Steam-reforming is an effective approach for upgrading methane and hydrocarbon of coke-oven gas into CO and HE, but the kinetic behavior needs more study. We investigated the conversion of methane in coke-oven gas by ...Steam-reforming is an effective approach for upgrading methane and hydrocarbon of coke-oven gas into CO and HE, but the kinetic behavior needs more study. We investigated the conversion of methane in coke-oven gas by steam reforming process in an electric tubular flow at 14 kPa with temperature varying from .500 ℃ to 9.50 ℃, and developed a kenetic model for, ignoring the effects of adsorption and diffusion. The optimal dynamic conditions for methane conversion 14 kPa are as follows： the ratio of the amount of water to the amount of methane is from 1.1 to 1.3; the reaction temperature is from 1 223 K to 1 273 K. The methane conversion rate is larger than 95% when the ratio of the amount of water to the amount of methane is 1.2 at a temperature above 1 223 K with the residence time up to 0.75 s.展开更多
We evaluated the phenology and litterfall dynamics of the mangrove Bruguiera gymnorrhiza（L.）Lamk along the Okukubi River, Okinawa Island, Japan.Over 3 years, this species showed the highest litterfall of leaves and ...We evaluated the phenology and litterfall dynamics of the mangrove Bruguiera gymnorrhiza（L.）Lamk along the Okukubi River, Okinawa Island, Japan.Over 3 years, this species showed the highest litterfall of leaves and stipules in summer and the lowest litterfall in winter. From Kendall＇s coefficient of concordance, the monthly changes in leaf, stipule, and branch were strongly and significantly concordant among years. Leaf and stipule litterfall could be governed by monthly maximum wind speed, monthly day length, and monthly mean air temperature. Branch litterfall depended on monthly maximum wind speed and monthly rainfall, and increased exponentially with increasing monthly maximum wind speed. Mean total litterfall was 11.8 Mg ha^（-1）yr^（-1）, with the largest component being leaf litterfall（65.8 %）. Annual leaf litterfall per plot was almost constant regardless of the tree density of the plot. Mean leaf longevity was 18 months.Flower and mature propagule litterfall might be influenced by monthly mean air temperature, monthly day length and monthly mean air temperature. The average development periods from flower buds to flowers and flower buds to mature propagules were 1 and 8 months, respectively.Except for leaf and branch, all vegetative and reproductive organ litterfall had clear annual cycles. B. gymnorrhiza showed a positive correlation between leaf production and reproductive organ production.展开更多
Dielectric barrier discharge（DBD） is utilized to decompose xylene vapor in mobile gas under normal atmospheric pressure.The plasma is generated by an AC power source with a frequency of 6 kHz.In the experiment,the d...Dielectric barrier discharge（DBD） is utilized to decompose xylene vapor in mobile gas under normal atmospheric pressure.The plasma is generated by an AC power source with a frequency of 6 kHz.In the experiment,the discharge power on the DBD reactor was calculated by a Lissajous figure,and the specific input energy（SIE） of different discharge voltage or residence time was obtained.The concentrations of xylene,carbon monoxide and carbon dioxide in the gas were analyzed by gas chromatography.The spectra of DBD were diagnosed using a spectrometer.We calculated the conversion rate（CR）,mineralization rate（MR） and carbon dioxide selectivity.The relationship between these quantities and the SIE was analyzed.The experimental results show that high concentration xylene can be decomposed mostly by DBD plasma.The CR can reach as high as 90%with the main product of carbon dioxide.展开更多
A DBD-type （dielectric barrier discharge） NTP （non-thermal plasma） reactor was designed and an experimental system was established, in order to study the mechanism of plasma chemistry reactions in a gas mixture of...A DBD-type （dielectric barrier discharge） NTP （non-thermal plasma） reactor was designed and an experimental system was established, in order to study the mechanism of plasma chemistry reactions in a gas mixture of C3H6/NO/O2/N2. This paper is focused on a. the effects of the initial concentrations of both NO and 02 upon NO conversion rate and the variations of NOx and 03 concentrations versus SED （specific energy density） when mixed gases of NO/O2/N2 passed the NTP reactor; b. the effects of the initial concentration of C3H6 upon NO oxidation and reduction reactions in mixed gases of NO/N2/CaH6 and NO/N2/O2/C3H6. The conclusions drawn are as follows, a. When the mixed gases of NO/O2/N2 passed the NTP reactor, NO was simultaneously involved in oxidation and reduction reactions with the former dominant and NO2 concentration increased at the NTP reactor outlet. The NO conversion rate decreased with the increase of the initial concentration of NO and 02, the O3 concentration firstly increased and then decreased with the increase in SED value, b. NO reduction reaction was very weak and energy consumption was very high in a mixed gases of NO/N2. However, when C3H6 was added, the NO conversion rate was significantly increased. When 63H6 was added to the mixed gases of NO/O2/N2, the NO conversion rate was significantly increased and the energy consumption was considerably reduced.展开更多
