Pyrolysis Of Organic Matter Research Articles

Chemical and Physical Properties of Selected Biochar Types and a Few Application Methods in Agriculture

Biochar, a carbon-rich by-product of organic matter pyrolysis, has a variety of physiochemical properties beside a variety of applications. This review highlights some physical and chemical characteristics of herbaceous, woody, and sewage waste biochar under different pyrolysis conditions, as well as soil and foliar applications of biochar. The controlling role of pyrolysis temperature was the reason for selecting the discussed biochar types in the study. This review concludes that increasing pyrolysis temperature mainly raised the values of some chemical properties of the biochar, such as pH, electrical conductivity (EC), ash content, total phosphorus (TP), and a few values of physical properties like porosity and specific surface area (SSA). On the other hand, yield and total nitrogen (TN) decreased with rising pyrolysis temperature. Among biochar application methods to soil, mixing biochar with soil before planting is one of the best methods of application, and in most cases, biochar reapplication improved soil properties, while foliar application of biochar has positive effects on plant growth and yield parameters, ranging from low rates to the highest ones.

Evolution of pore structure and diagenetic stages of late Permian shales in the Lower Yangtze Region, South China

This study examines the evolution characteristics of shale pores in the Late Permian Longtan Formation located in the Lower Yangtze region of South China. The complete process of thermal evolution of the samples was achieved through thermal simulation experiments while identifying qualitatively the pore types and their development characteristics using field emission-scanning electron microscope (FE-SEM). Quantitative analysis of pore size distribution was conducted through mercury intrusion capillary pressure (MICP), nitrogen (N2) and carbon dioxide (CO2) adsorption experiments. The paper comprehensively analyzed the pore evolution characteristics and controlling factors of shale in the study area, with an analysis of diagenetic differences. Findings reveal that during the pore evolution process, both morphology and pore size are influenced by thermal maturity. The pore volume is dominated by mesopores and macropores, while the specific surface area is mainly dominated by mesopores and micropores. Thermal evolution promotes the formation of micropores and mesopores but hinders the development of macropores. Moreover, clay minerals transformation and mineral dissolution make certain contributions to the development of micropores. The diagenesis in the study area is controlled primarily by the pyrolysis of organic matter. Pyrite and clay minerals are the first to dissolve, followed by calcite and quartz. Five stages of evolution characterization have been identified from low-mature stage (Ro = 0.88 %) to overmature stage (Ro = 3.35 %) in combination with diagenesis. The development of pore structure and its influencing factors vary across different stages. The influencing factors mainly include hydrocarbon generation from organic matter, compaction, mineral transformation, and dissolution. The process of hydrocarbon generation in organic matter occurs throughout the entire pore evolution process, resulting in the development of numerous micropores and mesopores. Compaction primarily impacts pore development during the early diagenetic stage, causing a substantial transition of primary mineral pores from macropores to mesopores. Mineral transformation and dissolution take place during and after the middle diagenetic stage. The former governs the development of mesopore-sized clay interlayer pores, while the latter primarily generates micropores.

Kinetics study on supercritical water conversion of low-maturity shale for hydrogen-rich hydrocarbon gas generation

Supercritical water (SCW) has gained substantial interest for shale exploitation due to its high conversion efficiency. To quantify the generated gases and the mutual conversion of gases on reaction of shale in SCW, experiments were carried out in batch reactor at 400–600°C and residence time up to 480 min. The products are classified as residual solids, liquid intermediates and gases. Experimental results show that the generated gases are mainly C1, C2, C3 alkanes, H2 and CO2. The concentrations of C1 and C2 alkanes decrease with temperature and residence time but the other three are the opposite. A kinetic model of shale-intermediates-gases reaction is developed. This model can characterize the gas generation features of shale and SCW resulting from chemical reactions, and can quantitatively describe the mutual conversion between gases. The calculated results demonstrate well applicative for predicting gas concentration at various residence time within an acceptable deviation. The reaction process can be divided into three stages: pyrolysis of organic matter to generate intermediates, hydrolysis reaction and alkyl thermal cracking of intermediates to generate gases, mutual conversion between the generated gases. Reactions among gases involve methanation reaction, water-gas shift reaction and hydrocarbon gas decomposition. This study provides a potential kinetic model for the gas generation characteristics of reaction with shale and supercritical water.

