Prior loading of any Veg Oil cargoes, it should be noted that the last three cargoes must be lead-free.
Also, ensure all Cargo Tanks, pipelines and pumps must be well drained and dried.
The Veg Oils are very susceptible to Salt Water. Any contact with Sea water will result in rotting /damage of cargo.
It should be ensured that after loading is completed; all cargo tanks are checked by Ship’s Officer along with attending surveyor, with a bottom sampler to ensure no water is trapped/loaded at Load Port.
All Butterworth openings should have Oil resistant packing’s. Same to be hammer tight. The Tank dome and Ullage port packing’s should be checked for tightness.
All precautions to be taken to prevent any possibility of ingress of water.
Also, on weekly basis at sea, the cargo tanks should be checked with a bottom sampler for any existence of water.
MANUAL SQEEZING IS REQUIRED FOR ALL VEGETABLE OIL CARGOES, AFTER BULK DISCHARGE.
Several Grades of Palm Oils are loaded on board ships as can be seen in the table mentioned below. Sometimes a blend of these products are also loaded or blended on board.
A Stowage Plan is to be properly prepared catering to the requirement of various Grades and several parcels (as much as 10 to 12) generally loaded on board ships. The Load port and Discharge port rotations will have to be accounted for, which is normal with any grade of oil.
It is generally seen that Loading is overall (through Tank Openings on the weather deck, via Tank domes / Butterworth pockets). However, cargos in larger quantities are loaded through vessel’s manifolds.
Utmost care should be exercised in blowing with the air of all ship’s lines used in the loading of any grade of cargo (soon after loading each parcel) to clear out remains or else may be solidified.
Proper segregation between grades to be maintained as per Charter Party requirements.
The calculations are based on Ullage measurements from Gauging Points of tanks and obtaining the volume loaded in each tank. Same multiplied by the density of cargo for that temperature. At this stage suggest taking an average temperature of cargo (top / middle / bottom). The density table is enclosed herewith for reference.
Knowledge of Cargo Characteristics and Heating requirements are of prime concern.
|MIN oC||MAX oC||MIN oC||MAX oC|
|– Crude Palm Oil (CPO)|
– Neutralized Palm Oil
– RBD Palm Oil
|– Crude Palm Olein|
– Neutralized Palm Olein
– RBD Palm Olein
|– Crude Palm Stearin (CPS)|
– Neutralized Palm Stearin
– RBD Palm Stearin
|– Palm Acid Oil|
– Palm Fatty Acid Distillate (PFAD)
|– Palm Kernel Oil||27||32||40||45|
|– Palm Kernel Olein||25||30||30||35|
|– Palm Kernel Stearin||32||38||40||45|
The table is to be used as a guideline only. Any temperature requirements from the surveyors at Load Port to be forwarded to the Owners for verification and confirmation.
For Planning Stowage, following criteria should be considered:
- Palm Fatty Acid Distillate (PFAD) and Palm Acid Oil: ruins the coatings of Cargo Tanks, due to its acidic characteristic. Same should never be loaded in coated or partially coated tank. Also, suggest loading in tanks closest to pumproom, as possible to cater to its high heat requirements and enable easier discharging. Attempts should be made to discharge this cargo first so that the pipelines , and cargo pumps can be automatically cleaned of residues with lighter grade cargoes. Where center tanks are not coated, such high heat cargoes should be loaded in them to get an insulation effect from wing tanks (and double bottom tanks where exist).
- Palm Stearin: is another high heat cargo and should be stowed in tanks as close as possible to Pumproom and preferably in center tanks. Stearin products do not damage the coatings but tend to leave heavy sediments in tanks after discharge. All cargo pumps and pipelines used for discharge should be thoroughly blown through to ensure nil deposits.
- Palm Olein: is the simplest of grade. Same suggested to load in forward tanks, especially wing tanks, as does not require much heating. Also, this product does not pose any difficulty in discharging. However, blowing of cargo lines with air is a standard procedure after discharge.
- Crude Palm Oil: is an average heated cargo. Same does not pose difficulty in discharging. However, manual squeezing of all tanks would be required when tanks are being stripped. This product can be loaded in wings or center tanks, including coated tanks.
All heating coils should be pressure tested to minimum 8 bars and for a period of approx 30 mins. The Master/ Chief Officer should be satisfied with the condition of coils prior loading such oils.
It should be ensured that the heating coils are free from Copper Content or else same would lead to cargo damage. Heating coils via Yorcalbro (Aluminum + Brass alloy) are not suitable for Palm Oils.
- Heating shall be effected by Hot water or if this is impracticable, by low pressure saturated steam. Pressures shall not exceed 1.5 bars gauge.
- Carriage temperatures should be strictly adhered to during voyage, as per table.
- In sufficient time, prior to arrival at Discharge Port, heat should be applied gradually to ensure that the cargo is within the prescribed range of temperatures, for discharge.
- The increase in temperature of the oil during a period of 24 hours MUST NEVER EXCEED 5O Sudden rise in Cargo temperature can lead to damage to quality of cargo.
- The Top and Bottom temperatures should be maintained as nearly equal as possible. Difference exceeding 5OC in the temperature of the oil in different parts of the tank SHOULD NOT BE PERMITTED.
- A record of Daily temperatures during voyage should be maintained, preferably with bottom and top readings. Same may be requested at Discharge port or by charterers.
Generally a discharge plan is agreed between the ship’s Chief Officer and receivers. All considerations should be made prior agreeing to a plan including vessel’s list/trim and stresses.
Also, high heat cargoes should be discharged first, preferably.
Temperature measurements to be made even while discharging is in progress. Heating coils to remain crack open where cargo temperatures are to be maintained.
All pipelines/pumps to be blown through fully as each grade of oil is discharged.
Generally shore squeezing gangs are employed. Care should be taken to get maximum cargo squeezed and discharged, or else same may pose problems during tank cleaning.
Hot sea water above 80OC will be required under a pressure of 8 Bars to achieve satisfactory results, particularly with CPO, CPS and PFAD cargoes.
Above parameters are the average requirements.
It is suggested that cargo tanks may be filled up with a foot of sea water and heated up using heating coils. The hot water thus, does not allow the sediments to harden and same washed away easily when tanks are Butterworth.
Duration of Cleaning will depend on the grade involved. However, 3 Hours of washing each tank is re-commended.
Thereafter, local cleaning, de-mucking and hosing down of bottom are generally carried out.
Lastly rinsing tanks / pipelines with fresh water for about 1 hour.
Thereafter, draining, mopping up and drying of all tanks and pipelines.
SOYBEAN OIL / SUNFLOWER OIL
Like Palm Oils the density of these oils is around 0.9
Both cargoes are non heated types as long as vessel is not operating in zones, where cargo temperature falls below 10C. General precautions as in case of all Veg Oils are to be carried out.
Density Tables are hereby enclosed for reference. Squeezing at Discharge Ports will be carried out. As it is not a heated cargo, this is carried out by ship’s crew, generally.
Loading and discharging of these cargoes is very simple as it’s a light product.
ONLY COLD SEA WATER SHOULD BE USED for 1st washing. Recommend for a period of 3 hours at 8 bar pressure.
Thence, Hot Butterworthing at 80OC may be given. This is generally not required if level of cleaning is achieved by 1st washing only.
Butterworthing with Hot fresh water for ½ Hour followed by draining and drying up of tanks, pipelines and pumps.