Study Of Pyrolysis Research Articles

Spectroscopic characterization of radicals formed by hydrogen-atom abstraction from γ-valerolactone and γ-butyrolactone.

γ-valerolactone (GVL) and its unmethylated counterpart, γ-butyrolactone (GBL), are important compounds with a wide range of potential uses. For example, GVL is proposed as an ideal alternative renewable energy source, while GBL can be utilized as an electrolyte. Understanding the combustion mechanisms of these compounds is crucial for optimizing their use as energy sources and monitoring the products formed during combustion. During pyrolysis, reactions with hydrogen atoms play a key role. Although the reactions of lactones with hydrogen atoms have been studied at higher temperatures using theoretical and computational methods, the spectroscopic data for the radicals produced during these reactions remain incomplete. Such data could, however, be valuable for tracking radical mechanisms. This study investigated these reactions at 3.1 K using the para-H2 matrix-isolation technique. The conditions provided by this method are particularly well-suited for studying radicals, in contrast to the conditions used in pyrolysis studies. IR spectroscopy was employed to monitor the reactions, enabling us to observe the vibrational spectra of the resulting radicals. These spectroscopic data could offer valuable insights for further exploring the combustion processes of GVL and GBL.

Techno-economic, exergetic, and life cycle assessment of clean hydrogen production methods using renewable energy: A comparative study of e-methane pyrolysis, e-steam methane reforming, and alkaline water electrolysis

Techno-economic, exergetic, and life cycle assessment of clean hydrogen production methods using renewable energy: A comparative study of e-methane pyrolysis, e-steam methane reforming, and alkaline water electrolysis

Towards an eco-social circular economy: exploring the feasibility study of pyrolysis on agricultural feedstocks

AbstractThe agricultural sector is challenging to decarbonise due to its reliance on heavy machinery and fossil fuels, which face issues when decarbonising via methods such as electrification. However, agriculture provides opportunities to generate renewable energy via biomass sources due to their abundance within this sector. This feasibility study used a continuous auger pyrolysis system to assess how straw waste from a medium-scale arable farm could convert energy from an external electrical source into usable chemical potential. Wheat, barley, oil seed rape (OSR), and bean straw have all been processed and pyrolysed under different temperatures and auger feed rates. The syngas product was then analysed, considering its composition and the lower heating value. Results indicate that the percentage of carbon monoxide and hydrogen and the total volume of syngas increased with temperature. In addition, the syngas’ energy quantity increased despite the product’s decreasing heating value. The case study’s annual energy demand was equal to 14.4% of the 3900 GJ maximum potential contained within the syngas, and thus it can be concluded that there is potential for the application of this system towards a circular economy. The system’s cold gas, net, and electrical conversion efficiency were also assessed with maximum values of 37.1%, 30.1%, and 174.4%, respectively. Furthermore, the statistical analysis confirms high predictability for wheat, barley, bean, and OSR feedstocks, with a general linear model showing high accuracy across all.

Hydrocarbon potential, source correlation, and paleoenvironmental reconstruction of the Jurassic interval in the Zey Gawra Oilfield, Kurdistan Region, Iraq

A comprehensive geochemical analysis for the Sargelu, Naokelekan, and Najmah formations cutting rock and crude oil samples from Z1, Z3, and Z5 wells of Hawler Block, Kurdistan Region, Iraq have been studied for source rock evaluation. Depending on the total organic carbon (TOC) content from pyrolysis analyses, the Sargelu and Naokelekan formations are regarded as very good source rocks, and fair source rock for the Najmah Formation. The organic matter in the Sargelu Formation is characterized by types II and mixed II and III kerogens. However, the Naokelekan and Najmah formations are characterized by type II kerogen. The Sargelu and Naokelekan formations’ organic matters are at mature stages; hence, in the oil window, whereas Najmah Formation’s organic matter is at immature stage. Pyrolysis study shows that the Sargelu Formation is oil and gas prone, while the Najmah and Naokelekan formations are oil prone. The biomarkers and bulk properties of the selected oils from Gas Chromatography (GC) and Gas Chromatography-Mass Spectroscopy (GC/MS) analysis show that they originated by the same source rocks. The geochemical characteristics indicate a carbonate source in a reducing environment for the studied formations and oils. Based on the oleanane index, tricyclic terpane indices, C28S/C29S ratios, and gammacerane index, the relative age of the oils and cuttings of Sargelu, Naokelekan, and Najmah formations is Middle to Late Jurassic and deposited under moderate saline condition. The biomarkers parameters show evidence that molecules from the cutting rocks of the Sargelu and Naokelekan formations are related to the oils in Z1, Z3, and Z5 wells. However, they are not related to the Najmah Formation.

