Sigma loading of organic coated tanks 2006

DOCUMENT NAME: Loading of organic coated tank Due to some incidents with organic coatings and contaminations from last cargo, we find it appropriate to raise a red flag All organic coatings will absorb some amount of product of low molecular structure The amount of absorption varies with the various producers Modified epoxies are the most exposed to this problem because of their abilities to carry low molecular structured products We normally check the coating resistance list to see If the coating is resistant to the cargo to be loaded ‘This is not sufficientTM Before you check for the cargo to be loaded, check under your previous cargo You might find that this cargo will have some restrictions on what you can load next As an example look up Methanol You will here find footnotes and (enclosure for Camcote MX) Under footnote 5, you will find restrictions on what you can load as next cargo Warm oil a.s.o ‘alternatively a non aggressive cargo (without notation).” One of the reasons for these limitations are damage that can be caused to the coating But another reason is the possibility for contamination to your next cargo Enclosed you will find a table showing how much Methanol can be entrenched in the coating after several hours of ventilation These figures are frightening A 1000 M3 tank can after 20 hours ventilation still contain 11,7 kilos Methanol When this is released into the next cargo, you can obviously end up with contamination PLEASE PAY ATTENTION TO THE FOLLOWING: Organic coated tanks Check resistance list for cargo to be loaded, and check under last cargo in tank Pay close attention to footnotes For cargoes requiring ventilation, allow sufficient time for absorbed product to be released from the coating Use steam on the coils to improve the release ability When tank is considered clean, dry and odor free, close all hatches and let stand for a few hours, with heating on the coils IF ODOR APPEARS AGAIN, THEN FURTHER VENTILATION IS NECESSARY Absorption and release profile of organic TIC systems Cargo : Methanol Amount of cargo in paint film g/m2 after ventilation period Time in hours Epoxy Phenolic 10 20 30 40 41 39 38 37 36 35 32 28 25 23.5 21.5 TO Maximum retention point (discharge of cargo) TI hour recovery/ventilation at 300C T2 hour recovery/ventilation at 300C T3 hour recovery/ventilation at 30C 50 Assuming a 1:1 Volume to Are ratio in a tank, and subsequent cargo s.g of 1.0 Then grams /m2 is equivalent to maximum potential in ppm of subsequent cargo, assuming full transmission of retained cargo into subsequent cargo Quotation from Cargo resistant list : SIGMA These water miscible cargoes should never be followed by ballast water, aqueous cargoes, water washing or steam cleaning, before cargo, which may have been adsorbed by the coating system, has been totally removed by ventilation of the tank It is essential that these cargoes are also loaded into completely dry tanks, and moister is excluded during carnage SIGMA PHENGUARD is resistant to methanol and ethanol at temperature up to 400C These cargoes must be free from contamination by other chemicals such as, but not limited to : formalin ; acetic acid; acetone and must contain less than 0,06% (600ppm) water The tanks must be completely dry before loading, and after discharge and ventilation THE FOLLOWING CARGO MUST BE A HOT CARGO OF LUBE / MINERAL / VEGETABLE OR ANIMAL OIL CARRIED FOR A MINIMUM PERIOD OF DAYS AT 500C OR DAYS AT 600C ALTERNATIVELY NON-AGGRESSIVE (WITHOUT NOTATION) NON AQUEOUS, +“ CARGOES MUST THEN BE CARRIED FOR AT LEAST 30 DAYS  ... of 1.0 Then grams /m2 is equivalent to maximum potential in ppm of subsequent cargo, assuming full transmission of retained cargo into subsequent cargo Quotation from Cargo resistant list : SIGMA. .. totally removed by ventilation of the tank It is essential that these cargoes are also loaded into completely dry tanks, and moister is excluded during carnage SIGMA PHENGUARD is resistant to... less than 0,06% (600ppm) water The tanks must be completely dry before loading, and after discharge and ventilation THE FOLLOWING CARGO MUST BE A HOT CARGO OF LUBE / MINERAL / VEGETABLE OR ANIMAL