Pyrolysis Gas Research Articles

Prediction of Chemical Composition of Gas Combustion Products from Thermal Waste Conversion

The current global energy crisis is driving the need to search for alternative raw materials and fuels that will be able to ensure the continuity of strategic industries, such as the steel industry. A chance to reduce the consumption of traditional fuels (e.g., natural gas) is to utilise the potential of gases from the thermal conversion of waste, and, in particular, pyrolysis gas. Unfortunately, despite its high calorific value, this gas is not always suitable for direct, energy-related use. The limitation is the type of waste subjected to pyrolysis, particularly plastics, rubber and textiles. Due to the above, this article proposes the co-combustion of pyrolysis gas in a ratio of 1:10 with natural gas in a pusher reheating furnace employed to heat the charge before forming. The chemical composition of flue gases generated during the combustion of natural gas alone and co-combustion with pyrolysis gas from various wastes was modelled, namely, two types of refuse-derived fuel (RDF) waste, a mixture of pine chips with polypropylene and a mixture of alder chips with polypropylene. The calculations were performed using Ansys Chemkin-Pro software (ver. 2021 R1). The performed computer simulations showed that the addition of pyrolysis gas for most of the analysed variants did not significantly affect the chemical composition of the flue gases. For the gases from the pyrolysis of biomass waste with the addition of polypropylene (PP), higher concentrations of CO and H2 and unburned hydrocarbons were observed than for the other mixtures. The reason for the observed differences was explained by conducting a formation path analysis and a sensitivity analysis for the selected combustion products.

Economic benefits for the metallurgical industry from co-combusting pyrolysis gas from waste

Economic benefits for the metallurgical industry from co-combusting pyrolysis gas from waste

Reservoir Characteristics of Ha'py-2 well in Ha'py Gas Field, Eastern Mediterranean Region, Egypt

Reservoir Characteristics of Ha'py-2 well in Ha'py Gas Field, Eastern Mediterranean Region, Egypt

Investigation in the pyrolysis of polyester coated on aluminum-based beverage: Thermodynamic properties, product and mechanism

Aluminum cans are typical solid waste. Polyester coatings not only polluted the environment, but also affected the quality of aluminum recycling. In this study, three common local polyester coatings on the surface of aluminum cans were selected as raw materials (PC-PB, PC-VY and PC-SG). Thermogravimetric analysis, elemental analysis, Fourier transform infrared spectrometer and pyrolysis gas chromatography/mass spectrometry (PY-GC/MS) were used to study the pyrolysis behavior and pyrolysis products of the polymer components coated on the aluminum cans. TG analysis showed that pyrolysis of the coatings mainly occurred at 250–540 °C, with a weight loss of about 25 % for the polyester coating PC-PB and PC-VG, and a lower weight loss of 15 % for polyester coating PC-SY. The effect of pyrolysis temperature on the pyrolysis products of polyester coatings was investigated using PY-GC/MS. The results showed that the main products of pyrolysis included four major groups: oxygenated compounds, aromatic compounds, nitrogenous compounds and aliphatic hydrocarbons. At 600 °C, the aromatic compounds, oxide-containing reached 57–67 % and 20–27 %, respectively. The main pyrolysis products include neopentyl glycol, phthalic anhydride, toluene, styrene and so on. The high content of aromatic compounds in the product can be used as chemical raw materials as well as alternative fuels. In addition, the pyrolysis principles of the three main components of polyester coatings (polyester resins, amino resins, and styrene-acrylic resins) were postulated.

