Knowing methane desorption characteristics is essential to define the contribution of adsorbed gas to gas well production.To evaluate the synthetic effect of a clay stabilizer solution on methane desorption kinetics a...Knowing methane desorption characteristics is essential to define the contribution of adsorbed gas to gas well production.To evaluate the synthetic effect of a clay stabilizer solution on methane desorption kinetics and isotherms pertaining to Longmaxi shale,an experimental setup was designed based on the volumetric method.The objective was to conduct experiments on methane adsorption and desorption kinetics and isotherms before and after clay stabilizer treatments.The experimental data were a good fit for both the intraparticle diffusion model and the Freundlich isotherm model.We analyzed the effect of the clay stabilizer on desorption kinetics and isotherms.Results show that clay stabilizer can obviously improve the diffusion rate constant and reduce the methane adsorption amount.Moreover,we analyzed the desorption efficiency before and after treatment as well as the adsorbed methane content.The results show that a higher desorption efficiency after treatment can be observed when the pressure is higher than 6.84 MPa.Meanwhile,the adsorbed methane content before and after treatment all increase when the pressure decreases,and clay stabilizer can obviously promote the adsorbed methane to free gas when the pressure is lower than 19 MPa.This can also be applied to the optimization formulation of slickwater and the design of gas well production.展开更多
Achieving efficient adsorption and desorption processes by controllably tuning the properties of adsorbents at different technical stages is extremely attractive.However,it is difficult for traditional adsorbents to r...Achieving efficient adsorption and desorption processes by controllably tuning the properties of adsorbents at different technical stages is extremely attractive.However,it is difficult for traditional adsorbents to reach the target because of their fixed active sites.Herein,we report on the fabrication of a smart adsorbent,which was achieved by introducing photoresponsive azobenzene derivatives with cis/trans isomers to Ce-doped mesoporous silica.These photoresponsive groups serve as “molecular switches”by sheltering and exposing active sites,leading to efficient adsorption and desorption.Ce is also doped to provide additional active sites in order to enhance the adsorption performance.The results show that the cis isomers effectively shelter the active sites,leading to the selective adsorption of methylene blue(MB)over brilliant blue(BB),while the trans isomers completely expose the active sites,resulting in the convenient release of the adsorbates.Both selective adsorption and efficient desorption can be realized controllably by these smart adsorbents through photostimulation.Moreover,the performance of the obtained materials is well maintained after five cycles.展开更多
This study examines the impact of different CO<sub>2</sub> injection methods on coalbed methane recovery. Specifically, this study investigated the effectiveness of continuously injecting CO<sub>2<...This study examines the impact of different CO<sub>2</sub> injection methods on coalbed methane recovery. Specifically, this study investigated the effectiveness of continuously injecting CO<sub>2</sub> versus injecting CO<sub>2</sub> that had been soaked for two weeks. The objective was to ascertain which approach was more successful in enhancing CO<sub>2</sub> Enhanced coalbed Methane (CO<sub>2</sub>-ECBM). The experiment involved injecting 3 MPa of CH<sub>4</sub> into dry coal samples, allowing it to adsorb until reaching equilibrium, and then injecting 5 MPa of CO<sub>2</sub> to recover adsorbed CH<sub>4</sub>. The continuous method recovered CH<sub>4</sub> without detectable effluent concentration for 5 hours, but desorption efficiency was only 26% due to fast flow. On the other hand, the desorption efficiency of the cyclic method was only 12%, indicating trapped CH<sub>4</sub>. A comparison of desorption efficiency per unit of time shows the continuous method is more effective than the cyclic method. The results of this study demonstrate the continuous method is more effective for the desorption of CH<sub>4</sub>, and its efficiency can be improved by briefly soaking CO<sub>2</sub> on coal and then reinjecting it to maximize CH<sub>4</sub> recovery. It is advisable to limit the soaking time to prevent excessive swelling of the coal matrix, which can hinder seam flow and harm long-term gas production.展开更多
