Maximum Bio-oil Yield Research Articles

Improvement of Properties of Bio-Oil from Biomass Pyrolysis in Auger Reactor Coupled to Fluidized Catalytic Bed Reactor

The goal of this research work was to investigate the improvement of bio-oil issued from beechwood biomass through catalytic de-oxygenation. Pyrolysis was conducted in an auger reactor and the catalytic treatment was performed in a fluidized catalytic bed reactor. Lab-synthesized Fe-HZSM-5 catalysts with different iron concentrations were tested. BET specific surface area, BJH pore size distribution, and FT-IR technologies were used to characterize the catalysts. Thermogravimetric analysis was used to measure the amount of coke deposited on the catalysts after use. Gas chromatography coupled to mass spectrometry (GC-MS), flame ionization detection (GC-FID), and thermal conductivity detection (GC-TCD) were used to identify and quantify the liquid and gaseous products. The pyrolysis temperature proved to be the most influential factor on the final products. It was observed that a pyrolysis temperature of 500 °C, vapor residence time of 18 s, and solid residence time of 2 min resulted in a maximum bio-oil yield of 53 wt%. A high percentage of oxygenated compounds, such as phenolic compounds, guaiacols, and the carboxylic acid group, was present in this bio-oil. Catalytic treatment with the Fe-HZSM-5 catalysts promoted gas production at the expense of the bio-oil yield, however, the composition of the bio-oil was strongly modified. These properties of the treated bio-oil changed as a function of the Fe loading on the catalyst, with 5%Fe-HZSM-5 giving the best performance. A higher iron loading of 5%Fe-HZSM-5 could have a negative impact on the catalyst performance due to increased coke formation.

The effects of voltage, particle size, and temperature on bio-oil yield produced via pyrolysis of Sargassum sp

Abstract The energy demand is increasing due to population growth and economic activities. Currently, global energy production, including in Indonesia, heavily relies on fossil fuels like petroleum, which are depleting day by day. One renewable energy form for the future is bio-oil, produced through pyrolysis using biomass as raw material. Macroalgae biomass, particularly Sargassum sp., is a sustainable and net-zero emission source for renewable energy. Pyrolysis is a promising technique to convert Sargassum sp. into high-value charcoal, gas, and bio-oil with less than 20% moisture content. Experimental research was conducted using a simple slow pyrolysis setup, using Sargassum sp. from Pantai Trenggole, Gunung Kidul. Proximate analysis showed Sargassum sp. contains ash, water, volatile matter (Vm), fixed carbon (FC), and calorific value of 15.428%, 6.032%, 40.222%, 38.318%, and 2161.758 cal/g respectively. Regarding the experiment results, the maximum bio-oil yield was obtained at 200 V with a yield of 27.289%. For the particle size variable, the maximum bio-oil yield was achieved with particles of 10-40 mesh, resulting in 27.289% yield. Regarding the temperature variable, the highest bio-oil yield was obtained at 600 °C with a yield of 29.362%.

Microwave catalytic co-pyrolysis of microalgae and high density polyethylene over activated carbon supported bimetallic: Characteristics and bio-oil analysis

Three activated carbon (AC) supported bimetallic catalysts (Ce-Fe/AC, Ce-Ni/AC, Ce-Cu/AC) were prepared, and the catalysts' impacts on the microwave co-pyrolysis of Chlorella vulgaris (C. vulgaris) and high density polyethylene (HDPE) (mixing ratio of 1:1, C1HP1) were explored. The findings indicated that the catalysts promoted the co-pyrolysis of C1HP1 substantially at 40 % and 50 % additions. The minimum reaction time (2945 s) was observed at 40 % Ce–Fe/AC. Compared to the C1HP1 group, Ce-Fe/AC groups exhibited a pronounced promotional impact on bio-oil production, with the maximum bio-oil yield (25.8 %) catalyzed by 30 % Ce–Fe/AC. Furthermore, the catalyst's high hydrogenation activity and deoxygenation promoted the formation of H2O, NH3 and HCN, achieving over 40 % efficiencies in deoxygenation and denitrification for bio-oil. 40 % Ce–Cu/AC exhibited superior performance with the highest hydrocarbon (67.43 %) and aromatic hydrocarbon content (50.75 %), as well as leading deoxygenation (44.38 %) and nitrogen removal (58.63 %) efficiency among the AC supported bimetallic catalysts.

