Recently, due to the rapid increase in the demand for artificial graphite, there has been a strong need to improve the productivity of artificial graphite. In this study, we propose a new efficient process by eliminating the carbonation stage from the existing process. The conventional graphite manufacturing process usually involves a series of stages: the pulverization of needle-type coke, the granulation of pitch and coke premix, carbonation, graphitization, and surface treatment to compensate voids formed within particles. The process seems time-consuming and costly. Therefore, in our proposed shortened process, we have eliminated the carbonization stage. Instead of petroleum-derived pitch, coal tar pitch was employed. Coal tar pitch has a lower softening point than binder pitch. Apart from the cost-effectiveness of the process, it has enhanced the properties of artificial graphite by a uniform coating using a lower amount of hard carbon. In addition, the whole manufacturing time and cost was reduced by 12 h and 20% due to the skipped manufacturing step, respectively. It was observed that the artificial graphite produced by the newly proposed shortened process had improved physical properties related to the density and graphitization degree, and also showed an improvement in electrochemical performance. Raman 3D mapping and the electrochemical evaluation of artificial graphite were mainly used to compare the physical properties. This shortened process not only reduces the manufacturing cost, but also contributes to the improved performance of lithium-ion battery anode material.
As the demand for artificial graphite for lithium-ion battery (LIB) anode materials is on the rise, technologies for optimizing the manufacturing processes and reducing the production costs of artificial graphite are crucial. At the same time, globally, regulations on the generation of harmful volatile substances during the artificial graphite production process are also becoming increasingly stringent. In this study, we focused on a continuous kneading process that minimizes the emission of volatile substances during the manufacturing of artificial graphite. To this end, a carbonized material was first prepared from a mixture of needle coke and binder pitch and processed at 3200 °C using two types of co-rotating twin-screw extruder-based continuous kneading equipment to ultimately obtain artificial graphite. The physical properties of the carbonized as well as graphitized materials were analyzed, which revealed the superior performance of the LIB anode material, namely a discharge capacity of greater than or equal to 350 mAh/g, and an initial efficiency of 91% or higher. Thus, a continuous kneading manufacturing process that emits less harmful volatile substances and provides artificial graphite with sufficient battery performance was demonstrated.
Analysis of the heavy fractions in crude oil has been important in petroleum industries. It is well known that heavy fractions such as vacuum gas oils (VGOs) include heteroatoms, of which sulfur and nitrogen are often characterized in many cases. We conducted research regarding the molecular species analysis of VGOs. Further refine processes using VGOs are becoming important when considering carbon recycling. In this work, we attempted to classify compounds within VGOs provided by Kuwait Institute for Scientific Research. Two VGOs were priorly distillated from Kuwait Export crude and Lower Fars crude. Quantitative analysis was performed mainly using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOFMS). MALDI-TOF-MS has been developed for analyzing high-molecular-weight compounds such as polymer and biopolymers. As matrix selection is one of the most important aspects in MALDI-TOFMS, the careful selection of a matrix was firstly evaluated, followed by analysis using a Kendrick plot with nominal mass series (z*). The objective was to evaluate if this work could provide an effective classification of VGOs compounds. The Kendrick plot is a well-known method for processing mass data. The difference in the Kendrick mass defect (KMD) between CnH2n−14S and CnH2n−20O is only 0.0005 mass units, which makes it difficult in general to distinguish these compounds. However, since the z* value showed effective differences during the classification of these compounds, qualitative analysis could be possible. The analysis using nominal mass series showed the potential to be used as an effective method in analyzing heavy fractions.