Electrocatalytic carbon dioxide reduction is a promising technology for addressing global energy and environmental crises. However, its practical application faces two critical challenges: the complex and energy-inten...Electrocatalytic carbon dioxide reduction is a promising technology for addressing global energy and environmental crises. However, its practical application faces two critical challenges: the complex and energy-intensive process of separat-ing mixed reduction products and the economic viability of the carbon sources (reactants) used. To tackle these challenges simultaneously, solid-state electrolyte (SSE) reactors are emerging as a promising solution. In this review, we focus on the feasibility of applying SSE for tandem electrochemical CO_(2) capture and conversion. The configurations and fundamental principles of SSE reactors are first discussed, followed by an introduction to its applications in these two specific areas, along with case studies on the implementation of tandem electrolysis. In comparison to conventional H-type cell, flow cell and membrane electrode assembly cell reactors, SSE reactors incorporate gas diffusion electrodes and utilize a solid electro-lyte layer positioned between an anion exchange membrane (AEM) and a cation exchange membrane (CEM). A key inno-vation of this design is the sandwiched SSE layer, which enhances efficient ion transport and facilitates continuous product extraction through a stream of deionized water or humidified nitrogen, effectively separating ion conduction from product collection. During electrolysis, driven by an electric field and concentration gradient, electrochemically generated ions (e.g., HCOO- and CH3COO-) migrate through the AEM into the SSE layer, while protons produced from water oxidation at the anode traverse the CEM into the central chamber to maintain charge balance. Targeted products like HCOOH can form in the middle layer through ionic recombination and are efficiently carried away by the flowing medium through the porous SSE layer, in the absence of electrolyte salt impurities. As CO_(2)RR can generate a series of liquid products, advancements in catalyst discovery over the past several years have facilitated the industrial application of SSE for more efficient chemicals production. Also noteworthy, the cathode reduction reaction can readily consume protons from water, creating a highly al-kaline local environment. SSE reactors are thereby employed to capture acidic CO_(2), forming CO_(3)^(2-) from various gas sources including flue gases. Driven by the electric field, the formed CO_(3)^(2-) can traverse through the AEM and react with protons originating from the anode, thereby regenerating CO_(2). This CO_(2) can then be collected and utilized as a low-cost feedstock for downstream CO_(2) electrolysis. Based on this principle, several cell configurations have been proposed to enhance CO_(2) capture from diverse gas sources. Through the collaboration of two SSE units, tandem electrochemical CO_(2) capture and con-version has been successfully implemented. Finally, we offer insights into the future development of SSE reactors for prac-tical applications aimed at achieving carbon neutrality. We recommend that greater attention be focused on specific aspects, including the fundamental physicochemical properties of the SSE layer, the electrochemical engineering perspective related to ion and species fluxes and selectivity, and the systematic pairing of consecutive CO_(2) capture and conversion units. These efforts aim to further enhance the practical application of SSE reactors within the broader electrochemistry community.展开更多
Batch to batch temperature control of a semi-batch chemical reactor with heating/cooling system was discussed in this study. Without extensive modeling investigations, a two-dimensional(2D) general predictive iterativ...Batch to batch temperature control of a semi-batch chemical reactor with heating/cooling system was discussed in this study. Without extensive modeling investigations, a two-dimensional(2D) general predictive iterative learning control(2D-MGPILC) strategy based on the multi-model with time-varying weights was introduced for optimizing the tracking performance of desired temperature profile. This strategy was modeled based on an iterative learning control(ILC) algorithm for a 2D system and designed in the generalized predictive control(GPC) framework. Firstly, a multi-model structure with time-varying weights was developed to describe the complex operation of a general semi-batch reactor. Secondly, the 2 D-MGPILC algorithm was proposed to optimize simultaneously the dynamic performance along the time and batch axes. Finally, simulation for the controller design of a semi-batch reactor with multiple reactions was involved to demonstrate that the satisfactory performance could be achieved despite of the repetitive or non-repetitive disturbances.展开更多
