Catalytic Hydropyrolysis Research Articles

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

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

Synthesis of sustainable aviation biofuels via catalytic hydropyrolysis of lignin

The exploitation of bimetallic catalysts to lignin for sustainable aviation biofuels remains a daunting challenge due to the low selectivity of aviation biofuel-range hydrocarbons and inconsistent reaction mechanism. Herein, bimetallic supported on SiO2 catalysts were prepared and their hydrodeoxygenation reactivity during lignin catalytic hydropyrolysis was explored. Approximately 100 % selectivity toward aviation-range hydrocarbons were achieved using eugenol as model compound under relatively mild conditions with the presence of NiMo/SiO2. For lignin catalytic hydropyrolysis, the yield of liquid hydrocarbons and the selectivity of aviation-range hydrocarbons was 21.99 wt% and 70.50 %, respectively. High mass balance (89.66 %) was verified by scale-up experiments in a continuous flow high-pressure reactor system. The reactivity of demethoxylation reaction, dehydroxylation reaction, and benzene ring hydrogenation reaction with the presence of bimetallic catalysts were analyzed. The density functional theory calculation and verification experiments revealed the evolution pathway of aromatic hydrocarbons and cycloalkanes from lignin catalytic hydropyrolysis. The proposed reaction mechanism can provide guidance for the regulation of aviation biofuel components from lignin catalytic hydropyrolysis.

A critical review on direct catalytic hydrogasification of coal into CH4: catalysis process configurations, evaluations, and prospects

Coal catalytic hydrogasification (CCHG) is a straightforward approach for producing CH4, which shows advantages over the mature coal-to-CH4 technologies from the perspectives of CH4 yield, thermal efficiency, and CO2 emission. The core of CCHG is to make carbon in coal convert into CH4 efficiently with a catalyst. In the past decades, intensive research has been devoted to catalytic hydrogasification of model carbon (pitch coke, activated carbon, coal char). However, the chemical process of CCHG is still not well understood because the coal structure is more complicated, and CCHG is a combination of coal catalytic hydropyrolysis and coal char catalytic hydrogasification. This review seeks to shed light on the catalytic process of raw coal during CCHG. The configuration of suitable catalysts, operating conditions, and feedstocks for tailoring CH4 formation were identified, and the underlying mechanisms were elucidated. Based on these results, the CCHG process was evaluated, emphasizing pollutant emissions, energy efficiency, and reactor design. Furthermore, the opportunities and strategic approaches for CCHG under the restraint of carbon neutrality were highlighted by considering the penetration of “green” H2, biomass, and CO2 into CCHG. Preliminary investigations from our laboratories demonstrated that the integrated CCHG and biomass/CO2 hydrogenation process could perform as an emerging pathway for boosting CH4 production by consuming fewer fossil fuels, fulfilling the context of green manufacturing. This work not only provides systematic knowledge of CCHG but also helps to guide the efficient hydrogenation of other carbonaceous resources such as biomass, CO2, and coal-derived wastes.

Challenges and Perspectives of the Conversion of Lignin Waste to High-Value Chemicals by Pyrolysis

The pyrolysis process is a thermochemical conversion reaction that encompasses an intricate array of simultaneous and competitive reactions occurring in oxygen-depleted conditions. The final products of biomass pyrolysis are bio-oil, biochar, and some gases, with their proportions determined by the pyrolysis reaction conditions and technological pathways. Typically, low-temperature slow pyrolysis (reaction temperature below 500 °C) primarily yields biochar, while high-temperature fast pyrolysis (reaction temperature 700–1100 °C) mainly produces combustible gases. In the case of medium-temperature rapid pyrolysis (reaction temperature around 500–650 °C), conducted at very high heating rates and short vapor residence times (usually less than 1 s), the maximum liquid yield can reach up to 85 wt% (on a wet basis) or achieve 70 wt% (on a dry basis), with bio-oil being the predominant product. By employing the pyrolysis technique, valuable utilization of tobacco stem waste enriched with lignin can be achieved, resulting in the production of desired pyrolysis products such as transportation fuels, bio-oil, and ethanol. The present review focuses on catalytic pyrolysis, encompassing catalytic hydropyrolysis and catalytic co-pyrolysis, and meticulously compares the impact of catalyst structure on product distribution. Initially, we provide a comprehensive overview of the recent pyrolysis mechanism of lignin and tobacco waste. Subsequently, an in-depth analysis is presented, elucidating how to effectively design the catalyst structure to facilitate the efficient conversion of lignin through pyrolysis. Lastly, we delve into other innovative pyrolysis methods, including microwave-assisted and solar-assisted pyrolysis.

