Flare emissions of air pollution
Air polluted with noxious gases, fumes and aerosols, even when it is removed by local suction devices are generally not cleaned before throwing it out. To avoid air pollution near the company removed the ventilation is usually set aside as possible to higher layers of the atmosphere.
Abstraction extracted from the air spaces in the upper atmosphere is especially important when a large specific weight removed pollutant, which cools the outside, have a tendency to fall. This trend to a large extent contribute to applied yet still umbrellas over the exhaust vent pipe. Contamination of harmful gases surface layers of the atmosphere of industrial site (these sections we are interested in) increases with no wind and the rain, snow, fog and frost.
Religion in the enterprise has a high tube (60-100 m) and if possible to vent exhaust fumes in this tube, the removal of contaminated air into the upper layers allowed easy. But mostly it's impossible. The device is the same for each ventilation system which discharge pipe height at least 40-60 m hardly realistic, since the amount of exhaust PA modern enterprises amounts to several hundred.
Removal of contaminated air into the upper atmosphere is most easily done using the so-called jet ejection.
Flare emissions based on the property leaving the nozzle of the jet - it РґР°Р»СЊРЅРѕР±РѕР№РЅРѕСЃС‚Рё.РљРѕРЅСЃС‚СЂСѓРєС‚РёРІРЅРѕРµ design flare emissions is simple. Instead of the usual hood exhaust pipe is provided with a smooth confuser n ends a cylindrical nozzle (Fig. 13). By reducing the cross-section exit velocity of air increases, respectively, which allows you to create long-range jet. In the particular case of a short and straight exhaust restriction can not do. Then the entire pipe will have a diameter Do, needed to create the flame.
In general, if the length of the diffuser nozzle must be at least 2,5 D0, as shown in Fig. 13.
Exit velocity of air from the nozzle varies widely: the higher the rate, the better ceteris paribus flare emission. Lower limit of the escape rate in the presence of gas hazards should be considered as 15-20 m / sec. In the absence of gaseous pollutant, ie, when to remove moisture, heat or dust (for dust, after appropriate treatment) may reduce the rate of the exhaust up to 10 m / sec. Upper speed limit should be considered as 40 m / sec, so as to further improve its cost disadvantage.