A solution of 0.1 mol/L to 1.0 mol/L H2SO4 can dissolve alkali metals and alkaline earth metals which weaken an active site of SCR catalyst. The waste catalyst washed with 0.5 mol/L H2SO4 regained the best catalytic a...A solution of 0.1 mol/L to 1.0 mol/L H2SO4 can dissolve alkali metals and alkaline earth metals which weaken an active site of SCR catalyst. The waste catalyst washed with 0.5 mol/L H2SO4 regained the best catalytic activity. When a concentration of the sulfuric acid is less than 0.5 mol/L, sufficient cleaning effects cannot be obtained. In contrast, when the concentration is greater than 1.0 tool/L, the active components, vanadium and tungsten are undesirably eluted. The total BET surface of the catalyst regenerated by air lift loop reactor showed almost the same as that of fresh catalyst due to the removal of insoluble compounds which may be penetrated into pores of catalyst. The addition of a solution of 0.075 mol/L ammonium vanadate （NHnVO3） and 0.075 mol/L ammonium paratungstate （5（NH4）20· 12WO3-5H20） to 0.1 mol/L H2SO4 significantly increases the activity of the waste catalyst.展开更多
Optical grade diamond, in particular, high-end products, are mainly used for aerospace and defense purposes. How to manufacture them with higher quality and lower cost was critical technology. Systematic research on t...Optical grade diamond, in particular, high-end products, are mainly used for aerospace and defense purposes. How to manufacture them with higher quality and lower cost was critical technology. Systematic research on the performance of Self-designed plasma reactor with higher power for synthesizing diamond film was carried out. Microwave input power can reach up to 10 kW, the plasma reactor has good adaptability for the deviation of microwave frequency f at 2.45 GHz ± 20 MHz. The secondary plasma could be eliminated by adjusting the working gas pressure and the cylinder adjustment structure,it is helpful to improve the deposition rate with less energy loss. The concentrated and steady plasma could be obtained device with higher gas pressure and relative lower microwave input power. Gas supply modes and inlet gas flow rate were optimized, which would be beneficial to synthesize the film with good quality.展开更多
In this study, a lab-scale upflow anaerobic sludge blanket(UASB) reactor was applied to studying the high-rate nitrogen removal of granule-based anammox process. The nitrogen removal rate(NRR) finally improved to 15.7...In this study, a lab-scale upflow anaerobic sludge blanket(UASB) reactor was applied to studying the high-rate nitrogen removal of granule-based anammox process. The nitrogen removal rate(NRR) finally improved to 15.77 kg/m3/d by shortening hydraulic retention time(HRT) to 1.06 h. Well-shaped red anammox granules were extensively enriched inside the reactor. The results of nitrogen removal kinetics indicated that the present bioreactor has great nitrogen removal potential, because the maximum rate of substrate utilization(Umax) predicted by Stover-Kincannon model is suggested as 55.68 kg/(m3·d). Analysis of the microbial community showed that the anammox genus Candidatus Kuenenia dominated the bacterial communities. The relative abundance of Candidatus Kuenenia rose from 12.29% to 36.95% after progressively shorter HRT and higher influent substrate concentrations, illustrating the stability of nitrogen removal performance and biomass enrichment offered by the UASB in carrying out high-rate anammox process.展开更多
Combined technology of SDS-CuO/TiO2 photocatalysis and sequencing batch reactor （SBR） were applied to treating dyestuff wastewater. Photocatalysis was carried out in a spiral up-flow type reactor as pre-treatment. S...Combined technology of SDS-CuO/TiO2 photocatalysis and sequencing batch reactor （SBR） were applied to treating dyestuff wastewater. Photocatalysis was carried out in a spiral up-flow type reactor as pre-treatment. SDS-CuO/TiO2 photocatalyst was prepared by modification of nano-TiO2 using CuO and sodium dodecyl sulfate （SDS）. Results show that the SDS-CuO/TiO2 photocatalyst contains two kinds of crystals, including TiO2 and CuO. The band gap of this photocatalyst is 1.56 eV, indicating that it can be excited by visible light （2〈794.87 nm）. And characterization also shows that there are alkyl groups on its surface. It takes 40 rain to improve the biodegradability of dyestuff wastewater. Five-day biochemical oxygen demand （BODs） and dehydrogenase activity （DHA） of wastewater reach the maximum value when dissolved oxygen is higher than 2.97 mg/L. SBR reactor was used to treat this biodegradability improved wastewater. Chemical oxygen demand （COD） and colority decline to 72 mg/L and 20 times, respectively, when the sludge loading is 0.179 kg（COD）/[kg（MLSS）＇d], dissolved oxygen is 4.09 mg/L and aeration time is 10 h.展开更多
