Highest Bio-oil Yield Research Articles

Hydrothermal Liquefaction of Sugarcane Bagasse and Straw: Effect of Operational Conditions on Product Fractionation and Bio-Oil Composition

In the energy transition process, aiming for zero disposal and clean production in the elimination of waste is crucial; consequently, agricultural residues have significant potential for reduction in the use of fossil fuels. This study investigates the hydrothermal liquefaction (HTL) of sugarcane bagasse (BSC) and straw (SSC), examining the products’ distribution and bio-oil composition relative to the reaction conditions. The experiments used a 23 factorial design, evaluating the temperature (300–350 °C), constant heating time (0–30 min), and the use of the K2CO3 concentration as the catalyst (0–0.5 mol/L−1). The main factor affecting the biocrude yield from BSC and SSC was the use of K2CO3. Statistically significant interaction effects were also observed. Milder conditions resulted in the highest bio-oil yields, 36% for BSC and 31% for SSC. The catalyst had no impact on the biocrude production. The bio-oils were analyzed by GC/MS and FTIR; a principal component analysis (PCA) was performed to evaluate the samples’ variability. The FTIR highlighted bands associated with common oxygenated compounds in lignocellulosic biomass-derived bio-oils. The GC-MS results indicated a predominance of oxygenated compounds, and these were highest in the presence of the catalyst for both the BSC (90.6%) and SSC (91.7%) bio-oils. The SSC bio-oils presented higher oxygenated compound contents than the BSC bio-oils. Statistical analysis provided valuable insights for optimizing biomass conversion processes, such as determining the optimal conditions for maximizing product yields.

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%.

Optimization of bio-oil production parameters from the pyrolysis of elephant grass (Pennisetum purpureum) using response surface methodology

Abstract The need to increase bio-oil yield from biomass and enhance its fuel properties has driven research into optimizing the pyrolysis process. This study investigated the influence of three key process parameters—temperature, heating rate, and nitrogen flow rate—on the pyrolysis of elephant grass (Pennisetum purpureum) in a fixed-bed reactor. Response surface methodology was used to study the impact of the aforementioned variables on bio-oil yield to improve its production efficiency. Proximate analysis of the biomass revealed 79.24 wt% volatile matter, 14.22 wt% fixed carbon, and 5.86% ash, with ultimate analysis showing 45.44% carbon, 5.59% hydrogen, and 40.95% oxygen. The high volatile matter content and favourable carbon and hydrogen percentages indicate that elephant grass is a viable energy source due to its potential for high bio-oil yield and energy content. The resulting bio-oil exhibited a higher heating value of 20.9 MJ/kg, indicating its suitability for various heating applications. A second-order regression model was developed for bio-oil yield, with optimal conditions identified as a temperature of 550°C, a heating rate of 17°C/min, and a nitrogen flow rate of 6 ml/min. The study achieved an optimal bio-oil yield of 59.03 wt%, and the model’s high R² value of 0.8683 from analysis of variance analysis confirmed its predictive accuracy. This research highlights elephant grass as a sustainable feedstock for bio-oil production, offering valuable insights into optimizing pyrolysis conditions to enhance bio-oil yield, thus advancing biofuel technology.

Production of Bio-Oil from Sugarcane Bagasse through Hydrothermal Liquefaction Processes with Modified Zeolite Socony Mobil-5 Catalyst

In response to the increasing global demand for sustainable energy alternatives, this research explores the efficient conversion of sugarcane bagasse to bio-oil through hydrothermal liquefaction (HTL) processes with modified Zeolite Socony Mobil-5 catalysts (ZSM-5). The study systematically investigates the impact of feedstock quantity, reaction temperature, duration, and catalyst loading on bio-oil yield and quality. Optimisation experiments revealed that a feedstock amount of 10 grammes, an HTL temperature of 340 °C for 60 min and a ZSM-5 catalyst loading of 3 grammes resulted in the highest bio-oil yield. Furthermore, the introduction of Ni and Fe metals to ZSM-5 exhibited enhanced catalytic activity without compromising the structure of the zeolites. Comprehensive characterisation of modified catalysts using SEM-EDS, XRD, TGA, TEM, and FTIR provided insight into their structural and chemical properties. The successful incorporation of Ni and Fe into ZSM-5 was confirmed, highlighting promising applications in hydrothermal liquefaction. Gas chromatography–mass spectrometry (GC-MS) analysis of bio-oils demonstrated the effectiveness of the 2% Fe/ZSM-5 catalyst, highlighting a significant increase in hydrocarbon content. FTIR analysis of the produced bio-oils indicated a reduction in functional groups and intensified aromatic peaks, suggesting a shift in chemical composition favouring aromatic hydrocarbons. This study provides valuable information on HTL optimisation, catalyst modification, and bio-oil characterisation, advancing the understanding of sustainable biofuel production. The findings underscore the catalytic prowess of modified ZSM-5, particularly with iron incorporation, in promoting the formation of valuable hydrocarbons during hydrothermal liquefaction.

