Thermal Cracking Process Research Articles

A new insight into H-donor’s positive effect on thermal cracking process at molecular level

Thermal cracking reactions of vacuum residue (VR) at 420 ℃ with different reaction time were carried out to evaluate an industrial H-donor’s effect on thermal cracking process at molecular level. The mass distribution, conversion ratio, asphaltene and coke yields were analyzed to evaluate the changing rules. Aromatic structures of H-donor were analyzed and its typical structures were speculated, and the bond energy of those model compounds were calculated. It can be concluded that the >460℃ fractions from a refinery stream have abundant H-donors. From analyzing the structures of asphaltenes for the feed and products, it can be learned that H-donors not only can modify the asphaltene structures but also can improve the asphaltene solubility.

Study on thermal crack characteristics of granite in Shandong Province, China under different temperatures and heating/cooling treatments

The qualitative and quantitative analysis of crack initiation characteristics, extended procedure, and crack network morphology of rock under different temperatures and heating/cooling paths was conducted in order to delve deeper into the mechanism of thermal cracking, and the analytical perspectives mainly include microstructure, thermodynamics, and mineral crystal properties. Research results indicate that 200–300 °C and 600 °C are two obvious mutation points of water-cooled samples, while air-cooled samples show mutation points around 600 °C. The initiation positions of thermal cracking under all temperature paths are relatively similar, with intergranular crack located between particles at the edge of the sample or intercrystalline cracks in the middle of feldspar or quartz aggregates. Slow heating and rapid cooling contribute to the complexity of the thermal crack network, and rapid heating can form larger sized thermal cracks. The process of thermal cracking can be divided into three stages: initiation of small cracks, joint development of main cracks and small cracks, and interconnection of cracks to form a network structure. The thermal cracking mechanism is attributed to differences in expansion and thermal conductivity among various crystals.

THERMAL TRANSFORMATIONS OF MALTENES AND OILS FROM HEAVY METHANE BASE CRUDES

The paper considers changes of composition of oils and maltenes during thermal cracking process. The oils and maltenes (mixture Oils+Resins) were isolated from crudes from two oil fields: Zyuzeevskoye (Republic of Tatarstan) and Zuunbayanskoye (Mongolia). Both crudes relate to methane type, but differ by content of saturated, aromatic hydrocarbons, resins, asphaltenes and sulfur. Cracking of oils and (O+R) mixtures was carried out at 450 °С for 120 min in isothermal mode. Data on the mass balance of process, composition of gaseous and liquid cracking products were obtained. It was shown the С1-С5 hydrocarbons are predominate in the composition of gaseous cracking products of oils and (O+R) mixtures. Independent of cracking object their content changes in a series: C1 > C2 > C3 > С4-С5. The dynamics of group hydrocarbon composition changes in thermolysates was studied. It was shown the thermal transformations of hydrocarbons steer in the direction of destruction reactions during cracking of oils with high content of saturated hydrocarbons, as it indicated by gaseous products yield. Condensation reactions are dominated during cracking of oils, in composition of which aromatic hydrocarbons are prevail. It was shown the addition of resins into the complex multicomponent mixture of hydrocarbons leads to directivity change of cracking free radical reaction behavior. Differences in structural-group characteristics of average resins molecules reflect not only on the yield of solid and gaseous cracking products of (O+R) mixture, but also affect on the directivity of hydrocarbons thermal transformations. Moreover it is impossible to exclude the effect of differences in the content of saturated and aromatic hydrocarbons in the composition of oils on the components thermal transformations during cracking process of (O+R) mixtures. For citation: Voronetskaya N.G., Pevneva G.S. Thermal transformations of maltenes and oils from heavy methane base crudes. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 8. P. 59-67. DOI: 10.6060/ivkkt.20246708.4t.

