The in-situ instrumentation technique for measuring mercury and itsspeciation downstream a utility 100 MW pulverized coal (PC) fired boiler system was developed andconducted by the use of the Ontario hydro method (OHM...The in-situ instrumentation technique for measuring mercury and itsspeciation downstream a utility 100 MW pulverized coal (PC) fired boiler system was developed andconducted by the use of the Ontario hydro method (OHM) consistent with American standard test methodtogether with the semi-continuous emissions monitoring (SCEM) system as well as a mobile laboratoryfor mercury monitoring. The mercury and its speciation concentrations including participate mercuryat three locations of before air preheater, before electrostatic precipitator (ESP) and after ESPwere measured using the OHM and SCEM methods under normal operation conditions of the boiler systemas a result of firing a bituminous coal. The vapor-phase total mercury Hg(VT) concentration declinedwith the decrease of flue gas temperature because of mercury species transformation from oxidizedmercury to particulate mercury as the flue gas moved downstream from the air preheater to the ESPand after the ESP. A good agreement for Hg°, Hg^(2+) and Hg( VT) was obtained between the twomethods in the ash-free area. But in the dense particle-laden flue gas area, there appeared to be abig bias for mercury speciation owing to dust cake formed in the filter of OHM sampling probe. Theparticulateaffinity to the flue gas mercury and the impacts of sampling condition to accuracy ofmeasure were discussed.展开更多
Using the ideal gas state equation, an on-line measuring method for the shell chamber volume is studied in this paper. After analyzing how various measurement parameters affect the measurement accuracy, the system par...Using the ideal gas state equation, an on-line measuring method for the shell chamber volume is studied in this paper. After analyzing how various measurement parameters affect the measurement accuracy, the system parameters are optimized in this method. Because the shape and volume of the tested items are similar, the method of using "tamping" to raise the accuracy and speed of the measurement is put forward. Based on the work above, a prototype of the testing instrument for shell chamber volume was developed, automatically testing and controlling. Compared with the method of "water weight", this method is more accurate, quicker and more automotive, so it is adaptable for the use of on-line detection.展开更多
The intrinsic kinetics of iron oxide reduced by carbon monoxide is evaluated by a method of online measuring concentration of off-gas in an isothermal differential micro-packed bed. Under the condition of getting away...The intrinsic kinetics of iron oxide reduced by carbon monoxide is evaluated by a method of online measuring concentration of off-gas in an isothermal differential micro-packed bed. Under the condition of getting away from the influence of gas diffusion and gas–solid heat transfer and mass transfer, the reaction of Fe2O3 to Fe3O4, Fe3O4 to Fe O and Fe O to Fe in the process of single reaction can be clearly distinguished from each other, and the relevant activation energy is characterized to be 75.4, 74.4, and 84.0 k J·mol-1, respectively. Therefore, the change of surface area in the reaction process due to losing oxygen could be easily calculated by combining it with pre-exponential parameters of Arrhenius equations. In conclusion, these kinetic parameters are verified by the experimental data for the process of ore reduced by carbon monoxide in a packed bed.展开更多
The objective of this work is using the online measurement method to study the process of precipitation of nickel hydroxide in a single-feed semi-batch stirred reactor with an internal diameter ofD = 240mm. The effect...The objective of this work is using the online measurement method to study the process of precipitation of nickel hydroxide in a single-feed semi-batch stirred reactor with an internal diameter ofD = 240mm. The effects of impeller speed, impeller type, impeller diameter and feed location on the mean particle size d43 and particle size distribution (PSD) were investigated, d43 and PSD were measured online using a Malvern Insitec Liquid Pro- cess Sizer every 20 s. It was found that d43 varied between 13 kwh and 26 lain under different operating conditions, and it decreased with increasing impeller diameter. When feeding at the off-bottom distance of D/2 under lower impeller speeds, d43 was significantly smaller than that at D/3. PSDs were slightly influenced by operating conditions.展开更多
Harmonic suppression, non-periodic and non-closing in straightness profile error that will bring about harmonic component distortion in measurement result are analyzed. The countermeasure-a novel accurate two-probe me...Harmonic suppression, non-periodic and non-closing in straightness profile error that will bring about harmonic component distortion in measurement result are analyzed. The countermeasure-a novel accurate two-probe method in time domain is put forward to measure straight-going component motion error in machine tools based on the frequency domain 3-point method after symmetrical continuation of probes' primitive signal. Both straight-going component motion error in machine tools and the profile error in workpiece that is manufactured on this machine can be measured at the same time. The information is available to diagnose the fault origin of machine tools. The analysis result is proved to be correct by the experiment.展开更多