Biofuel from wastewater-grown microalgae: A biorefinery approach using hydrothermal liquefaction and catalyst upgrading

Third-generation biofuels from microalgae are becoming necessary for sustainable energy. In this context, this study explores the hydrothermal liquefaction (HTL) of microalgae biomass grown in wastewater, consisting of 30% Chlorella vulgaris, 69% Tetradesmus obliquus, and 1% cyanobacteria Limnothrix planctonica, and the subsequent upgrading of the produced bio-oil. The novelty of the work lies in integrating microalgae cultivation in wastewater with HTL in a biorefinery approach, enhanced using a catalyst to upgrade the bio-oil. Different temperatures (300, 325, and 350 °C) and reaction times (15, 30, and 45 min) were tested. The bio-oil upgrading occurred with a Cobalt-Molybdenum (CoMo) catalyst for 1 h at 375 °C. Post-HTL, although the hydrogen-to-carbon (H/C) ratio decreased from 1.70 to 1.38–1.60, the oxygen-to-carbon (O/C) ratio also decreased from 0.39 to 0.079–0.104, and the higher heating value increased from 20.6 to 36.4–38.3 MJ kg−1. Palmitic acid was the main component in all bio-oil samples. The highest bio-oil yield was at 300 °C for 30 min (23.4%). Upgrading increased long-chain hydrocarbons like heptadecane (5%), indicating biofuel potential, though nitrogenous compounds such as hexadecanenitrile suggest a need for further hydrodenitrogenation. Aqueous phase, solid residues, and gas from HTL can be used for applications such as biomass cultivation, bio-hydrogen, valuable chemicals, and materials like carbon composites and cement additives, promoting a circular economy. The study underscores the potential of microalgae-derived bio-oil as sustainable biofuel, although further refinement is needed to meet current fuel standards.

Unveiling sustainable synergy and ageing stability of bio-oils from cotton gin trash and plastic waste co-liquefaction for an integrated waste-to-energy solution

Co-liquefaction is an emerging technology aimed at enhancing bio-oil yield and quality, compensating for decrease in feedstock, increasing productivity, and adding revenue to bio-refineries. This study delves into the influence of plastic waste (PW) types during co-liquefaction with cotton gin trash (CGT) on the yield and quality of the produced crude oil. Various plastics, including PLA (polylactic acid), PVA (polyvinyl alcohol), PET (polyethylene terephthalate), LDPE (low-density polyethylene), HDPE (high-density polyethylene), PP (polypropylene), and PS (polystyrene), were investigated in a mixing ratio of 2:1 (CGT/plastic waste) at 320 °C and 2 hours in supercritical ethanol (ScEtOH), without catalyst, to produce energy-dense bio-oil under optimised conditions. The study presents the suitability of different types of plastic waste for co-feeding with CGT, along with their synergistic and antagonistic effects on product fraction yield (oil, solid, and gas), and oil energy yield. High bio-oil yields of 54.5 wt%, 53.7 wt%, and 43.1 wt% were achieved during co-liquefaction of CGT with PLA, PET and PVA, respectively. Bio-oil with the highest Higher Heating Values (HHV) was achieved through the co-liquefaction of CGT with PVA (30.6 MJ/kg) and PS (31.5 MJ/kg). The solid fractions obtained from co-liquefying CGT with PLA and PVA contained 46.9 wt% and 55.1 wt% carbon, respectively, making them potential sustainable sources for soil amendment. Furthermore, the bio-oils were characterised using gas chromatography-mass spectroscopy (GC-MS), two-dimensional nuclear magnetic spectroscopy-heteronuclear single quantum coherence (2D‐NMR-HSQC), elemental analysis, fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) to assess their quality and stability. Solid residues were characterised to understand the extent of plastic degradation and their suitable applications. The results indicate that the co-liquefaction of lignocellulosic biomass with plastics represents a viable and promising approach for improving bio-oil quality and extending its shelf life.

