Carbon dioxide （CO2） enhanced coalbed methane （ECBM） is an effective method to im- prove methane （CH4） production and this technology has already been used to increase gas production in several field trials worl...Carbon dioxide （CO2） enhanced coalbed methane （ECBM） is an effective method to im- prove methane （CH4） production and this technology has already been used to increase gas production in several field trials worldwide. One major problem is the injection drop in the later period due to permeability decrease caused by coal matrix swelling induced by CO2 injection. In order to quantify the swelling effect, in this work, coal samples were collected from the Bulli coal seam, Sydney Basin and adsorption tests with simultaneous matrix swelling measurement were conducted. The adsorption and swelling characteristics were analyzed by measuring the adsorption mass simultaneously with the strain measurement. Then experiments were conducted to replicate the ECBM process using the indi- rect gravity method to obtain the swelfing strain change with CO2 injection. The results show that the coal adsorption capacity in CO2 is almost two times greater than that in CH4, and nitrogen adsorption is the least among these gases. A Langmuir-fike model can be used to describe the strain with the gas pressure and the swelling strain induced by gas adsorption has a Hnear relationship with gas adsorp- tion quantity. Moreover, swelling strain increase was observed when CO2 was injected into the sample cell and the swelling strain was almost the sum of the strains induced by different gases at correspond- ing partial gas pressure.展开更多
Precipitation or dissolution due to geochemical reactions has been observed in the caprocks for CO_(2)geosequestration.Geochemical reactions modify the caprock sealing efficiency with self-limiting or self-enhancement...Precipitation or dissolution due to geochemical reactions has been observed in the caprocks for CO_(2)geosequestration.Geochemical reactions modify the caprock sealing efficiency with self-limiting or self-enhancement.However,the effect of this modification on the caprock sealing efficiency has not been fully investigated through multiphysical-geochemical coupling analysis.In this study,a multiphysical-geochemical coupling model was proposed to analyze caprock sealing efficiency.This coupling model considered the full couplings of caprock deformation,two-phase flow,CO_(2)concentration diffusion,geochemical reaction,and CO_(2)sorption.The two-phase flow only occurs in the fracture network and the CO_(2)may partially dissolve into water and diffuse through the concentration difference.The dissolved CO_(2)has geochemical reactions with some critical minerals,thus altering flow channels.The CO_(2)in the fracture network diffuses into matrix,causing the matrix swelling.This fully coupling model was validated with a penetration experiment on a cement cube and compared with two other models for CO_(2)storage plumes.Finally,the effects of geochemical reactions on penetration depth and pore pressure were studied through parametric study.The numerical simulations reveal that the coupling of geochemical reactions and matrix diffusion significantly affect the caprock sealing efficiency.Geochemical reactions occur at a short time after the arrival of CO_(2)concentration and modify the fracture porosity.The CO_(2)diffusion into the matrix requires a much longer time and mainly induces matrix swelling.These effects may produce selfenhancement or self-limiting depending on the flow rate in the fracture network,thus significantly modifying caprock sealing efficiency.展开更多
Macrofungi have been advocated to be a promising remediation material for heavy metal pollution. This study aimed to screen for cadmium(Cd)-tolerant oyster mushroom strains which may be used as biomaterials for Cd rem...Macrofungi have been advocated to be a promising remediation material for heavy metal pollution. This study aimed to screen for cadmium(Cd)-tolerant oyster mushroom strains which may be used as biomaterials for Cd remediation in North China. To this end, 43 oyster mushroom strains were collected across North China and subject to Cd inhibition test. Phylogenetic affiliation of the tolerant strains was identified using molecular fingerprinting, and representative Cd-tolerant strains were characterized in terms of their Cd sorption capacity. Two strains, JINONG21 and SUYIN6 affiliated with Pleurotus ostreatus, were found to be highly tolerant to Cd, with a minimal inhibitory concentration of 4 mg L^(-1) Cd and a maximal tolerant concentration of 80 mg L^(-1) Cd under the test conditions. Meanwhile, JINONG21 and SUYIN6 were able to absorb up to 676 mg kg^(-1) and 970 mg kg^(-1) Cd in their mycelia in the culture medium with 20 mg L^(-1) Cd, respectively. In conclusion, the P. ostreatus strains identified in this study presented an outstanding capacity of Cd tolerance and sorption and could be promising biomaterials for Cd remediation in North China.展开更多
