Pyrolysis Vapors Research Articles

Visual liquefaction process of biomass pyrolysis vapors during indirect heat exchange: Experimental description, prediction, and verification

The present investigation proposed an experimental method combining bio-oil segmental recovery, vapor composition inversion, and function fitting, to describe the vapor evolution curves and heat maps of water, acetic acid, furfural, phenol, MCP, guaiacol and its derivatives in the indirect condensing field regulated by continuous water bath temperatures within 280–364 K. Under 280 K water bath, the recovery proportion of water exceeded 50 % after pyrolysis vapors moved 8 cm from inlet, and soon surpassed 90 % after 12.5 cm. At 337 K, 50 % recovery proportion of water required the vapors to move 20 cm, while guaiacol required only 10 cm for the same proportion. Half of the evolution description data were sampled and utilized to fit the prediction curves of vapor evolution with increasing bath temperature, and another half were used to verify these prediction curves. The overall prediction accuracy of the representative components remained at 70 %, despite the local accuracies less than 50 % within 280–300 K and 355–364 K. These findings provided a visual description and prediction method for the selective condensation of pyrolysis vapors. The cycle from research to application of selective condensation was effectively shortened by the prediction of vapor evolution under water bath based on sampling experiments.

From cassava peel (Manihot esculenta) to hydrocarbon-rich bio-oil: Catalytic flash pyrolysis as a new valorization route

The valorization of agroindustrial residues for second-generation biofuels has garnered attention due to the increasing demand for low-carbon fuels aligned with transportation sector decarbonization efforts. In this context, cassava processing residues, particularly cassava peel, remain largely unexplored but offer a cheap, abundant, and renewable feedstock that can be converted into hydrocarbon-rich biofuel. Thus, the originality of this study lies in investigating the selective conversion of cassava peel into renewable aromatic hydrocarbons through flash pyrolysis catalyzed by an environmentally friendly MFI-type zeolite synthesized from rice husk ash and diatomite residue. A micro-pyrolyzer interfaced with chromatographic separation and mass spectrometry detection was used to compare the composition of condensable volatile products from catalytic pyrolysis over HZSM-5 with those from catalyst-free pyrolysis. Cassava peel, characterized by high volatile matter content (84.3 %), low ash content (3.19 %), and reasonable energy content (15 MJ kg −1), yielded a high content of valuable platform chemicals, such as carboxylic acids and furans, when subjected to catalyst-free pyrolysis. The catalytic upgrading pyrolysis vapors over the environmentally friendly HZSM-5 catalyst yielded approximately 56.0 % industrially relevant aromatic hydrocarbons and 39.9 % light organic acids. Other strengths of using HZSM-5 in upgrading pyrolysis vapors were its low selectivity for naphthalenes, precursors for coke formation, and the production of hydrocarbons in the gasoline range. Thus, HZSM-5 was an efficient catalyst for promoting deoxygenation and improving hydrocarbon content, with high selectivity for valuable aromatic hydrocarbons. In conclusion, cassava peel showed favorable prospects for conversion into hydrocarbon-rich bio-oil, serving as a valuable precursor for low-carbon biofuels.

Effects of porosity and acidity on deoxygenation and denitrogenation in catalytic pyrolysis of protein-rich microalgae with metal-doped zeolites