The properties and structural changes of unconverted oil(UCO)obtained from ebullated bed hydrogenation at different residue conversion rates were analyzed to clarify the reaction process of heavy components.Meanwhile,...The properties and structural changes of unconverted oil(UCO)obtained from ebullated bed hydrogenation at different residue conversion rates were analyzed to clarify the reaction process of heavy components.Meanwhile,the processing routes of UCO,delayed coking,and solvent deasphalting,were investigated.The results showed that with the increase of conversion,the impurity removal rate increased;meanwhile the contents of sulfur and metal in UCO decreased,while the contents of nitrogen and residual carbon increased,and the colloidal stability of UCO became worse.The structural parameters of UCO indicated that the change in molecular structure of heavy oil mainly covered the opening of cycloalkanes ring,hydrogenation saturation of aromatic rings and dealkylation reaction during hydrogenation in the ebullated bed;the aromatic structure was basically unchanged at high conversion,and was mainly due to the ring opening of cycloalkanes and the fracture reaction of alkyl side chains.The coking route of UCO showed that low sulfur petroleum coke with different grades could be prepared by adjusting the conversion in ebullated bed to produce UCOs with different properties.The coke generating coefficient and sulfur transfer coefficient in UCO coking process were higher than those in residue coking.The properties of deasphalted oil(DAO)of UCO were significantly improved and could be used as FCC or hydrocracking feedstock.The DAO yield of UCO feedstock at high conversion was higher,and its sulfur content was lower and CCR value was higher.展开更多
基金the Postdoctoral Foundation of China under the grant No. 2910001
文摘Steam-reforming is an effective approach for upgrading methane and hydrocarbon of coke-oven gas into CO and HE, but the kinetic behavior needs more study. We investigated the conversion of methane in coke-oven gas by steam reforming process in an electric tubular flow at 14 kPa with temperature varying from .500 ℃ to 9.50 ℃, and developed a kenetic model for, ignoring the effects of adsorption and diffusion. The optimal dynamic conditions for methane conversion 14 kPa are as follows： the ratio of the amount of water to the amount of methane is from 1.1 to 1.3; the reaction temperature is from 1 223 K to 1 273 K. The methane conversion rate is larger than 95% when the ratio of the amount of water to the amount of methane is 1.2 at a temperature above 1 223 K with the residence time up to 0.75 s.
基金supported by a Grant-in-Aid for Scientific Research(No.23380094)from the Ministry of Education,Culture,Sport,Science and Technology,Japan
文摘We evaluated the phenology and litterfall dynamics of the mangrove Bruguiera gymnorrhiza（L.）Lamk along the Okukubi River, Okinawa Island, Japan.Over 3 years, this species showed the highest litterfall of leaves and stipules in summer and the lowest litterfall in winter. From Kendall＇s coefficient of concordance, the monthly changes in leaf, stipule, and branch were strongly and significantly concordant among years. Leaf and stipule litterfall could be governed by monthly maximum wind speed, monthly day length, and monthly mean air temperature. Branch litterfall depended on monthly maximum wind speed and monthly rainfall, and increased exponentially with increasing monthly maximum wind speed. Mean total litterfall was 11.8 Mg ha^（-1）yr^（-1）, with the largest component being leaf litterfall（65.8 %）. Annual leaf litterfall per plot was almost constant regardless of the tree density of the plot. Mean leaf longevity was 18 months.Flower and mature propagule litterfall might be influenced by monthly mean air temperature, monthly day length and monthly mean air temperature. The average development periods from flower buds to flowers and flower buds to mature propagules were 1 and 8 months, respectively.Except for leaf and branch, all vegetative and reproductive organ litterfall had clear annual cycles. B. gymnorrhiza showed a positive correlation between leaf production and reproductive organ production.
