Liquid-liquid centrifugal contacting machines and methods of constructing and operating them

In a centrifugal device for contacting phases of heavy and light densities wherein there is included a rotor mounting a coaxial hollow casing having an outer cylindrical wall to provide a radially extending rotor chamber therein, the device further including a plurality of concentric radially relatively closely spaced annular partition walls surrounding the shaft which have perforations for the passage of the phases therethrough, and means for removing the heavier phase from the outermost portion of the rotor chamber and the lighter phase from the innermost portion of the rotor chamber, the device further including radially extending light phase inlet passageways extending to have communication with the radially outer portion of the rotor chamber and radially extending heavy phase inlet passageways having communication with the radially inner portion of the rotor chamber, and having means for continuously supplying light and heavy phase fluid to said respective inlet passageways;

• the improvement comprising:
• providing a concentric radially spaced, annular, axially uniformly, phase distributing tray system within the rotor chamber, radially spaced from the shaft and into which an inlet passageway empties, the tray system consisting of an annular base wall and radially projecting walls extending therefrom in the form of open-end risers surrounding riser passages through the base wall for flow of the other phase not being dispersed via the tray system, the said base wall having much smaller openings relative to said riser passages and perforations in the said partition walls, which in number, in cross-sectional size, and in location are such, considering their distance axially from the inlet passageway feeding the tray system, that the phase to be dispersed, from one end of the tray system to the other, flows through them under pressure of the tray head developed without countercurrent flow of the other phase through them, the riser walls being of at least such radial extent as to collect a sufficient head of the phase to be dispersed via the tray system to permit this, considering the inflow rate, the radial position of the tray system the relative specific gravities of the phases, and the speed of rotation of the rotor chamber;
• and the riser passages being of such size as to achieve flow of the said other phase through the risers in the continuous phase.

A method of contacting phases of heavy and light densities comprising the steps of:

• providing a rotor mounting a coaxial hollow casing having an outer cylindrical wall forming a radially extending rotor chamber therein which will subject phases contained therein to centrifugal force with rotation about the rotor axis;
• providing concentric radially spaced sieves within the chamber with openings in such sieves;
• providing first phase distributing means in the outer periphery of said chamber and containing therein the light density phase;
• providing second phase distributing means in the inner periphery of said chamber and containing therein the heavy density phase;
• providing phase inlet passageways to said first and second phase distributing means;
• providing both the distributing means with openings, and at least one of them in tray form having a peripherally disposed base with dispersing openings therethrough interspersed with much larger area riser openings therethrough surrounded by radially projecting walls forming open-end risers, the dispersing openings in said base being smaller in area than the sieve openings and in number, in cross-sectional size, and in location being such, considering their distance axially from the inlet passageway feeding the said one distributing means, that the phase to be dispersed from one end axially of the base to the other flows through them under pressure of the head developed without counter-current flow of the other phase through them, the riser walls being of such radial extent, considering inflow rate, radial position in the rotor chamber, the relative specific gravities of the phases, and the speed of rotation of the rotor chamber as to collect a sufficient head to pass the phase being dispersed through the dispersing openings to permit this, without countercurrent flow of the other phase through them, while simultaneously under pressure of the differential head developed passing the said other phase through in the continuous phase;
• ejecting the phases through the openings in both distributing means into the rotor chamber while rotating the rotor, the said phase being dispersed by said one distributing means being distributed into the rotor chamber through said dispersing openings without counterflow of the other phase through them, and the other phase moving through the riser openings in the continuous phase;
• and thereafter passing both phases through the same sieve openings and contacting the one ejected phase directly with the other ejected phase as they move in counterflow.