“…When the belt was empty or if there was not enough pulverized coal to be analyzed, distance values were about 95 mm, so the XRF analyzer was interrupted (off). After pulverized coal was smoothed by the sled, the distance values were almost entirely in the range of 81.1-81.6 mm due to the machinery vibration of conveyor belt and rough surface textures of pulverized coal, then the XRF analyzer would continuously measure online for 100 s. In the previous study, Ge et al 25 found that the accuracy of measurement can be accepted when the distance changed within 0.5 mm; the intensity-distance correction method 15 was used hardly at all.…”
Section: Resultsmentioning
confidence: 99%
“…After pulverized coal was smoothed by the sled, the distance values were almost entirely in the range of 81.1–81.6 mm due to the machinery vibration of conveyor belt and rough surface textures of pulverized coal, then the XRF analyzer would continuously measure online for 100 s. In the previous study, Ge et al. 25 found that the accuracy of measurement can be accepted when the distance changed within 0.5 mm; the intensity–distance correction method 15 was used hardly at all. Figure 4.Typical measuring distance results by laser rangefinder.…”
Section: Resultsmentioning
confidence: 99%
“…However, once the distance changes go beyond the range by some unexpected things at any time, the distance correction method 15 will be used to increase the accuracy of measurement. For example, if the average distance is 83 mm (beyond the range), the measured fluorescent intensity ( I m ) can be corrected by: 15 where I m is the value of the measured fluorescent intensity, I n is the corrected value of I m , D 0 is the default distance between the X-ray beam points on the sample surface and the instrument, D m is the average value of the actually measured distance, a is the correction factor which was obtained by experimental measurement. I n can be substituted in the calibration curve in Fig.…”
Section: Resultsmentioning
confidence: 99%
“…Recently, XRF instrumentation has been proven to be successful for monitoring copper, arsenic, sulfur, 13 and chrome-iron ores. 14 In our previous study, 15 an XRF analysis system mounted on a stationary sample platform had been developed for sulfur determination, indicating that using a new distance correction method had made some significant improvement in measurement accuracy of sulfur concentration.…”
Section: Introductionmentioning
confidence: 99%
“…20 And in the work by Croudace et al., 21 the sample-detector distance was kept constant by continuously moving the detector and they achieves this by using a laser triangulation system to measure the topography of the sample surface. However, in our online XRF analyzer, the detector was settled, so a distance correction method 15 was used to weaken the impact of rough and uneven surface of the pulverized coal to the measurement accuracy of heavy metal. Figure 1.Online XRF analysis system during the fuel supply process.…”
Heavy metals in haze episode will continue to threaten the quality of public health around the world. In order to decrease the emission of heavy metals produced from coal burning, an online X-ray fluorescence (XRF) analyzer system, consisting of an XRF analyzer with data acquisition software and a laser rangefinder, was developed to carry out the measurement of heavy metals in pulverized coal. The XRF analyzer was mounted on a sled, which can effectively smooth the surface of pulverized coal and reduce the impact of surface roughness during online measurement. The laser rangefinder was mounted over the sled for measuring the distance between a pulverized coal sample and the analyzer. Several heavy metals and other elements in pulverized coal were online measured by the XRF analyzer directly above a conveyor belt. The limits of detection for Hg, Pb, Cr, Ti, Fe, and Ca by the analyzer were 44 ± 2, 34 ± 2, 17 ± 3, 41 ± 4, 19 ± 3, and 65 ± 2 mg·kg(-1), respectively. The relative standard deviation (%RSD) for the elements mentioned was less than 7.74%. By comparison with the results by inductively-coupled plasma mass spectrometry (ICP-MS), relative deviation (%D) of the online XRF analyzer was less than 10% for Cr, Ti, and Ca, in the range of 0.8-24.26% for Fe, and greater than 20% for Hg and Pb.
“…When the belt was empty or if there was not enough pulverized coal to be analyzed, distance values were about 95 mm, so the XRF analyzer was interrupted (off). After pulverized coal was smoothed by the sled, the distance values were almost entirely in the range of 81.1-81.6 mm due to the machinery vibration of conveyor belt and rough surface textures of pulverized coal, then the XRF analyzer would continuously measure online for 100 s. In the previous study, Ge et al 25 found that the accuracy of measurement can be accepted when the distance changed within 0.5 mm; the intensity-distance correction method 15 was used hardly at all.…”
Section: Resultsmentioning
confidence: 99%
“…After pulverized coal was smoothed by the sled, the distance values were almost entirely in the range of 81.1–81.6 mm due to the machinery vibration of conveyor belt and rough surface textures of pulverized coal, then the XRF analyzer would continuously measure online for 100 s. In the previous study, Ge et al. 25 found that the accuracy of measurement can be accepted when the distance changed within 0.5 mm; the intensity–distance correction method 15 was used hardly at all. Figure 4.Typical measuring distance results by laser rangefinder.…”
Section: Resultsmentioning
confidence: 99%
“…However, once the distance changes go beyond the range by some unexpected things at any time, the distance correction method 15 will be used to increase the accuracy of measurement. For example, if the average distance is 83 mm (beyond the range), the measured fluorescent intensity ( I m ) can be corrected by: 15 where I m is the value of the measured fluorescent intensity, I n is the corrected value of I m , D 0 is the default distance between the X-ray beam points on the sample surface and the instrument, D m is the average value of the actually measured distance, a is the correction factor which was obtained by experimental measurement. I n can be substituted in the calibration curve in Fig.…”
Section: Resultsmentioning
confidence: 99%
“…Recently, XRF instrumentation has been proven to be successful for monitoring copper, arsenic, sulfur, 13 and chrome-iron ores. 14 In our previous study, 15 an XRF analysis system mounted on a stationary sample platform had been developed for sulfur determination, indicating that using a new distance correction method had made some significant improvement in measurement accuracy of sulfur concentration.…”
Section: Introductionmentioning
confidence: 99%
“…20 And in the work by Croudace et al., 21 the sample-detector distance was kept constant by continuously moving the detector and they achieves this by using a laser triangulation system to measure the topography of the sample surface. However, in our online XRF analyzer, the detector was settled, so a distance correction method 15 was used to weaken the impact of rough and uneven surface of the pulverized coal to the measurement accuracy of heavy metal. Figure 1.Online XRF analysis system during the fuel supply process.…”
Heavy metals in haze episode will continue to threaten the quality of public health around the world. In order to decrease the emission of heavy metals produced from coal burning, an online X-ray fluorescence (XRF) analyzer system, consisting of an XRF analyzer with data acquisition software and a laser rangefinder, was developed to carry out the measurement of heavy metals in pulverized coal. The XRF analyzer was mounted on a sled, which can effectively smooth the surface of pulverized coal and reduce the impact of surface roughness during online measurement. The laser rangefinder was mounted over the sled for measuring the distance between a pulverized coal sample and the analyzer. Several heavy metals and other elements in pulverized coal were online measured by the XRF analyzer directly above a conveyor belt. The limits of detection for Hg, Pb, Cr, Ti, Fe, and Ca by the analyzer were 44 ± 2, 34 ± 2, 17 ± 3, 41 ± 4, 19 ± 3, and 65 ± 2 mg·kg(-1), respectively. The relative standard deviation (%RSD) for the elements mentioned was less than 7.74%. By comparison with the results by inductively-coupled plasma mass spectrometry (ICP-MS), relative deviation (%D) of the online XRF analyzer was less than 10% for Cr, Ti, and Ca, in the range of 0.8-24.26% for Fe, and greater than 20% for Hg and Pb.
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