Gassed stirred tank reactors have an important key function in many industrial processes. Besides the ‘economies of scale’ and advances in process result, cost optimization of such systems is fundamental. Ekato has developed the ’+’ technology which can be integrated into different impeller types to improve the overall performance of gassed applications. A typical application is the biological leaching of metals: large tanks with heavy ore suspensions and large oxygen demand to supply the micro organisms that control the leaching process.
The main feature of this technology is the considerably simplified method to disperse and dissolve a gas into a process fluid. Typically reactors are equipped with ring spargers with multiple small holes or gassing nozzles which are very susceptible to blockages, e.g. in case of a power outage. Product or slurry enters the ring and blocks the nozzles, and frequently wear occurs at the nozzle outlet. To overcome these and other disadvantages the company developed and patented the new gassing ‘+’ technology. The gas is directly fed through one central feed pipe coming from the vessel bottom into a rotating gas distributor which is integrated into the impeller. The non-contacting and therefore maintenance free gap between the feed pipe and the rotating gas distributer has the function of a ‘hydraulic seal’. The gas flows via the hollow spars directly to the outer areas of the impeller blades where it is dispersed into zones of highest shear. Therefore the impellers equipped with the ‘+’ technology show an increased performance of up to 20 % more gas-liquid mass transfer performance compared to conventional gassing systems.
