| As an important chemical intermediates, the manganese sulfate has been playingan important role in chemical production. In this paper the basic overview of manganesesulfate and manganese sulfate crystallization technology is discussed, then anenergy-saving manganese sulfate continuous heating up and crystallization technologyis put forward through the field investigation in the factory aiming at solving theproblem of serious fouling and energy consumption etc. in the traditional manganesesulfate high temperature evaporation and concentration technology. In this papertheoretical analysis, numerical simulation, and experimental research etc. are use toresearch and analyze the energy-saving manganese sulfate heating up and crystallizationtechnology.Firstly simplify the model studied appropriately, and then the numerical simulation ofthe flow field and the temperature field in the tube that inserted the vibratoryspiral-insert is carried out. The result shows that: Applied the vibrating spiral-insert andthe fluidized particles, the velocity in the main area of the tube center and the boundarylayer region are obvious larger than that in the empty tube. It can be seen from themagnitude of the flow velocity that the maximum velocity is1.33m/s which is66.25%higher than the inlet velocity of0.8m/s. This shows that the application of the vibratoryspiral-insert and the particle enhances the disturbance to the fluid, thins the thickness ofthe boundary layer. In the position of the same cross-section, the temperature in thecenter of the tube with the spiral-insert is0.12℃higher than that in the empty tube; Inthe position X=16.6mm of the boundary layer near the wall, the temperature in thetube with the spiral-insert is3.5℃higher than that in the empty tube. Therefore theapplication of the vibratory spiral-insert and the particle strengthens the heat transfergreatly.Secondly based on the numerical simulation, the cold model experiment is carriedout. By observing the movement characteristics of the vibratory spiral-insert while thefluid flow through, the outer diameter, screw pitch, wire diameter, length and otherparameters of the spiral-insert are optimized from the view of the best fouling removeand prevention: Using the spiral-insert with the outer diameter and the tube diameterratio of0.7and the screw pitch and the tube diameter ratio of0.75, the best foulingremove and prevention effect appears while the velocity range from0.6m s1to 1.0m s1. When take the outer diameter of the built-in vibratory spiral-insert of24mm,the screw pitch of22mm, the wire diameter of1.5mm, it is most suitable for industrialproduction.Finally in order to checking and confirming the cleaning ability of theenergy-saving manganese sulfate heating up and crystallization technology, the thermalmodel test using the vibrating spiral-insert and the fluidized particles with the optimizedvibratory spiral-insert is carried out. The result shows that when the mean velocity inthe tube is0.8m s1, as the absolute supersaturation csurnear the tube surface is less than3.09%, the heat transfer coefficient is not reduced under the condition of tubes withoscillatory spiral-insert after continuous operation of60minutes while it decreases by65%under the condition of hollow tubes. When c suris more than3.09%, the volumefraction of the solid-particles have a significant effect on the heat transfer and foulingprevention performance: compared with the condition of tubes only with oscillatoryspiral-insert, the heat transfer coefficient does increases by15%under the condition oftubes with spiral-insert and1%volume fraction of particles. The energy consumptioncomparison analysis is carried out between the new manganese sulfate continuousheating up and crystallization technology and the traditional high temperatureevaporation and concentration technology from the perspective of feasible absolutesupersaturation. It is found that the former one has the obvious advantage of energysaving about53%. |
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