Dear Sir,
We have been experiencing a problem at feed filters of Diesel Hydrotreater due to which filters get chocked frequently. New filters are chocked after ~10 days whereas washed filters have a running life of 2-3 days. We have been cleaning the chocked filters by first soaking them in 20% caustic solution at 70 oC for 50min, hydrojetting with Demineralized water, dipping them again in 12% Nitric acid for 50 minutes and finally hydrojetting.
Filters are cartridge type with 25 micron sintered wire mesh. Feed is straight run gas oil from CDU column and light vacuum gas oil from VDU. In an analysis of the deposits, it was analyzed that majority of deposits consist of iron as Fe2O3 and nickel as NiO2 with little constituents of copper (CuO), Calcium (CaO), Mg (MgO), Chromium (Cr2O3), Zn (ZnO), Potassium (K2O), Sodium (Na2O), sand, silt and SiO2.
Despite the cleaning methodology being followed, service life of filters is very low. I want to know a better chemical recipe or a different cleaning method that will restore the service life of filters to its original condition.
If anyone knows how to troubleshoot this problem, please let me know. If any further information is needed, do let me know. Thanks.
Regards
Qasim
Edited by vectorangel, 16 January 2018 - 04:06 AM.