Bio-oil Research Articles

Co-pyrolysis of pretreated cotton stalk and low-density polyethylene: Evolved products and pyrolysis mechanism analysis

The preparation of bio-oil from cotton stalks and agricultural residue films using co-pyrolysis technology can achieve resource recovery and energy conversion, which has important research value and significance. In this study, cotton stalks were subjected to different chemical pretreatments using NaOH, HCl, and H2O solutions to understand their structural changes and pyrolysis characteristics. In addition, the lower H/C ratio of cotton stalks resulted in higher oxygen content in the pyrolysis oil, which limited its efficient and clean utilization. Therefore, the characteristics and pyrolysis kinetics of the pyrolysis products of pretreated cotton stalks and LDPE (low-density polyethylene) were studied. The results showed that the ash content of alkali pretreatment cotton stalks decreased by 1.24 %, and the dense structure of cotton stalks significantly relaxed. NaOH pretreatment effectively removed hemicellulose sugars and cracked them. During the co-pyrolysis process, when the ratio of NaOH-CS/LDPE was 50/50, the synergistic effect was more pronounced, and the oil yield increased by 2 % compared to the theoretical value. The oxygen content of CO and CO2 in the pyrolysis gas was higher than the theoretical value, at 10.4 % and 14.1 % respectively. The synergistic effect of bio-oil on hydrocarbons was the most significant, reaching 18.9 %. More hydrogen and less oxygen migrated into the co-pyrolysis oil, resulting in an increase in hydrocarbons and a decrease in oxygen-containing compounds, and improving the quality of bio-oil. Results from electron paramagnetic resonance (EPR) indicated that adding LDPE might raise the quantity of stable free radicals. The evolution mechanism of functional groups of NaOH-CS and LDPE co-pyrolysis behavior was analyzed by Fourier in-situ infrared spectrometry (FTIR), and it was found that C–O–C, C=O, and O–H decreased due to dehydroxylation, decarboxylation, decarbonylation, and demethoxy reactions with the increase of temperature, indicating that there was a synergistic effect between NaOH-CS and LDPE co-pyrolysis. The pyrolysis kinetics of NaOH-CS, LDPE and their blends were determined by the model-free method. The introduction of LDPE can reduce the activation energy of NaOH -CS pyrolysis alone, and the 3D diffusion (D3) model is suitable for their blends.

Microwave-assisted co-pyrolysis of rice straw pellets and plastic packaging wastes for value-added products and energy recovery

The sustainable utilization of agricultural residues and waste plastics to mitigate environmental pollution, while generating renewable energy through pyrolysis has achieved significant attention through the years. In this study, microwave-assisted pyrolysis and co-pyrolysis of plastic packaging wastes (PPW) and rice straw pellets (RSP) of different mixture compositions (10 % PPW, 20 % PPW, and 30 % PPW) have been carried out to evaluate the synergistic effect of the two different feedstocks on product yields, composition, energy recovery, energy and exergy efficiency. With an intention to avoid pulverization of the feedstocks to fine particle sizes, a unique configuration resembling a chocolate is adopted to mix the biomass pellet with sheets of PPW, while using activated carbon as a susceptor. The calorific value of the co-pyrolysis oil was higher (30–35 MJ kg−1) than the pyrolysis oil obtained from RSP (22–28 MJ kg−1). The maximum oil yield from co-pyrolysis was 40 wt% for a feed-to-susceptor ratio of 2.5:1 w/w, 10 % PPW at 600 °C, and 800 W microwave power. Compared to the pyrolysis of RSP, co-pyrolysis resulted in significant deoxygenation in the oil fraction (50–60 %). The oil composition data revealed an increase in aliphatic hydrocarbons from 37 % to 42 % along with increased aromatics from 13 % to 19 % when PPW content was increased from 10 % to 30 % in the feedstock. High energy recovery (∼91 %) and feed conversion efficiency (∼99 %) were recorded for 20 % PPW at 800 W and 600 °C. The net energy balance for co-pyrolysis was positive (9–16 MJ kg−1) at different reaction conditions, which proves the energetic feasibility of the process. At 800 W and 600 °C, the total exergy efficiency was maximum (57.7 %) for 10 % PPW feedstock, and the exergy efficiencies were lower than the energy efficiency values.

