Fat Coal Research Articles

Free Radical Reactivity Characteristic in the Secondary Oxidation of Oxidized Coal

ABSTRACT To investigate the reactivity of free radicals during the secondary oxidation phase, the coal surface’s ability to adsorb oxygen and its free radical reactivity were researched. The study uncovered the free radical process behind the spontaneous combustion of oxidized coal. The results indicate that increased active adsorption sites form on the surface of oxidized coal, enhancing the absorption of oxygen. The higher the level of oxidation, the greater the capacity for oxygen adsorption. Coal 1, Coal 2, and Coal 3 represent lignite, gas coal and fat coal, in that order, with their level of metamorphism increasing sequentially. Low-rank Coal 1 contains numerous side chains in its molecular structure, with side chain covalent bonds breaking at a lower temperature of 80°C, leading to the rapid generation of free radicals. During primary oxidation, the free radical structure of low-rank Coal 1 transitions to a relatively stable state, requiring a higher temperature (120°C) for secondary oxidation to trigger chain reactions and transfers. The free radical reaction in oxidized coal is more vigorous compared to raw coal, with increased reactivity in secondary oxidation. The intensity of the free radical reaction in Coal 1–120°C, Coal 2–80°C, and Coal 3–80°C is higher during secondary oxidation.

Multifractal Characteristics of Low-Field Nuclear Magnetic Resonance of Different Rank Coals and Its Permeability Predicting Method.

The permeability of methane in coal is a crucial factor in the production of coal-bed methane (CBM), which is dependent on the pore size distribution (PSD) of coal. The transverse relaxation time cutoff value (T2C) is a crucial parameter in nuclear magnetic resonance (NMR) techniques for converting NMR data into an absolute PSD. To investigate an appropriate approach for predicting the T2C and permeability of different rank coals, this study first revealed, through centrifuge experiments with a centrifugal force of 1.38 MPa, the T2C values of five coal samples: anthracite coal (3 ms), lean coal (8 ms), coking coal (12 ms), fat coal (11 ms), and lignite coal (13 ms). These T2C values were then employed to obtain the absolute PSD values of the coal samples. The results demonstrated that the pore structure characteristics of these coal samples are essentially identical, with micropores constituting the majority, varying between 63.47% and 93.74%. Subsequently, the multifractal analysis method was introduced to establish a new T2C value calculation model. A comparison of the model-calculated T2C values with those obtained from centrifugal experiments revealed an average deviation of only 5.26%. Finally, a new permeability model was developed by conducting multiple regressions on permeability and multifractal parameters. In comparison to classical models, such as the Timur-Coates (TC) model and the Schlumberger Dauer Research Center (SDR) model, the developed permeability model offers more accurate predictions. These results are applicable to pore structure characterization and methane permeability prediction in coal reservoirs of varying rank and other unconventional gas reservoirs.

Influence of Tectonically Deformed Coal-Based Activated Carbon and Its Surface Modification on Methane Adsorption.

A series of coal-based activated carbons (CACs) were synthesized from mylonitized fat coal, a type of tectonically deformed coal (TDC) and symbiotic primary structural coal (PSC), followed by oxidative modification. The pore structure, surface oxygen-containing functional groups, and their influence on methane adsorption by CAC as the simplified coal model were investigated by using low-temperature nitrogen adsorption, Fourier transform infrared spectroscopy, Boehm titration, and X-ray photoelectron spectroscopy. The results showed that tectonic deformation fostered smaller pores, particularly ultramicropores in TDC, dominating methane adsorption. Acid-modified TDC-based activated carbons (ACs) showed higher pore parameters and oxygen-containing functional groups than those of PSC-based ACs. Nitric acid introduced abundant carboxyl groups concurrently increasing the pore volume and specific surface area (SSA), while sulfuric acid-ammonium persulfate treatment resulted in increased lactone groups and a partial collapse/blockage of nanopores. Methane adsorption experiments confirmed the importance of micropores and revealed a significant decrease in capacity owing to increased oxygen-containing functional groups as the primary role, with pore wall corrosion playing a secondary role. Thus, the study highlights the surface effects of TDC on methane adsorption and the potential for producing high-performance methane storage materials from China's tectonic coal resources.