Utilization of waste tires in the process of thermal cracking of vacuum gas oil

The process of thermal cracking of vacuum gas oil (VGO) with the addition of 10% tire crumb at a temperature of 500 °C and feed rate of 1 h- ¹ was studied. In the course of the study experiments were carried out, which showed that the introduction of tire crumb into the composition of VG promotes the acceleration of conversion of the heavy fraction of VG. Addition of 10% of tire crumb has a positive effect on the cracking process, which is expressed in the increase in the yield of diesel fraction by weight by 2%. Analysis of the material balance of the thermal cracking process of crushed tire crumb shows that under these conditions tire crumb was poorly subjected to thermal transformation. The yield of gasoline fraction and light gas oil fraction in the catalyst composition was only 1% and 7.4% by weight, respectively. The conversion of tire crumb into light fractions including gas oil reached 20.5%. Addition of 10% by weight of tire crumb to the composition of vacuum gas oil increases the yield of gasoline and diesel fractions (light gas oil fractions), while reducing the amount of heavy gas oil. The increase in the yield of diesel fraction is 4% by weight, and the total conversion of blended feedstock reaches 59.5%. Thus, the addition of tire crumb to the composition of vacuum gas oil practically does not affect the total conversion, but increases the yield of light gas oil. This allows us to conclude that the introduction of tire crumb contributes to a more efficient conversion of heavy fractions of vacuum gas oil. After hydrotreating process the obtained diesel and gasoline fractions can be successfully used as components of automotive fuels. Thus, the addition of tire crumb to the thermal cracking process of vacuum gas oil not only improves the conversion of heavy fractions, but also increases the yield of valuable products such as diesel fuel, which is important for the refining industry.

In Situ Combustion Characteristics of Heavy Oil in the Liaohe Oilfield at Different Temperatures

This study conducted in situ combustion oxidation experiments on crude oil from Block D within the Liaohe Oilfield, utilizing a kettle furnace low-pressure oxidation reaction method at various temperatures. The molecular composition of oxidation products was analyzed using gas chromatography–mass spectrometry (GC–MS) and high-resolution mass spectrometry. The results reveal that the molecular composition of the products remains relatively stable up to 300 °C, exhibiting a slight increase in C13-C30 alkanes. The ratio of the peak area for C21 to bisnorhopane is 0.082. From 300 °C to 450 °C, compounds with long alkyl chains gradually undergo thermal cracking, resulting in a significant increase in the production of alkanes within the C10–C30 range. The concentration of saturated hydrocarbons produced through thermal cracking reaches its maximum at a temperature of 400 °C. The most abundant peak of n-alkane is observed at C21, with a quantified ratio of peak area for C21 to bisnorhopane at 6.5, indicating a two-order magnitude increase compared to crude oil. From 500 °C to 600 °C, compounds undergo more profound thermal cracking and condensation processes. The predominant hydrocarbons consist of aromatic molecules containing two to six rings substituted with short side chains. The double bond equivalent (DBE) values of carbazoles and carboxylic acids are determined as 30 and 25, respectively. At 600 °C, the peak area ratio of naphthalene to biodecane is 300, indicating a remarkable increase of five orders of magnitude compared to the crude oil. The present study elucidates the correlation between the characteristics of combustion components in crude oil and the corresponding combustion temperature. Primary cracking reactions within crude oil are promoted effectively when keeping the combustion zone at 350 °C and 450 °C. This process significantly reduces the viscosity of heavy oil and enhances its fluidity.

Converting of Waste Crude Oil of East Baghdad Oil Field into Light Hydrocarbons Using Thermal Cracking Technology

East Baghdad oil field produces a lot of quantities of waste crude oil due to drilling and production processes activities. This waste is caused a negative impact on the environment and human health. In the present investigation, the collected waste crude oil of API= 13 was converted into light hydrocarbons via a thermal cracking reaction. The thermal cracking process was achieved in a batch reactor at temperatures ranging between 350-450°C in absence of oxygen. At each temperature, the reaction pressures varied between (1-6) kg/cm2. Moreover, a continuous stirring of the reaction mixture inside the reactor was continued during the course of the thermal cracking process at a velocity of 96 rpm. The best yield of produced liquid hydrocarbon, gases, and coke at optimum conditions was 77.56 wt.%, 9.3 wt.%, and 13.14 wt.%, respectively. Actually, this process regards cheap, and simple with a high rate of liquid hydrocarbon production as well as environmentally beneficial.