Effect of long reaction distance on gas composition from organic-rich shale pyrolysis under high-temperature steam environment

When high-temperature steam is used as a medium to pyrolyze organic-rich shale, water steam not only acts as heat transfer but also participates in the chemical reaction of organic matter pyrolysis, thus affecting the generation law and release characteristics of gas products. In this study, based on a long-distance reaction system of organic-rich shale pyrolysis via steam injection, the effects of steam temperature and reaction distance on gas product composition are analyzed in depth and compared with other pyrolysis processes. The advantages of organic-rich shale pyrolysis via steam injection are then evaluated. The volume concentration of hydrogen in the gas product obtained via the steam injection pyrolysis of organic-rich shale is the highest, which is more than 60%. The hydrogen content increases as the reaction distance is extended; however, the rate of increase changes gradually. Increasing the reaction distance from 800 to 4000 mm increases the hydrogen content from 34.91% to 69.68% and from 63.13% to 78.61% when the steam temperature is 500 °C and 555 °C, respectively. However, the higher the heat injection temperature, the smaller the reaction distance required to form a high concentration hydrogen pyrolysis environment (hydrogen concentration > 60%). When the steam pyrolysis temperature is increased from 500 °C to 555 °C, the reaction distance required to form a high concentration of hydrogen is reduced from 3800 to 800 mm. Compared with the direct retorting process, the volume concentration of hydrogen obtained from high-temperature steam pyrolysis of organic-rich shale is 8.82 and 10.72 times that of the commonly used Fushun and Kivite furnaces, respectively. The pyrolysis of organic-rich shale via steam injection is a pyrolysis process in a hydrogen-rich environment.

Long-Term Application of Biochar Mitigates Negative Plant-Soil Feedback by Shaping Arbuscular Mycorrhizal Fungi and Fungal Pathogens.

Negative plant-soil feedback (PSF) arises when localized accumulations of pathogens reduce the growth of conspecifics, whereas positive PSF can occur due to the emergence of mutualists. Biochar, a carbon-rich material produced by the pyrolysis of organic matter, has been shown to modulate soil microbial communities by altering their abundance, diversity, and activity. For this reason, to assess the long-term impact of biochar on soil microbiome dynamics and subsequent plant performance, we conducted a PSF greenhouse experiment using field soil conditioned over 10 years with Vitis vinifera (L.), without (e.g., C) or with biochar at two rates (e.g., B and BB). Subsequently, the conditioned soil was employed in a response phase involving either the same plant species or different species, i.e., Medicago sativa (L.), Lolium perenne (L.), and Solanum lycopersicum (L.). We utilized next-generation sequencing to assess the abundance and diversity of fungal pathogens and arbuscular mycorrhizal fungi (AMF) within each conditioned soil. Our findings demonstrate that biochar application exerted a stimulatory effect on the growth of both conspecifics and heterospecifics. In addition, our results show that untreated soils had a higher abundance of grape-specialized fungal pathogens, mainly Ilyonectria liriodendra, with a relative abundance of 20.6% compared to 2.1% and 5.1% in B and BB, respectively. Cryptovalsa ampelina also demonstrated higher prevalence in untreated soils, accounting for 4.3% compared to 0.4% in B and 0.1% in BB. Additionally, Phaeoacremonium iranianum was exclusively present in untreated soils, comprising 12.2% of the pathogens' population. Conversely, the application of biochar reduced generalist fungal pathogens. For instance, Plenodomus biglobosus decreased from 10.5% in C to 7.1% in B and 2.3% in BB, while Ilyonectria mors-panacis declined from 5.8% in C to 0.5% in B and 0.2% in BB. Furthermore, biochar application was found to enrich the AMF community. Notably, certain species like Funneliformis geosporum exhibited increased relative abundance in biochar-treated soils, reaching 46.8% in B and 70.3% in BB, compared to 40.5% in untreated soils. Concurrently, other AMF species, namely Rhizophagus irregularis, Rhizophagus diaphanus, and Claroideoglomus drummondii, were exclusively observed in soils where biochar was applied. We propose that the alleviation of negative PSF can be attributed to the positive influence of AMF in the absence of strong inhibition by pathogens. In conclusion, our study underscores the potential of biochar application as a strategic agricultural practice for promoting sustainable soil management over the long term.

