Experimental Study on Coal Seam Gas Desorption Characteristics Caused by Moisture under Stepwise Depressurization
Expansion energy is the main factor of coal and gas outbursts, and the gas desorption around the outburst hole is developed in variable pressure conditions. While studying the impact of moisture on gas desorption characteristics, atmospheric pressure desorption is usually used, but its characteristi...
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MDPI AG
2023-04-01
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| Online Access: | https://www.mdpi.com/1996-1073/16/8/3566 |
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| author | Xinjian Li Xiangjun Chen Lin Wang Haoyang Shi Tongyong Yu |
| author_facet | Xinjian Li Xiangjun Chen Lin Wang Haoyang Shi Tongyong Yu |
| author_sort | Xinjian Li |
| collection | DOAJ |
| description | Expansion energy is the main factor of coal and gas outbursts, and the gas desorption around the outburst hole is developed in variable pressure conditions. While studying the impact of moisture on gas desorption characteristics, atmospheric pressure desorption is usually used, but its characteristics under variable pressure conditions have not been thoroughly investigated. In this study, typical outburst coal samples with different water contents from the Jincheng mining area of China were selected as research objects, and the effects of water on gas displacement, desorption, desorption rate, and gas desorption index (K<sub>1</sub>) of drilling cuttings under step-by-step depressurization were analyzed by means of stepwise depressurization and atmospheric desorption experiments. The research conclusions suggest that (1) the amount of gas replacement, which augments rapidly during the inception, increases with the growth of water content under the experimental conditions, and then the rate decreases; (2) the gas desorption falls gradually at different depressurization stages when the humidity is constant, while the total desorption and the drop amplitude taper with the increasing water content; (3) the additional water enhances the desorption rate significantly only at the initial stage, but scarcely has an impact later on; and (4) the value of the drilling cuttings’ gas desorption index (K<sub>1</sub>) shows a downward trend with the developing humidity in each stage of stepwise depressurization desorption. We take humidity as a variable to simulate the desorption process of coal gas around the hole when coal and gas outbursts occur in the laboratory and study the influence of water on the desorption characteristics under desorption conditions of stepwise depressurization. This provides a reference for the purpose of studying the mechanism of coal and gas outbursts from the perspective of energy. |
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| id | doaj.art-dd909db9d2724e61934291c2cfc19f55 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-11T05:03:33Z |
| publishDate | 2023-04-01 |
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| record_format | Article |
| series | Energies |
| spelling | doaj.art-dd909db9d2724e61934291c2cfc19f552023-11-17T19:06:59ZengMDPI AGEnergies1996-10732023-04-01168356610.3390/en16083566Experimental Study on Coal Seam Gas Desorption Characteristics Caused by Moisture under Stepwise DepressurizationXinjian Li0Xiangjun Chen1Lin Wang2Haoyang Shi3Tongyong Yu4State Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454003, ChinaState Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454003, ChinaState Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454003, ChinaState Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454003, ChinaState Key Laboratory of Gas Detecting, Preventing and Emergency Controlling, Chongqing 400037, ChinaExpansion energy is the main factor of coal and gas outbursts, and the gas desorption around the outburst hole is developed in variable pressure conditions. While studying the impact of moisture on gas desorption characteristics, atmospheric pressure desorption is usually used, but its characteristics under variable pressure conditions have not been thoroughly investigated. In this study, typical outburst coal samples with different water contents from the Jincheng mining area of China were selected as research objects, and the effects of water on gas displacement, desorption, desorption rate, and gas desorption index (K<sub>1</sub>) of drilling cuttings under step-by-step depressurization were analyzed by means of stepwise depressurization and atmospheric desorption experiments. The research conclusions suggest that (1) the amount of gas replacement, which augments rapidly during the inception, increases with the growth of water content under the experimental conditions, and then the rate decreases; (2) the gas desorption falls gradually at different depressurization stages when the humidity is constant, while the total desorption and the drop amplitude taper with the increasing water content; (3) the additional water enhances the desorption rate significantly only at the initial stage, but scarcely has an impact later on; and (4) the value of the drilling cuttings’ gas desorption index (K<sub>1</sub>) shows a downward trend with the developing humidity in each stage of stepwise depressurization desorption. We take humidity as a variable to simulate the desorption process of coal gas around the hole when coal and gas outbursts occur in the laboratory and study the influence of water on the desorption characteristics under desorption conditions of stepwise depressurization. This provides a reference for the purpose of studying the mechanism of coal and gas outbursts from the perspective of energy.https://www.mdpi.com/1996-1073/16/8/3566stepwise depressurizationatmospheric desorptiondesorption lawdesorption indexcoal and gas outburst |
| spellingShingle | Xinjian Li Xiangjun Chen Lin Wang Haoyang Shi Tongyong Yu Experimental Study on Coal Seam Gas Desorption Characteristics Caused by Moisture under Stepwise Depressurization Energies stepwise depressurization atmospheric desorption desorption law desorption index coal and gas outburst |
| title | Experimental Study on Coal Seam Gas Desorption Characteristics Caused by Moisture under Stepwise Depressurization |
| title_full | Experimental Study on Coal Seam Gas Desorption Characteristics Caused by Moisture under Stepwise Depressurization |
| title_fullStr | Experimental Study on Coal Seam Gas Desorption Characteristics Caused by Moisture under Stepwise Depressurization |
| title_full_unstemmed | Experimental Study on Coal Seam Gas Desorption Characteristics Caused by Moisture under Stepwise Depressurization |
| title_short | Experimental Study on Coal Seam Gas Desorption Characteristics Caused by Moisture under Stepwise Depressurization |
| title_sort | experimental study on coal seam gas desorption characteristics caused by moisture under stepwise depressurization |
| topic | stepwise depressurization atmospheric desorption desorption law desorption index coal and gas outburst |
| url | https://www.mdpi.com/1996-1073/16/8/3566 |
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