Thermo-mechanical coupled peridynamics simulation of concrete failure under fire scenarios

A coupled thermo-mechanical bond-based peridynamical (PD) method is developed to simulate thermal cracking processes in concrete. Based on the bond-based PD heat conduction and motion equations, the PD differential operator (PDDO) is used to express the classical computational fluid dynamics basic equations in a non-local integral form, establishing a PD model for the thermo-mechanical coupling problems. In this model, concrete is considered a heterogeneous material composed of aggregates and mortar, with material parameters assumed to be temperature-dependent. The multi-rate explicit time integration scheme is proposed to overcome the multi-scale time problem in coupled thermo-mechanical systems. The model is applied to simulate the transient heat transfer problem of a homogeneous plate. The results show good agreement with the analytical solution, providing evidence for the correctness and accuracy of the proposed coupled numerical method. The damage behavior of the borehole heated concrete plate is analyzed, followed by the simulation of the damage to the concrete plate under a fire scenario. The numerical results accurately predict the temperature distribution within the heterogeneous concrete and the resulting material damage. This study provides new theoretical basis for the fire resistance design and high-temperature performance improvement of concrete materials and structures.

Syngas optimization and tar reduction via multistage catalytic gasification: Effects of catalyst pore, catalyzer stage, and temperature profile

Biomass stands out as a promising availability source of sustainable carbon energy due to its low pollution profile and versatile applications. This study investigates the multistage catalytic gasification (MCG) of coconut shells, employing thermal and catalytic cracking processes in a two-step gasification approach. Local source catalysts, including dolomite, kaolin, and zeolite, were utilized as eco-friendly additives at temperatures ranging from 200 to 300 °C. Zeolite emerged as the most effective catalyst, producing the highest energy content at 6.21 MJ/kg. Conversely, kaolin resulted in higher CO2 emissions. A blend of zeolite and kaolin achieved the highest energy content at 5.43 MJ/kg. However, the combined use of catalysts showed negligible improvements compared to individual catalysts. The study demonstrates that multistage catalytic gasification enhances syngas production and reduces tar content during the gasification of coconut shells. Optimal pyrolysis temperatures were identified within the 500–600 °C range. In conclusion, the introduction of multiple stages in the catalytic cracking process ensures a stable breakdown of hydrocarbon chains, promoting the exposure of gasification products to lighter compounds. Multistage catalytic gasification enhances oxygen supply for oxidation, thereby improving syngas production while mitigating tar and ash content.

A conceptual investigation for a novel CO2-self-supplied integrated reactor containing ethane thermal cracking and CLC processes

In recent years, numerous efforts have been made to enhance ethane thermal cracking performance, reduce environmental pollution, and save energy. In this study, the combination of the ethane thermal cracking and the chemical looping combustion (CLC) in a multi-tubular integrated reactor has been investigated. The suggested reactor consists of two concentric cylinders with some tubes embedded in the inner cylinder. The oxidation reaction of nickel as a suitable oxygen carrier is considered to be performed in the internal cylinder (air reactor). This reaction provides the essential thermal energy for reduction reaction in the external cylinder (fuel reactor) and the ethane thermal cracking process. Thus, this configuration leads to the elimination of thermal furnace in this process. Therefore, the environmental pollutants such as CO2 and NOx, as well as the operational costs, are significantly reduced. On the other hand, by this novel configuration, the ethylene and hydrogen production rates are improved in the ethane thermal cracking process. According to the results, the ethylene and hydrogen production yield increases by about 14% and 17%, respectively, compared to the conventional reactor of the ethane cracking process. The effects of design on the system performance have also been studied.