A flexible calibration method based on a front-coated flat mirror is proposed for a laser light-sectioning three-dimensional(3D)measurement system. Since the calibration target and its mirror image are spatially separ...A flexible calibration method based on a front-coated flat mirror is proposed for a laser light-sectioning three-dimensional(3D)measurement system. Since the calibration target and its mirror image are spatially separated and can be recorded in an image by a camera,the proposed method requires only a single composite image that contains a non-planar checkerboard pattern,a laser strip projected on the target and their mirror images to complete the calibration of the camera and the laser plane in one step. Levenberg-Marquardt(LM)algorithm is used to optimize the system parameters,and the measurement accuracy and speed are improved to enable online 3D inspection. Static and dynamic online 3D measurements are carried out on a cup and a triple stepped shaft,respectively,to validate the proposed method. The shaft has two steps with the depth of(0.5±0.01)mm and(2±0.01)mm to be measured online when the shaft is rotated and translated at the same time. The measurement results can be output at a frequency of 7 to 11 readings per second with standard deviations of 0.040 mm and 0.051 mm. The experimental results verify the effectiveness and flexibility of the proposed method.展开更多
Electrochemical impedance spectroscopy (EIS) is widely used in fuel cell impedance analysis. However, for ohmic resistance (R Ω), EIS has some disadvantages such as long test period and complex data analysis with equ...Electrochemical impedance spectroscopy (EIS) is widely used in fuel cell impedance analysis. However, for ohmic resistance (R Ω), EIS has some disadvantages such as long test period and complex data analysis with equivalent circuits. Therefore, the current interruption method is explored to measure the value of RΩ in direct methanol fuel cells (DMFC) at different temperatures and current densities. It is found that RΩ decreases as temperature increase, and decreases initially and then increases as current density increases. These results are consistent with those measured by the EIS technique. In most cases, the ohmic resistances with current interruption (R iR ) are larger than those with EIS (R EIS ), but the difference is small, in the range from –0.848% to 5.337%. The errors of R iR at high current densities are less than those of R EIS . Our results show that the R iR data are reliable and easy to obtain in the measurement of ohmic resistance in DMFC.展开更多
文摘The in-situ instrumentation technique for measuring mercury and itsspeciation downstream a utility 100 MW pulverized coal (PC) fired boiler system was developed andconducted by the use of the Ontario hydro method (OHM) consistent with American standard test methodtogether with the semi-continuous emissions monitoring (SCEM) system as well as a mobile laboratoryfor mercury monitoring. The mercury and its speciation concentrations including participate mercuryat three locations of before air preheater, before electrostatic precipitator (ESP) and after ESPwere measured using the OHM and SCEM methods under normal operation conditions of the boiler systemas a result of firing a bituminous coal. The vapor-phase total mercury Hg(VT) concentration declinedwith the decrease of flue gas temperature because of mercury species transformation from oxidizedmercury to particulate mercury as the flue gas moved downstream from the air preheater to the ESPand after the ESP. A good agreement for Hg°, Hg^(2+) and Hg( VT) was obtained between the twomethods in the ash-free area. But in the dense particle-laden flue gas area, there appeared to be abig bias for mercury speciation owing to dust cake formed in the filter of OHM sampling probe. Theparticulateaffinity to the flue gas mercury and the impacts of sampling condition to accuracy ofmeasure were discussed.
文摘Using the ideal gas state equation, an on-line measuring method for the shell chamber volume is studied in this paper. After analyzing how various measurement parameters affect the measurement accuracy, the system parameters are optimized in this method. Because the shape and volume of the tested items are similar, the method of using "tamping" to raise the accuracy and speed of the measurement is put forward. Based on the work above, a prototype of the testing instrument for shell chamber volume was developed, automatically testing and controlling. Compared with the method of "water weight", this method is more accurate, quicker and more automotive, so it is adaptable for the use of on-line detection.
