Experiments on simultaneous absorption of SO_2 and NO_X from sintering flue gas via a composite absorbent NaClO_2/NaClO were carried out. The effects of various operating parameters such as NaClO_2 concentration(ms), ...Experiments on simultaneous absorption of SO_2 and NO_X from sintering flue gas via a composite absorbent NaClO_2/NaClO were carried out. The effects of various operating parameters such as NaClO_2 concentration(ms), NaClO concentration(mp), molar ratio of NaClO_2/NaClO(M), solution temperature(TR), initial solution pH, gas flow(Vg) and inlet concentration of SO_2(CS) and NO(CN) on the removal efficiencies of SO_2 and NO were discussed. The optimal experimental conditions were determined to be initial solution pH = 6, TR=55 °C and M = 1.3 under which the average efficiencies of desulfurization and denitrification could reach99.7% and 90.8%, respectively. Moreover, according to the analysis of reaction products, it was found that adding NaClO to NaClO_2 aqueous solution is favorable for the generation of ClO_2 and Cl_2 which have significant effect on desulfurization and denitrification. Finally, engineering experiments were performed and obtained good results demonstrating that this method is practicable and promising.展开更多
The highly active absorbent with oxidization based on fly ash, lime and additive was prepared. Experiments of simultaneous desulfurization and denitrification were carried out using fixture bed and duct injection. The...The highly active absorbent with oxidization based on fly ash, lime and additive was prepared. Experiments of simultaneous desulfurization and denitrification were carried out using fixture bed and duct injection. The influencial factors for the absorptive capacity of the absorbent were studied. The absorptive capacities of 120.7 mg for SO 2 and 43.7 mg for NOx were achieved at a Ca/(S+N) molar ratio 1.2, respectively, corresponding removal efficiencies of 87% and 76%, while spent absorbent appeared in the form of dry powder. The optimal temperature and humidity of flue gas treated with this process were shown to be approximately 50℃, and 5% respectively. The mechanism of removal for SO 2 and NOx was investigated. In comparison with traditional dry FGD, this process appears to have lower cost, less complicated configuration and simpler disposal of used absorbent. The valuable references can be provided for industrial application by this process. The foreground of application will be vast in China and in the world.展开更多
A process of simultaneous desulfurization and denitrification of flue gas was conducted in this study.The flue gas containing 200 mg·m^-3NO,1000-4000 mg·m^-3SO(2,)3%-9%O(2)and 10%-20%CO(2)was first oxidized ...A process of simultaneous desulfurization and denitrification of flue gas was conducted in this study.The flue gas containing 200 mg·m^-3NO,1000-4000 mg·m^-3SO(2,)3%-9%O(2)and 10%-20%CO(2)was first oxidized b(y)O3 and then absorbed by ammonia in a bubbling reactor.Increasing the ammonia concentration or the SO2 content in flue gas can promote the absorption of NOx and extend the effective absorption time.On the contrary,both increasing the absorbent temperature or the O(2)content shorten the effective absorption time of NO((x.))The change of solution pH had substantial influence on NOx absorption.In the presence of CO(2)the NOx removal efficiency reached 89.2%when the absorbent temperature was raised to 60℃and the effective absorption time can be maintained for 8 h,which attribute to the buffering effect in the absorbent.Besides,both the addition of Na(2)S2 O3 and urea can promote the NOx removal efficiency when the absorbent temperature is 25℃and the addition of Na(2)S2 O3 had achieved better results.The advantage of adding Na(2)S2 O3 became less evident at higher absorbent temperature and coexistence of CO(2.)In all experiments,SO(2)removal efficiency was always above 99%,and it was basically not affected by the above factors.展开更多
Thiobacillus denitrificans, a kind of autotrophic facultative bacteria, can oxidize sulfide into elemental sulfur or sulfate when nitrate was adopted as its electron accepter and carbon dioxide as its carbon resource ...Thiobacillus denitrificans, a kind of autotrophic facultative bacteria, can oxidize sulfide into elemental sulfur or sulfate when nitrate was adopted as its electron accepter and carbon dioxide as its carbon resource under anoxic or anaerobic environment. In this way, nitrate is converted into nitrogen. In addition, Thiobacillus denitrificans can accumulate sulfur extracellularly. In this study, in a process of simultaneous desulfurization and denitrification, a strain of Thiobacillus denitrificans is employed as sulfur-producer in the treatment of wastewater containing sulfide and nitrate. The key factors affecting this process are investigated through batch tests. The experimental results indicate that the sulfide concentration and the ratio of sulfide to nitrate (S^2-/NO3^-) in the influent are the key factors, and their suitable values are suggested to be 5/3 and no more than 300mg·L^-1, respectively, in order to achieve high conversion of sulfur.展开更多