Study on the characteristics of microwave pyrolysis of pine wood catalyzed by bimetallic catalysts prepared with microwave-assisted hydrothermal char

Bimetallic hydrothermal char catalysts (Co-Ni/MHC, Fe-Co/MHC, Fe-Ni/MHC) were prepared through ionic hydrothermal methods and microwave high-temperature activation. During catalyst preparation, different metals synergistically promoted the formation of ordered carbon structures such as carbon nanotubes and carbon microspheres, respectively. Serving both as microwave absorbers and catalysts for the microwave pyrolysis of pine wood, the bimetallic catalysts exhibited distinct advantageous characteristics. Fe-Ni/MHC exhibited excellent microwave absorption properties and was able to assist the PW to heat up rapidly at a rate of 6.17 °C/s, benefiting from which PW achieved a high bio-oil yield of 44.0 % in the microwave-assisted catalytic pyrolysis process. Using Co-Ni/MHC as a catalyst resulted in bio-oil with up to 42.7 % styrene content and had good catalytic effects on the formation of CO and H2. This study provides a scientific reference for the application of hydrothermal treatment and microwave-assisted pyrolysis in biomass pyrolysis technology.

Lagerstroemia speciosa (Banaba) seed as a new and prospective bioenergy resource

Bio-oil, a highly valuable product obtained from biomass pyrolysis after proper up-gradation and refining, can be utilised in a variety of downstream applications which is gaining attention to the researcher from last few decades. Extraction and fractionation are two viable techniques to upgrade bio-oil those divide the complex mixture of bio-oil compounds into distinct fine chemicals and fractions enriched classes of chemical compounds. In the current investigation, a new biomass plant (Lagerstroemia speciosa) seed, commonly known as Banaba underwent thermo-chemical conversion at four terminal temperatures viz., 350 0C, 450 0C, 550 0C and 650 0C with a rate of heating 10 0C/min. The highest bio-oil yield (59.36 % out of that 41.68 % is of oil phase) was attained at pyrolysis temperature of 550 °C. The optimum condensable liquid (bio-oil) was collected and analysed. Properties of Banaba were investigated by physico-chemical, biochemical, ultimate analysis, TGA/DTG and FTIR analysis. Characterization of condensable liquid (bio-oil) was investigated by FTIR, NMR and GC-MS. Fuel property of the condensable liquid was further analysed through flash point, pour point, viscosity, Calorific value, and ultimate analysis. The Hydrogen/Carbon molar ratio (1.49) of the bio-oil was determined to be on a level with petroleum-based diesel. The oil derived from Banaba is found to have considerable fuel properties and may be substituted for commercial fuel with chemical modification or through blending with conventional diesel for utilization in IC engine which need to be addressed further.

Comprehensive utilization for hydrothermal conversion products of food waste

Hydrothermal conversion technology is a promising technique for resource utilization. In this study, the influence of reaction conditions on the distribution of hydrothermal conversion products was investigated, and the resource utilization methods of all components of hydrothermal conversion products were discussed. The results showed that the highest bio-oil yield was obtained at 310 °C, which was 36.75 %. The higher heating value and energy recovery rate of bio-oil can reach 39.68 MJ/kg and 78.55 % respectively. And it had great potential as an alternative fuel. When wheat seeds cultured by aqueous were diluted 100 times at 310 °C with GI ≥ 80 %, the phytotoxicity disappears. At this time, the contents of total nitrogen, total phosphorus, and total potassium were 1234.80, 150.34, and 1640.36 mg/L respectively, and the heavy metal content was lower than the national standard for foliar fertilizer. The optimal conditions for biochar to adsorb methylene blue were adsorbent dose 2 g/L, 180 rpm, temperature 70 °C, and time 120 min; The gas phase yield increased with the increase of temperature (0.15–7.45 %). The yield at 310 °C was 2.76 %. The main component of the gas phase was CO2, accounting for 93.71–97.92 %. The innovation of this study was that food waste can be converted into bio-oil through high-temperature hydrothermal reaction, achieving energy recovery. The aqueous phase product of hydrothermal conversion was used as water-soluble liquid fertilizer, achieving resource utilization. At the same time, the reaction was carried out under high temperature and pressure, which can completely kill pathogens in food waste and has extremely high biological safety.

