The GC determination of aldehydes and ketones in stack gas was reported. The stack gas was collected with the dust sampler by isokinetic sampling technique, 2,4 dinitrophenylhydrazine in acidic solution was used to a...The GC determination of aldehydes and ketones in stack gas was reported. The stack gas was collected with the dust sampler by isokinetic sampling technique, 2,4 dinitrophenylhydrazine in acidic solution was used to absorb aldehydes and ketones in stack gas specifically, to form their hydrazones, which were determined by GC with a capillary column of SE 54. The GC system can separate nine hydrazones of carbonyls interested with constant recovery rates of 94%—97%, giving lowest detectable limits of 0 05—1 0 ng. The standard gas of carbonyls were determined by this method with relative errors of -5% to -10%, percent coefficients of variation within 5%, and spiking recovery rates of 93%—97%. As an application of the method, the carbonyl pollutants were determined in stack gas samples of a chemical plant.展开更多
Based on the analysis of spectrum characteristics of intensity fluctuations while light beams pass through stack gas flow in an industrial setting, this paper puts emphasis upon discussing the spectrum of optical inte...Based on the analysis of spectrum characteristics of intensity fluctuations while light beams pass through stack gas flow in an industrial setting, this paper puts emphasis upon discussing the spectrum of optical intensity fluctuations by the variety of particle concentration in stack gas flow. This paper also gives the primary theoretical explanation of the measurement results in the stack of coal-fired utility boilers. Meanwhile, the cross-correlation formula is given as the theoretical basis of velocity measurement by using particle concentration scintillation.展开更多
For acid pickling heat treated mild steel and steel products, up to the middle of the last century, sulfuric acid was primarily in use, which has been replaced stepwise by hydrochloric acid since the sixties. During t...For acid pickling heat treated mild steel and steel products, up to the middle of the last century, sulfuric acid was primarily in use, which has been replaced stepwise by hydrochloric acid since the sixties. During this time, the pickling of high alloyed steel with hydrofluoric acid or mixtures for hydrofluoric acid together with nitric acid has also been applied on industrial scale. The technologies used by several plant contractors hereby show considerable differences in their engineering. The study provides a survey of the progress in the state of art of regeneration technology as well as the use of different pickl.ing media in the form of a review on existing technologies as well as improvements done within the recent years in the area.展开更多
The impact of a typical municipal solid waste incinerator （MSWI） on polychlorinated biphenyl （PCB） concentrations in the surrounding soil was studied. Six stack gas samples were taken from the MSWI and 21 soil sam...The impact of a typical municipal solid waste incinerator （MSWI） on polychlorinated biphenyl （PCB） concentrations in the surrounding soil was studied. Six stack gas samples were taken from the MSWI and 21 soil samples were collected from sampling sites between 300 and 1700 m from the MSWI stack. The total （∑PCB） concentrations of dioxin-like （dl） PCBs and indicator PCBs in the stack gas samples were between 3.41 and 34.3 ng/m3, and the corresponding toxic equivalents （TEQs） ranged from 4.45 to 66.9 pg WHO-TEQ/m3, with a mean of 28.6 pg WHO-TEQ/m3. A total of 2.43 g WHO-TEQ of PCBs per year was calculated to be released into the environment from MSWIs in China. The ∑PCB concentrations in the soil samples ranged from 28.0 to 264.4 pg/g, with mean and median values of 127.6 and 127.7 pg/g, respectively, while the TEQ values were between 0.020 and 0.18 pg WHO-TEQ/g, with mean and median values of 0.074 and 0.062 pg WHO-TEQ/g, respectively. Comparing this study with other studies performed around the world suggest that PCB emission from incinerators has a critical influence on PCB concentrations in the surrounding soil. An exponential function equation is proposed, which indicates a clear decline in ∑PCB concentrations with increasing distance from the stack. A contour map created using an ordinary kriging interpolation technique showed that a limited area （1250 m radius） from the stack was clearly influenced by PCB emission from the MSWI.展开更多
