Rapid Pyrolysis Research Articles

Powder activated coke prepared from coal fast pyrolysis: fractal characteristics and SO2 adsorption

The rapid and low-cost preparation of powder activated coke (PAC) is very important for the promotion of fluidized dry desulfurization technology of activated coke. In order to explore the effect of rapid pyrolysis process on SO2 adsorption capacity of PAC, the fractal analysis of PAC prepared under different atmospheres was carried out. The Frenkel-Halsey-Hill (FHH) method was used to determine two fractal dimensions D1 and D2, under relative pressures of 0-0.5 and 0.5-1, respectively. The results indicate that the fractal dimensions were influenced by the concentrations of activation agents with D1 ranging from 2.1838 to 2.8643 and D2 ranging from 2.7485 to 2.9257. The effect of steam on the fractal dimension of PAC sample is small, but oxygen has a great promotion effect on the fractal dimension. An n-shaped curve-based relationship between fractal dimensions and coke yields is observed with a peak values of fractal dimensions appearing around 64% yield. The SO2 adsorption capacity shows a consecutively positive linear correlation with D2, while it illustrates distinctly different linear rates with D1 in intervals of 2-2.6 and 2.6-3, respectively. Taking advantage of fractal analysis as research method, this paper clarified the influence of activation atmosphere and ablative degree on the SO2 adsorption capacity of PAC, and the research conclusion provided a basis for the PAC preparation with high SO2 capacity.

АКТУАЛЬНІСТЬ ВИКОРИСТАННЯ МІСКАНТУСУ ЯК БІОМАСИ ДЛЯ СПАЛЮВАННЯ В ТВЕРДОПАЛИВНИХ КОТЛАХ

The purpose of the research is to evaluate the relevance of using miscanthus energy culture as biomass for burning in solid fuel boilers. Research methods. Analytical studies on the relevance of the use of energy culture of miscanthus as biomass for burning in solid fuel boilers were carried out by processing the available scientific and informational reports. Research results. For the production of biomass, special energy crops are used, which are characterized by rapid growth of technological mass - willow, poplar, sycamore, or certain varieties of herbaceous plants (miscanthus, millet, sorghum, etc.). Energy crops are plants that are specially grown for use directly as fuel or for biofuel production. After a single planting, the crop (miscanthus) can be harvested annually for 15 years or more with an average yield of 10 t/ha. Miscanthus has a well-developed root system (2,5 m deep), is characterized by rapid growth and resistance to low temperatures. Technological options for biomass combustion are divided into three main types: combustion in a layer, dust combustion, combustion in a pseudo-liquefied state, as well as a combined type - combined combustion of biomass with other fuels. Miscanthus is characterized by a fairly high level of energy production, and actually 143-560 GJ/ha, energy yield is 360 GJ/ha/year. Increasing the use of perennial energy crops such as miscanthus helps reduce fossil fuel consumption. In addition to high yields, drought resistance, maintaining soil structure, reducing the risk of soil erosion, improving soil organic matter and other important agronomic indicators, miscanthus has a high resource energy efficiency, which can be 90 %, a high level of conversion. With a yield of 8-17 t/ha/year, the selling price of miscanthus during its processing into thermal energy and biological oil of rapid pyrolysis was received at almost the same level - 100 €/t. The calorific value of energy culture is 17,7 MJ/kg, according to other scientific data is in the range of 16,0-17,2 MJ/kg, according to regulatory requirements CEN / TC 14961: 2005 – 18,4 MJ/kg, despite some deviations from the standards, miscanthus can be described as a valuable energy raw material suitable for combustion in boilers. Conclusions. According to the results of analytical studies, the relevance of using miscanthus energy culture as biomass for combustion in solid fuel boilers was assessed for the first time. Energy crops (miscanthus) after a single planting can be harvested annually for 15 years or more. Miscanthus is characterized by a high level of energy production, namely 143-560 GJ/ha, energy yield is 360 GJ/ha/year. Increasing the use of perennial energy crops such as miscanthus helps reduce fossil fuel consumption. Miscanthus has a high resource energy efficiency, which can be 75-90 %, a high level of conversion. According to scientific reports, the calorific value of energy crop (miscanthus) is 17,7 MJ/kg, according to regulatory requirements CEN / TC 14961: 2005 – 18,4 MJ/kg, despite some deviations from the standards, miscanthus is characterized as a valuable energy raw materials effective during combustion in solid fuel boilers. Key words: biomass, renewable energy sources, energy efficiency, energy crops, miscanthus, solid fuel boilers.

