Toluene Insolubles Research Articles

Improving the Energy Density of Potassium‐Ion Batteries Through Defect Engineering

AbstractPotassium‐ion batteries (PIBs) have a significant cost advantage in resources, making their commercial application imminent. Presently, the cycling lifespan and energy density of PIBs lag behind those of lithium‐ion batteries, highlighting the crucial need for anode materials suitable for potassium storage. This paper used high‐pressure heat treatment and extraction methods to obtained toluene insoluble (TI) as a carbon matrix, followed by nickel and nitrogen co‐doping to synthesized anode materials (NiNTI). NiNTI is characterized by defect engineering such as thermal condensation polymerization and template doping, which destroys the flattening of the material, provides more active sites, forms more disordered carbon structures, generates a large number of defects and structural vacancies, and improves the electronic conductivity of NiNTI materials. In the NiNTI half‐cell configuration, operating at a current density of 0.1 A g−1, the reversible specific capacity reaches 364 mAh g−1, with an initial coulombic efficiency of 64.9%.

Mechanisms associated with sulfidation gas release, desulphurisation and degradation of rubber powder in crumb rubber modified asphalt

ABSTRACT Odorous sulphidation gases are released during the construction of crumb rubber-modified asphalt (CRMA), causing pollution to the environment. To study the associated mechanism of sulfidation gas (H2S, CH4S, COS and CS2) release and the desulphurisation and degradation of CR in asphalt, the release law of sulphidation gas of CRMA was studied by a gas detector. Gel permeation chromatography (GPC), fluorescence microscope, toluene insoluble (TI) and potentiometric titration tests were used to study the desulphurisation and degradation of CR. The results showed that vulcanised CR in CRMA led to the generation of sulphidation gas with the increase in temperature, time and stirring speed. The average molecular weight of CRMA increased, while the TI and unsaturation (A) decreased after the desulphurisation and degradation of CR. Under the influence of temperature, heating time and stirring speed, the A was reduced by 0.72%∼8.87%, 1.18%∼10.69% and 0.75%∼8.12%, respectively. There was a strong correlation between the concentration of sulphidation gas and the desulphurisation and degradation parameters of CRMA. The reaction of ·H, –CH3, CO with the –SxH generated by the C–S, S–S, C=C fracture during the desulphurisation and degradation of CR was the main reason for the generation of sulphidation gas.

Study on preparation of composite carbon rod for high-power electrode from coke with different structural characteristics

Different from lithium-ion batteries, composite carbon rod for high-power electrode was widely used in high-end manufacturing industry due to its good conductivity and low CTE. In this study, semi cokes with different structural characteristics was used as aggregate and coal tar pitch was adopted as binder and impregnant to prepare composite carbon rod for high-power electrode, and the bonding and impregnation behavior was also investigated. It was found that calcination promoted ordered stacking of planar aromatic lamellae of acicular domain texture and aggravated the structural defects of mosaic texture. Coal tar pitch with low aromaticity and high toluene insoluble (TI) as bonded and impregnated pitch possessed higher adhesion but low weight gain ratio after calcination. While higher TI content of coal tar pitch enhanced the weight gain ratio, but the adhesion of composite carbon rod declined. In addition, the carbonaceous sheets derived from coal tar pitch gradually extended and covered the surface of orderly graphited sheets generated from acicular domain texture and contributed to the lowest CTE of 1.43 * 10−6·℃−1 as well as the lowest specific resistance of 6.03μΩ·m. While the structural defects and voids generated from disordered mosaic texture could not be completely filled, thereby resulting in highest CTE of 2.20 * 10−6·℃−1 and highest specific resistance of 9.55μΩ·m.

Biobased tar pitch produced from biomass pyrolysis oils

Petroleum-based carbon solid materials, such as petcoke and coal tar pitch, have decreased in quality and/or availability due to various factors, such as the declining elemental quality of crude oil and the push towards environmental sustainability. Coal tar pitch acts as a binder in smelting anodes for aluminum production, which contributes significantly to the fossil-based CO2 production globally. In an effort to reduce the carbon footprint of these processes, we synthesized a renewable biopitch based on biomass pyrolysis. In comparison to previous studies on biopitch, we utilized pyrolysis bio-oils with reduced oxygen content (<15%). Guayule and switchgrass biomasses served as the biomass of choice, and their bio-oils underwent continuous distillation. Solid residues underwent extraction to remove toluene insolubles (TI), and the remaining fraction underwent heat treatment to ∼ 380 °C. While both the residues and biopitches contained trace amounts of quinoline insolubles (QI), the pitch TI amounted to 32 – 54 wt%. Coking values exceeded 43 wt% for both pitches, making them feasible for anode utilization. The use of distilled partially deoxygenated oils enables greater flexibility for biorefineries to provide a marketable coproduct alongside hydrocarbon fuels.