Customized Atmospheric Catalytic Hydropyrolysis of Biomass to High-Quality Bio-Oil Suitable for Coprocessing in Refining Units

Customized Atmospheric Catalytic Hydropyrolysis of Biomass to High-Quality Bio-Oil Suitable for Coprocessing in Refining Units

Carbonaceous matter in ∼ 3.5 Ga black bedded barite from the Dresser Formation (Pilbara Craton, Western Australia) – Insights into organic cycling on the juvenile Earth

Carbonaceous matter (CM) in Archean rocks represents a valuable archive for the reconstruction of early life. Here we investigate the nature of CM preserved in ∼ 3.5 Ga old black bedded barites from the Dresser Formation (Pilbara Carton, Western Australia). Using light microscopy and high-resolution Raman mapping, three populations of CM were recognized: (i) CM at the edges of single growth bands of barite crystals (most frequent), (ii) CM within the barite matrix, and (iii) CM in 50–300 µm wide secondary quartz veins that cross-cut the black bedded barite. Raman spectra of CM inside black bedded barite indicated peak metamorphic temperatures of ∼ 350 °C, consistent with those reached during the main metamorphic event in the area ∼ 3.3 Ga ago. By contrast, CM in quartz veins yielded much lower temperatures of ∼ 220 °C, suggesting that quartz-vein associated CM entered the barite after 3.3 Ga. Near edge X-ray absorption fine structure (NEXAFS) and solid-state nuclear magnetic resonance (NMR) revealed a highly aromatic nature of the CM with a lower aliphatic content, which is in line with the relatively elevated thermal maturity. Catalytic hydropyrolysis (HyPy) did not yield any hydrocarbons detectable with gas chromatography–mass spectrometry (GC–MS). Secondary ion mass spectrometry (SIMS) based δ13C values of individual CM particles ranged from − 33.4 ± 1.2 ‰ to − 16.5 ± 0.6 ‰ and are thus in accordance with a biogenic origin, which is also consistent with stromatolitic microbialites associated with the black bedded barite. Based on these results we conclude that CM at growth bands and inside the barite matrix is syngenetic and only the CM inside quartz veins, which represents a minor portion of the total CM, is a later addition to the system. Furthermore, we discuss different pathways for the input of CM into the barite-forming environment, including the cycling of biological organic material within the hydrothermal system.

Catalytic pyrolysis of biomass to produce bio‐oil using layered double hydroxides (LDH)‐derived materials

AbstractOwing to the enormous consumption of petroleum products and their environmental polluting nature, attention has been given to seeking alternative resources for the development of sustainable products. Biomass is a renewable source that can be converted to a variety of fuels and chemicals by different approaches, which are the best replacements for traditional petroleum‐derived products. Pyrolysis is a process in which chemical bonds of biomass macromolecules such as cellulose, hemicellulose, and lignin, are fractured into small molecular intermediates under high pressure, and results bio‐oil, biochar, and fuel gases as desired products. Of these pyrolysis products, bio‐oil is the primary product that usually contains large amounts of oxygen and nitrogen compounds that hinder its application potential. Catalytic pyrolysis is a beneficial method that is reported to alter the constituents and quality of bio‐oil and to upgrade them for diverse applications. Catalytic hydropyrolysis and copyrolysis of biomass are an alternative approaches to overcome the drawbacks raised toward product formation in the pyrolysis process. Layered double hydroxides (LDH) and their derived forms are well‐known catalytic/catalytic support materials for various chemical reactions due to their superior properties, such as easy preparation, thermal stability, and tuneable acid/base properties. This review summarizes the progress in the utilization of as‐synthesized LDH and their modified forms such as mixed metal oxides and functionalized/composite materials as active catalysts for the pyrolysis of various biomass sources.