Electrocatalytic Conversion of Phenol to Cyclohexane Using Pt and Ru-Based Catalysts

The production of renewable fuels has become necessary as fossil fuels continue to deplete.1 Pyrolysis of biomass to liquid fuels has emerged as a promising solution due to the possibility of conversion of high carbon content feedstocks into fuel. Pyrolysis oils, however, struggle from low yields and increased heteroatom content.2 In order to solve this problem a second upgrading step is needed to increase the fuel’s hydrogen content and remove heteroatoms. Conventional oil upgrading through thermochemical processes is an option using high temperatures (>300 °C) and high-pressure hydrogen (10-20MPa).3 Electrochemical upgrading of bio-oils represents a novel avenue for the conversion of bio-oils to usable fuels or commodity chemicals under mild condition which requires milder temperatures (30-80 °C) and generates the hydrogen in situ through the water splitting reaction.3 Though initial results on electrocatalytic upgrading have been promising, few studies report appreciable yields of fully deoxygenated products and the efficiency remains low at high current densities.3 This work focuses on the upgrading of phenol as a bio-oil model compound. ECH of phenol was investigated in a custom electrochemical cell (H-Cell), with a solvent trap for the collection and quantification of volatile organic products. Efficient ECH conversion of phenol to cyclohexane was demonstrated and the primary factors impacting the selective production of cyclohexane were studied. Multiple variables, including catalyst type, electrolyte composition and concentration, and cathodic potential were investigated to determine their influence on ECH reaction rate, selectivity, and efficiency. The results obtained show that lab-synthesized, bi-metallic PtRu-C catalyst results in the highest specific ECH rate of 23.52 mol h-1 g-1 metal in comparison to 19.92 mol h-1 g-1 metal, 15.84 mol h-1 g-1 metal and 4.64 mol h-1 g-1 metal, measured with a commercial PtRu-C and mono-metallic Pt-C and Ru-C catalysts, respectively. In addition, the lab synthesized PtRu-C catalyst achieved > 30% selectivity towards cyclohexane, which is among the highest reported in literature to date. Constant potential experiments showed that the cyclohexane was 4.6% higher at -0.46 V vs Ag/AgCl than -0.28 V vs Ag/AgCl indicating cyclohexane selectivity is weakly dependent on cathodic potential. To improve the mechanistic understanding of phenol ECH, operando Raman spectroscopy was explored, finding strong evidence for cyclohexanone reaction intermediates.References(1) Zhang, X.; Lei, H.; Chen, S.; Wu, J. Catalytic Co-Pyrolysis of Lignocellulosic Biomass with Polymers: A Critical Review. Green Chemistry. 2016. https://doi.org/10.1039/c6gc00911e.(2) Zhang, B.; Zhong, Z.; Min, M.; Ding, K.; Xie, Q.; Ruan, R. Catalytic Fast Co-Pyrolysis of Biomass and Food Waste to Produce Aromatics: Analytical Py-GC/MS Study. Bioresour. Technol. 2015, 189. https://doi.org/10.1016/j.biortech.2015.03.092.(3) Chen, G.; Liang, L.; Li, N.; Lu, X.; Yan, B.; Cheng, Z. Upgrading of Bio-Oil Model Compounds and Bio-Crude into Biofuel by Electrocatalysis: A Review. ChemSusChem. 2021. https://doi.org/10.1002/cssc.202002063. Figure 1

