Patent ID: 7875120

Claim:
A method of cleaning an industrial tank comprising the steps of: (a) transmitting a first RF signal into the tank to heat contents of the tank to a first predetermined temperature; (b) providing a carbon dioxide critical fluid into the tank; (c) transmitting a second RF signal into the tank to heat the contents and critical fluid to a second predetermined temperature in the range of 200 to 250 degrees Celsius; and (d) heating the critical fluid and the contents of the tank to the second predetermined temperature in order to initiate a reaction of an oxidant in the critical fluid with a portion of the contents of the tank thereby causing hydrocarbons and contaminants to be released from the contents of the tank for extraction as a vapor, liquid or dissolved in the critical fluid; wherein the carbon dioxide critical fluid comprises a mixture of carbon dioxide (CO 2 ) and the oxidant, the CO 2 having a concentration of 80-100%, the oxidant comprising a mixture of nitrous oxide (N 2 O) having a concentration of greater than 0% but less than or equal to 20%, and oxygen (O 2 ) having a concentration of greater than 0% but less than or equal to 20%.