Mitigation of cadmium-induced stress in maize via synergistic application of biochar and gibberellic acid to enhance morpho-physiological and biochemical traits

Cadmium (Cd), being a heavy metal, tends to accumulate in soils primarily through industrial activities, agricultural practices, and atmospheric deposition. Maize, being a staple crop for many regions, is particularly vulnerable to Cd contamination, leading to compromised growth, reduced yields, and potential health risks for consumers. Biochar (BC), a carbon-rich material derived from the pyrolysis of organic matter has been shown to improve soil structure, nutrient retention and microbial activity. The choice of biochar as an ameliorative agent stems from its well-documented capacity to enhance soil quality and mitigate heavy metal stress. The study aims to contribute to the understanding of the efficacy of biochar in combination with GA3, a plant growth regulator known for its role in promoting various physiological processes, in mitigating the adverse effects of Cd stress. The detailed investigation into morpho-physiological attributes and biochemical responses under controlled laboratory conditions provides valuable insights into the potential benefits of these interventions. The experimental design consisted of three replicates in a complete randomized design (CRD), wherein soil, each containing 10 kg was subjected to varying concentrations of cadmium (0, 8 and 16 mg/kg) and biochar (0.75% w/w base). Twelve different treatment combinations were applied, involving the cultivation of 36 maize plants in soil contaminated with Cd (T1: Control (No Cd stress; T2: Mild Cd stress (8 mg Cd/kg soil); T3: Severe Cd stress (16 mg Cd/kg soil); T4: 10 ppm GA3 (No Cd stress); T5: 10 ppm GA3 + Mild Cd stress; T6: 10 ppm GA3 + Severe Cd stress; T7: 0.75% Biochar (No Cd stress); T8: 0.75% Biochar + Mild Cd stress; T9: 0.75% Biochar + Severe Cd stress; T10: 10 ppm GA3 + 0.75% Biochar (No Cd stress); T11: 10 ppm GA3 + 0.75% Biochar + Mild Cd stress; T12: 10 ppm GA3 + 0.75% Biochar + Severe Cd stress). The combined application of GA3 and BC significantly enhanced multiple parameters including germination (27.83%), root length (59.53%), shoot length (20.49%), leaf protein (121.53%), root protein (99.93%), shoot protein (33.65%), leaf phenolics (47.90%), root phenolics (25.82%), shoot phenolics (25.85%), leaf chlorophyll a (57.03%), leaf chlorophyll b (23.19%), total chlorophyll (43.77%), leaf malondialdehyde (125.07%), root malondialdehyde (78.03%) and shoot malondialdehyde (131.16%) across various Cd levels compared to the control group. The synergistic effect of GA3 and BC manifested in optimal leaf protein and malondialdehyde levels indicating induced tolerance and mitigation of Cd detrimental impact on plant growth. The enriched soils showed resistance to heavy metal toxicity emphasizing the potential of BC and GA3 as viable strategy for enhancing maize growth. The application of biochar and gibberellic acid emerges as an effective means to mitigate cadmium-induced stress in maize, presenting a promising avenue for sustainable agricultural practices.

