Maximum Bio-oil Yield Research Articles

Fast pyrolysis of agricultural residues: Reaction mechanisms and effects of feedstock properties and microwave operating conditions on the yield and product composition

Fundamental understanding of the pyrolysis process plays an indispensable role in valorization of wastes and the development of novel sustainable technologies. This study introduces a novel approach by investigating the reaction mechanisms involve in Microwave-Assisted Fast Pyrolysis (MAFP) to unveil the thermal decomposition of agricultural residues: pecan nutshell (NS), sugarcane bagasse (SB), and orange seed (OS) biomasses. The holistic understanding of the pyrolysis process for these biomasses was analyzed based on the final chemical compositions and yields of bio-oil, biochar and biogas and correlated to the microwave processing conditions and feedstock’s chemical composition. The findings revealed that the bio-oil is enhanced at moderated microwave energy (<5 GJ/t) as result of endothermic reactions such as heterolytic fragmentation, Maccoll elimination, Friedel-Craft acylation, Piancatelli rearrangement and methoxylation. The maximum yield of bio-oil for protein-rich biomass was due to selective heating (Paal-Knorr pyrrole synthesis, Baeyer-Villiger oxidation, Maillard reaction, and ring conversion of γ-butyrolactone). The formation of biochar and biogas is attributed to the repolymerization of aromatic aldehydes, hydrocarbons, amines, and ethers, as well as dehydroxymethylation and dealkylation processes. This study provides a comprehensive understanding of the reaction mechanisms for several wastes using microwave pyrolysis, to establish the bases for effective valorization and agricultural waste management.

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%.

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.

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.

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.

Study on a new reed-coal coupled power generation system in Wuliangsuhai Lake wetland —Life cycle assessment and economic and technical analysis

As a major hydrophyte in wetlands, reeds purify water by reducing water eutrophication and have high value-added potential as biomass fuel for power generation. Based on pyrolysis experiments, reed has the maximum bio-oil yield of 57.11% at 550 °C. In this study, the optimal temperature conditions were used for the pyrolysis of reeds coupled with thermal power generation (BP-TPG). The BP-TPG process is relatively independent and avoids the deposition of alkali metals from biomass on the surface of the steam generator directly. The BP-TPG and biomass gasification coupled thermal power Generation (BG-TPG) were further investigated by process simulation and life cycle assessment. The GWP values of BP-TPG systems could be reduced by at least 4.8% than that of TPG. As the growth of reeds absorbed total nitrogen (TN) and total phosphorus (TP) from the wetland water, the eutrophication potential was reduced by 0.333 kg PO4/MWh less than that of the use of corn straw feedstocks. Economic and technical analysis showed that the BP-TPG-G system had the lowest cost of electricity generation at 386 ¥/MWh. Sensitivity analysis showed that the impact of coal prices on power generation costs cannot be ignored.

A comprehensive analysis on the synthesis of value-added chemicals via slow pyrolysis: Valorisation of rapeseed residue, whitewood, and seaweed (Laminaria digitata)

Pyrolysis has emerged as a crucial thermochemical conversion technology in the field of biomass processing. Maximising the valorisation of biomass is an essential area of investigation, as it plays a pivotal role in understanding the economic viability and practical application of these advanced technologies. The novelty of this research is to investigate how slow pyrolysis and process interdependencies influence the synthesis of value-added products (bio-oil and biogas formation alongside biochar) from distinctly different UK-based biomass feedstocks: rapeseed residue, whitewood, and seaweed (Laminaria digitata). This research also analysed the chemical composition of these products to provide a holistic understanding of the reaction mechanisms involved in their formation. The maximum yield of bio-oil from lignocellulose-rich whitewood was due to the higher selectivity of several endothermic reactions including conversions of 5-hydroxymethylfurfural into cyclic C5-ketones and alkoxyphenols into cresols and aliphatic hydrocarbons, minimizing the biochar formation. The improvement of bio-oil yield from protein-rich seaweed and lipid-rich rapeseed residue was enabled by the formation of N-heterocyclics (e.g., via the Maillard reaction, Dieckmann cyclization, and Buchwald–Hartwig amination) and aliphatic hydrocarbons (e.g., via deamination of fatty amides and nitriles and decarboxylation of fatty acids), respectively. Meanwhile, the dealkylation and demethoxylation of alkoxyphenols and alkylphenols were responsible for the increased content of hydrocarbons in biogas. The findings provide valuable insights into the maximum valorisation of different types of UK-based biomass resources in slow pyrolysis for the production of biochars and lighter bio-oils to make pyrolysis a key process in biorefineries.

