A novel in-situ combustion concept for hazardous waste clean up

In this study, a new in-situ combustion concept capable of enhancing the burning of oil soaked sand without requiring atomizing nozzles, moving parts and compressed air for operation is presented. The working principle is based on the use of immersed noncombustible and thermally conductive objects to effectively transfer the heat from the flame back to the fuel bed (contaminated sand) such as to create a feedback loop, which sustains a significantly increased burning rate. The concept named Flame Refluxer^TM was developed as a Bureau of Safety and Environmental Enforcement (BSEE) study (Contract Number E14PC00043) in 2014 and was successfully shown to work in burning oil-water emulsions up to 60% water content. The current work applies this concept to oil contaminated sand. A series of tests have been performed with mimicked scenarios to show the viability of the design concept. Apart from increased burning efficiency, reduction of CO and smoke is also apparent. The experimental results are used to validate a computational model, which can be then used to further explore the controlling parameters such as sand porosity, concentration of oil in sand, scale, and object geometry.