Catalytic Pyrolysis of Biomass Waste Mixture over Activated Carbon and Zeolite Catalyst for the Production Bio Oil

Biomass waste is one of the promising resource for the production of bio oil. In this study, a mixture of biomass waste will be pyrolyzed in the presence of activated carbon and zeolite as the catalyst. The catalyst concentrations were varied at 2%, 4%, 6%, respectively. While, the pyrolysis process was carried out at 500°C, for 60 minutes, with a nitrogen flow of 3 L/min. The highest bio oil yield was obtained the pyrolysis process by using zeolite with 35% at 4% w/w of the catalyst concentration. The lowest acid number obtained was 42.92 on 4% zeolite catalyst with rice husk biomass as the raw material, the best viscosity was obtained on 4% activated carbon multi feedstock with a viscosity value of 4.96 cP. The best density was obtained in multi feedstock with 4% zeolite catalyst and rice husk with 4% zeolite of 0.996 g/mL.

Yield and distribution of products of lignin liquefaction catalyzed by molybdenum-vanadium-phosphorus heteropolyacids

ABSTRACT This paper focuses on the performance of Molybdenum-vanadium-phosphorus heteropolyacids (PMo12-xVx) with different V-doped amounts in catalyzing the conversion of lignin to bio-oil, and the distribution of liquefied products. Molybdenum-vanadium-phosphorus heteropolyacids (PMo11V1, PMo10V2, PMo9V3) with different amount (0, 2.5, 5, 10 wt%) were used to catalyze lignin liquefaction. The experimental results showed that PMo12-xVx could effectively catalyze the depolymerization of lignin to bio-oil, and the doping amount of the V atom in PMo12-xVx affects the distribution of lignin depolymerization products. The highest bio-oil yield (53.62wt%) and conversion (57.83wt%) could be obtained from lignin liquefaction at 2.5 wt% PMo9V3. With the increase of PMo12-xVx V-atom doped amount, the content of aliphatic hydrocarbons increased from 3.14% to 40.58%, the content of vanillin increased from none to 8.9%. Based on the analysis of bio-oil, FT-IR data, and DFT simulation results, it was found that the selective cleavage of the Cα-Cβ bond and the ring-opening of the carbon at the methyl end of lignin were the main reasons for the high yield of vanillin and aliphatic hydrocarbons during the depolymerization of lignin catalyzed by PMo12-xVx. Finally, a possible reaction pathway for the PMo12-xVx-catalyzed depolymerization of lignin to vanillin and aliphatic hydrocarbons was proposed.

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.

Effects of mild acid pre-treatment on the co-pyrolysis behaviour of biosolids and wheat straw

Co-pyrolysis of biosolids (BS) and wheat straw (WS), as well as their treated variants, was performed in a fluidised bed reactor at 500 ℃. Under mild acid pre-treatment conditions (3% H2SO4 and 25 ℃), demineralisation was the dominating effect of pre-treatment on BS, while it was hemicellulose hydrolysis for WS. Consequently, the co-pyrolysis of raw biosolids (RBS) or treated biosolids (TBS) with raw wheat straw (RWS) or treated wheat straw (TWS) had varying effects on product distribution and product compositions. The co-pyrolysis of RBS+RWS gave the lowest bio-oil yield (36.3 wt%) and highest gas yield (23.1 wt%). In contrast, the highest bio-oil yield (45.8 wt%) and lowest gas yield (14.4 wt%) occurred during the co-pyrolysis of TBS+TWS. The degree of synergy in product distribution was strongest in TBS+RWS followed by RBS+RWS and was weakest in TBS+TWS, demonstrating the catalytic effect of inherent minerals on organic matter devolatilisation and char cracking reactions during co-pyrolysis. Biosolids pre-treatment alone performed competitively with BS co-pyrolysis alone with respect to enhancement in biochar properties producing biochar having 15–18 MJ/kg calorific value, 43–51 wt% carbon content, 0.7–1.0 fuel ratio, ⁓30% organic matter retention, and 27–41 wt% ash content. However, combining BS co-pyrolysis and pre-treatment gave the lowest reduction in biochar total heavy metal concentration. Furthermore, bio-oil compositions were influenced by pre-treatment and/or co-pyrolysis, increasing the yield (area%) of phenols to 25.4%, furans to 24.8%, anhydrosugars to 7.8%, and aromatic hydrocarbons to 20.6%. Lastly, pre-treatment alone weakened gas production while co-pyrolysis combined with pre-treatment impacted the pyrolysis gas profile, switching between light hydrocarbons and carbon oxides (CO and CO2). Overall, co-pyrolysis and pre-treatment can each be a standalone strategy for enhancing BS pyrolysis; however, their combination produced greater synergy for generating high value products.