High salinity industrial wastewater is difficult to treat using biological treatment system because of the high concentrations of salt.The potential of a sequencing batch biofilm reactor(SBBR)process in treating synth...High salinity industrial wastewater is difficult to treat using biological treatment system because of the high concentrations of salt.The potential of a sequencing batch biofilm reactor(SBBR)process in treating synthetic high salinity wastewater was evaluated at laboratory scale during a 110-day operation.The reactor was operated in a 12 h cycle,and each cycle consisted of 0.25 h influent addition,8 h aeration,3 h anoxic reaction,0.5 h sedimentation and 0.25 h effluent withdrawal.Gradual increase in salinity gradient was applied during the acclimatization period.The acclimated SBBR system was demonstrated to be an effective process to remove organic compounds and ammonia nitrogen under high salinity conditions with chemical oxygen demand(COD)and ammonia nitrogen(NH3-N)removal efficiencies of 88% and 80%,respectively.The microscopic examination indicated that rather than rotifers or vorticella,the zoogloea,filamentous fungus mingled with a small quantity of swimming infusorians were dominant bacteria in SBBR system.The removal efficiencies close to 80% in COD and 75% in NH3-N were achieved at an organic loading rate(OLR)of 0.96 kg COD/(m3·d),pH of 7.0,salinity of 14 g/L and NH3-N of 30 mg/L.展开更多
The mixing time of impact zone in liquid-continuous impinging streams reactor(LISR) is theoretically calculated by empirical model and modern micromixing model of the fluid mixing process, and the variation laws of ma...The mixing time of impact zone in liquid-continuous impinging streams reactor(LISR) is theoretically calculated by empirical model and modern micromixing model of the fluid mixing process, and the variation laws of macromixing time and micromixing time are quantitatively discussed. The results show that under a continuous and stable operating condition, as the paddle speed increases, the macromixing time and micromixing time calculated by the two models both decrease, even in a linkage equilibrium state. Simultaneously, as the paddle speed increases, the results figured by the two models tend to be consistent. It indicates that two models both are more suitable for calculation of mixing time in high paddle speed. Compared with the existing experimental results of this type of reactor, the mixing time computed in the speed of 1500 r/min is closer to it. These conclusions can provide an important reference for systematically studying the strengthening mechanism of LISR under continuous mixing conditions.展开更多
The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor （SBR）, and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances （EPS） of sludge samples were e...The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor （SBR）, and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances （EPS） of sludge samples were extracted and analyzed during the granulation and storage process. The results show that the contents of protein and EPS increase along with the granulation process, while polysaccharides remain almost unchanged. The content of protein in EPS is almost two-fold larger than that of polysaccharides in granular sludge cultivated with municipal wastewater. Moreover, some of the granules disintegrate during storage, corresponding to the decrease of protein contents in EPS. Three peaks are identified in three-dimensional excitation emission matrix （EEM） fluorescence spectra of the EPS in the aerobic granules. Two peaks （A and B） are attributed to the protein-like fluorophores, and the third （peak C） is related to visible fulvic-like substances. Peak A gradually disappears during storage, while a new peak related to ultraviolet fulvic acid （peak D） is formed. The formation and the stability of aerobic granules are closely dependent on the quantity and composition of EPS proteins. Peak C has no obvious changes during granulation, while the fulvic-like substances present an increase in fluorescence intensities during storage, accompanied with an increase in structural complexity. The fulvie-like substances are also associated with the disintegration of the aerobic granules.展开更多
