Bonin, MP
1993
Experimentally Determined Particle Number Density Statistics in an Industrial-Scal, Pulverized-Coal-Fired Boiler
Queiroz, M.; Bonin, M.P.; Shirolkar, J.S. and Dawson, R.W.
Energy & Fuels 7:(6) 842-851, 1993. Funded by ACERC.
A study on the variations of particle data rate statistics and the probability density function (PDF) of cumulative particle number density has been completed in a full-scale, tangentially fired, 85 MWe pulverized-coal-fired boiler. Variables in the tests included boiler load and coal type. It was observed that particle data rate fluctuations were greater in magnitude for small particles (<3.5 µm) and that the PDFs of particle data rate were well approximated by normal distributions. Furthermore, there were no preferential frequencies in the large (<3.5 µm) or small particle data rate fluctuations anywhere in the boiler. The PDFs of cumulative particle number density for the small particles were negatively skewed and, as compared to the large particle PDFs, were less sensitive to boiler location. The large particle PDFs were more negatively skewed near the walls and more Gaussian as distance from the wall increased. Broader distributions of cumulative particle number density with peaks at higher values were observed for the small particles for the coal with lower volatiles and higher ash content. Moreover, for the large particles, a noticeable shift of the PDFs, longer "tails" toward higher cumulative number densities, and a substantial flattening of the PDF curves were observed for the same coal. The shape of the PDF profiles did not change substantially as the boiler load changed. The effect of a lighter load on the small particle PDFs was to slightly broaden the distribution, mostly in the direction of large cumulative particle number densities. For the large particles, a shift toward higher cumulative particle number densities, a slightly broadening effect, and a reduction in the maximum PDF values were observed at lighter load.
1992
Optical Measurement of Particle Size, Velocity and Number Density in Two-Phase, Isothermal and Reacting Flows
Bonin, M.P.
Optical Measurement of Particle Size, Velocity and Number Density in Two-Phase, Isothermal and Reacting Flows, Ph.D./BYU, April 1992. Advisor: Queiroz
The Effects of Different Coals on Combustion Parameters Measured in a Full-Scale Utility Boiler
Cannon, J.N.; Webb, B.W. and Bonin, M.P.
Heat Rate Improvement Conference, Birmingham, AL, November 1992. Funded by Empire State Electric Energy Research Corp. and ACERC.
Brigham Young University/Advanced Combustion Engineering Research Center (BYU/ACERC) has been measuring combustion parameters in full-scale utility boilers with the intent of validating computer combustion models of coal burning processes throughout the boiler interior. Measurements were made in the burner region, fireball region and beyond the economizer. These measurements are spatially resolved for particle and gas temperature, particle size distribution, concentration and velocity, radiation and total wall flux, combustion gas products and pollutants (i.e. CO, CO2, O2, NO, and SOx) plus gas velocity and direction as well as turbulence intensity. In addition, in situ ash samples were collected.
Two bituminous coals were used in the test series conducted in the summer of 1991 at the New York State Gas and Electric (NYSGE) Goudey Station in Johnson City, New York. The test series variables were two different loads at two different excess air settings for two different coals and with pulverizer settings and burner tilt held constant. Tests were not conducted during soot and wall blowing periods. The two coals tested were both bituminous coals of similar heating value and ultimate analysis but differed in Hargrove Grindability Index (HGI), percent volatiles and ash properties.
The results indicate that most of the measured quantities could distinguish between the two relatively similar coals both in magnitude and location, highlighting the difference in burning characteristics of the two coals. These measured differences provide an explanation to why power plant operators respond to even similar coals as they do and gives credence to those actions. Seemingly small differences in a coal can make a significant difference in furnace behavior quantitatively. Internal boiler measurements of this kind are used to validate the computer combustion modeling programs.
1991
Local Particle Velocity, Size and Concentration Measurements in an Industrial Scale Pulverized Coal Fired Boiler
Bonin, M.P. and Queiroz, M.
Combustion and Flame, 85:121-133, 1991. Funded by ACERC.