Electrocatalytic Upgrading of Biomass-Derived Compounds for Biofuel Production

Biomass fast pyrolysis liquid (also known as bio-oil) is considered to be one of the most promising renewable carbon feedstocks. However, fresh pyrolyzed bio-oil is acidic and corrosive and contains large amounts of carbonyl and phenolic compounds produced by polymerization under acidic conditions. This work primarily utilizes an electrochemical conversion strategy using only earth-abundant metal catalysts to achieve the carbonyl hydrogenation process. The results show that upgrading this process produces biofuels with greater stability and higher specific energy. In addition to analyzing the chemical implications of this conversion strategy, this work will also discuss why electrocatalytic conversion is a promising technology path for biofuels and fine chemicals. Reference Huang, S., Lam, C. H.* et al. (2022). "The Structural Phase Effect of MoS2 in Controlling the Reaction Selectivity between Electrocatalytic Hydrogenation and Dimerization of Furfural." ACS Catalysis 12(18): 11340-11354.Huang, S., Lam, C. H.* et al. (2022). "MoS2-Catalyzed Selective Electrocatalytic Hydrogenation of Aromatic Aldehydes in an Aqueous Environment." Green Chemistry.Tu, Q., Lam, C. H.* et al. (2021). "Electrocatalysis for Chemical and Fuel Production: Investigating Climate Change Mitigation Potential and Economic Feasibility." Environmental Science & Technology 55(5): 3240-3249.Garedew, M., Lam, C. H.* et al. (2020). "Greener Routes to Biomass Waste Valorization: Lignin Transformation Through Electrocatalysis for Renewable Chemicals and Fuels Production." ChemSusChem 13(17): 4214-4237. Lam, C. H., et al. (2017). "Towards sustainable hydrocarbon fuels with biomass fast pyrolysis oil and electrocatalytic upgrading." Sustainable Energy & Fuels 1(2): 258-266. Figure 1

Chemical characterization of bitumen-derived pyrolysis oil

The objective of this study is to characterize the elemental and functional group analysis of oils obtained from the pyrolysis of oil sand bitumen with the aim of determining oil quality. For this purpose, the present study extracted bitumen from oil sand using toluene, thermally cracked the bitumen using a fixed bed reactor, chromatographically separated the derived oil into saturate and aromatic fractions, and employed Energy dispersive x-ray fluorescence and Fourier transform-infrared spectroscopy to characterize them. The results of the elemental analysis indicated that potassium had the highest mean concentration of about 531 mg/L and 552 mg/L in the saturate and aromatic fractions respectively. The mean elemental concentrations of the aromatic fraction were relatively higher than the saturate fraction. The functional group analysis showed the predominant presence of C-H (CH3) and C-H (CH2) groups, indicating the presence of aliphatic compounds in the pyrolytic oils, in addition to the presence of sulfur reflected by the sulphoxide index. The findings of the study provide valuable information on the feedstock potential of the pyrolysis oil in the petrochemical industry. This study provides baseline information required for exploitation of the heavy oil resource which is yet to be commercially mined in Nigeria.

Valorizing polymeric wastes and biomass through optimized co-pyrolysis for upgraded pyrolysis oil: A study on TG-FTIR and fixed bed reactor

The co-pyrolysis of biomass and polymeric wastes offers a promising approach for waste reduction and valuable product recovery while decreasing fossil fuel dependence. This study aimed to investigate the synergistic effects of blending waste tire (WT) or polystyrene (PS) with sawdust (SD) at varying effective hydrogen/carbon ratio (H/Ceff) on liquid product distribution. Thermal degradation behavior was analyzed using TGA-FTIR, followed by fixed-bed reactor pyrolysis experiments at different temperatures. The devolatilization of SD primarily occurred between 185 and 390°C, while WT and PS decomposed between 250 and 500°C and 350–460°C, respectively. Results showed that SD addition to WT accelerated degradation at lower temperatures. Optimal H/Ceff ratios were 0.42 for WT/SD and 0.64 for PS/SD blends at 500°C, maximizing valued hydrocarbons, reducing pollutants, and yielding the highest liquid fraction. TGA-FTIR analysis revealed the presence of various functional groups, including C-H, CC, CO2, and O-H. The pyrolytic oil showed improved stability with significantly fewer undesired compounds. This research provides theoretical and practical insights into the control and application potential as well as the limitations of high-value energy products derived from the co-pyrolysis of SD, WT, and PS.