The start-up of external circulationadded internal circulation(IC) reactor was finished in 26 d, 32 d fewer than that of IC reactor. To evaluate the influence of the added external circulation on the development of gr...The start-up of external circulationadded internal circulation(IC) reactor was finished in 26 d, 32 d fewer than that of IC reactor. To evaluate the influence of the added external circulation on the development of granular sludge, the characteristics of the granular sludge taken from the two tested laboratory-scale reactors during start-up were studied. The results show that the added external circulation can enhance biomass granulation, accelerate granule development and improve sludge characteristics. At the end of start-up, the granular size of sludge in external circulation-added IC reactor greatly increases with a size distribution much better than that of sludge in IC reactor. The granular sludge originated from external circulationadded IC reactor contains more extracellular polymers and has a greater settling velocity than that from IC reactor. Methanogenic activity of the granular sludge from the external circulationadded IC reactor started 26 d ago reaches 358.23mL·g -1 ·d -1 , 1.66 and 1.20 times as great as that of the sludge from the IC reactor started 26 d and 58 d ago respectively.展开更多
Metal organic chemical vapor deposition(MOCVD) is a key equipment in the manufacturing of semiconductor optoelectronic devices and microwave devices in industry. Heating system is a vital part of MOCVD. Specific heati...Metal organic chemical vapor deposition(MOCVD) is a key equipment in the manufacturing of semiconductor optoelectronic devices and microwave devices in industry. Heating system is a vital part of MOCVD. Specific heating device and thermal control technology are needed for each new reactor design. By using resistance-wire heating MOCVD reaction chamber model, thermal analysis and structure optimization of the reactor were developed from the vertical position and the distance between coils of the resistance-wire heater. It is indicated that, within a certain range, the average temperature of the graphite susceptor varies linearly with the vertical distance of heater to susceptor, and with the changed distances between the coils; furthermore, single resistance-wire heater should be placed loosely in the internal and tightly in the external. The modulate accuracy of the temperature field approximately equals the change of the average temperature corresponding to the change of the coil position.展开更多
The Daubechies second order wavelet was applied to decompose pressure fluctuation signals with the gas flux varying from 0.18 to 0.90 m3/h and the solid mass fraction from 0 to 20% and scales 1?9 detail signals and th...The Daubechies second order wavelet was applied to decompose pressure fluctuation signals with the gas flux varying from 0.18 to 0.90 m3/h and the solid mass fraction from 0 to 20% and scales 1?9 detail signals and the 9th scale approximation signals. The pressure signals were studied by multi-scale and R/S analysis method. Hurst analysis method was applied to analyze multi-fractal characteristics of different scale signals. The results show that the characteristics of mono-fractal under scale 1 and scale 2, and bi-fractal under scale 3?9 are effective in deducing the hydrodynamics in slurry bubbling flow system. The measured pressure signals are decomposed to micro-scale signals, meso-scale signals and macro-scale signals. Micro-scale and macro-scale signals are of mono-fractal characteristics, and meso-scale signals are of bi-fractal characteristics. By analyzing energy distribution of different scale signals,it is shown that pressure fluctuations mainly reflects meso-scale interaction between the particles and the bubble.展开更多
PVA/ Chitosan (CS) composite membrane was studied in this paper, which could be used for enzyme processing of fat and oils. The parameters such as concentration of lipase, pH, and cross-linking agent as well as metal ...PVA/ Chitosan (CS) composite membrane was studied in this paper, which could be used for enzyme processing of fat and oils. The parameters such as concentration of lipase, pH, and cross-linking agent as well as metal ions, which influence the immobilization of lipase in membrane, were optimized. The immobilized lipase was 0.66 u/cm2 and the recovery of immobilized lipase activity was 24%. The membrane reactor could be used to synthesize monoglyceride (MG) with many batches.展开更多
基金This work was supported by the National Key R&D Program of China(2022YFB4102000 and 2022YFA1505100)the NSFC(22472038)the Shanghai Science and Technology Innovation Action Plan(22dz1205500).
