Bio-oil Yield Research Articles

Characterisation analysis of bio oil generation using Hibiscus cannabinus seeds

Bio-oil from Hibiscus cannabinus seeds was extracted with four solvents: acetone, benzene, isopropanol, and hexane. Solvent extraction techniques have less oil residue than other methods. The primary factors that influence the extraction processes such as extraction time, particle size, seed ageing, and solvent suitability were optimised to enhance the bio-oil yield. The extracted bio-oil was tested by GC-MS, FTIR, and 1H-NMR. Physicochemical properties (free fatty acid, specific gravity, acid value, calorific value, saponification number, iodine number, etc.) of hibiscus cannabinus oil were also analysed on a dry weight basis. The hexane solvent gave the highest yield (25.37%) followed by acetone (21.32%), Benzene (16.98%), and Isopropanol (14.20%) over 3.5 h. It is also predicted that the cost of Hibiscus cannabinus seed bio-oil per litre is Rs. 230 which is moderately economical Hibiscus cannabinus oil has a calorific value of 39,895 kJ/kg, making it a better fuel choice.

The Influence of Pyrolysis Time and Temperature on the Composition and Properties of Bio-Oil Prepared from Tanjong Leaves (Mimusops elengi)

This research aims to evaluate the influence of pyrolysis time and temperature on the composition and properties of bio-oil derived from Mimusops elengi. Experiments were conducted by varying the pyrolysis temperature and time from 400 to 600 °C and 30 to 120 min, respectively. Both pyrolysis temperature and time were found to significantly influence the bio-oil composition. At enhanced pyrolysis temperatures, the bio-oil yield increased while the ash and gas yields decreased. In addition, extended pyrolysis time produced a greater bio-oil yield, indicating that higher temperatures and longer durations promote additional decomposition of biomass. Functional groupings, including alcohols, phenols, ketones, esters, and aromatic compounds in the bio-oil, were identified via FT-IR analysis, indicating that the bio-oil’s diversified chemical properties make it a potential alternative feedstock. GC-MS analysis identified 26 chemical compounds in the bio-oil, of which phenol was the most abundant. However, a high phenol content can diminish bio-oil quality by enhancing acidity, decreasing heating value, and encouraging engine corrosion. Temperature and pyrolysis time are crucial factors in producing bio-oil with the desired chemical composition and physical properties. The maximum yield, 34.13%, was attained after 90 min of operation at 500 °C. The characteristics of the Mimusops elengi bio-oil produced, namely density, viscosity, pH, and HHV were 1.15 g/cm3, 1.60 cSt, 4.41, and 19.91 MJ/kg, respectively, in accordance with ASTM D7544. Using Mimusops elengi as a pyrolysis feedstock demonstrates its potential as an environmentally friendly energy source for a variety of industrial and environmental applications. The yield of bio-oil produced is not optimal due to the formation of tar, which results in the blockage of the output flow during the pyrolysis process.

Hydrothermal liquefaction of Moroccan two-phase olive mill waste (alperujo): Parametric study and products characterizations

The primary objective of this study is to investigate the hydrothermal liquefaction of two-phase olive mill waste (TPOMW). Consequently, a parametric study of the two-phase olive mill waste hydrothermal liquefaction was conducted using a batch reactor to screen different experimental operating conditions. Experiments were conducted at different temperatures: 260, 280, and 300 °C, dry-matter/water ratios: 0.05, 0.10, and 0.15, and residence times: 0 (no isotherm step), 30, 45, and 60 min. The product (gases, bio-oils, hydrochar) yields, global carbon mass balances, elemental composition (CHNS-O), and energy yield obtained were evaluated for each experimental condition. The operating condition at 280 °C with 0.15 dry-matter/water ratio and no isotherm step resulted in the maximum energy yield of the process (87%). Under these conditions, the bio-oil and hydrochar yields were equal to 37.2 wt% and 22.6 wt% of initial dry matter, respectively. Analysis of the products showed that the produced bio-oil (30.8–32.1 MJ/kg) and hydrochar (27.7–30.6 MJ/kg) presented higher values than lignite and coal, thus, these products can potentially be used for energetic insights. In terms of BO composition, FT-IR analysis exhibited the presence of some compounds such as carboxylic acids phenols, and esters. GC-FID/MS analysis showed that the produced bio-oils are rich in phenolic compounds, oleic acid, hexadecanoic acid, fatty acid methyl ester, and fatty acid ethyl ester, which is in accordance with FT-IR analysis.

