Fixed-bed Pyrolysis Reactor Research Articles

Evaluation of the properties of bio-asphalt derived from waste cooking oil and low-density polyethylene through the pyrolysis process

The aim of this study is to prepare a bio-asphalt for flexible pavement construction using a fixed-bed pyrolysis reactor. This method involves incorporating waste cooking oil (WCO) and low-density polyethylene (LDPE) as feedstock materials. Through this study, an attempt has been made to make use of waste materials and promote the use of environmentally friendly binders in sustainable road construction. The pyrolysis experiment was conducted at different temperatures, varying from 250 °C to 500 °C for different blends of waste cooking oil (WCO) and low-density polyethylene (LDPE), i.e., 1:0, 3:1, 1:1, 1:3, and 0:1, respectively. At a temperature of 350 °C, the pyrolysis process is more effective for converting various blends of waste cooking oil (WCO) and low-density polyethylene (LDPE) into bio-asphalt. The maximum bio-asphalt yield of 82 wt% was reported for the 1:3 blend at a temperature of 350 °C. The elemental analysis of an equal mass of waste cooking oil (WCO) and low-density polyethylene (LDPE) reported a carbon content of 83.93 wt%, a hydrogen content of 13.29 wt%, and a lower oxygen content of 2.55 wt%. The Gas Chromatography Mass Spectrography (GC-MS) analysis indicated the presence of chemical compounds such as pentadecane, heptadecane, dodecane, cyclopentylpropyl, and hexacosene in the 1:1 blend. The thermogravimetric and derivative thermogravimetric analyses indicate that the 1:1 blend and 1:3 blend can withstand temperatures around 473 °C and 475 °C, respectively. The Fourier transform infrared spectroscopy (FT-IR) analysis showed the presence of alkane, alkene, ester, and other aromatic compounds. Based on this present study, it has been noted that the chemical composition of a 1:1 blend of waste cooking oil (WCO) and low-density polyethylene (LDPE)-based bio-asphalt contains similar chemical compositions as asphalt binder, and it can be used as a modifier for conventional asphalt binder.

Potato peel carbon dots produced via fixed bed pyrolysis reactor decorated 1-D TiO2 nanorods for rapid removal of methylene blue, Cr (VI), Escherichia coli, and Aspergillus niger

In this work, new type carbon quantum dots produced from waste of biomass were used as a dopant molecule in order to investigated photocatalytic properties of TiO2 nanorods structures. Low-cost and eco-friendly carbon quantum dots (CQDs) were obtained via slow pyrolysis of potato peels (PP) as a biomass waste without any chemicals by fixed bed pyrolysis. Potato peel quantum dots (P-CQDs) decorated TiO2 nanorods (P-CQDs/TNRs) were synthesized were by utilizing their high specific surface area, good dispersion, abundant surface functional groups. (P-CQDs) were imposed on the surface of the one-dimensional TiO2 nanorods fabricated via chemical impregnation method for P-CQDs/TiO2 nanorods (P-CQDs/TNRs) that TiO2 nanorods have been fabricated by hydrothermal route. Characteristic properties of as-prepared P-CQDs/TNRs photocatalysts were characterized employing TGA, XRD, XPS, FE-SEM/EDS, HRTEM, FTIR, fluorescence and UV–vis spectroscopy, resp. The photocatalytic activity of as-prepared P-CQDs/TNRs were investigated for methylene blue, hexavalent chromium, Escherichia coli and Aspergillus niger under UV-A. The obtained results suggest that the photocatalytic activity of P-CQDs/TNRs composites was slightly enhanced as compared to that of TNRs. The scenario behind the superior photocatalytic activity of P-CQDs/TNRs may be having a synergetic effect between P-CQDs molecules and the surface of TNRs, and also the design of the charge-transfer channel of TNRs. Moreover, the carbon derived from a natural green source possesses the various functional groups such as CC, C-OH, C-O-C, CO, and when these functional groups deposited to the surface of the TiO2 nanorods, newly formed nanocomposites can improve the visible light-driven photocatalytic activity.

