Research On Discrete Foam Suppressing Coal Dust Technology

It is well known that dust not only makes people susceptible to pneumoconiosis,but also causes dust explosion when certain conditions are met.At present,most of the foam dust removal technology used in mines is the overburden type,which mainly aims at local area dust removal,and the effect is not good for the area with wide dust producing area.By referring to the research results at home and abroad,this paper puts forward a new technology of discrete foam dedusting,which has the advantages of wide dedusting area and high dedusting efficiency.Based on this,the formation mechanism of discrete foam,the dust removal mechanism of foam and the factors affecting the wettability of coal dust were firstly studied in this paper.Then,according to the research results,the surfactant was screened and the foam was prepared.Finally,the discrete foam dust removal experiment was carried out based on the experimental platform.The main conclusions are as follows:(1)Based on the foam formation mechanism and foam dust removal mechanism,it is shown that the formation of foam needs three conditions:(1)the surface tension is lower than the critical value;(2)continuous gas-liquid contact;(3)Long life span.Foam dust removal mainly includes interception effect,collision effect,wetting effect,diffusion effect and adhesion effect.(2)Through elemental analysis,scanning electron microscopy,infrared spectrum and sedimentation experiment results,it is concluded that: With the increase of coalification degree,the content of carbon element increases,the coal dust porosity decreases,and the hydrophilicity of coal becomes worse.The hydrophilicity of coal dust is improved after it is soaked by surfactant.The wettability of coal varies greatly with different kinds and concentrations of surfactants.(3)By testing the foaming volume,defoaming volume and sedimentation rate of single reagent and compound reagent,three kinds of surfactants were selected as the main components of the foam solution.The order and concentration of the three surfactants were determined by orthogonal experiment.The type and concentration of foam stabilizer were determined by adding three kinds of inorganic salts with 0.2%-1% concentration.The best formula for water retention was determined by adding 0.3-1.2% glycerin.(4)The simulation experiment was carried out using the platform: Through the experiment of natural settling of coal dust,it is concluded that the greater the mass of coal dust,the longer the natural settling time.Through the foam dust removal experiment,it is concluded that the dust removal time using the foam dust removal is far lower than the natural settling time.The effectiveness of the foam and the high efficiency of foam dust removal were verified by simulating the working face with continuous coal dust generation.