Coal Gasification Research Articles

Study on the preparation of amphiphilic coal rock-cement interface enhancer and the interface strengthening mechanism

Coal rock has well-developed bedding and joint, strong brittleness, oil-wet surface, poor affinity with cement, and poor mechanical properties. Therefore, it cannot provide high-quality wellbore sealing, which further restricts the development of coal seam gas through subsequent hydraulic fracturing. In order to further improve the bonding quality of the coal rock-cement interface, the weakening mechanism of coal rock-cement bonding was studied in this paper firstly based on the properties of coal rock itself and the microscopic and macroscopic performance analysis tests. Then the interface enhancement approaches were proposed and a dual-affinity coal rock-cement interface agent GSK-II was prepared at last by surface modification of wollastonite partially, in which the modifier are KH570 and zinc stearate. The optimum preparation conditions were as follows: slurry concentration was 10 %, concentration of modifier KH570 and zinc stearate were 1 % separately, modification time was 50 min, and modification temperature was 60℃. The results showed that the coal rock-cement interface bonding strength was increased by 4.49 times after the amphiphilic interface affinity agent GSK-II was added into the drilling fluid, showing a significant interface enhancement effect. In addition, the results also indicated that the generation of solid particles accumulation zone in coal rock fractures and the hydrophobicity of coal rock surfaces were the main reasons for the deterioration of coal rock-cement interface bonding quality. The main ways to enhance the interface bonding effect are to improve the solidification and compactness of the solid particles accumulation zone, as well as to improve the hydrophilicity of coal rock surfaces. The results of the study provided theoretical guidance for improving the interfacial bonding quality of the wellbore in coalbed methane wells with developed fractures, and laid a solid foundation for the safe and effective implementation of subsequent volume fracturing and other mining technologies for coalbed methane wells, and also provided new ideas for the research and development of interface enhancers in this field in the future.

USE OF PULVERIZED COAL FUEL FOR PREHEATING SCRAP

Preheating of scrap in the converter is an actual area of ​​research in modern metallurgy. The growing requirements for energy efficiency and the reduction of raw material costs encourage the development of new technological solutions to increase the share of scrap metal in the charge of converter production. Traditional methods are often limited to the use of no more than 25% of scrap, which is associated with difficulties in its uniform heating and the possible formation of a liquid phase as a result of local overheating. The work evaluates the effectiveness of traditional and experimental technological solutions, such as two-tier and fuel-oxygen nozzles. The stages of ignition and burning of lump coal and pulverized coal fuel and their influence on the uniformity of scrap heating were studied. Experimental studies have shown that with a specific oxygen consumption of 1-1.35 m³/kg of pulverized coal fuel, uniform heating of scrap metal is ensured without the risk of melting the upper layers. During the use of a fuel-oxygen lance, the following features of heating scrap metal using pulverized coal fuel, which was blown in an oxygen ring shell, were discovered: - during the combustion of coal dust in an oxygen environment, due to the significant total surface of coal particles, the bulk of volatile СmНn does not have time to separate before the beginning particle ignition, and carbon burns at the same rate as volatiles. This contributes to the formation of high-temperature torches with great luminosity, which effectively affect the surface of the scrap; - the coefficient of use of blown oxygen and pulverized coal fuel is significantly higher than when using lump gas coal during heating of any duration. This is due to the greater luminosity of the formed torches, which contributes to the intensive absorption of thermal energy by the surface of the scrap; - the time required to heat the surface of the scrap metal to the specified temperature is reduced, which allows you to avoid the formation of a liquid component that can lead to undesirable consequences, such as uneven heating or damage to the converter lining. Based on the results of experimental studies, the relationship between the specific oxygen consumption and the flame temperature was established. The ability to control the temperature regime during the heating of scrap metal indicates the prospects of using a fuel-oxygen nozzle made of PVP to optimize the converter production process. For the full implementation of the technology, additional research and industrial testing are needed to optimize processes and increase production efficiency.