Upcycling of pine and sodium silicate composites through pyrolysis: Effects of pyrolysis temperature and sodium silicate content

In 3D-printing, sodium silicate (SS) can be used as an inorganic binder for wood-based composites due to its better rheological properties, high strength, and affordability. Investigating the recyclability of 3D-printed composites is necessary to understand the reusability of demolished additively manufactured construction waste. In this work, the bio-oil through pyrolysis was produced using pine and SS composites and further characterized to observe the effects of the pyrolysis temperatures and the proportion of SS in composites. Pine and SS composites with 0, 33.33, 50, and 66.67 % of the SS on a mass basis were prepared and cured to mimic the 3D-printed composites. Then, pyrolysis of cured composites was performed in a bench-scale fixed bed pyrolysis reactor at four temperatures (450–600 °C). From the pyrolysis of composites with 66 % SS at 600 ℃, a maximum condensed liquid yield of 68 % (wt.%, dry basis) was obtained. Further, it was observed that the selectivity towards hydrocarbons and alkyl phenols increased by increasing the proportion of SS in the composite, but methoxy phenols decreased, which enhanced bio-fuel production. A maximum hydroxyl concentration of 6.54 mmol g−1 was observed for the bio-oil from pyrolysis of SS-based composite at 600 ℃. This study shows the feasibility of upcycling the 3D-printed wood composites through pyrolysis to generate bio-oil that can be used for bio-based resin synthesis and bio-fuel applications.

Evaluating the blending potential of two different biomass via co-pyrolysis as sustainable pathway using RSM optimization for bioenergy and bio char production

The present study addresses the co pyrolysis of Lantana Camara (LC) and Spent Coffee Grounds (SCG) to produce renewable biofuels. The aim is to optimize the process by determining the optimal blending ratio, temperature, and residence time to obtain the highest bio-oil yield. The experiments were performed using a fixed-bed pyrolysis reactor, and the parameters were optimized using response surface methodology. The physicochemical properties of the products were analyzed using GC MS, XRD, FTIR, and TGA analysis. The results of the study show that the highest bio-oil yield was obtained at a blending ratio of 5(LC):5(SCG), a temperature of 500 °C, and a residence time of 6 min. The bio-oil yield increased from 23.3 wt.% at 400 °C to a maximum of 40.2 wt.% at 500 °C. Kinetic analysis was done using TGA data by plotting Coats Redfern plot. Activation energy for LC and SCG were found to be 31258.442 and 56766.714 J/mol, respectively, and Arrhenius parameters for LC and SCG were 113.66 and 8783.017, respectively. The bio char produced has potential applications in water treatment. Overall, the study identified optimal conditions for maximizing bio-oil yield, demonstrating a significant increase compared to traditional methods.

Biomass pyrolysis oil/diesel blends for a small agricultural engine

The present study reports on an investigation of teak sawdust pyrolysis oil blended with commercial diesel in a small four-stroke compression ignited engine. The engine performance and emissions were evaluated. The teak sawdust pyrolysis oil was obtained from a single-stage fixed bed pyrolysis reactor at 600 °C. Its physicochemical properties were characterized and found to be acceptable for the engine. Teak sawdust pyrolysis oil blends with diesel at the ratios of 10%, 25%, and 50% by mass were utilized. The small engine was tested at constant speeds from 800 to 2600 r/min. 25% teak sawdust pyrolysis oil blend at 2000 r/min was found to have better brake thermal efficiency with lower brake-specific fuel consumption compared to the other teak sawdust pyrolysis oil blends. Meanwhile, the highest engine load was obtained at 50% teak sawdust pyrolysis oil blend and 2600 r/min to be 8 kW. Furthermore, the emissions of CO, CO2, and hydrocarbon at 50% teak sawdust pyrolysis oil and 2000 r/min were slightly lower than other teak sawdust pyrolysis oil blends, no NOx detection in tested fuels, moreover, at 2600 speed, the smoke opacities of the fuels show lower than those the others. It was noted that a blend of 25% teak sawdust pyrolysis oil with diesel was suitable for the small engine (at 2000 r/min) in terms of performance and CO, CO2, and NOX emission for sustainability in agriculture and rural areas.