A Novel Rapid Pyrolysis of Non-fluorine MOD-Derived YBCO Thin Films

A Novel Rapid Pyrolysis of Non-fluorine MOD-Derived YBCO Thin Films

Determination of size and porosity of chars during combustion of biomass particles

This research focused on the size and overall porosity (pore volume) of carbonaceous chars, originating from high-heating rates and high-temperature pyrolysis and/or combustion of biomass. Emphasis was given to torrefied biomass chars. First, the porosity of char residues of single biomass particles of known mass was determined, based on an assumed value of skeletal density and by comparing experimentally observed temperature-time histories with numerical predictions of their burnout times. The average char porosities (effective porosities) of several raw and torrefied biomass particles were calculated to be in the range of 92–95%. Thereafter, these deduced porosity values were input again to the model to calculate the size of chars of other biomass particle precursors, whose initial size and mass were not known. Such biomass particles were sieve-classified to different nominal size ranges. This time, besides the porosity, representative time-temperature profiles of biomass particles in the aforementioned size ranges were also input to the model. Biomass particles are highly irregular with large aspect ratios and, in many cases, they melt and spherodize under high heating rates and elevated temperatures. Knowledge of the initial size of the chars, upon extinction of the volatile flames, is needed for modeling their heterogeneous combustion phase. For this purpose, numerical predictions were in general agreement with measurements of char size obtained from both scanning electron microscopy of captured chars and real-time high-speed, high-magnification cinematographic observations of their combustion. Results showed that the generated chars of the examined biomass types were highly porous with large cavities. The average initial dimension of the chars, upon rapid pyrolysis, was in the range of 50–60% the mid-value of the mesh size of the sieves used to size-classify their highly irregular parent biomass particles.

Carbon Dots–Based Ratiometric Fluorescence Sensor for Hippuric Acid

Herein, carbon dots–based ratiometric fluorescence sensor is developed for the first time for hippuric acid. Carbon dots, with an amorphous structure of size less than 10 nm, are synthesized by a microwave‐assisted rapid pyrolysis method from citric acid and ethylenediamine. The broader photoluminescence (PL) emissions spectrum of carbon dots (CDs) (full width at half maximum [FWHM] 135 nm) at 228 nm excitation shows sensitivity toward hippuric acid. The underlying sensing mechanism is identified as inner filler effect. The implementation of ratiometric strategy makes the sensor superior to the existing single wavelength‐dependent sensor in terms of the environmental influences on sensing. The sensor shows a limit of detection of 0.717 mg mL−1 for hippuric acid with a linear response range 0–4 mg mL−1. The selectivity test of the sensor with other urine components are also carried out and the results are presented.

