Study On The Key Technology Of The Atomization Dust Suppression Of Wetting Agent In Heading Workface

Coal dust forms one of the five major natural disasters in coal mines. It not only seriously affects the safety of production in coal mines, but also threats the mine workers’ health. With the improvement of the mechanized mining efficiency in heading workface, the harm of high concentration of dust in the roadway is becoming more and more serious. The existing dust suppression technology in heading workface is mainly physical method, and ineffective on hydrophobic coal dust suppression. In recent years, the development of dust suppression technology by adding chemical wetting agent to water can enhance the water wettability for coal dust, thus improve the dust fall efficiency. But there are still many deficiencies in the existing research results. Therefore, this paper studied the key technology of the atomization dust suppression of wetting agent for heading workface, and focused on the optimization of the efficient compound wetting agent for dust control and the device for adding wetting agent. The paper provides a technical support for the further application of atomization dust control technology of wetting agent.The paper analyzed the theory of atomization, the principle of spray dust suppression and characteristics of surfactants. The reason of water added wetting agent improving the efficiency of the spray dust control was given out. Surfactant, the main component of wetting agent, can reduce the surface tension of water, enhance the effect of atomization and the efficiency of dust particle collection; With the water’s surface tension lowered, the resistance decreased in the process of the collision between dust particle and droplet and the dust is easier to penetrate the liquid film. Due to the special molecular structure of the surfactant, it can change the chemical composition of the coal dust surface and make the dust easy to be wetted by droplet, thus the dust fall efficiency is improved. The research results provide a theoretical basis for the optimization of compound wetting agent.In view of the disadvantages of the current wetting agent’s single component and poor dust fall effect. Based on the wettability of different coal dust, the surface tension, contact angle and coal dust sedimentation experiments were carried out and an optimum mixture of wetting agent was obtained. Through a spray dust fall experiment in a laboratory simulating roadway, the dust fall efficiency of the the mixture of wetting agent acting on different coal dust was measured. Experimental results show that the coal dust reduction efficiency of the mixture of wetting agent acting on all kinds of coal dust has been greatly improved. The dust fall effect is prominent, especially for strong hydrophobic coal dust. The rationality of the compound scheme was verified. The research results provide an optimization scheme of efficient compound wetting agent for dust control.Aiming at the deficiencies of the existing wetting agent adding technology, an adjustable concentration of wetting agent adding device applied in coal mine underground was put forward. The device does not need electric drive, and relies on the static pressure of mine water as a driving force. The adding concentration is stable and easy to adjust. Based on the heading workface, an atomization dust control of wetting agent system was arranged. The 3-D model of the adding device was established, the working characteristic theory model of adding device was set up, the principle of concentration regulation was explained, and the structure of the cylinder block was optimized by static simulation using the finite element analysis software Ansys.The reversing mechanism is a key element to the adding device. By using Adams software for dynamics simulation, the reversing mechanism was optimized. The dynamic characteristics of the reversing mechanism were analyzed under different length of the driven rocker arm. The results show that a smaller rocker arm length( l=17 mm) can meet the requirements of the spool movement, the force between body parts is smaller and the force after reversing is also stable. The simulation results provide a basis for trial-manufacture of physical prototyping and betterment design.