THE USE OF ADVANCED ACOUSTIC CAVITATION FOR APPLICATIONS IN THE OIL AND NATURAL GAS INDUSTRY

Argonne National Laboratory (ANL) has conducted research involving acoustic cavitation (sonication) combined with advanced oxidation techniques for several applications for the oil and natural gas industry. Acoustic cavitation involves the application of high intensity sound waves (having strong oxidation potential) to a liquid phase. Microbubbles form which grow to a critical size (on the order of a few angstroms) which then implode. At the collapsing bubble interface, temperatures in the order of ~5,000o K and pressures on the order of 500 to 1,000 atmospheres have been estimated, while the bulk solution stays near ambient. This creates conditions that are very effective for cleaning industrial equipment. This process can be enhanced by the combination with other advanced oxidation techniques such as ozone injection, vapor stripping, and/or the addition of hydrogen peroxide. ANL has conducted research into mineral scale removal using this advanced acoustic cavitation technique. Barium sulfate (BaSO4) scale was used as the surrogate scale. During these tests, ANL was able to break up scale with as large as 5/8-in thickness. Preliminary results to date indicate that better than 90% of surrogate scale was removed, after a 15-min application of sonication (20 kHz) at 20 W/cm2. Additional research (for the textile and forest products industries) conducted at ANL included the removal of solidified polyethylene from spinnerette heads and polypropylene from scaled glassware (for application to spinnerette heads). In these applications, the removal of the solidified waste form reached nearly 100% using sonication techniques. The sound waves effectively chiseled the waste forms from the equipment, breaking the scale into many, many fine particulates, effectively forming a slurry of the original solid "hockey-puck-like" monolith. The acoustic cavitation effectively scoured the equipment surface free of the solidified waste form. ANL is currently investigating the use of this advanced acoustic cavitation technique to remove paraffin build-up from production wells and lateral piping in the field. FNI, ANL, and Nicor Technologies are currently examining the possibility of using this technique to remediate blocked or plugged underground natural gas storage wells. Other potential applications of this advanced acoustic cavitation technique being studied include: disablement and neutralization of land mines and unexploded ordinances, in-situ removal of chlorinated solvents (volatile organic compounds) from groundwater, enhanced oil/water separation, development of a hand held device for decontamination and decommissioning of buildings, and removal of oil and cutting lubricants from scrap aluminum. ANL has been researching the combination of acoustic cavitation (sonication) with advanced oxidation (air, oxygen, ozone, and hydrogen peroxide) techniques for the past five years. Furness-Newburge, Inc. (FNI) has been working with the foundry industry to solve environmental emissions problems and optimize sand/clay/binder reuse for the past eight years. ANL and FNI joined forces in May of 1998 to begin examining the synergies of their independent work efforts and focus on new applications for the joint technology interests. The following text summarizes these efforts by application and give a brief summary of the approach.

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