The degradation of atrazine (ATZ),sulfamethoxazole (SMX) and metoprolol (MET) in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter (ID).Results sh...The degradation of atrazine (ATZ),sulfamethoxazole (SMX) and metoprolol (MET) in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter (ID).Results showed that the micropollutants were degraded efficiently in the flow-through VUV/UV/H2O2reactors following the pseudo first-order kinetics (R2>0.92).However,the steady-state assumption (SSA) kinetic model being vital in batch reactors was found invalid in flow-through reactors where fluid mixing was less sufficient.With the increase of H2O2dosage,the ATZ removal efficiency remained almost constant while the SMX and MET removal was enhanced to different extents,which could be explained by the different reactivities of the pollutants towards HO·.A larger reactor ID resulted in lower degradation rate constants for all the three pollutants on account of the lower average fluence rate,but the change in energy efficiency was much more complicated.In reality,the electrical energy per order (EEO) of the investigated VUV/UV/H2O2treatments ranged between 0.14–0.20,0.07–0.14 and 0.09–0.26 k Wh/m3/order for ATZ,SMX and MET,respectively,with the lowest EEOfor each pollutant obtained under varied H2O2dosages and reactor IDs.This study has demonstrated the efficiency of VUV/UV/H2O2process for micropollutant removal and the inadequacy of the SSA model in flow-through reactors,and elaborated the influential mechanisms of H2O2dosage and reactor ID on the reactor performances.展开更多
Manganese ion(Mn^(2+))was generated from metallurgical,steel making and chemical industries.It could affect microbial activity and community structure after entering sewage treatment plant.The effect of Mn^(2+)on the ...Manganese ion(Mn^(2+))was generated from metallurgical,steel making and chemical industries.It could affect microbial activity and community structure after entering sewage treatment plant.The effect of Mn^(2+)on the pollutant removal,metal distribution patterns and composition of microbial communities were investigated in a an anaerobic/anoxic/oxic(A^(2)O)process.The results showed that when Mn^(2+)concentration was 5 mg/L,the efficiencies for the removal of chemical oxygen demand(COD),total nitrogen(TN)and total phosphorus(TP)attained remarkable levels of 96%,93%,and 99%,respectively.In the sludge,the distribution pattern of Mn^(2+)concentration was tightly bound extracellular polymeric substances(TB-EPS)>supernatant>loosely bound EPS(LB-EPS)>soluble microbial products(SMP).Mn^(2+)was found to enrich and accumulate in the microorganism cells.In addition,Mn^(2+)was mainly found in residual fractions and reducible fractions of pellet that manganese was present.The pellet was discovered to contain a substantial quantity of manganese,which was present in various oxidation states,including Mn^(4+),Mn^(3+)and Mn^(2+).The escalating levels of Mn^(2+)led to a reduction in the richness and diversity of microbial communities inhabiting various regions of the A^(2)O reactor.Nonetheless,the uniformity experienced only subtle alterations.Proteobacteria and Bacteroidetes emerged as the leading phyla within the microbial ecosystem,experiencing a steady rise in their respective proportions.The dominant bacterial groups,Azospira and Dechromonas,experienced an incremental increase in their relative prevalence,which played a constructive role in the process of pollutant removal.展开更多
The CuO/γ-Al2O3/cordierite catalyst, after being sulfated by sulfur dioxide (SO2) at 673 K, exhibits high activities for selective catalytic reduction (SCR) of nitrogen oxide (NO) with ammonia (NH3) at 573-723 K. The...The CuO/γ-Al2O3/cordierite catalyst, after being sulfated by sulfur dioxide (SO2) at 673 K, exhibits high activities for selective catalytic reduction (SCR) of nitrogen oxide (NO) with ammonia (NH3) at 573-723 K. The intrinsic kinetics of SCR of NO with NH3 over CuO/γ-Al2O3/cordierite catalyst has been measured in a fixed-bed reactor in the absence of internal and external diffusions. The experimental results show that the reaction rate can be quantified by a first-order expression with activation energy Eá of 94.01 kJ·mol-1 and the corresponding p re-exponential factor A′ of 3.39×108 cm3·g-1·s-1 when NH3 is excessive. However, when NH3 is not enough, an E ley-Rideal kinetic model based on experimental data is derived with Ea of 105.79 kJ·mol-1, the corresponding A of 2 .94×109 cm3·g-1·s-1, heat of adsorption-Hads of 87.90 kJ·mol-1 and the corresponding Aads of 9.24 cm3·mol-1. The intrinsic kinetic model obtained was incorporated in a 3D mathematical model of monolithic reactor, and the agreement of the prediction with experimental data indicates that the present kinetic model is adequate for the reac-tor design and engineering scale-up.展开更多