An anaerobic expanding-bed reactor was adopted to investigate the feasibility of an innovative integrated process of simultaneous desulfurization and denitrification (SDD) for high strength wastewater. In the reactor,...An anaerobic expanding-bed reactor was adopted to investigate the feasibility of an innovative integrated process of simultaneous desulfurization and denitrification (SDD) for high strength wastewater. In the reactor, heterotrophic bacteria (including sulfate reducing bacterium and denitrifying bacteria) and autotrophic bacteria (including Thiobacillus denitrificans) cooperated together by incubating and enriching functional bacteria on different carriers in the anaerobic activated sludge. Synthetic wastewater with high concentrations of sulfate and nitrate was employed. The experimental results showed that the removal efficiency of sulfate and nitrate was above 85%, elemental sulfur was observed while nitrate was absent in effluent. The balance of sulfur, nitrogen and electron was discussed respectively, which indicated that the integrated SDD process could be actualized. These results might provide a guidance to further investigate the key factors affecting the integrated SDD process and to improve the efficiency of desulfurization and denitrification in wastewater treatment.展开更多
In this study, simultaneous nitrification and autotrophic denitrification (SNAD) with either elemental sulfur or pyrite were investigated in fluidized bed reactors in mesophilic conditions. The reactor performance was...In this study, simultaneous nitrification and autotrophic denitrification (SNAD) with either elemental sulfur or pyrite were investigated in fluidized bed reactors in mesophilic conditions. The reactor performance was evaluated at different ammonium (12-40 mg/L of NH4+-N), nitrate (35-45 mg/L of NO3--N), and dissolved oxygen (DO) (0.1-1.5 mg/L) concentrations, with a hydraulic retention time of 12 h. The pyrite reactor supported the SNAD process with a maximum nitrogen removal efficiency of 139.5 mg/(L·d) when the DO concentration was in the range of 0.8-1.5 mg/L. This range, however, limited the denitrification efficiency of the reactor, which decreased from 90.0% ± 5.3% in phases II-V to 67.9% ± 7.2% in phases VI and VII. Sulfate precipitated as iron sulfate (FeSO4/Fe2(SO4)3) and sodium sulfate (Na2SO4) minerals during the experiment. The sulfur reactor did not respond well to nitrification with a low and unstable ammonium removal efficiency, while denitrification occurred with a nitrate removal efficiency of 97.8%. In the pyrite system, the nitrifying bacterium Nitrosomonas sp. was present, and its relative abundance increased from 0.1% to 1.1%, while the autotrophic denitrifying genera Terrimonas, Ferruginibacter, and Denitratimonas dominated the community. Thiobacillus, Sulfurovum, and Trichlorobacter were the most abundant genera in the sulfur reactor during the entire experiment.展开更多
Based on the TiO2 photocatalysis mechanism, a new method of simultaneous desulfurization and denitrification from flue gas was proposed. Preparation of TiO2 photocatalyst, design of photocatalysis reactor and influenc...Based on the TiO2 photocatalysis mechanism, a new method of simultaneous desulfurization and denitrification from flue gas was proposed. Preparation of TiO2 photocatalyst, design of photocatalysis reactor and influencing factors for simul- taneous removal of SO2 and NO, and removal mechanism of SO2 and NO were studied. After the optimal values of concentration of O2 in flue gas, the relative humidity of flue gas and the irradiation time in the photocatalysis reactor were used, the efficiencies of removal for SO2 and NO can be achieved above 98% and about 67%, respectively. According to the results of removal products analysis, the re- moval mechanism of SO2 and NO based on TiO2 photocatlysis can be put forward, namely, SO2 was oxidized to SO3 partly, the bulk of NO was oxidized to NO2, and both were removed by resorbing finally.展开更多