Study on Process Parameters in Hydrothermal Liquefaction of Rice Straw and Cow Dung: Product Distribution and Application of Biochar in Wastewater Treatment

In this study, rice straw (RS) and cow dung (CD) waste were hydrothermally processed for the recovery of bio-oil and biochar. The hydrothermal experiments were performed in a 5 L capacity reactor under the following process conditions: temperature (240–340 °C), solvent to biomass ratios of 1:1, 1:2, 2:1, 1:3 and 3:1, a time of 1 h and a pressure of 15 bar. The HTL products were characterized via FTIR, SEM and GC–MS (gas chromatography mass spectrometry). It was seen that the maximum bio-oil yield was 32.5 wt% and the biochar yield was 18.5 wt% for the 2:1 RS:CD mixture at a temperature of 320 °C. The bio-oil contained hexadecane, heptadecane, octadecane and other hydrocarbons, and their presence was confirmed by GC–MS. The biochar was analyzed, and it was used in wastewater treatment to remove the colorants. The biochar also showed some promising results in the colorants removal study, with an efficiency of more than 76%.

The effect of citric acid pretreatment on composition and stability of bio-oil from sugar cane residues using a continuous lab-scale pyrolysis reactor

This study outlines the effect of citric acid leaching on the quality and stability of fast pyrolysis bio-oils from sugarcane bagasse (SCB) and sugarcane trash (SCT). The quality of bio-oil was probed by GC-MS analysis, elemental composition, higher heating value, water and solids content, pH, dynamic viscosity and stability (ageing). Pyrolysis was performed at 500 °C in a fully controlled, continuously operated plant with a biomass throughput of ca. 300 g.hr−1. While citric acid leaching causes a decrease of the average bio-oil yield with 5%, it does not lead to a bio-oil with improved fuel-related properties. However, the bio-oil composition became more advantageous in light of its biorefining. Indeed, citric acid leaching led to an increased levoglucosan concentration – a promising platform chemical – of 17% for SCB and of to 35% for SCT (based on relative abundance in GC-MS). In tandem, the concentration of carboxylic acids and phenols in the bio-oil decreased after citric acid leaching, which is beneficial for downstream purification of levoglucosan. Regarding the non-condensable gases, CO and CO2 represented between 88% and 91% by weight of the total non-condensable gases produced in pyrolysis. Therefore, the results of this study demonstrate that optimized biomass demineralization pretreatment with citric acid could produce bio-oil at high yield and rich in high-value chemical compounds like levoglucosan. Biomass demineralization pretreatment however, does not result in bio-oil with improved quality for fuel purposes, nor does it necessarily lead to bio-oil having higher stability.

Microwave catalytic co-pyrolysis of chlorella vulgaris and oily sludge by nickel-X (X = Cu, Fe) supported on activated carbon: Characteristic and bio-oil analysis