The protein-rich defatted microalgae (Nannochloropsis gaditana) after lipid extraction was used as feedstock in catalytic pyrolysis to optimize economic returns of microalgae waste utilization. The effects of Ni- and Co-modified HZSM-5 on the formation of aromatic hydrocarbons (AHs), deoxygenation and denitrogenation in catalytic fast pyrolysis were studied via pyrolysis-gas chromatography and mass spectrometry (Py-GC/MS) at 500°C. Monometallic modified catalysts were synthesized by loading 0.5 wt%, 1 wt%, and 2 wt% of metal species onto HZSM-5 using ion exchange methods. The composition and pyrolysis pathways of primary volatiles detectable by gas chromatography (GC) were investigated, which included phenols, aliphatic hydrocarbons, AHs, acids, furans, N-heterocyclic compounds (N-HCs), amides and nitriles. The relative yields in AHs increased about 10.9 (0.5 wt% Ni/HZSM-5 or Ni0.5), 10.2 (Ni1), 6.8 (Ni2), 7.3 (Co0.5), 9.7 (Co1) and 7.8 (Co2) times compared to the relative yield from defatted microalgae pyrolysis. The doping of metals onto the HZSM-5 altered its porosity and acidity, leading to an impaired diffusion of reactants but also the creation of new acidic sites, which enhanced the selectivity towards monoaromatic hydrocarbons (MAHs) by aromatization and cleavage of N-containing heterocycles via the H radicals formation. Ni-loaded HZSM-5 outperformed Co-modified zeolite with respect to AHs production, deoxygenation and denitrogenation. The specific surface area (SBET) and pore volume were positively correlated with the formation of AHs, while strong acidity showed a strong positive correlation with the generation of nitriles and N-HCs. Relatively low loadings of Ni and Co (0.5–1 wt%) on HZSM-5 (Si/Al = 23) were recommended to decrease the N-containing compounds in pyrolysis vapors from defatted microalgae. The findings may shed light on the development of a high-performance HZSM-5 catalyst for the production of AHs and denitrogenation from protein-rich defatted microalgae.

Biomass Valorization through Catalytic Pyrolysis Using Metal-Impregnated Natural Zeolites: From Waste to Resources.

Catalytic biomass pyrolysis is one of the most promising routes for obtaining bio-sustainable products that replace petroleum derivatives. This study evaluates the production of aromatic compounds (benzene, toluene, and xylene (BTX)) from the catalytic pyrolysis of lignocellulosic biomass (Pinus radiata (PR) and Eucalyptus globulus (EG)). Chilean natural zeolite (NZ) was used as a catalyst for pyrolysis reactions, which was modified by double ion exchange (H2NZ) and transition metals impregnation (Cu5H2NZ and Ni5H2NZ). The catalysts were characterized by nitrogen adsorption, X-ray diffraction (XRD), ammonium programmed desorption (TPD-NH3), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). Analytical pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS) allowed us to study the influence of natural and modified zeolite catalysts on BTX production. XRD analysis confirmed the presence of metal oxides (CuO and NiO) in the zeolite framework, and SEM-EDS confirmed successful metal impregnation (6.20% for Cu5H2NZ and 6.97% for Ni5H2NZ). Py-GC/MS revealed a reduction in oxygenated compounds such as esters, ketones, and phenols, along with an increase in aromatic compounds in PR from 2.92% w/w (without catalyst) to 20.89% w/w with Ni5H2NZ at a biomass/catalyst ratio of 1/5, and in EG from 2.69% w/w (without catalyst) to 30.53% w/w with Ni5H2NZ at a biomass/catalyst ratio of 1/2.5. These increases can be attributed to acidic sites within the catalyst pores or on their surface, facilitating deoxygenation reactions such as dehydration, decarboxylation, decarbonylation, aldol condensation, and aromatization. Overall, this study demonstrated that the catalytic biomass pyrolysis process using Chilean natural zeolite modified with double ion exchange and impregnated with transition metals (Cu and Ni) could be highly advantageous for achieving significant conversion of oxygenated compounds into hydrocarbons and, consequently, improving the quality of the condensed pyrolysis vapors.

