Evaluating of the performance of a composite wetting dust suppressant on lignite dust

The traditional method of suppressing dust by spraying water is not effective for lignite owing to its hydrophobic characteristics. Thus, an effective composite wetting dust suppressant was designed to improve the suppressive efficiency of this method. In this study, proximate analysis and Fourier-transform infrared spectroscopy (FTIR) were conducted for lignite dust. The wetting ability of the surfactants, the atomization performance of droplets, as well as the effect of inorganic salt on the water evaporation rate, were also investigated. The effective composition of the dust suppressant was confirmed by simulating the spraying suppression process and conducting an experiment for industrial application. The results show that lignite has strong hydrophobic properties owing to its chemical properties and surface morphology. The wetting ability of the surfactants is shown to depend on the surface tension and chemical structure of the surfactants. The addition of surfactant could obviously reduce the diameter and increase the axial velocity of droplet. The evaporation rate was reduced after adding hydrating inorganic salt without affecting the surface tension. By adding a composite wetting dust suppressant with a composition of 0.1%T-1 and 0.9% CaCl2 , the total dust removal efficiency of the simulated spraying suppression system was improved from 75.11% to 96.73%, and the mass concentration of fine lignite particles was decreased from 83.37 to 15.153 mg/m(3) . The results of the industrial application experiment show that the mass concentration of lignite dust was reduced from 747.2 to 21.3 mg/m(3) , and the suppression efficiency reached similar to 97.1%. (C) 2018 Elsevier B.V. All rights reserved.