Microwave co-pyrolysis of chlorella vulgaris (CV) and oily sludge (OS) was conducive to improving pyrolysis characteristics and bio-oil quality. In this study, activated carbon (AC) was used as carrier to prepare metal supported catalysts (Ni/AC, Ni–Cu/AC and Ni–Fe/AC), and the effects of catalysts with different additions (5%, 10% and 15%) on co-pyrolysis of CV and OS were investigated by microwave pyrolysis furnace. The results indicated that metal supported catalysts improved the co-pyrolysis characteristics, especially at 10% addition amount. The maximum average rate of weight loss (Rv) and minimum reaction time (Ts) occurred in the 10% Ni–Fe/AC group. Moreover, addition of 10% metal supported catalysts showed promoting effect on producing bio-oil, and the maximum bio-oil yield (22.1%) obtained in the 10% Ni–Cu/AC group. GC-MS analysis indicated that addition of 10% Ni–Fe/AC increased aliphatic hydrocarbons in bio-oil to 44.52%, while 10% Ni/AC increased hydrocarbons to 76.62%. Furthermore, the deoxidization efficiency of bio-oil exceeded 35% with metal supported catalysts adding. The maximum deoxidization efficiency (46.57%) was obtained when adding 10% Ni–Fe/AC.

Numerical optimization of hydrothermal liquefaction process for the production of bio-oil and bio-char from Citrus maxima peel waste and product characterization.

This research study aims to potential utilization of Citrus maxima peel waste and optimize the hydrothermal liquefaction process for the production of bio-oil (BO) and bio-char (BC). The effect of several HTL processing variables on BO yield (%) and BC yield (%), including temperature, retention period, and slurry concentration, has been examined using central composite design (CCD) (a three-level three-factor design). The optimized values of HTL process variables were found to be 240°C (temperature), 52min (retention time), and 7% (slurry concentration) and the corresponding responses were 5.794% (BO yield) and 29.450% (BC yield). The values obtained from the RSM-CCD model as the predicted values agreed with the experimental values (5.93% and 30.14%). Further the BO and BC obtained under optimized conditions and CPP were analyzed to identify the variations by 1H-NMR, GC-MS, FT-IR, and CHNO-S.

Catalytic hydrothermal liquefaction of water hyacinth: An investigation into bio-oil generation and co-synthesis of Cu core-shell carbon hybrids

ABSTRACT The present study involved examining the hydrothermal liquefaction of Cu-impregnated water hyacinth for bio-oil production, and the co-synthesis of Cu Core-shell carbon hybrids. Effects of operating parameters such as temperature and Cu-impregnated biomass-to-water ratio on bio-oil and carbon hybrid yield were discussed. Results showed the highest total bio-oil yield of 34.82% was attained at 280°C with a biomass-to-water ratio of 1:9 at a residence time of 15 min. Carbon nanometal hybrids were characterized by TEM and FESEM to confirm the formation of Cu Core-Shell carbon hybrids and resulted in the average particle size of 351 nm, whereas XRD and XPS ensured the catalytic carbothermal transition of Cu2+ to Cu+/Cu particles. GC-MS and NMR analyzed the bio-oil samples and identified alcohols, alkanes, and esters in light oil. In contrast, carboxylic acids, ethers, esters, and phenols were key compounds in heavy oil.

Catalytic hydrothermal liquefaction of alkali lignin for monophenols production over homologous biochar-supported copper catalysts in water

Constructing an advanced catalytic system for the purposeful liquefaction of lignin into chemicals has presented a significant prospect for sustainable development. In this work, the catalytic process of mesoporous homologous biochar (HBC) derived from alkali lignin supported copper catalysts (Cu/HBC) was reported for catalytic liquefaction of alkali lignin to monophenols. The characterization results revealed HBC promoted the formation of metal-support strong interaction and the generation of oxygen vacancies, enhancing the acid sites of Cu/HBC. Under the optimal conditions (0.2 g alkali lignin, 280 °C, 0.05 g Cu/HBC, 6 h, 18 mL water), the monophenol yield reached 75.01 ± 0.76 mg/g, and the bio-oil yield was 57.98 ± 1.76%. The copious mesopores, high surface area, and rich acidic sites were responsible for the high activity of Cu/HBC, which significantly outperformed the controlled catalysts, such as HBC, commercial activated carbon (AC), and reported Ni/AC, Ni/MCM-41, etc. In four consecutive runs, the catalytic performance of Cu/HBC was only reduced by 3.65% per cycle. Interestingly, catechol was selectively produced with Cu/HBC, which provided an effective strategy for the conversion of G/S-type lignin to catechyl phenolics (C-type). These findings indicate that the Cu/HBC will be a promising substitution of noble metal-supported catalysts for conversion biomass into high value-added phenolics.