文摘Electrocatalytic carbon dioxide reduction is a promising technology for addressing global energy and environmental crises. However, its practical application faces two critical challenges: the complex and energy-intensive process of separat-ing mixed reduction products and the economic viability of the carbon sources (reactants) used. To tackle these challenges simultaneously, solid-state electrolyte (SSE) reactors are emerging as a promising solution. In this review, we focus on the feasibility of applying SSE for tandem electrochemical CO_(2) capture and conversion. The configurations and fundamental principles of SSE reactors are first discussed, followed by an introduction to its applications in these two specific areas, along with case studies on the implementation of tandem electrolysis. In comparison to conventional H-type cell, flow cell and membrane electrode assembly cell reactors, SSE reactors incorporate gas diffusion electrodes and utilize a solid electro-lyte layer positioned between an anion exchange membrane (AEM) and a cation exchange membrane (CEM). A key inno-vation of this design is the sandwiched SSE layer, which enhances efficient ion transport and facilitates continuous product extraction through a stream of deionized water or humidified nitrogen, effectively separating ion conduction from product collection. During electrolysis, driven by an electric field and concentration gradient, electrochemically generated ions (e.g., HCOO- and CH3COO-) migrate through the AEM into the SSE layer, while protons produced from water oxidation at the anode traverse the CEM into the central chamber to maintain charge balance. Targeted products like HCOOH can form in the middle layer through ionic recombination and are efficiently carried away by the flowing medium through the porous SSE layer, in the absence of electrolyte salt impurities. As CO_(2)RR can generate a series of liquid products, advancements in catalyst discovery over the past several years have facilitated the industrial application of SSE for more efficient chemicals production. Also noteworthy, the cathode reduction reaction can readily consume protons from water, creating a highly al-kaline local environment. SSE reactors are thereby employed to capture acidic CO_(2), forming CO_(3)^(2-) from various gas sources including flue gases. Driven by the electric field, the formed CO_(3)^(2-) can traverse through the AEM and react with protons originating from the anode, thereby regenerating CO_(2). This CO_(2) can then be collected and utilized as a low-cost feedstock for downstream CO_(2) electrolysis. Based on this principle, several cell configurations have been proposed to enhance CO_(2) capture from diverse gas sources. Through the collaboration of two SSE units, tandem electrochemical CO_(2) capture and con-version has been successfully implemented. Finally, we offer insights into the future development of SSE reactors for prac-tical applications aimed at achieving carbon neutrality. We recommend that greater attention be focused on specific aspects, including the fundamental physicochemical properties of the SSE layer, the electrochemical engineering perspective related to ion and species fluxes and selectivity, and the systematic pairing of consecutive CO_(2) capture and conversion units. These efforts aim to further enhance the practical application of SSE reactors within the broader electrochemistry community.
基金Projects(61673205,21727818,61503180)supported by the National Natural Science Foundation of ChinaProject(2017YFB0307304)supported by National Key R&D Program of ChinaProject(BK20141461)supported by the Natural Science Foundation of Jiangsu Province,China
文摘Batch to batch temperature control of a semi-batch chemical reactor with heating/cooling system was discussed in this study. Without extensive modeling investigations, a two-dimensional(2D) general predictive iterative learning control(2D-MGPILC) strategy based on the multi-model with time-varying weights was introduced for optimizing the tracking performance of desired temperature profile. This strategy was modeled based on an iterative learning control(ILC) algorithm for a 2D system and designed in the generalized predictive control(GPC) framework. Firstly, a multi-model structure with time-varying weights was developed to describe the complex operation of a general semi-batch reactor. Secondly, the 2 D-MGPILC algorithm was proposed to optimize simultaneously the dynamic performance along the time and batch axes. Finally, simulation for the controller design of a semi-batch reactor with multiple reactions was involved to demonstrate that the satisfactory performance could be achieved despite of the repetitive or non-repetitive disturbances.
