The residue from a second-stage dry sinter plant off-gas cleaning process contains both the fine dust from the sinter plant and the sorbent used. Recycling of the material that is usually handled by landfills to the s...The residue from a second-stage dry sinter plant off-gas cleaning process contains both the fine dust from the sinter plant and the sorbent used. Recycling of the material that is usually handled by landfills to the sinter plant feed is not possible because of its chloride con- tent. Leaching of the chlorides allow the recycling of remaining solids. The saline leachate produced contains some heavy metals and must be treated before it is discharged into the sea. In laboratory experiments, leaching tests with the subsequent treatment of the leachate were con- ducted. After the process was optimized, all heavy-metal concentrations were below the permissible values. The optimum treatment condi- tions for heavy-metal precipitation were observed to be the filtration of the suspended solids followed by the dosing of liquid with lime milk （pH 10） and the subsequent precipitation using sodium sulfide.展开更多
The first imported off-gas analysis system on 150 t BOF at Benxi Plates Co.Ltd. is presented and the continuous determination of bath carbon content has been studied. Thecomparison between the whole-course carbon inte...The first imported off-gas analysis system on 150 t BOF at Benxi Plates Co.Ltd. is presented and the continuous determination of bath carbon content has been studied. Thecomparison between the whole-course carbon integral model and the end-point carbon prediction modelhas been made. The results show that the regular change of CO, CO_2 and N_2 content in the off-gasduring blowing plays an important role in judging the smelting end-point of converter; the cubiccurve fitting model has a higher hit rate over 95 percent for the heats whose end-point carboncontent is lower than 0.10 percent with a precision of +-0.02 percent and has a large error for theheats whose end-point carbon content is more than 0.15 percent.展开更多
In copper sulfide concentrates smelting, the off-gases from the Pierce Smith converter (PSC) furnace must be treated to prevent environmental impacts as they are highly corrosive and toxic. The purpose of this researc...In copper sulfide concentrates smelting, the off-gases from the Pierce Smith converter (PSC) furnace must be treated to prevent environmental impacts as they are highly corrosive and toxic. The purpose of this research project is to present a methodology for the simulation of a capture and cooling system of the smelting off-gases from a Pierce Smith copper converter, using computational fluid dynamics. Through this methodology, it is possible to obtain a simulation model of the smelting off-gases behavior with an average error of 9.88%. Basically, it demonstrates that the simulated tendencies of the metallurgical off-gases on the cooling hood and chamber can be reliable to predict the thermo-fluid dynamic behavior of the off-gases inside the studied off-gases handling system.展开更多
Looking back at over a decade of research by herself and her group,the author advocates the added value of gas phase measurements and the application of mass balances,as well as the synergetic benefits obtained when c...Looking back at over a decade of research by herself and her group,the author advocates the added value of gas phase measurements and the application of mass balances,as well as the synergetic benefits obtained when combining both.The increased application of off-gas measurements for greenhouse gas emission monitoring offers a great opportunity to look at other components in the gas phase,particularly oxygen.Mass balances should not be strictly reserved for modellers but also prove useful while conducting lab experiments and studying full-scale measurement data.Combining off-gas measurements with mass balances may serve not only to quantify greenhouse gas emission factors and aeration efficiency but also to follow dynamic concentration profiles of dissolved components without dedicated sensors and/or to calculate other unmeasured variables.Mass-balance-based data reconciliation allows for obtaining reliable and accurate data,and even more when combined with off-gas analysis.展开更多
The biofilter is cost-effective for the waste gases treatment. The bacterial is the main microorganism in the conventional biofilters. However, it faces some problems on the elimination of hydrophobic compounds. In or...The biofilter is cost-effective for the waste gases treatment. The bacterial is the main microorganism in the conventional biofilters. However, it faces some problems on the elimination of hydrophobic compounds. In order to overcome these problems, the biofilters with fungi were developed. The objective of this study is to investigate the factors affecting ethyl mercaptan(EM)-degradation using a fungal biofilter. A laboratory experiment was set up. The effects of loading rate, empty bed residence times(EBRT) and pH on EM degradation were investigated. Over 95% removals of EM could be achieved, under the condition of the influent loadings below 50 g/(m·h). Removal efficiencies improved to 98% with EM loading decreased to 45 g/(m·h). For long EBRT of 58 s corresponding to a flow rate of 0.3 m3/h, the EM removal efficiencies of over 98% were observed. However, when EBRT was decreased to 14 s, the removal efficiencies fell under 80%. The pH range of 3—5 was feasible to fungi.展开更多