New insights into typical biodegradable plastics in rapid pyrolysis: Kinetics, product evolution and transformation mechanism

Biodegradable plastics (BP) have undergone rapid development in the field of replacing traditional packaging plastics. However, their recycling and disposal systems are unclear, and the standards are different, causing new environmental pollution. The rapid and appropriate disposal of BP has become a worthy direction of exploration. Here, rapid pyrolysis technology was used to explore the recycling of BP, and the product evolution and transformation mechanism of typical BP (BP1∼BP4) were analyzed. The results show that the main reaction stages of BP pyrolysis are concentrated at approximately 260∼450 °C. Most of the heat treatment stages of BP conform to the random nucleation and nuclear growth model An (n = 1.5, 2, 2.5. 3). The gaseous products of BP pyrolysis were mainly 1, 3-butadiene. The top four pyrolysis components are the same for the liquid products of BP1, BP2, and BP4, which are mainly benzoic acid (42.54%–44.67%). However, the proportion of polycyclic aromatic substances in the products of the BP3 pyrolysis solution was as high as 63.85%. For the transformation mechanism, BP containing polylactic acid (PLA) and polybutylene terephthalate-adipate (PBAT) is mainly composed of C–O bond fractures at the ester group and intramolecular hydrogen transfer to form a carboxyl group and CC. This study of BP pyrolysis provides an important scientific basis and theoretical reference for its rational and rapid treatment and product recovery and reuse.

Textile waste pyrolysis: an innovative method for petrochemicals generation for sustainable economic, technological and environmental advancement.

The disposal of wastes into landfills, which has worsened the ecosystem, has made textile waste in the third world a major environmental problem. Textile waste is an environmental hazard as it biodegrades quickly and is improperly disposed of. This research is a demonstration of the study and application of textile waste pyrolysis as an innovative method for petrochemical generation for sustainable economic, technological and environmental advancement. The researchers converted textile waste (TEXW) into petrochemicals using pyrolysis. The obtained petrochemicals were fractionated after purification and characterisation using GC-MS while the physicochemical parameters of the fractionated liquid petrochemicals were analysed using standard methods. The results of the analysis showed that the liquid oil contains: carbamate (7.69%), silicic acid (4.73%), cyclotrisiloxane (4.09%), cyclohexane (7.47%), pro-2-ynyl-E-2-methylbut-2-enote (6.24%), cyclododecanol (3.95%), undec-10-ynoic acid (3.95%), 8,8-dimethylspirol-4,6-undecane-6,10-dione (3.47%), phenol (5.95%) and 1,2,5-oxadiazol-3-amine (3.85%). The results of the physico-chemical parameters of the liquid petrochemicals ranged: relative density (0.4250-0.8528 g/cm3), absolute viscosity (0.3436-0.8788 mPas), kinematic viscosity (0.4097-3.880 mm2/s), specific gravity at 15/15 °C (0.8528-0.9556kg/m3) and flash point (15-20 °C). After blending, it was observed that a 20% v/v blend of the petrochemicals enhance the physicochemical properties of major petroleum products (PMS, kerosene, diesel). It could be concluded that the use of liquid petrochemicals for the enhancement of petroleum parameters would go a long way in alleviating basic cost associated with petroleum product production.