Low temperature pyrolysis of waste cooking oil using marble waste for bio-jet fuel production

Limestone powder, a by-product of top-down marble processing, exhibited high thermal stability and functionality as catalysts for the low-temperature pyrolysis of waste cooking oil (WCO) into biofuel. The marble waste (MW) contains calcite, dolomite, and quartz composites (CaCO3/MgCO3/SiO2) as non-uniform microcrystallites. Pyrolysis at 380 °C in 1 h increased the hydrocarbon composition of biofuel and reduced carboxylic acid. The biofuel composition contains 80 % hydrocarbon within the jet fuel C8-16 ranges. MW reduced the carboxylic acid concentration from 49 % in catalyst-free pyrolysis to less than 4 %. The optimum condition was obtained at 3 % MW, yielding 43.55 % linear hydrocarbon, 11.1 % cyclic hydrocarbon, and 1.02 % aromatic compounds that satisfied the bio-jet fuel classification. The incorporation of varying percentages of marble waste demonstrates a significant enhancement in the cyclic compounds, elevating the yield from ∼3 % in catalyst-free pyrolysis to an impressive ∼35 %. The hydrocarbon yield is higher when using 3%MW > 1%MW > 6%MW > 9%MW. Dolomite and calcite mixture in MW catalyzed triglyceride conversion to hydrocarbon by adsorbing carbonate in triglycerides to drive C–O bond dissociation. These studies provide a roadmap for the utilization of abundant resources locally available in Indonesia to sustain local energy demand.

Synthesis of benzoic acid from catalytic co-pyrolysis of waste wind turbine blades and biomass and their kinetic analysis

This work aims to study the catalytic co-pyrolysis of waste wind turbine blades (WTB: consists of fiberglass/unsaturated polyester resin) and woody biomass (WB) over ZSM-5 and Y-type zeolite catalysts for the production of benzoic acid. The experiments were performed on an equal combination of WTB and WB (WTB/WB) and a fixed amount of catalyst (50 wt%) using a thermogravimetric (TG) analyser at 10, 20 and 30 °C/min. The evolved products from the catalytic co-pyrolysis process were recognized using TG-FTIR and GC/MS. The kinetic and thermodynamic characteristics of catalytic co-pyrolysis was studied using various linear and nonlinear approaches. Also, the decomposition curves were predicted mathematically using an artificial neural network algorithm. The results revealed that the mixture was decomposed in the presence of both catalysts in the form of dual decomposition peaks at 361–374 °C and 428–443 °C, respectively. Based on TG-FTIR results, the CO stretching and carbon dioxide clusters were their main functional groups. While the GC-MS analysis revealed that the released vapours were completely free of toxic styrene (the main compound of resin) and the catalytic co-pyrolysis treatment succeeded in converting it into highly abundant benzoic acid, especially at 10 °C/ min, with an estimated 71.4 % (ZSM-5) and 64 % (Y-type). Whereas the activation energy was estimated at 262–295 kJ/mol (ZSM-5) and 319–357 kJ/mol (Y-type) with almost similar reaction complexity when compared to the case of absence of catalysts. Finally, the developed ANN algorithm showed high efficiency in predicting TG decomposition zones for both WTB/WB mixtures over zeolite catalysts with R2 more than 0.99. These results demonstrate that WB and zeolite catalysts can be used for upgrading the pyrolysis oil of WTB and eliminate its toxic styrene and convert it into benzoic acid and other aromatic hydrocarbons compounds (such as benzene, alanine, and 2-Propanamine).