A rigid free-standing supercapacitor electrode material made from fat coal-based activated carbon foam

A free-standing electrode material is a competitive candidate for supercapacitor due to its excellent capacity and volumetric energy density. Currently, most of the studies are focused on the preparations and performances of flexible free-standing electrode materials, whereas few on the development of rigid free-standing electrode materials. Herein, a vitrinite concentrate of fat coal is used as a raw material and carbon black as an addition agent to prepare a carbon foam by way of high-pressure pyrolysis. The prepared carbon foam is activated by KOH solution to further achieve an activated carbon foam by which we have fabricated a rigid free-standing electrode material. The assembled symmetric device with the rigid free-standing electrode material demonstrates an extremely high areal specific capacitance of 2304.41 mF cm−2 at 4 mA cm−2, an outstanding cycling stability of 100 % after 40 000 cycles, and an excellent volume energy density of 10.23 mWh cm−3 at 31.78 mW cm−3. These fascinating electrochemical performances of the electrode material are attributed to unique 3D interconnected porous structure of the activated carbon foam. The micron-sized 3D interconnected pores facilitate the transport of electrolyte ions within the electrodes. Meanwhile, micropores on the 3D interconnected pore wall provide abundant active sites for electrolyte ions.

Study on the Wettability and Methane Desorption Characteristics of Coal under High Pressure with Different Surfactants.

In the process of coalbed methane extraction, due to the strong hydrophilicity of coal, the surface interaction force between water and the coal matrix is strong. The hydrophobic effect of the coal seam during drainage and pressure reduction is not significant, and adsorbed methane is difficult to desorb. In order to reduce the surface interaction force promoting methane desorption between water and coal, the surfactants NH766, G526, and D001 with a concentration of 0.1% were selected. A pressure of 12 MPa, which is close to that used for the on-site mining of coalbed methane in Baode, was selected as the experimental condition to simulate hydraulic fracturing of high fat coal, and the influence of different surfactants on methane desorption characteristics was analyzed. Combining contact angle experiments and infrared spectroscopy experiments, we explored the changes in wettability of the coal samples. We compared the changes in wettability and methane desorption characteristics and explored the similarities between these changes. The experimental results showed that after NH766 treatment, the content of oxygen-containing functional groups in coal rock decreased by 30%, and the contact angle of the coal matrix surface increased by 10°. Furthermore, its hydrophobicity was enhanced, and the desorption amount increased by 24%. In contrast, the oxygen-containing functional groups in coal rock after G526 and D001 treatments increased by 5% and 16%, respectively, and the contact angle of the coal matrix surface became smaller. Furthermore, its hydrophilicity was enhanced, and the desorption amount was reduced by 12.5% and 20%, respectively. NH766 reduces wettability and promotes methane desorption, and it can be applied to improve CBM extraction efficiency. G526 and D001 enhance wettability and inhibit methane desorption, which make them suitable for dust prevention and gas control in coal mines.

Effect of guar gum on dynamic wetting the fat coal surface with octyl phenol polyoxyethylene ether solution

To study the effect of guar gum (GG) on the surface of octyl phenol polyoxyethylene ether dynamic wetting fat coal, the effect of GG addition concentration on physical parameters, sedimentation rate, contact angle, maximum dimensionless wetting length (Ldw(max)) and maximum dimensionless wetting area (Adw(max)) in mixed dust suppression solutions was studied by experimental and molecular dynamic simulation methods. The results show that adding GG does not significantly alter the mixed dust suppression solution surface tension, but it increases the solution viscosity. When the GG concentration is greater than 0.1%, the viscosity of the mixed dust suppression solution increasing extent becomes larger. The impact wetting experiment and contact angle experiment show that when GG concentration is 0.01%, the mixed dust suppression solution contact angle is the smallest, the Ldw(max) and Adw(max) are the largest, and the solution wettability is the best. Compared with the Ldw(max), the Adw(max) has a smaller standard deviation and higher repeatability. Molecular dynamics simulation shows that after adding a trace amount of GG to the water/OP surfactant/fat coal system, the relative concentration coincidence area and interaction energy absolute value between coal and water in the system increases, the water molecules diffusion coefficient decreases, and the system wettability is further enhanced, which further illustrates the experimental results accuracy.