Molecular dynamics study of waste tire pyrolysis: Focus on intermediate product evolution and sulfur migration law

With the rapid development of the automotive industry, the large number of waste tires poses significant environmental and health pressures. Pyrolysis technology offers a way to resourcefully utilize waste tires by converting them into pyrolysis oil, pyrolysis gas, and pyrolysis char, which has promising application prospects. However, there are still considerable challenges in the application of this technology, such as unclear reaction mechanisms and the high sulfur content of the products, which limit its practical implementation. Although some research has elucidated the pyrolysis mechanisms, there remain significant gaps in understanding the evolution paths of key intermediate and final products, as well as the detailed migration and transformation patterns of sulfur. This study uses reactive molecular dynamics simulation to investigate the pyrolysis process of tires. A three-dimensional polymer molecular model was constructed to study the pyrolysis process of waste tires at different temperatures, focusing on the evolution of key products, intermediate products, and sulfur-containing components. The results indicate that CH4 and ·CH3 radicals collide with unsaturated hydrocarbons through carbon-hydrogen transfer reactions and radical chain reactions, leading to polymerization. During the initial stage of pyrolysis, sulfur primarily exists in the form of sulfur-containing hydrocarbons (CHS). As pyrolysis progresses, the quantity of CHS decreases. With increasing pyrolysis temperature, the proportion of sulfur in the S form far exceeds that of CHS. At a pyrolysis temperature of 3000 K, the proportion of S is 64 %, while the proportion of CHS is 23 %.

Experimental investigation on gas-liquid–solid tri-phase product distributions during the simulated in-situ pyrolysis of tar-rich coal

The in-situ pyrolysis of tar-rich coal is a new technology for converting coal into tar and gas underground, which involves unique environmental conditions of high temperature, high pressure, large-sized coal and extremely low heating rate. Due to the different research purposes and application scenarios, the unique experimental environment of the in-situ pyrolysis is significantly different from that of conventional pyrolysis. Existing pyrolysis studies cannot be directly applied to the field of the in-situ pyrolysis of tar-rich coal, and the specialized research is indispensable. The product distribution exerts important impacts on the subsequent processing, hence an essential evaluation criterion for in-situ pyrolysis characteristics is the yield of gas-tar-char three-phase products. However, there have been few reports on the distribution of tri-phase products during in-situ pyrolysis of tar-rich coal. High temperature, high pressure, and extremely slow heating under multi-factor control were the environment of the in-situ pyrolysis which were experimentally simulated by gas pressurization in the autoclave, and the impacts of temperature, heating rate, and atmosphere at various reservoir pressures were studied. The optimal tar production temperature is 500 °C, with a yield of 12.13 %. With the increase of temperature, the aromatic hydrocarbons content in the tar product increases, the aliphatic hydrocarbons content gradually decreases and reaches 0 at 500 °C, and the phenols content first climbs and subsequently falls. There is a negative relationship between the tar yield and reservoir pressure. The impact of heating rate and atmosphere upon pyrolysis products distributions is insignificant. The present work is favorable to effective tar extraction by controlling pyrolysis parameters, and also provides better understanding for the development of large-scale tar-rich coal in-situ pyrolysis technology.

Effect of flow rate and condenser cooling water temperature on product yield of coconut trunk sawdust pyrolysis liquid smoke

Liquid smoke is a product resulting from the pyrolysis of biomass waste that contains chemical compounds with various applications, such as food preservatives, natural pesticides, and raw materials for the chemical industry. Liquid smoke is a by-product of simultaneous pyrolysis. To maximize the yield of liquid smoke while minimizing mass loss that could potentially pollute the environment, the simultaneous pyrolysisreactor needs to operate under optimal condensation conditions. This study observed two condensation parameters: the flow rate and the cooling water temperature of the condenser, using the case study of pyrolysis of biomass waste from coconut trunk sawdust. Pyrolysis was conducted at a temperature of 400°C for 2.5 hours, varying the flow rate of the cooling water in the condenser (1, 2, 2.5, 3, and 3.5 liters/minute)and the temperature of the cooling water (10°C, 20°C, 25°C, and 30°C). A multivariable nonlinear mathematical model was obtained, relating the yield of liquid smoke (y; %) to the water temperature parameter (x1) and the flow rate of the cooling water in the condenser (x2), which is expressed as y = 6.68 + 1.89x1 – 0.04x1² – 0.41x1x2 + 13.06x2 – 0.89x2². It was concluded that the optimal condensation conditions consist of a flow rate and cooling water temperature of 2 liters/minute and 20°C, respectively, yielding a maximum of 36% liquid smoke, 33% charcoal, and a minimum mass loss of 31%. Based on the coefficient values in the obtained mathematical model, it can also be concluded that the more dominant parameter affecting the yield of liquid smoke is the flow rate of the cooling water in the condenser, with a coefficient value of 13.06. An effective condensation system can enhance the conversion efficiency of pyrolysis vapour into liquid smoke and minimize potential pollution, demonstrating significant potential in processing biomass waste into valuable products, such as liquid smoke and charcoal, while being more environmentally friendly and energy-efficient.