Preventing of flooding phenomena on vacuum distillation trays column via controlling coking value factor

The occurrence of flooding phenomena (FP) on the vacuum distillation trays column (VDTC) is investigated on a refinery in the middle region of Iran. Accumulation of coke sediment that is occasionally observed in refinery processing using coal tar (CT) feeding is the main reason of the FP on VDTC. This usually occurs at the down-comer areas and the seal pans of the column. Quinolone insoluble (QI) and toluene insoluble (TI) parameters, two routine methods used to measure coke containing sediments, are employed to determine probable critical areas of FP at the down-comers and the seal pans of CT feed in this study. Analyzing the obtained results of QI and TI tests demonstrated that FP at the column is directly related to the quality of CT feeding. For instance, when the QI of the inlet CT in battery 1 increases from 0.56%W in the first sample to 6.5%W in the 25th sample, the vacuum pressure at the top of the distillation column is reduced from − 230 mbar to − 420 mbar. To prevent sediment accumulation of coke and the occurrence of FP, the CT feeds are centrifuged to reduce coke sedimentation at the down-comer areas and the seal pans of VDTC. Moreover, the seal pan trays are replaced by normal ones and all moveable valves with 25 mm diameter on trays 15 and higher in the column, where coke sediment accumulation is observed the most, are modified by installing wider fixed valve (40 mm diameter) trays.

Behavior of Vanadium and Nickel in Hydroconversion of Vacuum Tower Bottoms over Nanosized Slurry Catalysts

The distribution of vanadium and nickel upon hydroconversion of vacuum tower bottoms in the presence of slurried MoS2, Ni7S6, (NH4)0.25 ⋅ WO3, and Fe1 − xS nanoparticles has been studied. The experiments have been performed in an autoclave reactor and in a flow-through hydroconversion unit. It has been shown that the coke yield in hydrocracking reactions increases in the order MoS2, Ni7S6, (NH4)0.25 ⋅ WO3, Fe1 − xS. The proportion of metals in the toluene-insoluble hydroconversion residue increases in the same order. As the hydroconversion temperature increases, the transfer of vanadium and nickel to condensation products increases. According to electron microscopy data for the toluene insolubles, it can be assumed that vanadium and nickel are bonded to carbon, enter into the coke composition, and do not form compounds with the active phase of the MoS2 catalyst.

New Visual Test Method for the Toluene Insolubles in Oil Products

The toluene insolubles (TI) was recognized as coking precursors produced at the initial stage of thermal reaction. The traditional methods can only obtain the overall yield of TI, however, more detailed information, such as the size distribution, and the shape parameters of TI, cannot be provided. In the present work, a new visual test method for the toluene insolubles in petroleum fractions was developed, based on the digital microscopic image processing technology and statistical method. This method can obtain the overall yields of toluene insolubles, provide the particle size distribution and the shape parameters. The optimized test conditions were determined by investigating the influencing factors. The calibration results of this method showed that the relative error of volume concentration is 5%, and the overall error of particle size distribution is less than 5%. Moreover, the detectable concentration of this method is much lower than that of the traditional methods.

Experimental Investigation of Crude-Oil Emulsion Stability: Effect of Oil and Brine Compositions, Asphaltene, Wax, Toluene Insolubles, Temperature, Shear Stress, and Water Cut

Summary An onshore oil well in Japan, referred to as Well M-1 in this paper, experienced a serious emulsion problem soon after the introduction of artificial lift using a hydraulic jet pump. Even though the problem was resolved after switching to a new demulsifier, it is possible that the operator could experience another emulsion problem as the production condition changes in the future and accordingly, the new demulsifier becomes less effective. Therefore, a laboratory case study was conducted to understand not only the cause of the emulsion problem encountered, but also the relative magnitude of several factors affecting emulsion stability. Knowing the conditions that lead to the emulsion problem helps in understanding how to remove the emulsion and in designing intervention treatments to restore long-term well productivity. At first, the oil and brine samples from Well M-1 were mixed and agitated to form emulsion, and subsequently emulsion stability was evaluated. Subsequently, the mixing conditions were altered to investigate the individual impact on the emulsion stability: (1a) replace Well M-1 oil with another field's oil, (1b) replace Well M-1 brine with another field's brine, (2) change concentrations of asphaltene, (3) change concentrations of wax, (4) change concentrations of toluene insolubles, (5) vary temperature between 20 and 70°C, (6) vary shear stress (rotational speed between 3,500 and 15,000 rev/min), and (7) vary water cut between zero and 100%. The result of the emulsion stability in every test was different. All the above factors showed some impact on emulsion stability, except for brine composition and toluene insolubles, which had little impact on emulsion stability in this study. Operationally speaking, because it was found that the emulsion was stabilized by multiple factors, multiple preventative approaches are required to sustain stable production, free of emulsion.