Pyrolysis of metal oxides treated Canarium schweinfurthii Shell: Investigation of thermogravimetric kinetics and thermodynamics

Metal oxides as catalysts alter the properties of the pyrolysis vapor secondary reactions during the thermal decomposition of several biomass leading to high-value bio-oils. This study aimed to investigate the thermal decomposition characteristics of Canarium Schweinfurthii (CS) shells that were treated with various metal oxides (ZnO, CuO, Fe2O3/FeO, and Fe2O3) using pyrolysis. The study also sought to identify pyrolysis reaction parameters (kinetics and thermodynamics parameters) that are not widely documented. Thermogravimetric pyrolysis was carried out at different heating rates, and the undocumented pyrolysis kinetic parameters were determined using the Flynn-Wall Ozawa method (FWO) according to American Standard Testing and Materials (ASTM) 6441 guidelines for assessing biomass decomposition. The metal oxide-treated CS shells lost significant weight between 62 and 67 wt% during the thermogravimetric pyrolysis, lower than 75 wt% of the CS shell. The average activation energies (Eα) for pyrolysis of the ZnO, CuO, Fe2O3/FeO, and Fe2O3 treated CS shells were 203.04, 155.35, 338.85, and 219.92 kJ/mol, respectively in contrast to that of the untreated CS-shell. The Bayesian Information Criteria revealed that the diffusion kinetics of the Gistling-Brounshtein model best describes the pyrolysis of the shell mixed with metal oxides. The metal oxides affected the CS shells' pyrolysis kinetic parameter (Eα), which can promote pyrolysis vapor upgrading to encourage the widespread use of metal oxides in pyrolysis for bioenergy and chemical recovery.

The effects of in situ-produced hydrogen on catalytic upgrading of lignite pyrolysis volatiles over ZSM-5 zeolites to produce light aromatics

The introduction of in situ hydrogen donors to obtain a high H/Ceff ratio is an effective way to upgrade coal pyrolysis volatiles to light aromatics. In this study, the influence of different in-situ hydrogen suppliers in catalytic reforming of coal pyrolysis vapors was explored. The abilities of active hydrogen donation were greatly corresponded to structures of hydrogen donors. Isopropanol showed the best catalytic performance due to the release of a large amount of active α-H as a result of negative inductive effect of hydroxyl. Whereas tertbutanol showed the poorest catalytic performance owing to the lack of α-H. Meanwhile, the effect of in-situ hydrogen production via steam reforming with different alcohols on light aromatic yields was investigated. The highest BTEXN yield was obtained under in-situ hydrogen production from isopropanol steam reforming. Two circumstances of hydrogen supply were further compared. Relatively higher BTEXN yield was presented in the reaction of methanol steam reforming than that of using methanol solely. However, higher BTEXN yield was contrarily obtained from sole isopropanol as a hydrogen donor despite lower H2 production was gained compared to the case of isopropanol steam reforming. The fact was probably ascribed that high electron-withdrawing effect of hydroxyl for isopropanol promoted the cleavage of α-C-H bond and favored the transfer of active hydrogen to reactants over acid sites.

Pyrolysis and catalytic upgrading of pine wood sawdust over modified biochar catalyst in a tandem microreactor

A series of novel catalysts were prepared by modifying biochar (BC) with different metal loading (Fe, Zn) and thermal activation in different atmospheres (CO2, H2O). The catalysts were further used to upgrade the pyrolysis vapor from pine wood sawdust, aiming to produce high-quality bio-oil. The modified biochar catalyst exhibited strong deoxygenation ability to acids and ketones in bio-oil and effectively converted lignin-derived compounds into aromatic hydrocarbons and phenols. Subsequently, the catalyst (BC-Fe-CO2) demonstrating the highest yields of phenols and aromatics was selected for condition optimization. Different catalytic temperatures and biomass-to-catalyst ratios were compared to determine the optimal conditions for producing high-quality bio-oil. Phenolics and aromatic hydrocarbons content in the bio-oil reached 70 % at the optimal condition and the selectivity of monocyclic aromatic hydrocarbons in aromatic hydrocarbons reached 77 %. The properties of the biochar catalysts were characterized using BET, SEM, XRD, and XPS. The superior performance of the modified BC catalysts not only relied on its enhanced surface area and porous structure but also due to active Fe sites. The detail reaction pathways of the bio-oil catalytic upgrading were also proposed. These findings underscore the potential of modified biochar in pyrolysis and catalytic upgrading for bio-oil with improved quality.