Seasonal Harvesting Impact on Biomass Fuel Properties and Pyrolysis‐Derived Bio‐Oil Organic Phase Composition

ABSTRACTThermochemical conversion of giant reed biomass during periodic variations has been carried out in a semi‐batch tubular reactor at 550°C. This study was carried out after the incineration of giant reed along the river banks. Four periodic variations, late spring (HS‐4), late summer (HS‐1), late autumn (HS‐2), and late winter (HS‐3) were considered to investigate the effect of harvest time on biomass fuel properties, pyrolysis product distribution, non‐condensable gas characterization, and bio‐oil organic phase (BOP) fuel properties. The considered biomasses herein had average calorific values of 18.86 ± 0.05, 19.73 ± 0.05, 19.23 ± 0.04, and 18.44 ± 0.04 MJ/kg during HS‐1, HS‐2, HS‐3, and HS‐4, respectively. The biomass, bio‐oil organic phase, biochar, and pyrolysis gas were characterized using thermogravimetric analysis (TGA), gas chromatography–mass spectroscopy (GCMS), Fourier transform infrared spectroscopy (FTIR), micro‐GC, and scanning electron microscopy (SEM/EDS). The organic phase of bio‐oil was isolated using a 125 mL separating funnel, allowing natural stratification of the immiscible phases. BOP yield increased from 5 to 11 wt% during HS‐4 and HS‐3, respectively. Higher heating values (HHV) of the BOP ranged from 19.4 ± 0.03 to 22.6 ± 0.02 MJ/kg in relation to the active growth stage and senescence‐dormant phase. Physical and chemical properties (TAN, density, viscosity, water content, and CHNS) and chemical compound groups of organic phase bio‐oil were analyzed. The produced BOP was rich in phenolics for all considered periods. The effect of harvest time showed that biomass and bio‐oil organic phase fuel properties are improved during the senescence‐dormant period. As a result, giant reed biomass should be harvested during autumn to avoid incineration that releases carbon dioxide into the atmosphere and will also reduce the occurrence of artificial flooding.

Microplastics in stools and their influencing factors among young adults from three cities in China: A multicenter cross-sectional study

The mass concentration of microplastics in stools and influencing factors remain unclear. The aim was to investigate the types and mass concentrations of microplastics in the stools of young college students and to explore potential influencing factors. Twenty-six participants were recruited from colleges in each city using stratified simple sampling, including Changsha, Shanghai, and Changchun. Participants’ dietary and fluid intake behavior was recorded using the 3-day 24-h dietary questionnaire and the 7-day 24-h fluid intake record, respectively. Lifestyle factor information related to microplastic exposure was collected through a microplastic exposure questionnaire. Stools were collected and detected using pyrolysis gas chromatography–mass spectrometry (Py-GCMS) method. Eventually, 78 participants completed the study. The detection rate of microplastics, including polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), polypropylene (PP) and polyethylene terephthalate (PET), in stools was 98.7%, with a total mass concentration of 54.7 (10.1–102.7) μg/g. There were differences in the total mass concentrations of microplastics in the stools of participants in three cities, namely Changsha, Shanghai, and Changchun, which decreased sequentially (χ2 = 47.819, P < 0.05). Participants with a relatively high frequency of takeaway food consumption had higher total mass concentrations of microplastics mass concentrations in stools (χ2 = 7.390, P < 0.05). Participants with a relatively high frequency of consuming reheated food had a greater mass concentration of PET microplastics (χ2 = 6.117, P < 0.05). The total mass concentration of microplastics, as well as the mass concentrations of PE, PVC, PP, and PA66, in the bottled water intake group were greater than those in the nonintake group (all P < 0.05). Overall, the total mass concentration of microplastics in stools was related to residential city, consumption of reheated food, and bottled water intake (all P < 0.05). Young college students generally experience microplastic exposure, with the main types being PE, PVC, PS, PP, PET, and PA66. Living location, reheated food consumption, and bottled water intake were factors influencing microplastic exposure.