Microwave heating as a novel route for obtaining carbon precursors from anthracene oil

This work describes a novel route for the preparation of pitches by oxidative polymerization of an industrial anthracene oil (AO) in a microwave semi-pilot equipment consisting in a multi-mode applicator having a 2.45 GHz magnetron with variable microwave power. The experimental five variables of microwave heating of AO air-blowing range between 320 and 380 °C (temperature), 0.2–3.9 °C min−1 (heating rate), 1.5–5 h (soaking time), 16–20.5% (air/AO ratio) and 200–1500 g (initial weight). Their effect on the overall microwave air-blowing process is evaluated by means of a statistical analysis. A detailed characterization of the pitches has been carried out in terms of ultimate analysis, softening point, solubility parameters (toluene insolubles (TI) and quinoline insolubles (QI)) and thermogravimetric analysis. The experiments were also carried out by using conventional heating for comparative purposes. The detailed study of the electric energy consumption of the overall microwave treatment allows estimating a significant electric energy saving of about 20% when compared to conventional heating thus representing an excellent result in the production of carbon precursors.

Enhancement of mesophase formation in paraffinic-rich clarified oil using transition metal catalysts (Cr and Cu)

In the present work, we have made attempts to prepare petroleum pitches from paraffinic-rich clarified oil (CLO) by giving thermal treatment at 370 °C in the presence of Cu and Cr catalysts. The feed CLO is predominantly paraffinic in nature, so it takes fairly large thermal soaking time (21 h) to convert into pitch having mesophase content below countable limits. To increase the mesophase content in the pitch or to make mesophase pitch, 3 wt % transition metal catalysts (Cu and Cr) were added to CLO. Addition of transition metal catalysts not only enhances mesophase formation but also helps to reduce thermal treatment time by promoting polymerization and condensation reactions at a faster rate. The mesophase formation pattern reveals that Cu and Cr catalysts increase the mesophase content from below countable limit to 12 and 9 vol %, respectively. This indicates that Cu and Cr showed better catalytic activity for mesophase formation growth. The effect of transition metal catalysts on physico-chemical properties (softening point, coking value, toluene insolubles and quinoline insolubles) as well as the optical texture and physical properties of mesophase pitches were investigated by optical microscope, FT-IR, SEM, NMR, TG/DTG and XRD.

Enhancement of mesocarbon microbead (MCMB) preparation through supercritical fluid extraction and fractionation

Mesocarbon microbeads (MCMBs) are a valuable carbon material, and the production of this material highly depends on the reaction conditions and feedstock properties. In the present study, supercritical fluid extraction fractionation (SFEF) technology was used to separate coal tar pitch (CTP) into a series of fractions to enhance MCMB preparation. After SFEF separation, most of the toluene-insoluble (TI) components were concentrated into the unextracted residue. First, optimal carbonization conditions were obtained for CTP through systematic experimental evaluations. Then, the SFEF fractions were heat-treated under the optimal conditions to produce MCMBs, and the relationship between chemical composition and product quality was revealed. Compared with CTP products, MCMBs produced from extracted SFEF fractions showed better morphology, and only a bulk mesophase with poor texture was generated from the unextractable residue. Moreover, the TI fraction had a significant negative impact on MCMB production in carbonaceous mesophase development. The results indicate that supercritical fluid extraction can be used to improve the quality of produced MCMBs by removing undesirable components.