The proportion of steel produced using electric arc furnaces(EAFs)is increasing.In this study,polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)concentrations and patterns in stack gas samples from three typ...The proportion of steel produced using electric arc furnaces(EAFs)is increasing.In this study,polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)concentrations and patterns in stack gas samples from three typical EAFs in steelmaking plants were determined to allow the contributions of EAFs in steelmaking plants to PCDD/Fs emissions in China to be assessed.Samples collection was accomplished by adopting the automatic isokinetic sampling technique,then the PCDD/Fs congeners concentrations were analyzed qualitatively and quantitatively by isotope dilution high-resolution gas chromatography high-resolution mass spectrometry(HRGC-HRMS).The mean PCDD/Fs mass concentrations in stack gases emitted during the scrap preheating phase of plants E1,E2,and E3 were 0.48,385.55,and 0.34 ng Nm^-3,respectively,and the total toxic equivalent(WHO2005-TEQ)concentrations were 0.05,33.16,and 0.03 ng Nm^-3,respectively.The PCDD/Fs mass concentration in stack gases emitted during the melting phase at plant E3 was 0.12 ng Nm^-3(0.02 ng WHO2005-TEQ Nm^-3).The operational temperature of the bag filter of the preheating in the E2 EAF was as high as 230℃,which is conducive to the generation of PCDD/Fs,whether the temperature in the bag filter of E1(150℃)and E3(120℃)are not.Moreover,the bag filter temperature is suggested to be best controlled to below 150℃.The emission factors(EF)for PCDD/Fs released into the air during the scrap preheating phase for plants E1,E2,and E3 were 0.13,52,and 0.10 mg WHO2005-TEQ t1,respectively,and the EF for the smelting phase from plant E3 was 0.14 mg WHO2005-TEQ t1.The emission factor in E2 is 5 times higher than the highest current UNEP toolkit factor for EAFs(10 mg TEQ/tonne steel).Therefore,an update for the UNEP toolkit emission factor for a few case plants is suggested.Several congeners,including 2,3,7,8-TeCDF,1,2,3,4,6,7,8-HpCDF,and 1,2,3,4,6,7,8-HpCDD,were dominant during the preheating phase,while 2,3,7,8-TeCDF,1,2,3,7,8-PeCDF,and 2,3,4,7,8-PeCDF were dominant during the smelting phase.The monitoring data from the case plants helps to better understand the PCDD/Fs emissions of EAFs using preheating process stages.However,a more complete emission inventory requires more case investigations on the PCDD/Fs emissions from representative EAFs steelmaking plants.展开更多
This study set out to assess the characteristics of polycyclic aromatic hydrocarbon （PAH） emission from coking industries, with field samplings conducted at four typical coke plants. For each selected plant, stack f...This study set out to assess the characteristics of polycyclic aromatic hydrocarbon （PAH） emission from coking industries, with field samplings conducted at four typical coke plants. For each selected plant, stack flue gas samples were collected during processes that included charging coal into the ovens （CC）, pushing coke （PC） and the combustion of coke-oven gas （CG）. Sixteen individual PAHs on the US EPA priority list were analyzed by gas chromatography/mass spectrometry （GC/MS）. Results showed that the total PAH concentrations in the flue gas ranged from 45.776 to 414.874 μg/m3, with the highest emission level for CC （359.545μg/m3）, The concentration of PAH emitted from the CC process in CP1 （stamp charging） was lower than that from CP3 and CP4 （top charging）. Low-molecular-weight PAHs （i.e., two- to three-ring PAHs） were predominant contributors to the total PAH contents, and Nap, AcPy, Flu, PhA, and AnT were found to be the most abundant ones. Total BaPeq concentrations for CC （2.248 μg/m3） were higher than those for PC （ 1.838 μg/m3 ） and CG （1.082 μg/m3 ）, and DbA was an important contributor to carcinogenic risk as BaP in emissions from coking processes. Particulate PAH accounted for more than 20% of the total BaPeq concentrations, which were significantly higher than the corresponding contributions to the total PAH mass concentration （5%）. Both particulate and gaseous PAH should be taken into consideration when the potential toxicity risk of PAH pollution during coking processes is assessed. The mean total-PAH emission factors were 346.132 and 93.173μg/kg for CC and PC, respectively.展开更多
文摘The GC determination of aldehydes and ketones in stack gas was reported. The stack gas was collected with the dust sampler by isokinetic sampling technique, 2,4 dinitrophenylhydrazine in acidic solution was used to absorb aldehydes and ketones in stack gas specifically, to form their hydrazones, which were determined by GC with a capillary column of SE 54. The GC system can separate nine hydrazones of carbonyls interested with constant recovery rates of 94%—97%, giving lowest detectable limits of 0 05—1 0 ng. The standard gas of carbonyls were determined by this method with relative errors of -5% to -10%, percent coefficients of variation within 5%, and spiking recovery rates of 93%—97%. As an application of the method, the carbonyl pollutants were determined in stack gas samples of a chemical plant.