Thermal coupling study during the co-processing of coal and biomass in the lab-scale adiabatic reactor

A lab-scale adiabatic reactor has been self-made to characterize the coupled properties of heat and reactions during the co-thermal-processing of coal and biomass with steam or steam/O2 gasification agents. Results showed that the synergistic effects caused by heat transfer between corncob and coal at different mixing ratios were heavily determined by coal rank and gasification agent. During steam co-processing, the heat transfer from corncob char to adjacent bituminous coal char promoted the water-gas reaction on coal char and contributed to synergistic effects; the heat transfer from anthracite char to adjacent corncob char reduced the kinetic rate of the water-gas reaction on coal char and contributed to inhibitory effects, and the inhibitory effect caused by heat transfer was greater than the promotion effects of biomass mass transfer. The introduction of O2 diminished the impact of inter-particle heat transfer and altered the intensity of synergy, decreasing the values of synergy factor of bituminous coal/corncob blends by 17% and increasing the value of synergy factor of anthracite/corncob blends by 142.5%. This study provides sufficient support for the process conditions selection for the production of syngas with specific H2/CO molar ratios and the desired level of gasification performance.

Enhanced flotation separation of coal gasification fine slag by composite collectors containing polar fatty acids

Enhanced flotation separation of coal gasification fine slag by composite collectors containing polar fatty acids

Machine learning-based techno-econo-environmental analysis of CO2-to-olefins process for screening the optimal catalyst and hydrogen color

CO2 to light olefins (CTLO) is an attractive strategy for CO2 fixation to obtain high-value-added chemical products. Selecting the optimal catalyst and hydrogen source for the process has become increasingly challenging due to the wide range of developed catalysts and diverse hydrogen sources available. Herein, this study proposes a machine learning-based techno-econo-environmental analysis framework for screening catalysts and hydrogen colors for the CTLO process. The preferred machine learning model is employed to screen the most promising catalyst for the CTLO process, which is then applied to accomplish the conceptual design of the entire process to obtain essential material and energy balance results by process modeling and simulation. Finally, the techno-econo-environmental performance of the CTLO processes using various colored hydrogen are compared to provide more informed choices. The results indicate the extreme gradient boosting model exhibits superior predictive accuracy, making it suitable for integrating with the genetic algorithm to screen the optimal catalyst for the CTLO process. After multi-objective optimization, an optimal Fe-based catalyst is screened and used for the modeling and simulation of the CTLO process due to its highest light olefins yield (36.43%). The carbon, hydrogen, and exergy utilization efficiencies of the CTLO process considering solely the target light olefins are 59.58%, 21.71%, and 40.41%, respectively. After evaluating the impact of different H2 colors on the total operating cost, unit production cost, and minimum selling price of the CTLO process, it was found the CTLO process using gray H2 generated by coke oven gas and coal gasification technologies exhibits the most favorable cost-effectiveness and optimal market price compared to alternative production scenarios. However, using green H2 proves highly advantageous for the CTLO process in attaining comprehensive negative carbon emissions throughout its lifecycle. Moreover, it anticipates the influence of technological advancements and market fluctuations on the market competitiveness of CTLO processes with diverse hydrogen colors.

Experimental and kinetic studies on steam gasification of oxidized carbon-rich fraction from coal gasification fine slag

Gasification is an important method to realize the resource utilization of coal gasification fine slag (CGFS). In this work, the carbon-rich fraction (CF) of CGFS was modified by oxidation, and the gasification reactivities, structures, and kinetics of samples were studied. The results demonstrate that compared to CF, the gasification characteristic temperatures of oxidized CF are lower, the weight loss rates are faster, and the gasification reactivities are significantly enhanced. These improvements are attributed to the structural evolutions of oxidized CF. Compared with CF, the specific surface area and pore volume of oxidized CF increase by at least 2.5 and 1.5 times, the proportions of oxygen-containing groups rise, and the carbon microstructure of different oxidized CF varies significantly. CF oxidized by steam exhibits the most developed porosity and the most disordered carbon microstructure, corresponding to the highest gasification reactivity of all the samples. The kinetics results showcase that the diffusion reaction model is suitable for describing the gasification process of samples, so porosity emerged as the primary factor determining the gasification reactivity. However, the influence of carbon microstructure and active groups on the gasification reactivity of oxidized CF is enhanced when the porosity meets the diffusion requirements of the gasification reaction.

In situ preparation of carbon/zeolite composite materials derived from coal gasification fine slag for removing malachite green: Performance evaluation and mechanism insight

The stockpiling of coal gasification fine slag (CGFS) and the discharge of organic wastewater pose serious environmental threats. The complex synthesis process and limited pollutant removal capacity of CGFS-based adsorbents impede their efficient utilization in organic wastewater purification. In this work, carbon/zeolite composite materials (CZCM) derived from CGFS were prepared in situ using a one-pot method without further crystallization, achieving an ultra-high adsorption capacity (9705 mg/g) and excellent renewability for malachite green (MG). CZCM was identified as a typical mesoporous material with an abundant pore structure, facilitating the migration of MG within the material. Notably, various metal elements (e.g., iron and calcium) and chemical groups (e.g., carboxyl and hydroxyl) from CGFS were retained through this novel preparation method, providing additional adsorption sites and enhancing MG adsorption. The adsorption kinetics and thermodynamics results indicated that physisorption and multilayer adsorption were the primary adsorption modes of MG by CZCM, with the adsorption rate limited by internal diffusion. Furthermore, the adsorption process was found to be exothermic, spontaneous, and entropy-decreasing. Mechanistic investigations revealed that the exceptional adsorption performance of MG by CZCM was primarily attributed to electrostatic attraction and ion exchange, with hydrogen bonding and π-π interactions also playing significant roles. This study provides new insights into the development of CGFS-based adsorbents for organic wastewater treatment, promoting the efficient conversion and practical application of CGFS.

Upcycling Coal Gasification Slag to Enhance the Self-Healing Performance of Asphalt Mixtures

Upcycling Coal Gasification Slag to Enhance the Self-Healing Performance of Asphalt Mixtures

Role of iron ore in enhancing gasification of iron coke: Structural evolution, influence mechanism and kinetic analysis

Role of iron ore in enhancing gasification of iron coke: Structural evolution, influence mechanism and kinetic analysis

Catalytic gasification of a single coal char particle: An experimental and simulation study

The catalytic coal gasification technology has been widely researched and developed under the background of “Carbon peaking and carbon neutrality goals”. Currently, most of catalytic gasification experiments on coal char particles are analyzed by thermogravimetric analyzer (TGA). However, the gasification agent will be subject to diffusion resistance during the reaction because of the sample stacking, making the inherent reaction kinetics unclear. In this study, we investigated the catalytic gasification behavior of single-particle coal char using high temperature stage microscope (HTSM). With the diffusion resistance ruled out, the reaction conditions when using a HTSM are more similar to those inside a real industrial gasifier. Numerical models of the gasification reaction of single-particle coal char were further developed using the kinetic parameters obtained under HTSM. Three models were investigated, including regular spherical structured, irregular spherical structured and porous spherical structured models, representing different morphologies of coal char particles in the gasifier. The gasification characteristics of coal char particles under different K2CO3 catalyst loadings and gasification temperatures were also studied. Compared with the activation energies data of coal char particles without catalyst, the activation energies of coal char particles loaded with 2.2 %, 4.4 %, 6.6 %, and 10.0 % catalysts were reduced by 110 kJ/mol, 116 kJ/mol, 121 kJ/mol, and 126 kJ/mol, respectively. The reaction surface area affects the temperature distribution. The temperature near the irregular spherical particle is about 20 K higher than the temperature near the regular spherical particle.

Design and Simulation of an Igniter for Surrounding-Type Underground In-Situ Coal Gasification

To optimize the gas passage of underground coal igniters and enhance the performance and efficiency of ignition heaters, meeting the demands of actual underground operations, this paper designs a set of annular ignition heaters. By simulating the internal gas flow within the igniter, the pressure distribution and velocity characteristics inside the igniter are analyzed. Utilizing combustion flow field simulation technology, a comparison is made between the heating and ignition effects of annular igniters and central igniters in coal heating. The performance of the deflecting tube under different eccentric angles is simulated to determine the optimal eccentric angle for achieving the best heating effect. The results indicate that annular igniters for underground in-situ coal gasification have significant advantages over traditional igniters in terms of wellbore heating and flame penetration, with the optimal eccentric angle of the igniter being 10°.

Kinetic analysis and model evaluation for steam co-gasification of coal-biomass blended chars using macro-TGA

A macro-thermobalance (macro-TGA) was applied to investigate the steam co-gasification characteristics of the chars produced from Huainan coal (HN), two types of biomasses, sawdust (SD) and wheat straw (WS), and coal-biomass blends at 900–1200 °C under rapid heating conditions. The gasification reaction kinetics were determined by the homogeneous reaction model (VM), shrinking core model (SCM) and random pore model (RPM), and the optimal model was selected by deviation calculation. The results show that the char gasification reactivity increased with the increase of temperature. The promotion effect of biomass semi-coke on coal char mainly occurred in the stage when the carbon conversion rate was greater than 0.5, which is mainly attributed to the migration of active AAEMs to the surface of coal char to catalyze the gasification reaction in the later stage. However, with the increase in temperature, this promoting effect is weakened due to the increasing influence of mass transfer effects over chemical rate control, and increased volatilization of the inorganic species. The RPM model is suitable for describing the coal char gasification process, while the SCM was the model that best fitted the biomass semi-coke and coal/biomass blends, which elucidates the kinetic mechanisms governing the gasification process.

