Application of Flame RefluxerTM Concept to ISB – Experimental Results of 5 Field Trials in Mobile, Alabama

A new in situ burning (ISB) method, capable of enhanced combustion of oil slicks in containment booms, is analyzed. The concept named Flame RefluxerTM is based on the use of immersed thermally conductive objects to transfer heat generated by the combustion back to the fuel to create a feedback loop. The resulting enhanced heat transfer from flame back to the fuel helps to sustain a significantly increased burning rate. The project spanned a period of two years ranging from bench scale to large-scale experiments in the laboratory and culminating in outdoor field experiments. Five large-scale field experiments were performed at the United States Coast Guard (USCG) test facility at Little Sand Island in Mobile Bay, Alabama. A confined liquid pool (1.4 m diameter) was continuously fed to maintain a constant oil layer thickness of 1 cm floating over water. A 0.5 cm thick copper blanket, 94% porous, was immersed in the oil and served as a heater for the oil slick. Conical shaped copper coils extending out into the fire were attached to the blanket and were used to collect the heat from the flame. Experiments resulted in three major outcomes: i) Additional heat transfer to the fuel lateral dissipation through the copper blanket increased mass loss rate by 6 times ii) Heat stored in the blanket facilitated burning of the heavier components of crude oil such as tar, resulting in negligible residue (15 times less than baseline). iii) Black smoke was reduced by 50%. The Flame RefluxerTM is robust, easy and cheap to construct and has no moving parts. The field experiments demonstrated the feasibility of the technology to be used in efficient clean up of oil spills using ISB