As CO2 is injected into pore spaces of water-filled reservoir rocks, it displaces much of the pore fluids. In short terms (several to tens of years), the greater part of the injected CO2 is predicted to stay as free C...As CO2 is injected into pore spaces of water-filled reservoir rocks, it displaces much of the pore fluids. In short terms (several to tens of years), the greater part of the injected CO2 is predicted to stay as free CO2 , i.e. in a CO2 rich dense phase that may contain some water. This paper investigates the sorption characteristics for rocks (quartzose arenite, greywacke, shale, granite and serpentine) and minerals (quartz and albite) in the CO2 rich dense phase. The measurements were conducted at 50°C and 100°C, and pressures up to 20 MPa. Our results demonstrated that significant quantities of CO2 were sorbed with all the samples. Particularly, at 50°C and 100°C, quartzose arenite showed largest sorption capacity among the other samples in higher pressures (>10 MPa). Furthermore, comparison with model prediction based on the pore filling model, which assumed that CO2 acts as filling pore spaces of the rocks and minerals, suggested the importance of the sorption mechanism in the CO2 geological storage in addition to the pore-filling mechanism. The present results should be pointed out that the sorption characteristics may have significant and meaningful effect on the assessment of CO2 storage capacity in geological media.展开更多
The increasing use of petroleum-derived fuels over the last few decades has subsequently augmented the risk of spills in the environment. Soil pollution with petroleum hydrocarbons(principally caused by leaks in pipel...The increasing use of petroleum-derived fuels over the last few decades has subsequently augmented the risk of spills in the environment. Soil pollution with petroleum hydrocarbons(principally caused by leaks in pipelines and underground storage tanks) is one of the major sources of soil degradation. Once in soil, fuel hydrocarbons suffer from a wide variety of multiphase processes including transport(advection, diffusion, and dispersion) among and within phases(aqueous and non-aqueous liquid, gas, and soil solids), mass transfer among phases(volatilization, sorption, and solution), and other natural attenuation processes, such as biodegradation and plant uptake and metabolism. This review identifies and describes the major processes occurring in soil that have a significant influence on the environmental fate of petroleum hydrocarbons. The definition of the processes involved in pollutant migration and distribution in soil and the formulation of adequate equations using accurate parameters(e.g., diffusion coefficients, velocity of advective flows, and mass transfer coefficients) will allow prediction of the final fate of soil pollutants. In addition to transport and mass transfer processes,which are more widely studied, the incorporation of attenuation mechanisms driven by microorganisms and plants is essential to predict the final concentration of the pollutants in the whole multiphase scenario. This work underlines the importance of the determination of accurate parameters through the performance of laboratory and/or field-scale experiments to develop precise pollutant migration models.展开更多
The optimal condition for a one-step process removing organic compounds from coking wastewater by simultaneously synthesized organobentonite as a pretreatment was investigated.Results showed that sorption of organic c...The optimal condition for a one-step process removing organic compounds from coking wastewater by simultaneously synthesized organobentonite as a pretreatment was investigated.Results showed that sorption of organic compounds by organobentonite was positively correlated to the cation surfactant exchange on the bentonite and the octanol-water partition coefficient（Kow） of the solutes.With 0.75 g/L bentonite and 180 mg/L（60% of bentonite cation exchange capacity） cetyltrimethylammonium bromide,the removal efficiencies of the 16 polycyclic aromatic hydrocarbon（PAHs） specified by the US Environmental Protection Agency in coking wastewater except naphthalene were more than 90%,and that of benzo（a）pyrene was 99.5%.At the same time,the removal efficiencies of CODCr,NH3-N,volatile phenols,colour and turbidity were 28.6%,13.2%,8.9%,55% and 84.3%,respectively,and the ratio of BOD5/CODCr increased from 0.31 to 0.41.These results indicated that the one-step process had high removal efficiency for toxic and refractory hydrophobic organic compounds,and could improve the biodegradability of the coking wastewater.Therefore it could be a promising technology for the pretreatment of toxic and refractory organic wastewater.展开更多
