Research On Application Of Rotating Super-Gravity Field To Purify Coal Mine Dust

A large amount of dust is produced in the coal mining and heading work face in the coal mine,especially the fine respiratory dust,which affects the air quality in the coal mine.Due to the small underground space and large gas flow,the application of mature large-scale dust removal equipment which used in the ground is limited.At present,the dust removal technology in the underground coal mine mainly adopts wet and dry method to remove dust.The wet method is used the water mist which is produced by combined high-pressure nozzles to collect coal dust.However,the wet method consumes a large number of water,and increases the air humidity in the coal mine.The dry method is used the filter cartridge or bag to remove the coal dust,but the equipment covers a large space,and the coal dust adhering the surface filter is not easy to fall off.The rotating super-gravity field is a new dust removal technology which is enhanced by external field.It has the advantages of high dust removal efficiency,small equipment volume and low pressure drop loss.It has been successfully applied to environmental protection and other fields.Combined with the physical and chemical characteristics of coal mine dust,the application of rotating super-gravity field collector which is self-made to purify coal mine dust has been studied in this paper.Firstly,the single factor method is used to study the effects of rotor speed,gas flow,initial dust concentration,dust particle diameter,water spray volume,the additive amount and dust concentration in washing water on the purification rate of simulated coal dust.Secondly,the comprehensive effects of rotating speed,water spray and gas flow on the purification of coal dust in rotating super-gravity field are further studied by using orthogonal experimental method.In this study,the rotor packing of the rotary super-gravity field dust collector is made of 316L stainless steel wire mesh,which is folded according to the design angle.The outer diameter of the rotor is 200mm,the inner diameter is 120mm,the thickness of the packing layer is 30mm and the length of the rotor is 300mm.The variable frequency motor is used as the rotor power,and the frequency converter is used to adjust the rotor speed.The simulated coal dust is prepared with pulverized coal of 70%(w/w)of 200 mesh(160 mesh sieve,200 mesh sieve residue),25%(w/w)of 600 mesh(500 mesh sieve residue,600 mesh sieve residue),and 5%(w/w)of 700 mesh(600 mesh sieve residue,700 mesh sieve residue),which is added to the spiral feeder for quantitative input into the air flow pipe.The results show that:(1)With the increasing of rotor speed,the dust concentration at the outlet of the collector decreases and the dust removal rate increases.The dust removal rate decreases with the increasing of gas flow.The initial dust concentration of inlet gas has no obvious effect on the dust removal rate.The dust removal rate decreases with the increasing of the weight of fine particles in the inlet gas,increases with the increasing of water spray volume.Under the experimental conditions,when the rotor speed is 800rpm,the water spray volume is 12L/min,the gas flow is 60m3/h and the initial dust concentration is 11 00mg/m3,the dust removal rate is greater than 90%.(2)It is found that adding anionic surfactant to the washing circulating water can effectively improve the wetting rate of coal dust,and the dust removal rate increases with the increasing of the amount of surfactant However,when the addition amount is greater than 0.4%,the increasing trend of removal rate gradually flattens.With the increasing of circulating water dust concentration,the change trend of rate is not obviously,indicating that the water dust concentration has little effect on dust removal rate.(3)The orthogonal experimental study shows that in the dust removal process of rotating super-gravity field collector,the order of the effects of rotor speed,gas flow and liquid spray volume on the coal dust removal rate is:rotor speed>gas flow>liquid spray volume.Under the optimum conditions,the maximum dust removal rate of coal mine dust can reach 98.2%.The results of this study can provide a theoretical basis for the application of rotating super-gravity field collector in the coal mine dust purification,and has application value and environmental protection significance.Figure[29]Table[14]Reference[66]...