De Density, , Por oros osity, , and Heat Capacity Ch Characteri ristics of Ash Deposits from a 1.5 M a 1. 5 MW C Coal F al Fur urnac nace Oxyfuel Technologies I The 41 st International Technical Conference on Clean Coal & Fuel Systems Lauren Kolczynski, Andrew Fry, Teri Draper, Terry Ring and Eric Eddings Department of Chemical Engineering, University of Utah
In Intr troduc ductio tion • Carbon-Capture Multidisciplinary Simulation Center • Simulations of oxy-coal boilers • Model uncertainty reduced and characterized through experimental validation and verification/uncertainty quantification (V&V/UQ) • Vary, compare, and contrast experiment and analysis techniques to capture uncertainty and error ccmsc.utah.edu
Heat Hea t Trans ansfer er Deposit Reflected Radiation & "#$ ' 3 /012 3 "#$ Radiation , -,/012 , -,"#$ from Flame ! /012 ! "#$ ' + /012 + "#$ Emitted Radiation % # * ( "#$ )% # Heat Transfer Surface or Furnace Wall
Hea Heat t Trans ansfer er & = re reDlectivity ( = em emissivity ! = th therm rmal con conduct uctivity Deposit Reflected 3 = th therm rmal di diffusi sivity Radiation + = de densi sity & "#$ ' , - = he heat ca capaci city 3 /012 3 "#$ Radiation , -,/012 , -,"#$ from Flame ! /012 ! "#$ ' + /012 + "#$ Emitted Radiation % # * ( "#$ )% # Heat Transfer Surface or Furnace Wall
Hea Heat t Trans ansfer er & = re reDlectivity ( = em emissivity ! = th therm rmal con conduct uctivity Deposit Reflected 3 = th therm rmal di diffusi sivity Radiation + = de densi sity & "#$ ' , - = he heat ca capaci city 3 /012 3 "#$ Radiation , -,/012 , -,"#$ from Flame ! /012 ! "#$ ' Tube/Wall + /012 + "#$ Emitted Characterized at Radiation % # * ( "#$ )% # high temperature Heat Transfer Surface or Furnace Wall
Hea Heat t Trans ansfer er & = re reDlectivity ( = em emissivity ! = th therm rmal con conduct uctivity Deposit Reflected 3 = th therm rmal di diffusi sivity Radiation + = de densi sity & "#$ ' , - = he heat ca capaci city 3 /012 3 "#$ Radiation , -,/012 , -,"#$ from Flame ! /012 ! "#$ ' Tube/Wall Ash/Slag + /012 + "#$ Emitted ? Characterized at Radiation % # * ( "#$ )% # high temperature Heat Transfer Surface or Furnace Wall
Hea Heat t Trans ansfer er & = re reDlectivity ( = em emissivity ! = th therm rmal con conduct uctivity Deposit Reflected 3 = th therm rmal di diffusi sivity Radiation + = de densi sity & "#$ ' , - = he heat ca capaci city 3 /012 3 "#$ Radiation , -,/012 , -,"#$ from Flame ! /012 ! "#$ ' Tube/Wall Ash/Slag + /012 + "#$ Emitted ? Characterized at Radiation % # * ( "#$ )% # high temperature Heat Transfer Surface or Furnace Wall
Depo eposits ts • Highly variable • Emissivity • Previous study with room temperature FTIR • Thermal Conductivity # • ! = $% & • ' = (!) * • Temperature dependence
Expe Experimental Desi sign gn • Industrial Combustion And Gasification Research Facility • L-1500 Multifuel Furnace • 1.1m by 1.1m internal cross-section • 13.1m in length • February 2015 oxy-coal campaign • Utah Sufco coal • Firing rate ~1.0 MW (3.5 MBtu/hr) • Coal feed rate: ~135 kg/hr (297 lb/hr) • Avg. excess oxygen ~3% • Exhaust CO2 ~86-88% • Surface temperature (ceiling): ~1052 ˚C (1925 ˚F)
Expe Experimental Desi sign gn • ~400 total sampling sights throughout the furnace in a 1 ft x 1 ft grid Ceiling Right Wall • Surfaces: left wall, ceiling, & right wall Left Wall • Twelve sampling sights chosen for preliminary study • Location: midline of each surface • Depth: 1, 2, 3, and 4 feet from burner on each surface • Highly radiative section of the Burner furnace
Expe Experimental Desi sign gn • ~400 total sampling sights throughout the furnace in a 1 ft x 1 ft grid Ceiling Right Wall • Surfaces: left wall, ceiling, & right wall Left Wall • Twelve sampling sights chosen for a preliminary study • Location: midline of each surface • Depth: 1, 2, 3, and 4 feet from burner on each surface • Highly radiative section of the Burner furnace Left Wall Ceiling Right Wall = sampling location = flame
Sa Samp mples Depth from Burner Along Surface Midline [ft] 1 2 3 4 Right Surface Ceiling Left