Bio-fuel production from catalytic fast pyrolysis of Jatropha wastes using pyroprobe GC/MS and drop tube pyrolyzer

The effects of temperature and catalytic activity on the decomposition of Jatropha waste to bio-oil under rapid pyrolysis were investigated in this study. The pyrolytic conversion of Jatropha wastes was performed at the temperature range of 400–700 °C. The reactions were conducted and compared between two operations, an analytical pyroprobe GC/MS (µg-scale reactor) and a larger scale, drop tube pyrolyzer. Added catalysts were modified metal (Ce, Co, Ni, and Pd) over activated carbon (Ac) support. In non-catalytic trials, Jatropha wastes pyrolyzed at 600 °C yielded vapor products of mainly oxygenated compounds of acid-ester, aldehyde, and ketone. Addition of Ni/Ac and Pd/Ac catalysts resulted in significantly higher aromatic and total hydrocarbon (aliphatic and cyclic) fractions. The findings suggested that these catalysts are suitable for further investigation with a scaled-up fast pyrolysis sequential process, a drop tube reactor, to convert Jatropha waste into bio‐oil as well as various gaseous and solid byproducts depending on the operating conditions. In this case, the maximum liquid products (bio-oil) yield of 40 wt% was obtained at the reaction temperature of 600 °C and particle size of 0.125–0.425 mm with the presence of Ac. Reaction at 600 °C with Pd/Ac catalyst yielded bio-oil with the highest HHV of 29.20 MJ/kg with a pH of 6.78. Analysis of bio-oil by GC/MS revealed the main favorable products as phenols, aromatics, and hydrocarbons which increased almost two folds from base case with Ni/Ac and Pd/Ac addition. Since low oxygenated compounds, high aromatics, and hydrocarbon compounds of bio-oil are desirable, the results indicate that the bio-oil at the optimized condition can be readily applied as biofuel. Moreover, the obtained biochar as a co-product from fast pyrolysis of Jatropha wastes can be used as an alternative solid fuel.

Release characteristics of alkali and alkaline earth metals in nascent char during rapid pyrolysis

The release law of alkali and alkaline earth metals (AAEMs) during coal pyrolysis is crucial for controlling scaling, corrosion and slagging in the utilization of high AAEMs coal. To approximate entrained-flow bed gasification process, a free-falling reactor was used for coal pyrolysis to study the release characteristics of AAEMs in nascent char. Effects of pyrolysis temperature, residence time and atmosphere were investigated. The cumulative release of Na, Ca and Mg at 1100 °C was 68.0%, 47.5% and 69.8%, respectively. As pyrolysis temperature increased from 900 °C to 1100 °C, the release of Na, Ca and Mg increased by 7.0 %, 3.5% and 5.3%, respectively. The cumulative release of AAEMs increased with the pyrolysis residence time, but the release rate decreased significantly in middle and late stages. The promoted thermal decomposition of functional groups by CO2 resulted in a lower char yield. CO2 promoted Na release in early stage and Ca and Mg release in late stage. Furthermore, release of AAEMs was associated with char structure evolution in rapid pyrolysis. The presence of CO2, high temperature and prolonged residence time led to enhanced particle fragmentation, increased surface cracks, and intensified thermal decomposition of functional groups, resulting in the migration of AAEMs in carbon matrix to char surface and the release of AAEMs organically bound to carbon matrix.

The rapid pyrolysis feature and evolution of heteroatoms of Indonesian oil sand

The rapid pyrolysis behavior of a kind of Indonesian oil sand was studied by a fixed-bed reactor. According to X-ray photoelectron spectroscopy (XPS), 1H nuclear magnetic resonance spectra (1H NMR) analysis, the organic structure model of oil sand and the occurrence of heteroatoms were proposed. Liquid products were characterized by gas chromatograph with mass spectrometer (GC-MS) and atomic emission detector for gas chromatography (GC-AED). In addition, the distribution of the gaseous product was analyzed using gas chromatograph (GC). During the rapid pyrolysis process, the tar yield reached its maximum at 450 °C, and the gas yield increased rapidly with the increasing temperature, while the residual sand yield displayed the opposite trend. Aromatic esters and aliphatic hydrocarbons were the predominant components of liquid products after rapid pyrolysis treatment. More stable heteroatom compounds, such as thiophene and furan, would be released into liquid product with an elevated pyrolysis temperature. Atoms like sulphur and oxygen on the aliphatic side chain were easily transformed into gaseous products such as H2S, CO2 and CO. Sulfur-containing compounds in oil sand minerals converted from sulfate to metal sulfide during the pyrolysis process. After thermal decomposition, heteroatoms compounds in organic matter transferred to gaseous product or liquid product along with the volatiles. However, heteroatom compounds in inorganic substances presented in residual sand in a more stable form.