A kinetic study of nonthermal plasma pyrolysis of methane: Insights into hydrogen and carbon material production

Nonthermal plasma-assisted methane pyrolysis has emerged as a promising approach for hydrogen production under mild conditions while simultaneously yielding valuable carbon materials. Herein, we develop a plasma chemical kinetic model to elucidate the underlying reaction mechanisms involved in methane pyrolysis to hydrogen and solid carbon within a gliding arc (GA) reactor. A zero-dimensional (0D) chemical kinetics model was developed to simulate the plasma chemistry during the GA-based methane pyrolysis process, incorporating reactions involving electrons, excited species, ions, and heavy species. The model accurately predicted methane conversion and product selectivity in agreement with the experimental data. A strong correlation between hydrogen production and methane conversion was observed, primarily driven by the reaction CH4 + H → CH3 + H2, contributing 44.2% to hydrogen formation and 37.7% to methane depletion. Electron impact collisions with hydrocarbons play a secondary role, accounting for 31.1% of H2 formation. This work provides a detailed investigation into the mechanism of solid carbon formation in GA-assisted methane pyrolysis. Most of the solid carbon originates from the electron impact dissociation of C2H2 through reactions e + C2H2 → e + C2 + H2/2H and subsequent C2 condensation. C2 radicals are highlighted as the major contributors to solid carbon formation, accounting for 95.0% of the total carbon yield, which might be due to the relatively low C–H dissociation energy in C2H2. This kinetic study offers a comprehensive understanding of the mechanisms behind H2 and solid carbon formation during GA-assisted methane pyrolysis.

Use of In-Situ ESR Measurements for Mechanistic Studies of Free Radical Non-Catalytic Thermal Reactions of Various Unconventional Oil Resources and Biomass

The exhaustion of conventional light oils necessitates the shift towards unconventional sources such as biomass, heavy oil, oil shale, and coal. Non-catalytic thermal cracking by a free radical mechanism is at the heart of the upgrading, prior to refining into valuable products. However, thermal pyrolysis is hindered by the formation of asphaltenes, precursors to coke, limiting cracking, causing equipment fouling, and reducing product stability. Free radicals are inherently present in heavy fractions and are generated during thermal processes. This makes these reactive intermediates central to understanding these mechanisms and limiting coking. Electron spin resonance (ESR) spectroscopy facilitates such mechanistic studies. Over the past decade, there has been no review of using in-situ ESR for studying thermal processes. This work begins with a brief description of free radicals’ chain reactions during thermal reactions and the wealth of information ESR provides. We then critically review the literature that uses ESR for mechanistic studies in thermal pyrolysis of biomass, heavy oil, shales, and coal. We conclude that limited literature exist, and more investigations are necessary. The key findings from existing literature are summarized to know the current state of knowledge. We also explicitly highlight the research gaps.

