Study On The Ratio Of Bentonite Composite Resistance Reducing Agent And Its Corrosiveness And Durability

The grounding accidents of the power system occur frequently in the areas of high soil resistivity.To solve this problem,the most commonly used construction method is to lay resistance reducing agent around the grounding grid to play a role in reducing resistance and corrosion of the grounding body.It has been tested that the resistivity and corrosion inhibition of most of the drag reducing agents have not reached the relevant standards.Therefore,this paper has prepared a long-acting sodium-based bentonite composite drag reduction to achieve the effects of low resistivity,high water retention and good corrosion resistance by adding conductive particles,water retention agents,buffers and corrosion inhibitors to the sodium-based bentonite.The main research contents are as follows:According to the characteristics of low intrinsic resistivity of sodium-based bentonite,sodium-based bentonite is used as the matrix,and different amounts of carbon-based conductive particles are combined with sodium-based bentonite to improve its conductivity.The main test standards are resistivity and water absorption.The results of the test show that the addition of carbon-based conductive particles to sodium-based bentonite can reduce the water absorption of the material.The resistivity of the composite resistance-reducing agent first decreases slowly with the increase of carbon-based conductive particles,and then after a sharp drop to the percolation threshold,the resistivity tends to be flat.Between different conductive particles,the drag reduction effect will have a synergistic effect Finally,the selection of graphite infiltration threshold of 8%and carbon nanotube infiltration threshold of 12%is determined as conductive particles.The water content in the sodium-based bentonite directly affects the drag reduction and anticorrosion effect.The test results show that the optimal moisture content of the composite drag reduction agent construction is 65%,corresponding to the water absorption rate of 33.66g/g,which can evenly disperse the conductive particles,buffers,corrosion inhibitors,etc.,and absorb water to expand and tightly wrap the grounding body.Polyacrylamide is added into the composite drag reducing agent to increase the water retention,form a group between particles,thus forming cross-link into a network to resist soil erosion.Water retention agent Glauber's salt is also added to increase the water retention of the composite material.And finally,the amounts of polyacrylamide and Glauber's salt are determined as 10%and 5%respectively through orthogonal experiments.In sodium-based bentonite,4%ammonium chloride coated with activated carbon is added as a buffering agent.The composite drag reducing agent is weakly alkaline and has a good corrosion inhibition effect.The pH value is 9.00.Considering the economic effect and environmental protection comprehensively,sodium molybdate is selected as the corrosion inhibitor.A dense protective film formed on the surface of the carbon steel test piece is found to effectively prevent corrosion during the experiment.The corrosion rate can be effectively reduced when the content of 4%is used.The corrosion rate is 0.133mm/a in the accelerated environment.The main indicators of the developed sodium bentonite composite resistance reducer are in line with the relevant national indicators.