Pyrolysis and oxidation characteristics and energy self-sustaining process design of retired wind turbine blades

Pyrolysis offers a straightforward method to extract valuable glass fiber from retired wind turbine blades, showing great potential for resource utilization. Experimental findings reveal that calorific value of pyrolysis gas increases with pyrolysis temperatures between 400 and 700 ℃. When the solid product obtained was oxidized at 500 ℃ for 40 minutes, clean glass fiber products can be obtained. Based on it, a new pyrolysis process for retired wind turbine blades and clean glass fiber recovery was designed using Aspen Plus software. By comparing the influence of pyrolysis temperatures, the stability and flexibility of the system were analyzed. The simulation results indicate that the pyrolysis temperature within the range of 400–700 ℃ can fully achieve energy self-sufficiency of the system, and excess heat can be stored by heating molten salts with high heat capacity. In practical applications, it is recommended to set the pyrolysis temperature and oxidation temperature at approximately 500 ℃, thereby further improving the economic efficiency of the system. This pyrolysis and recovery process can significantly improve its economic efficiency through energy self-sustaining system optimization, marking a significant contribution to the sustainable and economic management of retired wind turbine blade resources.

Microplastics in Urban Ambient Air: A Rapid Review of Active Sampling and Analytical Methods for Human Risk Assessment

This study conducted a rapid review to evaluate active air sampling and analytical methods for characterizing outdoor air microplastics in urban areas. We synthesized information from 35 peer-reviewed journal articles. Studies utilizing active sampling methods were able to provide detailed data on inhalation concentrations and doses. The analytical techniques reviewed were categorized into microscopy, Fourier Transform Infrared (FTIR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), and mass spectrometry, including pyrolysis–gas chromatography (Py-GC). While conventional FTIR and Raman spectroscopy can identify microplastics in total suspended particles, advanced instruments such as µRaman and SEM are crucial for analyzing inhalable microplastics (e.g., particles smaller than 10 µm). Characterizing the shapes and colours of microplastics can provide qualitative estimates of their sources, with fibres and the colour black being the most predominant characteristics. Establishing dose–response relationships for health effects requires quantitative analyses; thus, combining techniques like µRaman with Py-GC is essential for comprehensive human risk assessments. Future studies should focus on identifying and quantifying inhalable microplastic compounds that are relevant to human health.

Acute study and the absorption, distribution, and metabolomic profile of the natural compound propyl-propane-thiosulfonate from allium in rats

Propyl-propane thiosulfonate (PTSO) is an organosulfur compound found in Allium spp., commonly used in animal nutrition and various agri-food applications. Extensive studies have demonstrated the safety of PTSO for feed use, including investigations into genotoxicity, mutagenicity, and subchronic toxicity in rats. However no kinetic or metabolic study has been previously performed. This study aimed to conduct an in vivo toxicokinetic assessment of PTSO in rats. For this purpose, eighteen Sprague Dawley rats received an oral dose of 175 mg/kg via gastric gavage. Plasma and tissue samples (brain, stomach, liver, lung, kidney, spleen, and testicle) were collected at specific intervals (10 min, 20 min, 30 min, 1h, 2h, 4h, 6h, 8h, and 24h) and analyzed using Gas Chromatography-High-Resolution Mass Spectrometry, Pyrolysis Gas Chromatography -High-Resolution Mass Spectrometry, and Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry to detect PTSO and its metabolites. PTSO was not detected in plasma or solid tissues throughout the sampling period; however, phase I and phase II metabolites were identified in both matrices. The toxicokinetic profile of s-propyl mercaptocysteine (CSSP), a significant metabolite, exhibited a well-correlated model. In the stomach, CSSP reached peak concentrations of 495.63 ± 6.53 ng/mL, while lower concentrations of 123.59 ± 8.35 ng/mL were observed in plasma. Furthermore, CSSP demonstrated high water solubility and rapid excretion, with a plasma half-life of 0.66 ± 0.05 h. Overall, these findings substantiate the safety profile of PTSO for specific agri-food applications under the conditions investigated.

Turning Trash to Treasure: The Influence of Carbon Waste Source on the Photothermal Behaviour of Plasmonic Titanium Carbide Interfaces.