Simultaneous removal of brominated and chlorinated species during the production of oils by e-waste plastics catalytic hydropyrolysis

The production of added-value chemicals via pyrolysis of plastic wastes, such as those from electrical and electronic equipment (WEEE), needs addressing their usual contamination with halogens (mainly Br and Cl). This work compares the conversion via pyrolysis and hydropyrolysis of a real WEEE plastic, having a complex composition, in two different reactor configurations: down-flow (DF) and up-flow (UF). Likewise, the effects of incorporating a Pd/Al2O3 catalyst and using two different pressures (1 and 6 bar) have been assessed. With the DF mode, pyrolysis at 1 bar leads to an oil yield above 80 wt% and a total halogen content of about 600 ppm (vs 1600 ppm in the water-washed WEEE plastic). Under DF catalytic hydropyrolysis at 6 bar, this high oil yield is maintained while its dehalogenation degree is improved (142 ppm). Operating with the up-flow configuration, under 6 bar and H2 presence, leads to some reduction in the oil yield (about 70 wt%) but significantly decreases the oil halogen content (55 ppm Cl and total elimination of Br). These results have been related to the slower pyrolysis and longer residence time in the thermal zone of the UF configuration, which favours the halogen-trapping effect of the char fraction, and the pressure-enhanced hydrodehalogenation activity of the catalyst. This study highlights the environmental benefits of the proposed process, emphasizing the lower halogen content in the resulting oils and promoting a more sustainable approach to plastic waste valorisation.

Unlocking the potential of the bioeconomy for climate change reduction: The optimal use of lignocellulosic biomass in Germany

AbstractThe concept of a circular bioeconomy has become a new economic leitmotif for reducing greenhouse gas (GHG) emissions. Its central narrative rests on the idea of replacing fossil resources with biobased ones for a broad spectrum of products including, for example, heat, electricity, fuels, plastics, or chemicals. Yet, the amount of available bio‐resources is limited, rendering some technologies successful while leaving behind others. Lignocellulosic biomass (LBM) is a key resource already used on a large scale for heating purposes or electricity production and increasingly for the production of chemicals and biofuels. Because market mechanisms do not necessarily drive a cost‐optimal use with respect to their GHG‐reduction potential, a new bi‐objective linear optimization model under long‐term scenarios was developed for Germany accounting for competition with non‐biobased technologies. In the biofuels and biochemicals sectors, multi‐output processes that address industrial symbiosis and fossil references are used to compute profits and GHG emission savings of biobased products. However, in the absence of a reference for heat, a detailed representation of the heat sector is used in which heat demand for 19 subsectors is met, thus deriving costs and emission savings endogenously. When explicitly accounting for GHG emission reduction targets, biomass is optimally used in high‐temperature industries whereas heat pumps dominate in building heat. Because of the optimal use of biomass in industrial usage, subsidies for biomass heating are found to be inefficient in the building sector. Catalytic hydropyrolysis to produce biogasoline and biodiesel using LBM dominates the production of biofuels while biochemicals—strongly depending on oil price developments—will become competitive on a large scale after 2030.

Global trends of pyrolysis research: a bibliometric analysis

Pyrolysis has become an interesting waste valorization method leading to an increasing number of research studies in this field in the last decade. The present study aims to provide a comprehensive knowledge map of scientific production in pyrolysis, discuss the current state of research, and identify the main research hotspots and trends in recent years. The systematic review, supported by analysis of countries and institutions, keyword co-occurrence analysis, analysis of keyword trends, journal analysis, and article impact, was carried out on 6234 journal articles from the Science Citation Index Expanded database of the Web of Science Core Collection. As a result, four main research hotspots were identified: 1) characterization techniques and pyrolysis kinetic models, 2) biochar production and its main applications, 3) bio-oil production and catalytic pyrolysis, and 4) co-pyrolysis, which has become a consolidated research hotspot since 2018. Additionally, the main challenges and opportunities for future research have been identified, such as 1) the development of multi-step kinetic models for studying complex wastes, 2) the integration of biochar into other valorization processes, such as anaerobic digestion, and 3) the development of catalytic hydropyrolysis for the valorization of organic waste. This bibliometric analysis provides a visualization of the current context and future trends in pyrolysis, facilitating future collaborative research and knowledge exchange.