Pyro-gasification of Rice Husk to Bio-fuel

Rice husk is a promising candidate of sustainable biomass-based renewable energy source with a gross caloric content of around 19.73 MJ/kg. As an efficient thermo-conversion process, pyro-gasification has the potential to convert biomass into oil and gas fuels. However, the bio-oil and gas yields are strongly dependent on the pyro-gasification operating parameters. This study employed response surface methodology (RSM) based on central composite design (CCD) experiment to determine the optimum conditions for pyro-gasification of rice-husk. Three selected most influencing operating parameters, namely feed mass (g), nitrogen flow (mL/min), and reactor temperature (°C) were optimized through 16 individual experimental runs for their possible synergistic effects. The results show excellent model fitting criteria (R2 &gt; 0.9 and R2-adj &gt; 0.85) for bio-oil and gas product responses that proves the suitability of RSM based on CCD experiment for rice-husk pyro-gasification study. The optimized optimum condition for rice-husk pyro-gasification process was at 897 g of feed mass, 1.97 mL/min of N2 gas flowrate, and 593 °C of reaction temperature. These conditions allow the achievement of estimated bio-oil and gas product yield of 47.78% and 11.41%, respectively. The composition analysis revealed that the main component of bio-oil was C15 (unsaturated), whereas the gas products were C3–C4 . This study suggests that rice-husk pyro-gasification is capable to achieve maximum yield of bio-oil and gas products with low char generation.

Production of bio-oil from lychee-based biomass through pyrolysis and maximization of bio-oil yield with statistical and machine learning techniques

This study's goal is to maximize the yield of pyrolysis oil utilizing lychee-based biomass for a quick pyrolysis process. Response surface methodology (RSM) and artificial neural network with generalized neural network (GNN) technique were used to optimize the maximum bio-oil yield while considering temperature, heating rate, retention time, and argon gas flow rate as independent variables and bio-oil production as the response. Typical neural networks have constraints such as a long training time, a large number of neurons, and a large number of hidden layers. A generalized neural network (GNN) has been constructed to address these limitations and build a non-linear controller for acquiring access to bio-oil production output. To anticipate bio-oil yield, a new prediction model is proposed that combines the benefits of an auto-adaptive management technique with the rapid reaction of a GNN. Three measures (MSE, RMSE, and R2) are explored in depth to assess the performance efficacy of the models. Based on the finding, 350 °C temperature, 125 min of retention time, 120 °C/min heating rate and 110 mL/min argon flow rate was used to produce the highest bio-oil production (38.43%). Based on techniques, both models used in the study produce equally acceptable outcomes for projecting bio-oil yield. The greatest R2 value for the bio-oil yield ranges from 0.94 to 0.99, and all outcomes are classified as "good" regarding RMSE (all RMSE values are close to one). When all indicators are combined, GNN provides superior accuracy in predicting bio-oil yield in this investigation, followed by ANN.

Response Surface Methodology for the Synthesis and Characterization of Bio-Oil Extracted from Biomass Waste and Upgradation Using the Rice Husk Ash Catalyst.

Rice husk ash (RHA), a low-cost biomaterial, was utilized to form bio-oil from pyrolysis in a batch-stirred reactor, followed by its upgradation using the RHA catalyst. In the present study, the effect of temperature (ranging from 400 to 480 °C) on bio-oil production produced from RHA was studied to obtain the maximum bio-oil yield. Response surface methodology (RSM) was applied to investigate the effect of operational parameters (temperature, heating rate, and particle size) on the bio-oil yield. The results showed that a maximum bio-oil output of 20.33% was obtained at 480 °C temperature, 80 °C/min heating rate, and 200 μm particle size. Temperature and heating rate positively impact the bio-oil yield, while particle size has little effect. The overall R2 value of 0.9614 for the proposed model proved in good agreement with the experimental data. The physical properties of raw bio-oil were determined, and 1030 kg/m3 density, 12 MJ/kg calorific value, 1.40 cSt viscosity, 3 pH, and 72 mg KOH/g acid value were obtained, respectively. To enhance the characteristics of the bio-oil, upgradation was performed using the RHA catalyst through the esterification process. The upgraded bio-oil stemmed from a density of 0.98 g/cm3, an acid value of 58 mg of KOH/g, a calorific value of 16 MJ/kg, and a viscosity 10.5 cSt, respectively. The physical properties, GC-MS and FTIR, showed an improvement in the bio-oil characterization. The findings of this study indicate that RHA can be used as an alternative source for bio-oil production to create a more sustainable and cleaner environment.

