Abstract: A method for preventing formation of a sediment layer at the bottom of a tank containing a liquid mixture such as crude oil, refinery products and petrochemical products which tends to form a precursor in the form of a thickening precipitation zone above the bottom. The deposit of sediment is prevented by disturbance of the precipitation zone. The disturbance is created in the form of an overall disturbance pattern with local disturbance regions with vibrating bodies such as strings or bells strings excitable to vibrate and immersed in the liquid mixture. Exciting elements including push and pull units cause the strings or bells to vibrate in fundamental and harmonic overtones and deflect components of the mixture as a function of the amplitude of said sound wave components.

Abstract: A method and apparatus for preventing the deposit of sediments from multi-material mixtures, such as crude oil (4), refinery products and petrochemical products, at the bottom of a tank (T), in which the sediments form a precursor in the form of a thickening precipitation zone (4.2). The deposit of sediments is prevented by disturbing the formation of the precipitation zone (4.2). The disturbance is created in an overall disturbance patterns (S) with local disturbance regions (L) according to a disturbance pattern (S) and is brought about by disturbance apparatus (V) in a disturbance zone hydro-kinetically by the supply or removal of crude oil (4) in the disturbance zone through a pipe system (7).

Abstract: To render residues such as thickened sludge and sedimented crude oil or refinery products which collect at the bottom of a tank into pumpable flowable condition, crude oil is taken from an upward region of the tank, pumped upwardly to a suction pump (609)-pressure pump (605) unit (610) located, for example, on top of a floating roof of the tank, the pressurized crude oil taken from the top portion of the tank being reintroduced through a preferably rotating liquefaction lance (13) to a region in the vicinity of the sedimented sludge. The pressure is converted into hydrodynamic energy. Preferably, a plurality of such lances are used, arranged with respect to each other to form eddies or vorteces, to establish flow patterns within the tank, thereby liquefying the sludge or residues and rendering them into pumpable flowable condition for removal from the tank.