Modeling and experimental study condenser performance of fixed bed pyrolysis reactor: A case study of solid waste palm starch processing

Sustainable management of vermicelli waste can reduce waste in the environment. In addition, this waste can be used as a renewable fuel source. This study researched the condenser performance concerning the pyrolysis process of biomass from palm starch waste. The solid waste of palm starch was collected from the traditional industry of vermicelli noodles in Klaten District, Indonesia. The solid waste of palm starch formed into RDF-5 biomass. In this research, we use numerical and experimental methods to obtain a performance model of a pyrolysis condenser. The numerical simulation and experiment used different variations of tube models and fluid flow directions. The numerical simulation results show that the helical tube performs better than the concentric tube regarding heat transfer rate and LMTD value. After getting the numerical result, we were going to experiment with three different helical coil-type condenser pipe diameters in the Fixed bed pyrolysis reactor. Based on the experimental results, the condenser with the smallest diameter and parallel flow direction has higher liquid smoke with 41.802% yield production. The pyrolysis of palm starch waste can reduce environmental waste and turn the waste into liquid smoke. However, before it can be used as a bio-diesel additive, the liquid smoke in this research needs to be processed further.

Modelling and optimisation of intermediate pyrolysis synthesis of bio-oil production from palm kernel shell

A Palm Kernel Shell (PKS) is an enclosed shell obtained as residue from processing palm kernel. Its regarded as lignocellulosic biomass that serves as an abundant renewable energy source. The thermal and physicochemical behaviour was investigated, and results showed a low Fixed Carbon (FC) (22.60 wt%), high Volatile Matter (VM) (74.60 wt%), and high Higher Heating Value (HHV) of 19.78 MJ/kg. The elemental results showed the presence of C (48.70 wt%), H (5.58 wt%), N (0.23 wt%), O (45.02 wt%), and S (0.04 wt%). The fixed-bed pyrolysis reactor was utilised for the decomposition of the PKS to produce an optimum bio-oil of 47.10 wt% at temperature (520 °C), reaction time (15 min), nitrogen (175 cm3/min), particle size (0.70 mm), and heating rate (22.5 °C/min). The efficient Response Surface Methodology (RSM) via Central Composite Design (CCD) was employed to model and optimise the operating parameters. P<0.05, a high F-value for bio-oil makes the established model predicted, suitable, responsive, and reliable. The actual and predicted value for the quantity of bio-oil produced showed clearly that the data is reasonably in consonance with the predicted value. Screening with FT-IR revealed that the peak of 3339.7, 1416 cm−1 attributed to O–H stretching vibrations depicted the presence of alcohol and carboxylic acids, respectively, the resent, while the peak at 1636.3, 1274.7 was due to C–H bend and C–O stretch indicating the presence of aromatic compounds and aromatic ester respectively. The most significant element in the bio-oil obtained via Gas Chromatography–Mass Spectrometry (GC–MS) analysis is phenol, 9, 17 – octadecadienoyl, oleic acids, 2-cyclo pentane-1-one, and pent ethylene glycol are the by-products in the sample. Hence, the bio-oil produced is suitable for high-speed diesel engines, vehicle locomotion, powering heavy machines, marine equipment, manufacturing industries, and mining types of machinery. This is a significant contribution in the field of bio-oil production and application.