Pyrolysis of carbonaceous waste material has become an attractive method of recycling to generate value added products. Alongside pyrolytic oil and gas fractions, the thermal degradation forms solid pyrolytic char, which can be further processed. Local waste materials, including birch wood residue (BW), Reynoutria japonica stems (KW), spent coffee grounds (CG), tire rubber (TR), and lobster shells (LS) we assessed to form pyrolytic char. Using a simple acid treatment step on the chars, this study has shown successfully incorporate many of them into the low-temperature synthesis of plasmonic TiC NPs. Each char was shown to display distinctive physical and chemical characteristics, which was exploited to synthesize TiC NPs with unique properties. To study the plasmonic behaviour of each TiC sample, solar driven desalination experiments were conducted. TiC formed from TR char achieved broadband absorbance of ~95 % of the solar spectrum, reaching a near-perfect solar-to-vapor generation efficiency of 95 %, or a water generation rate of 1.40±0.01 kg m-2 h-1 under one-sun illumination. This makes it the best performing of all chars tested, and among the top performers reported in the literature to date. The evaporators maintain activity over time and under strongly hypersaline conditions.

The Gas Generation Process and Modeling of the Source Rock from the Yacheng Formation in the Yanan Depression, South China Sea

The research on deepwater oil and gas exploration areas is relatively limited, and sample collection is difficult. A drilled coal sample from Yanan Depression was used to investigate the hydrocarbon generation process, and the potential, by a gold tube thermal simulation experiment. The results show that the total gas yield was much higher than the oil yield. According to an analysis of the gas pyrolysis data, as represented by ln(C1/C2) and ln(C2/C3), the gas generation process consisted of two forms, namely, primary gas with ~1.33% Ro and secondary gas that occurred at levels greater than 1.33% Ro. The primary gas from kerogen was generated at ~1.33% Ro, which coincided with the %Ro value of the maximum oil yield. The activation energy distribution of the C1–C5 generation processes ranged from 54 to 72 kcal/mol, with a frequency factor of 6.686 × 1014 s−1 for the coal sample. We constructed the history of gas generation on the basis of the process and kinetic parameters, combined with data on the sedimentary burial and thermal history. The extrapolation of the gas history revealed that the gas has been generated from 5 Ma to the present, with a maximum yield of 178.5 mg/gTOC. This history suggests that the coal has good primary gas generation potential and provides favorable gas source conditions for the formation of gas fields. This study provides a favorable basis for expanding the effective source rock areas.

Exploring the pyrolysis process of simulated oily sludge: Kinetics, mechanism, product distribution, and S/N elements migration

Pyrolysis is an important method for energy recovery and harmless treatment of oily sludge, definite reaction mechanism and the transformation of S and N elements is a key to improve the pyrolysis products. In this paper, a simulated oil sludge (SOS) was pyrolyzed at various temperatures of 400–700 °C in a tube furnace focusing on pyrolysis process, kinetic parameters, reaction mechanisms, S and N element migration patterns and product distributions. Kinetic parameters were deducted by FWO, KAS, Friedman and Starink methods, and the activation energy were 186.23–231.20 kJ/mol (Avg. 210.71 kJ/mol), 190.18–233.80 kJ/mol (Avg. 212.02 kJ/mol), 196.93–242.01 kJ/mol (Avg. 209.88 kJ/mol) and 184.82–230.95 kJ/mol (Avg. 218.67 kJ/mol), respectively, showed high similarity. All the pre-exponential factors were higher than 109 s−1, which indicated high reactivity of SOS during pyrolysis, and the pyrolysis process followed the nucleation growth model (A3). Pyrolysis temperatures had a significant influence on products distribution. The maximum yields of pyrolysis tar and gas were observed at 550 °C and 700 °C, respectively. Pyrolysis tar was dominated by aromatics and acids, while pyrolysis gas was mainly composed of H2 and CH4. Additionally, high temperatures could facilitate the transfer of more S and N into tar or gas products, and S and N compounds were mainly thiophene-S, sulfoxide-S, pyridine-N and pyrrole-N in char and CS2, CH3SH, COS, SO2, H2S, NH3, HCN and NOx in gas.