In the present study, a bubble generator and a bubble separator were designed and evaluated for an independent off-gas removal system of a small thorium molten salt reactor(TMSR) with reference to the design of the Oa...In the present study, a bubble generator and a bubble separator were designed and evaluated for an independent off-gas removal system of a small thorium molten salt reactor(TMSR) with reference to the design of the Oak Ridge National Laboratory(ONRL). The bubble generator employed a Venturi tube as its main body owing to its simplicity and highly reliable structure. A centrifugal separator was used as the bubble separator, taking advantage of the kinetic energy of fluid to create a centrifugal force to separate gas bubbles from the mixture flow. Both the bubble generator and the separator were demonstrated to have good potential to meet the performance requirements of an off-gas removal system for a small TMSR. With water and air as the working fluids, for the final designs of the two key pieces of equipment, a liquid flow rate exceeding 15 m3·h-1 can essentially make their performance meet the requirements of the off-gas removal system in terms of the average size of the generated bubbles and gas separation efficiency.展开更多
Sulfur dioxide（SO_2） and benzene homologs are frequently present in the off-gas during the process of sewage sludge drying. A laboratory scale biofilter was set up to co-treat SO_2 and o-xylene in the present study....Sulfur dioxide（SO_2） and benzene homologs are frequently present in the off-gas during the process of sewage sludge drying. A laboratory scale biofilter was set up to co-treat SO_2 and o-xylene in the present study. SO_2 and o-xylene could be removed simultaneously in a single biofilter. Their concentration ratio in the inlet stream influenced the removal efficiencies. It is worth noting that the removal of SO_2 could be enhanced when low concentrations of o-xylene were introduced into the biofilter. Pseudomonas sp., Paenibacillus sp., and Bacillus sp. were the main functional bacteria groups in the biofilter. Sulfur-oxidizing bacteria（SOB） and o-xylene-degrading bacteria（XB） thrived in the biofilter and their counts as well as their growth rate increased with the increase in amount of SO2 and o-xylene supplied. The microbial populations differed in counts and species due to the properties and components of the compounds being treated in the biofilter. The presence of mixed substrates enhanced the diversity of the microbial population. During the treatment process, bioaerosols including potentially pathogenic bacteria, e.g., Acinetobacter lwoffii and Aeromonas sp., were emitted from the biofilter. Further investigation is needed to focus on the potential hazards caused by the bioaerosols emitted from waste gas treatment bioreactors.展开更多
Direct separation of Xe and Kr from air or used nuclear fuel(UNF)off-gas by means of porous adsorbents is of industrial importance but is a very challenging task.In this work,we show a robust metal-organic framework(M...Direct separation of Xe and Kr from air or used nuclear fuel(UNF)off-gas by means of porous adsorbents is of industrial importance but is a very challenging task.In this work,we show a robust metal-organic framework(MOF),namely ECUT-60,which renders not only high chemical stability,but also unique structure with multiple traps.This leads to the ultrahigh Xe adsorption capacity,exceeding most reported porous materials.Impressively,this MOF also enables high selectivity of Xe over Kr,CO2,O2,and N2,leading to the high-performance separation for trace quantitites of Xe/Kr from a simulated UNF reprocessing off-gas.The separation capability has been demonstrated by using dynamic breakthrough experiments,giving the record Xe uptake up to 70.4 mmol/kg and the production of 19.7 mmol/kg pure Xe.Consequently,ECUT-60 has promising potential in direct production of Xe from UNF off-gas or air.The separation mechanism,as unveiled by theoretical calculation,is attributed to the multiple traps in ECUT-60 that affords rigid restrict for Xe atom via van der Waals force.展开更多
We investigated the correlation between performance and the bacteria community composition by H2S and toluene co-treatment. Operation of the bioreactor was divided into four stages, in which the inlet concentration of...We investigated the correlation between performance and the bacteria community composition by H2S and toluene co-treatment. Operation of the bioreactor was divided into four stages, in which the inlet concentration of toluene and H2S were gradually increased. In Stage I, toluene was the sole target compound with an average removal efficiency of 86.49%. After adding HeS in Stage II, removal efficiency of toluene decreased immediately and recovered gradually to 85.96%. When the inlet concentration of toluene and HzS was increased in Stage III and Stage IV, respectively, the average removal efficiency for toluene increased continuously from 86.31% to 87.24%. The elimination capacities of toluene increased with increasing inlet loading rates of toluene and H2S. Results of the PCR-DGGE analysis showed a turnover growth and decline of the microbial populations in the bioreactor. In Stage I, the dominant toluene-degrading bacteria mainly contained Pseudomonas sp. strain PS ＋ and Hydrogenophaga sp. In Stage IV, however, the dominant toluene-degrading bacteria was aciduric bacteria （Clostridium populeti）. The dominant microbial community in the bioreactor enhanced the elimination capacity of toluene, and adding H2S changed the environment of microbial growth, thus resulted in an evolution of dominant microorganisms. Analyses of microbial community and their activities provides valuable information to efficiently enhance simultaneous removal of toluene and H2S in the bioreactor.展开更多