Co-pyrolysis of wheat straw with polyester-based polyurethane for nitrogenous compounds: Pyrolysis kinetic properties and synergistic effects

To re-utilize agricultural waste straw and waste plastic, the co-pyrolysis process of wheat straw (WS) and high-nitrogen polymer polyester-based polyurethane (PU) and the synergistic effects were studied. The results showed that PU facilitated pyrolysis to occur at lower temperatures. The effective apparent activation energies (Eα) of different samples were calculated at different conversion rates with three methods (Kissinger, KAS and Starink). It was found that PU decreased the Eα values and enthalpy change of WS and increased the reactivity. Both ΔG and ΔS results indicate that a heating rate of 5 ℃/min is more favorable for co-pyrolysis. PU greatly promoted the production of pyrolysis oil. Co-pyrolysis oil doped with 75 % PU gave the highest yield of 77 wt%. Co-pyrolysis effectively suppressed the production of acids, aldehydes, and phenols in pyrolysis oils. It increased the levels of alcohols and ketones, improving the pyrolysis oil's stability and calorific value. α, β-unsaturated aldehydes produced by WS during pyrolysis reacted with hydrazine derivatives produced by PU pyrolysis to produce pyrazole compounds after dehydration. In the co-pyrolysis of 50 % doped PU, the reaction of methyl and methylene produced by WS with amines (-NH2) produced by the pyrolysis of PU promotes the production of trimethylamine. The yield of amines in the nitrogenous compounds reached a maximum at this time. PU increased the yield of nitrogenous compounds and their variety. It favored the output of high-value chemicals. FT-IR analyses of pyrolytic charcoal showed that the addition of PU promoted the cleavage of WS and the dehydration and decarboxylation reactions of C-O and C-O-C. Finally, synergistic effects and nitrogen conversion mechanisms in the co-pyrolysis process are proposed. This work provided a theoretical basis for the resource utilization of WS waste and PU waste.

Co-pyrolysis of refinery oil sludge with biomass and spent fluid catalytic cracking catalyst for resource recovery.

Catalytic co-pyrolysis of two different refinery oily sludge (ROS) samples was conducted to facilitate resource recovery. Non-catalytic pyrolysis in temperatures ranging from 500 to 600°C was performed to determine high oil yields. Higher temperatures enhanced the oil yields up to ~ 24 wt%, while char formation remained unchanged (~ 45%) for S1. Conversely, S2 exhibited a notably lower oil yield (~ 4 wt%) than S1. Pyrolysis oil of S1 consisted of phenolics (~ 50% at 600°C) whereas hydrocarbons were predominant in S2 oil (~ 80% at 600°C). Catalytic pyrolysis of S1 did not exhibit a substantial impact on oil yields but the oil composition varied significantly. High hydrocarbons, phenolics, and aromatics were obtained with molecular sieve (MS), metal slag, and ZSM-5, respectively. Catalytic co-pyrolysis of S2 with sawdust (SD) in the presence of MS enhanced the oil yield, and the resulting oil consisted of high hydrocarbons (~ 54%) and aromatics (~ 44%).

Performance and emission analysis of cassava peel waste pyrolysis oil-hydrogen-diesel blends in a compression ignition engine

As the world moves away from fossil fuels and embraces sustainable energy sources, the need for sustainable fuels for transportation becomes paramount. This study investigates the effects of pyrolysis oil derived from cassava peel waste (CPO), hydrogen (H), and diesel (D) blends as a partial substitute for low-displacement compression ignition engines. We tested three blends – CPO25, CPO25H5, and CPO25H10 – against neat diesel operation at engine speeds of 3400 rpm, 3600 rpm, and 3800 rpm and torques of 4 Nm, 6 Nm, and 8 Nm. Our findings reveal that while energy efficiency decreased with CPO25 compared to D100 operation, adding H2 increased energy efficiency. The highest increase was 7.8 % for CPO25H5 and 16 % for CPO25H10 compared to CPO25. Exergy efficiency also decreased with CPO25 compared to D100, but adding H2 compensated for this reduction. The highest increase was 8.0 % for CPO25H5 and 17 % for CPO25H10 compared to D100. CPO25H10 showed an increase of 8.1 % in combustion pressure and 9.9 % in heat release rate compared to CPO25. Emissions analysis also revealed that CO emissions were considerably lower with CPO and H2 than with D100, with the highest decrease of 11 % with CPO25H10. CO2 and hydrocarbon emissions followed the same trend as CO. Although NOx emissions slightly increased, the benefits of using pyrolysis oil-H2-diesel blends as a partial substitution fuel for low-displacement compression ignition engines are evident.