Left Wall Ceiling Right Wall Porosity Po = samples = flame • Porosity Left Ceiling Right # $%&'( 0.35 • ! = $%&'( ×100% # (%)*+ ,# 0.3 • Total pore volume • BET analysis 0.25 Porosity [%] • Total solid volume 0.2 • Pycnometry 0.15 • Very low for all three surfaces • Porosity does not appear to be a strong 0.1 function of depth for the first four feet of 0.05 the furnace • Slightly higher in the left and right walls 0 than in the ceiling 1 2 3 4 • C Depth from Burner [ft]
Po Porosity • Porosity Left Ceiling Right # $%&'( 0.35 • ! = $%&'( ×100% # (%)*+ ,# 0.3 • Total pore volume • BET analysis 0.25 Porosity [%] • Total solid volume 0.2 • Pycnometry 0.15 • Very low for all three surfaces • Porosity does not appear to be a strong 0.1 function of depth for the first four feet of 0.05 the furnace • Slightly higher in the left and right walls 0 than in the ceiling 1 2 3 4 • Ceiling deposits molten during operation Depth from Burner [ft]
Th Thermal Conductivity - Me Method od • Measurements of , , - , and . / for deposit samples • Higher temperature regimes when available ( , , . / ) ! "## = % &"'( ) &"'( *+ &"'(
Th Thermal Conductivity - Me Method od • Measurements of , , - , and . / for deposit samples • Higher temperature regimes when available ( , , . / ) ! "## = % &"'( ) &"'( *+ &"'( Automatic Helium Gas Pycnometry
Th Thermal Conductivity - Me Method od • Measurements of , , - , and . / for deposit samples • Higher temperature regimes when available ( , , . / ) ! "## = % &"'( ) &"'( *+ &"'( IR Camera Thermal Image Processing Automatic Helium Gas Pycnometry
Th Thermal Conductivity - Me Method od • Measurements of , , - , and . / for deposit samples • Higher temperature regimes when available ( , , . / ) ! "## = % &"'( ) &"'( *+ &"'( Differential Scanning Calorimetry IR Camera Thermal Image Processing Automatic Helium Gas Pycnometry
Th Thermal Conductivity - Me Method od • Measurements of , , - , and . / for deposit samples • Higher temperature regimes when available ( , , . / ) ! "## = % &"'( ) &"'( *+ &"'( Differential Scanning Calorimetry IR Camera Thermal Image Processing Automatic Helium Gas Pycnometry
Left Wall Ceiling Right Wall Sol Solid D Density = samples = flame Left Ceiling Right 2.8 2.78 2.76 2.74 Density [g/cm3] 2.72 • Pycnometry 2.7 + ,-. ! "#$% = ! '()) − • /01 /21 34 2.68 $ 2.66 • 5 = + 2.64 • Direct measurement of true (skeletal) density of samples 2.62 Three replicates to capture instrument run error • • 2 x Std. Dev. 2.6 1 2 3 4 DDen • Depth from Burner [ft]
Left Wall Ceiling Right Wall Sol Solid D Density = samples = flame Left Ceiling Right 3 2.5 Density [g/cm3] 2 • Pycnometry 1.5 + ,-. ! "#$% = ! '()) − • /01 /21 34 1 $ • 5 = + • Direct measurement of true (skeletal) density of samples 0.5 Three replicates to capture instrument run error • • 2 x Std. Dev. 0 1 2 3 4 Density does not appear to be a strong function of depth for • the first four feet of the furnace Depth from Burner [ft]
Left Wall Ceiling Right Wall Thermal Diffusivity Th = samples = flame • Thermal diffusivity determined in previous work using novel Left Ceiling Right technique 40 • Surfaces covered in deposit were heated using an oxy- Thermal Diffusivity × 10 -7 [m 2 /s] acetylene torch 35 • Infrared camera video was taken of the heated area 30 • Diminishing area of the heat was tracked with MATLAB using a threshold value 25 • Two-dimensional radius used to approximate hemispherical 20 volume of dissipating heat 15 • The slope of the heat volume versus time was compared to a COMSOL simulation of pure refractory and related to yield 10 the thermal diffusivity. • Three replicates to capture measurement error 5 • 1 x Std. Dev. 0 • Thermal diffusivity does not appear to be a function of depth 1 2 3 4 for the first four feet of the furnace Depth from Burner [ft] Courtesy Teri Draper
Hea Heat t Capac apacity ity • Differential scanning calorimetry • Direct measurement of heat Heat Capacity flow [J/kg*K] • Heat capacity calculated Run 1 1404 Run 2 1884 $ ('(/*+) • ! " = % (*-/*+) Average 1644 • Data at 700 ˚C for ceiling sample Std. Dev. 340 at 1 ft depth – two runs 2 x Std. Dev. 680 • Low enough temperature to avoid molten state and glass transition • High standard deviation
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