Physicochemical synergistic effect of microwave-assisted Co-pyrolysis of biomass and waste plastics by thermal degradation, thermodynamics, numerical simulation, kinetics, and products analysis

Understanding the physicochemical synergistic effect of microwave-assisted co-pyrolysis (MACP) of biomass and waste plastics is crucial for efficient conversion and improving the quality of bio-oil. Thermal degradation, thermodynamics, and numerical simulation of co-pyrolysis of the corncob (CC) and polystyrene (PS) were conducted. Results showed that the co-pyrolysis of CC and PS had a positive physical synergistic and compatible effect in reducing energy consumption and accelerating reaction rate. The reaction kinetics analysis and pyrolysis products analysis found that the co-pyrolysis of CC and PS had a positive chemical synergistic effect. The co-pyrolysis both effectively reduced the pyrolysis activation energy and improved the yield and quality of bio-oil. Significantly, the sample of CC/PS (1:2) had the highest yield of bio-oil (52.3 wt%) and the highest relative content of aromatics (95.0 area%) in co-pyrolysis, while 450 °C was the most ideal pyrolysis temperature. This work indicated that the MACP of CC and PS showed a positive physicochemical synergistic effect, and provided theories and approaches for the production of bio-oil from the biomass and waste plastics by MACP.

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.

Fractional condensation of bio-oil vapors from pyrolysis of various sawdust wastes in a bench-scale bubbling fluidized bed reactor

The use of lignocellulosic waste as an energy source for substituting fossil fuels has attracted lots of attention, and pyrolysis has been established as an effective technology for this purpose. However, the utilization of bio-oil derived from non-catalytic pyrolysis faces certain constraints, making it impractical for direct application in advanced sectors. This study has focused on overcoming these challenges by employing fractional condensation of pyrolytic vapors at distinct temperatures. The potential of five types of sawdust for producing high-quality bio-oil through pyrolysis conducted with a bench-scale bubbling fluidized bed reactor was investigated for the first time. The highest yield of bio-oil (61.94 wt%) was produced using sample 3 (damaged timber). Remarkably, phenolic compounds were majorly gathered in the 1st and 2nd condensers at temperatures of 200 °C and 150 °C, respectively, attributing to their higher boiling points. Whereas, carboxylic acid, ketones, and furans were mainly collected in the 3rd (−5 °C) and 4th (−20 °C) condensers, having high water content in the range of 35.33%–65.09%. The separation of acidic nature compounds such as acetic acid in the 3rd and 4th was evidenced by its low pH in the range of 4–5, while the pH of liquid collected in the 1st and 2nd condensers exhibited higher pH (6–7). The well-separated bio-oil derived from biomass pyrolysis facilitates its wide usage in various applications, proposing a unique approach toward carbon neutrality. In particular, achieving efficient separation of phenolic compounds in bio-oil is important, as these compounds can undergo further upgrading to generate hydrocarbons and diesel fuel.