Insights into reaction mechanisms: Water’s role in enhancing in-situ hydrogen production from methane conversion in sandstone

In-situ conversion of subsurface hydrocarbons via electromagnetic (EM) heating has emerged as a promising technology for producing carbon-zero, affordable hydrogen (H2) production directly from natural gas reservoirs. However, the reaction pathways and role of water as an additional hydrogen donor in EM-assisted methane-to-hydrogen (CH4-to-H2) conversion are poorly understood. Herein, we employ a combination of lab-scale EM-heating experiments and reaction modeling analyses to unravel the reaction pathways and elucidate water’s role in enhancing hydrogen production. The labelled hydrogen isotope of deuterium oxide (D2O) is used to trace the sources of hydrogen. The results show that water significantly boosts hydrogen yield via coke gasification at around 400 °C and steam methane reforming (SMR) reaction at over 600 °C in the presence of sandstone. Water-gas shift reaction exhibits a minor impact on this enhancement. Reaction mechanism analyses reveal that the involvement of water can initiate auto-catalytic loop reactions with methane, which not only generates additional hydrogen but also produces OH radicals that enhance the reactants’ reactivity. This work provides crucial insights into the reaction mechanisms involved in water-carbon-methane interactions and underscores water’s potential as a hydrogen donor for in-situ hydrogen production from natural gas reservoirs. It also addresses the challenges related to carbon deposition and in-situ catalyst regeneration during EM heating, thus derisking this technology and laying a foundation for future pilots.

Reduced-Order Model of Coal Seam Gas Extraction Pressure Distribution Based on Deep Neural Networks and Convolutional Autoencoders

There has been extensive research on the partial differential equations governing the theory of gas flow in coal mines. However, the traditional Proper Orthogonal Decomposition–Radial Basis Function (POD-RBF) reduced-order algorithm requires significant computational resources and is inefficient when calculating high-dimensional data for coal mine gas pressure fields. To achieve the rapid computation of gas extraction pressure fields, this paper proposes a model reduction method based on deep neural networks (DNNs) and convolutional autoencoders (CAEs). The CAE is used to compress and reconstruct full-order numerical solutions for coal mine gas extraction, while the DNN is employed to establish the nonlinear mapping between the physical parameters of gas extraction and the latent space parameters of the reduced-order model. The DNN-CAE model is applied to the reduced-order modeling of gas extraction flow–solid coupling mathematical models in coal mines. A full-order model pressure field numerical dataset for gas extraction was constructed, and optimal hyperparameters for the pressure field reconstruction model and latent space parameter prediction model were determined through hyperparameter testing. The performance of the DNN-CAE model order reduction algorithm was compared to the POD-RBF model order reduction algorithm. The results indicate that the DNN-CAE method has certain advantages over the traditional POD-RBF method in terms of pressure field reconstruction accuracy, overall structure retention, extremum capture, and computational efficiency.

Initial Desorption Characteristics of Gas in Tectonic Coal Under Vibration and Its Impact on Coal and Gas Outbursts