Parametric, in-situ, particle velocity, size and number density measurements have been made in a full scale, coal burning power plant using an optical diagnostic technique. Available ports in the boiler allowed measurement at three locations above the burner level. Variable test parameters included furnace load, excess air, and burner tilt, using a medium volatile bituminous coal. Higher particle velocities were observed when the boiler was operated at a maximum capacity due to increased air and coal flows. Port-to-port velocity variations were attributed to the rotational nature of the mean flow, changes in gas density with changing gas temperature, and the interaction of the flow with the boiler nose. Measured particle number density profiles were characterized by high values in the small particle size class (< 2 µm), decreasing exponentially with increasing particle size. The measured number density profiles indicated that the combustion process is largely complete at locations 7 m above the burners and that the particles measured consisted primarily of ash, a conclusion that is also supported by the percent carbon-in-ash data. The mass-mean and number-mean particle sizes for all tests varied between 10 and 45, and 0.5 and 0.85 µm, respectively. The characteristic similarity between the particle size distribution of the ash and that of the parent char, previously documented in laboratory scale investigations, was also observed in the present study. Cumulative mass distribution profiles indicated that a significant centrifugal effect is exerted on the condensed phase by the rotating flow. An increase in small particle number density (~ 0.5 µm) was also apparent at lower boiler loads due to changes in the combustion process occurring at these operating conditions, which affect the various modes of ash particle formation.
1990
An Analysis of Single Stream Droplet Combustion Through Size and Velocity Measurements
Bonin, M.P. and Queiroz, M.
The American Society of Mechanical Engineers, New York, HTD-142, 57-66, Farouk, B. et al., Eds., Heat Transfer in Combustion Systems, 1990. Funded by ACERC.
A commercially available, laser-based particle analyzer capable of measuring the distribution of size and velocity of particles in a two-phase reacting flow has been applied to a monodispersed stream of liquid droplets burning in a turbulent, co-flowing air stream. Previous applications of this instrument have focused on light absorbing particles such as pulverized coal, coal slurries or powdered metals. The present study describes the first documented application of this sizing technique to light droplets larger than 100 µm, including the development of an instrument response function specific to non-absorbing particles in this size class.
A parametric study which investigated the influence of gas-phase turbulence, fuel type, and initial droplet size on the droplet vaporization rate was conducted. Gas phase temperature and velocity measurements were made using thermocouples and hot wire anemometry. Comparisons between measured and predicted droplet size using single droplet evaporation theories indicate a lower experimental value resulting from group combustion effects. Limitations in single stream measurements have been encountered in the lower portion of the flame, relative to the uniform particle flux requirement in the sample volume. Under certain experimental condition, droplet coalescence was also observed downstream of the ignition point.
Local Particle Velocity, Size and Concentration Measurements in an Industrial Scale Pulverized Coal Fired Boiler
Bonin, M.P. and Queiroz, M.
Combustion and Flame, 1990 (In press). Funded by ACERC.
Parametric, in-situ, particle velocity, size and number density measurements have been made in a full scale, coal burning power plant using an optical diagnostic technique. Available ports in the boiler allowed measurement at three locations above the burner level. Variable test parameters included furnace load, excess air, and burner tilt, using a medium volatile bituminous coal. Higher particle velocities were observed when the boiler was operated at a maximum capacity due to increased air and coal flows. Port-to-port velocity variations were attributed to the rotational nature of the mean flow, changes in gas density with changing gas temperature, and the interaction of the flow with the boiler nose. Measured particle number density profiles were characterized by high values in the small particle size class (< 2 µm), decreasing exponentially with increasing particle size. The measured number density profiles indicated that the combustion process is largely complete at locations 7 m above the burners and that the particles measured consisted primarily of ash, a conclusion that is also supported by the percent carbon-in-ash data. The mass-mean and number-mean particle sizes for all tests varied between 10 and 45, and 0.5 and 0.85 µm, respectively. The characteristic similarity between the particle size distribution of the ash and that of the parent char, previously documented in laboratory scale investigations, was also observed in the present study. Cumulative mass distribution profiles indicated that a significant centrifugal effect is exerted on the condensed phase by the rotating flow. An increase in small particle number density (~ 0.5 µm) was also apparent at lower boiler loads due to changes in the combustion process occurring at these operating conditions, which affect the various modes of ash particle formation.