The pyrolysis of 4,4,8,10-tetramethyl decalin and the influence of molecular structures on oil thermal cracking: A ReaxFF molecular dynamics simulation and DFT study

The molecular structure of different hydrocarbons in crude oil has a significant effect on the thermal cracking mechanism. This study delves into the thermal cracking mechanism, pyrolysis process, and kinetics of 4,4,8,10-tetramethyl decalin (a representative bicyclic sesquiterpane in crude oil) using reactive molecular dynamics simulation (ReaxFF–MD) at the temperature range from 2000 K to 3000 K. Interestingly, the major intermediate products from thermal pyrolysis simulation align closely with the main ion fragments in the mass spectrometry of 4,4,8,10-tetramethyl decalin. The results can be directly used to analyze the pyrolysis mechanism. It reveals five reaction pathways implicated in the initial pyrolysis of 4,4,8,10-tetramethyl decalin: three demethylation reactions (more likely to occur) and two ring-opening reactions. By employing first-order kinetic analysis based on ReaxFF–MD simulations within the temperature range of 2000 K to 3000 K, the apparent activation energies for 4,4,8,10-tetramethyl decalin are calculated and compared with our prior simulation results for n-tetradecane. The initial pyrolysis of 4,4,8,10-tetramethyl decalin predominantly entails the cleavage of C–C bonds in both branched chain and carbon ring systems, resulting in the generation of methyl and high molecular weight ring-structured radicals. Conversely, the initial pyrolysis of n-tetradecane yields low molecular weight straight–chain radicals by cleaving C–C bonds except for the terminal position. This implies that the bicyclic sesquiterpane 4,4,8,10-tetramethyl decalin serves as the favorable precursor for producing methane (CH4) and liquid hydrocarbons (C6–C13) during the primary formation stage of light oil. With an equivalent number of carbon atoms, n-tetradecane serves as the preferred precursor for generating wet gases (C2–C5) at the initial formation stage of wet gases. The insights derived from the ReaxFF–MD simulation offer valuable perspectives for comprehending the process of thermal cracking in crude oil under geological conditions.

INCREASING THE EXTRACTION OF VACUUM GAS OIL AT THE ELOU-AVT UNIT

The ELOU-AVT unit is part of a large oil refining complex. This unit is designed for primary processing of oils from various fields, as well as their mixtures. Refining is carried out in order to separate oil into separate fractions (gasoline, kerosene, diesel fuel, fuel oil), which are used as raw materials for secondary oil refining at other units. On the territory of modern refineries, in order to increase the depth of processing of petroleum feedstock, in most cases the following technological units are used: – The isomerization unit is designed for the production of low-boiling high-octane isomerizate used as a component of unleaded motor gasolines. For the production of a low-boiling high-octane component, the plant uses the process of low-temperature isomerization of C5-C6 normal paraffins. – The distillate hydrotreating unit is designed to produce high-quality diesel fuel with low sulfur and nitrogen content, high cetane number, and improved low-temperature properties. – The sulfur production unit is designed to produce solid commercial sulfur by the oxidative conversion of hydrogen sulfide into elemental sulfur. The delayed coking unit is designed to process heavy oil residues (straight-run tar) into lighter gaseous, liquid products and petroleum coke. The process of thermal cracking is the basis for the processing of tar. – The catalytic reformer with preliminary hydrotreatment is designed for the processing of gasoline fractions of oil in order to obtain high-quality gasolines and aromatic hydrocarbons, as well as hydrogen-containing gas (HCG), which is widely used both in petrochemistry and in such oil refining processes as: hydrotreating, hydrocracking, isomerization, etc. Oil refining is a multi-stage process of physical and chemical processing of crude oil, which results in the production of a complex of petroleum products. Industrial primary distillation units are divided into atmospheric (AT), vacuum (VT) and combined (for example, AVT, CDU-AVT, etc.). It is impossible to obtain a single marketable oil product from crude oil directly by one process (with the exception of gases), all of them are obtained by sequential processing at several installations. Keywords: ELOU-AVT machine, distillate hydrotreating unit, Oil refining, multi-stage process, primary distillation units