基金supported by the Australian Coal Industry’s Research Program ( No. ACARP C24019)the National Natural Science Foundation of China (No. 51604153)the National Science and Technology Major Project (No. 2016ZX05045-004-006)
文摘Carbon dioxide （CO2） enhanced coalbed methane （ECBM） is an effective method to im- prove methane （CH4） production and this technology has already been used to increase gas production in several field trials worldwide. One major problem is the injection drop in the later period due to permeability decrease caused by coal matrix swelling induced by CO2 injection. In order to quantify the swelling effect, in this work, coal samples were collected from the Bulli coal seam, Sydney Basin and adsorption tests with simultaneous matrix swelling measurement were conducted. The adsorption and swelling characteristics were analyzed by measuring the adsorption mass simultaneously with the strain measurement. Then experiments were conducted to replicate the ECBM process using the indi- rect gravity method to obtain the swelfing strain change with CO2 injection. The results show that the coal adsorption capacity in CO2 is almost two times greater than that in CH4, and nitrogen adsorption is the least among these gases. A Langmuir-fike model can be used to describe the strain with the gas pressure and the swelling strain induced by gas adsorption has a Hnear relationship with gas adsorp- tion quantity. Moreover, swelling strain increase was observed when CO2 was injected into the sample cell and the swelling strain was almost the sum of the strains induced by different gases at correspond- ing partial gas pressure.
基金National Natural Science Foundation of China,Grant/Award Number:51674246Creative Research and Development Group Program of Jiangsu Province,Grant/Award Number:2014-27。
文摘Precipitation or dissolution due to geochemical reactions has been observed in the caprocks for CO_(2)geosequestration.Geochemical reactions modify the caprock sealing efficiency with self-limiting or self-enhancement.However,the effect of this modification on the caprock sealing efficiency has not been fully investigated through multiphysical-geochemical coupling analysis.In this study,a multiphysical-geochemical coupling model was proposed to analyze caprock sealing efficiency.This coupling model considered the full couplings of caprock deformation,two-phase flow,CO_(2)concentration diffusion,geochemical reaction,and CO_(2)sorption.The two-phase flow only occurs in the fracture network and the CO_(2)may partially dissolve into water and diffuse through the concentration difference.The dissolved CO_(2)has geochemical reactions with some critical minerals,thus altering flow channels.The CO_(2)in the fracture network diffuses into matrix,causing the matrix swelling.This fully coupling model was validated with a penetration experiment on a cement cube and compared with two other models for CO_(2)storage plumes.Finally,the effects of geochemical reactions on penetration depth and pore pressure were studied through parametric study.The numerical simulations reveal that the coupling of geochemical reactions and matrix diffusion significantly affect the caprock sealing efficiency.Geochemical reactions occur at a short time after the arrival of CO_(2)concentration and modify the fracture porosity.The CO_(2)diffusion into the matrix requires a much longer time and mainly induces matrix swelling.These effects may produce selfenhancement or self-limiting depending on the flow rate in the fracture network,thus significantly modifying caprock sealing efficiency.
基金financially supported by the "Hundred Talents Program" of the "Pioneer Initiative" of Chinese Academy of Sciences
文摘Macrofungi have been advocated to be a promising remediation material for heavy metal pollution. This study aimed to screen for cadmium(Cd)-tolerant oyster mushroom strains which may be used as biomaterials for Cd remediation in North China. To this end, 43 oyster mushroom strains were collected across North China and subject to Cd inhibition test. Phylogenetic affiliation of the tolerant strains was identified using molecular fingerprinting, and representative Cd-tolerant strains were characterized in terms of their Cd sorption capacity. Two strains, JINONG21 and SUYIN6 affiliated with Pleurotus ostreatus, were found to be highly tolerant to Cd, with a minimal inhibitory concentration of 4 mg L^(-1) Cd and a maximal tolerant concentration of 80 mg L^(-1) Cd under the test conditions. Meanwhile, JINONG21 and SUYIN6 were able to absorb up to 676 mg kg^(-1) and 970 mg kg^(-1) Cd in their mycelia in the culture medium with 20 mg L^(-1) Cd, respectively. In conclusion, the P. ostreatus strains identified in this study presented an outstanding capacity of Cd tolerance and sorption and could be promising biomaterials for Cd remediation in North China.
