CONTINGENCY PLANNING FOR EMULSIFIED FUELS¹

A considerable amount of research has been undertaken over the past 15 years into the fate / behaviour, potential impacts and response options for ORIMULSION®, a specific trademarked emulsified fuel. Although it is the only commercially available product of this kind at present, the same technology can also be applied to other heavy feedstocks to facilitate their handling and transportation. In the early 1990s a number of emulsions of refinery residues were trialed, and since then several other emulsified fuels have been developed, albeit so far with limited application or commercial success. However, as technology and economics change it is likely that other emulsified fuels will be developed.

The characteristics of any emulsified fuel and its formulation are developed to meet a number of criteria that take into account ease of production, handle ability, stability, economics and end-use together with environmental impact and spill behaviour. Consequently not all emulsified fuels will necessarily have the same characteristics or behave in the same way.

A key consideration is the surfactant package used to stabilise the emulsion. This will play a key role in determining the overall ecotoxicological impacts of the fuel and in dictating the dispersion / coalescence equilibrium for an emulsified fuel following a spill incident.

In extreme cases, differences in the surfactant package could make the difference between an emulsified fuel dispersing virtually entirely versus almost instantaneously coalescing. Given the extreme viscosity of the re-surfaced bitumen, this potential difference in fate and behaviour would have a considerable influence on potential impacts and, consequently, on the choice of appropriate spill response strategies.

This paper explains how the surfactant package in an emulsified fuel should be fully considered, and its potential influence on response options taken into account, in the Contingency Planning process.