基金Project(2009T100100602) supported by the Korea Institute of Energy Technology Evaluation and Planning,Korea
文摘A solution of 0.1 mol/L to 1.0 mol/L H2SO4 can dissolve alkali metals and alkaline earth metals which weaken an active site of SCR catalyst. The waste catalyst washed with 0.5 mol/L H2SO4 regained the best catalytic activity. When a concentration of the sulfuric acid is less than 0.5 mol/L, sufficient cleaning effects cannot be obtained. In contrast, when the concentration is greater than 1.0 tool/L, the active components, vanadium and tungsten are undesirably eluted. The total BET surface of the catalyst regenerated by air lift loop reactor showed almost the same as that of fresh catalyst due to the removal of insoluble compounds which may be penetrated into pores of catalyst. The addition of a solution of 0.075 mol/L ammonium vanadate （NHnVO3） and 0.075 mol/L ammonium paratungstate （5（NH4）20· 12WO3-5H20） to 0.1 mol/L H2SO4 significantly increases the activity of the waste catalyst.
基金funded by the Inner Mongolia Natural Science Foundation under Grant No. 2017MS0539
文摘Optical grade diamond, in particular, high-end products, are mainly used for aerospace and defense purposes. How to manufacture them with higher quality and lower cost was critical technology. Systematic research on the performance of Self-designed plasma reactor with higher power for synthesizing diamond film was carried out. Microwave input power can reach up to 10 kW, the plasma reactor has good adaptability for the deviation of microwave frequency f at 2.45 GHz ± 20 MHz. The secondary plasma could be eliminated by adjusting the working gas pressure and the cylinder adjustment structure,it is helpful to improve the deposition rate with less energy loss. The concentrated and steady plasma could be obtained device with higher gas pressure and relative lower microwave input power. Gas supply modes and inlet gas flow rate were optimized, which would be beneficial to synthesize the film with good quality.
基金Project(51878662)supported by the National Natural Science Foundation of ChinaProject(2017SK2420)supported by the Science and Technology of Hunan Province,ChinaProject(2019JJ20033)supported by the Distinguished Youth Natural Science Foundation of Hunan Province,China。
文摘In this study, a lab-scale upflow anaerobic sludge blanket(UASB) reactor was applied to studying the high-rate nitrogen removal of granule-based anammox process. The nitrogen removal rate(NRR) finally improved to 15.77 kg/m3/d by shortening hydraulic retention time(HRT) to 1.06 h. Well-shaped red anammox granules were extensively enriched inside the reactor. The results of nitrogen removal kinetics indicated that the present bioreactor has great nitrogen removal potential, because the maximum rate of substrate utilization(Umax) predicted by Stover-Kincannon model is suggested as 55.68 kg/(m3·d). Analysis of the microbial community showed that the anammox genus Candidatus Kuenenia dominated the bacterial communities. The relative abundance of Candidatus Kuenenia rose from 12.29% to 36.95% after progressively shorter HRT and higher influent substrate concentrations, illustrating the stability of nitrogen removal performance and biomass enrichment offered by the UASB in carrying out high-rate anammox process.