Investigation of products characteristics from microwave catalytic pyrolysis of furfural residue based on the effects of Fe/Mn modified biochar

In this paper, the effect of MnCl2 and FeCl3 modified biochar catalysts on the catalytic pyrolysis products of furfural residue (FR) under microwave field was investigated. The results showed that the highest content in the pyrolysis gas obtained from microwave catalytic pyrolysis (MCP) with modified biochar catalysts was CO, while phenols were found in bio-oil. After metal loading, the specific surface area of the catalyst decreased significantly. The CO production was promoted by microwave pyrolysis of FR over modified biochar catalyst, and MFRC gain was more obvious. The content of H2 all continued to increase with increasing mass of loaded metals, and the opposite was true for CO. The highest relative content of phenols in the bio-oils of FFRC and MFRC were 66.76 % for 2FFRC and 63.66 % for 4MFRC, where the relative content of phenols was 15.50 % and 19.27 %, respectively. The production of sugars and ketones was also promoted by Fe and Mn. The lower loading of active metals significantly promoted the conversion of pyrolysis vapors to phenols while releasing more CO. A possible mechanism of MCP of FR was proposed. The results showed that Fe/Mn-modified char-based catalysts could effectively modulate the composition of bio-oil.

Tailored HZSM-5 catalyst modification via phosphorus impregnation and mesopore introduction for selective catalytic conversion of polypropylene into light olefins

The waste polyolefin composition varies regionally due to different sorting technologies, emphasizing the necessity for a robust catalyst capable of selectively converting pyrolysis vapors into valuable light olefins while maintaining stability. HZSM-5, a microporous catalyst, efficiently cracks polyethylene (PE) pyrolysis vapors rich in linear aliphatics. However, polypropylene (PP) pyrolysis typically yields branched olefins, potentially hindering effectiveness of HZSM-5 due to mass transfer constraints and coke blockage in micropores. This study modifies HZSM-5 through phosphorus impregnation, mesopore introduction, and steam treatment to evaluate the impact of acidity, pore size, and surface modifications on catalyst stability and light olefin selectivity during PP pyrolysis vapor cracking. Subsequent experiments reveal the superior stability of modified catalysts. Phosphorus-modified (P-HZSM-5ss) and mesoporous phosphorus-modified (P-mesoHZSM-5ss) catalysts retain 72 % and 80 % of their initial activity after 150 runs, respectively, while the parent HZSM-5 experiences a rapid 44 % activity loss. P-mesoHZSM-5ss demonstrates the highest light olefin selectivity (63 wt%) after 150 runs, attributed to improved accessibility of branched olefinic products to active sites within catalyst pores. Further optimization achieves exceptional light olefin selectivity of 84 wt% at 117 ms contact time and 550 °C, surpassing maximum selectivity of the parent catalyst. Comparative analyses of PP, PE, and mixed polyolefinic waste pyrolysis vapor cracking revealed the influence of polyolefin type on optimal operational conditions, stressing the need for flexibility in operating conditions to scale up the proposed polyolefin recycling method. This study highlights the potential of tailored catalyst modifications and process optimization to efficiently convert PP into valuable light olefins, advancing sustainable polyolefin recycling technologies.

Catalytic pyrolysis of corncob residues and pubescens over pristine and alkalis-treated HZSM-5

