| Gas drainage is a fundamental measure for coal mine gas disasters.The gas drainage water ring vacuum pump has a simple structure and can compress the gas isothermally.It can safely and reliably transport flammable,explosive,dusty and water-containing gas.Therefore,it is widely used in coal mine gas drainage.However,the high power consumption of gas drainage pumps is a shortcoming that cannot be ignored.The use of polymer drag reduction solution to save energy and improve efficiency of gas drainage pumps has solved this problem to a great extent.In the engineering application of energy-saving technology,solid particles such as pulverized coal carried in the gas enter the drag reduction solution of the gas drainage pump,which has a negative impact on the energy-saving effect.Therefore,studying the relationship between the pulverized coal solid particles and the polymer drag reduction solution is of great significance to the energy saving and consumption reduction of the gas drainage system.This paper uses a self-built experimental platform of a small gas extraction pump unit to experimentally study the relationship between the concentration and particle size of the pulverized coal and the operation performance of the pump unit.At the same time,the MCR102 rheometer was used to test the rheological properties of the drag reduction solution before and after the addition of pulverized coal and the increase in running time.(1)According to the test results of the water samples of the gas pumping station at the project site,the particle size and concentration of the experimental pulverized coal were determined.The particle size distributions of three experimental pulverized coal samples were measured,and the median particle size D50 was 20.13?m,97.89?m and192.86?m,respectively.The influence of pulverized coal concentration on the performance of gas drainage pumps is studied:for three commonly used concentrations of drag reduction solutions,as the concentration of pulverized coal increases,the operating power of the pumping pump increases and the energy saving rate decreases.It shows that the greater the concentration of pulverized coal,the greater the negative impact on the energy saving effect of the drag reduction solution.Comparing the relative energy saving rate of the drag reducing solution,it is found that the shear resistance of the 3000ppm and 4000ppm drag reducing solutions is better than that of the 2000ppm solution.Affected by the change of resistance loss and the destruction of the internal network structure of the solution,the influence of pulverized coal particle size on the energy saving effect is different due to the difference in the concentration of the drag reduction solution:for the 2000ppm solution,the smaller particle size pulverized coal has a greater impact on the energy saving effect;for the 3000ppm solution,there is no obvious difference between different particle sizes;for 4000ppm solution,larger particle size pulverized coal has a greater impact.(2)The changes in the rheological properties of the drag reduction solution before and after the addition of pulverized coal are studied:for the three commonly used concentrations of drag reduction solutions,the viscosity of the drag reduction solution increases after the addition of pulverized coal.And with the increase of the concentration of pulverized coal,the viscosity of the drag reduction solution shows a rapid increase first,then decreases the increasing speed,and finally tends to be stable.In the angular frequency range of 0.1?10rad/s,the viscoelastic modulus increases after pulverized coal is added.The relationship between running time and rheological properties is analyzed:the drag reduction solution samples all show the shear thinning characteristics of pseudoplastic fluid.As the running time increases,the shear stress and shear viscosity are gradually reduced,and the viscoelasticity the modulus is gradually reduced.The shear resistance of 4000ppm drag reducing solution is stronger than that of 3000ppm and 2000ppm solutions.The concentration of pulverized coal has a greater impact on the viscoelasticity of the drag reduction solution than the particle size of the pulverized coal.The greater the concentration of pulverized coal,the greater the effect on the viscoelasticity of the same drag reduction solution,and the lesser the effect of pulverized coal on the viscoelasticity of the concentration of the high-concentration drag reduction solution.(3)Taking the concentration of pulverized coal and the particle size of pulverized coal as the key factors,the influence law on the energy saving effect of the drag reduction solution was studied,and the rheological properties of the drag reduction solution before and after the addition of pulverized coal were compared.The energy-saving effect has a greater impact than the particle size of pulverized coal.The sensitivity of the drag reduction solution to the pulverized coal is analyzed,which provides an important data reference for the selection of the pulverized coal filter device in the energy-saving and efficiency-increasing system of the gas drainage pump.(4)The Yuwu coal mine 2#gas extraction pump system was transformed.According to the analysis of pulverized coal concentration and particle size and energy saving effect,the DL-3P2S pulverized coal filter with self-cleaning function was selected.The field experiment compared the difference before and after installing the pulverized coal filter device.After the 2000ppm,3000ppm and 4000ppm solutions are filtered by pulverized coal,the energy-saving rate is increased by 1.57%,2.66%and1.10%respectively.Calculated with the optimal performance concentration of3000ppm,the annual power consumption of the energy-saving system without the pulverized coal filter will be reduced by about 1.296 million k W·h,and the annual power consumption will be reduced by about 1.445 million k W·h after the installation of the pulverized coal filter.This article has 42 diagrams,13 tables,and 66 references. |
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