The oxidizing highly reactive absorbent was prepared from fly ash,industry lime,and an oxidizing additive M.Experiments of simultaneous desulfurization and denitrification were carried out in a flue gas circulating fl...The oxidizing highly reactive absorbent was prepared from fly ash,industry lime,and an oxidizing additive M.Experiments of simultaneous desulfurization and denitrification were carried out in a flue gas circulating fluidized bed(CFB).The effects of influencing factors and calcium availability were also investigated on the removal efficiencies of desulfurization and denitrification.Removal efficiencies of 95.5%for SO2 and 64.8%for NO were obtained respectively under the optimal experimental conditions. The component of the spent absorbent was analyzed with chemical analysis methods.The results in- dicated that more nitrogen species appeared in the spent absorbent except sulfur species.A scanning electron microscope(SEM)and an accessory X-ray energy spectrometer were used to observe micro-properties of the samples,including fly ash,oxidizing highly reactive absorbent and spent absorbent.The simultaneous removal mechanism of SO2 and NO based on this absorbent was pro- posed according to the experimental results.展开更多
With the vigorous development of China's iron and steel industry and the introduction of ultra-low emission policies,the emission of pollutants such as SO_(2)and NO x has received unprecedented attention.Consideri...With the vigorous development of China's iron and steel industry and the introduction of ultra-low emission policies,the emission of pollutants such as SO_(2)and NO x has received unprecedented attention.Considering the increase of the proportion of semi-dry desulfurization technology in the desulfurization process,several semi-dry desulphurization technologies such as flue gas circulating fluidized bed(CFB),dense flow absorber(DFA)and spray drying absorption(SDA)are briefly summarized.Moreover,a method for simultaneous treatment of SO_(2)and NOx in sintering/pelletizing flue gas by O_(3)oxidation combined with semidry method is introduced.Meantime,the effects of key parameters such as O_(3)/NO molar ratio,Ca SO_(3),SO_(2),reaction temperature,Ca/(S+2 N)molar ratio,droplet size and approach to adiabatic saturation temperature(AAST)on denitrification and desulfurization are analyzed.Furthermore,the reaction mechanism of denitrification and desulfurization is further elucidated.Finally,the advantages and development prospects of the new technology are proposed.展开更多
The effects of chemical oxygen demand and nitrogen(COD/N)ratio and dissolved oxygen concentration(DO)on simultaneous nitrification and denitrification(SND)were investigated using an airlift internal circulation membra...The effects of chemical oxygen demand and nitrogen(COD/N)ratio and dissolved oxygen concentration(DO)on simultaneous nitrification and denitrification(SND)were investigated using an airlift internal circulation membrane bioreactor(AIC-MBR)with synthetic wastewater.The results showed that the COD efficiencies were consistently greater than 90% regardless of changes in the COD/N ratio.At the COD/N ratio of 4.77 and 10.04,the system nitrogen removal efficiency became higher than 70%.However,the nitrogen rem...展开更多
Simultaneous removal of SO2 and NO from flue gas by the highly active absorbent prepared from fly ash, lime and a few oxidizing manganese compound add itive was studied using a flue gas circulating fluidized bed(CFB) ...Simultaneous removal of SO2 and NO from flue gas by the highly active absorbent prepared from fly ash, lime and a few oxidizing manganese compound add itive was studied using a flue gas circulating fluidized bed(CFB) under differen t experimental conditions. The effects influencing the removal effiencies were d iscussed. The optimal flue gas temperature, flue gas humidity, gas velocity of C FB and Ca/( S+N) molar ratio with this process were approximately 110℃, 6%, 1.8 m/s and 1.05, respectively. Removal efficiencies of 92.3% for SO2 and 60.88% fo r NO were obtained under the optimal experimental conditions. While the spent ab sorbent appeared in the form of dry powder, the mechanism of removal for SO2 and NO based on the highly active absorbent was investigated by a scanning electron microscope(SEM), a X-ray energy spectrometer and the chemical analysis methods. The valuable references can be provided for industrial application by the proce ss. The foreground of application will be vast in China and in the world.展开更多
The characteristic studies, by means of LR, UV-Vis and XPS spectroscopies, of the preparation process of Mo-Co-S and Mo-Fe-S catalysts for HDS and HDN, derived from (NH4)2MoS4-CoCl2 and (NH4)2MoS4-FeCl2 complexes supp...The characteristic studies, by means of LR, UV-Vis and XPS spectroscopies, of the preparation process of Mo-Co-S and Mo-Fe-S catalysts for HDS and HDN, derived from (NH4)2MoS4-CoCl2 and (NH4)2MoS4-FeCl2 complexes supported on γ-Al2O3, respectively, indicate that the catalytically essential moiety on the surface of the catalysts is dominantly some sulfido-bimetallic species with such a structural unit (M’ =Co or Fe), and both Co and Fe, served as promoters, can donate electrons to Mo probably via bridging-S. The nature of active-sites and the mechanism of promotion are discussed according to the results.展开更多