Possible use of spent FCC catalyst for upgrading of wax from the pyrolysis of plastics to liquid fuel

The cracking of heavy wax derived from mixed plastics (high-density polyethylene, low-density polyethylene, and polypropylene) to chemical and fuel purposes was explored using spent fluid catalytic cracking catalyst (spent FCC). The wax cracking was performed by a fixed-bed pyrolysis reactor with a slow heating rate. All catalysts, when compared to other catalysts (HY zeolite and MCM-41), could enhance liquid oil and gas production. While the spent FCC catalyst produced the highest liquid oil with least amount of coke production. The influence of spent FCC catalyst ratio on product distribution revealed that a catalyst-wax ratio of up to 1:1 resulted in a higher liquid oil yield than a low ratio. Additionally, the increase of cracking temperature promoted more oil production; however, at high temperature (above 400 °C) the evaporation of wax became more significant, and consequently a high portion of produced wax was obtained. Therefore, under suitable conditions, the spent FCC catalyst demonstrated the possibility of upgrading the heavy wax into liquid fuels and chemicals. In addition, this study also compared the products obtained from two processing routes using the spent FCC catalyst. The first route involved the pyrolysis of plastics into wax and then cracking the wax into liquid fuel, while the second route involved a one-step process that directly converted plastics into liquid fuel. The spent FCC catalyst promoted the production of diesel-range hydrocarbons and suppressed the aromatic production for the wax cracking. By contrast, the spent FCC catalyst significantly enhanced aromatic production during the cracking of mixed plastics.

Characterization of Cashew Nut Shell Pyrolysis Liquid: As a Source of Sustainable Energy and a Precursor in many Chemical Industries

20 g cashew nut shell (CNS) was pyrolyzed in a fixed bed pyrolysis reactor at a temperature of 700 °C, heating rate of 100 °C/min, and time of 45 minutes. The cashew nut shell liquid (CNSL) obtained was 61.3 %. Proximate and ultimate analyses, viscosity (cp), density (g/ml), pH, FT-IR, and GC-MS were carried out on the liquid. The results from the GC-MS and FT-IR analyses showed that the liquid consist mainly of aliphatic and aromatic hydrocarbons. The GC-MS analysis showed the different compounds present in this liquid and their relative abundance. From analyses, the liquid had an ash content of 0.06 %, sulphur content of 0.30 %, density of 0.992 g/ml, and a pH of 4.3.

Use of Response Surface Methodology in Optimizing the Production yield of Biofuel from Cashew Nut Shell through the Process of Pyrolysis

A fixed bed pyrolysis reactor was used to pyrolyze Cashew nut shell (CNS). Response Surface Methodology (RSM) was then used to study the pyrolysis process. One Factor at a Time (OFAT) experiment was applied using different factors and levels. The OFAT results showed that the highest pyrolysis liquid yield was 57.8 wt.%. Two levels from each factor were chosen to run the RSM (applying Central Composite Design (CCD)) by forming two levels three factors (23) design. A quadratic model suggested by the Design Expert (version 11) software was used to predict the yield. The maximum liquid yield from the RSM was 61.3 wt. %.

Thermo chemical conversion of cedar wood by pyrolysis technology for bio-oil

The conversion of cedar wood which is abundantly found in the forests of Japan, into biofuels and chemicals by externally heated fixed-bed pyrolysis reactor has been taken into consideration in this study. The selected solid biomass in particle form were fed into the reactor by gravity feed type reactor feeder. The output products were liquid (oil), solid char, and gas. The liquid and char products were collected separately while the gas was flared into the atmosphere. The process conditions were found to influence the product yields significantly. The maximum liquid yields were 48 wt% of solid particles at reactor temperature 450 °C for N2 gas flow rate 6 L/min, feed particle size 1180–1700 µm, and running time 30 min. The liquid product obtained at this optimum condition was characterized by physical properties, chemical analysis, and gas chromatograph mass spectrometry techniques. The results show that it is possible to obtain liquid product from cedar wood that are comparable to petroleum fuels and other valuable chemicals.