1989
Non-Intrusive Analysis of Single Stream Droplet Combustion Through Size and Velocity Measurement
Bonin, M.P. and Queiroz, M.
Western States Section, The Combustion Institute, Pullman, Washington, 1989. Funded by ACERC (National Science Foundation and Associates and Affiliates).
A newly-developed, laser based instrument which is capable of non-intrusively measuring the size and velocity distribution of particles in a two-phase reacting flow has been applied to a monodispersed stream of liquid fuel droplets burning in a turbulent, co-flowing air stream. This instrument determines the size distribution of particles having diameters ranging from 0.5 to 200 mm with corresponding velocities as high as 400 m/s. Therefore, the instrument is a valuable diagnostic tool for the investigation of both simplified and more complex spray flames. Measurement uncertainty is typically ten percent of the indicated droplet size.
Previous applications of the instrument were primarily concerned with size measurement in light absorbing environments consisting of solid particles such as coal, coal slurries or powdered metals. The present study describes the first documented application of this sizing technique to liquid fuel droplets. Before actual measurements were made, an appropriate instrument response function specific to non-absorbing (liquid) particles was created. With the corrected response function, a parametric examination of a simplified spray flame was undertaken to demonstrate the sizing capability of the instrument under non-absorbing conditions. The parametric study was designed to track the influence of variable turbulence intensity, fuel type and initial droplet size on the droplet vaporization rate. Temperature measurements made with digitally compensated thermocouples further quantified the mechanisms affecting the droplet size history. Hot-wire measurements were also performed to characterize the co-flowing air stream. Comparisons between measured and predicted droplet sizes using single droplet evaporation theories indicate a lower experimental value resulting from group combustion effects. Under certain experimental conditions, droplet agglomeration was observed downstream of the ignition point. The cause of the agglomeration is not clear, however it is thought to result from droplet collision and subsequent coalescence in the turbulent flow.
Bonin, MP
1993
Experimentally Determined Particle Number Density Statistics in an Industrial-Scal, Pulverized-Coal-Fired Boiler
Queiroz, M.; Bonin, M.P.; Shirolkar, J.S. and Dawson, R.W.
Energy & Fuels 7:(6) 842-851, 1993. Funded by ACERC.
A study on the variations of particle data rate statistics and the probability density function (PDF) of cumulative particle number density has been completed in a full-scale, tangentially fired, 85 MWe pulverized-coal-fired boiler. Variables in the tests included boiler load and coal type. It was observed that particle data rate fluctuations were greater in magnitude for small particles (<3.5 µm) and that the PDFs of particle data rate were well approximated by normal distributions. Furthermore, there were no preferential frequencies in the large (<3.5 µm) or small particle data rate fluctuations anywhere in the boiler. The PDFs of cumulative particle number density for the small particles were negatively skewed and, as compared to the large particle PDFs, were less sensitive to boiler location. The large particle PDFs were more negatively skewed near the walls and more Gaussian as distance from the wall increased. Broader distributions of cumulative particle number density with peaks at higher values were observed for the small particles for the coal with lower volatiles and higher ash content. Moreover, for the large particles, a noticeable shift of the PDFs, longer "tails" toward higher cumulative number densities, and a substantial flattening of the PDF curves were observed for the same coal. The shape of the PDF profiles did not change substantially as the boiler load changed. The effect of a lighter load on the small particle PDFs was to slightly broaden the distribution, mostly in the direction of large cumulative particle number densities. For the large particles, a shift toward higher cumulative particle number densities, a slightly broadening effect, and a reduction in the maximum PDF values were observed at lighter load.
1992
Optical Measurement of Particle Size, Velocity and Number Density in Two-Phase, Isothermal and Reacting Flows
Bonin, M.P.
Optical Measurement of Particle Size, Velocity and Number Density in Two-Phase, Isothermal and Reacting Flows, Ph.D./BYU, April 1992. Advisor: Queiroz
The Effects of Different Coals on Combustion Parameters Measured in a Full-Scale Utility Boiler
Cannon, J.N.; Webb, B.W. and Bonin, M.P.