Chromium-extracted aluminum catalyst for co-pyrolysis of cotton fabric waste and polypropylene plastic waste to bio-oil

Heterogeneous catalysts of chromium-extracted aluminum (CE) were prepared and used to produce bio-oil from the co-pyrolysis of cotton fabric waste (CFW) and polypropylene waste (PPW). The catalysts were synthesized via wet impregnation at 5–20 wt% catalyst loading and calcined at 600 °C for 5 h. The co-pyrolysis was conducted in a fixed-bed reactor at 500 °C for 1 h with 1:1 CWF/PPW ratio and 1:1 catalyst/feedstock ratio. The physical and chemical properties of the catalysts and bio-oil were characterized by several techniques such as Brunauer–Emmet–Teller, scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, temperature-programmed desorption and gas chromatography-mass spectrometry. Investigations into the effects of metal loadings revealed that the 15CE catalyst was the most active, achieving a maximum bio-oil yield of 76.4 % and producing valuable chemical compounds like hydrocarbons, alcohols, phenols, and furans. The XRD of 15CE catalyst confirmed the presence of chromium oxide and assigned to the rhombohedral phase of the crystal lattice. BET indicated 15CE has the largest surface area (50.4 m2/g) among the CE catalysts which contributed to its high activity. The SEM revealed CE catalysts at different metal loadings contain irregular shapes and sizes with a rough surface texture. The NH3-TPD profiles indicated alterations in acid site distribution due to the interaction between the introduced Cr metal and EA. The 15CE catalyst also demonstrated significant reusability, maintaining performance after two regeneration cycles. These results confirm the potential of CE catalysts in enhancing bio-oil production from CFW and PPW.

Distribution and characterization of products obtained from pyrolysis of cooked food waste- Impact of heating rate

This work offers a comprehensive investigation of the pyrolysis products—liquid, gas, and solid derived from cooked food waste (CFW) at different heating rates (15–100 °C/min). The heating rate significantly influenced the yield of pyrolysis products. The maximum yield of bio-oil (oil + aqueous) was achieved at a heating rate of 50 °C/min, py-gas at 100 °C/min, and biochar at 15 °C/min. The yields were 34 wt% for bio-oil, 30 wt% for py-gas, and 32 wt% for biochar. Analysis of the bio-oil revealed significant proportions of fatty acids (Methyl-methyltetradecanoate) and esters (Oleic acid ethyl ester), constituting 25 %, and 26 % at 15 °C/min but declining with increasing heating rates. Another ester (9-Octadecenoic acid methyl ester) was found across all heating rate with highest concentration of 33 % at 100 °C/min. Aliphatic hydrocarbons (Octane, Dodecene, Heptadecane, Tetradecyne, Undecane, Dimethylhepta-1,3-triene, Tetradecane, Nonadecane), constituted highest concentration of 12 % at 25 °C/min and aromatic hydrocarbons (Toluene) showed maximum presence of 4 % at 50 °C/min. The aqueous phase showcased cyclic nitrogenated compounds (Piperidine), anhydrosugars (DGP), and furanics (Furanmethanol), with the highest concentrations of 46 %, 12 %, and 38 %, respectively observed at 100 °C/min. Instantaneous py-gas analysis indicated an elevated presence of CO2 and CO in the initial pyrolysis stages (up to 70 min) followed by higher H2 in the latter stages (>70 min). While increasing heating rates (15–100 °C/min) boosted cumulative fractions of CO2 and CO, the highest H2 fraction was observed at 50 °C/min. The proximate and ultimate analysis of biochars indicated increased ash, fixed carbon, HHV and H/C compared to raw CFW. The surface area and morphology were positively influenced by an increase in heating rate, resulting in a microporous biochar having maximum surface area of 340.6 m2/g at 50 °C/min.

