Experiment And Application Research On Surfactant Optimization Of Coal Dust In Huangyuchuan Coal Preparation Plant

The coal dust pollution in the preparation workshop of Huangyuchuan Coal Preparation Plant is serious,the total dust concentration in many dust-producing points exceeds 100mg·m^-3,and the respirable dust concentration exceeds 50mg·m^-3.The existing spray dust reduction measures are difficult to meet the coal dust concentration required by the national standard,especially the control measures for respirable dust are not in place.When spraying dust,surfactant as an additive can increase the wettability of water to coal dust,and can significantly improve the dust reduction efficiency of respirable dust.Therefore,in this paper,aiming at the coal dust pollution problem in Huangyuchuan Coal Preparation Plant,the experiment of the optimal combination of dust suppressants suitable for spray dust reduction measures and the field application of dust suppressants are carried out.Based on the strong hydrophobicity of coal dust in Huangyuchuan Coal Preparation Plant,the experiment was carried out to optimize the combination of dust suppressants for five experimental parameters:surface tension,contact angle,settling time,spray particle size,and spray dust reduction efficiency.And the optimized dust suppressant was applied in Huangyuchuan Coal Preparation Plant for on-site dust reduction application.First,the surfactant monomer preference is performed.19 different types of surfactants were initially selected,and the surface tension,contact angle and settling time of the primary surfactants at different concentrations were determined.The surfactant compound experiment was carried out with 10 kinds of surfactant monomers with the critical micelle concentration lower than 0.05%,the surface tension lower than 30 m N/m and the ability to significantly improve the wettability of the solution to coal dust.Secondly,the surfactant compounding is preferred.The 10 preferred monomers were compounded in pairs,and the surface tension and contact angle of the compounded solution were measured.The experimental results show that the compatibility between anionic and nonionic surfactants is good in improving surface activity,and the compatibility between nonionics is good in improving wettability.On the basis of the preferred combination of surfactants,1%inorganic salts（Ga SO₄,Na₂SO₄,Ga Cl₂,Na Cl）were added to conduct the optimal experiment of contact angle and surface tension.The results show that Ga Cl₂has synergistic effect on the three surfactant compounding schemes.Concentration orthogonal tests were carried out on the three compound schemes and the inorganic salt Ga Cl₂,and the dust suppressant formulas of the three schemes were obtained.The spray particle size measurement and spray dust reduction experiment were carried out on the optimal plan,and the dust suppressant formula with the smallest spray particle size and the best dust reduction efficiency was obtained:0.06%AES,0.04%SAS-60,0.08%Ga Cl₂.Finally,the field application of the dust suppressant is carried out.The optimized scheme was applied to the supersonic water-drawing siphon pneumatic atomization dust control system of Huangyuchuan Coal Preparation Plant,and the coal dust concentration at the three dust-generating points of the blanking port,the tail of the belt conveyor and the transfer point of the conveyor belt was significantly reduced..Field application results confirmed that the prepared dust suppressant significantly improved the existing dust reduction efficiency of Huangyuchuan Coal Preparation Plant,and the coal dust concentration could be reduced to below the national standard after spray dust reduction.The dust suppression efficiency of the prepared dust suppressant（0.06%AES,0.04%SAS-60,0.08%Ga Cl₂）was 13-24%higher than that of clean water,and the dust-reducing efficiency of respiratory dust was 22-31%higher than that of clean water,and the application effect was good.