The catalytic pyrolysis of corncob residues and pubescens was carried out using HZSM-5 and alkalis-treated HZSM-5 as catalysts. HZSM-5 treated with different alkalis (TPAOH and a mixture of NaOH and Na2CO3) to get TPHZSM-5 and DHZSM-5. It was shown that the acid sites of the DHZSM-5 and TPHZSM-5 catalyst decreased compared to pristine HZSM-5. The hierarchical structures combining micro- and meso- porosity was formed in DHZSM-5, which was more conducive to promoting the formation of mono-phenols. However, the pore size of the catalyst decreased and the strength strong acid site increased with TPAOH treatment, which was beneficial for promoting C-O bond cleavage and generating more monocyclic aromatic hydrocarbons (MAHs). Under the same conditions, HZSM-5 was most beneficial for improving the yield of bio-oil (45.9 wt% of corncob residues and 52.0 wt% of pubescens). Analysis of the bio-oil showed that the catalytic pyrolysis of biomass over HZSM-5 achieved the highest PAHs yield (31.45 % from corncob residues and 18.38 % from pubescens), while TPHZSM-5 obtained the highest MAHs yield (5.92 % from corncob residues and 2.03 % from pubescens). However, DHZSM-5 catalyst appeared to have no significant effect on the increase of MAHs and PAHs yield, which may be attributed to its promotion of secondary polymerization of pyrolysis products. Additionally, the catalyst promoted the secondary cracking of pyrolysis vapor and reduced the average molecular weight (Mn) of the bio-oil. DHZSM-5 and TPHZSM-5 catalysts offered significant potential for the valorization of lignin, facilitating the production of value-added mono-phenolic compounds, MAHs, and high-quality fuels.

Performance of Motorcycle Fueled with Pertalite‒LDPE Pyrolytic Oil Blendings

Plastic use has expanded substantially, and its waste is primarily disposed of in landfills, which further harm ecosystems owing to inadequate waste management. Pyrolysis, which converts plastic waste into liquid fuel, is one of the potential chemical recycling alternatives for plastic. The purpose of this study is to determine the viability of using pyrolytic oil from an LDPE grocery bag as an alternative fuel for a four-stroke spark ignition motorcycle engine. The LDPE grocery bag was pyrolyzed at 500 oC at a heating rate of 3 oC/min, and the condensed pyrolytic vapor's characteristics were determined. Torque, power, and fuel consumption were investigated using a four-stroke spark ignition motorbike powered by pertalite‒LDPE pyrolytic oil blends. The results reveal that the properties of LDPE pyrolytic oil and pertalite were considerably different; hence, when the blending fuel was applied to the motorcycle, the engine torque and power decreased at low engine speed (2000‒3500 rpm), about equal at medium speed (3500‒5500 rpm), and increased at high engine speed (5500‒8500 rpm). Furthermore, the greater blending fuel greatly reduced fuel usage due to the high viscosity of the LDPE pyrolytic oil.

Enhancement of selective monoaromatic hydrocarbon and syngas products from fast pyrolysis of cassava stalks over Co, Mo promoted Ni catalysts

Catalytic fast pyrolysis of cassava stalks has been intriguing as a promising, feasible chemical refinery method in terms of waste-to-energy conversion from cassava cultivation. This study aims to determine the synergetic influence of Mo and Co on Ni catalysts (Ni, Ni–Mo, and Ni–Co) prepared via ultrasonic-assisted incipient wetness impregnation method for catalytic pyrolysis vapor upgrading. The results indicated that Co and Mo enhance the reducibility of NiO and promote weak-to-medium acidity, thereby enhancing Ni's performance. Mono-Ni favors cracking deoxygenation, whereas oxophilicity promoters particularly enhance the oxygen absorbability efficiency to selective deoxygenated production. A fine Ni dispersion on CoNi/SiO2 catalyst was observed to positively affect the production of monoaromatic hydrocarbons (46.10 %), in contrast to those without promoters (21.63 %). This is attributed to an optimal Ni-metallic distribution with a small crystal size of 7.01 nm and a high surface area of 342.6 m2 g−1, highlighting the effectiveness of the promoter-assisted Ni catalyst. Additionally, a high yield of H2 (66.9 %) in non-condensable gas was recorded at 550 °C. The study suggests that a simplified approach to developing Ni-based catalysts could enhance the eco-friendliness of commercial catalysts, thereby facilitating the scale-up of biomass pyrolysis applications.