Comparison of non-catalytic and in-situ catalytic pyrolysis of Melia azedarach sawdust

This study focused on the in-situ catalytic pyrolysis of Melia azedarach sawdust by impregnating it with copper (Cu). Native and Cu impregnated Melia azedarach sawdust (MAS-N and MAS-C, respectively) were subjected to pyrolysis. MAS-N and MAS-C were characterized using proximate, ultimate and HHV analysis. Thermal degradation performance of MAS-N and MAS-C were examined by thermogravimetric analysis. Similar shapes of thermogravimetric curves indicated that Cu metal did not alter degradation pathway but lowered decomposition temperature and higher reaction rates were noticed for MAS-C due to catalytic effect of Cu. Optimization of operating process parameters was done by varying temperature, sweeping gas flow rate, particle size, packed bed height, pyrolysis time and heating rate for MAS-N. Maximum bio-oil yield for MAS-N was obtained at 550 ℃ temperature, 150 mL/min nitrogen flow rate, 8.4 cm bed height, 0.18–0.29 mm sized particles, 20 ℃/min heating rate and 60 min pyrolysis time. Further, effect of variation in temperature and catalyst to biomass ratio was studied for MAS-C and maximum bio-oil yield for MAS-C was obtained at lower temperature than that for MAS-N. Results were compared for catalytic and non-catalytic pyrolysis products via various characterization methods. Bio-oil properties were analysed by FTIR, GC-MS and 13C NMR. Proximate, ultimate, HHV, FTIR, XRD, SEM and BET surface area analysis were used to characterize properties of bio-char. Results suggested that Cu has catalytic effect on pyrolysis products. This article will be useful for promoting future research related to using heavy metal contaminated biomass as potential opportunities.

Microwave Assisted Pyrolysis of Moringa Seed and Karanja for Bio-Oil Production

Microwave-assisted pyrolysis is an alternative technique of conventional heating which undergo thermochemical process to convert biomass to bio oil, bio char and biogas. Microwave-assisted pyrolysis is more rapid and efficient to produce product compared to conventional heating. A modified household microwave oven with 800W was used to pyrolyze Moringa seed and Karanja to become bio oil and bio char. This experiment was repeated in different parameters such as time, temperature and power to obtain maximum bio oil yield. Bio oil yield of Moringa seed increased from 7.2 wt% at 300°C in 5 minutes to 10.6 wt% at 450°C in 13 minutes. Bio oil of both raw materials showed maximum yield when pyrolysis time is 13 minutes in 800W but after 13 minutes, the bio oil yield of Moringa decrease of 2.4% and bio oil yield of Karanja decrease of 4.7%. The calorific value of Moringa bio oil is 25.08MJ/kg whereas Karanja bio oil is 20.36 MJ/kg. Functional group of both bio oil mainly include alcohol, ketones, aldehydes and carboxylic acid. The pH value of Moringa bio oil and Karanja bio oil are 4.38 and 5.86 respectively.

