Desorption Intensity Research Articles

In Situ Exsolved CuZn Alloy Electrocatalysts for CO2 Conversion to Tunable Syngas Production

AbstractAlloying is considered as a promising method for syngas (H2 and CO mixture gas) generation. However, it is challenging to elucidate the relationship between the ratios of syngas and alloy components for CO2 reduction reaction. Herein, through tuning the Cu/Zn ratio on CuZn alloy, the H2/CO ratios in CuZn‐2 (Cu/Zn = 0.77) can be tuned in a noticeable range between 0.8 and 5.8 at −0.88 to −1.28 V versus RHE, and a durable stability of 12 h. The CuZn‐2 displays better performance and enhanced dynamics than other samples. Electrochemical impedance spectroscopies and Tafel results reveal that CuZn‐2 behaves kinetically optimized performance. Density functional theory calculations results reveal that CuZn alloy exhibits middle desorption intensity of *H for HER compared with pure Zn and Cu. CuZn alloy effectively decreases the energy barrier of CO2 molecules activated to *COOH relative to Zn, and also the alloy renders it easier for *CO desorb to generate CO for Cu. In situ Fourier transform infrared spectroscopies also observe a significant intensity of *CO on CuZn‐2. This work demonstrates that alloying Cu and Zn can create active sites, in which Cu acts as an auxiliary active site further facilitating *CO generation.

Surface blistering and deuterium retention in chemical vapor deposition tungsten exposed to deuterium plasma

Chemical vapor deposition tungsten (CVD-W) is a promising material for plasma-facing materials. This work evaluated CVD-W samples with a large grain size (CVD-L) and a small grain size (CVD-S) together with rolled W (ND-W) and recrystallized (Rec-W) samples for their performance under deuterium (D) plasma exposure with a flux of 1021 D m−2 s−1 and fluences up to 2 × 1025 D m−2 at a surface temperature of 500 K. Both CVD-L and CVD-S samples featured a columnar grain structure with a preferred orientation close to 〈001〉 || Z, with a more preferred orientation in CVD-L samples. Both CVD-L and CVD-S samples show good resistance to blistering and only few micron-diameter blisters were observed at fluences. In ND-W and Rec-W samples, the number and size of blisters increased with fluence. The D desorption spectra show two desorption peaks in both CVD-W samples at 520 K and 570–604 K. Whereas in ND-W and Rec-W samples, two peaks were at 520 K and 607–700 K. The total D retention in both CVD-L and CVD-S samples was less than 30 % of that in ND-W and Rec-W samples. The low D retention in CVD-W samples was attributed to the low desorption intensities with the peak at 570–604 K. It is suggested that the microstructure of the columnar grain and the 〈001〉 texture in CVD-W samples helps suppressing plasma-induced blistering, therefore reducing D retention. In terms of the stability of the surface integrity and hydrogen isotopes retention, CVD-W demonstrates a significant potential as a wall material for future fusion reactors.

Pore and gas desorption characteristics of primary coal with different degrees of metamorphism

AbstractPore difference characteristics and adsorption/desorption experiments of primary coal with different degrees were explored to study the characteristics of pore structure and gas desorption. The results show that the pore volume increases with the increase in the degree of metamorphism. In primary coal with different degrees of metamorphism, the distribution of micropores, small pores, and medium‐sized pores (by volume) is WY < PM < CY. The distribution of large pore volume and visible pore volume was WY > PM > CY. According to the pore volume distribution law of different metamorphic primary coals, the average pore diameters of WY, PM, and CY were 68.40, 45.60, and 30.50 nm, respectively. The porosity and specific surface area of primary coal with different degrees of metamorphism show a distribution pattern such that WY > PM > CY. For large pore and visible pore, the pore volumes of WY, PM, and CY coal were 0.0785, 0.0587, and 0.0300 mL/g, respectively, and the proportions were 81.86%, 74.49%, and 55.25%, respectively. The porosity of WY, PM, and CY were 11.57%, 9.03%, and 6.57%, respectively, and the specific surface areas were 6.917, 5.826, and 5.611 cm3/g. According to the desorption characteristics of coal bodies with different metamorphic degrees at different time nodes found that the gas desorption at different time nodes shows similar changes under the same adsorption equilibrium pressure. The higher the degree of coal metamorphism, the greater the amount of gas desorption, and the faster the desorption amplitude. The desorption intensity of WY coal is significantly higher than that of PM and CY coal with the increase of desorption time which also verifies the measurement results of pore structure and adsorption constant.