Hydrogen peroxide assisted oxidative liquefaction of alkaline lignin over cobalt-nickel loaded zirconia catalysts

Research toward the oxidative fractionation of lignin is gaining attention due to the selective breaking of a sub-aromatic unit of lignin's complex structure into monomeric phenolic. This study aims to investigate the liquefaction tendency of alkaline lignin by screening the synergistic effect of Co and Ni loaded on synthesized (syn) ZrO2 catalyst under the applied mild oxidative reaction conditions of molecular oxygen and hydrogen peroxide. Compared to the non-catalytic reaction (38.1 wt%), a significant improvement in the bio-oil yield (53.7 wt%) was obtained with the 5Co–5Ni/ZrO2-syn catalyst under the oxidative condition of molecular oxygen. However, only 44.3 wt% bio-oil was observed with commercial (com) 5Co–5Ni/ZrO2-com catalyst. The synergistic study of Co and Ni metal exhibited a diverse impact on the fractionation of lignin into respective product yields (bio-oil, gas, and char). Notably, adding a catalytic amount of hydrogen peroxide showed a remarkable improvement in liquefaction. The maximum bio-oil yield (72.1 wt%), and a maximum conversion (77.9%) were noticed with 0.5 mL H2O2 at 120 °C/30 min under the atmospheric molecular oxygen. The GC-MS analysis of bio-oil (5Co–5Ni/ZrO2-syn-HP) attributed to a high quantity of guaiacyl phenolic with a maximum proportion of benzaldehyde-3-hydroxy-4-methoxy (65.3%). The 5Co–5Ni/ZrO2-syn catalyst was also examined for the three catalytic cycles, which did not show any significant loss in product yield.

Optimized catalytic stepwise pyrolysis for converting cotton straw into hydrocarbon-rich bio-oil in N2 and CO2

Stepwise pyrolysis is recognized as a promising method in converting biomass into sustainable bio-oils. However, a systematic study on the stepwise parameters (e.g., low- and high-pyrolysis temperatures, duration, atmosphere) is still lacking. Herein, the stepwise catalytic fast pyrolysis (CFP) of cotton stove over ZSM-5 was conducted, aiming to reveal the impact of aforementioned parameters on bio-oils production. Results showed that the low-temperature pyrolysis benefitted the decomposition of biomass, while the high-temperature counterpart favored the upgrading of bio-oil. The combination of a low-temperature pyrolysis (400 ℃ for 2 min) and high-temperature pyrolysis (600 ℃ for 3 min) led to a satisfied hydrocarbons selectivity (35.8 area%) and bio-oil yield (11.4 wt%). This was superior to the one-step pyrolysis conducted at 600 ℃ for 5 min, which decreased the values to 32.2 area% and 11.2 wt%, respectively. The CO2 introduction into N2 atmosphere in stepwise pyrolysis further enhanced the hydrocarbon-rich bio-oil production, and a maximum bio-oil yield of 15.9 wt% was obtained in 100 vol% CO2, while the highest hydrocarbons selectivity of 51.8 area% was reached in 80 vol% CO2. This work confirmed the advantages of stepwise pyrolysis for producing high-quality bio-oils and provided a reference for pyrolysis in CO2 atmosphere.

