tailieunhanh - AIR POLLUTION CONTROL TECHNOLOGY FACT SHEET

The major sources of carbon monoxide pollution are automotive exhaust and emissions from large industrial combustion sources such as electrical power plants. Because these sources produce many contaminants in addition to carbon monoxide -- such as fine particles and nitrogen oxides -- it is often difficult to isolate the health effects of ambient carbon monoxide from those of other pollutants. In addition to carbon monoxide generated outside, there are also important indoor sources of the pollutant. The most important of these are combustion sources such as gas ovens, gas burners, water heaters, and heating systems. However,. | EPA-452 F-03-005 Air Pollution Control Technology Fact Sheet Name of Technology Cyclones This type of technology is a part of the group of air pollution controls collectively referred to as precleaners because they are oftentimes used to reduce the inlet loading of particulate matter PM to downstream collection devices by removing larger abrasive particles. Cyclones are also referred to as cyclone collectors cyclone separators centrifugal separators and inertial separators. In applications where many small cyclones are operating in parallel the entire system is called a multiple tube cyclone multicyclone or multiclone. Type of Technology Removal of PM by centrifugal and inertial forces induced by forcing particulate-laden gas to change direction. Applicable Pollutants Cyclones are used to control PM and primarily PM greater than 10 micrometers pm in aerodynamic diameter. However there are high efficiency cyclones designed to be effective for PM less than or equal to 10 pm and less than or equal to pm in aerodynamic diameter PM10 and PM2 5 . Although cyclones may be used to collect particles larger than 200 pm gravity settling chambers or simple momentum separators are usually satisfactory and less subject to abrasion Wark 1981 Perry 1984 . Achievable Emission Limits Reductions The collection efficiency of cyclones varies as a function of particle size and cyclone design. Cyclone efficiency generally increases with 1 particle size and or density 2 inlet duct velocity 3 cyclone body length 4 number of gas revolutions in the cyclone 5 ratio of cyclone body diameter to gas exit diameter 6 dust loading and 7 smoothness of the cyclone inner wall. Cyclone efficiency will decrease with increases in 1 gas viscosity 2 body diameter 3 gas exit diameter 4 gas inlet duct area and 5 gas density. A common factor contributing to decreased control efficiencies in cyclones is leakage of air into the dust outlet EPA 1998 . Control efficiency ranges for single cyclones are often .