Microwave catalytic co-pyrolysis of sugarcane bagasse and Chlorella vulgaris over metal modified bio-chars: Characteristics and bio-oil analysis

Bio-char (BC) is a cheap, environmentally friendly and easy-to-produce material, which is widely used as pyrolysis catalyst. In this study, the modified catalysts (Fe/BC, Co/BC and Mg/BC) were prepared using BC produced by the co-pyrolysis of sugarcane bagasse and Chlorella vulgaris. The characterization of the modified catalysts showed that they had a higher surface area (SBET) and pore volume compared with BC. Besides, the influence of modified catalysts on co-pyrolysis was analyzed at different additions. Except for 10% Mg/BC, the catalysts effectively increased the average weight loss rate (Rv) and decreased the reaction time (ts) of co-pyrolysis at all additions, and 40% Fe/BC addition had the highest Rv and lowest ts. The catalyst addition increased the bio-oil yield of the co-pyrolysis, and the maximum bio-oil yield (25.94%) was obtained under 40% Mg/BC addition. Moreover, the catalysts not only facilitated the formation of hydrocarbons, but also suppressed the generation of amines/nitriles and acids/esters. After adding 40% Fe/BC, the hydrocarbons content reached the highest (26.01%), while the amines/nitriles content (3.23%) and acids/esters content (4.66%) reached the lowest. The results provided theoretical support for improving microwave pyrolysis characteristics and bio-oil quality using modified BC catalysts.

Sustainable production of aromatic-rich biofuel via catalytic co-pyrolysis of lignin and waste polyoxymethylene over commercial Al2O3 catalyst

Co-valorization of biomass and multiple solid wastes is essential to environment protection and energy security. Herein, aromatic-rich biofuel was produced from lignin and waste polyoxymethylene (POM) via catalytic co-pyrolysis process. Commercial and cheap γ-Al2O3 catalyst exhibited good catalytic performance. Series characterizations and bench-top pyrolysis experiments were conducted to illustrate the synergism between raw materials and the mechanism of aromatics formation. The TG analysis and thermodynamics calculation revealed that a remarkably positive synergistic effect existed between lignin and POM, which reduce the activation energies and make the reaction more conducive in terms of thermodynamics. Meanwhile, the yields of biochar and bio-oil increased considerably. Additionally, the operating conditions affected the product distributions significantly. The suitable mixing ratio of lignin to POM was around equal (5:5) with the bio-oil yield increased to 28.3 % and aromatic hydrocarbons selectivity increased to > 95 %. Moreover, POM, the precursor for alkylating reagents and hydrogen donors, could promote the deoxygenation reactions of phenolic intermediates and result into aromatic hydrocarbons. The acid sites of γ-Al2O3 promoted series secondary cracking reactions (alkylation, deoxygenation), and thus improved bio-oil quality. Finally, the stability test showed that commercial γ-Al2O3 catalyst was slightly deactivated after 4 cycles because of coke deposits and acid sites loss.

Catalytic pyrolysis of olive pomace for biofuel production: Application of metal oxide-modified zeolite catalysts

