Experimental study on the permeability of crushed coal medium based on the Ergun equation

Pang, Mingkun; Zhang, Tianjun; Meng, Yukai; Ling, Zhiqiang

doi:10.1038/s41598-021-02524-4

Cited by 9 publications

(5 citation statements)

References 28 publications

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“…In cohesive soils, the deformation process mostly includes the friction and bonding strengths [ 25 ]. As a frictional material, the strength of broken coal and rock masses does not include the bonding strength, but due to the unique particle shape, significant occlusion can occur between the particles [ 26 , 27 ]. Therefore, the friction force overcome during deformation of the broken coal and rock masses can be divided into occlusal and sliding friction forces.…”

Section: Discussionmentioning

confidence: 99%

Study on the distribution pattern of particle re-crushing in the coal and rock mass crushing process under pressure

Song

Zhang

et al. 2022

PLoS ONE

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In order to investigate the compaction and re-crushing characteristics of crushed coal gangue with different gradation, the compaction fractal test was carried out for crushed coal gangue with different Talbol power index n. The compaction deformation parameters such as displacement, stress-strain were analyzed according to the test results. And according to the test results, the compaction deformation relationship of the lateral limit crushed coal rock body considering the gradation is obtained. The test results show that: the crushing of coal rock particles exists in almost the whole compaction process of the crushed coal rock body, and the crushing of coal rock particles has a non-negligible influence on the deformation of the whole crushed rock body; the structural stability of large-size coal rock particles is not as good as that of small-size coal rock particles, and the large-size coal rock is more likely to be crushed under the same stress conditions; the distribution coefficient r of the crushed coal rock body decreases with the increase of axial stress; and before the Before the axial stress reaches 8 MPa, the distribution coefficient r of crushed rock samples tends to increase with n in general, and after reaching 8 MPa and later, the distribution coefficient r of crushed rock samples tends to decrease with n in general; the difference value of particle crushing increases with the increase of axial stress, and the weight value of particle crushing decreases with the increase of axial stress, and the changes of both are non-linear; according to the stress recovery in the compaction process of crushed coal rock body The compaction deformation model of the crushed coal rock body is constructed according to the crushing characteristics of coal rock particles in the stage of compaction, which effectively combines its fine action mechanism with macroscopic physical phenomena in a simple form and has certain practical engineering significance.

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Section: Discussionmentioning

confidence: 99%

Study on the distribution pattern of particle re-crushing in the coal and rock mass crushing process under pressure

Song

Zhang

et al. 2022

PLoS ONE

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“…The first member is a linear function of filtration velocity V and refers to laminar flow, and the second member is a quadratic function of filtration velocity V 2 that refers to turbulent flow. The limits of each flow type are determined by the Reynolds number described by Equation ( 2) [36,37]:…”

Section: Laboratory Model Testing Methodologymentioning

confidence: 99%

Meandering Flow Filter for Phosphorus Removal as a Component of Small Wastewater Treatment Plants—A Case Study

Zawadzka

Siwiec

Marzec

et al. 2023

Water

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Chemical phosphorus removal in wastewater treatment plants can be carried out by precipitation with iron or aluminum salts or by filtering wastewater through a bed of active sorptive material. This work aimed to investigate whether using a meander flow filter filled with the sorption material Rockfos® would improve phosphorus removal efficiency in a selected wastewater treatment plant. Tests were performed under laboratory conditions using a model of a meander flow filter and a similar filter under field conditions at full technical scale. This filter was the final element of a hybrid constructed wetland located in the village of Białka in the municipality of Dębowa Kłoda in southeastern Poland. A laboratory model of a phosphorus removal filter with vertical incomplete baffles forcing a meandering water flow was constructed to determine the hydraulic conditions of the flow. After one year of operation, the filter with horizontal wastewater flow operating at its full technical scale (without meanders) was modified by inserting appropriate baffles that were analogous to those in the laboratory model. The analysis of the hydraulic conditions in the laboratory model showed that, under the assumed conditions, wastewater flows through the filter layer in a laminar motion, so such filters can be modeled using the Kozeny–Carman formula. It was shown that, after approximately a year of operation in a filter operating at full technical scale, before modification, dead spaces formed, thus causing the channel and primarily surface flow of wastewater. The phosphorus removal efficiency during this test period averaged 9.4%. After introducing baffles and forcing meander flow in the filter chamber, the efficiency increased to 40.6%. The results indicate that meander flow filters can improve phosphorus removal efficiency in small wastewater treatment plants.

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“…On this basis, it was obtained that the relationship between permeability, non-Darcy coefficient, and porosity of crushed sample can be fitted using an exponential function . Gas permeability experiments with different stress carried out on crushed coal and rock were used to construct a stress-permeability fitting model by varying the stress conditions and the number of cycles of loading and unloading. , Under constant total stress, permeability to sorption gas increases with a decrease of pressure due to crushed coal and rock swelling , and decreases with increasing pressure due to matrix shrinkage. , Pang et al and Zhang et al , studied the permeability evolution of crushed coal with different porosities and found that porosity is the main factor determining the permeability of crushed coal samples.…”

Section: Introductionmentioning

confidence: 99%

“… 36 , 37 Under constant total stress, permeability to sorption gas increases with a decrease of pressure due to crushed coal and rock swelling 38 , 39 and decreases with increasing pressure due to matrix shrinkage. 40 , 41 Pang et al and Zhang et al 42 , 43 studied the permeability evolution of crushed coal with different porosities and found that porosity is the main factor determining the permeability of crushed coal samples.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Compaction Deformation and Gas Permeability Properties for Crushed Limestone

Yang,

Li,

Wang

et al. 2024

ACS Omega

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The mining goaf is enriched in coalbed methane (CBM) resources, and it is imperative to realize its efficient extraction. The gas permeability properties of the crushed coal and rock in the caved zone of mining goaf are the basis for the study of its internal CBM migration and enrichment law. In this study, the compaction deformation and gas permeability properties of crushed limestone with different particle sizes were revealed. The results show that (1) the deformation resistance capacity of the crushed limestone increased with increasing stress. The decreasing trend of porosity of samples with different particle sizes in the early and later compression periods is significantly different. Particle RR of the lower layer is smaller than that of the other layers. (2) The permeability of the sample decreases with decreasing porosity and nitrogen pressure, and it is between 10 −12 and 10 −10 m 2 . Nitrogen migration within the crushed limestone requires the pseudo-threshold pressure gradient, which ranges from 64.86 to 311.42 Pa/m. (3) The average permeability growth amplitude of the sample shows a logarithmic decreasing trend with the decrease of porosity. The average permeability growth amplitude of the 5− 10 mm sample at the same porosity was 15.9−22.3 times that of the 0.315−0.63 mm sample. (4) The permeability of crushed limestone on both sides of the lower layer in the caved zone is much larger than that of other locations. The results are of great practical significance for accurately predicting the CBM enrichment area of mining goaf and then selecting the final position of the extraction drilling hole.

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Experimental study on the permeability of crushed coal medium based on the Ergun equation

Cited by 9 publications

References 28 publications

Study on the distribution pattern of particle re-crushing in the coal and rock mass crushing process under pressure

Study on the distribution pattern of particle re-crushing in the coal and rock mass crushing process under pressure

Meandering Flow Filter for Phosphorus Removal as a Component of Small Wastewater Treatment Plants—A Case Study

Experimental Study on Compaction Deformation and Gas Permeability Properties for Crushed Limestone

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