Chemical process simulation using Excel or other software
What are the main considerations when we talk about scale-up in transfer processes?
1. When you’re in the lab, you have very small equipment, whereas in a production environment you go from tens of liters to hundreds or thousands of liters; hence, you’re increasing the dimensions. If you want to have the same performance or the same mixing pattern, then you need to coordinate between the mixing parameters that will generate in small equipment to big equipment. So, if you’re working in the lab with low velocity, high probability it will be a laminar regime, whereas if we go to the next step with normal velocity and obtain a high Reynolds number, then we will be in a turbulent regime. When we’re working on different regimes of mass transfer mechanisms, we are at a completely different mixing scenario, which will generate deviations in our research. So take care. Try to work in the same regime.
2. The second point is supercritical. You go to production and people tell you, “Okay, you know, this is the equipment we will involve in the production.” And they told you, “but we don’t have enough raw material. But we will use this equipment; it will be a very good approach to use the same equipment with low volume.” If you’re using the same equipment with a low volume and you’re using the same velocity in the low volume and big volume, then it is completely different mixing parameter. When you are using more volume, you need to allocate the RPM against the filling time and against the heat and mass transfer again because it will be different. If you go to a big volume, then a completely different distribution of energies occurs and maybe your universals will change. If you increase the volume, then you must adapt the mixing parameters to achieve good results.
3. Lab flow velocity versus impeller tip velocity: The flow is not only happening around impeller tip velocity. The tip velocity is maybe the maximum one you will achieve, but you have to distribute the flow. If the equipment is radial or axial, then the material will flow to the wall or to the top or bottom of the tank. The direction of the flow will change dramatically the diffusivity and the capability to progress; therefore, don’t try to generate the same in parallel time velocity as the universal parameter for scale up or technology transfer. Some of the unit operation will be controlled by impeller-type velocity. So, impeller tip velocity is a good candidate to be one of the parameters to keep fix for the scale up criteria, but not always is the unique one. I some cases, it is only the starting point for other mixing parameter considerations.
4. The right software will take into consideration many parameters that need to be evaluated at different points of your different levels. It will let you know which parameters are important and how to calculate them. But your interest is to generate an adequate mass exchange between materials in your process. Mixing parameters deviations may generate huge consequence in the quality of the end material, the operation in the facility and the yield of the process . One parameter will act one way and another in another way, and the RPM is only a tool to change the condition; however, what’s really controlling the process, in case of solid-liquid operation, is for instance, the accumulation of solids in the bottom, the dissolution rate or their combination. Every mixing parameter should be different at different parts of the vessel. This complex situation is our main challenge.
Read more here – https://visimix.com/chemical-process-simulation/
The Influence of Mixing in the Process
New methodology using VisiMix software for the purpose of checking the influence of mixing in the processes.
VisiMix Demo Operation
Learning how to input data into the VisiMix software and get results the will help us understand the influence of mixing in our processes.
Learning how to set up the relevant experiments at the lab scale, to develop the processes from an engineering point of view.