The spherical mesophases are the main precursors for the high tap density of carbonaceous anode batteries. However, it is challenging to control mesophase size without coalescence and no deformation since it quickly coalesces into a regular large sphere. Here, we propose a feasible extraction method to refine the spherical size of mesophase using benzene. Thermogravimetric and differential scanning calorimetry analysis of untreated pitch revealed that the maximum temperature for mesophase nucleation should not exceed 410 °C to provoke the nucleation of mesophase spheres while maintaining a high pyrolysis yield. The extraction results showed that the extraction weight tends to decrease with an increase in the solvent ratio. There is an exponential relationship between the influence of solvent ratio and the ability for extraction. The solubility of the spherical mesophase in benzene is size-dependent and can dissolve selectively spherical mesophases smaller than 5 μm. Consequently, a monodisperse spherical mesophase was obtained. The reason for forming uniform mesophase spheres can be explained by their thermodynamic state, as described by the “two-step” classical nucleation theory. Benzene effectively improves the size distribution of spherical mesophase by dissolving small sizes while retaining large ones.

It is difficult to optimize the process parameters of directly preparing carbonaceous mesophase (CMs) by solvothermal method using coal tar as raw material. To solve this problem, a Decision Tree model for CMs preparation (DTC) was established based on the relationship between the process parameters and the yields of CMs. Then, the importance of variables in the preparation process for CMs was predicted, the relationship between experimental conditions and yields was revealed, and the preparation process conditions were also optimized by the DTC. The prediction results showed that the importance of the variables was raw material type, solvothermal temperature, solvothermal time, solvent amount, and additive type in order. And the optimized reaction conditions were as follows: coal tar was pretreated by decompress distillation and centrifugation, the solvent amount was 50.0 ml, the solvothermal temperature was 230 °C, and the reaction time was 5 h. These prediction results were consistent with the actual experimental results, and the error between the predicted yields and the actual yields was about − 1.1%. Furthermore, the prediction error of DTC method was within the acceptable range when the data sample sets were reduced to 100 sets. These results proved that the established DTC for chemical process optimization can effectively lessen the experimental workload and has high application value.

Coking coal is an important raw material for coke production. In this study, in an inert atmosphere, two Chinese coking coal samples were, respectively, heated gradually to 1200 °C to release volatile and form char and coke in succession, then cooled naturally to close room temperature to age the coke. The whole heating and cooling process on carbonization were monitored in situ by simultaneous small and wide-angle X-ray scattering (SAXS-WAXS) technique based on a synchrotron radiation platform. The simultaneous structural changes of pore and skeleton in coal during carbonization are revealed for the first time. The two raw coal samples, with similar carbon content and slightly different coalification degree, undergone a carbonization process similar in whole and different in parts. The carbonization presents approximately three stages during heating process and one stage during cooling process. The coal structure changes wavily during heating and monotonously during cooling. The corresponding structural change mechanism is analyzed.

Coal tar pitch is a product with high carbon content and aromatic compounds. Modified coal tar pitch is a high quality raw material for the preparation of intermediate phase pitch, needle coke, carbon microspheres, et al. In this paper, modified coal tar pitch was used as raw material, nitrogen was used as protective gas, and thermal conversion was carried out at constant temperatures (370, 390, 410, 420 °C). Polarized light microscopy, SEM, elemental analysis, FTIR spectroscopy, Raman spectroscopy and XRD diffraction combined with split-peak fitting were used to characterize the microstructures of the thermal transformation products. The results showed that the Iar and CH3/ CH2 contents of the products increased with the gradual increase of the thermal conversion temperature, and the aromatic content increased. And the higher the temperature at the same heating rate, the more the ideal graphite microcrystal content, and the defective graphite microcrystals are converted into ideal graphite microcrystals during the thermal conversion process. When the reaction temperature exceeds 390 °C, the microstructure of the thermal transformation products is anisotropic spheres, and the small spheres fuse with each other and tend to be basin-like and mosaic structure as the temperature increases.