Thermal and catalytic fast hydropyrolysis of lignin: Optimization for selective production of aromatics using high-pressure tandem μ-reactor – gas chromatography/mass spectrometry

Hydropyrolysis is a promising route for converting biomass into valuable chemicals. A high-pressure tandem μ-reactor – gas chromatography/mass spectrometry was used to study the pyrolysis of lignin and probe the effects of reaction atmosphere (H2 vs He), temperature, catalyst (HZSM-5) presence/absence, and pressure on product yields and distributions. Hydropyrolysis favored the demethoxylation and demethylation of guaiacyl-derived intermediates, generating catechol- and phenol-type compounds. The yields of guaiacyl- and catechol-type compounds decreased with increasing temperature and H2 pressure. The products formed at the highest examined temperature (700 °C) and H2 pressure (3.0 MPa) were dominated by phenol-type compounds, monoaromatic hydrocarbons (MAHs), and polycyclic aromatic hydrocarbons (PAHs). The substantial decrease in char yield with increasing H2 pressure at 700 °C indicated that active hydrogen radicals enhanced the cracking of lignin macromolecules and suppressed the condensation reactions to form char at high temperatures. HZSM-5 exhibited considerable hydrocracking activity for converting lignin pyrolysis vapor into aromatics, with an increase in H2 pressure further improving the formation of benzene, toluene, and xylenes (BTX) at the expense of phenolics. However, high catalytic upgrading temperatures favored the coupling reactions in the hydrocarbon pool, promoting the formation of PAHs. Evolved gas analysis showed that lignin hydropyrolysis involved two stages (at 250–500 and 500–800 °C), suggesting that the labile fraction of the nascent char underwent further hydrocracking at high pressure and temperature. The high production of BTX and naphthalenes through catalytic hydropyrolysis of lignin provides a promising route for the valorization of lignin-rich resources.

The evolution of the majiang paleoreservoir, west margin of xuefeng uplift: Insights from in situ calcite U–Pb dating and bitumen and shale trace element analysis

The Majiang Reservoir, situated within the Yangtze Block, is the largest paleoreservoir in the region. Employing a comprehensive methodology involving the analysis of trace and rare earth elements in bitumen and shale, in situ U–Pb dating of hydrocarbon-associated calcite, and incorporating previously published data on oil-source correlation and significant stages of reservoir development, we successfully reconstructed the complete evolution of the Majiang Reservoir quantitatively. The bitumen trace elements data show the ratio of V/(V + Ni) ranging from 0.64 to 0.82, Ni/Co exceeding 7.0 and Zr/Cr below 1.0. PAAS-normalized rare earth element distribution patterns of both bitumen and Cambrian shales present zig-zags distributions. In addition, biomarker distribution acquired by catalytic hydropyrolysis and bulk δ13C values of both bitumen and Cambrian shales (−29.1‰ to −34.7‰ vs −30.2‰ to −32.3‰) also show similarity. All the geochemical parameters together indicate that the primary source of bitumen stems from Early Cambrian shales. Integrating fluid inclusion analysis, specifically examining two Th groups with temperatures of 97.2 °C and 142.6 °C, and U–Pb dating on hydrocarbon-bearing calcite (∼300 Ma), referencing prior Re–Os dates on bitumen (∼430 Ma) and pyrobitumen (∼80 Ma) and quartz fluid inclusion Ar–Ar dating (∼225 Ma), we successfully reconstructed the entire hydrocarbon evolution. The findings reveal that initial oil generation occurred during the Caledonian event, followed by secondary continuous oil and gas generation and migration, influenced by the Indosinian event. The combination of fluid inclusion analysis and isotopic geochronology data exemplifies immense potential in precisely determining the progression of petroleum evolution.