Catalytic pyrolysis of olive pomace (OP) was studied in a quartz fixed bed reactor at 500 °C. Due to the presence of high amounts of oxygenated components (OC) in bio-oil, the aim of this research was upgrading of bio-oil to valuable biofuel. Synthesized MgO, CaO, NiO, and Co3O4 modified zeolite catalysts were examined at several catalysts to biomass (C/B) ratios (0.2, 0.3, 0.4, 0.5, and 5). Different characterization method including Brunauer–Emmett–Teller (BET) and N2 adsorption/desorption isotherm analysis, X-ray diffraction (XRD), scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) were performed to identify the synthesized catalysts. Results showed that the bio-oil yield decreases in catalytic pyrolysis. All metal-modified zeolite catalysts reduce the content of OC as undesirable compounds and increase aromatic and aliphatic hydrocarbons as valuable products in the bio-oil. Using MgO, CaO, NiO and Co3O4 supported on zeolite catalysts, increase notably the aromatic hydrocarbons content to 82.43%, 79.10%, 79.91%, and 79.19%, respectively at C/B ratio of 5. At the C/B ratio of 5, the elimination rate of total OC for MgO/zeolite and CaO/zeolite catalysts reach to 90.56% and 86.94%, respectively. For NiO/Zeolite and Co3O4/zeolite, this value is equal to 89.30% and 86.39%, respectively.

Production of Antioxidant Additives and High-quality Activated Biochar from Pyrolysis of Argan Shells

An integral valorization route based on a pyrolysis process has been proposed to find sustainable applications for argan shells focused on the simultaneous production of activated biochar and antioxidant additives from bio-oil. The bio-oil obtained in the pyrolysis process was furtherly upgraded (hydrothermal treatment and extraction process) to obtain antioxidant additives. On the other hand, the biochar obtained in the pyrolysis was used as a feedstock to produce high-quality activated biochar (by physical activation with CO2). The increase in the pyrolysis temperature (350–550 °C) hardly affected the pyrolysis products distribution (biochar yields of 28–34 wt.% and bio-oil yields between 51 and 55 wt.%), but it led to a slight decrease in the content of phenolic monomers extracted from bio-oil (from 63 wt.% at 350 °C to 53 wt.% at 550 °C). When these extracted fractions were blended with biodiesel (<1 wt.%), improvements of up to 300% in biodiesel oxidation stability were attained. The hydrothermal treatment of the bio-oil did not show noteworthy effects either on the production or antioxidant performance of the extracted fractions if compared with the fractions extracted from the raw bio-oil. Regarding the valorization of argan shells biochar, the activated biochar prepared from it showed considerable potential as an adsorbent material for CO2 (125 mg of CO2 per g of the activated biochar) or phenols (complete removal of 99.6% in 4 h of contact time). It was characterized by a high BET surface area (up to 1500 m2/g), a high carbon content (up to 95 wt.%), low ash content (around 2 wt.%), and a pH of around 8.

Taguchi Optimization on the Biooil Extraction from Fresh Water Algae (Spirogyra) Using Soxhlet Apparatus

The present investigation is aimed at maximizing the biooil yield (BOY) from the algal species Spirogyra by solvent extraction method with a nonpolar solvent n-hexane using a Soxhlet apparatus. Also, this present work is aimed at acquiring optimal physiochemical properties such as kinematic viscosity and iodine value of the biooil produced from the algae. To carry out this work, the Taguchi technique with the L9 orthogonal array (OA) was used. With the L9 OA, nine sets of experiments were directed as per the design matrix, and the results were analyzed using the Taguchi method with the help of Minitab 16 software. The results generated from this optimization process showcased that the BOY from the Spirogyra was found to be a maximum of 26.86% with the particle size (PS) being 0.462 μm, the response time (RT) of 60 minutes, the solvent ratio (SR) of 1 : 10, and the extraction temperature (ET) of 75°C. The optimal set of input parameters for the optimal output response kinematic viscosity of 1.92 mm2/s was found to be achieved with the PS being 0.462 μm, 60 minutes of RT, the SR of 1 : 15, and the ET of 75°C. Similarly, the optimal set of input parameters for the optimal output response iodine value was found to be at 0.322 μm PS, 120 minutes of RT, an SR of 1 : 5, and an ET of 75°C. The signal-to-noise ratio (SNR) for the output responses exposed that the PS exhibited a major impact on the BOY and kinematic viscosity and the contribution levels of 76.68 and 51.7%, respectively.

Machine Learning Model Insights into Base-Catalyzed Hydrothermal Lignin Depolymerization.

