Which is the operative temperature of the liquid sent to the backwash filter unit which is showing fast plugging ? Generally the backwash filters are plugged not only from Iron-sulphide solid particles but even more often from aphaltenes like sub-products which are agglomerating at temperatures below 150C and are stopped on the filter surface creating a not permeable gel layer.
Increasing the temperature those sub-products are becoming less viscous and are passing through the filter slots. If the operative temperature cannot be increased then it is necessary to replace the actual filter elements with other more fit for the characteristic of the feed fluid and relative contaminantion.
Regards, Roberto of BEA TECHNOLOGIES.