Characterization of Toluene- and Quinoline-Insoluble Extracted from Pyrolysis Fuel Oil-Derived Pitch for Manufacture of C/C Composites

We herein report extraction and characterization of toluene-insoluble (TI) and quinoline-insoluble (QI) from pyrolyzed fuel oil (PFO) derived-pitch. The X-ray diffraction patterns demonstrated that QI component exhibited a more crystalline character than TI component. In addition, analysis by Fourier transform infrared spectroscopy (FT-IR) indicated the presence of signals at 3060 cm-1 for both TI components and QI components, which corresponded to the stretching of aromatic C-H bonds. As the intensity of this signal was greater than that of the peak at 2943 cm-1 corresponding to the stretching of aliphatic C-H bonds, it was clear that these components contained higher quantities of aromatic components than the original pitch sample. Furthermore, thermogravimetric analysis (TGA) indicated that the TI and QI components improved thermal stabilities and residues compared to the pitch sample (i.e., TI 75 wt% and QI 65 wt% at 850 oC). Finally, scanning electron microscopy (SEM) images confirmed that TI components were surrounded by β-resin (quinoline solubles in TI components) between the QI regions, which were themselves composed of aggregated grain-like spheres.

Combined filtration and electric desalination for coal tar pretreatment

ABSTRACTMedium-temperature coal tar needs to be purified before hydrogenation because harmful substances are contained. The removal of solid impurities, desalination, dewatering and demetallization of Northern Shaanxi medium-temperature coal tar through filtration and electric desalination were studied in this paper. Results showed that solid impurities (SI), especially toluene-insoluble (TI) and quinoline-insoluble (QI) are effectively removed. The water content of the treated medium-temperature coal tar was finally reduced from 1.32 wt% to 0.19 wt%, and salt content from 63.8 to 2.4 mg/L. Similarly, the impurity atoms such as S, N, O, Fe and Ca were efficiently removed.

Effects of different extracted components from petroleum pitch on mesophase development

Naphthenic-based petroleum pitch was divided into three components, including heptane-soluble (HS), heptane-insoluble/toluene-soluble (HITS) and toluene-insoluble (TI), by sequential extraction with heptane and toluene. Mesophase pitches were prepared by direct condensation of the extracted components and their mixtures. Effects of different components on formation and development of mesophase structures were investigated. Results showed that HITS was the optimal component for preparation of mesophase pitch with large domain structure, low softening point, high carbon residue and ordered microcrystal structure. Interactive effect indexes were cited to monitor the interaction of these components on mesophase development. The component HS with rich alkyl chains accelerated the carbonization via chain breaking at the initial stage of reaction, and HITS with abundant naphthenic structures alleviated the carbonization through hydrogen-transfer reaction during the aggregation process of aromatic molecules, and TI as initial nucleus could trigger the generation of mesophase spheres. However, the mixture of HS and TI possessed a weaker interactive effect on mesophase development compared to the other two mixtures. This was mainly due to the differences in molecular weight distribution and molecular structure between HS and TI. Furthermore, naphthenic structures had a better improving effect than alkyl chains on the generation of high-quality mesophase pitches.

Hydrocracking of Athabasca VR Using NiO-WO3 Zeolite-Based Catalysts

Hydrocracking of Athabasca vacuum residue (AVR) was carried out in an autoclave using particle and fiber forms of NiO-WO3 zeolite-supported catalyst. AVR hydrocracking was performed at 400 °C at low and high H2 pressure of 70 and 365 psi, together with the corresponding control thermal cracking runs. The yield of the different products and the quality of the upgraded liquid was used to assess the catalyst performance. Similarity among energy consumption for the different samples suggested major thermal cracking endothermic reactions. In general, the catalytic runs provided better quality maltene product, whereas better quality product oil was only attained at high pressure. The catalytic runs at low H2 pressure gave the highest yield of combined asphaltenes and toluene insolubles. This yield, on the other hand, was the lowest for the fiber form at high H2 pressure. Simulated distillation results captured the superior performance of the fiber catalyst at high H2 pressure and showed ∼50% conversion of the r...

Catalytic thermal cracking of Athabasca VR in a closed reactor system

Catalytic thermal cracking of the residue is less common, due to high susceptibility of catalysts to deactivation. In this work, cracking of Athabasca vacuum residue in an autoclave at 400 °C was investigated in presence of in situ prepared and commercial alumina nanoparticles as well as drill cuttings. A high liquid yield of ∼90 wt% was obtained. The nanoparticles and drill cuttings (at 30 wt%) contributed to relatively high coke and gas yields. Nevertheless, the catalytic runs had higher quality maltene product. Reducing drill cuttings concentration to 10 wt% gave the highest liquid yield with high quality maltene. Coke inhibition in presence of optimum drill cuttings concentration is attributed to a balance between the rate of coke precursor formation and adsorption onto the cuttings. Subsequently, at a higher temperature, 420 °C, the higher rate of precursor formation led to similar results between the 10 wt% drill cuttings and the control sample. Both toluene insolubles and produced asphaltenes displayed a lower H/C ratio than asphaltenes in the feed, in line with the thermal cracking activity. Thermogravimetry profiles for the produced asphaltenes was attained at higher temperatures than the toluene insolubles, and was initial-mass sensitive. Accordingly, thermogravimetry profiles should not be indefinitely used to identify the different oil fractions.