Heat Rate Improvement Conference, Birmingham, AL, November 1992. Funded by Empire State Electric Energy Research Corp. and ACERC.
Brigham Young University/Advanced Combustion Engineering Research Center (BYU/ACERC) has been measuring combustion parameters in full-scale utility boilers with the intent of validating computer combustion models of coal burning processes throughout the boiler interior. Measurements were made in the burner region, fireball region and beyond the economizer. These measurements are spatially resolved for particle and gas temperature, particle size distribution, concentration and velocity, radiation and total wall flux, combustion gas products and pollutants (i.e. CO, CO2, O2, NO, and SOx) plus gas velocity and direction as well as turbulence intensity. In addition, in situ ash samples were collected.
Two bituminous coals were used in the test series conducted in the summer of 1991 at the New York State Gas and Electric (NYSGE) Goudey Station in Johnson City, New York. The test series variables were two different loads at two different excess air settings for two different coals and with pulverizer settings and burner tilt held constant. Tests were not conducted during soot and wall blowing periods. The two coals tested were both bituminous coals of similar heating value and ultimate analysis but differed in Hargrove Grindability Index (HGI), percent volatiles and ash properties.
The results indicate that most of the measured quantities could distinguish between the two relatively similar coals both in magnitude and location, highlighting the difference in burning characteristics of the two coals. These measured differences provide an explanation to why power plant operators respond to even similar coals as they do and gives credence to those actions. Seemingly small differences in a coal can make a significant difference in furnace behavior quantitatively. Internal boiler measurements of this kind are used to validate the computer combustion modeling programs.
1991
Local Particle Velocity, Size and Concentration Measurements in an Industrial Scale Pulverized Coal Fired Boiler
Bonin, M.P. and Queiroz, M.
Combustion and Flame, 85:121-133, 1991. Funded by ACERC.
Parametric, in-situ, particle velocity, size and number density measurements have been made in a full scale, coal burning power plant using an optical diagnostic technique. Available ports in the boiler allowed measurement at three locations above the burner level. Variable test parameters included furnace load, excess air, and burner tilt, using a medium volatile bituminous coal. Higher particle velocities were observed when the boiler was operated at a maximum capacity due to increased air and coal flows. Port-to-port velocity variations were attributed to the rotational nature of the mean flow, changes in gas density with changing gas temperature, and the interaction of the flow with the boiler nose. Measured particle number density profiles were characterized by high values in the small particle size class (< 2 µm), decreasing exponentially with increasing particle size. The measured number density profiles indicated that the combustion process is largely complete at locations 7 m above the burners and that the particles measured consisted primarily of ash, a conclusion that is also supported by the percent carbon-in-ash data. The mass-mean and number-mean particle sizes for all tests varied between 10 and 45, and 0.5 and 0.85 µm, respectively. The characteristic similarity between the particle size distribution of the ash and that of the parent char, previously documented in laboratory scale investigations, was also observed in the present study. Cumulative mass distribution profiles indicated that a significant centrifugal effect is exerted on the condensed phase by the rotating flow. An increase in small particle number density (~ 0.5 µm) was also apparent at lower boiler loads due to changes in the combustion process occurring at these operating conditions, which affect the various modes of ash particle formation.
1990
An Analysis of Single Stream Droplet Combustion Through Size and Velocity Measurements
Bonin, M.P. and Queiroz, M.
The American Society of Mechanical Engineers, New York, HTD-142, 57-66, Farouk, B. et al., Eds., Heat Transfer in Combustion Systems, 1990. Funded by ACERC.
A commercially available, laser-based particle analyzer capable of measuring the distribution of size and velocity of particles in a two-phase reacting flow has been applied to a monodispersed stream of liquid droplets burning in a turbulent, co-flowing air stream. Previous applications of this instrument have focused on light absorbing particles such as pulverized coal, coal slurries or powdered metals. The present study describes the first documented application of this sizing technique to light droplets larger than 100 µm, including the development of an instrument response function specific to non-absorbing particles in this size class.
