Decant Oil Research Articles

Mesophase pitch-based high performance carbon fiber production using coal extracts from mild direct coal liquefaction

Mild direct coal liquefaction (autogenous pressure, no catalyst, no H2 gas) of Springfield coal in fluid catalytic cracking decant oil is shown to effectively produce coal extract precursors to spinnable mesophase pitch. This work demonstrates that the coal extract can be thermally treated to obtain mesophase pitch in a facile one-step process, bypassing the production of an intermediate isotropic pitch. Furthermore, the presence of 25 wt.% coal in the initial slurry can increase the yield to mesophase pitch nearly twofold and yield to carbon fiber by approximately 70%. The coal extract-derived mesophase pitch was melt-spun and heat treated to produce carbon fiber with graphitic texture, high modulus (>400 GPa) and tensile strength up to 943 MPa. Overall, this work demonstrates that coal can be effectively utilized to markedly amplify the mesophase pitch and carbon fiber yield from fluid catalytic cracking decant oil by relatively simple processing, while conserving utility as a precursor to high performance carbon fiber and potentially other high value graphitic products.

Production of Fuel Oil from Blends of Refinery Products for Powering Heat Exchanger

Fuel oil, also known as furnace oil is a fraction of crude oil obtained when distillation processing is carried out in the refinery. Due to the high viscous of the heavy fuel oil, that makes it difficult to be pump throughout the pipework of the power plant, it is necessary to produce a fuel oil that will meet up the required standard. The aim of this study was to produce fuel oil from the blend of refinery intermediate product which meet certain European fuel specifications outlined in the EN 590:2009 standard alongside NMDPRA Standards. The blending stocks obtained from the Warri Refinery and Petrochemical Company (WRPC) were first filtered to remove some particulate impurities before they were analyzed to determine their properties after which, they were introduced into a mixed-tank that has an agitator connected and the blending was done using the blending ratio obtained from literature. The fuel oil produced was eventually analyzed for properties such as: Specific Gravity, API Gravity, Density, Viscosity, Kinematic Viscosity, Moisture Content, Flash Point, Cloud Point, Pour Point and Sulphur content. The sample with a composition of 33.3% of Decant oil (DCO), 33.3% Heavy gas oil (HGO), 33.3% light cycle oil (LCO) produced fuel oil of specific gravity 0.916, API Gravity 22.95, Density 0.896, Viscosity 40, Kinematic viscosity 4.7, pour point -6.5 and flash point 109, The analysis of the fuel oil meet the standard for blended fuel oil, according to the ISO 8217:2017 Standard. The results confirmed that blending of decant oil with conventional petroleum diesel (heavy and light gas oil) has a highly significant effect on the properties of the resulting fuel blend. The results show that by increasing the heavy gas oil content of the blend, the flash point of the blend increases; while increasing the decant oil content of the blend results in a decrease in Cloud point. The results of the analysis of the produced fuel oil confirms that its properties fall within the acceptable range for Fuel Oil and can be used as fuel for fired heaters and furnaces of the refinery and other process plants.

Production of needle cokes via mild condition co-pyrolysis of FCC-DO and PFPE

The conventional needle coke production process suffers from high reaction temperature and pressure, and therefore, alternative approaches for needle coke production with low energy consumption should be developed. The co-pyrolysis process of FCC decant oil (FCC-DO) and perfluoropolyether (PFPE) was suggested to prepare needle cokes under mild reaction conditions in this work. The characteristics of green pitches and cokes from the co-pyrolysis process were evaluated with XRD, FT-IR, TGA, EA and polarized images to prove the effectiveness of the PFPE-aided reaction in accelerating polymerization. The mixture of FCC-DO and 10 wt% of PFPE was heated to 420, 430, 440, and 450 °C and 1 bar in continuous nitrogen flow, and needle cokes could be successfully derived at a temperature of 440 °C and atmospheric pressure with the addition of PFPE, which are significantly milder conditions compared with prior studies on needle coke production. The reaction mechanism of co-pyrolysis was suggested with radical-based reactions that emerged during the thermal decomposition of PFPE. Furthermore, the electrical and thermal properties of the carbonized needle cokes indicated the superior structural, thermal, and chemical characteristics of PFPE-assisted reaction-derived needle cokes; the needle cokes obtained from PFPE co-pyrolysis showed a 23.5 % reduced CTE value and 7.2 times higher electrical conductivity compared with cokes from pure FCC-DO. Effective needle coke production at a low temperature and pressure could be achieved with a PFPE-assisted co-pyrolysis reaction, and we believe that this study could contribute to a novel method for preparing needle cokes with low energy consumption and extending the applicability of needle cokes by supplying high-quality and low-price needle cokes.