Characterization and bio-oil analysis of microalgae and waste tires by microwave catalytic co-pyrolysis

Waste tires (WT) are difficult to degrade in natural conditions, but co-pyrolysis with other substances can release environmental pressure. Thus, microwave catalytic co-pyrolysis of WT and Chlorella vulgaris (CV) were studied. The effects of material mixing ratio, catalysts (NiO, CoO and CeO) and their addition amounts (5%, 10%, 15% and 20%) on the co-pyrolysis were analyzed. The results showed that bio-oil yield was boosted by co-pyrolysis and the maximum value (19.77%) appeared at C6W4 (CV:WT = 6:4). While adding 15%NiO, the maximum yield of bio-oil increased by 8.66%. Compared with CV pyrolysis alone, the deoxidation rate, denitrification rate, and desulfurization rate of C6W4 were as high as 44.57%, 59.82% and 52.59%, respectively. Catalysts improved the quality of bio-oil, the highest hydrocarbon content (58.3%) and denitrification rate (27.07%) were obtained at the 15%NiO. The highest aromatic hydrocarbon content (33.2%) and deoxygenation rate (10.31%) appeared in 15%CoO.

Characterization and mechanism elucidation of high-quality bio-oil production from co-pyrolysis of waste low-rank coal fines and de-oiled microalgae biomass using bimetallic (Cu-Cr) ZSM-5 catalyst

The present study provides a cleaner co-pyrolysis strategy for high-quality bio-oil production by utilizing low-cost residues such as low-rank coal (CL), de-oiled microalgae (ALG), and their blends (CLALG). The heavy metal-loaded Cu-Cr-ZSM-5 catalyst is synthesized by using ion-exchange method and investigated in the CL, ALG and CLALG pyrolysis bio-oil upgradation at different catalyst feed ratios (0.5:1, 1:1, 2:1). The synthesized catalyst was characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and brunauer-emmett-teller (BET) analysis. The synthesized catalyst is nano-crystalline of average size 7 nm. The microstructure of the synthesized catalyst shows stacked nanorods packing with connected intercrystal and intracrystal mesopores. The catalytic and non-catalytic pyrolysis of CL, ALG and CLALG are performed at 600 °C, 10 °C/min for 60 min. The non-catalytic ALG pyrolysis has shown maximum bio-oil yield (35.7%). The synergistic effect of nanorod morphology, active acid sites and excess mesoporosity of catalyst facilitates efficient deoxygenation, denitrogenation and aromatization of pyrolysis bio-oil with oxygen content from 2.1⎼3.1%, nitrogen content 3.5⎼5.1% and aromatic content 49.4⎼54.4% at catalyst feed ratio of 1:1. The maximum obtained higher heating value (HHV) of bio-oil from catalytic pyrolysis of CL (40.1 MJ/kg) followed by CLALG (38.6 MJ/kg) and ALG (36.5 MJ/kg) is very close to diesel oil with HHV (42⎼46 MJ/kg). Further, a co-pyrolysis mechanism is proposed to systematically investigate possible catalytic action sites to yield high-quality bio-oil. Thus, outcomes of the present study enrich information regarding catalyst development, catalyst feed interaction, and thermocatalytic cracking as emerging efforts towards industrial-scale upgradation of bio-oil to engine fuels.

Co-liquefaction of α-cellulose and phycocyanin: A preliminary study

Hydrothermal liquefaction (HTL) is an efficient technology for converting biomass to platform compounds. It has great potential for reducing the dependence on fossil fuels. The HTL of waste biomass has been extensively studied in recent years due to both its environmental and economic benefits. However, most woody waste contains a large amount of cellulose, and it is difficult to be sufficiently decomposed to valuable chemicals. Phycocyanin, a key component of algae, is easily degraded under high-temperature liquefaction conditions. In this work, focusing on bio-oil generation properties, the co-liquefaction characteristics and synergistic mechanisms of α-cellulose and phycocyanin were explored. The findings revealed a maximum bio-oil yield of 33.1 wt% under the optimal conditions (300 °C for 40 min), with a notable positive synergistic effect of 13.5 wt%. Chemical composition analysis indicated distinct compositional differences between the bio-oils derived from individual and dual feedstock. The amounts of pyridine and pyrimidine compounds increased due to the enhanced co-liquefaction. The results also highlighted the influence of temperature on the degree of conversion and product distribution. Finally, preliminary chemical reaction pathway was elucidated, underscoring the potential of integrating microalgae and woody biomass for enhanced bio-oil production.

