How to translate your process into mixing tasks
When optimizing or developing a new process, in which agitation technology often plays a significant role – it is very important to understand the target precisely in order to do the design.
Main targets for the industrial process are mostly connected to properties like
The order of importance depends very much on the process itself.
For an agitated process, there are several mixing tasks, as can be seen in Fig.1
Besides the main mixing tasks, which are:
There are a number of “side tasks” which, depending on the corresponding agitated process, can be just as important as the mixing tasks already mentioned or even more important. These are mixing tasks like surface entrainment, feed point selection, management of different rheology,… just to mention a few.
Only a very good analysis of the process will help. The target is to find out which are the significant parameters – now from the viewpoint of the mixing tasks - that contribute to the desired quality and capacity of the process.
It usually starts with a process analysis:
First, the specific process is analyzed and discussed with the customer. This includes examining basic process characteristics such as
The aim always is to adapt the stirring technology, in most cases together with the vessel and internals, to the customer's process (see Fig. 2).
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Agitator selection and scaling to industrial scale
The team in the technology center selects the appropriate agitator that meets the specific requirements of the process. Agitator design at EKATO is performed based on more than 90 years of experience in most different agitated processes, so a lot can already be solved on the basis of experience.
Experimental studies
In more difficult cases, there is the option to investigate the influence of the mixing strategy on the process by testing in a laboratory or in a pilot plant. To do this, we carry out series of tests in order to optimize the performance of the agitator and the reaction conditions. Very different stirring parameters are tested. Based on the process parameters, a decision is made on the scale on which these tests should be carried out. The data collected from the tests is analyzed to evaluate the efficiency, product quality and safety of the process. As an example, the surface entrainment of “fly ash” had to be investigated with experiments, delivering an efficient, reliable and scalable solution (Fig. 3).
Flow Modeling – CFD Studies
For a lot of processes it is necessary to visualize the resulting flow inside the agitated vessel – for these cases a team of experienced CFD (computational fluid dynamics) engineers uses sophisticated tools in order to control the flow properties, especially if there are certain vessel internals or quite complicated flow combinations / different rheology to take into account. It is very important to have a sound data base for these simulations. In most cases they are verified by piloting or evaluation of existing process data. More simple studies are already valuable to estimate if flow properties and power input generated by a mixing system are suitable to run the process in a reliable / efficient way (Fig. 4)
Scale-up to commercial
In an optimum case, the scale-up can be done on the basis of already existing process experience. What sometimes makes it quite different is, that for more or less every mixing task there is a different “scale-up rule”. Nevertheless, for a well-understood process the scale-up rules for the significant mixing tasks are well known at EKATO - and these rules are the basis for selecting the right equipment. In addition to this, CFD simulations are also a quite valuable tool for scale-up.
In more difficult cases, especially regarding new or very demanding processes, simulation or testing are necessary. After successful simulation and/or testing, the stirring technology and process are scaled up to industrial scale.
Our experts work closely with customers at every step to develop tailor-made solutions that meet the specific requirements of each chemical recycling process. Our knowledge and experience in stirring and mixing technology is used to create innovative solutions.
If you are interested in more details, register for our free "How to translate your process into mixing tasks" webinar on August 15: