Pilot-Scale Investigation of Heat Flux, Radiation and CO Distribution from an OxyCoal Flame Andrew Fry, Jennifer Spinti, Oscar Diaz-Ibarra, Ignacio Preciado, Teri Draper, Eric Eddings, Terry Ring University of Utah, Institute for Clean and Secure Energy U.S. Department of Energy, Agreement # DE-NA0002375 2015 AIChE Annual Meeting
Presentation Road Map • Project Overview • Experimental Setup • Initial Modeling Efforts • Heat Removal and Radiation Data • Summary & Conclusions • Questions
Presentation Road Map • Project Overview • Experimental Setup • Initial Modeling Efforts • Heat Removal and Radiation Data • Summary & Conclusions • Questions
Project Objective Implementation of exascale computing with V&V/UQ to more rapidly deploy a new technology for providing low cost, low emission electric power generation V&V/UQ – Verification & Validation with Uncertainty Quantification
Project Objective • V/UQ performed on data produced at 4 scales – Bench-scale, Lab-scale (~100 kWth), Large-scale (~1-5 MWth), Pilot-scale (~15 MWth) • Ultimate goal to design a next-generation 350 MWe oxy-coal boiler • Year 1 of a 5 year program is complete • Focus here will be on a 1.5 MWth data set
Presentation Road Map • Project Overview • Experimental Setup • Initial Modeling Efforts • Heat Removal and Radiation Data • Summary & Conclusions • Questions
5.0 MBtu/hr Pilot-Scale Furnace (L1500) Unique L1500 Capabilities: - Realistic Burner Turbulent Mixing Scale - Realistic Radiative Conditions - Realistic Time – Temperature Profile Radiative Section Baghouse Air/FGR/O 2 Control Convective Section Burner FD and Recycle Fan Sample Ports
Dual Register Low-NO x Burner (LNB) Outer Secondary Air or O 2 /FGR Mixture Inner Secondary Air or O 2 /FGR Mixture Natural Gas (For heat up) Primary (Coal carrier) Bluff Body (Not installed in these tests)
Furnace Cooling Coils and Plates Cooling Coils (8 installed) Cooling Plates (3 installed) Heat removal by cooling surfaces is determined by measuring cooling water flow and temperature in and out
Radiometer Configuration L p1 L p2 D 1 D 2 Field of view Sensing Focusing Water-cooled jacket thermistors lens α field of view = 2 * Tan -1 ((D 2 /2)/L p2 ) = 2.74 Three radiometers are installed opposite the cooling plates. Angle of view Includes only the cooling plate surface Black body radiator was used to calibrate these devices
Radiometer Configuration
Infrared Heat Flux Measurement At times placed in one of the first three sections Across from the cooling plates FLIR infrared camera in the wavelength range of 3825–3975 nm. The camera was calibrated with a blackbody generator, which is a source of known emission, in order to obtain infrared heat flux data.
Experimental Conditions Targeted and Actual Conditions Utah Sufco Coal Composition Units Target 0% Swirl 100% Swirl Firing Rate Btu/hr 3.5 C 66.9 Coal Rate lb/hr 297.0 297.0 296.9 H 4.5 Primary FGR lb/hr 450.2 461.9 461.7 N 1.2 Primary O 2 lb/hr 85.3 86.4 86.3 S 0.4 Inner Secondary FGR lb/hr 361.9 362.0 362.0 O 13.6 Inner Secondary O 2 lb/hr 105.9 114.0 106.3 Ash 7.9 Inner Secondary Temp ˚F 500.0 496.2 502.3 Moisture 5.6 Outer Secondary FGR lb/hr 1448.6 1440.3 1449.2 Volatile Matter 40.4 Outer Secondary O 2 lb/hr 422.6 418.2 418.4 Fixed Carbon 46.1 Outer Secondary Temp ˚F 500.0 498.6 501.9 HHV, Btu/lb 11,765 * all values in mass % unless otherwise specified O 2 % 3.0 2.6 2.9 CO 2 % 96.1 85.7 88.2 Difference in CO 2 concentration due to air leakage, which occurs mainly through the FGR recycle fan and is a function of back pressure through the burner. More leakage occurs at 0% swirl condition
Presentation Road Map • Project Overview • Experimental Setup • Initial Modeling Efforts • Heat Removal and Radiation Data • Summary & Conclusions • Questions
Experimental and Predicted Values Gas temperature profile Prediction and measurement of predictions using LES model cooling coil heat flux model experiment We have high confidence in our ability to accurately represent gas-phase and entrained particle properties (emissivity, heat capacity) Why then the disconnect between model and experiment?