文摘Based on the analysis of spectrum characteristics of intensity fluctuations while light beams pass through stack gas flow in an industrial setting, this paper puts emphasis upon discussing the spectrum of optical intensity fluctuations by the variety of particle concentration in stack gas flow. This paper also gives the primary theoretical explanation of the measurement results in the stack of coal-fired utility boilers. Meanwhile, the cross-correlation formula is given as the theoretical basis of velocity measurement by using particle concentration scintillation.
文摘For acid pickling heat treated mild steel and steel products, up to the middle of the last century, sulfuric acid was primarily in use, which has been replaced stepwise by hydrochloric acid since the sixties. During this time, the pickling of high alloyed steel with hydrofluoric acid or mixtures for hydrofluoric acid together with nitric acid has also been applied on industrial scale. The technologies used by several plant contractors hereby show considerable differences in their engineering. The study provides a survey of the progress in the state of art of regeneration technology as well as the use of different pickl.ing media in the form of a review on existing technologies as well as improvements done within the recent years in the area.
基金supported by the National Program on Key Basic Research Project (973) of China (No.2011CB201500)the Environmental Public Welfare Projects (No.201209019, 201109001)+1 种基金the National Hightech Research and Development Program (863) of China (No.2011AA060605)the National Natural Science Foundation of China (No.20977099, 21077121)
文摘The impact of a typical municipal solid waste incinerator （MSWI） on polychlorinated biphenyl （PCB） concentrations in the surrounding soil was studied. Six stack gas samples were taken from the MSWI and 21 soil samples were collected from sampling sites between 300 and 1700 m from the MSWI stack. The total （∑PCB） concentrations of dioxin-like （dl） PCBs and indicator PCBs in the stack gas samples were between 3.41 and 34.3 ng/m3, and the corresponding toxic equivalents （TEQs） ranged from 4.45 to 66.9 pg WHO-TEQ/m3, with a mean of 28.6 pg WHO-TEQ/m3. A total of 2.43 g WHO-TEQ of PCBs per year was calculated to be released into the environment from MSWIs in China. The ∑PCB concentrations in the soil samples ranged from 28.0 to 264.4 pg/g, with mean and median values of 127.6 and 127.7 pg/g, respectively, while the TEQ values were between 0.020 and 0.18 pg WHO-TEQ/g, with mean and median values of 0.074 and 0.062 pg WHO-TEQ/g, respectively. Comparing this study with other studies performed around the world suggest that PCB emission from incinerators has a critical influence on PCB concentrations in the surrounding soil. An exponential function equation is proposed, which indicates a clear decline in ∑PCB concentrations with increasing distance from the stack. A contour map created using an ordinary kriging interpolation technique showed that a limited area （1250 m radius） from the stack was clearly influenced by PCB emission from the MSWI.
基金the National Natural Science Foundation of China(grant nos.21936007 and 21906165)the CAS Interdisciplinary Innovation Team(grant no.JCTD-2019-03)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(grant no.2016038).