Catalytic hydropyrolysis of cashew de-oiled shell using Py-GC/MS

The present study delves into the impact of different metal oxides (Al2O3, Nb2O5, CaO, CeO2, and ZrO2) and temperatures (350, 450, and 550℃) on the flash pyrolysis of cashew de-oiled shell. Upon analysis using Pyrolysis Gas Chromatography and Mass Spectrometry (Py-GC/MS), the resulting functionalities, including carbonyls, furans, phenolics, hydrocarbons, sugars, and N-containing compounds, have been identified. Additionally, the potential of flash hydro-pyrolysis to upgrade pyrolysis vapors into fuel-grade hydrocarbons has also been studied. The study investigates the effect of hydrogen pressure variations (1, 5, and 10 bar) and the catalytic activity of metal oxides on hydropyrolysis. Characterization of the metal oxides through BET, XRD, SEM, and TPD reveals distinct properties. Notably, incorporating Al2O3 significantly enhances the production of aliphatic hydrocarbons, reaching 78.4 area% at 10 bar of hydrogen. This research advances our understanding of flash pyrolysis and provides insights into sustainable fuel production through targeted catalytic processes.

Novel Staged Free-Fall Reactor for the (Catalytic) Pyrolysis of Lignocellulosic Biomass and Waste Plastics.

Pyrolysis of lignocellulosic biomass and waste plastics has been intensely studied in the last few decades to obtain renewable fuels and chemicals. Various pyrolysis devices have been developed for use in a laboratory setting, operated either in batch or continuously at scales ranging from milligrams per hour to tenths of g per hour. We report here the design and operation of a novel staged free-fall (catalytic) pyrolysis unit and demonstrate that the concept works very well for the (catalytic) pyrolysis of pinewood sawdust, paper sludge, and polypropylene as representative feeds. The unit consists of a vertical tube with a pretreatment section, a pyrolysis section, a solid residue collection section, a gas-liquid separation/collection section, and a catalytic reaction section to optionally perform ex situ catalytic upgrading of the pyrolysis vapor. The sample is placed in a tube, which is transported by gravity through various sections of the unit. It allows for rapid testing with semicontinuous feeding (e.g., 50 g h-1) and the opportunity to perform reactions under an (inert) gas (e.g., N2) at atmospheric as well as elevated pressure (e.g., 50 bar). Liquid yields for noncatalytic sawdust pyrolysis at optimized conditions (475 °C and atmospheric pressure) were 63 wt % on biomass intake. A lower yield of 51 wt % (on a biomass basis) was obtained for the noncatalytic pyrolysis of paper sludge, likely due to the presence of minerals (e.g., CaCO3) in the feed. The possibility of using the unit for ex situ catalytic pyrolysis (pyrolysis at 475 °C and catalytic upgrading at 550 °C) was also successfully demonstrated using paper sludge as the feed and H-ZSM-5 as the catalyst (21 wt % catalyst on biomass). This resulted in a biphasic liquid product with 25.6 wt % of an aqueous phase and 11 wt % of an oil phase. The yield of benzene, toluene, and xylenes was 1.9 wt % (on a biomass basis). Finally, the concept was also proven for a representative polyolefin (polypropylene), both noncatalytic as well as in situ catalytic pyrolysis using H-ZSM-5 as the catalyst at 500 °C. The liquid yield of thermal, noncatalytic plastic pyrolysis was as high as 77 wt % on plastic intake, while in situ catalytic pyrolysis gave a combined 7.8 wt % yield of benzene, toluene, and xylenes on plastic intake.

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

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

Asphalt pyro-rejuvenators based on waste tyres: An approach to improve the rheological and self-healing properties of aged binders