Sulfur migration during co-pyrolysis of high sulfur coking coal with fat coal and lean coal

Desulfurization remains a critical yet challenging aspect of producing high-quality metallurgical coke through pyrolysis. Previous studies have suggested that introducing hydrogen-rich gases may improve sulfur removal efficiency. To further explore this approach, we investigated the effects of volatile matter on sulfur migration during co-pyrolysis of high-sulfur coal (SC) with both fat coal (FC) and lean coal (LC). Our findings indicate that most sulfur is transferred into the coke during pyrolysis, with sulfide and pyrite being relatively easy to decompose, while thiophenes and sulfones tend to be thermally stable. Co-pyrolysis with FC significantly decreased sulfur content in the final coke product, while co-pyrolysis with LC resulted in higher sulfur content. The comparative analysis points to the beneficial influence of volatile matter in promoting desulfurization through enhanced sulfur transfer into the gas phase and reduced sulfur fixation with nascent coke. These findings offer practical guidance for coke-making industries to optimize coal blending scheme and to achieve efficient desulfurization during coke-making.

Study on the interaction and coking characteristics of low-sulfur meager coal and medium-high sulfur fat coal during co-carbonization process

To expand the scope of coking coal resources and realize the efficient utilization of different types of coking coals, medium-high sulfur fat coal (FC1, FC2) and low-sulfur meager coal (MC) were selected to explore the influence of co-carbonization process on the final coke properties. Using 13C NMR, Raman and FTIR characterization, it is found that FC1 has a higher content of methylene and aromatic bridge carbon, multiple aromatic structure of 3–5 benzene ring, strong branching degree and hydrocarbon generation ability than FC2, which promote FC1 to produce more liquid phase products in the thermoplastic stage, form higher mobility and better fuse with MC. Comparing the properties of coke with different ratios, it is found that the proportion of MC added in FC1 could reach 60%, the cold-state strength of coke was improved and the deterioration of thermal-state strength was unobvious. When the amount of MC in FC2 is 40%, better coke performance can be obtained. This is mainly due to the fact that the actual volatile released during the pyrolysis of FC1 and FC2 combined with MC is higher than the calculated value, this promoted the pyrolysis of Car-Cal/O and inhibited the pyrolysis of Cal-Cal and Car-Car, resulting in more intermediate molecular weight aromatic nuclei and higher 3–5 membered ring structure content in the thermoplastic process, thus improving the coke quality.

Experimental Study on Methane Diffusion Characteristics of Different Metamorphic Deformed Coals Based on the Counter Diffusion Method

The diffusion coefficient (D) is a key parameter that characterizes the gas transport occurring in coal seams. Typically, D is calculated using the desorption curve of particle coal. However, this method cannot accurately reflect the diffusion characteristics under the stress constraint conditions of in situ coal seams. In this study, different metamorphic deformed coals of medium and high coal rank were considered based on Fick’s law of counter diffusion. The change laws of D under different confining pressures, gas pressures, and temperature conditions were tested and analyzed, and the influencing mechanisms on D are discussed. The results showed that D of different metamorphic deformed coals exponentially decreased with an increase in confining pressures, and exponentially increased with increases in gas pressures and temperature. There is a limit diffusion coefficient. The influence of the confining pressure on D can essentially be determined by changes in the effective stress, and D negatively affects the effective stress, similar to permeability. The effect of gas pressure on D involves two mechanisms: mechanical and adsorption effects, which are jointly restricted by the effective stress and the shrinkage and expansion deformation of coal particles. Temperature mainly affects D by changing the root-mean-square speed and average free path of the gas molecules. Under the same temperature and pressure conditions, D first increased and then decreased with an increase in the degree of deformation. D of the fragmented coal was the largest. Under similar deformation conditions, D of the high-rank anthracite was larger than that of the medium-rank fat coal. Porosity is a key factor affecting the change in D in different metamorphic deformed coals.

A detailed magnetic characterization of combustion products from various metamorphic grade coals

The magnetic properties of combustion products from various metamorphic grade coals including lignite, flame coal, gas coal, fat coal, baking coal and lean coal and anthracite coal, were analyzed. This study was carried out by means of basic magnetic parameters, thermomagnetic and hysteresis measurements. The mass magnetic susceptibility (χ) values ranged from 327 × 10−8 m3/kg to 1722 × 10−8 m3/kg, with an average value of 892 × 10−8 m3/kg, demonstrating a considerable amount of ferrimagnetic minerals in these burned coal samples. The lower χ and SIRM values for the burned lignite were probably due to the lower content of magnetite. A characteristic feature of combustion products was their high values of frequency dependent susceptibility (χfd%), indicating the presence of a large amount of superparamagnetic grains of ferrimagnetic minerals within the combustion products. Thermomagnetic analyses of various combustion products showed the dominant role of magnetite-like phase. Moreover, a significant amount of hematite was also only identified in the combustion product from Flame coal. While the combustion products from Flame coal and Fat coal were characterized by a relatively narrow loop, characteristic of magnetically soft ferrimagnetic minerals, other combustion products including lignite, gas coal, baking coal, lean coal and anthracite coal displayed wasp-waisted loops, indicating the presence of two or more coercivity fractions.