Waste Plastic Pyrolysis Industry: Current Status and Prospects

Pyrolysis is a technology that can produce pyrolysis oil by decomposing waste plastic, and has the advantage of being able to process contaminated waste plastic that is impossible to process with other technologies. In Korea, where the amount of waste plastic is increasing and natural resources such as fossil fuels are lacking, pyrolysis technology is attracting attention under the keyword ‘urban oil field’. The Ministry of Environment of the Republic of Korea announced a ‘plan to revitalize waste plastic pyrolysis’ to increase the proportion of waste plastic pyrolysis treatment from 0.1% in 2021 to 10% in 2030. The products of pyrolysis are both fuel and plastic raw materials, but the processing consumes significant energy. Therefore, as criticism continues that the marketability and economic feasibility of pyrolysis technology is poor, questions are being raised about its environmental friendliness. Against this background, this study investigated international trends in pyrolysis technology and performed a detailed comparative analysis with other technologies from an environmental perspective. According to the results of this study, currently environmentally advanced countries are very negative about using pyrolysis oil as fuel, and the following policy directions are suggested. 1) In order to comply with the mandatory use ratio of plastic recycled raw materials and at the same time achieve eco-friendliness, it is recommended to use pyrolysis technology as a plastic recycled raw material production technology rather than fuel conversion. 2) Since pyrolysis emits more greenhouse gases than physical recycling, pyrolysis technology is used as a complementary method to physical recycling to process waste plastics that are difficult to physically recycle. 3) Since physical recycling is very important in the resource circulation of waste plastic, the development of separation and sorting technology is promoted nationally.

Enhancing oxidative desulfurization using sludge-derived ferrate (VI) for dibenzothiophene: An optimization study

Sulfur emissions pose a substantial threat to human health and the environment. To address this, stringent regulations limit sulfur content in fuels, and innovative desulfurization technologies are under active investigation. Oxidative desulfurization (ODS) employs oxidants to convert sulfur compounds into more readily recoverable sulfones. This study explores high-shear mixing in ODS, known as mixing-assisted oxidative desulfurization (MAOD), focusing on dibenzothiophene (DBT) oxidation in model fuels and pyrolysis oil. Fe(VI) derived from drinking water treatment sludge via wet oxidation is utilized in the MAOD process. The research evaluates the impact of ferrate concentration (400–600 ppm), phase transfer agent (PTA) concentration (100–300 mg per 50 mL of fuel), agitation speed (4,400 to 10,800 rpm), and temperature (40–60 °C) on % DBT conversion. Experimental sulfur conversions range from 63.4 % to 99.6 %. Through response surface methodology, optimal parameters of 537 ppm Fe(VI), 114 mg PTA per 50 mL of model fuel, 8,157 rpm agitation speed, and 41.7 °C are determined. These parameters are applied to pyrolysis oil, achieving a desulfurization efficiency of 53.2 %. Notably, increasing Fe(VI) concentration, agitation speed, and temperature significantly enhances sulfur reduction. The study underscores the potential of using potassium ferrate derived from drinking water treatment sludge in MAOD for effective desulfurization and provides insights into the impact of operating conditions on desulfurization efficiency. Ultimately, the research contributes to advancing environmentally friendly and cost-effective desulfurization technologies.

Temperature effects on chemical reactions and product yields in the Co-pyrolysis of wood sawdust and waste tires: An experimental investigation

This study investigates the effects of varying temperatures on the co-pyrolysis of wood sawdust (WS) and waste tires (WT) within a stainless steel fixed-bed reactor under a nitrogen atmosphere. The experiments were conducted at three different temperatures: 400 °C, 500 °C, and 600 °C, focusing on the thermal behavior and resultant product yields. At 600 °C, WS produced the highest oil yield (63.6 wt%), suggesting a tendency to generate more aqueous and volatile components. Conversely, WT alone showed an optimal oil yield of 46.4 wt% at 500 °C, while the WS-WT blend achieved 55.6 wt%. Gas chromatography-mass spectrometry (GC-MS) analyses of the pyrolytic oils indicated that WS-heavy mixtures were rich in aliphatic compounds, whereas WT-dominant samples had increased aromatic and phenolic contents, demonstrating the potential for creating valuable chemicals from waste. Additionally, gas analysis highlighted significant variations in syngas composition, with increased methane and decreased CO2 levels at higher temperatures, emphasizing the role of the water-gas shift reaction. These findings underscore the critical importance of temperature control in optimizing the efficiency and quality of products from co-pyrolysis, presenting a viable method for enhancing the value derived from waste materials.