The rapid desorption of gas in coal is an important cause of gas over-limit and outbursts. In order to explain the causes of coal and gas outbursts induced by vibration, this paper studies the gas desorption experiments of tectonic coal with different particle sizes and different adsorption equilibrium pressures under 0~50 Hz vibration. High-pressure mercury intrusion experiments were used to measure the changes in pore volume and specific surface area of tectonic coal before and after vibration, revealing the control of pore structure changes on the initial desorption capacity of gas. Additionally, from the perspective of energy transformation during coal and gas outbursts, the effect of vibration on the process of coal and gas outbursts in tectonic coal was analyzed. The results showed that tectonic coal has strong initial desorption capacity, desorbing 29.58% to 54.51% of the ultimate desorption volume within 10 min. Vibration with frequencies of 0~50 Hz increased both the gas desorption ratios and desorption volume as the frequency increased. The initial desorption rate also increased with the vibration frequency, and vibration can enhance the initial desorption capacity of tectonic coal and delay the attenuation of desorption rate. Vibration affected the changes in the initial gas desorption rate and desorption rate attenuation coefficient by increasing the pore volume and specific surface area, with the changes in macropores and mesopores primarily affecting the initial desorption rate and 0~10 min desorption ratios, while the changes in micropores and minipores mainly influenced the attenuation rate of the desorption rate. Vibration increased the free gas expansion energy of tectonic coal as the frequency increased. During the incubation and triggering processes of coal and gas outbursts, vibration has been observed to accelerate the fragmentation and destabilisation of the coal body, while simultaneously increasing the gas expansion energy to a point where it reaches the threshold energy necessary for coal transportation, thus inducing and triggering the coal and gas protrusion. The study results elucidate, from an energy perspective, the underlying mechanisms that facilitate the occurrence of coal and gas outbursts, providing theoretical guidance for coal and gas outburst prevention and mine safety production.

Comprehensive performance investigation of inexpensive oxygen carrier in chemical looping gasification of coal

Coal chemical looping gasification (CLG) using inexpensive oxygen carrier (OC) is a promising technology to obtain H2-rich syngas, and the OCs of copper/iron ore composite with an autothermal capability and red mud have been screened as the potential candidates in our previous investigation. However, the detailed synergetic effect between copper ore and iron ore, and the effect of reaction conditions on syngas production at different reactor scales are still unclear. In this work, the synergetic effect between copper ore and iron ore in composite OCs with different mixing ratios are detailedly investigated through H2 temperature-programmed reduction (TPR) tests. The results indicate that the copper ore addition can contribute the reduction of iron ore and form a new phase of CuFe2O4 between CuO in the copper ore and Fe2O3 in the iron ore, meanwhile observing the composite OC of Cu20Fe80@C generating a stronger synergetic effect in comparison to adjencent OCs. Moreover, the optimization of reaction conditions are conducted in a batch fluidized bed reactor (BFBR) by regulating the temperature, oxygen to fuel (O/F) ratio, and steam concentration for the Cu20Fe80@C and red mud OCs. It is found that a higher temperature is conducive to improving the coal conversion and syngas yield on the whole, but not the H2-rich syngas production. While a lower O/F ratio favors the preparation of H2-rich syngas, and the optimal steam concentration is determined as 50 vol% for both OCs under comprehensive consideration of gasification time, syngas yield and heating cost. Additionally, the copper/iron ore composite OC with excellent CLG performance and bed stability is further confirmed in a semi-continuous fluidized bed reactor (SFBR), which shows the effects of temperature and O/F ratio on syngas production similar to those in BFBR. In summary, the promising copper/iron ore composite OC exhibits good adjustability and adaptability for CLG process in terms of reaction conditions and reactor scales, respectively.

Simulation Study of Gas Seepage in Goaf Based on Fracture–Seepage Coupling Field

In order to solve the problem of gas overrun in the fully mechanized caving face and the upper corner of high gas and extra-thick coal seam, the fracture and caving process of the roof in the goaf is analyzed and studied by using the relevant theories of fracture mechanics and seepage mechanics. The mathematical model of fracture and caving of the immediate roof and main roof in the goaf is established. Combined with ANSYS Fluent 6.3.26, the seepage process of gas in coal and rock accumulation in the goaf under different ventilation modes is simulated. The distribution law of gas concentration in the goaf is obtained, and the application scope of different ventilation modes is determined. In addition, the influence of the tail roadway application and the wind speed size on the gas concentration in the goaf and the upper corner of the fully mechanized caving face is also explored. The results show that, affected by wind speed and rock porosity, along the strike of the goaf, about 30 m near the working face, the gas concentration is low and growth is slow. In the range of 30~160 m, the gas concentration increases rapidly and reaches a higher value. After 160 m, the gas concentration tends to be stable. Along with the tendency of the working face, the gas concentration in the goaf increases gradually from the inlet side to the return side, and the gas concentration increases noticeably near the return air roadway. Along the vertical direction of the goaf, the gas concentration gradually increases, and the concentration of the fracture zone basically reaches 100%. Different ventilation modes have different application scopes. The U-type ventilation mode is suitable for the scenario of less desorption gas in the coal seam, while U + I and U + L-type ventilation modes are suitable for the scenario of more desorption gas in coal seam or higher mining intensity. The application of the tail roadway can reduce the gas concentration in the upper corner to a certain extent, but it has limited influence on the overall gas concentration distribution in the goaf. In addition, when the wind speed of the working face should be controlled at 2.0~3.5 m/s, it is more conducive to the discharge of gas, the method of reducing the gas concentration in the upper corner by increasing the wind speed of the working face is more suitable for the case where the absolute gas emission of the fully mechanized caving face is low, and the effect is limited when the absolute gas emission is high. The above conclusions provide a reference for solving the problem of gas overrun in the goaf and the upper corner of a fully mechanized caving face.