A theoretical study has been conducted to investigate the effects of mass transfer on heat transfer in moisture exchange across a membrane and a mathematical model describing the heat transfer process with considerati...A theoretical study has been conducted to investigate the effects of mass transfer on heat transfer in moisture exchange across a membrane and a mathematical model describing the heat transfer process with consideration of the heat of sorption was established. A dimensionless variable, Ψ =JLλ /δ (T <SUB>10</SUB>−T <SUB>20</SUB>), which controls the effect of the heat of sorption on the heat transfer in membrane process, was obtained through theoretical analysis, and the effects of Ψ on the heat transfer process were analyzed. Results showed that in the case that the temperature gradient and mass transfer are in the same direction, the effective heat flux changes the direction at Ψ=1. For Ψ【1, the heat transfers from high to low temperature sides through the membrane, and the total thermal resistance increases with increasing the moisture flux across membrane or reducing the temperature difference between the bulk flows on the two sides of membrane. For Ψ】1, the overall effect of the heat and mass transfer is that the effective heat flux points from low to high temperature sides and the total thermal resistance decreases with increasing the mass flux or reducing the temperature difference. In the case that the temperature gradient and mass transfer are in the opposite directions, the existence of the heat of sorption acts to enhance the heat transfer from high to low temperature sides, causing a reduced total thermal resistance, and the greater the mass flux or the smaller the temperature difference, the smaller the total thermal resistance.展开更多
In this study, we developed a three-stage catalyst-adsorbent reactor for the catalytic hydrolysis of CF4. Each stage is composed of a catalyst bed followed by an adsorbent bed using Ca（OH）2 to remove HF. The three s...In this study, we developed a three-stage catalyst-adsorbent reactor for the catalytic hydrolysis of CF4. Each stage is composed of a catalyst bed followed by an adsorbent bed using Ca（OH）2 to remove HF. The three stages are connected in series to enhance the hydrolysis of CF4 and eliminate a scrubber to dissolve HF in water at the same time. With a 10 wt-% Ce/AlaO3 catalyst prepared by the incipient wetness method using boehmite and a granular calcium hydroxide as an adsorbent, the CF4 conversion in our proposed reactor was 7%-23% higher than that in a conventional single-bed catalytic reactor in the temperature range of 923-1023 K. In addition, experimental and numerical simulation （Aspen HYSYS） results showed a reasonable trend of increased CF4 conversion with the adsorbent added and these results can be used as a useful design guideline for our newly proposed multistage reactor system.展开更多
文摘As CO2 is injected into pore spaces of water-filled reservoir rocks, it displaces much of the pore fluids. In short terms (several to tens of years), the greater part of the injected CO2 is predicted to stay as free CO2 , i.e. in a CO2 rich dense phase that may contain some water. This paper investigates the sorption characteristics for rocks (quartzose arenite, greywacke, shale, granite and serpentine) and minerals (quartz and albite) in the CO2 rich dense phase. The measurements were conducted at 50°C and 100°C, and pressures up to 20 MPa. Our results demonstrated that significant quantities of CO2 were sorbed with all the samples. Particularly, at 50°C and 100°C, quartzose arenite showed largest sorption capacity among the other samples in higher pressures (>10 MPa). Furthermore, comparison with model prediction based on the pore filling model, which assumed that CO2 acts as filling pore spaces of the rocks and minerals, suggested the importance of the sorption mechanism in the CO2 geological storage in addition to the pore-filling mechanism. The present results should be pointed out that the sorption characteristics may have significant and meaningful effect on the assessment of CO2 storage capacity in geological media.
基金supported by the European Regional Development Fund (ERDF) Interreg Sudoe Program (No. PhytoSUDOE401-SOE1/P5/E0189)the Galician government (Agrupación Estratéxica CRETUS+1 种基金 No. 402 AGRU2015/02)a postdoctoral fellowship (No. ED481B 2017/073) granted to Dr. Balseiro-Romero by the Consellería de Cultura, Educacióne Ordenación Universitaria (Xunta de Galicia, Spain)
文摘The increasing use of petroleum-derived fuels over the last few decades has subsequently augmented the risk of spills in the environment. Soil pollution with petroleum hydrocarbons(principally caused by leaks in pipelines and underground storage tanks) is one of the major sources of soil degradation. Once in soil, fuel hydrocarbons suffer from a wide variety of multiphase processes including transport(advection, diffusion, and dispersion) among and within phases(aqueous and non-aqueous liquid, gas, and soil solids), mass transfer among phases(volatilization, sorption, and solution), and other natural attenuation processes, such as biodegradation and plant uptake and metabolism. This review identifies and describes the major processes occurring in soil that have a significant influence on the environmental fate of petroleum hydrocarbons. The definition of the processes involved in pollutant migration and distribution in soil and the formulation of adequate equations using accurate parameters(e.g., diffusion coefficients, velocity of advective flows, and mass transfer coefficients) will allow prediction of the final fate of soil pollutants. In addition to transport and mass transfer processes,which are more widely studied, the incorporation of attenuation mechanisms driven by microorganisms and plants is essential to predict the final concentration of the pollutants in the whole multiphase scenario. This work underlines the importance of the determination of accurate parameters through the performance of laboratory and/or field-scale experiments to develop precise pollutant migration models.