A new wastewater treatment facility—lateral flow biological aerated filter (LBAF) was developed aiming at solving energy consumption and operational problems in wastewater treatment facilities in small towns. It has ...A new wastewater treatment facility—lateral flow biological aerated filter (LBAF) was developed aiming at solving energy consumption and operational problems in wastewater treatment facilities in small towns. It has the function of nitrification and removing organic substrate. In this study, we focused on the denitrification performance of LBAF and its possible mechanism under thorough aeration. We identified the existence of simultaneous nitrification and denitrification (SND) by analyzing nitrogenous compounds along the flow path of LBAF and supportive microbial microscopy, and studied the effects of air/water ratio and hydraulic loading on the performance of nitrogen removal and on SND in LBAF to find out the optimal operation condition. It is found that for saving operation cost, aeration can be reduced to some degree that allows desirable removal efficiency of pollutants, and the optimal air/water ratio is 10:1. Hydraulic loading less than 0.43 m h?1 hardly affects the nitrification and denitrification performance; whereas higher hydraulic loading is unfavorable to both nitrification and denitrification, far more unfavorable to denitrification than to nitrification.展开更多
CeO2/γ-Al2O3, La2O3/γ-Al2O3, CeO2-La2O3/γ-Al2O3 and CeO2-La2O3, which were prepared by impregnating in certain ratio, were used as the catalysts for the reduction of SO2 and NO by CO. Separate and simultaneous remo...CeO2/γ-Al2O3, La2O3/γ-Al2O3, CeO2-La2O3/γ-Al2O3 and CeO2-La2O3, which were prepared by impregnating in certain ratio, were used as the catalysts for the reduction of SO2 and NO by CO. Separate and simultaneous removal of SO2 and NO over La2O3/γ-Al2O3, CeO2/γ-Al2O3, CeO2-La2O3/γ-Al2O3 were investigated. The phase characteristics of catalysts were also analyzed by X-ray diffraction. The result shows that the conversions of SO2 and NO are above 98% over CeO2/γ-Al2O3 and CeO2-La2O3/γ-Al2O3. After SO2 is added in the NO-CO-N2 system （NO∶SO2=1∶2～1∶3）, the conversions of SO2 and NO are both above 98%. Furthermore, it is found that CeO2-La2O3 with various ratios has different activity for the simultaneous reduction of SO2 and NO.展开更多
基金Supported by the National Science Foundation of China for Distinguished Young Scholars(No.51325601)Major Program of National Science Foundation of China(No.51390492)Joint Funds of National Science Foundation of China(No.U1560205)
文摘Experiments on simultaneous absorption of SO_2 and NO_X from sintering flue gas via a composite absorbent NaClO_2/NaClO were carried out. The effects of various operating parameters such as NaClO_2 concentration(ms), NaClO concentration(mp), molar ratio of NaClO_2/NaClO(M), solution temperature(TR), initial solution pH, gas flow(Vg) and inlet concentration of SO_2(CS) and NO(CN) on the removal efficiencies of SO_2 and NO were discussed. The optimal experimental conditions were determined to be initial solution pH = 6, TR=55 °C and M = 1.3 under which the average efficiencies of desulfurization and denitrification could reach99.7% and 90.8%, respectively. Moreover, according to the analysis of reaction products, it was found that adding NaClO to NaClO_2 aqueous solution is favorable for the generation of ClO_2 and Cl_2 which have significant effect on desulfurization and denitrification. Finally, engineering experiments were performed and obtained good results demonstrating that this method is practicable and promising.
文摘The highly active absorbent with oxidization based on fly ash, lime and additive was prepared. Experiments of simultaneous desulfurization and denitrification were carried out using fixture bed and duct injection. The influencial factors for the absorptive capacity of the absorbent were studied. The absorptive capacities of 120.7 mg for SO 2 and 43.7 mg for NOx were achieved at a Ca/(S+N) molar ratio 1.2, respectively, corresponding removal efficiencies of 87% and 76%, while spent absorbent appeared in the form of dry powder. The optimal temperature and humidity of flue gas treated with this process were shown to be approximately 50℃, and 5% respectively. The mechanism of removal for SO 2 and NOx was investigated. In comparison with traditional dry FGD, this process appears to have lower cost, less complicated configuration and simpler disposal of used absorbent. The valuable references can be provided for industrial application by this process. The foreground of application will be vast in China and in the world.