Production optimization of refined bio-oil through plasma coupling catalysis and composite zeolite effect of Al-SBA-15/HZSM-5

Waste biomass was initially subjected to catalytic pyrolysis for aromatic bio-oil using HZSM-5 coupled with plasma discharge, and response surface methodology based on Box-Behnken design was employed to study the effects of process factors on bio-oil yield. Then, the mesoporous Al-SBA-15 was integrated at optimal conditions to investigate the effect of composite zeolites on bio-oil composition and catalyst stability. Results indicated that process factors on bio-oil yield and their interactions were significant. The maximum bio-oil yield of 41.80 % was obtained at the discharge current of 186 mA, catalytic height of 18 mm, and catalyst diameter of 2.5 mm. The selectivity of MAHs when using HZSM-5 alone reached 71.56 %, where the plasma discharge activation and the plasma sheath mass-transfer played an important role in synergy. When the ratio of Al-SBA-15 to HZSM-5 layers was 1:3, the highest MAHs selectivity of 79.45 % was acquired with a lower bio-oil yield of 35.33 %; herein, Al-SBA-15 provided suitable macromolecular cracking performance. 1H NMR clearly revealed the rich aliphatic sidechains characteristic of aromatic hydrocarbons from the perspective of hydrogen bonding structure. Used HZSM-5 contained thermal and catalytic cokes with higher decomposition temperatures (541-649℃ and 676-702℃) due to plasma discharge. Increased Al-SBA-15 ratio reduced the coke content from 1.19 % to 0.11 % on used HZSM-5, and thermal coke decreased more obviously from 0.78 % to 0.05 %; besides, the coke on used Al-SBA-15 also decreased from 6.66 % to 2.80 % and tended to be surface thermal coke (from 3.65 % to 2.80 %). In sum, the refined bio-oil produced at Al-SBA-15/HZSM-5 ratio of 1:3 was more suitable to be used as the fuel additive, and the composite zeolite had elevated stability.

Effect of transition metal oxide on microwave co-pyrolysis of sugarcane bagasse and Chlorella vulgaris for producing bio-oil

Bio-oil produced by biomass pyrolysis has been widely concerned because of its clean and sustainable advantages. In this work, the co-pyrolysis characteristics and product yield of sugarcane bagasse (BA) and Chlorella vulgaris (CV) under different CuO additions were studied using microwave oven. Then the components of bio-oil were identified by GC-MS. The results showed that co-pyrolysis optimized the pyrolysis characteristics and improved the yield and quality of bio-oil. B8C2 (BA/CV=8:2) group was the optimal mixing ratio with the maximum bio-oil yield and best pyrolysis characteristics. CuO promoted the bio-oil production of B8C2, and 50% CuO improved the pyrolysis characteristics most effectively. Besides, the co-pyrolysis of BA and CV played an obvious denitrification effect, promoted the formation of long-chain fatty acids, N-heterocycles, phenols and polycyclic aromatic hydrocarbons (PAHs), and increased the higher heating value (HHV) of bio-oil. CuO increased the contents of phenol and furans, and decreased acid value and sulfur content of bio-oil, thus making it more accessible for processing and utilisation at a later stage.

Conversion of Waste Cooking Oil into Bio-Fuel via Pyrolysis Using Activated Carbon as a Catalyst.

The utilization of activated carbon (AC) as a catalyst for a lab-scale pyrolysis process to convert waste cooking oil (WCO) into more valuable hydrocarbon fuels is described. The pyrolysis process was performed with WCO and AC in an oxygen-free batch reactor at room pressure. The effects of process temperature and activated carbon dosage (the AC to WCO ratio) on the yield and composition are discussed systematically. The direct pyrolysis experimental results showed that WCO pyrolyzed at 425 °C yielded 81.7 wt.% bio-oil. When AC was used as a catalyst, a temperature of 400 °C and 1:40 AC:WCO ratio were the optimum conditions for the maximum hydrocarbon bio-oil yield of 83.5 and diesel-like fuel of 45 wt.%, investigated by boiling point distribution. Compared to bio-diesel and diesel properties, bio-oil has a high calorific value (40.20 kJ/g) and a density of 899 kg/m3, which are within the bio-diesel standard range, thus demonstrating its potential use as a liquid bio-fuel after certain upgradation processes. The study revealed that the optimum AC dosage promoted the thermal cracking of WCO at a reduced process temperature with a higher yield and improved quality compared to noncatalytic bio-oil.

