles in the range of 1–3 nm decorated on MoO2 species. The number of acid sites increased with stronger metal–support interactions on increasing the Pt loading. The catalytic performance of the MoO2 catalyst significantly improved with a small amount of Pt decoration. However, the further increase in Pt loading did not relatively increase the deoxygenation activity due to the formation of the agglomerated Pt particles. The high performance of the decorated catalysts could be attributed to the moderate acidity from the Pt dispersed on MoO2 toward decarbonylation and decarboxylation reactions.

Stability of Li-LSX Zeolite in the Catalytic Pyrolysis of Non-Treated and Acid Pre-Treated Isochrysis sp. Microalgae

This paper investigates the use of Li-LSX-zeolite catalyst over three regeneration cycles in presence of non-treated and acid pre-treated Isochrysis sp. microalgae. The spent and regenerated catalysts were characterised by surface analysis, elemental analysis (EA), SEM-EDS, and XRD to correlate their properties with the bio-oil yield and quality. The acid pre-treatment removed alkali metals, reducing gas yield in favour of bio-oil, but, at the same time, led to catalyst deactivation by fouling. Differently, the non-treated microalgae resulted in a bio-oil enriched in C and H and depleted in O, compared to the pre-treated ones, denoting higher deoxygenation activity. After 3 pyrolysis/regeneration cycles, the analyses suggest that there are no major changes on catalyst using non-treated microalgae. Regeneration at 700 °C has been shown to be able to remove most of the coke without damaging the Li-LSX zeolite structure. In summary, Li-LSX zeolite was effective in maintaining deoxygenation activity over three cycles in the pyrolysis of non-treated Isochrysis microalgae, while the algae pre-treatment with sulphuric acid was detrimental on the catalyst activity.

Deoxygenation of triolein to green diesel in the H2-free condition: Effect of transition metal oxide supported on zeolite Y

H2-free deoxygenation is a very important process in producing high-quality biofuel without the use of H2 gas supply. Considering the costly price of the noble metals, transition metal (TM) based catalysts are more affordable, and the performance is comparable to the noble metal-based catalyst. In this study, TMO supported on zeolite Y catalysts (Ni-, Cu-, Co-, Zn- and Mn-Y) are prepared via wet-impregnation for deoxygenation of triolein, a model compound of non-edible oil under H2-free condition. The deoxygenation activity of TMO supported on zeolite Y is following the order of Ni-Y > Co-Y > Cu-Y > Mn-Y > Zn-Y. The nickel oxide supported on zeolite-Y (Ni-Y) shows the highest conversion up to 76.21 % with 84.28 % hydrocarbon selectivity after reacted at 380 °C for 2 h. Besides, the selectivity toward diesel range hydrocarbon is 92.61 %. The superior deoxygenation activity of Ni-Y can be related to synergistic effect between the reduced B/L and high hydrogenolysis ability of Ni that promote the decarboxylation reaction, suppress the cracking and polymerization of heavy hydrocarbon. Therefore, Ni-Y is a potential catalyst to obtain high quality green diesel from non-edible oil through catalytic deoxygenation without addition of external H2 source.

Catalytic Thermochemical Conversion of Algae and Upgrading of Algal Oil for the Production of High-Grade Liquid Fuel: A Review

The depletion of fossil fuel has drawn growing attention towards the utilization of renewable biomass for sustainable energy production. Technologies for the production of algae derived biofuel has attracted wide attention in recent years. Direct thermochemical conversion of algae obtained biocrude oil with poor fuel quality due to the complex composition of algae. Thus, catalysts are required in such process to remove the heteroatoms such as oxygen, nitrogen, and sulfur. This article reviews the recent advances in catalytic systems for the direct catalytic conversion of algae, as well as catalytic upgrading of algae-derived oil or biocrude into liquid fuels with high quality. Heterogeneous catalysts with high activity in deoxygenation and denitrogenation are preferable for the conversion of algae oil to high-grade liquid fuel. The paper summarized the influence of reaction parameters and reaction routes for the catalytic conversion process of algae from critical literature. The development of new catalysts, conversion conditions, and efficiency indicators (yields and selectivity) from different literature are presented and compared. The future prospect and challenges in general utilization of algae are also proposed.