基金supported by the National Natural Science Foundation of China (No. 20890111)
文摘The optimal condition for a one-step process removing organic compounds from coking wastewater by simultaneously synthesized organobentonite as a pretreatment was investigated.Results showed that sorption of organic compounds by organobentonite was positively correlated to the cation surfactant exchange on the bentonite and the octanol-water partition coefficient（Kow） of the solutes.With 0.75 g/L bentonite and 180 mg/L（60% of bentonite cation exchange capacity） cetyltrimethylammonium bromide,the removal efficiencies of the 16 polycyclic aromatic hydrocarbon（PAHs） specified by the US Environmental Protection Agency in coking wastewater except naphthalene were more than 90%,and that of benzo（a）pyrene was 99.5%.At the same time,the removal efficiencies of CODCr,NH3-N,volatile phenols,colour and turbidity were 28.6%,13.2%,8.9%,55% and 84.3%,respectively,and the ratio of BOD5/CODCr increased from 0.31 to 0.41.These results indicated that the one-step process had high removal efficiency for toxic and refractory hydrophobic organic compounds,and could improve the biodegradability of the coking wastewater.Therefore it could be a promising technology for the pretreatment of toxic and refractory organic wastewater.
基金the National Natural Science Foundation of China(Grant No.50576040)
文摘A theoretical study has been conducted to investigate the effects of mass transfer on heat transfer in moisture exchange across a membrane and a mathematical model describing the heat transfer process with consideration of the heat of sorption was established. A dimensionless variable, Ψ =JLλ /δ (T <SUB>10</SUB>−T <SUB>20</SUB>), which controls the effect of the heat of sorption on the heat transfer in membrane process, was obtained through theoretical analysis, and the effects of Ψ on the heat transfer process were analyzed. Results showed that in the case that the temperature gradient and mass transfer are in the same direction, the effective heat flux changes the direction at Ψ=1. For Ψ【1, the heat transfers from high to low temperature sides through the membrane, and the total thermal resistance increases with increasing the moisture flux across membrane or reducing the temperature difference between the bulk flows on the two sides of membrane. For Ψ】1, the overall effect of the heat and mass transfer is that the effective heat flux points from low to high temperature sides and the total thermal resistance decreases with increasing the mass flux or reducing the temperature difference. In the case that the temperature gradient and mass transfer are in the opposite directions, the existence of the heat of sorption acts to enhance the heat transfer from high to low temperature sides, causing a reduced total thermal resistance, and the greater the mass flux or the smaller the temperature difference, the smaller the total thermal resistance.
文摘采用AB-8大孔树脂吸附分离橄榄油加工废液中的橄榄多酚。分别考察了静态吸附、静态解吸和动态洗脱工艺条件。结果表明:适宜的静态吸附条件为在30℃下用1.5 g预处理的树脂吸附20 m L橄榄多酚质量浓度为1.52 mg/m L的粗提稀释液,吸附3 h时吸附量可达14.43 mg/g;动态洗脱橄榄多酚的适宜条件为洗脱流速1.0 m L/min,依次用蒸馏水、70%乙醇溶液、90%乙醇溶液进行分段洗脱。在静态吸附和动态分段洗脱的组合条件下,纯化所得橄榄多酚的纯度为56.44%,为粗提稀释液的7.93倍。
文摘In this study, we developed a three-stage catalyst-adsorbent reactor for the catalytic hydrolysis of CF4. Each stage is composed of a catalyst bed followed by an adsorbent bed using Ca（OH）2 to remove HF. The three stages are connected in series to enhance the hydrolysis of CF4 and eliminate a scrubber to dissolve HF in water at the same time. With a 10 wt-% Ce/AlaO3 catalyst prepared by the incipient wetness method using boehmite and a granular calcium hydroxide as an adsorbent, the CF4 conversion in our proposed reactor was 7%-23% higher than that in a conventional single-bed catalytic reactor in the temperature range of 923-1023 K. In addition, experimental and numerical simulation （Aspen HYSYS） results showed a reasonable trend of increased CF4 conversion with the adsorbent added and these results can be used as a useful design guideline for our newly proposed multistage reactor system.
