To get more accurate kinetic data of the absorption of CO2 into aqueous solution of N-methyldiethanolamine,a wetted wall column was modified to more uniformly distribute the liquid on the column surface and gas in the...To get more accurate kinetic data of the absorption of CO2 into aqueous solution of N-methyldiethanolamine,a wetted wall column was modified to more uniformly distribute the liquid on the column surface and gas in the absorbing chamber and change the length of the column.The average liquid film thickness and the liquid-phase mass transfer coefficient were measured,and a correlation for the Sherwood number,Reynolds number and Schmidt number was obtained for the modified wetted wall column.The equilibrium concentrations in chemical reactions were calculated with a minor absolute error for calculating the rate constant more accurately.A mathe-matical model for the CO2 absorption was established based on the diffusional mass transfer accompanied with parallel reversible reactions,and the partial differential equation was solved by Laplace transform.An analytical ex-pression for the concentration of carbon dioxide as a function of time and penetration depth in liquid film and the average interphase mass transfer rate was obtained.This model was also used to calculate the rate constant for a second-order reaction,which was in good agreement with reported data.展开更多
Absorption rate of CO2 into aqueous solution of N-methyldiethanolamine (MDEA) blended with diethanolamine (DEA) and piperazine (PZ) was studied and a kinetic model was established. It is shown that homogeneous activat...Absorption rate of CO2 into aqueous solution of N-methyldiethanolamine (MDEA) blended with diethanolamine (DEA) and piperazine (PZ) was studied and a kinetic model was established. It is shown that homogeneous activation mechanism could explain this absorption process. The absorption rate coefficients of carbon dioxide into MDEA aqueous solution blended with DEA, PZ or DEA+PZ were compared with each other. The results demonstrated that the different activation effect of DEA, PZ and DEA+PZ on the carbon dioxide absorption comes from the difference in CO2 combination rate, transport of PZ and DEA to MDEA and the regeneration rate of PZ and DEA.展开更多
Absorption of NOx into nitric acid solutions was studied in the presence of ozone by using a rotating packed bed(RPB) contactor.The influences of operating parameters,such as high gravity number,amount of ozone,gas ve...Absorption of NOx into nitric acid solutions was studied in the presence of ozone by using a rotating packed bed(RPB) contactor.The influences of operating parameters,such as high gravity number,amount of ozone,gas velocity,liquid spray density and inlet concentration of NOx,on the removal efficiency of NOx were investigated,among which the high gravity number and ozone amount are more important.Ozone was introduced to oxidize HNO2 to HNO3 to prevent the decomposition of HNO2 in the liquid phase.The high gravity number presents the effective external force for enhancing the mass transfer of ozone from gas phase to liquid phase.Under the experimental condition,the removal efficiency of NOx is higher than 90%and the concentration of nitric acid product exceeds 45%.展开更多
Photocatalytic reduction method using TiO2 suspension for removal as well as possibly recovery of silver （Ag（I）） in the presence of Cu（II） is examined. The photocatalytic reduction was performed by batch techniq...Photocatalytic reduction method using TiO2 suspension for removal as well as possibly recovery of silver （Ag（I）） in the presence of Cu（II） is examined. The photocatalytic reduction was performed by batch technique in a closed reactor equipped with UV lamp. The concentration of unreduced Ag（I） was analyzed by atomic absorption spectrophotometry method. The research results indicate that Ag（I） in the solution can be removed and recovered effectively as silver metal Ag（0） deposited on the surface of TiO2 for photocatalytic reduction. In addition, the presence of Cu（II） ion with increasing concentration leads to a proportional decline in Ag（I） photoreduction due to the prominent competition in the adsorption on the surface of TiO2. The effectiveness of Ag（I） ion photoreduction in the presence of Cu（II） ion is strongly influenced by solution pH and the highest photoreduction is obtained at pH 5 - 8, which is related with the speciation ofAg（I）, TiO2 surface as well as Cu（II） in the solution.展开更多
To understand the absorption mechanism of nitrogen dioxide into a sodium sulfide solution, a stirred tank reactor with a plane gas-liquid interface was used to measure the chemical absorption rate of diluted nitrogen ...To understand the absorption mechanism of nitrogen dioxide into a sodium sulfide solution, a stirred tank reactor with a plane gas-liquid interface was used to measure the chemical absorption rate of diluted nitrogen dioxide into sodium sulfide solution. The absorption rates under various experimental conditions were measured and the effects of experimental conditions on nitrogen dioxide absorption rate were discussed. The results show that, in the range of this study, nitrogen dioxide absorption rate increases with increasing sodium sulfide concentration, nitrogen dioxide inlet concentration, and flue gas flow rate, but decreases with increasing reaction temperature and oxygen content in flue gas.展开更多
基金Supported by China Petroleum&Chemical Corporation(105044)
文摘To get more accurate kinetic data of the absorption of CO2 into aqueous solution of N-methyldiethanolamine,a wetted wall column was modified to more uniformly distribute the liquid on the column surface and gas in the absorbing chamber and change the length of the column.The average liquid film thickness and the liquid-phase mass transfer coefficient were measured,and a correlation for the Sherwood number,Reynolds number and Schmidt number was obtained for the modified wetted wall column.The equilibrium concentrations in chemical reactions were calculated with a minor absolute error for calculating the rate constant more accurately.A mathe-matical model for the CO2 absorption was established based on the diffusional mass transfer accompanied with parallel reversible reactions,and the partial differential equation was solved by Laplace transform.An analytical ex-pression for the concentration of carbon dioxide as a function of time and penetration depth in liquid film and the average interphase mass transfer rate was obtained.This model was also used to calculate the rate constant for a second-order reaction,which was in good agreement with reported data.