Lignin, an abundant component of plant matter, can be depolymerized into renewable aromatic chemicals and biofuels but remains underutilized. Homogeneously catalyzed depolymerization in water has gained attention due to its economic feasibility and performance but suffers from inconsistently reported yields of bio-oil and solid residues. In this study, machine learning methods were used to develop predictive models for bio-oil and solid residue yields by using a few reaction variables and were subsequently validated by doing experimental work and comparing the predictions to the results. The models achieved a coefficient of determination (R2) score of 0.83 and 0.76, respectively, for bio-oil yield and solid residue. Variable importance for each model was calculated by two different methodologies and was tied to existing studies to explain the model predictive behavior. Based on the outcome of the study, the creation of concrete guidelines for reporting in lignin depolymerization studies was recommended. Shapley additive explanation value analysis reveals that temperature and reaction time are generally the strongest predictors of experimental outcomes compared to the rest.

Optimization and production of renewable fuels from waste cooking oil and low-density polyethylene: Evaluating fuel properties and techno-economic feasibility of diesel replacement

Pyrolysis of waste cooking oil (WCO) and plastics have caught the eye of contemporary researchers and industrialists, as valuable fuels can be produced from these wastes. However, process parameters such as feedstock blend ratio and temperature have to be optimized to obtain high-energy fuels at low-energy supply. Hence, this study aims to provide an insight into the optimization and techno-economic feasibility for the production of diesel-equivalent fuel from WCO and LDPE. A full-factorial design of experiments was delineated between six temperatures and seven feedstock blend ratios to compare oil yields. An optimum bio-oil yield of 65% was observed at 500 °C and 2:1 (WCO:LDPE) blend-ratio. Further, pyrolyzed WCO and equal blends of WCO and LDPE were tested for fuel properties, and these confirmed to Grade No. 2 and Grade No. 4 diesel–fuel as per ASTM standards respectively. A techno-economic analysis indicated a payback period of <14 months for both the fuels.

Bio-oil and biochar production from Ageratum conyzoides using triple-stage hydrothermal liquefaction and utilization of biochar in removal of multiple heavy metals from water

Production of low-cost biomass and its utilization for producing cost effective and eco-friendly bioenergy as well as for removing heavy metals from water can be explored as an approach to meet the sustainable development goals. In light of the above-mentioned study, hydrothermal liquefaction (HTL) of Billy goat weed (BGW; Ageratum conyzoides) was carried out to produce bio-oil. In addition, the residual biochar from the HTL process was activated to obtain Act-BC and was further modified to produce MnO2-loaded biochar (Act-BC@MnO2-25%). The HTL of BGW was done at three different temperatures, i.e., 250 °C, 350 °C and 450 °C in a high-pressure batch reactor to maximize the bio-oil yield. Also, two different HTL methods i.e., single-stage HTL and triple-stage HTL of BGW were compared and discussed in detail. The bio-oil obtained via the triple-stage HTL was rich in carbon, hydrogen, and nitrogen. It also showed a higher heating value (HHV) and bio-oil yield (46%) than the single-stage. The residual biochar obtained at 450 °C (Act-BC) and MnO2 modified (Act-BC@MnO2-25%) were then tested to adsorb multiple heavy metal (i.e., Pb(II), Cd(II), Cu(II), and Ni(II)) from water. The kinetics data obtained from the adsorption experiment with Act-BC@MnO2-25% were well fitted to PSO kinetics model. The isotherm data were well aligned with the Langmuir model; the adsorption capacity of Act-BC@MnO2-25% was estimated to be 198.70 ± 11.40 mg g−1, 93.70 ± 6.60 mg g−1, 78.90 ± 7.20 mg g−1 and 30.50 ± 2.10 mg g−1 for Pb(II), Cd(II), Cu(II), and Ni(II), respectively. Furthermore, Act-BC@MnO2-25% remained active for metal ions absorption even after six consecutive uses. The result obtained from this study clearly demonstrates that the triple-stage HTL of BGW is a promising technology to achieve both remediation of metal-contaminated water and production of bioenergy.