Properties and combustion characteristics of bioslurry fuels from agricultural waste pyrolysis

ABSTRACT The current research investigates the combustion characteristics of bioslurry fuel derived from the products of agricultural waste pyrolysis. The bioslurry fuel was prepared by mixing biochar and pyrolysis oil. The combustion characteristics of a suspended single droplet of the bioslurry were analysed. The results indicate that an increase in pyrolysis temperature (400–600°C) lead to higher concentrations of fixed carbon (56–60%), increased ash content (16–18%), and higher calorific values (25–32 MJkg−1). As the pyrolysis temperature rises, the biochar surface becomes more porous, lower volatile matter content and particle size. As biochar content increases, the bioslurry’s density, viscosity, and caloric value increase but stability index decreases. Higher biochar content in the bioslurry increases the ignition delay and burnout time while reducing the burning rate. The bioslurry fuel contained 30% biochar achieved a calorific value of 28 MJkg−1 and a viscosity of 600 cP, comparative to conventional fossil fuels. Highlights Up to 30% BC can be added to pyrolysis oil to produce SF. Pyrolysis temperature increased FC, ash, and calorific value of biochar. Biochar surface appears more porous with increasing pyrolysis temperature. Biochar content affects bioslurry combustion characteristics.

Combustion characteristics of crude tyre blends fuel in compression ignition engine

With the rise of automobile vehicles, the number of scrap tyres has been increasing rapidly. Proper management of waste tyre is challenging work for any country. Tyre oil possesses a greater potential of using as a substitute for conventional diesel. The investigation was made on the effects of blends of waste tyre fuel on combustion characteristics such as cylinder pressure (CP), net heat release rate (NHR), cumulative heat release (CHR), ignition delay (IGD), exhaust gas temperature (EGT), and % heat equivalent to brake power (HBP). It was found that crude tyre fuel has a low cetane index which affects the combustion characteristics. The two sample of test fuel were prepared by adding 5% crude tyre fuel to 95% diesel fuel (5BTF) and 10% crude tyre fuel to 90% diesel fuel (10BTF) by volume and their performance and emission characteristics were studied in a single cylinder four stroke diesel engine. For 10BTF, peak CP was reduced by 6.69%, IGD increased by 10.85%, NHR increased by 19.33% and there was a small difference in EGT with diesel. The opacity value of the blends of tyre fuel was found within the emission standard of Nepal. It is concluded that a blend of crude tyre pyrolysis oil up to 5% by volume with diesel shows similar combustion characteristics as that of diesel.

Influence of Carbonated Pyrolysis Oil Recycled from Scrap Tires on Metallurgical Efficiency of Coal Flotation

This research assesses the effect of carbonated pyrolysis oil (CPO) derived from scrap car tires on the metallurgical efficiency of coal flotation as a flotation additive. Using a statistical experimental design, the influence of various operational variables, including solid percent of feed pulp and dosages of reagents, i.e., CPO as an additive, diesel oil as a collector, and pine oil as a frother, on the ash content and yield of the final concentrate were investigated. Experimental data vary significantly based on operational conditions, ranging from 6.6% ash content with a 15% yield to 19.1% ash content with a 76.8% yield. The composition of the pyrolysis oil was identified by using Fourier transform infrared spectroscopy (FTIR). The analysis of variance (ANOVA) of experimental results demonstrated that almost all variables had a substantial effect on the flotation responses, positive or negative, depending on the variable or variable interaction. It was discovered that the usage of CPO intensified the total yield and ash content of concentrate in a nonlinear fashion in a range of 15% and 4%, respectively. The results revealed a non-selective interaction effect between CPO and pine oil, as well as competitive adsorption between diesel oil and CPO, which contributed to the curved behavior of flotation measurements. The detrimental effect of CPO on the flotation response of the studied coal sample was also related to the interaction of the hydrophilic groups in the CPO structure and the oxide groups of ash material in coal particles. This work shows the potential of carbonated pyrolysis oil to enhance coal flotation performance and sheds light on the underlying mechanisms.