Направления совершенствования сероочистки, осушки и переработки природного газа

The results of the work of the staff of the Department of “Chemical Technology of Oil and Gas Refining” of Astrakhan State Technical University in the field of separation of three-phase reservoir mixture, increasing the efficiency of desulfurization, improving the process of drying gas and the production of continuous hydrocarbons – raw materials for petrochemistry. The influence of the quality of raw materials entering processing on the formation of deposits in technological equipment has been studied. Reconstruction of the inlet and three-phase separators of high-pressure reservoir mixture separation plants by installing a vibration damper and a depulsor on the reservoir mixture supply line to the installation, as well as reconstruction of the input of raw materials into the separator of the installation. The use of the KPG-200 defoamer and the KPG-200 AV antifoamer made it possible to reduce the consumption rate of defoaming reagents several times in gas purification plants from acidic components. The influence of various impurities on the foaming of working amine solutions (mechanical impurities, coal dust, products of thermal destruction of amine, thermostable salts, corrosion inhibitors) has been determined. It was revealed that the products of thermal degradation of amine have the greatest effect at concentrations above 3% by weight. A method for reducing the content of mechanical impurities in a solution of diethanolamine in a constant magnetic field has been developed and introduced into an industrial desulfurization plant. The filtration efficiency increases 2.6 times, the foam height is halved, and the foam stability is quadrupled. At the same time, the activity of the defoamer increases by 1.7 times. The mathematical dependence of the height of the protective layer of aluminum oxide in an adsorber with zeolite on impurities of diethanolamine has been experimentally found. The effectiveness of the developed improved distribution ring device is shown, the use of which makes it possible to practically eliminate dead zones in the zeolite layer and thereby increase the efficiency of the adsorption process and increase the inter-regeneration period on the drying unit. Studies of the catalytic pyrolysis of the butane fraction using CVM-type pentasils modified with the introduction of chromium can reduce the process temperature compared with the thermal decomposition of raw materials by more than one hundred degrees 100 °C.

Kinetics study of pyrolysis of petroleum sludge and characterization of char

Thermochemical conversion (or pyrolysis) has emerged as an effective technique for the disposal of sludge generated in process industries. This paper reports physicochemical characterization and kinetic analysis of pyrolysis of sludge from a petroleum refinery and characterization of resultant char. The sludge had high volatile matter (>70 wt%) and low ash content (15 wt%). Pyrolysis of sludge was studied using a thermo-gravimetric analyzer (TGA). The TGA data was analyzed using two isoconversional models, viz. KAS and Vyazovkin AIC are used for the deduction of kinetic triplets, viz. activation energy, pre-exponential factor, and reaction mechanism. The activation energy (Ea ) of sludge pyrolysis varied in the 64.79–190.37 kJ/mol range. The pre-exponential factor varied from 1.18E + 07 to 4.29E + 12 s−1. The predominant solid-state mechanism of thermal conversion was an order-based reaction (F2/F3). The thermodynamic factors (viz. ΔH, ΔS, ΔG) of sludge pyrolysis were also determined. Relatively small values of (Ea – ΔH) ∼ 5 kJ/mol revealed high susceptibility of sludge for thermal conversion. Residual char after pyrolysis was characterized for physicochemical properties. The char properties were fixed carbon = 54.37%, calorific value = 22.48 MJ/kg, and BET surface area = 18.35 m2/g. These properties make char suitable for numerous applications.

Intrinsic Metal Component-Assisted Microwave Pyrolysis and Kinetic Study of Waste Printed Circuit Boards

Waste printed circuit boards (WPCBs) hold great recycling value, but improper recycling can lead to environmental issues. This study combines pyrolysis and microwave technologies, leveraging the unique phenomenon where metal materials tend to “spark” in a microwave field, to develop a microwave pyrolysis process for WPCBs that incorporates metal fillers. The research analyzes the effects of microwave power, metal filler addition, and pyrolysis time on the efficiency of microwave pyrolysis. It explores the mechanisms of microwave pyrolysis and the pathways of pyrolysis product formation, and the kinetics of the pyrolysis reaction of WPCBs. The results indicate that microwave-assisted pyrolysis greatly improves efficiency. Within the experimental range, the optimal conditions are found to be a microwave power of 1600–1800 W, a metal filler addition of 10%, and a pyrolysis time of 10 min. Under these conditions, the yield of pyrolysis liquid was 12.8%, with approximately 5–12 different components, while the yield of pyrolysis gas was 12.7–13.4%, with about 9–11 different components. Compared to conventional pyrolysis products, the liquid products from microwave pyrolysis are simpler and more advantageous for resource utilization. Theoretical calculations show that the average activation energy for the microwave pyrolysis process is 81.05 kJ/mol, with an average reaction order of 0.93, which is greatly better than the 147.75 kJ/mol of the conventional pyrolysis process.