Gasification kinetics of Barapukurian coal char using carbon dioxide and steam reactants

Gasification of coal is a cost-effective and sustainable technology to produce syngas and hydrogen with integrated carbon capture and storage system. This study investigates the gasification characteristics of Barapukurian bituminous coal (BBC) char under carbon dioxide (CO2) and steam atmosphere using a thermogravimetric analyser (TGA). The char was prepared through a rapid pyrolysis process in a high temperature entrained flow gasifier at a temperature of 1200 °C. TGA experiments were conducted under atmospheric pressure over 700–1200 °C. Factors affecting intrinsic gasification kinetics, such as diffusion and mass transfer limitations, were optimised before conducting TGA experiments at various temperatures. Three established kinetic models of the volumetric model (VM), grain model (GM) and random pore model (RPM) fitted well with the experimental data. The activation energy determined from CO2 gasification was 1.20–1.25 times higher than that of steam gasification, indicating a higher reactivity under steam than CO2. The order of reaction using CO2 and steam was determined to be 0.67 and 0.95 at 900 °C.Graphical abstract

A general strategy for overcoming the trade-off between ultrasmall size and high loading of MOF-derived metal nanoparticles by millisecond pyrolysis

Metal-organic frameworks (MOFs) have flourished as a library of promising precursors for synthesizing carbon-supported metal catalysts by pyrolysis, but it is extremely difficult to simultaneously achieve a high metal loading and an ultrasmall size, particularly for non-noble metal (Fe, Co, Ni, etc.) that are highly active and have a strong tendency to coarsen. Here, we report a general strategy for controllable synthesize thermodynamically metastable sub-3 nm non-noble metal nanoparticles (NPs) with ultrahigh metal loading up to 41.0 wt% (12.8 at%) by rapid pyrolysis of MOF (e.g., ~ 1000 °C in 0.3 s), at least four-fold higher than the reported strategy where ultrasmall NPs were obtained but with a significant sacrifice of metal loading (usually less than 10 wt%). Furthermore, we found that the formation of metal NPs during high-temperature pulse agrees with the LaMer model (sigmoidal coarsening kinetics), in which rapid pyrolysis triggers only the initial nucleation and avoids Ostwald ripening or further coalescence. We also demonstrate the generality of our strategy in synthesizing other MOF-derived ultrasmall NPs, including non-noble metal NPs (Ni), metallic compound (CoS2), and alloy (CoPd). As a demonstration, the obtained CoPd-based catalyst showed high activity and robust stability during prolonged catalytic reactions. Therefore, our strategy and mechanistic insights enable the rational design and controlled synthesis of advanced catalysts with a good balance between ultrasmall size and a high metal loading, from more than 100,000 types of MOFs.

Feasibility study on co-processing of automobile shredder residue in coal-fired power plants via pyrolysis

Facing the challenges of organic industrial solid waste (OISW) disposal, co-processing of OISW by power plants has become a developing trend. In order to avoid feeding problems of OISW and enhance the combustion adaptability of the furnace, pyrolysis coupled with incineration technology is proposed as a potential method. Among various OISW, automobile shredder residue (ASR) is regarded as a promising fuel due to its high heating value. In view of engineering application, the researches focused on the products’ properties and economic evaluation under a wide range of heating rates which are insufficient. In this study, regarding the rapid pyrolysis by conducting the high-temperature flue gas as heating source in power plants, the pyrolysis behavior of ASR was correspondingly studied under a wide range of heating rates. The formation of volatiles and property’s improvement were further investigated for generating high-valued oil. Results showed that the high heating rate is not only beneficial to the homogenization of pyrolytic products but also the aromatization in oil and radical generation in gases. Importantly, it also contributed to the cleavage of the single bond connected to the benzene ring and carbon-oxygen single bond for esters. By conducting the enhanced cracking of volatiles, the wax-like fraction was significantly reduced. In addition, the deoxygenation in oil (oxygen content decreased by 20 wt%) and high heating value of gases (increased by 73%) were improved. Our findings demonstrated the feasibility and economic efficiency for the co-processing of ASR in coal-fired power plants via pyrolysis and thus provide guidance for future commercial application.