The effect of boron trifluoride complex on the preparation of mesophase pitch from FCC decant oil fractions with different compositions and molecular structures

The boron trifluoride complex catalyst can effectively facilitate the development of anisotropic structures in FCC decant oil (FCC-DO) through cationic polymerization reaction. However, the fractions of FCC-DO with different boiling points possess different molecular compositions and aromatic nuclei configurations. In this study, FCC-DO is separated into light fraction, middle fraction, and heavy fraction by vacuum distillation. The different carbonization reaction pathways and reactivity were systematically investigated for three narrow fractions with no or 5 wt% addition of boron trifluoride complex catalyst. The results show that the heavy fraction is dominated by 4 and 5 plus ring aromatics with short side chains and methylene-bridged bonds. The catalyst showed excellent catalytic activity for the heavy fraction, the resulting product (MP-HF-5) possessing a softening point of 307 °C and 3.06 wt% methylene-bridged hydrogen at 95.3 wt% mesophase content. However, the catalyst slightly facilitated the development of anisotropic structures in the middle fraction (rich in 3 and 4 rings aromatics with naphthenic structures), which provided mesogen molecules during the FCC-DO carbonization reaction. Finally, the 1 ∼ 3 ring aromatics with long alkyl side chains are mainly present in the light fractions. The catalyst did not show obvious catalytic activity for the light fraction, in contrast, the oxygen-containing functional groups in the catalyst reacted with the aromatic molecule to form a disordered oxidative cross-linked structure, resulting in an almost completely isotropic structure of MP-LF-5.

Phase transition behavior and mesophase aging phenomenon during liquid-state carbonization of FCC decant oil

The FCC decant oil (FCC-DO), primarily comprising 2- to 5-ring aromatic hydrocarbons with short alkyl side-chains, is widely acknowledged as the optimal precursor for the production of spinnable mesophase pitch, thus achieving its high-value utilization. The preparation of spinnable mesophase pitch from FCC-DO faces the challenge associated with achieving both high mesophase content and low softening point. To address this challenge, the phase separation behavior of the isotropic matrix and the aging phenomenon of coexisting anisotropic phases are examined using high-temperature centrifugation and advanced analytical techniques. The phase transition behavior of isotropic matrix can be described by a multi-stage continuous self-assembly induced by polymerized reactions. And this dynamic assembly process is tightly related to “steric hinderance effect” and “solvent dispersion effect”, which are mainly affected by the configuration and size distribution of formed mesogens respectively. Meanwhile, the formed anisotropic phase gradually undergoes two-staged time-dependent aging behavior, leading to poor compatibility of sub-fractions and then deterioration of melt fluidity. The initial aging of the mesophase is characterized by an almost unchanged molecular weight distribution, but a transformation of molecular configuration from a semi-rigid skeleton to a rigid one. This transformation is caused by intramolecular condensation resulting from the removal of the α-CH3 shielded by adjacent aromatic rings and dehydrogenation of naphthenic rings. When the previously-formed anisotropic phase under the liquid-state carbonized conditions for a long time, the second-stage aging of mesophase is readily triggered through the elimination of the α-CH3 not shielded by adjacent aromatic rings. This gives rise to the intermolecular polymerization and a shift towards higher molecular weight. This study provides insights into the preparation of excellent melt-fluidity mesophase pitch by promoting the rapid transformation of the isotropic matrix before significant aging of the coexisting anisotropic phase.