Design expert based optimization of the pyrolysis process for the production of cattle dung bio-oil and properties characterization

This study aimed to optimize pyrolysis conditions to maximize bio-oil yield from cattle dung, a waste product of livestock practices. Pyrolysis of cattle dung was carried out in batch type reactor. The pyrolysis process was optimized using a central composite design in response surface methodology, with conversion parameters such as pyrolysis temperature, vapor cooling temperature, residence time, and gas flow rate taken into account. The cattle dung bio-oil was analyzed using gas chromatography/mass spectroscopy (GC/MS), an elemental analyzer, a pH probe, and a bomb calorimeter. Furthermore, the ASTM standard procedures were used to determine the bio-fuel characteristics. The optimized conditions were found to be a pyrolysis temperature of 402 °C, a vapor cooling temperature of 2.25 °C, a residence time of 30.72 min, and a gas flow rate of 1.81 l min−1, resulting in a maximum bio-oil yield of 18.9%. According to the findings, the yield of bio-oil was predominantly affected by pyrolysis temperature and vapor cooling temperature. Moreover, the bio-oil that was retrieved was discovered to be similar to conventional liquid fuels in numerous ways.

Valorization of low heavy metal-accumulating plants through catalytic hydrothermal liquefaction with attapulgite: Product characterization and migration behavior of heavy metals

Harmless treatment of heavy metal-accumulating plants is significant for further development and application of phytoremediation for contaminated soil remediation. In this study, hydrothermal liquefaction (HTL) of low heavy metal-accumulating plants (Jute, Solanum nigrum, and Sorghum) was conducted at different temperatures (280–360 °C) for bio-oil production. Attapulgite and Co/Attapulgite were prepared and tested in HTL process. The maximum bio-oil yield and higher heating value (HHV) was found to be 32.04% and 29.61 MJ/kg from HTL of Solanum nigrum with Co/Attapulgite at 300 °C. The improvement in quality of bio-oil was marked with decreased O/C content (0.26) and newly formed hydrocarbon fraction with the content of 6.24% with Co/Attapulgite catalyst. It was beneficial for immobilization of Mn, Zn and Cr in hydrochar with addition of catalyst. Notably, Mn and Cd were not detected in any bio-oil, and the proportion of Cr in the bio-oil obtained at 360 °C decreased to zero with Co/Attapulgite. XPS and XRD analysis indicated that Mn and Zn existed in the form of Mn3O4, Mn, ZnO and Zn(OH)2 in hydrochar. Finally, potential pathway of heavy metals migration-transformation behaviors during HTL was proposed.

Assessing coconut shell pyrolysis: Biomass characterization, activation energy estimation, and statistical analysis of operating conditions

This study experimentally investigates the conventional pyrolysis of green coconut shell (GCS) in a fixed-bed reactor, analyzing operational conditions and their impact on product yields using statistical methods. Comprehensive characterization of GCS highlighted an extractive content of 36.65 %, significantly influencing the pyrolysis activation energy. Statistical analysis revealed that temperature has a more pronounced effect on yield over particle size. Optimal pyrolysis conditions were identified at 773.15 K with a particle diameter of 1.3 mm, achieving a maximum bio-oil yield of 49.45 %, surpassing the reported in previous fixed-bed reactor studies. Bio-oil analysis indicated aldehydes, phenols, and esters predominance, with temperature as the primary factor influencing their formation. The study demonstrates the effectiveness of GCS pyrolysis in fixed bed reactors for converting waste into valuable products with potential applications as energy sources, as well as in the chemical and pharmaceutical industries, thereby reducing environmental impacts associated with improper disposal.

