Seed Waste

Infobox on Seed Waste
Example of Seed Waste
Facts
Origin	Chiefly South America, Asia
Stowage factor (in m3/t)	1,39 to 2,09 (m3/t)
Angle of repose	Not applicable
Humidity / moisture	See text
Oil content	See text
Ventilation	-
Risk factors	-

Seed Waste

Description

Seed Waste (further referred to as Seedcake) is the residue remaining after the removal of oil from any oil-bearing seeds, cereals and cereal products, and any other commodities with similar properties. This is achieved by mechanical crushing or by a process known as solvent extraction. Seedcake is a by-product of the production of vegetable oils from the oil-bearing seeds or grains, and is principally used as an animal feed or fertiliser.

With some exceptions (for example, solvent-extracted seedcake with low-residual oil and moisture, which is not regarded as hazardous), seedcake is a hazardous cargo that can self-heat owing to the presence of moisture, residual oil or both. Although the self-heating process is slow, it can cause the bulk temperature of the cargo to rise to the point at which it ignites spontaneously. The shipper is required, according to the provisions of the IMSBC Code, to provide a certificate from a person recognised by the competent authority of the country of shipment confirming the oil and moisture content of the shipment, on the basis of which the UN number of the cargo is determined.

The moisture content of a seedcake cargo is relevant since high moisture content promotes microbiological activity, which may be responsible for the initial rise in temperature up to about 70ºC and deterioration in the quality of the seedcake. This activity alone will not cause the seedcake to ignite, but it will accelerate oxidation of the residual oil, which in turn can cause the temperature to rise sufficiently to the point at which the seedcake will spontaneously ignite.

According to the IMSBC Code, seedcake derived from solvent extraction has an additional hazard arising from residual flammable solvent mixed in the cargo. Seedcake determined to be non-hazardous, and certified as such, is non-combustible and has a low fire risk.

It is important to measure the cargo temperature before and after loading, and during carriage to ensure that incipient signs of self-heating are detected and appropriate action can be taken. Digital thermometers of the type shown below are employed for this purpose.

There are four types of seedcake listed in the IMSBC Code defined by the oil and moisture content and the method of production. These are summarised below :

• Mechanically expelled seeds, containing more than 10% of oil or more than 20% of oil and moisture combined.
  
• Solvent extractions and expelled seeds, containing not more than 10% of oil and when the amount of moisture is higher than 10%, not more than 20% of oil and moisture combined.
  
• With not more than 1.5% oil and not more than 11% moisture.
  
• NON-HAZARDOUS
  

Solvent-extracted rape seed meal, pellets, soya bean meal, cotton seed meal and sunflower seed meal, containing not more than 4% oil and 15% oil and moisture combined and being substantially free from flammable solvents.

Seedcake is usually transported as a dry bulk cargo, in the form of pulp, meal, cake, pellets and expellers.

Self-heating and spontaneous combustion
The main hazard of seedcake cargo is the risk of self-heating and spontaneous combustion. Ships carrying hazardous cargo are required to have on board a valid document of compliance confirming the ship’s suitability for carrying dangerous goods. Self-heating leading to spontaneous combustion in a cargo of seedcake can be triggered by microbiological activity or exposure to a source of elevated temperature in the hold or both.

As with other dangerous goods, the IMSBC Code requires hazardous seedcakes to be kept as cool and dry as reasonably practicable, and stowed away from all sources of heat or ignition.

Sources of heat and ignition include:
• hot fuel oil tanks • hot fuel oil lines • hold lights left on • poor electrical wiring • carelessly discarded smokers’ materials In respect of smokers’ materials, it is important to emphasise that live cigarette ends can be transferred from the shore side and buried in the cargo during loading operations. This is particularly hazardous if it comes into contact with extraneous combustible material in the cargo. The IMSBC Code is quite particular about UN 1386 (b) and UN 2217 cargo, stating that if the bulkhead between the cargo space and the engine room is not insulated to class A-60 standard, solvent extraction seed shall be stowed ‘away from’ the bulkhead. This means that a ‘false bulkhead’ may have to be constructed if applicable. However, it is not just hazardous cargo that requires such protection. The heating of fuel oil tanks and the warm machinery spaces adjacent to cargo holds are frequent causes of heat damage to solid bulk cargo, particularly grain cargo.

Due to their oil and moisture content, this cargo can present a significant fire risk due to self-heating and spontaneous combustion.

Reference is made to the relevant IMO publications of hazardous cargo.

Full information on this product is in the process of completion.