Deep Learning Aided Multi-Objective Optimization and Multi-Criteria Decision Making in Thermal Cracking Process for Olefines Production

BackgroundMultilayer perceptron (MLP) aided multi-objective particle swarm optimization algorithm (MOPSO) is employed in the present article to optimize the liquefied petroleum gas (LPG) thermal cracking process. This new approach significantly accelerated the multi-objective optimization (MOO), which can now be completed within one minute compared to the average of two days required by the conventional approach. MethodsMOO generates a set of equally good Pareto-optimal solutions, which are then ranked using a combination of a weighting method and five multi-criteria decision making (MCDM) methods. The final selection of a single solution for implementation is based on majority voting and the similarity of the recommended solutions from the MCDM methods. Significant FindingsThe deep learning (DL) aided MOO and MCDM approach provides valuable insights into the trade-offs between conflicting objectives and a more comprehensive understanding of the relationships between them. Furthermore, this approach also allows for a deeper understanding of the impact of decision variables on the objectives, enabling practitioners to make more informed, data-driven decisions in the thermal cracking process.

On the influence of low octane gasoline and biodiesel on diesel engine operating characteristics

Biodiesel is a promising alternative fuel, but it has drawbacks. This research aims to diminish the NOx dilemma for diesel and biodiesel by utilizing straight-run naphtha as an additive. It has a low carbon footprint of production from light distilled crude oil without any requirement for the thermal cracking process. The diesel was blended with naphtha at percentages of 5%, 10%, and 15% that abbreviated by N5, N10, and N15, respectively. The biodiesel/diesel blend was mixed with the same naphtha concentrations forming the blends B30N5, B30N10, and B30N15, respectively. Experiments were applied on a single-cylinder engine at 2,000 rpm and different loads. The findings revealed that N15 declined the brake specific fuel consumption (bsfc) at most loads relative to neat diesel. Contrarily, biodiesel blends reflected a spiking trend of bsfc at tested loads. Notably, the NOx emissions declined with N15 blend at high loads relative to neat diesel. The blends B30N15 and B30N10 reduced NOx at high loads compared to the diesel/biodiesel blend. The straight-run naphtha was found to be a promising additive because the balanced composition of the iso-paraffins and n-paraffins. Hence, it dominated the ignition tendency and reduced NOx emissions due to its cooling effect.

Liquid fuel production from high density polyethylene plastic waste

This research aims to determine the effect of heat exchanger diameter variations on the volume and physical properties of fuel derived from plastic waste. The plastic waste is converted using the thermal cracking method, which involves heating the raw material without oxygen. This process produces charcoal and oil from the gas condensation in the heat exchanger. The type of plastic used is High-Density Polyethylene (HDPE) waste. The variations of heat exchanger diameter used are 1/2inch, 3/4 inch, and 1 inch. The physical properties investigated include density, viscosity, and heating value. From the test results, it was found that density of the oil fuel produced from plastic waste decreased with increasing heat exchanger diameter. However, the volume and heating value of the fuel produced increased. Generally, the physical properties of plastic pyrolysis oil produced from the thermal cracking process of plastic waste resemble those of gasoline

The mechanism of ethanol blending on the variation of chemical heat sink in n-decane thermal cracking process

The cracking of on-board hydrocarbon fuels is a strong endothermic reaction and can provide an additional chemical heat sink in the cooling process of the hypersonic vehicle. However, the cooling capacity of current hydrocarbon fuels can hardly meet the cooling requirements of the hypersonic vehicle at higher flight speeds. Blending ethanol is an effective method to improve the chemical heat sink of hydrocarbon fuels, but the mechanism of ethanol on chemical heat sink is unclear. In this study, n-decane was selected as a model compound of hydrocarbon fuels to investigate the physical and chemical effect of ethanol on the chemical heat sink of n-decane cracking by analyzing the chemical reactions involved through experimental study and chemical dynamic simulation. The results indicate that there is an optimum ethanol blend ratio to achieve the maximum chemical heat sink. The carbon monoxide methanation reaction which is an exothermic reaction can deteriorate endothermic process at 300–375 °C. With ethanol blending ratio above 20 wt%, ethanol vaporization deteriorates chemical heat sink by reducing the residence time in the temperature range of 225–250 °C. Pressure can suppress the reduction of residence time caused by ethanol evaporation and also suppress the positive reaction of ethanol cracking. The kinetic model of ethanol and n-decane mixture cracking was established. The calculated results verify that ethanol cracking (C2H5OH=CO+CH4+H2) and methane cracking (CH4=C+2H2) are dominant reactions in ethanol-assisted n-decane thermal cracking below 475 °C.