Waste Tyres (WT) are a significant fraction of industrial waste and a source of environmental hazards with limited valorisation. To reduce this problem, currently there is a growing interest in valuing the WT through pyrolysis to obtain multifunctional liquids to improve the rheological and self-healing properties of aged binders. This research provides a comprehensive study on using WT mixtures as precursors for asphalt rejuvenators by means of pyrolysis and distillation processes. To this end, WT polymeric fractions from light (WT-L) and mining trucks (WT-M) were used as feedstock and characterised for compositional and thermal properties. Additionally, micropyrolysis coupled with gas chromatography/mass spectrometry (Py-GC-MS) was used to identify the major products in pyrolysis vapours, to elucidate the reaction maps describing thermal degradation of WTs and to predict the feasible reaction conditions. The pyrolysis liquids were produced after a screening of reaction conditions and subjected to distillation, following a response surface model to produce an optimised pyro-rejuvenator. The results showed that the pyrolytic rejuvenator obtained through pyrolysis at 465 °C and distillation cutting at 160–200 °C is mainly composed of hydrocarbons and aromatic substances (95.5%), with a significant proportion of limonene (33.71%). Furthermore, the pyrolytic rejuvenator exhibited highly desirable physical properties in the context of its application and excellent oxidative stability (85.7%). Otherwise, it was determined that bitumen mixtures with 3%–6% doses of pyro-rejuvenator improved the viscosity, softening point, and penetration of aged binders, restoring their physical properties to the virgin state. In conclusion, pyro-rejuvenators can be successfully used as a promising solution to produce more durable and sustainable pavements with improved rheological and healing properties.

Study on the effect of transition zone-condensation field for the evolution and selective condensation of biomass pyrolysis vapors

The effect of regulating the transition zone temperature and the intensity of the condensation field on the characteristic parameters and important components of bio-oil was studied during the pyrolysis of cotton straw. A new approach was provided to improve the possibility for refined condensation of biomass pyrolysis vapors, increase the bio-oil yield and recovery of important components. The Logistic model effectively tracked the evolution of the characteristic components of the bio-oil and comprehensively demonstrated the selective condensation effect of the biomass pyrolysis vapors. It was found that higher transition zone temperatures improved pyrolysis vapors condensation. The temperature gradient affected the content of important components in bio-oil. Adjusting the transition zone temperature promoted the initial separation of unfavorable components such as water in the bio-oil, and the enrichment of critical organic components was achieved in combination with the condensation field. The high transition zone temperature and weak condensation field contributed to an increase in the recovery of total phenolic compounds from 0.69 wt% to 8.20 wt%.

Co-production of biochar and carbon nanotube from sewage sludge in a two-stage process coupling pyrolysis and catalytic chemical vapor deposition

Co-production of biochar and carbon nanotube from sewage sludge in a two-stage process coupling pyrolysis and catalytic chemical vapor deposition

Cooperative production of monophenolic chemicals and carbon adsorption materials from cascade pyrolysis of acid hydrolysis lignin

A novel cascade pyrolysis upgrading process for acid hydrolysis lignin (AHL), consisting of pyrolysis, catalytic upgrading of pyrolysis vapors, and pyrolysis char, was developed to improve the yield of value-added products (monophenolic chemicals and carbon materials). Pyrolysis of AHL at 450 °C and subsequent catalytic upgrading of pyrolysis vapors over Ni/H-ZSM-5 boosted the concentration of monophenolic chemicals in pyrolysis liquids by 58%. The carbon material prepared from pyrolysis char using KOH as activating agent exhibited a large specific surface area of 2902.5 m2/g and a large total pore volume of 1.45 cm3/g, thus affording good adsorption capacity for methylene blue (824.87 mg/g) and iodine (2333.17 mg/g). Moreover, the cascade pyrolysis upgrading of AHL achieved a yield of 68.52% desired products, which was much higher than the reported results (single production of monophenols and pyrolysis char). In summary, this work provides a potential reference for efficient utilization of lignin in large-scale applications.

Catalytic Upgrading of Pyrolysis Vapors from Scenedesmus sp. Microalgae towards Renewable Hydrocarbons using a Low-Cost Zeolite Synthesized from Rice Husk Ash and Diatomite Residue

Catalytic Upgrading of Pyrolysis Vapors from Scenedesmus sp. Microalgae towards Renewable Hydrocarbons using a Low-Cost Zeolite Synthesized from Rice Husk Ash and Diatomite Residue