Production of bio-oil from Tung seed residues in a fluidized-bed reactor

The current paper presents research on bio-oil production from Tung seed residues fed at 500 g/h via fast pyrolysis in a fluidized-bed. The objective was to investigate the influence of temperature on bio-oil production in a pyrolysis process. Three portions Tung residues were studied, Tung seed outer shells (TO), Tung seed inner shells (TI), and pressed residues of oil seeds (RS), all having particle sizes of 0.150–0.500 mm. The process temperatures were 350–500 °C. The physical and chemical properties of pressed residue particles were characterized by ASTM standard methods. Bio-oil component identification was done using GC-MS. Experimentally derived data showed an optimal pyrolysis temperatures for all three types of Tung residues (TO, TI and RS) of 400 °C, yielding respective maximum bio-oil yields of 53.46, 52.81, and 62.85 wt% on a dry basis (db). Apart from having highest bio-oil yield, RS produced bio-oil with the highest carbon content, leading to its greatest lower heating value (LHV), 28.05 MJ/kg (db). The main bio-oil components were acids, nitrogen compounds, and hydrocarbons. Char yield was reduced with increased temperature. Tung seed outer shells produced the highest char level (39.26 wt%) while RS gave highest char quality in term of density and heating value.

Application of Central Composite Design in the Pyrolysis Process for Making Bio-Oil Based on Meranti Wood Sawdust (Shorea pinang)

Renewable energy sources are gaining importance to counteract the harmful effects of fossil fuel consumption on climate change. Among these sources, bioenergy is a viable option that can be derived from different forms of biomass and used as fuel for various purposes such as transportation, power generation, buildings, and industry. Meranti sawdust is a readily available biomass source in Indonesia that can be converted into bio-oil through pyrolytic processes. Therefore, this research aims to determine the impact of key parameters, including temperature, reaction time, and particle size, on the pyrolysis process and identify optimal yield conditions. The central composite design is the method used to determine the optimal value of the operating factors of the maximum yield of bio-oil. The results showed that the optimal conditions for the pyrolysis process are achieved at 377°C, 100 minutes of reaction time, and 0.46 mm particle size, yielding 41.48%.

Thermal liquefaction of olive tree pruning waste into bio-oil in water and ethanol with NaOH catalyst

In this study the effect of catalysts and solvents at varying temperatures on the production of bio-oil from olive tree pruning waste (OPW). The thermal liquefaction process was conducted at 200 °C, 225 °C, and 250 °C for 90 min, employing either water or ethanol as solvents, with alkaline catalysts (0.125 M, 0.25 M, and 0.5 M NaOH) introduced for the first time. Raw material, solid byproducts, and bio-oil samples underwent FTIR analysis for structural changes, TGA for proximate analysis, and GC-MS for bio-oil analysis. Results revealed that NaOH enhanced biomass conversion in water, yet didn't increase bio-oil yield, whereas in ethanol, biomass conversion was relatively lower, but bio-oil yield improved despite the adverse effects of catalyst. The highest biomass conversion (94 %) was achieved at 250 °C with 0.5 M NaOH, but the maximum bio-oil yield (25 %) occurred without a catalyst in water. Conversely, the highest bio-oil yield (55 %) was attained using ethanol without a catalyst at 250 °C.

Production of Biofuel by Catalytic and Non-Catalyst Pyrolysis of Plantain Stalk

The depletion of global fossil fuel reserves and environmental concerns associated with its production are driving the shift towards biomass as a renewable energy source, which can be converted into biofuels and biogas for diverse energy applications. Hence, we conducted pyrolysis experiments on plantain stalk samples to examine the impact of pyrolysis temperature and heating rate on product yields and their chemical compositions. Optimal conditions for maximum bio-oil yield (22%) were identified at a torrefaction pre-treatment temperature of 300℃. The highest biochar yield (16.88%) was achieved at 300℃, while the highest biogas yield (61.85%) was observed at 150℃. Detailed elemental, proximate, and ultimate analyses of the bio-oil were performed, and its chemical composition was analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). The chromatographic and spectroscopic studies confirmed that bio-oil derived from plantain stalk is a promising renewable fuel and chemical feedstock, indicating its potential in sustainable energy applications.

Waste animal fat with hydrothermal liquefaction as a potential route to marine biofuels.