The team has studied the relationship between the ability of the coals to be dissolved in crude anthracene oil and their composition. The coal samples taken from different deposits in Russia and Mongolia were characterized by different stages of metamorphism and tested by the Fourier transform infrared spectroscopy and Carbon-13 nuclear magnetic resonance. The data of a correlation analysis enabled us to find out that an amount of aromatic structures in coal macromolecules provided the main influence on the thermal dissolution of the coals. The middle-rank coals had the highest rates of coal organic matter transfer to liquid products. The data showed that the dissolution process was accompanied by destruction of weak bonds among aliphatic groups. The amount of methylene groups in the aliphatic part of coal macromolecules had a direct impact on conversion of the coal organic matter into soluble products.

In korea, 500MW standard coal fired power plants were designed and operated for the initial base load, so facility stability was prioritized from facility problem to treatment, but now we needed to research for minimizing greehouse gas emissions at the operation of coal fired power plants. research on various facilities and technologies was actively conducted to reduce environment pollutants was drastically reduced, but research and attempts on coping measures in the event of a reduction facility problem were in sufficient. this study considered investigated ways to minimized pollutants by quickly responding to logic development and application of the load runback concept in case of serious problems with environmental pollutant reduction facilities such as NOx reduction selective catalytic reduction facilities, SOx reduction wet flue gas desulpherisation facilities, and TSP(Total Suspended Particles) collection low temperature electric precipitator.

Coal-based graphite has become the main material of emerging industries. The microstructure of coal-based graphite plays an important role in its applications in many fields. In this paper, the effect of carbon disulfide/N-methyl-2-pyrrolidone solvent mixture extraction on the microstructure of bituminous coal-based graphite was systematically studied through preliminary extraction coupled with high-temperature graphitization. The graphitization degree g (75.65%) of the coal residue-based graphite was significantly higher than that of the raw coal-based graphite. The crystallite size La of the coal residue-based graphite was reduced by 47.06% compared with the raw coal-based graphite. The ID/ IG value of the coal residue-based graphite is smaller than that of the raw coal-based graphite. The specific surface area (16.72 m2/ g) and total pore volume (0.0567 m3/ g) of the coal residue-based graphite are increased in varying degrees compared with the raw coal-based graphite. This study found a carbon source that can be used to prepare coal-based graphite with high graphitization degree. The results are expected to provide a theoretical basis for further clean and efficient utilization of the coal residue resources.

Fluorescent carbon nano-materials with quantum confinement and edge effects have recently piqued attention in a variety of applications, including biological imaging, drug delivery, optoelectronics and sensing. These nano-materials can be synthesized from a variety of carbon-based precursors using both top-down and bottom-up methods. Coal and its derivatives typically include a vast crystalline network and condensed aromatic ring cluster, which can be easily exfoliated by chemical, electrochemical, or physical processes to produce nano-materials. As a result, they are regarded as a low-cost, abundant and efficient carbon source for the fabrication of high-yield nano-materials. Nano-materials synthesized from coal-based precursors have outstanding fluorescence, photostability, biocompatibility and low toxicity, among other properties. Their properties in optical sensors, LED devices, bio-imaging, and photo and electro-catalyst applications have already been investigated. In this review, we have highlighted current developments in the synthesis, structural properties and fluorescence properties of nano-materials synthesized from coal-based precursors.

자연발화 현상은 산업현장 또는 우리 생활 속 어디에서나 발생하며 물질이 대기 중에서 점 화원 없이 스스로 발화되는 현상이다. 화학반응 속도가 빨라져 발생하는 열이 증가하게 되어 자연발화의 위험성은 더욱 커진다. 본 연구에서는 식품과 화장품 소재로 이용되는 안전한 원료를 배합하여 다양한 자연발화 현상 중 특히 석탄 자연발화 방지제를 제조하였다. 인도네시아산 저열량, 저급탄에 대한 Lab 과 Field Test를 통하여 석탄 자연발화 억제 효과를 확인하였다. 옥외 현장 테스트 결과, 비교군(90일 후 발화)에 비하여 본 연구에서 제조한 발화방지제는 120일 이상 우수한 자연 발화억제 효과를 나타내었으 며 실내저탄장에서 50일 동안의 CO의 농도변화를 비교하여 CO 농도 제어 효과를 확인하였다. 비교군 인 석탄, 기존의 발화 방지 방법보다 우수한 결과를 확인하였다. 또한, 환경을 고려한 토양 및 수질 시 험, 작업 근로자를 고려한 발화방지제의 MSDS, 수질, 안 자극 등의 공인시험을 통하여 환경과 근로자 작업환경의 안전성 등을 연구하여 2024년부터 적용되는 실내저탄장용 석탄 발화방지제의 가능성을 확인 할 수 있었다.

