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Rodney Bryant Olatunde Sanni Elizabeth Moore Matthew Bundy Aaron Johnson 《Journal of the Air & Waste Management Association (1995)》2014,64(6):679-689
Point velocity measurements conducted by traversing a Pitot tube across the cross section of a flow conduit continue to be the standard practice for evaluating the accuracy of continuous flow-monitoring devices. Such velocity traverses were conducted in the exhaust duct of a reduced-scale analog of a stationary source, and mean flow velocity was computed using several common integration techniques. Sources of random and systematic measurement uncertainty were identified and applied in the uncertainty analysis. When applicable, the minimum requirements of the standard test methods were used to estimate measurement uncertainty due to random sources. Estimates of the systematic measurement uncertainty due to discretized measurements of the asymmetric flow field were determined by simulating point velocity traverse measurements in a flow distribution generated using computational fluid dynamics. For the evaluated flow system, estimates of relative expanded uncertainty for the mean flow velocity ranged from ±1.4% to ±9.3% and depended on the number of measurement locations and the method of integration.
Implications:Accurate flow measurements in smokestacks are critical for quantifying the levels of greenhouse gas emissions from fossil-fuel-burning power plants, the largest emitters of carbon dioxide. A systematic uncertainty analysis is necessary to evaluate the accuracy of these measurements. This study demonstrates such an analysis and its application to identify specific measurement components and procedures needing focused attention to improve the accuracy of mean flow velocity measurements in smokestacks. 相似文献
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Sanni Eloneva Pekka Mannisto Arshe Said Carl‐Johan Fogelholm Ron Zevenhoven 《Greenhouse Gases: Science and Technology》2011,1(4):305-311
A mineral carbonation method based on steelmaking slags and ammonium salt solutions has been found to have economical and CO2 emission reduction potential. Although the aqueous solution of ammonium salt can be recycled, some of the solvent is likely to escape in a form of ammonia vapor within the outgoing gas flow during the carbonation step. In this study, the escape of ammonia vapor was investigated. The loss of NH3 was found to be quite insignificant and in addition, the total solution loss per step was very small. The CO2 content of the ingoing gas flow affected the rate of the CaCO3 precipitation; the smaller the CO2 content, the longer the duration of the carbonation reaction. However, the CO2 content did not seem to have a significant effect on the degree of CaCO3 precipitation, indicating that CO2 capture in a separate process step should not be needed. CaCO3 precipitated in a form of calcite, although two of the precipitates also contained aragonite. Furthermore, the precipitates were found to be of high quality with bright white color, and fine and powdery texture. Nonetheless, in order to obtain high‐quality CaCO3, the precipitate resulting from the carbonation step should be washed with an adequate amount of water. © 2011 Society of Chemical Industry and John Wiley & Sons, Ltd 相似文献
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Sanni Eloneva Eeva-Maija Puheloinen Jaakko Kanerva Ari Ekroos Ron Zevenhoven Carl-Johan Fogelholm 《Journal of Cleaner Production》2010,18(18):1833-1839
The steel industry is characterised by large amounts of CO2 emissions, but there is no easy means to reduce these emissions. One interesting option for the reduction of CO2 emissions could be the utilisation of steelmaking slags for carbon dioxide mineralisation. In this option CO2 is bound with the calcium of the slag material, producing stable carbonate as an end product. The utilisation of steelmaking slags as the raw material for carbon dioxide mineralisation will change the quality of the slags. If, however, this change degrades the slags it could prevent the use of slags in carbon dioxide mineralisation or make it very expensive.The purpose of the research presented here is to evaluate this issue with the help of a case study where the quality of the residual slag from the recently suggested carbonation method was experimentally investigated. The CO2 mineralisation method, based on steelmaking slags and ammonium salt solutions, was found to change the quality of the slags: the calcium content was reduced, the CaO and Ca(OH)2 phases were completely dissolved, and the solubility of the V and Cr increased notably. This residual slag would presumably have to be handled as waste. Currently, the steelmaking slag used in the case study is defined as a by-product, but if it is used for CO2 mineralisation instead of liming its legal status will be re-evaluated. Subsequently, the CO2 mineralisation process could possibly be defined as an end-of-waste procedure. 相似文献
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