RolleChim' Switch Condenser (SWC) technology for the recovery of Phthalic Anhydride (PA) from reaction gas has been developed in the last 40 years to reach the highest PA separation efficiency with the lowest energy consumption and the longest mechanical reliability for this kind of special equipment.
RolleChim SWC's are well known to be suitably designed to avoid quick saturation with PA of the upper bundle with collected PA, due to the possibility to manage oil flow rates inside the SWC giving also the flowing proven achievements:
higher PA recovery due to best suitable distribution of the product mostly in all finned tubes bundles;
valuable saving of thermal oil pumping energy;
no further devices/arrangement (i.e. flap valve at the outlet of gas side) are necessary.
One of the other main exclusive and valuable technical solutions in a RolleChim SWC is the advanced concept of tubes finning by means of automatic high frequency spiral finning welding system, which ensures a continuous and homogeneous presence of material between tube wall and fin root so allowing high overall thermal transfer coefficient across finned tube and higher corrosion resistance during the entire life-time of the SWC.
The pitch and diameter of the fins are properly calculated to have the highest fin efficiency and they are different in each tube bundle, so maximizing the PA recovery and the mechanical efficiency as well.
The upper hood of a RolleChim SWC is externally oil-traced to collect some PA during loading phase and to melt it down during the melting phase. The lower hood is externally traced with steam to avoid any possible ‘cold spot’ and subsequent possible solid deposit of Phthalic Acid.
RolleChim SWC's are designed to keep any of their components in the field of the elastic deformation during operation even under severe thermal stress conditions, so eliminating possibilities of plastic deformation of the material due to the continuous thermal switches.
Arrangements for installation of a rupture disk, for nitrogen blanketing as well as the possibility to hold a full batch of liquid product in the lower hood are the most important safety characteristics of RolleChim SWC's.