RIASSUNTO
W.A. Dahl, R.R. Lessard, E.A. Cardello, Exxon Research & Engineering Co., D.E. Fritz, Amoco Corp., F.S. Norman, Aramco Services Co., J.D. Twyman, Arco Exploration & Production Technology, E.W. Clayton, Chevron Corp., B.L. Knight, Marathon Oil Co., R.D. Crane, Mobil Oil Corp., S.J. Johnson, Phillips Petroleum Co., B.R. Martin, Texaco Inc.
Abstract
Solidifiers are an existing technology that have the potential to be applied to marine spills especially for protecting shorelines. This paper summarizes the results of a research program conducted by Exxon under the auspices of the Petroleum Environmental Research Forum (PERF) to determine the applicability of the use of solidifiers for responding to oil spills. The program included laboratory evaluation of commercially available solidifiers, field evaluation to extend existing application techniques to solidifiers and identification of recovery, removal and disposal options.
Background
Since 1968 Exxon has invested heavily in developing new technologies for responding to oil spills. In the early 1970s, the U.S. EPA and Exxon conducted research on the potential use of solidifiers in a scenario in which a vessel loaded to capacity was in imminent danger of sinking or breaking up1. The strategy was to solidify the oil in the vessel hold to prevent its release to the water. Limitations identified in this use of solidifiers included: the product had to be uniformly mixed with the oil which could be difficult for vessels with large tanks, the tanks would have to be accessible, the pumps and equipment for injecting and mixing the components would have to be readily available and the amount of product required to solidify the entire cargo could be very large. Nevertheless, this use of solidifiers was judged to have some application under very special circumstances.
Today, Exxon continues its strong commitment to the development of new oil spill response technologies. During the Valdez clean up, a system was created for tracking and evaluating new technology proposals from inventors and vendors. Solidifiers were among the many oil spill response proposals submitted to Exxon by third parties. The solidifier proposals were evaluated and found to have potential future application for oil spill response. As a result, in early 1992 Exxon initiated a program to identify solidifiers that potentially could be used to protect shorelines from oil spills.
Past evaluations of solidifiers concluded that the cost of their application to large spills would be prohibitive due to the large amount of material required to solidify the entire spill. Environment Canada has commented that the use of solidifiers in open water is questionable due to the large amount of solidifier required. However, the amount of solidifier can be significantly reduced if only the leading edge of a spill in calm water such as a harbor or lake is solidified to help prevent the spilled oil from reaching the shoreline. Due to the significant incentive, both environmentally and financially, of preventing spilled oil from reaching shorelines, it was felt that detailed testing of solidifier materials for application to spills in calm water was warranted.
Solidifiers have been available for over 20 years; however, their applications have been primarily for handling small laboratory spills. There has been little documented use of solidifiers on field spills. Also there have been no coordinated studies comparing the various solidifiers, their effectiveness to solidify various petroleum oils and their application for large land or water-based spills. The possibility of reducing the spread of waterborne oil by solidifying it, together with increasing recovery and removal rates, is a concept with significant potential benefit.
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