基金Supported by the State Key Development Program for Basic Research of China(2015CB251402)the National Natural Science Foundation of China(21206159)
文摘The intrinsic kinetics of iron oxide reduced by carbon monoxide is evaluated by a method of online measuring concentration of off-gas in an isothermal differential micro-packed bed. Under the condition of getting away from the influence of gas diffusion and gas–solid heat transfer and mass transfer, the reaction of Fe2O3 to Fe3O4, Fe3O4 to Fe O and Fe O to Fe in the process of single reaction can be clearly distinguished from each other, and the relevant activation energy is characterized to be 75.4, 74.4, and 84.0 k J·mol-1, respectively. Therefore, the change of surface area in the reaction process due to losing oxygen could be easily calculated by combining it with pre-exponential parameters of Arrhenius equations. In conclusion, these kinetic parameters are verified by the experimental data for the process of ore reduced by carbon monoxide in a packed bed.
基金the State Key Development Program for Basic Research of China(2013CB632601)the National High Technology Research and Development Program of China(2011AA060704)+1 种基金the National Natural Science Foundation of China(21476236,91434126)the National Science Fund for Distinguished Young Scholars(21025627)
文摘The objective of this work is using the online measurement method to study the process of precipitation of nickel hydroxide in a single-feed semi-batch stirred reactor with an internal diameter ofD = 240mm. The effects of impeller speed, impeller type, impeller diameter and feed location on the mean particle size d43 and particle size distribution (PSD) were investigated, d43 and PSD were measured online using a Malvern Insitec Liquid Pro- cess Sizer every 20 s. It was found that d43 varied between 13 kwh and 26 lain under different operating conditions, and it decreased with increasing impeller diameter. When feeding at the off-bottom distance of D/2 under lower impeller speeds, d43 was significantly smaller than that at D/3. PSDs were slightly influenced by operating conditions.
基金National Nature Science Foundation of China.No.50075056
文摘Harmonic suppression, non-periodic and non-closing in straightness profile error that will bring about harmonic component distortion in measurement result are analyzed. The countermeasure-a novel accurate two-probe method in time domain is put forward to measure straight-going component motion error in machine tools based on the frequency domain 3-point method after symmetrical continuation of probes' primitive signal. Both straight-going component motion error in machine tools and the profile error in workpiece that is manufactured on this machine can be measured at the same time. The information is available to diagnose the fault origin of machine tools. The analysis result is proved to be correct by the experiment.
基金supported in part by the National Natural Science Foundation of China (No. 11802132)the Natural Science Foundation of Jiangsu Province(No.BK20180446)。
文摘A flexible calibration method based on a front-coated flat mirror is proposed for a laser light-sectioning three-dimensional(3D)measurement system. Since the calibration target and its mirror image are spatially separated and can be recorded in an image by a camera,the proposed method requires only a single composite image that contains a non-planar checkerboard pattern,a laser strip projected on the target and their mirror images to complete the calibration of the camera and the laser plane in one step. Levenberg-Marquardt(LM)algorithm is used to optimize the system parameters,and the measurement accuracy and speed are improved to enable online 3D inspection. Static and dynamic online 3D measurements are carried out on a cup and a triple stepped shaft,respectively,to validate the proposed method. The shaft has two steps with the depth of(0.5±0.01)mm and(2±0.01)mm to be measured online when the shaft is rotated and translated at the same time. The measurement results can be output at a frequency of 7 to 11 readings per second with standard deviations of 0.040 mm and 0.051 mm. The experimental results verify the effectiveness and flexibility of the proposed method.
基金Supported by the National High Technology Research and Development Program of China (2007AA05Z150) the National Natural Science Foundation of China (50911140287 50973055)
文摘Electrochemical impedance spectroscopy (EIS) is widely used in fuel cell impedance analysis. However, for ohmic resistance (R Ω), EIS has some disadvantages such as long test period and complex data analysis with equivalent circuits. Therefore, the current interruption method is explored to measure the value of RΩ in direct methanol fuel cells (DMFC) at different temperatures and current densities. It is found that RΩ decreases as temperature increase, and decreases initially and then increases as current density increases. These results are consistent with those measured by the EIS technique. In most cases, the ohmic resistances with current interruption (R iR ) are larger than those with EIS (R EIS ), but the difference is small, in the range from –0.848% to 5.337%. The errors of R iR at high current densities are less than those of R EIS . Our results show that the R iR data are reliable and easy to obtain in the measurement of ohmic resistance in DMFC.