Investigation on the mechanism of solvothermal extraction of coals by macromolecular models

In this study, solvothermal extraction of two coals (Fangezhuang fat coal, FGZ; Sima lean coal, SM) were conducted by N-methylpyrrolidone (NMP); the molecular models of corresponding hypercoals (HPC) were firstly constructed besides that of coals to clarify the extractions mechanism, aiming to provide a technically feasible route to investigate the mechanism of other extraction processes. The structural parameters were obtained by means of proximate analysis, ultimate analysis, carbon-13 nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy and Fourier Transform infrared spectroscopy. The results showed that aromatic ring types of both raw coals were mainly naphthalene and anthracene, nitrogen atoms existed in pyrrole and pyridine whilst sulfur atoms in thiophene substantially, aliphatic carbons presented in the form of methyl and methylene groups while oxygen-containing functional groups mainly consisted of phenolic hydroxyl, carbonyl, carboxyl and a few ether bonds. Thus, the macromolecular structure models were constructed, with simulated molecular formulas were C168H136N2O12S, C135H74N2O12S, C166H136N2O6S and C128H82N2O11, respectively. After modifying the macromolecular models by Materials Studio for geometric optimization, annealing dynamics calculation, density simulation and analysis of chemical bonds, these four models reflected the macromolecular structural characteristics precisely. On the other hand, both models of raw coals changed significantly in functional groups, branched chain length and quantity pre and post thermal extraction, indicated that the thermal extraction process was mainly affected by swelling behavior and pyrolysis. This study provided new theoretical support in the development of coal extraction technology and understanding of HPC on the macromolecular level by a model basis.

Experimental investigation on coal desorption characteristics and spontaneous combustion properties evolution under the coupled effect of temperature and pressure

Gas desorption patterns and microscopic pore structure morphology in coal are influenced by the coupled effects of temperature and pressure, and their effects on the spontaneous combustion (SC) characteristics of coal cannot be ignored. In this paper, two types of coal samples, lean coal and fat coal from high gas-prone SC mines, are used as test objects. A self-designed experimental platform for coupling gas adsorption and desorption with coal spontaneous combustion (CSC) and heating and oxidation was used. Firstly, orthogonal tests on the desorption of methane from coal under the coupling effect of different temperatures and pressures were carried out to obtain a gradual decrease of methane desorption from coal with increasing temperature under the same pressure conditions. The results show that the pore volume and specific surface area of coal show a monotonic decreasing pattern with increasing temperature and pressure, while the percentage of micropores and mesopores, which promote the oxygen reaction of coal, show an increasing trend. In addition, a comparative analysis of the characteristic temperature points of the first stage showed that the characteristic temperature points of the desorbed coal were higher than those of the original coal, reflecting the higher SC activity of the desorbed coal; and the crossover temperature points of the lean coal and the fat coal were 79 °C and 88 °C, respectively, after desorption during the heating and oxidation process, which also confirmed the high SC activity of the desorbed coal. Based on the above findings, the methane concentration calculation model of the mining area was applied to redraw the oxidation zone using the mining area of the 41,201 working face of Hongyang No. 2 Mine as an example, and the area was reduced by 39.5%. The research results of the paper can provide guidance for the prevention and control of fire hazards in mines with high gas-prone SC.

A comprehensive insight into the effects of acidification on varied-sized pores in different rank coals