A Comprehensive Comparative Study on Pyrolysis Kinetics and Process of Organic‐Rich Mudstone and Kerogen via Thermogravimetry and Peak Deconvolution

Pyrolytic oil production from kerogens is of scientific and industrial importance for the efficient utilization of oil resources. Minerals exert a significant impact on this process. In this study, the pyrolysis kinetics and process of organic‐rich mudstones and kerogens in the Junggar basin are investigated by characterization and thermogravimetric experiments. The major minerals in the kerogen, except pyrite, are eliminated by HF/HCl treatment. To conduct a detailed comparison of the pyrolysis kinetics of rocks and kerogens, the pyrolysis process of kerogens is deconvoluted into two stages, including the pyrolysis oil production process and the conversion of sulfur compounds. The results show that the pyrolysis kinetics and reaction models of sulfur compounds differ significantly from those of the hydrocarbon production process. Furthermore, the effects of minerals on the pyrolysis products are analyzed using thermogravimetric‐Fourier‐transform infrared spectrometer. The main pyrolytic volatilization products include C2+ aliphatics, CH4, CO2, SO2, CO, and SO bonded substances. Minerals can increase the activation energy of organic matter pyrolysis, but the effect on the reaction model can be negligible. Moreover, minerals can promote the condensation dehydrogenation of aromatics and inhibit the cleavage of aliphatics. Notably, organic matter can act as active sites in the formation of sulfur compounds.

Toxicity and Behavioral Effects of Amending Soils with Biochar on Red Imported Fire Ants, Solenopsis invicta.

Solenopsis invicta, often known as the red imported fire ants (RIFAs), is a well-known global invasive ant species that can be found in agricultural, urban, and natural environments worldwide. Simultaneously, it also inhabits the soil. Biochar is generated by the pyrolysis of organic matter under high-temperature anoxic environments and widely used in agricultural ecosystems and soil amendment. However, to date, it remains unknown as to whether soil application of biochar has a negative effect on RIFAs. In our study, we investigated the toxicity and irritability effects of different amounts of biochar (0%, 1%, 2%, 5%, 10%, and 20%) introduced into the soil on red fire ants; upon comparison with the control soil (0% biochar), the application of 1%, 2%, and 5% biochar did not result in significantly different results. But the utilization of biochar at a concentration over 10% effectively repelled the RIFAs, resulting in their departure from the treated soils. High doses of biochar were able to cause death of red fire ants; the mortality rate of red fire ants reached 55.56% after 11 days of 20% biochar treatment. We also evaluated the effects of biochar on four behaviors of red fire ants, namely aggregation, walking, grasping, and attacking; 20% of the biochar treatment group reduced aggregation by 64.22% and this value was 55.22%, 68.44%, and 62.36% for walking, grasping, and attacking. Finally, we measured the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) enzyme activity and malondialdehyde (MDA) content in red fire ants; the results showed that the activities of the three enzymes increased with the increase in biochar addition, which indicated that a high dose of biochar induced oxidative stress in red fire ants. Our results indicate that biochar has the potential to cause toxicity and repel red imported fire ants (RIFAs) in a manner that is dependent on the concentration. We propose that biochar could be utilized in the control and manufacturing of baits for red fire ant management. This work establishes a foundation for the prevention and management of red fire ants and the logical utilization of biochar.

Origin of the Saibo-Lamasu Skarn Cu deposit, Western Tianshan, Xinjiang, NW China: Evidence from geology, mineral chemistry, fluid inclusions, stable isotopes, and organic geochemistry

