| The new water-jet flow technology was applied to the demulsification and devolatilization of chlorosulfonated polyethylene geomembrane (CSM) latex condensate process to reduce the low volatile component (CCl4), studies were conducted for the feasibility and devolatilization efficiency of this method. A mathematical model was put forward to connect the following three parameters with one equation:Shear strength, particle size of CSM emulsion and the devolatilization efficiency. It proved theoretically that the water-jet method used for devolatilization has a good feasibility and excellent results. The proposed equations were verified by experiments. The study results showed that in a certain range, as the water flow rate and temperature increases, the final low volatile component content of CSM colloidal is decreased and good devolatilization achieved. This new method not only reduces the CCl4 content in CSM and improves the CSM product quality, but also recycles more CCl4 and decreases the production difficulties and costs. At the same time, it will reduce the CCl4 pollution in the atmosphere. The technology will have significant social and economic benefits. The main results were as follows:(1) The kinetic model of CSM latex demulsification and devolatilization was established, as shown below:The model shows that, under a certain condition, the devolatilization rate K is proportional to the shear strengthτ,τis mainly affected by the jet rate (water velocity), the higher the jet rate is, the bigger the shear strength is, then the smaller the average particle size d is, the higher the devolatilization efficiency can be obtained; It also proves that a positive relationship exists between devolatilization rate constant K and water temperature, the higher the temperature is, the greater the mass transfer coefficient k is, the smaller the surface tension coefficientτis, the higher the devolatilization efficiency can be obtained.(2) A new high-speed water jet method for devolatilization was proposed. With the high-speed shear flow, the CSM emulsion is quickly dispersed, broken, then became a large number of small uniform particles of CSM. It provides favorable conditions for the removal and discharge of CCl4. This method has been applied for national invention patent.(3) The Fluent software was used to simulate process and the electron microscopy and high-speed cameras was used to observe the experimental process and visualization; the other parameters which can affect the efficiency of devolatilization were also studied, such as incident angle a and the diffuser angleβ,and then an additional kinetic model was established.(4) The comparison of the experimental results and kinetic model showed that the theoretical model is basically consistent with the experimental results. That means the higher the jet rate and temperature is, the better the devolatilization efficiency can be obtained. In addition, the results showed the incident angle and diffuser angle will also affect the devolatilization efficiency. |
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