Development of the “Next Generation” Chemical Dispersants

ABSTRACT In order to fully appreciate the development trend for the “next generation” chemical dispersants for oil spills, the current status of this field is briefly reviewed. Recent applications illustrate the specific beneficial potential role of chemical dispersants in the oil spill control, as well as their limitation. The present mechanism of dispersing oil spills by the application of chemical dispersants is well understood and is the subject of many technical papers. While there is some variation in the relative performance and toxicity of the many commercially available products, they all require mixing after application. In instances wherein the dispersant has been marginally effective, inadequate mixing was usually the reason. Thus, mixing is the limiting step rather than application. The mixing of an oil spill by boat propellers, fire hoses, etc., is laborious and time consuming. However, dispersant may be readily applied to large areas by aerial application similar to “crop dusting.” In some instances, the oil spill may even become inaccessible for convenient mixing (e.g., under piers, shallow water). Hence, the elimination (or minimizing) of the mixing step would be a major improvement in the dispersion process. The “next generation” oil spill dispersants will require little or no mixing energy and will approach spontaneous emulsification. The mechanism of “self-mixing” will be outlined in this presentation. Performance data comparing this generic type of chemical dispersant with the more conventional systems commonly used will illustrate the major differences. Another important aspect of this system is the resultant dispersed oil droplet size. The remaining concerns and other considerations requiring further study will be discussed.