The Saibo-Lamasu Cu deposit is the largest skarn Cu deposit in Western Tianshan, Xinjiang, NW China. The Cu orebodies are predominantly hosted in the contact zone between the oxidized granodiorite porphyry (lg fO2 = FMQ + 1.4 to 4.4) and reduced carbonaceous limestones (effective source rocks, TOC = 0.19 to 0.32 %). Three hydrothermal stages have been recognized: (1) The pre-ore stage skarn minerals in the proximal locations are dominated by andradite (And84Gro15Pyr1) and diopside (Di76-81Hd17-23Jo1-2), while that in the distal locations are mainly wollastonite, grossular (And15Gro83Pyr2), and hedenbergite (Di31-35Hd64-68Jo1-2). The coexistence of halite-bearing multiphase and vapor-rich fluid inclusions have similar total homogenization temperatures (Th) indicating that fluid boiling happened during this stage. (2) The syn-ore stage is typified by abundant sulfides and quartz. The coexistence of fluid inclusions representing trapped vapor (vapor-rich fluid inclusions) and liquid phases (liquid-rich fluid inclusions) showing similar Th implies the occurrence of a later boiling. (3) The non-boiling fluid inclusions in post-ore stage calcite are dominated by the liquid-rich fluid inclusions that have variable Th and relatively consistent salinities. The hydrothermal fluids are mainly magmatic water, the positive δ34S values of sulfides could reflect magmatic sulfur influenced by the interaction with wall rocks. The CH4 generated by the thermal pyrolysis of organic matter in carbonaceous limestones was dissolved in oxidized magmatic fluids that contributed to the change of skarn mineral assemblage and fluid characteristics on the temporal and spatial scales at the Saibo-Lamasu skarn Cu deposit.

Reaction Molecular Dynamics Study on the Mechanism of Alkali Metal Sodium at the Initial Stage of Naphthalene Pyrolysis Evolution

In order to study the role of metal sodium in the spray pyrolysis of biomass tar, this paper designs a sodium-containing naphthalene pyrolysis system (NSS) and a pure naphthalene pyrolysis system (PNS) using naphthalene as the carbon source and sodium chloride as the sodium metal donor for comparison. This enables an exploration of the effect of sodium on the initial nucleation of carbon fumes formed by naphthalene pyrolysis using reaction molecular dynamics (ReaxFF MD). The simulation results show that NSS undergoes pyrolysis reactions earlier and faster than PNS at the same temperature. Simulated at 3250 K temperature for 2 ns, the naphthalene pyrolysis consumption rate of the NSS was faster than that of the PNS, and the addition of sodium atoms during the condensation process provided more active sites and accelerated the condensation of macromolecular products. Moreover, Na+ and carbon rings form a Na+-π structure to promote the bending of graphite lamellae to facilitate the formation of carbon nuclei. Molecular dynamics simulations were used to simulate the formation of carbon nuclei during the initial stage of naphthalene pyrolysis, revealing that the mechanism of sodium salt catalyzed the acceleration of organic matter pyrolysis from a microscopic visualization perspective.

Effects of Biochar on Drought Tolerance of Pinus banksiana Seedlings

Drought is a major stressor of tree seedlings regarding both natural and artificial regeneration, especially in excessively drained, sandy outwash soils. While climate change is expected to cause an increase in the total annual precipitation in the Upper Midwest, USA, the timing of the precipitation is predicted to result in longer periods of drought during the growing season. Biochar, a material created through the pyrolysis of organic matter, such as wood waste, has been proposed as a soil amendment that may increase the water holding capacity of a soil. Biochar has mostly been studied in agricultural settings, and less is known about the impact of biochar on forest soils and tree seedlings. We used a greenhouse experiment to test the ability of biochar to improve the drought tolerance of jack pine (Pinus banksiana) seedlings via increased soil water holding capacity. The seedlings were planted in sandy soil treated with three levels of biochar (none, 3% by weight, and 6% by weight) in two experiments, one manipulating the timing of drought onset and the other controlling the amount of water that seedlings received. Our results showed no significant effects of biochar on seedling survival, growth, or physiology under drought conditions. While this outcome did not support the hypothesis that biochar would increase seedling performance, the biochar amendments did not negatively affect seedlings, indicating that biochar may be added to soil for carbon storage without having negative short-term impacts on tree seedlings.

