Using water-soluble polymer solution to inhibit clay swelling

Using water-soluble polymer solution to inhibit clay swelling Yang Hong, Sun Jianrong, Li Yingquan (Beijing Zhongmei Mining Engineering Co., Ltd., Beijing 100013, China) Determination of clay swelling quantity, exploratory experiment of inhibiting clay swelling by polymer solution was conducted.

1 Causes of Clay Expansion The reason for the failure of clay layered structures is the hydration of clay caused by the water entering the clay due to the physical and chemical adsorption of water or ions at the water-clay interface. The hydration effect changes the strength, density and charge properties of the clay, and appears macroscopically as expansion. The extent of the change is related to the composition, structure, hydrophilicity, specific surface, porosity, and saturation of the clay. The water composition of the contact and the conditions (temperature, pressure), etc., that the clay and the water are in contact with each other. There are two kinds of clay hydration mechanism: permeation hydration. When the concentration of cations adsorbed on the surface of the clay is higher than that in the medium, osmotic pressure is generated, which causes the water to diffuse into the intercrystalline layers of the clay. This degree of diffusion of the water is controlled by the concentration difference of the electrolyte. The volume increase due to permeation hydration increases the specific crystallinity. The designed air volume is 6m3/s, and the level of moving blades is adjustable. The blade angle changes in the range of 20 to 3 s, and the maximum power ratio of the two stages is 1.07 to 1.68, which is quite large. The iv-stage impeller requires only 18 kW motors, while the step-by-step motors require 30 kW motors. The power characteristics of the actual fan confirmed the conclusion of the theoretical analysis.

34 Countermeasures Against Motor Overloading Excessive power ratios can easily cause overload of the class motor. To prevent overload, consider two approaches. First, according to equation (10), the relative velocity flow angle B22 of the stage moving blade outlet is appropriately reduced. This practice is no longer designed strictly according to the principle of equal wind pressure, and reduces the power ratio by reducing the stage load. The conventional design method determines the motor capacity. The second is to use formula (9) to calculate the maximum power N2max of the stage, and determine the capacity of the stage motor accordingly. The i-class motor can be connected with the real impeller inside and the inside of the impeller without the loss of airflow in the impeller. The flow state has a large difference, but the power variation ratios of the two are similar, so the calculation results of the theoretical model have a certain value. Determining the motor capacity in this way can avoid blindness and reduce prototype test workload.

4 Conclusion According to the theoretical model, the wind pressure characteristics and power characteristics of the counter-rotating fan are analyzed. There is a big difference in the wind pressure of the i-staged moving blade, which is the cause of the large class power. The formula for calculating the maximum theoretical power ratio of the two stages is obtained. The maximum theoretical power ratio depends on the relative velocity flow angle at the i and the stage outlet. The design condition has a certain amount of air flow, and the maximum power ratio decreases with the increase of the total wind pressure. In order to prevent the overload of the stage motor, the method of determining the motor capacity according to the maximum power of the stage is proposed and can be designed.