An industrial scale propylene production via oxidative dehydrogenation of propane （ODHP） in multi-tubular re- actors was modeled. Multi-tubular fixed-bed reactor used for ODHP process, employing 10000 of small diame...An industrial scale propylene production via oxidative dehydrogenation of propane （ODHP） in multi-tubular re- actors was modeled. Multi-tubular fixed-bed reactor used for ODHP process, employing 10000 of small diameter tubes immersed in a shell through a proper coolant flows. Herein, a theory-based pseudo-homogeneous model to describe the operation of a fixed bed reactor for the ODHP to correspondence olefln over V2O5/γ-Al203 catalyst was presented. Steady state one dimensional model has been developed to identify the operation parameters and to describe the propane and oxygen conversions, gas process and coolant temperatures, as well as other pa- rameters affecting the reactor performance such as pressure. Furthermore, the applied model showed that a double-bed multitubular reactor with intermediate air injection scheme was superior to a single-bed design due to the increasing of propylene selectivity while operating under lower oxygen partial pressures resulting in propane conversion of about 37.3%. The optimized length of the reactor needed to reach 100% conversion of the oxygen was theoretically determined. For the single-bed reactor the optimized length of 11.96 m including 0.5 m of inert section at the entrance region and for the double-bed reactor design the optimized lengths of 5.72 m for the first and 7.32 m for the second reactor were calculated. Ultimately, the use of a distributed oxygen feed with limited number of injection points indicated a significant improvement on the reactor performance in terms of propane conversion and propylene selectivity. Besides, this concept could overcome the reactor run- away temperature problem and enabled operations at the wider range of conditions to obtain enhanced propyl- ene production in an industrial scale reactor.展开更多
To improve the working and living environment of submarine crews, an integrated system of CO2 removal and O2 regeneration was designed to work under experimental conditions for 50 people in a submarine cabin during pr...To improve the working and living environment of submarine crews, an integrated system of CO2 removal and O2 regeneration was designed to work under experimental conditions for 50 people in a submarine cabin during prolonged voyages. The integrated system comprises a solid amine water desorption （SAWD） unit for CO2 collection and concentration, a Sabatier reactor for CO2 reduction and a solid polymer electrolyte （SPE） unit for O2 regeneration by electrolysis. The performances of the SAWD-Sabatier-SPE integrated system were investigated. The experimental results from the SAWD unit showed that the average CO2 concentration in the CO2 storage tank was more than 96% and the outlet CO2 concentration was nearly zero in the first 45 min, and less than 1/10 of inlet CO2 after 60 min when input CO2 was 0.5% （1000 L）. About 950 L of CO2 was recovered with a recovery rate of 92%-97%. The output CO2 concentration was less than 0.2%, which showed that the adsorption-desorption performance of this unit was excellent. In the CO2 reduction unit we investigated mainly the start-up and reaction performance of the Sabatier reactor. The start-up time of the Sabatier reactor was 6, 8 and 10 rain when the start-up temperature was 187.3, 179.5 and 168 ℃, respectively. The product water was colorless, transparent, and had a pH of 6.9-7.5, and an electrical conductivity of 80μs/cm. The sum of the concentration of metal ions （Ru^3＋, Al^3＋, Pb^2＋） was 0.028% and that of nonmetal ions （Cl^-, SO4^2-） was 0.05%. In the O2 regeneration unit, the O2 generation rate was 0.48 m^3/d and the quantity was 2400 L, sufficient to meet the submariners＇ basic oxygen demands. These results may be useful as a basis for establishing CO2-1evel limits and O2 regeneration systems in submarines or similar enclosed compartments during prolonged voyages.展开更多
基金supported by the National Natural Science Foundation of China(No.51908536)the Ministry of Science and Technology of China(No.2018YFE0204103)。
