Study on properties of laser-induced coal particle flow plasma with different laser parameters

Laser-Induced Breakdown Spectroscopy (LIBS) was used to detect the components of coal particle flow. The influences of different parameters of laser on the plasma characteristics of coal particle flow were studied. The parameters included different laser wavelengths and laser energies. The coal commonly used in the power plants in China was chosen as the experimental sample. Before the experiment, the diameter of coal particle was less than 0.2 mm by sieving method. Then the experiment was carried out at different laser wavelengths and laser energy. The results show that the variations trends of the plasma temperature, electron density and the lines intensity with laser energy are consistent under different laser wavelengths. However, as the laser energy increases, these characteristic parameters increase faster under 1 064 nm than that under 532 nm. The main reason is that the short wavelength (532 nm) with higher photon efficiency would reach the saturated state under lower laser energy.