Reaction kinetics for hydrothermal liquefaction of Cu-impregnated water hyacinth to bio-oil with product characterization

Hydrothermal liquefaction is a promising technology for the conversion of biomass to bio-oil and gaseous fuels. In the present work, isothermal hydrothermal liquefaction experiments of Cu-impregnated water hyacinth were conducted at 280 °C and investigated the effect of reaction time (10 min to 45 min) on bio-oil, carbon hybrids, aqueous products, and gas yields. A short residence time of 15 min was found to be optimum to achieve a maximum total bio-oil yield of 34.82% and analyzed by GC-MS and NMR for identification of compounds. Solid residues were analyzed by FESEM, XPS, XRD, and BET for morphological study, Cu loading, and its transition in the hydrothermal environment. Based on experimental data, reaction kinetics was developed and compared for hydrothermal liquefaction of Cu-impregnated water hyacinth with raw water hyacinth to predict the influence of Cu metal on reaction rate constants during hydrothermal liquefaction. From the kinetic modeling, it was found that the presence of Cu promoted the biomass conversion to bio-oil with light oil to heavy oil ((k4) 0.24404 min−1) conversion being the dominating reaction path. In contrast to catalytic degradation, the light oil conversion to aqueous phase components with a rate constant of 0.26323 min−1 is the most prevailing step for non-catalytic hydrothermal liquefaction.

Catalytic (copper) hydrothermal liquefaction for lignin to produce high quality bio-oil and nano Cu carbon hybrids material

The in-situ hydrothermal liquefaction of direct Cu salt solution with lignin and Cu-impregnated lignin was performed with a motive to enhance the bio-oil yield along with the generation of nanometal carbon hybrids. The key operating parameter, temperature (200 °C to 320 °C) was varied, and the performance of both processes was evaluated based on the bio-oil yields. From the experiments, a maximum bio-oil yield of 28.74% and 24.87% was achieved for impregnated and direct process, respectively, at the optimum condition of 280 °C, 15 min, and the feed-to-solvent ratio of 1:9, which is almost double the non-catalytic bio-oil yields (10.16%) at the similar operating conditions. The XRD analysis confirmed the transition of Cu2+ to Cu+ and Cu. TEM inferred an average Cu particle size of 15.9 nm and 62.1 nm in hybrids material obtained from direct Cu effluent and Cu-impregnated lignin respectively.

Pyrolysis of pine needles: Parameter optimization using response surface methodology

Pine needles are forest residue-based biomass abundantly available in the Uttarakhand state of India. The presence of stranded pine needles in the forest land causes fires. At the same time, switching from fossil resources to renewable ones is the need of the hour. Among the available biomass conversion technologies, pyrolysis is a well-established and commercialized process. Therefore, the pyrolysis of pine needles to produce bio-oil with high yield and quality could be the best option for a sustainable future. Central composite design-based response surface methodology was employed to design the experiments. The study involved optimizing the process parameters such as temperature, residence time, and gas flow rate. The maximum bio-oil yield of 38.1 wt% was achieved at 500 °C, 30 min, and 50 mL·min−1 and the highest biochar yield of 60 wt% with a high heating value of 25.40 MJ/kg was obtained at 232 °C, 60 min, and 100 mL·min−1.

Pyrolytic conversion of agricultural residue using continuous auger reactor for resource recovery

In this research work, agricultural residue was pyrolytically converted in a continuous semi pilot auger reactor. Studies have been carried out with variation in operating conditions such as temperature, and its effect on product yield and quality has been analyzed comprehensively. It was found that with increase in temperature from 400 to 500 ℃, the oil yield increased; however, reduced on further increasing the temperature. The char yield decreased from 50 to 20 wt% and gas yield increased with rising temperature. For cotton stalk pyrolysis, maximum biochar yield of 51% was obtained at 400 ℃, whereas maximum bio-oil yield of 46.5% was obtained at 500 ℃. Maximum gas yield of 55% was obtained with mustard husk feedstock at 700 ℃ temperature. Water content of the cotton stalk bio-oil (35%) was found to be lower than mustard husk bio-oil (79%). The water content in bio-oil was found to enhance with increase in temperature. GC-MS analysis confirmed that different chemical value compounds are present in the bio-oils obtained from both cotton stalk and mustard husk. In addition, the chars obtained had a calorific value of 24.15 MJ/kg for cotton stalk and 24.57 MJ/kg for mustard husk. At 500 °C, biochar showed good thermal stability in TGA analysis and major weight loss occurred in the temperature range of 500–600 ℃. It was also observed that biochar contains high amount of micronutrients and can be used for improving crop productivity by partially replacing synthetic fertilizers.