文摘The degradation of atrazine (ATZ),sulfamethoxazole (SMX) and metoprolol (MET) in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter (ID).Results showed that the micropollutants were degraded efficiently in the flow-through VUV/UV/H2O2reactors following the pseudo first-order kinetics (R2>0.92).However,the steady-state assumption (SSA) kinetic model being vital in batch reactors was found invalid in flow-through reactors where fluid mixing was less sufficient.With the increase of H2O2dosage,the ATZ removal efficiency remained almost constant while the SMX and MET removal was enhanced to different extents,which could be explained by the different reactivities of the pollutants towards HO·.A larger reactor ID resulted in lower degradation rate constants for all the three pollutants on account of the lower average fluence rate,but the change in energy efficiency was much more complicated.In reality,the electrical energy per order (EEO) of the investigated VUV/UV/H2O2treatments ranged between 0.14–0.20,0.07–0.14 and 0.09–0.26 k Wh/m3/order for ATZ,SMX and MET,respectively,with the lowest EEOfor each pollutant obtained under varied H2O2dosages and reactor IDs.This study has demonstrated the efficiency of VUV/UV/H2O2process for micropollutant removal and the inadequacy of the SSA model in flow-through reactors,and elaborated the influential mechanisms of H2O2dosage and reactor ID on the reactor performances.
基金supported by Jilin Provincial Department of Education Science and Technology Project(No.JJKH20230152KJ)the Doctoral Research Initiation Fund(No.BSJXM-2022215).
文摘Manganese ion(Mn^(2+))was generated from metallurgical,steel making and chemical industries.It could affect microbial activity and community structure after entering sewage treatment plant.The effect of Mn^(2+)on the pollutant removal,metal distribution patterns and composition of microbial communities were investigated in a an anaerobic/anoxic/oxic(A^(2)O)process.The results showed that when Mn^(2+)concentration was 5 mg/L,the efficiencies for the removal of chemical oxygen demand(COD),total nitrogen(TN)and total phosphorus(TP)attained remarkable levels of 96%,93%,and 99%,respectively.In the sludge,the distribution pattern of Mn^(2+)concentration was tightly bound extracellular polymeric substances(TB-EPS)>supernatant>loosely bound EPS(LB-EPS)>soluble microbial products(SMP).Mn^(2+)was found to enrich and accumulate in the microorganism cells.In addition,Mn^(2+)was mainly found in residual fractions and reducible fractions of pellet that manganese was present.The pellet was discovered to contain a substantial quantity of manganese,which was present in various oxidation states,including Mn^(4+),Mn^(3+)and Mn^(2+).The escalating levels of Mn^(2+)led to a reduction in the richness and diversity of microbial communities inhabiting various regions of the A^(2)O reactor.Nonetheless,the uniformity experienced only subtle alterations.Proteobacteria and Bacteroidetes emerged as the leading phyla within the microbial ecosystem,experiencing a steady rise in their respective proportions.The dominant bacterial groups,Azospira and Dechromonas,experienced an incremental increase in their relative prevalence,which played a constructive role in the process of pollutant removal.
基金Supported by the National Natural Science Foundation of China （20821004 20736001 21076008） the Research Fund for the Doctoral Program of Higher Education of China （2090010110002）
文摘The CuO/γ-Al2O3/cordierite catalyst, after being sulfated by sulfur dioxide (SO2) at 673 K, exhibits high activities for selective catalytic reduction (SCR) of nitrogen oxide (NO) with ammonia (NH3) at 573-723 K. The intrinsic kinetics of SCR of NO with NH3 over CuO/γ-Al2O3/cordierite catalyst has been measured in a fixed-bed reactor in the absence of internal and external diffusions. The experimental results show that the reaction rate can be quantified by a first-order expression with activation energy Eá of 94.01 kJ·mol-1 and the corresponding p re-exponential factor A′ of 3.39×108 cm3·g-1·s-1 when NH3 is excessive. However, when NH3 is not enough, an E ley-Rideal kinetic model based on experimental data is derived with Ea of 105.79 kJ·mol-1, the corresponding A of 2 .94×109 cm3·g-1·s-1, heat of adsorption-Hads of 87.90 kJ·mol-1 and the corresponding Aads of 9.24 cm3·mol-1. The intrinsic kinetic model obtained was incorporated in a 3D mathematical model of monolithic reactor, and the agreement of the prediction with experimental data indicates that the present kinetic model is adequate for the reac-tor design and engineering scale-up.
