Numerical Simulation On The Removal Efficiency Of Dust And Liquid Droplet In WESP

WESP is a new and efficient equipment for the purification and treatment of flue gas. It not only can effectively remove fine particles but also has lots of advantages, such as low resistance, wide range of application and dealing with compound pollutants. Therefore, with the environment pollution pricking up, WESP has been more widely used in industry. With the development of computer technology and the application of numerical simulation technique, it is possible to make mathematical model for solving the ESP more accurately and display the results intuitively. Using numerical simulation technique for ESP research and analysis has become an important auxiliary method to design, evaluate and research ESP. this paper builds the mathematic physical model of the process of removing dust and droplet-particle in the WESP by using FLUENT, and study the influence of various factors on the efficiency of WESP.On the basis of in-depth analysis on electrostatic dust precipitator and mechanism, this paper did a systematic research on the application of FLUENT software in WESP, and built the governing equations and constructed the boundary conditions for the software. The governing equations include continuity equation of gas, gas momentum equation, particle dynamic equation, electric field equation and electric current continuity equation, etc. This paper argues that the flue gas is gas-solid two-phase flow in the WESP. Gas belongs to the continuous phase, using the Euler method to make numerical simulation of gas. Turbulence model adopts RNG k-ε turbulence model which is widely used in engineering. Particles phase is calculated by the discrete phase model. The results of numerical will be displayed graphically and intuitively. We get the trajectory and collection efficiency of dust and droplet-particle in different working conditions.Collection efficiency is the most important technical parameters of WESP. This paper systematically studied the influences of the properties of flue gas (including particle size and relative humidity), the electrode voltage, the inlet air flow rate, and the structural parameters of WESP (including Corona line space, length and space of collection plate) on the collection efficiency of WESP. Finally, the results shows that the relationship between different factors and the collection efficiency of WESP is as follows:Collection efficiency is increasing with the increase of particle size (0.1～7μm), voltage of the electrode (40-80kV), the length of collection plate (0.8～1.6m), and space of collection plate and relative humidity (0.2～1), but decreased with the increase of the inlet gas flow rate (0.5～2m/s), the space between wire and plate (0.1～0.25m), the length between the adjacent corona wire (0.1-0.5m), Under the same conditions, collection efficiency of the droplets is higher than that of dust particles, and droplet particles are more sensitive to the change of working condition.