Presentation Road Map • Project Overview • Experimental Setup • Initial Modeling Efforts • Heat Removal and Radiation Data • Summary & Conclusions • Questions
Cooling Coil Data (Change from 0 to 100% Swirl) South Cooling Coils North Cooling Coils 220000 220000 0 Swirl 100 Swirl 0 Swirl 100 Swirl 200000 Heat Removal (Btu/hr) 200000 Heat Removal (Btu/hr) 180000 180000 160000 160000 140000 140000 120000 120000 100000 100000 Sec 1 Sec 2 Sec 3 Sec 4 Sec 1 Sec 2 Sec 3 Sec 4 220000 220000 200000 200000 Change from Section 1 0% to 100% Heat Removal (Btu/hr) Section 2 Heat Removal (Btu/hr) Swirl 180000 180000 Section 3 Section 1 Section 4 Section 2 160000 160000 Section 3 Section 4 140000 140000 Change from 120000 120000 0% to 100% Swirl 100000 100000 12:50:01 12:51:27 12:52:54 12:54:20 12:55:47 12:57:13 12:58:39 13:00:06 12:50:01 12:51:27 12:52:54 12:54:20 12:55:47 12:57:13 12:58:39 13:00:06
Cooling Coil Data (Long Times) South Cooling Coils North Cooling Coils 220000 220000 200000 200000 Change from Section 1 0% to 100% Heat Removal (Btu/hr) Section 2 Heat Removal (Btu/hr) Swirl 180000 180000 Section 3 Section 1 Section 4 Section 2 160000 160000 Section 3 Section 4 140000 140000 Change from 120000 120000 0% to 100% Swirl 100000 100000 10:48:00 12:00:00 13:12:00 14:24:00 10:48:00 12:00:00 13:12:00 14:24:00 Heat removal through the cooling tubes steadily decreases This is consistent with increasing insulating layer thickness due to deposition
Radiometer Data (Long Times) Radiometer 1 Radiometer 2 Section 1 Section 2 Radiometer 3 Section 3 66563 60224 53884 Heat Flux (Btu/ft 2 hr) 47545 41206 34866 28527 22188 0 % swirl 100 % swirl 0 % swirl 100 % swirl 15848 Time Time Heat flux to radiometers increases steadily over time Wall temperatures are stable Why?
Infrared Heat Flux Data FLAME NO FLAME
Ash Deposits Deposit is extensive For 1 week of testing Probably peeled off during shut down
CO Distribution 0 % Swirl 100 % Swirl CO (ppmv) CO (ppmv) 0.0 0.0 4.3 4.3 5.5 Distance Distance 0.3 5.5 0.3 6.7 6.7 7.9 from 7.9 from 9.1 9.1 0.6 0.6 Center 10.4 10.4 Center Distance from Burner (m) Distance from Burner (m) 11.6 11.6 (m) (m)
Observations • An accurate prediction of heat flux through heat exchange surfaces requires: – Accurate representation of surface properties which are dominated by deposited mineral mater – Emissivity, thermal conductivity and deposit thickness must be known accurately • Predictive tool must include accurate representation of deposit rate and mineral composition
Presentation Road Map • Project Overview • Experimental Setup • Initial Modeling Efforts • Heat Removal and Radiation Data • Summary & Conclusions • Questions
Summary & Conclusions • An oxy-coal combustion data set was produced to be used for V&V/UQ • Air Leakage was higher than desired and occurs primarily in the recycle fan • Heat removal through the coils is sensitive to burner changes and consistent with expected flame behavior
Summary & Conclusions • Heat removal through the coils decreases continuously due to ash deposition on heat transfer surface • Radiometer data increases continuously due to ash buildup and change in surface emissivity • CFD Modeling is Underway – Trends in heat flux and temperature are well represented – Magnitude is not exact – Most likely due to assignment of surface boundary conditions (emissivity, conductivity, etc.)
Summary & Conclusions • Current efforts include: – Measurement of the physical properties of the ash containing surfaces • For the next round of testing the following modifications will be made: – Upgrade of recycle fan to reduce air inleakage – Addition of soot blowing for cooling tubes and plates
Presentation Road Map • Project Overview • Experimental Setup • Initial Modeling Efforts • Heat Removal and Radiation Data • Summary & Conclusions • Questions
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