CO2-free production of hydrogen via pyrolysis of natural gas: influence of non-methane hydrocarbons on product composition, methane conversion, hydrogen yield, and carbon capture

Methane pyrolysis represents a CO2-free hydrogen production route that enables simultaneous carbon capture. While the majority of previous studies in the field focus on pure CH4 as feed gas stream, commercial processes will typically rely on natural gas as feedstock that contains also non-methane hydrocarbons such as ethane, propane, and n-butane. Therefore, the present study evaluates how CH4 conversion, H2 selectivity, product composition, and solid carbon yield evolve when using either pure CH4 or synthetic natural gas (SNG) as feed gas stream for a thermal pyrolysis process in a lab-scale high-temperature reactor. For this, industrially viable conditions are applied, namely temperatures between 1000 °C and 1600 °C, residence times between 1 s and 7 s, and molar H2 dilution ratios between 1:1 and 4:1. Although the use of SNG results in slightly lower hydrocarbon conversions because the additional components in SNG result in a higher effective H2 dilution ratio compared to a CH4-only feed, the non-methane hydrocarbons in the SNG have a positive effect on both H2 selectivity and solid carbon yield. Taking existing mechanistic understanding into account, these positive effects are attributed to radicals formed from the non-methane hydrocarbons, which facilitate dehydrogenation steps from ethane to ethylene and hereby increase the relative amount of H2 originating from CH4. The introduction of a carbonaceous fixed bed further benefits the performance of the pyrolysis process and ultimately enables to capture more than 98% of carbon in its solid form under industrially viable process conditions.

Investigation of Peat Pyrolysis Products by Pyrolytic Gas Chromatography

Investigation of Peat Pyrolysis Products by Pyrolytic Gas Chromatography

Study on pyrolysis process and mechanism of organic coating of waste polyesterimide enameled wire based on density functional theory

The pyrolysis treatment of waste polyesterimide enameled wire offers significant advantages such as continuous processing, non-hazardous nature, and high resource recovery rate. However, research on its pyrolysis process and mechanism remains insufficiently explored. In this study, techniques including thermogravimetry (TG), Fourier transform infrared spectroscopy(FT-IR), pyrolysis–gas chromatography-mass spectrometry(Py-GC/MS) were employed to investigate pyrolysis temperature, weight loss rate, pyrolysis and kinetic parameters, composition and distribution of pyrolysis products, and changes in functional groups under different temperatures and heating rates. The pyrolysis of polyesterimide enameled wire can be divided into three stages: volatilization of specific components (314.8 °C,1.6 %), rapid decomposition of polyesterimide (435.2 °C, 44.7 %), and generation of small organic molecules with the fixation of pyrolytic carbon (750 °C, 9.0 %). The main components of the pyrolysis gas products include aromatic compounds, ethers, aromatics, ketones, and carbon dioxide. At 400 °C, a substantial amount of pyrolysis gas products and free radicals are produced, with an increase in aromatic hydrocarbons. The carbon distribution in the pyrolysis products mainly focuses on C6-C10 and C11-C15, and many organic compounds such as benzoic acid, phenol, and aniline are generated. Based on density functional theory, the bond dissociation energies in the polyesterimide were calculated. This clarified the possible thermal decomposition pathways of the polyesterimide and provided the energy barrier values, elucidating the generation mechanism of pyrolysis products during thermal decomposition. The copper atom in specific location reduces the negative ESP of O and increases the positive ESP of H in EPI, which makes H more likely to attach to O. The presence of Cu increases the ESP range and promote the pyrolysis process. This study provides a theoretical basis for the high-value recycling of waste polyesterimide enamelled wire.