Evaluation of the Potential of Ethyl Esterification Reaction Catalyzed by Enzyme to Improve the Quality of Bio-Oil

Biomass has been investigated in recent years as an alternative source for fuel production. The use of triglyceride biomass is highlighted and, from the thermal cracking process, solid, liquid and gaseous products with energetic potential are generated. The liquid product, called bio-oil, has characteristics similar those of fossil fuels. Its composition is mainly based on hydrocarbons and carboxylic acids, and the second group generates a limiting characteristic in its processing, refining and use as fuel, increasing the acidity of bio-oil. In this work, bio-oil produced from commercial soybean oil was used in a thermal cracking process at 525ºC. The objective was to carry out ethyl esterification reactions via enzymatic catalysis in order to reduce the acidity index of the crude bio-oil. All reactions were carried out at 40ºC to avoid enzyme deactivation and different conditions of type and amount of catalyst, alcohol mass ratio and reaction time were evaluated. The best result was obtained after 6 hours of reaction with 60% acidity reduction, using Novozym 435 lipase as a catalyst at a concentration of 5% in relation to the substrate mass and 1:3 mass ratio.

Numerical analysis of hydro-thermal fracturing in saturated rocks by considering material anisotropy and micro-structural heterogeneity

This study is devoted to numerical modeling of cracking process induced by temperature change in saturated porous rocks in the context of geological disposal of radioactive waste. Effects of material anisotropy and heterogeneity are taken into account. The macroscopic elastic properties are determined from two steps of homogenization by considering pores and mineral inclusions at two different scales. An extended phase-field model is proposed to describe the initiation and propagation of localized cracks. Two damage variables are introduced to conveniently represent both tensile and shear cracks. New damage evolution criteria are defined by incorporating the pore pressure effect. Three application examples are presented. By assuming a random distribution of pores and inclusions, the efficiency of the proposed model for capturing the progressive cracking process is first verified in a triaxial compression test. The thermal cracking process in an anisotropic and heterogeneous sample is then investigated. The respective influences of elastic anisotropy and spatial variability of pores and inclusions are outlined. Finally, the proposed model is applied to a series of real laboratory thermal cracking tests. Both hydromechanical responses and cracking evolution patterns are investigated. Numerical results are compared with experimental measurements. The main mechanisms involved in the thermal cracking process are highlighted.

Molecular transformation of heavy oil during slurry phase hydrocracking process: A comparison between thermal cracking and hydrocracking

To systematically investigate the reaction mechanism of heavy oil in the slurry phase hydrocracking process, comparative experiments of thermal cracking and slurry phase hydrocracking of a residual oil were carried out. The molecular composition of sulfur and nitrogen compounds in the feedstock and their products was comprehensively characterized by gas chromatography and electrospray ionization Orbitrap mass spectrometry. The participation of hydrogen makes the apparent cracking rate in hydrocracking process significantly lower than that in the thermal cracking process, leading to a more controllable cracking degree and higher liquid yield. Nitrogen- and sulfur-containing aromatics with high molecular condensation degree are the key refractory heteroatoms because of large steric hindrance. Aromatics with ring number over 4 have high saturation reactivity, as well as the exposed five-membered heteroaromatic rings. The mutual influence of cracking, aromatic saturation, and hydrodeheteroatom during hydrocracking were also discussed according to bulk properties and molecular composition. The results deepen the understanding of the complex reaction network and mechanism of heavy oil hydrocracking process from both thermal reaction and hydrogenation perspectives, which will be instructive for the catalyst design and the process optimization.

