• Applied Chemistry for Engineering
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• v.33 no.5
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• pp.496-501
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• 2022

In this study, an anode material for lithium secondary batteries was manufactured using petroleum-based residual oil, which is a petroleum refining by-product. Among petroleum-based residual oils, pyrolysis fuel oil (PFO), fluidized catalyst cracking-decant oil (FCC-DO), and vacuum residue (VR) were used as carbon precursors. The physicochemical characteristics of petroleum-based residual oil were confirmed through Matrix-assisted laser desorption/ionization Time-of-Flight (MALDI-TOF) and elemental analysis (EA), and the structural characteristics of anode materials manufactured from residual oil were evaluated using X-ray crystallography (XRD) and Raman spectroscopic techniques. VR was found to contain a wide range of molecular weight distributions and large amounts of impurities compared to PFO and FCC-DO, and PFO and FCC-DO exhibited almost similar physicochemical characteristics. From the XRD analysis results, carbonized PFO and FCC-DO showed similar d₀₀₂ values. However, it was confirmed that FCC-DO had a more developed layered structure than PFO in Lc (Length of a and c axes in the crystal system) and La values. In addition, FCC-DO showed the best cycle characteristics in electrochemical characteristics evaluation. According to the physicochemical and electrochemical results of the petroleum-based residual oil, FCC-DO is a better carbon precursor for a lithium secondary battery than PFO and VR.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.5
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• pp.612-619
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• 2016

Pitch synthesis reaction was studied based on the effect for chemical composition of feedstock. Feedstock was selected as pyrolyzed fuel oil (PFO) and coal-tar (CT), which are by-products in petroleum and steel industry. Pitch was prepared at $420^{\circ}C$ for 180 minutes on atmospheric pressure by thermal treatment. Thermal stability and softening point (SP) of the prepared pitches were investigated and their molecular weight distribution was analyzed by MALDI-TOF. PFO has various aliphatic compounds and coal-tar has high aromaticity with 3 wt% of primary quinoline insolubles. The thermal property of PFO was enhanced with polymerization reaction during the thermal treatment with increased molecular weight range. But CT was inferior to PFO because of side reaction by hetero elements. CTP was appeared molecular weight by 0~200 m/z.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.4
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• pp.25-31
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• 2021

In this research, in order to effectively utilize the petroleum residue pitch, it was used as an adsorbent for removal of cesium ion. In this experiment, acid modification (hydrochloric acid, sulfuric acid) treatment was performed on the adsorbent to improve the ability to remove low-concentration cesium ions dissolved in water. As a result, when the reaction was performed with 9 M sulfuric acid at 25 ℃ and for 240 min, the removal efficiencies of 1.0 and 2.5 mg/L cesium ions were 66 and 51%, respectively. In addition, as the adsorption time increased in the batch experiment, the removal capacity of 1.0 and 2.5 mg/L cesium ions was improved, and when the adsorption reached for 32 hr, the removal efficiencies were 72 and 68%, respectively. Also, in order to increase the ability to remove the remaining cesium ions, an experiment was performed by temperature change (25, 37, 49 ℃), and 1.0 and 2.5 mg/L cesium ions contained in water under the operating conditions of 49 ℃ and 32 hr showed removal efficiencies of 90 and 81%, respectively. Consequently, these experimental results were intended to be used as an adsorption technology that can economically treat low-concentration cesium ions contained in water.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.652-656
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• 2018

In this study, effects of the reaction pressure were studied for petroleum-based pitch synthesis. A two-stage reaction process was performed based on different reaction pressure conditions. Each stage experiments for the two-stage reaction were consecutively carried out. The first stage was consisted of three different pressure conditions; high (10 bar), normal and low (0.1 bar). And the second stage was carried out at the normal and low (0.1 bar) pressure. The pitch synthesis was realized at $400^{\circ}C$ for 2 h. Thermal properties and molecular weight distributions of each samples were investigated by analyzing the softening point and MALDI-TOF data. Volatilized components during the pith synthesis were measured by GC-SIMDIS. In case of the first-step reaction with the high pressure condition, the low molecular weight component participated to the pitch formation more effectively and the pitch with the low softening point was obtained. However, for the case of the first-step with the low pressure, the low molecular weight component was vent outside and the partial coke formation occurred. Eventually, pitch properties such as the softening point and yield were controlled effectively by changing the pressure in the pitch synthesis reaction.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.331-336
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• 2019

In this study, required properties and optimized procedure conditions for the pitch based soft carbon anode of lithium ion battery was investigated for improving the initial efficiency and rate performance. Each petroleum residue was thermally treated at 360, 370, and $410^{\circ}C$ for 3 hours to synthesis a pitch and the corresponding pitch shows the softening point of 86, 98, and $152^{\circ}C$, respectively. The elemental analysis and thermal characteristics of the pitch were investigated by EA analysis and TGA. It was noted that the low H/C and improved thermal stability were obtained with the high softening point. The obtained pitch was carbonized at $1,200^{\circ}C$ for 1 hour to produce a soft carbon based anode. As a result of investigating the crystal structure by XRD analysis, it was found that the crystallinity of soft carbon increased with increasing the softening point. It was considered that relatively higher boiling components and decreases in the evaporation component resulted the components participation for cyclization during the heat treatment process. The soft carbon based anode with an improved crystallinity shows the enhanced initial efficiency and rate performance. The mechanism of both improvements was also discusssed based on the developed crystal structure of soft carbon based anode materials.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.746-752
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• 2016

In this study, soft carbon was prepared by carbonization of carbon precursor (pitch) obtained from PFO (pyrolysis fuel oil) heat treatment. Three carbon precursors prepared by the thermal reaction were 3903 (at $390^{\circ}C$ for 3 h), 4001 (at $400^{\circ}C$ for 1 h) and 4002 (at $400^{\circ}C$ for 2 h). After the prepared soft carbon was ground to a particle size of $25{\sim}35^{\circ}C$, the soft carbon was synthesised by the chemical treatment with boric acid ($H_3BO_3$). The prepared soft carbon were analysed by XRD, FE-SEM and XPS. Also, the electrochemical performances of soft carbon were investigated by constant current charge/discharge test, cyclic voltammetry and impedance tests in the electrolyte of $LiPF_6$ dissolved inorganic solvents (EC:DMC=1:1 vol%+VC 3 wt%). The coin cell using soft carbon of $25{\sim}35^{\circ}C$ with 3903 soft carbon ($H_3BO_3$/Pitch=3:100 in weight) has better initial capacity and efficiency (330 mAh/g, 82%) than those of other coin cells. Also, it was found that the retention rate capability of 2C/0.1C was 90% after 30 cycles.