Sulfate adsorption by poly（m-phenylenediamine）s（PmPDs） with various oxidation states synthesized through chemically oxidative polymerization was investigated.Series of sorption experiments were conducted,and the a...Sulfate adsorption by poly（m-phenylenediamine）s（PmPDs） with various oxidation states synthesized through chemically oxidative polymerization was investigated.Series of sorption experiments were conducted,and the adsorption mechanism and the relationship between oxidation state and adsorption performance were studied with the characterization of Fourier transform infrared spectroscopy（FTIR）,X-ray photoelectron spectroscopy（XPS）,pH tracking and energy calculation.The results show that the adsorption performance in acidic solution is improved with the decrease of oxidation state of poly（m-phenylenediamine）（PmPD）.The rate constant is as high as 425.5 mg/（g·min） in the short equilibrium time of 30 min.The estimated highest adsorptivity of sulfate ions is 95.1%.According to the Langmuir equation,the adsorbance is 108.5 mg/g.The sulfate desorption efficiency is about 95% and the accumulative adsorbance is up to 487.95 mg/g in 5 cycles.展开更多
Using a sonochemical reactor designed by the authors,the process of removing sulfur dioxide from cit- rate solution simulating the flue gas desulfurization was studied.The influence of ultrasonic frequency,ultrasonic ...Using a sonochemical reactor designed by the authors,the process of removing sulfur dioxide from cit- rate solution simulating the flue gas desulfurization was studied.The influence of ultrasonic frequency,ultrasonic power,reaction temperature,stirring speed,inert gases,initial concentration of sulfur dioxide and concentration of citrate on the efficiency of sulfur dioxide desorption,the stability of citrate solution and the concentration of sulfate radical was examined systematically.By comparing the desorption of sulfur dioxide with and without ultrasonifica- tion,it was concluded that(1)lower ultrasonic frequency results in a better degassing efficiency;(2)the use of ul- trasonification in desorbing sulfur dioxide from citrate solution improves the desorbing efficiency in some condi- tions,without changing the essence of chemical reactions;(3)sparging inert gas into the liquid can lower the vis- cosity of solution and the cavitating threshold,and raise the desorption efficiency.These results demonstrate a technical way for deep desorption of sulfur dioxide and provide the fundamental data for future industrial disposal of sulfur dioxide.展开更多
基金supported by the China Scholarship Council(No.201908505143)the Chongqing Research Program of Basic Research and Frontier Technology(No.cstc2017jcyj AX0290/No.cstc2018jcyj AX0563)。
文摘Knowing methane desorption characteristics is essential to define the contribution of adsorbed gas to gas well production.To evaluate the synthetic effect of a clay stabilizer solution on methane desorption kinetics and isotherms pertaining to Longmaxi shale,an experimental setup was designed based on the volumetric method.The objective was to conduct experiments on methane adsorption and desorption kinetics and isotherms before and after clay stabilizer treatments.The experimental data were a good fit for both the intraparticle diffusion model and the Freundlich isotherm model.We analyzed the effect of the clay stabilizer on desorption kinetics and isotherms.Results show that clay stabilizer can obviously improve the diffusion rate constant and reduce the methane adsorption amount.Moreover,we analyzed the desorption efficiency before and after treatment as well as the adsorbed methane content.The results show that a higher desorption efficiency after treatment can be observed when the pressure is higher than 6.84 MPa.Meanwhile,the adsorbed methane content before and after treatment all increase when the pressure decreases,and clay stabilizer can obviously promote the adsorbed methane to free gas when the pressure is lower than 19 MPa.This can also be applied to the optimization formulation of slickwater and the design of gas well production.
基金This work was supported by the National Science Fund for Excellent Young Scholars(21722606)the National Natural Science Foundation of China(21676138,21878149,21808110,and 21576137)+1 种基金the China Postdoctoral Science Foundation(2018M632295)the Six Talent Plan(2016XCL031).
文摘Achieving efficient adsorption and desorption processes by controllably tuning the properties of adsorbents at different technical stages is extremely attractive.However,it is difficult for traditional adsorbents to reach the target because of their fixed active sites.Herein,we report on the fabrication of a smart adsorbent,which was achieved by introducing photoresponsive azobenzene derivatives with cis/trans isomers to Ce-doped mesoporous silica.These photoresponsive groups serve as “molecular switches”by sheltering and exposing active sites,leading to efficient adsorption and desorption.Ce is also doped to provide additional active sites in order to enhance the adsorption performance.The results show that the cis isomers effectively shelter the active sites,leading to the selective adsorption of methylene blue(MB)over brilliant blue(BB),while the trans isomers completely expose the active sites,resulting in the convenient release of the adsorbates.Both selective adsorption and efficient desorption can be realized controllably by these smart adsorbents through photostimulation.Moreover,the performance of the obtained materials is well maintained after five cycles.