Characterization of bio-oil production by microwave pyrolysis from cashew nut shells and Cassia fistula pods

Abstract In this study, the production of bio-oil by pyrolysis with microwave (MW) heating was tested experimentally. Two magnetrons with a total MW power of 1,600 W were used in the pyrolysis setup. The electric field strength was 185.38 V·m−2 at an MW frequency of 2.45 GHz. Cashew nut shells (CNS) or Cassia fistula pods (CFP) were pyrolyzed at 400°C, 500°C, or 600°C, with biomass-to-activated carbon ratio set at 70:30, 80:20, or 90:10. The largest yield of bio-oil was found for CNS at 600°C, and for CFP at 500°C, both with 90:10 ratio, achieving, respectively, 20.0% and 15.8% yields. When the bio-oil yields from CNS and CFP at 90:10 ratio and 400–600°C were analyzed with gas chromatograph-mass spectrometer, the components found included acids, esters, ketones, furans, pyrans, guaiacol, syringol and phenols, and phenolic derivatives were the dominant type of compounds. There were 23.56% and 13.23% phenolic derivatives, respectively, in the bio-oils from CNS (at 500°C) and from CFP (at 400°C). An analysis with Folin–Ciocalteu reagent of the phenolic contents in bio-oils gave the respective ranges 146.83–164.83 mg·GAE·g·DW−1 and 39.34–45.91 mg·GAE·g DW−1 for CNS and CFP (both run with 90:10 ratio).

Modelling and simulation of fast pyrolysis of pomace from three-phase olive mill targeting optimal yields of pyrolysis products

Biomass can be transformed into useful bioproducts (biofuels, biomaterials) through its thermochemical conversion. This study concerns modeling and simulation of fast pyrolysis of olive pomace from three-phase olive mill using Super Pro Designer (SPD) software, which was selected because of its vast databank of specific chemical compounds as well as specific unit operations specifically designed for modeling and simulation of biological, physical and chemical processes. The simulation was carried out at pyrolysis temperatures ranging from 400 to 675 °C and residence times varying between 0.1 and 15s. Simulation results indicate that fast pyrolysis yielded maximum bio-oil yield of 23.72% at 650 °C and a residence time of 0.1s, and maximum syngas yield of 41.17% at 675 °C and a residence time of 15s. Predicted product yields were in accordance with experimental data collected from the literature, with relative errors in the range of 9%, which may be due to variable feedstock properties. The developed model provides very useful information on olive pomace fast pyrolysis conditions.

Red mud catalysts for hydrothermal liquefaction of alkali lignin: Optimization of reaction parameters

The aromatic enrichment structure of lignin shows its great potential for valuable chemicals, which could be a substitution for petrochemical raw materials. However, the selective breaking of its macromolecular structure is a key challenge in lignin valorization. This study examined hydrothermal liquefaction of alkali lignin with Zr, Mo, and Ce-impregnated red mud catalysts to achieve the maximum liquefaction and break down the sub-aromatic units into selective phenolics. 10 wt% Mo and 10 wt% Ce/RM exhibited the effective liquefaction tendency in ethanol solvent. With a C/F ratio of 1:5, the maximum bio-oil yield (81.8 wt%) was obtained with (5 wt%) Mo–Ce/RM catalyst, and maximum conversion (91.6%) was achieved with a 1:2 C/F ratio in 50E: 50W co-solvent. However, the C/F (1: 10) was found to be efficient towards the selective breaking of alkali lignin into guaiacol compounds with 65.4 area% selectivity of vanillin. The FTIR and 1H NMR analysis showed the actual breaking of lignin sub-aromatic structure into monomeric compounds. The results of GPC analysis validate the cleavage of lignin's structure with a significant reduction in the molecular weight of lignin from ∼28400 gm/mol to ∼485 gm/mol. The catalyst was highly recyclable as it maintained remarkable activity up to two successive catalytic cycles.