Study on gas desorption-diffusion behavior from coal particles using triple-pore structure models: Experimental, mathematical models, and numerical solutions

To accurately describe gas emissions from coal particles, a conceptual model comprising macropores, mesopores, and micropores has been proposed. On the basis of the conceptual model, two mathematical models were developed for gas diffusion from coal particles: Model Ⅰ includes the effect of desorption, while Model Ⅱ does not. The models were then validated by comparing them to experimental data obtained from gas desorption diffusion kinetic tests. Meanwhile, the effective diffusion coefficients for pores of varying scales were gained and analyzed. The results indicated that both models were capable of providing a reasonable fit to the experimental data; however, Model Ⅱ was unable to provide a good fit to the experimental data from the initial stage, which Model Ⅰ captured well. This indicates that gas desorption could accelerate gas emission from coal particles in their initial state; the increase of the porosity of micropore or macropore has a significant effect on total gas emission and a moderate effect on the initial gas emission volume, whereas the variation of the porosity of mesosphere could have a remarkable influence. This demonstrated that the intensity of gas desorption in coal with abundant mesopores is greater than that of coal with fewer mesopores in the initial desorption phase. In Model Ⅰ, the effective coefficients for pores of different scales varied significantly with increasing pressure, whereas in Model Ⅱ, this was not the case, with the exception of the effective diffusivity of macropores. The results of the current study have significant implications for the determination of gas contents for gas resources calculations, gas flow in the coal matrix, and the prediction of coal seams outburst.

Investigation of the adsorption properties of the sorbent obtained in the process of modification of clinoptilothite in the purification of natural gas from sulfur compounds

The study of the possibility of using modified clinoptilolite as an adsorbent and the adsorption properties of zeolite in the purification of natural gas supplied to gas processing plants from sulfur compounds contained in it is an urgent task. In the experimental study, the adsorbent fraction was chosen as 0.5÷1.0 mm, density - 0.8 g/cm3, adsorbent layer height - 600 mm. Optimal conditions are selected in such a way that the pressure in the experimental process is 0.2-5.0 MPa, the amount of mercaptans in the purified natural gas is 50÷400 mg/nm3, the temperature is 20÷25°C, the gas flow rate is 0.2÷250°C. 0.25 m/s. Experiments IR spectroscopic studies were carried out on a NikoletIS-10 IR spectrometer in the frequency range 400-5000cm-1. The phase composition was studied using a 2DPHASER Bruker X-ray analyzer (CuKa - radiation, 2nd, 20-80 degrees). Electron microscopic images were taken under a Hitachi TM-3000 microscope. Elemental analysis was performed at Oxford Science. The intensity and accuracy of desorption of sulfur compounds adsorbed on clinoptilolite at 250°C, the same results were obtained on NaX zeolite at 320°C. The catalytic activity of regeneration of clinoptilolite at lower temperatures than that of NaX zeolite, although small, made it possible to minimize the decomposition of mercaptans. The purpose of this work is to study the adsorption properties of the sorbent obtained in the process of modifying clinoptilotite during the purification of natural gas from sulfur compounds.

Analysis of the application of methane-bearing capacity test methods in the conditions of Polish mining

The methane hazard is one of the natural hazards occurring in hard coal mining. The content of natural methane in hard coal seams, the so-called methane-bearing capacity, is one of the key parameters that allow for proper assessment of the methane hazard and the state of the threat of gas and rock outbursts. For safety purposes, there is a constant need to improve the methods for the determination of this parameter. In the conditions of Polish mining, the method used for methane-bearing capacity determination is the direct drill cuttings method. This paper contains a comparative study presenting three different methods of methane-bearing capacity determination. Tests were conducted using two direct methods (the drill cuttings method and the United States Bureau of Mines (USBM) method), and the indirect method based on the desorption intensity index. On the basis of the obtained test results, it was found that the results obtained with the USBM method were slightly higher than those obtained with the direct drill cuttings method. Gas losses, an important element affecting the final value of the assay, were also analysed. This comparative study will evaluate the validity and applicability of the above methods under specific conditions in hard coal mining.

