Examination of sorption and desorption of hydrogen on several samples of polish hard coals

Cygankiewicz, J.; Dudzińska, Agnieszka; Żyła, M.

doi:10.1007/s10450-012-9393-3

Cited by 21 publications

(17 citation statements)

References 22 publications

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“…The percentage of hydrogen molecules in sorbed gas increases along the increase of carbon percentage and the decrease of oxygen amount. It was observed that the highest amount of sorbed hydrogen was gained for coal containing from 70 to 80% of carbon [14]. This behavior reflects the fact that the hydrophobic character of coal surface constitutes a factor which favors the sorbtion of hydrogen molecules.…”

Section: Resultsmentioning

confidence: 73%

“…This behavior reflects the fact that the hydrophobic character of coal surface constitutes a factor which favors the sorbtion of hydrogen molecules. Furthermore, it has been found that sorption of carbon monoxide is closely related to the number of accessible active sites on coal surface [15]. The number of polar active sites centers in coal is proportional to oxygen content and inversely proportional to its carbon content.…”

Section: Resultsmentioning

confidence: 99%

“…The sorption mechanism of non-polar molecules of propane and ethane is associated with a dispersion interaction [13,16,17]. The varied reactivity of propane and ethane can be related to the energy value of the C-H bond.…”

Section: Resultsmentioning

confidence: 99%

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Sorption characteristic of coal as regards of gas mixtures emitted in the process of the self-heating of coal

Wojtacha‐Rychter

Smoliński

2017

E3S Web Conf.

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Abstract. One of the most challenging tasks in the coal mining sector is the detection of endogenous fire risks. Under field conditions, the distance between the points where samples for the analyses are collected and the actual place where coal self-heating takes place may be quite remote. Coal is a natural sorbent with a diverse character of pore structures which are surrounded by fractures and cleavage planes constituting ideal spaces for the flow and adsorption of gases. The gases (methane, ethane, ethylene, propane, propylene, acetylene, carbon dioxide, carbon monoxide, hydrogen) released from the source of fire migrate through the seam and may be subject to adsorption, or they may cause the desorption of gases accumulated in coal. Therefore, the values of reference sample concentrations may be overstated or understated, respectively. The objective of this experimental study was to investigate the adsorption phenomena accompanying the flow of a multi-component gas mixture through a coal bed which may occur in situ. The research was conducted by means of a method based on a series of calorimetric/chromatographic measurements taken to determine the amount of gases released during coal heating at various temperatures under laboratory conditions. Based on the results obtained in the course of the experiments, it was concluded that the amount of gas adsorbed in the seam depends on the type of coal and the gas. Within the multi-component gas mixture, hydrocarbons demonstrated the largest sorption capacity, especially as concerns propylene.

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Section: Resultsmentioning

confidence: 73%

Section: Resultsmentioning

confidence: 99%

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Sorption characteristic of coal as regards of gas mixtures emitted in the process of the self-heating of coal

Wojtacha‐Rychter

Smoliński

2017

E3S Web Conf.

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“…The setup of the inverse gas chromatograph is presented in Fig. 2. (3) Desorption measurements relied on determining the total amount of product/synthesis gases sorbed in the coal and strata samples located in different parts of in-situ reactor [27,28].…”

Section: The Measurement Methodologymentioning

confidence: 99%

Underground coal gasification (UCG): An analysis of gas diffusion and sorption phenomena

Ludwik-Pardała

Stańczyk

2015

Fuel

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“…The concentration of these gases in mine air increases with the coal temperature . On the basis of the contents of these gases in mine air, gas indices are calculated, which have some limitations in terms of fire hazard assessment since these gaseous products released from the self‐heating source may be sorbed on coal . The molecules are sorbed only in certain places called polar active centers on the surface of coal particles.…”

Section: Introductionmentioning

confidence: 99%

The effect of coal grain size on the sorption of hydrocarbons from gas mixtures

2019

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Summary The flow of gas mixtures through coal, accompanied by sorption, is one of the natural processes occurring in the spontaneous heating of coal in underground mines. So far, studies on the sorption of mine gases have been mostly performed with regard to single components. In turn, sorption measurements with the use of gaseous mixtures were performed only on coals with grain size at the narrow range of 0.5 to 0.7 mm. In this paper, a dynamic sorption of a mixture of propylene, ethylene, propane, and ethane in a fixed‐bed column was investigated. Coal samples of various grain classes, ie, 0.25 to 0.50, 0.7 to 1.00, and 1.00 to 2.00 mm, were used as an adsorbent. The sorption tests were conducted at a constant gas flow rate of 2.17·10−7 m3/s and the pressure of approximately 1 atm. Next, the results of the sorption tests were compared with parameters characterizing the porous structure of the materials used. The total amount of sorbed gases decreases as the grain size becomes larger. The samples characterized by a lower carbon content (<70% w/w), a slightly higher oxygen content, and a larger surface area dominated by micropores at the range of 0.6 to 2.0 nm and mesopores with diameter of 2.0 to 10.0 nm had a higher sorption capacity than samples with the structure determined mainly by mesopores. It has been noticed that a high sorption ability of ethane results from its highest concentration in the mixture at the inlet of the sorption column. In most cases, propylene was sorbed in larger amount than ethylene, independently of grain size of coal and pore size distribution.

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Examination of sorption and desorption of hydrogen on several samples of polish hard coals

Cited by 21 publications

References 22 publications

Sorption characteristic of coal as regards of gas mixtures emitted in the process of the self-heating of coal

Sorption characteristic of coal as regards of gas mixtures emitted in the process of the self-heating of coal

Underground coal gasification (UCG): An analysis of gas diffusion and sorption phenomena

The effect of coal grain size on the sorption of hydrocarbons from gas mixtures

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