基金financially supported by the National Key Research and Development Program of China(2016YFB0600701)。
文摘A process of simultaneous desulfurization and denitrification of flue gas was conducted in this study.The flue gas containing 200 mg·m^-3NO,1000-4000 mg·m^-3SO(2,)3%-9%O(2)and 10%-20%CO(2)was first oxidized b(y)O3 and then absorbed by ammonia in a bubbling reactor.Increasing the ammonia concentration or the SO2 content in flue gas can promote the absorption of NOx and extend the effective absorption time.On the contrary,both increasing the absorbent temperature or the O(2)content shorten the effective absorption time of NO((x.))The change of solution pH had substantial influence on NOx absorption.In the presence of CO(2)the NOx removal efficiency reached 89.2%when the absorbent temperature was raised to 60℃and the effective absorption time can be maintained for 8 h,which attribute to the buffering effect in the absorbent.Besides,both the addition of Na(2)S2 O3 and urea can promote the NOx removal efficiency when the absorbent temperature is 25℃and the addition of Na(2)S2 O3 had achieved better results.The advantage of adding Na(2)S2 O3 became less evident at higher absorbent temperature and coexistence of CO(2.)In all experiments,SO(2)removal efficiency was always above 99%,and it was basically not affected by the above factors.
基金Supported by the National Natural Science Foundation of China (No. 50208006).
文摘Thiobacillus denitrificans, a kind of autotrophic facultative bacteria, can oxidize sulfide into elemental sulfur or sulfate when nitrate was adopted as its electron accepter and carbon dioxide as its carbon resource under anoxic or anaerobic environment. In this way, nitrate is converted into nitrogen. In addition, Thiobacillus denitrificans can accumulate sulfur extracellularly. In this study, in a process of simultaneous desulfurization and denitrification, a strain of Thiobacillus denitrificans is employed as sulfur-producer in the treatment of wastewater containing sulfide and nitrate. The key factors affecting this process are investigated through batch tests. The experimental results indicate that the sulfide concentration and the ratio of sulfide to nitrate (S^2-/NO3^-) in the influent are the key factors, and their suitable values are suggested to be 5/3 and no more than 300mg·L^-1, respectively, in order to achieve high conversion of sulfur.
基金Sponsored by the New Century Distinguished Experts Supporting Program (Grant No 2005601310)
文摘An anaerobic expanding-bed reactor was adopted to investigate the feasibility of an innovative integrated process of simultaneous desulfurization and denitrification (SDD) for high strength wastewater. In the reactor, heterotrophic bacteria (including sulfate reducing bacterium and denitrifying bacteria) and autotrophic bacteria (including Thiobacillus denitrificans) cooperated together by incubating and enriching functional bacteria on different carriers in the anaerobic activated sludge. Synthetic wastewater with high concentrations of sulfate and nitrate was employed. The experimental results showed that the removal efficiency of sulfate and nitrate was above 85%, elemental sulfur was observed while nitrate was absent in effluent. The balance of sulfur, nitrogen and electron was discussed respectively, which indicated that the integrated SDD process could be actualized. These results might provide a guidance to further investigate the key factors affecting the integrated SDD process and to improve the efficiency of desulfurization and denitrification in wastewater treatment.
基金supported by the Science Foundation Ireland(SFI)through the SFI Research Professorship Programme entitled"Innovative Energy Technologies for Biofuels,Bioenergy and a Sustainable Irish Bioeconomy"(IETSBIO3Grant No.15/RP/2763)the Research Infrastructure Research Grant Platform for Biofuel Analysis(Grant No.16/RI/3401).