Catalytic hydropyrolysis of biomass using natural zeolite-based catalysts

Natural clinoptilolite (coded as Escott), synthetic BEA, and mixed Escott-BEA zeolites supported nickel and iron catalysts were employed for catalytic hydropyrolysis of eucalyptus globulus leaves. Comparing non-catalytic pyrolysis and catalytic pyrolysis in N2, the use of catalysts along with H2 (30 bar) resulted in improved yields of liquid oil and gas products, with reduced production of biochar/coke. Moreover, the biochar from catalytic hydropyrolysis showed a higher mesopore surface area (97 m2/g) than non-catalytic biochar (74 m2/g). Incorporating a small amount of BEA into Escott weakens the metal-support interaction, enhances H2 adsorption activity and increases the catalyst acidity, leading to an improved aromatic monomers selectivity while preventing excessive cracking of liquid oil. Consequently, Ni-Fe/Escott-BEA catalyst shows the highest content of valuable liquid organic components. Ni-Fe/Escott, with the largest Ni particles and lowest acidity, exhibits higher selectivity to methane and naphthalenes products. In contrast, Ni-Fe/BEA with excessive acid sites exhibited significantly lower content of liquid organic products but higher yields of C2-C5 gas products and deposited carbon, primarily ascribed to its high acidity promoting coupling, cracking and deoxygenation reactions. The deactivation of Brønsted acid sites was more pronounced than Lewis acid sites, underscoring their crucial role in coupling reactions and leading to increased coke deposition.

Catalytic hydropyrolysis of lignin: Insights into the effect of Ni catalyst and hydrogen using ReaxFF molecular dynamics simulation

Catalytic hydropyrolysis (CHP) of lignin as an emerging technology provides an efficient way of utilizing waste resources and promoting the production of alternative fuels and valuable bio-based products. The reinforcement of selective catalysts and hydrogen facilitates the overall conversion process but the mechanism remains difficult to clarify due to the complex nature of the system. This work employs a ReaxFF reactive molecular dynamics simulation method to explore the CHP of lignin dimer DMPD and the reaction mechanism at the molecular level. The results suggest that the hydropyrolysis (HP) system achieves a deoxygenation degree of 12.0 % for liquid products and the incorporation of hydrogen into pyrolysis suppresses the production of CO while promoting H2O and CH4 generation. The introduction of the Ni catalyst in the CHP system results in a liquid product yield of 68.9 wt % at 2000 K with a higher deoxygenation degree of 14.6 % due to the participation of a large amount of •H radicals species dissociated on the catalyst surface. The CHP reactions remarkably promote the production of phenols such as guaiacol and catechol and catechol is more likely to generate from the dynamic evolution of reaction intermediates. The integrated system also improves the production of H2O and light hydrocarbons like CH4 and C2H6. The first-order kinetic model reveals that the average activation energies of C-C, C-H, C-O bonds, and DMPD in the CHP system are significantly reduced to 113.12, 55.79, 59.99, and 132.17 kJ/mol in contrast to HP. The results indicate that the CHP system is more favorable for producing desirable liquid products with lower energy barriers.

High Phenol Yields from Catalytic Hydropyrolysis of Lignin and Phenolic-Rich Raffinate

High Phenol Yields from Catalytic Hydropyrolysis of Lignin and Phenolic-Rich Raffinate

