The Standard P&I Club focuses on the considerations for mariners when transporting biofuels as cargo. There are two distinct types of biofuel : ‘biodiesel’, which is derived from vegetable oils or animal fats (also known as FAME cargoes) and ‘bioethanol’, which is produced by the fermentation of various natural sugar and starch sources. Biofuel blends containing 75% or more of petroleum oil are to be subject to the requirements of MARPOL Annex I, while biofuels containing more than 1% but less than 75% of petroleum oil are subject to Annex II
The biggest issue for crews to consider when engaged in the carriage of FAME cargoes is that of water contamination. FAME cargoes are hygroscopic by nature and, as such, are extremely sensitive to contact with moisture either from physical contact or from the atmosphere.
Exposure to small amounts of moisture at any point in the supply chain may result in a FAME cargo exceeding the normal commercial sales limit for moisture content, which is normally fixed at 300mg per kg.
The need to avoid contact with water has a particular relevance to tank cleaning procedures. It is crucial post tank cleaning to ensure that the surfaces of the cargo tanks are thoroughly dried prior to loading any FAME cargo. Crews should also be aware of the propensity for FAME cargoes to cling to the surfaces of tanks only to re-emerge at a later date and cause contamination issues with subsequent cargoes.
Scrupulous attention to detail is therefore required to ensure that the tank cleaning routine meets the needs and characteristics of the cargoes before and after shipment of a FAME cargo.
FAME cargoes are, like many cargoes, susceptible to the effects of degradation when exposed to heat, certain atmospheric conditions and light. For instance, careful consideration should be given to the location of the tank that the FAME cargo is to be loaded into since the cargo may be affected by being adjacent to a heated tank.
Further details about the safe carriage of biofuels and FAME cargoes may be found by reading Standard’s P&I Club loss prevention bulletin on ‘Standard Safety Tankers’
Source: The Standard P&I Club