Evolution of organic carbon isotopes during the pyrolysis of Nongan oil shale in Songliao Basin and its implications for in-situ conversion project

Mastering the reaction process of underground pyrolysis is the key to oil shale in-situ conversion project. The progress of the pyrolysis reaction can be analyzed by the information of the kerogen maturity in the reaction formation. However, it is difficult to directly test the kerogen maturity by drilling and coring in in-situ conversion project. And the research on judging the process of underground pyrolysis reaction according to the maturity of oil and gas products has not been carried out in depth. This project intends to take the oil shale of the Nenjiang Formation in the southern Songliao Basin and the pyrolysis oil samples produced by the in-situ conversion project as the research object, and conduct simulation experiments and test analysis. The purpose of this paper is to identify the dynamic evolution characteristics of carbon isotope fractionation during the evolution of oil shale pyrolysis hydrocarbon products, and then establish the response relationship with the process of oil shale organic matter pyrolysis. This study has formed a set of dynamic monitoring methods for the in-situ conversion of oil shale to organic matter pyrolysis reaction process, and laid a theoretical foundation for the efficient, economical and stable operation of oil shale in-situ conversion projects.

In situ self-assembly preparation and characterization of CaO–ZrO2 nanopowders under vacuum

CaO–ZrO2 nanocomposite powders were prepared by in situ self-assembly method under vacuum. The effects of calcium oxide content on the physical phase composition and microscopic morphology of the as-prepared nanopowders were investigated. The results showed that the content of the tetragonal phase in the powders gradually increased with increasing calcium oxide content. When the calcium oxide content reached 10 wt%, the prepared CaO–ZrO2 nanopowders were a pure tetragonal phase with good dispersion and average particle size about 57 nm. In comparison to the situation in air, the amorphous carbon particles formed by the pyrolysis of organic matter under vacuum were evenly distributed on the surface of the nanocomposite particles or between them. In this way, direct contact of the nanoparticles was avoided, thus inhibiting their rapid growth at high temperatures and facilitating the formation of fine grains with high surface energy. The preliminary results indicated that the smaller average particle size and narrower particle size distribution of the nanocomposite powders prepared in vacuum were significantly beneficial for improving the bending strength of the nanoceramic products compared to that in air. It is expected to provide valuable information for further optimization of the controllable preparation of high-quality nanoceramic powders.

High-Temperature-Induced Pore System Evolution of Immature Shale with Different Total Organic Carbon Contents.

The pyrolysis process of source rock, especially organic-rich immature shale, is required for oil and gas extraction, during which the evolution of the pore structure system in the immature shale determines the heat conduction and fluid flow under the heating treatment. Although some sound achievements have been made regarding the pyrolysis of immature shale, the effect of the total organic carbon (TOC) content on the pore structure evolution of immature shale remains unclear. With respect to this issue, in this work, a series of N2 adsorption/desorption and nuclear magnetic resonance (NMR) experiments were conducted, and fractal dimension theory was also introduced to analyze the pore structure evolution of immature shale subjected to heating treatment in a quantitative manner. The results indicate that the adsorption branch of the nitrogen adsorption-desorption isotherm can be divided into three stages. The pore structure of different TOC immature shales does not change significantly, and they are all slit-shaped. In addition, immature shale with a higher organic content has a higher hydrocarbon expulsion strength and a higher pore volume growth rate, which indicate that the pyrolysis of organic matter greatly affects the pore structure of immature shale during heating. This phenomenon shows that the pyrolysis of organic matter greatly influences the pore structure of immature shale during the heating process. The pores of immature shale in the study area have significant fractal characteristics, the fractal dimension is between 2.397 and 2.636, the pore space of the sample is extremely small, the pore structure is extremely complex, and the heterogeneity is strong.

Biochar Applications in Soil Restoration: Enhancing Soil Health and Carbon Sequestration

Soil health degradation, driven by intensive agriculture, deforestation, and climate change, has become a pressing global issue, demanding sustainable restoration solutions. Biochar, a carbon-rich material produced via pyrolysis of organic matter, has garnered attention as a potent soil amendment. It offers significant benefits, including improved soil structure, enhanced nutrient retention, increased water-holding capacity, and better crop productivity. Additionally, biochar plays a crucial role in carbon sequestration, thereby contributing to climate change mitigation. This article reviews the applications of biochar in soil restoration and examines the mechanisms through which it enhances soil health. It discusses how biochar contributes to long-term carbon storage in soils, reduces greenhouse gas emissions, and supports soil microbial activity. Furthermore, the review highlights biochar’s role in rehabilitating degraded agricultural lands, restoring ecosystems, and remediating contaminated urban soils. While biochar presents numerous benefits, its large-scale adoption faces challenges such as variability in its properties based on production methods, high production costs, and the need for long-term impact studies. The article outlines these challenges and offers directions for future research, including optimizing biochar production, standardizing its application, and exploring its interactions with different soil types and ecosystems.