Microstructural diversity and digestion yields of select bituminous and subbituminous coals as raw material candidates for carbon fiber precursor production

This work investigates the use of coals as raw materials for carbon fiber precursor production as a new alternative to coal utilization. Coal being a highly complex and heterogeneous material with different macerals and minerals complicates this task. Extensive microstructural characterization as well as preliminary digestion studies are performed on three bituminous coals (Herrin and Springfield from the Illinois Basin and the Blue Gem from the Central Appalachians) and one subbituminous coal from the Powder River Basin (Monarch), as raw material candidates. The subbituminous coal was richer in oxygen, lower in sulfur, and had a higher volatile matter yield. Microstructural investigations were performed using X-ray diffraction, X-ray/neutron computed tomography, scanning electron microscopy with energy dispersive spectroscopy, and petrology. Mild solvent extraction studies were conducted using creosote and decant oil as solvents in microreactors. The extraction yield was sensitive to temperature and time (350 to 450 °C between 30 and 120 mins.) for both creosote and decant oil digestions. While the Blue Gem coal had more desirable microstructural properties with less mineral content and cleaner macerals, it had the lowest coal conversion to quinoline soluble ‘liquid’ (of the bituminous coals). The lower coal conversion yield was hypothesized to be connected to the lack of FeS2 which could act as a catalyst when Fe is liberated from the structure under solvent extraction conditions. The Herrin and Springfield coals revealed similar microstructures and coal conversion efficiencies (higher than Blue Gem). These coals were the most promising candidates for further examination from this first approximations study. The subbituminous Monarch coal, however, was deemed less suitable due to poor coal conversion and less desirable microstructures. Additionally, the presented results with combined microstructural data from multiple length scales established a framework necessary for a first approximations study in this new coal utilization approach.

Mesophase pitch production from fluorine-pretreated FCC decant oil

• Effect of fluorine treatment over FCC-DO for mesophase formation firstly suggested. • Reaction mechanism of mesophase formation by fluorination was suggested. • Fluorine promoted radical polymerization of FCC-DO to form heavy mesophase nuclei. • The amount of hydrogen donating species also increased after the fluorination. • Pitch from fluorinated DO had higher mesophase yield than pitch from pristine DO. Petroleum residue oil-based mesophase pitch production suffers from its low yield of mesophase. There have been continuous efforts, such as catalyst-assisted reactions and multistep heat treatments, to produce high-purity mesophase pitch. However, most of these techniques have difficulties with the processability. In this study, we suggest a novel fluorine pretreatment of fluid catalytic cracking (FCC) decant oil for mesophase pitch (MP) production. The effects of fluorine pretreatment on FCC decant oil were evaluated with mass spectrometry (MS) and their hydrogen donating ability. Subsequently, the MPs from pristine pitches with fluorine pretreatment were intensively compared in terms of structural, thermal, and chemical characteristics. From these results, it was found that fluorine pretreatment helps mesophase formation by catalytic radical polymerization but does not cause coking and does not require posttreatment. It was found that the fluorination method can also provide an effective method for generating MP by increasing the hydrogen donating ability (HDA) fraction. We believe that the results of this work could inspire new insights into MP production.

Effects of olefinic compounds on the thermal transformation for FCC slurry oil: Evolution pattern and mechanism

FCC decant oil was always used as the raw material for the preparation of high-value-added carbonaceous materials. There is little disagreement that the free radical mechanism induces thermal polymerization reactions between reactant molecules and intermediate species, which leads to the formation of carbonaceous mesophase in the early stage of carbonization. Olefinic hydrocarbons were recently found to be widely distributed in FCC decant oil in our previous research, and these chemically active compounds usually possess weak π-bonds in molecules and thus potentially form free radicals easily, which may impact the carbonization performance dramatically. This research investigated the effects of olefinic compounds on the preparation of needle coke from FCC decant oil, as well as the corresponding mechanism in depth combined with the evolution pattern of the intermediate species during liquid carbonization. ESR analyses were adopted to evaluate the variation of the concentration of stable free radicals. Stable free radical concentration varied greatly in diverse polymerizing systems along with the carbonization process. Olefin showed a significant effect on the stable free radical concentration during carbonization. The stable free radical concentration of the polymerizing system derived from FCC decant oil was 3.32 × 1020 spins/g when the reaction time was 4 h. But with 3 wt% addition of 2-vinylnaphthalene and squalene in FCC decant oil, the stable free radical concentration increased to 2.14 × 1021 spins/g and 1.33 × 1021 spins/g, respectively, with the same reaction time. Meanwhile, the olefins conjugated with aromatic rings shown more obvious effect on the generation of free radicals. Olefinic compounds can lead to a high generation rate of free radicals and significantly high stable free radical concentration in the polymerizing system which then promote the formation of disordered carbon materials. Besides, plenty of fine particles appeared between mesophase spheres with the addition of olefinic hydrocarbons, and then impeded the coalescence between mesophase spheres. Effect mechanism for olefin on the development of carbonaceous mesophase was proposed accordingly. In sum, the content of olefinic compounds in raw materials should be limited for reaching the requirements of the synthesis of carbon materials with superior structures, in which the content of olefinic compounds should be less than 1 wt% at least based on the research in this paper.

Influence of boron trifluoride complex addition on structure and composition of mesophase pitch from FCC decant oil via two-stage thermotreatment

In order to optimize the molecular structure and composition distribution of mesophase pitch, the two-stage thermotreatment process preparation using boron trifluoride ethyl valerate complex as catalyst was investigated. During the two-stage thermotreatment, the cationic polymerization initiated by catalytic polycondensation made carbonaceous microcrystalline molecules contain more semi-rigid structures, while parts of alkyl side chains and naphthenic structures were retained. Subsequently, the mesophase pitch was rapidly induced to form by removing non-mesogens and enriching sufficient concentrations of mesogens in the vacuum polycondensation stage. The results showed that the two-stage thermotreatment process could change the chemical structure of the aromatic nucleus and obtain a suitable softening point (283 °C) at 100% anisotropic content. The mesophase pitch with 5 wt% catalyst addition (MP-5) had high content of methylene structure (HF = 3.18 wt%), naphthenic structure (HN = 3.45 wt%) and fusible/soluble TI-PS sub-fraction (28.07 wt%). In addition, MP-5 also possessed high aromaticity (fa = 0.90) and stacking order (Lc = 37.48 Å, n = 11.70). Unfortunately, an increase in the oxygen-containing groups was accompanied when the catalyst content reached to 10 wt%, which disrupted the aromatic lamellae parallel stacking structure of the mesophase pitch due to steric hindrance, resulting in more isotropic structures in the product.

Co-carbonization of ethylene tar and fluid catalytic cracking decant oil: Development of high-quality needle coke feedstock

In this study, ethylene tar (ET) and refined ethylene tar (ETR) were co-carbonized with fluid catalytic cracking decant oil (DO) to prepare needle coke. The compositions and functional group changes of the blended feedstocks were revealed by Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance. Besides, the carbonization behavior of feedstocks was determined in terms of coke optical observation, carbonized gas composition, and escape rates. The morphology and performance of needle coke were evaluated by scanning electron microscopy and coefficient of thermal expansion. The results showed that the blending of DO to the feedstocks increases the H/C ratio and the content of alkyl and naphthenic structures, which improves the growth and development of the mesophase. However, the coke derived from co-carbonization of ET and DO exhibits a clear separation interface between different optical textures. Further investigation revealed that a large amount of asphaltenes in ET polymerized rapidly into mosaic texture, which hardens prematurely and cannot coalesce with the domain texture subsequently generated by DO. The compatibility of blending ETR and DO for co-carbonization improves significantly after ET is refined to remove asphaltenes. In addition, sufficient gas flow derived from DO promotes the optical microstructure of the resultant cokes by a transition from domain texture into acicular flow type. The synergistic effects between ETR and DO result in the actual CTE and yield of needle coke being lower than the theoretical ones. The CTE of NC-ETRDO50 is lowered to 1.62 × 10-6/°C, being almost the same as that of NC-DO, and the production growth of NC-ETRDO50 is even higher by 7.32% compared with that of NC-DO. Therefore, high-quality needle coke with high production was prepared from low-cost heavy oils.

Effects of decompressing carbonization on the preparation of needle coke from FCC decant oil

More efficient treatments of FCC decant oil (FDO) were developed to convert this common by-product in refineries to high-value-added carbonaceous materials, such as needle coke. The performance of the produced needle coke was determined by the properties of raw materials and the carbonization process based on the theories of carbonaceous mesophase. The preparation of needle coke can generally be divided into two stages before calcination and graphitization: liquid carbonization and solidification stage. Pressure in both stages, especially the pressure in the solidification stage, showed great effects on the properties of the products. The microstructure of semi-coke can hardly be the preferred needle structure with carbonization without decompressing operation, although the raw material satisfies the preparation requirement of needle coke. A new method for evaluating the order degree of microstructure (ODM) of semi-cokes was developed, enabling semi-cokes with preferable axial orientation to be further efficiently distinguished. The ODM value can also be used as an index to evaluate whether a semi-coke can be used as a precursor for further preparation of high-quality needle coke. The evolution of product gases can provide external force to the orientation of mesophase into the preferred needle structure in the product. This improvement can be achieved through decompressing operations in the second stage of carbonization and optimized when the pressure is at 0.5 MPa.

Preparation of mesocarbon microbeads as anode material for lithium-ion battery by co‑carbonization of FCC decant oil and conductive carbon black

Low yield and unremarkable electrochemical performance of MCMB prepared from conventional thermal polymerization are inevitable, which limits its large-scale application as anode material for lithium-ion batteries. Hence, in this work, MCMBs were prepared by co‑carbonization of low-valued FCC decant oil and conductive carbon black (CCB). CCB can enhance the nucleation, inhibit the growth of the mesophase spheres and adhere on the surface of spheres, thereby increasing the yields (38.9 wt%), influencing the microstructure and subsequent electrochemical performance of MCMB. The MCMBs prepared by doping with 3 wt% CCB exhibited a small particle size (15.0 μm) and moderate structural disorder degree with wide interlayer spacing (AD3/Aall = 18.15%, d002 = 3.5342 Å), which shortened the transport pathway of Li+ inside the microbeads. Besides, chain-like conductive carbon black connected to the surface of the MCMBs, forming a continuous and developed conductive network, which was benefit for increasing of electron conduction and enhancing the Li+ transport rate outside the microbead. Such MCMB delivered the superior long-term cyclability with specific capacity of 394.5 mAh g−1 at 0.5 A g−1 (over 400 cycles) and presented a high-rate capability with reversible capacity of 276.0 mAh g−1 at an ultra-high current density of 3 A g−1.

The effect of composition change and allocation in raw material on the carbonaceous structural evolution during calcination process

To investigate the effect of calcination process on the characteristics of different carbonaceous structures, decant oil (DO) and low-temperature coal tar (LCT) were selected as materials to refine and blend to prepare the green cokes with different microstructures, and the influence of calcination on the structural evolution of green cokes with different orientation and planarity was studied. It is concluded that the nitrogen content of calcined needle coke decreased to a relatively low value at the calcination temperature of 1300℃ and the removal of QI decreased the sulfur content in calcined cokes. Calcination process would further promote the accumulation of aromatic lamellae on the original basis. The abundant QI in LCT led to the formation of mosaic structures in green coke stage and calcination aggravated the poor planarity of aromatic sheets of mosaic texture. The refining process and blend of raw materials significantly enhanced the proportion of key components and calcination improved the extendability and planarity of graphitic aromatic sheets with the increase of Tri-Ar and Tetra-Ar. In addition, calcination further optimized the aromatic lamellae of acicular domain texture with good planarity and structural orientation, and DO-CNC obtained the highest stacking parameters (Lc = 3.55 nm; N = 11.30; d002 = 3.445 Å).

Study on the evolution of oxygenated structures in low-temperature coal tar during the preparation of needle coke by co-carbonization

Low-temperature coal tar is rich in oxygenated compounds which are hard to remove and make a great influence on the quality of needle coke. Low-temperature coal tar (LTCT) and decant oil (DO) were used to co-carbonize to prepare needle coke by liquid phase carbonization, and the evolution of oxygenated structures in LTCT during the preparation of needle coke was investigated. In the early stage of carbonization process, the C–OH/C–O/C–O–C functional groups were mainly transformed into COO– groups. With the deepening of carbonization depth, the COO– functional groups gradually converted into CO functional groups. The enrichment of aromatics and the introduction of high aromaticity material further promoted the conversion of oxygenated structures and the oxygen-containing crosslinking behavior. Excessive aromatic molecules provided active sites and free radicals for polycondensation and dispersed the distribution of oxygenated cross-linked structures in the whole carbonaceous structures, thus resulting into a more ordered lamellar orientation. This study provided theoretical basis for weakening the influence of the oxygenated structures on the quality of needle coke by enhancing aromatic content during co-carbonization.

Simulation of an Industrial Carbon Black Reactor Using Collision Kinetics

Purpose: Objective of the work was to test efficacy of the proposed flame chemistry and collision kinetics for prediction of process parametres through determination of the effect of basic process parameters on yield (which includes but not limited to grade of carbon black produced).
 Methodology: The research methodology in this work was simulation of an industrial Carbon Black Reactor based on reaction kinetics from flame chemistry which assumes that primary particle formation and particle growth is strictly by collision of molecular nuclei with gas molecule as proposed by the collision theory. Decant oil from the Fluid Catalytic Cracking Unit (FCCU) of the Warri Refinery and Petrochemical Company Limited of Nigeria represented by naphthalene was used as feedstock in the simulation while methane gas is the fuel for combustion needed to attain the reaction temperature.
 Findings: Results showed an excellent quantitative prediction of trends by models. Qualitative predictions gave far higher parameter values, something easily attributable to the excessively high values of kinetic data used for model testing. 
 Recommendation: The simplifying assumptions of these models completely ignored microscopic phenomena such as interface mass and heat transfer and other similar processes. Consequently, the model can be improved upon by introducing some of these processes as identified.

Investigation of the Dependence of the Softening Temperature on the Content of Mesophase in Petroleum Pitches Obtained from Heavy Pyrolysis Resin and Decant Oil

Investigation of the Dependence of the Softening Temperature on the Content of Mesophase in Petroleum Pitches Obtained from Heavy Pyrolysis Resin and Decant Oil

Carbonization of mesocarbon microbeads prepared from mesophase pitch with different anisotropic contents and their application in lithium-ion batteries

To clarify the relationship between the chemical compositions of green mesocarbon microbeads (GMCMBs) and the electrochemical behavior of carbonized mesocarbon microbeads (CMCMBs) for lithium-ion batteries, GMCMBs were prepared by emulsifying mesophase pitch (MP) with various anisotropic contents derived from FCC decant oil. Subsequently, GMCMBs were carbonized at 1000 °C, and their electrochemical behaviors were investigated. It was found that the GMCMB prepared from MP with a high anisotropic content (98 vol%) exhibited highly ordered aromatic lamellae stacking (ID/IG = 0.68) and a high condensation degree (IOS = 0.268). Therefore, CMCMB-98 with a highly ordered structure (ID/IG = 1.01) and low porosity (SBET = 80 m2/g) was formed, resulting in a high initial coumbic efficiency (74.8%). In addition, the GMCMB prepared from MP with a low anisotropic content (12 vol%) had more alkyl side chains and light components (ICHS = 0.50 TS = 22.7 wt%). CMCMB-12 with high porosity (SBET = 390.65 m2/g) and disorder degree (ID/IG = 1.21) was produced after the carbonization process, leading to a high capacity and rapid solid-state diffusion speed of Li+. Hence, CMCMB-12 can deliver the highest reversible capacity (405 mAh g−1 at 500 mA g−1 over 200 cycles) and excellent rate performance.

Modified effect on properties of mesophase pitch prepared from various two-stage thermotreatments of FCC decant oil

The comparative study of different two-stage heat treatments was conducted to illustrate the modified effects on improving yield and spinnability of mesophase pitch. In such two-stage thermotreatments, a pressured condensation is employed to involve low-molecular-weight species into the formation of mesogens, thereby increasing pitch yields. Subsequently, vacuum polymerization could contribute to rapid development of mesophase and then reduce the residence time. The results indicate that the short duration could decrease occurrence of the intramolecular aromatization and intermolecular polymerization reactions that are readily induced by elimination of α-methyl and dehyroaromatization of naphthenic rings during the later stage of heat treatment. Consequently, the formed semi-rigid molecules in QS sub-fraction (i.e., fusible component) are seldom transformed into rigid ones mainly constituting QI sub-fraction (i.e., infusible component). Ultimately, sufficient QS sub-fraction, with a higher average Mw and a large amount of short alkyl and naphthenic substituents, is more likely to completely dissolve QI sub-fraction. Thus, the resultant mesophase exhibits an excellent fusible deformability. Besides, the structural feature of semi-rigid oligomer could somewhat loosen molecular association of layered stacking and contribute to the slippage between stacked mesogens due to its steric effects, thereby decreasing the softening points of mesophase pitch. Above modified effects are easily implementable during a suitable process of two-stage thermotreatment, such as the processes of preparing MP-4-0.01-1.0, MP-4-0.005-1.0 and MP-3-0.01-2.0 in this study. It is worthwhile to mention that the vacuum treatment is required to be conducted prior to large-scale coalescence of mesophase spheres in order to obtain spinnable mesophase pitch.

The effect of accumulation of polycyclic aromatics in FCC decant oil on subsequent pyrolysis behaviors

To control the liquid-phase carbonization of the petroleum residue, the transition of the aromatics in earlier stages of the thermal conversion and its effect on subsequent carbonization behavior were analyzed. It was found that more monocyclic and dicyclic aromatics was converted to polycyclic aromatics in a comparatively shorter time between 450 and 500 °C. The higher polycyclic aromatics content of the oil accelerated the formation of the anisotropic phase, thus the excessive carbonization of the system was prevented and the lamellar orientation of the pyrolysis product was modified (the time required to obtain a fully developed carbonaceous mesophase decreased by 2 h and the stacking height (Lc) increased from 18.58 Å to 21.18 Å when the polycyclic aromatics content increased by 14.92 wt%). The modified oil obtained by thermal pretreatment (HCTO-RF-B) was converted to a carbonaceous mesophase with a large domain texture and good lamellar orientation (d002 = 3.4599 Å, Lc = 21.94 Å), as well as a low softening point (273 °C) in a short carbonization time (8 h), which is attributed to the higher polycyclic aromatics content (which accelerated the formation of an anisotropic phase) and fewer long side chains (which controlled an appropriate free radical concentration) of the thermal pretreated oil. The fully developed carbonaceous mesophase from HCTO-RF-B had a higher stabilization reactivity, which is attributed to the alkyl chains preserved in the system (C–H substitution indice (ICHS) = 0.7513, alkyl indice (IA) = 0.7690).

Quantitative Molecular Composition of Heavy Petroleum Fractions: A Case Study of Fluid Catalytic Cracking Decant Oil

High-resolution mass spectrometry enables molecular characterization of heavy petroleum fractions for petroleomics research. However, results from mass spectrometry are usually not quantitative. Th...