文摘Dielectric barrier discharge（DBD） is utilized to decompose xylene vapor in mobile gas under normal atmospheric pressure.The plasma is generated by an AC power source with a frequency of 6 kHz.In the experiment,the discharge power on the DBD reactor was calculated by a Lissajous figure,and the specific input energy（SIE） of different discharge voltage or residence time was obtained.The concentrations of xylene,carbon monoxide and carbon dioxide in the gas were analyzed by gas chromatography.The spectra of DBD were diagnosed using a spectrometer.We calculated the conversion rate（CR）,mineralization rate（MR） and carbon dioxide selectivity.The relationship between these quantities and the SIE was analyzed.The experimental results show that high concentration xylene can be decomposed mostly by DBD plasma.The CR can reach as high as 90%with the main product of carbon dioxide.
基金supported by National Natural Science Foundation of China (No.50776041)Provincial Science Foundation of Jiangsu of China (BK2008225) Scientific Research Foundation project of Jiangsu University of China (10JDG051)
文摘A DBD-type （dielectric barrier discharge） NTP （non-thermal plasma） reactor was designed and an experimental system was established, in order to study the mechanism of plasma chemistry reactions in a gas mixture of C3H6/NO/O2/N2. This paper is focused on a. the effects of the initial concentrations of both NO and 02 upon NO conversion rate and the variations of NOx and 03 concentrations versus SED （specific energy density） when mixed gases of NO/O2/N2 passed the NTP reactor; b. the effects of the initial concentration of C3H6 upon NO oxidation and reduction reactions in mixed gases of NO/N2/CaH6 and NO/N2/O2/C3H6. The conclusions drawn are as follows, a. When the mixed gases of NO/O2/N2 passed the NTP reactor, NO was simultaneously involved in oxidation and reduction reactions with the former dominant and NO2 concentration increased at the NTP reactor outlet. The NO conversion rate decreased with the increase of the initial concentration of NO and 02, the O3 concentration firstly increased and then decreased with the increase in SED value, b. NO reduction reaction was very weak and energy consumption was very high in a mixed gases of NO/N2. However, when C3H6 was added, the NO conversion rate was significantly increased. When 63H6 was added to the mixed gases of NO/O2/N2, the NO conversion rate was significantly increased and the energy consumption was considerably reduced.
文摘The properties and structural changes of unconverted oil(UCO)obtained from ebullated bed hydrogenation at different residue conversion rates were analyzed to clarify the reaction process of heavy components.Meanwhile,the processing routes of UCO,delayed coking,and solvent deasphalting,were investigated.The results showed that with the increase of conversion,the impurity removal rate increased;meanwhile the contents of sulfur and metal in UCO decreased,while the contents of nitrogen and residual carbon increased,and the colloidal stability of UCO became worse.The structural parameters of UCO indicated that the change in molecular structure of heavy oil mainly covered the opening of cycloalkanes ring,hydrogenation saturation of aromatic rings and dealkylation reaction during hydrogenation in the ebullated bed;the aromatic structure was basically unchanged at high conversion,and was mainly due to the ring opening of cycloalkanes and the fracture reaction of alkyl side chains.The coking route of UCO showed that low sulfur petroleum coke with different grades could be prepared by adjusting the conversion in ebullated bed to produce UCOs with different properties.The coke generating coefficient and sulfur transfer coefficient in UCO coking process were higher than those in residue coking.The properties of deasphalted oil(DAO)of UCO were significantly improved and could be used as FCC or hydrocracking feedstock.The DAO yield of UCO feedstock at high conversion was higher,and its sulfur content was lower and CCR value was higher.