文摘This study examines the impact of different CO<sub>2</sub> injection methods on coalbed methane recovery. Specifically, this study investigated the effectiveness of continuously injecting CO<sub>2</sub> versus injecting CO<sub>2</sub> that had been soaked for two weeks. The objective was to ascertain which approach was more successful in enhancing CO<sub>2</sub> Enhanced coalbed Methane (CO<sub>2</sub>-ECBM). The experiment involved injecting 3 MPa of CH<sub>4</sub> into dry coal samples, allowing it to adsorb until reaching equilibrium, and then injecting 5 MPa of CO<sub>2</sub> to recover adsorbed CH<sub>4</sub>. The continuous method recovered CH<sub>4</sub> without detectable effluent concentration for 5 hours, but desorption efficiency was only 26% due to fast flow. On the other hand, the desorption efficiency of the cyclic method was only 12%, indicating trapped CH<sub>4</sub>. A comparison of desorption efficiency per unit of time shows the continuous method is more effective than the cyclic method. The results of this study demonstrate the continuous method is more effective for the desorption of CH<sub>4</sub>, and its efficiency can be improved by briefly soaking CO<sub>2</sub> on coal and then reinjecting it to maximize CH<sub>4</sub> recovery. It is advisable to limit the soaking time to prevent excessive swelling of the coal matrix, which can hinder seam flow and harm long-term gas production.
基金Project(50925417) supported by China National Funds for Distinguished Young ScientistsProject(50830301) supported by the National Natural Science Foundation of China+1 种基金Project(2009ZX07212-001-01) supported by Major Science and Technology Program for Water Pollution Control and Treatment of ChinaProject(2011) supported by Hunan Nonferrous Fundamental Research Fund
文摘Sulfate adsorption by poly（m-phenylenediamine）s（PmPDs） with various oxidation states synthesized through chemically oxidative polymerization was investigated.Series of sorption experiments were conducted,and the adsorption mechanism and the relationship between oxidation state and adsorption performance were studied with the characterization of Fourier transform infrared spectroscopy（FTIR）,X-ray photoelectron spectroscopy（XPS）,pH tracking and energy calculation.The results show that the adsorption performance in acidic solution is improved with the decrease of oxidation state of poly（m-phenylenediamine）（PmPD）.The rate constant is as high as 425.5 mg/（g·min） in the short equilibrium time of 30 min.The estimated highest adsorptivity of sulfate ions is 95.1%.According to the Langmuir equation,the adsorbance is 108.5 mg/g.The sulfate desorption efficiency is about 95% and the accumulative adsorbance is up to 487.95 mg/g in 5 cycles.
基金Supported by the National Natural Science Foundation of China （No.50244012） and the Natural Science Foundation of Shaanxi Education Department （No.02JC37）.
文摘Using a sonochemical reactor designed by the authors,the process of removing sulfur dioxide from cit- rate solution simulating the flue gas desulfurization was studied.The influence of ultrasonic frequency,ultrasonic power,reaction temperature,stirring speed,inert gases,initial concentration of sulfur dioxide and concentration of citrate on the efficiency of sulfur dioxide desorption,the stability of citrate solution and the concentration of sulfate radical was examined systematically.By comparing the desorption of sulfur dioxide with and without ultrasonifica- tion,it was concluded that(1)lower ultrasonic frequency results in a better degassing efficiency;(2)the use of ul- trasonification in desorbing sulfur dioxide from citrate solution improves the desorbing efficiency in some condi- tions,without changing the essence of chemical reactions;(3)sparging inert gas into the liquid can lower the vis- cosity of solution and the cavitating threshold,and raise the desorption efficiency.These results demonstrate a technical way for deep desorption of sulfur dioxide and provide the fundamental data for future industrial disposal of sulfur dioxide.