Comparative study of grass pyrolysis over regenerated catalysts: Tyre ash, zeolite, and nickel-supported ash and zeolite

This paper presents investigations on catalytic and non-catalytic grass pyrolysis conducted at 500 °C using two reactor scales: a micro-scale reactor and a laboratory fixed-bed reactor. Four catalysts were employed in the catalytic pyrolysis process: car tyre ash, commercial zeolite mordenite-sodium, nickel supported on ash, and nickel supported on zeolite. The use of catalysts reduced the production of oxygenates and promoted the formation of gaseous compounds, with the most pronounced effect observed for nickel supported on zeolite. Catalytic pyrolysis produced chars with yields that were higher than those of the non-catalytic process. The coking behaviour of the spent catalysts was evaluated by analysing carbon content, with the highest content (3 wt% C) obtained for ash after the first cycle. In the second cycle, the deposited carbon content decreased for all catalysts. Furthermore, the employment of catalysts was shown to promote the production of hydrogen, methane, and other hydrocarbons in pyrolysis gas. The higher heating value of the pyrolysis gas was the highest at 21.1 MJ/m³ when the ash catalyst was first used for pyrolysis. Reusing the pyrolysis catalysts slightly reduced the heating value of the gas to 20.3 MJ/m³ over ash and 20.6 MJ/m³ over zeolite.

Catalytic pyrolysis mechanism of waste R134a/R32 refrigerant mixture over Cu(1 1 1) surface: Density functional theory study

The development of degradation treatment technology for waste hydrofluorocarbons (HFCs) was urgent. Copper, a commonly used catalyst, can be used to efficiently catalyze the pyrolysis of pure HFCs, but the catalytic pyrolysis study of HFC mixtures was lacking. In this work, the catalytic pyrolysis of R134a/R32 refrigerant mixture over Cu(1 1 1) surface was studied by using density functional theory method. Four initial catalytic pyrolysis reactions of R134a in adsorbed R134a/R32 mixture and adsorbed R134a, two initial catalytic pyrolysis reactions of R32 in adsorbed R134a/R32 mixture and adsorbed R32 were investigated. The results showed that copper had a better catalytic effect on the pyrolysis of adsorbed R134a/R32 mixture, adsorbed R134a and adsorbed R32. On the Cu(1 1 1) surface, the pyrolysis of R134a was inhibited and the pyrolysis of R32 was improved by the mixture of R134a and R32.

Feasibility study of plasma pyrolysis on dairy waste

Considering the ever-increasing necessity of the disposal of industrial and household waste and using mechanisms through which the utmost potential of the waste is directed to the efficient recycling of materials or forms of energy, the current study aims to investigate plasma pyrolysis as an eco-friendly and appropriate approach that leads to the production of value-added products. The novelty of this study lies in its development of a method for spoiled milk disposal since no efficient solution has been provided yet in this respect. The other benefit of implementing the proposed disposal method is the production of high-quality syngas. The maximum produced hydrogen percentage and syngas rate during the process under study in this research were obtained as 60.396 % and 2.166, respectively. A plasma method is a rare approach to yielding products with such values. The obtained results revealed that the transferred thermal plasma could efficiently dispose of the spoiled milk waste and be used as a novel approach to the green synthesis of hydrogen through plasma pyrolysis.

Influence of polypropylene and high-density polyethylene on isothermal pyrolytic degradation of discarded bakelite: Kinetic analysis and batch pyrolysis studies

