With the development of stearic acid as agents for food and chemical industry, more and more complicated process mixing machine is needed in order to meet customer’s product requirement. We would like to share the process of stearic acid mixing as following: after filling raw material into mixer, the vessel will be heated by heating jacket up to 110 degree temperature. Then, there will be reaction inside mixer body and pressure will be happen in it. The pressure inside body will be around 2-3 barg. Steam and other chemical reaction result this pressure and we need vacuum pump to extract steam out from mixer body through vacuum drum. After reaction, the product inside mixer need to be cooled by cooling jacket and then discharge final product through valve. So, which type mixer is suitable for above application? How to design the mixer to meet above process? Vortex has know-how to share our experience:
A. Which type mixer is suitable for above application?
According to our experience, ploughshare mixer is the best choice for stearic acid application because of following features:
- High speed mixing of reactants
- Prevention of overconcentration
- No temperature gradients in the reaction field
- Multiphase process (reaction, heating, drying, granulation, cooling)
It has a cylindrical shell with plough shovel welded or bolted on arms and the shaft runs at high speed to effect a fluidizing action. The plough shovel lifts the material upward, and the material settles in a pattern. Whirling, three-dimensional product movement makes output material with very high homogeneity within short mixing time.
B. How to design the mixer to meet above process?
1. Seal Part: Considering pressure inside mixer body, the seal part of main shaft and chopper is very important. As for chopper, double action mechanical seal is necessary to avoid leakage. As for main shaft seal, if pressure below 1 barg, packing seal can be used but if pressure is big, we must use double action mechanical seal.
2. Discharge: Due to the process material will become from liquid paste to powder, ordinary discharge valve is not good. So, we design segment ball valve for discharge in order to avoid liquid leakage and easy discharge.
3. Drive Power: According to process, it is low speed at first during reaction and fast speed at last when material becomes powder. So, the drive unit must be strong enough and safety factor should be beyond 1.3. Due to hydraulic motor is complicated, we think about to use another way to instead it. Firstly, we design fluid coupling between drive unit in order to keep stable torque when slow speed start. Furthermore, we use double speed motor to have strong power when slow start.
4. Plough Shovel: Considering full and complete reaction inside mixer and material feature, we design asymmetric plough shovel in order to make material easy flow.
Anyway, different application has different design feature. So, if you have any inquiry about this kind of mixer, please feel free to contact us.