Prediction of Gas Emissions in the Working Face Based on the Desorption Effects of Granular Coal: A Case Study

The aim of the study in this paper is to establish a prediction model of gas emission in the working face. The gas desorption variation characteristics of coal with different particle sizes were assessed using physical tests and based on the coal body of No. 2 coal seam in Wangjialing Coal Mine, Shanxi, China, to reveal the influence law of coal particle size on coal gas desorption. The gas desorption characteristics in the working face, the law of gas emission of coal cutting, coal caving, coal wall, and remnant coal in the goaf of the production process were then analyzed after establishing a gas emission prediction model based on the particle size of the coal. The accuracy of the gas emission prediction model was finally validated through actual measurement of the coal particle size distribution and gas emission in the test working face. The results of the current study show that the coal particle size is negatively correlated with the gas desorption capacity within a certain range. The initial desorption intensity of the coal gas decreased with an increase in the coal particle size. However, the initial gas desorption intensity and attenuation coefficient of gas emission were constant after a certain level of increase in the coal particle size. It was found that the average error between the gas emission prediction model and the actual gas emission data in the mining process was 5.29% based on the desorption characteristics of granular coal. Therefore, the established gas emission prediction model can characterize the law of gas emission in the actual production process more effectively. Furthermore, it provides reliable support for the prediction and control of gas emissions from the goaf under the condition of fully mechanized mining with top coal caving.

Effects of the ZSM-5 zeolites on hydrocarbon emission control of gasoline engine under cold start

The feasibility of ZSM-5 zeolite for controlling hydrocarbon (HC) emissions during cold start period of gasoline engine was studied by temperature programmed desorption (TPD) experiment and molecular simulation (MS). Acetylene, 1-butene, propylene, ethylene, acetaldehyde and benzene molecules were selected as representative HCs based on the HC emission components of gasoline engine cold start experiment. TPD experiment was carried on commercial ZSM-5, and desorption intensity curve of ZSM-5 zeolite for main cold start hydrocarbons was obtained. TPD results indicated that ZSM-5 zeolite can retain most of the hydrocarbons after 472 K, and the overall desorption intensity on ZSM-5 zeolite is acetaldehyde>1-butene > acetylene. Then adsorption and diffusion properties of the six main cold start hydrocarbon components on Na-ZSM-5 zeolite with different Si/Al ratio were studied by grand canonical Monte Carlo (GCMC) method and canonical ensemble Molecular Dynamics (MD) method. The results showed that the adsorption and diffusion of single-component hydrocarbons on ZSM-5 zeolite were affected by the number of exchange cations of zeolite, environment temperature, diameter of HC molecules and covalent bond types of HC molecules, and the adsorption capacity and diffusion coefficient were also affected by the competitive effect between the HC components. In competitive adsorption, molecules with large diameters such as acetaldehyde, 1-butene and benzene occupied the main adsorption sites of zeolite, so the adsorption capacity of these three HC molecules was large, while the adsorption capacity of smaller molecules such as ethylene, acetylene and propylene were small.

Adsorption-desorption kinetics and phosphorus loss standard curve in erosive weathered granite soil: Stirred flow chamber experiments

Weathered granite has a high soil adsorption rate and it is difficult to apply phosphate fertilizers. In order to effectively use phosphorus, it is very important to study the intensity and speed of soil retention and desorption of phosphorus. The purpose of this study is to evaluate the kinetics of adsorption and desorption in soils with different erodibility. We selected three weathered granite soils with hugely different erosions: topsoil layer (TL-Tillage layer), laterite layer (LL-Laterite layer) and sand layer (SL-Sand layer). Phosphorus adsorption and desorption experiments were successively carried out in the stirred flow reaction chamber, and the stirred flow experiment under unsaturated adsorption conditions was carried out for the first time. The maximum absorption capacity (qamax) and desorption capacity (qdmax) of phosphorus in TL soil was both greater than that in LL and SL soil. The adsorption process mainly occurs within the first 250 min of the reaction. The desorption ratio (Dr) in the TL soil is smaller than the LL and SL soil. The order of the fast reaction sites proportion (F) is SL > LL > TL in adsorption process and LL > SL > TL in desorption process. Seven key soil property indicators can fit qamax and qdmax values well. In the determination coefficient (R2) of the standard curve of phosphorus loss, SL soil is the larger than TL and LL. The qamax and Dr values measured in the stirred flow experiment are both larger than those in the batch experiment. Among the three soils, LL has the lowest adsorption capacity for P and the highest accessibility. The slow adsorption sites in TL account for the main part, and the adsorption in LL and SL mainly occurs at fast adsorption sites. Through the establishment of the phosphorus loss standard curve, the maximum phosphorus loss in the entire region can be predicted and calculated. This study can provide theoretical basis and reference for phosphorus management in similar soil types or physical geographical areas with severely eroded soils.