Mechanism analysis on carbon-ash separation of coal gasification fine slag by high internal phase emulsion collector

ABSTRACT Coal gasification slag is a solid waste produced in modern coal chemical industry, its mixed characteristics of residual carbon and ash materials restrict its resource utilization. This study focused on improving the flotation effect of coal gasification slag and reducing the consumption of flotation reagents, a water in oil type high internal phase emulsion collector was prepared, and the microstructure, rheology, stability, particle size and other characteristics of the emulsion collector were analyzed. By comparing with the flotation effect of conventional kerosene collector, when the amount of organic liquid is basically equal, the ash content of the tailings increased by 4.02%, the yield of concentrate increased by 9.79% and the recovery of combustible matter increased by 11.11%. When the combustible matter recovery is similar, the emulsion collector can save 13.40% of kerosene. The flotation kinetics test shows that the emulsion collector can significantly improve the flotation speed. By analyzing the flocculating ability of emulsion collectors, emulsion collectors can significantly improve the flocculating ability of particles, thereby improving the flotation effect. The research results have certain guiding significance for improving the flotation efficiency of coal gasification slag.

Study of the structure guide mechanism of solid phase synthesis of CAN zeolite from coal gasification slag and its fixation of the Cr6+ structure in wastewater

The generation of a large amount of coal gasification coarse slag (CGCS) restricts the sustainable development of the modern coal chemical industry. This paper uses CGCS as raw material, adopts a solid phase synthesis method, saves water resources, is a new method of synthesizing zeolite with low secondary pollution. Different types of anions were used to induce the synthesis of zeolites. Using XRD, FT-IR, 27Al-NMR, 29Si-NMR, BET, SEM, and experimental research methods, the activation and depolymerization of CGCS in the solid phase reaction and the guiding role of anions in crystal growth were studied. The results revealed that the anionic structure with triple rotational axis symmetry can induce the synthesis of single-phase CAN zeolite. Using this rule, CAN zeolite was synthesized using CGCS as raw material and Cr6+ containing wastewater with triple rotation axis symmetry as the structural guide agent, and Cr6+ in wastewater was structurally fixed. Compared to the adsorption effect of CGCS on Cr6+, the results showed that the synthesized CAN zeolite was found to effectively fix Cr6+ (74.98 mg/g) from wastewater, which was much higher than that of CGCS (24.85 mg/g).

Numerical Simulation of the Coal Measure Gas Accumulation Process in Well Z-7 in Qinshui Basin

The process of coal measure gas accumulation is relatively complex, involving multiple physicochemical processes such as migration, adsorption, desorption, and seepage of multiphase fluids (e.g., methane and water) in coal measure strata. This process is constrained by multiple factors, including geological structure, reservoir physical properties, fluid pressure, and temperature. This study used Well Z-7 in the Qinshui Basin as the research object as well as numerical simulations to reveal the processes of methane generation, migration, accumulation, and dissipation in the geological history. The results indicate that the gas content of the reservoir was basically zero in the early stage (before 25 Ma), and the gas content peaks all appeared after the peak of hydrocarbon generation (after 208 Ma). During the peak gas generation stage, the gas content increased sharply in the early stages. In the later stage, because of the pressurization of the hydrocarbon generation, the caprock broke through and was lost, and the gas content decreased in a zigzag manner. The reservoirs in the middle and upper parts of the coal measure were easily charged, which was consistent with the upward trend of diffusion and dissipation and had a certain relationship with the cumulative breakout and seepage dissipation. The gas contents of coal, shale, and tight sandstone reservoirs were positively correlated with the mature hydrocarbon generation of organic matter in coal seams, with the differences between different reservoirs gradually narrowing over time.