Application of machine learning in optimizing thermochemical conversion processes with pre-treatment to get higher bio-oil yield from biomass waste

Application of machine learning in optimizing thermochemical conversion processes with pre-treatment to get higher bio-oil yield from biomass waste

Effect of Fe, Ni, and Co on the hydrothermal liquefaction of Chinese herb residue for bio-oil production

This study investigated the effects of reaction temperature (300–360 °C), reaction time (0–60 min), and the ratio of raw materials to solvent (1:5–1:15; g/mL) on the HydroThermal Liquefaction (HTL) of Chinese Herb Residues (CHR) for Bio-Oil (BO) production. Optimal HTL conditions for CHR were determined. To enhance both the yield and quality of BO, metal-modified catalysts including Fe/MCM-41, Co/MCM-41, and Ni/MCM-41 were prepared. These catalysts, after hydrogen reduction, loaded metal elements in their elemental state onto the carrier. Subsequently, CHR catalytic HTL experiments were conducted at 330 °C for 15 min with a ratio of 1:10 (g/mL). BO analysis was performed using EA, GC-MS, and FT-IR. Under the optimal HTL conditions (330 °C/15 min/1:10), the BO yield reached 24.57 wt.%, with a Higher Heating Value (HHV) of 25.96 MJ/kg. The major components of the BO included phenols, ketones, acids, and esters. In the catalytic HTL, Fe/MCM-41 (26.15 wt.%), Ni/MCM-41 (26.2 wt.%), and Co/MCM-41 (27.05 wt.%) catalysts each achieved higher BO yields. When using Ni/MCM-41 catalyst, the highest HHV of BO reached 32.01 MJ/kg, representing an 81% improvement over CHR HHV of 17.66 MJ/kg. Additionally, with Fe/MCM-41 catalyst, the lowest oxygen content in BO was 9.68%, and the selectivity for phenols and ketones was the highest, showing increases of 15.22% and 33.15%, respectively, reaching 44.13% and 24.5%. The results indicate that HTL can effectively convert high-moisture CHR into valuable products. Hydrogen-reduced metal-modified catalysts contribute significantly to increasing BO yield, promoting deoxygenation and hydrogenation reactions, and markedly improving HHV and the selectivity of chemical components, thereby effectively enhancing both the yield and quality of BO.

Study of biooil production from sewage sludge of a municipal wastewater treatment plant by using hydrothermal liquefaction

To overcome the problem of rapid depletion of natural energy reserves and consequent pollution caused by them, this work explored the possibility of utilizing sewage sludge biomass to produce biooil using hydrothermal liquefaction pathway. In this study, effect of different reaction parameters such as reaction temperature, residence time, and sludge-to-water ratio on solid biomass conversion and bioyield and its higher heating value were investigated. Although maximum conversion of (99.7%) and highest biooil yield (22.01 wt.%) was achieved at 330?C, however optimum temperature was chosen as 300?C which produced conversion efficiency and yield of biooil very close (98.07% and 21.5 wt.%, respectively) to what was obtained at 330?C as lower temperature is beneficial for overall economy of the process. Similarly, a residence time of 60 minutes and sludge-to-water ratio of 1:6 was screened to be producing optimized yield of biooil. The higher heating valu of different fractions biooil was much improved (30.18 MJ/kg of acetone phase and 38.04 MJ/kg of dichloromethane phase) as compared to that of raw feedstock (12.74 MJ/kg). Carbon balance performed on the products indicated that maximum amount of carbon went to biooil phase (53.4 wt.%). However, a significant portion of carbon was lost (33.9 wt.%) due to the limitation of experiments at lab scale which involves evaporation and drying to reach final products. The Fourier transform infrared spectroscopy spectral analysis of different biooil phases showed that it was mainly made up of alcohols, alkane, ketones, aldehydes and carboxylic acids.

Green hydroxyapatite-zeolite catalyst derived from steel waste as an effective catalyst for the hydrocarbon production via co-catalytic pyrolysis of sugarcane bagasse and high-density polyethylene

Hydroxyapatite-zeolite (HAP-ZE) catalyst prepared from steel waste was utilised in co-catalytic pyrolysis of sugarcane bagasse (SB) and high-density polyethylene (HDPE) for bio-oil production. The highest bio-oil yield (71.19 wt%) was obtained at HAP-ZE to SB/HDPE ratio of 1:6, and mass ratio of SB to HDPE of 40:60. HAP-ZE favoured the production of hydrocarbon and alcohol and inhibited the production of acid. The acid sites promoted the hydrogenation and deoxygenation via hydrocarbon pool while the basic sites promoted the deoxygenation reactions via decarboxylation and decarbonylation. HAP-ZE large pores facilitates access of bulky pyrolyzates to active sites, promoting deoxygenation and hydrocarbons formation.