In English

The participation of the electronic subsystem of graphene nanoparticles in heat transfer on the interfaphase surface with epoxy polymer, its participation in the thermodestruction processes of epoxy matrix and the concentration interval of the subsystem's influence on the thermal destruction of the polymer matrix are investigated. For such purpose, epoxy resin composites with oxidized and non-oxidized graphene nanoparticles have been used.The particles were obtained by electrochemical method and those are characterized by the same dispersion and analogical of defect spectra. The particles have the same crystal structure, however in composites with oxidized graphene, the participation of the electronic subsystem in thermophysical processes on the interfacial surface is blocked by the atomic layer of adsorbed oxygen. Сomposites of epoxy resin filled with the same particles of nonoxidized and oxidized nanoparticles in the filler content 0.0, 1.0, 2.0, and 5.0 wt%. The multilayered graphene particles were studied by X-ray diffraction analysis (XRD) and Raman spectroscopy (RS) methods. It was shown that the graphene particles are the 2D dimensional structures with about of 100 layers. Desorption curves of epoxy and its composites have been obtained using a programmable thermal desorption mass-spectroscopic (TDMS) technique for fragments with 15≤ m/z ≤108 and temperature interval 35 - 800 оС. The activation energy of desorption was determined from the Wigner-Polanyi equation as 35 - 150 kJ/mol, temperature and mass dependences of the quantity of desorbed atomic fragments have been calculated. It were established the graphene electron subsystem takes part in polymer structure thermodestruction for epoxy composites with nonoxidized graphene enhancing their heat resistance at graphene content С ≤ 1 wt%. With increasing filler content, the thermodestruction behavior in pristine epoxy and its composites with nonoxidized and oxidized graphene is analogical. The thermodestruction characterizes by the stepwise variations in the desorption intensity of atomic fragments. The electron subsystem of graphene particles does not participate in the heat resistance variations.

Dynamics of a soluble surfactant and evolution of daughterly concentration tongue in a Hele-Shaw cell

The origin and evolution of a concentration tongue, which is generated in the volume of a fluid due to the non-uniform desorption of a soluble surfactant, is investigated theoretically by the method of direct numerical simulation. Initially, a film of the soluble surfactant is located on the surface of the fluid that fills up the thin vertical rectangular slot (Hele – Shaw cell), heated non-uniformly from above. The intensity of desorption into the volume is determined by the compression of the film, caused by the Marangoni force, acting along the up boundary in opposite direction to the tangential component of temperature gradient. The dynamics of concentration tongue depends on the intensity of a creeping convective flow, which is produced in the volume jointly by the Archimedean and thermocapillary forces. The spatial motion of the fluid and the process of an admixture exchange between the surface and the volume in the Hele – Shaw cell are carried out in the plane of wide vertical boundaries of the cavity. This permits to simulate numerically and clearly visualize behaviour of the contaminants in multifarious fluid systems.

On a threshold of desorption during the pumping of a nanofluid through porous medium

The results of direct numerical simulation are intended to describe the saturation process of a nanofluid through artificial porous medium. The calculations were fulfilled using the hypothesis, which presumed the adsorptive nature of nanoparticles adhesion to the solid boundaries of pores. Mathematical statement of the problem was based on the modified MIM-model and Darcy – Boussinesq equations. The dependence of the desorption intensity on the value of filtration velocity was taken into account in the course of theoretical investigation. It was shown that this factor for concentration redistribution of the immobile impurity led to the steepening of the wave front as a function of time. Phenomenological realization of novel physical assumptions made the results of numerical modeling closer to the experimental data.

Assessment of Heating and Cooling of a Spontaneous Fire Source in Coal Deposits—Effect of Coal Grain Size

Fire hazard assessment in coal mines is performed on the basis of concentrations of particular gases emitted from the heating coal deposit, but more precise criteria and indicators are needed to assess fire hazard properly—both during the temperature rise phase and in the coal bed cooling phase. In the paper the impact of coal grinding on hazard assessment of spontaneous fire development in the coal deposit during heating and cooling the fire source was analyzed. The intensity of desorption of ethane, ethylene, propane, propylene, acetylene, carbon monoxide and hydrogen is the resultant of temperature and grinding of coal samples. The results proved that the ratio of concentrations emitted by standard versus coarsely crushed coal for each of the gases, changed both in the growth phase as well as in the temperature drop phase. It was found that as the temperature rose, the effect of coal grinding on the release of ethane, ethylene, propane, propylene and carbon monoxide decreased. The greatest effect of coal grinding was observed in the case of ethane and propane, while the lowest in the case of hydrogen and carbon monoxide.