Investigation of the (catalytic) co-pyrolysis of Shendong coal and coal tar based on rapid pyrolysis and ANN modelling

The catalytic co-pyrolysis of coal and hydrogen-rich substances is an effective way to improve the yield and quality of coal tar. In this paper, the co-pyrolysis experiments of Shendong low rank coal (SD) and low temperature coal tar (HCT) catalyzed by hematite, chalcopyrite, nickel laterite, and molybdenite were carried out respectively. The catalytic co-pyrolysis characteristics and product distribution of coal-tar slurry with different coal-tar ratios were investigated by the thermogravimetric analyzer (TGA), pyrolysis-gas chromatography/mass spectrometer (Py-GC/MS), and fixed bed rapid pyrolysis reactor (FBR). In addition, the response surface design method and artificial neural network (ANN) were introduced to optimize catalyst ratios. The analysis results show that the experimental value of the maximum weight loss rate in the high temperature pyrolysis stage with a coal-tar ratio of 5: 5 is greater than the estimated value. Besides, the coal-tar co-pyrolysis has a synergistic effect, which strongly reduces the apparent activation energy of the pyrolysis process. The addition of HCT promotes the generation of oxygen-containing compounds and aromatics. The presence of natural minerals promotes the formation of light tar, especially mono-aromatics, aliphatics, and phenol in the pyrolysis tar. After optimizing and verifying the catalyst ratio by ANN, the pyrolysis tar yield, light component content, and light tar yield are 50.49 wt%, 46.14%, and 21.14 wt%, respectively.

Release characteristics of AAEMs and physicochemical structural evolution of char during rapid coal pyrolysis

Rapid pyrolysis experiment of Zhundong coal was conducted in a high-frequency furnace to investigate release characteristics of alkali and alkaline earth metals (AAEMs) and its correlation with changes of physical and chemical properties of char. Residence time and atmosphere during pyrolysis were important process parameters that affected the migration characteristics of AAEMs and physicochemical structural evolution of char. Experimental results show that the release of AAEMs in coal char increases over time. The maximum release rate of Na, Mg and Ca is 61.05%, 64.47%, and 44.01%, respectively. Promoting effect of CO2 on release of Na mainly occurs in the initial stage of rapid pyrolysis, nevertheless the promoting effect on release of Mg and Ca mainly is in the middle and late stage. CO2 accelerates release of AAEMs by promoting release of volatiles, facilitating decomposition of oxygen-containing functional groups and aliphatic functional groups, and promoting formation of cracks on surface of coal char.

Oxidation characteristics of soot in different entrained flow gasification processes

