The Research Of Devolatilization Characteristics In High-Speed Reactor

In the process of polymer production, there will be many volatiles which have a smaller molecular weight in the product. The existence of these volatile components will affect the quality of our product, so these must be removed. High-speed reactor is a new devolatilization device with a rotor in the middle which can have a great shearing force to disperse the syrup so as to greatly improve the specific surface area. We operate the device in vacuum conditions to strengthen the mass transfer. So it’s very important for us to study the characteristics of flow and mass transfer.Flow characteristics:In this paper we use a stered microscope measuring diameter when studying the characteristics of flow and use a high-speed camera when studying the characteristics of flow for the speed. The experiment is operated under atmospheric pressure with the material of syrup. We select the rotational speed and radial distance as variable to study liquid silk diameter, resultant velocity, radial velocity, angular velocity, speed angle and liquid form to find residence time, specific surface area.etc. We can get the following conclusion through the experiment:(1) The diameter decreases with the increase of rotational speed at the same radial distance; The diameter decreases with the increase of radial distance at the same rotational speed and decreases less and less eventually stabilized. The final average diameter d is proportional to the speed N-0.6. (2) All of the resultant velocity, radial velocity, angular velocity decrease with the increase of rotational speed at the same radial distance, however speed angle increases. At the same rotational speed, resultant velocity has a small growth firstly with the increase of radial distance then diminishes gradually and the greater the rotational speed decreases the higher the speed is. The radial velocity increases with the increase of radial distance then flattens out, eventually decreases at the same rotational speed and we calculate the residence time and find it is inversely proportional to the speed. The angular velocity and speed angle decrease with the increase of radial distance at the same rotational speed. (3) We deduce the form of liquid silk and calculate the silk’s length, volume and specific surface area then we know that there is a linear relationship between the specific surface area and speed. At the same time we can also calculate the number of liquid silk by the rate of flow.mass transfer characteristics:In this paper we study the characteristics of mass transfer under the condition of vacuum with the material of syrup and use the acetone as volatile. We adopt orthogonal experiment and select the initial concentration (A), feed rate (B), absolute pressure (C) and rotational speed (D) as variable to study the efficiency of devolatilization. We can get the following conclusion through the experiment:(1) The order of influential factors is C-A-D-B in the range of experimental conditions by range analysis and the optimal combination is A1B2C1D5. We can get the same order by ANOVA, however, the optimal combination is A1B5C1D5. (2) The pressure plays a leading role in the process of devolatilization for the birth of bubbles.