ENGINEERING JOURNAL CHIANG MAI UNIVERSITY

Volume 27, No. 02, Month AUGUST, Year 2020, Pages 151 - 163

Control of coal particle dispersion over crusher by air curtain

Chanyagrid Jantapimpa and Attakorn Asanakham

Abstract Download PDF

The aim of this study was to control and reduce coal particle dispersion in a coal crusher basin model by air curtain. A set of air nozzles was installed at the edge of the tested basin having dimensions of 0.6 m width x 1.2 m length x 0.6 m height. The flow pattern and pressure drop of the flow field of the air in the basin due to the air curtain were evaluated by ESI-CFD program. Experiments to observe the coal particle dispersion and coal particle concentration were carried out. In the experiment, without the air curtain, 8.5 kg of coal having a size in a range of smaller than 0.045 mm to larger than 50.8 mm was dumped into the tested basin by a 30o inclined tray with a velocity of 5 m/s. It could be found that the amount of PM10 dispersed rapidly from 96.7 μg/m³ to the measured full scale of 1,999 μg/m³ around the basin side area and from 233.6 μg/m³ to the measured full scale of 1999 μg/m³ around the basin front area in the retention times of 9 and 6 seconds, respectively. With air curtain, to control the dispersed particles, the air velocity at around 35 m/s could control the dispersed particle pattern to be in the same direction as that of the air curtain and less particle amount spread out to the front area. The average amount of the particles was at around 166.22 μg/m³. The study with different velocities of the feeding coal particles at 2.5, 5 and 7.5 m/s on the air dynamic pressure that generated particle dispersions was also performed by ESI-CFD simulation. The dynamics pressures were found to be 12.3734, 28.4808 and 56.2321 N/m², respectively. Then the air curtain that generated the pressure drops between the air in the tested basin and the air over the curtain were 6, 20 and 41 N/m² at the air curtain velocities of 20, 35 and 40 m/s, respectively.

Keywords

Crusher, Air curtain, Control of coal particle dispersion, Computational fluid dynamics

---