Comparative Production of Bio-Oil from In Situ Catalytic Upgrading of Fast Pyrolysis of Lignocellulosic Biomass

Catalytic upgrading of fast pyrolysis bio-oil from two different types of lignocellulosic biomass was conducted using an H-ZSM-5 catalyst at different temperatures. A fixed-bed pyrolysis reactor has been used to perform in situ catalytic pyrolysis experiments at temperatures of 673, 773, and 873 K, where the catalyst (H-ZSM-5) has been mixed with wood chips or lignin, and the pyrolysis and upgrading processes have been performed simultaneously. The fractionation method has been employed to determine the chemical composition of bio-oil samples after catalytic pyrolysis experiments by gas chromatography with mass spectroscopy (GCMS). Other characterization techniques, e.g., water content, viscosity, elemental analysis, pH, and bomb calorimetry have been used, and the obtained results have been compared with the non-catalytic pyrolysis method. The highest bio-oil yield has been reported for bio-oil obtained from softwood at 873 K for both non-catalytic and catalytic bio-oil samples. The results indicate that the main effect of H-ZSM-5 has been observed on the amount of water and oxygen for all bio-oil samples at three different temperatures, where a significant reduction has been achieved compared to non-catalytic bio-oil samples. In addition, a significant viscosity reduction has been reported compared to non-catalytic bio-oil samples, and less viscous bio-oil samples have been produced by catalytic pyrolysis. Furthermore, the obtained results show that the heating values have been increased for upgraded bio-oil samples compared to non-catalytic bio-oil samples. The GCMS analysis of the catalytic bio-oil samples (H-ZSM-5) indicates that toluene and methanol have shown very similar behavior in extracting bio-oil samples in contrast to non-catalytic experiments. However, methanol performed better for extracting chemicals at a higher temperature.

Comparative study on pyrolysis behaviors and chlorine release of pure PVC polymer and commercial PVC plastics

The organic and inorganic additives in PVC plastics cause great difficulties in their actual recycling process, which are different from pure PVC polymer (PVC-PO). In this study, PVC-PO and two commercial PVC plastics were selected and their differences in structure, pyrolysis behavior, chlorine release and migration were compared by FTIR, TG-MS and a fixed-bed pyrolysis reactor. There were more oxygen-containing functional groups and aromatic compounds in the commercial PVC plastics than PVC-PO because of the addition of foaming agents, flame retardants and lubricants. The thermal weight loss of the commercial PVC plastics was divided into three stages due to the decomposition of additives and the releases of CO2 gas, while that of the PVC-PO was two. The pyrolysis tar of two PVC plastics contained 35.72% and 15.71% oxygenated compounds, respectively, while that obtained from PVC-PO contained 96.46% of aromatic compounds. In addition, calcium additives in PVC plastics could promote the cracking of heavy constituents in the volatile, which was favorable for the formation of more light fractions in tar. The pyrolysis gas of PVC-PO was mainly composed of H2 and C1-C4 hydrocarbon gases, while that of PVC plastics contained about 50% of CO2, followed by H2 and hydrocarbon gases. The chlorine content of the PVC-PO (55.88 wt.%) was higher than that of the PVC plastics (13.83 wt.%, 22.77 wt.%). Most of the chlorine in the three PVC samples released as HCl at 220–370 °C, while the peak temperature of dechlorination of the PVC-PO delayed about 8 °C compared to that of PVC plastics and small part of HCl also released at around 475 °C in the pyrolysis of PVC-PO. About 99.90 wt.% of the chlorine was distributed in the gas phase after PVC-PO pyrolysis, while there were 99.85 wt.% and 97.85 wt.% of chlorine was detected in the gas products of two PVC plastics.

