Design And Improvement Of The Jet-mixing Nozzle Used In Chlorosulfonated Polyethylene Emulsion Devolatilization

Chlorosulfonated polyethylene (CSM) is an useful special rubber. Currently the main production process used is wet process with carbon tetrachloride (CCl4)as solvent. In the process,it is difficult to make CSM emulsion uniformly distributed in the condensation pot, the percent recovery of CCl4 is low. Not only the CSM product quality is poor, but also CCI4 can make severe damage to the ozone layer. Therefore, The study on the application of jet stream to the CSM demulsification and devolatilization is meaningful. In this paper, a jet-mixing nozzle was designed and an experimental device for lab tests was set up. The influence factors of CSM devolatilization were analyed both through experiments and Fluent software numerical simulation. The analysis and experiment results are as followings.(1) Water jet can be used in CSM demulsification and devolatilization process. CSM emulsion can be quickly broke and dispersed with the shear and compression of high-speed water, then condensed into small particles. It can increase relative surface area of CSM particles and provide a favorable condition for devolatilization and discharge of low volatile components (main component is CCl4).(2) The jet-mixing nozzle is a key part in CSM emulsion devolatilization process with a jet. CSM emulsion can be mixed with water on macro first, then on mesoscopic mixing, and finally micro-mixing. In these processes, CSM emulsion can be dispersed with high-speed water, then broke and condensate into small particles.(3) In the mixing process, the force between high-speed water and CSM emulsion is the key factor for the low volatile component of CSM products. CSM emulsion can have a higher strain rate when the force is larger, and the average diameter of particles becomes smaller, then the content of the low volatile component of CSM products becomes lower because the increasing of relatively surface area. There are three factors influence the force between high-speed water and CSM emulsion. They are velocity of water jet, incidence angle and diffuser angle of nozzle. In a certain range, the content of low volatile component in CSM emulsion decreases with the increase of the water velocity, incidence angle and diffuser angle of the nozzle, which is due to the increase of the force exerted on the CSM emulsion.