文摘Absorption rate of CO2 into aqueous solution of N-methyldiethanolamine (MDEA) blended with diethanolamine (DEA) and piperazine (PZ) was studied and a kinetic model was established. It is shown that homogeneous activation mechanism could explain this absorption process. The absorption rate coefficients of carbon dioxide into MDEA aqueous solution blended with DEA, PZ or DEA+PZ were compared with each other. The results demonstrated that the different activation effect of DEA, PZ and DEA+PZ on the carbon dioxide absorption comes from the difference in CO2 combination rate, transport of PZ and DEA to MDEA and the regeneration rate of PZ and DEA.
基金Supported by the Fund of Science and Technology of Shanxi for Young Scholars(2007021012)Research Project of Shanxi Provincial Science and Technology Department(20090321113)
文摘Absorption of NOx into nitric acid solutions was studied in the presence of ozone by using a rotating packed bed(RPB) contactor.The influences of operating parameters,such as high gravity number,amount of ozone,gas velocity,liquid spray density and inlet concentration of NOx,on the removal efficiency of NOx were investigated,among which the high gravity number and ozone amount are more important.Ozone was introduced to oxidize HNO2 to HNO3 to prevent the decomposition of HNO2 in the liquid phase.The high gravity number presents the effective external force for enhancing the mass transfer of ozone from gas phase to liquid phase.Under the experimental condition,the removal efficiency of NOx is higher than 90%and the concentration of nitric acid product exceeds 45%.
文摘Photocatalytic reduction method using TiO2 suspension for removal as well as possibly recovery of silver （Ag（I）） in the presence of Cu（II） is examined. The photocatalytic reduction was performed by batch technique in a closed reactor equipped with UV lamp. The concentration of unreduced Ag（I） was analyzed by atomic absorption spectrophotometry method. The research results indicate that Ag（I） in the solution can be removed and recovered effectively as silver metal Ag（0） deposited on the surface of TiO2 for photocatalytic reduction. In addition, the presence of Cu（II） ion with increasing concentration leads to a proportional decline in Ag（I） photoreduction due to the prominent competition in the adsorption on the surface of TiO2. The effectiveness of Ag（I） ion photoreduction in the presence of Cu（II） ion is strongly influenced by solution pH and the highest photoreduction is obtained at pH 5 - 8, which is related with the speciation ofAg（I）, TiO2 surface as well as Cu（II） in the solution.
基金supported by the Key Project of the National Key Technologies Supporting Program of China during the 11th Five-Year Plan Period (No. 2006BAA01B04)the Program for New Excellent Talents in University (No. NCET-06-0513), China
文摘To understand the absorption mechanism of nitrogen dioxide into a sodium sulfide solution, a stirred tank reactor with a plane gas-liquid interface was used to measure the chemical absorption rate of diluted nitrogen dioxide into sodium sulfide solution. The absorption rates under various experimental conditions were measured and the effects of experimental conditions on nitrogen dioxide absorption rate were discussed. The results show that, in the range of this study, nitrogen dioxide absorption rate increases with increasing sodium sulfide concentration, nitrogen dioxide inlet concentration, and flue gas flow rate, but decreases with increasing reaction temperature and oxygen content in flue gas.