Volatile-char interactions during biomass pyrolysis: Effect of biomass acid-washing pretreatment

The purpose of this study is to investigate the effect of acid-washing pretreatment on the poplar wood (PW) pyrolysis under different volatile-char interactions, the experiment was conducted in a self-designed fixed-bed pyrolysis reactor. It was found that acid-washing pretreatment could alter the surface morphology of PW, increase the cellulose crystallinity and reduce the inorganic ash components (mainly Alkali and Alkaline Earth Metal species, AAEMs). AAEMs acted as catalysts for sugar ring fragmentation and charring reactions during both primary pyrolysis of biomass and secondary volatile-char interactions. The removal of AAEMs would increase the bio-oil yield and decrease the biochar and non-condensable gas yields, same trend was also observed with the decreasing volatile-char interactions. The removal of AAEMs and weakened volatile-char interactions both resulted in an increase of C content and a decrease of O content of biochar with more pore structures generated, especially micropores, the content of anhydrosugars in bio-oil was also largely enhanced. In addition, the decrease of volatile-char interactions would significantly reduce the effect of AAEMs in biomass on the pyrolysis process. A highest bio-oil yield of 63.37 wt% with 34.38% of anhydrosugars could be obtained even for a packed fixed-bed reactor by intentionally reducing volatile-char interactions and removing AAEMs from biomass during the process.

CO-PYROLYSIS OF SCRAP TIRES (ST) DAN PLASTIK POLYPROPYLENE (PP): DISTRIBUSI PRODUK DAN PROPERTIS FISIK PYRO-OIL

Plastic waste and scrap tires (ST) have now become pollution that harms the environment in various cities around the world if not managed properly. As pollutants, the two types of waste are actually very interesting to manage because they contain hydrocarbon elements so that they can be processed and have the potential to become alternative fuels. This study aims to determine the effect of co-pyrolysis of scrap tires (ST) and polypropylene (PP) plastic on the distribution of products in the form of oil and char/charcoal. The pyrolysis process was carried out at a temperature of 450℃ for 90 minutes using a fixed bed pyrolysis reactor with ST:PP mixing variations, namely 9:1, 8:2, 7:3, 6:4, and 5:5. The maximum pyrolysis product yield in the form of oil as much as 40.7 Wt% was obtained at a 6:4 mixing variation followed by a 7:3 (36.7 Wt%) mixing variation, then a 5:5 variant (36 Wt%), after that an 8:2 variant (34.3 Wt%) and the last is the 9:1 mixing variation with a total of 28.3 Wt%. For the maximum pyrolysis product in the form of char as much as 42.6 Wt% obtained at 9:1 mixing variation followed by 7:3 mixing variation (41 Wt%) after that 8:2 variant with 38.7 Wt%, then 6:4 with the amount of 27.7 Wt%, and the last is the mixing variation of 5:5 to obtain the char result of 18.3 Wt%. Physical properties of pyro-oil in the form of density and calorific value will also be shown in this study.

Fast pyrolysis of fig leaves: influence of pyrolysis parameters and characterization of bio-oil

Liquid yields achieved by fast pyrolysis of ligno-cellulosic biomass can be used in the production of chemical raw materials or as an energy source. Pyrolysis product yields generally depend on the type of biomass, temperature, retention time, heating rate, sweeping gas flow rate and particle size. In this study, fast pyrolysis of fig leaves selected as biomass was carried out in a fixed bed pyrolysis reactor. Fig leaves used in fast pyrolysis experiments in this study as an agricultural by-product can be obtained in large quantities from Turkey. In the experiments, the effect of temperature, entraining gas flow rate, and particle size on pyrolysis product yields were investigated. The experiments were carried out at 400, 500, 600, 700 °C, four different particle sizes. The highest liquid product yield was obtained at 600 C, while the heating rate was 200 cm3/min and the particle size was