Unused animal waste rendered fat is a potential feedstock for marine biofuels. In this work, bio-oil was generated using hydrothermal liquefaction (HTL) of nitrogen-free and low sulfur rendered bovine fat. Maximum bio-oil yield of 28 ± 1.5% and high heating value of 38.5 ± 0.16 MJ·kg‒1 was obtained at 330 °C at 50% animal fat solid load and 20 min retention time. The nitrogen and sulfur content were negligible, making the produced bio-oil useful marine biofuel, taking into account current stringent regulations on NOx and SOx emissions. The economic analysis of the process, where part of the bovine fat waste is converted to the bio-oil and the semi-solid residues can be used to supply the heat demand of the HTL process and alternately generate electricity, showed that our process is likely to generate a positive profit margin on a large scale. We also showed the growing economic importance of electricity in the revenues as commercial production becomes more energy efficient.

Optimization of bio-oil extraction from Chlorella biomass via a green approach to obtain algal-based Di-ethyl phthalate.

This study focuses on determining the optimum external operating parameters of algal cell lysis for extraction of bio-oil from Chlorella biomass. Response surface methodology has been applied to a regression analysis model for optimizing solvent ratios, i.e., ethyl acetate to ethanol (E.A.:E) ratio for maximum extraction of bio-oil and aqueous deep eutectic solvent to biomass (aDES:biomass) ratio for algal pretreatment for the enhanced yield of bio-oil. Optimized process conditions were 15min of homogenization combined with ultrasonication (hybrid method). The aDES:biomass ratio of 8.25 caused the highest cell disruption efficiency to liberate bio-oil from encapsulated cells. The solvent ethyl acetate to ethanol ratio (E.A.:E) was optimum at 0.8 for maximum extraction of bio-oil, and studies indicated a maximum bio-oil yield of 94.0% using this hybrid pretreatment process combined with ultrasonication and homogenization. The GC-MS characterization technique was used to analyze the bio-oil, which showed it consisted of 67.93% Di-ethyl phthalate (DEP) and 32.07% esters compounds (C12-C40 hydrocarbons range). The produced DEP from Chlorella biomass using this sustainable green approach is very promising. The estimated cost was around Rs 49 per gm (equivalent to Rs 664.56 for 13.58 gm), which indicates the potential for a cost-effective method to produce pure DEP from Chlorella biomass.

Hydrothermal liquefaction of Elaeis guineensis trunks: Lessons learned from a case study in Guatemala

The oil palm industry has been under public scrutiny during the last decades due to environmental and social issues related to its practices. Oil palm (Elaeis guineensis Jacq.) trunks (OPTs) are of special interest as they are left idle in the field after the replanting process which is performed every 25 years. This common practice results in harvesting challenges, phytosanitary risks, and a loss of bioenergy potential. Due to their high moisture content and fibrous nature, OPTs present a problem for traditional conversion processes that require a dry and homogeneous material. This study evaluates the feasibility of converting OPTs into a bio-crude oil and biochar to increase the sustainability of the oil palm sector. To date, research efforts have primarily focused on hydrothermal liquefaction (HTL) of OPT without catalysts, resulting in a limited understanding of the potential of OPTs. Thus, the main novelty of this work is the evaluation of the effects of catalyst dosage (0–5 wt%) on the bio-oil yield, reaction temperature (260–300∘C), and residence time (15–60 min) using a half-fraction experimental design methodology. For this, OPTs extracted from two plantations in Guatemala were used. The maximum bio-oil yield (26.77 ± 3.60 wt%) was found at 260∘C for 15 min and 5 wt% catalyst with a high heating value (HHV) of 19.29 ± 1.33 MJ kg−1. Nonetheless, the bio-oils produced without a catalyst at 300∘C and 15 min have higher HHV (27.63 ± 1.35 MJ kg−1) and are similar to Diesel fuel based on their H/C and O/C ratio. These results indicate that there is a potential trade-off between the bio-crude oil mass yield and HHV when using the catalyst.