The recycling of thermosetting plastics such as discarded bakelite poses greater challenges than thermoplastic polymers like polypropylene (PP) and high-density polyethylene (HDPE), particularly through pyrolysis requiring specialized reactors. This study examines the isothermal thermal degradation kinetics and batch pyrolysis behaviors of bakelite, along with its blends with PP and HDPE, emphasizing the characterization of pyrolytic oils for designing optimized reactors. For the study on isothermal thermal degradation kinetics, isothermal thermogravimetric analysis was performed at specified temperatures (300, 350, 400, 450, and 500°C), chosen based on the predominant non-isothermal degradation behavior of bakelite. The batch pyrolysis of discarded bakelite and blended bakelite with PP/HDPE is carried out at 450°C. The chemical composition analysis of pyrolytic oils is performed using Fourier transform infrared (FTIR) spectroscopy, with comprehensive compound analysis conducted using Gas Chromatography-Mass Spectrometry (GCMS). Isothermal thermogravimetry at temperatures ranging from 300°C to 500°C reveals increased thermal degradation with rising pyrolytic temperatures, reaching maximum weight losses of 55 % for bakelite, 82.74 % for PP-bakelite blends, and 90.8 % for HDPE-bakelite blends at 500°C. The isothermal kinetics study reveals that bakelite degrades via D1-diffusion, polypropylene-blended bakelite via A2-Avrami-Erofeyev, and high-density polyethylene-blended bakelite via A3-Avrami-Erofeyev, with activation energies of 17.178, 7.193, and 3.550 kJ/mol, and Arrhenius constants of 0.095, 0.042, and 0.017 min.−1, respectively. The highest condensable yield of 58.76 % during PP-blended bakelite co-pyrolysis underscores its potential for resource recovery. FTIR and GC-MS confirm the presence of alkanes, cycloalkanes, alkenes, cycloalkenes, aromatic hydrocarbons, and oxygenated compounds in the pyrolytic oils, providing detailed insights into their chemical composition. These findings offer critical insights into the thermal degradation behavior and kinetics of bakelite and polypropylene/high-density polyethylene-blended bakelite, highlighting opportunities for efficient waste plastic utilization through pyrolysis for resource recovery and energy generation, and providing essential knowledge for designing isothermal pyrolysis reactors.

Isothermal pyrolysis of discarded bakelite: Kinetics analysis and batch pyrolysis studies

Plastic is widely used, leading to an increase in plastic waste in the environment and resulting in pollution. Plastic waste can currently be managed differently and reduced by converting it into useful products via different methods. The extensive use of thermosetting polymers such as bakelite, which are nonrecyclable, has led to an increase in bakelite scrap and pollution. Therefore, minimizing pollution due to such waste requires sustainable, modern, eco-friendly, and economical recycling technology and the upgrading of existing recycling technology. This work reports the recycling of discarded bakelite through pyrolysis and a kinetic study of the isothermal pyrolysis of bakelite via model fitting methods as well as product analyses. Therefore, isothermal degradation experiments for discarded bakelite were carried out at different temperatures (300, 350, 400, 450, and 500 °C) for 2 h. The isothermal degradation of bakelite follows the D1-diffusion model fitting method, with an activation energy (Ea) of 17.178 kJ/mol and an Arrhenius constant (A) of 0.095 min−1. The kinetic information provided throughout the research will aid in the development of an appropriate reactor for the valorization of discarded bakelite. Batch pyrolysis of bakelite gives the highest yield of 39.12% pyrolytic waxy oil at 450 °C. The presence of components such as alkanes, cycloalkenes, alkenes, alcohols, ethers, and aromatic compounds in the pyrolytic waxy oil and residue was confirmed by FTIR and GC‒MS analysis.

Thermal conversion studies of lignin pyrolysis and the catalytic effect of fe: A reactive molecular dynamics study

Lignin is one of the important components of biomass, and its pyrolysis process has been widely studied. The advantages of iron-based catalysts are their low cost, low environmental pollution, and the ability to extract and reuse from the system. However, research on the effect of metallic iron on lignin pyrolysis is limited. This study revealed the influence of iron on lignin pyrolysis process at the microscopic level through reactive molecular dynamics (ReaxFF MD) simulation, while considering the influence of different temperatures. It was found that increasing the temperature can increase the production of H2 and CO gases and improve the efficiency of lignin decomposition. In addition, the addition of catalyst iron can accelerate the decomposition of the benzene ring, making the lignin pyrolysis process deeper and more thorough, while increasing the production of H2 and CO. The activation energy of the system was calculated and it was found that the addition of catalyst iron can significantly reduce the activation energy of lignin pyrolysis, proving the excellent catalytic effect of the catalyst. The catalytic pyrolysis strategy provided in this study, using iron as a catalyst to catalyze the pyrolysis process of lignin, can effectively utilize biomass resources in industrial production.