Scaling up of the mixing step, from pilot plant to production line
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Hello everyone. I encountered a few issues during the actual process and would like to seek your advice. 1. Regarding the scaling-up of solid-liquid mixing and dissolution: During tests in the pilot plant, using a paddle mixer at 600 rpm, it took about 20 minutes to dissolve 10 kg of stabilizer in 150 kg of water at 50-60 degrees Celsius； When scaling up materials proportionally to the production workshop, the impeller blades are larger and require more power, but the mixing speed is slower. How can the dissolution time be determined and optimized? 2. Material circulation shear issue Background: A 3T small tank is connected to a 30T large tank and the materials can circulate between them. There is a high-speed shear pump at the outlet of the small tank; the materials pass through this pump before entering the large tank, which then pumps the materials back into the small tank. During production, after filling the large tank with 20–30 T of liquid, 1.5 T of liquid is pumped into the small tank, and circulation is initiated. During the cycling process, the powder is gradually added to the small container; it requires 3–4 shear actions to exert its stabilizing effect. But there is one problem: after the powder enters the large tank via the shear pump, it is very likely that it will not return to the small tank in a short time; rather, it takes a considerable amount of time. How can we ensure that all the powder returns to the small container through shearing? Is there any way to calculate or simulate this? If anything is not clear, please leave a message. Thank you all
Powder stabilizer shear – I don’t understand; what does shear mean?
There are two approaches to the first question: one is to use numerical simulation; if learning it on the spot is not possible, one can spend money to hire someone to carry out the simulation. Secondly, gain experience through experiments. Regarding the second issue, stir the large containers, draw conclusions from the experiments, and establish appropriate quality standards
First question: Dynamic cyclic mixing (similar to shear cyclic mixing) can be used in place of conventional stirring. Second question: It is best to use a continuous feeding method ；
They are raw materials for polymers; shear force is needed to break down their molecular structure so that they can function.
Are there any calculation methods, such as taking into account the size of the tank and the mixer, or is simulation the only option?
I don’t really understand what you mean. Actually, for both the first and second points, I want to know if there are any methods to calculate the required time based on the known conditions.