Converter off-gas, an important energy resource for steel industries, is one of the weak points in the recov ery and utilization of secondary energy resources. To improve the level of recycling converter off-gas in st...Converter off-gas, an important energy resource for steel industries, is one of the weak points in the recov ery and utilization of secondary energy resources. To improve the level of recycling converter off-gas in steel plants, a novel approach to the recycle of CO2 separated from converter off-gas or other off-gas for the green slag splashing technique was developed, and the CO2 equilibrium conversion ratio of the green CO2 slag splashing under different technological conditions was calculated by the program of enthalpy （H）, entropy （S）, and heat capacity （C）, i.e. HSC software. Furthermore, the experiments of CO2 injected into molten converter slag were carried out, and the influencing factors of the green slag splashing technique using CO2 were analyzed. The experimental results showed that the carbon content for smooth slag splashing using COs was about 4.0%.展开更多
Knowledge of the oxygen mass transfer of aerators under operational conditions in a full-scale wastewater treatment plant （WWTP） is meaningful for the optimization of WWTP, however, scarce to best of our knowledge. ...Knowledge of the oxygen mass transfer of aerators under operational conditions in a full-scale wastewater treatment plant （WWTP） is meaningful for the optimization of WWTP, however, scarce to best of our knowledge. Through analyzing a plug flow aeration tank in the Lucun WWTP, in Wuxi, China, the oxygenation capacity of fine-bubble aerators under process conditions have been measured in- situ using the off-gas method and the non-steady-state method. The off-gas method demonstrated that the aerators in different corridors in the aeration tank of WWTP had significantly different oxygen transfer performance; furthermore, the aerators in the same corridor shared almost equal oxygen transfer performance over the course of a day. Results measured by the two methods showed that the oxygen transfer performance of fine-bubble aerators in the aeration tank decreased dramatically compared with that in the clean water. The loss of oxygen transfer coefficient was over 50% under low-aeration conditions （aeration amount 〈 0.67 Nm 3 /hr）. However, as the aeration amount reached 0.96 Nm 3 /hr, the discrepancy of oxygen transfer between the process condition and clean water was negligible. The analysis also indicated that the non-steady-state and off-gas methods resulted in comparable estimates of oxygen transfer parameters for the aerators under process conditions.展开更多
基金financially supported by the research program of K1-METfinancially supported within the Austrian competence centre program COMET by the Federal Ministry of Economy,Family and Youth+3 种基金by the Federal Ministry for Transport,Innovation and Technologyby the federal states of Upper Austria,Styria,and Tyrolby the Styrian Business Promotion Agencyby the Tiroler Zukunftsstiftung
文摘The residue from a second-stage dry sinter plant off-gas cleaning process contains both the fine dust from the sinter plant and the sorbent used. Recycling of the material that is usually handled by landfills to the sinter plant feed is not possible because of its chloride con- tent. Leaching of the chlorides allow the recycling of remaining solids. The saline leachate produced contains some heavy metals and must be treated before it is discharged into the sea. In laboratory experiments, leaching tests with the subsequent treatment of the leachate were con- ducted. After the process was optimized, all heavy-metal concentrations were below the permissible values. The optimum treatment condi- tions for heavy-metal precipitation were observed to be the filtration of the suspended solids followed by the dosing of liquid with lime milk （pH 10） and the subsequent precipitation using sodium sulfide.
文摘The first imported off-gas analysis system on 150 t BOF at Benxi Plates Co.Ltd. is presented and the continuous determination of bath carbon content has been studied. Thecomparison between the whole-course carbon integral model and the end-point carbon prediction modelhas been made. The results show that the regular change of CO, CO_2 and N_2 content in the off-gasduring blowing plays an important role in judging the smelting end-point of converter; the cubiccurve fitting model has a higher hit rate over 95 percent for the heats whose end-point carboncontent is lower than 0.10 percent with a precision of +-0.02 percent and has a large error for theheats whose end-point carbon content is more than 0.15 percent.
