GB689974A - Improvements in or relating to apparatus for contacting of liquids with liquids or gases - Google Patents

Abstract

A method for mixing relatively immiscibile or partly immiscible fluids consists in passing the fluids through a chamber comprising a mixing zone in which the fluids are agitated by one or more reciprocating perforated plates located within the chamber and extending part way across the chamber leaving a space between the periphery of the plates and the walls of the chamber, and a separating zone into which the mixed fluids are passed from the mixing zone and wherein the mixture is separated into two phases, the said phases being removed separately from the separating zone. In Fig. 1, an extraction tower 1, suitable for use in the counter-current solvent extraction of mineral oils with a selective solvent such as phenol, has inlets 15, 16 and outlets 17, 18 for light <PICT:0689974/III/1> <PICT:0689974/III/2> <PICT:0689974/III/3> <PICT:0689974/III/4> and heavy phases respectively, fixed plates 2 and fixed baffles 7 dividing the tower into mixing zones 4 and settling zones 5. Perforated plates 8 in the mixing zones receive vertical oscillation from a shaft 9 and jets of the liquids below and above the plates are forced upwardly and downwardly respectively through the perforations, whereby the phases are mixed, whilst a proportion of the liquid flows around the periphery of the plates 8. The mixed phases separate in the settling zone 5 and the light phase continues its upward flow whilst the heavy phase continues its downward flow. In Figs. 3 and 4 a container 21 is divided by lateral partitions 23 and has inlets 28 and outlets 30 for a light phase and inlets 29 and outlets 31 for a heavy phase, the two phases flowing countercurrent through the container as a whole. The partitions 23 have conduits 27 for the light phase and conduits 26 for the heavy phase. The mixing plates 24 are mounted for vertical oscillation at one end of each compartment leaving a settling zone 22 at the other end. In operation the light and heavy phases enter each compartment above and below the mixing plates through the conduits or inlets adjacent the plates and are mixed whilst flowing in a concurrent manner through the mixing zone into the settling zone 22 where the phases separate and finally leave the compartment through the conduits or outlets at the end of the settling zone. The phases are pumped through the apparatus and the flow can be assisted by tilting the apparatus. An embodiment for liquid-gas contacting is shown in Fig. 11, wherein the gas flows upwardly and the liquid downwardly and wherein a thin layer of liquid is maintained on top of baffle plates 111 and a vertically oscillating perforated plate 112 in each mixing zone 115 is arranged to be at the liquid-gas interface when it is at the top of its stroke. The phases flow countercurrent through the apparatus as a whole and through the mixing zone 115 and settling zones 116. The several other embodiments described comprise two forms of apparatus, Figs. 5-8 and Fig. 9 (not shown), for liquid-liquid or liquid-gas contacting in which a container is divided by horizontal partitions into a number of individual stages one above the other through which the phases flow concurrently whilst flowing countercurrent through the apparatus as a whole, an apparatus for liquid-liquid extraction in which the flow throughout is countercurrent comprising three horizontally aligned stages without baffles or traps, Fig. 10 (not shown), and a liquid-gas or vapour-contacting tower in which liquid is maintained in a series of annular pools arranged one above the other, Fig. 12 (not shown). Heating or cooling means may be provided. In liquid-liquid extraction, an anti-solvent may be used along with the main extractive solvent.