Catalytic hydropyrolysis of biomass over NiMo bimetallic carbon-based catalysts

Catalytic hydropyrolysis (CHP) is an emerging and promising technology to convert lignocellulosic biomass resources into alternative fuels and valuable chemicals. In this work, NiMo bimetallic carbon-based catalysts were designed and applied in the thermal conversion of alkaline lignin at 450 °C, 500 °C, and 550 °C under 1 atm H2. The CHP process exhibited a higher deoxygenation extent of around 60% compared with pyrolysis (FP) and hydropyrolysis (HP) processes. The bio-oil with higher H/C ratio and lower O/C ratio corresponding to a chemical formula of CH1.167O0.245 was obtained at 500 °C over the IW catalyst prepared via incipient wetness impregnation. CO2 and CO were generated via the decarboxylation and decarbonylation reactions, respectively. As for the CHP of real biomass, the deoxygenation extent reached about 55% over different modified catalysts. The ball milling-melting catalyst showed a considerable liquid product yield of 35.0 wt% and the best bio-oil quality with the chemical formula of CH1.456O0.339. The remarkable hydrodeoxygenation activity of carbon-derived catalysts was attributed to the synergistic effect of metallic Ni0 and intermediate oxidation state of Mo2+/Moδ+. The active hydrogen was adsorbed on the nickel sites, and the molybdenum species were responsible for eliminating the oxygen in aromatic oxygenates.

Catalytic Hydropyrolysis of Lignin for the Preparation of Cyclic Hydrocarbon-Based Biofuels

The demand for biomass utilization is increasing because of the depletion of fossil resources that are non-renewable in nature. Lignin is the second most renewable organic carbon source, but currently it has limited scope for application in the chemical and fuel industries. Lignin is a side product of the paper and pulp, sugar, and 2G bioethanol industries. Many research groups are working on the value-addition of lignin. Among the lignin depolymerization methods, catalytic hydropyrolysis is gaining attention and is playing a crucial role in developing biorefinery. The hydropyrolysis of lignin was conducted at a higher temperature in the presence of H2. The hydropyrolysis of lignin results in the selective formation of non-oxygenated cyclic hydrocarbons in a shorter reaction time. It is possible to use the cyclic hydrocarbons directly as a fuel or they can be blended with conventional gasoline. This review focuses on the prior art of pyrolysis and hydropyrolysis of lignin. Possible products of lignin hydropyrolysis and suitable synthetic routes to obtain non-oxygenated cyclic hydrocarbons are also discussed. The influence of various process parameters, such as type of reactor, metal catalyst, nature of catalytic supports, reaction temperature, and H2 pressure are discussed with regard to the hydropyrolysis of lignin to achieve good selectivity of cyclic hydrocarbons.

Molecular record of the SPICE event in well YD2, Tarim Basin: Insights from catalytic hydropyrolysis of kerogens

The Steptoean Positive Carbon Isotope Excursion (SPICE) event is extensively documented in globally distributed carbonate and organic-rich successions of slope and platform environments during the late Cambrian (ca. 497–494 Ma). Despite numerous studies, its regional manifestation remains controversial because of the major uncertainty of the redox conditions in sedimentary paleoenvironments and its effect on the changes in the biota. Biogeochemical processes that occurred during the SPICE event are important for assessing whether the excursion is associated with the co-evolution of organisms and environments. In this study, we investigated the changes in plankton and paleoenvironment at the molecular level by combining kerogen elemental analysis, catalytic hydropyrolysis (HyPy), and gas chromatography-mass spectrometry (GC-MS) analyses of saturates and aromatics with published carbon isotopic data. The three fluorene series, gammacerane/C30hopane (G/C30H) and pristine/phytane (Pr/Ph) ratios demonstrated that the shallow shelf seawater changed significantly from relatively reducing to oxidizing and back to reducing conditions during the SPICE interval coupled with a regression-transgression cycle. The phytoplankton during the rise of the SPICE were mainly organic-walled, such as cyanobacteria, various acritarchs, and algae, as evidenced by terpanes, hopanes, and steranes. Significant decreases in phytoplankton diversity and abundance coincided with the peak of the SPICE, corresponding to the most oxidized and hypersaline periods during the SPICE event in the eastern Tarim Basin. Plankton assemblages diversified significantly with increasing living space due to the rise of sea-level during the post-SPICE period. Therefore, this study supports the idea that plankton groups changed dramatically with the environment, and its revolution followed the SPICE into the Great Ordovician Biodiversification Event.