文摘In copper sulfide concentrates smelting, the off-gases from the Pierce Smith converter (PSC) furnace must be treated to prevent environmental impacts as they are highly corrosive and toxic. The purpose of this research project is to present a methodology for the simulation of a capture and cooling system of the smelting off-gases from a Pierce Smith copper converter, using computational fluid dynamics. Through this methodology, it is possible to obtain a simulation model of the smelting off-gases behavior with an average error of 9.88%. Basically, it demonstrates that the simulated tendencies of the metallurgical off-gases on the cooling hood and chamber can be reliable to predict the thermo-fluid dynamic behavior of the off-gases inside the studied off-gases handling system.
文摘Looking back at over a decade of research by herself and her group,the author advocates the added value of gas phase measurements and the application of mass balances,as well as the synergetic benefits obtained when combining both.The increased application of off-gas measurements for greenhouse gas emission monitoring offers a great opportunity to look at other components in the gas phase,particularly oxygen.Mass balances should not be strictly reserved for modellers but also prove useful while conducting lab experiments and studying full-scale measurement data.Combining off-gas measurements with mass balances may serve not only to quantify greenhouse gas emission factors and aeration efficiency but also to follow dynamic concentration profiles of dissolved components without dedicated sensors and/or to calculate other unmeasured variables.Mass-balance-based data reconciliation allows for obtaining reliable and accurate data,and even more when combined with off-gas analysis.
文摘The biofilter is cost-effective for the waste gases treatment. The bacterial is the main microorganism in the conventional biofilters. However, it faces some problems on the elimination of hydrophobic compounds. In order to overcome these problems, the biofilters with fungi were developed. The objective of this study is to investigate the factors affecting ethyl mercaptan(EM)-degradation using a fungal biofilter. A laboratory experiment was set up. The effects of loading rate, empty bed residence times(EBRT) and pH on EM degradation were investigated. Over 95% removals of EM could be achieved, under the condition of the influent loadings below 50 g/(m·h). Removal efficiencies improved to 98% with EM loading decreased to 45 g/(m·h). For long EBRT of 58 s corresponding to a flow rate of 0.3 m3/h, the EM removal efficiencies of over 98% were observed. However, when EBRT was decreased to 14 s, the removal efficiencies fell under 80%. The pH range of 3—5 was feasible to fungi.
基金financial support from the National Natural Science Foundation of China (51706149, 51709191, 51606130)the China Postdoctoral Science Foundation (2018M643474)。
文摘In the present study, a bubble generator and a bubble separator were designed and evaluated for an independent off-gas removal system of a small thorium molten salt reactor(TMSR) with reference to the design of the Oak Ridge National Laboratory(ONRL). The bubble generator employed a Venturi tube as its main body owing to its simplicity and highly reliable structure. A centrifugal separator was used as the bubble separator, taking advantage of the kinetic energy of fluid to create a centrifugal force to separate gas bubbles from the mixture flow. Both the bubble generator and the separator were demonstrated to have good potential to meet the performance requirements of an off-gas removal system for a small TMSR. With water and air as the working fluids, for the final designs of the two key pieces of equipment, a liquid flow rate exceeding 15 m3·h-1 can essentially make their performance meet the requirements of the off-gas removal system in terms of the average size of the generated bubbles and gas separation efficiency.
基金financially supported by the National Natural Science Foundation of China(Nos.51478456 and 51308527)
文摘Sulfur dioxide（SO_2） and benzene homologs are frequently present in the off-gas during the process of sewage sludge drying. A laboratory scale biofilter was set up to co-treat SO_2 and o-xylene in the present study. SO_2 and o-xylene could be removed simultaneously in a single biofilter. Their concentration ratio in the inlet stream influenced the removal efficiencies. It is worth noting that the removal of SO_2 could be enhanced when low concentrations of o-xylene were introduced into the biofilter. Pseudomonas sp., Paenibacillus sp., and Bacillus sp. were the main functional bacteria groups in the biofilter. Sulfur-oxidizing bacteria（SOB） and o-xylene-degrading bacteria（XB） thrived in the biofilter and their counts as well as their growth rate increased with the increase in amount of SO2 and o-xylene supplied. The microbial populations differed in counts and species due to the properties and components of the compounds being treated in the biofilter. The presence of mixed substrates enhanced the diversity of the microbial population. During the treatment process, bioaerosols including potentially pathogenic bacteria, e.g., Acinetobacter lwoffii and Aeromonas sp., were emitted from the biofilter. Further investigation is needed to focus on the potential hazards caused by the bioaerosols emitted from waste gas treatment bioreactors.
基金supported by the National Natural Science Foundations of China(21966002 and 21871047)the Natural Science Foundation of Jiangxi Province(20181ACB20003)+1 种基金the Training Program for Academic and Technical Leaders of Major Disciplines in Jiangxi Province(20194BCJ22010)the Graduate Innovation Project of East China University of Technology(DHYC-202023)。
文摘Direct separation of Xe and Kr from air or used nuclear fuel(UNF)off-gas by means of porous adsorbents is of industrial importance but is a very challenging task.In this work,we show a robust metal-organic framework(MOF),namely ECUT-60,which renders not only high chemical stability,but also unique structure with multiple traps.This leads to the ultrahigh Xe adsorption capacity,exceeding most reported porous materials.Impressively,this MOF also enables high selectivity of Xe over Kr,CO2,O2,and N2,leading to the high-performance separation for trace quantitites of Xe/Kr from a simulated UNF reprocessing off-gas.The separation capability has been demonstrated by using dynamic breakthrough experiments,giving the record Xe uptake up to 70.4 mmol/kg and the production of 19.7 mmol/kg pure Xe.Consequently,ECUT-60 has promising potential in direct production of Xe from UNF off-gas or air.The separation mechanism,as unveiled by theoretical calculation,is attributed to the multiple traps in ECUT-60 that affords rigid restrict for Xe atom via van der Waals force.
基金supported by the National Natural Science Foundation of China (No. 50921064)
文摘We investigated the correlation between performance and the bacteria community composition by H2S and toluene co-treatment. Operation of the bioreactor was divided into four stages, in which the inlet concentration of toluene and H2S were gradually increased. In Stage I, toluene was the sole target compound with an average removal efficiency of 86.49%. After adding HeS in Stage II, removal efficiency of toluene decreased immediately and recovered gradually to 85.96%. When the inlet concentration of toluene and HzS was increased in Stage III and Stage IV, respectively, the average removal efficiency for toluene increased continuously from 86.31% to 87.24%. The elimination capacities of toluene increased with increasing inlet loading rates of toluene and H2S. Results of the PCR-DGGE analysis showed a turnover growth and decline of the microbial populations in the bioreactor. In Stage I, the dominant toluene-degrading bacteria mainly contained Pseudomonas sp. strain PS ＋ and Hydrogenophaga sp. In Stage IV, however, the dominant toluene-degrading bacteria was aciduric bacteria （Clostridium populeti）. The dominant microbial community in the bioreactor enhanced the elimination capacity of toluene, and adding H2S changed the environment of microbial growth, thus resulted in an evolution of dominant microorganisms. Analyses of microbial community and their activities provides valuable information to efficiently enhance simultaneous removal of toluene and H2S in the bioreactor.
基金Sponsored by Science and Technology Plan Projects of Tianjin of China(07ZCKFGX03800)Science and Technology Plan Projects for CAS Supporting Tianjin Construction of China(TJZX1-YW-09)
文摘Converter off-gas, an important energy resource for steel industries, is one of the weak points in the recov ery and utilization of secondary energy resources. To improve the level of recycling converter off-gas in steel plants, a novel approach to the recycle of CO2 separated from converter off-gas or other off-gas for the green slag splashing technique was developed, and the CO2 equilibrium conversion ratio of the green CO2 slag splashing under different technological conditions was calculated by the program of enthalpy （H）, entropy （S）, and heat capacity （C）, i.e. HSC software. Furthermore, the experiments of CO2 injected into molten converter slag were carried out, and the influencing factors of the green slag splashing technique using CO2 were analyzed. The experimental results showed that the carbon content for smooth slag splashing using COs was about 4.0%.
基金supported by the Major Water Project of the National Science and Technology (No.2011ZX07319-001-004, 2011ZX07301-002)
文摘Knowledge of the oxygen mass transfer of aerators under operational conditions in a full-scale wastewater treatment plant （WWTP） is meaningful for the optimization of WWTP, however, scarce to best of our knowledge. Through analyzing a plug flow aeration tank in the Lucun WWTP, in Wuxi, China, the oxygenation capacity of fine-bubble aerators under process conditions have been measured in- situ using the off-gas method and the non-steady-state method. The off-gas method demonstrated that the aerators in different corridors in the aeration tank of WWTP had significantly different oxygen transfer performance; furthermore, the aerators in the same corridor shared almost equal oxygen transfer performance over the course of a day. Results measured by the two methods showed that the oxygen transfer performance of fine-bubble aerators in the aeration tank decreased dramatically compared with that in the clean water. The loss of oxygen transfer coefficient was over 50% under low-aeration conditions （aeration amount 〈 0.67 Nm 3 /hr）. However, as the aeration amount reached 0.96 Nm 3 /hr, the discrepancy of oxygen transfer between the process condition and clean water was negligible. The analysis also indicated that the non-steady-state and off-gas methods resulted in comparable estimates of oxygen transfer parameters for the aerators under process conditions.