文摘An industrial scale propylene production via oxidative dehydrogenation of propane （ODHP） in multi-tubular re- actors was modeled. Multi-tubular fixed-bed reactor used for ODHP process, employing 10000 of small diameter tubes immersed in a shell through a proper coolant flows. Herein, a theory-based pseudo-homogeneous model to describe the operation of a fixed bed reactor for the ODHP to correspondence olefln over V2O5/γ-Al203 catalyst was presented. Steady state one dimensional model has been developed to identify the operation parameters and to describe the propane and oxygen conversions, gas process and coolant temperatures, as well as other pa- rameters affecting the reactor performance such as pressure. Furthermore, the applied model showed that a double-bed multitubular reactor with intermediate air injection scheme was superior to a single-bed design due to the increasing of propylene selectivity while operating under lower oxygen partial pressures resulting in propane conversion of about 37.3%. The optimized length of the reactor needed to reach 100% conversion of the oxygen was theoretically determined. For the single-bed reactor the optimized length of 11.96 m including 0.5 m of inert section at the entrance region and for the double-bed reactor design the optimized lengths of 5.72 m for the first and 7.32 m for the second reactor were calculated. Ultimately, the use of a distributed oxygen feed with limited number of injection points indicated a significant improvement on the reactor performance in terms of propane conversion and propylene selectivity. Besides, this concept could overcome the reactor run- away temperature problem and enabled operations at the wider range of conditions to obtain enhanced propyl- ene production in an industrial scale reactor.
基金supported by the National Natural Science Foundation of China (No. 50908062)the State Key Lab of Urban Water Resource and Environment (No. HIT-QAK200808)the Heilongjiang Natural Science Foundation (No. E2007-04), China
文摘To improve the working and living environment of submarine crews, an integrated system of CO2 removal and O2 regeneration was designed to work under experimental conditions for 50 people in a submarine cabin during prolonged voyages. The integrated system comprises a solid amine water desorption （SAWD） unit for CO2 collection and concentration, a Sabatier reactor for CO2 reduction and a solid polymer electrolyte （SPE） unit for O2 regeneration by electrolysis. The performances of the SAWD-Sabatier-SPE integrated system were investigated. The experimental results from the SAWD unit showed that the average CO2 concentration in the CO2 storage tank was more than 96% and the outlet CO2 concentration was nearly zero in the first 45 min, and less than 1/10 of inlet CO2 after 60 min when input CO2 was 0.5% （1000 L）. About 950 L of CO2 was recovered with a recovery rate of 92%-97%. The output CO2 concentration was less than 0.2%, which showed that the adsorption-desorption performance of this unit was excellent. In the CO2 reduction unit we investigated mainly the start-up and reaction performance of the Sabatier reactor. The start-up time of the Sabatier reactor was 6, 8 and 10 rain when the start-up temperature was 187.3, 179.5 and 168 ℃, respectively. The product water was colorless, transparent, and had a pH of 6.9-7.5, and an electrical conductivity of 80μs/cm. The sum of the concentration of metal ions （Ru^3＋, Al^3＋, Pb^2＋） was 0.028% and that of nonmetal ions （Cl^-, SO4^2-） was 0.05%. In the O2 regeneration unit, the O2 generation rate was 0.48 m^3/d and the quantity was 2400 L, sufficient to meet the submariners＇ basic oxygen demands. These results may be useful as a basis for establishing CO2-1evel limits and O2 regeneration systems in submarines or similar enclosed compartments during prolonged voyages.
