Encrustation-free precipitation with mixing nozzle
Solids formation by precipitation crystallization is a common process. Especially in pharmaceuticals and food supplements, as pigmentation or as functional material, e.g. in catalyst production, solid particles are processed industrially. Requirements are defined particle size and size distribution, uniform crystal morphology and defined crystal structures. These characteristics ensure the desired bioavailability of pharmaceutical products, for example.
State of the art
In production, precipitation crystallization is usually realized in stirred tanks: The dissolved starting products are brought together and mixed in the tanks, react with each other and solid particles precipitate. Often particle agglomerates are formed, which then have to be comminuted by grinding. Mixing nozzles, on the contrary, offer the advantage that they produce very fine particles in the nano-/micrometer range under adjustable conditions. In continuous operation with highly reactive, highly concentrated materials, they have so far not been able to prevail, since encrustations of the mixing nozzle wall often occurred due to the necessary high supersaturation. These ultimately lead to clogging of the nozzle.
A new type of shielding flow mixing nozzle from the Institute of Thermal Process Engineering (TVT) prevents this undesirable encrustation by means of an shielding flow which is guided as a protective layer between the reaction solution and the mixing nozzle wall. The shielding stream, e.g. of water or glycerine, surrounds the reaction stream in which the precipitation takes place, thus preventing crust formation. The new mixing nozzle combines common Y- and cyclone mixers or confined impinging jet nozzles with an shielding flow fluid. Optimally, the fluid mixture can be further processed at the nozzle outlet so that the shielding flow fluid can be recycled and reused.
With the encrustation-free shielding flow mixing nozzle, the advantages of mixing nozzle technology can be used efficiently for material systems that tend to encrust: good reproducibility, rapid mixing and homogeneous particle formation. A long operating time is possible without clogging. If required, additional reagents can be added via the shielding flow.
Options for companies
A prototype of the shielding stream mixing nozzle was built at the institute and the encrustation-free precipitation of highly concentrated reaction fluids was proven. KIT is looking for partners for the industrial use of the mixing nozzle with the option of joint process integration for specific applications.
Your contact person for this offer
Dr. Aude Pélisson-Schecker,
Karlsruhe Institute of Technology (KIT)
Innovation Manager Energy, Innovation and Relations Management (IRM)
Phone: +49 721 608-25335