Characterization of Upgraded Oil Fractions Obtained by Slurry-Phase Hydrocracking at Low-Severity Conditions Using Analytical and Ore Catalysts

A heavy crude oil and its upgraded oils, obtained by batch slurry-phase hydrocracking at low-severity conditions with and without analytical-grade and ore catalysts rich in iron and molybdenum, were fractionated by atmospheric distillation and were deasphalted with the aim of identifying the fraction responsible for the upgrade of the flow properties. Light cuts were separated from the distillation bottoms at 260 °C. This latter fraction was further deasphalted with heptane at 25 kg/cm2 and 60 °C for separation of maltenes and heptane insolubles. The heptane insolubles were subsequently fractionated into asphaltenes and toluene insolubles by Soxhlet extraction. Light cuts, bottoms, and maltenes were characterized by density, viscosity, simulated distillation, and elemental analysis. Light cuts were also characterized by PIONA analysis. Elemental analysis, 1H and 13C nuclear magnetic resonance, X-ray diffraction, and molecular-weight distribution by gel permeation chromatography were carried out for asphal...

Behaviors of coking and stable radicals of a heavy oil during thermal reaction in sealed capillaries

This work studies thermal reaction of a heavy oil at temperatures of 250–500°C in sealed capillaries. The samples are extracted by chlorobenzene and toluene, and the insoluble matters are quantified in mass and in radical concentration. It is found that the chlorobenzene insolubles (CI) forms at temperatures of and higher than 440°C while the toluene insolubles (TI) forms at temperatures higher than 350°C. Both of these insoluble matters increase with time and temperature, and approach to similar asymptotic values. The CI formation can be fitted with a combination of the second-order and autocatalytic kinetics while the TI formation can be fitted with the second-order kinetics. Both CI and TI contain stable radicals measurable by electron spin resonance (ESR), and the radical concentration in CI is higher than that in TI. The kinetics of stable radical concentration in CI and TI are different from that in mass, except that of TI at a low temperature range (350–440°C). The changes in ESR line width of CI and TI are also studied. The above data are also discussed in terms of hard coke (CI insoluble matters) and soft coke (the difference between TI and CI), and in activation energy.

Structural and compositional evolution of coal tar toluene insoluble during slurry-phase hydrocracking

Toluene insoluble (TI) is an important heavy components of coal tar. It significantly affects on residues upgrading and coke formation during slurry-phase hydrocracking. The structural and compositional evolution of TI were investigate in hydrocracking experiments with oil-soluble catalysts. Experiment results showed that the concentrations of TI after hydrocracked initially decreased and then increased as the increase of reaction temperature. And TI consisted organic aromatic compounds and inorganic species. At low temperatures, the TI evolution involved the thermal decomposition along with the elimination of heteroatoms groups. The Fe1−xS was formed by self-sulfurized from inorganic matters and was studied. At relatively high temperatures, the TI evolution included both mesophase and coke formation through the aromatic sheet stacking of rich-oxygen compounds. On the basis of experimental studies, the pathway of the TI evolution was proposed for slurry-phase hydrocracking.

Thermal cracking of Athabasca VR and bitumen and their maltene fraction in a closed reactor system

Thermal cracking of Athabasca vacuum residue (AVR) and Athabasca bitumen (AB) and their maltene fraction was investigated at 400°C in a closed system, i.e. autoclave. The effect of the following variables on the product yield and the properties of the liquid fraction and its maltene extract was evaluated: residence time, pressure of the reactor unit, stirring, temperature and asphaltenes content of the feedstock. The yield of the different fractions, the total energy consumption, the pressure buildup in the batch reactor and the °API gravity and viscosity of the liquid fraction and its maltene extract were used to evaluate the impact of a given parameter. In addition, high-temperature simulated distillation (HTSD) analysis of the liquid product and gas chromatography (GC) analysis for gas product were performed. The effect of reaction time, mixing and pressure on the yield of toluene insolubles (TI) depended on the presence of asphaltenes in the feedstock. TI yield increased at the expense of the asphaltenic fraction when reaction time, mixing and pressure increased. There is an inverse relationship between the initial asphaltenes content in the feedstock and the overall asphaltenes yield base on the parent feedstock. Moreover, increasing asphaltenes content of the feedstock did not introduce significant changes in the total energy input to the reactor.