Molecular mechanism of metamorphic alteration on traces of early life in banded iron formations

It is well-known that multi-stage metamorphism can result in the alteration of indigenous biological molecules, limiting our understanding of early life on Earth. However, the physiochemical mechanisms involved in these processes are still poorly understood. In this study, we present petrographic observations and micro- to nano-geochemical investigations on the carbonaceous matter (CM) in representative Neoarchean banded iron formations (BIFs) from North China, which have undergone significant alteration during lower amphibolite-facies prograde metamorphism, and subsequent retrograde alteration. The CM is in paragenetic equilibrium with prograde mineral phases, and is often associated with apatite that occurs in Fe-rich bands parallel to layering. This implies that the CM is most likely inherited from syn-depositional biomass, as confirmed by the nanoscale infrared spectroscopy, which shows the presence of CC, CH, and CN/NH bonds. Raman spectroscopic analyses reveal that the maximum metamorphic temperature of CM is 479 ± 50°C, which is consistent with the metamorphic peak conditions of the host BIFs from petrographic constraints (i.e., garnet-bearing amphibolite-face metamorphism). The BIFs possess average bulk δ13Corg values of −20.0 ± 0.9‰ (1σ) and δ13Ccarb values of −12.9 ± 1.8‰ (1σ), further indicating syngenetic biomass graphitization during prograde metamorphism. This thermal cracking process may have released gaseous hydrocarbons, as shown by secondary CH4 fluid inclusions in quartz. We further use quantum mechanical simulations to constrain dissociative tendencies for functional groups (CC, CH, CO, and CN) of original organic molecules to assess the stability of organic chemical bonds during prograde metamorphism (0–600°C, 0–15 kbar). The relatively high thermal durability of CH and the armoring effects of primary organic-phyllosilicate complexes may account for CH preservation in BIFs. Furthermore, the electron microscopy combined with elemental analysis reveals widespread nano-chlorite infiltration into CM during retrograde metamorphism (i.e., partial replacement of garnet by chlorite). The pervasive CM alteration is likely responsible for the absence of CO bonds, where nanopore-scale reactions might have played a key role. Altogether, we suggest that multi-stage metamorphic processes, involving mineral-organic reactions and nanoscale interface interactions, may have governed the preservation of ancient biosignatures in BIFs. Our findings highlight the importance of evaluating metamorphic effects when using molecular signals to reconstruct early life behaviors, and shed new light on the study of primordial microorganisms, particularly those found in iron-rich sediments on early Earth.

Potential of Pyrolytic Oil from Plastic Waste as an Alternative Fuel Through Thermal Cracking in Indonesia: A Mini Review to Fill the Gap of the Future Research

This article aims to review the potential and feasibility of pyrolytic oil from plastic waste (POPW) as a substitution fuel for conventional fossil fuels. Pyrolytic oil can be generated from plastic waste through the thermal cracking process. In addition to overcoming the global plastic waste problem, recovering plastic waste into alternative fuels can also reduce the consumption of fossil-based fuels. The research on POPW production and utilization of internal combustion engines (ICE) was reviewed and discussed to determine their potential and suitability for fuel substitution. Currently, plastic materials can be easily found in various product packaging, ranging from food and beverage packaging to shopping bags and appliances. When they are no longer utilized, this plastic becomes garbage and will be very harmful to humans and the environment. Therefore, it needs a correct way to proceed and minimize the impact caused by plastic waste. In fact, there are seven types of plastic waste in the polymer groups that must be handled via the pyrolysis process to avoid plastic pollution. literature survey, research on POPW via the pyrolysis process, and its usage is thoroughly found to be booming and growing very rapidly. Co-pyrolysis is known to be the most potential and suitable way to produce high-quality POPW, which is suitable to be used to fuel the ICE and also the stationary industrial engine.