Lithofacies Characteristics and Pore Controlling Factors of New Type of Permian Unconventional Reservoir in Sichuan Basin

Alongside volcanic eruptions in the middle and late Permian, the sedimentary environment and process changed, and the lithofacies characteristics varied conspicuously in the marine deposits of the Sichuan Basin (China). The tuffaceous rocks, as a new type of unconventional reservoir, provide strong evidence for marine and volcanic influences on the lithology and reservoir potential of the rocks. With experimental studies relying on field outcrops, thin sections, scanning electron microscopy and whole-rock X-ray diffraction (XRD), the researchers analyzed the lithofacies characteristics, pore types and controlling factors on the various types of pores in the tuffaceous rocks. We identified three lithofacies types in this new type of Permian reservoir in the Sichuan Basin, namely tuff, sedimentary tuff, and tuffaceous mudstone. The mineral composition of the three lithofacies includes quartz, feldspar, carbonate minerals, pyrite, and clay, among which feldspar is mainly potassium feldspar. Tuff has high tuff content, and the lowest clay and TOC content; tuffaceous mudstones have the highest clay and TOC content, and the lowest tuff content. The pore types of the tuffaceous rocks are mainly nano-scale shrinkage pores, with a small number of intergranular pores including intragranular pores, intergranular pores, and organic pores. The shrinkage pores account for 81.9% of the total pores, and organic pores account for 11.2% of the total pores. In the tuffaceous rocks, the tuff content, quartz and feldspar content, and pyrite content are inversely correlated with porosity, while the clay content and TOC content are positively correlated with porosity. The porosity of tuff is the lowest, followed by sedimentary tuff, and the porosity of tuffaceous mudstone is the highest. Tuffaceous rocks form many micropores in the process of devitrification. Organic matter pyrolysis and organic acid dissolution also increase the reservoir space and porosity of the reservoir. This new type of reservoir has the ability of hydrocarbon accumulation along with the reservoir performance, and thus it has greater exploration prospects.

Thermal and nonthermal effect of microwave irradiation on the pore microstructure and hydrocarbon generation of organic matter in shale

In situ heating conversion is the most effective means to develop medium-low maturity shale oil. Herein, the effects of microwave irradiation on the shale pore structure and hydrocarbon generation of organic matter were studied using an independent development microwave device in combination with Rock-Eval, Leco analysis, X-ray diffraction, field emission scanning electron microscopy, low-temperature N2 adsorption/desorption, nuclear magnetic resonance, Fourier transform infrared spectroscopy and kinetic simulation of hydrocarbon generation. The results show that microwave irradiation can effectively heat shale and the temperature can rise to hundreds of degrees Celsius in a short time (10 min), with 400 °C as the best temperature for in situ conversion of medium-low maturity shale, at which the pore volume and surface area reach the maximum. Microwave irradiation is conducive to pyrolysis and hydrocarbon generation of aliphatic structure in shale organic matter. There are differences in the response of different organic components to the nonthermal effect of microwave irradiation, which reduces the activation energy of hydrocarbon generation during organic matter pyrolysis. Heating shale by microwave irradiation can effectively promote organic matter pyrolysis and hydrocarbon generation, improve rock reservoir and seepage capacity, and is of great significance for the efficient development of shale oil.