Quantitative Effects of Desorption Intensity on Structural Stability and Readsorption Performance of Lithium/Aluminum Layered Double Hydroxides in Cyclic Li+ Extraction from Brines with Ultrahigh Mg/Li Ratio

Lithium/aluminum layered double hydroxides (Li/Al-LDHs) have shown great advantages in extracting lithium from low-grade brines without elution dissolution. However, their structures are sensitive and prone to damage in the desorption process. In this study, the quantitative influence of desorption intensity on the structure and readsorption capacity of Li/Al-LDHs was thoroughly investigated with hierarchical desorption conditions obtained by modulating the desorption temperature, eluent consumption, or lithium concentration of the desorption solution. It was found that the experimental readsorption capacity did not continuously improve with the lithium content in Li/Al-LDHs declining with the strengthening desorption. Various measurements were applied to trace the structural transformation of Li/Al-LDHs during the desorption processes, and the generation of gibbsite appeared in Li/Al-LDHs with the structural damages from excessive desorption, resulting in the lowering of the experimental readsorption capacity and poor extraction efficiency of Li+ from brines. The reference intensity ratio quantitative method calculations revealed that the mass fractions of gibbsite in Li/Al-LDHs suffered different excessive desorption, and the results were in agreement with the experimental readsorption capacities for Li+ from the Qarhan Salt Lake brine. In addition, the relationships between the desorption intensity and the Li/Al molar ratio in Li/Al-LDH compositions, as well as the readsorption performance, were systematically investigated to provide a feasible desorption method for the cyclic extraction of Li+. Under the developed conditions, the cyclic extraction of Li+ was nondestructive for Li/Al-LDHs and exhibited stable adsorption capacity during continuous adsorption–desorption cyclic experiments.

Natural desorption of carbon monoxide during the crushing of coal simulating natural rock mass pressure

Carbon monoxide is the principal gaseous indicator in the assessment of indigenous fire hazard. The aim of the research was to determine the natural gas background, not related to the development of endogenous fire in goafs, but resulting from the natural crushing of coal under the pressure of overlaying rocks. A special prototype research devise simulating the processes occurring a coal mine was designed and constructed to achieve the objective of the study. The paper presents a practical method of fire risk assessment in caving longwall goafs taking into consideration the natural emission of carbon monoxide. The authors discuss the results obtained with the application of a prototype research device designed to determine an estimative natural emission of gases from coal. The value of the index of carbon monoxide desorption intensity enables to recognize and forecast the degree of fire hazard. The method consists in measuring the components of atmosphere emitted from a coal sample compressed with a force reflecting the pressure exerted on the rock mass. The method considers in particular the exploitation longwalls with residual coal in goafs. It was observed that the index of carbon monoxide desorption intensity is useful for the assessment of endogenous fire hazard in a coal mine.

Desorption of 2-Nitrophenol from Activated Carbon Under the Action of Biotic and Abiotic Factors

The efficiency and peculiarities of 2-nitropenol (NP) desorption from activated carbons under the action of biotic and abiotic factors have been studied. The biotic NP desorption during one month reached 25–30% of the initial saturation of sorbent. The rational duration of bioregeneration was found to be equal to 14 days. The rate of biotic desorption is shown to be limited by the rate of internal diffusion. The intensity of self-bioregeneration of biological activated carbon is by an order of magnitude less that the NP destruction rate in the solution volume and to a greater degree corresponds to the intensity of abiotic desorption.

Dynamic behaviours of reservoir pressure during coalbed methane production in the southern Qinshui Basin, North China

During the coalbed methane (CBM) reservoir depletion, accurate determination of the dynamic characteristics of reservoir pressure is essential to evaluate the effective desorption intensity, interwell interference, multi-layer production, and productivity. Based on the study on the propagation of pressure perturbation and gas desorption area in the stage above and below the critical desorption pressure (CDP) respectively, an analytical mathematical model is established to characterize the dynamics of reservoir depressurization. Then with a field case study on the reservoir pressure depletion in the southern Qinshui Basin, North China, the variation laws of reservoir pressure during CBM production are analysed and discussed. In the stage above CDP, the average reservoir pressure decreases linearly under the constant water production rate. With the location farther away from the wellbore, pressure gradient progressively decreases and rate of pressure change at a fixed location shows a fast to slow pattern. In the stage below CDP, the gas desorption area expands gradually and similar variations are observed between the average reservoir pressure and bottom-hole pressure, both showing a fast to slow pattern. This shows that the reservoir pressure depletion depends dramatically on the variations of bottom-hole pressure. It verifies the reasonability of this mathematical framework after a comparison of calculation results and changing laws between this study and tank-type model. This study is meant to provide a theoretical guidance for the management and optimization of wellbore dewatering during CBM extraction.