文摘In this study, simultaneous nitrification and autotrophic denitrification (SNAD) with either elemental sulfur or pyrite were investigated in fluidized bed reactors in mesophilic conditions. The reactor performance was evaluated at different ammonium (12-40 mg/L of NH4+-N), nitrate (35-45 mg/L of NO3--N), and dissolved oxygen (DO) (0.1-1.5 mg/L) concentrations, with a hydraulic retention time of 12 h. The pyrite reactor supported the SNAD process with a maximum nitrogen removal efficiency of 139.5 mg/(L·d) when the DO concentration was in the range of 0.8-1.5 mg/L. This range, however, limited the denitrification efficiency of the reactor, which decreased from 90.0% ± 5.3% in phases II-V to 67.9% ± 7.2% in phases VI and VII. Sulfate precipitated as iron sulfate (FeSO4/Fe2(SO4)3) and sodium sulfate (Na2SO4) minerals during the experiment. The sulfur reactor did not respond well to nitrification with a low and unstable ammonium removal efficiency, while denitrification occurred with a nitrate removal efficiency of 97.8%. In the pyrite system, the nitrifying bacterium Nitrosomonas sp. was present, and its relative abundance increased from 0.1% to 1.1%, while the autotrophic denitrifying genera Terrimonas, Ferruginibacter, and Denitratimonas dominated the community. Thiobacillus, Sulfurovum, and Trichlorobacter were the most abundant genera in the sulfur reactor during the entire experiment.
文摘Based on the TiO2 photocatalysis mechanism, a new method of simultaneous desulfurization and denitrification from flue gas was proposed. Preparation of TiO2 photocatalyst, design of photocatalysis reactor and influencing factors for simul- taneous removal of SO2 and NO, and removal mechanism of SO2 and NO were studied. After the optimal values of concentration of O2 in flue gas, the relative humidity of flue gas and the irradiation time in the photocatalysis reactor were used, the efficiencies of removal for SO2 and NO can be achieved above 98% and about 67%, respectively. According to the results of removal products analysis, the re- moval mechanism of SO2 and NO based on TiO2 photocatlysis can be put forward, namely, SO2 was oxidized to SO3 partly, the bulk of NO was oxidized to NO2, and both were removed by resorbing finally.
基金the Significant Pre-research Foundation of North China Electric PowerUniversity(D03-035)
文摘The oxidizing highly reactive absorbent was prepared from fly ash,industry lime,and an oxidizing additive M.Experiments of simultaneous desulfurization and denitrification were carried out in a flue gas circulating fluidized bed(CFB).The effects of influencing factors and calcium availability were also investigated on the removal efficiencies of desulfurization and denitrification.Removal efficiencies of 95.5%for SO2 and 64.8%for NO were obtained respectively under the optimal experimental conditions. The component of the spent absorbent was analyzed with chemical analysis methods.The results in- dicated that more nitrogen species appeared in the spent absorbent except sulfur species.A scanning electron microscope(SEM)and an accessory X-ray energy spectrometer were used to observe micro-properties of the samples,including fly ash,oxidizing highly reactive absorbent and spent absorbent.The simultaneous removal mechanism of SO2 and NO based on this absorbent was pro- posed according to the experimental results.
基金supported by the National Key Research and Development Program of China(No.2017YFC0210600)the National Natural Science Foundation of China(No.51978644)。
文摘With the vigorous development of China's iron and steel industry and the introduction of ultra-low emission policies,the emission of pollutants such as SO_(2)and NO x has received unprecedented attention.Considering the increase of the proportion of semi-dry desulfurization technology in the desulfurization process,several semi-dry desulphurization technologies such as flue gas circulating fluidized bed(CFB),dense flow absorber(DFA)and spray drying absorption(SDA)are briefly summarized.Moreover,a method for simultaneous treatment of SO_(2)and NOx in sintering/pelletizing flue gas by O_(3)oxidation combined with semidry method is introduced.Meantime,the effects of key parameters such as O_(3)/NO molar ratio,Ca SO_(3),SO_(2),reaction temperature,Ca/(S+2 N)molar ratio,droplet size and approach to adiabatic saturation temperature(AAST)on denitrification and desulfurization are analyzed.Furthermore,the reaction mechanism of denitrification and desulfurization is further elucidated.Finally,the advantages and development prospects of the new technology are proposed.
文摘The effects of chemical oxygen demand and nitrogen(COD/N)ratio and dissolved oxygen concentration(DO)on simultaneous nitrification and denitrification(SND)were investigated using an airlift internal circulation membrane bioreactor(AIC-MBR)with synthetic wastewater.The results showed that the COD efficiencies were consistently greater than 90% regardless of changes in the COD/N ratio.At the COD/N ratio of 4.77 and 10.04,the system nitrogen removal efficiency became higher than 70%.However,the nitrogen rem...