Investigation of pyrolysis productions (pyrolysis oil, pyrolysis gas and carbon nanotubes) distribution in co-pyrolysis of torrefied oiltea camellia shells and polypropylene

The co-pyrolysis of torrefied oiltea camellia shells (OCS) and reused polypropylene (PP) was investigated for pyrolysis oil, pyrolysis gas and carbon nanotubes (CNTs) distribution characters in a two-stage pyrolysis system. Compared with raw OCS/PP, the quality of pyrolysis oil from torrefied OCS and PP was upgraded while yield decreased gradually. In particular, torrefaction pretreatment was beneficial to the formation of aromatic hydrocarbons and the higher selectivity of phenols in pyrolysis oil. And serious N2 torrefaction (260 N) and slight CO2 torrefaction (200C) is more conducive to the synthesis of C6–C11 (gasoline component). In addition, torrefaction could contribute to lower volatiles, which resulted in a lower yield of CNTs. For comparison, higher graphitized CNTs was prepared from the co-pyrolysis of torrefied OCS and PP. Appropriate torrefaction temperature and atmosphere have a potential for high value conversion of pyrolysis oil, pyrolysis gas and CNTs from co-pyrolysis of biomass and plastics.

An experimental and density functional theory investigation of the influence of HZSM-5 on pyrolysis oils produced from vanillin, a model lignin compound

Lignin, as a renewable energy source, has attracted much attention due to its high valorization potential. Due to the complex composition of lignin, vanillin, an important intermediate of lignin, was chosen as a model compound in this study. The study examined the influence of the HZSM-5 molecular sieve on the quality of pyrolysis oils during the catalytic pyrolysis of vanillin at 600 °C using a horizontal tube furnace and Py-GC/MS analysis. The results revealed that the HZSM-5 catalyst significantly increased the yields of toluene, guaiacol, and 4-hydroxyisophthalaldehyde by 2.49 %, 19.26 %, and 1.8 %, respectively, whereas reducing the contents of phenol and 3,4-dimethoxyphenol by 6.01 % and 3.79 %, respectively. These findings indicate that the HZSM-5 molecular sieve effectively improves the quality of pyrolysis oils during the catalytic pyrolysis of vanillin. The evolution of the main functional groups in the pyrolysis of vanillin was analyzed using an in situ diffuse reflectance infrared Fourier transform spectroscopy. The addition of HZSM-5 promoted the cleavage of oxygen-containing functional groups and the generation of aromatic hydrocarbons during the pyrolysis of vanillin. Furthermore, the pyrolysis reaction pathways of vanillin were simulated under the B3LYP/6-311 g (d, p) basis set using the density functional theory. The acidic sites of HZSM-5 interacted with vanillin via the hydrogen bonds that affected the energy barriers of the pyrolysis reaction pathways of vanillin. HZSM-5 inhibited the generation of phenol and 3,4-dimethoxyphenol by increasing the energy barriers by 32.95 and 31.03 kJ/mol, respectively; however, HZSM-5 promoted toluene production by decreasing the energy barrier by 37.38 kJ/mol. The effects of HZSM-5 on the products in the simulation results were consistent with the experimental results.

Catalytic Cracking of Crude Waste Plastic Pyrolysis Oil for Enhanced Light Olefin Production in a Pilot-Scale Circulating Fluidized Bed Reactor

Catalytic Cracking of Crude Waste Plastic Pyrolysis Oil for Enhanced Light Olefin Production in a Pilot-Scale Circulating Fluidized Bed Reactor