The morphological structure of six samples including the rapid pyrolysis soot of solid fuels (coal, biomass), the soot from non-catalytic partial oxidation(NCPOX) of natural gas in a laboratory pilot plant and an industrial plant, the commercial carbon black in natural gas furnace/coal tar furnace, were characterized by using a transmission electron microscope. Based on atmospheric thermogravimetric analyzer, the non-isothermal method (50–800 °C) was adopted to study the ignition point and the oxidation reaction rate of soot, and the oxidation reaction kinetic parameters of soot was obtained. Studies showed that the physical and chemical properties of various soot were quite different. The soot from the rapid pyrolysis of coal and biomass presented a higher sphericity and a larger particle size. The Lab-NCPOX-soot was formed at a lower temperature which caused the particle being wrapped by a carbon capsule. The Ind-NCPOX-soothad a hollow structure and a small particle size. The reactivity of the Lab-NCPOX-soot is close to that of the Ind-NCPOX-soot, which is 3.1 times that of the commercial natural gas furnace carbon black and 3.2 times that of the commercial coal tar furnace carbon black; the reactivity of NCPOX-soot is 9.0 times of the rapid pyrolysis soot of coal, and 26.6 times of the rapid pyrolysis soot of biomass. The activation energy of 2 kinds of NCPOX-soot and 2 kinds of commercial carbon blacks present staged forms with increasing temperature. The activation energy of the 2 rapid pyrolysis soot was basically unchanged with increasing the temperature.

The preparation of novel core–shell suppressor and its suppression mechanism on coal dust explosion flame

To explore ways of further guaranteeing the production safety of coal processing, novel powder suppressors with core–shell structure were prepared through anti-solvent crystallization method by loading potassium oxalate (K) and ferric citrate (T) on treated waste molecular sieve. Flame propagation experiments were performed to investigate the effects of suppressors prepared under different conditions on coal dust flame propagation. The results showed that when K and T were added simultaneously at the loading of 30 wt%, the suppressor S@T-K showed best suppression performance. The pyrolysis-oxidation mechanism of coal dust with and without suppressor S@T-K was analyzed using Coats-Redfern (C-R) method. After the suppressor was added, the activation energy increased by 11.55 kJ/mol and 15.37 kJ/mol in the rapid and slow pyrolysis stages, respectively. The activation energy values of the coal sample with and without the suppressor under different conversion ratios were further calculated using Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods. The average activation energy values during the rapid and slow pyrolysis stages both agree well with the C-R calculation, which verifies the appropriateness of using C-R method to identify the reaction mechanism. By combining the coal dust flame propagation behaviors with the pre- and post-explosion characterization results, it is proposed that waste molecular sieve composite powders with core–shell structure suppress flame propagation through the synergy of physical and chemical reactions.

Highly Dispersive Metal Atoms Anchored on Carbon Matrix Obtained by Direct Rapid Pyrolysis of Metal Complexes

Highly Dispersive Metal Atoms Anchored on Carbon Matrix Obtained by Direct Rapid Pyrolysis of Metal Complexes

Experimental investigations on sugarcane bagasse pyrolytic oil production from flash pyrolysis using a rotary screw reactor

AbstractA rotary screw pyro‐oil reactor was designed for powdery biomass for a feeding capacity of 40 kg h−1 with a moisture content of <10%. The pyro‐oil reactor temperature was maintained at 450–550 °C. The pyro‐oil vapors produced were quickly drafted out of the reactor for quenching to yield 16–24 L h−1 from 40 kg h−1 of biomass feed. The flash‐pyrolysis technique, which is capable of directly turning biomass into a liquid fuel, was used to produce liquid fuel (bio‐oil). It was carried out at a pressure at 0.03 bar and at a medium temperature of about 550 °C. The flash‐pyrolysis technique converts the entire biomass matter, excluding the ash. In this method the powdery biomass is converted into three components: bio‐oil (the yield is typically 70% on an energy basis, a powdery biomass feed at a moisture content of 10%); pyrolysis gas (typical yield 14%) and char (typical yield 16%). The temperature of the fixed bed was adjusted in the experiment, but the other variables remained constant, such as the amount of feed, the pyrolysis time of the gas product, the reactor pressure and the bed height. A biomass particle size range of 1–3 mm and a biomass residence time of 20 s in the reactor resulted in optimal bio‐oil production of 70%. This work demonstrated how precise pyrolysis mechanism processes and bio‐oil yields can influence the maximal reaction temperature in the 450–550 °C range. The performance analysis reveals that the fixed bed reaction temperatures of biomass rapid pyrolysis give reliable control over the bio‐oil reactor type and size. This paper provides an overview of the design and thermochemical liquefaction process used to convert powdered biomass to biofuel. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd

Synthesis of Nanostructured Boron Nitride Aerogels by Rapid Pyrolysis of Melamine Diborate Aerogels via Induction Heating: From Composition Adjustment to Property Studies

Synthesis of Nanostructured Boron Nitride Aerogels by Rapid Pyrolysis of Melamine Diborate Aerogels via Induction Heating: From Composition Adjustment to Property Studies

Catalytic upgrading of coal volatiles with Fe2O3 and hematite by TG-FTIR and Py-GC/MS

Pyrolysis plays a critical role in clean coal technology and energy conversion and is also conducive to the early peaking of carbon dioxide emissions. Light tar production from traditional coal pyrolysis using various iron-based catalysts for chemicals and fuel oil has gained attention recently. In this study, waste hematite was initially used for catalytic upgrading of rapid coal pyrolysis. Subsequently, thermogravimetric analyzer coupled with Fourier-transform infrared spectrometry (TG-FTIR) and pyrolysis gas chromatography mass spectrometry (Py-GC/MS) were utilized to compare the performances, kinetic parameters, and volatile composition of coal pyrolysis with Fe2O3 and hematite. The results showed that the maximum weight loss rate of coal pyrolysis increased by 1.55 %/min and 0.32 %/min with the addition of Fe2O3 and hematite, respectively, indicating that the pyrolysis reaction became more rapid and intense with iron-based catalysts. Both Kissinger Akahira Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods revealed that the catalysts reduced the apparent activation energy of coal pyrolysis. Online FTIR showed the emission temperature and content of coal volatiles, suggesting iron-based catalysts were conducive to the cracking of oxygen-containing functional groups and the directional cracking of groups to CO. Py-GC/MS illustrated the presence of Fe2O3 and hematite could reduce polycyclic aromatic hydrocarbons and oxygenates. In addition, a mechanism for rapid coal pyrolysis with iron-based catalysts was proposed to provide fundamental information for the transformation of aliphatic hydrocarbons, oxygenates, and polycyclic aromatic hydrocarbons. It is believed that iron-based catalysts have great potential for future research on upgrading coal volatiles and tar.

Paleo-oil reservoir pyrolysis and gas release in the Yangtze Block imply an alternative mechanism for the Late Permian Crisis

The causes of the global mass extinction that occurred around the Permian–Triassic boundary have been widely studied through the geological record and in various locations. The results show that volcanic activity was a key factor in initiating the crisis during the Late Permian. Compared to other thermal events triggered by volcanic activity, pyrolysis of petroleum in Pre-Permian reservoirs has rarely been suggested as a significant source of the greenhouse gases that caused the mass extinction. In this study, geochemical analysis is carried out of a huge paleo-oil reservoir in the Yangtze Block (YB), South China. The detection of mineral inclusions and pyrobitumens is evidence of rapid pyrolysis of accumulated oil in the Ediacaran reservoir. New evidence from hydrothermal minerals and the presence of domain mesophase in the pyrobitumen suggest that the pyrolysis process occurred abruptly and that greenhouse gases were rapidly released through venting pipes. The dating of such a complex geological event in this old and deeply buried reservoir is inevitably difficult and potentially unreliable. However, cross-validation of the multiple evidence sources, including hydrothermal minerals and domain mesophase, indicates that the rapid oil pyrolysis must have been driven by a major thermal event. Reconstruction of burial and thermal histories suggests that the thermal event was most likely to have been triggered by the Emeishan Large Igneous Province (ELIP), which was in a period of significant volcanic activity during the Late Permian. Massive volumes of gases, including methane, carbon dioxide, and possibly hydrogen sulfide, were released, causing a significant increase in greenhouse gases that may have contributed to global warming and the resulting mass extinction during the Late Permian Crisis (LPC).