Distribution of volatile composition from co-pyrolysis of NMH coal and dealkaline lignin

Experimental studies on co-pyrolysis of coal and lignin are carried out on a fixed-bed reactor to investigate composition and transformation of the co-pyrolysis products. The results show that co-pyrolysis reduces yield of char and promotes yield of gas, the maximum pyrolysis gas yield increases by 33.1%. Co-pyrolysis has a significant promotion effect on generation of CH4 and CO. The interaction between the pyrolyzed volatile fractions of coal and lignin shows the most pronounced interaction at a coal to lignin mixing ratio of 1:1, and the pyrolysis tar yield shows a positive synergistic effect. Guaiacols are converted to monophenols and bisphenols during the co-pyrolysis process. Content of monophenols and bisphenols increase by 2.9% and 9.8%, respectively, while content of guaiacols decreases by 5.1% compared with the theoretically calculated values. The breakage of carbonyl and carboxyl groups, and the interaction with volatile components are enhanced, which inhibits formation of ethers, aldehydes and acids, and promotes generation of phenols, release of oxygenated gases and stabilization of pyrolysis tar. The introduction of lignin into coal pyrolysis also significantly promotes the upgrading of tar in which light components is nearly 90%.

Production of MAH-Rich bio-oil from co-pyrolysis of biomass and plastics using carbonized MOF catalysts under microwave irradiation

This study investigates the effects of various carbonized MOF catalysts on the properties of products derived from microwave-assisted co-pyrolysis of biomass and plastics. The Cr@C catalysts were prepared from MIL-101(Cr) precursors at different microwave carbonization temperatures, while Fe/Cr@C catalysts were synthesized under varying Fe loadings. Characterization of the catalysts was performed using XRD, BET, and FT-IR. The distribution of solid, liquid, and gaseous products, as well as the composition of bio-oil and syngas, were analyzed. The results show that the 5Fe/Cr@C catalyst achieved the highest pyrolysis gas yield (33.05 wt%), while the 15Fe/Cr@C catalyst produced the highest hydrogen yield (24.97 vol%). The Cr@C catalyst promoted hydrocarbon production, with Cr@C-700 achieving a total hydrocarbon content of 51.04%. The incorporation of Fe enhanced the selectivity of Cr@C catalysts for monocyclic aromatic hydrocarbons(MAHs) in the bio-oil. The aromatic content reached a maximum of 19.88% with the 15Fe/Cr@C catalyst. Notably, the MAHs content in the 5Fe/Cr@C catalyst accounted for 97.1% of the total aromatic hydrocarbons. This research provides valuable insights into the potential of carbonized MOF catalysts for producing bio-oil rich in single-ring aromatic hydrocarbons from microwave-assisted co-pyrolysis of biomass and plastics.

Mechanism of selective texturing of CFRP by femtosecond laser

Carbon fiber-reinforced polymer (CFRP) has become an indispensable key material in the aerospace field due to its advantages of lightweight and high strength. In this study, a new process of selective texturing by femtosecond laser is proposed to improve the surface performance of CFRP without destroying fiber continuity. To explore the process mechanism of selective texturing of CFRP, the concept of the removal threshold is proposed, the influence of laser scanning direction and laser energy on the groove and the HAZ is studied. Furthermore, the optimization strategy of processing parameters during selective texturing is given. It is found that the scanning direction influences the transfer path of the heat significantly and therefore affects the groove geometry. As the scanning angle increases, the ablation threshold of resin rises gradually, while the ablation threshold of carbon fiber experiences a rapid increase before 30° and a gentle increase thereafter. Additionally, the groove shows a steady growth in width and undergoes a stepped decrease in depth, and the width of the HAZ increases. As laser energy increases, the width of the groove and HAZ increases, and the depth of the groove increases in a step pattern. The selective texturing mechanism of surface resin involves the coupling superposition of multiple effects, including photolysis resulting from multi-photon absorption, pyrolysis caused by direct laser energy absorption, thermal effects due to heat transfer of fiber, thermal effects of pyrolysis gas, and mechanical denudation. The laser energy density of 12-13J/cm2 is the optimal parameter range for achieving selective texturing.

Catalytic Aromatization of Rapid Pyrolysis Gas of Low-density Polyethylene Using a Tandem Reactor

Catalytic Aromatization of Rapid Pyrolysis Gas of Low-density Polyethylene Using a Tandem Reactor

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 %.