METHOD FOR THERMOCHEMICAL CLEANING OF RESERVOIRS FOR STORING PETROLEUM PRODUCTS Russian patent published in 1998 - IPC

FIELD: cleaning of reservoirs to remove high-viscosity oil contaminants; environmental control. SUBSTANCE: contaminant chemical composition of contaminant for selecting suitable organic solvent or mixture of solvents. Aqueous solutions of nitrogen-containing salt intended to act as reducing agent and nitrogen-containing salt intended to act as oxidant are prepared in vessels suitable for mixing. Both aqueous solutions are fed separately into intermediate vessel in equimolar stoichiometrical ratio, volume ratio of reducing salt solution-to-oxidant salt solution is about 2:1. Percentage of acid intended to act as reaction activator is adjusted with the help of calibrated scale, followed by adding to aqueous solution nitrogen-containing intended to generate nitrogen and heat. Resulting solution is poured into reservoir to be decontaminated, whereto calculated volume of organic solvent or mixture of solvents is preliminarily poured at solvent(s)-to-contaminants volume ratio from 0.5:1 to 2.5:1.0. Oil phase is removed by adding sufficient amount of process water to form aqueous layer superposed by oil phase, followed by gradually displacing oil phase towards undecontaminated reservoir or towards distillation apparatus. Aqueous phase heavily laden with salts is directed to sewage water treatment system. Inorganic solid residue is extracted from clean reservoir by opening shutter valve in it. EFFECT: higher efficiency. 7 cl, 2 dwg