Optimal dosage strategies for filter aid filtration processes with compressible cakes

We establish optimal time-dependent dosage strategies for compressible filter aid materials, focusing on dead-end filter aid filtration processes operated in constant flow mode. To this end, we apply a direct optimal control approach by repeatedly evaluating a mathematical filtration model with filter aid con-centration as the unknown time-dependent control function. Our algorithm iteratively constructs the sought-for trajectory to minimize a cost functional representing previously defined performance goals. We evaluate our optimal control approach for two different model formulations. In the first one, all impu-rity particles are separated by pure surface filtration on top of the existing filter cake, whereas in the sec-ond one, the model is extended toward depth filtration in the filter cake. Particularly for the latter, optimally controlled dosage strategies yield a significant performance improvement of up to 30% reduced filter aid consumption compared with the already optimized but constant filter aid dosage.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

This study establishes optimal time-dependent dosage strategies for compressible filter aid materials used in dead-end filtration processes. A direct optimal control approach is employed to minimize a cost functional representing performance goals. The results show significant performance improvement in filter aid consumption when using optimally controlled dosage strategies, particularly in depth filtration processes.