煤层注射成胶型抑尘剂影响因素及抑尘效果研究

Study on influencing factors and dust suppression effect of coal seam injection gum-forming dust suppressant

为解决煤层注水降抑尘技术中水分易流失,开采时注水抑尘效果较差等问题,提出一种既能增加煤层保水率又能改善煤层脆性的抑尘方法:研制出以海藻酸钠(SA)为基质的成胶型抑尘剂,并开展比表面积试验、氮气吸附试验、扫描电镜试验和产尘率试验,研究表面活性剂、黏度及注射压力对成胶型抑尘剂的影响。结果表明:表面活性剂有利于煤层润湿,但对抑尘效果影响较小;抑尘剂黏度增大有利于保水,可使保水时间由10 h提升至30 h,但会导致材料难以进入煤层内部;注射压力对于抑尘剂的抑尘效果具有较大影响,当煤层注射压力较小时,抑尘剂难以快速渗入煤的内部孔隙中,随着压力的增大,抑尘剂逐渐渗入煤孔隙中。当注射压力升至3 MPa后,抑尘效果不再随压力的增加而增加,产尘率由4%降低至2.3%,相对降幅达50%,有效降低了产尘。

In order to solve the problems of easy water loss and poor dust suppression effect in coal seam water injection technology,a dust suppression method which can not only increase the water retention rate of coal seam but also improve the brittleness of coal seam was proposed.A gum-forming dust suppressant based on sodium alginate(SA)was developed.The effects of surfactant,viscosity and injection pressure on the gum-forming dust suppressant were tested by means of specific surface area test,nitrogen adsorption test,scanning electron microscope test and dust production rate test.The test results show that the surfactant is beneficial to the wetting of the coal seam,but has little effect on the dust suppression.The increase of the viscosity of the dust suppressant is conducive to water retention,which can increase the water retention time from 10 h to 30 h,but it will make it difficult for the material to enter the coal seam.The injection pressure has a great influence on the dust suppression effect of the dust suppressant.When the coal seam injection pressure is small,the dust suppressant is difficult to quickly penetrate into the internal pores of the coal.With the increase of pressure,the dust suppressant gradually penetrates into the coal pores.When the injection pressure rises to 3 MPa,the dust suppression effect no longer increases with the increase of pressure,and the dust production rate is reduced from 4%to 2.3%,which is relatively decreased by 50%,effectively reducing the dust production.