GB995767A - Improvements in and relating to arrangements for contacting liquids - Google Patents

Abstract

<PICT:0995767/C1/1> An arrangement for contacting liquids comprises a liquid contacting apparatus and pumping apparatus for producing a pulsed feed of one stream of liquid through the contacting apparatus, the pumping apparatus comprising a continual flow pump means associated with valve means for cyclically varying the flow of liquid through a discharge conduit attached either to the pump means or the contacting apparatus communicating with and supplied with liquid from the pump means, thereby correspondingly varying the pressure in the contacting apparatus to produce pulsations in the flow therethrough. Contact between a dispersed phase liquid supplied through a line 3 and a continuous phase liquid supplied through a line 37 is effected in a column 1, the contact being facilitated by the provision of perforated plates 2 in conjunction with the application of pulsations to the continuous phase liquid. The continuous phase liquid is supplied by a pipe 13 to a reservoir 12, from which a centrifugal or rotary positive displacement pump 11 delivers it via the line 37 to the column 1, near the base of the latter. The continuous phase liquid is discharged near the top of the column 1 via a line 8, while the dispersed phase liquid is discharged from the bottom of the column via a line 31 which delivers it to the reservoir 12, where it separates from the continuous phase liquid into a heavy bottom layer 33, where it is discharged via a line 35. The rates of discharge through the lines 8 and 35 are controlled by valves 21 and 36 which are automatically actuated by liquid level controllers 22 and 34 respectively to maintain constant levels of the two liquids in the reservoir 12. Pulsations are imposed on the liquid flow through the column 1 by means of a rotating valve 32 in the line 31, the frequency of the pulsations being variable by varying the speed of the motor rotating the valve. The amplitude of the pulsations can be varied by adjusting a valve 38 in the line 37 if the pump 11 is of centrifugal type, or by altering the speed of the pump rotor if the pump is of rotary positive-displacement type. The space above the liquid in the column 1 is filled with air or other gas which acts as a buffer for the pulsations. In another embodiment, the dispersed phase liquid is not delivered to the reservoir 12, and separation of it from the continuous phase liquid is effected at the base of the column 1. In this case, the pump 11 takes its supply from the bottom of the reservoir 12, and the rotating valve for producing pulsations in the liquid flow is contained in a by-pass line connected between the pump discharge line and the reservoir 12. In either embodiment, the continuous phase liquid may be the heavier of the two liquids, in which case the lighter liquid is introduced at the base of the column (above the entry point of the continuous phase liquid) and is broken into a fine dispersion which travels up the column, separating into a surface layer and being removed at the top of the column. Specification 995,766 is referred to.