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Tham khảo tài liệu 'air pollution control systems for boiler and incinerators part 5', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | TM 5-815-1 AFR 19-6 a. THEORETICAL FRACTIONAL EFFICIENCY CURVE 100 THEORETICAL EFFICIENCY CURVE _ VciENCY CURVE o s UJ tn a U UJ UJ N n ZONE EDDY ZONE OF riCLE INCREASING COLLISIONS a OF DECREASED EFFICIENCY DUE TO FLOWS AND particle bouncing EFFICIENCY DUE TO FLOCCULATION EFFECTS o 8 0 INCREASING PARTICLE SIZE b. TYPICAL MANUFACTURER S FRACTIONAL EFFICIENCY CURVE U.S. Army Corps of Engineers Figure 6-9. Fractional efficiency curves 6-11 TM 5-815-1 AFR 19-6 U.S. Ariby Corps of Engineers F igure 6-10. Effect of smaller cyclones in parallel on theoretical cyclone collection efficiency particles they are usually designed for low inlet velocities 5-10 feet per second ft sec . This is done to minimize erosion on the cyclone walls and to minimize breakdown of coarser particles that would normally be separated into particles too fine for collection. e. Limited space. In cases where cyclones must be erected in limited space smaller diameter multicyclones have an obvious space advantage over larger diameter units. Small cyclones also have the advantage of increased efficiency over a single unit handling the same gas capacity although this advantage is sometimes lost by uneven gas distribution to each unit with resultant fouling of some elements. 6-6. Cyclone performance a. Collection efficiency and pressure drop. For any given cyclone it is desirable to have as high a collection efficiency and as low a pressure drop as possible. Unfortunately changes in design or operating variables which tend to increase collection efficiency also tend to increase pressure drop at a greater rate than the collection efficiency. Efficiency will increase with an increase in particle size particle density gas inlet velocity cyclone body or cone length and the ratio of body diameter to gas outlet diameter. Decreased efficiency is caused by an increase in gas viscosity gas density cyclone diameter gas outlet diameter and inlet widths or area. The effect on theoretical collection efficiency of