基金Project(CDJZR11210009) supported by the Fundamental Research Funds for the Central Universities of China
文摘Combined technology of SDS-CuO/TiO2 photocatalysis and sequencing batch reactor （SBR） were applied to treating dyestuff wastewater. Photocatalysis was carried out in a spiral up-flow type reactor as pre-treatment. SDS-CuO/TiO2 photocatalyst was prepared by modification of nano-TiO2 using CuO and sodium dodecyl sulfate （SDS）. Results show that the SDS-CuO/TiO2 photocatalyst contains two kinds of crystals, including TiO2 and CuO. The band gap of this photocatalyst is 1.56 eV, indicating that it can be excited by visible light （2〈794.87 nm）. And characterization also shows that there are alkyl groups on its surface. It takes 40 rain to improve the biodegradability of dyestuff wastewater. Five-day biochemical oxygen demand （BODs） and dehydrogenase activity （DHA） of wastewater reach the maximum value when dissolved oxygen is higher than 2.97 mg/L. SBR reactor was used to treat this biodegradability improved wastewater. Chemical oxygen demand （COD） and colority decline to 72 mg/L and 20 times, respectively, when the sludge loading is 0.179 kg（COD）/[kg（MLSS）＇d], dissolved oxygen is 4.09 mg/L and aeration time is 10 h.
基金Projects(ZR2013BL010,ZR2012DL05)supported by the Natural Science Foundation of Shandong Province,ChinaProject(4041412016)supported by the Research Excellence Award of Shandong University of Technology,ChinaProjects(2013GG03116,2011GG02115)supported by the Science and Technology Development Planning Project of Zibo,China
文摘High salinity industrial wastewater is difficult to treat using biological treatment system because of the high concentrations of salt.The potential of a sequencing batch biofilm reactor(SBBR)process in treating synthetic high salinity wastewater was evaluated at laboratory scale during a 110-day operation.The reactor was operated in a 12 h cycle,and each cycle consisted of 0.25 h influent addition,8 h aeration,3 h anoxic reaction,0.5 h sedimentation and 0.25 h effluent withdrawal.Gradual increase in salinity gradient was applied during the acclimatization period.The acclimated SBBR system was demonstrated to be an effective process to remove organic compounds and ammonia nitrogen under high salinity conditions with chemical oxygen demand(COD)and ammonia nitrogen(NH3-N)removal efficiencies of 88% and 80%,respectively.The microscopic examination indicated that rather than rotifers or vorticella,the zoogloea,filamentous fungus mingled with a small quantity of swimming infusorians were dominant bacteria in SBBR system.The removal efficiencies close to 80% in COD and 75% in NH3-N were achieved at an organic loading rate(OLR)of 0.96 kg COD/(m3·d),pH of 7.0,salinity of 14 g/L and NH3-N of 30 mg/L.
基金Project(51276131)supported by the National Natural Science Foundation of ChinaProject(ZRZ0316)supported by the Natural Science Foundation of Hubei Province,ChinaProject(2013070104010025)supported by the Morning Glory Project of Wuhan Science and Technology Bureau,China
文摘The mixing time of impact zone in liquid-continuous impinging streams reactor(LISR) is theoretically calculated by empirical model and modern micromixing model of the fluid mixing process, and the variation laws of macromixing time and micromixing time are quantitatively discussed. The results show that under a continuous and stable operating condition, as the paddle speed increases, the macromixing time and micromixing time calculated by the two models both decrease, even in a linkage equilibrium state. Simultaneously, as the paddle speed increases, the results figured by the two models tend to be consistent. It indicates that two models both are more suitable for calculation of mixing time in high paddle speed. Compared with the existing experimental results of this type of reactor, the mixing time computed in the speed of 1500 r/min is closer to it. These conclusions can provide an important reference for systematically studying the strengthening mechanism of LISR under continuous mixing conditions.
基金Project(2006AA06Z318) supported by the National High-Tech Research and Development Program of China
文摘The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor （SBR）, and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances （EPS） of sludge samples were extracted and analyzed during the granulation and storage process. The results show that the contents of protein and EPS increase along with the granulation process, while polysaccharides remain almost unchanged. The content of protein in EPS is almost two-fold larger than that of polysaccharides in granular sludge cultivated with municipal wastewater. Moreover, some of the granules disintegrate during storage, corresponding to the decrease of protein contents in EPS. Three peaks are identified in three-dimensional excitation emission matrix （EEM） fluorescence spectra of the EPS in the aerobic granules. Two peaks （A and B） are attributed to the protein-like fluorophores, and the third （peak C） is related to visible fulvic-like substances. Peak A gradually disappears during storage, while a new peak related to ultraviolet fulvic acid （peak D） is formed. The formation and the stability of aerobic granules are closely dependent on the quantity and composition of EPS proteins. Peak C has no obvious changes during granulation, while the fulvic-like substances present an increase in fluorescence intensities during storage, accompanied with an increase in structural complexity. The fulvie-like substances are also associated with the disintegration of the aerobic granules.