Rotational state modification and fast ortho-para conversion of H2 trapped within the highly anisotropic potential of Pd(210)

The rotational state and ortho-para conversion of ${\mathrm{H}}_{2}$ on a Pd(210) surface is investigated with rotational-state-selective temperature-programmed desorption (RS-TPD) and theoretical calculations. The isotope dependence of TPD shows a higher desorption energy for ${\mathrm{D}}_{2}$ than that for ${\mathrm{H}}_{2}$, which is ascribed to the rotational and zero-point vibrational energies. The RS-TPD data show that the desorption energy of ${\mathrm{H}}_{2}$($J=1$) ($J$: rotational quantum number) is higher than that of ${\mathrm{H}}_{2}$($J=0$). This is due to the orientationally anisotropic potential confining the adsorbed ${\mathrm{H}}_{2}$, which is in agreement with theoretical calculations. Furthermore, the ${\mathrm{H}}_{2}$ desorption intensity ratio in $J=1$ and $J=0$ indicates fast ortho-para conversion in the adsorption state, which we estimate to be of the order of 1 s.

Non-isothermal desorption and nucleate boiling in a water-salt droplet LiBr

Experimental data on desorption and nucleate boiling in a droplet of LiBr water solution were obtained. An increase in salt concentration in a liquid layer leads to a considerable decrease in the rate of desorption. The significant decrease in desorption intensity with a rise of initial mass concentration of salt has been observed. Evaporation rate of distillate droplet is constant for a long time period. At nucleate boiling of a water-salt solution of droplet several characteristic regimes occur: heating; nucleate boiling; desorption without bubble formation; formation of the solid, thin crystalline-hydrate film on the upper droplet surface, and formation of the ordered crystalline-hydrate structures during the longer time periods. For the final stage of desorption there is a big difference in desorption rate for initial salt concentration (C0) 11 % and 51 %. This great difference in the rate of desorption is associated with significantly more thin solution film for C0 = 11 % and higher heat flux.

Natural content of gases: Carbon monoxide, carbon dioxide, hydrogen and unsaturated hydrocarbons of ethylene, propylene and acetylene in selected bituminous coal seams

Chromatographic analysis of gas desorbed from coal reveals the presence of carbon monoxide, carbon dioxide, hydrogen, ethylene, propylene and acetylene, i.e. gaseous components liberated into the mine atmosphere with the increasing temperature of self-heating coal. Elevated levels of carbon monoxide, dioxide and ethylene were registered as well. Investigations showed that these gases are contained in the coal structure and their liberation to the mine air can be triggered by other factors apart from coal self-heating, for example coal fragmentation or disturbing of the virgin coalbeds by mining operations. The amounts of thus desorbed gases can alter their actual concentrations in the mine air, which serve as indicators of the self-heating propensity of coal. No straightforward relationship was established between the concentrations of individual gaseous components in the mixed-gas desorbed from coals sample and the rank and other physico-chemical properties of coals.Sorption and desorption tests by the volumetric method demonstrated that the volume of sorbed carbon monoxide and dioxide, hydrogen, ethylene, propylene and acetylene is closely related to the coal rank and its porous structure. Low-rank coals with well-developed pore systems tend to absorb/adsorb greater amounts of gases than low-rank coals with a less developed pore structure.Tests established the intensity of gas desorption from coals, showing that nearly 80–90% of carbon monoxide, dioxide and hydrogen accumulated in coals would be released. In the case of adsorbed ethylene, propylene and acetylene that proportion is the lowest (50%–70%).Recalling the Ideal Adsorbed Solution (IAS) theory, simulations were performed to predict the mixed-gas adsorption isotherms for binary gas mixtures containing non-saturated hydrocarbons-gas components that are indicators of the self-heating propensity of coal. It appears that acetylene adsorption in the systems C2H2C2H4 and C2H2C3H6 is a favoured process whilst preferential adsorption in the system C3H6C2H4 is that of propylene.