Catalytic hydropyrolysis of lignocellulosic biomass to BTX and biofuels over zeolite beta based catalysts

Catalytic hydropyrolysis of eucalyptus leaves was investigated in a batch reactor over four catalysts (H-BEA, Ni/BEA, Ni/Fe-BEA and Fe/BEA). HBEA catalyst exhibited a higher monoaromatic hydrocarbons (MAHs) selectivity compared to non-catalytic pyrolysis. However, the selectivity to polyaromatic hydrocarbons (PAHs) was not significantly reduced by the addition of a protonic zeolite. The highest cycloalkanes selectivity (78.5%) was observed over Ni/BEA, owing to its high concentration of Ni sites as well as acid sites, facilitating the hydrogenation and ring-opening of polyaromatic hydrocarbons together with the hydrodeoxygenation of phenols. In contrast, the Ni/Fe-BEA exhibits the highest selectivity of MAHs, suggesting the Ni-Fe species facilitate the partial hydrogenation of PAHs and hydrogenolysis of phenols but restrict the further hydrogenation of aromatic monomers. Moreover, the reduction of CO to CH4 was restricted over Ni-Fe/BEA compared to Ni/BEA. A high selectivity of phenols and PAHs was detected over Fe/BEA due to the high oxophilicity but low hydrogenation activity of Fe species, hindering the hydrogenation of PAHs and HDO of phenols. The spent Ni/BEA and spent Ni/Fe-BEA catalysts exhibited a higher surface area and pore volume as well as lower mass of deposited carbon compared to spent HBEA and spent Fe/BEA catalysts, suggesting the catalyst deactivation was restricted by hydrogenation metal (Ni, Ni-Fe) and dissociated H species. Besides, high H2 pressure promoted the hydrogenation and ring-opening of polyaromatic hydrocarbons, and high reaction temperature hindered the hydrogenation of MAHs to cycloalkanes. The highest selectivity to MAHs (85.1%) with a 62% selectivity of BTEX was observed over Ni/Fe-BEA catalyst at 400 °C and an initial H2 pressure of 3.0 MPa.

Comparison of the Ediacaran and Cambrian petroleum systems in the Tianjingshan and the Micangshan uplifts, northern Sichuan Basin, China

Several different types of petroleum occurrences (including solid bitumens, oil sands, and oil seeps) are observed in various strata (e.g., the Ediacaran, Cambrian, Devonian, Permian, Triassic, and Jurassic strata) of the Tianjingshan and the Micangshan uplifts, northern Sichuan Basin, China. However, the sources of these petroleum occurrences are still in dispute, because of the severe biodegradation, strong thermal alteration, and multiple tectonic movements. At present, such uncertainty in the potential source rock systems has hindered oil and gas exploration in the study areas. In this study, methods including catalytic hydropyrolysis and trace elements analysis were introduced into the oil-source correlation study, to avoid the influence of biodegradation and/or thermal alteration. The results show that the petroleum shows that occur in the Cambrian-Jurassic strata of the Tianjingshan area are characterized by low maturity (equivalent vitrinite reflectance (EqVRo) < 1.0%), light organic carbon isotopic ratios (δ13Corg values ranging from −34.0‰ to −38.4‰), a predominance of C29-steranes, enrichment in V and Mo, and strong depletion in Bi elements. In contrast, the solid bitumens in the Ediacaran Dengying Formation in the Micangshan area have high maturity (EqVRo > 2.0%), slightly heavier δ13Corg values ranging from −27.5‰ to −36.0‰, a predominance of C27-steranes, weak enrichment in Mo and strong depletion in Rb and Bi elements. In addition, the Ediacaran and the Lower Cambrian source rocks can be discriminated by the bound sterane distributions, trace element concentrations, and bulk δ13Corg values. Further oil-source correlation indicates that the petroleum shows in the Cambrian-Jurassic strata in the Tianjingshan area were dominantly derived from the Lower Cambrian Qiongzhusi Formation, while those in the Ediacaran Dengying Formation in the Micangshan area were mainly sourced from the Ediacaran Doushantuo Formation. Finally, the results of oil-source correlation, combined with the tectonic evolution history of the investigated areas further elucidate the occurrence and distribution of petroleum, which can assist in oil and gas exploration in the investigated uplifts and the adjacent areas.