Particulate matter reduction in exhaust gas from poultry keepings
In extensive test runs, the particulate matter reduction of different scrubbers for poultry exhaust air cleaning was investigated with aerosol spectrometers. The attainable particulate matter reduction depended on treatment setup and kind of the water distribution systems which may produce water aerosols and partially result in negative separation efficiencies at particle size diameters < 2.5 μm. At particle size diameters of 2.5–3.0 μm, the mean separation efficiency varied between 5.6 and 73.1% among the experimental plants. The separation efficiency generally increased with the particle size and varied between 56.4 and 97.6% at particle diameters of 6.5–7.5 μm. A constant positive particulate matter reduction over all particle sizes was only achieved using water distribution systems with a low operating pressure of 0.1–0.2 bar. The highest separation results among the scrubber systems were achieved in combination with a dry working dedusting unit. In comparison to the experimental plants with scrubbing units, the dry working electrostatic precipitator consistently showed higher particle separation efficiencies, even with shorter residence times. Especially at particle sizes < 3 μm, the dry working electrostatic precipitator outmatched all the scrubber systems.