METHOD OF CLEANING STORAGE TANKS FOR CRUDE OIL AND PETROLEUM DERIVATIVES INVOLVING REUSE OF CLEANING PRODUCTS Russian patent published in 2000 - IPC

FIELD: oil and gas production and petroleum processing. SUBSTANCE: tank is at least partly emptied and a stirring device is installed therein. An oil-containing diluent is then injected into tank to dissolve bottom sediments at optimum temperature maintained by means of steam heaters. Resulting mix is stirred to assume homogeneous state and at least partly pumped off into decanter for further mechanical centrifugal phase separation. Oil phase is settled and returned into feed tanks of refinery installations for further processing. Steam heaters used to heat bottom sediments are at least partly fed with steam produced in steam generators by burning associated gas and/or process gas released in oil heat treatment process and/or in thermal-destruction processes proceeding in processing of petroleum and/or intermediate products, and/or released in processing of oil recovered from oil-containing sediments: tank cleaning products. Associated or process gas is fed into fuel system at temperature 50-70 C and pressure chiefly 3-5 kg/sq. cm. Prior to be burned, gas is preheated to at least 100 C. 15-40% of gas is burned in steam generator and 60-85% in process installations. As water, return condensate with chemically purified fresh water added is used in amounts at least sufficient to replace lost condensate. To heat chemically purified fresh water and/or initial petroleum, residual heat of spent steam and/or steam condensate from petroleum distillation processes is utilized. . EFFECT: intensified tank cleaning process, reduced loss of crude oil and petroleum products, reduced power and external steam (up to 50% more expensive) consumption, and reduced amount of harmful emissions. 22 cl, 1 tbl