The goal of this research was to increase performance of small coal dust particles captured by electrical charged water spray compared with that by water spray only. A testing model for particle capture was constructed by electrical charged water spray. Particles used in the test were talc powder that is represented coal powder. The capture efficiency could be evaluated form the weights of the air filter before and after the test. The first experimental case was performed in a test room with dimensions of 3 m height x 2 m width x 2 m length. The capture efficiency by electrical charged water spray was done with 5 kV high voltages and the water flow rate of 3.22 ml/s. The second experiment case was performed in a horizontal wind tunnel for studying influence of air velocity effect on particle capture. Three methods, no water spray, water spray, and electrical charged water spray, were carried out. To protect electrical breakdown, the appropriate electrode ring diameter with a wire having a radius of 0.05 cm was 4 cm with a distance 2.2 cm from the nozzle. From the first experiment, it was found that, the capture efficiency increased with the increased time of water spraying. For the second experiment, while the range of air velocity was 0.1-0.3 m/s with electrical charging, the capture efficiency increased about 35%. In addition, while the range of air velocity was 0.3-1 m/s, the capture efficiency of electrical charged water spray was reduced and close to that with no electrical charged condition. However, the capture efficiency of the electrical charging condition was about 20% higher on average.
Keywords
Electrical charged water spray, Capture efficiency, Air velocity, Ring-axis electrode