A parametric study which investigated the influence of gas-phase turbulence, fuel type, and initial droplet size on the droplet vaporization rate was conducted. Gas phase temperature and velocity measurements were made using thermocouples and hot wire anemometry. Comparisons between measured and predicted droplet size using single droplet evaporation theories indicate a lower experimental value resulting from group combustion effects. Limitations in single stream measurements have been encountered in the lower portion of the flame, relative to the uniform particle flux requirement in the sample volume. Under certain experimental condition, droplet coalescence was also observed downstream of the ignition point.
Local Particle Velocity, Size and Concentration Measurements in an Industrial Scale Pulverized Coal Fired Boiler
Bonin, M.P. and Queiroz, M.
Combustion and Flame, 1990 (In press). Funded by ACERC.
Parametric, in-situ, particle velocity, size and number density measurements have been made in a full scale, coal burning power plant using an optical diagnostic technique. Available ports in the boiler allowed measurement at three locations above the burner level. Variable test parameters included furnace load, excess air, and burner tilt, using a medium volatile bituminous coal. Higher particle velocities were observed when the boiler was operated at a maximum capacity due to increased air and coal flows. Port-to-port velocity variations were attributed to the rotational nature of the mean flow, changes in gas density with changing gas temperature, and the interaction of the flow with the boiler nose. Measured particle number density profiles were characterized by high values in the small particle size class (< 2 µm), decreasing exponentially with increasing particle size. The measured number density profiles indicated that the combustion process is largely complete at locations 7 m above the burners and that the particles measured consisted primarily of ash, a conclusion that is also supported by the percent carbon-in-ash data. The mass-mean and number-mean particle sizes for all tests varied between 10 and 45, and 0.5 and 0.85 µm, respectively. The characteristic similarity between the particle size distribution of the ash and that of the parent char, previously documented in laboratory scale investigations, was also observed in the present study. Cumulative mass distribution profiles indicated that a significant centrifugal effect is exerted on the condensed phase by the rotating flow. An increase in small particle number density (~ 0.5 µm) was also apparent at lower boiler loads due to changes in the combustion process occurring at these operating conditions, which affect the various modes of ash particle formation.
1989
Non-Intrusive Analysis of Single Stream Droplet Combustion Through Size and Velocity Measurement
Bonin, M.P. and Queiroz, M.
Western States Section, The Combustion Institute, Pullman, Washington, 1989. Funded by ACERC (National Science Foundation and Associates and Affiliates).
A newly-developed, laser based instrument which is capable of non-intrusively measuring the size and velocity distribution of particles in a two-phase reacting flow has been applied to a monodispersed stream of liquid fuel droplets burning in a turbulent, co-flowing air stream. This instrument determines the size distribution of particles having diameters ranging from 0.5 to 200 mm with corresponding velocities as high as 400 m/s. Therefore, the instrument is a valuable diagnostic tool for the investigation of both simplified and more complex spray flames. Measurement uncertainty is typically ten percent of the indicated droplet size.
Previous applications of the instrument were primarily concerned with size measurement in light absorbing environments consisting of solid particles such as coal, coal slurries or powdered metals. The present study describes the first documented application of this sizing technique to liquid fuel droplets. Before actual measurements were made, an appropriate instrument response function specific to non-absorbing (liquid) particles was created. With the corrected response function, a parametric examination of a simplified spray flame was undertaken to demonstrate the sizing capability of the instrument under non-absorbing conditions. The parametric study was designed to track the influence of variable turbulence intensity, fuel type and initial droplet size on the droplet vaporization rate. Temperature measurements made with digitally compensated thermocouples further quantified the mechanisms affecting the droplet size history. Hot-wire measurements were also performed to characterize the co-flowing air stream. Comparisons between measured and predicted droplet sizes using single droplet evaporation theories indicate a lower experimental value resulting from group combustion effects. Under certain experimental conditions, droplet agglomeration was observed downstream of the ignition point. The cause of the agglomeration is not clear, however it is thought to result from droplet collision and subsequent coalescence in the turbulent flow.