Remarks:
Vegetable and Animal Oils (Cleaning Procedure)
1. Butterworth the tank with seawater or freshwater with a temperature 20°C. above the melting point of the product to be cleaned. After sufficient pre-cleaning of at least 1.5 hours the temperature can be increased. Drying and Semi-drying ProductsThese are oxidising products and through reaction with oxygen they will dry and harden. Tank cleaning should be executed as soon as possible after discharge. High temperatures (e.g. cleaning or steaming) and heated cargoes in adjacent tanks should be avoided.
2. Butterworth the tank with cold to warm seawater or freshwater.If the product has a higher melting point Butterworth the tank with seawater or freshwater with a temperature maximum 10°C above the melting point of the product. After sufficient pre-cleaning of at least 1.5 - 2 hours the temperature can be increased. Fatty Acids or vegetable/animal oils with high free fatty acid contentsee the cleaning suggestion of Fatty Acids.
3. If seawater was used in step 1 it is of utmost importance to flush/rinse the tank with freshwater before cleaning as per step 3 is continued.
4. (Final cleaning)Prepare the following solution (A) in freshwater (see table):
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Solution A(emulsification) 0. 4 % RXSOL-20-2046-210 Butterworth the tank with the prepared solution for 1, 5-2, 0 hours by recirculation. The necessary temperature can be achieved / maintained by means of heating coils, cargo heat exchanger or Butterworth heater. Depending on the amount of product residues the solution can be used for 1 to 4 tanks.On some vegetable/animal oils it is recommended to saponify additionally the product residues (see
table): Therefore prepare one of the following solutions (B or C) in
freshwater (see table):
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Solution B 0.4 % RXSOL-20-2046-210 plus 2.5% Potassium Hydroxide (KOH) or Sodium Hydroxide (NaOH)
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Solution C 0.4 % RXSOL-20-2046-210 plus 2 - 5% RXSOL AL 2005
5. continued Butterworth the tank with the prepared solution for 1, 5-2, 0 hours by recirculation. The necessary temperature can be achieved /maintained by means of heating coil (service tank) cargo heat exchanger or Butterworth heater.If RXSOL-20-2046-210 is used the cleaning temperature should be 60-70°C If Sodium or Potassium Hydroxide is used the cleaning temperature should be 60.C.If RXSOL-20-2046-210 Marine is used the cleaning temperature can be 70-80°C. Depending on the amount of product residues the solution can be used for 1 to 3 tanks.
6. Butterworth the tank 1 hour with hot seawater
7. Rinse the tank with fresh water
8. Inspect the tank; if white residues or a white film is present (calcium/magnesium soaps or carbonate) Butterworth the tank with one the following solution: 3-5% phosphoric acid and 0.4% RXSOL-20-2046-210 (stainless steel only); or 3-5% nitric acid and 0.4% RXSOL-20-2046-210 (stainless steel only); or 5-10% citric acid and 0,4% RXSOL-20-2046-210 (also suitable for Epoxy Coatings) or 2% RXSOL-16-1011-025 Marine and 0,4% RXSOL-20-2046-210 (also suitable for Epoxy Coatings) The cleaning temperature should be moderate (50°C.) Use heating coils not the Butterworth heater.
9. Flush the tank with fresh water
10.Ventilate, mop and dry the cargo tank.
Note: for vegetable oils which can be cleaned only by the RXSOL-20-2046-210 (Solution A) the final cleaning can be carried out by recirculation or byinjection (see method 3).