Thermal Decomposition of Medical Wastes in a Fixed-Bed Pyrolysis Reactor

Thermal Decomposition of Medical Wastes in a Fixed-Bed Pyrolysis Reactor

Catalyzed pyrolysis of scrap tires rubber

Every day, a huge volume of scrap tires are produced worldwide, and landfill is an ineffective method of disposing of such hazardous waste. Pyrolysis can be used to convert tire rubber into energy, allowing for the management of such waste in the context of a circular economy. The composition and pyrolysis kinetics of granulated (0.6–0.8 mm) scrap tire rubber (TR) were assessed using thermogravimetry (TG). Data on rubber composition revealed that TG is a quick and accurate technique for determining TR composition. The TG tests with catalysts revealed that using alkali (K, Ca, and Mg) carbonates as catalysts improved the thermal degradation rate. The MgCO3 was able to duplicate the rate of TR thermal degradation. Data from a fixed bed pyrolysis reactor revealed oil yields of around 50% in the 673–773 K temperature range. The effect of alkali carbonate catalysts inferred from TG tests was confirmed by catalyzed pyrolysis tests. The calcium and magnesium carbonate catalysts significantly increased the gas product yield, with the CaCO3 catalyst having the greatest drop in oil yield due to likely secondary pyrolysis processes. Because of the low pyrolysis temperature, the acidic catalysts (SiO2, TiO2, Al2O3, and montmorillonite) had almost no effect on the pyrolysis product distribution. For all of the catalysts used, the ATR-FTIR spectra of the produced oils exhibited characteristics similar to those of diesel fuel. Data showed that alkali carbonate catalysts (mainly Mg and Ca), cheap and environmentally benign materials, can be used to tailor the TR pyrolysis products distribution allowing a more profitable process.

Co-pyrolysis kinetics and pyrolysis product distribution of various tannery wastes

Tanning sludge, chrome tanned buffing dust and chrome shavings were selected as experimental materials. The non-isothermal distributed activation energy model (DAEM) was used to study the pyrolysis kinetic parameters. Effects of particle size and temperature on distribution of co-pyrolysis products of various tanning wastes were investigated in a fixed-bed pyrolysis reactor, which provided a new approach for comprehensive thermal treatment of various tannery wastes. The results show that the total activation energy required for the co-pyrolysis decreases and then increases in the range of conversion rate of 0.1 to 0.8. The tar yield decreases with raising particle size, while the yields of gas and char increase. With increasing pyrolysis temperature, the tar yield increases rapidly to a peak value of 17% at 600°C, and then decreases, correspondingly the char yield decreases while the gas yield increases. At 600°C and the particle size of 1.6–2.5 mm, specific surface area of the char is larger, and the light fractions in tar is higher. Thus, co-pyrolysis is conducive to clean treatment of the tannery wastes.

Novel insights into the enrichment of phenols from walnut shell pyrolysis loop: Torrefaction coupled fractional condensation.

Enriching high-value chemicals from the pyrolysis of agricultural and forestry waste is an efficient way to achieve sustainable development and large-scale application of biomass pyrolysis. Phenols, as important chemical raw materials, spices and food additives, have attracted widespread attention. Herein, a novel technical route of torrefaction pretreatment combined with fractional condensation in pyrolysis loop was proposed to enrich the phenols in liquid products. In this study, the enrichment of phenols from the pyrolysis loop of walnut shell under the combination of torrefaction and fractional condensation was explored using a fixed-bed pyrolysis reactor equipped with a three-stage condensation system. Simultaneously, the effects of torrefaction on feedstocks were investigated through a thermogravimetric analyzer based on the characteristics of feedstocks. The results showed that the torrefaction and pyrolysis loop had a negative impact on the pyrolysis efficiency and the yield of liquid products, while the change in the condensation efficiency depended on the combined effects of torrefaction and pyrolysis loop. In addition, phenols tended to be enriched in the second condensation stage, especially phenol, o-cresol, 4-ethylphenol. Importantly, torrefaction could significantly enrich phenols in the liquid products, and the enrichment of phenols is relatively increased by 109.44% at least. Moreover, the pyrolysis loop was also beneficial to the enrichment of phenols, which was at least 90% higher than that of walnut shell. This study provided a potential route to enrich high value-added products from the pyrolysis loop of lignocellulosic biomass.