基金the National Key Project of Scientific and Technical Supporting Program of Ministry of Science and Technology ofChina(2006BAC19B03)Academic Human Resources Development in Institutions of Higher Leading under the Jurisdiction ofBeijing Municipalitythe Specialized Research Fund for the Doctoral Program of Higher Education of China(20060005002).
基金Project supported by the Key International Cooperative Program of NSFC(No. 50521140075)the Hi-Tech Research and Development Program(863)of China(No. 2004AA601020)the Attached Projects of"863"Project of Beijing Municipal Science and Technology(No.20005186040421).
基金TheSignificantPre-researchFoundationofN orthChinaElectricPow erU niversity(N o.93405301)
文摘Simultaneous removal of SO2 and NO from flue gas by the highly active absorbent prepared from fly ash, lime and a few oxidizing manganese compound add itive was studied using a flue gas circulating fluidized bed(CFB) under differen t experimental conditions. The effects influencing the removal effiencies were d iscussed. The optimal flue gas temperature, flue gas humidity, gas velocity of C FB and Ca/( S+N) molar ratio with this process were approximately 110℃, 6%, 1.8 m/s and 1.05, respectively. Removal efficiencies of 92.3% for SO2 and 60.88% fo r NO were obtained under the optimal experimental conditions. While the spent ab sorbent appeared in the form of dry powder, the mechanism of removal for SO2 and NO based on the highly active absorbent was investigated by a scanning electron microscope(SEM), a X-ray energy spectrometer and the chemical analysis methods. The valuable references can be provided for industrial application by the proce ss. The foreground of application will be vast in China and in the world.
基金Supported by the National Natural Science Foundation of China
文摘The characteristic studies, by means of LR, UV-Vis and XPS spectroscopies, of the preparation process of Mo-Co-S and Mo-Fe-S catalysts for HDS and HDN, derived from (NH4)2MoS4-CoCl2 and (NH4)2MoS4-FeCl2 complexes supported on γ-Al2O3, respectively, indicate that the catalytically essential moiety on the surface of the catalysts is dominantly some sulfido-bimetallic species with such a structural unit (M’ =Co or Fe), and both Co and Fe, served as promoters, can donate electrons to Mo probably via bridging-S. The nature of active-sites and the mechanism of promotion are discussed according to the results.
基金Funded by the National Key Technologies R & D Program of China During the 10th Five-Year Plan Periods of China (No.2001BA604A01-03).
文摘A new wastewater treatment facility—lateral flow biological aerated filter (LBAF) was developed aiming at solving energy consumption and operational problems in wastewater treatment facilities in small towns. It has the function of nitrification and removing organic substrate. In this study, we focused on the denitrification performance of LBAF and its possible mechanism under thorough aeration. We identified the existence of simultaneous nitrification and denitrification (SND) by analyzing nitrogenous compounds along the flow path of LBAF and supportive microbial microscopy, and studied the effects of air/water ratio and hydraulic loading on the performance of nitrogen removal and on SND in LBAF to find out the optimal operation condition. It is found that for saving operation cost, aeration can be reduced to some degree that allows desirable removal efficiency of pollutants, and the optimal air/water ratio is 10:1. Hydraulic loading less than 0.43 m h?1 hardly affects the nitrification and denitrification performance; whereas higher hydraulic loading is unfavorable to both nitrification and denitrification, far more unfavorable to denitrification than to nitrification.
基金Project supportd bythe National Natural Science Foundation of China (50237010)
文摘CeO2/γ-Al2O3, La2O3/γ-Al2O3, CeO2-La2O3/γ-Al2O3 and CeO2-La2O3, which were prepared by impregnating in certain ratio, were used as the catalysts for the reduction of SO2 and NO by CO. Separate and simultaneous removal of SO2 and NO over La2O3/γ-Al2O3, CeO2/γ-Al2O3, CeO2-La2O3/γ-Al2O3 were investigated. The phase characteristics of catalysts were also analyzed by X-ray diffraction. The result shows that the conversions of SO2 and NO are above 98% over CeO2/γ-Al2O3 and CeO2-La2O3/γ-Al2O3. After SO2 is added in the NO-CO-N2 system （NO∶SO2=1∶2～1∶3）, the conversions of SO2 and NO are both above 98%. Furthermore, it is found that CeO2-La2O3 with various ratios has different activity for the simultaneous reduction of SO2 and NO.