文摘The proportion of steel produced using electric arc furnaces(EAFs)is increasing.In this study,polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)concentrations and patterns in stack gas samples from three typical EAFs in steelmaking plants were determined to allow the contributions of EAFs in steelmaking plants to PCDD/Fs emissions in China to be assessed.Samples collection was accomplished by adopting the automatic isokinetic sampling technique,then the PCDD/Fs congeners concentrations were analyzed qualitatively and quantitatively by isotope dilution high-resolution gas chromatography high-resolution mass spectrometry(HRGC-HRMS).The mean PCDD/Fs mass concentrations in stack gases emitted during the scrap preheating phase of plants E1,E2,and E3 were 0.48,385.55,and 0.34 ng Nm^-3,respectively,and the total toxic equivalent(WHO2005-TEQ)concentrations were 0.05,33.16,and 0.03 ng Nm^-3,respectively.The PCDD/Fs mass concentration in stack gases emitted during the melting phase at plant E3 was 0.12 ng Nm^-3(0.02 ng WHO2005-TEQ Nm^-3).The operational temperature of the bag filter of the preheating in the E2 EAF was as high as 230℃,which is conducive to the generation of PCDD/Fs,whether the temperature in the bag filter of E1(150℃)and E3(120℃)are not.Moreover,the bag filter temperature is suggested to be best controlled to below 150℃.The emission factors(EF)for PCDD/Fs released into the air during the scrap preheating phase for plants E1,E2,and E3 were 0.13,52,and 0.10 mg WHO2005-TEQ t1,respectively,and the EF for the smelting phase from plant E3 was 0.14 mg WHO2005-TEQ t1.The emission factor in E2 is 5 times higher than the highest current UNEP toolkit factor for EAFs(10 mg TEQ/tonne steel).Therefore,an update for the UNEP toolkit emission factor for a few case plants is suggested.Several congeners,including 2,3,7,8-TeCDF,1,2,3,4,6,7,8-HpCDF,and 1,2,3,4,6,7,8-HpCDD,were dominant during the preheating phase,while 2,3,7,8-TeCDF,1,2,3,7,8-PeCDF,and 2,3,4,7,8-PeCDF were dominant during the smelting phase.The monitoring data from the case plants helps to better understand the PCDD/Fs emissions of EAFs using preheating process stages.However,a more complete emission inventory requires more case investigations on the PCDD/Fs emissions from representative EAFs steelmaking plants.
基金supported jointly by the R&D Special Fund for Public Welfare Industry of China(200809027)the National Natural Science Foundation of China(NSFC)(No. 41173002)
文摘This study set out to assess the characteristics of polycyclic aromatic hydrocarbon （PAH） emission from coking industries, with field samplings conducted at four typical coke plants. For each selected plant, stack flue gas samples were collected during processes that included charging coal into the ovens （CC）, pushing coke （PC） and the combustion of coke-oven gas （CG）. Sixteen individual PAHs on the US EPA priority list were analyzed by gas chromatography/mass spectrometry （GC/MS）. Results showed that the total PAH concentrations in the flue gas ranged from 45.776 to 414.874 μg/m3, with the highest emission level for CC （359.545μg/m3）, The concentration of PAH emitted from the CC process in CP1 （stamp charging） was lower than that from CP3 and CP4 （top charging）. Low-molecular-weight PAHs （i.e., two- to three-ring PAHs） were predominant contributors to the total PAH contents, and Nap, AcPy, Flu, PhA, and AnT were found to be the most abundant ones. Total BaPeq concentrations for CC （2.248 μg/m3） were higher than those for PC （ 1.838 μg/m3 ） and CG （1.082 μg/m3 ）, and DbA was an important contributor to carcinogenic risk as BaP in emissions from coking processes. Particulate PAH accounted for more than 20% of the total BaPeq concentrations, which were significantly higher than the corresponding contributions to the total PAH mass concentration （5%）. Both particulate and gaseous PAH should be taken into consideration when the potential toxicity risk of PAH pollution during coking processes is assessed. The mean total-PAH emission factors were 346.132 and 93.173μg/kg for CC and PC, respectively.
