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.T展开更多
After comparing the mechanism of tilted plume under stack effect with that of spill plume,the tilted plume model induced by stack effect in a vertical shaft is developed simply based on the theoretical results and a s...After comparing the mechanism of tilted plume under stack effect with that of spill plume,the tilted plume model induced by stack effect in a vertical shaft is developed simply based on the theoretical results and a series of full-scale tests. It is shown that the two sides of plume are symmetrical and have an accordant regulation that the plume radius has a linear relation to the height z. The profile of fire plume under stack effect is similar to the windblown flame in wind tunnel,and the range of flame deflection angle is about from 50 to 60 degree.展开更多
The deep seismic reflection profiling carried out in Xingtai earthquake area provides a new knowledge of the crustal structure of the Shulu fault basin and its vicinity. In the Ningjin-Xinhe and Lincheng-Julu deep sei...The deep seismic reflection profiling carried out in Xingtai earthquake area provides a new knowledge of the crustal structure of the Shulu fault basin and its vicinity. In the Ningjin-Xinhe and Lincheng-Julu deep seismic reflection profiles trending in NWW, CDP stack profiles respectively show a one-side fault basin (i. e. Shulu fault basin) within TWT 4. 0s. The width of the basin is about 15 km (Eogene system boundary), and Xinhe fault extends to below TWT 4. 0s (i. e. 8 km deep) with listric shape as a main boundary fault. These profiles also display distinctly a detachment in mid-crust. The Xinhe fault extends downward and converges to the detachment. The results of deep seismic sounding and magnetotelluric sounding indicate the low-velocity and highconductive zone beneath the detachment, which is beneficial to the detach between upper and lower plates. The Renxian-Ningjin deep seismic reflection profile trending in NNE lies within the fault basin, which shows the complicated structure of the basin. The shallow part of the profile is divided into three sub-basins by three lateral uplifts. In the mid-lower crust from Gengzhuangqiao to Xiaohezhuang of the profile, there are a lot of strong reflection events with laminae structure, which have been deformed strongly. Two NWW-trending profiles also have similar reflection feature. This may indicate that there is a relative large region where the magma upwell into mid-lower crust. The abnormal low velocity zone in lower crust indicates that the magmatism is still strong at present. The magmatism may be an important factor of the tectonic active region.展开更多
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.T
基金supported by the National Key Project of Scientific and Technical Supporting Programs Funded by Ministry of Science &Technology of China ( Grant No: 2006BAJ13B03)the RGCCERG Grant #CityU1253/04E from Hong Kong Re-search Grant Council, HKSAR
文摘After comparing the mechanism of tilted plume under stack effect with that of spill plume,the tilted plume model induced by stack effect in a vertical shaft is developed simply based on the theoretical results and a series of full-scale tests. It is shown that the two sides of plume are symmetrical and have an accordant regulation that the plume radius has a linear relation to the height z. The profile of fire plume under stack effect is similar to the windblown flame in wind tunnel,and the range of flame deflection angle is about from 50 to 60 degree.
文摘The deep seismic reflection profiling carried out in Xingtai earthquake area provides a new knowledge of the crustal structure of the Shulu fault basin and its vicinity. In the Ningjin-Xinhe and Lincheng-Julu deep seismic reflection profiles trending in NWW, CDP stack profiles respectively show a one-side fault basin (i. e. Shulu fault basin) within TWT 4. 0s. The width of the basin is about 15 km (Eogene system boundary), and Xinhe fault extends to below TWT 4. 0s (i. e. 8 km deep) with listric shape as a main boundary fault. These profiles also display distinctly a detachment in mid-crust. The Xinhe fault extends downward and converges to the detachment. The results of deep seismic sounding and magnetotelluric sounding indicate the low-velocity and highconductive zone beneath the detachment, which is beneficial to the detach between upper and lower plates. The Renxian-Ningjin deep seismic reflection profile trending in NNE lies within the fault basin, which shows the complicated structure of the basin. The shallow part of the profile is divided into three sub-basins by three lateral uplifts. In the mid-lower crust from Gengzhuangqiao to Xiaohezhuang of the profile, there are a lot of strong reflection events with laminae structure, which have been deformed strongly. Two NWW-trending profiles also have similar reflection feature. This may indicate that there is a relative large region where the magma upwell into mid-lower crust. The abnormal low velocity zone in lower crust indicates that the magmatism is still strong at present. The magmatism may be an important factor of the tectonic active region.
