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Building Environment Research & Education. Albert J. Heber, Associate Professor Director, Purdue Agricultural Air Quality Lab. AgAirQuality.com. Agricultural and Biological Engineering Purdue University. “A Buoyant Convective Flux Chamber for Measuring Liquid Surface Emissions”.
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Building Environment Research & Education Albert J. Heber, Associate ProfessorDirector, Purdue Agricultural Air Quality Lab AgAirQuality.com Agricultural and Biological Engineering Purdue University
“A Buoyant Convective Flux Chamber for Measuring Liquid Surface Emissions” A.J. Heber, T.T. Lim, J.Q. Ni and K.J. Fakhoury AgAirQuality.com hoodsunny
Objectives • Develop floating emission chamber • Evaluate performance Field Tests Lab Tests
Air Supply Unit Filter Adsorbent Blower
Air Supply Blower 198 m3/h (117 cfm)
Air Supply Filter 22.4 kg of adsorbent Charcoal Permanganate Zeolite
Top View Air velocity probe Liquid surface area = 0.76 m2 Air inlet Air outlet Stainless steel divider Sampling location Styrofoam boards for buoyancy
“Hairpin” Airflow Path 2.4 m path length 2.2 sec residence time
Side View Air inlet Air velocity probe Air outlet Sampling location 1.1 m/s
End View Sampling point Air Inlet Air Outlet Divider 31 cm
Lab Tests N-butanol at 250-20,250 ppm in 200 L water Odor emission only. Lagoon effluent: 100, 50 and 25% dilution H2S, NH3, CO2 and odor emission.
Gas Analyzers • Ammonia (0 to 200 ppm) • Ammonia converted to nitric oxide with a SS converter, 875 C • Chemiluminescense: PMT detects light emission from reaction of nitric oxide with ozone. • Sample flow rate = 0.5 Lpm • Hydrogen sulfide (0 to 10,000 ppb) • Hydrogen sulfide converted to sulfur dioxide, SO2 • Pulsed fluorescence: PMT detects UV from decaying SO2 molecules • Sample flow rate = 1.0 Lpm • Carbon dioxide (0 to 5,000 ppm) • Photoacoustic infrared sensor • Sample flow rate = 1.0 Lpm.
Instrumentation Room Manifolds Gas sensors PC
Odor Threshold Measurement 1 of 8 panelists Olfactometer Tedlar bag PC Panel leader’s hand
N-Butanol Test Results • Blank: 9 OU • Inlet mean: 10.4 OU (8 to 13 OU) • Odor emission: 0.5 to 11.2 OU/s-m2
Emission Rate of N-Butanol 12 155 2 Emission Rate = 5.10 Log(C) - 13.05 8 2 R = 0.82 Emission Rate, OU/s-m 4 63 51 20 27 0 100 1000 10000 100000 Concentration of N-butanol in Tank, ppm
Lagoon Effluent Test Results • Inlet mean: 22 OU • Outlet mean: 27 OU • Odor emission: 0.8 OU/s-m2 at 100% • Hydrogen sulfide too low to measure • Inlet ammonia mean: 1.8 ppm • Outlet ammonia mean: 2.9 ppm • Ammonia emission proportional to effluent concentration. • Ammonia levels below odor threshold
Lagoon Effluent: NH3 Emission 400 2 300 Emission Rate, mg/hr-m 200 Emission Rate = 4.15x - 18.1 2 R = 0.90 100 0 0 20 40 60 80 100 120 Lagoon Effluent Dilution, % Solids: 0.16%
Field Tests • Swine grow-finish facility • Four consecutive days • Day 1: Effect of air speed crustincorner
Anaerobic Treatment Lagoons Six Swine Buildings 1st Stage Basin 2nd Stage Basin
Odor Emission Tests Raceway (6 m) 3 Lpm pumps Air velocity control Evacuation chamber hoodwtwovacs Hammer
Chamber Inlet and Outlet Samples hebervacus
Emission vs. Air Speed 4 Measured Predicted 3 2 Emission, OU/m2-s 0.93 Emission = 1.85 x 1 2 R = 0.88 0 0.0 0.5 1.0 1.5 2.0 Surface Air Speed, m/s
Field Test Results • Inlet mean: 23 OU (12 to 42 OU) • Outlet mean: 52 OU • Odor emission: 1.5 to 2.1 OU/s-m2 • Mean of 1.7 OU/s-m2 corresponded to 1,000 ppm n-butanol.
Advantages • Large air filtration and cleaning unit • Inlet air sampling • Large liquid surface area • Long air path
Disadvantages • Size (van or pickup required) • Weight (2-4 people required) • Gentle berm slopes required, >3:1 • Limited reach (five meters)
Future Research • Reduce size and weight • Evaluate and improve internal air profiles • Study effect of flow rate on emission
Conclusions Good comparative measurements of gas and odor emission rates
Conclusions Low sampling variance
Conclusions Lower detection limit: 500-1000 ppm n-butanol.
Conclusions Lower limit reached with properly designed swine lagoon “Low odor” lagoon 0.16% solids
Conclusions Odor emission rate increased for 1000-20,000 ppm n-butanol hood5-7
Acknowledgements • Purdue University Agricultural Research Program • State of Indiana Value Added Research Program • Ramco Sales, Inc.
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