The solution

At Howden, we not only solve our customers’ problems but we help them improve their day to day operations. For that reason, after undertaking an initial engineering study, we informed the client that by rerating the compressor not only they would solve their fouling problem but also reduce the compressor’s power consumption. After considering all available options, we finally offered the customer either a total rerate or a partial rerate with a 10% or 3% power reduction target respectively. Berre Petrochemical Cluster chose the latter, which involved the anti-fouling coating of newly designed diaphragms and existing rotors while the current impellers, labyrinths and casing grooves remained in place. The newly redefined diffusers and return channels were designed by Howden in such a way as to minimize losses and to maintain the required operating range.

We achieved this by comparing the performance of the existing stages with the newly designed stages by baseline comparison method. Then, through Computational Fluid Dynamics (CFD) we compared the existing design against the optimised one as designed by Howden. Basing our options on this method, we were able to guarantee a minimum power saving of 3% – or more if possible – by reducing the losses, thus increasing the pressure recovery and relative efficiency of the compressor.