Despite a number of theories, equations and other academic research in the public domain, a common issue amongst manufacturers across the process industries is successfully scaling up products formulated in the lab
As agitators are generally carrying out relatively simple tasks, it is possible to forecast their performance at a larger scale with a high degree of certainty. High Shear mixers such as rotor/stator devices are much tricker to forecast. The versatility of these mixers means that more complex factors are involved, with many mixing operations such as homogenising, particle size reduction, emulsification, etc. occurring at the same time.
One of Silverson Machines’ unique selling points is the ability to scale up our mixing equipment from the laboratory to full scale production models. With over 75 years’ practical experience in scaling up, we offer unrivalled know-how and expertise, and time and again, we have found scalability is a deciding factor when customers are looking to purchase a mixer.
Many mixer manufacturers offer high speed laboratory mixers that have no production equivalent. Silverson, on the other hand, offers the largest range of capacities from a single manufacturer – from 1 ml laboratory units up to some of the largest disintegrator systems on the market – with all Silverson mixers manufactured to the same precision engineered tolerances. As a result, we can offer scalable results across our entire product range.
In this article we discuss how Silverson have helped one of our customers take their application from the laboratory, all the way to full-scale production.
Company continually scales up mixers for industrial wastes application
Silverson received an enquiry from a chemical company looking to reduce the size of industrial waste pieces (similar in appearance to rubber) in water to produce a fuelling substance.
At first, the application was tested on a small scale; as the end product could be volatile it was important to the company to make sure the process was safe before testing larger batches.
An L5M-A Laboratory mixer fitted with a Duplex assembly – a configuration specifically designed for disintegration and dissolving of solids – was the initial mixer that the application was tested on and it produced good results. As a result of the trial the company purchased the mixer to continue testing and analysing the results. The company was encouraged by the results of this testing and they returned to Silverson to discuss scaling up their laboratory mixer.
To scale up they purchased two in-tank High Shear Batch mixers fitted with Slotted Disintegrating and Square Hole Disintegrating workheads. These mixers were installed in their own pilot plant which was processing around 200 litres in volume.
Prior to disintegrating the waste with the in-tank Batch mixers, the company was pre-grinding it to reduce the size. They carried out more trials to try and eliminate this step from the process.
The application was tested on a 250 litre Silverson Bottom Entry Pilot plant to see what the results would be on an even larger scale. They’d been pre-grinding the pieces into water, as the waste could be as large as 10cm2. During the trial different sizes of these pieces were tested to try to reduce the size as much as possible before the product went through an In-Line mixer as a refining second stage. The results obtained from this trial were better than all the tests they had previously run, and the Silverson mixer was able to reduce the pieces down to <100µ, well below their objective of <200µ. It also meant they were able to eliminate the pre-grinding stage.
The company are now planning to test an even larger Bottom Entry unit before purchasing a Silverson D2500 Disintegrator/Dissolver, the largest model in Silverson’s product range. The D2500 is capable of processing batches of 30,000 litres, which would mean that Silverson has successfully scaled up their application all the way from the laboratory to production on a massive scale.
Part of the key to Silversons’ success – and that of our clients – is the accuracy with which we can predict the performance of our production scale mixers based on laboratory trials. We see no point using a laboratory mixer capable of speeds of 25,000 rpm or more if the results cannot be replicated in production. That’s why our laboratory mixers are designed and built to the same tolerances as our production units; comparable rotor tip speed and shear rates across our entire product line means scalable results, every time.
You can learn more about RPM vs. Peripheral Tip Speed in one of the Silverson Science animations, available to view on the Silverson website.
If you want to know more about scale-up or wish to arrange a trial, contact Silverson today.
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