Elucidating the evolution law of coal pore structure under acidification is crucial for guiding the practical application of acidizing technology and improving the production of coalbed methane. To comprehensively investigate the influence of acidification on varied-sized pores in different rank coals, in this study, fat coal, meagre coal and anthracite coal were collected and acidified with a mixed solution composed of hydrochloric acid (9 wt%) and hydrofluoric acid (3 wt%). An approach integrating low-pressure CO2 adsorption (LPGA-CO2), low-temperature N2 adsorption (LTGA-N2) and Mercury intrusion porosimetry (MIP) was adopted to fully characterize the varied-sized pore structure before and after acidification to eliminate the limitations of single method. The results demonstrated that acid treatment improved the pore opening degree and connectivity in coal, but had essentially no effect on the pore shape. After acidification, all the coal samples showed significant increases in the porosity and total pore volume, which was mainly contributed by the numerous newly formed large mesopores and macropores, especially the macropores (with an average contribution rate of 74.59%). Taken as a whole, acid treatment had the largest impact on macropores, followed by mesopores, and the smallest impact on micropores. In addition, the variation trend of total specific surface area (SSA) under acidification was primarily determined by micropores. For the three different rank coals selected in this study, the total SSA of fat coal (PM) was more easily affected by acidification and had the largest percentage increase after acid treatment, followed by anthracite coal (YM), while that of meagre coal (LA) decreased slightly. This difference was driven primarily by the different variation trend of micropore SSA in different rank coals. After acidification, the SSA of ultra-micropores and super-micropores all increased in fat coal (PM) and anthracite coal (YM), whereas for meagre coal (LA), although ultra-micropores SSA increased, super-micropores SSA decreased, which ultimately led to the slight decrease of its micropore SSA. Moreover, the total pore volume increment of coal was closely related to the macropore volume increment under acidification, but not significantly related to the coal maturity,which might indicate that, compared with coal rank, the mineral content in coal might be a more important consideration when measuring the applicability of acidification technology.

Cohesive components in coal and their cohesive mechanism during pyrolysis

The cohesive components in coals and their detailed structure were investigated. The results show that the caking index of Linfen fat coal after extracting by benzene and tetrahydrofuran (THF) decreases from 89 to 43. Through analyzes of FT-IR and synchronous fluorescence spectrometry, anthanthrene is considered as the primary cohesive component to determine the cohesiveness of coal, and it is 42.4 wt% in the extract by THF from fat coal. Meanwhile, 1-naphthol, the secondary cohesive component to influence the cohesiveness of coal, is 22.8 wt% in the extract by benzene from fat coal. The cohesive phenomenon of coal has a positive correlation with the maximum aromaticity index (fa), and the cohesive phenomenon cannot be found during pyrolysis when the maximum fa of samples is smaller than 0.640, which are found from SEM images and XRD spectra of the carbonized samples. Moreover, the addition of anthanthrene makes Shenfu sub-bituminous coal produce cohesive phenomenon that coal particles connect together through the formation of a uniform surface. Based on these findings, a possible cohesive mechanism of coal was proposed.

Research on the Identification Mechanism of Coal Gangue Based on the Differences of Mineral Components.

For coal and gangue, intelligent sorting processes for separation, the use of coal and gangue mineral components with different fundamental differences, and the study of different properties of minerals and coal with different scales and density regarding the gray value change law are presented. The results show that the gray value of single minerals and mixed minerals gradually decreases with the increase of their thickness and density. The greater the density of minerals, the smaller the gray value at the same thickness, and the same rule applies to different coal ranks. Via regression analysis methods, the values of the regression equation parameter a of pure minerals for graphite, quartz, kaolinite, and montmorillonite are 59.25, 65.69, 61.61, and 58.02 in the high-energy region, respectively. In the low-energy region, they are 174.95, 177.31, 186.95, and 161.81. For the regression equation parameter of mixed minerals in the form of two mixed minerals (graphite and quartz, kaolinite, or montmorillonite) and three kinds of mineral mixing (graphite-kaolinite and quartz; graphite-montmorillonite and quartz; graphite-kaolinite and montmorillonite), the gray values are 151.12, 156.00, 153.13,152.43, 152.98, and 151.98 in the high-energy region, respectively; in the low-energy region, they are 193.34, 201.34, 192.93, 191.26, 194.68, and 193.08. The phenomenon for the gray range of two kinds of single minerals locates in the range of mixed minerals that was formed from a single mineral observed after the regression equation of mixed mineral was verified by a single mineral, which agrees with the X-ray recognition pattern. In the end, as the density of coking coal, fat coal, and gas coal increases, the gray value decreases, which was in agreement with single- and mixed-mineral analyses.

STUDY ON THE CALCULATION AND APPLICATION OF THE UNIT ISOSTERIC ADSORPTION ENTHALPY

A series of isothermal adsorption experimental data of lean coal and fat coal has been converted into a temperature-pressure-adsorption equation. The slop of the lnP vs 1/T straight line of Clausius-Clapeyron equation proves that physical adsorption is an exothermic process. The Unit Isosteric Adsorption Enthalpy (UIAE, KJ•mol-1•cm-3•g) is defined as a unit adsorbed amount enthalpy at a fixed adsorbed amount andthe calculation method is presented. The UIAE calculation results prove the surface of the adsorption medium is not uniform, and the interaction between the adsorption molecules occurs. At the same isosteric adsorption condition, lean coal has higher priority to carry out the exothermic process than the fat coal.

Analysis of the Physical and Chemical Properties of Fat Coal at Different Pyrolysis Temperatures in UCG Environment

Analysis of the Physical and Chemical Properties of Fat Coal at Different Pyrolysis Temperatures in UCG Environment

Pore structure development of oxidized coal and its effect on oxygen adsorption capacity

ABSTRACT To explore the surface properties of oxidized coal and reduce its risks of spontaneous combustion, the pore structure development of oxidized coal and its effect on oxygen adsorption capacity were studied by using liquid nitrogen adsorption and oxygen adsorption analysis techniques. The results show that the pore structure development of oxidized coal increases the pore volume and specific surface area. Micropore surface area is the main component of the specific surface area of coal. The mesopores of oxidized coal break into micropores and small pores. Among them, micropores are the most developed to generate more active adsorption sites, and the order of micropore growth is Coal 1 lignite>Coal 3 fat coal>Coal 2 gas coal. A deeper oxidation degree of coal corresponds to a greater number of active adsorption sites generated on the oxidized coal surface, which promotes the adsorption of oxygen on the surface. The order of oxygen adsorption capacity growth is Coal 1 lignite>Coal 3 fat coal>Coal 2 gas coal. The specific surface area is positively correlated with the maximum oxygen adsorption capacity. The order of sensitivity of the maximum oxygen adsorption capacity to the growth of specific surface area is Coal 1 lignite>Coal 2 gas coal>Coal 3 fat coal. The pore structure development could promote the generation of active adsorption sites and enhance the oxygen adsorption capacity of the oxidized coal surface.

Study on the effect of coal microscopic pore structure to its spontaneous combustion tendency

Coal is a porous medium. Due to the large number of pores in coal and the pore size on its surface, usually ranging from millimeter to nanometer, it is difficult to measure and analyze the microscopic pore structure of coal. In order to investigate the effect of the microscopic pore structure of coal on its spontaneous combustion tendency, coal samples from different coal mines of the Kailuan Group were selected as the research objects, and the data of the microscopic pore distribution of three different coal samples were measured by using mercury injection apparatus. The regression analysis of microscopic pore data of coal samples obtained in the mercury injection experiment shows that the correlation coefficients of the regression curves are all greater than 0.94 and the fitting degree is good, indicating that there is a good correlation between the pressure, mercury intake and pore size of the coal samples, indicating that the fractal dimension of pore distribution is very effective. The fractal dimension is generally between 2 and 3, indicating that the microscopic pores of coal samples have good fractal characteristics and meet the fractal theory to describe the distribution characteristics of microscopic pores in porous media. Through the simulation system of natural combustion of coal, the simulation experiment of temperature rise oxidation of different coal samples (gas coal, fat coal, and coke coal) was carried out, and the curve of the concentration of gas products CO and CO2 in the process of temperature rise and oxidation of coal samples was drawn in the experiment. The experimental results show the relationship between the distribution structure of coal pores and its spontaneous combustion tendency, and the coal with a good distribution dimension has a stronger combustion tendency

Comparative study on coal blending and coke-making property of two kinds of thermal dissolution soluble fractions from lignite and coking coal

Thermal dissolutions (TDs) of Xilinguole lignite (XL) and coking coal (CC) with different solvents were performed, and feasibility of applying TD soluble fractions (TDSFs) to coke-making was evaluated. The results show that the TDSFs yield of XL (< 30%) is lower than that of CC (> 40%) in both polar and non-polar solvents at 360 °C. Methanol remarkably enhances TDSF yield of XL from 30% to 45.3% with 10% addition to 1-methylnaphthalene (1-MN) due to methanolysis. All TDSFs prepared show better caking property, lower softening temperatures, and greater caking indexes (GR.I) than the commonly used fat coals for coke-making. Using 5 wt.% TDSFs to substitute equivalent amount of fat coal in coal blends effectively improves the quality of the resultant coke, verifying the feasibility of using TDSFs from low rank coals for coke-making.