GB1242411A - Improvements in or relating to treatment of fluids - Google Patents

Abstract

1,242,411. Processes and apparatus for filtration, catalysis and ion exchange C. M. CHARTERS 10 Jan., 1969 [20 Feb., 1968], No. 8178/68. Headings B1D, B1F and B1J. Fluid (liquid or gas) is continuously treated by a process which comprises continuously supplying fluid to a lower part of a "packed" bed of particulate treatment material located in a container and suspended between the top and the bottom of the container, continuously passing the fluid in upward flow through a lower part of the bed, continuously removing all or part of the fluid from the bed at a location below the upper surface of the bed, allowing treatment material to fall from the bottom of the bed and continuously or intermittently feeding treatment material to an upper part of the bed, the rate of feed of treatment material and the rate of flow of fluid being so chosen that the bed is maintained in a state of equilibrium, the rate at which the treatment material is fed to an upper part of the bed being equal to the rate at which treatment material falls from the bottom of the bed. A "packed" bed is defined as a bed in which the particles thereof remain in contact with each other and thus occupy minimum volume, each particle being substantially immovable in relation to adjacent particles. Downward flow of fluid in the upper part of the bed may assist in the maintenance of the bed; alternatively, part of the fluid supplied to the lower part of the bed may flow upwardly through the upper part of the bed. Two or more such suspended packed beds may be located in the container in vertical juxtaposition, fluid being supplied to and being passed through a lower part of each bed and being removed from each bed at a location below the upper surface of the bed, treatment material being allowed to fall from the bottom of each bed and, except in the case of the lowermost bed, on to the bed immediately beneath and being fed to an upper part of the uppermost bed; additional liquid may be fed to a space between adjacent beds in order to maintain such beds separate. The treatment material falling from the (or the lowermost) bed may, after suitable treatment, be recycled to the upper part of the (or the uppermost) bed. The or each bed may further comprise particles of a solid material different from the treatment material thereby to provide a solids dilution effect. Various embodiments of apparatus in or by means of which the process may be effected are fully described and illustrated. In such apparatus, the feed means and collection means for the supply and removal of fluid to and from the or each bed may be in the form of tubes, either made of porous material or provided with strainers, connected at one end to a supply header and at the other end to a removal header, both headers being intended to be located outside the bed of treatmend material during operation of the process, and/or the container within which the or each bed is located may be provided with a transverse extension at its lower end, means to provide transverse flow of fluid in the extension and means for separately collecting lighter particles, for example of treatment material, and heavier particles, for example of solids dilution material, falling from the bed above the extension. The invention is described with especial reference to ion-exchange, in particular to the treatment of water by ion-exchange, but is stated to be of use in processes of filtration, adsorption, desorption and catalysis.