文摘The start-up of external circulationadded internal circulation(IC) reactor was finished in 26 d, 32 d fewer than that of IC reactor. To evaluate the influence of the added external circulation on the development of granular sludge, the characteristics of the granular sludge taken from the two tested laboratory-scale reactors during start-up were studied. The results show that the added external circulation can enhance biomass granulation, accelerate granule development and improve sludge characteristics. At the end of start-up, the granular size of sludge in external circulation-added IC reactor greatly increases with a size distribution much better than that of sludge in IC reactor. The granular sludge originated from external circulationadded IC reactor contains more extracellular polymers and has a greater settling velocity than that from IC reactor. Methanogenic activity of the granular sludge from the external circulationadded IC reactor started 26 d ago reaches 358.23mL·g -1 ·d -1 , 1.66 and 1.20 times as great as that of the sludge from the IC reactor started 26 d and 58 d ago respectively.
基金Projects(61376076,61274026,61377024)supported by the National Natural Science Foundation of ChinaProjects(12C0108,13C321)supported by the Scientific Research Fund of Hunan Provincial Education Department,ChinaProjects(2013FJ2011,2013FJ4232)supported by the Science and Technology Plan of Hunan Province,China
文摘Metal organic chemical vapor deposition(MOCVD) is a key equipment in the manufacturing of semiconductor optoelectronic devices and microwave devices in industry. Heating system is a vital part of MOCVD. Specific heating device and thermal control technology are needed for each new reactor design. By using resistance-wire heating MOCVD reaction chamber model, thermal analysis and structure optimization of the reactor were developed from the vertical position and the distance between coils of the resistance-wire heater. It is indicated that, within a certain range, the average temperature of the graphite susceptor varies linearly with the vertical distance of heater to susceptor, and with the changed distances between the coils; furthermore, single resistance-wire heater should be placed loosely in the internal and tightly in the external. The modulate accuracy of the temperature field approximately equals the change of the average temperature corresponding to the change of the coil position.
基金Project(NCET-05-0413)support by the Program for New Century Excellent Talents in UniversityProject(YB0142112) support by Priming Foundation of East China University of Science and Technology
文摘The Daubechies second order wavelet was applied to decompose pressure fluctuation signals with the gas flux varying from 0.18 to 0.90 m3/h and the solid mass fraction from 0 to 20% and scales 1?9 detail signals and the 9th scale approximation signals. The pressure signals were studied by multi-scale and R/S analysis method. Hurst analysis method was applied to analyze multi-fractal characteristics of different scale signals. The results show that the characteristics of mono-fractal under scale 1 and scale 2, and bi-fractal under scale 3?9 are effective in deducing the hydrodynamics in slurry bubbling flow system. The measured pressure signals are decomposed to micro-scale signals, meso-scale signals and macro-scale signals. Micro-scale and macro-scale signals are of mono-fractal characteristics, and meso-scale signals are of bi-fractal characteristics. By analyzing energy distribution of different scale signals,it is shown that pressure fluctuations mainly reflects meso-scale interaction between the particles and the bubble.
文摘PVA/ Chitosan (CS) composite membrane was studied in this paper, which could be used for enzyme processing of fat and oils. The parameters such as concentration of lipase, pH, and cross-linking agent as well as metal ions, which influence the immobilization of lipase in membrane, were optimized. The immobilized lipase was 0.66 u/cm2 and the recovery of immobilized lipase activity was 24%. The membrane reactor could be used to synthesize monoglyceride (MG) with many batches.