The bituminous coal was extracted with different industrial solvents like coal tar (CT), heavy cycle oil (HCO) and with their blends to determine the influence of solvent type on the extract yield, composition, thermal behavior, properties such as solubility to toluene and quinoline. The extracts obtained at 380 °C represented pitch-like solid matter with the softening points of 72–127 °C depending on the solvent used. They were characterized using the elemental and group analysis, FTIR spectroscopy, TG-DTG thermogravimetry and liquid chromatography for benzo(a)pyrene concentration. Also, maltene fractions of some extracts were studied by GC–MS. The results showed coal dissolution and the properties of the extracts to differ greatly depending on the solvent used. Coal tar was more favorable solvent for coal dissolution than HCO. Good correlation between the extract aromaticity and the content of the toluene insolubles was observed. The maltene fractions of the extracts obtained with CT and CT blended with HCO consisted mainly of polycyclic aromatics, and that obtained with the HCO contained also large amount of aliphatic compounds. It was found that the amount of the carcinogenic benzo(a) pyrene (BaP) in the toluene soluble fractions of the extracts were different depending on the solvents used for extraction. The remarkable result was that the BaP concentrations in all extracts were much lower than in the solvents used.

육상으로부터 각종 오염물질이 유입되는 하구역은 오염관리에 주의를 기울일 필요가 있다. 본 연구에서는 석탄회 조립물과 하구의 오염 퇴적물을 혼합하여 저서 환경 개선 효과 및 저서 미생물의 군집 구조 변화를 조사하였다. 하구 퇴적물과 석탄회 조립물을 7:3 의 비율로 혼합하여 1개월 동안 반응시킨 후 환경 및 미생물 군집을 분석하였다. 퇴적물의 환경인자를 분석한 결과, 석탄회 조립물이 혼합된 실험구의 pH는 11까지 증가하였다. 실험구의 DIP 농도는 석탄회 조립물과의 반응을 통해 생성된 인산칼슘으로 인해 대조구 대비 30 % 감소하였다. 또한 대조구 대비 실험구에서 증가한 Gammaproteobacteria 강은 DIP 감소에 영향을 줄 수 있음을 확인하였다. DIN 농도는 대조구 대비 실험구에서 2배 이상 증가하였는데, 이는 높은 pH 및 석탄회 조립물에서 용출되는 NH4 +-N의 영향인 것으로 판단된다. 질소 순환과 관련된 미생물은 대조구 및 실험구 모두에서 확인되지 않았다. 따라서, 석탄회 조립물은 오염된 하구 퇴적물의 DIP 농도 감소에 효과적이며, 저서 미생물 군집이 인의 순환에 영향을 주는 것으로 나타났다.

Effective processing and use of coal slime is of great significance to protect the environment and save resources. Different coal slimes (untreated with 43 wt% ash content, crushed and flotation treated with 10 wt% ash content, and pre-carbonized) were activated with KOH to prepare porous activated carbon. The results show the activated carbon prepared from coal slime with 10 wt% ash had high specific surface area (3037 m2/ g) and pore volume (1.66 cm3/ g), which was ascribed to the suitable contents of minerals as template and oxygen-containing functional groups. Electrochemical measurements exhibited the best specific capacitance of 220 F/g at 0.1 A/g and the cycle stability of over 100% capacitance retention after 1000 cycles at 5 A/g in 6 M KOH solution. Due to the high specific surface area, superior electrochemical performance, and facile and low cost, developing highly porous activated carbon for supercapacitors is one alternative way for effective use of coal slime waste.