FirstIn SituTerrestrial Osbornite (TiN) in the Pyrometamorphic Hatrurim Complex, Israel

AbstractOsbornite (TiN) is extremely rare in nature (commonly found in enstatite meteorites) and has not yet been identified correctly to form naturally in terrestrial settings. Due to its thermodynamic stability and thermal shock resistance, TiN has wide industrial applications, mainly as coatings. However, as the melting temperature of TiN is very high (~3000°С), coatings are produced at much lower temperatures via physical or chemical vapor deposition. Also, anthropogenic analogues of osbornite are often observed in pyrometallurgical slags. Therefore, it is critical to distinguish between anthropogenic and naturally occurring osbornite. A detailed petrographic study was undertaken on in situ osbornite found within unusual gehlenite-bearing breccias from wadi Zohar, Negev Desert of the pyrometamorphic Hatrurim Complex. The Hatrurim Complex, which extends through Israel, Palestine, and Jordan within the Dead Sea Rift zone, mainly comprises larnite, gehlenite, and spurrite rocks. Osbornite, in close association with iron phosphides, barringerite, and schreibersite, occurs at contacts between gehlenite, paralava, and calcinated clasts of host sedimentary rocks. Based on investigation of pseudowollastonite and Fe-P series phases, osbornite is formed at low pressure, extremely high temperatures (~1200-1500°С), and reduced conditions, following pyrolysis of organic matter contained in the sedimentary protolith. This is the first identification of in situ osbornite in terrestrial rocks and indicates that high-temperature and highly reduced conditions, which are common for meteorites, may occur at/near the Earth’s surface as a result of sustained pyrometamorphism in particular settings. Our findings also provide relevant data and criteria for comparing osbornite occurrences elsewhere and ultimately evaluating their origins.

Spark plasma sintering mechanism of Al2O3-based ceramics granulation powder

In this paper, spark plasma sintering (SPS) was used for the first time to rapidly densify Al2O3-based granulated powders at different temperatures, and the sintering mechanism of SPS was analyzed. It is found that the optimum sintering temperature of ceramic materials is 1450 °C. Under the action of rapid heating rate (100 °C/min) spark sintering and strong electric field generated by low temperature and large current, the transport and migration of substances are accelerated, and the grains can grow effectively. The slip rearrangement between the particles caused by the discharge effect promotes the discharge of all the gases produced by the pyrolysis of organic matter, and finally the sintering densification degree of the material is optimized.

Thermoacoustic emission characteristics and real-time damage evolution in shales of the Lower Palaeozoic Niutitang Formation

Identifying shale geological temperatures is important for understanding the thermal maturity, thermal evolutionary history, and hydrocarbon generation stages of shale formations, and enables efficient shale gas development. This paper investigates the thermal Kaiser effect of shales under different warming rates by studying the thermoacoustic emission (TAE) characteristics of shales in the Lower Palaeozoic Niutitang Formation in the Micangshan area of China. The developmental evolution and microscopic response mechanisms of different types of fractures in shales under high-temperature conditions are explored by combining acoustic emission (AE) characteristic parameters. The memory and sensitivity of the thermal Kaiser effect were also verified by thermal fatigue tests. The results show that there is a significant thermal Kaiser effect during the heating of shale and that its threshold temperature is approximately 180 °C, which is consistent with the palaeotemperatures based on bitumen reflectance (Rb) estimation. The heating rate does not have a significant effect on the threshold temperature. At high temperatures, the shale is dominated by small-scale tensile fractures. When the shale is heated to 300 °C, the organic matter reaction rate peaks and the proportion of shear cracks begins to increase. An increase in heating rate is beneficial to the development of large-scale tensile cracks, while inorganic minerals begin to expand due to heat and micro-cracks gradually expand and connect, thus improving the connectivity of the pore channels. In thermal fatigue tests, the shale retains its memory of the threshold temperature when heated to less than 300 °C. Above 300 °C, pyrolysis of organic matter and microcrack expansion interfere with the thermal Kaiser effect, causing the shale to lose its memory of the maximum temperature. Within the same cycle stage, the threshold temperature is significantly higher at high heating rates than at low ones, especially above 400 °C.