Patent GB-474971-A (GB)
Title: Improvements in or relating to method of and apparatus for contacting liquid phases such as in the treatment of mineral oils
IPC: B01D11/04
Filed: 1936-02-05
Abstract: <PICT:0474971/III/1> <PICT:0474971/III/2> <PICT:0474971/III/3> In the treatment of liquids with liquids, such as in the solvent extraction of petroleum fractions, the liquids are flowed relatively to each other through a contacting zone in which at least one of the liquids is maintained during the greater part of its passage therethrough in a plurality of separate relatively small streams by means of thin rods or tubes or vertically suspended lengths of chain along which the flow of one of the liquids is initially directed.  The relative flow may be countercurrent, in the same direction at different speeds, transverse, or one liquid may be kept stationary whereby it is used or treated in batches.  The rods or tubes may have irregular cross-sections, and may be provided with irregularities or protuberances to increase their surface area; the tubes may be perforated, and liquid may flow over the inside.  The solvent may be liquid, solid, or vapour at atmospheric temperature and pressure, the conditions during the treatment being such as to maintain it liquid; a mixture of solvents or more than one separate solvent may be used. There may be a temperature gradient along the zone of contact whereby reflux conditions are set up. The individual tubes, rods, or chains are preferably such as to treat the same proportions of liquids and to produce the same degree of treatment.  A number of treatment towers may be connected together, e.g. in series.  Using the jacketed treatment tower 30, shown in Figs. 1 and 3, the heavier liquid, e.g. oil, flows from an inlet E to a chamber 35, through tubes 39 on to rods 31 bearing overlapping discs 32, into tubes 41, and through perforations 42 into a settling chamber 37; it is withdrawn through an outlet 46; the lighter liquid, e.g. solvent enters by a pipe 47, flows between tubes 41 and 43 into the tower 30, collects at the top about the tubes 39, and is withdrawn through outlets 48.  The tubes 41, 43 may be omitted, especially when the liquid in continuous phase preferentially wets the rods 31; baffles may be attached to the inside of the tower 30; the jacket 34 may be divided into sections, and the rods 31 may have interior passages for heat exchanging fluid. Liquid or liquids may be supplied on to or about the rods 31 at an intermediate point or points, e.g. oil when it is being treated simultaneously with a heavy solvent fed from the inlet E and a light solvent fed from the pipe 47. Suitably, as shown in Fig. 3, a feeding chamber 5 is formed at the desired point or points in the tower 30, between sheets 52, 53 fitted with clear unperforated tubes 54 and with perforated tubes 55, through which pass the rods 31; liquid fed through a pipe P to chamber 51 passes through perforations 56 on to or about the rods 31.  Fig. 4 shows a tower on which the relative flow of liquids is transverse.  The tower is divided by plates 141 into compartments 142.  The heavier liquid flows from the top down the rods 31 formed with protuberances in the form of frustum of double cones 32a or of rain-drops; the lighter liquid flows from an inlet pipe Q through the manifold 143 on the right, through the lowest compartment 142, out through the manifold 143 on the left, and into the manifold of the next higher compartment 142, and so on up the tower until withdrawn at the outlet O.  The transverse flow may be right to left through each or any number of compartments 142.  A non-compartmented tower may be used when one transverse flow is sufficient.  When oil is treated simultaneously with light and heavy solvents the oil may be fed in at the top with the heavy solvent or at some intermediate point of the tower.