Experimental Study On Influence Of Imidazole Ionic Liquid On Wettability Of Coal

The coal seam water injection technology can pre-wet the coal body from the source,but due to the hydrophobic characteristics of the coal body,the wetting effect of the coal seam water injection liquid is not expected.In order to solve this problem,scholars usually add wetting agent to the solution to reduce the surface tension of the solution and improve the ability of the solution to moisten the coal body.The imidazole ionic liquid in the ionic liquid can reduce the surface tension of the aqueous solution,and compared with most of the traditional chemical reagent,it can significantly change the physical and chemical structure of the coal and improve the hydrophilicity of the coal.However,the study on the wettability of the imidazole ionic liquid to coal is relatively shallow,and it is still in the experimental stage in the laboratory and has not been applied in the field.Therefore,it is necessary to study the characteristics of imidazole ionic liquid wetting coal in a more systematic way to provide theoretical guidance for the field application of coal mine.Based on this,this paper analyzes the influence of 10 kinds of imidazole ionic liquid aqueous solution on coal wetting.The surface tension and contact angle of imidazole ionic liquid aqueous solution were studied.The influence of imidazole ionic liquid on the wettability of aqueous solution was analyzed.It is found that the imidazole ionic liquid anions are the same,the longer the side chain of imidazole cation is,the stronger the ability of water solution to wet coal is.The imidazole cation is the same,the wettability of the ionic liquid aqueous solution containing Cl^-is always stronger than that containing Br^-.The improvement of the wettability of BF₄^-on the ionic liquid aqueous solution is more significant with the increase of the imidazole cation side chain.When the side chain is short,the wettability of the ionic liquid solution containing BF₄^-is weaker than that of the ionic liquid solution containing Cl^-or Br^-;when the side chain is long,the wettability of the ionic liquid solution containing BF₄^-is stronger than that of the ionic liquid solution containing Cl^-or Br^-.The contact angle,functional groups and surface morphology of coal samples modified by imidazole ionic liquids were studied,and it was found that imidazole ionic liquids can change the proportion of some functional groups on the coal surface and increase the roughness of the coal surface,and improve the coal sample to a certain extent.Hydrophilic.The cation is the same,and the effect of anion on improving the hydrophilicity of ionic liquid modified coal is:Cl^->Br^->BF₄^-.The anion contained is Cl^-or Br^-:[BMIM]⁺>[EMIM]⁺>[HMIM]⁺;the anion contained is BF₄^-:[BMIM]⁺>[HMIM]⁺>[EMIM]⁺>[C₈MIM]⁺.That is,the coal sample treated with ionic liquid[BMIM][Cl]is the most hydrophilic.As the immersion time of imidazole ionic liquid increases,more pores and cracks begin to appear on the surface of coal particles,and the cracks gradually become deeper and wider until the coal particles are broken into several small coal particles,which leads to the improvement of the hydrophilicity of the modified coal first.After that,it decreases,but it is easier to be wetted by aqueous solution compared with clean water modified coal.Imidazole ionic liquid can obviously reduce the surface tension of aqueous solution and improve the hydrophilicity of coal.It is found that the imidazole ionic liquid can reduce the amount of coal dust produced in the process of coal crushing through the experiment of gravitational falling weight dust production.It is theoretically proved that the imidazole ionic liquid can improve the effect of water injection to moisten the coal body and reduce the amount of coal dust produced in the process of coal mining.Figure 55 Table 12 parameter 115...